A brief review of complex regional pain syndrome and current management

Complex regional pain syndrome (CRPS) is a debilitating chronic pain condition that, although exceedingly rare, carries a significant burden for the affected patient population. The complex and ambiguous pathophysiology of this condition further complicates clinical management and therapeutic interventions. Furthermore, being a diagnosis of exclusion requires a diligent workup to ensure an accurate diagnosis and subsequent targeted management. The development of the Budapest diagnostic criteria helped to consolidate existing definitions of CRPS but extensive work remains in identifying the underlying pathways. Currently, two distinct types are identified by the presence (CRPS type 1) or absence (CRPS type 2) of neuronal injury. Current management directed at this disease is broad and growing, ranging from non-invasive modalities such as physical and psychological therapy to more invasive techniques such as dorsal root ganglion stimulation and potentially amputation. Ideal therapeutic interventions are multimodal in nature to address the likely multifactorial pathological development of CRPS. Regardless, a significant need remains for continued studies to elucidate the pathways involved in developing CRPS as well as more robust clinical trials for various treatment modalities.

Narrative review of radiofrequency ablation applications in peripheral nerves

BACKGROUND AND OBJECTIVE

Chronic pain is a pervasive and often-complex condition that can severely detract from an individual's quality of life. When conservative measures of treatment fail, radiofrequency ablation (RFA) has emerged as a potential alternative. This narrative review subsequently explores recent advancements in the use of RFA on peripheral nerves as a means of attenuating chronic pain and providing relief to patients.

METHODS

A comprehensive literature search was conducted on the PubMed database using the keywords "Radiofrequency", "Ablation", "Pain", "Chronic", "Peripheral", and "Nerve". The search focused on articles published between 2018 to 2023 that discussed an application of RFA in a peripheral nerve. In total, 30 articles were selected for inclusion in this review.

KEY CONTENT AND FINDINGS

Results indicate the successful use of RFA in an array of chronic pain conditions and anatomical sites. Applications include the treatment of trigeminal neuralgia (TN), occipital neuralgia, cluster headaches, knee pain derived from osteoarthritis (OA), hip pain, abdominal pain associated with pancreatic cancer, and several other chronic pain conditions.

CONCLUSIONS

These findings suggest RFA is a viable option for reducing patient's pain scores and improving quality of life. Future research should build off extensive case reports/series with double-blind, randomized controlled studies to further investigate anecdotal successes.

Spinal Cord Stimulation Waveforms for the Treatment of Chronic Pain

PURPOSE OF REVIEW

Since the advent of spinal cord stimulation (SCS), advances in technology have allowed for improvement and treatment of various conditions, especially chronic pain. Additionally, as the system has developed, the ability to provide different stimulation waveforms for patients to treat different conditions has improved. The purpose and objective of the paper is to discuss basics of waveforms and present the most up-to-date literature and research studies on the different types of waveforms that currently exist. During our literature search, we came across over sixty articles that discuss the various waveforms we intend to evaluate.

RECENT FINDINGS

There are several publications on several waveforms used in clinical practice, but to our knowledge, this is the only educational document teaching on waveforms which provides essential knowledge. There is a gap of knowledge related to understanding wave forms and how they work.

Virtual Reality in Acute and Chronic Pain Medicine: An Updated Review

PURPOSE OF REVIEW

This review critically analyzes the recent literature on virtual reality's (VR) use in acute and chronic pain management, offering insights into its efficacy, applications, and limitations.

RECENT FINDINGS

Recent studies, including meta-analyses and randomized controlled trials, have demonstrated VR's effectiveness in reducing pain intensity in various acute pain scenarios, such as procedural/acute pain and in chronic pain conditions. The role of factors such as immersion and presence in enhancing VR's efficacy has been emphasized. Further benefits have been identified in the use of VR for assessment as well as symptom gathering through conversational avatars. However, studies are limited, and strong conclusions will require further investigation. VR is emerging as a promising non-pharmacological intervention in pain management for acute and chronic pain. However, its long-term efficacy, particularly in chronic pain management, remains an area requiring further research. Key findings highlight that VR programs vary in efficacy depending on the specificity of the origin of pain.

