Slipped, severed, torn and lost extraocular muscles

Study 3: Anterior segment optical coherence tomography-guided surgical approach in slipped medial rectus muscle

Purpose

To discuss the novel swept-source anterior segment optical coherence tomography (SS-ASOCT)-guided surgical approach in slipped medial rectus muscles.

Methods

Prospectively (between February 2020 and July 2022), six patients with a clinical suspicion of slipped medial rectus muscle were recruited. After complete ophthalmic and orthoptic evaluation, the missing medial rectus muscle is screened using Anterior Segment Optical Coherence Tomography (ASOCT). In presence of a traceable muscle, its morphology, depth, and distance from a fixed anatomical landmarks were noted; in its absence, the status of other recti was noted. Intraoperatively, the features were confirmed and the intended intervention was performed.

Results

The mean age of six patients was 25.66 ± 9.72 years, two with surgical trauma and four with penetrating trauma (66.66%). In five patients, the ASOCT traced the slipped medial rectus muscle successfully (83.33%); intraoperatively, the same was confirmed (within 1-2 millimeters) with favorable outcomes. ASOCT made a significant contribution in all subjects by reducing the number of interventions and muscle surgeries.

Conclusions

In eyes with slipped medial rectus muscle, especially those which are within a finite distance from the angle can be traced using ASOCT. This approach impacts the outcomes in many ways.

Pulled-in-two syndrome in strabismus surgery for congenital fibrosis of the extraocular muscles

Purpose: The aim of this study is to present six cases of pulled-in-two syndrome (PITS) in strabismus surgeries and to discuss our prevention and management strategies. Methods: This is a retrospective study presenting cases of PITS during strabismus operations. The medical records of the subjects who underwent operation in the strabismus unit of Beyoglu Eye Training and Research Hospital were reviewed retrospectively, from January 2000 till March 2022. Detailed ophthalmological examination records and angle of deviation were noted. Results: A total of six cases (four males and two females) with a mean age of 37.2 ± 28.0 (min 9-max 71) years were included in this study. All of the cases had congenital fibrosis of extraocular muscles (CFEOM). The most commonly involved muscle was medial rectus (83%). Majority of cases (67%) were adults. In all cases, the muscle was found and reattached to the globe. No patients had diplopia after surgery. Conclusion: PITS is a rare complication that can be seen during strabismus surgeries, and CFEOM patients are in the risk group. Therefore, surgeons should be cautious and prepared in risky patients to be able to manage this complication.

Rescue of exotropia subsequent to pulled-in-two syndrome of the medial rectus muscle occurring during surgery for high myopic strabismus fixus: A case report

RATIONALE

Pulled-in-two syndrome is one of the significant complications of strabismus surgery. This study aimed to report a case of pulled-in-two syndrome of the contractured medial rectus muscle (MR) that occurred during strabismus surgery for strabismus fixus due to high myopia, and to describe a rescue of this complication.

PATIENT CONCERNS

A woman in her 60s presented to our Ophthalmology Department with the main complaint of unilateral high myopia and severe myopic strabismus fixus. Esotropia exceeded 45° and hypotropia exceeded 15° in her right eye in the Hirschberg test. Right eye duction was markedly limited in every gaze direction. Orbital magnetic resonance images showed rupture of the superior rectus to lateral rectus band ligament and lengthening of the distance between the SR and LR muscles in the right eye.

DIAGNOSIS

Due to the patient's ophthalmic examination and imaging results, she was diagnosed with high myopic strabismus fixus.

INTERVENTIONS

We performed MR recession and Yokoyama surgery to correct right eye hypoesotropia. In the MR recession procedure, pulled-in-two syndrome (MR muscle tear) occurred. Thus, no additional procedure was performed on the MR. After the surgery, she presented 45 prism diopter exotropia and 18 prism diopter residual right hypotropia in a Krimsky test. We performed a second surgery, combining MR muscle advancement and inferior rectus (IR) muscle recession, 3 months after the first surgery.

OUTCOMES

One and a half years after the second surgery, she presented exotropia of 14 prism diopters without hypotropia in the Krimsky test and was satisfied with her ocular position and improved motility.

