Correlation Between Aspects of Perceived Patient Loneliness and Spinal Cord Stimulation Outcomes

ObjectivesLoneliness as a whole has been characterized as a health-related risk factor and is associated with worse outcomes after cardiac procedures. Evidence suggests that chronic pain patients are particularly vulnerable to feeling lonely. We examined the relationship between different aspects of loneliness and one-year postoperative outcomes after spinal cord stimulation (SCS) for chronic pain.Materials and MethodsWe contacted 69 patients with thoracic SCS who had participated in our prospective outcomes database with one-year follow-up to complete the validated, abbreviated UCLA Loneliness Scale (UCLA-3). We examined responses on question 9 of the Oswestry Disability Index (ODI), question 12 of the Beck Depression Inventory (BDI), and UCLA-3 due to their relevance to different aspects of loneliness. We conducted regression analyses to determine the relationship between aspects of loneliness and pain outcomes.ResultsWe identified that loss of interest in people, companionship, and feeling excluded were associated with pain outcomes. Loss of interest in people was associated with improvement in pain (NRS worst p = 0.021, r = 0.32, NRS least p = 0.004, r = 0.4; NRS right now p = 0.016, r = 0.33). Companionship and feeling excluded were also associated with pain. We examined the interface between depression and total loneliness and found that while both were related to each other, depression was not associated with pain outcomes.ConclusionsThis study demonstrates an association between loss of interest in people, companionship, and feeling excluded and worse postoperative pain outcomes after receiving SCS. It identifies aspects of loneliness as important factors to consider when predicting the outcomes of SCS therapy for chronic pain control.     

One-Year Results of Prospective Research Study Using 10 kHz Spinal Cord Stimulation in Persistent Nonoperated Low Back Pain of Neuropathic Origin: Maiden Back Study

PurposeSpinal cord stimulation (SCS) is a recommended treatment for chronic neuropathic pain. Persistent nonoperative low back pain of neuropathic origin has profound negative impacts on patient’s lives. This prospective, open label, research study aimed to explore the use of SCS in patients with associated features of central sensitisation such as allodynia and hyperalgesia.Materials and MethodsTwenty-one patients with back pain and hyperalgesia or allodynia who had not had prior spinal surgery underwent a SCS trial followed by full implantation. SCS comprised administering electrical impulses epidurally at a frequency of 10 kHz and pulse width of 30 μsec. Patients attended follow-up visits after 6 and 12 months of SCS. Repeated measure ANOVAs/Friedman tests explored change after 6 and 12 months of 10 kHz SCS. Independent sample t-tests/Mann–Whitney U tests examined differences in response after 12 months of 10 kHz SCS.ResultsBack and leg pain, quality of life (QoL), pain-related disability, and morphine equivalence significantly improved compared with baseline following 6 and 12 months of 10 kHz SCS. There were no increases in the consumption of opioids, amitriptyline, gabapentin or pregabalin in any patient. After 12 months of treatment, 52% encountered ≥50% improvement in back pain, 44% achieved remission (0–3 cm back pain VAS), 40% reported ODI scores between 0 and 40 and 60% experienced a reduction of at least 10 ODI points. Patients reporting ≥10-point improvement in ODI had significantly longer pain history durations and experienced significantly greater improvements in back pain, leg pain and QoL than those reporting <10-point improvement in ODI.ConclusionThe 10 kHz SCS improved back and leg pain, QoL, pain-related disability and medication consumption in patients with nonoperative back pain of neuropathic origin. With further research incorporating a sham control arm, the efficacy of 10 kHz SCS in this patient cohort will become more established.     

