The effect of interscalene block on ipsilateral shoulder pain and pulmonary function in patients undergoing lung lobectomy: A randomized controlled trial

Background: Postoperative ipsilateral shoulder pain occurs in 37% to 68% of patients undergoing a thoracotomy. We examined whether interscalene brachial plexus block using a lower concentration of local anesthetic would reduce the incidence of postthoracotomy ipsilateral shoulder pain with assessment of pulmonary function in patients who underwent a lung lobectomy. Methods: Forty-four patients who underwent a lung lobectomy were randomly assigned to either the control or the interscalene block group. Single-shot interscalene block on the surgical site side was performed using ropivacaine 0.25% 10 mL including dexamethasone 5 mg under ultrasound guidance in the interscalene block group. Lobectomy and continuous paravertebral block were performed under general anesthesia. The presence of ipsilateral shoulder pain and postoperative adverse events were assessed. Pulmonary function tests were performed preoperatively, the day after surgery, and the day after removing the chest tube. Results: The incidence of ipsilateral shoulder pain was significantly lower in the interscalene block group than in the control group (54.5% vs 14.3%, P = .006) with an overall incidence of 34.9%. Postoperative adverse events were similar between the groups, with no patients presenting symptoms of respiratory difficulty. Significant reductions in pulmonary function were observed in all patients after lobectomy; however, no significant difference in any of the pulmonary function test variables was observed postoperatively between the groups. Conclusions: Interscalene block using 10 mL of 0.25% ropivacaine including dexamethasone 5 mg reduced the incidence of postthoracotomy ipsilateral shoulder pain and did not result in additional impairment of pulmonary function.