Pathogenesis of Exophthalmos and Eyelid Retraction
Graves orbitopathy (GO) is the commonest orbital disease accounting for greater than 85% of bilateral exophthalmos and up to 50%of unilateral exophthalmos as documented in several large series of patients. In addition, 91% of patients with GO presents eyelid retraction at some point in the clinical course of the disease.
Exophthalmos and eyelid retraction although typical are not exclusive of GO: many other orbital and systemic disorders can originate these signs. Because of the fixed volume of the orbit determined by its bony boundary, any orbital space-occupying lesion leads to forward displacement of the eye; however, this condition which is referred to as exophthalmos can also be caused by non space occupying lesions such as third nerve palsy.
In the presence of a globe of normal size and position and with the gaze directed in primary position, eyelid retraction exists when white sclera is visible above (upper lid retraction) and/or underneath (lower lid retraction) the sclero corneal limbus. In GO eyelid retraction and eyelid displacement consecutive to exophthalmos coexist. In addition to GO, eyelid retraction can have a neurologic, myogenic, mechanistic or a miscellaneous number of other aetiologies. Whatever the cause of exophthalmos or eyelid retraction is, both make possible an increased evaporation of tears with drying of the ocular surfaces resulting in pain, reflex tearing and photophobia; the structural integrity of the cornea may also be damaged with possible compromise of the visual function.
Independently from the aetiology, acute onset of exophthalmos and/or eyelid retraction deserve maximum attention. In order to avoid corneal decompensation and waiting for a more definitive treatment, eye lubricants, moisture chambers, swimming goggles, temporary tarsorrhaphies or blepharorrhaphies represent the measures of choice.
Depending on neoplastic, vascular, infectious, inflammatory or malformative causes, exophthalmos is, in the majority of cases, amenable of medical or surgical causative treatment while for endocrine exophthalmos the commonest treatment is surgical and symptomatic and consists in orbital bone decompressions.
Eyelid retraction due to active inflammatory processes such as allergic or contact dermatitis, psoriasic erythrodermatitis, ichthyosis, bullous pemphigoid, iatrogenic or posttraumatic scars and other similar conditions can benefit from medical therapy ranging from topical treatments to systemic antimetabolite and immunosuppressive agents. Dermatitis can be treated with topical corticosteroids; ichthyosis, psoriasis and pemphigoid with topical transxstmoic acid or, when not responding to topical measures, with oral 13 cw retinoic acid or systemic metotrexate, cyclophosfamide, or cyclosporine. Massages and steroid injections can be beneficial in the treatment of recent iatrogenic or posttraumatic scars causing eyelid retraction. The treatment of stable eyelid retraction is basically surgical and mostly consists in lengthening of upper or lower lid retractors complexes. Multiple Z plasty, grafts, or flaps may also be required in order to increase the vertical length of the anterior eyelid lamella.
Owing to their high incidence, and considering that the scarce literature that links exophthalmos and eyelid retraction to ocular surface disorders almost exclusively regards GO, only dysthyroid exophthalmos and dysthyroid eyelid retraction, their influence on alterations of ocular surface and the treatment of these two conditions will be specifically analysed here.
Tear Film Profile in Graves Orbitopathy
In GO, increased palpebral fissure width, exophthalmos, blink rate, lid lag, lagophthalmos, deficit of elevation and poor Bell's phenomenon can all be potentially connected with drying of the ocular surface. Bartley et al. found a high incidence of various signs and symptoms of ocular surface disease in a cohort of 120 patients with GO during a 10-year follow-up. These included conjunctival hyperaemia (34.5%), pain or discomfort (30%), epiphora (20.9%), chemosis (23.3%), corneal staining (10.1%) and non-optic neuropathy-related loss of vision (7.2%). Although some of these findings may regress when the inflammatory component of the disease is well controlled with medical treatment, those resulting from increased exposure of the ocular surface are likely to persist.
According to the findings of Gilbard and Farris, in GO the damage to the ocular surface depends principally on a widened palpebral fissure which leads to increased ocular surface evaporations resulting in an elevated tear film osmolarity similar to that of keratoconjunctivitis sicca. In their series of GO patients, exophthalmos, lid lag and lagophthalmos did not correlate with ocular surface damage, and tear secretion measured by Schirmer test was not abnormal. Increased and not decreased blinking rate was found to be connected with significant ocular surface damage, but this finding was thought to be secondary to damage of the ocular surface. In Gilbard and Farris' series it was not specified whether the included patients were in the inflammatory or in the chronic phase of GO. More recently however, Khurana et al. presented similar results by comparing a population of 30 patients with GO, 15 presenting a short duration and 15 a long duration of their disease, with 30 controls.
Although it was not clear if the 15 patients presenting short duration of GO were or were not active, tear film pH, fluorescein staining, marginal tear strips and Schirmer test values were not different in patients and controls, in fact suggesting not abnormal tear secretion GO. Rose bengal and lissamine green staining intensity scores were significantly higher in patients as compared to controls, indicating the presence of drying epithelial cells in early as well as in late GO patients. Also in this series, an increased blink frequency was noted in patients which was interpreted as a mechanism of incomplete compensation for decreased break-up time, although a significantly low break-up time was found only in late GO patients.
When active GO has been specifically studied, ocular surface damage correlated significantly with a reduced tear secretion, but not with increased exposure of the ocular surface or impaired up gaze. The lacrimal gland physiologically expresses the TSH receptor which, in active GO, can bind with circulating anti TSH receptor autoantibodies contributing in fact to lacrimal gland impairment. Other studies, however, have shown that also in long-lasting GO, the orbital inflammatory process has an effect on the lacrimal gland and this ultimately reflects on its function and, in turn, on tear composition.
Although the literature concerning the ocular surface alteration occurring in GO is not extensive and far from being conclusive, the multifaceted nature of the problem is not disputed. Lacking a specific medical therapy for GO, the functional alterations of the lacrimal gland, which are subsequent to the autoimmune process affecting the whole orbit, can not be specifically cured and artificial tears remain the only medical means for relieving patients' discomfort. On the other hand, an increased palpebral fissure width, which resulted in being mainly responsible for exposure keratopathy and which depends on eyelid retraction and eyelid displacement secondary to exophthalmos, is amenable of effective surgical correction.
Surgical reduction of exophthalmos and widened palpebral fissure, which are the key steps in the surgical treatment of the 'dry eye' in patients with GO, will be discussed below.
Timing of Exophthalmos and Widened Palpebral Fissure Correction in Graves Orbitopathy
The natural course of GO is known to consist in an early dynamic inflammatory phase followed by a static postinflammatory phase, by the contrary the aetiopathogenesis of the disease remains obscure. As a consequence, a specific medical therapy does not exist. Systemic glucocorticoids and orbital radiation therapy, although effective on the inflammatory component of the disease, remain of little efficacy on exophthalmos or increased palpebral fissure width. Prompt restoration of stable euthyroidism and immunosuppression, when necessary, may decrease the duration of the dynamic phase and reverse its tendency to progress towards a more severe symptomatology. Nevertheless, a consistent amount of patients need surgery for functional reasons or aesthetic rehabilitation.
During the inflammatory phase, excluding minor procedures, such as temporary tarsorraphies or blepharorrhaphies, surgery consists in decompressions and it is required when systemic steroids or orbital radiotherapy fail to effectively treat two potentially blinding conditions: optic neuropathy or severe exposure keratopathy. During the post inflammatory phase, after a 6 to 8 month period of stable thyroid metabolism and stable orbitopathy, surgery is indicated for aesthetic, psycho-social rehabilitation and for the treatment of symptoms, such as persisting retro ocular tension or exposure keratopathy, even in presence of minimal aesthetic alterations. Depending on the severity of the symptoms, surgical rehabilitation can be more or less extensive, the full treatment consisting in decompression surgery, squint surgery, eyelid-lengthening and aesthetic eyelid and periorbital procedures.
Decompression surgery causes reduction of exophthalmos as well as reduction of upper and lower eyelid displacement. It may positively influence extraocular muscle restriction, but the displacement of the soft orbital tissues caused by decompression surgery may also induce or worsen strabismus. Eventual squint surgery should therefore follow orbital decompressions but considering that vertical tropias may influence eyelid position, squint surgery should precede an y eyelid lengthening procedure. Finally, when necessary, the finishing touch can be given by aesthetic eyelid and/or periorbital surgery.
In short, surgical rehabilitation needs to respect the given order since the preceding step may influence the step that follows. In particular circumstances, exceptions are possible and the rehabilitation can be favourably sped up by carrying out more than one procedure at the same time.
Correction of Exophthalmos in Graves Orbitopathy
The autoimmune process at the basis of GO leads to accumulation of glucosaminoglycans and collagen within extraocular muscles and orbital fat. The consequent oedema and fibrosis lead to marked swelling of the soft tissues confined within the boundary of the bony orbit with increase of intraorbital pressure leading to venous congestion, exophthalmos and other typical signs and symptoms of GO. Any surgical procedure aimed at decreasing the raised intra orbital pressure and its effects, by means of enlargement of the bony orbit and/or removal of the orbital fat is defined orbital decompression.
