Modified orbital decompression for dysthyroid orbitopathy

Comparison of degree of medial rectus muscle misalignment after medial orbital wall decompression with or without periosteal flap

PURPOSE

To compare the degree of postoperative medial rectus (MR) muscle misalignment in patients who underwent medial orbital wall decompression with or without a periosteal flap along the MR muscle.

METHODS

This retrospective, observational study included 40 sides from 26 patients. The following parameters were measured on axial computed tomographic images taken post- and/or preoperatively: the distance of the anteroposterior line between the posterior lacrimal crest and the junction of the ethmoid and sphenoid sinuses from the most medial point of the medial margin of the MR muscle; the angle created at the point of the MR globe insertion, the most medial point of the MR muscle, and the junction of the ethmoid and sphenoid sinuses; and the MR muscle cross-sectional area. Postoperative changes in the distance (MR muscle shift) and area (MR muscle expansion) were calculated, and MR muscle shift, MR muscle angle, and the rate of MR muscle expansion were compared between the groups with (22 sides) and without (18 sides) a periosteal flap.

RESULTS

MR muscle shift (P = 0.325), MR muscle angle (P = 0.219), and the rate of MR muscle expansion (P = 0.904) were not significantly different between the groups.

CONCLUSIONS

Preservation of the periosteum along the MR muscle is thought to prevent MR muscle misalignment after medial orbital wall decompression. However, the results of this study indicate that preservation of a periosteal flap may not contribute to lessening MR muscle shift after surgery.

Graded transantral orbital decompression outcomes in stable thyroid eye disease: a series of 47 orbits

Purpose: To provide outcome data for transantral orbital decompression for functional and aesthetic rehabilitation for exophthalmos in stable thyroid eye disease (TED).Methods: Retrospective, non-comparative chart review of consecutive TED patients who underwent primary-graded transantral orbital decompression for exophthalmos by a single surgeon (MAB) between 2005 and 2018. Additional inclusion criteria included follow-up >90 days and no prior orbital surgery. Outcome data collection included millimeters of proptosis reduction, postoperative complications, and patient satisfaction.Results: A total 30 patients (47 orbits) were included. Average reduction in proptosis: 2.8 mm (range 0-9 mm, median 2.5 mm). Post-operatively, new onset diplopia occurred in four patients, V2 numbness in 15 patients (17 orbits), and sinusitis in 2 patients (2 orbits). Phone surveys reached 9/30 patients (14 orbits): cosmetic improvement was reported in 14/14 orbits, relief of orbital ache reported in 10/10 orbits with pre-operative ache, relief of dry eye in 8/13 orbits with preoperative dry eye, and overall satisfaction score: 8.9/10 (range 4-10, median 10).Conclusions: Graded transantral orbital decompression is a viable option for stable TED patients with orbital ache, exophthalmos, and exposure keratopathy, resulting in a high degree of functional and cosmetic satisfaction in our cohort.

Postoperative Changes in Strabismus, Ductions, Exophthalmometry, and Eyelid Retraction After Orbital Decompression for Thyroid Orbitopathy

INTRODUCTION

Surgical rehabilitation of thyroid orbitopathy involves reducing proptosis, treating strabismus, lengthening the eyelids, and managing aesthetic changes. Not all are necessary in each patient; however, they often are. The current investigation intends to describe postdecompression changes that may influence the staging of these procedures.

METHODS

In this retrospective cohort study, records of 169 patients who underwent orbital decompression between 1983 and 2001 were reviewed. A single orbital specialist confirmed all measurements. Time to follow up was defined as the most recent follow up after decompression and prior to any secondary procedures. No strabismus or eyelid surgery was performed at the time of decompression. Strabismus was measured with alternating prism cover test. Ductions were estimated utilizing Hirschberg's method. Exophthalmometry was measured with Hertel. Eyelid positions were defined relative to the pupillary light reflex. Strabismus data were analyzed within eye pairs. Ductions, exophthalmometry and eyelid position were analyzed for each eye. T-test for paired data was utilized to compare means pre- and postoperatively.

RESULTS

The study population was on average 45 years old and 73.4% women. Average length of follow up was 1.2 years. Esotropia was significantly increased after decompression by an average of 8.1 prism diopters (p < 0.01). Exotropia and vertical deviations were not significantly altered. Ductions decreased by >5 degrees in at least one meridian for 68.1% of the population. Upper eyelid retraction remained unchanged; however, lower eyelid retraction improved by 50% from 1.4 mm to 0.7 mm (p < 0.01). Exophthalmometry improved from 23.5 mm to 19.7 mm (p < 0.01), and this result was correlated with the number of walls removed (Pearson r = -0.302, p < 0.01).

