Isolated Total Rupture of Extraocular Muscles

Management of traumatic incomplete lacerating rectus muscle injuries using multimodal imaging approach (ASOCT and CT/MRI)

Purpose: To describe the pathophysiology, importance of multimodal imaging approach, and the clinical outcomes of incomplete lacerating rectus muscle injuries. Methods: A retrospective review was conducted to identify patients with ocular deviation secondary to rectus muscle injuries. Between 2019 and 2022, a total of 30 patients were identified, amongst whom eleven patients had incompletely lacerated rectus muscles (secondary to penetrating adnexal trauma and sino-orbital surgeries). Patients' demography, nature of injury, computed tomography/magnetic resonance imaging, anterior segment optical coherence tomography features, intra-operative findings, and post-operative outcomes were reviewed. Results: The mean age of 11 patients was 31.36 ± 14.38 years. All patients had external trauma which severed the muscle in its anterior portion. Five patients had isolated inferior rectus muscle injury (45.45%), three had inferior and medial rectus muscle injuries together (27.27%), two had isolated lateral rectus muscle injury (18.18%), and one remaining patient had isolated medial rectus muscle injury (9.05%). In ten patients (90.90%) CT/MRI revealed features suggestive of muscle injury, however details with respect to muscle insertion and scleral course were lacking. In this difficult scenario, ASOCT filled these lacunae in nearly 90% of the patients by providing surgically useful details. Moreover, when CT/MRI-ASOCT imaging features were combined, the management and outcomes were even more predictable. Conclusions: Penetrating rectus muscle injuries can be better identified as incompletely lacerated muscle using multimodal imaging approach. This simple image correlation process customizes the treatment approach and hence the clinical outcomes.

Traumatic rupture of the inferior rectus muscle: case report and review of the literature

Traumatic inferior rectus muscle rupture secondary to blunt injury in the absence of associated orbital or ocular fractures or injury is rarely encountered, and there are limited published reports on subsequent surgical repair. We present the case of a 74-year-old man with complete inferior rectus transection following a fall with facial strike. A computed tomography scan of the face was unremarkable. Surgical exploration and repair of the muscle was performed by hooking the inferior oblique muscle to identify the inferior rectus muscle. Subsequent strabismus surgery was performed for residual binocular diplopia, resulting in excellent anatomic and visual outcomes and postoperative ocular alignment.

Simplification of the complex: Successful management of large-angle exodeviation after endoscopic sinus surgery

PURPOSE

To report the clinical characteristics and successful management of large-angle exodeviation due to medial rectus muscle (MR) transection incurred during endoscopic sinus surgery (ESS).

METHODS

The medical records of 5 consecutive inpatients with MR complete transection following ESS resulting in large-angle paralytic exodeviation between November 2014 and June 2021 were reviewed. The type of muscle injury, clinical characteristics, surgical procedure and dosage, and long-term outcomes were evaluated.

RESULTS

All 5 patients manifested exodeviations of 72 PD to >133 PD with no adduction capacity (graded -4); all of them had proven orbital trauma and complete MR transection with a ≥20 mm distal (globe attached) stump based on CT scans and/or MRI imaging. They underwent a supra-maximal recession (10-12 mm) of the lateral rectus and resection (10-15 mm) of the medial rectus on the affected eye. At least 1 year (1 to 5 years) following the corrective surgery, the patients still maintained orthophoria or had a small angle of exotropia (≤ 8 PD) in primary gaze with successful fusion, and 3 of them (Case 3, 4, and 5) exhibited a certain degree of stereopsis. In addition, appreciable adduction occurred (graded -1 to -3).

CONCLUSIONS

A supra-maximal recession/resection shows favorable outcomes in patients with proven complete transection MR with a ≥20 mm distal (globe attached) stump. It can help to achieve good ocular alignment and even yield improvements in adduction over time.

Temporalis Fascia for the Management of Medial Rectus Damage Secondary to Endoscopic Sinus Surgery: A Case Report

Purpose:

To report a challenging case of medial rectus (MR) damage secondary to endoscopic sinus surgery (ESS).

Methods:

A 37-year-old woman presented with diplopia, exotropia, and adduction deficit of the right eye due to the right MR injury secondary to the ESS.

Results:

As a stepwise approach, she respectively underwent repairing of the damaged MR plus ipsilateral lateral rectus recession, half-tendon vertical rectus transposition to the MR insertion, and eventually nasal globe fixation with temporalis fascia that ultimately provided a single vision in the primary position with orthophoria.

Conclusions:

Re-establishment of an acceptable field of a single binocular vision in the context of iatrogenic MR injury is challenging and often requires multiple step-wise operations. Temporalis fascia is a safe and strong autogenous material, which can be used for globe fixation in this setting.

