Percutaneous Coracohumeral Release for Patients with Adhesive Capsulitis: Two-Year Results from a Randomized Control Crossover Study.

BACKGROUND: Adhesive capsulitis (AC) causes a variety of symptoms, including but not limited to pain, stiffness, and a gradual restriction of active and passive range of motion (ROM). The coracohumeral ligament (CHL) plays an important role in this disease process, and percutaneous CHL release (PCHLR) has demonstrated efficacy in treating manifestations of this disorder that are refractory to pain medication, physical therapy, and local injections. Our previous study demonstrated one-year efficacy and durability, and this study examines 2-year data from our original randomized control crossover cohort. OBJECTIVE: To highlight the importance of extended follow-ups evaluating PCHLR's efficacy in AC management. STUDY DESIGN: A prospective, randomized, controlled, cross-over trial. SETTING: An academic medical center. METHODS: Patients with AC refractory to oral medication, physiotherapy, and at least one local injection were included in our original study. In all, there were initially 40 patients (46 shoulders), including 6 patients who underwent bilateral PCHLR using the Tenex® system. In this prospective study, 2 groups, the experiment group (scheduled to receive PCHLR) and the control group (scheduled to receive a local anesthetic in the coracohumeral ligament [LACHL]) were determined through 2-to-1 block randomization. Of these 46 shoulders initially treated, 39 remained in the study at one year. Twenty-six of the 39 shoulders were assigned to the PCHLR group whereas 13 were assigned to the LACHL group. Nine out of 13 shoulders in the LACHL group crossed over to the PCHLR group. Ultimately, 31 shoulders remained in the PCHLR group for 2-year analysis. The effectiveness of these interventions was assessed using a variety of parameters. Pain scores, ROM, and the Oxford Shoulder Score (OSS) were evaluated before the procedure and at one-year and 2-year follow-up visits. RESULTS: In this 2-year follow-up study, a total of 31 shoulders were sampled, comprising 22 women and 5 men, with 4 patients undergoing bilateral procedures. The mean age of the patients was 65 years (± 11.48). Patients' mean body mass index (BMI) was 36.33 (± 6.55), and the mean CHL thickness was 38.5 (± 3.45). Osteoarthritis was present in 11 cases. The mean follow-up period for the study was 29.7 months (± 6.39). The baseline mean external rotation was 30° (± 8), which increased to 62° (± 18) at one year and 53° (± 18) at 2 years. The baseline mean abduction was 60° (± 16), which improved to 77° (± 21) at one year and 68° (± 20) at 2 years. The median NRS decreased from 8 (IQR: 8, 9) at baseline to 3 (IQR: 2, 7) at one year and 5 (IQR: 2, 7) at 2 years. The baseline median OSS was 7 (IQR: 3, 10), which increased to 32 at one year and 22 (IQR: 15, 35) at 2 years. LIMITATIONS: The present investigation has a limited sample size of patients who have ROM impairment caused by CHL thickening. CONCLUSIONS: While the algorithm for AC care has seen little change for several decades, the authors suggest that PCHLR is a safe, durable, and effective option for cases of AC that are refractory to traditional management.

Trainee Insight into Pain Fellowship Programs: A Critical Evaluation of the Current Educational System by the APPD.

