Results of anterior tucking of the superior oblique muscle tendon in bilateral fourth nerve palsy.

BACKGROUND: Bilateral fourth nerve palsy is characterised by excyclotorsion, which can be corrected by reinforcement of the anterior tendon fibres of the superior oblique muscle. PATIENTS AND METHODS: A retrospective study of 40 consecutive patients with bilateral acquired fourth nerve palsy operated by a selective tuck of the anterior portion of the superior oblique tendon between 1994 and 2012 was undertaken. Horizontal, vertical and torsional deviations were measured in 9 diagnostic positions of gaze and the field of binocular single vision was evaluated with the Harms tangent screen. Postoperative follow-ups took place at 1 week, 6 months, and ≥3 years. RESULTS: Preoperative mean excyclotorsion was 9° in the primary position and 15° in downgaze. These values decreased to 2° and 5° 6 months after surgery, and 2.5° and 6° at ≥3 years. Immediate post-operative incyclotorsion in upgaze (28 patients) and Brown syndrome (15 patients) regressed spontaneously. The median score of field of binocular single vision improved from 4% preoperatively to 76% postoperatively. CONCLUSIONS: The selective tuck of the anterior tendon fibers of the superior oblique tendon enables an efficient and long-lasting correction of the ocular torsion induced by bilateral trochlear palsy.

Torsional strabismus and vertical rectus muscle surgery in thyroid eye disease.

PURPOSE: To assess the torsional component in patients with vertical strabismus due to thyroid eye disease (TED) and its course after vertical rectus muscle surgery. PATIENTS AND METHODS: Retrospective chart review of patients undergoing vertical strabismus surgery for TED between 1998 and 2017, having undergone pre- and postoperative Harms tangent screen examination. RESULTS: Forty patients (27 women) were identified. A torsional component was present in all patients. Thirty-three patients had a mean excyclotorsion of 4.5° in primary position, increasing to 8.2° in upgaze, associated with restricted elevation. Inferior rectus muscle recession (n=29) reduced the excyclotorsion in all cases. A 4.4° mean incyclotorsion was present in primary position in 7 cases, increasing to 7.1° in downgaze. Superior rectus muscle recession reduced the incyclotorsion in 5/6 cases. The torsional surgical dose-effect relationship was correlated with the amount of preoperative torsion. The field of binocular single vision improved from 6.5% preoperatively to 71.1% after surgery. CONCLUSIONS: Ocular torsion is common in vertical strabismus secondary to TED and is significantly improved by vertical rectus muscle surgery alone. Surgery should be planned according to vertical deviation and motility limitation, and vertical rectus muscles surgery should be considered the first line of treatment, with selective oblique muscle surgery as a second-line option, which was unnecessary in our series.