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.

The relative analgesic value of a femoral nerve block versus adductor canal block following total knee arthroplasty: a randomized, controlled, double-blinded study.

BACKGROUND: Multiple comparative studies report that adductor canal blocks provide similar pain relief to femoral nerve blocks following total knee arthroplasty. However, adductor canal blockade fails to anesthetize several important femoral nerve branches that contribute to knee innervation. We sought to clarify this anatomic discrepancy by performing both blocks in sequence, using patients as their own controls. We hypothesized that patients would experience additional pain relief following a superimposed femoral nerve block, demonstrating that these techniques are not equivalent. METHODS: Sixteen patients received continuous adductor canal block before undergoing knee arthroplasty under general anesthesia. In the recovery room, patients reported their pain score on a numeric scale of 0-10. Once a patient reached a score of five or greater, he/she was randomized to receive an additional femoral nerve block using 2% chloroprocaine or saline sham, and pain scores recorded every 5 min for 30 min. Patients received opioid rescue as needed. Anesthesiologists performing and assessing block efficacy were blinded to group allocation. RESULTS: Patients randomized to chloroprocaine versus saline reported significantly improved median pain scores 30 min after the femoral block (2.0 vs. 5.5, P = 0.0001). Patients receiving chloroprocaine also required significantly fewer morphine equivalents during the 30 min post-femoral block (1.0 vs. 4.5 mg, P = 0.03). CONCLUSIONS: Adductor canal block is a useful technique for postoperative pain following total knee arthroplasty, but it does not provide equivalent analgesic efficacy to femoral nerve block. Future studies comparing efficacy between various block sites along the thigh are warranted.

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.

The effects of ultrasound-guided adductor canal block versus femoral nerve block on quadriceps strength and fall risk: a blinded, randomized trial of volunteers.

BACKGROUND AND OBJECTIVES: Adductor canal block (ACB) has been suggested as an analgesic alternative to femoral nerve block (FNB) for procedures on the knee, but its effect on quadriceps motor function is unclear. We performed a randomized, blinded study to compare quadriceps strength following adductor canal versus FNB in volunteers. Our hypothesis was that quadriceps strength would be preserved following ACB, but not FNB. Secondary outcomes included relative preservation of hip adduction and degree of balance impairment. METHODS: The ACB was performed in one leg and the FNB in the contralateral leg in 16 volunteers using a randomized block sequence. For all blocks, 15 mL of 3% chloroprocaine was injected under ultrasonographic guidance. Maximal voluntary isometric contraction of knee extension and hip adduction was measured at baseline and at 30 and 60 minutes after block. After 60-minute assessments were complete, the second block was placed. A test of balance (Berg Balance Scale) was performed 30 minutes after the first block only. RESULTS: Quadriceps strength and balance scores were similar to baseline following ACB. Following FNB, there was a significant reduction in quadriceps strength (95.1% ± 17.1% vs 11.1% ± 14.0%; P < 0.0001) and balance scores (56 ± 0 vs 37 ± 17.2; P = 0.02) compared with baseline. There was no difference in hip adductor strength (97.0% ± 10.8% vs 91.8% ± 9.6%; P = 0.17). CONCLUSIONS: Compared with FNB, ACB results in significant quadriceps motor sparing and significantly preserved balance.

The effect of stimulating versus conventional perineural catheters on postoperative analgesia following ultrasound-guided femoral nerve localization.

