Diagnostic use of botulinum toxin in patients with Duane syndrome

Duane syndrome is a difficult condition to treat. Patients and parents need to be informed that it will not resolve and it is not possible to create normal eye movements surgically. Botulinum toxin may be used to assess the likelihood of reducing the abnormal head posture and reducing the diplopia by increasing the field of binocular single vision. If results are favorable then surgery may be offered. This article is a retrospective review of patients with Duane syndrome treated with botulinum toxin using the toxin clinic database between 1980 and 2007.

Eighty-eight patients were identified, 48 females and 40 males. The average age at presentation was 29 years, range 5 to 68 years. The left eye was affected in 50 (57%) patients and 21 (24%) patients were affected bilaterally. The average angle was 28.6 +/- 18.4 Delta for the esotropic patients and 32.5 +/- 14.5 Delta for the exotropic patients. In 58 patients the medial rectus was injected, in 30 the lateral rectus.

As a result of the outcome of botulinum toxin, 41 (46.5%) patients proceeded to surgery; 12 (14%) continued with maintenance toxin. Forty-seven (53%) demonstrated a long-term reduction in deviation. Transient complications were ptosis in 11 patients and induced vertical deviation in 10.

This is the first study to explore the diagnostic role of botulinum toxin in Duane syndrome. It is a safe treatment that may also offer long-term benefits.