CONCLUSIONS

On average, esotropia and ductions tend to worsen with decompression surgery. This result supports the clinical dictum to avoid strabismus surgery until after decompression. The improvement in lower eyelid retraction suggests that at least lower eyelid-lengthening surgery should be reserved for after decompression, as there may be significant spontaneous improvement, while the same may not be true for upper eyelid retraction, which does not tend to change with decompression.

Orbital decompression for thyroid eye disease

The literature regarding orbital decompression for thyroid eye disease is vast, spanning multiple specialty areas including neurosurgery, head and neck, maxillofacial, and ophthalmic plastic surgery. Although techniques have advanced considerably over the more than 100 years during which this procedure has been performed, the 4 major approaches remain: transorbital, transcranial, transantral, and transnasal. The explosion in literature related to orbital decompression has mostly involved minor technical variations on broader surgical themes. The purpose of this review is to organize the major approaches in terms of bony anatomy and to contextualize variation in transdisciplinary techniques within a common conceptualization.

Endoscopical Orbital Fat Decompression with Medial Orbital Wall Decompression for Dysthyroid Optic Neuropathy

OBJECTIVE

To describe a novel approach to orbital decompression for dysthyroid optic neuropathy (DON).

METHODS

An augmented endoscopic transethmoid medial orbital wall decompression (ETMOWD) was performed on 43 consecutive patients (72 eyes) with DON in order to access the orbital apex adequately. Concurrently, endoscopic transethmoid fat decompression (ETFD) using a novel aspiration/cutting instrument to remove orbital fat was performed for further reduction of proptosis. All patients were followed up periodically for at least 6 months. Outcomes such as improvement of visual acuity (VA), color vision, degree of proptosis reduction as well as the incidence of surgical induced diplopia were analyzed at the final review.

RESULTS

Sixty-nine out of 72 eyes (95.8%) had a statistically significant improvement in VA from -0.65 ± 0.30 to -0.25 ± 0.22 postoperatively, with a mean improvement of 0.55 ± 0.17 (p < 0.001). Thirty-four out of 45 eyes had an improvement in color vision (p < 0.001). The range of proptosis reduction was 4 to 9 mm (mean 6.2 ± 1.2 mm). Postoperative symmetry was achieved to within 2 mm using an exophthalmometer in 39 of 43 patients (90.7%). Five patients developed diplopia in the postoperative phase, but had complete resolution within 3 months. Two patients had further deterioration in their diplopia following surgery.

CONCLUSION

Our technique of a combined ETFD with ETMOWD appears to be effective in managing patients with DON, with minimal morbidities and a low incidence of postoperative diplopia.

Iatrogenic diplopia [corrected]

Diplopia is a very disturbing condition that has been reported as a complication of several surgical procedures. The following review aims to identify the ocular and nonocular surgical techniques more often associated with this undesirable result. Diplopia is reported as an adverse outcome of some neurosurgical procedures, dental procedures, endoscopic paranasal sinus surgery, and several ophthalmic procedures. The most common patterns and some recommendations in order to prevent and treat this frustrating outcome are also given.

Graded decompression of orbital fat and wall in patients with Graves' orbitopathy

Purpose

To investigate the results of graded decompression of orbital fat and walls in Graves' orbitopathy (GO) considering the degree of proptosis reduction at surgery and preoperative computed tomography (CT) findings.

Methods

This is a retrospective interventional case series. Graded orbital fat and wall decompression was performed in 90 orbits of 55 patients. In patients with enlarged extraocular muscles and minimal orbital fat proliferation in preoperative CT scans, one- or two-wall decompression of posterior orbit was performed with minimal fat excision. In other cases, the maximal amount of fat tissue was removed from the post-septal area to the apex. If the proptosis was not satisfactorily symmetrically reduced at surgery, one- or two-wall decompression was performed successively. Symmetric reduction of proptosis was consistently confirmed intraoperatively to assure that a desired amount of exophthalmos reduction was achieved.

