Anterior segment ischemia after strabismus surgery

Investigation of alterations in retrobulbar hemodynamics and their correlation with choroidal thickness after strabismus surgery

BACKGROUND

To evaluate the changes in retrobulbar circulation after strabismus surgery and to assess the relationship of these changes with choroidal thickness (CT).

METHODS

This prospective study included 26 eyes of 26 patients who underwent strabismus surgery and 15 eyes of 15 healthy individuals as control group. The patients who had single horizontal muscle surgery were included in Group 1 (n = 14); and those who had surgery on both horizontal muscles were included in Group 2 (n = 12). Peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) of ophthalmic artery (OA), posterior ciliary artery (PCA), and central retinal artery (CRA) were measured using Color Doppler Ultrasonography. Subfoveal CT was measured via Optical Coherence Tomography. All measurements were obtained preoperatively, at 1st week and 1st month after surgery.

RESULTS

There were no differences regarding preoperative blood flow velocity parameters among the groups. OA RI increased significantly at 1st week and 1st month after surgery in Group 1 and 2 (P = 0.029 and P = 0.045, respectively). There was a significant increase in PCA PSV at 1st week in Group 1 (P = 0.002). There was no difference between the mean preoperative and postoperative CT among the 3 groups. A negative correlation between the percentage changes of CT and CRA EDV was found in Group 2 (P = 0.011).

CONCLUSION

Single and double horizontal rectus muscle surgery have a measurable effect on retrobulbar hemodynamics but these changes do not correlate with CT.

Incidence, Risk Factors and Management of Postoperative Complications in Horizontal Strabismus Surgery

OBJECTIVE

To report the incidence, risk factors and management of postoperative complications after horizontal strabismus surgery.

DESIGN

Retrospective Cohort study.

PARTICIPANTS

The study assessed 1,273 patients with 1,035 cases of exotropia and 238 cases of esotropia, with a minimum 18-month follow-up.

METHODS

Retrospective review of strabismus operation patients' medical records included baseline demographics, age at surgery, pre/postoperative visual acuity, and deviation. Complications were categorized as surgical site (infection, scarring, cyst, granuloma, ischemia) and strabismus-related (recurrence, diplopia), with analysis of incidence, risk factors, and management.

RESULTS

Among surgical site complications, the incidence of infection, pyogenic granuloma, and anterior segment ischemia were similar between the exotropia (0.3%, 0.3%, 0.2%) and esotropia (0.8%, 0%, 0.4%) groups (p = .221, 0.406, 0.515). In contrast, the esotropia group presented a higher risk of conjunctival inclusion cyst and conjunctival scar than the exotropia group, with incidences of 5.0% vs 2.2% and 6.3% vs 1.3%, respectively (p = .004, <0.001). Regarding strabismus complications, the incidence of early recurrence was not significant between the two groups, with 10.0% in the exotropia group and 10.5% in the esotropia group (p = .553). Older age and poor initial visual acuity were associated with early recurrence (p < .001). The esotropia group had a higher risk of persistent diplopia than the exotropia group, with incidences of 4.2% vs 2.0%, respectively (p = .003).

CONCLUSION

Esotropia carries a higher risk of conjunctival inclusion cysts, conjunctival scarring, and persistent diplopia compared to the exotropia group, while both groups exhibit similar rates of early recurrence and other surgical site complications.

Management of traumatic globe subluxation with optic nerve and extraocular muscle transection

A care algorithm for partial globe subluxation cases with optic nerve and at least one extraocular muscle (EOM) transection is presented after a literature review was performed using key term variations of globe, ocular, subluxation, optic nerve evulsion or transection, and trauma. Partial globe subluxation cases with transection of the optic nerve and at least 1 EOM were included. Exclusion criteria included globe rupture, complete enucleation defined by a globe without at least 1 EOM attachment, or unclear details confirming optic nerve transection. Including the patient presented herein, a total of 24 patients with 26 eyes were analyzed. About 73.08% of cases underwent initial repositioning (n = 19), with 11.54% of those requiring secondary enucleation or evisceration (n = 3). Of the secondarily managed cases, 2 of the 3 cases listed pain (n = 2) and inadequate cosmesis (n = 1) as rationale. We found that 26.92% of cases underwent initial enucleation (n = 7), citing lack of visual potential and limiting later complications. Most cases favored repositioning, which was typically sustainable. Initial repositioning can improve cosmetic outcome and psychological impact. Given the low risk of later management, cases of traumatic partial subluxation with EOM and optic nerve transections should attempt initial repositioning.

Extraocular Rectus Muscle Stretching as a Weakening Procedure

INTRODUCTION

Anterior segment ischemia may occur when three or more rectus muscles are operated in the same eye. Our purpose was to investigate the efficacy of rectus muscle stretching as a vessel-sparing weakening technique, in comparison with a retrospectively collected series of patients.

METHODS

Non-operated patients with an indication of medial rectus muscle weakening surgery (deviation up to 20 PD, prism diopters) who could cooperate with topical or sub-Tenon's anesthesia. Clinical workup included routine complete ophthalmological evaluation. One double-needle 6/0 Mersilene suture was used on each side of the muscle at 4 mm distance of the insertion and pulled/stretched to insert in the sclera 3-5 mm posterior to the muscle locking passes. Main outcome measure was distance deviation at 2 months after surgery (alternate prism and cover test).

RESULTS

Seven patients with esotropia of 12-20 PD, recruited in a 20-month period, were included. Preoperative median deviation was 20 PD, whereas postoperative median deviation was 4 PD (range 0-8 PD). On a visual pain scale (1-10) median pain score was 3 (range 2-5). Remarkable postoperative complications did not occur. Significant differences with a retrospectively collected series of patients' data, treated with standard medial rectus recession, were not observed.

CONCLUSIONS

Preliminary data indicate that stretching of a rectus muscle has some weakening effect, that could be useful to correct small-angle strabismus, and may be suggested as a vessel-sparing technique when two rectus muscles have previously been operated in the same eye.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05778565.