Sacroiliac Joint Denervation-A Novel Approach to Target Sacral Lateral Branches: A Practical Approach

INTRODUCTION

Sacroiliac joint (SIJ) pain is a relatively common cause of low back pain. Percutaneous radiofrequency (RF) techniques for SIJ are limited to ablation of the posterior SIJ innervation. Different techniques have been described for SIJ radiofrequency ablation, including conventional thermal, cooled RF, pulsed RF, bipolar RF, and specialized tip RF needle (i.e., multi-tined); however, additional costs may limit these applications.

METHODS

This new technique for SIJ denervation uses anatomical landmarks and a single RF cannula. Two spinal needles are placed lateral to the posterior S1 and S2 sacral foramina; then, with caudal tilt we get a coaxial view of the sacral bone, we advance an 18-G curved 15-mm active tip RF cannula just lateral to the aligned finder needles. Ablation is performed, and then the RF cannula is retracted 2 cm and ablation is repeated for a total of four lesions.

RESULTS

The two spinal needles placed lateral to the posterior sacral foramina S1 and S2 guide the final needle in the posterior aspect of the sacrum, lateral to the sacral foramina, where the lateral sacral branches are located.

CONCLUSION

We introduce a cost and time efficient technique to perform radiofrequency ablation of the sacral lateral branches using a single RF needle. This technique utilizes the sacrum's reliable anatomy and angulation and maximizes the surface area of the active tip lesioning. This technique creates a strip lesion lateral to the sacral foramina and reduces time and cost efficacy compared to several of the other techniques and/or commercially available special devices designed for sacroiliac denervation.

Infrapatellar Branch of the Saphenous Nerve: Therapeutic Approaches to Chronic Knee Pain

PURPOSE OF REVIEW

The infrapatellar branch of the saphenous nerve (IPS) is an under-investigated nerve that can be a source of chronic knee pain. This literature review aims to deliver an up-to-date review of chronic pain transmitted via the IPS along with therapeutic approaches available for pain refractory to conservative measures.

RECENT FINDINGS

Knee pain transmitted via the IPS can arise from several etiologies. Damage to the IPS is often iatrogenic and develops following total knee arthroplasty, anterior cruciate ligament reconstruction, and other knee surgical procedures. Other causes of IPS-derived pain include entrapment of the nerve, neuromas, Schwannomas, and pain from knee osteoarthritis transmitted through the IPS.This article investigated therapeutic approaches to pain derived from the IPS. Common approaches included radiofrequency ablation, neuroma excisions, Schwannoma excision, nerve blocks, surgical exploration, surgical release of an entrapped nerve, cryoablation, and peripheral nerve stimulation. Pain scores, duration of pain relief, adverse events, and secondary outcomes were all included in this review. A subset of the patient population experiences chronic pain deriving from the IPS that is refractory to conservative treatment measures. This review aims to evaluate the etiologies and therapeutic approaches for chronic pain arising from the IPS refractory to conservative treatments.

Applications of Artificial Intelligence in Pain Medicine

PURPOSE OF REVIEW

This review explores the current applications of artificial intelligence (AI) in the field of pain medicine with a focus on machine learning.

RECENT FINDINGS

Utilizing a literature search conducted through the PubMed database, several current trends were identified, including the use of AI as a tool for diagnostics, predicting pain progression, predicting treatment response, and performance of therapy and pain management. Results of these studies show promise for the improvement of patient outcomes. Current gaps in the research and subsequent directions for future study involve AI in optimizing and improving nerve stimulation and more thoroughly predicting patients' responses to treatment.

The Gut Microbiota and Chronic Pain

PURPOSE OF REVIEW

To examine the effects and interactions between gut microbia and chronic pain.

RECENT FINDINGS

The gut microbiome has been an area of interest in both the scientific and general audience due to a growing body of evidence suggesting its influence in a variety of health and disease states. Communication between the central nervous system (CNS) and gut microbiome is said to be bidirectional, in what is referred to as the gut-brain axis. Chronic pain is a prevalent costly personal and public health burden and so, there is a vested interest in devising safe and efficacious treatments. Numerous studies, many of which are animal studies, have been conducted to examine the gut microbiome's role in the pathophysiology of chronic pain states, such as neuropathy, inflammation, visceral pain, etc. As the understanding of this relationship grows, so does the potential for therapeutic targeting of the gut microbiome in chronic pain.