Orbital fat decompression was first described by Moore in 1920.A mean exophthalmos reduction of 6 mm and an improvement of extraocular eye motility have been reported by Olivari on a large series of patients, but the same results were not confirmed by other authors. Orbital fat decompression has never reached the popularity of bone decompression due to the feared complications that may be connected with this surgical approach and which may encompass damages to oculomotor ciliary and lacrimal nerves, orbital vas-culature, extraocular eye muscles, optic nerve and the eyeball itself. Recently, however, bone and fat decompression are no longer considered alternatives but had became complementary approaches concurring in tailoring the most adequate treatment to the specific patient's needs.
The history of orbital bone decompression surgery can be dated back to 1911 when Dollinger first proposed orbital enlargement by removing the lateral wall for the cure of exophthalmos. Since then, various osteotomies performed via different routes and involving one or more of the other orbital walls have been proposed. Also in the case of bone orbital decompression, in spite of theoretical expectations, severe complications are rare in clinical practice. The most common complication of this surgical approach is consecutive strabismus, although infraorbital hypoesthesia, sinusitis, lower lid entropion, eyeball dystopia, or more rarely leakage of cerebro spinal fluid, infections involving the central nervous system, damages to the eye and optic nerve or their vasculature, cerebral vasospasm, ischemia and infarction, can occur. Reactivation of GO after rehabilitative bony orbital decompression is another, recently described, rare complication.
In the 1980s, when the number of orbital decompression procedures being performed began to rise, as surgery started to be undertaken not only for functional reasons but also for the aesthetic/psychosocial rehabilitation of Graves patients, the antralethmoidal decompression by a transantral approach, as described by Walsh and Ogura in 1957, was the mainstay technique. The major disadvantage reported with transantral surgery was motility imbalance as high as 52% and therefore alternative procedures were sought in an attempt to decrease the risk of decompression-induced diplopia. In cases of mild exophthalmos, translid antral-ethmoidal decompression appeared to be a valid alternative, with a risk of iatrogenic diplopia in only 4.6% of patients. For more severe exophthalmos, inferomedial decompression was used in combination with lateral decompression. Such procedures, whether performed with separate periorbital incisions or via a coronal approach, were also related with a low incidence of consecutive diplopia.
In 1989, Leone et al, in an attempt to further reduce the effect of decompression surgery on extraocular muscle motility, proposed balancing the decompression by removing the medial and lateral orbital walls while sparing the floor. This technique, which theoretically should have minimised the risk of iatrogenic diplopia, later appeared to be connected with a higher risk for such a complication as compared with removal of the lateral orbital wall alone or with studies in which inferomedial and three-wall techniques were described.
Recently the lateral wall, and in particular its deeper portion, has been described as an elective zone of possible orbital volume expansion, especially if combined with fat decompression. Such a large number of variations illustrates that no single one can be considered the best. An analysis of the current literature on the argument is highly complicated due to the extreme heterogeneity of the patients included in each series, the variation applied to surgical techniques, the use of perioperative glucocorticoids, the difference in timing and modality of assessment of surgical results.
Many variables can affect the results of orbital decompression: volume and location of the osteotomy, amplitude of removal or incision of the periorbita, stage of the orbitopathy at the time of surgery, orbital compliance which refers to distensibility and plasticity of the soft orbital tissues, and preoperative Hertel readings, can all play a role.
At present the removal of the orbital roof is no longer used: minimal is in fact its contribution to orbital decompression and its removal establishes a direct communication between the anterior cranial fossa and the orbital content, making possible the transmission of the pulsation of the internal carotids to the latter including the eyeball. The orbital floor, the medial and the lateral orbital walls are currently removed in the course of decompression surgery, the extension of the osteotomy being dependent on the amount of exophthalmos reduction which is to be achieved.
Traditionally the removal of the medial wall and the floor, known as inferomedial decompression, is used to cure mild to moderate degree of exophthalmos and the lateral wall removal is added when more severe degrees of exophthalmos impose a greater decompression effect. Recently, in a further attempt to minimize the risk of iatrogenic strabismus, it was proposed to start decompression surgery by removing the lateral orbital wall and eventually to increase the effect of decompression by removing the orbital fat or the medial orbital wall leaving the removal of the floor as the very last option.
A number of different surgical routes can be used for decompression purposes, hidden incisions are to be preferred to visible trans-cutaneous approaches, such as Lynch or the mid lower lid incisions which produce exposed scars. Typical ophthalmological routes to inferomedial decompression, are the transcaruncular and the transinferior fornix. The latter also permits lateral decompression, which however is easier if the fornix incision, is coupled with an incision at the lateral canthus. That in fact permits the lower lid to swing outwards and gives a wide access to the lateral wall. This approach first described by McCord in 1981 and known as swinging eyelid is at present widely adopted it gives an excellent exposure of medial inferior and lateral orbital walls and leaves an inconspicuous scar at the lateral canthus. As an alternative the lateral orbital wall can also be approached by means of a separate upper skin crease incision.
The coronal incision implies a more extensive surgical dissection if compared with the swinging eyelid approach or other periorbital incisions but, in turn, provides access to all the orbital walls and the best exposure of the deep lateral orbital wall, which represents an elective zone for orbital expansion. The coronal approach can be performed also in those patients with GO presenting remarkable periorbital swelling or conjunctival chemosis, which may adversely interfere with periorbital incisions. It is the elective approach for minimising the number of periorbital incisions which are necessary to accomplish the full rehabilitation and this can be particularly advantageous in young or black patients.
In addition to this, the coronal incision is to be used when the lateral wall including the lateral orbital rim is completely removed. The coronal approach implies the elevation of a subpe-riosteal plane which, differently than with direct periorbital incision, does not disrupt the anatomical planes of the periorbital region: depressed disfiguring iatrogenic scars due to adhesions between deep and more superficial layers are consequently infrequent. The swinging eyelid approach is to be preferred to the coronal approach in unilateral cases or in male patients with impairing baldness. The swinging eyelid or the transinferior fornix approach can be associated with transconjunctival lower lid blepharoplasty or with lower lid-lengthening procedures speeding up the surgical rehabilitation of GO.
Orbital Decompression by Coronal Approach: Surgical Technique A coronal incision is made with a No. 10 blade from ear to ear, 3 cm behind the hairline. Bleeding from the wound edges is controlled with Raney scalp clips. In the central portion of the skull a subperiosteal plane is created by blunt dissection and laterally a surgical plane is bluntly developed between the deep and the superficial temporalis fascia. Laterally and inferiorly, where the deep temporalis fascia divides into a deeper and a more superficial layer to enclose Yasargil's superficial temporal fat pad, the surgical dissection is carried out directly against the deeper division of the fascia. The forehead flap thus created is then turned down in order to expose the superior and lateral orbital rims.
The supraorbital nerve is set free by chiselling its bony foramen when present and the periorbita, including the trochlea, is dissected off the orbital bones. After this, the temporalis muscle is dissected from its anterior origin with a No. 10 blade and periosteal elevators, leaving sufficient tissue for suturing at the end of surgery. In this way the lateral orbital wall is exposed. A small osteotomy is chiselled behind the lateral orbital rim, then it is extended inferiorly up to the inferior orbital fissure, superiorly and posteriorly up to the dura of the middle cranial fossa by means of bone-nibbling rongeurs and a surgical high-speed drill equipped with a cutting-burr or a diamond-burr tip. During surgical manoeuvres the soft orbital tissues and the temporalis muscle are retracted and protected with malleable orbital retractors.
When small spots of dura are exposed through the thin inner cortical bone of the greater wing of the sphenoid, bone removal is stopped as any further removal may increase the risk of complications without substantially contributing in creating space for orbital expansion. After this a Frazier suction tip is used to fracture the delicate bone of the medial orbital wall and the floor and Blakesly forceps No. 1 and No. 2 are used to remove bony fragments and mucosa of the sinuses.
The bulla ethmoidalis beneath the frontoethmoidal suture is opened towards the orbit from the posterior lacrimal crest up to the orbital apex, and then the orbital floor medial to the infraorbital canal is removed from 0.5 cm behind the inferior orbital rim up to the posterior wall of the maxillary sinus. The posterior two thirds of the maxillary ethmoidal strut are removed creating a wide antrostomy, while the anterior one third of the strut is left intact in order to prevent globe displacement and the possibility of medial entropion or hypoglobus. The removal of the most posterior portion of the maxillary ethmoidal strut together with the orbital process of the palatine bone give access to the sphe-noidal sinus increasing the possibility of apex decompression when necessary.
Finally, the periorbita is incised in order to promote maximal prolapse of the soft orbital tissues into the newly created spaces, the temporalis muscle is sutured back into position with 4-5 interrupted 2/0 Mersilene sutures and, after the insertion of a 3.3 mm diameter end perforated wound drain into each temporalis fossa, the scalp incision is closed with iron staples.
Orbital Decompression by Transinfenor Fornix/Trans Caruncular Swinging Eyelid/Upper Skin Crease Approach: Surgical Technique After the exposure of the inferior fornix by mean of a Desmarres retractor and a malleable órbita retractor, the conjunctiva and lower lid retractor complex are transsected en bloc with a Colorado needle and the inferior orbital rim is exposed.
At that level the periorbit is incised and the medial and inferior orbital walls exposed by developing a subperorbital plane and the bony orbit. In order to obtain the best possible exposure of the medial wall, the bony insertion of the inferior oblique muscle may be detached without consequences, and the con-junctival incision extended upwards, laterally to the caruncle. A separate incision lateral to the caruncle (trans caruncular approach) can possibly be used to address the medical orbital wall when the floor is not to be removed. After this the medial orbital wall and the orbital floor are addressed as for orbital decompression through a coronal approach. With the transinferior fornix approach, however the wide exposure of the orbital floor permits an easy removal of the bony infraorbital canal and the floor lateral to it.
