Implantable Subdural Cortical Stimulation for Chronic Intractable Pain Treatment-The Mayo Experience and Review of Literature.

OBJECTIVES: Motor cortex stimulation (MCS) is an effective technique in treating chronic intractable pain for some patients. However, most studies are small case series (n < 20). Heterogeneity in technique and patient selection makes it difficult to draw consistent conclusions. In this study, we present one of the largest case series of subdural MCS. MATERIALS AND METHODS: Medical records of patients who underwent MCS at our institute between 2007 and 2020 were reviewed. Studies with at least 15 patients were summarized for comparison. RESULTS: The study included 46 patients. Mean age was 56.2 ± 12.5 years (SD). Mean follow-up was 57.2 ± 41.9 months. Male-to-female ratio was 13:33. Of the 46 patients, 29 had neuropathic pain in trigeminal nerve territory/anesthesia dolorosa; nine had postsurgical/posttraumatic pain; three had phantom limb pain; two had postherpetic pain, and the rest had pain secondary to stroke, chronic regional pain syndrome, and tumor. The baseline numeric rating pain scale (NRS) was 8.2 ± 1.8 of 10, and the latest follow-up score was 3.5 ± 2.9 (mean improvement of 57.3%). Responders comprised 67% (31/46)(NRS ≥ 40% improvement). Analysis showed no correlation between percentage of improvement and age (p = 0.352) but favored male patients (75.3% vs 48.7%, p = 0.006). Seizures occurred in 47.8% of patients (22/46) at some point but were all self-limiting, with no lasting sequelae. Other complications included subdural/epidural hematoma requiring evacuation (3/46), infection (5/46), and cerebrospinal fluid leak (1/46). These complications resolved with no long-term sequelae after further interventions. CONCLUSION: Our study further supports the use of MCS as an effective treatment modality for several chronic intractable pain conditions and provides a benchmark to the current literature.

A Case Report of Multimodal Analgesia for the Treatment of Refractory Chronic Nipple Pain.

Chronic nipple pain can be challenging to a multidisciplinary care team. We report a case of a patient who experienced years of ineffective treatment before presenting to the pain management clinic. Upon presentation, the patient was trialed on neuropathic agents, topical pain medications, acupuncture, calcium channel blockers, intercostal nerve blocks, pulsed radiofrequency, and a spinal cord stimulator trial. We report the treatment options and what was ultimately effective to improve pain scores and functionality. Presenting this treatment approach will educate the reader about options for multimodal therapy to avoid delayed treatment for other patients in the future.

Bicentre, randomized, parallel-arm, sham-controlled trial of transcranial direct-current stimulation (tDCS) in the treatment of palliative care patients with refractory cancer pain.

BACKGROUND: Pain is a common symptom in palliative care cancer patients and is often insufficiently relieved. In recent years, transcranial direct-current stimulation (tDCS) of the motor cortex has been shown to be effective to treat chronic pain, essentially neuropathic pain. We propose to test the efficacy of tDCS in patients experiencing cancer pain in the palliative care setting. METHOD/DESIGN: This article describes the protocol of a bicentre, randomized, parallel-arm, sham-controlled clinical trial evaluating tDCS in the treatment of palliative care patients with refractory cancer pain. Seventy patients between the ages of 18 and 80 years experiencing refractory pain with a pain score of 4/10 on a numerical rating scale (NRS) ranging from 0 to 10 will be enrolled in this trial. The main exclusion criteria are patients unable to fill in the various rating scales and life expectancy less than 3 weeks. Treatment consists of 5 consecutive tDCS sessions targeting the motor cortex (one daily session for 5 days) on the contralateral side to the pain. After randomization (1:1 ratio), 35 patients will receive active stimulation and 35 patients will receive sham stimulation. The primary endpoint is the NRS score and the primary objective is a significant improvement of this score between the baseline score recorded between D-3 and D-1 and the score recorded 4 days after stopping treatment (D8). The secondary objectives are to evaluate whether this improvement is maintained 16 days after stopping treatment (D21) and whether the following scores are improved on D14 and D21: Brief Pain Inventory, Edmonton Symptom Assessment System, Hospital Anxiety and Depression scale, State-Trait Anxiety Inventory and Medication Quantification Scale. DISCUSSION: Positive results of this trial would indicate that tDCS can improve pain and quality of life of cancer patients in the palliative care setting. Reduction of analgesic consumption and improvement of activities of daily living should allow many patients to return home with a decreased workload for caregivers.

Functional MRI-Guided Motor Cortex and Deep Brain Stimulation for Intractable Facial Pain: A Novel, Personalized Approach in 1 Patient.