Neuromodulation's Role in Functional Restoration in Paraplegic and Quadriplegic Patients

Neuromodulation is an alternative, minimally invasive treatment option that, at times, is used as a last resort for chronic pain conditions that are often refractory to other treatment modalities. Moreover, it offers promising prospects for individuals grappling with the formidable challenges posed by paraplegia and quadriplegia resulting from spinal cord injuries. This review article provides a comprehensive assessment of current treatment modalities specifically tailored for paraplegic and quadriplegic patients. We aim to evaluate the existing surgical and non-surgical interventions while delving into the role of neuromodulation in the restoration of function for individuals afflicted with these debilitating conditions. Additionally, we review the efficacy, limitations, and comparative outcomes of diverse treatment strategies available for the management of paraplegia and quadriplegia. Emphasizing the critical need for effective interventions beyond the initial 24 h surgical window, we elucidate the challenges associated with conventional therapies and their limited success in achieving comprehensive functional restoration. Central to this review is an in-depth exploration of neuromodulation's transformative potential in ameliorating the deficits caused by spinal cord injuries. With a particular focus on spinal cord stimulation (SCS), we analyze and compare the outcomes of neuromodulation modalities and traditional treatment regimens, shedding light on the promising strides made in fostering sensory perception, motor function, and patient satisfaction.

Mechanisms of Action of Dorsal Root Ganglion Stimulation

The dorsal root ganglion (DRG) serves as a pivotal site for managing chronic pain through dorsal root ganglion stimulation (DRG-S). In recent years, the DRG-S has emerged as an attractive modality in the armamentarium of neuromodulation therapy due to its accessibility and efficacy in alleviating chronic pain refractory to conventional treatments. Despite its therapeutic advantages, the precise mechanisms underlying DRG-S-induced analgesia remain elusive, attributed in part to the diverse sensory neuron population within the DRG and its modulation of both peripheral and central sensory processing pathways. Emerging evidence suggests that DRG-S may alleviate pain by several mechanisms, including the reduction of nociceptive signals at the T-junction of sensory neurons, modulation of pain gating pathways within the dorsal horn, and regulation of neuronal excitability within the DRG itself. However, elucidating the full extent of DRG-S mechanisms necessitates further exploration, particularly regarding its supraspinal effects and its interactions with cognitive and affective networks. Understanding these mechanisms is crucial for optimizing neurostimulation technologies and improving clinical outcomes of DRG-S for chronic pain management. This review provides a comprehensive overview of the DRG anatomy, mechanisms of action of the DRG-S, and its significance in neuromodulation therapy for chronic pain.

Literature Review: Mechanism, Indications, and Clinical Efficacy of Peripheral Nerve Stimulators in Lower Extremity Pain

PURPOSE OF REVIEW

Lower extremity pain is deemed by Center for Disease Control and Prevention (CDC) to be a significant source of chronic pain in adults. If not appropriately managed, patients are subjected to risks of prolonged musculoskeletal dysfunction, disruption to quality of life, and elevated healthcare expenditures. Peripheral nerve stimulation (PNS) has shown great potential in recent years demonstrating efficacy in multiple diagnoses ranging from acute post-surgical pain to complex regional pain syndrome (CRPS). This study seeks to delineate efficacy of peripheral neuromodulation in the context of chronic lower extremity pain.

RECENT FINDINGS

Prevailing clinical studies demonstrate evidence levels ranging from II to V (Oxford Centre of Level of Evidence) in lower limb PNS, attaining positive outcomes in pain scores, opioid use, and quality of life measures. Nerves most frequently targeted are the sciatic and femoral nerves with post-amputation pain and CRPS most commonly investigated for efficacy. PNS is a promising therapeutic modality demonstrated to be effective for a variety of nociceptive and neuropathic pain conditions in the lower extremity. PNS offers chronic pain physicians a powerful tool in the multi-modal management of lower limb chronic pain.

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.

Peripheral Nerve Stimulation for the Treatment of Superior Cluneal Neuralgia: A Cadaver Demonstration of a Novel Technique for Lead Placement

Superior cluneal neuralgia (SCN) is a distinct cause of lower back and/or leg pain related to pathology of the superior cluneal nerve. When assessing a patient with low back pain (LBP), superior cluneal neuralgia is frequently misdiagnosed. The pathophysiology of SCN ranges from myofascial compression brought on by aberrant muscle tone to direct iatrogenic injury or trauma. In this technical report we will discuss the anatomy of superior cluneal nerve, superior cluneal neuralgia, current treatment modalities, and a novel approach to peripheral nerve stimulation (PNS) lead placement via a cadaver demonstration for SCN.