BACKGROUND: Since 1992, when the Accreditation Council of Graduate Medical Education (ACGME) acknowledged pain medicine as a subspecialty, the field has experienced significant growth in its number of programs, diversity of sponsoring specialties, treatment algorithms, and popularity among applicants. These shifts prompted changes to the educational model, overseen by program directors (PDs) and the ACGME. The pool of pain fellowship applicants also changed during that period. OBJECTIVES: This study aims to investigate trainees' reasons for applying to pain medicine fellowship programs as well as the applicants' specific expectations, interests, and motivations, thereby contributing to the remodeling and universal improvement of programs across the country. STUDY DESIGN: Online survey via SurveyMonkey. The online questionnaire targeted pain fellowship applicants in 2023 and current fellows in the US. METHODS: Our study was designed by board members of the Association of Pain Program Directors (APPD). The board disseminated a survey to those who applied to ACGME Pain Medicine fellowships in 2023 as well as to existing fellows. The survey was emailed to residency and fellowship PDs for dissemination to their trainees. The participants answered a 12-question survey on their reasons for pursuing pain medicine fellowships, expectations of and beyond those fellowships, and educational adjustments. RESULTS: There were 283 survey participants (80% applicants in residency training and 20% fellows). Participants ranked basic interventional procedures and a strong desire to learn advanced procedures as the most significant factors in pursuing a pain fellowship. Most trainees (70%) did not wish to pursue a 2-year fellowship, and 50% desired to go into private practice. LIMITATIONS: The relatively small number of respondents is a limitation that could introduce sampling error. Since most of the respondents were from the fields of physical medicine and rehabilitation (PM&R) and anesthesia, the use of convenience sampling reduced our ability to generalize the results to the wider community. Furthermore, approximately 80% of the trainees were residents, who might have had less experience in or knowledge of the survey's particulars than did the fellows. CONCLUSION: This survey demonstrated that procedural volume and diversity were important factors in trainees' decisions to apply to the field of pain medicine; however, extending the duration of a pain fellowship was not an option survey participants favored. Therefore, PDs and educational stakeholders in pain fellowship training need to develop creative strategies to maintain competitive applicants' interest while they adapt to our evolving field.

Predicting the Collapse of Pain Medicine Using the Economic Recession of 2008 as a Comparator: Lessons Remain Unlearned.

The last decade has seen a boom in pain medicine, basic science and interventional pain management. Concomitantly, there is a need to educate trainees, young attendings, and seasoned attendings on these innovations. There has been a growth in the number of societies that represent pain medicine physicians, each with its own philosophy and guiding principles. The variety of thought within pain management, within the various groups that practice this field, and amongst the societies which protect those missions inherently creates divergence and isolation within these different communities. There is the enormous opportunity for our field to grow, but we need the voices of all different specialties and sub-specialties which practice pain medicine to collectively design the future of our emerging field. The explosion of revolutionary percutaneous surgeries, medications, psychotherapy, and research and development in our field has outpaced the ability of payers to fully embrace them. There is an increased number of pain practitioners using novel therapies, postgraduate training programs do not adequately train users in these techniques thereby creating a potential for sub-optimal outcomes. In part, this is a reason why payers for many of our more novel treatments have decreased patient access or eliminated remuneration for some of them. We believe that society-based collaborative regulation of education, research, and treatment guidelines is needed to improve visibility for payers and end users who provide these treatments. Furthermore, postgraduate chronic pain fellowship education has been deemed by many to be insufficient to educate on all of the necessary requirements needed for the independent practice of pain medicine, especially the consummation of newer technologies. Here, we draw comparison with this tenuous stage in pain management history with the last United States recession to remind us of how poor institutional regulation and neglect for long-term growth hampers a community.

Is Chronic Tendon Pain Caused by Neuropathy? Exciting Breakthroughs may Direct Potential Treatment.

BACKGROUND: Tendinopathy significantly impacts the quality of life and imposes a high economic burden, accounting for a large proportion of sports and musculoskeletal injuries. Traditionally considered a collagen-related inflammatory disorder, emerging evidence suggests a critical role of neuropathic processes in chronic tendon pain. OBJECTIVE: This review aims to evaluate the neuropathic mechanisms in tendinopathy and discuss innovative treatments targeting these pathways. METHODS: We analyze recent studies highlighting the tendon innervation, pathological nerve sprouting neuronal ingrowth in tendinopathy, and the associated increase in pain and neuronal mediators. RESULTS: Chronic tendinopathy exhibits nociceptive sprouting from paratenon into the fibrous tendon proper. Innovative treatments such as Percutaneous Ultrasound-Guided Tenotomy (PUT) or high-frequency ultrasound interventions show promise in targeting these neuropathic components by paratenon separation. These approaches focus on disrupting the pathological innervation cycle. CONCLUSION: Chronic tendon pain may be predominantly neuropathic, driven by pathologic neuronal ingrowth from paratenon into the tendon proper. Interventions that accurately target and disrupt these nerve pathways could revolutionize the treatment of tendinopathy. Further research is required to validate these findings and refine treatment modalities to ensure safety and efficacy.

Radiofrequency ablation of the hip: review.