Pain and Interoceptive Awareness Outcomes of Chronic Pain Patients With Spinal Cord Stimulation

ObjectivesMeditation has been shown to improve outcomes for chronic pain by increasing patients’ awareness of their own bodies. Some patients have an innate ability to leverage their mind–body connection, and this interoceptive awareness may aid them in garnering pain relief. We explored whether spinal cord stimulation (SCS) patients with greater innate awareness had better outcomes.Materials and MethodsWe contacted 30 thoracic SCS patients with baseline and postoperative pain, psychological, and disability outcomes to complete the Multidimensional Assessment of Interoceptive Awareness (MAIA) survey. MAIA distinguishes between beneficial and maladaptive aspects of the perception of body sensations via six positive subscales (noticing, attention regulation, emotional awareness, self-regulation, body listening, and trusting) and two negative subscales (not distracting, not worrying). MAIA subscales and positive/negative groups were correlated with percentage change in Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), Beck’s Depression Inventory (BDI), Pain Catastrophizing Scale (PCS), and McGill Pain Questionnaire (MPQ).ResultsPatients included 14 males/16 females with a mean age of 58. At a mean follow-up of 14.13 months (range 6–26), NRS, ODI, BDI, PCS, and MPQ showed improvements. Positive traits correlated with improvements in pain (MAIA-self regulation with NRS-worst [p = 0.018], NRS-least [p = 0.042], NRS-average [p = 0.006], NRS-current [p = 0.001]; MAIA-body listening with MPQ-total [p = 0.016] and MPQ-sensory [p = 0.026]). Improvement in PCS-total was associated with higher scores in noticing (p = 0.002), attention regulation (p = 0.017), emotional awareness (p = 0.039), and trusting (p = 0.047). PCS-rumination correlated with MAIA-positive total (p = 0.012). In contrast, better attention regulation signified less improvement in ODI (p = 0.043) and MPQ affective (p = 0.026).ConclusionsHigher interoceptive awareness in SCS patients correlated with greater improvement following the procedure, particularly with regards to pain relief and pain catastrophizing. These findings suggest that patients with better mind–body connections may achieve greater pain relief following SCS in this patient population, thereby aiding providers in determining who may benefit from this intervention.     

Pain Catastrophizing Does Not Predict Spinal Cord Stimulation Outcomes: A Cohort Study of 259 Patients With Long‐Term Follow‐Up

ObjectiveSpinal cord stimulation (SCS) is an important treatment modality used to treat chronic neuropathic pain. However, reported success rates of 26%-70% entail an increased focus on patient selection. An area of core interest is psychological evaluation, often using scales such as the Pain Catastrophizing Scale (PCS). The aim of this study was to assess the relation between baseline PCS scores obtained before implantation and SCS outcomes defined as (1) Rating on Patients’ Global Impression of Change scale (PGIC), (2) Pain relief on the Numeric Rating Scale (NRS), (3) Cessation of pain medication, and (4) Risk of permanent explantation.Materials and MethodsUsing records from the Neurizon Neuromodulation Database, we performed a multicenter open cohort study of 259 permanently implanted SCS patients. Follow-up ranged from six months to nine years (median = three years). For each of the defined SCS outcomes, patients were grouped according to their latest follow-up registration. Subsequently, we used a one-way ANOVA and exact t-tests to compare mean baseline PCS scores between groups.ResultsNo difference in mean baseline PCS scores was found between PGIC groups. Baseline PCS scores was not associated with the probability of obtaining 30% or 50% pain relief on latest registration. Baseline PCS scores of patients able to cease all usage of tricyclic antidepressants, antiepileptics, or opioids during SCS treatment did not differ from baseline scores of continuous users. We found no association between baseline PCS scores and risk of permanent explantation.ConclusionThis study did not demonstrate any associations between baseline PCS scores and SCS outcomes.     

Long-Term Outcomes of Spinal Cord Stimulation With Paddle Leads in the Treatment of Complex Regional Pain Syndrome and Failed Back Surgery Syndrome

