Surgical outcomes of three different weakening procedures of inferior oblique muscle in the treatment of unilateral superior oblique palsy

Mohamed F Farid,Mohamed Anany,Marwa Abdelshafy

doi:10.1186/s12886-020-01568-w

Mohamed F Farid, Mohamed Anany + Show 1 more

Open Access

https://doi.org/10.1186/s12886-020-01568-w

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Journal: BMC ophthalmology	Publication Date: Jul 20, 2020
Citations: 8	License type: open-access

Affiliation: Benha University

Abstract

BackgroundTo compare surgical outcomes and complications of three inferior oblique weakening procedures; Inferior Oblique Myectomy (IOM), Inferior Oblique combined Resection-Anterior Transposition (IORAT) and Inferior Oblique Anterior Transposition (IOAT) in the management of unilateral Superior Oblique (SO) palsy.MethodsRetrospective review of medical records of all patients with unilateral SO palsy who underwent one of the aforementioned IO weakening procedures at Benha University hospital was performed. Patients were excluded if surgery was bilateral or combined with other vertical muscle surgery. Primary outcome parameters were improvement of Hypertropia (HT) in primary gaze, side gazes, on alternate head turn, Inferior Oblique Overaction (IOOA), Superior Oblique Underaction (SOUA), correction of head tilt and postoperative complications.ResultsThe review reveals a total of 65 patients with unilateral SO palsy; 54 congenital and 11 acquired, who met the study criteria and were classified into 3 groups; IOM group (24cases), IORAT group (19cases) and IOAT group (22cases). Compared with IOM, both IORAT and IOAT induced significant correction of HT in primary position, ipsilateral gaze, contralateral head tilt and IOOA. IORAT was significantly more effective than IOAT in correction of HT in ipsilateral gaze and contralateral head tilt while there was no statistical difference between the three groups in correction of HT in ipsilateral gaze, contralateral head tilt and SOUA. Postoperative Anti-elevation was significantly recorded following IORAT (6 cases, 31%) than IOAT (3 cases, 13%) and IOM (one cases, 4%).ConclusionsThe IORAT and IOAT were more superior to IOM in correction of IOOA and HT in the primary position and some other gaze positions. However, superiority of IORAT over the other two procedures should be weighed against its significant association with postoperative underaction of IO muscle and anti-elevation syndrome.

Highlights

To compare surgical outcomes and complications of three inferior oblique weakening procedures; Inferior Oblique Myectomy (IOM), Inferior Oblique combined Resection-Anterior Transposition (IORAT) and Inferior Oblique Anterior Transposition (IOAT) in the management of unilateral Superior Oblique (SO) palsy
Preoperative HT in the primary position and contralateral gaze was considerably larger in IORAT and IOAT groups relative to IOM group, there was no statistically significant difference between different study parameters before surgery in all groups
Weakening of overacting IO muscle has been widely considered as the first surgical option in treatment of symptomatic SO palsy, and this is because its effectiveness in alleviation of ocular deviation and abnormal head positions while avoiding adverse side effects associated with other forms of strabismus surgeries such as iatrogenic Brown syndrome and overcorrections [1, 11].In previous reports concerning IOM, the average correction of HT in primary position ranged from 12.5 to 14 PD

Summary

Introduction

To compare surgical outcomes and complications of three inferior oblique weakening procedures; Inferior Oblique Myectomy (IOM), Inferior Oblique combined Resection-Anterior Transposition (IORAT) and Inferior Oblique Anterior Transposition (IOAT) in the management of unilateral Superior Oblique (SO) palsy. Diagnosis is often made by Parks-Bielchowksy three-step test, in which hypertropia (HT) increases on adduction of the involved eye and on ipsilateral head tilt. Wide varieties of surgical strategies have been proposed to treat unilateral SO palsy and they include strengthening of ipsilateral weak SO muscle (by tucking or advancement), weakening of ipsilateral overacting inferior oblique (IO) muscle, recession of the contralateral inferior rectus muscle or ipsilateral superior rectus muscle [4]. Weakening of the ipsilateral overacting IO muscle is currently the most common surgical procedure performed. Elliott and Nankin in 1982 [6] suggested that anterior transposition of IO muscle would increase its depressor effect, though this could be penalized by development of defective ocular elevation (anti elevation syndrome)

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