Preoperative Sub-Tenon Block Decreases Perioperative Pain Severity and Adverse Complications

This study was designed to evaluate the efficacy of sub-tenon block (preemptive analgesia) after general anesthesia and before beginning the repair of retinal detachment (RD) surgery by using scleral buckle and cryopexy.
Sixty eight patients scheduled for RD surgical repair with "American Society of Anesthesiologists" (ASA) I or II were included in this clinical trial study. The patients were randomly and blindly divided into two equal groups. The surgery was done under general anesthesia in both groups, but in the case group, sub-tenon block was given as preemptive analgesia after the induction of general anesthesia with similar methods and before the start of surgery.
The incidences of intra and postoperative (up to 24 hours) oculocardiac reflex (OCR), ischemic heart disease (IHD) changes, nausea and vomiting (PONV), delirium, total analgesic drug consumption and ocular severity of pain were significantly lower in the case group compared with the control group (p<0.05). Mean blood pressure, heart rate,
time of discharge from the hospital, frequency of requirement to analgesic drug, intra and postoperatively were significantly lower in the case group compared with the control group (p<0.05).
According to this research, the use of sub-tenon block in RD surgery effectively reduces PONV, postoperative pain, analgesic drug requirements, delirium, discharge time from the hospital, IHD, hemodynamic changes and OCR, therefore it is recommended for daily routine ophthalmologic surgeries.