Peribulbar anaesthesia using a combination of lidocaine, bupivocaine and clonidine in vitreoretinal surgery.

PURPOSE

The efficacy and safety of peribulbar anaesthesia was assessed using a combination of lidocaine, bupivacaine and clonidine during eye surgery.

METHODS

We prospectively studied 100 vitreo-retinal surgical procedures performed by several surgeons. The exclusion criteria included age below 30 years and, axial length of the orbit above 28 mm. Peribulbar was performed using Hamilton's technique. A mixed anaesthetic solution of equal quantity of lidocaine 2% and bupivacaine 0.5% with clonidine (1 mg/kg) was injected. Patients received a mean volume of 14.5 ml +/- 3.5 of the mixture. Akinesia and analgesia were assessed 15 minutes later by the surgeon. Whenever required, supplemental lidocaine 2% (3 ml) by sub-Tenon infiltration was added by the surgeon. Supplemental injections were given only to patients who failed to develop analgesia.

RESULTS

The mean age of patients (male 52%, female 48%) was 66 years +/- 10 (mean +/- SD, range 44-90). The 100 surgical procedures were made up of vitrectomy +/- gas +/- silicone oil (22/100), vitrectomy and lensectomy (6/100), vitrectomy and epiretinal membrane +/- laser coagulation +/- gas +/- silicone oil (35/100), scleral buckling or encircling +/- gas (36/100), and cryosurgery +/- gas (1/100). Analgesia was adequate throughout surgery without any supplementation in 85% of cases and with a sub-Tenon infiltration in 99%. Akinesia was complete in 84%, mild in 12% and absent in 4% of cases. The sub-Tenon injection was performed in 15% of cases. Three patients (3%) were agitated during surgery. No neurologic or cardiac complication was seen. In one patient, the systolic blood pressure decreased from 170 to 110 mmHg, 30 minutes after the institution of the peribulbar block.

CONCLUSION

Our results show that peribulbar anaesthesia in the proposed mixture offers excellent analgesia in 85% of patients, and in 99% of the patients when supplemented by a subtenon injection. The current mixture of lidocaine, bupivacaine and clonidine is an excellent alternative to the previously used mixture etidocaine, bupivacaine and hyaluronidase for vitreoretinal surgery. However, a randomized controlled clinical trial is needed to prove the efficacy and safety of these results.