Anterior segment ischemia following strabismus surgery in a young adult using gender-affirming estrogen hormone therapy

Well-known risk factors for anterior segment ischemia (ASI) following strabismus surgery include ipsilateral surgery on three or more rectus muscles, older age, and vasculopathy. ASI is rarely reported in young patients following uneventful strabismus surgery on two ipsilateral rectus muscles. We report a 30-year-old transgender female on long-term estrogen therapy who underwent strabismus surgery involving recessions of both lateral rectus muscles, the right inferior rectus muscle, and the left superior rectus muscle. The left eye developed severe ASI with hypotony maculopathy that was resistant to topical medications, oral steroids, anterior chamber reformation, and intravitreal steroid injection. Following phacoemulsification with intraocular lens and capsular tension ring insertion 1 year later, intraocular pressure and hypotony maculopathy improved.

Anterior segment ischemia following modified Nishida procedure

Anterior segment ischemia (ASI) can occur following strabismus surgery on multiple muscles. Procedures such as modified Nishida procedure (MNP) have been developed to reduce the risk of ASI. We report the case of a 68-year-old patient presenting with traumatic bilateral abducens nerve palsies who required surgical intervention. We performed MNP with medial rectus recession. The patient presented with reduced vision, corneal edema, anterior chamber reaction, and pupillary dilation 24 hours after surgery. A diagnosis of ASI was made, and immediate reversal of the Nishida procedure was performed. Symptoms improved within 24 hours. In this case, ASI may have been caused by ligation and compression of ciliary arteries due to overstretching of the vertical rectus muscles during transposition.

Increased angiogenic factors in the aqueous and vitreous humors after disinsertion of extraocular muscle and the effects of triamcinolone acetate injection

The four extraocular rectus muscles in the rabbits were disinserted for induction of anterior segment ischemia (ASI) and the changes in the concentrations of prostaglandin E2 (PGE2), hypoxia-inducible factor-1 (HIF-1α), and vascular endothelial growth factor (VEGF) in the aqueous and vitreous humor were evaluated. Disinsertion of four rectus muscles in rabbits was performed in the right eyes of rabbits (ASI group). The concentrations of PGE2, HIF-1α, and VEGF in the aqueous and vitreous humor were measured at 1, 3, 6, 12, and 24 h by ELISA. The concentrations were compared with those of the fellow eyes (contralateral group) and normal healthy eyes (control group). Subconjunctival injection of triamcinolone acetonide (TA) was administered and three cytokine concentrations in the aqueous humor and vitreous humor were measured at 12 h after TA injection. A total of 48 eyes from 28 rabbits were included. The concentrations of PGE2, HIF-1α, and VEGF in the aqueous humor in the ASI and contralateral groups were significantly higher than those in the control group (p < 0.05, all). The aqueous and vitreous humor concentrations of VEGF in eyes with simultaneous TA injection were significantly lower than were those in the ASI group (p = 0.02, all). The concentration of PGE2, HIF-1α, and VEGF in the aqueous humor was increased after induction of ASI and TA injection seems to be effective in inhibiting VEGF elevation in ASI.

Double-under muscle transposition: an effective surgical option for large-angle paralytic strabismus

PURPOSE

To describe our surgical outcomes using a novel muscle transposition procedure, or double-under muscle transposition (DUT), in the treatment of paralytic strabismus.

METHODS

In this surgery, the split halves of the superior and inferior rectus muscles opposite the paralyzed muscle are disinserted, crossed under both the remaining half and the paralyzed muscle, and anchored at opposite corners of the insertion of the paralyzed muscle. The medical records of consecutive patients who underwent DUT were retrospectively reviewed. Outcome measures were angle of deviation and duction deficit.

RESULTS

Seven patients were included. Diagnoses included WEBINO (n = 1), rupture of the medial rectus muscle (n = 1), and abducens nerve palsy (n = 5). DUT alone was performed in 3 patients; DUT combined with antagonist muscle recession, in 4 patients. One patient underwent the surgery bilaterally. Mean follow-up was 17 ± 18+ months (range, 7-57). Preoperative angles of distance deviation ranged from 25^Δ to 142^Δ in magnitude. All except a single patient had duction limitation of grade -5. The mean change in distance deviation for DUT alone for each operated eye was 60^Δ ± 6^Δ (53^Δ-65^Δ); for combined surgery, 69^Δ ± 23^Δ (range, 52^Δ-103^Δ). Final mean angle of deviation at distance was +2^Δ ± 3^Δ (-4^Δ to 0^Δ), although an additional surgery was required for large overcorrections in 2 patients. Duction limitation improved in all patients. One patient experienced a postoperative vertical deviation.

CONCLUSIONS

DUT may be an alternative for patients with severely paralytic strabismus not likely to resolve with previously reported muscle transposition surgeries. Overcorrection may occur in some cases.

Anterior Segment Ischemia After Peripheral Annular Lamellar Sclerokeratoplasty for Advanced Terrien Marginal Degeneration

ABSTRACT

A man with 360° bilateral peripheral thinning, peripheral vascularization, and lipid deposition diagnosed with Terrien marginal degeneration, underwent a 360° peripheral annular lamellar sclerokeratoplasty (PALK) (tuck-in) in the right eye for 90% peripheral thinning and high astigmatism. One-week postoperatively, a sudden drop in vision to counting fingers 1 m from 20/50 with circumciliary congestion, diffuse corneal edema, intense anterior chamber inflammation, keratic precipitates with fixed dilated pupil, and hypotony led to a diagnosis of suspected anterior segment ischemia. Anterior segment fluorescein angiography was suggestive of ischemia. After intensive topical and systemic steroids tapered over 6 months, his symptoms and signs improved. At the last follow-up 4 years later, his best contact lens-corrected visual acuity was 20/30. Anterior segment ischemia has not been reported after a PALK for advanced corneal ectatic disorders. Prompt diagnosis and commencement of intensive steroids was helpful in reversing this condition.