If more decompression is needed the lateral wall can be removed starting the osteotomy from the anterior portion of the inferior orbital fissure by means of bone nibbling rongeurs and by means of a surgical high-speed drill equipped with a cutting-burr or a diamond-burr tip. In order to aid the removal of the upper part of the lateral orbital wall and in particular its anterior superior portion, a lateral canthotomy and lysing of the inferior limb of the lateral canthal tendon can be performed converting, infact, the pure transinferior fornix approach into a swinging eyelid approach. An upper skin crease incision can also be used in combination with the pure inferior fornix or with the swinging eyelid approach if a wider exposure of the lateral orbital wall is to be attained.
The removal of the lateral orbital wall can be carried out up to the dura as described for the coronal approach and as for coronal approach at the end of the procedure the periorbita is incised in order to promote maximal prolapse of the orbital tissues into the newly created spaces. The canthotomy is closed in layers as for a regular canthopexy procedure, the upper lid crease incision only needs approximation of the skin edges while the inferior fornix incision does not need any suturing. Transinferior fornix, swinging eyelid, trans caruncular, and upper skin crease approaches can all be used to remove orbital fat too.
Correction of Lid Retraction in Graves Orbitopathy
In GO, upper and lower lid retraction are due to a combination of inflammation, fibrosis, adrenergic stimulation and restriction of vertical recti muscles. Exophthalmos also contributes in increasing the eyelid aperture by displacing either the upper or the lower lid. Recently the influence of decompressive surgery which leaves the lower lid retractors undisturbed has been reported to similarly contribute to the reduction of upper and lower lid displacemen. Correction of upper or lower lid retraction implies recession of the lid retractors. Spacers are not essential for upper lid lengthening procedures or for the treatment of mild degrees of lower lid retraction that can benefit from free recession of lower lid retractors and lateral canthoplasty.
The surgical correction of more severe forms of lower lid retraction requires interposition of spacer grafts between the tarsus and the recessed retractors to provide height and the necessary stiffness to support the lower lid against gravity. A number of autologous, homologous, xenogenic and synthetic materials have been used but the optimum spacer remains controversial. Among biological materials, ethanol preserved donor sclera has been widely used, but it is of limited availability, carries a risk of transmission of infections and it is associated with recurrent retraction due to graft absorption and fibrosis. Upper lid tarsus is an optimal material but its use is limited by the scarce possibility of harvesting at the donor site.
The stiffness of cartilage grafts may alter eyelid contour and adversely interfere with eyelid motility and down-gaze, the same applies to porous polyethylene sheets. Other synthetic materials such as polytetrafluoroethylene or polyester mesh carry the risk of extrusion. An autogenous hard palate mucosal graft is relatively easy to obtain, is similar to lower lid tarsus in terms of contour, thickness and stiffness, has a mucosal surface, has no risk of rejection and undergoes minimal shrinkage following grafting. Ophthalmic complications of hard palate mucosal grafting are uncommon and usually limited to transient corneal abrasion; morbidity at the donor site encompasses secondary haemorrhages, retarded healing due to oral infections, pain, and rarely oronasal fistula.
Homologous acellular dermal matrix is a processed donor tissue with appropriate consistency for posterior lamella augmentation. One surface is cut through the dermis, the other has an intact basement membrane which provides a structural template that guides conjunctival epithelial migration and repopulation. Homologous acellular dermal matrix represents a valid alternative to hard palate mucosal graft, its use reduces surgical time and eliminates the problem of donor site morbidity, but currently is not available in Europe.
In short, at present, hard palate mucosal graft providing structural and epithelial elements represents the best choice for posterior lamella augmentation in lower lid lengthening, although it may be associated with the disadvantage of not negligible donor site morbidity. In light of this and considering that donor site morbidity may be minimised by meticulous surgical technique and appropriate postoperative care, harvesting and implantation techniques will be given and commented below.
The treatment of persistent upper eyelid retraction is surgical and by far less predictable than that of lower lid. The medical therapy of upper lid retraction with a-blockers eye drops is scantly effective and topical or systemic therapy with post-ganglial adrenergic blocker drugs such as guanethidine is connected with several undesirable side effects. Botulinum toxin can also be an option, its effect however is limited in time and multiple injections are required. With botulinum toxin temporary under or over correction can occur. Deficit of elevation and paralysis of the orbicularis muscle may also be possible, undesirable complications in GO patients who are at risk for corneal exposure.
Considering that upper eyelid lengthening is one of the last steps of the long-lasting and somewhat exhausting surgical rehabilitation of patients with GO and that, although several surgical techniques for its cure have been proposed, an elective method is lacking, it is strongly advisable to use the quickest and simplest possible technique.
In keeping with this, a quick, systematic approach suitable for every degree of upper eyelid retraction with or without alteration of eyelid contour such as lateral or medial peaks is given in table 3 and the related surgical techniques will be described and commented below.
Lower Lid Lengthening Surgical Procedure
Hard Palate Mucosal Graft Harvesting
Prior to surgery a careful in office inspection of the donor site is mandatory for a correct selection of candidates, and at surgery the location of the donor site is fundamental in order not to bare the periosteum or being obliged to apply excessive diathermy as this may cause bone necrosis. Prior to surgery, any lesion suspected for malignancy should be biopsied; oral candidiasis in immunocom promised patients should be cured since postoperative granulation at the donor site can be delayed; the presence of exostosis such as torus palatinus or prominent palatal roots of teeth should be considered since the thin overlying mucosa of these areas may lead to unwanted periosteal or root damage at surgery.
The presence of a bifid uvula or a muscular diastasis of the soft palate can be an important clue to an underlying bony palatal cleft that is not otherwise evident and which represents an absolute contraindication for mucosal harvesting. However, the presence of small isolated clefts of the bony palate may escape clinical detection due to the presence of an overlying intact mucosa and to their asymptomatic nature. Besides iatrogenic damage to the bone and periosteum and infectious causes, fistulas may also develop from such a malformation.
At surgery the donor site should be placed between the median raphe and the alveolar process and not extended posteriorly behind the first molar. At this level the submucosa is well defined and partial thickness mucosal dissection can be easily carried out anteriorly to the neurovascular bundle emerging from the greater palatine foramen. The latter can in fact be located medially to the third or to the second molar. Areas close to the gingival border or to the median raphe are not suitable as donor sites since the risk of bone necrosis secondary to periosteal damage is much higher here: at these levels the mucosa is in fact directly attached to the periosteum without interposition of the submucosa.
Although hard palate mucosal grafts can be harvested under local anaesthesia, general anaesthesia is to be preferred for the patient's comfort. The mouth is open with a Jonson mouth spreader. The hard palate is dried and a dermographic pen is used to mark the graft size that should be about twice the degree of lower lid retraction in width. Submucosal infiltration with lidocaine 2% with epineph-rine 1:80,000 is then carried out to aid haemostasis and dissection.
The harvesting is carried out first using a No. 15 Bard-Parker blade to incise the marked area, then with a disposable angled keratotome and surgical forceps to dissect the submucosal plane and elevate the graft. The use of suction and of a tongue depressor by the surgical assistant will greatly aid in this phase. Excessive diathermy should be avoided at all times, and at the end of surgery, in order to control oozing at the donor site a rolled vaseline or haemostatic gauze can be inserted into the mucosal defect and kept in place with a previously prepared palatal shell, digital pressure on the shell can also be applied for some time and fibrin glue used if necessary. Bleeding from major vessels can be controlled with injections of local anaesthetic within the bleeding area or into the palatine foramen or with ligation if necessary.
The mucosa of the graft consisting of epithelium and thick collagenous lamina propria is then prepared for the recipient site by removing the fatty submucosa.
Large spectrum systemic antibiotics and antiseptic mouthwashes are recommended for 1 week after surgery. Soreness at the donor site for a few days after surgery is common especially during eating; custom-made acrylic palatal stents which aids haemostasis and favourite granulation can increase the patient's comfort.
Lower Lid Lengthening
Topical oxybuprocaine HC1 0.4% drops are applied to eye, then 0.5-1 ml of lidocaine 2% with epinephrine 1:80,000 is administered subconjunctivally along the inferior margin of the tarsal plate and 0.25 ml of the same anaesthetic is administrated subcutaneously into the centre of the lower lid. A 5-0 silk traction suture is placed in the centre of the lower lid along the eyelid margin and the eyelid is everted over a Desmarres retractor. An infratarsal incision is done for the whole length of the tarsal plate with a No. 15 Bard-Parker blade and the conjunctiva lower lid retractor complex transsected en bloc.
A preseptal plane is then bluntly developed in order to adequately recess the lower lid retractors and conjunctiva. Bleeding is easily controlled with bipolar diathermy. After this a 6.0 absorbable suture is used to suture the hard palate mucosal graft into place, between the border of the conjunctiva lower lid retractors complex and the inferior border of the tarsal plate, the mucosal surface facing the eyeball. Multiple steri-strips are applied on the lid skin in order to immobilize lid and graft in a correct position for a few days after surgery. No bandage is applied, but ice compresses are recommended for a few hours after surgery. Artificial tears are also prescribed to implement patient's comfort.
