Background: Shoulder arthroplasty is associated with significant postoperative pain. Interscalene plexus block is the gold standard for pain management in patients undergoing this surgery, however, alternatives are currently being developed. We hypothesized that a combination of anterior suprascapular nerve block and lateral sagittal infraclavicular block would provide effective postoperative analgesia. Primary aims for this study were to document numeric rating scale (NRS) pain score and use of oral morphine equivalents (OMEq) during the first 24 hours after surgery. Secondary aim was to determine the incidence of hemidiaphragmatic paralysis.
Methods: Twenty patients (ASA physical status I-III) scheduled for shoulder arthroplasty were studied. Four ml ropivacaine 0.5% was administered for the suprascapular nerve block and 15 ml ropivacaine 0.75% for the infraclavicular block. Surgery was performed under general anaesthesia. Paracetamol and prolonged-release oxycodone were prescribed as postoperative analgesics. Morphine and oxycodone were prescribed as rescue pain medication. Diaphragm status was assessed by ultrasound.
Results: Median NRS (0-10) at 1, 3, 6, 8 and 24 hours postoperatively were 1, 0, 0, 0 and 3, respectively. NRS at rest during the first 24 postoperative hours was 4 (2.5-4.5 [0-5]), median (IQR [range]). Maximum NRS was 6.5 (5-8 [0-10]) median (IQR [range]). Total OMEq during the first 24 postoperative hours was 52.5 mg (30-60 [26.4-121.5]) median (IQR [range]). Hemidiaphragmatic paralysis was diagnosed in one patient (5%).
Conclusions: The combination of suprascapular and infraclavicular nerve block shows an encouraging postoperative analgesic profile and a low risk for hemidiaphragmatic paralysis after total shoulder arthroplasty.
Keywords: athroplasty; diaphragm; infraclavicular block; postoperative analgesia; regional anaesthesia; shoulder surgery; suprascapular block.