Radiofrequency ablation (RFA) of the articular branches of the femoral and obturator nerves (the innervation of the anterior capsule of the hip) is an emerging treatment for chronic hip pain. Body mass index (BMI) greater than 30, older age, large acetabular/femoral head bone marrow lesions, chronic widespread pain, depression, and female sex increase the risk of developing hip pain. Chronic hip pain is a common condition with a wide range of etiologies, including hip osteoarthritis (OA), labral tears, osteonecrosis, post total hip arthroplasty (THA), post-operative dislocation/fracture, and cancer. The most common and well studied is hip OA. Management of chronic hip pain includes conservative measures (pharmacotherapy and exercise), surgery, and percutaneous procedures such as RFA. While surgery is effective, those whose medical comorbidities preclude surgery, those who do not wish to have surgery, and those whose pain persists after surgery (11-36% of patients) could benefit from RFA. Because of the aforementioned circumstances, hip RFA is often a palliative intervention. Hip RFA is an effective treatment, one recent retrospective study of 138 patients found 69% had >50% pain relief at 6 months. The most frequent adverse event reported for hip RFA is pain from needle placement. No serious bleeding events have been reported, despite the valid concern of the procedure's proximity to vasculature. This descriptive review details the pathophysiology of hip pain, its etiologies, its clinical presentation, conservative management, the anatomy/technique of hip RFA, hip RFA efficacy, and RFA adverse events.

The current state of training in pain medicine fellowships: An Association of Pain Program Directors (APPD) survey of program directors.

INTRODUCTION: The Accreditation Council for Graduate Medical Education (ACGME) approved the first pain medicine fellowship programs over three decades ago, designed around a pharmacological philosophy. Following that, there has been a rise in the transition of pain medicine education toward a multidisciplinary interventional model based on a tremendous surge of contemporaneous literature in these areas. This trend has created variability in clinical experience and education amongst accredited pain medicine programs with minimal literature evaluating the differences and commonalities in education and experience of different pain medicine fellowships through Program Director (PD) experiences. This study aims to gather insight from pain medicine fellowship program directors across the country to assess clinical and interventional training, providing valuable perspectives on the future of pain medicine education. METHODS: This study involved 56 PDs of ACGME-accredited pain fellowship programs in the United States. The recruitment process included three phases: advanced notification, invitation, and follow-up to maximize response rate. Participants completed a standard online questionnaire, covering various topics such as subcategory fields, online platforms for supplemental education, clinical experience, postgraduate practice success, and training adequacy. RESULTS: Surveys were completed by 39/56 (69%) standing members of the Association of Pain Program Directors (APPD). All PDs allowed fellows to participate in industry-related and professional society-related procedural workshops, with 59% encouraging these workshops. PDs emphasized the importance of integrity, professionalism, and diligence for long-term success. Fifty-four percent of PDs expressed the need for extension of fellowship training to avoid supplemental education by industry or pain/spine societies. CONCLUSION: This study highlights the challenge of providing adequate training in all Pain Medicine subtopics within a 12-month pain medicine fellowship. PDs suggest the need for additional training for fellows and discuss the importance of curriculum standardization.

Mitigating Factors in L4 and L5 Medial Branch Motor Stimulation During Radiofrequency Ablation.

PURPOSE OF REVIEW: Radiofrequency ablation (RFA) is a minimally invasive procedure for facet joint pain. The targets for the procedure are the medial branches of the dorsal spinal nerves which innervate the facet joints. Before RFA, patients undergo diagnostic meal branch blocks to ensure appropriate pain relief and confirm the utility of proceeding to RFA. The success of RFA relies heavily on procedural technique and accurate placement near the medial branch. RECENT FINDINGS: Motor testing is utilized in the lumbar region to assess the response of the multifidus and ensure proper placement of the RFA probe to prevent inadvertent damage to surrounding spinal anatomy. However, relying on motor responses in this area presents challenges given the frequency of lack of muscle twitching. Factors contributing to limited muscle twitch responses include muscle atrophy, excessive lordosis, facet arthropathy, local anesthetic use before ablation, and previous surgical neurotomy. These complexities highlight the challenges in ensuring precise motor stimulation during RFA. Despite these obstacles, accurate anatomical placement remains crucial. For RFA cases that prove challenging, relying on anatomical placement can be adequate to proceed with the procedure. Bridging knowledge gaps is vital for standardized practices and safer procedures. Further research is necessary to refine techniques, understand patient-specific factors, and enhance the efficacy of RFA in managing chronic lumbar facet joint pain.