BACKGROUND: Facial neuropathic pain syndromes such as trigeminal neuralgia are debilitating disorders commonly managed by medications, vascular decompression, and/or ablative procedures. In trigeminal neuralgia cases unresponsive to these interventions, trigeminal deafferentation pain syndrome (TDPS) can emerge and remain refractory to any further attempts at these conventional therapies. Deep brain stimulation (DBS) and motor cortex stimulation are 2 neuromodulatory treatments that have demonstrated efficacy in small case series of TDPS yet remain largely underutilized. In addition, functional MRI (fMRI) is a tool that can help localize central processing of evoked stimuli such as mechanically triggered facial pain. In this study, we present a case report and operative technique in a patient with TDPS who underwent fMRI to guide the operative management and placement of dual targets in the sensory thalamus and motor cortex. OBJECTIVE: To evaluate the safety, efficacy, and outcome of a novel surgical approach for TDPS in a single patient. METHODS: The fMRI and operative technique of unilateral DBS targeting the ventroposteromedial nucleus of the thalamus and facial motor cortex stimulator placement through a single burr hole is illustrated as well as the patient's clinical outcome. RESULTS: In less than 1 year, the patient had near complete resolution of his facial pain with no postoperative complications. CONCLUSION: We present the first published case of successful treatment of TDPS using simultaneous DBS of the ventroposteromedial and motor cortex stimulation. fMRI can be used as an effective imaging modality to guide neuromodulation in this complex disorder.

Availability of and factors related to interventional procedures for refractory pain in patients with cancer: a nationwide survey.

BACKGROUND: Cancer pain may be refractory to standard pharmacological treatment. Interventional procedures are important for quality of analgesia. The aim of the present study was to clarify the availability of four interventional procedures (celiac plexus neurolysis/splanchnic nerve neurolysis, phenol saddle block, epidural analgesia, and intrathecal analgesia), the number of procedures performed by specialists, and their associated factors. In addition, we aimed to establish how familiar home hospice physicians and oncologists are with the different interventional procedures available to manage cancer pain. METHODS: A cross-sectional survey using a self-administered questionnaire was conducted. Subjects were certified pain specialists, interventional radiologists, home hospice physicians, and clinical oncologists. RESULTS: The numbers of valid responses/mails were 545/1,112 for pain specialists, 554/1,087 for interventional radiology specialists, 144/308 for home hospice physicians, and 412/800 for oncologists. Among pain specialists, depending on intervention, 40.9-75.2% indicated that they perform each procedure by themselves, and 47.5-79.8% had not performed any of the procedures in the past 3 years. Pain specialists had performed the four procedures 4,591 times in the past 3 years. Among interventional radiology specialists, 18.1% indicated that they conduct celiac plexus neurolysis/splanchnic nerve neurolysis by themselves. Interventional radiology specialists had performed celiac plexus neurolysis/splanchnic nerve neurolysis 202 times in the past 3 years. Multivariate analysis revealed that the number of patients seen for cancer pain and the perceived difficulty in gaining experience correlated with the implementation of procedures among pain specialists. Among home hospice physicians and oncologists, depending on intervention, 3.5-27.1% responded that they were unfamiliar with each procedure. CONCLUSIONS: Although pain specialists responded that the implementation of each intervention was possible, the actual number of the interventions used was limited. As interventional procedures are well known, it is important to take measures to ensure that pain specialists and interventional radiology physicians are sufficiently utilized to manage refractory cancer pain.

[Hypoxemia, pleural and pericardial effusion after splanchnic neurolysis. A case report.] / Hipoxemia, derrame pleural y pericárdico en neurolisis de nervios esplácnicos. Reporte de caso

Introduction: Alcohol neurolysis of splanchnic nerves is a valuable tool for treating visceral intractable pain from the upper abdomen in cancer patients. It is a safe and effective procedure, yet not risk free. It's most common adverse effects are mild and self-limited. Materials: We present a case of a 72-year old woman suffering from pancreatic cancer with intractable pain despite opioid use. Alcohol neurolysis of splanchnic nerves was indicated after hospital admission. Results: After the procedure pain was subdued, yet hypoxemia, pleural and pericardial effusion developed. Frequent causes for these events were ruled out. The patient was discharged 24 hours after with adequate pain control. Conclusions: Hypoxemia, pleural and pericardial effusion after alcohol neurolysis of splanchnic nerves is infrequent. These findings are likely to be linked to the effect of alcohol.

