9. Chronic knee pain.

INTRODUCTION: Chronic knee pain is defined as pain that persists or recurs over 3 months. The most common is degenerative osteoarthritis (OA). This review represents a comprehensive description of the pathology, diagnosis, and treatment of OA of the knee. METHODS: The literature on the diagnosis and treatment of chronic knee pain was retrieved and summarized. A modified Delphi approach was used to formulate recommendations on interventional treatments. RESULTS: Patients with knee OA commonly present with insidious, chronic knee pain that gradually worsens. Pain caused by knee OA is predominantly nociceptive pain, with occasional nociplastic and infrequent neuropathic characteristics occurring in a diseased knee. A standard musculoskeletal and neurological examination is required for the diagnosis of knee OA. Although typical clinical OA findings are sufficient for diagnosis, medical imaging may be performed to improve specificity. The differential diagnosis should exclude other causes of knee pain including bone and joint disorders such as rheumatoid arthritis, spondylo- and other arthropathies, and infections. When conservative treatment fails, intra-articular injections of corticosteroids and radiofrequency (conventional and cooled) of the genicular nerves have been shown to be effective. Hyaluronic acid infiltrations are conditionally recommended. Platelet-rich plasma infiltrations, chemical ablation of genicular nerves, and neurostimulation have, at the moment, not enough evidence and can be considered in a study setting. The decision to perform joint-preserving and joint-replacement options should be made multidisciplinary. CONCLUSIONS: When conservative measures fail to provide satisfactory pain relief, a multidisciplinary approach is recommended including psychological therapy, integrative treatments, and procedural options such as intra-articular injections, radiofrequency ablation, and surgery.

Twelve-month results from a randomized controlled trial comparing differential target multiplexed spinal cord stimulation and conventional spinal cord stimulation in subjects with chronic refractory axial low back pain not eligible for spine surgery.

Background: Successful treatments for intractable chronic low back pain (CLBP) in patients who are not eligible for surgical interventions are scarce. The superior efficacy of differential target multiplexed spinal cord stimulation (DTM SCS) to conventional SCS (Conv-SCS) on the treatment of CLBP in patients with persistent spinal pain syndrome (PSPS) who have failed surgical interventions (PSPS-T2) motivated the evaluation of DTM SCS versus Conv-SCS on PSPS patients who are non-surgical candidates (PSPS-T1). Methods: This is a prospective, open label, crossover, post-market randomized controlled trial in 20 centers across the United States. Eligible patients were randomized to either DTM SCS or Conv-SCS in a 1:1 ratio. Primary endpoint was CLBP responder rate (percentage of subjects with ≥50% CLBP relief) at 3-month in randomized subjects who completed trialing (modified intention-to-treat population). Patients were followed up to 12 months. Secondary endpoints included change of CLBP and leg pain, responder rates, changes in disability, quality of life, patient satisfaction and global impression of change, and safety profile. An optional crossover was available at 6-month to all patients. Results: About 121 PSPS-T1 subjects with CLBP and leg pain mostly associated with degenerative disc disease and radiculopathy and who were not eligible for spine surgery were randomized. CLBP responder rate with DTM SCS (93.5%) was superior to Conv-SCS (36.4%) at the primary endpoint. Superior CLBP responder rates (88.1%-90.5%) were obtained with DTM SCS at all other timepoints. Mean CLBP reduction with DTM SCS (6.52 cm) was superior to that with Conv-SCS (3.01 cm) at the primary endpoint. Similar CLBP reductions (6.23-6.43 cm) were obtained with DTM SCS at other timepoints. DTM SCS provided significantly better leg pain reduction and responder rate, improvement of disability and quality of life, and better patient satisfaction and global impression of change. 90.9% of Conv-SCS subjects who crossed over were CLBP responders at completion of the study. Similar safety profiles were observed between the two groups. Conclusion: DTM SCS for chronic CLBP in nonsurgical candidates is superior to Conv-SCS. Improvements were sustained and provided significant benefits on the management of these patients.

Maximal Analgesic Effect Attained by the Use of Objective Neurophysiological Measurements With Closed-Loop Spinal Cord Stimulation.

