Treatment of sixth nerve palsy in adults with combined botulinum toxin chemodenervation and surgery

A Review of Transposition Techniques for Treatment of Complete Abducens Nerve Palsy

Purpose:

To review various types of extraocular muscle transposition procedures for management of strabismus in sixth cranial nerve palsy with little lateral rectus (LR) muscle function, along with their pros and cons.

Methods:

We performed a comprehensive review of transposition procedures in sixth cranial nerve palsy, based on literature published anytime up to March 2021. A thorough search through PubMed and Cochrane databases was performed. All types of clinical studies on different transposition procedures in LR palsy, were included.

Results:

Eighty-six original articles in English, with full text or abstracts available, were included in the review, among which 16 are prospective studies, 48 retrospective, 3 review articles, 1 randomized clinical trial, 17 case reports, and 1 letter. Vertical rectus transposition has demonstrated promising results, especially in abduction improvement and expansion of binocular diplopia-free visual field, albeit the possible adverse effects such as anterior segment ischemia, especially in the presence of medial rectus contracture, and induced vertical deviation may become troublesome. Partial muscle transposition, single muscle transposition, and also transposition without tenotomy have all been introduced to reduce the risk of multiple muscle manipulation and ischemia. On the other hand, different adjustable transpositions are being utilized to manage concomitant or induced vertical deviations.

Conclusion:

Transposition procedures are highly effective in the treatment of esotropia caused by complete LR palsy. Various techniques for vertical muscle transposition have been proposed, with each of them having certain advantages and disadvantages.

A new application of modified Nishida muscle transposition procedure for medial rectus muscle transection following endoscopic sinus surgery without tenotomy or splitting muscles

The modified Nishida muscle transposition procedure, in which the one-third of the vertical rectus muscle bellies are sutured onto the sclera in the infero- and superotemporal quadrants without either tenotomy of the vertical rectus muscles or splitting of the vertical rectus muscle is an effective treatment for abducens nerve palsy. We report 2 cases of large-angle exotropia caused by medial rectus transection following the endoscopic sinus surgery treated using the modified Nishida procedure to transpose both vertical rectus muscles nasally, combined with lateral rectus muscle recession.

A Modified Surgical Technique to Treat Strabismus in Complete Sixth Nerve Palsy

Introduction

A lot of different techniques have been proposed in order to manage abduction limitation secondary to sixth nerve palsy; however, anterior segment ischemia remains a concern. The aim of this study was to evaluate the results of augmented vertical recti muscle transposition (VRT) with partial recession of medial rectus muscle (MR) for complete, chronic sixth nerve palsy, a new modified technique that could also minimize the risk for anterior segment ischemia (ASI).

Methods

In this nonrandomized 8-year (2009–2017) retrospective review, 20 patients with complete sixth nerve palsy and contracted MR were enrolled. All of them underwent augmented VRT and partial recession of the MR, following a new proposed surgical technique. Only the central part of the MR tendon and belly was recessed by 6.5 mm, leaving 1.5 mm of the upper pole and 1.5 mm of the lower pole of the muscle intact, preserving the circulation of two anterior ciliary arteries.

Results

Twenty patients with a mean age of 43 years (range 12–71), all unilateral cases, were enrolled in this study. The mean preoperative deviation was 64.25 ± 10.9 prism diopters (PD) base out (range 50 to 90). In 17 cases (88%), the postoperative deviation was within 10 PD of orthotropia. Two patients (10%) had residual esotropia (15 PD and 20 PD, respectively), and one patient (5%) had 10 PD of hypotropia. The mean preoperative abduction limitation of −5.9 improved to −3.1 (p < 0.0001). None of the cases presented with ASI (success rate 100%).

Conclusion

Partial recession of the MR preserving the two anterior ciliary arteries (Kozeis modified technique) with augmented vertical recti muscle transposition is an effective procedure, with a high success rate and is probably less risky for ASI.

Anterior segment ischemia: etiology, assessment, and management

Anterior segment ischemia (ASI) is a potentially serious but rare complication of strabismus surgery. Among several risk factors, ASI occurs after strabismus surgery because of the nature of the anterior segment circulation. Disinsertion of rectus muscles leads to a decrease in the blood supply to the various anterior segment structures. We report a series of retrospective and prospective studies performed by our group focused on determining the risk of anterior segment ischemia following strabismus surgery, diagnosis, and modifications to surgical techniques to minimize the impact on anterior segment circulation. We found a significant decrease in postoperative anterior segment blood flow when operating vertical rectus muscles. Plication procedures preserve anterior segment circulation, and modifications to the technique allow the performance of adjustable sutures. Small adjustable selective procedures that spare the ciliary vessels have been demonstrated to be effective in patients with vertical and torsional diplopia. Ciliary sparing augmented adjustable transposition surgery decreases the risk of anterior segment ischemia while allowing management of potential post-operative alignment complications. Finally, ocular coherence tomography angiography is a valuable quantitative and qualitative technique to evaluate anterior segment ischemia. Strabismus surgeons should be aware of the risks of anterior segment ischemia when operating vertical rectus muscles. Modifications to standard surgical techniques allow surgeons to perform complex strabismus surgery in patients at risk for anterior segment ischemia.

