Comparison of incidence of oculocardiac reflex between hang-back and conventional rectus recession in horizontal strabismus surgery

Abstract

To compare the incidence of oculocardiac reflex(OCR) between hang-back and conventional method of rectus muscle recession in horizontal strabismus.In this prospective, randomized, double blind study, 40 consecutive patients of horizontal strabismus were evaluated. The patients were randomized into two groups based on the type of surgical recession technique employed for squint correction. Twenty patients were operated by Hang-back technique (group-1) and 20 by conventional rectus muscle recession where the muscle tendon was sutured directly to the globe (group-2). All patients underwent pre-operative evaluation which included refraction, keratometry and assessment of angle of deviation etc. ECG was monitored before surgery. During surgery heart rate (HR) was recorded as heart rate baseline (HRB), after 5 minutes of intubation (HR5), during muscle traction (HRT), Minimum heart rate during traction of muscle (HRMin), Maximum increase in heart rate (HRMax). OCR was defined as > 20% reduction in HR during muscle traction as compared to baseline HR. Out of total 40 patients 17(42.50%) were having exotropia and 23 (57.50%) had esotropia. The overall incidence of OCR in conventional recession was found to be greater than that in hang-back recession. The mean baseline HR was 72.00± 7.391 beat/min in conventional recession group and 77.55± 7.494 beat/min in hang-back recession group. The mean HR reduction in conventional procedure was 56.05± 8.787 beat/min. and that in hang-back procedure 61.80 ± 9.317 beat/min., which was statistically significant (p<0.01). This was probably attributed to the shorter duration of surgery and lesser manipulation during surgery in hang-back as compared to conventional procedure. OCR is a common complication encountered during manipulation of muscle during strabismus surgery. Hang-back recession is a safe and effective method of muscle recession as it offers a shorter surgical time and better exposure along with lesser incidence of OCR with similar success rates when compared to conventional muscle recession.