Management of VIth nerve palsy--avoiding unnecessary surgery.

Unresolved VIth nerve palsy that is not adequately controlled by an abnormal head posture or prisms can be very suitably treated by surgery. It is however essential to differentiate partially recovered palsies, which are amenable to horizontal rectus surgery, from unrecovered palsies, which must be treated initially by a vertical muscle transposition procedure. Botulinum toxin is a valuable tool in making this distinction. It also facilitates full tendon transposition in unrecovered palsies, which appears to produce the best functional outcome of all the transposition procedures, with a reduction in the need for further surgery. A study of the surgical management of 12 patients with partially recovered VIth nerve palsy and 59 patients with unrecovered palsy provides clear guidelines on how to attain a successful functional outcome with the minimum amount of surgery.