OBJECTIVES: Spinal cord stimulation (SCS) has been challenged by the lack of neurophysiologic data to guide therapy optimization. Current SCS programming by trial-and-error results in suboptimal and variable therapeutic effects. A novel system with a physiologic closed-loop feedback mechanism using evoked-compound action potentials enables the optimization of physiologic neural dose by consistently and accurately activating spinal cord fibers. We aimed to identify neurophysiologic dose metrics and their ranges that resulted in clinically meaningful treatment responses. MATERIALS AND METHODS: Subjects from 3 clinical studies (n = 180) with baseline back and leg pain ≥60 mm visual analog scale and physical function in the severe to crippled category were included. Maximal analgesic effect (MAE) was operationally defined as the greatest percent reduction in pain intensity or as the greatest cumulative responder score (minimal clinically important differences [MCIDs]) obtained within the first 3 months of SCS implant. The physiologic metrics that produced the MAE were analyzed. RESULTS: We showed that a neural dose regimen with a high neural dose accuracy of 2.8µV and dose ratio of 1.4 resulted in a profound clinical benefit to chronic pain patients (MAE of 79 ± 1% for pain reduction and 12.5 ± 0.4 MCIDs). No differences were observed for MAE or neurophysiological dose metrics between the trial phase and post-implant MAE visit. CONCLUSION: For the first time, an evidence-based neural dose regimen is available for a neurostimulation intervention as a starting point to enable optimization of clinical benefit, monitoring of adherence, and management of the therapy.

A single-center real-world review of 10 kHz high-frequency spinal cord stimulation outcomes for treatment of chronic pain.

Objective: To compare pragmatic real-world 10-kHz high-frequency spinal cord stimulation (HF-SCS) outcomes at a single academic center to the industry-sponsored SENZA-RCT and Stauss et al. study. Methods: This single-center retrospective study included patients with refractory back or limb pain trialed and/or permanently implanted with the Nevro HF-SCS system from 2016 to 2021. Demographic and outcome data were obtained from the electronic medical record (EMR) and real-world global database maintained by Nevro Corp. Data obtained from the global database were confirmed using the EMR. Main outcome measures included positive responder status (≥50% patient-reported percentage pain reduction (PRPPR)), improvement in function, improvement in sleep, and reduction in pain medication usage. Comparison groups included patient outcomes from the SENZA-RCT and Stauss et al. study. Results: Patients (N = 147) trialed with HF-SCS were reviewed, with data available for 137. Positive trialed patient responder rate (≥50% PRPPR) was 77% (106/137, 95CI 70-84%) vs. 87% (1393/1607, 95CI 85-89%) Stauss et al. vs. 93% (90/97, 95CI 88-98%) SENZA-RCT HF-SCS. At the last available follow-up, positive implanted patient responder rate was 73% (58/80, 95CI 63-82%) vs. 78% (254/326, 95CI 73-82%) Stauss et al. vs. 79% (71/90, 95CI 70-87%) SENZA-RCT HF-SCS. Sixty-seven percent (59/88, 95CI 57-77%) reported improved function vs. 72% (787/1088, 95CI 70-75%) Stauss et al.; 45% (31/69, 95CI 33-57%) reported improved sleep vs. 68% (693/1020, 95CI 65-71%) Stauss et al. and 16% (9/56, 95CI 6-26%) reported decrease in medication use vs. 32% (342/1070, 95CI 29-35%) Stauss et al. Conclusion: Patient responder rates in this retrospective pragmatic real-world study of HF-SCS are consistent with previous industry-sponsored studies. However, improvements in quality-of-life measures and reduction in medication usage were not as robust as reported in industry-sponsored studies. The findings of this non-industry-sponsored, independent study of HF-SCS complement those of previously published studies by reporting patient outcomes collected in the absence of industry sponsorship.

Dorsal root ganglion stimulation for patients with chronic pelvic pain: A retrospective review of patient experiences and long-term outcomes.

Introduction: Chronic pelvic pain (CPP) is a refractory condition that has physical, emotional, and financial impacts on patients. Dorsal root ganglion stimulation (DRGS) is a promising interventional modality for patients with refractory CPP, however studies of long-term outcomes are limited. We aim to present the results from a retrospective review of 31 patients with CPP treated using DRGS. Materials and methods: IRB approval was obtained. A retrospective chart review was conducted, including 31 patients who underwent a DRGS trial between 2017 and 2022 at two academic centers. Pain history, trial/implant lead configuration, complications/revisions, pain scores, functional goals, and medication use were recorded. Results: Thirty-one patients with CPP underwent a 7-10 day DRGS trial between 2017 and 2022. Of the 31 patients, 21 (68%, CI 50-81%) had a successful trial, defined as >50% reported pain relief. Twenty patients underwent DRGS implantation. Average follow-up was 28.2 ± 17.3 months. Nine patients (45%) required revision surgery for lead migration or fracture. Thirteen patients remain implanted with an average reported percent relief of 55 ± 15%. Seven patients were explanted (35%), with an average time to explant of 12.5 ± 3 months. Conclusions: This study presents one of the largest groups of patients with DRGS for the treatment of CPP. The results highlight the variable experiences of patients after DRGS trial/implant. We report on the incidence of lead migration and fracture, sparingly described in the literature. Larger, prospective studies are needed to elucidate which patients with CPP may benefit most from DRGS, and to better understand the incidence and implications of complications.