Introduction: Spinal cord stimulation (SCS) is frequently used to treat chronic, intractable back, and leg pain. Implantation can be accomplished with percutaneous leads or paddle leads. Although there is an extensive literature on SCS, the long‐term efficacy, particularly with paddle leads, remains poorly defined. Outcome measure choice is important when defining therapeutic efficacy for chronic pain. Numerical rating scales such as the NRS‐11 remain the most common outcome measure in the literature, although they may not accurately correlate with quality of life improvements and overall satisfaction. Methods: We reviewed the medical records of patients with failed back surgery syndrome (FBSS) or complex regional pain syndrome (CRPS) implanted with SCS systems using paddle leads between 1997 and 2008 at the Cleveland Clinic with a minimum six‐month follow‐up. Patients were contacted to fill out a questionnaire evaluating outcomes with the NRS‐11 as well as overall satisfaction. Results: A total of 35 eligible patients chose to participate. More than 50% of the patients with CRPS reported greater than 50% pain relief at a mean follow‐up of 4.4 years. Approximately 30% of the FBSS patients reported a 50% or greater improvement at a mean follow‐up of 3.8 years. However, 77.8% of patients with CRPS and 70.6% of patients with FBSS indicated that they would undergo SCS surgery again for the same outcome. Conclusion: Patients with CRPS and FBSS have a high degree of satisfaction, indexed as willingness to undergo the same procedure again for the same outcome at a mean follow‐up of approximately four years. The percentage of satisfaction with the SCS system is disproportionally greater than the percentage of patients reporting 50% pain relief, particularly among patients with FBSS. This suggests that the visual analog scale may not be the optimal measure to evaluate long‐term outcomes in this patient population.     

Comparison of Spinal Cord Stimulation Outcomes Between Preoperative Opioid Users and Nonusers: A Cohort Study of 467 Patients

ObjectivesSpinal cord stimulation (SCS) is a surgical treatment modality reserved for a subset of patients with neuropathic pain in which conventional pharmacologic treatment has proven insufficient. Previous studies have suggested a possible negative relationship between opioid use at referral and subsequent success of SCS therapy. The aim of this cohort study was to investigate whether preoperative opioid use was associated with inferior SCS outcomes.Materials and MethodsData were obtained from the Danish Neurizon Neuromodulation Database and comprised preoperative registrations of analgesic use, postoperative Patients’ Global Impression of Change (PGIC) ratings, pre- and postoperative pain intensity scores (Numeric Rating Scale), and detailed surgical data. Patients were dichotomized according to preoperative opioid use (users vs nonusers) with subsequent assessment of the latest PGIC rating, reduction in pain intensity, and current treatment status (implanted/explanted). In addition, daily preoperative opioid dosages were quantified in oral morphine equivalents (OME) and correlated to the treatment outcomes.ResultsA total of 467 patients were included; 296 consumed opioids before SCS implantation (median 80 OME/d). Preoperative opioid use was not associated with the latest PGIC rating, reduction in pain intensity (30% or 50%), or risk of undergoing explantation (median follow-up = 3.0 years). Likewise, preoperative median OME per day of opioid users was not correlated with any of the defined outcomes.ConclusionsPreoperative opioid usage did not predict the outcome of SCS therapy in a large cohort of patients permanently implanted with an SCS system. The results do not support withholding otherwise well-indicated SCS therapy in patients with chronic neuropathic pain conditions based merely on preoperative opioid usage.     

Spinal Cord Stimulation With Additional Peripheral Nerve/Field Stimulation Versus Spinal Cord Stimulation Alone on Back Pain and Quality of Life in Patients With Persistent Spinal Pain Syndrome

IntroductionPersistent spinal pain syndrome (PSPS) or failed back surgery syndrome (FBSS) refers to new or persistent pain following spinal surgery for back or leg pain in a subset of patients. Spinal cord stimulation (SCS) is a neuromodulation technique that can be considered in patients with predominant leg pain refractory to conservative treatment. Patients with predominant low back pain benefit less from SCS. Another neuromodulation technique for treatment of chronic low back pain is subcutaneous stimulation or peripheral nerve field stimulation (PNFS). We investigated the effect of SCS with additional PNFS on pain and quality of life of patients with PSPS compared with that of SCS alone after 12 months.Materials and MethodsThis is a comparative study of patients with PSPS who responded to treatment with either SCS + PNFS or SCS only following a multicenter randomized clinical trial protocol. In total, 75 patients completed the 12-month follow-up: 21 in the SCS-only group and 54 in the SCS + PNFS group. Outcome measures were pain (visual analog scale), quality of life (36-Item Short Form Survey [SF-36]), anxiety and depression (Hospital Anxiety and Depression Scale [HADS]), overall health (EuroQol Five-Dimension [EQ-5D]), disability (Oswestry Disability Index [ODI]), and pain assessed by the McGill questionnaire.ResultsThere were no significant differences in baseline characteristics between the two groups. Both groups showed a significant reduction in back and leg pain at 12 months compared with baseline measurements. No significant differences were found between the groups in effect on both primary (pain) and secondary parameters (SF-36, HADS, EQ-5D, ODI, and McGill pain).ConclusionIn a subgroup of patients with chronic back and leg pain, SCS alone provided similar long-term pain relief and quality-of-life improvement as PNFS in addition to SCS. In patients with refractory low back pain not responding to SCS alone, adding PNFS should be recommended.Clinical Trial RegistrationThe Clinicaltrials.gov registration number for the study is NCT01776749.     

