Session: Free papers Session III - Incomitant Strabismus

An Evaluation of 30 years’ Experience in the use of Botulinum Toxin Injections in the Management of Sixth Nerve Palsies.

Introduction

This service evaluation investigates botulinum toxin (BT) injections into the medial rectus muscle (MR) compared to conservative treatment in sixth nerve palsies. It aims to detect recovery rates and contribute to a more robust decision-making process.

Methods

Retrospectively files of adult patients with a sixth nerve palsy were reviewed. Patients were allocated into two treatment groups: BT injected into MR or conservative treatment. Inclusion criteria were attendance of two visits with basic orthoptic assessment. Exclusion criteria were: presence of further oculomotor palsies, strabismus, strabismus surgery and suppression. Non-parametric statistical analysis was conducted using IBM® SPSS Statistics.

Results

606 patients were identified. 137 patients met the inclusion criteria. 45.26% were treated with BT injections and 54.75% were treated conservatively. The median initial abduction deficit was greater in the BT group, -4 to -5 (after Scott & Kraft) than in the conservative treatment group, -1. As a result, the initial angle of deviation at distance was significantly larger in the BT group than in the conservative group. The recovery rate in the BT group was 24.19% and 20% in the conservative treatment group. The improvement of the angle of deviation at distance in all patients was greater in the BT group. The improvement of motility in bilateral palsies were greater in the BT group, but in unilateral palsies, there was no significant difference in motility improvement in the groups.

Conclusion

BT injections could not improve recovery rates. But BT injections could improve the angle of deviation greater. Additionally, BT was able to improve the motility in bilateral palsies greater than conservative treatment. An injection should be discussed in bilateral paralysis to enable fixation, patients with high levels of suffering and marked abnormal head posture. Patients should be informed about the high risk of adverse events, but also their transient nature.