LESSONS

We experienced pulled-in-two syndrome in a case with severe myopic strabismus fixus and achieved a good outcome by performing additional surgery 3 months later, in which the lost MR muscle was advanced. This case underscores that, if the lost muscle cannot be found during surgery, one should maintain composure and perform a reoperation a few months after the initial surgery, if necessary. This case report can aid in making rescue treatment decisions when pulled-in-two syndrome occurs.

Medial rectus muscle loss: Is immediate lateral rectus disinsertion a solution? A case report with review of the literature

Purpose

To report a case of medial rectus (MR) muscle loss during the strabismus surgery with a late successful management and review of the literature.

Methods

The left MR was lost during resection in a 14-year-old girl who had undergone strabismus surgery elsewhere. The surgeon disinserted the antagonist lateral rectus (LR) muscle in the same session following unsuccessful attempts to retrieve the lost muscle. She was referred to our clinic two months later with a large angle exotropia and a complete lack of adduction. We performed a half-tendon transposition of vertical rectus muscles to the MR insertion and attached the residual fibers of the LR to the orbital periosteum.

Results

She was orthotropic after the surgery and remained stable until 6 months with a significant improvement of the adduction.

Conclusions

Simultaneous LR disinsertion is not a solution for MR loss. Half-tendon transposition of the vertical recti to the original insertion of the lost MR and periosteal fixation of the LR are good options as a second-stage operation in patients with MR loss during strabismus surgery.

Spontaneous Reattachment of the Medial Rectus After Free Tenotomy

PURPOSE

To assess the outcome of free tenotomy of the medial rectus muscle in post-natal monkeys.

METHODS

The medial rectus muscle was disinserted in both eyes of 6 macaques at age 4 weeks to induce an alternating exotropia. After the impact on the visual cortex and superior colliculus was investigated, the animals were examined post-mortem to assess the anatomy of the medial rectus muscles.

RESULTS

After tenotomy, the monkeys eventually recovered partial adduction. Necropsy revealed that all 12 medial rectus muscles had reattached to the globe. They were firmly connected via an abnormally long tendon, but at the native insertion site.

CONCLUSIONS

Medial rectus muscles are able to reattach spontaneously to the eye following free tenotomy in post-natal macaques. The early timing of surgery and the large size of the globe relative to the orbit may explain why reinsertion occurs more readily in monkeys than in children with a lost muscle after strabismus surgery. [J Pediatr Ophthalmol Strabismus. 2018;55(5):335-338.].

Localizing the Lost Rectus Muscle Using the Connective Tissue Framework: Revisiting the Tunnel Technique

PURPOSE

To describe a technique for localizing a lost rectus muscle during strabismus or retinal surgery or following trauma.

METHODS

In this single center, retrospective chart review, 5 patients were identified between January 2012 and June 2016 with a lost rectus muscle; 3 during strabismus surgery and 2 post trauma. The inclusion criteria included a lost rectus muscle during strabismus surgery, or a disinserted/lacerated rectus muscle following ocular/orbital trauma. The primary outcome measure was successful reattachment of the rectus muscle.

RESULTS

The lost rectus muscle was identified in each patient and reattached to the globe by gently applying traction anteriorly at the conjunctiva/Tenon edge using double-pronged skin hooks and following the path of the rectus muscle through its Tenon capsule tunnel where it remained attached by suspensory ligaments. There was no instance where orbital fat was obscuring or blocking the view of the lost rectus muscles. There were no other complications associated with the procedure.

CONCLUSIONS

The authors describe a simple and effective method in 5 patients to localize a lost rectus muscle based on knowledge of the orbital connective tissue framework.

Slipped extraocular muscles: characteristics and surgical outcomes

OBJECTIVE

To study the frequency and characteristics of slipped extraocular muscles after strabismus surgery and report the postoperative outcomes longitudinally.

DESIGN

Retrospective chart review.

PARTICIPANTS

Electronic medical records of 493 patients who underwent strabismus surgery and were found to have a slipped muscle intraoperatively were reviewed.

METHODS

Records were retrieved and operative reports were screened for the presence of slipped muscles. Data pertaining to the eye examination and surgery were collected, including vision, ocular motility in all positions, duction limitations, slipped muscle, empty sheath length, amount of slippage, amount of advancement, and amount of recession of the antagonist muscle.