Introducción: La neurolisis o alcoholización de los nervios esplácnicos es una valiosa herramienta para el tratamiento del dolor visceral del abdomen superior de origen neoplásico en pacientes con mala respuesta a tratamiento por vía oral. Es un procedimiento seguro y efectivo, aunque no exento de riesgos. Sus efectos adversos más frecuentes son leves y autolimitados. Materiales: Presentamos el caso de una mujer de 72 años con cáncer de páncreas y mal manejo del dolor pese al consumo de opioides. Se le indico neurolisis de los nervios esplácnicos bajo internación. Resultados: Post procedimiento presentó buen manejo del dolor, sin embargo evolucionó con hipoxemia, derrame pleural bilateral y pericárdico. Se descartaron causas frecuentes de estos eventos. La paciente fue dada de alta a las 24 hs con buen manejo del dolor. Conclusiones: El desarrollo de hipoxemia, derrame pleural bilateral y pericárdico posterior a la neurolisis de los nervios esplácnicos es una complicación infrecuente. Estos hallazgos probablemente se encuentren vinculados al efecto del alcohol.

What's New in Peripheral Nerve Stimulation.

Peripheral nerve stimulation (PNS) is a powerful interventional option for the management of otherwise intractable pain. This technique involves the implantation of electrodes to apply electrical stimulation to named peripheral nerves, thereby alleviating pain in the territory of the target nerves. Recent advancements, largely driven by physician-industry relationships, have transformed the therapy into one that is minimally invasive, safe, evidence-based, and effective. Ongoing research has expanded the indications beyond chronic neuropathic pain in a peripheral nerve distribution. This article provides an overview of recent advances in this field.

PALLIATIVE TREATMENT OF INTRACTABLE CANCER PAIN.

In 10% to 30% cancer-pain cases standard analgesic therapy fails to provide effective pain relief. Interventional techniques, such as peripheral nerve blocks, neuraxial analgesia along with neurolytic blocks may be used for such refractory pain. Peripheral nerve blocks can be used when pain occurs in the territory of one or more peripheral nerves, but rarely as main therapy. Neuraxial analgesia is a valid option for progressive cancer pain, and healthcare possibilities and costs call into question the utility of intrathecal infusion pumps. Neurolysis is the targeted destruction of a nerve or nerve plexus, using chemicals, radiofrequency ablation (RFA), cryoablation, and neurosurgical procedures; however, it rarely completely eliminates pain because patients frequently experience coexisting somatic and neuropathic pain as well. Complex conditions of palliative patients along with limited high-quality randomized controlled trials limit the use of interventional procedures. Even so, some cancer patients benefit from interventional procedures to achieve pain alleviation and consequently improve quality of life.

Ultrasound-guided spinal accessory nerve block for intractable trapezius pain.

Myofascial pain affects about 10% of the United States population, often involves the trapezius muscle, and can be difficult to manage using conventional analgesic medications in the Emergency Department (ED). The use of ultrasound-guided nerve blocks performed by emergency physicians is well-documented, but this is the first report describing the technique and effectiveness of an ultrasound-guided spinal accessory nerve block for acutely treating trapezius myofascial pain in the ED setting. In this case series of three patients with intractable trapezius pain, the ultrasound-guided spinal accessory nerve block proved feasible and offered substantial therapeutic benefit.

Vertebroplasty as a palliative treatment option for intractable pain in pediatric patients with spinal tumors.

Primary and secondary malignant tumors of the spine are relatively uncommon in the pediatric population but are associated with high morbidity and significantly decreased quality of life due to pain. Local management of these tumors is often challenging due to the importance of maintaining vertebral mechanical integrity as well as the spinal growth potential. Typically, surgery and/or radiation therapy have been used in the primary management of these tumors. However, treatment options become more limited when there is relapse or refractory disease, with re-resection or additional radiotherapy often not being viable therapies. Vertebroplasty is a currently underutilized modality that might provide significant pain palliation in cases of relapsed cancer in the spine.

Wireless Subcutaneous Trigeminal Nerve Field Stimulation for Refractory Trigeminal Pain: A Single Center Experience.

