Peripheral Nerve Stimulation: A Treatment for Chronic Low Back Pain and Failed Back Surgery Syndrome?

Objective. This study aims to evaluate the usefulness of peripheral nerve stimulation as a treatment option for patients with chronic low back pain. Materials and Methods. More than 12 months, we collected data on consecutive patients who had successful trials and were subsequently implanted with octrode percutaneous leads placed subcutaneously within the major area of pain. Eleven patients met diagnostic criteria for failed back surgery syndrome. A questionnaire assessed outcomes including: pain, analgesic use, and patient satisfaction. The response rate was 93% (13/14): average follow‐up time was seven months. Results. There was a significant decrease in pain levels: an average reduction of 3.77 visual analog scale points. Eleven patients (85%) reported successful outcomes and an average pain reduction of 4.18 points but two reported a poor response. Pain relief was highly correlated with reduced analgesia and patient satisfaction. No complications were reported. Conclusion. This study demonstrates a treatment option that is safe, nonpharmacologic, reversible, and effective for patients with chronic low back pain that have exhausted other treatment options.     

Deep Brain Stimulation of the Subgenual Cingulate Cortex for the Treatment of Chronic Low Back Pain

ObjectivesDespite converging basic scientific and clinical evidence of the link between chronic pain and depression, existing therapies do not often take advantage of this overlap. Here, we provide a critical review of the literature that highlights the intersection in brain networks between chronic low back pain (CLBP) and depression and discuss findings from previous deep brain stimulation (DBS) studies for pain. Based on a multidimensional model of pain processing and the connectivity of the subgenual cingulate cortex (SCC) with areas that are implicated in both CLBP and depression, we propose a novel approach to the treatment of CLBP using DBS of the SCC.Materials and MethodsA narrative review with literature assessment.ResultsCLBP is associated with a shift away from somatosensory representation toward brain regions that mediate emotional processes. There is a high degree of overlap between these regions and those involved in depression, including the anterior cingulate cortex, medial prefrontal cortex, nucleus accumbens, and amygdala. Whereas target sites from previous DBS trials for pain were not anatomically positioned to engage these areas and their associated networks, the SCC is structurally connected to all of these regions as well as others involved in mediating sensory, cognitive, and affective processing in CLBP.ConclusionsCLBP and depression share a common underlying brain network interconnected by the SCC. Current data and novel technology provide an optimal opportunity to develop clinically effective trials of SCC DBS for CLBP.     

Durability of the Therapeutic Effect of Restorative Neurostimulation for Refractory Chronic Low Back Pain

ObjectivesThe purpose of the ongoing follow-up of ReActiv8-A clinical trial is to document the longitudinal benefits of episodic stimulation of the dorsal ramus medial branch and consequent contraction of the lumbar multifidus in patients with refractory mechanical chronic low back pain (CLBP). We report the four-year outcomes of this trial.Materials and MethodsReActiv8-A is a prospective, single-arm trial performed at nine sites in the United Kingdom, Belgium, and Australia. Eligible patients had disabling CLBP (low back pain Numeric Rating Scale [NRS] ≥6; Oswestry Disability Index [ODI] ≥25), no indications for spine surgery or spinal cord stimulation, and failed conventional management including at least physical therapy and medications for low back pain. Fourteen days postimplantation, stimulation parameters were programmed to elicit strong, smooth contractions of the multifidus, and participants were given instructions to activate the device for 30-min stimulation-sessions twice daily. Annual follow-up through four years included collection of NRS, ODI, and European Quality of Life Score on Five Dimensions (EQ-5D). Background on mechanisms, trial design, and one-year outcomes were previously described.ResultsAt baseline (N = 53) (mean ± SD) age was 44 ± 10 years; duration of back pain was 14 ± 11 years, NRS was 6.8 ± 0.8, ODI 44.9 ± 10.1, and EQ-5D 0.434 ± 0.185. Mean improvements from baseline were statistically significant (p < 0.001) and clinically meaningful for all follow-ups. Patients completing year 4 follow-up, reported mean (±standard error of the mean) NRS: 3.2 ± 0.4, ODI: 23.0 ± 3.2, and EQ-5D: 0.721 ± 0.035. Moreover, 73% of participants had a clinically meaningful improvement of ≥2 points on NRS, 76% of ≥10 points on ODI, and 62.5% had a clinically meaningful improvement in both NRS and ODI and 97% were (very) satisfied with treatment.ConclusionsIn participants with disabling intractable CLBP who receive long-term restorative neurostimulation, treatment satisfaction remains high and improvements in pain, disability, and quality-of-life are clinically meaningful and durable through four years.     