Current Waveforms in Spinal Cord Stimulation and Their Impact on the Future of Neuromodulation: A Scoping Review.

BACKGROUND: Neuromodulation is a standard and well-accepted treatment for chronic refractory neuropathic pain. There has been progressive innovation in the field over the last decade, particularly in areas of spinal cord stimulation (SCS) and dorsal root ganglion stimulation. Improved outcomes using proprietary waveforms have become customary in the field, leading to an unprecedented expansion of these products and a plethora of options for the management of pain. Although advances in waveform technology have improved our fundamental understanding of neuromodulation, a scoping review describing new energy platforms and their associated clinical effects and outcomes is needed. The authors submit that understanding electrophysiological neuromodulation may be important for clinical decision-making and programming selection for personalized patient care. OBJECTIVE: This review aims to characterize ways differences in mechanism of action and clinical outcomes of current spinal neuromodulation products may affect contemporary clinical decision-making while outlining a possible path for the future SCS. STUDY DESIGN: The study is a scoping review of the literature about newer generation SCS waveforms. MATERIALS AND METHODS: A literature report was performed on PubMed and chapters to include articles on spine neuromodulation mechanism of action and efficacy. RESULTS: A total of 8469 studies were identified, 75 of which were included for the scoping review after keywords defining recent waveform technology were added. CONCLUSIONS: Clinical data suggest that neuromodulation remains a promising tool in the treatment of chronic pain. The evidence for SCS for treating chronic pain seems compelling; however, more long-term and comparative data are needed for a comparison of waveforms when it comes to the etiology of pain. In addition, an exploration into combination waveform therapy and waveform cycling may be paramount for future clinical studies and the development of new technologies.

Adipose Tissue Impacts Radiofrequency Ablation Lesion Size: Results of an Ex Vivo Poultry Model.

BACKGROUND: Radiofrequency ablation (RFA) is a common treatment in which radiofrequency (RF) is used to heat neural tissue and reduce pain. The impact of adipose content in tissue on the lesion size may impact efficacy, and to date, there is little, if any, data comparing its influence on RFA. OBJECTIVES: We evaluated the influence of adipose tissue on RF lesion size. STUDY DESIGN: Controlled, ex vivo study. SETTING: Academic institution in a procedural setting. METHODS: RF lesions were created using 20-G 10-mm protruding electrode (PE) needles inserted into unbrined chicken breasts and thighs at 21°C. RF current was applied for 90 seconds at 80°C. Chicken breasts were used as the control group and chicken thighs were used as the high adipose variant. Four different groups were examined: 1- Standard 20 g RFA needle, 2- 20 g RFA PE needle, 3- Standard RFA needle with lidocaine 2% injectate, and 4- Standard RFA needle with iohexol 240 mg injectate. There were 12 lesions performed in each group; length, width, and depth were measured. RESULTS: The control group had significantly deeper lesions in all 4 cohorts. Lesions' lengths were smaller in the fat-rich group. The control and PE cohorts showed a significant difference in width between the 2 fat-rich and nonfatty groups. LIMITATIONS: Radiofrequency ablation was performed at room temperature and not heated to physiological temperature. This was an ex vivo study, thus factors of human anatomy and physiology could not be evaluated. CONCLUSIONS: Adipose tissue content was inversely related to lesion size in all samples. This factor should be considered when assessing methods of enhancing lesion size in human models.

Percutaneous Ultrasound-Guided Coracohumeral Ligament Release for Refractory Adhesive Capsulitis: A Prospective, Randomized, Controlled, Crossover Trial Demonstrating One-Year Efficacy.

