Interscalene Nerve Block for Shoulder Arthroscopy May Decrease Opioid Use and Improve Pain Scores

For shoulder arthroscopy, preoperative ultrasound-guided interscalene nerve block reduced intraoperative opioid and sevoflurane use according to results of a retrospective observational study published in the Journal of Pain Research.

According to the study authors, “Ultrasound-guided interscalene nerve block (UISB) can reduce opioid-related adverse effects such as pruritus, nausea, vomiting, consciousness disturbance, and constipation.” 

Patients (N=142) who underwent shoulder arthroscopy at the Kaohsiung Chang Gung Memorial Hospital in Taiwan in 2019 were retrospectively evaluated for opioid consumption and pain outcomes on the basis of whether they underwent preoperative ultrasound-guided interscalene nerve block (n=74) or not (n=68).

The median ages of patients in the intervention and control cohorts were 60.5 (interquartile range [IQR], 50.8-67.3) and 56.5 (IQR, 47.5-61.0) years (P =.033). Most patients were indicated as being American Society of Anesthesiologists classification II (79.7% for the intervention cohort and 80.9% for the control cohort).

Median duration of anesthesia was 2.25 hours for patients undergoing ultrasound-guided interscalene nerve block and 2.14 hours for patients in the control cohort (P =.337). Opioid consumption was lower in the intervention group compared with the control group (median morphine milligram equivalent [MME], 0.056 vs 0.108 mg. respectively; P <.001), as was consumption of sevoflurane (0.201 vs 0.236 mL/kg/h; P =.001).

Although participants undergoing ultrasound-guided interscalene nerve block consumed fewer opioids than participants in the control group while in the postanesthesia care unit (PACU; median MME, 0.007 vs 0.015 mg; P =.055), they consumed a similar amount of opioids while in the ward (median MME, 0.050 vs 0.049 mg; P =.761).

Pain scores on a Visual Analogue Scale (VAS) were lower among participants in the intervention cohort while in the PACU (median, 0.5 vs 3.0; P <.001) and with movement while in the ward (median, 2.0 vs 3.0; P <.001).

No group differences were reported for satisfaction associated with anesthesia; duration of hospital stay; or postoperative dizziness, nausea, or vomiting (all P ≥.311).

A limitation of this study is its retrospective observational design.

These data indicate that ultrasound-guided interscalene nerve block performed prior to shoulder arthroscopy may reduce opioid consumption and improve pain outcomes. This approach may be an effective opioid-sparing multimodal analgesia in the setting of shoulder arthroscopy.