Augmented vertical recti transposition with intraoperative botulinum toxin for complete and chronic sixth nerve palsy

PurposeTo evaluate the results of augmented vertical rectus muscle transposition (VRT) with intraoperative botulinum toxin (BTX) for complete and chronic sixth nerve palsy.MethodsDuring a 10-year period (2004-2014) all patients with chronic and complete sixth nerve palsy and contracted medial rectus (MR) who underwent augmented VRT and BTX injection into the MR enrolled in this study.ResultsIn total, 29 patients (5 bilateral) were enrolled in this study. Preoperative deviation was 45±17.5 Prism Diopter (PD), which was improved to -3.1±13.2 after the operation (P<0.001). Mean preoperative and postoperative abduction limitation was -4.4±1.1 and -1.8±0.9, respectively (P<0.001). The success rate was 76% (deviation within 10 PD of orthotropia). Four patients (13.7%) had hypotropia. In 19 patients with preoperative deviation ≤45 PD, four patients had consecutive exotropia.ConclusionIntraoperative BTX injection with augmented vertical rectus transposition is an effective procedure. In deviation ≤45 there is a risk of overcorrection.

Outcomes of three different vertical rectus muscle transposition procedures for complete abducens nerve palsy

PURPOSE

To compare the efficacy of three different vertical rectus muscle transposition (VRT) techniques performed as a sole procedure to correct ocular alignment and improve abduction in cases of complete abducens nerve palsy.

METHODS

The medical records of patients with complete abducens nerve palsy who underwent one of three different VRT procedures without simultaneous medial rectus weakening over a period of 20 years were retrospectively reviewed. The following procedures were used: full-tendon transposition (FTT), FTT with 4 mm resections before reinsertion (FTTR), and FTT with myopexy sutures (FTTM). We recorded the pre- and postoperative alignments, limitations of adduction and abduction, and complications. Follow-up was at least 6 months.

RESULTS

A total of 26 patients (age range, 8-74 years) were included: 25 unilateral and 1 bilateral. Follow-up ranged from 6 to 21 months. Among 25 patients having unilateral surgery, the mean changes in esotropia were: 36.0(Δ) for FTT (n = 9), 46.4(Δ) for FTTR (n = 7), and 41.3(Δ) for FTTM (n = 9). Mean improvements in abduction grading were 0.94 for FTT (9 eyes), 1.64 for FTTR (7 eyes), and 1.41 for FTTM (11 eyes). For both measures the means were not significantly different. Three patients (2 FTT and 1 FTTM) had new postoperative vertical tropias >3(Δ). Only 1 patient (with FTTR) had an overcorrection.

CONCLUSIONS

FTTR corrected the most esotropia and improved abduction to the greatest degree, with the advantages of a low risk of creating a new vertical deviation and avoiding the risks of extra scleral sutures.

Adjustable augmented rectus muscle transposition surgery with or without ciliary vessel sparing for abduction deficiencies

BACKGROUND

Vertical rectus transposition (VRT) is useful in abduction deficiencies. Posterior fixation sutures enhance the effect of VRT, but usually preclude the use of adjustable sutures. Augmentation of VRT by resection of the transposed muscles allows for an adjustable technique that can reduce induced vertical deviations and overcorrections.

METHODS

We retrospectively reviewed the records of all patients undergoing adjustable partial or full tendon VRT augmented by resection of the transposed muscles. Ciliary vessels were preserved in most of the patients by either splitting the transposed muscle or by dragging the transposed muscle without disrupting the muscle insertion.

RESULTS

Seven patients with abducens palsy and one with esotropic Duane syndrome were included. Both vertical rectus muscles were symmetrically resected by 3-5 mm. Preoperative central gaze esotropia of 30.6 ± 12.9Δ (range, 17-50Δ) decreased to 10.6 ± 8.8Δ (range, 0-25Δ) at the final visit (p = 0.003). Three patients required postoperative adjustment by recession of one of the transposed muscles due to an induced vertical deviation (mean 9.3Δ reduced to 0Δ), coupled with overcorrection (mean exotropia 11.3Δ reduced to 0 in two patients and exophoria 2Δ in one patient). At the final follow-up visit 3.8 ± 2.6 months postoperatively, one patient had a vertical deviation <4Δ, and none had overcorrection or anterior segment ischemia. Three patients required further surgery for recurrent esotropia.

CONCLUSIONS

Augmentation of VRT by resection of the transposed muscles can be performed with adjustable sutures and vessel-sparing technique. This allows for postoperative control of overcorrections and induced vertical deviations as well as less risk of anterior segment ischemia.

Vertical muscle transposition augmented with lateral fixation (Foster) suture for Duane syndrome and sixth nerve palsy

PURPOSE

To report the postoperative results of full-tendon vertical rectus transposition (VRT) augmented with lateral fixation suture for the treatment of type 1 Duane syndrome and sixth nerve palsy and to determine whether there was a decrease in the effect of the Foster suture over time.

METHODS

This retrospective, consecutive case series included patients who underwent a full-tendon VRT transposition with lateral fixation for type 1 Duane syndrome or sixth nerve palsy. The primary outcome measures included deviation, abnormal head posture(AHP), abduction deficiency, and postoperative binocular single visual field (BSVF).

