Novel Retrobulbar Anesthesia Technique Through the Sub-Tenon's Space Using a Sharp Needle in a Blunt Cannula

BACKGROUND AND OBJECTIVE: The authors developed a new technique for retrobulbar anesthesia and compared it with the conventional transcutaneous method in 223 eyes undergoing vitrectomy. PATIENTS AND METHODS: In the new technique, a 24-mm-long 19-gauge curved cannula with a 27-gauge straight needle with an oval tip was inserted into the sub-Tenon's space, and then the oval-tipped needle was replaced with a 50-mm-long 25-gauge curved needle. Anesthetic was then injected into the muscle cone from the syringe. The authors compared 118 eyes undergoing vitrectomy with the new technique and 105 eyes undergoing the procedure with conventional anesthesia. RESULTS: The pain scores were 0.1 +/- 0.32 for the new technique and 1.57 +/- 0.73 for the conventional technique (P < .001). Additional anesthetic required was 0.1 +/- 0.33 mL using the new technique and 0.3 +/- 0.68 mL using the conventional method (P = .03). CONCLUSION: This novel approach to retrobulbar anesthesia using a guarded cannula is safe and effective, causing less pain than the conventional technique.