Bupivacaine Injection to Lateral Rectus in Abducens Nerve Palsy
A 49-year-old female presented with esodeviation, which occurred one year after a traffic accident. Snellen visual acuity was 20 / 20 in both eyes. Bilateral abducens nerve palsies were diagnosed on neurological examination. The primary position deviation was 75 prism diopter (PD) esotropia on the alternate cover test (). The extraocular movement of the LR was -1 limitation for the right eye and -4 limitations for the left. No evidence of neurological impairment was present, and magnetic resonance imaging (MRI) of the brain was normal. After performing orbital MRI and discussing its experimental nature with the subject, informed consent was obtained for a BUP injection. A flaccid LR of the left eye was confirmed by exposing the muscle through a swan incision 8 mm from the limbus. Using a 30-gauge needle, 2 mL of BUP (5 mg/mL) was injected into the LR. One month after injection, there was no change in deviation, and a further orbital MRI was performed (). Subsequently, the recession of both medial rectus (6 mm) and resection of the left LR (9 mm) led to orthotropia until 18 months (). At the left LR resection, traction testing demonstrated restriction of the medial gaze compared to before BUP injection. The formerly-injected LR was 'stiff' on surgical observation.