RESULTS

Eighty-seven patients (87 eyes: 40 eyes with Duane syndrome and 47 eyes with sixth nerve palsy) were included in this study. In Duane syndrome patients, the deviation was reduced by a mean of 95%, the AHP was eliminated in 86% of patients, the abduction was improved by 42%, and a useful BSVF of ≈ 67% of normal was achieved at 1 year post operation. In sixth nerve palsy patients, the deviation was reduced by 99%, the abduction was improved by 59%, and a useful BSVF of ≈ 71% of normal was achieved at 1 year post operation. In both groups, the improvements in deviation angle and abduction were stable postoperatively. Sixteen patients needed reoperation for undercorrection.

CONCLUSION

VRT surgery with posterior fixation is an effective treatment method for complete sixth nerve palsy and Duane syndrome with esotropia, AHP, and abduction deficiency. The procedure carries a small risk of reoperation for undercorrection. The effect of the Foster suture did not decline over time.

Inferior oblique transposition for large hypertropia after vertical rectus transposition

Consecutive vertical deviations occur in 13% to 30% of cases after full tendon vertical rectus transposition (VRT) surgery in adult patients with abducens nerve palsy. We report a 7-year-old boy with congenital abducens nerve palsy who developed a large hypertropia following VRT with posterior fixation sutures. During subsequent surgery, extensive scarring of the vertical rectus muscles was observed, and an inferior oblique nasal anterior transposition was performed. The patient was orthotropic in primary position through 18 months of follow-up. The causes and management options for vertical deviation following VRT are discussed.

Adjustable suture technique for enhanced transposition surgery for extraocular muscles

PURPOSE

To evaluate the results of 2 methods of vertical rectus muscle transposition surgery for sixth (abducens) nerve palsy.

METHODS

Retrospective, comparative case series. Historically at our institution, transposed vertical rectus muscles were adjusted toward or attached at the adjacent corners of the lateral rectus muscle ("conventional transposition") before the development of a technique in which adjustable sutures are passed beneath the lateral rectus muscle to attach at its opposite corners ("crossed-adjustable transposition"). Comparative outcomes with these 2 techniques were analyzed in a consecutive series of sixth nerve palsy patients.

RESULTS

The change from preoperative to postoperative deviation at distance was 39.3(Δ) ± 22.7(Δ) in 23 conventional transposition cases and 48.5(Δ) ± 27.8(Δ) in 19 crossed-adjustable transposition cases, which demonstrated no statistically significant difference (p = 0.24, t-test). Simultaneous medial rectus weakening was needed less in the crossed-adjustable transposition group (37%) than in the conventional transposition group (83%), and this difference was statistically significant. (p = 0.004, Fisher exact test).

CONCLUSIONS

Adjustable vertical rectus muscle transposition surgery for the management of chronic sixth nerve palsy, enhanced by passing the adjustable sutures beneath the lateral rectus muscle, requires simultaneous medial rectus muscle weakening less than half as often for satisfactory results.

Unaugmented Vertical Muscle Transposition Surgery for Chronic Sixth Nerve Paralysis

INTRODUCTION

Chronic sixth nerve palsy can cause incapacitating diplopia requiring vertical muscle transposition surgery. Augmentation of surgery, with lateral fixation sutures, medial rectus recession or botulinum toxin injection, is associated with an increased risk of complications.

PURPOSE

Our aim was to evaluate the efficacy and safety of unaugmented full-tendon vertical rectus transposition in chronic sixth nerve paralysis.

METHODS

Longitudinal study of 21 patients with chronic sixth nerve paralysis of longer than 6 months duration, who underwent superior and inferior recti transposition surgery without medial rectus recession or botulinum toxin injection. Details of surgery, preoperative and postoperative examinations including full orthoptic examination were obtained from an electronic database. Outcomes included the change in angle of deviation, the requirement for further surgery to the medial rectus and postoperative improvement in diplopia. SPSS software (Version 12.0.1, SPSS Inc. Chicago, IL) was used to summarize baseline characteristics and outcomes and to compare preoperative and postoperative deviation (paired t-test).

RESULTS

Twenty-one patients (10 (47.6%) men and 11 (52.4%) women) with a mean age of 41 years (range 4 to 74 years) were operated in the period between April 1998 and November 2000. Eighteen patients had unilateral and three had bilateral acquired sixth nerve palsy. Nineteen patients required unilateral surgery and two had bilateral transposition procedures. In patients with unilateral sixth nerve palsy, mean esotropia in primary position before surgery was 46.7 prism-diopters (PD) (95% CI 35.9-57.4 PD) and improved to 14.6 PD after surgery (95% CI 6.4-22.7 PD). The angle of deviation was significantly reduced by an average of 32.1 PD (p < 0.001, paired t-test; 95% CI 22.6-41.6 PD). Over all, 10 patients (55.6%) had a well-controlled esophoria with a postoperative alignment of within 10 PD of orthophoria without diplopia in the primary position, for distance and near. A further six patients (28.6%) required additional medial rectus recessions to achieve success. The only complication observed was slippage of the inferior rectus in one patient (4.2%), who consequently required further surgery.

CONCLUSION

Botulinum toxin infiltration of the medial rectus in vertical rectus transposition surgery may be unnecessary, incurring cost, additional attendances and interventions for patients. Less than a third of all patients in our series required additional medial rectus recession later.