Neovascularization of angle following trabeculectomy augmented with mitomycin-C

The purpose of this study was to report a case of neovascularization of angle (NVA) following trabeculectomy with mitomycin-c (MMC) in a patient with primary open-angle glaucoma. This case report describes a 68-year-old woman who developed NVA and hyphema 2 weeks following an uneventful trabeculectomy with MMC. Trabeculectomy may be associated with serious and vision-threatening complications such as hypotony, suprachoroidal hemorrhage, endophthalmitis, and bleb-related complications. However, neovascularization of the anterior segment is not a commonly reported complication. Neovascularization of the anterior segment is a rare postoperative complication that usually occurs following strabismus or retinal detachment surgeries. The underlying ischemic trigger for anterior segment neovascularization is usually a posterior segment pathology or carotid artery insufficiency. These causative factors were excluded in our patient by lack of any abnormal finding in fundus fluorescein angiography and carotid Doppler ultrasonography. The patient received three subconjunctival bevacizumab injections (1.25 mg/0.1 ml) with frequent topical steroids and showed marked regression of the neovessels. The bleb was functional, and intraocular pressure remained at low teen afterward. NVA following trabeculectomy without any posterior segment or carotid pathologies responded well to subconjunctival bevacizumab and topical steroids.

[Strabismus surgery and anterior segment ischemia syndrome]

The review summarizes the results of studies related to ischemia of the anterior segment of the eye after surgeries on straight extraocular muscles for strabismus and presents classification, clinical manifestations and risk factors for the development of the syndrome. The principal prevention measures for the clinically significant syndrome are focused on limiting the extent of surgical intervention: in the presence of risk factors and the need for intervention on more than two muscles - staged surgical treatment (i.e. ensuring a time interval between surgeries) that allows collateral circulation to form properly.

A Review of Corneal Endotheliitis and Endotheliopathy: Differential Diagnosis, Evaluation, and Treatment

The corneal endothelium plays an integral role in regulating corneal hydration and clarity. Endotheliitis, defined as inflammation of the corneal endothelium, may disrupt endothelial function and cause subsequent visual changes. Corneal endotheliitis is characterized by corneal edema, the presence of keratic precipitates, anterior chamber inflammation, and occasionally limbal injection, neovascularization, and co-existing or superimposed uveitis. The disorder is classified into four subgroups: linear, sectoral, disciform, and diffuse. Its etiology is extensive and, although commonly viral, may be medication-related, procedural, fungal, zoological, environmental, or systemic. Not all cases of endothelial dysfunction leading to corneal edema are inflammatory in nature. Therefore, it is imperative that practitioners consider a broad differential for patients presenting with possible endotheliitis, as well as familiarize themselves with appropriate diagnostic and therapeutic modalities.

Ocular hypotony: A comprehensive review

Ocular hypotony is an infrequent, yet potentially vision-threatening, entity. The list of differential causes is extensive, involving any condition that may compromise aqueous humor dynamics or the integrity of the globe and sometimes following medical treatments or procedures. Depending on the cause and the clinical impact, treatment options aim to correct the underlying pathology and to reestablish anatomical integrity, as well as visual function. We review the pathophysiology, clinical presentation, different causes, and associated therapeutic options of ocular hypotony.

The management of large-angle esotropia in Graves ophthalmopathy with combined medial rectus recession and lateral rectus resection

PURPOSE

To describe surgical management and outcomes for large-angle esotropia of ≥50^Δ secondary to Graves ophthalmopathy using combined initial nonadjustable medial rectus recessions and lateral rectus resections.

METHODS

The medical records of consecutive patients undergoing strabismus surgery for large-angle esotropia secondary to Graves ophthalmopathy from 1995 to 2012 by a single surgeon at each of two institutions was performed. Patient characteristics, surgical technique, and pre- and postoperative measurements of ocular alignment were analyzed. A modified Gorman diplopia scale was used to assess outcome.

RESULTS

Of 38 patients, 36 had bilateral nonadjustable medial rectus recessions and lateral rectus resections as initial treatment for esotropia, and 6 patients underwent simultaneous vertical muscle surgery. Mean preoperative horizontal deviation was 60^Δ and mean preoperative vertical deviation was 10^Δ. Of the 38 patients, 19 (50%) reached the primary outcome, including 5 of 6 (85%) who had no preoperative vertical strabismus. The indications for reoperation were vertical strabismus in 13 of 21 patients (62%), residual esotropia in 7 of 21 (33%), and consecutive exotropia in 1 of 21 (5%). With a median follow-up of 13.2 months after first surgery, 32 of 38 patients (84%) reached the secondary outcome.

CONCLUSIONS

Combining nonadjustable medial rectus recessions with lateral rectus resections can be a beneficial primary treatment for large-angle esotropia in patients with Graves ophthalmopathy, especially in those patients with small or no associated vertical strabismus.

Risk of Anterior Segment Ischemia Following Simultaneous Three Rectus Muscle Surgery: Results from a Single Tertiary Care Centre

PURPOSE

The aim of the study was to determine the risk of anterior segment ischemia (ASI) after simultaneous three rectus muscle surgery.

METHODS

A retrospective cohort study was conducted. All patients who underwent simultaneous three rectus muscle surgery from January 2003 to December 2014 were included. Medical records were reviewed for signs of acute ASI in the postoperative period or presence of any late sequelae. Those patients who had pre-existing corneal pathology obscuring visualisation of anterior chamber and iris were excluded.

RESULTS

A total of 87 patients (54 males and 33 females) were included in the analysis. The mean age at the time of surgery was 22.5 ± 12.9 years (range 3.5 to 69.5 years). The common indications for surgery were monocular elevation deficit, sensory strabismus and third and sixth cranial nerve palsies. Mild form of ASI was seen in two patients, with no systemic or local illness, aged 30 and 9 years respectively. Both the patients underwent surgery on two vertical rectus muscle and one horizontal rectus muscle via the fornix approach. ASI resolved with topical steroids within two weeks in both the patients.

