Formulation of a Peribulbar Block for Prolonged Postoperative Pain Management in Vitreoretinal Surgery: A Randomized Clinical Trial.

PURPOSE: To evaluate postoperative pain level using a supplemental peribulbar injection at the conclusion of retinal surgery. DESIGN: Prospective, parallel-assigned, single-masked, randomized clinical trial. PARTICIPANTS: Fifty-eight patients undergoing scleral buckle, vitrectomy, or combined surgery. METHODS: In a single academic institutional practice, 58 patients undergoing scleral buckle, vitrectomy, or combined surgery were enrolled. Exclusion criteria included those with a risk for glaucoma, a pre-existing chronic pain disorder, among others. Patients were assigned randomly to receive a postoperative peribulbar formulation of either bupivacaine, triamcinolone acetonide, and cefazolin (group A) or bupivacaine, balanced salt solution, and cefazolin (group B). The postoperative pain score and ocular motility were assessed by a masked observer on the first postoperative day. MAIN OUTCOME MEASURES: The primary outcome measure was the postoperative pain score. Secondary outcome measures included oral analgesic use, ocular motility, and intraocular pressure (IOP). RESULTS: The mean pain scores were 2.8±2.9 for group A and 3.8±2.6 for group B (P = 0.095). Pain was absent in 28% of group A patients versus 14% of group B patients (P = 0.11). Group A required less narcotic pain medication (hydroxycodone: group A, 0.7±3 mg vs. group B, 3±6 mg; P = 0.05; oxycodone: group A, 7±7 mg vs. 9±13 mg; P = 0.2) than group B. Motility was full in group B and limited in group A (P ≤ 0.001), with no differences in mean IOP measurements at any point after surgery. CONCLUSIONS: We did not demonstrate a statistically significant reduction in mean postoperative pain scores. However, patients in group A required less hydroxycodone use and had greater akinesia, suggesting prolonged neural blockade.