Allodynia,Hyperalgesia, (Quantitative) Sensory Testing and Conditioned Pain Modulation in Patients With Complex Regional Pain Syndrome Before and After Spinal Cord Stimulation Therapy

ObjectivesComplex regional pain syndrome (CRPS) is a chronic debilitating disease characterized by sensory abnormalities. Spinal cord stimulation (SCS) is an effective therapy for CRPS, but few studies have investigated the effects of SCS therapy on sensory characteristics. Therefore, this study investigated the effect of SCS on allodynia, hyperalgesia, electrical quantitative sensory testing (QST) parameters, and conditioned pain modulation (CPM) effect.Materials and MethodsThis study is part of a multicenter randomized controlled trial (ISRCTN 36655259). Patients with CRPS in one extremity and eligible for SCS were included. The outcome parameters allodynia (symptom and sign), hyperalgesia (symptom), sensory thresholds with QST, CPM effect, and pain scores were tested before and after three months of SCS (40-Hz tonic SCS). Both the CRPS-affected extremity and the contralateral, clinically unaffected extremity were used to test three sensory thresholds with electrical QST: current perception threshold (CPT), pain perception threshold (PPT), and pain tolerance threshold (PTT). The PTT also was used as a test stimulus for the CPM paradigm both before and after the conditioning ice-water test. Nonparametric testing was used for all statistical analyses.ResultsIn total, 31 patients were included for analysis. Pain, allodynia (sign and symptom), and hyperalgesia (symptom) were all significantly reduced after SCS therapy. On the unaffected side, none of the QST thresholds (CPT, PPT, and PTT) was significantly altered after SCS therapy. However, the CPT on the CRPS-affected side was significantly increased after SCS therapy. A CPM effect was present both before and after SCS.ConclusionsStandard 40-Hz tonic SCS significantly reduces pain, hyperalgesia, and allodynia in patients with CRPS. These findings suggest that SCS therapy should not be withheld from patients who suffer from allodynia and hyperalgesia, which contradicts previous findings derived from retrospective analysis and animal research.ISRCTN Registry: The ISRCTN registration number for the study is ISRCTN 36655259.     

Cascade Programming for 10 kHz Spinal Cord Stimulation: A Single Center Case Series of 114 Patients With Neuropathic Back and Leg Pain

ObjectiveTen kilohertz spinal cord stimulation (SCS) is usually initiated in a single-bipolar configuration over the radiological reference point T9/T10 intervertebral disc space for neuropathic back and leg pain. Cascade is a duty-cycled, multi-bipolar contact configuration across an entire eight-contact lead. Potential advantages by using a broader area of SCS coverage include mitigation against minor lead migration and a reduction in the need for reprogramming. We report here the results of a retrospective case series of 114 patients using Cascade.Materials and MethodsRetrospective data were collected over two years. We selected patients with neuropathic back with or without/leg pain who had a trial of SCS. Pain assessments using Numerical Rating Scales (NRS) and Patient Global Impression of Change (PGIC) scores were collected at baseline, six months, and last follow-up beyond 12 months (mean 15.1 months). Patients were programmed with 10 kHz SCS using Cascade during the trial, which was continued unless reporting inadequate pain relief. Morbidity and deviations from Cascade programming were also obtained.ResultsAt six months, 87 of 97 (90.6%) patients with active devices were using Cascade and 58 of 72 (81%) patients at the last follow-up >12 months. There was a significant reduction in back NRS (8.3 vs. 3.9 [p < 0.0001], N = 97) and leg pain (7.53 vs. 3.83 [p < 0.0001], N = 77) at 6 months and last follow-up >12 months back (8.3 vs. 3.95 [p < 0.0001] N = 72), leg (7.53 vs. 3.534 [p < 0.0001], N = 58). The PGIC score was 6 of 7 or all of 7 in 72% of patients (70/97) at six months and in 68% (49/72) of patients at the last follow-up beyond 12 months.ConclusionCascade is an effective programming methodology that may have benefits over a single-bipole configuration for 10 kHz SCS, particularly during a trial of stimulation. Results from this study suggest it is a durable program for patients with neuropathic back and leg pain.     