RESULTS

Twelve patients (mean age 29.1 ± 6.4 years; 5 males) were found to have 15 slipped medial rectus muscles. Average amount of slippage was 15.7 ± 2.0 mm; from limbus empty sheath length was 5.9 ± 1.9 mm. Average preoperative deviation was 32.2 ± 10.0 prism diopters (PD) exotropia. Mean follow-up after corrective surgery was 13.3 months (1 week to 42 months). Four patients were transiently overcorrected postoperatively (7.0 ± 7.0 PD esotropia). The rest had mean residual exotropia of 13.5 ± 9.2 PD with a change of 26.6 ± 10.3 PD from baseline (p < 0.001). Intraoperative mean muscle movement was 10.3 ± 2.2 mm with a mean postoperative change of 2.6 PD for each 1 mm of muscle advancement. There was no significant increase over time in the postoperative angle of deviation during all follow-up periods except for 1 patient who was re-explored after 4 years.

CONCLUSIONS

Slipped muscle should be suspected in the presence of limited ductions and consecutive deviations after strabismus surgery. A change of 2.6 PD for every 1 mm of medial rectus muscle advancement was observed and maintained over time.

Intraoperative Findings in Consecutive Exotropia with and without Adduction Deficit

PURPOSE

Consecutive exotropia may be associated with limited adduction, which has been reported to be caused by 1 or more anatomic abnormalities of rectus muscles or their insertions. We studied the relative frequency of grades of adduction deficit and the relative frequency of abnormal anatomic findings.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Patients undergoing surgery for consecutive exotropia.

METHODS

Preoperative duction deficits were graded on a -5 (severe limitation) to 0 (normal) scale. Operative reports were reviewed to classify intraoperative factors: (1) medial rectus muscle attachment type (normal, abnormal [slipped or stretched scar], attached to pulley, behind pulley, or mixed [a tenuous normal attachment, but with muscle fibers also attached to the pulley or behind the pulley]), (2) medial rectus muscle distal fiber location (millimeters from original insertion), and (3) lateral rectus muscle tightness (normal, mild restriction, moderate restriction).

MAIN OUTCOME MEASURES

Relationship of grade of adduction deficit to each intraoperative factor.

RESULTS

Of 143 eyes, 124 (87%) had an adduction deficit. Eyes with abnormal (n = 23), pulley (n = 9), behind pulley (n = 8), or mixed (n = 7) attachments had worse adduction deficits than normal attachments (n = 96; P < 0.02). There was a significant correlation between distal medial rectus muscle fiber location (0-19.5 mm recessed) and grade of adduction deficit (P < 0.0001). Eyes with mild or moderate lateral rectus muscle tightness on forced duction testing (n = 48/143 eyes) had worse adduction deficits than eyes without tightness (P < 0.001). Nevertheless, despite overall correlation, there was considerable individual variability. For example, for -1 and -2 adduction deficits, medial rectus muscle attachment could be at the pulley, behind the pulley, or include the pulley (19/87 eyes [22%]), and the lateral rectus muscle was tight in 36 of 87 eyes (41%).

CONCLUSIONS

Adduction deficits are common in patients with consecutive exotropia. Overall, more severe preoperative adduction deficits are associated with medial rectus muscle insertion abnormalities and abnormal forced ductions, but frequently there are exceptions. Severe medial rectus muscle insertion abnormalities, including lost muscles, may be found despite mild preoperative adduction deficits.

The Hook and Release Technique During Enucleation Surgery

PURPOSE

To describe the results and potential benefit of direct muscle release from the globe during enucleation surgery without identifying sutures in the rectus muscle insertion sites, a technique referred to as the hook and release technique.

METHODS

Single center, retrospective chart review of patients who underwent enucleation with direct removal of the rectus muscles without identifying sutures in their insertion sites between January 2011 and September 2015 was carried out. The inclusion criteria were primary enucleation without previous strabismus surgery, retinal detachment surgery, or orbital surgery that entered the fibrous connective tissue framework. Forty charts of enucleated patients that had direct release of their extraocular muscles without identifying sutures before releasing them from the globe were identified and reviewed. The primary outcome measure was intraoperative or immediate postoperative complications. This retrospective chart review was performed with research ethics board approval and in compliance with the Declaration of Helsinki.