Results

Four types of decompression were performed: fat only (group 1), fat and one-wall (group 2), fat and two-wall (group 3), and two-wall and minimal fat decompression (group 4). The mean preoperative Hertel value (20.6 ± 2.8 mm) was reduced significantly at six months postoperatively (16.1 ± 2.3 mm). Proptosis significantly decreased with a mean of 4.3 ± 1.7 mm, and the reduction was greatest (5.1 ± 2.1 mm) in group 3. In group 1, a significant correlation between Hertel change and the volume of resected orbital fat was found (r = 0.479). Diplopia was newly developed or aggravated postoperatively in eight patients, and six of these patients were in group 3. With the exception of one patient, visual acuity improved to nearly normal postoperatively in all patients with optic neuropathy.

Conclusions

Graded orbital decompression of orbital fat and bony walls, as assessed by the degree of proptosis reduction during surgery, was effective and predictable with minimal complications in GO patients with vision-threatening or cosmetically disfiguring proptosis.

Surgical treatment of Graves' ophthalmopathy

The aims of surgical treatment in Graves's orbitopathy (GO) are improvement of function and appearance. Since antiinflammatory treatment of GO rarely results in a complete resolution of symptoms, surgical treatment is very important for patients well being. Rehabilitative surgery includes orbital decompression, squint correction, lid lengthening and blepharoplasty and these procedures have to be performed in centres of expertise. Various techniques have been developed for orbital decompression which allow now a graded approach to proptosis reduction and optic nerve decompression in emergency situations. Extraocular muscle recessions can be successfully performed to treat most of the patients with diplopia. Only large or complex squint angles are difficult to treat and step by step procedures are recommended in these patients. Lid lengthening procedures are performed most often in GO patients and should be performed under local anaesthesia to get a good result. Serious complications are rare.

Transcaruncular medial wall orbital decompression: an effective approach for patients with unilateral graves ophthalmopathy

Purpose. To evaluate the reduction in proptosis, incidence of postoperative diplopia, and postoperative globe symmetry after transcaruncular medial wall decompression in patients with unilateral Graves ophthalmopathy. Methods. Retrospective review of 16 consecutive patients who underwent unilateral transcaruncular medial wall orbital decompression from 1995 to 2007. The diagnosis of Graves ophthalmopathy was based on history and clinical findings including proptosis, lagophthalmos, lid retraction, motility restriction, and systemic thyroid dysfunction. Results. The mean reduction in proptosis was 2.3 mm. The mean difference in exophthalmometry preoperatively between the two eyes in each patient was 3.1 mm whereas postoperatively the mean difference was 1.1 mm (P = 0.0002). Eleven of 16 patients (69%) had 1 mm or less of asymmetry postoperatively. There was no statistically significant difference in the incidence of diplopia pre and postoperatively (P = 1.0). Conclusions. Medial wall orbital decompression is a safe and practical surgical approach for patients with unilateral Graves orbitopathy. The procedure carries a low risk of morbidity and yields anatomic retrusion of the globe that is comparable to other more invasive methods and may yield more symmetric postoperative results.

[Two-wall decompression without resection of the medial wall. Effect on squint angle]

BACKGROUND

Postoperative new onset diplopia can be a disadvantage for surgical orbital decompression in patients with exophthalmos in thyroid eye disease. The various modifications of decompression (number and combination of walls) differ in their influence on the postoperative squint angle. We report on postoperative diplopia in a modified 2 wall decompression strategy (lateral wall and floor).

METHODS

This study was a retrospective analysis of 36 consecutive 2-wall decompressions performed between 2006-2010 in 24 patients with 6 months of stable exophthalmos in thyroid eye disease after medical therapy and radiotherapy. The preoperative and postoperative squint angle in prism cover test (PCT), motility, induction of diplopia, reduction of exophthalmos, visual acuity and complications were evaluated.

RESULTS

In all 36 decompressions the postoperative squint angle was equal to or less than before surgery. In 8 eyes additional squint surgery was performed. The mean reduction in exopthalmos was 4.3 mm.

CONCLUSIONS

An adverse effect of decompression on the postoperative squint angle was not evident in this study. New induction of diplopia was not observed at all. One possible explanation is the preservation of the medial wall.

Diplopia and strabismus following ocular surgeries

Postoperative diplopia and strabismus may result from a variety of ocular surgical procedures. Common underlying mechanisms include sensory disturbance, scarring, direct extraocular muscle injury, myotoxicity from injections of local anesthesia or antibiotics, and malpositioning of extraocular muscles by implant materials. The most common patterns are vertical and horizontal motility disturbance. Treatment options include prisms, botulinum, occlusion, or surgery.

