Interpectoral-pectoserratus plane (PECS II) block in patients undergoing trans-axillary thoracic outlet decompression surgery; A prospective double-blind, randomized, placebo-controlled clinical trial

STUDY OBJECTIVE: To investigate if an interpectoral-pectoserratus plane (PECS II) block decreases postoperative pain, postoperative nausea and vomiting and improves quality of recovery in patients with neurogenic thoracic outlet syndrome (NTOS) undergoing trans-axillary thoracic outlet decompression surgery.

DESIGN: A prospective single center double blinded randomized placebo-controlled trial.

SETTING: Perioperative period; operating room, post anesthesia care unit (PACU) and hospital ward.

PATIENTS: Seventy patients with NTOS, undergoing trans-axillary thoracic outlet decompression surgery.

INTERVENTIONS: Patients were randomized to an interventional arm, receiving the block with 40 ml ropivacaine 0.5% (concentration was adjusted if the patient's weight was <66 kg), and a placebo group, receiving a sham block with 40 ml NaCl 0.9%. The interpectoral-pectoserratus plane block was performed ultrasound guided; the first injection below the pectoral minor muscle and the second below the pectoral major muscle. The hospitals' pharmacist prepared the study medication and was the only person able to see the randomization result. The study was blinded for patients, researchers and medical personnel.

MEASUREMENTS: Primary outcome parameters were postoperative pain, measured by numeric rating scale on the 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 h. Secondary outcome parameters were postoperative nausea and vomiting, and quality of recovery.

MAIN RESULTS: There was no statistically significant difference in NRS on the PACU at the start (ropivacaine 4.9 ± 3.2 vs placebo 6.2 ± 3.0, p = .07), at the end (ropivacaine 4.0 ± 1.7 vs placebo 3.9 ± 1.7, p = .77), on the ward on POD 0 (ropivacaine 4.6 ± 2.0 vs placebo 4.6 ± 2.0, p = 1.00) or POD 1 (ropivacaine 3.9 ± 1.8 vs placebo 3.6 ± 2.0, p = .53). There was no difference in postoperative morphine consumption at the PACU (ropivacaine 11.0 mg ± 6.5 vs placebo 10.8 mg ± 4.8, p = .91) or on the ward (ropivacaine 11.6 mg ± 8.5 vs placebo 9.6 mg ± 9.4, p = .39).

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