Management of vertical deviations after vertical rectus transposition surgery

PURPOSE

To describe options for the management of vertical deviations after vertical rectus muscle transposition surgery (VRT).

METHODS

Retrospective case series including 7 children who underwent VRT for esotropic Duane syndrome and developed the complication of a vertical deviation.

RESULTS

Eighty-two consecutive children underwent VRT for Duane syndrome. Seven eyes of 7 patients (4 boys, 3 girls) were found to have induced vertical deviations postoperatively. Average length of follow-up was 12.7 months (range, 3-28 months). Median induced vertical deviation was 10.1(Delta) (range, 8-12). All patients required only one additional surgery to ameliorate the vertical deviation. At final follow-up, the mean vertical tropic deviation was 0. Six patients were operated on within 4 days of VRT. Surgical strategies included recession of one vertical rectus muscle and repositioning of a posterior fixation suture.

CONCLUSIONS

In children undergoing VRT for esotropic Duane syndrome, the complication of a vertical deviation occurred in 8.5% of cases. The vertical deviation was completely ameliorated in each case by one surgical procedure involving recession of one of the transposed muscles.

General principles in the surgical treatment of paralytic strabismus

The surgical approach necessary to achieve the largest field of usable single binocular vision in patients with paralytic strabismus is one that has a greater effect in some directions of gaze than in others. Developing the appropriate "incomitant" strabismus surgery can be achieved by improving the ocular rotation of the involved eye(s), creating a matching rotation defect in the "normal" eye, and anticipating that surgery may create a new/different deviation (not present before the surgery) that can be used to surgeons' advantage. The severity of the limitation in ocular rotation will determine the amount and type of strengthening or weakening that will be necessary to the paralytic muscle and its yoke muscle.

Botulinum toxin and the eye

Botulinum toxin in ophthalmology is used to reduce the function of the eyelid muscles in spasms or therapeutically. Therapeutic and diagnostic use in strabismus is also discussed, along with the controversial treatment of nystagmus.

Long-term outcomes after surgical management of chronic sixth nerve palsy

BACKGROUND

In a multicenter prospective data collection study of chronic sixth cranial nerve palsy, we previously reported that the initial successful outcome rate was 39% after a single surgical intervention and 25% after surgery combined with botulinum toxin (Botox), using strict success criteria. We now report the longer term outcome of these patients.

METHODS

A previously described cohort of 31 patients in 18 centers who underwent strabismus surgery for a sixth nerve palsy of greater that 6 months duration was studied prospectively. Twenty-three had strabismus surgery alone and 8 surgery with Botox. Fourteen (45%) were complete palsies and 17 (55%) were incomplete. Seven (23%) were bilateral and 24 (77%) were unilateral. Outcome was classified at time of last follow-up, which was 5 weeks to 24 months postoperatively. Success was defined as no diplopia in primary position at distance fixation. Partial success was defined as no more than 10 PD esotropia despite diplopia.

RESULTS

Overall, 16 (52%) of the patients were classified as successes, 7 (23%) as partial successes, and 8 (25%) as failures. Three (43%) of the partial successes were using prism. Eight (35%) of the patients classified as successes or partial successes required 2 surgical procedures. Of all patients (10, 32%) who had a second surgery, only 2 (20%) remained failures.

CONCLUSIONS

Despite our reported poor initial surgical success rate in chronic sixth nerve palsy, additional strabismus surgery, longer follow-up, and the use of prism or face turn for small residual deviations yields an overall surgical success rate of 75%. More than 1 surgical procedure and prism are often necessary in the management of chronic sixth nerve palsy.

Initial treatment outcomes in chronic sixth nerve palsy

INTRODUCTION

We conducted a prospective multi-center, nonrandomized, data-collection study of patients with chronic sixth cranial nerve palsy. We evaluated success rates with conservative nonsurgical management, botulinum toxin (botox) treatment, strabismus surgery, and a combination of botox treatment and surgery.

METHODS

All members of the American Association for Pediatric Ophthalmology and Strabismus and the North American Neuro-Ophthalmology Society were invited to enroll patients with sixth nerve palsy or paresis of more than 6 months duration over a 2-year period (between March 1998 and February 2000). The botox and surgical groups received intervention within 3 months of enrollment. Success at 6 months from enrollment was defined as absence of diplopia in primary position and no more than 10 prism diopters (pd) distance esotropia in primary position. Patients with no follow-up were excluded.

RESULTS

Fifty-six eligible patients were enrolled by 33 investigators. Eighteen (32%) were traumatic in etiology, 15 (27%) were unknown (including presumed hypertensive), 14 (25%) were neoplastic, 2 (4%) were diabetic, and 7 (13%) were other. Twenty (35%) were managed conservatively without surgery, 10 (18%) with botox treatment, 19 (33%) with surgery, and 8 (14%) with a combination of botox treatment and surgery. Success at 6 months from enrollment was 15% in the conservatively managed cases, 10% with botox alone, 39% with surgery alone, and 25% with a combination of botox and surgery.

CONCLUSIONS

This study demonstrates that management of chronic sixth nerve palsy and paresis remains challenging. Spontaneous recovery occurs but is uncommon. Botox treatment alone was rarely successful, and a single surgical procedure had a lower-than-expected success rate. Care should be taken in directly comparing success rates between treatment groups because of bias in patient selection.

