Cite as: Grzybowski J, Rayaz H, Thai CP, et al. Literature review - August 2026. ASRA Pain Medicine News 2026;51. https://doi.org/10.52211/asra080126.015

Acute Pain

The Chitranjan S. Ranawat Award: Surgeon-Performed, Intraoperative Adductor Canal Blocks are Non-Inferior to Anesthesiologist-Performed Adductor Canal Blocks in Total Knee Arthroplasty

Benavides B et al. J Arthroplasty 2026;41(S17):S11-S17.e1.https://doi.org/10.1016/j.arth.2026.04.105

Summary by Jeffrey Grzybowski, MD

Introduction: Adductor canal blocks (ACBs) are a recommended component of analgesia for outpatient total knee arthroplasties (TKA). Routine incorporation of ACBs in perioperative workflow may increase case times and costs and require specialized anesthesiologists who are of limited availability in resource-constrained centers. This randomized controlled trial aims to evaluate whether surgeon-performed ACBs (sACBs) are non-inferior to anesthesiologist-performed ACBs (aACBs) regarding time to discharge, perioperative outcomes, and patient-reported outcome measures (PROMs).

Methods: Patients randomized to the aACB group received a preoperative single-shot, ultrasound-guided ACB performed by an anesthesiologist using 15 mL of 0.25% ropivacaine with epinephrine immediately prior to a spinal anesthetic. Patients in the sACB group received spinal anesthesia and following implantation, received an ACB by the surgeon using a standardized, landmark-based technique with identical local anesthetic volume and concentration. All patients received surgeon-performed periarticular infiltration containing 0.2% ropivacaine, 0.5 mg epinephrine, and 30 mg ketorolac. Postoperative discharge prescriptions were standardized. The primary outcome was time to discharge, defined as the time between documented complete reversal of the spinal anesthetic and meeting all surgical discharge criteria, per institutional policy.

Results: 200 patients were analyzed in the study. The difference in time to discharge between the two groups was not significantly different, with a mean time to discharge of 233.1 minutes in the aACB group and 209.5 minutes in the sACB group, P=0.06. The numeric pain rating scale at discharge was aACB: 2.4 compared to sACB: 2.9, P=0.07. Total 24-hour opioid consumption measured in MME also demonstrated no significant difference: aACB: 35.8 MME versus sACB: 43.6, P=0.31.

Key Point: This study demonstrates that sACBs are noninferior to aACB in outpatient TKA in time to discharge, and comparable perioperative outcomes and early PROMs exist for both methods.

Pericapsular Nerve Group (PENG) Block at 10 mL vs. 20 mL for Postoperative Analgesia After Total Hip Arthroplasty: A Randomized Controlled Trial

Aliş G, Özden MGN, Karaoğlu. BMC Anesthesiol 2026;26(1):416. https://doi.org/10.1186/s12871-026-03923-8

Summary by Hassan Rayaz, MD

Introduction: The pericapsular nerve group (PENG) nerve block is increasingly used for analgesia in hip surgery. The optimal dose, however, has not yet been fully established. This study investigates if 10 mL of 0.25% bupivacaine is non-inferior to 20 mL of 0.25% bupivacaine.

Methods: This is a single-center randomized controlled non-inferiority trial comparing PENG blocks using 10 mL of 0.25% bupivacaine versus 20 mL of 0.25% bupivacaine. The primary outcome was the numerical rating scale (NRS) pain score at rest one hour into the postoperative period. A non-inferiority margin of 1 NRS point was prespecified. Secondary outcomes included opioid related side effects, quadriceps weakness, postoperative nausea/vomiting, patient satisfaction, and length of stay. Outcome assessors, data analysts, post-anesthesia care unit staff, and postoperative floor staff were all blinded to the dose being administered. The patients involved in the study were monitored and evaluated for 24 hours postoperatively. The same anesthesiologist conducted the blocks.