Health Care Resource Utilization of High-Frequency Spinal Cord Stimulation for Treatment of Chronic Refractory Low Back Pain

IntroductionChronic refractory low back pain (CRLBP) is a diagnosis characterized by chronic low back pain in patients who are poor candidates for surgery and fail conservative management. High-frequency spinal cord stimulation (HF-SCS) is a new advance in neuromodulation that may be effective in treating these patients. However, the cost burden of this therapy is yet undetermined.Materials and MethodsIBM MarketScan® (IBM, Armonk, NY) data bases were used to retrospectively identify patients with HF-SCS implantation between 2016 and 2019 in the United States. Those with low back pain diagnosis without history of surgery were included in the cohort. Cost data, including inpatient and outpatient service, medication, and out-of-pocket costs, were collected at six months before HF-SCS implantation and one, three, and six months after implantation. The explant rate within six months was evaluated.ResultsA total of 119 patients met the inclusion criteria. Most patients were female (73.1%) and owned commercial insurance (83.2%). Common comorbidities included inflammatory arthritis (22.7%), depression (26.1%), hypertension (44.5%), and obesity (26.1%). In the six months before HF-SCS implantation, patients incurred median total costs of $15,766 (first quartile [Q1]: $8,847; third quartile [Q3]: $24,947), whereas the postimplant median total cost excluding device acquisition was $398 (Q1: $145, Q3: $1,272) at one month, $2,569 (Q1: $823, Q3: $5,266) at three months, and $5,840 (Q1: $2,160; Q3: $14,607) at six months. The average reduction in total cost was $6,914 (95% CI: $588, $12,458, p < 0.001). The median total acquisition cost was $43,586 (Q1: $29,506, Q3: $69,426), with most coming from outpatient services. Of 88 patients with six-month continuous enrollment, two (2.3%) had device explant.ConclusionsWe present an analysis using large claims data bases of the cost of HF-SCS for treating CRLBP and show that it may be associated with a significant decrease in total health care costs, offsetting device acquisition costs in 27 months. As advances in neuromodulation expand therapy options for patients, it will be important to understand their financial implications.     

The Efficacy of Repeated Radiofrequency Medial Branch Neurotomy for Lumbar Facet Syndrome

Objective

Radiofrequency (RF) medial branch neurotomy is an effective management of lumbar facet syndrome. However, pain may recur after period of time. When pain recurs, it can be repeated, but the successful outcome and duration of relief from repeated procedures are not clearly known. The objective of this study was to determine the success rate and duration of pain relief from repeated radiofrequency medial branch neurotomy for lumbar facet syndrome.

Methods

A retrospective review of medical records was done on 60 consecutive patients, from March of 2006 to February of 2009, who had an initial successful RF neurotomy but subsequently underwent repeated procedures due to recurrence of pain. All procedures were done in carefully selected patients after at least two responsive medial branch nerve blocks. C-arm fluoroscopic guide, impedance, sensory and motor threshold monitoring tools were used for the precise placement of electrodes. Responses of repeated procedures were compared with initial radiofrequency neurotomy for success rates and duration of pain relief.

Results

There were 48 females and 12 males. Mean age was 52.4 years (range, 26-83). RF medial branch neurotomy was done on one side in 38 and both sides in 22 patients, each covering at least three segments. Average visual analog scale at last procedure was 6.8. Twelve patients had previous lumbar operations, including 4 patients with instrumentations. Fifty-five patients had two procedures and five patients had three procedures. Mean duration of successful pain relief (> 50% of previous pain for at least 3 months period) after initial radiofrequency neurotomy was 10.9 months (range, 3-28) in 51 (85%) patients. From repeated procedures, successful pain relief was seen in 50 (91%) patients with average duration of 10.2 months (range, 3-24). Five patients had third procedure, which was successful in 4 (80%) patients with mean duration of 9.8 months (range, 5-16). This was not statistically different from initial results. There were no permanent neurological complications from the procedures.

Conclusion

Results of this study indicate that the frequency of success and durations of relief from repeated RF medial branch neurotomy for lumbar facet syndrome are similar to initial results that provided relatively prolonged period of pain relief without major side effects. Each procedure seems to provide successful pain relief for about 10 months in more than 85% of carefully selected patients when properly done.     

Efficacy of Peripheral Nerve Field Stimulation for the Management of Chronic Low Back Pain and Persistent Spinal Pain Syndrome: A Narrative Review

ObjectivesVarious approaches have been developed with a view to treating the back pain component in patients with chronic low back pain (CLBP) and persistent spinal pain syndrome (PSPS). Emerging evidence shows that peripheral nerve field stimulation (PNFS) may be an efficacious therapeutic modality against axial low back pain. Hence, the aim of the review was to evaluate the analgesic efficacy and safety of PNFS, when used alone or as an adjunct to spinal cord stimulation (SCS), for managing CLBP and PSPS.Materials and MethodsA comprehensive search for clinical studies on PNFS and PNFS + SCS used for the management of CLBP and/or PSPS was performed using PubMed, EMBASE, MEDLINE via Proquest, and Web of Science.ResultsA total of 15 studies were included, of which four were randomized controlled trials (RCTs), nine were observational studies, and two were case series. For patients receiving PNFS, a significant decrease in back pain intensity and analgesic consumption, together with a significant improvement in physical functioning, was observed upon implant of the permanent system. Meanwhile, the addition of PNFS to SCS in refractory cases was associated with a significant reduction in back and leg pain, respectively.ConclusionsThis review suggests that PNFS, when used alone or in combination with SCS, appears to be effective in managing back pain. However, high-quality evidence that supports the long-term analgesic efficacy and safety is still lacking. Hence, RCTs with a larger patient population and of a longer follow-up duration are warranted.     

