Comparison of Needle Path, Anesthetic Dispersion, and Quality of Anesthesia in Retrobulbar and Peribulbar Blocks.

Abstract

To compare the needle path during retrobulbar ophthalmic block with that during peribulbar ophthalmic block, its relation with anesthetic spread, and the quality of the anesthesia. This is a prospective comparative study in selected candidates of ophthalmic blocks for phacoemulsification. The procedure used a 22-gauge 1 needle in a single lateral inferior transcutaneous puncture with 5 mL of anesthetic solution with radiological contrast. Patients were randomly divided into 2 groups: GI, retrobulbar block; GII, peribulbar block. Computed tomography scans of the orbit were performed at the time of the blockade and 10 minutes after anesthetic injection. The quality of anesthesia was assessed by measurement of ocular motility at 3, 5, and 10 minutes after the block. Twenty eyes per group were included. The needle path was intraconal in 10 cases in GI and in no patient in GII, transfixed the muscle cone in 5 cases in GI and in 4 in GII, and was extraconal in 2 cases in GI and in 13 in GII. The anesthetic dispersion was directly related to the needle path. In all extraconal cases, the block was unsatisfactory. It was satisfactory when the path of the needle was intraconal or the cone was transfixed (P = 1.0). The quality of anesthesia was higher in the retrobulbar block (P < 0.01). The path of the needle contributed to the orbital anesthetic solution dispersion and the quality of anesthesia. The retrobulbar block technique provided better-quality anesthesia compared with the peribulbar one.