Ropivacaine 0.75% versus a mixture of lidocaine 2% and 0.5% bupivacaine for peribulbar anesthesia for anterior segment eye surgery

The purpose of this prospective, randomized, double-blinded study was to compare ropivacaine and a lidocaine bupivacaine mixture in peribulbar anesthesia. Eighty ASA [American Society of Anaethesiology] physical status group I or II patients scheduled for elective anterior segment surgery [cataract extraction with intraocular lens implantation] were randomized to receive a peribulbar block with of either 0.75% ropivacaine [ropivacaine group/ n = 40] or a 1:1 mixture of 2% plain lidocaine and 0.5% plain bupivacaine [lido-bupivacaine group, n = 40]. Pain during injection, time required for onset of surgical anesthesia, quality of postoperative analgesia, akinesia, hemodynamic effect, intraocular pressure and incidence of side effects, were recorded pain is more with lido-bupivacaine group than ropivacaine group. Surgical block was achieved after 8 min in both groups, with no statistical significant differences as regard duration of surgery, hemodynamic effects, perioperative complications and Pao[2] pain at the night of surgery is 50% [20 patients] for lidobupivacaine group and 10% [4 patients] for ropivacaine group. As regard diplopia at 24 hours no statistical differences were found but there is highly significant difference at 6 hours. We concluded that 0.75% ropivacaine may be a suitable choice when performing peribulbar anesthesia for anterior segment surgery. We demonstrated that ropivacaine has an onset similar to that of the lidocaine-bupivacaine mixture and provided a better quality of postoperative analgesia and less diplopia. Regional anaesthesia for intra-ocular surgery has become popular over the last few years. Pribulbar anaesthesia is recognised as a safe regional anaesthesia technique to carry out most ophthalmic surgical procedures[2]. In 1985 Davis and Mandel[1] reported 3 years experience with injection of local anaesthesia outside the cone into the posterior peribulbar space [periocular]. The advantages of peibulbar compared with the retrobulbar technique appear to include a reduced incidence of serious complication such as brain stem anaesthesia, intravascular injection, scleral perforation and retrobulbar haemorrhage. Various additives to the local anaesthetic have been used in an atempt to improve the quality of anaesthesia and operating conditions; mixtures of rapid onset and longer acting local anaesthetics, adrenaline, hyaluronidase and alkalinisation[10]. One disadvantage with peribulbar when compared with retrobulbar blockade is delayed or incomplete akinesia of the eye[12]. Mixture of bupivacain and lidocain is used to obtain a fast onset of both sensory and motor blockade and to prolong postoperative analgesia[8]. Ropivacaine, is a new long-acting amide local anesthetic agent with fewer toxic cardiac and central nervous system effects [provides greater separation of sensory and motor effects. These properties suggest advantages when compared with other for regional anesthesia and post operative analgesia[6]. Several studies have demonstrated the efficacy of ropavacain in different regonal anesthesia techniques