RESULTS

Data show that following the hook and release technique, the rectus muscles were easily located and reconnected to the orbital implant wrap. The oblique muscles were not reattached. In each of the 40 patients, the 4 rectus muscles were easily located by gently applying traction anteriorly at the conjunctiva/Tenons' edge using double-pronged skin hooks. There was no instance of a lost or slipped muscle following the hook and release technique.

CONCLUSION

The hook and release technique is a simple and efficient method to remove the 4 rectus muscles from the globe and still easily locate them. They are not "lost" and do not "slip out of position" but held in place by the orbital connective tissue framework and the extraocular muscle pulley system. This technique has been very helpful teaching resident staff how to do enucleation surgery as it avoids the more time consuming placement of double-armed locking sutures through the rectus muscle insertions and the potential risk of globe penetration while the muscles remain attached to the eye. If the surgeon desires to attach the muscles to the orbital implant, then sutures are passed after the eye is removed, thus eliminating the worry of globe penetration and avoiding accidentally cutting preplaced extraocular muscle sutures during the remaining enucleation procedure.

Isolated Total Rupture of Extraocular Muscles

Total rupture of extraocular muscles is an infrequent clinical finding. Here we conducted this retrospective study to evaluate their causes of injury, clinical features, imaging, surgical management, and final outcomes in cases of isolated extraocular muscle rupture at a tertiary center in China. Thirty-six patients were identified (24 men and 12 women). Mean age was 34 years (range 2-60). The right eye was involved in 21 patients and the left 1 in 15. A sharp object or metal hook was the cause of this lesion in 16 patients, sinus surgery in 14 patients, traffic accident in 3 patients, orbital surgery in 2 patients, and conjunctive tumor surgery in 1 patient. The most commonly involved muscles were medial (18 patients) and inferior rectus muscles (13 patients). The function of the ruptured muscles revealed a scale of -3 to -4 defect of ocular motility and the amount of deviation in primary position varied from 10 to 140 PD (prism diopter). Computerized tomography (CT) confirmed the presence of ruptured muscles. An end-to-end muscle anastomosis was performed and 3 to 5 mm of muscle was resected in 23 patients. When the posterior border of the injured muscle could not be identified (13 patients), a partial tendon transposition was performed, together with recession of the antagonist in most patients, whereas a recession of the antagonist muscle plus a resection of the involved muscle with or without nasal periosteal fixation was performed in the remaining patients. After an average of 16.42 months of follow-up an excellent result was achieved in 23 patients and results of 13 patients were considered as a failure. In most patients, the posterior border of the ruptured muscle can be identified and an early surgery can be performed to restore function. Alternatively, a partial tendon transposition should be performed. When muscular rupture is suspected, an early orbital CT is required to confirm this possibility, which can then verify the necessity for an early surgical intervention.

Instructions to Patients and Families Following Strabismus Surgery

PURPOSE

To analyze postoperative instructions provided to patients and families after strabismus surgery.

METHODS

In April 2012, a 12-question electronic survey was sent to all members of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) regarding their instructions to patients undergoing strabismus surgery. The questions specifically addressed patients’ daily activities, such as their resumption of school and work, sports, swimming, normal showering and bathing, and contact lens use.

RESULTS

One hundred two responses were completed; 96% were from pediatric ophthalmologists regularly performing strabismus surgery. Participation was greater by North American members (86%) and respondents with more than 10 years of experience (75%). Fifty percent of the respondents advised patients to resume normal showering and bathing 24 hours after surgery. Conversely, respondents recommended that children wait 3 to 4 days before resuming schoolwork (52%) and at least 2 weeks before playing in a sandbox (47%). Furthermore, respondents indicated that patients should refrain from participating in sports-related activities for at least 1 week (43%) and should not go swimming for at least 2 weeks (56%). Finally, 47% advised their patients not to wear contact lenses for 2 weeks after surgery.

CONCLUSIONS

Overall, the responses indicated a high regard among AAPOS members for promoting normal healing and prevention of infection and other postoperative complications; however, certain trends, such as the recommendation regarding normal showering, may intimate a lack of further infection prevention.

Surgical results of the slipped medial rectus muscle after hang back recession surgery

AIM

To analyze the surgical results of a slipped medial rectus muscle (MRM) after hang back recession surgery for esotropia.

