Interscalene Brachial Plexus Catheter Versus Single-shot Interscalene Block with Periarticular Local Infiltration Analgesia for Shoulder Arthroplasty

Background: Interscalene brachial plexus block is a commonly employed regional anesthetic technique for total shoulder arthroplasty, and a continuous catheter is often placed to extend the analgesic benefit of the block. As periarticular local infiltration analgesia (LIA) for total joint arthroplasty is a re-emerging trend, we evaluated the analgesic efficacy of continuous interscalene block (CISB) compared to single-shot interscalene block (SSISB) with LIA.

Methods: We conducted a retrospective review of 130 consecutive patients treated by one surgeon in a single institution, with 12 patients excluded for history of chronic opioid tolerance and two for incomplete data. The SSISB with LIA treatment group (N.=53) was compared to a control group who received CISB (N.=63). Primary end points were a difference in pain score (0-10 numeric rating scale) and opioid requirements as oral morphine equivalents (OMEs) on postoperative days (PODs) 0 and 1. Secondary end points included nausea and vomiting, length of hospital stay, block failure rate, adverse events due to block, and 30-day readmission.

Results: When compared to SSISB with LIA, patients who received CISB exhibited decreased opioid requirements in OMEs on POD 0 (11.9 mg vs. 28.7 mg, P<0.01) and POD 1 (24.0 mg vs. 50.3 mg, P<0.01). There was no significant difference in pain on POD 0, but a statistically significant decrease in average pain scores with CISB on POD 1 (2.3 vs. 4.3, P<0.01).

Conclusions: SSISB with LIA may provide clinically similar postoperative analgesia compared to CISB, but with escalating doses of opioid requirements.