INTRODUCTION: Subcutaneous trigeminal nerve field stimulation (sTNFS) is a neuromodulatory treatment for neuropathic trigeminal pain with the ability to reduce the intensity and frequency of pain attacks. However, hardware issues including lead migration, skin erosion, infection, so-called pocket pain at the site of the implanted neurostimulator are reported. Implantable wireless neurostimulation technology promises not only an even less invasive sTNFS treatment and thinner and more flexible electrodes better suited for facial implants, but also provides further advantages such as lack of an implantable neurostimulator and 3T magnetic resonance imaging compatibility. MATERIAL AND METHODS: All patients who had received trial stimulation with a partially implantable sTNFS system were analyzed for ICHD-3 (3rd edition of the International Classification of Headache Disorders) diagnosis, success of trial stimulation, pre- and postoperative pain intensity, frequency of attacks, complications, and side-effects of sTNFS. RESULTS: All patients (N = 3) responded to sTNFS (≥50% pain reduction) during the trial period. According to ICHD-3, N = 2 of the patients were classified with trigeminal neuralgia (TN) with concomitant persistent facial pain and N = 1 patient with multiple sclerosis associated TN. The time of the test period was 44 ± 31.24 days (mean ± SD). The average daily duration of stimulation per patient amounted 2.5 ± 2.2 hours (range 1-5). The pain intensity (defined on a visual analog scale) was reduced by 80% ± 17% (mean ± SD). Reduction or cessation in pain medication was observed in all patients. No surgical complications occurred in the long-term follow-up period of 18.84 ± 6 (mean ± SD) months. CONCLUSION: The partially implantable sTNFS device seems to be safe, effective, and reliable. Compared to conventional devices, the equipment is not limited to the length of trial stimulation. Furthermore, the daily stimulation duration was much shorter compared to previous reports.

A Clinical Review of Slipping Rib Syndrome.

ABSTRACT: Slipping rib syndrome is pain created at the lower, anterior border of the rib cage when performing upper-extremity activities, coughing, laughing, or leaning over. Defects in the costal cartilage of ribs 8 to 10 result in increased movement of the ribs, impinging soft tissue and intercostal nerves. Advancements have been made in the diagnosis of slipping rib syndrome by dynamic ultrasound. Ultrasound can identify abnormalities in the rib and cartilage anatomy, as well as soft tissue swelling. Although the mainstays of treatment continue to be reassurance, nonsteroidal anti-inflammatory drugs, physical therapy, intercostal nerve injections, osteopathic manipulative treatment, surgery for refractory pain, and botulinum toxin injections have been attempted, and there may be a role for prolotherapy in treatment. Surgical techniques are being examined secondary to recurrence of pain following resection. The hooking maneuver and surgery remain important for identification and treatment, respectively.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation for the Treatment of Chronic Intractable Pain Originating From a Lipofibromatous Hamartoma of the Median Nerve.

This case report presents an application of peripheral nerve stimulation to the median nerve to treat a patient with intractable pain due to a lipofibromatous hamartoma of the left upper extremity. Ultra high-frequency ultrasound was used to determine the boundaries of the hamartoma. The patient then underwent an ultrasound-guided implantation of 2 stimulator electrodes distal to the elbow along the median nerve with stimulation coverage achieved at 1.2 and 1.4 mA, respectively. After an uneventful procedure, the pain score immediately decreased from 9 out of 10 to less than 6 on a numeric rating scale. Two weeks after the procedure, the patient reported substantial pain relief, with an average pain level of 5 to 6 out of 10. Twelve months after implantation, the patient maintained significant pain relief, rating her average pain level as a 4 to 6 out of 10. Placement of a percutaneous peripheral nerve stimulator was safe and effective with no adverse events being reported at the 12-month follow-up.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Neuroablative Procedures for Patients With Cancer Pain.

BACKGROUND: Managing cancer pain once it is refractory to conventional treatment continues to challenge caregivers committed to serving those who are suffering from a malignancy. Although neuromodulation has a role in the treatment of cancer pain for some patients, these therapies may not be suitable for all patients. Therefore, neuroablative procedures, which were once a mainstay in treating intractable cancer pain, are again on the rise. This guideline serves as a systematic review of the literature of the outcomes following neuroablative procedures. OBJECTIVE: To establish clinical practice guidelines for the use of neuroablative procedures to treat patients with cancer pain. METHODS: A systematic review of neuroablative procedures used to treat patients with cancer pain from 1980 to April 2019 was performed using the United States National Library of Medicine PubMed database, EMBASE, and Cochrane CENTRAL. After inclusion criteria were established, full text articles that met the inclusion criteria were reviewed by 2 members of the task force and the quality of the evidence was graded. RESULTS: In total, 14 646 relevant abstracts were identified by the literature search, from which 189 met initial screening criteria. After full text review, 58 of the 189 articles were included and subdivided into 4 different clinical scenarios. These include unilateral somatic nociceptive/neuropathic body cancer pain, craniofacial cancer pain, midline subdiaphragmatic visceral cancer pain, and disseminated cancer pain. Class II and III evidence was available for these 4 clinical scenarios. Level III recommendations were developed for the use of neuroablative procedures to treat patients with cancer pain. CONCLUSION: Neuroablative procedures may be an option for treating patients with refractory cancer pain. Serious adverse events were reported in some studies, but were relatively uncommon. Improved imaging, refinements in technique and the availability of new lesioning modalities may minimize the risks of neuroablation even further.The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelines-detail/guidelines-on-neuroablative-procedures-patients-wi.