Upper Lid Lengthening
Sutureless Transconjunctival Müllerectomy Topical oxybuprocaine HC1 0.4% drops are applied to the eye, then 0.25 ml of lidocaine 2% with epinephrine 1:80,000 is administered subcutaneously into the centre of the upper eyelid. A 5-0 silk traction suture is placed in the centre of the upper eyelid along the eyelid margin and the eyelid everted over a Desmarres retractor. Then 0.5 ml of lidocaine 2% with epinephrine 1:80,000 is injected close to the superior tarsal border subconjunctivally and between Müller's muscle and the levator aponeurosis over the whole length of the eyelid.
A high temperature battery-powered cautery is used to incise the conjunctiva along and just above the superior tarsal border. After this the conjunctiva is separated from Müller's muscle first with sharp then with blunt dissection. In this way the superior fornix is approached (fig. 7a). Müller's muscle is then grasped with fine-toothed forceps at the lateral aspect, the tension exerted with the Desmarres retractor is relieved, and a plane can easily be developed between Müller's muscle and the inferior surface of the levator aponeurosis by spreading the blade of blunt pointed straight scissors. The distal insertion of the muscle is gently cauterised, afterwards severed with scissors. The proximal insertion is then similarly addressed. At the end of the procedure the conjunctiva is not sutured.
Any possible lateral or medial alteration of the eyelid contour is treated by means of weakening the levator aponeurosis at the level of the peak. This is achieved by means of several small horizontal incisions which transform the aponeurosis under consideration in a kind of network increasing in fact its vertical length. At the end of the procedure the traction suture which was placed in the centre of the eyelid is removed. No bandage is applied but ice compresses are recommended for a few hours after surgery. Artificial tears are prescribed to implement the patient's comfort.
Sutureless transconjunctival Müllerectomy is an effective procedure for the cure of mild degree of upper eyelid retractions up to 2-3 mm. It does not interfere with the position of the skin crease since surgical dissection is carried out under the levator aponeurosis. It takes around lOmin/eyelid, reintervention for under- or overcorrection are rare and usually due to surgical mistakes as incomplete excision of Müller's muscle or damage to the aponeurosis of the levator muscle. Tear secretion may be reduced after Müllerectomy by the conjunctival approach. Nevertheless, the clinical risk of dry eye is low, and counterbalanced by the usually good functional and cosmetic results of the procedure.
Free En-Bloc Recession of Conjunctiva-Levator Complex by Anterior Approach (Blepharotomy)
This technique was developed by Leo Koornneef one of the most bright minded and talented surgeons in the field of orbit and ophthalmic plastic surgery of the 1980s and 1990s. Because of his untimely death he was unable to publish his idea, nevertheless he could present it at meetings and teach it to several of his fellows including myself.
Topical oxybuprocaine HC1 0.4% drops are applied to the eye, the skin crease is lined with a surgical skin marker. Then 0.5-1 ml of lidocaine 2%with epinephrine 1:80,000 is injected close to the superior tarsal border subcuta-neously and between the orbicularis muscle and levator aponeurosis over the whole length of the eyelid.
An incision is made along the line previously drawn at the level of the upper skin crease through the skin orbicularis layer using a No. 15 Bard Parker blade. Then further dissection is carried out with spring scissors in order to expose the levator aponeurosis and the orbital septum. The orbital septum is opened along the whole length of the eyelid. After this, an en bloc, full thickness levator aponeurosis-Müller's conjunctiva incision is carried out just above the upper border of the tarsal plate: the levator-conjunctiva complex is grasped with fine-toothed forceps in the central portion of the upper lid, and after a gentle localised cauterisation, spring scissors are used to start the incision as a buttonhole. Then the first incision is extended laterally and medially preceded by gentle cauterisation of the levator-conjunctival complex. If a lateral flare is present the deformity is corrected by means of a graded vertical cut through the levator-conjunctiva complex at the level of the lateral horn of the aponeurosis.
The desired degree of lengthening is checked, against gravity, by closing the skin with a temporary suture positioned in the centre of the lid and bringing the patient to a sitting position. At surgery, a couple of millimetres of over-correction are advisable at surgery in order to compensate for postoperative retraction. When the desired level is obtained, a careful inspection of the wound is carried out and any bleeding point cauterised. Finally, the blepharotomy is closed by carefully suturing the skin only, with a running interlocked 6-0 Dermalon suture which should stay in place for 1 week. No bandage is applied but ice compresses are recommended for a few hours after surgery.
Free En-Bloc Recession of Conjunctiva Levator Complex by Sutureless Posterior Approach
Topical oxybuprocaine HC10.4% drops are applied to the eye, then 0.25ml of lidocaine 2% with epinephrine 1:80.000 is administered subcutaneously into the centre of the upper eyelid. A 5-0 silk traction suture is placed in the centre of the upper eyelid along the eyelid margin and the eyelid everted over a Desmarres retractor. Then 0.5 ml of lidocaine 2%with epinephrine 1:80,000 is injected close to the superior tarsal border between levator aponeurosis and orbicularis muscle along the whole length of the eyelid. After a gentle localised cauterisation, spring scissors are used to start a buttonhole incision through the conjunctiva-levator complex in the central portion of the everted eyelid.
Through the buttonhole incision, by spreading the blades of blunt spring scissors, a plane is easily developed between the orbicularis muscle and the anterior surface of the levator aponeurosis. Then the buttonhole incision is extended laterally and medially; in order to minimize bleeding, gentle cauterisation of the conjunctiva-levator complex that is to be severed always goes before any extension of the incision. The incision is carried out just above the upper margin of the tarsal plate in bilateral cases or at a higher level in monolateral upper lid retraction. In this way, in monolateral cases, the skin insertion of the levator aponeurosis is left undisturbed, the skin crease does not rise after surgery and symmetry with the contralateral side is preserved.
The levator aponeurosis and orbital septum are bluntly separated from the orbicularis muscle in order to promote recession of the conjunctiva-levator complex. If a lateral flare is present, the deformity is addressed as for the anterior approach. Also with the posterior approach, eyelid level and contour are repeatedly checked, against gravity, by bringing the patient to a sitting position since when the desired lengthening is achieved. A couple of millimetres of overcorrection at surgery are again advisable in order to compensate for the expected postoperative retraction.
Before the end of the procedure a careful inspection of the wound is carried out and eventual bleeding point cauterised. Finally, the traction suture which was placed in the centre of the eyelid is removed. No bandage is applied but ice compresses are recommended for a few hours after surgery. Artificial tears are prescribed to implement the patient's comfort.
Free en-bloc resection of conjunctiva levator complex performed via an anterior or a sutureless posterior approach is an effective technique for the treatment of medium to severe degrees of upper lid retraction. The results are however not always predictable and reintervention may be necessary. Several intraoperative factors may affect the setting of the upper eyelid height, their consideration may aid in increasing success. Intravenous sedatives interfere with the alertness of the patient and with his collaboration in setting eyelid position, thus these drugs should be used only when it is strictly necessary.
Povidone iodine is an adrenergic-blocking agent. Preoperative irrigation of the conjunctival sac with this solution will result in a paralysis of Miiller's muscle and should therefore be avoided. Paralysis of levator and orbicularis muscle induced by local anaesthetic and the contraction of Miiller's muscle induced by local anaesthetics containing epinephrine are variables that may interfere with the position of the upper eyelid. These variables can be partially controlled if the dose of anaesthetic, its concentration of epinephrine, the sites and the pressure of injection are maintained constant. In order to include the effect of gravity on eyelid height, this should be set by bringing the patient to a sitting position.
The anterior approach may be more desirable to many surgeons since it is the more common technique for ptosis surgery. With this approach, particular attention should be paid to the suture of the skin in order to avoid the risk of postoperative fistulas. The posterior approach cannot be performed in extreme degrees of retraction in which the tarsus cannot be everted, but it is the elective treatment in dark skinned patients in which an unpleasant scar may result from an anterior approach.
A full-thickness incision of conjunctiva levator complex may easily create a flat eyelid contour, if dissection is carried out too far medially. Careful medial dissection also prevents possible nasal droops that are often difficult to be corrected. The graded incision of the lateral horn of the aponeurosis in the case of lateral flare should be vertical or rather parallel to the ductules of the lacrimal gland to avoid any damage to these structures.
In none of the three aforementioned techniques is the conjunctiva sutured at the end of surgery. This prevents possible suture related corneal erosions and leaves a natural drainage with reduction of postoperative ecchymosis. As previously mentioned, pressure bandages are not applied after surgery and no particular treatments except ice compresses and elevation of the head at sleeping time are required in the immediate postoperative period. In the case that after surgery the operated eyelid or a part of it begins to retract, the patient should be instructed to massage the lid downward while looking upward in order to maintain the eyelid at the physiological position. In the case of posterior approaches, vigorous massages may be started soon after surgery while in the case of anterior approach they must be delayed for at least 2 weeks, in order to avoid dehis cence of the surgical wound and possible fistulas.
Conclusions
GO is the commonest cause of exophthalmos and eyelid retraction. These two aesthetic and functional disabling conditions are amenable to effective surgical treatment. Relatively simple techniques can be used to correct eyelid retraction while more elaborated procedures are required to treat exophthalmos and any possible associated alteration of the ocular surface.
