Abstract Listings 2024

Purpose

A 17-year-old female presented with a 9-month history of progressive left proptosis, afferent pupillary defect with preserved vision and optic nerve head edema. Orbital MRI demonstrated a large, well defined, oval intraconal mass, hypointense on T1, mixed intensities on T2, with brisk enhancement including internal flow voids, representing vascularity. Initial impression was of a vascular lesion such as a solitary fibrous tumor (SFT).

Methods

Surgical video

Results

Surgical debulking involved lateral, medial and inferior orbitotomy for optimal exposure and safe tumor removal. Piecemeal debulking denoted a grayish, rubbery tumor, ruling out SFT. Histopathology indicated a schwannoma. One week postoperatively, the patient had near complete horizontal movement limitation and a dilated pupil. Three months postoperatively, ocular movements were fully intact, and pupil size significantly improved. Optic nerve edema and axial globe proptosis resolved completely.

Conclusion

This transient postoperative ocular dysmotility can be attributed to neurapraxia following mechanical intraoperative manipulation. Neurapraxia, the mildest form of traumatic peripheral nerve injury (PNI), is characterized by focal segmental demyelination without disruption of axon continuity. Nerve conduction impairment and transient weakness may follow traumatic or operative compression of the nerve. Local anesthesia can also cause neurapraxia through vasoconstriction-induced ischemia and chemical nerve injury. Transient dilated pupil after orbital surgery may occur secondary to neurapraxia of parasympathetic postganglionic fibers. We found only one case report discussing postoperative extraocular muscle neurapraxia as a complication of orbital surgery.7 Neurapraxia has an excellent prognosis, and complete recovery due to axon remyelination is typical within days to weeks, as was observed in our patient.

Additional Authors

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