1.2 kHz High-Frequency Stimulation as a Rescue Therapy in Patients With Chronic Pain Refractory to Conventional Spinal Cord Stimulation

ObjectivesWe aimed to investigate the efficacy of new subperception stimulation paradigms including 1.2 kHz-high-frequency stimulation (HFS) and advanced-HFS field-shaping algorithm (dorsal horn HFS [DHHFS]) in refractory cases which initially benefited from conventional spinal cord stimulation (SCS) and lost the effect throughout time.Materials and MethodsIn the context of a rescue-therapy, patients underwent externalization of the implanted SCS-leads and were tested with multiple combinations of new SCS paradigms. Pain intensity was analyzed using the numeric rating scale (NRS), and data were collected preoperatively and at multiple postoperative follow-ups.ResultsThirty-seven patients underwent externalization of the leads. Mean preoperative NRS-score was 8.1/10 points (SD ± 0.9) for the ON-stimulation period. Patients received a combination of either tonic, burst and 1.2 kHz-HFS, or burst and 1.2 kHz-HFS, DHHFS, or 1.2 kHz-HFS and DHHFS, or 1.2 kHz-HFS alone. The mean postoperative NRS-score after the testing-phase was 3.8/10 points (SD ± 2.5), showing a 48.0% mean reduction (p < 0.001). In total, 29 patients reported a significant reduction above 50% in NRS-scores and therefore were reimplanted with new generators that could deliver the new paradigms. Eight patients underwent full SCS-system explantation. The patients who continued with the new paradigms (n = 29) reported mean NRS-scores of 3.5/10 points (SD ± 1.7) 12 months postoperatively, still showing a significant reduction of 43.3% when compared to preoperative scores (p < 0.001).ConclusionRescue-therapy with combination of multiple waveforms, including tonic, burst, 1.2 kHz-HFS, and DHHFS, was associated with a significant pain relief in patients with failed conventional SCS. This approach is a safe and efficient and should be considered before explantation of the SCS-system.     

Dorsal Root Ganglion Stimulation as a Salvage Therapy Following Failed Spinal Cord Stimulation

IntroductionSpinal cord stimulation (SCS) can provide long-term pain relief for various chronic pain conditions, but some patients have no relief with trial stimulation or lose efficacy over time. To “salvage” relief in patients who do not respond or have lost efficacy, alternative stimulation paradigms or anatomical targets can be considered. Dorsal root ganglion stimulation (DRG-S) has a different mechanism of action and anatomical target than SCS.ObjectivesWe assessed DRG-S salvage therapy outcomes in patients who did not respond to SCS or had lost SCS efficacy.Materials and MethodsWe retrospectively included consecutive patients from 2016 to 2020 who were salvaged with DRG-S after failed SCS trials (<50% pain reduction) or who had lost efficacy after permanent SCS. We compared numerical rating scale (NRS) pain, Oswestry disability index (ODI), health-related quality of life (EuroQol five-dimensions five-level), and oral morphine equivalent (OME) opioid requirements before DRG-S salvage and at patients’ last follow-up.ResultsA total of 60 patients who had failed SCS were salvaged with DRG-S. The mean age was 56 ± 12 years, and the most common diagnoses were complex regional pain syndrome (n = 24) and failed back surgery syndrome (n = 24). The most common failed modalities included tonic (n = 32), Burst (n = 18), and high-frequency (n = 10) SCS. The median follow-up duration of salvage DRG-S was 34 months. With DRG-S, NRS decreased (8.7 ± 1.2 to 3.8 ± 2.1), and OME declined (median 23 mg to median 15 mg), whereas EuroQol 5D scores increased (0.40 ± 0.15 to 0.71 ± 0.15), and ODI improved (64 ± 14% to 31 ± 18%) (all p < 0.05).ConclusionsDRG-S can be used in patients with chronic pain who have previously failed to receive persistent benefit from SCS.     

