Superficial extraconal blockade for vitreoretinal surgery

CONTEXT: Needle length plays an important role for the success of ophthalmic block. The standard practice is to use 25 mm needles length; however, unnecessarily long needles may increase the risk of complications especially in the presence of staphyloma or previous scleral buckle. AIMS: This work was designed to compare the efficacy of using 15 and 25 mm needle in performing extraconal block for patients undergoing vitreoretinal surgery. SETTINGS AND DESIGN: Prospective randomized double blinded study. MATERIALS AND METHODS: A total of 120 patients were enrolled in this study and were divided in two groups. In group (1) extraconal block was performed using 25 mm needle, while in group (2) 15 mm needle was used. After primary injection, assessment of the block was done by an anesthesiologist who was unaware of the needle used. If satisfactory akinesia was not achieved a supplementation was provided. At the end of the procedures, patients and surgeons were asked to assess their pain and satisfaction with the anesthetic technique. STATISTICAL ANALYSIS USED: The sample size calculation using N-Quary version 4. Numerical and categorical data were analyzed using an independent sample, a two-tailed t-test, and chi-square test, respectively. RESULTS: The volume of primary injectable was significantly higher in group 2. The two groups were comparable as regards total volume of local anesthetic, supplementation rate, akinesia, pain score, and surgeon satisfaction. CONCLUSIONS: Using 15 mm needle length to perform extraconal blockade for posterior segment procedures is equally effective to 25 mm needle.