A commentary on “Efficacy and safety of suprascapular nerve block combined with axillary nerve block for arthroscopic shoulder surgery: A systematic review and meta-analysis of randomized controlled trials” [Int. J. Surg. 94 (2021) 106111

Abstract

Dear Editor, The incidence of severe postoperative pain after shoulder surgery is 30%–70% [1,2]. Postoperative pain should be relieved for early patient rehabilitation and recovery. Patient-controlled analgesia (PCA) with opiate therapy can control some postoperative pain, but it has side effects like nausea, vomiting, and dizziness, which can be severe enough to prevent early discharge from hospital. There are several regional blocks which can be used to control postoperative pain. Interscalene brachial plexus block (ISB) is the most effective regional blocks for shoulder surgery, but it sometimes causes complications such as phrenic nerve palsy. Suprascapular nerve block (SSNB) is another widely used method for relieving pain after shoulder surgery. Furthermore, axillary nerve block (ANB) is a newly adopted method for shoulder pain control. To study the efficacy and safety of SSNB combined with ANB for shoulder arthroscopic surgery, Zhao et al. [3] performed a systematic review and meta-analysis of nine randomized controlled trials and concluded that SSNB combined with ANB had advantages over SSNB alone in pain relief, patient satisfaction within 24 h after surgery and decreased incidence of dyspnea. ISB can provide excellent analgesia within the first postoperative 6 h after shoulder surgery. However, it poses a risk, especially to patients with lung pathology, as it leads to a 100% ipsilateral phrenic nerve block (hemidiaphragmatic paralysis). It can also cause rebound pain and sensory and motor block in lower brachial plexus (C7-T1) in addition to the shoulder area onto which surgery has been carried out. Even though the undesired effects of ISB can be prevented by applying a low local anesthetic concentration (0.125% bupivacaine) with a low volume (5–10mL), the risk to patients cannot be totally eliminated. Safer multimodal analgesia techniques are more logical to be implemented instead of ISB. SSNB combined with ANB is based on the multimodal analgesia concept. The posterosuperior area of shoulder joint is innervated by the suprascapular nerve, the anteroinferior area by the axillary nerve, and the anterosuperior area by the articular branch of lateral pectoral nerve (LPN). A recent cadaveric study showed that the articular branch of LPN innervating the shoulder joint was present in 67.4% of cases and suggested that surgeons should consider blocking the articular branch of LPN to obtain maximum block coverage for pain control after shoulder surgery [4]. Since the present meta-analysis showed no difference in postoperative pain relief between SSNB combined with ANB and ISB, a three-arm noninferiority trial by including a placebo group to evaluate the sensitivity and internal validation of the new treatment is required. Provenance and peer review Commentary, internally reviewed. Ethical approval None. Sources of funding Funding: National Natural Science Foundation of China (81860396). Author contribution Long Gao: writing. Abudousaimi Aimaiti: study design. Research registration unique identifying number (UIN) None. Trial registry number – ISRCTN None. Guarantor Long Gao. Conflicts of interest There was no conflict of interest.