Spinal Cord Stimulation as Alternative Treatment for Chronic Post‐Herniorrhaphy Pain

Objective: Our goal was to determine the efficacy of spinal cord stimulation for patients with intractable post‐herniorrhaphy pain which conventional treatment failed to ameliorate. Procedure: The patients underwent an uneventful spinal cord stimulator (SCS) trial with percutaneous placement of two eight‐electrode epidural leads (Medtronic Inc, Minneapolis, MN, USA) to level T7‐T8‐T9. Results: Upon experiencing excellent pain relief over the next two days during the trial, the patients were implanted with permanent leads and rechargeable or non‐rechargeable generators two to four weeks later and reported sustained pain relief during following 12 months after implantation. Conclusion: We conclude that SCS offers an alternative treatment option for intractable post‐herniorrhaphy pain. This type of treatment should be considered for use in a select group of patients when all conventional treatments failed.     

Treatment of Multifocal Pain with Spinal Cord Stimulation

Introduction: We report a retrospective case study of combined treatment of cancer‐related pain and chronic low back and lower extremity pain related to postlaminectomy syndrome (PLS) with one spinal cord stimulation (SCS) system. Methods: The patient underwent an uneventful SCS trial with percutaneous placement of two temporary eight‐electrode leads (Medtronic Inc., Minneapolis, MN) placed at the level of T8‐T9‐T10 and T5‐T6‐T7. Results: After successful trial, he was implanted with permanent leads and generator, reporting sustained pain relief at 12‐month follow‐up visit. Discussion: SCS is a trialable, reversible, and interactive therapy permitting patients to control the level of stimulation they feel based on their degree of pain. Conclusion: SCS provides an effective, alternative treatment for select patients with cancer‐related chest wall pain and pain related to PLS who have failed conservative treatment.     

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

IntroductionSubcutaneous 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 MethodsAll 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.ResultsAll 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.ConclusionThe 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.     

Peripheral Subcutaneous Neurostimulation in the Management of Neuropathic Pain: Five Case Reports

Introduction. Spinal cord stimulation (SCS) is an effective treatment option for neuropathic pain. However, because of the obvious procedural issues, SCS is unable to reach certain areas, such as the face, thorax, coccyx, the cervico‐dorsal and lumbar areas, and the sacral, abdominal, and inguinal regions. On the other hand, these areas are easily reached by subcutaneous field stimulation. Methodology. We report the analgesic results, using a visual analog scale (VAS), of five patients with neuropathic pain treated with subcutaneous field stimulation to the area. We also discuss the probable mechanism of action, and highlight the technical issues inherent to this approach. Results. Significant pain reduction and reduction in analgesic medication were reported in all patients during the study period, with VAS scores consistently lowered by more than 50% from baseline levels. As a result of pain reduction, the patients’ quality of life improved. There were no adverse events reported except for early electrode array displacement in two of our patients. Conclusion. When SCS is not appropriate for certain neuropathic pain syndromes, subcutaneous field stimulation may be used with some degree of efficacy.     

Spinal Cord Stimulation (SCS) in Conjunction With Peripheral Nerve Field Stimulation (PNfS) for the Treatment of Complex Pain in Failed Back Surgery Syndrome (FBSS)

Background: Failed back surgery syndrome (FBSS) is a well‐defined pathologic condition observed over many years. Design: We have investigated the effect of spinal cord stimulation (SCS) with peripheral nerve field stimulation (PNfS) in eight patients with FBSS Outcome Measure: The following parameters were collected and analyzed: The pain intensity score on a 0–10 numbering rating scale (NRS), the psychologic profile with Beck Depression Inventory (BDI), the pain quality with McGill Pain Questionnaire—short form (MGPQ‐sf), the back pain with Oswestry scale score (OS), and the health general quality pattern with QualityMetric's SF‐36v2^® Health Survey. Patients: Eight patients with low back and radicular pain in FBSS are reported. The mean duration of pain was 6.7 months, and the mean NRS score was 9.5, BDI 28.8, MGPQ‐sf 16.8, OS 44.5, and SF‐36 score was 72.8. The average drug intake of opioids was 250 mg/day. Intervention: In six patients, two octopolar leads were placed in epidural space at D7‐D8 and D8‐D9, in conjunction with two octopolar leads placed in lumbar‐sacral subcutaneous space (Precision System, Boston Scientific, Valencia, CA, USA), and in two patients, a two tetrapolar leads was placed in epidural space at D8‐D9 with two tetrapolar leads (Pisces Quad, Plus, Medtronic Inc., Minneapolis, MN, USA) placed in lumbar‐sacral subcutaneous space (Restore Ultra, Medtronic Inc., Minneapolis, MN, USA). Results: After one year mean of follow‐up, the mean NRS score was 4, BDI 8, MGPQ‐sf 5, OS 21, and the SF‐36 score was increased at 108.5. The mean drug intake of opioids was decreased at 20 mg/day. Conclusion: The combination of SCS and PNfS, using the latest rechargeable systems, may be a valid therapeutic strategy in FBSS.     