Socioeconomic Determinants of Initiating Neuromodulation for Chronic Pain: A Systematic Review.

OBJECTIVES: Neuromodulation is an effective treatment for chronic pain; however, socioeconomic differences may influence decision-making to initiate this therapy. This review investigated potential differences in accessibility of neuromodulation for patients with chronic pain due to socioeconomic determinants. MATERIALS AND METHODS: Four electronic databases were used for this systematic review: MEDLINE, Embase, Scopus, and Web of Science. Risk of bias was assessed using the modified version of the Downs and Black checklist. The study protocol was prospectively registered on PROSPERO (CRD42023426035). RESULTS: The initial database search identified a total of 1118 unique studies, of which 36 were eventually included in the systematic review. Of the 36 included studies, six studies reported on education, 24 on employment status, ten on insurance, five on household income, and three on miscellaneous topics. Neuromodulation seems accessible for patients with different education levels and different types of insurance. Additionally, it is not restricted to patients who are (un)employed. When comparing patients who initiated neuromodulation with those who did not, a significantly higher number of patients in the top quartile for education were found in the group without neuromodulation. Regarding insurance, inconclusive evidence was found. CONCLUSIONS: Although neuromodulation was accessible for patients with varying levels of socioeconomic determinants, disparities were noted. When comparing the socioeconomic profiles of patients who receive neuromodulation and those who do not, education levels differ. Health-related inequality should be carefully monitored in chronic pain management with neuromodulation to ensure that potential disparities do not increase.

Low-energy differential target multiplexed SCS derivative reduces pain and improves quality of life through 12 months in patients with chronic back and/or leg pain.

INTRODUCTION: Energy-reducing spinal cord stimulation (SCS) approaches have the potential to impact patient experience with rechargeable and non-rechargeable SCS devices through reducing device recharge time or enhancing device longevity. This prospective, multi-center study evaluated the safety, effectiveness, and actual energy usage of differential target multiplexed (DTM) endurance therapy, a reduced energy DTM SCS derivative. METHODS: Subjects who reported an overall pain visual analog score (VAS) of ≥6/10 cm and an Oswestry Disability Index score of 21-80 out of 100 at baseline with moderate to severe chronic, intractable back and/or leg pain were eligible. Evaluation visits occurred at 1, 3, 6, and 12 months post-device activation. The primary objective was to characterize change in overall pain intensity, as measured by VAS, from baseline to 3-month visit. RESULTS: Fifty-seven subjects enrolled at 12 US sites from November 2020 through June 2021, 35 were implanted with a rechargeable SCS device, and 27 completed the 12-month visit. Subjects experienced a 50.4% mean reduction in overall pain from baseline at the 3-month follow-up that was sustained through 12 months. Additional outcomes including changes in overall, back, and leg pain intensity, quality of life, disability, therapy satisfaction, safety, and current battery usage are shown through 12-month follow-up. CONCLUSION: The use of DTM endurance SCS therapy in this study resulted in reductions in pain relief through 12 months, demonstrating that energy-reducing stimulation patterns can provide clinical benefit. Clinically effective, reduced energy SCS derivatives have the potential to impact patient experience through either reduced recharge requirements or increased device longevity.

The MuscleSCS Technique (4-8Hz BurstDRTM Octrode™): A Randomized Clinical Study of MuscleSCS Stimulation in the Treatment of Chronic Back Pain.