BACKGROUND: Adhesive capsulitis (AC) is a painful and disabling condition with restricted range of motion (ROM) that affects 2% to 3% of the population and up to 20% of patients with diabetes. AC can be idiopathic, iatrogenic, or secondary to shoulder injuries. Some associated conditions include diabetes mellitus, thyroid disorders, dyslipidemia, stroke, prolonged immobilization, and autoimmune conditions. Management ranges from analgesics to physical therapy, local injections, hydrodilatation, and advanced surgical interventions. This study examines percutaneous coracohumeral ligament (PCHL) sectioning with the hypothesis that interruption would improve pain and ROM in patients with AC refractory to conservative management. OBJECTIVES: To use sonographically guided percutaneous interruption of the CHL for the treatment of refractory AC. STUDY DESIGN: A prospective, randomized, controlled, cross-over trial. SETTING: Academic medical center. METHODS: Patients were identified based on inclusion and exclusion criteria under the supervision of the Principal Investigator. After primary screening, research staff explained the study, risks, and benefits to the patients, and consent was obtained. Patients' pain score and shoulder ROM were assessed before and after the procedure, at one month, and one year. The Oxford Shoulder Scoring (OSS) questionnaire was also completed before the procedure and in the one-year follow-up visit.Forty patients were enrolled with refractory AC. Forty-six shoulders were treated; 6 patients underwent a bilateral procedure. Block 2:1 randomization was performed for the 2 groups (PCHL release [PCHLR] and local anesthetic CHL [LACHL]). The LACHL group received a lidocaine injection at CHL, and the PCHLR group received the CHL using a Tenex® (Tenex Health, Lake Forest, CA) needle. ROM, Numeric Rating Scale (NRS-11), and OSS were evaluated at baseline, immediate postprocedure, and long term. RESULTS: Among 46 shoulders included in the study, 7 were excluded due to lost to follow-up, total shoulder replacement, and shoulder manipulation. Twenty-six were randomized to the PCHLR group and 13 to LACHL group. ROM (external rotation and abduction), pain, NRS-11 score, and OSS score were measured at baseline and long term, confirmed by a nonbiased health care personnel. There was no statistically significant difference in ROM, NRS-11, and OSS between the 2 cohorts at the baseline visit. Nine patients in LACHL group crossed over to the PCHLR arm at one month. Data analysis in the long term revealed durability of the PCHLR group with a statistically significant difference in ROM, NRS-11, and OSS. External rotation improved by double, and abduction improved by almost 30% (P value < .001). NRS-11 decreased from 8 (IQR 8, 9) at baseline to 3 (IQR 2, 7) at long term among those who received PCHLR. The baseline mean OSS in the PCHLR group increased from 7.44 to 31.86 at one-year follow-up and was statistically significant (P value < .001). LIMITATIONS: This study represents a small population of patients with a CHL-related ROM deficit. Patients were not excluded for osteoarthritis or other motion-disabling shoulder conditions. We submit that the strength of the study could have been improved if the physician performing the procedure was blinded and if the patient was blinded as well to minimize operator and patient bias. CONCLUSIONS: We demonstrate that our technique for PCHLR is a safe, effective, and durable procedure that improved ROM, pain, and shoulder function in our patient population when compared to the control. KEY WORDS: Tenex, frozen shoulder, pain, range of motion, function, shoulder, minimally invasive, durable.

Percutaneous Ultrasound-Guided Tenotomy of the Iliotibial Band for Trochanteric Pain Syndrome: A Longitudinal Observational Study With One-Year Durability Results.

BACKGROUND: Upper lateral hip pain is a common complaint in adults and is referred to as greater trochanteric pain syndrome (GTPS) and is more prevalent among older women. This is a debilitating condition that could result in lower physical activity and quality of life, and higher unemployment rate. GTPS is a clinical diagnosis, and many cases improve with conservative medical management (CMM). However, there is still a gap between patients not responding to CMM and those who are not good surgical candidates. Thus, percutaneous ultrasound tenotomy (PUT) may be a valuable treatment option to limit this gap. OBJECTIVES: Demonstration of the one-year pain and functional outcomes, including sit to stand. SETTING: Academic tertiary care medical center. METHODS: Forty-eight consecutive patients with refractory trochanteric pain due to iliotibial band (ITB) tendinopathy. Fifty-six hips were treated; 8 patients underwent bilateral procedures. Electronic medical record review of consecutive patients who underwent ITB TENEX® was performed at Montefiore Medical Center from December 2019 to December 2021. Institutional guidelines recommended TENEX® for greater trochanteric pain refractory to conservative treatment and ultrasound (US) confirmed ITB tendinopathy (hypoechogenicity or thickened tendon > 6 mm). Pain level, as well as sit-to-stand, side-lying, and walking tolerance levels were evaluated at baseline preprocedure visit and one-year visit. Follow-up was performed by independent practitioners and corroborated by chart review. RESULTS: Numeric Rating Scale (NRS-11) improved by 4 points across all patients. Seventy percent of patients endorsed pain relief at one-year visit. Median preprocedure NRS-11 was 9. The reported median NRS-11at one year was 5 (Wilcoxon signed rank NRS-11 demonstrated a Z score of -6.042 with P < 0.001). One-year analysis among all patients revealed 57%, 78%, and 66% improvement in side-lying, sit-to-stand, and walking tolerance levels, respectively. LIMITATIONS: We believe that our results must be confirmed with a randomized control trial with a control arm and more patients included. CONCLUSIONS: PUT of the ITB using the TENEX® tissue remodeling device could be a safe and effective treatment for ITB tendinopathy-associated GTPS.