Vertical rectus muscle transposition and botulinum toxin for complete sixth nerve palsy

BACKGROUND

Effective surgical treatment of complete unrecovered sixth nerve palsy must include the transfer of abducting power to the temporal aspect of the globe with release of medial rectus contracture nasally. We describe our experience in the treatment of five such patients who underwent full vertical rectus transposition combined with botulinum toxin chemodenervation of the ipsilateral medial rectus muscle.

METHODS

The five patients all had primarily unilateral complete unrecovered sixth nerve palsy. They all underwent a complete preoperative and postoperative eye examination and an orthoptic assessment. Excursion into abduction was graded from -8 (globe immobilized in extreme adduction) to -4 (abduction as far as primary position) to 0 (full abduction). Abduction saccades and a forced muscle generation test confirmed the presence of complete unrecovered sixth nerve palsy, and forced duction testing measured the degree of medial rectus contracture. All patients received ipsilateral medial rectus injection of botulinum toxin in the preoperative (8 to 2 months before surgery) and perioperative periods, and underwent complete superior rectus-inferior rectus transposition temporally.

RESULTS

The average length of follow-up was 21 (range 6 to 48) months. The average preoperative distance alignment was 52 (range 25 to 80) prism dioptres (PD). Vertical rectus transposition combined with botulinum toxin injection resulted in an average distance alignment change of 66 PD (range 50 PD to 82 PD) of exoshift. The average final deviation was 1 PD of esotropia (range 4 PD of esotropia to 6 PD of exotropia). Average abduction improved from -6 (range -3 to -8) preoperatively to -1.7 (range -1 to -2) postoperatively. Saccades averaged -4 preoperatively and improved to -2 postoperatively. Normal vertical eye movements were preserved in all patients. A total field of single binocular vision was created in all patients, which averaged 55 degrees (range 30 degrees to 75 degrees) in the horizontal meridian. The field of single binocular vision from primary position into abduction averaged 23 degrees (range 18 degrees to 28 degrees).

INTERPRETATION

Temporal transposition of the vertical rectus muscles combined with perioperative botulinum toxin injection of the ipsilateral medial rectus muscle is a reliable and effective way of restoring functional binocular vision in patients with complete unrecovered sixth nerve palsy.

The role of drug treatment in children with strabismus and amblyopia

Strabismus, or misalignment of the eyes, is a common ophthalmic problem in childhood, affecting 2 to 5% of the preschool population. Amblyopia is an important cause of visual morbidity frequently associated with strabismus, and both conditions should be treated simultaneously. Pharmacological means for treating strabismus and amblyopia can be divided into 3 categories: paralytic agents (botulinum toxin) used directly on the extraocular muscles to affect eye movements; autonomic agents (atropine, miotics) used topically to manipulate the refractive status of the eye and thereby affect alignment, focus and amblyopia; and centrally acting agents, including levodopa and citicoline, which affect the central visual system abnormalities in amblyopia. Botulinum toxin, the paralytic agent that causes the clinical symptoms of botulism poisoning, can be injected in minute quantities to achieve controlled paralysis of the extraocular muscles. Although the role of botulinum toxin is established in adults with paralytic strabismus, its usefulness in the treatment of comitant childhood strabismus (primary esotropia and exotropia) is not universally accepted. Botulinum injections tend to be more effective with smaller degrees of strabismus, in patients with good binocular fusion, and in managing overcorrections or undercorrections after traditional muscle surgery. Inadvertent ptosis and paralysis of adjacent muscles, unpredictable responses and technical constraints of the injections limit its use in children. Miotic therapy, by altering the refractive state of the treated eye, offers an alternative to optical correction with bifocals in treating esotropia due to excessive accommodative convergence. It is also effective in treating residual esotropia following surgery. The ease of use of glasses restricts the wide application of miotics in these common strabismus syndromes. Atropine, an anticholinergic agent, paralyses the ability of the eye to focus or accommodate. In amblyopia therapy, atropine is used to blur vision in the non-amblyopic eye and offers a useful alternative to traditional occlusion therapy with patching, especially in older children who are not compliant with patching. The neurotransmitter precursor levodopa and the related compound citicoline have been demonstrated to improve vision in amblyopic eyes. The therapeutic role of these centrally acting agents in the clinical management of amblyopia remains unproven.

Surgical management of ocular motor cranial nerve palsies

This article reviews the various surgical treatment approaches currently used in the management of ocular motor cranial nerve palsies. Regardless of the approach, the final goal is improved alignment, especially in the primary and reading positions.

Botulinum toxin A treatment of overactive corrugator supercilii in thyroid eye disease

BACKGROUND/AIM

Patients with thyroid eye disease with upper eyelid retraction often develop overaction of the accessory muscles of eyelid closure, the glabellar muscles corrugator supercilii and procerus. The resultant glabellar furrowing (frown lines) contributes to the typical thyroid facies. The aim of this study was to evaluate the use of botulinum toxin A reversible chemodenervation of the glabellar muscles as adjunctive treatment in the rehabilitation of patients with thyroid eye disease.

