Effectiveness and Safety of Single Percutaneous Peribulbar Block Using Magnesium Sulphate as an Adjuvant to Local Anesthetics Versus the Standard Peribulbar Block for Strabismus Surgery in Adults

Peribulbar anesthesia in ophthalmic surgeries is limited by delayed and/or incomplete orbital akinesia and inadequate operative and postoperative analgesia. The aim of this study was to assess the safety and effectiveness of a single percutaneous peribulbar block technique with 100 mg magnesium sulphate added to the local anesthetics used compared with the standard peribulbar block technique in adult strabismus surgery. A total of 54 consecutive patients undergoing strabismus surgery were included in the study. They were divided into two equal groups (27 patients each). In group I, 1 ml (100 mg/ml) magnesium sulphate added to a mixture of 2 ml lidocaine 2%, 2 ml bupivacaine 0.5% and 1 ml hyaluronidase (150 units/ml) was administered through a single percutaneous peribulbar injection with a short (1 inch) needle, while in group II, a mixture of 1 ml saline added to 2 ml lidocaine 2%, 2 ml bupivacaine 0.5% and 1 ml hyaluronidase (150 units/ml) was administered using the standard peribulbar block technique. The collected data included patient's baseline characteristics, perioperative and early postoperative outcomes and follow-up data. The elapsed time before the onset of anesthesia and akinesia of the globe was significantly shorter in group I compared with group II (1.9 ± 0.7 vs. 3.9 ± 1.0 min, p < 0.001; 2.3 ± 0.7 vs. 4.4 ± 1.2 min, p < 0.001 respectively), and the duration of anesthesia was significantly longer in group I compared with group II (180.0 ± 0.0 vs. 43.0 ± 8.5 min, p < 0.001). The median VAS pain score was significantly lower in group I compared with group II (1.0 vs. 4.0, p < 0.001), and the patient's satisfaction was significantly higher in group I compared with group II (100.0% vs. 25.9%, p < 0.001). Co-administration of 100 mg magnesium sulphate with the local anesthetics was effective and safe. It achieved suitable conditions to start surgery rapidly. Further, it improved the quality of operative conditions and patient satisfaction.