Transcaruncular orbital decompression: an alternate procedure for Graves ophthalmopathy with compressive optic neuropathy

PURPOSE

To study the efficacy of transcaruncular orbital apex decompression for Graves ophthalmopathy with compressive optic neuropathy nonresponsive to pulse corticosteroids.

DESIGN

Retrospective, interventional case series study.

METHODS

From August 1999 to November 2003, transcaruncular orbital decompression was performed in 22 consecutive Graves ophthalmopathy patients with compressive optic neuropathy refractory to pulse corticosteroids. The average period of corticosteroid treatment was 16.1 +/- 5.2 days. Main outcome measures were preoperative and postoperative best-corrected vision, Hertel exophthalmometry, 100-hue color sensation test, visual evoked potential, visual field, and new-onset diplopia.

RESULTS

Visual acuity improved significantly from 1.08 +/- 0.24 logarithm of minimal angle of resolution (logMAR) preoperatively to 0.29 +/- 0.18 logMAR postoperatively (P < .0001). Average improvement in retinal sensitivity was 9.4 +/- 8.2 dB, in P(100) value of visual evoked potential was 27.5 +/- 20.1, and in "total errors" of the 100-hue test was 309.9 +/- 214.3 after surgery. Average retroplacement effect was 3.7 +/- 1.6 mm. Statistical analysis showed significant differences between preoperative and postoperative measurements for all above parameters (P < .0001). New-onset diplopia occurred in 38% of patients. There were no complications specifically attributable to the transcaruncular technique.

CONCLUSIONS

The transcaruncular approach offers access to the medial and inferior wall for orbital apex decompression in Graves ophthalmopathy patients with compressive optic neuropathy refractory to pulse corticosteroids. Advantages over other approaches included no external scar, less damage to adjacent tissue, and wide exposure to the entire medial wall.

Coronal or swinging eyelid decompression for patients with disfiguring proptosis in Graves' orbitopathy? Comparison of results in one center

PURPOSE

To compare 2 different approaches for 3-wall orbital decompression in patients with disfiguring proptosis due to Graves' orbitopathy, and to determine which technique is preferable.

DESIGN

Retrospective nonrandomized study with a concurrent comparison group.

PARTICIPANTS

Charts of 74 consecutive patients with disfiguring proptosis due to Graves' orbitopathy who underwent coronal (46) or swinging eyelid (28) decompression between January 1, 2000 and January 1, 2004 were studied retrospectively. Patients with dysthyroid optic neuropathy were excluded.

METHODS

We analyzed the following parameters: proptosis reduction, ocular motility, number of additional operations, number and kind of complications, patients' satisfaction, patients' estimation of numbness or abnormal sensations in the field of operation and surgical scars, and duration of hospitalization time.

MAIN OUTCOME MEASURES

Reduction of proptosis, changes in eye motility, and duration of hospitalization.

RESULTS

Mean proptosis reductions were 4.8 mm (range, 1-11) after coronal decompression and 5.6 mm (range, 0-8) after swinging eyelid decompression (P = 0.025). Patients who were operated by the swinging eyelid approach had no more deteriorated motility and a shorter hospitalization time. Complications were seen rarely. Both groups of patients showed high satisfaction scores.

CONCLUSION

Relative to the coronal approach, swinging eyelid decompression results in at least the same proptosis reduction, no greater motility disturbance, and a shorter hospitalization time.

Efficacy and side effects of ‘swinging eyelid’ orbital decompression in Graves' orbitopathy: a proposal for standardized evaluation of diplopia

OBJECTIVES

To evaluate the efficacy and side effects of 'swinging eyelid' orbital decompression in patients with Graves' orbitopathy (GO). To calculate the incidence of postoperative new-onset diplopia (NOD) using a newly proposed scoring system for diplopia.

METHODS

We reviewed the clinical data on proptosis, visual acuity, and diplopia in 104 consecutive patients (198 orbits) with GO, who underwent orbital decompression. A combined lateral canthal and inferior fornix incision ('swinging eyelid' approach) was used for removal of the medial wall, the orbital floor and, if indicated, the lateral wall. Indications for surgery were disfiguring/congestive GO (DGO) in 79 patients (149 orbits) and compressive optic neuropathy (CON) in 25 patients (49 orbits). Diplopia was scored according to four grades. In both groups, the incidence of new-onset (continuous) diplopia (NOD), deterioration of diplopia (DOD), and improvement of diplopia (IOD) were calculated, using strictly defined criteria. Our data on NOD were compared to those from other series, after recalculation according to our criteria.