BACKGROUND: MuscleSCS is a new technique that combines spinal cord stimulation (SCS) with muscle stimulation to relieve pain. OBJECTIVES: In this clinical study, we wanted to use rod electrodes to investigate the MuscleSCS method's effectiveness in the treatment of chronic lower back pain. One of our hypotheses was that the combined use of MuscleSCS and BurstDRTM would further improve the treatment. STUDY DESIGN: A prospective, single-center, single-blinded, randomized crossover study. SETTING: A university medical center. METHODS: Patients with chronic lower back pain had previously (one to 10 years ago) received an SCS system (Octrode™). In this study, they were randomly treated for 2 weeks each with BurstDRTM stimulation alone, MuscleSCS stimulation alone, or a combination of BurstDRTM stimulation and MuscleSCS stimulation. Thereafter, the patients were treated for another 6 weeks with one of the 3 methods (crossover possible). Pain ratings on the visual analog scale (VAS) were recorded and compared. A Pain Disability Index (PDI) questionnaire was used at the baseline and at 3 months. RESULTS: We included 24 patients in this study (11 women, mean age 62.3 yrs.) The values of the second week of the stimulation were the only ones used for the calculations. The first week of the stimulation was used as a wash-out period.The combined application of BurstDRTM and MuscleSCS stimulation was associated with the best results (P = 0.032). PDI scores did not improve during this treatment. No serious adverse events occurred during this study. Seventy-one and a half percent of the patients experienced an improvement in their pain as a result of the additional MuscleSCS stimulation. LIMITATIONS: In this study, only one fixed contact setting (3 & 4) was used to ensure uniform conditions for all patients and the ability to compare the different treatment modes. CONCLUSION: This study showed that the combined application of SCS (BurstDRTM) and additional MuscleSCS stimulation using a rod electrode could significantly improve outcomes for patients suffering from chronic back pain.

Percutaneous Endoscope-assisted Visualized Implantation of Puncture Cylindrical Electrodes for Spinal Cord Stimulation: A Cadaveric Feasibility Study.

BACKGROUND: Spinal cord stimulation is an established technique wherein diverse electrode types are strategically implanted within the spinal epidural space for neuromodulation. Traditional percutaneous puncture cylindrical electrodes (PEs) are predominantly implanted by interventionalists utilizing a percutaneous technique under the monitor of radiation, which is a nonvisualized procedure. OBJECTIVE: Our study aimed to assess the feasibility of percutaneous endoscope-assisted visualized implantation approach for PEs, delineating its specific merits and demerits compared to the traditional method. STUDY DESIGN: Laboratory study with Institutional Review Board Number B2023-056SETTING: Clinical Anatomy Research Center, Fudan University. METHODS: Eight freshly procured adult cadavers (4 women and 4 men) were operated on in this study. They were divided into either Group A or Group B, each encompassing 4 cadavers. Group A was subjected to endoscope-assisted PEs implantation, whereas Group B followed the conventional PEs implantation route.In both groups the operative time of introducer needles placement (OTNP), total operative time (TOT), fluoroscopy time of introducer needles placement (FTNP), and total fluoroscopy time (TFT) were documented and analyzed. Furthermore, the precise positioning of the PEs and any ensuing complications were systematically examined. RESULTS: Both Group A and Group B successfully executed all predetermined surgical steps. A total of 16 PEs were implanted (dual electrodes in each cadaver): 8 using the percutaneous endoscope-assisted visualized approach (Group A) and 8 via the traditional methodology (Group B). Group A's mean ± SD durations for OTNP, TOT, FTNP, and TFT were 10.25 ± 1.03 minutes, 31.63 ± 5.87 minutes, 4.58 ± 1.35 seconds, and 43.73 ± 14.46 seconds, respectively. In contrast, Group B exhibited mean ± SD times of 11.55 ± 2.81 minutes, 44.75 ± 7.85 minutes, 23.53 ± 4.16 seconds, and 66.30 ± 6.35 seconds for the same metrics. No discernible statistical difference in OTNP and TOT emerged between the groups. However, Group A demonstrated reduced durations for both FTNP and TFT compared to Group B. The optimal position of the PEs was verified via fluoroscopy, with no recorded instances of dura rupture. These outcomes suggest that this endoscope-assisted technique neither increases surgical time nor compromises efficacy. Instead, it leads to a marked reduction in fluoroscopic duration relative to the traditional methodology. LIMITATIONS: Anatomical study on a human cadaver, the quantity of cadavers, and the procedure's steep learning curve. CONCLUSION: With the assistance of percutaneous spinal endoscopy, introducer needles can be punctured through the ligamentum flavum at the anticipated interlaminar window locus under direct visualization, improving the convenience of the puncture and reducing fluoroscopic exposure. It is a viable alternative for surgeons from diverse training backgrounds to implant PEs, particularly benefiting those well-versed in endoscopic spine surgery techniques.

Spinal Cord Stimulation Modulates Rat Cortico-Basal Ganglia Locomotor Circuit.

