Use of Posterior Fixation Sutures (Myopexy) to Expand Binocularity: Indications and Limitations

Purpose: Intractable diplopia is not a rare complication of either paretic or restrictive limitation in extraocular motility related to skull base pathology and surgery. The primary goal of muscle surgery for rehabilitation is to achieve binocularity in primary position and down-reading gaze. To maximize the area of binocular single vision fields, however, patients may be treated with surgery to limit the motility of the better moving eye to match the involved eye. The posterior fixation suture introduced by Cuppers is an effective means of limiting motility.

Methods: A retrospective review of 43 patients undergoing 44 posterior fixation procedures was performed at the University of Virginia over a 13-year period. Patients were assessed quantitatively with Hess screen and binocular single-vision fields.

Results: There were a total of 26 females and 17 males between 14 and 88 years of age, with a mean age of 58 years. The most common cause of paretic limitation in motility and diplopia was the presence of skull base tumors (meningiomas in nine and pituitary tumors in two), with additional malignant tumors and a midbrain glioma. Four patients had aneurysms and two had carotid cavernous fistulae. Additional etiology included trauma in 11 patients, and 1 patient had a restrictive strabismus secondary to inflammation and infection following surgery for fibrous dysplasia. The most common muscle involved was the medial rectus (21 cases) followed by the inferior rectus in 12, the lateral rectus in 10, and the superior rectus in 1. Two patients required repeat procedures. One patient had inadequate follow-up, one patient continued to wear an occluder over one eye to avoid diplopia, and one patient was considered a failure even though the area of binocularity remained no worse. Only four patients had no diplopia at all, but most patients had expansion of binocularity so that double vision occurred only in extreme eccentric gaze.

Conclusions: Posterior fixation myopexy is a useful technique for expanding binocularity in patients with persistent diplopia secondary to cranial nerve palsies and restrictive strabismus often following skull base surgery.