CONCLUSIONS

The risk of anterior segment ischemia after uncomplicated simultaneous three rectus muscle surgery was found to be 2.3% (95% CI = 0.3 to 8.1). It may occur in otherwise healthy young patients and even after fornix approach surgery.

Surgical outcomes following rectus muscle plication versus resection combined with antagonist muscle recession for basic horizontal strabismus

PURPOSE

To evaluate change in ocular alignment and surgical success of rectus muscle plication versus resection when coupled with antagonist muscle recession for basic esodeviations and exodeviations.

METHODS

The medical records of consecutive patients with basic horizontal strabismus who underwent a rectus muscle plication or resection combined with a known amount of antagonist muscle recession from January 2009-June 2016 by one surgeon were reviewed retrospectively. Changes in ocular alignment and surgical success at 4-16 weeks after surgery and reoperation rates for plication compared to resection were assessed. Success was defined as undercorrection of ≤10^Δ and overcorrection of ≤4^Δ at distance.

RESULTS

A total of 162 patients with basic esotropia (88 lateral rectus muscle plications; 74 lateral rectus resections) and 60 patients with basic exotropia (31 medial rectus muscle plications; 29 medial rectus resections) were included. Success rates at 4-16 weeks after surgery were 95.5% for lateral rectus plication, 89.2% for lateral rectus resection, 77.4% for medial rectus plication, and 96.6% for medial rectus resection. No significant differences were found when analyzing the change in ocular alignment between the plication and resection groups for patients with either basic esotropia or basic exotropia. Reoperation rates were low for all groups (range, 3.2%-5.4%) during a follow-up period of 4 weeks to 72 months.

CONCLUSIONS

Horizontal rectus muscle plication produced similar changes in ocular alignment and surgical success compared to rectus muscle resection at 4-16 weeks after surgery when coupled with comparable amounts of antagonist muscle recession.

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.

Outcomes After Superior Rectus Transposition and Medial Rectus Recession Versus Vertical Recti Transposition for Sixth Nerve Palsy

PURPOSE

To compare the effectiveness of superior rectus transposition and medial rectus recession (SRT/MRc) vs inferior and superior rectus transposition (VRT) for acquired sixth nerve palsy.

DESIGN

Consecutive, interventional case series.

METHODS

The medical records of a consecutive series of patients with acquired sixth nerve palsy who underwent VRT or SRT/MRc by a single surgeon were reviewed. The preoperative and postoperative findings were compared between the 2 groups.

RESULTS

Eight patients (mean age, 46.8 years) underwent SRT/MRc and 8 patients underwent VRT (mean age, 51.1 years). Lateral fixation was performed on all but 4 patients in the VRT group. Preoperative esotropia in primary position and abduction deficit were similar in both groups (SRT/MRc, 41.9 prism diopter [PD], -4.6; VRT, 55.6 PD, -4.5; P = .195, 1.0). The SRT/MRc group underwent a mean MR recession of 6 (range, 5-7) mm. Four patients in the VRT later underwent MR recession (mean 5.3 mm, range 5-6 mm). In addition, 5 patients in the VRT group had 1 or more botulinum toxin injections in the medial rectus muscle. No additional procedures were performed in the SRT/MR group. Fewer additional procedures were performed with SRT/MR (SRT/MR, 0; VRT, 1.8 ± 1.2; P < .010). At last follow-up, residual esotropia (SRT/MRc, 7.1 PD; VRT, 10.3 PD; P = .442) was similar in both groups, but abduction was better in the SRT/MRc group (SRT/MR, -3.0 ± 0.7; VRT, -3.8 ± 0.4; P = .038). There were no new persistent vertical deviations or torsional diplopia.

CONCLUSIONS

Final outcomes were similar with SRT/MRc vs VRT. However, fewer additional surgical procedures were needed with SRT/MR.

Anterior Segment Ischemia after Strabismus Surgery

A 46-year-old male patient was referred to our clinic with complaints of diplopia and esotropia in his right eye that developed after a car accident. The patient had right esotropia in primary position and abduction of the right eye was totally limited. Primary deviation was over 40 prism diopters at near and distance. The patient was diagnosed with sixth nerve palsy and 18 months after trauma, he underwent right medial rectus muscle recession. Ten months after the first operation, full-thickness tendon transposition of the superior and inferior rectus muscles (with Foster suture) was performed. On the first postoperative day, slit-lamp examination revealed corneal edema, 3+ cells in the anterior chamber and an irregular pupil. According to these findings, the diagnosis was anterior segment ischemia. Treatment with 0.1/5 mL topical dexamethasone drops (16 times/day), cyclopentolate hydrochloride drops (3 times/day) and 20 mg oral fluocortolone (3 times/day) was initiated. After 1 week of treatment, corneal edema regressed and the anterior chamber was clean. Topical and systemic steroid treatment was gradually discontinued. At postoperative 1 month, the patient was orthophoric and there were no pathologic symptoms besides the irregular pupil. Anterior segment ischemia is one of the most serious complications of strabismus surgery. Despite the fact that in most cases the only remaining sequel is an irregular pupil, serious circulation deficits could lead to phthisis bulbi. Clinical properties of anterior segment ischemia should be well recognized and in especially risky cases, preventative measures should be taken.

CONCURRENT ENDOPHTHALMITIS AND ANTERIOR SEGMENT ISCHEMIA AFTER STRABISMUS SURGERY

BACKGROUND/PURPOSE

To report a case of simultaneous endophthalmitis and anterior segment ischemia (ASI) that occurred in a patient after strabismus surgery. This is the first known case of both complications occurring at the same time.

METHODS

Case report.

RESULTS

A 60-year-old woman presented with eye pain and loss of vision 6 days after uncomplicated strabismus surgery for thyroid eye disease. On examination, she had corneal edema, anterior segment fibrin, an atonic iris, and no view to the posterior segment. On fluorescein angiography of the anterior segment, a large portion of the iris was nonperfused. Posterior segment ultrasound showed dense vitritis and a choroidal abscess. Intraoperative cultures grew methicillin-resistant Staphylococcus aureus.

