Ultrasonography- or electrophysiology-guided suprascapular nerve block in arthroscopic acromioplasty: a prospective, double-blind, parallel-group, randomized controlled study of efficacy.

Purpose: To evaluate the efficacy of ultrasonography-guided (UG) and electrophysiology-guided (EG) suprascapular nerve block (SNB) for arthroscopic acromioplasty with regard to pain relief.

Methods: A prospective, double-blind, randomized controlled clinical trial was performed from June 2007 to April 2010. Patients who were scheduled for elective arthroscopic acromioplasty and who met the inclusion criteria were assigned to 1 of 2 experimental groups (UG or EG SNB) or to 1 blind group (using anatomic landmarks). Before surgery, an SNB was performed with either ultrasonographic or electrophysiologic guidance or with no assistive devices (blind). Variables were collected at 4, 24, 48, and 72 hours postoperatively.

Results: Sixty-three patients were initially enrolled in the study, but 11 dropped out for various reasons. In the UG group at 4 hours, the visual analog scale score at rest (30 ± 12.0 v 39 ± 9.9 for EG group and 41 ± 11.8 for blind group) and when the patient was moving (42 ± 15.2 v 52 ± 11.5 for EG group and 53 ± 12.6 for blind group) was significantly decreased compared with the EG and blind groups (P < .05). Opioid consumption during the first 24 hours was significantly reduced in the UG and EG groups (4.3 ± 1.9 mg and 3.8 ± 2.3 mg, respectively) compared with the blind group (5.1 ± 2.2 mg) (P < .05). The visual analog scale score at rest and when the patient was moving; the pain score on the University of California, Los Angeles questionnaire; and the activities of daily living score on the American Shoulder and Elbow Surgeons questionnaire in the EG and UG groups improved more than the values in the blind group over the follow-up intervals (P < .05). Morphine consumption in the EG and UG groups by the first, second, and third days was significantly smaller than that in the blind control group (P < .05).

Conclusions: UG and EG SNB can reduce pain and painkiller consumption for up to 72 hours postoperatively. Ultrasonographic or electrophysiologic guidance is more effective than the blind method of SNB.

Level Of Evidence: Level I, randomized controlled trial with significant difference.