Programming Parameters and Techniques in Trigeminal Ganglion Stimulation for Intractable Facial Pain.

OBJECTIVES: Atypical facial pain syndromes are challenging disorders to manage and often incur limited benefit with surgery for classical trigeminal neuralgia presentations, such as microvascular decompression or ablative procedures. Neurostimulation of the trigeminal ganglion and peripheral nerves can be effective at treating atypical presentations of trigeminal facial pain affecting the V1-3 dermatomes, and the surgical techniques are well described. The stimulation parameters, however, have thus far received limited description; we therefore sought to describe programming strategies. MATERIALS AND METHODS: We performed a retrospective chart review, examining patients that underwent trigeminal ganglion stimulation (TGS) and nerve branch stimulation for atypical facial pain and trigeminal neuropathic pain, and describe the programming strategies in detail. RESULTS: We describe the use of high-frequency stimulation (1000 Hz), with alteration in pulse width (60-220 msec) and amplitude (0.5-3 V) to achieve effective treatment of refractory trigeminal facial pain. These parameters differ from existing published parameters for trigeminal nerve branch stimulation. We also describe the programming of specific contacts on each lead to target specific aspects of the individual patients' facial pain. CONCLUSIONS: The use of effective programming strategies is critical to the success of neurostimulation surgical treatments; however, the critical details in programming strategies typically receive limited description. We report on the use of several successful programming strategies for TGS, to assist pain providers in successfully applying these surgical techniques in these difficult to manage atypical facial pain syndromes.

Extended pulsed radiofrequency as a part of multimodal pain management in a refractory case of Bernhardt-Roth syndrome.

Bernhardt-Roth syndrome (BRS) is a neurological condition characterised by pain, burning or numbness in anterolateral thigh due to entrapment of the lateral femoral cutaneous nerve (LFCN). The possible aetiologies can be mechanical, iatrogenic, neuropathic or idiopathic. After consent for possible publication, we are discussing a case of pain management in a 38-year-old patient with BRS secondary to diabetes. The coherent history, uncontrolled glycaemic status and reduced nerve conduction velocity for LFCN helped reach the diagnosis. Initial treatment with pharmacotherapy, steroid LFCN block and conventional pulsed radiofrequency (PRF) provided moderate temporary pain relief. Extended PRF over 8 min provided significant analgesia without any complications. Physical therapy, adequate glycaemic control and extended PRF provided complete pain relief and improved function over 6 months of follow-up duration. Hence, a cautious multifaceted approach targeting the basic aetiology with extended PRF helped achieve significant analgesia in our refractory case of BRS.

An evidence-based review of neuromodulation for the treatment and management of refractory angina.

Angina pectoris is defined as substernal chest pain that is typically exacerbated by exertion, stress, or other exposures. There are various methods of treatment for angina. Lifestyle modification and pharmacological management are considered as conservative treatments. If these medications do not result in the resolution of pain, more invasive approaches are an option, like coronary revascularization. Refractory angina (RA) is differentiated from acute or chronic angina based on the persistence of symptoms despite conventional therapies. Overall, the prevalence of RA is estimated to be 5%-15% in patients with coronary artery disease, which can account for up to 1,500,000 current cases and 100,000 new cases in the United States per year. Spinal cord stimulation treatment is a viable option for patients who are suffering from RA pain and are either not candidates for revascularization surgery or are currently not being well managed on more traditional treatments. Many studies show a positive result.

Dorsal root ganglion stimulation for the treatment of severe intractable pain related to obturator nerve entrapment neuropathy: A case report.

A 61-year-old Caucasian female, with severe obturator neuropathy following a left pubic ramus fracture was treated successfully with dorsal root ganglion stimulation (DRGS). Both conservative management and a dual-lead dorsal column spinal cord stimulator did not provide effective long-term results. The dorsal root ganglion (DRG) trial was completed five years following the initial fracture, resulting in 90 % pain relief. A permanent device was implanted and after one year, 90 % pain relief was still sustained. DRGS has applicability in future treatment algorithms for patients with mixed nociceptive and neuropathic groin pain refractory to conservative management.