Inferior Rectus and Inferior Oblique Muscle Transections with Medial Rectus Muscle Partial Avulsion, following Metal Hook Injury

Avulsion or transection of three extraocular muscles following trauma is a rare finding, and there are few case reports and series discussing the approach to surgical repair. The authors report a case of a penetrating metal hook injury resulting in partial avulsion of a medial rectus muscle and transection of the inferior rectus and inferior oblique muscles. This case highlights the importance of identification and primary repair of a complete inferior rectus muscle transection and a partial medial rectus muscle avulsion with an excellent functional outcome.

Aetiology, clinical features and surgical outcomes of isolated medial rectus palsy

IMPORTANCE

Isolated medial rectus palsy is extremely rare in clinical practice.

BACKGROUND

To report demographics, aetiology, clinical findings, imaging features and surgical outcomes in patients with isolated medial rectus palsy.

DESIGN

Retrospective study.

PARTICIPANTS

All patients treated for isolated medial rectus palsy at Zhongshan Ophthalmic Center, Sun Yat-sen University, between September 2003 and March 2019.

METHODS

Review of patient records.

MAIN OUTCOME MEASURES

Aetiology, clinical findings, imaging features and surgical outcomes.

RESULTS

A total of 32 patients (22 males, 10 females) were included. Mean age was 33.19 ± 19.78 years. The right eye was involved in 17 patients, the left eye was involved in 14 patients, and both eyes were involved in one patient. The most common causes were iatrogenic injury (43.75%), followed by trauma (37.50%) and congenital (18.75%). The most common clinical findings included outward deviation, diplopia and limited adduction. Six patients showed combined small-angle vertical strabismus, and 10 patients experienced a scale of -1 motility defect in other directions. After individualized strabismus surgery, preoperative exotropia of 60 ± 25 prism diopters (PD) was significantly reduced to 12 ± 13 PD (t = 10.938, P < .0001). Ocular motility improved in 21 patients, and five patients achieved normal ocular motility. Successful correction was obtained in 20/32 (62.50%) patients, with under-correction in 12/32 (37.50%) patients. Twenty-eight patients had only one surgery, three patients had two surgeries and one patient had three surgeries.

CONCLUSIONS AND RELEVANCE

The most common cause of isolated medial rectus palsy was local injury. Satisfactory results were obtained after individualized surgical interventions based on personalized preoperative evaluations.

Inferior Oblique Entrapment After Orbital Fracture With Transection and Repair

Extraocular muscle (EOM) entrapment with resulting reduction in motility and diplopia is a known complication of orbital fractures. Less commonly, transection of the EOMs due to trauma, iatrogenic injury, or intentional myotomy may lead to persistent diplopia. The inferior oblique (IO) is often encountered during orbital surgery along the medial wall and floor, and may be disinserted to aid in visualization. The authors present a case of IO entrapment which occurred during zygomaticomaxillary fracture reduction. Intraoperatively, an IO transection was performed and the muscle was reattached within the orbit. Postoperatively, the patient did not develop diplopia or motility disruption. This technique may provide a useful solution to an unusual problem during orbital fracture repair.

What decides the nature of extraocular muscle injury? The probable mechanism of flap tear and rupture

The assessment of nature and the extent of extraocular muscle injuries during initial visit in ocular emergencies is of paramount importance to avoid/minimize the subsequent need for strabismus surgery. Based on our experience in managing acute globe and orbital injuries and cases of strabismus, we propose the probable mechanism involved in the occurrence of extraocular muscle flap tear and a complete rupture of the muscle. During high-velocity injuries when the forces are equally transmitted along the orbital bony framework and the globe, then due to differential shearing forces created between the global and the orbital fibres leads to a flap tear. In the second scenario, if the forces are only directed along the bony framework, then the globe continues to be in continuous motion leading to increased tension between the muscles and the globe. Thus the weaker portions between these two structures are at risk of complete separation, that is along the insertion of muscle onto the globe or the musculotendinous portion.

Establishment of an acute extraocular muscle injury model in cats

AIM

To describe an acute extraocular muscle injury model in cats.

METHODS

Seventy-two cats were randomly divided into 6 groups (12 cats per group). Cats' left lateral recti were clamped using a surgical needle holder with a clamping strength of 2 (Groups A and D), 4 (Groups B and E) and 6 kg (Groups C and F). The right lateral recti were treated as controls. On the 4th and 7th days, hematoxylin eosin (HE) staining, immunohistochemical staining for proliferating cell nuclear antigen (PCNA), muscle force measurements and ocular alignment changes were performed to evaluate the extent of injuries.

RESULTS

The morphological changes were graded as mild, moderate or severe by HE staining in all experiment groups. PCNA immunohistochemical staining indicated repairment of muscle fibers in the damaged area. On the 4th and 7th days after clamping, the injured lateral muscle exhibited an elevated threshold for electric stimulation. The muscle forces among groups 2, 4 and 6 kg injury at 4d (Groups A, B and C) were statistically significant (P<0.05), but no significant differences were noted among groups 2, 4 and 6 kg injury at 7d (Groups D, E and F) (P>0.05), respectively. In addition, medial deviation in ocular alignment was also present to various degrees in all groups.