Spinal Cord Stimulation and Thalamic Pain: Long‐term Results of Eight Cases

Objectives. We submit a retrospective analysis of results of eight patients suffering from intractable pain of established or suspected thalamic origin. These patients were treated with spinal cord stimulation (SCS) in the cervical or dorsal cord. No patient was suffering pain from a complete hemibody or facial area. Material and Methods. Five men and three women aged 27–67 years were treated in the Pain Unit of our institution between April 1993 and January 2006. The cause of pain in five cases was stroke (plus one suspected). Multiple sclerosis was responsible for pain in two cases. An upper or lower extremity was affected in six cases. Extension to adjacent trunk was common. Exclusive trunk pain was treated in two cases. Results. The follow‐up period was 36–149 months. Two patients were not battery‐implanted because pain relief was insufficient during the trial phase. Two patients had a further stroke: One died and one was cured from pain. Good‐to‐excellent results were attained in six patients; long‐term good‐to‐excellent results were maintained in three patients. Conclusions. Despite previous adverse reports, certain cases of thalamic pain can be effectively alleviated through SCS.     

A Retrospective Comparison of Long-Term Treatment Results of Subcutaneous Stimulation and Spinal Cord Stimulation for Chronic Neuralgia

ObjectivesSpinal cord stimulation (SCS) is known to be an effective long-term treatment option for chronic neuropathic pain. Subcutaneous stimulation (SubQ) is increasingly used to treat chronic back and neck pain, but long-term outcomes are unclear.Materials and MethodsPatients with neurostimulation devices implanted during the past 16 years were evaluated. Their continuation or termination of the treatment was taken as a measure of long-term treatment success. Age, sex, underlying pain condition, stimulation modality (SCS, SubQ, or hybrid), occurrence, and reasons for treatment termination were documented. Patients were classified as long-term responders and long-term nonresponders and analyzed with their clinical data and stimulation modality. The sample consisted of 98 patients. Of these, 66 were treated with SCS, 21 with SubQ, and 11 with a hybrid system.ResultsApproximately 61.3% of patients receiving SubQ terminated the treatment within two years because of ineffectiveness, whereas only 28.8% of patients receiving SCS terminated their stimulation. Back and neck pain were associated with treatment termination (p = 0.011). SubQ was also significantly associated with treatment termination.ConclusionsSubQ seems not to provide substantial long-term pain relief for back and neck pain because most patients abandoned their stimulation therapy.     

Motor Cortex Stimulation for Pain: A Narrative Review of Indications,Techniques, and Outcomes

BackgroundMotor cortex stimulation (MCS) was introduced in 1985 and has been tested extensively for different types of peripheral and central neuropathic pain syndromes (eg, central poststroke pain, phantom limb pain, trigeminal neuropathic pain, migraines, etc). The motor cortex can be stimulated through different routes, including subdural, epidural, and transcranial.ObjectivesIn this review, we discuss the current uses, surgical techniques, localization techniques, stimulation parameters, and clinical outcomes of patients who underwent chronic MCS for treatment-resistant pain syndromes.Materials and MethodsA broad literature search was conducted through PubMed to include all articles focusing on MCS for pain relief (keywords: subdural, epidural, repetitive transcranial magnetic stimulation, transcranial direct current stimulation, motor cortex stimulation, pain).Literature ReviewEpidural MCS was the most widely used technique and had varying response rates across studies. Long-term efficacy was limited, and pain relief tended to decrease over time. Subdural MCS using similar stimulation parameters demonstrated similar efficacy to epidural stimulation and less invasive methods, such as repetitive transcranial magnetic stimulation (rTMS), which have been shown to provide adequate pain relief. rTMS and certain medications (ketamine and morphine) have been shown to predict the long-term response to epidural MCS. Complications tend to be rare, the most reported being seizures during subdural or epidural stimulation or hardware infection.ConclusionsScientific evidence supports the use of MCS for treatment of refractory neuropathic pain syndromes. Further studies are warranted to elucidate the specific indications and stimulation protocols that are most amenable to the different types of MCS.     

Long-Term Outcome of Spinal Cord Stimulation for Chronic Pain Management

Study Design. This is a retrospective study on 102 patients subjected to implantation of a spinal cord stimulation system for nonmalignant chronic pain management. The study was conducted through an extensive questionnaire and telephone interviews by a neutral third party. All the patients were implanted with a complete spinal cord stimulation system without a preliminary trial with a temporarily implanted electrode. Diagnostic categories were neuropathic pain, failed back syndrome, spinal cord Injury pain, and miscellaneous. Average follow-up was 3.8 years (6 months to 8 years). Patients were divided in two groups: all the implanted patients in the survey (Group A) and the implanted patients who experienced some degree of pain relief with the stimulation (Group B). Group B (80 patients) closely matches previously published series where an initial temporary screening was performed. Results. Twenty-one percent of the patients never experienced any pain relief. Of the remaining 80, 75% were still using the stimulator. Fifty-one percent of the 80 patients were experiencing good to excellent results and 20% moderate results. There was no reduction over time in the amount of pain relief in patients who initially had at least 75% pain relief. Patients with initial pain relief between 50% and 74% observed a moderate reduction in their pain relief after two years. Patients who initially experienced less than 50% pain relief observed a dramatic reduction in their results in the long term follow-up. Psychological screening contributed to the success of the procedure. Conclusions. With proper medical and psychological screening and with demonstrated initial pain relief, spinal cord stimulation remains an effective modality in the long-term management of severe chronic pain.     

