Rocuronium versus magnesium as an adjuvant to local anesthetics in peribulbar block

Background Peribulbar eye block is a safe and inexpensive technique with the advantage of providing efficient anesthesia with good lid and globe akinesia. It is also an effective treatment foroperative pain. It has become common practice to use the polypharmacy approach to enhance the onset and increase the duration of the block, because no drug has yet been identified that specifically inhibits nociception without associated side effects. Methods This prospective double-blind randomized controlled study included 75 patients of either sex who were candidates for cataract surgery, between 40 and 80 years of age, with an American Society of Anesthesiologists physical status of I–III. Peribulbar block was performed in the operating room by a senior anesthesiologist who was unaware of the nature of the solution injected. The patients were divided randomly into three groups according to the medications they received: group O (control group): localanesthetic + 0.9% saline (1 ml); group M: local anesthetic + magnesium sulfate 50mg in 1ml of 0.9% saline; group R: local anesthetic + 0.06 mg/kg rocuronium (maximum 5 mg) in 1ml saline. The success of the block was evaluated by scoring the mobility of the globe and the eyelid, as well as by assessing corneal anesthesia. Results Time to start surgery was significantly lower in the rocuronium (R) group; however, complete corneal anesthesia was achieved in all groups at 10 min. No pain waspresent in any case, but a supplemental dose was required in groups O and M to achieve complete akinesia. Conclusion The addition of rocuronium to the local anesthetic mixture results in a better akinesia score and faster establishment of suitable conditions to start cataract surgery compared with those in the magnesium and placebo groups.