CONCLUSIONS

Endophthalmitis and anterior segment ischemia are both exceedingly rare complications of strabismus surgery. It is possible that each one occurred independently, but more likely one process potentiated the other. One possible mechanism is inflammation-induced thrombosis.

Vertical rectus transpositions in sixth nerve palsies

PURPOSE OF REVIEW

There are many surgical options to address a sixth nerve palsy including transpositions of the vertical recti to the lateral rectus. This review will summarize the results from variations on transpositions as they apply to sixth nerve palsies.

RECENT FINDINGS

Transposition of both vertical recti with posterior fixation creates the greatest correction of esotropia in primary position with largest field of single vision. Transposition of the superior rectus alone preserving anterior segment circulation achieves effects similar to transposition without posterior fixation. Augmentation with partial transposition also creates similar improvement in esotropia with possibilities for adjustable sutures and circulation preservation.

SUMMARY

These various options on transpositions allow options to specifically address surgeon preferences and patient needs to select the appropriate surgery.

Iatrogenic Injury to Medial Rectus After Endoscopic Sinus Surgery

Endoscopic sinus surgery (ESS) is the mainstay of the treatment in sinus disorders, to re-establish the drainage of the affected sinus. The close proximity of the orbital structures to paranasal sinuses makes them vulnerable to inadvertent injury during the sinus surgery. Medial rectus (MR) muscle is the most commonly injured extraocular muscle during ESS due to its anatomic proximity to the thin medial wall of the orbit. This is a non-comparative, retrospective, interventional case series of six patients presenting with MR injury after ESS. We discuss the management, outcome and review the published literature. A total of six patients met the inclusion criteria. The presenting complaints were diplopia, squinting and limitation of ocular movements. Two patients underwent surgical exploration of the MR muscle and reattachment of the muscle along with injection botulinum to the antagonist lateral rectus muscle. Two patients who had small angle strabismus and who were able to fuse were advised orthoptic exercises and prisms as management. Remaining two patients were advised surgical intervention to correct strabismus but they declined further surgical intervention. Management of MR injury following ESS is complex, often resulting in suboptimal outcomes. Since early intervention is associated with better outcomes, early referral by otolaryngologists to ophthalmologists would result in better outcome.

Complications of strabismus surgery: incidence and risk factors

PURPOSE

To perform a systematic review of the complications of strabismus surgery, focusing on incidence and risk factors.

MATERIAL AND METHODS

A systematic literature search was performed using the Medline and Cochrane databases.

RESULTS

Local complications, such as conjunctival injection and mild scarring, are almost universal but only rarely have long-term clinical significance. There are several important complications that are uncommon but associated with significant long-term sequelae, including slipped muscles, lost muscles, stretched scars, incarcerated muscles, pulled-in-two syndrome, periocular infections, orbital cellulitis, scleral perforations, retinal detachments, endophthalmitis, anterior segment ischemia, and surgical errors.

DISCUSSION

Strabismus surgery is associated with a number of common and serious complications, and it is important for both surgeons and patients to be aware of the risks.

The effect of rectus muscle recession, resection and plication on anterior segment circulation in humans

BACKGROUND

Plication is an alternative tightening procedure to resection. In monkeys, plication has been shown to preserve anterior segment circulation compared with full-tendon tenotomy, but this is unconfirmed in humans.

PURPOSE

To evaluate anterior segment circulation by iris angiography before and after strabismus surgery in humans.

METHODS

Prospective, blinded study of 14 patients (mean age (SD), 58.6 (14.3)) undergoing plication and/or full tendon tenotomy (resection or recession) from August 2013 to March 2014. Eight patients (mean age (SD), 59.0 (13.3)) underwent plication of one muscle with or without recession of a second muscle on the same eye and six patients (mean age (SD), 58.2 (16.8)) underwent tenotomy of one to two muscles on the same eye. Preoperative and postoperative iris angiograms were compared for changes in perfusion by a masked examiner. In patients undergoing binocular surgery, one eye was chosen preoperatively to be the study eye.

RESULTS

Postoperative iris filling defects were present in four patients (67%) after tenotomy and one patient (12.5%) after plication (p=0.09). Of the seven total vertical rectus muscles operated (three tenotomies and four plications), filling defects were present after three tenotomies and one plication (100% vs 25%; p=0.14). Of the 13 total horizontal rectus muscles operated (eight tenotomies and five plications), filling defects were present after one tenotomy and none of the plications (13% vs 0%; p=0.99).

CONCLUSIONS

Rectus muscle plication spares the ciliary vessels and may be considered a safer alternative to resection for patients at risk for anterior segment ischaemia, especially when surgery involves a vertical rectus muscle.

Anterior Segment Ischemia in Viper Bite

PURPOSE

To describe the clinical and histopathological features of post viper bite anterior segment ischemia.

METHODS

Seven patients with ocular complications following viper bite referred to uveitis clinic had slit-lamp examination, intraocular pressure (IOP) measurement, and fundus evaluation. Iris and fundus fluorescein angiography was performed on 2 patients. Histopathological examination was performed on iris tissues collected during cataract surgery.

RESULTS

Strikingly similar clinical findings were noted, including circumpupillary superficial iris atrophy, mid dilated fixed pupil, marked pigment dispersion, low IOP, and cataract. All clinical signs were noted only in the anterior segment; the posterior segment was normal. Histopathology of iris revealed atrophy of iris stroma, necrotic iris pigment epithelium, and infiltration of T lymphocytes and fibrous membrane. Poor visual outcome was noted in patients with low IOP.

CONCLUSION

Viper bite victims presented with clinical and histopathological signs of anterior segment ischemia and secondary inflammatory signs mimicking uveitis.

