Extraocular muscle injury during endoscopic sinus surgery: an ophthalmologic perspective

Abstract

Purpose The purpose of this study is to describe the clinical characteristics and treatment results of medial rectus muscle (MR) transection incurred during endoscopic sinus surgery. Methods This retrospective study included 16 patients with MR transection incurred during endoscopic sinus surgery between 1994 and 2015. The operative notes of the surgical procedure, the pattern of strabismus, the type of muscle injury, the type of corrective strabismus surgery, and the surgical outcomes were reviewed. Results Nine patients had partial resection of MR and seven patients had complete transection of MR, resulting from an injury incurred during endoscopic sinus surgery. Three of the nine patients with partial resection injury were initially diagnosed as complete resection and subsequently rediagnosed as partial resection in a review of the images during this study. Five of the nine patients with partial MR resection underwent only simple recession/resection surgery. Patients with complete MR transection underwent muscle transposition or globe fixation surgeries and often multiple operations were required. Conclusions The results of this study showed that the treatment strategies could vary depending on the nature of muscle injury. In cases with complete transection, muscle transposition or globe fixation surgeries are often required, with multiple operations. However, partial muscle resection with only simple recession/resection surgery shows a favorable outcome in many cases. The use of proper imaging techniques, a thorough review of the images with various planes, and close follow-up are important for determining the nature of the muscle injury.

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

“…This indicated that patients with congenital MRP often required strabismus surgery to correct their exotropia as performed by an ophthalmologist, whereas patients with MRP resulting from midbrain infarction are usually managed with drug therapy as administered by neurologists. Endoscopic sinus surgery and trauma (81.25%) were the most common causes of the lesions in our study, consistent with that of previously described 5‐14 . Extraocular muscle injury, especially of the medial rectus, is a rare complication of endoscopic sinus surgery.…”

“…The extremely rare incidence of isolated MRP has severely limited the availability of information on the aetiology, clinical findings, imaging features and therapeutic outcomes of this condition. Based on previous studies involving 59 cases, the most common causes for MRP included complications after endoscopic sinus surgery as observed in 38 (64.40%) patients, followed by trauma in 11 (18.64%), midbrain infarction in eight (13.56%), complications after strabismus surgery in one (1.70%) and medial rectus muscle disinsertion by scleral buckle in one (1.70%) patient 5‐14 . To our knowledge, it is the first time to review isolated MRP, not as a single case presentation.…”

“…Orbital CT or MRI has become valuable imaging tools for use in both the diagnosis and surgical plans for this condition. Park and Oh 13 suggested that MRI may be more effective to reveal the presence of damaged muscles than CT scans. Orbital imaging is useful in identifying the posterior border of the muscle 20 .…”

“…In extraocular muscle palsy, CN VI represents the most common type of paralytic strabismus, accounting for 33% to 63% of cases, followed by CN III palsy (22%‐41.2%) and CN IV palsy (11%‐36%) 1‐4 . Isolated medial rectus palsy (MRP) is extremely rare in clinical practice, with only 59 cases being reported in the English literature, often involving single case presentations 5‐14 . Possible aetiologies may include damage of the medial rectus nucleus or terminal branches of the oculomotor nerve serving only the medial rectus, or direct medial rectus muscle injury, such as orbital trauma or surgical complications of endoscopic sinus surgery.…”

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

“…MR is the most commonly lost muscle in strabismus surgery. MR loss has also been reported in other surgeries including retinal detachment repair, endoscopic lacrimal, or sinus procedures and orbital trauma repair 2, 3, 4. There is no intermuscular septum between the MR and the oblique muscles which makes the surgically lost MR difficult to retrieve 5…”