Evaluation of Clinical Efficacy of Scalp Block with 0.25% Injection Bupivacaine and 0.25% Injection Levobupivacaine to Blunt the Hemodynamic Response to Skull Pin Insertion during Supratentorial Craniotomies - A Prospective Study

BACKGROUND Head fixation is necessary to maintain the desired head position. Application of skull pins in neurosurgery leads to hemodynamic changes and this sudden change can be prevented by combining general anaesthesia with scalp block which blocks supraorbital nerve, supratrochlear nerve, zygomaticotemporal nerve, auriculotemporal nerve, lesser occipital nerve and greater occipital nerve which are present in superficial and deep layers of the scalp. Several studies have been done to study the efficacy of  Injection levobupivacaine and injection bupivacaine in 0.5 % concentrations for scalp block. However, the comparative efficacy of 0.25% injection levobupivacaine and injection bupivacaine for scalp block has not been determined by any study previously. We wanted to compare the efficacy of 0.25% injection levobupivacaine and 0.25% injection bupivacaine in scalp block on the haemodynamic response to head pinning, incision and during craniotomy. METHODS This prospective randomised study included 60 patients of ASA status I or II between age 18–60 years and of either sex who underwent supratentorial craniotomy under general anaesthesia followed by scalp block. Patients were randomly allocated into two groups of 30 each and before application of the Mayfield skull pin head holder, scalp block was given as per group distribution (Group A: 20 ml 0.25% injection bupivacaine and Group B: 20 ml of 0.25% injection levobupivacaine). The hemodynamic responses were recorded at baseline, during scalp block and after head pin insertion, incision and at craniotomy. The total analgesic requirement during intraoperative and post operative period was noted. RESULTS There were no clinically and statistically significant differences in values of heart rate and blood pressure after head pin insertion, skin incision and craniotomy in both the groups. CONCLUSIONS The study revealed that 0.25% injection levobupivacaine when used for scalp block was as efficacious as 0.25% injection bupivacaine. Both the drugs in low concentration of 0.25% were effective in minimizing pressor response to skull pin insertion, incision and craniotomy with less incidence of complication and reduced intraoperative requirement of analgesia.