Natural course of anterior segment ischemia after disinsertion of extraocular rectus muscles in an animal model

PURPOSE

To compare the frequency and severity of anterior segment ischemia (ASI) after disinsertion of extraocular rectus muscles in a rabbit eye model.

METHODS

The rectus muscles of eyes of 84 rabbits were removed. In 42 rabbits one eye underwent three-muscle surgery, whereas the fellow eye underwent two-muscle surgery. In the other 42 rabbits, one eye underwent three-muscle surgery and the fellow eye four-muscle surgery. The surgery included disinsertion together with extirpation of the anterior 10 mm of the muscle. Each eye was examined daily to detect the presence of ASI. Anti-inflammatory eyedrops were not used in any subject. The severity of inflammation and time to complete resolution of inflammatory signs were documented. After inflammation resolved, both eyes of each rabbit were enucleated and studied by a pathologist.

RESULTS

The incidence of ASI was 9.5% in the two-muscle group, 31% in the three-muscle group, and 50% in the four-muscle group (P =0.001). ASI eyes all developed signs on the first postoperative day. Inflammation resolved in 4-38 days. The incidence of ASI increased significantly with the number of muscles operated on. Permanent complications were rare and histopathology results were normal in most cases.

CONCLUSIONS

Inflammation resolved spontaneously in all involved eyes without intervention and only minor clinical or pathologic changes were noted. One eye, however, developed severe sequela but was still preserved. The severity of ASI was directly correlated to the number of operated rectus muscles. Our findings suggest a self-limited nature of ASI in this rabbit model.

Kestenbaum procedure with combined muscle resection and tucking for nystagmus-related head turn

BACKGROUND

Literature has dealt extensively with dose-effect relations for recess-resect procedures for correction of horizontal nystagmus-related head turn. However, muscle tucking procedures have some advantages compared to resection procedures. Aim of this study was to evaluate dose-effect relations of Kestenbaum surgery with symmetrical combined recession and tucking (instead of resection) of the horizontal rectus muscles for the reduction of a nystagmus-related head turn.

METHODS

In a retrospective study, clinical findings of 42 patients who consecutively underwent treatment in our institution between 2000 and 2011 were investigated. The patients were aged 4-57 years (median age 6 years). For all patients, surgery aimed to correct a horizontal head turn (to the right: 18 patients) due to infantile nystagmus. The head turn was measured with a goniometer with the patient fixing the smallest age-appropriate target distinguishable for the patient.

RESULTS

The median absolute head turn before surgery was 30° (min. 15°, max. 45°). The four horizontal rectus muscles were recessed or tucked between 5.5 and 10 mm, median 9 mm. All four muscles were recessed or tucked for the same amount. At the first postoperative day, the median dose-effect relation was 1.88° reduction of head turn per millimeter surgery on one eye (min. 0.5°/mm, max. 3.2°/mm). The median head turn was 0° (min. -20°, max. 15°). Surgery was considered successful in 88% of the patients with a reduction of the head turn to max. 10°. Data of 36 patients were available for the long-term postoperative period (median 1.5 years; min. 6 weeks, max. 11 years). The median head turn was 10° (min. -16°, max. 30°). The median dose-effect relation was reduced to 1.35°/mm per eye (min. 0°/mm, max. 2.9°/mm). Surgery was considered successful in 72 % of the patients with a reduction of the head turn to max. 10°. Three patients showed an overcorrection with a head turn of 8°, 15° and 16° to the other side. A squint has not been induced.

CONCLUSIONS

The dose-effect relation for Kestenbaum surgery with symmetrical combined recession and tucking of the horizontal rectus muscles is comparable to the dose-effect relation reported by other authors for symmetrical combined recession and resection.

Scleral buckle removal: indications and outcomes

Primary scleral buckling has been an effective means to reattach the retina for over 50 years. After surgery, complications may arise that require scleral buckle (SB) removal. The most common indications for SB removal are extrusion, infection, and pain. I review the pertinent literature in an effort to develop guidelines for when to remove a SB.

Management of disinserted inferior rectus muscle by fixation of globe to the inferior orbital margin

Trauma to the orbital floor is often associated with trauma to the inferior rectus muscle. The currently available options yield inconsistent postoperative results. The authors describe a new technique in which the globe was fixed to the inferior orbital margin with the help of a silicone band and titanium orbital plate.

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.

Squint surgery in TED -- hints and fints, or why Graves' patients are difficult patients

Endocrine ophthalmopathy is the most common cause of acute onset diplopia in middle aged or older individuals. Ocular muscle involvement is characterized by myositis followed by fibrosis: this causes a stiffness and a shortening of the muscles involved with restriction of ocular movements: so the impairment of rotation is due to a mechanical obstacle and not to a paresis. Prisms are rarely useful in relieving diplopia and the majority of symptomatic patients need squint surgery. Timing of surgery is very important and two considerations are to be kept in mind: first, the systemic disease must be in remission and the ocular deviation must be stable for at least six months; second, if more than one surgical procedure is needed for the ophthalmopathy, muscle surgery has its right place after orbital surgery and before lid surgery. Obviously dealing with restrictive disorders, surgery is based on weakening procedures of the affected muscles: identifying the affected muscles is of crucial importance and may be sometime difficult for the presence of misleading signs; great advances have been made in surgical technique with the development of adjustable sutures and of topical anesthesia. Prognosis is usually good with more than 80% of patients recovering a useful field of binocular single vision with one procedure and more than 90% with two or more procedures.

Anterior segment ischemia after two-muscle surgery in a patient with radiation-treated nasopharyngeal carcinoma

Anterior segment ischemia after strabismus surgery is a rare occurrence. Risk factors include single-stage surgery of three or more muscles in one eye, dysthyroid eye disease, and advanced age. The authors report a case of anterior segment ischemia after single-stage surgery of two horizontal muscles without previous reported risk factors. However, the patient had received radiotherapy for nasopharyngeal carcinoma more than 20 years ago. The case was successfully treated with systemic steroids but with reduced best-corrected visual acuity. Previous radiotherapy in the related orbital field may be a new risk factor for this condition.