Treatment of Refractory Low Back Pain Using Passive Recharge Burst in Patients Without Options for Corrective Surgery: Findings and Results From the DISTINCT Study, a Prospective Randomized Multicenter Controlled Trial.

OBJECTIVE: Spinal cord stimulation (SCS) is effective for relieving chronic intractable pain conditions. The Dorsal spInal cord STImulatioN vs mediCal management for the Treatment of low back pain study evaluates the effectiveness of SCS compared with conventional medical management (CMM) in the treatment of chronic low back pain in patients who had not undergone and were not candidates for lumbar spine surgery. METHODS AND MATERIALS: Patients were randomized to passive recharge burst therapy (n = 162) or CMM (n = 107). They reported severe pain and disability for more than a decade and had failed a multitude of therapies. Common diagnoses included degenerative disc disease, spondylosis, stenosis, and scoliosis-yet not to a degree amenable to surgery. The six-month primary end point compared responder rates, defined by a 50% reduction in pain. Hierarchical analyses of seven secondary end points were performed in the following order: composite responder rate (numerical rating scale [NRS] or Oswestry Disability Index [ODI]), NRS, ODI, Pain Catastrophizing Scale responder rate, Patient Global Impression of Change (PGIC) responder rate, and Patient-Reported Outcome Measure Information System-29 in pain interference and physical function. RESULTS: Intention-to-treat analysis showed a significant difference in pain responders on NRS between SCS (72.6%) and CMM (7.1%) arms (p < 0.0001). Of note, 85.2% of those who received six months of therapy responded on NRS compared with 6.2% of those with CMM (p < 0.0001). All secondary end points indicated the superiority of burst therapy over CMM. A composite measure on function or pain relief showed 91% of subjects with SCS improved, compared with 16% of subjects with CMM. A substantial improvement of 30 points was observed on ODI compared with a

The Effect of Local Anesthetics and Contrast Agents on Radiofrequency Ablation Lesion Size.

BACKGROUND: Radiofrequency ablation (RFA) is a validated treatment option for the treatment of chronic pain in patients with lumbar spondylosis. Lesion size has been suggested to correlate with good clinical outcomes. This has created an abundance of scientific interest in the development of products with larger lesion characteristics. Needle characteristics, energy transfer, and heat rate are known to modify lesion size. Here, we demonstrate that common intraoperative solutions, such as lidocaine, iodine, and gadolinium-based products, can also affect lesion shape. OBJECTIVES: To determine whether lidocaine and contrast agents modify lesion characteristics during the performance of monopolar RFA. STUDY DESIGN: Controlled, ex vivo study using clinically relevant conditions and pre-injections. SETTING: Academic institution in a procedural setting. METHODS: RFA lesion size was compared among six cohorts: 1) lidocaine 1%, 2) lidocaine 2%, 3) iohexol 180, 4) iohexol 240, 5) gadodiamide, and 6) control (no fluid control). Radiofrequency (RF) current was applied for 90 seconds at 80°C via 20-gauge 100-mm standard RFA needles with 10-mm active tips in orgranic chicken breasts without preservative at room temperature (21°C). Twelve lesions were performed for each medication cohort. The length, width, and depth of each lesion were measured. The statistical significance between each medication group and the control group was evaluated by t test. RESULTS: The mean lesion surface area of monopolar RFA without any pre-injection used was 80.8 mm2. The mean surface area of the monopolar RF lesion with a pre-injection of 0.2 mL of 2% lidocaine was 114 mm2, and the mean surface area of the monopolar RF lesion with a pre-injection of 0.2 mL of iohexol 240 was 130.6 mm2. The statistical analysis demonstrated that the control group had significantly smaller lesion sizes than did the groups in which lidocaine 2% and iohexol 240 were used (P<0.01). There were no statistically significant differences among the groups in which lidocaine 1%, iohexol 180, and gadodiamide were used. A notable difference was a 20% longer lesion with iohexol 240 compared with the control group and a 20% wider lesion with lidocaine 2% compared with the control group. LIMITATIONS: In vivo anatomy within a human was not used in this study, nor were the chicken breasts heated to physiological temperature. Randomization of pieces of chicken breast did not occur, and thus intrinsic differences among the chicken breast pieces could play a confounding role. CONCLUSIONS: Lidocaine 2% and iohexol 240, when used as pre-injections in RFAs, were found to be associated with statistically significant increases in lesion surface area. However, RFAs with lidocaine 1%, iohexol 180, or gadodiamide were not found to produce a statistically significant difference in lesion size compared with monopolar RFA without the use of injectate.

