Single Shot Interscalene Block with Liposomal Bupivacaine versus Non-Liposomal Bupivacaine in Shoulder Arthroplasty.

BACKGROUND: Regional anesthesia is a valuable component of multimodal pain control in total shoulder arthroplasty (TSA), and multiple interscalene block anesthetic options exist, including non-liposomal interscalene bupivacaine (NLIB) and liposomal interscalene bupivacaine (LIB). The purpose of the current of study was to compare pain control and opioid consumption within 48 hours postoperative in those undergoing TSA with either LIB or NLIB. METHODS: This was a retrospective cohort study at a single academic medical center including consecutive patients undergoing inpatient (>23-hour hospitalization) primary anatomic or reverse TSA from 2016 to 2020 who received either LIB or a NLIB for perioperative pain control. Perioperative patient outcomes were collected including pain levels and opioid usage, as well as 30- and 90-day ED visits or readmissions. The primary outcome was postoperative pain and opioid use. RESULTS: Overall, 489 patients were included in this study (316 LIB and 173 NLIB). Pain scores at 3, 6, 12, and 48 hours postoperatively were not statistically significantly different (p>0.05 for all). However, the LIB group had improved pain scores at 24- and 36-hours postoperative (p<0.05 all). There was no difference in the incidence of severe postoperative pain, defined as a 9 or 10 NRS-11 score, between the two anesthesia groups after adjusting for preoperative pain and baseline opioid use (OR: 1.25; 95% CI: 0.57-2.74; p=0.57). Overall, 99/316 (31.3%) of patients receiving LIB did not require any postoperative opioids compared with 38/173 (22.0%) receiving NLIB; however, this difference was not statistically significant after adjusting for prior opioid use and preoperative pain (p=0.33). No statistically significant differences in postoperative total morphine equivalents or mean daily morphine equivalents consumed between the groups were found during their hospital stays (p>0.05 for both). Finally, no significant differences in 30- and 90-day ED visits or readmission rates were found (all p>0.05). CONCLUSION: LIB and NLIB demonstrated differences in patient reported pain scores at 24- and 36-hours post operation, although these did not reach clinical significance. There were no statistically significant differences in opioid consumption during the hospital stay, including opioid use, total morphine equivalents and daily mean morphine equivalents consumed during the hospital stay. Additionally, no differences were observed in 30- and 90-day ED visits or readmission rates.

Interscalene block with liposomal bupivacaine versus continuous interscalene catheter in primary total shoulder arthroplasty.

BACKGROUND: Multimodal pain regimens in total shoulder arthroplasty (TSA) now include regional anesthetic techniques. Historically, regional anesthesia for extended postoperative pain control in TSA was administered using a continuous interscalene catheter (CIC). Liposomal bupivacaine (LB) is used for its potential for similar pain control and fewer complications compared with indwelling catheters. We evaluated the efficacy of interscalene LB compared with a CIC in postoperative pain control for patients undergoing TSA. METHODS: This was a retrospective cohort study at a tertiary-care academic medical center including consecutive patients undergoing primary anatomic or reverse TSA from 2016 to 2020 who received either single-shot LB or a CIC for perioperative pain control. Perioperative and outcome variables were collected. The primary outcome was postoperative pain control, whereas the secondary outcome was health care utilization. RESULTS: The study included 565 patients, with 242 in the CIC cohort and 323 in the LB cohort. Demographic characteristics including sex (P = .99) and race (P = .81) were similar between the cohorts. The LB cohort had significantly lower mean pain scores at 24 hours (3 vs. 2, P < .001) and 36 hours (3 vs. 2, P < .001) postoperatively. The CIC cohort showed a higher percentage of patients experiencing a pain score of 9 or 10 postoperatively (29% vs. 17%, P = .001), whereas the LB cohort had a significantly greater proportion of opioid-free patients (32% vs. 10%, P < .001). Additionally, a greater proportion of CIC patients required opioid escalation to patient-controlled analgesia (7% vs. 2%, P = .002). The CIC cohort experienced a greater length of stay (2.3 days vs. 2.1 days, P = .01) and more 30-day emergency department visits (5% vs. 2%, P = .038). CONCLUSIONS: LB demonstrated lower mean pain scores at 24 and 36 hours postoperatively and lower rates of severe postoperative pain. Additionally, LB patients showed significantly higher rates of opioid-free pain regimens. These results suggest that as part of a multimodal pain regimen in primary shoulder arthroplasty, LB may provide greater reductions in pain and opioid use when compared with CICs.

Opening injection pressure consistently detects needle-nerve contact during ultrasound-guided interscalene brachial plexus block.

BACKGROUND: Needle trauma may cause neuropathy after nerve blockade. Even without injection, nerve injury can result from forceful needle-nerve contact (NNC). High opening injection pressures (OIPs) have been associated with intrafascicular needle tip placement and nerve damage; however, the relationship between OIP and NNC is unclear. The authors conducted a prospective, observational study to define this relationship. METHODS: Sixteen patients scheduled for shoulder surgery under interscalene block were enrolled if they had clear ultrasound images of the brachial plexus roots. A 22-gauge stimulating needle was inserted within 1 mm of the root, and 1-ml D5W injected at 10 ml/min by using an automated pump. OIP was monitored using an in-line pressure manometer and injections aborted if 15 psi or greater. The needle was advanced to displace the nerve slightly (NNC), and the procedure repeated. Occurrence of evoked motor response and paresthesia were recorded. RESULTS: Fifteen patients had at least one clearly visible root. OIP at 1 mm distance from the nerve was less than 15 psi (mean peak pressure 8.2 ± 2.4 psi) and the 1-ml injection could be completed in all but two cases (3%). In contrast, OIP during NNC was 15 psi or greater (mean peak pressure 20.9 ± 3.7 psi) in 35 of 36 injections. Aborting the injection when OIP reached 15 psi prevented commencement of injection in all cases of NNC except one. CONCLUSION: High OIP (≥15 psi) consistently detected NNC, suggesting that injection pressure monitoring may be useful in preventing injection against nerve roots during interscalene block.

Low interscalene block provides reliable anesthesia for surgery at or about the elbow.

STUDY OBJECTIVE: To determine whether interscalene brachial plexus block (ISB) provides adequate anesthesia for surgery on or about the elbow. STUDY DESIGN: Case series. SETTING: Operating room of an academic teaching hospital. PATIENTS: 78 patients scheduled for elective elbow surgery. INTERVENTIONS: All patients received an ISB using a low approach technique. A stimulating needle was inserted in the interscalene groove two cm above the clavicle. A volume of 35-45 mL of mepivacaine 1.5% or ropivacaine 0.5% was administered after obtaining a motor response of any component of the brachial plexus with a current intensity of 0.2-0.4 mA (0.1 msec). MEASUREMENTS: Block success rate, defined as the ability to complete surgery without use of intraoperative opioids or general anesthesia, was assessed. Verbal rating scores for pain (0 = no pain, 10 = worst pain imaginable) were obtained in the recovery room. MAIN RESULTS: Low ISB resulted in successful surgical anesthesia in 75 (96%) of the study patients. Verbal rating scores were low (0-2) for all patients postoperatively. CONCLUSIONS: The low interscalene block can be used to provide surgical anesthesia in the majority of patients having surgery on or about the elbow.