Faculty Bibliography

BACKGROUND/UNASSIGNED:Chronic knee pain from osteoarthritis (OA) affects a significant proportion of adults over 40. Total knee arthroplasty (TKA) remains the standard for advanced OA, yet up to 20% of patients experience chronic postsurgical pain (CPSP). Genicular nerve radiofrequency ablation (GNRFA) can alleviate pain in those unresponsive to conservative treatments or TKA. However, anatomical variability of the genicular nerves may limit treatment durability. This retrospective, single-center observational study investigated whether using a novel V-shaped active tip needle-which creates larger lesions-could improve outcomes. METHODS/UNASSIGNED:Fifty patients with symptomatic knee OA or CPSP, who had a ≥50% reduction in pain after diagnostic genicular nerve blocks, underwent GNRFA with a V-shaped active tip needle between September 2020 and January 2022. Pain and function were assessed using the visual analogue scale (VAS) at rest and during movement, Western Ontario and McMaster Universities Arthritis Index (WOMAC), Douleur Neuropathique en 4 Questions (DN4), and EuroQol-5 Dimensions (EQ-5D) at baseline and 1, 3, 6, and 9 months post-procedure. RESULTS/UNASSIGNED:By 6 months, 64% of patients showed ≥50% reduction in VAS pain scores, sustained at 9 months (p<0.0001). Median WOMAC scores improved from 62.0 at baseline to 40.0 at 6 months (p<0.0001). DN4 scores declined from a median of 4.0 at baseline to 2.0 at 6 months and 1.0 at 9 months (p<0.001). EQ-5D scores demonstrated significant enhancement in quality of life (p<0.01). Pain intensity differences at rest and during movement remained substantially improved at 9 months (p<0.0001). CONCLUSION/UNASSIGNED:GNRFA using a V-shaped active tip needle is a promising intervention for chronic knee pain, offering significant and sustained pain relief and functional improvement. Larger lesions created by the novel needle may overcome anatomical challenges, though further randomized studies are warranted to validate efficacy and safety.

INTRODUCTION/UNASSIGNED:Ideally, a physical or chemical nonsurgical neurolytic procedure provides targeted neurolysis to relieve pain for a suitable length of time without causing complications. This narrative review focuses on five nonsurgical neurolytic procedures that are well-established and well-documented in the literature for the treatment of refractory neuropathic pain and peripheral neuropathies, in particular: two physical nonsurgical neurolytic techniques (cryoablation and radiofrequency ablation) and three chemoneurolytic agents (alcohol injection, phenol injection, and a high-concentration capsaicin 8% topical system). METHODS/UNASSIGNED:Using the definition of nonsurgical physical and chemical neurolytic procedures for neuropathic pain, a focused literature search of the PubMed database for English-language, human studies published through July 2024 included, but was not limited to, the following search terms: "neuropathic pain" AND "cryoablation", "cryoneurolysis", "radiofrequency ablation", "alcohol neurolysis", "alcohol injection", "phenol neurolysis", "phenol injection", "chemoneurolysis", "topical capsaicin", and "TRPV1." While attempts were made to identify prospective clinical trials for each type of neurolytic procedure, information regarding the conduct and safety and efficacy of some of these nonsurgical neurolytic procedures was primarily limited to case studies and anecdotal evidence. RESULTS/UNASSIGNED:The risk benefit basis of each technique is discussed, and recommendations for proper use based on the literature are summarized. Most techniques require ultrasound or fluoroscopy guidance. Pain relief typically ranges from 3 to 12 months, with repeat neurolytic procedures often required to maintain suitable levels of pain relief. CONCLUSION/UNASSIGNED:The authors provide their insights as to the best utilization of these identified nonsurgical physical and chemoneurolytic procedures for the treatment of refractory neuropathic pain in different patient populations based on neural targets. Together, these five nonsurgical neurolytic techniques provide patients and physicians with a variety of options for the treatment of refractory neuropathic pain.