STUDY OBJECTIVE: To test the hypothesis that, if the femoral nerve is correctly localized using ultrasound (US) guidance, the type of perineural catheter used has no effect on catheter success. DESIGN: Randomized controlled trial. SETTING: Post-anesthesia care unit of an academic teaching hospital. PATIENTS: 40 ASA physical status 1, 2, and 3 patients, ages 55-85 years, undergoing elective total knee arthroplasty. INTERVENTIONS: All patients received postoperative continuous femoral nerve blocks and a single injection sciatic nerve block. Nerve localization was accomplished using US guidance and electrical nerve stimulation so that the needle tip was visualized deep to the femoral nerve. Patients were randomized to receive either stimulating (Group SC) or nonstimulating catheters (Group NSC) in the usual manner for each device. Catheters were bolused with ropivacaine and an infusion commenced. MEASUREMENTS: The primary outcome was quality of analgesia (as measured by a numerical rating scale). Other outcomes included sensory block success rate, number of attempts and time required to localize the needle tip correctly, number of attempts and time required to place the perineural catheter, amount of local anesthetic and opioid use postoperatively, and degree of completion of preset postoperative rehabilitation goals. MAIN RESULTS: Quality of analgesia was similar at all time intervals. Rates of successful femoral block (95% vs 80%; P = 0.34) were similar between groups. Time required to position the catheter was greater in Group SC than Group NSC (3.45 ± 2.05 min vs 1.72 ± 0.88 min; P < 0.01). CONCLUSIONS: Ultrasound guidance for needle localization prior to catheter insertion for femoral nerve block results in similar block characteristics between stimulating and nonstimulating catheters. The use of nonstimulating catheters avoids the technical challenges of stimulating catheters and does not require additional helpers.

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.

Lumbar plexus block using high-pressure injection leads to contralateral and epidural spread.

BACKGROUND: The main advantage of lumbar plexus block over neuraxial anesthesia is unilateral blockade; however, the relatively common occurrence of bilateral spread (up to 27%) makes this advantage unpredictable. The authors hypothesized that high injection pressures during lumbar plexus block carry a higher risk of bilateral or neuraxial anesthesia. METHODS: Eighty patients undergoing knee arthroscopy (age 18-65 yr; American Society of Anesthesiologists physical status I or II) during a standard, nerve stimulator-guided lumbar plexus block using 35 ml mepivacaine, 1.5%, were scheduled to be studied. Patients were randomly assigned to receive either a low-pressure (< 15 psi) or a high-pressure (> 20 psi) injection, as assessed by an inline injection pressure monitor (BSmart; Concert Medical LLC, Norwell, MA). The block success rate and the presence of bilateral sensory and/or motor blockade were assessed. RESULTS: An interim analysis was performed at n = 20 after an unexpectedly high number of patients had neuraxial spread, necessitating early termination of the study. Five of 10 patients (50%) in the high-pressure group had a neuraxial block with a dermatomal sensory level T10 or higher. In contrast, no patient in the low-pressure group (n = 10) had evidence of neuraxial spread. Moreover, 6 patients (60%) in the high-pressure group demonstrated bilateral sensory blockade in the femoral distribution, whereas no patient in the low-pressure group had evidence of a bilateral femoral block. CONCLUSIONS: Injection of local anesthetic with high injection pressure (> 20 psi) during lumbar plexus block commonly results in unwanted bilateral blockade and is associated with high risk of neuraxial blockade.

Acute upper airway angioedema secondary to acquired C1 esterase inhibitor deficiency: a case report.

PURPOSE: Adverse reactions to local anesthetics are widely reported. We report a case of acute upper airway angioedema presumed to be due to the local anesthetic articaine, which was subsequently diagnosed as acquired C1 esterase inhibitor deficiency. CLINICAL FEATURES: A 54-yr-old woman presented with a history of progressive facial and periorbital edema 24 hr after receiving articaine local anesthetic for a dental procedure. She was in mild respiratory distress but was not stridorous. After inhalational induction with sevoflurane in the operating room, direct laryngoscopy revealed marked edema of supraglottic structures including epiglottis, uvula and aryepiglottic folds and the larynx was not visualized. The patient's trachea was intubated under direct laryngoscopy. Seventy-two hours later, the endotracheal tube was removed and she made an uneventful recovery. Initially, the angioedema was thought to be caused by a hypersensitivity reaction to articaine. Later investigations showed normal C3 complement level, very low C4 complement and C1 esterase inhibitor levels confirming a diagnosis of C1 esterase inhibitor deficiency. Subsequently, the patient was started on androgen therapy. Her C1 esterase inhibitor level normalized and she remained symptom free nine months after initial presentation. CONCLUSION: We report a case of acute upper airway angioedema secondary to C1 esterase inhibitor deficiency requiring emergency airway management. Anesthesiologists should consider C1 esterase inhibitor deficiency in the differential diagnosis of patients with airway edema and be familiar with the acute and prophylactic treatment of patients with this diagnosis.