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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.