Results: There were 50 patients enrolled in the study with 25 randomized to each group. For the primary outcome of 1-hour resting NRS, the between group difference (10 mL-20 mL) was 0 (95% CI -0.6 to 0.6). Since the lower bound remained above the noninferiority margin of -1, the 10 mL PENG block demonstrated non-inferiority. Secondary outcomes did not differ significantly between groups during the first 24 postoperative hours.

Key Point: This study concludes that injecting 10 mL of 0.25% bupivacaine has non-inferior pain coverage to 20 mL of 0.25% bupivacaine.

Duration of Analgesia After Supraclavicular Brachial Plexus Block with Intravenous Dexamethasone with or without Dexmedetomidine: A Randomized, Placebo-Controlled, Triple Blind Trial

Grape S et al. Br J Anaesth 2026;136(5):1588-94.https://doi.org/10.1016/j.bja.2025.10.049

Summary by Carolyn P. Thai, DO

Introduction: Intravenous (IV) dexamethasone and dexmedetomidine are commonly used adjuncts to prolong analgesia following peripheral nerve blocks. Determining whether the combination improves analgesia duration is clinically important because longer analgesia may reduce opioid consumption and improve postoperative recovery. This study evaluated whether adding IV dexmedetomidine to IV dexamethasone prolongs postoperative analgesia after a supraclavicular block.

Methods: In this randomized, triple-blind, placebo-controlled trial, 100 adult patients (ASA I-III) undergoing upper extremity surgery received an ultrasound-guided supraclavicular block with a mixture of 0.5% mepivacaine and 0.25% ropivacaine. After block completion, all participants received IV dexamethasone (0.15 mg/kg) followed by a 10-minute infusion of either placebo (normal saline) or IV dexmedetomidine (1 mcg/kg). Participants, physicians, recovery nurses, and personnel involved in data collection and interpretation were blinded to group allocation. Participants were followed postoperatively at 4, 24, and 48 hours and 7 days. The primary outcome was duration of analgesia defined as the time from block completion to first oral opioid intake. Secondary outcomes included sensory and motor block duration, pain scores, overall opioid consumption, patient satisfaction, and adverse events.

Results: 99 participants were included in the analysis. The mean duration of analgesia was 621 + 334 minutes in the dexamethasone group and 690 + 544 minutes in the dexamethasone and dexmedetomidine group with no significant difference found (P=0.47). No significant differences were observed in secondary outcomes. No clinically significant adverse events were reported.

Key Point: Adding IV dexmedetomidine to dexamethasone after a supraclavicular block does not improve analgesia duration, pain scores, overall opioid consumption, or patient satisfaction.

Chronic Pain

The Veterans Affairs’ Whole Health Approach for Chronic Pain Management: The wHOPE Randomized Clinical Trial

Seal KH et al. JAMA 2026;335(20):1774-86. 10.1001/jama.2026.5006

Summary by Enas Kandil, MD, MSc

Introduction: A randomized clinical trial was conducted at six Veterans Affairs (VA) health systems (2020-2025) to test whether the VA’s “Whole Health” model improves chronic pain outcomes compared to cognitive behavioral therapy (CBT) and usual care. It is the first RCT to test this congressionally mandated approach.

Methods: Participants with moderate to severe chronic pain in the VA system were randomized into three groups: 1) Whole Health team (n=343) involving physician/nurse practitioner, integrative care clinician (eg, acupuncturist, physiotherapist), wellness coach (5 visits and 8 coaching sessions); 2) CBT (n=339) involving 7 group sessions teaching pain self-management skills; or 3) Usual care (n=82) involving standard VA stepped pain care. The primary outcome was brief pain inventory interference score (0–10 scale) at 12 months.

Results: A total of 764 veterans were randomized to the three groups in a 11:11:2 fashion. The Whole Health group had significantly improved pain interference scores (from 6.6 to 4.9) compared with the CBT (from 6.4 to 5.5) (mean difference, -0.58 [97% CI, -1.11 to -.0.5]; P = 0.02) and usual care (from 6.4 to 5.7) (mean difference, -0.77 [99%CI, -1.4 to -0.15] P=0.002) groups. CBT did not significantly improve pain interference scores compared with usual care. Suicidal ideation was the most common adverse event with similar rates of occurrence across groups (13.4%-15.9%).