METHODS

Twenty-one patients who underwent re-exploration for diagnosed slipped muscle after hang back recession surgery were included in this retrospective study. Dynamic magnetic resonance imaging was performed to identify the location of the slipped muscle. Ocular motility was evaluated with assessment with prism and cover test in gaze at cardinal positions. The operations were performed by the same consultant. Intraoperative forced duction test was performed under general anesthesia. The empty sheath of the slipped MRM was resected and the muscle was advanced to the original insertion site in all patients.

RESULTS

The average age of 21 patients who had consecutive exotropia with a slipped MRM at the time of presentation was 17.4±5.4y (5-50y). The average duration between the first operation and the diagnosis of the slipped muscle was 25mo (12 to 36mo). The mean follow up after the corrective surgery was 28mo. The mean preoperative adduction limitation in the field of action of the slipped muscle was -2.26 (ranging from -1 to -4). All patients had full adduction postoperatively.

CONCLUSION

The diagnosis of the slipped muscle should be confirmed during the strabismus surgery. The slipped muscle may be caused due to insufficient suture and excessive rubbing of the eye. When divergent strabismus is observed after the recession of the MRM, a slipped muscle should be considered in the differential diagnosis.

Retrieval of ruptured medial rectus muscle with an endoscopic endonasal orbital approach. A case report and indication for surgical technique

INTRODUCTION

Rupture of the extraocular muscle is extremely rare, and a traumatic event is especially uncommon. Although retrieval of an injured MRM is usually performed by an anterior approach by an ophthalmologist, missing muscles in the orbital retrobulbar space are sometimes difficult to identify. This is the first report to demonstrate direct muscle to muscle anastomosis by an endoscopic endonasal orbital approach by a single otolaryngologist.

CASE REPORT

A 67-year-old man presented with left medial rectus muscle (MRM) rupture due to a traffic accident 4 months after injury. The MRM was completely ruptured, and the muscle was repaired by an endoscopic endonasal orbital approach. After surgery, his eye abduction was improved in the primary position, and adduction ability was markedly restored on right gaze without diplopia.

CONCLUSIONS

Our endonasal endoscopic approach provides excellent access to the MRM in the orbital retrobulbar space and avoids a facial scar. We could suture both ends of the muscle together by an endonasal endoscopic approach and could obtain a good result without any complications.

Late correction for blow-out sequelae: transposition of a longitudinally transected inferior rectus muscle

A 45-year-old woman who had been operated for blow-out fracture, presented with a complaint of cosmetic concerns about her appearance. Orthoptic evaluation was notable for a left 35(∆) exotropia and 25(∆) hypertropia in primary position. Magnetic resonance imaging and the surgical exploration revealed a longitudinally transected left inferior rectus muscle. Transposition procedures which were carried out for left inferior and superior recti provided a good cosmetic result and satisfactory ocular alignment.

Severe complications of strabismus surgery

PURPOSE

To determine the type, incidence, and clinical outcomes of severe complications from strabismus surgery in the United Kingdom.

METHODS

Cases were identified prospectively through a national surveillance unit between September 1, 2008, and August 31, 2010. Questionnaire data were requested at the time of the complication recognition and at 6 months' follow-up. Outcome was graded I to V, with a poor or very poor outcome meaning either loss of corrected visual acuity or primary position double vision.

RESULTS

A total of 60 completed reports of adverse events and complications were received during the study period. During the same time approximately 24,000 strabismus surgeries were performed in the United Kingdom, yielding an overall incidence of 1 in 400 operations (95% binomial confidence, 1 per 333-500 operations). The most common reported complication was perforation of the globe (19 [0.08%]), followed by a suspected slipped muscle (16 [0.067%]), severe infection (14 [0.06%]), scleritis (6 [0.02%]), and lost muscle (5 [0.02%]). Overall, complications were reported in adults and children in equal numbers; however, scleritis was significantly more common in adults. A poor or very poor clinical outcome was recorded as 1 operation per 2,400.

CONCLUSIONS

This study provides an assessment of the overall risks associated with strabismus surgery in the United Kingdom. Complications with the potential for a poor outcome are relatively common, but the final clinical outcome is good in the majority of cases.