Subtenon injection of botulinum toxin for treatment of traumatic sixth nerve palsy.

PURPOSE: Subtenon injection of botulinum toxin may produce results similar to intramuscular injection of the medial rectus muscle for the treatment of acute traumatic sixth nerve palsy. This study was designed to evaluate the clinical efficacy of subtenon injection and to compare our results with those in previously published reports.

METHODS

During 3 years at a single institution, 13 patients with traumatic sixth nerve palsy of less than 6 months' duration were treated with subtenon injection of botulinum toxin. The deviation angles before and after injection were recorded. A distance esotropia of less than 10 prism diopters (PD) in the primary position or absence of diplopia at 3 months was defined as recovery.

RESULTS

Of the 13 patients treated, 11 (84.5%) had unilateral palsy and 2 (15.4%) had bilateral palsy. The average pre-injection deviation was 39.5 PD of esotropia, and the average post-injection deviation was 17.0 PD. Seven patients experienced recovery and regained binocular single vision; the overall recovery rate was 53.8% (unilateral, 63.6%; bilateral, 0%). Six patients did not recover and subsequently underwent strabismus surgery.

CONCLUSION

Patients with traumatic sixth nerve palsy treated with subtenon injection of botulinum toxin showed higher recovery rates than did most patients treated with conservative measures in published reports. The result of subtenon injection of botulinum toxin without electromyography (EMG) guidance was comparable to that obtained using EMG-guided intramuscular injection of botulinum toxin. Patients with unilateral palsy demonstrated a better recovery rate than did patients with bilateral palsy.