Novel Implantation Technique for Thoracoabdominal Peripheral Nerve Stimulation via a Transversus Abdominal Plane Approach for Treatment of Chronic Abdominal Pain

Background

Chronic abdominal pain (CAP) is a common and challenging to treat condition with a global prevalence of up to 25%. Despite extensive evaluation, approximately 40% of patients with CAP have an unknown diagnosis. Medications may be ineffective, and surgery is rarely indicated. Interventional treatment including sympathetic blocks, sympathetic neurolysis, and transversus abdominal plane (TAP) blocks may be an option, but their efficacy can wane over time. Neuromodulation has emerged as an option for these patients, as there is evidence of success with dorsal column spinal cord and dorsal root ganglion (DRG) stimulation. Peripheral nerve stimulation (PNS) may be an alternative option, particularly in higher risk patients or in patients for whom neuraxial access may be unsafe or too technically challenging. Thoracoabdominal nerve peripheral nerve stimulation via a TAP approach may be more specifically targeted in comparison to dorsal column or DRG stimulation. In this short report, we detail a technique that the authors have successfully used for thoracoabdominal nerve PNS via a TAP approach for management of CAP.

Methods

This article describes a novel medial to lateral ultrasound guided thoracoabdominal nerve PNS via a TAP approach technique for lead placement and implantation.

Results

A medial to lateral ultrasound guided TAP approach as described to successfully implant percutaneous thoracoabdominal nerve PNS leads for management of CAP.

Conclusion

The thoracoabdominal nerve PNS via a TAP approach lead placement technique noted in this report has been used as a means for management of CAP utilizing peripheral neuromodulation. Here, we present a short report detailing a potential technique for PNS utilization for management of CAP. Further studies are needed to validate the safety and efficacy of this therapy modality, although the authors have found it to be a viable management option for patients with medically refractory neuropathic CAP.

Pudendal nerve blockade for persistent genital arousal disorder (PGAD): A clinical review and case report

BACKGROUND

Persistent genital arousal disorder (PGAD) is a condition characterized by unwanted and potentially painful genital sensations or spontaneous orgasms without stimulation. We present a case of a 55-year-old woman with refractory genital arousal disorder that was treated with serial pudendal nerve blocks.

CASE

RW is a 55-year-old woman with chronic pelvic pain, pudendal neuralgia, MDD, SI, GAD, CRPS, and persistent genital arousal disorder for 11 years. Her PGAD was refractory to conservative management, physical therapy, and bilateral clitoral artery embolization. We performed bilateral pudendal nerve blocks with Kenalog and Bupivacaine, which provided almost complete relief for 2-3 months. We performed a bilateral pudendal nerve radiofrequency ablation; however, there was minimal benefit. RW continues to have significant relief with serial pudendal nerve blocks.

SUMMARY AND CONCLUSION

Persistent genital arousal disorder is often refractory to medication and physical therapy requiring significant intervention such as entrapment surgery or artery embolization. Our case demonstrates pudendal nerve blocks as a potential treatment modality with minimal side effects.

A Guide for Physicians Serving as an Expert Witness for Personal Injury Cases and Other Litigations

PURPOSE OF REVIEW

To provide a guide for physicians serving as an expert witness in all kinds of cases.

RECENT FINDINGS

Different societies proposed different guidelines for physicians serving as an expert witness. We wanted to summarize all recommendations in our article to provide a comprehensive guide to all physicians from different specialties. There is some overlap in recommendations, and it is important for physicians from different specialties to be aware of all recommendations proposed. It is very important for any health care provider who serves as an expert witness for personal injury or other cases to understand the guidelines around this process and best practices.

The Role of Orthoses in Chronic Axial Spinal Conditions

PURPOSE OF REVIEW

Bracing represents a prevalent conservative, non-surgical approach used in the management of chronic spinal conditions such as spondylosis, degenerative disc disease, and spondylolisthesis. A wide variety of orthoses are available to aid in addressing cervical, thoracic, lumbar, thoracic, and SI joint pain. In this review, we aim to comprehensively examine brace types with their current applications and implications of usage.

