An Orbital Approach to Superior Oblique Myokymia: Superior Oblique Myectomy and Trochlear Resection

We describe the outcomes and long-term follow-up of treatment with anterior orbitotomy with superior oblique myectomy and trochlear resection for superior oblique myokymia.

Single-center case report and long-term follow-up of 3 previously published cases of superior oblique myokymia treated with superior oblique myectomy and trochlear resection. Previously reported patients were contacted for long-term follow-up. A fourth patient's complex clinical course is detailed. The surgical procedure is described and contrasted with alternative approaches.

Four patients with refractory oscillopsia were treated. Symptom duration before presentation to the authors ranged from 10 to 22 years. All 4 patients had failed medical therapy; 3 of 4 had recurrent myokymia after prior superior oblique tenectomy; 1 of 4 had persistent symptoms despite 3 transcranial microvascular decompressions. After superior oblique myectomy and trochlear resection, all 4 patients reported sustained, complete resolution of oscillopsia in postoperative follow-up of 22, 17, 16, and 2 years. Three of 4 patients did not require additional strabismus surgery. Three of 4 patients reported mild postsurgical supra- and infratrochlear hypesthesia but deemed the symptoms not bothersome.

Superior oblique myectomy and trochlear resection is a surgical option for patients with superior oblique myokymia unresponsive to, or intolerant of, medical therapy. It can be used if superior oblique tenectomy fails, or it can be considered as primary surgical management. Further strabismus surgery may be required after this procedure. If used primarily, compensatory inferior oblique weakening should be planned, as it is following primary superior oblique tenectomy. In our view, the orbital approach is preferable to transcranial microvascular decompression.