RESULTS

The mean proptosis reduction was 4.6 mm (range 0-9.5 mm) after three-wall decompression (95 patients, 180 orbits) vs 3.1 mm (range 0-7 mm) after two-wall decompression (nine patients, 18 orbits). The visual acuity improved in 98% of the patients with CON. In patients with DGO, NOD occurred in 14%. In patients with CON, NOD was not observed, but DOD occurred in 41%. Our data compare favourably to the reported incidence of NOD after either transantral or transnasal decompression.

CONCLUSIONS

"Swinging eyelid' orbital decompression is efficacious for proptosis reduction as well as for optic nerve decompression. A scoring system for standardized evaluation of diplopia is proposed.

Thyroid-associated orbitopathy: a clinicopathologic and therapeutic review

PURPOSE OF REVIEW

To review the literature related to thyroid-associated orbitopathy and to emphasize recent developments in its pathophysiology, diagnosis, and therapy. Current therapeutic trends and controversies are discussed.

RECENT FINDINGS

Expression of thyroid stimulating hormone receptor is highest in the fat and connective tissue of patients with thyroid-associated orbitopathy, where fibroblasts have the potential for adipogenesis. Electrophysiology can now detect subclinical optic neuropathy, and somatostatin-receptor scintigraphy can help justify immunomodulation. Other than steroids, radiotherapy can control inflammation, but its use is controversial. Current trends in orbital decompression are to camouflage incisions and to limit strabismus with balanced decompression, deep lateral wall techniques, fat removal, and onlay implants. Proptosis reductions of 0.9 to 12.5mm are possible by the use of various algorithms. Before or after decompression, botulinum toxin can correct strabismus, intraocular pressure elevation, and retraction. The latter is now also treated with full-thickness blepharotomy.

SUMMARY

As knowledge of the pathophysiology of thyroid-associated orbitopathy grows, there is a slow movement from nonspecific and invasive measures to more directed treatments causing less morbidity.

Techniques et indications chirurgicales des décompressions osseuses de l’orbitopathie dysthyroïdienne

Orbital bony decompression has a definite place in the management of severe manifestations of dysthyroid orbitopathy such as optic neuropathy, exposure keratitis, and exophthalmos. This surgical procedure can be undertaken when medication and radiation therapy fail. Esthetic and functional results are globally satisfying and explain the interest taken in this technique. This article will describe the development of this procedure and will outline the surgical techniques and their complications. It emphasizes the multifactor indications for this procedure.

Primary-gaze diplopia in patients with thyroid-related orbitopathy undergoing deep lateral orbital decompression with intraconal fat debulking: a retrospective analysis of treatment outcome

Our goal was to investigate the incidence of postoperative primary gaze diplopia in patients with thyroid-related orbitopathy (TRO) undergoing deep lateral wall orbital decompression surgery with intraconal fat debulking in the Jules Stein Eye Institute over a period of 4(1/4) years. Overall 201 orbital decompression surgeries were performed in 116 patients (23 males, 93 females). All surgeries were performed by two of the authors (R.A.G. and J.D.M.) and in the noninflammatory phase of the disease. Exophthalmos decreased by an average of 3.4 +/- 2.7 mm from 23.8 +/- 3.2 mm (17-31) to 20.4 +/- 2.5 mm (14-29), p < 0.001, 95% confidence interval (CI) (3.0:3.8). 31% of patients had preoperative primary gaze diplopia and 28.4% had postoperative primary gaze diplopia. Thirty (83%) of the 36 patients with preoperative diplopia had also postoperative diplopia; 6 (16.7%) of the 36 patients had improvement in diplopia following deep lateral wall decompression. Of the 80 (69%) of patients without preoperative double vision 3 developed postoperative double vision in primary gaze (2.6% of all patients). These 3 patients were older (56 versus 46 years, p = 0.047), had more limitation in ocular movements (p = 0.017) and achieved more decrease in proptosis with surgery (6 versus 3.1 mm, p = 0.024). No complications were associated with orbital decompression. In conclusion deep lateral wall orbital decompression surgery with intraconal fat debulking is associated with a low rate (2.6%) of new-onset primary gaze diplopia. Some patients (5.2%) with preoperative diplopia actually had improvement in diplopia postoperatively. This surgery is effective in reduction of congestion and exophthalmos, and is not associated with detrimental effects on visual acuity.