Contrast Spread After Erector Spinae Plane Block at the Fourth Lumbar Vertebrae: A Cadaveric Study.

INTRODUCTION: In recent years, the erector spinae plane block (ESPB) has seen widespread use to treat acute and chronic pain in the regions of the thoracic spine. While limited data suggest its increasing utilization for pain management distal to the thoracic, abdomen and trunk, the anesthetic spread and analgesic mechanism of ESPB at the level of the lumbar spine has not been fully described or understood. METHODS: This is an observational anatomic cadaveric study to assess the distribution of solution following an ESPB block performed at the fourth lumbar vertebrae (L4) using ultrasound guidance to evaluate the spread of a 20 ml solution consisting of local anesthetic and methylene blue. The study was performed in an anatomy lab in a large academic medical center. Following injection of local anesthetic with contrast dye, cadaveric dissection was performed to better understand the extent of contrast dye and to determine the degree of staining to further predict analgesic potential. We reviewed the findings of other ESPB cadaveric studies currently available for comparison. RESULTS: Following cadaveric dissection in an anatomy lab, the contrast dye was observed in the ESP space, and staining was found most cranially at L2 and extending caudally underneath the sacrum. Evaluating the depth of its spread, we found it to be confined to the posterior compartment of the spine sparing the nerve roots bilaterally, which is consistent with the only other cadaveric study of ESPB performed at L4. CONCLUSION: Our results demonstrate the clinical utility of lumbar ESPB where posterior confinement of local anesthesia is preferred. However, further investigation is needed to determine the efficacy of ESPB in lower extremity analgesia which is predicated on ventral nerve root involvement.

Cervical Facet Joint Pain and Cervicogenic Headache Treated With Radiofrequency Ablation: A Systematic Review.

BACKGROUND: Chronic neck pain is often multifactorial and is a leading cause of pain and disability. Cervical facet joint pain is a common cause of neck pain and, in addition to more conservative modalities, can be treated with radiofrequency ablation (RFA) of the respective medial branch nerves. Cervicogenic headaches are a frequent complaint in pain clinics in the United States and can be targeted via a similar procedural approach. OBJECTIVES: We evaluated randomized controlled trials of cervical facet joint pain and cervicogenic headaches with the goal of establishing a current level of evidence for treating these etiologies of pain with RFA. STUDY DESIGN: Systematic review. METHODS: Database search, from inception through July 2021, was performed identifying randomized controlled trials for cervical medial branch RFA. Two reviewers independently evaluated the studies to identify those meeting criteria. Primary outcome measures included pain relief and duration of pain relief. Secondary outcome measures included function, sleep, mood, return to work, additional treatments, and complications. RESULTS: Four randomized controlled studies met inclusion criteria and were selected for this review, each demonstrated low risk of bias. Of these studies, 3 were unique with the fourth being a subgroup analysis. Primary outcome measures of pain relief and duration of relief were variable with successful relief ranging from 30% to 50% and median duration of pain relief also demonstrating a wide variety. Function and psychological distress were also variably reported and found variable relief to treatment with no difference between groups in 2 of the studies. LIMITATIONS: Primary limitations of the review are the paucity of randomized controlled trials and the variability in measured outcome measures. CONCLUSIONS: Based on this systematic review, efficacy of cervical facet RFA in treatment of chronic neck pain has Level II evidence.