Postoperative pain after thoracic outlet decompression surgery might be improved by adding a regional anesthesia technique to the analgesia regimen. The aim of this study was to investigate if an interpectoral-pectoserratus plane (Pecs II) block decreases postoperative pain, postoperative nausea and vomiting and improved quality of recovery.

We performed a prospective double-blinded randomized [1:1] placebo-controlled parallel-group study. Patients with neurogenic thoracic outlet syndrome planned for trans-axillary thoracic outlet decompression surgery were randomized to an interventional arm, receiving a block with ropivacaine 0.5%, and a placebo group, receiving NaCl 0.9%. The hospitals' pharmacist prepared the study medication, blinded for patients, researchers and medical personnel. Primary outcome parameters were postoperative pain, measured by numeric rating scale on the post anesthesia care unit (PACU) (start and end) and on the ward on postoperative day (POD) 0 and 1, and postoperative morphine consumption, measured on the PACU and on the ward during the first 24 hours.

Seventy patients received an interpectoral-pectoserratus plane block with ropivacaine (n=35) or placebo (n=35). There was no difference in NRS on the PACU at the start (ropivacaine 6.2 ± 3.0 vs placebo 4.9 ± 3.2, p=.08), or the end (ropivacaine 3.9 ± 1.7 vs placebo 4.1 ± 1.6, p=.77), and on the ward on POD 0 (ropivacaine 4.6 ± 2.0 vs placebo 4.6 ± 2.0, p=.10) and POD 1 (ropivacaine 3.6 ± 2.0 vs placebo 3.9 ± 1.8, p=.53). There was no difference in postoperative morphine consumption at the PACU (ropivacaine 8.9 mg ± 6.0 vs placebo 9.7 mg ± 7.1, p=.62) and on the ward (ropivacaine 9.6 mg ± 9.4 vs placebo 11.6 mg ± 8.5, p=.39). There was no difference in postoperative nausea and vomiting at the PACU, on POD 0 and 1.

The interpectoral-pectoserratus plane block is not effective for postoperative analgesia in patients undergoing trans-axillary thoracic outlet decompression surgery.