Bilateral necrotizing scleritis following strabismus surgery for thyroid ophthalmopathy

A case of a bilateral necrotizing scleritis following strabismus surgery for thyroid ophthalmopathy is described. A 71-year-old man was operated on for esotropia due to prior and equilibrated Grave's disease. Two weeks after surgery, he had a scleral necrosis that was located on the surgery sites (insertion of the two medial rectus muscles). There was no infectious or autoimmune etiology. The pathogenic mechanism was ischemic and inflammatory, doubtless facilitated by the thyroid ophthalmopathy. The outcome was favorable after 3 weeks of antibiotic and anti-inflammatory treatment. To the authors' knowledge, this is the first bilateral case of this complication.

Surgical management of severe cocontraction, globe retraction, and pseudo-ptosis in Duane syndrome

BACKGROUND

Correction of severe cocontraction and pseudo-ptosis present unique surgical challenges in patients with Duane syndrome.

METHODS

We report four Duane syndrome patients with esotropia in primary position, poor abduction, and severe cocontraction causing limitation to adduction, globe retraction, and pseudo-ptosis. All were treated with partial tendon transposition of the vertical rectus muscles augmented with Foster fixation sutures and surgical weakening of the ipsilateral lateral rectus muscle. One patient had a large recession of the lateral rectus muscle, and in three patients, the lateral rectus muscle was inactivated by removing from the globe and attaching its insertion to the lateral orbital wall.

RESULTS

Postoperatively, all patients were aligned within eight prisms diopters of orthotropia, had no face turn, and improved adduction and abduction. The two patients who had restriction to abduction on intraoperative forced ductions also had residual esotropia in primary position and underwent recession of the ipsilateral medial rectus muscle as a second procedure. Postoperative binocular single visual field was enlarged by 56 to 500% in the three patients who were tested preoperatively and postoperatively. Globe retraction and cocontraction were markedly relieved. Palpebral fissure widened 1.0 and 6.0 mm in two patients who had preoperative and postoperative measurements.

CONCLUSION

In Duane syndrome patients, severe cocontraction, globe retraction, and limitation to adduction may improve if the lateral rectus muscle is maximally recessed or its insertion is inactivated from the globe. Partial transposition of the vertical rectus muscles augmented with Foster sutures improved the angle of esotropia in primary position and abduction. Medial rectus muscle recession is indicated when the passive forced duction test reveals moderate-to-severe restriction to abduction.

Partial rectus muscle-augmented transpositions in abduction deficiency

PURPOSE

Lateral posterior fixation sutures increase the effect of full rectus extraocular muscle transpositions. Partial rectus muscle transposition may be indicated to minimize the risk of anterior ischemia when multiple rectus muscles require surgery to achieve ocular alignment.

PURPOSE

To report a modification of full vertical rectus muscle transposition with lateral posterior fixation sutures for use in patients at risk for anterior segment ischemia.

METHODS

Ten cases of unilateral split rectus muscle transposition augmented with lateral posterior fixation sutures were analyzed. Five patients had Duane's syndrome with esotropia in primary position, and five patients had sixth-nerve palsy.

RESULTS

Seven patients had a history of ipsilateral rectus muscle surgery, and three patients underwent simultaneous surgery on ipsilateral horizontal rectus muscles. In Duane's syndrome patients, the preoperative angle of deviation at distance was 15.8 +/- 5.8 prism diopters (PD) (range, 10 to 25) compared with 3.2 +/- 4.4 PD (range, 0 to 8) postoperatively (P =.005). In patients with sixth-nerve palsy, the preoperative angle of deviation at distance was 45.2 +/- 23.9 PD (range, 16 to 80) compared with -5 +/- 14.1 PD (range, -30 to 5) postoperatively (P =.004). Postoperative binocular single visual fields enlarged in seven of seven patients.

CONCLUSION

Partial rectus muscle-augmented transposition allows surgery on multiple ipsilateral rectus muscles in (1) Duane's syndrome patients with esotropia, marked cocontraction, and/or limitation to both horizontal rotations and in (2) sixth-nerve palsy patients with ipsilateral medial rectus tightness. Augmented partial rectus muscle transpositions improve ocular alignment and may enlarge binocular single fields in patients with persistent deviations despite previous muscle surgery.

Ophthalmic complications of endoscopic sinus surgery

The intimate anatomical relationship between the orbit and the paranasal sinuses places the orbit and its contents at risk of harm from primary pathologic processes of the sinuses. In the absence of ophthalmic signs or symptoms, ophthalmologists are not routinely involved in the management of patients with sinus disease. Occasionally, some patients may develop ophthalmic complaints after surgical intervention. The orbit, optic nerve, extraocular muscles, and lacrimal drainage system are susceptible to injury during endoscopic sinus surgery. The risk of injury is related to the skill of the sinus surgeon, history of previous surgery, extent and severity of disease, and anatomic variation. Furthermore, recent advances in endoscopic sinus surgery, in particular the use of powered cutting instruments, has resulted in a novel mechanism of injury to the ocular structures.

Medial rectus muscle injuries associated with functional endoscopic sinus surgery: characterization and management

OBJECTIVE

To characterize and evaluate treatment options for medial rectus muscle (MR) injury associated with functional endoscopic sinus surgery (FESS).

DESIGN

Retrospective interventional case series.

PARTICIPANTS

A total of 30 cases were gathered from 10 centers.

METHODS

Cases of orbital MR injury associated with FESS surgery were solicited from members of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) through an e-mail discussion group.

MAIN OUTCOME MEASURES

Variables assessed included patient demographics, computerized tomography and operative findings, extent of MR injury and entrapment, secondary orbital/ocular injuries, initial and final ocular alignment and ductions, and interventions.

RESULTS

A spectrum of MR injury ranging from simple contusion to complete MR transection, with and without entrapment, was observed. Four general patterns of presentation and corresponding injury were categorized.