Infections related to neuromodulation devices such as spinal cord stimulators (SCS) and intrathecal pumps (ITPs) present complex challenges due to potential complications such as localized infections, deep infections, sepsis, and neurological injury. Prompt diagnosis requires patients and providers to be educated on wound management and sepsis symptoms for immediate medical attention. Antibiotic therapy and duration vary based on infection severity, with deep infections often requiring device removal despite recent improvements in salvage rates with aggressive initial intervention. Deep infections necessitate timely diagnosis through imaging modalities such as magnetic resonance imaging (MRI) or computed tomography (CT), followed by device removal and culture-guided antibiotic therapy, often in collaboration with infectious disease specialists and spine surgeons. ITP infections pose similar challenges along with the risk of meningitis and may require careful management of medication withdrawal symptoms during emergent pump removal. Lab monitoring may aid treatment assessment, although negative cultures can occur due to post-antibiotic exposure. Postoperative recommendations stress standardized guidelines, patient education, and vigilant surveillance, with close follow-up crucial for early infection detection and intervention. Managing device-related infections demands a multi-specialty approach to minimize complications and optimize outcomes. This paper outlines best practices for diagnosing, managing, and treating neuromodulation device infections, focusing on guiding clinical decision-making from the onset of infection through treatment and potential reimplantation.

BACKGROUND/UNASSIGNED:Chronic pain affects 20.5% of the US population, costing $296 billion annually in lost productivity. Spinal cord stimulation (SCS) has become a key treatment for refractory neuropathic and nociceptive pain, with increasing usage due to technological advancements. However, the durability of SCS therapy, including explantation rates, remains a concern. Understanding explantation causes is essential for improving patient selection and device effectiveness. This study aims to analyze SCS explantation rates and reasons, as well as evaluate the financial burden of these procedures on the healthcare system. METHODS/UNASSIGNED:Three primary screening methods were used: manual search with keywords, MeSH term query, and reference list screening. The search covered PubMed, Cochrane, and Web of Science databases from inception to November 2024, yielding 719 articles. After applying eligibility criteria, 72 articles were identified, and 25 were selected for analysis. Data extraction was done by independent reviewers, with a second reviewer ensuring accuracy. Discrepancies were resolved by the corresponding editor. RESULTS/UNASSIGNED:We reviewed data from 13,026 patients who underwent permanent SCS implantation between 1984 and 2024, across 25 studies. A total of 1882 patients (9.82%) underwent explantation. The most common reason was lack of efficacy and inadequate pain relief (38%), followed by lead failure (15%) and infection (14%). While SCS is generally effective, issues related to device longevity and patient satisfaction persist, with explantation rates due to technical failures and lack of efficacy being concerns. CONCLUSION/UNASSIGNED:SCS efficacy varies, with explantation rates reaching up to 38%, often due to inadequate pain relief. Most explantations occur within the first year, despite SCS being a safe and effective treatment. High implantation costs ($35,000 to $70,000) and revision costs ($15,000 to $25,000) raise concerns among payors. The hardware-driven model limits waveform flexibility, highlighting the need for innovation.

INTRODUCTION/UNASSIGNED:The use of electrical neuromodulation has often been limited to those with previous back surgery, peripheral neuropathy, and complex regional pain syndrome. Many patients with severe intractable low back pain were thought to be candidates for spinal cord stimulation (SCS), dorsal root ganglion stimulation, or peripheral nerve stimulation but did not meet the criteria. Recently, additional high-level data has supported the use of SCS in non-surgical low back pain (NSLBP), and United States Food and Drug Administration approval has been granted. The American Society of Pain and Neuroscience (ASPN) executive committee realized an unmet need to develop criteria for patient selection for this specific patient population. This is a NEURON project (neuroscience, education, utilization, risk mitigation, optimal outcomes, and neuromodulation), a living guideline for evolving therapies and indications, and is focused on the use of neuraxial stimulation for the treatment of refractory pain. METHODS/UNASSIGNED:After board approval, the society accepted nominees for the project, with an emphasis on experience, publication, research, and diversity. The team created an outline for discussion, chose a grading system based on published guidelines, and created consensus points. RESULTS/UNASSIGNED:The evidence led to several consensus points to best guide patient selection based on the level of evidence and expert opinion. The results will lead to improved safety and efficacy in implanted patients, and to a new standard for best practices. CONCLUSION/UNASSIGNED:The selection of patients for implantation in those who have NSLBP should be based on published literature, best practice, and expert opinion. This NEURON project will allow for regular updates to create a living guideline that will allow for better assimilation of information to improve safety and efficacy going forward.