Thirty-four patients with acute
sixth nerve palsy and nine patients with acute
third nerve palsy were treated with
botulinum toxin injection to the antagonist, nonparalytic horizontal rectus muscle. In a control group of 52 patients with acute
sixth nerve palsy not treated with botulinum in the acute stage, only 16 (31%) recovered spontaneously and did not require surgery. Twenty-two of the 31 surviving patients who could be followed with acute
sixth nerve palsy had lateral rectus recovery and surgery was avoided. Four required prisms in their glasses to obtain fusion. Nine patients developed chronic
sixth nerve palsy and required surgery. In this group of acute
sixth nerve palsy patients, eleven were bilateral. Seven of these eleven developed chronic sixth nerve
paralysis, and required
strabismus surgery. This suggests the prognosis for recovery following botulinum treatment in cases of acute bilateral
sixth nerve palsy is not as good as in the unilateral cases.
Botulinum toxin treatment does not appear to be effective in chronic
sixth nerve palsy, as judged by results of treatment in one patient known to have a chronic
palsy. Nine of nine patients with acute
third nerve palsy had medial rectus recovery with fusion horizontally in primary gaze. None have required surgery. Only four of nine showed improvement in vertical rotations. The remaining five patients avoid
vertical diplopia by a compensatory chin position.
Botulinum toxin treatment of patients with acute sixth and
third nerve palsy appears beneficial. However, since some in this group of patients may recover spontaneously, a randomized, double-blind study may be necessary to more definitively determine the effectiveness of this
therapy.