OBJECTIVE: The cortico-basal ganglia circuit is crucial to understanding locomotor behavior and movement disorders. Spinal cord stimulation modulates that circuit, which is a promising approach to restoring motor functions. However, the effects of electrical spinal cord stimulation in the healthy brain motor circuit in pre- and postgait are poorly understood. Thus, this report aims to evaluate, through electrophysiological analyses, the dynamic spectral features of motor networks underlying locomotor initiation with spinal cord stimulation. MATERIALS AND METHODS: Wistar male rats underwent spinal cord stimulation (current 30-150 µA, frequency 100, 333, and 500 Hz) with the electrophysiological recording of the caudate and putamen nuclei, primary and secondary motor cortices, and primary somatosensory cortex. Video tracking recorded treadmill locomotion and extracted the motor planning and gait initiation. RESULTS: Spectral analysis of segments of gait initiation (pre- and postgait), with stimulation off, showed increased low-frequency activity. Postgait initiation showed increased alpha and beta rhythms and decreased delta rhythm with the stimulation off. Overall, the stimulation frequencies reduced alpha and beta rhythms in all brain areas during movement initiation. Regarding movement planning, such an effect was observed in the sensorimotor area, comprising the delta and alpha rhythms. CONCLUSION: This study showed a short-term effect of spinal cord stimulation on the brain areas of the motor circuit, suggesting possible facilitation of movement planning and starting through neuromodulation. Thus, the electrophysiological characterization of this study may contribute to understanding basal ganglia networks and developing new approaches to treat movement disorders in the gait initiation phase.

Spinal Cord Stimulation Improves Quality of Life for Patients With Chronic Pain-Data From the UK and Ireland National Neuromodulation Registry.

INTRODUCTION: Spinal cord stimulation (SCS) is a well-established treatment for chronic pain and is supported by numerous studies. However, some recent articles have questioned its efficacy. This article examines a cohort of >1800 patients with SCS from the UK and Ireland National Neuromodulation Registry. It is intended to provide a "real-world" assessment of efficacy and compare its effects with other procedures performed for painful indications. MATERIALS AND METHODS: Quality of life (QoL) data (EuroQoL five-level [EQ5D]) and demographic data were extracted from the National Neuromodulation Registry for all patients (N = 1811) who underwent SCS for chronic pain in 27 centers in the UK between February 2018 and July 2022. These were compared with data from the published literature for other commonly performed elective surgical procedures. RESULTS: The EQ5D utility index increased by a mean of 0.202 in the 1236 patients with paired pre- and postoperative utility scores. The median utility was 0.263 (interquartile range [IQR] = 0.384; n = 1811) preoperatively, whereas at six months after the operation, it was 0.550 (IQR = 0.396; n = 1025), p < 0.0001, Wilcoxon rank sum test. The median utility score at 12 months postoperation was 0.548 (IQR = 0.417; n = 970). There was no difference in utility scores at six months and 12 months after implantation (p = 0.15, Wilcoxon rank sum test). There was a significant improvement in QoL in all five domains of the five-level EQ5D tool at six months after baseline (p < 0.01, for all subcategories), and this was sustained at one year after implantation. The baseline utility was lower than in patients who underwent elective surgery for other painful conditions, and the absolute (and proportionate) increase in utility produced by SCS was greater than that achieved with most other interventions. CONCLUSIONS: SCS increases the QoL in patients requiring surgery for pain. Similar results were seen regardless of SCS indication. When comparing analogous data bases, SCS produces a greater percentage improvement in EQ5D utility than do many other elective surgical procedures for painful conditions, including spinal surgery and some joint replacements.

A preliminary study exploring the effects of transcutaneous spinal cord stimulation on spinal excitability and phantom limb pain in people with a transtibial amputation.