Graves orbitopathy (GO) is the commonest orbital disease accounting for greater than 85% of bilateral exophthalmos and up to 50%of unilateral exophthalmos as documented in several large series of patients. In addition, 91% of patients with GO presents eyelid retraction at some point in the clinical course of the disease.
Exophthalmos and eyelid retraction although typical are not exclusive of GO: many other orbital and systemic disorders can originate these signs. Because of the fixed volume of the orbit determined by its bony boundary, any orbital space-occupying lesion leads to forward displacement of the eye; however, this condition which is referred to as exophthalmos can also be caused by non space occupying lesions such as third nerve palsy.
In the presence of a globe of normal size and position and with the gaze directed in primary position, eyelid retraction exists when white sclera is visible above (upper lid retraction) and/or underneath (lower lid retraction) the sclero corneal limbus. In GO eyelid retraction and eyelid displacement consecutive to exophthalmos coexist. In addition to GO, eyelid retraction can have a neurologic, myogenic, mechanistic or a miscellaneous number of other aetiologies. Whatever the cause of exophthalmos or eyelid retraction is, both make possible an increased evaporation of tears with drying of the ocular surfaces resulting in pain, reflex tearing and photophobia; the structural integrity of the cornea may also be damaged with possible compromise of the visual function.
Independently from the aetiology, acute onset of exophthalmos and/or eyelid retraction deserve maximum attention. In order to avoid corneal decompensation and waiting for a more definitive treatment, eye lubricants, moisture chambers, swimming goggles, temporary tarsorrhaphies or blepharorrhaphies represent the measures of choice.
Depending on neoplastic, vascular, infectious, inflammatory or malformative causes, exophthalmos is, in the majority of cases, amenable of medical or surgical causative treatment while for endocrine exophthalmos the commonest treatment is surgical and symptomatic and consists in orbital bone decompressions.
Eyelid retraction due to active inflammatory processes such as allergic or contact dermatitis, psoriasic erythrodermatitis, ichthyosis, bullous pemphigoid, iatrogenic or posttraumatic scars and other similar conditions can benefit from medical therapy ranging from topical treatments to systemic antimetabolite and immunosuppressive agents. Dermatitis can be treated with topical corticosteroids; ichthyosis, psoriasis and pemphigoid with topical transxstmoic acid or, when not responding to topical measures, with oral 13 cw retinoic acid or systemic metotrexate, cyclophosfamide, or cyclosporine. Massages and steroid injections can be beneficial in the treatment of recent iatrogenic or posttraumatic scars causing eyelid retraction. The treatment of stable eyelid retraction is basically surgical and mostly consists in lengthening of upper or lower lid retractors complexes. Multiple Z plasty, grafts, or flaps may also be required in order to increase the vertical length of the anterior eyelid lamella.
Owing to their high incidence, and considering that the scarce literature that links exophthalmos and eyelid retraction to ocular surface disorders almost exclusively regards GO, only dysthyroid exophthalmos and dysthyroid eyelid retraction, their influence on alterations of ocular surface and the treatment of these two conditions will be specifically analysed here.
Tear Film Profile in Graves Orbitopathy
In GO, increased palpebral fissure width, exophthalmos, blink rate, lid lag, lagophthalmos, deficit of elevation and poor Bell's phenomenon can all be potentially connected with drying of the ocular surface. Bartley et al. found a high incidence of various signs and symptoms of ocular surface disease in a cohort of 120 patients with GO during a 10-year follow-up. These included conjunctival hyperaemia (34.5%), pain or discomfort (30%), epiphora (20.9%), chemosis (23.3%), corneal staining (10.1%) and non-optic neuropathy-related loss of vision (7.2%). Although some of these findings may regress when the inflammatory component of the disease is well controlled with medical treatment, those resulting from increased exposure of the ocular surface are likely to persist.
According to the findings of Gilbard and Farris, in GO the damage to the ocular surface depends principally on a widened palpebral fissure which leads to increased ocular surface evaporations resulting in an elevated tear film osmolarity similar to that of keratoconjunctivitis sicca. In their series of GO patients, exophthalmos, lid lag and lagophthalmos did not correlate with ocular surface damage, and tear secretion measured by Schirmer test was not abnormal. Increased and not decreased blinking rate was found to be connected with significant ocular surface damage, but this finding was thought to be secondary to damage of the ocular surface. In Gilbard and Farris' series it was not specified whether the included patients were in the inflammatory or in the chronic phase of GO. More recently however, Khurana et al. presented similar results by comparing a population of 30 patients with GO, 15 presenting a short duration and 15 a long duration of their disease, with 30 controls.
Although it was not clear if the 15 patients presenting short duration of GO were or were not active, tear film pH, fluorescein staining, marginal tear strips and Schirmer test values were not different in patients and controls, in fact suggesting not abnormal tear secretion GO. Rose bengal and lissamine green staining intensity scores were significantly higher in patients as compared to controls, indicating the presence of drying epithelial cells in early as well as in late GO patients. Also in this series, an increased blink frequency was noted in patients which was interpreted as a mechanism of incomplete compensation for decreased break-up time, although a significantly low break-up time was found only in late GO patients.
When active GO has been specifically studied, ocular surface damage correlated significantly with a reduced tear secretion, but not with increased exposure of the ocular surface or impaired up gaze. The lacrimal gland physiologically expresses the TSH receptor which, in active GO, can bind with circulating anti TSH receptor autoantibodies contributing in fact to lacrimal gland impairment. Other studies, however, have shown that also in long-lasting GO, the orbital inflammatory process has an effect on the lacrimal gland and this ultimately reflects on its function and, in turn, on tear composition.
Although the literature concerning the ocular surface alteration occurring in GO is not extensive and far from being conclusive, the multifaceted nature of the problem is not disputed. Lacking a specific medical therapy for GO, the functional alterations of the lacrimal gland, which are subsequent to the autoimmune process affecting the whole orbit, can not be specifically cured and artificial tears remain the only medical means for relieving patients' discomfort. On the other hand, an increased palpebral fissure width, which resulted in being mainly responsible for exposure keratopathy and which depends on eyelid retraction and eyelid displacement secondary to exophthalmos, is amenable of effective surgical correction.
Surgical reduction of exophthalmos and widened palpebral fissure, which are the key steps in the surgical treatment of the 'dry eye' in patients with GO, will be discussed below.
Timing of Exophthalmos and Widened Palpebral Fissure Correction in Graves Orbitopathy
The natural course of GO is known to consist in an early dynamic inflammatory phase followed by a static postinflammatory phase, by the contrary the aetiopathogenesis of the disease remains obscure. As a consequence, a specific medical therapy does not exist. Systemic glucocorticoids and orbital radiation therapy, although effective on the inflammatory component of the disease, remain of little efficacy on exophthalmos or increased palpebral fissure width. Prompt restoration of stable euthyroidism and immunosuppression, when necessary, may decrease the duration of the dynamic phase and reverse its tendency to progress towards a more severe symptomatology. Nevertheless, a consistent amount of patients need surgery for functional reasons or aesthetic rehabilitation.
During the inflammatory phase, excluding minor procedures, such as temporary tarsorraphies or blepharorrhaphies, surgery consists in decompressions and it is required when systemic steroids or orbital radiotherapy fail to effectively treat two potentially blinding conditions: optic neuropathy or severe exposure keratopathy. During the post inflammatory phase, after a 6 to 8 month period of stable thyroid metabolism and stable orbitopathy, surgery is indicated for aesthetic, psycho-social rehabilitation and for the treatment of symptoms, such as persisting retro ocular tension or exposure keratopathy, even in presence of minimal aesthetic alterations. Depending on the severity of the symptoms, surgical rehabilitation can be more or less extensive, the full treatment consisting in decompression surgery, squint surgery, eyelid-lengthening and aesthetic eyelid and periorbital procedures.
Decompression surgery causes reduction of exophthalmos as well as reduction of upper and lower eyelid displacement. It may positively influence extraocular muscle restriction, but the displacement of the soft orbital tissues caused by decompression surgery may also induce or worsen strabismus. Eventual squint surgery should therefore follow orbital decompressions but considering that vertical tropias may influence eyelid position, squint surgery should precede an y eyelid lengthening procedure. Finally, when necessary, the finishing touch can be given by aesthetic eyelid and/or periorbital surgery.
In short, surgical rehabilitation needs to respect the given order since the preceding step may influence the step that follows. In particular circumstances, exceptions are possible and the rehabilitation can be favourably sped up by carrying out more than one procedure at the same time.
Correction of Exophthalmos in Graves Orbitopathy
The autoimmune process at the basis of GO leads to accumulation of glucosaminoglycans and collagen within extraocular muscles and orbital fat. The consequent oedema and fibrosis lead to marked swelling of the soft tissues confined within the boundary of the bony orbit with increase of intraorbital pressure leading to venous congestion, exophthalmos and other typical signs and symptoms of GO. Any surgical procedure aimed at decreasing the raised intra orbital pressure and its effects, by means of enlargement of the bony orbit and/or removal of the orbital fat is defined orbital decompression.
