Sub-tenon's block; effect of addition of fentanyl to local anesthetic for quality of block and postoperative analgesia

ABSTRACT

The "perfect" regional anesthetic technique involves "painless application, hundred percent anesthesia, hundred percent akinesia, and risk free". The quality of perioperative analgesia and intraoperative akinesia are the main aims of ophthalmic regional anesthesia. Sub-Tenon's local anesthesia becomes an accepted technique for posterior segment eye surgery. It is a safe, quick, and effective method of local anesthesia. However, it requires a certain amount of skill for dissection into the sub-Tenon's space. Fentanyl is powerful opioid analgesic drug used in neuraxial and peripheral nerve blocks, this study aimed at evaluating whether fentanyl has contributed to blockade quality and postoperative analgesia in sub-Tenon's local anesthesia. This study included fifty eyes of patients in a randomized, prospective clinical study undergoing vitreoretinal surgery under sub-Tenon's local anesthesia. After departmental approval and informed consent was obtained from all patients, fifty patients of both gender, 20-75 years old, ASA physical status I-III, participated in this study, the patients were distributed into two groups [1] Control group 6 ml a mixture of lidocaine 2%, bupivacaine 0.5% in equal proportion, and hyaluronidase 25 IU.ml[-1]; [2] Fentanyl group 6 ml of the same mixture associated with 25 micro g fentanyl. Blockade quality was evaluated according to the following parameters intraoperative pain, eyelid and/or eyeball movement, quality of akinesia, postoperative analgesia and patient satisfaction of blockade, Results showed that fentanyl has significantly improved blockade quality of analgesia intraoperatively [with fentanyl 100%; without fentanyl 74% p value 0.008] and has highly significant efficient postoperative analgesics at 1, 2, 4, 6, and 24 hrs postoperatively [with fentanyl 72%; without fentanyl 16% P value 0.001]. Concomitant use of fentanyl with local anesthetics in Sub-Tenon's block is a safe and effective method to improve quality, reduce intraoperative local anesthetics and analgesics, and finally enhance postoperative analgesia in patients undergoing vitreoretinal surgery