Long-Term Efficacy of a Novel Spinal Cord Stimulation Clinical Workflow Using Kilohertz Stimulation: Twelve-Month Results From the Vectors Study

Background and ObjectivesMultiple variables play a role in spinal cord stimulation (SCS) treatment outcomes, including patient anatomy, pain pattern, lead location, stimulation parameters, and so on. A wide range of stimulation parameters are considered safe and on-label, and as a result a growing number of new frequencies and frequency-combinations are being incorporated into standard practice. A standardized approach to therapy delivery may provide more consistent outcomes for more patients. The Vectors study evaluated whether there is significant sustained improvement in pain and functional outcomes when therapy is delivered using a standardized approach.Materials and MethodsVectors, a post-market, single-arm study evaluated the safety and efficacy of SCS with an implantable neurostimulator starting with 1 kHz stimulation, targeting the T9–T10 disc space following paresthesia mapping. Subjects with chronic intractable low back and leg pain (visual analogue scale [VAS] ≥ 50 mm) were enrolled. The primary endpoint was change in overall pain (VAS) at the three-month visit compared to baseline. Subjects were followed through 12 months. Secondary endpoints included changes in low back and leg pain, quality of life (European Quality of Life – Five Dimensions, EQ-5D-5L), disability (Oswestry Disability Index, ODI), individual subject goals, and subject satisfaction.ResultsThere was a significant reduction in overall pain (VAS; 45.4 mm) through the three-month visit, which was sustained through 12 months. At 12 months, 79% of subjects had ≥50% improvement in at least one pain domain (overall, lowback or leg) with 85% of subjects reporting therapy satisfaction. There was a decrease in disability and an improvement in quality of life with 70% of subjects achieving a personal activity goal by the three-month visit.ConclusionsLong-term pain relief and improvement in quality of life and function were achieved when following a standardized workflow.Clinical Trial RegistrationThe Clinicaltrials.gov registration number for the study is NCT03345472.     

Spinal Cord Stimulation to Treat Low Back Pain in Patients With and Without Previous Spine Surgery

ObjectivesLittle is known about the effects of spinal cord stimulation (SCS) on chronic low back pain (CLBP) patients with no history of previous spine surgery. Using our prospectively collected database, we evaluate improvements in patients with and without previous spine surgery one-year post SCS implantation.Materials and MethodsSubjects completed outcome metrics pre-operatively and one-year post-implantation including Numeric Rating Scale (NRS), McGill Pain Questionnaire (MPQ), Oswestry Disability Index (ODI), Beck’s Depression Inventory (BDI), and Pain Catastrophizing Scale (PCS).ResultsWe enrolled 134 patients; 82 patients had previous spine surgery and 52 patients did not. At one-year post-SCS implantation, patients with previous spine surgery showed improvements in worst pain experienced, least pain experienced, average pain experienced, pain felt currently, MPQ, MPQ sensory, MPQ affective, PCS, PCS helplessness, PCS rumination, PCS magnification, ODI, and BDI scores (p < 0.001, p = 0.005, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.03, p = 0.01, p = 0.02, p < 0.001, p = 0.05, p < 0.001, p = 0.017, respectively). Likewise, patients without previous spine surgery showed improvements in worst pain experienced, least pain experienced, average pain experienced, pain felt currently, MPQ, MPQ sensory, PCS, PCS helplessness, PCS rumination, PCS magnification, ODI, and BDI scores (p < 0.001, p = 0.005, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.008, p < 0.001, p < 0.001, respectively). Patients without previous spine surgery showed greater improvements for average pain PCS helplessness (p = 0.01).ConclusionsPatients with and without previous spine surgery showed similar improvements in pain intensity, pain quality, feelings of rumination and magnification, functional disability, and depression severity. SCS can improve CLBP regardless of whether patients have had previous spine surgery.     