Transcaruncular Orbital Decompression for Dysthyroid Optic Neuropathy

PURPOSE

To determine the efficacy of transcaruncular approach orbital apex decompression for treatment of dysthyroid optic neuropathy.

METHODS

In this retrospective noncomparative interventional case series, charts for all patients undergoing orbital decompression surgery for dysthyroid optic neuropathy performed by one author between October 1999 and September 2001 were included in the study. Primary outcome measures included visual acuity, static perimetry, pupillary testing, and color plate testing before and after surgery. Records were also reviewed for changes in extraocular motility and proptosis after surgery and for surgical complications.

RESULTS

Sixteen consecutive patients (6 unilateral, 10 bilateral, for a total of 26 cases) underwent orbital apex decompression for dysthyroid optic neuropathy through a transcaruncular approach. In each orbit, the optic neuropathy was refractory to oral corticosteroid therapy. Preoperative visual acuity remained stable or improved in each case. Preoperative Humphrey visual field testing revealed an average mean deviation of -10.3 +/- 6.5 (range, +0.76 to -25.45). Average postoperative mean deviation was -2.79 +/- 2.4 (range, +0.94 to -9.82). Before surgery, 7 of 23 eyes (30%) had full color plates. After surgery, 22 of 23 eyes (96%) had full color plates. Follow-up ranged from 2 to 26 months (mean, 10 months). New-onset diplopia developed in 2 of 10 (20%) patients without preexisting diplopia.

CONCLUSIONS

Transcaruncular approach orbital apex decompression effectively treats dysthyroid optic neuropathy.

Medial and lateral orbital wall surgery for balanced decompression in thyroid eye disease

OBJECTIVES/HYPOTHESIS

Diplopia remains a major potential complication of orbital decompression performed for thyroid eye disease. We sought to examine the effect of medial and lateral wall surgery with sparing of the orbital floor on the incidence of postoperative diplopia.

STUDY DESIGN

Retrospective review.

METHODS

A retrospective review was made of 63 consecutive medial and lateral orbital wall surgeries (40 patients) performed between December 1996 and May 2002 for orbital decompression of thyroid eye disease.

RESULTS

The average patient age was 50.9 years of age (age range, 14-83 y). The studied group was predominantly female (sex ratio, 36:4). Indications were compressive optic neuropathy (34), exposure keratopathy (25), and aesthetic concerns (4). The mean time since surgery was 31.5 months (range, 3-69 mo). The medial wall was approached by a transcaruncular (59) or endoscopic (4) technique. Two patients had fat removal. The average improvement in exophthalmos was 4.1 mm (range, 0-10 mm). The average palpebral fissure improvement was 2.0 mm (range, 0-7 mm). Two patients had cerebrospinal fluid leaks during excavation of the sphenoid bone. These were diagnosed and repaired primarily without complication. New-onset diplopia occurred in four patients. Two of these patients required strabismus surgery.

CONCLUSION

A 10% new-onset diplopia rate compares favorably with other surgical series. Medial and lateral wall surgery only, sparing the floor, may reduce diplopia after surgery for orbital decompression in thyroid eye disease.

Reduction of diplopia following endoscopic orbital decompression: the orbital sling technique

OBJECTIVE

Although endoscopic orbital decompression has become the surgical treatment of choice for patients with proptosis from Graves disease, postoperative diplopia requiring corrective eye muscle surgery can occur in up to 63% of patients. The purpose of the study was to evaluate a new technique intended to reduce the incidence of diplopia following endoscopic orbital decompression.

STUDY DESIGN

Case-control.

METHODS

Endoscopic orbital decompression was performed on 58 orbits in 37 patients with proptosis from Graves disease. The orbital sling technique, which makes use of a horizontal strip of periorbital fascia to prevent prolapse of the medial rectus muscle, was used on 20 orbits in 13 patients. Conventional endoscopic decompression was performed in 24 control subjects. The mean duration of follow-up was 3.3 +/- 1.3 years (range, 1.7-5.1 y).