Objective. Phantom limb pain (PLP) is debilitating and affects over 70% of people with lower-limb amputation. Other neuropathic pain conditions correspond with increased spinal excitability, which can be measured using reflexes andF-waves. Spinal cord neuromodulation can be used to reduce neuropathic pain in a variety of conditions and may affect spinal excitability, but has not been extensively used for treating PLP. Here, we propose using a non-invasive neuromodulation method, transcutaneous spinal cord stimulation (tSCS), to reduce PLP and modulate spinal excitability after transtibial amputation.Approach. We recruited three participants, two males (5- and 9-years post-amputation, traumatic and alcohol-induced neuropathy) and one female (3 months post-amputation, diabetic neuropathy) for this 5 d study. We measured pain using the McGill Pain Questionnaire (MPQ), visual analog scale (VAS), and pain pressure threshold (PPT) test. We measured spinal reflex and motoneuron excitability using posterior root-muscle (PRM) reflexes andF-waves, respectively. We delivered tSCS for 30 min d-1for 5 d.Main Results. After 5 d of tSCS, MPQ scores decreased by clinically-meaningful amounts for all participants from 34.0 ± 7.0-18.3 ± 6.8; however, there were no clinically-significant decreases in VAS scores. Two participants had increased PPTs across the residual limb (Day 1: 5.4 ± 1.6 lbf; Day 5: 11.4 ± 1.0 lbf).F-waves had normal latencies but small amplitudes. PRM reflexes had high thresholds (59.5 ± 6.1µC) and low amplitudes, suggesting that in PLP, the spinal cord is hypoexcitable. After 5 d of tSCS, reflex thresholds decreased significantly (38.6 ± 12.2µC;p< 0.001).Significance. These preliminary results in this non-placebo-controlled study suggest that, overall, limb amputation and PLP may be associated with reduced spinal excitability and tSCS can increase spinal excitability and reduce PLP.

Ten-kHz Spinal Cord Stimulation vs Radiofrequency Ablation of Splanchnic Nerves: A Single-Site Retrospective Comparison of 12-Month Outcomes.

OBJECTIVES: A prospective study on 10-kHz spinal cord stimulation (SCS) for various causes of chronic abdominal pain (CAP) showed robust improvements in subjects' pain and function. Radiofrequency ablation of splanchnic nerves (snRFA) has been used in advanced pain management treatment algorithms for CAP. This analysis was designed to provide what we believe is the first comparison of the efficacy of these two therapies. Propensity-score matched analysis (PMA) was performed to compare pain relief and decrease in medication usage in snRFA and SCS for treating refractory CAP. MATERIALS AND METHODS: Medical records were extracted for consecutive patients with CAP treated from June 2015 to June 2021 who underwent either snRFA or SCS at the Carolinas Pain Institute after positive diagnostic splanchnic block. The patients' diagnoses included gastroparesis, chronic pancreatitis, postsurgical CAP, and other dysmotility syndromes. PMA was performed to produce matched pairs in terms of baseline clinical status, reported pain, and opioid use over 12 months, after treatment was compared in the groups. RESULTS: PMA produced two well-balanced groups (n = 31) for SCS and snRFA. Analysis showed significant improvement in pain scores in both groups through 12 months, but the mean reduction in reported numerical rating scale points was significantly greater for the SCS group, averaging 4.7 vs 3.0 points for the snRFA group (p < 0.01). Responder rates (≥50% pain relief) similarly diverged at 12 months, with 67.7% vs 30.0% responders in the SCS and snRFA groups, respectively (p = 0.017). Opioid usage did not change in the snRFA group but was reduced in the SCS group at 12 months (p = 0.004). CONCLUSIONS: SCS provided longer pain relief than did snRFA in this propensity-matched study. Pain scores and opioid usage were significantly less at 12-month follow-up when SCS was used for control of CAP.

Improving neurological deficits secondary to transverse myelitis using epidural spinal cord stimulation: illustrative cases.

BACKGROUND: Epidural spinal cord stimulation (eSCS) is canonically used for the treatment of intractable, chronic pain. Recent efforts have successfully utilized eSCS to improve neurological deficits in patients with spinal cord injury. However, there is a paucity of literature on the use of eSCS for demyelinating conditions, with no prior case reports examining eSCS among patients with transverse myelitis (TM). OBSERVATIONS: Two patients with TM underwent eSCS and experienced improvements in motor function and bladder symptoms. The first patient exhibited enhanced motor strength in both lower extremities and no longer experienced leg spasms, increasing exercise capacity and decreasing their fall risk. The patient had reduced incontinence pad usage due to a regained ability to sense bladder fullness. The second patient also experienced improved motor scores, leading to enhanced motor functionality and independence. Furthermore, the patient observed reductions in urinary tract infections post-eSCS. Neither patient reported substantial improvement in bowel function following stimulation. LESSONS: Improvements in motor functionality and bladder functioning are well-documented as factors that improve quality of life among paraplegic patients. Given the findings of the present case report, larger cohort studies examining the use of eSCS for demyelinating conditions, including TM, are warranted. https://thejns.org/doi/10.3171/CASE24152.

New Perspectives for Spinal Cord Stimulation in Parkinson's Disease-Associated Gait Impairment: A Systematic Review.

