This German retrospective review evaluation compared rates of improvement and outcome criteria in a large cohort with 2 treatment branches for sixth nerve palsy. Recovery was defined as no diplopia in primary gaze, angle ≤10 prism dioptres and improved abduction deficit by 10 degrees. The review was from January 1987 to April 2022 and included 137 patients with sixth nerve palsy. The two groups were (1) conservative with monitoring with/without prisms or occlusion and (2) ipsilateral medical rectus BT injections with/without prisms or occlusion. Aetiologies for sixth nerve palsy included trauma, microvascular, neoplasm, idiopathic and other. Both groups were similar in demographics except for the affected eye. There were more longstanding palsies in group 1 and larger angle and abduction limitations in group 2. Abduction was graded as 0 (normal) to -7 (marked deficit). Adverse events for BT injections were reported for 62.9% in group 2 inclusive of vertical deviation, adduction deficit and ptosis. There was no difference in change of motility score between groups or rates of improvement in recovery for recent onset palsy. Both groups had recovery rates of 28.85%. A bias was found towards non-improvement for longstanding palsies. The conclusions of this study are that BT does not alter rates of recovery overall for recent cranial nerve palsies. Treatment with BT was more likely to be given for larger presenting angles of deviation and more severe abduction deficit. Conservative treatment was provided for those with lower levels of symptoms. Strabismus surgery was often needed for longstanding palsies as the eventual intervention. Improvement in angle and abduction limitation was better for the BT group even though overall rates of recovery were similar between groups.
BT vs. conservative treatment only for sixth nerve palsies
Reviewed by Fiona Rowe
An evaluation of 30 years’ experience in the use of botulinum toxin injections in the management of sixth nerve palsies.
CONTRIBUTOR
Fiona Rowe (Prof)
Institute of Population Health, University of Liverpool, UK.
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