METHODS

14 patients (13 females) ages 39-76 years (mean 52) with inactive thyroid eye disease and associated medial eyebrow ptosis and prominent glabellar frown lines were recruited. All patients had a history of upper eyelid retraction. Each patient was treated with a single botulinum toxin injection (Dysport 0.2 ml, 40 units) into each corrugator supercilii and sometimes procerus muscles as an outpatient procedure. The effectiveness and acceptability of the treatment was assessed clinically and from a patient questionnaire.

RESULTS

The injections were tolerated by 13/14 (93%) patients. There was resultant flattening of the glabellar region and improvement of medial eyebrow contour in all patients, with onset of paralysis within 1 week. All patients reported a subjective improvement in appearance. Side effects included one patient (7%) with reversible partial ptosis. The beneficial effect lasted 4-6 months, with a gradual return of function. Repeat treatment was indicated where there was persistent upper eyelid retraction and protractor overaction.

CONCLUSION

Botulinum toxin A chemodenervation of the glabellar muscles in these patients was effective and acceptable. Chemodenervation should be considered in the rehabilitation of patients with thyroid eye disease where there is upper eyelid retraction and overacting protractors resulting in a thyroid frown. Once the eyelid retraction has been successfully treated by surgery, the need for further glabella muscle chemodenervation is considerably reduced.

Dissociated effects of botulinum toxin chemodenervation on ocular deviation and saccade dynamics in chronic lateral rectus palsy

AIM

Changes in saccade velocity/amplitude characteristics (main sequence) and attenuation of distance esotropia in response to botulinum toxin (BTX-A) chemodenervation of the antagonist medial rectus were studied in a group of nine patients with chronic lateral rectus palsy.

METHODS

Serial measurements of ocular deviation and infrared oculograms of saccadic eye movements to targets at 5 degrees-20 degrees of lateral gaze were made before injection and at 2, 4, 8, 16, and 20 weeks after injection.

RESULTS

At 2 weeks after injection, the ocular deviation changed by a mean of 34.5 prism dioptres and the 5 degrees and 10 degrees adduction saccades were significantly slowed (p < 0.02 Wilcoxon signed rank test). By the second examination, however, the adducting saccade peak velocity had returned to normal while the mean ocular deviation remained significantly changed (p = 0.01 Wilcoxon matched pairs). By 20 weeks the mean ocular deviation was not significantly different from that before injection (p = 0.14 matched pairs).

CONCLUSIONS

The ocular realignment caused by BTX-A may persist after saccadic function has been restored. This may be because toxin may have a more profound and long lasting effect on the orbital singly innervated fibres which are active tonically at rest to hold gaze whereas there is relative sparing of the additional motor units recruited during fast eye movements.

Vertical muscle transposition augmented with lateral fixation

INTRODUCTION

Full vertical rectus muscle transpositions have been shown to be an effective treatment for lateral rectus palsies and type I Duane syndrome. This operation is usually accompanied by mechanical or botulinum toxin treatment of one or both medial rectus muscles. This series evaluates the effect of augmenting the transposed muscles with lateral fixation sutures.

METHODS

Transposition of the vertical rectus muscles to the lateral rectus muscle was performed in 23 eyes of 21 patients; transposition to the medial rectus muscle was performed in one eye of one of these 21 patients. A lateral fixation suture of 5-0 Dacron polyester filament was placed in the sclera 16 mm posterior to the limbus and adjacent to the lateral rectus muscle, incorporating one fourth of the transposed vertical rectus muscle. Of the 21 patients, five had type I Duane syndrome with a face turn and esotropia in the primary position, seven had a unilateral lateral rectus palsy, two had bilateral lateral rectus palsy, four had an ipsilateral lateral rectus palsy combined with a contralateral lateral rectus paresis (a recess resect procedure was performed on the paretic eye along with the augmented transposition on the paralyzed eye), two had gaze palsies, and one had a unilateral lateral rectus palsy with recurrent esotropia after a transposition procedure performed 16 years previously. Lateral fixation sutures alone were used in the last case listed. Postoperative diplopia-free fields were measured when possible (10 cases).

RESULTS

In most cases (19/23 eyes), alignment was achieved in the primary position with the use of the augmented transposition procedure alone. On average,20 degrees of binocular fusion into the abducted field was obtained. No postoperative limitation of adduction in the transposed eye was noted. Among the patients with Duane syndrome, 80% had elimination of the face turn; one patient had 5 degrees of residual face turn. The one patient with previous transposition surgery alone had an 80% (16 PD) reduction of the recurrent esotropia after placement of lateral fixation sutures. After augmented transpositions, induced vertical deviations in the primary position were uncommon (4/20 patients) and not greater than 2 PD. Significant lid fissure changes were not seen.

CONCLUSIONS

The addition of lateral fixation sutures to full vertical rectus muscle transpositions improves the tonic abducting force of the procedure for patients with lateral rectus palsy and type I Duane syndrome without compromising adduction.

Botulinum toxin in fourth nerve palsies

BACKGROUND

Botulinum toxin A (BTXA) has not been used routinely in the management of fourth nerve (IV N) palsy. However, it is known that the results of surgery can be unpredictable with a risk of over- or under-correction.