Spinal Cord Stimulation in the Treatment of Cancer Pain: A Retrospective Review

ObjectivesSpinal cord stimulation (SCS) involves electrical stimulation of the dorsal spinal cord to disrupt the transmission of ascending pain signals. SCS has been used successfully to manage a variety of chronic pain conditions, but its efficacy in the treatment of pain syndromes in patients with cancer has not been established because most studies have involved a limited number of patients. The purpose of this study was to assess the efficacy of SCS in a large group of patients with cancer.Materials and MethodsA retrospective review was performed for all patients who had SCS trials and implants placed at Memorial Sloan Kettering Cancer Center between 2003 and 2021. Patients were divided into groups based on whether their pain could be directly attributed to cancer or its treatment (cancer dependent, n = 51) and those who had incidental pain unrelated to cancer (cancer independent, n = 22). The cancer-dependent group was further subdivided into those whose pain was directly related to primary tumor invasion or metastasis (cancer related, n = 26) and those whose pain was a result of cancer treatment such as chemotherapy or surgery (treatment related, n = 25). The primary outcomes were changes in pain scores and daily oral morphine equivalents (OMEs) before intervention to one year after implant. Secondary measures included the SCS trial success rate, change in pain scores immediately after the SCS trial, and change in pain scores immediately after the SCS implant.ResultsMost patients in the cancer-dependent pain group (59%) and the cancer-independent pain group (68%) had successful SCS trials and subsequently went on to have SCS implants placed. The patients with cancer-dependent pain as a whole had median reduction of 1.5 points (or 23%) on a 10-point pain score immediately after implant (p = 0.001), with the effect diminishing to a median reduction of 1 point (or 15%) by one year after implant (p = 0.027). The cancer-dependent pain groups did not have a significant reduction in daily OMEs, following implantation (p = 0.30), but the cancer-independent group did have a significant reduction (p = 0.01).ConclusionsSCS can be considered as a treatment modality for patients with cancer whose pain is not adequately controlled with medical therapy or by less invasive interventions.     

Spinal Cord Stimulation in Complex Regional Pain Syndrome Type I of Less Than 12‐Month Duration

Introduction: Complex regional pain syndrome type 1 (CRPS‐1) has a 31% probability of becoming chronic. The early use of spinal cord stimulation (SCS) has been recommended as a strategy to prevent chronicity and functional impairment. Methods: In a prospective study, we treated 74 CRPS‐1 patients with a mean disease duration of 17 weeks with standard therapy consisting of physical therapy, topical dimethyl sulfoxide, analgesics, transcutaneous stimulation, and sympathetic blockade. Patients who did not respond to standard therapy were offered a treatment with SCS. In these patients, we investigated the impact on pain, quality of life, and function. Results: Out of these 74 patients treated with standard therapy, six patients were included for early SCS treatment. The overall mean pain relief after one year was 35%. The mental component of the Short Form 36 improved; however, there was no effect on the physical component. None of the SCS treated patients showed a clear improvement in functional outcome. Discussion: We conclude that the feasibility of performing a randomized controlled trial on early SCS therapy in CRPS‐1 is low because of the good disease improvement with standard therapy in the first year after onset. This study raises questions about the need to use SCS early in the course of CRPS‐1 because of the probable lack of additional benefit compared with SCS in chronic CRPS‐1.     

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.     

Systematic Literature Review of Spinal Cord Stimulation in Patients With Chronic Back Pain Without Prior Spine Surgery

ObjectiveLow back pain is the leading cause of disability worldwide and one of the most common reasons for seeking health care. Despite numerous care strategies, patients with low back pain continue to exhibit poor outcomes. Spinal cord stimulation (SCS) is an evidence-based therapeutic modality for patients with failed back surgery syndrome. For patients without a surgical lesion or history, minimally invasive interventions that provide long-term reduction of chronic back pain are needed. Therefore, we conducted a systematic review of the evidence on SCS therapy in patients with chronic back pain who have not undergone spinal surgery.Materials and MethodsA systematic literature search was performed to identify studies reporting outcomes for SCS in chronic back pain patients (with or without secondary radicular leg pain) without prior surgery using date limits from database inception to February 2021. Study results were analyzed and described qualitatively.ResultsA total of ten primary studies (16 publications) were included. The included studies consistently demonstrated favorable outcomes in terms of pain reduction and functional improvement following SCS therapy. Improvements also occurred in quality of life scores; however, not all studies reported statistically significant findings. Additionally, the studies reported that SCS resulted in high patient satisfaction, reductions in opioid use, and an acceptable safety profile, although these data were more limited.ConclusionFindings suggest that SCS is a promising, safe, minimally invasive, and reversible alternative option for managing chronic back pain in patients who have not undergone spinal surgery.     