Key Point: Whole-team care resulted in a statistically significant, but clinically modest, improvement in pain interference compared with CBT and usual care.

Comparative Efficacy of Scalene versus Scapular Approach for Ultrasound-Guided Corticosteroid Hydrodissection in Dorsal Scapular Nerve Entrapment: A Randomized Controlled Trial

Elawamy AM, Lam KHS, Allam AE, et al. J Pain Res 2026;19:576439. https://doi.org/10.2147/JPR.S576439

Summary by Yian Chen, MD

Introduction: Dorsal scapular nerve (DSN) entrapment is a common cause of unilateral neck root and interscapular pain. There are two common approaches to hydrodissection for DSN entrapment. This study aimed to compare the short-term efficacy of the scalene versus scapular approach for DSN steroid hydrodissection.

Methods: A prospective, multicenter randomized controlled trial was carried out through treatment facilities in Egypt; both patients and evaluators, but not proceduralists, were blinded. Patients with DSN entrapment were randomized to ultrasound-guided hydrodissection with lidocaine 2% 2ml and triamcinolone 40mg at 1) the middle scalene muscle or 2) below the levator scapulae. Resting visual analog scores (VAS) [primary outcome], VAS during movement, fatigue assessment scale (FAS), patient satisfaction, and motor distal latency were assessed at baseline, 1 month, and 3 months.

Results: Sixty patients with DSN entrapment were randomized to 30 participants each in scalene and scapular study arms. VAS at rest were lower at 1 and 3 months in the scalene group than in the scapular group (Z=6.68 at both time points, p<0.001). VAS on movement, FAS scores, and patient satisfaction were also found to be improved in the scalene group (p<0.001). No major complications were observed in either group.

Key Point: Ultrasound-guided hydrodissection at the middle scalene led to more significant improvements in pain scores as well as fatigue and pain satisfaction compared to the scapular approach.

The Effects of Neuromodulation Through Brainwave Entrainment on Pain in Women with Fibromyalgia: A Randomized Controlled Clinical Trial with Follow-Up

de Souza G, Daux Buffon L, Hardt da Silva R, et al.. Pain Med 2026;pnag064. https://doi.org/10.1093/pm/pnag064

Summary by Vandana Sharma, MD, FASA

Introduction: Fibromyalgia may affect the resting brain electrical wave patterns. Non-pharmacologic adjuncts have not been well studied in this patient population. This trial evaluated whether brainwave entrainment (BWE) provides greater benefit in pain relief and quality of life measures than music therapy in women with fibromyalgia.

Methods: This double-blind, randomized, placebo-controlled clinical trial enrolled 96 women diagnosed with fibromyalgia based on 2016 American College of Rheumatology criteria. The intervention group underwent BWE therapy using binaural beats and visual stimulation for 20-minute sessions, 5 times per week for 8 weeks, during which alpha and theta frequency protocols were administered. The control group underwent music therapy (MT) using the same treatment schedule and therapist contact time. The primary outcome was pain assessment using a visual analog scale) during weekly treatment and at 3 and 6 months post-treatment. Secondary outcomes included evaluation of quality of life, depression, and biomarkers of oxidative stress.

Results: There was no difference in baseline characteristics between the groups. The BWE group experienced reduced pain (p=0.0001) at follow-ups compared to baseline but not statistically significantly different when compared to MT. BWE improved parameters related to quality of life (BWE p=0.002 vs MT p=0.035), depression (BWE p=0.0001 vs MT p=0.006), and oxidative stress, and reduced brain-derived neurotrophic factor (BWE p=0.049 vs MT p=0.030) levels in patients with fibromyalgia, but was not statistically significantly different when compared with MT.

Key Point: This trial supports brainwave entrainment as a promising adjunctive non-pharmacologic therapy for fibromyalgia, but larger trials are needed to confirm the effectiveness.