CONCLUSION

A cat model of acute extraocular muscle injury can be established by rectus clamping. Different clamping strengths can make different degrees of muscle injury. This model may help the future study in the acute extraocular muscle injury.

Surgical repair of traumatic isolated inferior rectus muscle avulsion

PURPOSE:

To report our experience in the management of avulsion of the inferior rectus muscle.

METHODS:

We describe the approach we have used for surgical repair of isolated avulsion of the inferior rectus muscle in two patients who suffered orbital trauma.

RESULTS:

In both cases, the proximal portion of the inferior rectus muscle was located successfully by the generated muscle force duction test and sutured back into its original insertion point. Infraduction was normal and orthotropia was present in all directions of gaze during 1 year of postoperative follow-up in both cases. These favorable outcomes are attributed in part to the inferior rectus muscle pulleys system and the natural history of this type of injury, which allows the lost proximal portion to be identified by generated muscle force duction test.

CONCLUSION:

Generated muscle force duction test can be used to locate the proximal portion of a lost inferior rectus muscle and restore its function in patients with traumatic avulsion injury involving an extraocular muscle.

Suture Fixation of Globe to the Orbital Wall for Complicated Strabismus

PURPOSE

The aim of this study was to observe the surgical outcomes of suture globe fixation to the orbital wall for patients with complicated strabismus.

MATERIALS AND METHODS

The medical records of patients with complicated strabismus who were treated at the Zhongshan Ophthalmic Center of Sun Yat-sen University, Guangzhou, China, from January 2010 to June 2015 were retrospectively reviewed. Routine strabismus surgery was not possible in these cases. Eyes were anchored to the orbital wall by simple strong anastomosis of the extraocular muscle and orbital wall tissues using silk suture, which resulted in slight overcorrection of the ultimate ocular position after anchoring.

RESULTS

Eight patients with complicated strabismus received suture globe fixation to the orbital wall in our hospital, including 4 cases of strabismus that occurred after severe orbital injury and/or fracture repair, 2 cases of medial rectus rupture after endoscopic sinus surgery, 1 case of complete third nerve palsy, and 1 case of complete sixth nerve palsy. Five patients were male and 3 female, with age ranging from 20.0 to 57.0 years (mean = 38.1 years). The right eyes were involved in 7 cases and the left in 1 case. Five cases underwent globe fixation to the medial orbital wall, 2 cases to the lateral orbital wall, and 1 case to the inferior orbital wall. After at least 6 months follow-up, preoperative horizontal deviation of 60.625 ± 27.443 prism diopter (PD) (mean ± standard deviation) was reduced to 16.250 ± 12.464 PD. The vertical deviation was reduced from 15.000 ± 12.313 PD to 7.5 ± 5.244 PD. Two patients achieved orthophoria, and although the remaining 6 patients showed some residual strabismus (undercorrection), their appearance was significantly improved. No other surgical complications occurred in these cases.

CONCLUSION

Suture fixation of the globe to the orbital wall by flesh-to-flesh anastomosis of the extraocular muscle and orbital wall tissues achieved a desirable surgical result for complicated strabismus.

Pulled-in-two syndrome: a multicenter survey of risk factors, management and outcomes

BACKGROUND

Pulled-in-two syndrome (PITS) is a serious complication of strabismus surgery that occurs when an extraocular muscle ruptures under tension. The purpose of this study was to establish a database of PITS patients to identify risk factors and management of PITS.

METHODS

Strabismus surgeons from around the world contributed cases of PITS through an online survey. Risk factors, management, and outcomes were identified.

RESULTS

A total of 40 cases of PITS from 29 physicians in 6 countries were collected. The most commonly involved muscles were the medial rectus (18/40 [45%]) and the inferior rectus (17/40 [43%]). The most commonly identified risk factors were previous ocular surgery (11/40 [28%]) and cranial nerve palsy (11/40 [28%]). Advanced age was also a significant risk factor, with 28/40 (70%) of reported patients being ≥50 years of age. In most cases the muscle was found and reattached to the globe (28/40 [70%]). The muscle was lost in 12 cases (30%). Half of these patients received a transposition surgery; the other half were followed by observation.

CONCLUSIONS

Our data suggests that strabismus surgeons might encounter one case of PITS approximately every 10 years. Major risk factors for PITS appear to be changes in the extraocular muscle due to cranial nerve palsy, prior surgery, and advancing age. The preferred management for PITS is surgical recovery and reattachment of the muscle; however, if the muscle is lost, transposition surgery or observation are common forms of management.