Is Spinal Cord Stimulation Still Effective After One or More Surgical Revisions?

ObjectivesSpinal cord stimulation (SCS) is burdened with surgical complications that may require one or several surgical revision(s), challenging its risk/benefit ratio and cost-effectiveness. Our objective was to evaluate its outcome and efficacy after one or more SCS surgical revisions.Materials and MethodsWe identified and retrospectively analyzed 116 patients treated by tonic paresthesia-based SCS who experienced one or more complication(s) requiring at least one surgical revision. Data collected included initial indication, revision indication, number of revisions, and lead design (paddle or percutaneous). Outcome after SCS revision was evaluated by pain intensity decrease (comparing baseline and postrevision Numerical Rating Scale [NRS] scores) and percentage of patients reporting pain relief ≥50%. Outcome was analyzed according to the number of surgical revisions and the revision indications.ResultsMost of the patients (61%) underwent only one revision (mean delay after implantation 44 months). The most frequent causes of revisions were hardware dysfunction (32%), lead migration (23%), and infection (18%). Revision(s) repaired the SCS issue in 87% of the cases. One year after the first revision, 82% of the patients reported pain relief ≥50%, and the mean NRS decrease was 4.0 compared with baseline (p < 0.001). Benefit of SCS revision tended to decrease with the number of revisions but did not differ across revision indications. No serious surgical complications related to the revision occurred, except for three hematomas occurring after repeated revisions.ConclusionsOur data suggest that surgical revision of SCS system is safe and led to significant pain relief in most of the cases, provided that the initial indication was good and that the previous stimulation was effective. However, success of SCS revision decreases with the number of revisions.     

Applicability and Validity of an e-Health Tool for the Appropriate Referral and Selection of Patients With Chronic Pain for Spinal Cord Stimulation: Results From a European Retrospective Study

ObjectivesTo support rational decision-making on spinal cord stimulation (SCS), a European expert panel developed an educational e-health tool using the RAND/University of California at Los Angeles Appropriateness Method. This retrospective study aimed to determine the applicability and validity of the tool using data from patients for whom SCS had been considered.Materials and MethodsA total of 12 European implant centers retrieved data from 25 to 50 consecutive patients for whom SCS was considered in 2018–2019. For each patient, data were captured on the clinical and psychosocial variables included in the e-health tool, center decisions on SCS, and patient outcomes. Patient outcomes included global perception of effect by the patient and observer, and pain reduction (numeric pain rating scale) at six-month follow-up.ResultsIn total, 483 patients were included, of whom 133 received a direct implant, 258 received an implant after a positive trial, 32 had a negative trial, and 60 did not receive SCS for reasons other than a negative trial. The most frequent indication was persistent spinal pain syndrome type 1 and type 2 (74%), followed by neuropathic pain syndromes (13%), complex regional pain syndrome (12%), and ischemic pain syndromes (0.8%). Data on the clinical and psychosocial variables were complete for 95% and 93% of patients, respectively, and missing data did not have a significant impact on the study outcomes. In patients who had received SCS, panel recommendations were significantly associated with patient outcomes (p < 0.001 for all measures). Substantial improvement ranged from 25% if the e-health tool outcome was “not recommended” to 83% if SCS was “strongly recommended”. In patients who underwent a trial (N = 290), there was 3% of trial failure when SCS was ”strongly recommended” vs 46% when SCS was ”not recommended”.ConclusionsRetrospective application of the e-health tool on patient data showed a strong relationship between the panel recommendations and both SCS trial results and treatment outcomes.