Orbital fat decompression was first described by Moore in 1920.A mean exophthalmos reduction of 6 mm and an improvement of extraocular eye motility have been reported by Olivari on a large series of patients, but the same results were not confirmed by other authors. Orbital fat decompression has never reached the popularity of bone decompression due to the feared complications that may be connected with this surgical approach and which may encompass damages to oculomotor ciliary and lacrimal nerves, orbital vas-culature, extraocular eye muscles, optic nerve and the eyeball itself. Recently, however, bone and fat decompression are no longer considered alternatives but had became complementary approaches concurring in tailoring the most adequate treatment to the specific patient's needs.
The history of orbital bone decompression surgery can be dated back to 1911 when Dollinger first proposed orbital enlargement by removing the lateral wall for the cure of exophthalmos. Since then, various osteotomies performed via different routes and involving one or more of the other orbital walls have been proposed. Also in the case of bone orbital decompression, in spite of theoretical expectations, severe complications are rare in clinical practice. The most common complication of this surgical approach is consecutive strabismus, although infraorbital hypoesthesia, sinusitis, lower lid entropion, eyeball dystopia, or more rarely leakage of cerebro spinal fluid, infections involving the central nervous system, damages to the eye and optic nerve or their vasculature, cerebral vasospasm, ischemia and infarction, can occur. Reactivation of GO after rehabilitative bony orbital decompression is another, recently described, rare complication.
In the 1980s, when the number of orbital decompression procedures being performed began to rise, as surgery started to be undertaken not only for functional reasons but also for the aesthetic/psychosocial rehabilitation of Graves patients, the antralethmoidal decompression by a transantral approach, as described by Walsh and Ogura in 1957, was the mainstay technique. The major disadvantage reported with transantral surgery was motility imbalance as high as 52% and therefore alternative procedures were sought in an attempt to decrease the risk of decompression-induced diplopia. In cases of mild exophthalmos, translid antral-ethmoidal decompression appeared to be a valid alternative, with a risk of iatrogenic diplopia in only 4.6% of patients. For more severe exophthalmos, inferomedial decompression was used in combination with lateral decompression. Such procedures, whether performed with separate periorbital incisions or via a coronal approach, were also related with a low incidence of consecutive diplopia.
In 1989, Leone et al, in an attempt to further reduce the effect of decompression surgery on extraocular muscle motility, proposed balancing the decompression by removing the medial and lateral orbital walls while sparing the floor. This technique, which theoretically should have minimised the risk of iatrogenic diplopia, later appeared to be connected with a higher risk for such a complication as compared with removal of the lateral orbital wall alone or with studies in which inferomedial and three-wall techniques were described.
Recently the lateral wall, and in particular its deeper portion, has been described as an elective zone of possible orbital volume expansion, especially if combined with fat decompression. Such a large number of variations illustrates that no single one can be considered the best. An analysis of the current literature on the argument is highly complicated due to the extreme heterogeneity of the patients included in each series, the variation applied to surgical techniques, the use of perioperative glucocorticoids, the difference in timing and modality of assessment of surgical results.
Many variables can affect the results of orbital decompression: volume and location of the osteotomy, amplitude of removal or incision of the periorbita, stage of the orbitopathy at the time of surgery, orbital compliance which refers to distensibility and plasticity of the soft orbital tissues, and preoperative Hertel readings, can all play a role.
At present the removal of the orbital roof is no longer used: minimal is in fact its contribution to orbital decompression and its removal establishes a direct communication between the anterior cranial fossa and the orbital content, making possible the transmission of the pulsation of the internal carotids to the latter including the eyeball. The orbital floor, the medial and the lateral orbital walls are currently removed in the course of decompression surgery, the extension of the osteotomy being dependent on the amount of exophthalmos reduction which is to be achieved.
Traditionally the removal of the medial wall and the floor, known as inferomedial decompression, is used to cure mild to moderate degree of exophthalmos and the lateral wall removal is added when more severe degrees of exophthalmos impose a greater decompression effect. Recently, in a further attempt to minimize the risk of iatrogenic strabismus, it was proposed to start decompression surgery by removing the lateral orbital wall and eventually to increase the effect of decompression by removing the orbital fat or the medial orbital wall leaving the removal of the floor as the very last option.
A number of different surgical routes can be used for decompression purposes, hidden incisions are to be preferred to visible trans-cutaneous approaches, such as Lynch or the mid lower lid incisions which produce exposed scars. Typical ophthalmological routes to inferomedial decompression, are the transcaruncular and the transinferior fornix. The latter also permits lateral decompression, which however is easier if the fornix incision, is coupled with an incision at the lateral canthus. That in fact permits the lower lid to swing outwards and gives a wide access to the lateral wall. This approach first described by McCord in 1981 and known as swinging eyelid is at present widely adopted it gives an excellent exposure of medial inferior and lateral orbital walls and leaves an inconspicuous scar at the lateral canthus. As an alternative the lateral orbital wall can also be approached by means of a separate upper skin crease incision.
The coronal incision implies a more extensive surgical dissection if compared with the swinging eyelid approach or other periorbital incisions but, in turn, provides access to all the orbital walls and the best exposure of the deep lateral orbital wall, which represents an elective zone for orbital expansion. The coronal approach can be performed also in those patients with GO presenting remarkable periorbital swelling or conjunctival chemosis, which may adversely interfere with periorbital incisions. It is the elective approach for minimising the number of periorbital incisions which are necessary to accomplish the full rehabilitation and this can be particularly advantageous in young or black patients.
In addition to this, the coronal incision is to be used when the lateral wall including the lateral orbital rim is completely removed. The coronal approach implies the elevation of a subpe-riosteal plane which, differently than with direct periorbital incision, does not disrupt the anatomical planes of the periorbital region: depressed disfiguring iatrogenic scars due to adhesions between deep and more superficial layers are consequently infrequent. The swinging eyelid approach is to be preferred to the coronal approach in unilateral cases or in male patients with impairing baldness. The swinging eyelid or the transinferior fornix approach can be associated with transconjunctival lower lid blepharoplasty or with lower lid-lengthening procedures speeding up the surgical rehabilitation of GO.
Orbital Decompression by Coronal Approach: Surgical Technique A coronal incision is made with a No. 10 blade from ear to ear, 3 cm behind the hairline. Bleeding from the wound edges is controlled with Raney scalp clips. In the central portion of the skull a subperiosteal plane is created by blunt dissection and laterally a surgical plane is bluntly developed between the deep and the superficial temporalis fascia. Laterally and inferiorly, where the deep temporalis fascia divides into a deeper and a more superficial layer to enclose Yasargil's superficial temporal fat pad, the surgical dissection is carried out directly against the deeper division of the fascia. The forehead flap thus created is then turned down in order to expose the superior and lateral orbital rims.
The supraorbital nerve is set free by chiselling its bony foramen when present and the periorbita, including the trochlea, is dissected off the orbital bones. After this, the temporalis muscle is dissected from its anterior origin with a No. 10 blade and periosteal elevators, leaving sufficient tissue for suturing at the end of surgery. In this way the lateral orbital wall is exposed. A small osteotomy is chiselled behind the lateral orbital rim, then it is extended inferiorly up to the inferior orbital fissure, superiorly and posteriorly up to the dura of the middle cranial fossa by means of bone-nibbling rongeurs and a surgical high-speed drill equipped with a cutting-burr or a diamond-burr tip. During surgical manoeuvres the soft orbital tissues and the temporalis muscle are retracted and protected with malleable orbital retractors.
When small spots of dura are exposed through the thin inner cortical bone of the greater wing of the sphenoid, bone removal is stopped as any further removal may increase the risk of complications without substantially contributing in creating space for orbital expansion. After this a Frazier suction tip is used to fracture the delicate bone of the medial orbital wall and the floor and Blakesly forceps No. 1 and No. 2 are used to remove bony fragments and mucosa of the sinuses.
The bulla ethmoidalis beneath the frontoethmoidal suture is opened towards the orbit from the posterior lacrimal crest up to the orbital apex, and then the orbital floor medial to the infraorbital canal is removed from 0.5 cm behind the inferior orbital rim up to the posterior wall of the maxillary sinus. The posterior two thirds of the maxillary ethmoidal strut are removed creating a wide antrostomy, while the anterior one third of the strut is left intact in order to prevent globe displacement and the possibility of medial entropion or hypoglobus. The removal of the most posterior portion of the maxillary ethmoidal strut together with the orbital process of the palatine bone give access to the sphe-noidal sinus increasing the possibility of apex decompression when necessary.
Finally, the periorbita is incised in order to promote maximal prolapse of the soft orbital tissues into the newly created spaces, the temporalis muscle is sutured back into position with 4-5 interrupted 2/0 Mersilene sutures and, after the insertion of a 3.3 mm diameter end perforated wound drain into each temporalis fossa, the scalp incision is closed with iron staples.
Orbital Decompression by Transinfenor Fornix/Trans Caruncular Swinging Eyelid/Upper Skin Crease Approach: Surgical Technique After the exposure of the inferior fornix by mean of a Desmarres retractor and a malleable órbita retractor, the conjunctiva and lower lid retractor complex are transsected en bloc with a Colorado needle and the inferior orbital rim is exposed.
At that level the periorbit is incised and the medial and inferior orbital walls exposed by developing a subperorbital plane and the bony orbit. In order to obtain the best possible exposure of the medial wall, the bony insertion of the inferior oblique muscle may be detached without consequences, and the con-junctival incision extended upwards, laterally to the caruncle. A separate incision lateral to the caruncle (trans caruncular approach) can possibly be used to address the medical orbital wall when the floor is not to be removed. After this the medial orbital wall and the orbital floor are addressed as for orbital decompression through a coronal approach. With the transinferior fornix approach, however the wide exposure of the orbital floor permits an easy removal of the bony infraorbital canal and the floor lateral to it.