RESULTS

The incidence of new-onset or worsened diplopia following endoscopic decompression was significantly lower for the orbital sling group compared with control subjects (0% vs. 29.2%, respectively [ =.038]). No patients in the orbital sling group developed new-onset diplopia following surgery. Of the eight patients with pre-existing diplopia from the orbitopathy, double vision improved in four patients (50%) and was unchanged in the remaining four patients (50%). The mean reduction in proptosis was comparable for the orbital sling and control groups (5.1 +/- 1.1 mm vs. 5.0 +/- 1.9 mm, respectively [ P=.98]). CONCLUSIONS The preservation of a fascial sling overlying the medial rectus muscle during endoscopic orbital decompression appears to reduce the incidence of postoperative diplopia, while still allowing for a satisfactory reduction in proptosis. This modification of the standard decompression technique should be considered for the treatment of patients with proptosis.

Orbital decompression: current concepts

The orbit in Graves disease undergoes expansion in soft tissue content as a result of the infiltration of orbital fat, extraocular muscles, and the lacrimal gland. Compression of the intraorbital contents leads to disorders of the lid-corneal interface, keratopathy, motility disturbances, exophthalmos, and optic neuropathy. Orbital decompression has traditionally been reserved for those patients with unremitting optic neuropathy. This article provides a historical review of orbital decompression, as well as a review of the evolution of surgical approaches toward both soft tissue and bony decompression. Recent trends in surgical management include fat decompression, more extensive posterior sculpting of the lateral wall, and direct approaches to the medial wall. Preoperative predictors of diplopia and hypoglobus are addressed, as are the various techniques that are employed to limit new postoperative strabismus. The roles of endoscopy and combined surgical techniques are also reviewed. Expanded indications for decompression and its effect on increased intraocular pressure are discussed as well.

The inferomedial orbital strut: an anatomic and radiographic study

PURPOSE

To study the anatomic and radiographic features of the inferomedial orbital strut (IOS), with particular emphasis on the region of the posterior IOS.

METHODS

Cadaver dissection study of the IOS was performed on 20 orbits of 10 fresh-frozen cadaver specimens. Radiographic volumetric analysis was performed on CT scans of 20 orbits to measure the volume available for decompression in the region of the posterior IOS.

RESULTS

The anterior IOS provided bony support to the orbit and served as a site of attachment for globe-supporting suspensory ligaments. The midportion of the IOS demonstrated a contiguous anatomic relation to the maxillary sinus ostium. The posterior IOS consisted of two components: the intraorbital process of the palatine bone and ethmoidal air cells that extended inferior and posterior to the IOS. Radiographic volumetric analysis demonstrated that there was an average of 2.1 mL of volume available for decompression in the region of the posterior IOS (range, 1.2 to 3.3 mL).

CONCLUSIONS

The findings of this anatomic and radiographic study of the inferomedial orbital strut support the concept of a posterior inferomedial orbital decompression. The region of the posterior IOS appears to offer significant volume for axial globe mobilization while minimizing the risk of globe dystopia and/or impairment of the maxillary sinus drainage.

Graded orbital decompression based on severity of proptosis

OBJECTIVE

To study the results of orbital decompression based on the severity of preoperative proptosis.

DESIGN

A retrospective noncomparative interventional case series.

PARTICIPANTS

Thirty-nine orbits in 23 patients with thyroid-related orbitopathy at a university-based referral center.

INTERVENTION

Graded orbital decompression was performed in all patients based on the severity of preoperative exophthalmometry.

MAIN OUTCOME MEASURES

Exophthalmometry, visual acuity, margin-to-reflex distance, prism cover testing, and intraocular pressure.

RESULTS

Mean proptosis reduction in all orbits was 6.4 +/- 2.7 mm (P < 0.01). In group 1 (preoperative exophthalmometry <22 mm), proptosis decreased with a mean of 4.8 +/- 1.3 mm (P < 0.01); mean proptosis reduction was 6.0 +/- 2.3 mm (P < 0.01) and 8.9 +/- 3.4 mm (P < 0.01) in group 2 (exophthalmometry between 22-25 mm) and group 3 (exophthalmometry >25 mm), respectively. In four of five eyes with compressive optic neuropathy there was an improvement of best-corrected visual acuity of 2 lines or more. Margin-to-reflex distance of the upper and lower lids and intraocular pressure were reduced in all groups. New-onset diplopia developed in two patients (8.7%); 13 of 15 patients (86.7%) who had diplopia preoperatively had persistent diplopia postoperatively. Two patients (13.3%) had relief of diplopia postoperatively.

CONCLUSIONS

Graded orbital decompression based on the severity of preoperative exophthalmometry is useful to determine the type and amount of orbital surgery to be performed.