Effect of scalp block on postoperative pain relief in craniotomy patients

The efficacy of scalp nerve block using 0.5% bupivacaine with adrenaline for postoperative pain relief in craniotomy patients was evaluated in 40 ASA I or II adult patients undergoing supratentorial craniotomy. A standard general anaesthesia technique was followed. Patients were randomly divided into two groups. Group B received 0.5% bupivacaine with 1:400,000 adrenaline and group S received normal saline with 1:400,000 adrenaline, both after skin closure. Postoperative pain was assessed at 30 seconds and 1, 2, 4, 6, 8 and 12 hours using a numerical rating scale. Diclofenac IM was administered as rescue analgesia if patients reported a numerical rating scale of 40 or more. Tramadol IV was administered as second rescue analgesia. Sixty per cent of patients in group S experienced moderate to severe pain (numerical rating scale of 40 or more) at some time during the first 12 postoperative hours in comparison to 25% patients in group B. Median pain scores were significantly lower in group B for up to 6 hours. Significantly more patients were pain free up to four hours in group B. Median duration for the requirement of first dose of diclofenac was longer in group B compared to group S (360 min vs 30 min, P < 0.01). The number of doses of diclofenac (5 vs 19) was significantly lower in group B compared to group S (P < 0.01). Tramadol was required by six patients in group S only. Scalp nerve block using 0.5% bupivacaine with 1:400,000 adrenaline decreases the incidence and severity of postoperative pain in patients undergoing supratentorial craniotomy.