METHODS

The results were reviewed of 20 patients, aged 19-70 years, with unilateral and bilateral IV N palsies who received BTXA injections to the inferior oblique or inferior rectus muscles. The aetiology was congenital in 12 (60%), traumatic in six (30%), due to myasthenia in one (5%), and unclear in one (5%). Fifty per cent of patients had had previous strabismus surgery to a maximum of four procedures. The mean pre-injection vertical deviation was 11 prism dioptres. All but two patients had a single injection. Average follow-up was 19 months.

RESULTS

Ten patients (group I) received BTXA as a primary therapy. Following inferior oblique injection, six patients received little benefit and went on to surgery (83%) or continued with prisms (17%). Five patients from group I who had inferior rectus toxin were discharged symptom-free. Group 2 (10 patients) received BTXA for residual deviations postoperatively; in this group all except one patient with no fusion achieved long-term benefit following inferior rectus BTXA. In those who had inferior oblique injections, BTXA was useful in one patient (25%). Inferior rectus injection produced a greater chance of temporary reversal of the deviation.

CONCLUSIONS

BTXA is of greatest benefit in patients with residual deviations particularly when the inferior rectus is injected, but is of limited value as a primary therapy in chronic IV N palsy.

Anterior segment ischemia after strabismus surgery

Surgery on the extraocular muscles of the eye is generally consisted a safe procedure which is associated with low morbidity and mortality. While infrequent, intra-operative complications occasionally occur. Tenotomy of multiple rectus muscles can result in interruption of the vascular supply to the anterior segment of the eye. Anterior segment ischemia (ASI) may result. This article reviews the complication of anterior segment ischemia as a result of strabismus surgery and its potential for producing permanent visual loss.

Adjustable vertical rectus muscle transposition surgery

Transposition of the vertical rectus muscle to the insertion of a paralytic or aberrantly innervated lateral rectus muscle is useful in treating esotropia associated with abducens palsy and Duane syndrome. However, this procedure may cause a manifest vertical deviation, requiring either prismatic or additional surgical correction. In an attempt to reduce the incidence of this surgical complication, we performed vertical rectus muscle transposition surgery, using an adjustable suture technique on each muscle, in 10 consecutive patients with abnormal lateral rectus function. Preoperative diagnoses included abducens palsy (70%) and Duane syndrome (30%). Preoperative deviations ranged from 14 to 85 prism diopters esotropia (mean, 39 delta) in the primary position. No vertical deviation was present preoperatively. Following transposition surgery, 8 of 10 patients were esotropic, 1 of 10 patients was exotropic, and 4 of 10 patients had a manifest vertical deviation. At the time of adjustment, all vertical deviations were corrected by "recessing" the appropriate vertical rectus muscle. Additionally, exotropia was lessened by "recessing" both vertical muscles in one patient.

Improvement of compensatory head postures after strabismus surgery

PURPOSE

To determine the incidence and relative frequencies of orientations of compensatory head postures (CHP) and success in surgically treating the CHP seen in patients with pure lateral rectus paresis (group I), superior oblique paresis (group II), Duane syndrome (group III), Brown syndrome (group IV), and congenital motor nystagmus (group V).

METHODS

The authors retrospectively reviewed all patients assessed and treated between 1985 and 1991 with these five conditions. Frequencies and orientations of the CHP were determined in all patients in each group. The success of surgery in eliminating the CHP in the subgroups of patients who underwent surgery to treat the CHP also was determined.

RESULTS

The frequencies of CHP were 29.0% of 93 group I cases, 71.2% of 139 group II cases, 68.1% of 91 group III cases, 17.4% of 35 group IV cases, and all 23 group V cases, for an overall incidence of 56.7% of 381 patients. For patients who underwent surgery to eliminate a CHP, success rates were 85.7% of 21 group I cases, 75.6% of 41 group II cases, 87.2% of 47 group III cases, 100% of 5 group IV cases, and 78.3% of 23 group V patients, for an overall success rate of 82.5% of 137 surgical cases.

CONCLUSION

Because CHP is seen frequently in strabismus and nystagmus disorders, ocular causes must be ruled out in any case of an anomalous head posture. Appropriately planned surgery for CHP caused by incomitant strabismus or eccentric nystagmus null zones has a high rate of success in eliminating CHP.

Management of VIth nerve palsy--avoiding unnecessary surgery

Unresolved VIth nerve palsy that is not adequately controlled by an abnormal head posture or prisms can be very suitably treated by surgery. It is however essential to differentiate partially recovered palsies, which are amenable to horizontal rectus surgery, from unrecovered palsies, which must be treated initially by a vertical muscle transposition procedure. Botulinum toxin is a valuable tool in making this distinction. It also facilitates full tendon transposition in unrecovered palsies, which appears to produce the best functional outcome of all the transposition procedures, with a reduction in the need for further surgery. A study of the surgical management of 12 patients with partially recovered VIth nerve palsy and 59 patients with unrecovered palsy provides clear guidelines on how to attain a successful functional outcome with the minimum amount of surgery.