CONCLUSIONS

Medial rectus muscle injury as a complication of FESS can vary markedly. Proper characterization and treatment are important, particularly with reference to the degree of direct MR injury (muscle tissue loss) and entrapment. Patients with severe MR disruption can benefit from intervention but continue to show persistent limitation of ocular motility and functional impairment. Prevention and early recognition and treatment of these injuries are emphasized.

A retrospective pilot study to assess the impact of strabismus surgery on the corneal endothelium in children

PURPOSE

To investigate if strabismus surgery has an impact on the corneal endothelium in children.

METHODS

Fourteen children who had undergone uncomplicated strabismus surgery an average of 41 months previously (range 24-73 months) were compared with a group of age-matched (range 5-12 years) and refractive error (RE)-matched (range -4.74 to +4.25 D) children. Following noncontact specular microscopy, areas of at least 100 cells were measured, the number of sides for each cell recorded, and endothelial cell density (ECD) calculated from the area measures. Corneal diameter was measured with a clinical rule, corneal curvature with a manual keratometer, central corneal thickness (CCT) by ultrasound pachometry, and IOP by non-contact tonometry.

RESULTS

The average ECD (+/-S.D.) in the post-surgery group was 4467+/-627 cells mm(-2), which was significantly higher (p < 0.02) than in the control group (3781+/-452 cells mm(-2)). This was because the average endothelial cell area in the surgery group was significantly smaller than in the control group (p < 0.005; 252+/-25 microm2 vs 296+/-29 microm2). Differences in cell areas were slightly greater for smaller cells (-15.7% for five-sided cells, -15.6% for six-sided cells, -14.3% for seven-sided cells and -13.8% for eight-sided cells). The cell differences appear to be related to both a slightly smaller corneal diameter (11.00+/-0.52 mm vs. 11.21+/-0.58 mm) and a slightly higher CCT (0.528+/-0.033 mm vs. 0.515+/-0.032 mm) in the post-operative group.

CONCLUSION

The endothelial mosaic in children after strabismus surgery can show a higher than expected ECD value and slight cell pleomorphism. These signs indicate that there might be differences in eye growth and endothelial inflammatory stress associated with uneventful strabismus surgery.

Indocyanine green angiography of the anterior segment in patients undergoing strabismus surgery

BACKGROUND

Anterior segment imaging using fluorescein angiography is only suitable in lightly pigmented irides as the brown pigmentation of the iris masks fluorescein transmission. Indocyanine green (ICG) angiography has excellent penetration of pigment epithelium and, therefore, has potential application in detecting perfusion changes of dark irides after strabismus surgery.

METHODS

A prospective study was conducted on patients older than 15 years undergoing strabismus surgery. A fundus camera was focused on the arteriolar tufts of the pupillary margin and 50 mg of ICG (concentration of 12.5 mg/ml) was given intravenously. Images were then obtained at 1 minute intervals of 5 minutes' duration.

RESULTS

45 patients with a mean age of 54.6 years and a mean follow up period of 8.6 weeks were studied. There were 23 patients in the primary surgery group, 11 in the secondary surgery group, and 11 in the staged group. Iris ICG angiograms were successfully performed in all patients. No persistent filling defect was detected in the primary and secondary horizontal recti surgery groups or in the secondary or staged vertical and combined vertical rectus groups 6-8 weeks postoperatively. 57% of both primary vertical and combined vertical and horizontal groups showed defects in the early postoperative phase. Only three cases demonstrated late perfusion defects in this series.

CONCLUSION

ICG can detect iris perfusion changes in dark irides after strabismus surgery. Iris reperfusion was achieved in the majority of the cases.

Augmented Hummelsheim procedure for paralytic strabismus

PURPOSE

To report a modification of the Hummelsheim procedure for use in the management of paralytic strabismus.

METHODS

Eight patients with paralytic strabismus secondary to third nerve palsy (n=1), sixth nerve palsy (n=3), combined cranial nerve palsy (n=1), or extraocular muscle damage (n=3) were treated using a modification of the Hummelsheim transposition procedure. The procedure involves half-tendon transpositions of the adjacent rectus muscles to the insertion of the paralyzed muscle, coupled with resection of the transposed halves. Further augmentation was achieved by surgical or pharmacologic weakening of the ipsilateral (n=6) or contralateral (n=1) antagonist. One patient underwent the procedure bilaterally. All patients underwent at least 6 weeks of follow-up.

RESULTS

The mean preoperative primary position deviation in the seven unilateral cases was 54 prism diopters (delta) (range: 25-85 delta). Preoperative forced ductions were positive in four cases. Resections varied from 4-8 mm. Ipsilateral antagonist recession varied from 0-14 mm. The mean change was 52 delta (range: 25-85 delta). Five cases were aligned within 15 delta of orthotropia at 6 weeks. No cases of anterior segment ischemia or induced vertical deviation were noted.

CONCLUSION

The modified Hummelsheim procedure appears capable of correcting large angles of strabismus associated with muscle palsy of various etiologies. It is safe, amenable to adjustable sutures, and relatively tissue- and vessel-sparing. Additional study is required to understand more fully the procedure's component effects and its interaction with ocular rotation.

Skeletal muscle response to tenotomy

Tenotomy is a commonly encountered clinical entity, whether traumatic or iatrogenic. This article reviews the response of skeletal muscle to tenotomy. The changes are subdivided into molecular, architectural, and functional categories. Architectural disruption of the muscle includes myofiber disorganization, central core necrosis, Z-line streaming, fibrosis of fibers and Golgi tendon organs, changes in sarcomere number, and alterations in the number of membrane particles. Molecular changes include transient changes in myosin heavy chain composition and expression of neural cell adhesion molecule (NCAM). Functionally, tenotomized muscle produces decreased maximum tetanic and twitch tension. Alterations in normal skeletal muscle structure and function are clinically applicable to the understanding of pathological states that follow tendon rupture and iatrogenic tenotomy.