Retrobulbar anaesthesia for adjustable strabismus surgery in adults: a prospective observational study.

OBJECTIVE: To characterize the ocular response to retrobulbar anaesthesia and to evaluate the efficacy of retrobulbar anaesthesia for adjustable strabismus surgery in adults.

DESIGN: Prospective observational study.

PARTICIPANTS: Adult patients undergoing adjustable strabismus surgery under retrobulbar anaesthesia.

METHODS: Surgical success was defined by ocular alignment within 10 prism diopters (PD) of orthotropia for horizontal rectus surgery and within 5 PD for vertical rectus surgery. After retrobulbar injection of Xylocaine with epinephrine, the onset time and the degree of visual impairment, ocular akinesia, and analgesia were evaluated. Postoperative parameters included the restoration of vision, onset of pain, resolution of ptosis, normalization of pupil, resolution of extraocular motility deficits, and the timing of postoperative adjustment. Perioperative complications were also documented.

RESULTS: A total of 33 patients were initially included in this study. Two patients experienced complications (perioperative retrobulbar hemorrhage, postoperative suprachoroidal hemorrhage) and were excluded from data analysis. Of the remaining 31 patients (mean age, 50.2 ± 14.8 years), surgical outcome was satisfactory in 30/31 (96.8%) patients at the first postoperative visit and in 15/19 (78.9%) cases at last follow-up (mean, 6.1 ± 1.6 months). Excellent intraoperative ocular akinesia and analgesia was achieved with retrobulbar anaesthesia. After retrobulbar injection, visual impairment was the first to resolve to preoperative levels within (mean ± SD) 3.7 ± 1.9 hours postinjection, followed by onset of pain at 4.1 ± 1.0 hours, resolution of ptosis at 4.3 ± 1.9 hours, and normalization of pupil reactivity at 6.1 ± 1.0 hours. The resolution of anaesthesia upon extraocular motility occurred within 5.7 ± 1.0 hours postinjection (range, 4.5-8.0 hours), allowing for subsequent same-day postoperative adjustment.

CONCLUSIONS: Retrobulbar anaesthesia in the context of adult, adjustable strabismus surgery is a relatively safe and effective technique. It provides excellent intraoperative analgesia and akinesia. Retrobulbar anaesthesia enables for same-day suture adjustments to be reliably performed.