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

Abstract

Background 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. Methods Retrospective 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. Results The 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%). Conclusions The 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.

Inferior Oblique Anterior Transposition versus Myectomy for Inferior Oblique Overaction: Systematic Review and Meta Analysis

“…Table 1 summarises the baseline characteristics of the included studies. [12][13][14][15][16][17][18][19][20][21][22] The majority of the studies were retrospective with a total sample of 728 subjects. The studies were homogenous in the population and design comparing anterior transposition versus myectomy for the treatment of IOOA.…”

“…4,9 On the other hand, myectomy tends to have a simpler technique and a shorter operation time; however, it is associated with a risk of residual or recurrent IOOA. 9 Although several studies have compared the effectiveness of anterior transposition and myectomy for correcting IOOA, [12][13][14][15][16][17][18][19][20][21][22] there are currently no meta-analyses comparing the outcomes of the two interventions to reach a consensus. This is therefore the first study in the literature amalgamating the data of these studies.…”

Novel Inferior Oblique Muscle Y Splitting Procedure to Minimize the Anti-Elevation Syndrome: A Pilot Study

“…Nevertheless, these procedures are also intended to correct the primary gaze hypertropia as well as excyclotorsion. [1][2][3][4][5][6][7] In clinics, the inferior oblique muscle overaction is frequently encountered in infantile esotropes, where it can be witnessed in up to 70% of the cases, 1 such overactions can also be witnessed in superior oblique palsy, comitant horizontal deviations, dissociated vertical deviation, and others. To treat it, in milder grades (usually 1+), we prefer 8-10 millimeters of inferior oblique recession, and in grade 2+ we prefer 12-14 millimeters of recessions or Elliott and Nankins procedure.…”

“…In grades 3+ and 4+, we prefer the anteriorization procedure or the antero-nasal transposition procedure, where the primary gaze hypertropia as well as the excyclotorsion are taken care of. Apart from these, myectomy and many other procedures have been described in literature, 3,4,[6][7][8] however we rarely prefer them.…”

Differences in gene expression between the primary and secondary inferior oblique overaction

“…In congenital esotropia, the fusion faculty is considered absent, and binocularity does not exist in these patients (3,6). However, in SOP, patients adopt a compensated head posture to help eliminate diplopia and obtain a normal retinal correspondence and good binocularity (4,7,8). The 4 cyclovertical muscles in our eyes (which comprise 2 superior and 2 inferior oblique muscles) are mainly involved in the vertical fusion of SOP, and patients with congenital SOP usually have a larger than normal vertical fusion amplitude.…”