Role of the Anterior Cingulate Cortex in Translational Pain Research

As the most common symptomatic reason to seek medical consultation,pain is a complex experience that has been classified into different categories and stages.In pain processing,noxious stimuli may activate the anterior cingulate cortex(ACC).But the function of ACC in the different pain conditions is not well discussed.In this review,we elaborate the commonalities and differences from accumulated evidence by a variety of pain assays for physiological pain and pathological pain including inflammatory pain,neuropathic pain,and cancer pain in the ACC,and discuss the cellular receptors and signaling molecules from animal studies.We further summarize the ACC as a new central neuromodulation target for invasive and non-invasive stimulation techniques in clinical pain management.The comprehensive understanding of pain processing in the ACC may lead to bridging the gap in translational research between basic and clinical studies and to develop new therapies.     

Neuromodulation With Burst and Tonic Stimulation Decreases Opioid Consumption: A Post Hoc Analysis of the Success Using Neuromodulation With BURST (SUNBURST) Randomized Controlled Trial

ObjectivesThe SUNBURST study was a prospective, multicenter, randomized crossover trial of a single device delivering burst and tonic spinal cord stimulation (SCS) for chronic trunk and/or limb pain. We performed a post hoc analysis of opioid consumption at baseline and after device implantation.Materials and MethodsAfter implantation, 100 patients were randomized to one mode (tonic or burst) for 12 weeks, and the other mode for the subsequent 12 weeks. After the crossover period (24 weeks), patients chose their preferred mode and were assessed for one year. We analyzed 69 patients who took opioid medication at baseline. The primary endpoint was opioid consumption in morphine milligram equivalents (MMEs) at baseline and 12 months postimplantation. Subgroup analysis included opioid consumption based on Center for Disease Control markers (<50, 50–90, 90–120, >120 MME/day) and stimulation mode preference.ResultsOpioid consumption at 12 months was lower compared to baseline (53.94 vs. 79.19 MME, MD −25.25, 95% CI −43.77 to 6.73, p = 0.008). By 12 months, 11 of 69 patients (15.9%) discontinued all opioid (p = 0.001). Based on CDC dose markers, the proportion of patients taking >120 MME/day decreased by 61.7% at 12 months postintervention compared to baseline (p = 0.043). Forty-five of 69 patients (65.2%) preferred burst SCS while 15 of 69 patients (21.7%) preferred tonic SCS (p < 0.001).ConclusionA device delivering tonic and burst SCS was associated with decreased opioid consumption after 12 months in patients with chronic trunk and/or limb pain. The proportion of patients reporting the highest opioid intake (>120 MME/day) decreased to a lower CDC dose category by 61.7%, carrying important implications for those at highest risk for opioid-related substance use disorder, overdose, and death.     

Treatment of chronic intractable atypical facial pain using peripheral subcutaneous field stimulation

Introduction: Atypical facial pain (ATFP) is challenging to manage and there are few proven therapies available. We present a case report describing application of peripheral subcutaneous field stimulation (PSFS) to a patient with chronic intractable ATFP which conventional treatment failed to ameliorate. Methods: The patient underwent an uneventful PSFS trial with percutaneous placement of two temporary eight‐electrode leads (Medtronic Inc, Minneapolis, MN, USA) placed subdermally over the left mandible. Results: After experiencing excellent pain relief over the next two days, the patient was implanted with permanent leads and rechargeable generator two and a half weeks later and reported sustained pain relief at 12‐month follow‐up visit. Discussion: Peripheral subcutaneous field stimulation provides an effective treatment option for patients suffering from chronic ATFP who have failed conservative treatment. PSFS may provide pain relief with advantages over conservative treatments and more invasive techniques. Conclusion: Peripheral subcutaneous field stimulation offers an alternative treatment option to select patients with intractable ATFP.     

Treatment of Chronic Chest Wall Pain in a Patient With Loeys-Dietz Syndrome Using Spinal Cord Stimulation

Objective: Spinal cord stimulation (SCS) has been used with increased frequency for the treatment of intractable pain including chronic chest pain. Methods: The patient with a history of Loeys‐Dietz syndrome who underwent repair of pectus excavatum with subsequent chronic chest wall pain underwent an uneventful SCS trial with percutaneous epidural placement of two temporary eight‐electrode leads placed at the level of T3‐T4‐T5. Results: After experiencing excellent pain relief over the next two days, the patient was implanted with permanent leads and rechargeable generator four weeks later and reported sustained pain relief at 12‐month follow‐up visit. Conclusion: SCS provides an effective, alternative treatment option for select patients with Loeys‐Dietz syndrome who underwent repair of pectus excavatum with subsequent chronic chest wall pain who have failed conservative treatment. SCS may provide pain relief with advantages over conservative treatments and more invasive techniques.