If more decompression is needed the lateral wall can be removed starting the osteotomy from the anterior portion of the inferior orbital fissure by means of bone nibbling rongeurs and by means of a surgical high-speed drill equipped with a cutting-burr or a diamond-burr tip. In order to aid the removal of the upper part of the lateral orbital wall and in particular its anterior superior portion, a lateral canthotomy and lysing of the inferior limb of the lateral canthal tendon can be performed converting, infact, the pure transinferior fornix approach into a swinging eyelid approach. An upper skin crease incision can also be used in combination with the pure inferior fornix or with the swinging eyelid approach if a wider exposure of the lateral orbital wall is to be attained.
The removal of the lateral orbital wall can be carried out up to the dura as described for the coronal approach and as for coronal approach at the end of the procedure the periorbita is incised in order to promote maximal prolapse of the orbital tissues into the newly created spaces. The canthotomy is closed in layers as for a regular canthopexy procedure, the upper lid crease incision only needs approximation of the skin edges while the inferior fornix incision does not need any suturing. Transinferior fornix, swinging eyelid, trans caruncular, and upper skin crease approaches can all be used to remove orbital fat too.
Correction of Lid Retraction in Graves Orbitopathy
In GO, upper and lower lid retraction are due to a combination of inflammation, fibrosis, adrenergic stimulation and restriction of vertical recti muscles. Exophthalmos also contributes in increasing the eyelid aperture by displacing either the upper or the lower lid. Recently the influence of decompressive surgery which leaves the lower lid retractors undisturbed has been reported to similarly contribute to the reduction of upper and lower lid displacemen. Correction of upper or lower lid retraction implies recession of the lid retractors. Spacers are not essential for upper lid lengthening procedures or for the treatment of mild degrees of lower lid retraction that can benefit from free recession of lower lid retractors and lateral canthoplasty.
The surgical correction of more severe forms of lower lid retraction requires interposition of spacer grafts between the tarsus and the recessed retractors to provide height and the necessary stiffness to support the lower lid against gravity. A number of autologous, homologous, xenogenic and synthetic materials have been used but the optimum spacer remains controversial. Among biological materials, ethanol preserved donor sclera has been widely used, but it is of limited availability, carries a risk of transmission of infections and it is associated with recurrent retraction due to graft absorption and fibrosis. Upper lid tarsus is an optimal material but its use is limited by the scarce possibility of harvesting at the donor site.
The stiffness of cartilage grafts may alter eyelid contour and adversely interfere with eyelid motility and down-gaze, the same applies to porous polyethylene sheets. Other synthetic materials such as polytetrafluoroethylene or polyester mesh carry the risk of extrusion. An autogenous hard palate mucosal graft is relatively easy to obtain, is similar to lower lid tarsus in terms of contour, thickness and stiffness, has a mucosal surface, has no risk of rejection and undergoes minimal shrinkage following grafting. Ophthalmic complications of hard palate mucosal grafting are uncommon and usually limited to transient corneal abrasion; morbidity at the donor site encompasses secondary haemorrhages, retarded healing due to oral infections, pain, and rarely oronasal fistula.
Homologous acellular dermal matrix is a processed donor tissue with appropriate consistency for posterior lamella augmentation. One surface is cut through the dermis, the other has an intact basement membrane which provides a structural template that guides conjunctival epithelial migration and repopulation. Homologous acellular dermal matrix represents a valid alternative to hard palate mucosal graft, its use reduces surgical time and eliminates the problem of donor site morbidity, but currently is not available in Europe.
In short, at present, hard palate mucosal graft providing structural and epithelial elements represents the best choice for posterior lamella augmentation in lower lid lengthening, although it may be associated with the disadvantage of not negligible donor site morbidity. In light of this and considering that donor site morbidity may be minimised by meticulous surgical technique and appropriate postoperative care, harvesting and implantation techniques will be given and commented below.
The treatment of persistent upper eyelid retraction is surgical and by far less predictable than that of lower lid. The medical therapy of upper lid retraction with a-blockers eye drops is scantly effective and topical or systemic therapy with post-ganglial adrenergic blocker drugs such as guanethidine is connected with several undesirable side effects. Botulinum toxin can also be an option, its effect however is limited in time and multiple injections are required. With botulinum toxin temporary under or over correction can occur. Deficit of elevation and paralysis of the orbicularis muscle may also be possible, undesirable complications in GO patients who are at risk for corneal exposure.
Considering that upper eyelid lengthening is one of the last steps of the long-lasting and somewhat exhausting surgical rehabilitation of patients with GO and that, although several surgical techniques for its cure have been proposed, an elective method is lacking, it is strongly advisable to use the quickest and simplest possible technique.
In keeping with this, a quick, systematic approach suitable for every degree of upper eyelid retraction with or without alteration of eyelid contour such as lateral or medial peaks is given in table 3 and the related surgical techniques will be described and commented below.
Lower Lid Lengthening Surgical Procedure
Hard Palate Mucosal Graft Harvesting
Prior to surgery a careful in office inspection of the donor site is mandatory for a correct selection of candidates, and at surgery the location of the donor site is fundamental in order not to bare the periosteum or being obliged to apply excessive diathermy as this may cause bone necrosis. Prior to surgery, any lesion suspected for malignancy should be biopsied; oral candidiasis in immunocom promised patients should be cured since postoperative granulation at the donor site can be delayed; the presence of exostosis such as torus palatinus or prominent palatal roots of teeth should be considered since the thin overlying mucosa of these areas may lead to unwanted periosteal or root damage at surgery.
The presence of a bifid uvula or a muscular diastasis of the soft palate can be an important clue to an underlying bony palatal cleft that is not otherwise evident and which represents an absolute contraindication for mucosal harvesting. However, the presence of small isolated clefts of the bony palate may escape clinical detection due to the presence of an overlying intact mucosa and to their asymptomatic nature. Besides iatrogenic damage to the bone and periosteum and infectious causes, fistulas may also develop from such a malformation.
At surgery the donor site should be placed between the median raphe and the alveolar process and not extended posteriorly behind the first molar. At this level the submucosa is well defined and partial thickness mucosal dissection can be easily carried out anteriorly to the neurovascular bundle emerging from the greater palatine foramen. The latter can in fact be located medially to the third or to the second molar. Areas close to the gingival border or to the median raphe are not suitable as donor sites since the risk of bone necrosis secondary to periosteal damage is much higher here: at these levels the mucosa is in fact directly attached to the periosteum without interposition of the submucosa.
Although hard palate mucosal grafts can be harvested under local anaesthesia, general anaesthesia is to be preferred for the patient's comfort. The mouth is open with a Jonson mouth spreader. The hard palate is dried and a dermographic pen is used to mark the graft size that should be about twice the degree of lower lid retraction in width. Submucosal infiltration with lidocaine 2% with epineph-rine 1:80,000 is then carried out to aid haemostasis and dissection.
The harvesting is carried out first using a No. 15 Bard-Parker blade to incise the marked area, then with a disposable angled keratotome and surgical forceps to dissect the submucosal plane and elevate the graft. The use of suction and of a tongue depressor by the surgical assistant will greatly aid in this phase. Excessive diathermy should be avoided at all times, and at the end of surgery, in order to control oozing at the donor site a rolled vaseline or haemostatic gauze can be inserted into the mucosal defect and kept in place with a previously prepared palatal shell, digital pressure on the shell can also be applied for some time and fibrin glue used if necessary. Bleeding from major vessels can be controlled with injections of local anaesthetic within the bleeding area or into the palatine foramen or with ligation if necessary.
The mucosa of the graft consisting of epithelium and thick collagenous lamina propria is then prepared for the recipient site by removing the fatty submucosa.
Large spectrum systemic antibiotics and antiseptic mouthwashes are recommended for 1 week after surgery. Soreness at the donor site for a few days after surgery is common especially during eating; custom-made acrylic palatal stents which aids haemostasis and favourite granulation can increase the patient's comfort.
Lower Lid Lengthening
Topical oxybuprocaine HC1 0.4% drops are applied to eye, then 0.5-1 ml of lidocaine 2% with epinephrine 1:80,000 is administered subconjunctivally along the inferior margin of the tarsal plate and 0.25 ml of the same anaesthetic is administrated subcutaneously into the centre of the lower lid. A 5-0 silk traction suture is placed in the centre of the lower lid along the eyelid margin and the eyelid is everted over a Desmarres retractor. An infratarsal incision is done for the whole length of the tarsal plate with a No. 15 Bard-Parker blade and the conjunctiva lower lid retractor complex transsected en bloc.
A preseptal plane is then bluntly developed in order to adequately recess the lower lid retractors and conjunctiva. Bleeding is easily controlled with bipolar diathermy. After this a 6.0 absorbable suture is used to suture the hard palate mucosal graft into place, between the border of the conjunctiva lower lid retractors complex and the inferior border of the tarsal plate, the mucosal surface facing the eyeball. Multiple steri-strips are applied on the lid skin in order to immobilize lid and graft in a correct position for a few days after surgery. No bandage is applied, but ice compresses are recommended for a few hours after surgery. Artificial tears are also prescribed to implement patient's comfort.
