Background
Most ophthalmic procedures are performed under local anesthesia, and cataract extraction is the most frequently performed surgery in elderly patients. The aim of this study is to compare the intraoperative hemodynamic variables, efficacy, and efficiency of extraconal block versus subtenon block with low concentration of local anesthetic during cataract surgery.
Patients and methods
This prospective, randomized, and single-blind study was done on 80 patients American Society of anesthesiologists status I–III undergoing cataract surgery, of which 40 patients underwent subtenon block (group S) and 40 patients underwent extraconal block (group E). Five minutes after the start of anesthetic monitoring care, 5-ml mixture of lidocaine 1% and bupivacaine 0.25% containing 100 IU hyalorunidase, in a mixture ratio of 1 : 1, was injected intraocular slowly. Patients were monitored for intraoperative hemodynamics, ocular movement during surgery, and intraoperative pain sensation as primary outcome, and onset of blockade, pain assessment within 30 min postoperatively, number of patients need rescue dose, surgeon discomfort, and postoperative complications as secondary outcomes.
Results
Mean arterial blood pressure and heart rate in group S were significantly lower than those in group E but within safety margin. No significant difference was found between the two groups regarding full range of eye movement, surgeon's discomfort grade during cataract surgery, and also, intraoperative pain sensation. The onset of blockade was significantly faster in group S than group E. Although group S had better postoperative analgesic effect than group E, postoperative rescue dose was of insignificant value.
Conclusion
Subtenon block seems to be a better local anesthetic technique than extraconal for cataract surgery, as it is faster, has less surgeon discomfort grading, and better postoperative analgesia. However, on the contrary, both subtenon and extraconal blocks are equally effective in pain control during surgery and also have good ocular akinesia during operation.