RECENT FINDINGS

There are multiple cervical bracing options, such as soft and rigid collars, to assist in managing acute trauma and chronic degenerative conditions. The review highlights the nuanced decision-making process between hard and soft collars based on the severity of bone or ligamentous injury and neurological findings. Orthoses for low back pain are commonly used. The review highlights the challenges of chronic neck and lower back pain, emphasizing the importance of clinicians exploring all treatment strategies including braces which can improve function and reduce pain.

Cervical Spinal Cord Stimulation for Failed Neck Surgery Syndrome

PURPOSE OF REVIEW

Cervical spine pain with or without radicular symptoms is a common condition leading to high utilization of the healthcare system with over 10 million medical visits per year. Many patients undergo surgical interventions and unfortunately are still left with neck and upper extremity pain, sometimes referred to as "Failed Neck Surgery Syndrome." When these options fail, cervical spinal cord stimulation can be a useful tool to decrease pain and suffering as well as reduce prescription medication use.

RECENT FINDINGS

Spinal cord stimulation is a well-established therapy for chronic back and leg pain and is becoming more popular for neck and upper extremity pain. Recent studies have explored cervical spinal cord stimulation with successful outcomes regarding improved pain scores, functional outcomes, and reduction of prescription medication use. Continued research into cervical spinal cord stimulation is essential for maximizing its therapeutic potential for patients with chronic neck and upper extremity pain. This review highlights the importance of cervical spinal cord stimulation as an option for patients with failed neck surgery syndrome.

Neuromodulation Techniques for Headache Management

This narrative review aims to summarize evidence regarding the current utilization and future applications of neuromodulation in patients with headaches, with special attention paid to migraine and chronic cluster headache. A search was conducted in PubMed in August of 2023 to survey the current literature on neuromodulation for the treatment of headache. In total, the search yielded 1989 results, which were further filtered to include only systematic reviews published between 2022 to 2023 to capture the most up-to-date and comprehensive research on this topic. The citation lists of these articles were reviewed to find additional research on neuromodulation and supplement the results presented in this paper with primary literature. Research on the use of neuromodulation for the treatment of headache has predominantly focused on four neuromodulation techniques: peripheral nerve stimulation (PNS), transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and spinal cord stimulation (SCS). Outcome measures reported in this article include impact on migraine and headache frequency and/or pain intensity, adverse effects of the neuromodulation technique, and associated costs, when available. We found that neuromodulation has developed utility as an alternative treatment for both chronic cluster headaches and migraines, with a reduction in frequency and intensity of headache most elucidated from the articles mentioned in this review.

Novel ultrasound-guided supraclavicular stellate ganglion block

INTRODUCTION

Stellate ganglion block (SGB) provides diagnostic and therapeutic benefits in pain syndromes in the head, neck, and upper extremity, including complex regional pain syndrome Types I and II, Raynaud's disease, hyperhidrosis, arterial embolism in the region of the arm.

METHODS

We present a novel ultrasound-guided supraclavicular stellate ganglion block. Considering the existing anatomical structures of the targeted area.

RESULTS AND CONCLUSIONS

We hope that we can provide fewer complications and additional benefits with this new approach.

Dorsal root ganglion stimulation (DRG-s) for potential resolution of restless leg syndrome symptoms and increased cost savings for patients: A case study

INTRODUCTION

We report successful use of dorsal root ganglion stimulation (DRG-s) to treat a patient with persistent symptoms of restless leg syndrome (RLS).

METHODS

The treatment involved the placement of a small device millimeters away from the patient's DRG, which are nerves near the spinal cord that carry sensory information from the periphery of the body to the brain. The device automatically delivers electrical impulse to the DRG to alter and decrease pain perception in the brain.

RESULTS

Our case report elucidates the use of this procedure as a targeted therapy for RLS, with a nearly 90% reduction in reported symptoms in our patient, thus potentially reducing morbidity associated with this condition. Furthermore, we report a 10-year cost savings of nearly $90,000 following DRG-s for our patient.

CONCLUSION

This case study aims to demonstrate the effectiveness of DRG-s neuromodulation in managing RLS, a condition that is often difficult and costly to treat.