Upper Lid Lengthening
Sutureless Transconjunctival Müllerectomy Topical oxybuprocaine HC1 0.4% drops are applied to the eye, then 0.25 ml of lidocaine 2% with epinephrine 1:80,000 is administered subcutaneously into the centre of the upper eyelid. A 5-0 silk traction suture is placed in the centre of the upper eyelid along the eyelid margin and the eyelid everted over a Desmarres retractor. Then 0.5 ml of lidocaine 2% with epinephrine 1:80,000 is injected close to the superior tarsal border subconjunctivally and between Müller's muscle and the levator aponeurosis over the whole length of the eyelid.
A high temperature battery-powered cautery is used to incise the conjunctiva along and just above the superior tarsal border. After this the conjunctiva is separated from Müller's muscle first with sharp then with blunt dissection. In this way the superior fornix is approached (fig. 7a). Müller's muscle is then grasped with fine-toothed forceps at the lateral aspect, the tension exerted with the Desmarres retractor is relieved, and a plane can easily be developed between Müller's muscle and the inferior surface of the levator aponeurosis by spreading the blade of blunt pointed straight scissors. The distal insertion of the muscle is gently cauterised, afterwards severed with scissors. The proximal insertion is then similarly addressed. At the end of the procedure the conjunctiva is not sutured.
Any possible lateral or medial alteration of the eyelid contour is treated by means of weakening the levator aponeurosis at the level of the peak. This is achieved by means of several small horizontal incisions which transform the aponeurosis under consideration in a kind of network increasing in fact its vertical length. At the end of the procedure the traction suture which was placed in the centre of the eyelid is removed. No bandage is applied but ice compresses are recommended for a few hours after surgery. Artificial tears are prescribed to implement the patient's comfort.
Sutureless transconjunctival Müllerectomy is an effective procedure for the cure of mild degree of upper eyelid retractions up to 2-3 mm. It does not interfere with the position of the skin crease since surgical dissection is carried out under the levator aponeurosis. It takes around lOmin/eyelid, reintervention for under- or overcorrection are rare and usually due to surgical mistakes as incomplete excision of Müller's muscle or damage to the aponeurosis of the levator muscle. Tear secretion may be reduced after Müllerectomy by the conjunctival approach. Nevertheless, the clinical risk of dry eye is low, and counterbalanced by the usually good functional and cosmetic results of the procedure.
Free En-Bloc Recession of Conjunctiva-Levator Complex by Anterior Approach (Blepharotomy)
This technique was developed by Leo Koornneef one of the most bright minded and talented surgeons in the field of orbit and ophthalmic plastic surgery of the 1980s and 1990s. Because of his untimely death he was unable to publish his idea, nevertheless he could present it at meetings and teach it to several of his fellows including myself.
Topical oxybuprocaine HC1 0.4% drops are applied to the eye, the skin crease is lined with a surgical skin marker. Then 0.5-1 ml of lidocaine 2%with epinephrine 1:80,000 is injected close to the superior tarsal border subcuta-neously and between the orbicularis muscle and levator aponeurosis over the whole length of the eyelid.
An incision is made along the line previously drawn at the level of the upper skin crease through the skin orbicularis layer using a No. 15 Bard Parker blade. Then further dissection is carried out with spring scissors in order to expose the levator aponeurosis and the orbital septum. The orbital septum is opened along the whole length of the eyelid. After this, an en bloc, full thickness levator aponeurosis-Müller's conjunctiva incision is carried out just above the upper border of the tarsal plate: the levator-conjunctiva complex is grasped with fine-toothed forceps in the central portion of the upper lid, and after a gentle localised cauterisation, spring scissors are used to start the incision as a buttonhole. Then the first incision is extended laterally and medially preceded by gentle cauterisation of the levator-conjunctival complex. If a lateral flare is present the deformity is corrected by means of a graded vertical cut through the levator-conjunctiva complex at the level of the lateral horn of the aponeurosis.
The desired degree of lengthening is checked, against gravity, by closing the skin with a temporary suture positioned in the centre of the lid and bringing the patient to a sitting position. At surgery, a couple of millimetres of over-correction are advisable at surgery in order to compensate for postoperative retraction. When the desired level is obtained, a careful inspection of the wound is carried out and any bleeding point cauterised. Finally, the blepharotomy is closed by carefully suturing the skin only, with a running interlocked 6-0 Dermalon suture which should stay in place for 1 week. No bandage is applied but ice compresses are recommended for a few hours after surgery.
Free En-Bloc Recession of Conjunctiva Levator Complex by Sutureless Posterior Approach
Topical oxybuprocaine HC10.4% drops are applied to the eye, then 0.25ml of lidocaine 2% with epinephrine 1:80.000 is administered subcutaneously into the centre of the upper eyelid. A 5-0 silk traction suture is placed in the centre of the upper eyelid along the eyelid margin and the eyelid everted over a Desmarres retractor. Then 0.5 ml of lidocaine 2%with epinephrine 1:80,000 is injected close to the superior tarsal border between levator aponeurosis and orbicularis muscle along the whole length of the eyelid. After a gentle localised cauterisation, spring scissors are used to start a buttonhole incision through the conjunctiva-levator complex in the central portion of the everted eyelid.
Through the buttonhole incision, by spreading the blades of blunt spring scissors, a plane is easily developed between the orbicularis muscle and the anterior surface of the levator aponeurosis. Then the buttonhole incision is extended laterally and medially; in order to minimize bleeding, gentle cauterisation of the conjunctiva-levator complex that is to be severed always goes before any extension of the incision. The incision is carried out just above the upper margin of the tarsal plate in bilateral cases or at a higher level in monolateral upper lid retraction. In this way, in monolateral cases, the skin insertion of the levator aponeurosis is left undisturbed, the skin crease does not rise after surgery and symmetry with the contralateral side is preserved.
The levator aponeurosis and orbital septum are bluntly separated from the orbicularis muscle in order to promote recession of the conjunctiva-levator complex. If a lateral flare is present, the deformity is addressed as for the anterior approach. Also with the posterior approach, eyelid level and contour are repeatedly checked, against gravity, by bringing the patient to a sitting position since when the desired lengthening is achieved. A couple of millimetres of overcorrection at surgery are again advisable in order to compensate for the expected postoperative retraction.
Before the end of the procedure a careful inspection of the wound is carried out and eventual bleeding point cauterised. Finally, the traction suture which was placed in the centre of the eyelid is removed. No bandage is applied but ice compresses are recommended for a few hours after surgery. Artificial tears are prescribed to implement the patient's comfort.
Free en-bloc resection of conjunctiva levator complex performed via an anterior or a sutureless posterior approach is an effective technique for the treatment of medium to severe degrees of upper lid retraction. The results are however not always predictable and reintervention may be necessary. Several intraoperative factors may affect the setting of the upper eyelid height, their consideration may aid in increasing success. Intravenous sedatives interfere with the alertness of the patient and with his collaboration in setting eyelid position, thus these drugs should be used only when it is strictly necessary.
Povidone iodine is an adrenergic-blocking agent. Preoperative irrigation of the conjunctival sac with this solution will result in a paralysis of Miiller's muscle and should therefore be avoided. Paralysis of levator and orbicularis muscle induced by local anaesthetic and the contraction of Miiller's muscle induced by local anaesthetics containing epinephrine are variables that may interfere with the position of the upper eyelid. These variables can be partially controlled if the dose of anaesthetic, its concentration of epinephrine, the sites and the pressure of injection are maintained constant. In order to include the effect of gravity on eyelid height, this should be set by bringing the patient to a sitting position.
The anterior approach may be more desirable to many surgeons since it is the more common technique for ptosis surgery. With this approach, particular attention should be paid to the suture of the skin in order to avoid the risk of postoperative fistulas. The posterior approach cannot be performed in extreme degrees of retraction in which the tarsus cannot be everted, but it is the elective treatment in dark skinned patients in which an unpleasant scar may result from an anterior approach.
A full-thickness incision of conjunctiva levator complex may easily create a flat eyelid contour, if dissection is carried out too far medially. Careful medial dissection also prevents possible nasal droops that are often difficult to be corrected. The graded incision of the lateral horn of the aponeurosis in the case of lateral flare should be vertical or rather parallel to the ductules of the lacrimal gland to avoid any damage to these structures.
In none of the three aforementioned techniques is the conjunctiva sutured at the end of surgery. This prevents possible suture related corneal erosions and leaves a natural drainage with reduction of postoperative ecchymosis. As previously mentioned, pressure bandages are not applied after surgery and no particular treatments except ice compresses and elevation of the head at sleeping time are required in the immediate postoperative period. In the case that after surgery the operated eyelid or a part of it begins to retract, the patient should be instructed to massage the lid downward while looking upward in order to maintain the eyelid at the physiological position. In the case of posterior approaches, vigorous massages may be started soon after surgery while in the case of anterior approach they must be delayed for at least 2 weeks, in order to avoid dehis cence of the surgical wound and possible fistulas.
Conclusions
GO is the commonest cause of exophthalmos and eyelid retraction. These two aesthetic and functional disabling conditions are amenable to effective surgical treatment. Relatively simple techniques can be used to correct eyelid retraction while more elaborated procedures are required to treat exophthalmos and any possible associated alteration of the ocular surface.
