Philip Peng

Introduction: Axillary nerve blockade contributes to selective shoulder analgesia while minimizing phrenic nerve involvement. However, reliable ultrasound-guided approaches remain undefined. We evaluated dye spread following a novel ultrasound-guided trans-quadrangular space approach targeting the axillary nerve in a cadaveric simulation study. Methods: 12 ultrasound-guided trans-quadrangular space injections using 7 mL of methylene blue were performed in six fresh, unembalmed cadavers positioned laterally. The needles were inserted into the quadrangular space with a posterior approach. Dissections were conducted 15 min after injection using a standardized protocol. The primary outcome was the frequency and degree of staining of the axillary nerve trunk and its anterior and posterior divisions. Secondary outcomes included staining of the radial nerve, musculocutaneous nerve, and posterior cord. Results: The main axillary nerve trunk demonstrated consistent staining in 100% (12/12) of injections. At the branching point, the anterior and posterior divisions were stained in 83% (10/12) and 90% (11/12) of injections, respectively. The radial nerve was lightly stained in 25% (3/12) of injections. No staining of the musculocutaneous nerve or posterior cord was observed. In all injections, dye tracking extended longitudinally within the quadrangular space and slightly beyond the nerve’s entrance at anterior quadrangular space. Conclusion: The ultrasound-guided trans-quadrangular space approach consistently stained the axillary nerve trunk and divisions with minimal unintended spread. This posterior technique, performed in the lateral position without shoulder abduction, demonstrates anatomical feasibility and may support further clinical investigation of selective axillary nerve blockade.

Adhesive capsulitis, or frozen shoulder, is characterized by pain and progressive restriction of both active and passive shoulder range of motion. The pathophysiology involves an initial inflammatory phase with elevated cytokines, followed by pathological fibrosis, capsular thickening, and contracture involving both intra- and extra-articular structures, including the coracohumeral ligament and rotator cuff interval. Diagnosis is primarily clinical. The traditional three-stage model, freezing, frozen, and thawing, has been challenged by recent evidence showing that spontaneous recovery is uncommon and that many patients do not fully regain shoulder function without active treatment. This paradigm change emphasizes the necessity of early and focused interventions to maximize functional recovery. While physiotherapy remains the mainstay of management, interventional procedures have gained prominence for their ability to reduce pain and facilitate rehabilitation. Interventional options include intra-articular corticosteroid injections, hydrodilatation, and suprascapular nerve blocks. This narrative review summarizes current evidence on interventional procedures for adhesive capsulitis, highlighting their mechanisms, techniques, and comparative efficacy.

Objective This case series aims to assess the analgesic effectiveness and safety of percutaneous chemical denervation of the articular branches on anterior hip capsule in patients with refractory hip pain secondary to avascular necrosis (AVN). Methods Nine patients with refractory chronic hip pain secondary to AVN underwent image-guided chemical neurolysis with 100% ethanol. Average pain scores were recorded at baseline, 1, 3 and 6 months after chemical neurolysis. Results The average baseline pain score was 6.7±1.2 on the Numerical Rating Scale (NRS). Two out of the nine patients did not respond to chemical neurolysis. For the seven patients who responded, the average NRS decreased to (2.9±1.2) at 1 month and (3.0±1.4) at 3 months. Five out of these seven patients maintained 50% or greater pain relief at both 1 and 3 months. For the five patients who completed the 6-month follow-up, the average NRS pain score was (3.0±1.7), with three of these patients maintaining 50% or greater pain relief. No one reported side effects or complications during the follow-up period. Conclusions In conclusion, alcohol neurolysis of the hip joint can be offered as an effective and safe modality for pain control in patients with AVN who failed conservative management. This small case series serves as a pilot for future large cohort studies.

Chronic knee joint pain affects millions worldwide, with radiofrequency ablation (RFA) of genicular nerves emerging as a potential treatment in the last 15 years. Despite its growing popularity, with studies demonstrating its efficacy in pain reduction for up to 12 months, recent randomized controlled trials have questioned the efficacy of RFA. Discrepancies in study results may partially be explained by the heterogeneity of patient selection and technical protocols. This daring discourse aims to explore and critically analyze the ongoing debates surrounding RFA of the genicular nerves, addressing key controversies, namely: (1) Is there a role for performing prognostic blocks prior to RFA?; (2) What are the optimal target sites for final cannulae placement for the classical targets?; (3) Which and how many nerves should be targeted in RFA procedures?; (4) What are the comparative benefits of using ultrasound versus fluoroscopy guidance, and whether a combined technique may be advantageous?; (5) Is there a potential role for pulsed radiofrequency of the genicular nerves?; (6) Should genicular nerve RFA be performed after total knee arthroplasty? Through this in-depth discussion, we aim to guide pain medicine clinicians in informed decision-making and encourage further research in this field.

Innervation of the shoulder joint is complex and remains poorly understood among regional anesthesiologists and chronic pain specialists. Current literature supports the important contribution of the axillary nerve to the total innervation of the shoulder, as well as its blockade for perioperative pain and denervation for chronic shoulder pain. However, a description of the entire course of the axillary nerve, the corresponding optimal targets, and the sonoanatomy pertinent to pain intervention is lacking. This educational article discusses in detail the functional anatomy and sonographic identification of possible windows for axillary nerve intervention. We discuss the contribution, extent, and type of innervation the axillary nerve provides to the shoulder joint, which is often misunderstood. Ultimately, this article serves to stimulate thoughts and ideas for future research in an area where literature is scarce.

This educational article discusses the current understanding of the pericaspular nerve group block (PENG) of the hip regarding its mechanism of action and spread patterns, as well as plausible explanations for postblock quadriceps weakness. Finally, we will discuss the recent evidence of PENG block as an analgesic block in hip fractures and in different hip surgeries.

Background Inconsistent nomenclature and anatomical descriptions of regional anesthetic techniques hinder scientific communication and engender confusion; this in turn has implications for research, education and clinical implementation of regional anesthesia. Having produced standardized nomenclature for abdominal wall, paraspinal and chest wall regional anesthetic techniques, we aimed to similarly do so for upper and lower limb peripheral nerve blocks. Methods We performed a three-round Delphi international consensus study to generate standardized names and anatomical descriptions of upper and lower limb regional anesthetic techniques. A long list of names and anatomical description of blocks of upper and lower extremities was produced by the members of the steering committee. Subsequently, two rounds of anonymized voting and commenting were followed by a third virtual round table to secure consensus for items that remained outstanding after the first and second rounds. As with previous methodology, strong consensus was defined as ≥75% agreement and weak consensus as 50%–74% agreement. Results A total of 94, 91 and 65 collaborators participated in the first, second and third rounds, respectively. We achieved strong consensus for 38 names and 33 anatomical descriptions, and weak consensus for five anatomical descriptions. We agreed on a template for naming peripheral nerve blocks based on the name of the nerve and the anatomical location of the blockade and identified several areas for future research. Conclusions We achieved consensus on nomenclature and anatomical descriptions of regional anesthetic techniques for upper and lower limb nerve blocks, and recommend using this framework in clinical and academic practice. This should improve research, teaching and learning of regional anesthesia to eventually improve patient care.