Parkinson's Disease is a neurodegenerative disorder manifesting itself as a hypokinetic movement impairment with postural instability and gait disturbance. In case of failure and/or limited response, deep brain stimulation has been established as an alternative and effective treatment modality. However, a subset of PD patients with gait impairment represents a therapeutic challenge. A systematic review (2000-2023) was performed using PubMed, Embase, Web of Science, Scopus, and Cochrane Library databases to determine the efficacy, stimulation waveform/parameters, spine level, and outcome measures of spinal cord stimulation using different waveforms in PD patients with and without chronic pain. Spinal cord stimulation responsiveness was assessed within the pre-defined follow-up period in three groups (short-term follow-up = 0-3 months; intermediate follow-up = 3-12 months; and long-term follow-up = more than 12 months). In addition, we briefly outline alternative neurostimulation therapies and the most recent developments in closed-loop spinal cord stimulation relevant to PD. In summary, 18 publications and 70 patients from uncontrolled observational trials were included, with low-quality evidence and conflicting findings. First and foremost, the currently available data do not support the use of spinal cord stimulation to treat PD-related gait disorders but have confirmed its usefulness for PD-associated chronic pain.

Cardiac sensing at a spinal cord stimulation lead: a promising on-device potential biomarker for pain and wellbeing.

Introduction: In the search for objective measures of therapeutic outcomes for patients with spinal cord stimulation (SCS) devices, various metrics of cardiac performance have been linked to pain as well as overall health. To track such measures at home, recent studies have incorporated wearables to monitor cardiac activity over months or years. The drawbacks to wearables, such as patient compliance, would be obviated by on-device sensing that incorporates the SCS lead. This study sought to evaluate the feasibility of using SCS leads to record cardiac electrograms. Methods: The quality of signals sensed by externalized, percutaneous leads in the thoracic spine of 10 subjects at the end of their SCS trial were characterized across various electrode configurations and postures by detecting R-peaks and calculating signal-to-noise ratio (SNR). In a subset of 5 subjects, cardiac metrics were then compared to those measured simultaneously with a wearable. Results: The average signal quality was acceptable for R-peak detection (i.e., SNR > 5) for all configurations and positions across all 10 subjects, with higher signal quality achieved when recording in resting positions. Notably, the spinal lead recordings enabled more reliable beat detection compared to the wearable (n = 29 recording pairs; p < 0.001). When excluding wearable recordings with over 35% missed beats, the inter-beat intervals across devices were highly correlated (n = 22 recording pairs; Pearson correlation: R = 0.99, p < 0.001). Further comparisons in these aligned wearable and corresponding spinal-lead recordings revealed significant differences in the frequency domain metrics (i.e., absolute and normalized high and low frequency HRV power, p < 0.05), but not in time domain HRV parameters. Discussion: The ability of an implanted SCS system to record electrocardiograms, as demonstrated here, could provide the basis of automated SCS therapy by tracking potential biomarkers of the patient's overall health state without the need for additional external devices.

Comparing Conventional Medical Management to Spinal Cord Stimulation for the Treatment of Low Back Pain in a Cohort of DISTINCT RCT Patients.

Aim: Low Back Pain (LBP) is a prevalent condition. Spinal cord stimulation (SCS) has emerged as a more effective, long-term treatment compared to conventional medical management (CMM). The DISTINCT study enrolled and randomized chronic LBP patients with no indication of traditional spine surgery. This analysis focuses comparing study outcomes on patients initially randomized to receive CMM treatment and subsequently crossed over to SCS after 6 months. Purpose: To compare the therapeutic effectiveness and cost-efficiency of passive recharge burst SCS to CMM. Patients and Methods: A total of 269 patients were enrolled with 162 randomly assigned to SCS and 107 to CMM. The DISTINCT study design allowed a crossover to the alternative treatment arm after 6 months. Patients underwent a trial and received a permanent implant if they reported ≥50% pain reduction. Outcome analysis included pain (NRS), disability (ODI), catastrophizing (PCS), quality of life (PROMIS-29) and health care utilization. Results: Seventy out of eighty-one patients opted to cross over to trial SCS at 6M with 94% (66/70) undergoing a trial. Among those, 88% (58/66) reported a ≥50% or more pain relief and 55 received a permanent implant. At 12M visit, 71.4% reported a ≥50% pain improvement sustained at the 18M visit, with 24.5% (12/49) indicating a ≥80% improvement. Disability reductions (79% meeting the minimally important difference of a 13-point decrease), decreased catastrophizing, and significant improvements in all PROMIS-29 domains were noted. Furthermore, 42% of the patients reported decreased or discontinued opioid usage. Clinical benefits at the 12M visit were sustained through the 18M visit accompanied by a significant reduction in healthcare utilization and a $1214 cost savings. Conclusion: SCS demonstrates superior, long-term performance and safety outcomes compared to CMM therapy in LBP patients who received both CMM and SCS therapy. Additionally, SCS patients experienced reduced healthcare resource utilization and lower costs compared to those receiving CMM.