Recovery of anterior segment circulation after strabismus surgery in adult patients

The effects of vertical rectus muscle surgery on the anterior segment and iris fluorescein angiogram were documented in 43 eyes of 41 adult patients. Characteristic iris sector perfusion defects were seen in 33 of 37 eyes (89%) after primary vertical rectus muscle surgery (no previous surgery on these muscles). Although iris perfusion defects were commonly present, associated clinical signs were mild. Two patients developed permanent pupillary changes after simultaneous surgery on two rectus muscles (superior/inferior rectus muscles and contiguous inferior/medial rectus muscles). In most patients, clinical findings resolved and the iris circulation recovered during the first 2 weeks after surgery. In 3 of 8 patients with grade 3 anterior segment ischemia (pupil dysfunction and cells) or early "postoperative uveitis," recovery of iris circulation took up to 12 weeks. These findings indicate that the time course of recovery of the anterior segment circulation after vertical rectus muscle surgery may be shorter than previously assumed.

Modern management of sixth nerve palsy

Between November 1982 and September 1991, 179 patients with unilateral or bilateral sixth nerve palsy were treated in the Botulinum Toxin Strabismus Clinic at Moorfields Eye Hospital. Indications for treatment included prophylaxis (as part of a prospective treatment trial), maintenance therapy, diagnosis and adjunct to surgical therapy. A management plan for established sixth nerve palsy based on the rational use of toxin and surgery is suggested.

Botulinum A toxin (Oculinum) in ophthalmology

Botulinum A toxin has been used to treat strabismus and a variety of spasmodic neuromuscular diseases. Botulinum toxin treatment of strabismus is not as definitive and stable as the traditional surgical approach, but it has been found most useful in postoperative overcorrection, small deviations, sensory deviations, and acute sixth nerve palsy. This toxin has been effective in the treatment of essential blepharospasm and hemifacial spasm, for which it produces temporary relief of symptoms. In addition, this treatment has been applied to lower lid entropion, myokymia, aberrant regeneration of the seventh nerve, lid retraction, corneal exposure, nystagmus, spasmodic torticollis, and adductor spastic dysphonia.

Vertical rectus muscle transposition with intraoperative botulinum injection for treatment of chronic sixth nerve palsy

Six adult patients with acquired, chronic, complete sixth nerve palsy had vertical rectus muscle transposition to the lateral rectus muscle insertion with intraoperative injection of botulinum toxin into the ipsilateral medial rectus muscle. Five of six patients were orthophoric in primary gaze, and the remaining patient achieved single binocular vision with a small head turn. This method compares favorably with previously described transposition procedures for sixth nerve palsy in terms of amount of correction and size of the window of single binocular vision with a lower risk of anterior segment ischemia.

Incidence of inadvertent globe perforation during strabismus surgery

Visual loss following strabismus is rare and usually follows inadvertent perforation of the globe at the time of surgery. Previous studies have reported that the incidence of this complication occurs in 8% to 12.1% of patients undergoing conventional strabismus surgery, and higher incidences have been reported for posterior fixation sutures. We conducted a prospective study to determine the incidence of this complication in our patients. We identified one case of globe perforation in 67 patients (100 eyes). Twenty-two patients (44 eyes) had undergone previous strabismus surgery, and there was no evidence of previous scleral perforation in this group. We discuss the recent advances in strabismus surgery which may account for this difference in the incidence of scleral perforation.

Botulinum toxin therapy in dysthyroid strabismus

We report our experience with the use of Botulinum toxin injection in 38 patients (64 injections) with severe dysthyroid strabismus. Three quarters of the injections led to a decrease in the angle of the squint by a mean 75% of the initial deviation. The average duration of effect was two months. Twenty six patients went on to surgery after stabilisation of their squint and endocrine status. Six patients achieved a stable long-term result with Botulinum toxin only. We suggest these results of treatment of early dysthyroid myopathy are more consistent with the characteristics of inflammatory spasm than contracture. The value of Botulinum toxin as a temporary means of maintaining binocularity in these young patients is discussed.

The role of botulinum toxin in the management of sixth nerve palsy

Fifty-five patients with sixth nerve palsy have been treated with Botulinum toxin injection to the antagonist medial rectus, either in isolation or in combination with rectus muscle surgery. Forty of these patients (72 per cent) obtained significant benefit from injection at some stage in their management. Botulinum toxin has a major role in conjunction with transposition muscle surgery for the treatment of complete unrecovered sixth nerve palsy. In less severe paresis, a functional cure may be obtained in a significant number of cases with the use of Botulinum toxin alone, 37 per cent in this series. No serious complications were observed. In view of the safety of this procedure it is reasonable to consider an injection of Botulinum toxin in any adult patient with a persisting sixth nerve palsy.

The effects of strabismus surgery on anterior segment circulation

Anterior segment circulation was assessed in 35 adults one day after squint surgery by clinical observation and low-dose fluorescein iris angiography. Seventeen patients had primary vertical rectus muscle surgery and all showed angiographic evidence of ischaemia. No ischaemia was found in the 15 patients who had secondary vertical rectus muscle surgery, or any horizontal rectus muscle surgery. The staged group had intermediate findings between the above two. Age, dysthyroid eye disease and type of conjunctival incision did not correlate with fluorescein iris angiographic sector-filling delay on the first post-operative day. The time taken for the sector with delay to fill becomes less during the first two post-operative weeks. Redistribution of iris filling persists, however. This data suggest that the safe interval before further muscle surgery can be done is shorter than has previously been assumed. Since the anterior ciliary arteries do not reform into canals the probable mechanism of redistribution of blood flow is from the long posterior ciliary arteries and increased capacity of the collateral circulation.