Motor point stimulation activates fewer Ia-sensory nerves than peripheral nerve stimulation in human soleus muscle.

Peripheral nerve stimulation (PNS) and motor point stimulation (MPS) are non-invasive techniques employed to induce muscle contraction, aiding motor function restoration in individuals with neurological disorders. Understanding sensory inputs from PNS and MPS is crucial for facilitating neuroplasticity and restoring impaired motor function. Although previous studies suggest that MPS could induce Ia-sensory inputs less than PNS, experimental evidence supporting this claim is insufficient. Here, we implemented a conditioning paradigm combining transcutaneous spinal cord stimulation (tSCS) with PNS or MPS to investigate their Ia-sensory inputs. This paradigm induces post-activation depression of spinal reflexes associated with transient decreases in neurotransmitter release from Ia-afferent terminals, allowing us to examine the Ia-sensory input amount from PNS and MPS based on the depression degree. We hypothesized that MPS would induce less post-activation depression than PNS. Thirteen individuals underwent MPS and PNS on the soleus muscle as conditioning stimuli, with tSCS applied to the skin between the spinous processes (L1-L2) as test stimuli. PNS- and MPS-conditioned spinal reflexes were recorded at five inter-stimulus intervals (ISIs) and four intensities. Results revealed that all PNS conditioning showed significant decreases in spinal reflex amplitudes, indicating post-activation depression. Furthermore, PNS conditioning exhibited greater depression for shorter ISIs and higher conditioning intensities. In contrast, MPS conditioning demonstrated intensity-dependent depression, but without all-conditioning depression and clear ISI dependency as seen in PNS conditioning. Additionally, PNS induced significantly greater depression than MPS across most conditions. Our findings provide experimental evidence supporting the conclusion that MPS activates Ia-sensory nerves less than PNS.

Clinical Outcome After Epidural Spinal Cord Stimulation in Patients With Severe Traumatic Brain Injury.

INTRODUCTION:  Epidural spinal cord stimulation is a minimally invasive procedure with a growing list of indications. It has a good safety profile and analgesic effect, reduces the severity of spasticity, and activates various brain regions. The purpose of this study is to evaluate the clinical outcome of epidural spinal cord stimulation in patients with spastic syndrome and chronic disorders of consciousness resulting from severe traumatic brain injury (sTBI). METHODS: Between 2021 and 2023, an epidural spinal cord stimulation test was performed in 34 patients with central paresis, severe hypertonia, and chronically altered consciousness following sTBI. The severity of spastic syndrome was assessed using a modified Ashworth scale. All patients underwent implantation of a cylindrical eight-contact test epidural electrode at C3-C5 cervical level, followed by neurostimulation and selection of individual modes. Tonic stimulation at a frequency of 60 Hz, "burst" mode, or a combination of the two was used. RESULTS:  Epidural spinal cord stimulation was administered for an average of 4 ± 1.5 days, with tonic stimulation mode applied in 15 (44.1%) patients, "burst" mode in 10 (29.4%), and a combination of two in nine (26.5%) patients. A reduction in spasticity with clinical improvement was observed in 21 patients (61.8%). The Ashworth scale scores for distal and proximal upper extremities decreased from 3 points to 2.5 points and from 3 points to 2 points, respectively. This was significant in the right upper limbs (p = 0.0152 distally and p = 0.0164 proximally). Significant improvements were also seen in the lower extremities. Active movements in paretic limbs increased or appeared in 12 patients (35.3%), while a heightened level of consciousness was observed in six patients (17.6%). Permanent neurostimulator implantation was performed in 12 patients (35.3%), with no reported surgical complications. CONCLUSION:  Epidural spinal cord stimulation shows promise as an invasive rehabilitation method for patients with sTBI sequelae. Its use reduced the severity of spastic syndrome in over half of patients and increased active movements in paretic limbs in over a third. Notably, neuromodulation at the cervical level yielded pronounced effects on the upper extremities, both proximally and distally. Findings regarding consciousness level improvement are particularly intriguing but warrant further validation through randomized trials.