Three-Year Durability of Restorative Neurostimulation Effectiveness in Patients With Chronic Low Back Pain and Multifidus Muscle Dysfunction

BackgroundRestorative neurostimulation is a rehabilitative treatment for patients with refractory chronic low back pain (CLBP) associated with dysfunction of the lumbar multifidus muscle resulting in impaired neuromuscular control. The ReActiv8-B randomized, sham-controlled trial provided evidence of the effectiveness and safety of an implanted, restorative neurostimulator. The two-year analysis previously published in this journal demonstrated accrual of clinical benefits and long-term durability.ObjectiveEvaluation of three-year effectiveness and safety in patients with refractory, disabling CLBP secondary to multifidus muscle dysfunction and no indications for spine surgery.Materials and MethodsProspective, observational follow-up of the 204 implanted trial participants. Low back pain visual analog scale (VAS), Oswestry Disability Index (ODI), EuroQol quality of life survey, and opioid intake were assessed at baseline, six months, and one, two, and three years after activation. The mixed-effects model repeated measures approach was used to provide implicit imputations of missing data for continuous outcomes and multiple imputation for proportion estimates.ResultsData were collected from 133 participants, and 16 patients missed their three-year follow-up because of coronavirus disease restrictions but remain available for future follow-up. A total of 62% of participants had a ≥ 70% VAS reduction, and 67% reported CLBP resolution (VAS ≤ 2.5cm); 63% had a reduction in ODI of ≥ 20 points; 83% had improvements of ≥ 50% in VAS and/or ≥ 20 points in ODI, and 56% had these substantial improvements in both VAS and ODI. A total of 71% (36/51) participants on opioids at baseline had voluntarily discontinued (49%) or reduced (22%) opioid intake. The attenuation of effectiveness in the imputed (N = 204) analyses was relatively small and did not affect the statistical significance and clinical relevance of these results. The safety profile remains favorable, and no lead migrations have been observed to date.ConclusionAt three years, 83% of participants experienced clinically substantial improvements in pain, disability, or both. The results confirm the long-term effectiveness, durability, and safety of restorative neurostimulation in patients with disabling CLBP associated with multifidus muscle dysfunction.Clinical Trial RegistrationThe Clinicaltrials.gov registration number for the study is NCT02577354.     

The Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection in Peripheral Nerve Field Stimulation for Chronic Low Back Pain: A Prospective Study

ObjectivePeripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. Transcutaneous electrical nerve stimulation (TENS) is frequently used in pain therapy. Aim of this prospective study was to examine the predictive value of TENS for later PNFS treatment.Materials and MethodsBetween 2014 and 2019, a prospective cohort study of 41 patients with chronic lumbar pain was conducted. Pain intensity (NRS) was assessed before and after TENS use, preoperatively/postoperatively and in the follow-up after three and six months, SF12v2 questionnaires with physical (PCS) and mental component summary (MCS) scores, and Oswestry disability index (ODI) questionnaire at baseline as well as three and six months after PNFS implantation. Implantation of the PNFS-system with two percutaneous leads was performed after four to seven days of positive testing. Statistical analysis was performed using depending t-test, ANOVA, and Spearman correlation.ResultsThe cohort consisted of 41 patients (19 females, 22 males) with a median age of 60.5 years (IQR^25-75 52–67). Two patients were lost to follow-up. After positive PNFS testing a pulse generator (IPG) was implanted in 15 patients with positive TENS effect and 15 patients without TENS effect. Leads were explanted in nine patients after negative PNFS trial phase. TENS positive patients showed significant correlation to a positive effect in the PNFS trial phase in NRS reduction (p = 0.042) indicating that TENS responders will also respond to PNFS (94% patients). After three and six months follow-up median NRS and SF12v2 (PCS) improved significantly in both cohorts, SF12v2 (MCS) and ODI only in the TENS positive cohort, respectively.ConclusionTENS can be predictive for patient selection in PNFS, as TENS positive patients showed significant correlation with a positive PNFS trial period. Therefore, TENS positive patients might be justifiable to be directly implanted with leads and IPG. TENS positive patients further tend to show a better improvement in the follow-up.     

Muscle Control and Non‐specific Chronic Low Back Pain

Objectives

Chronic low back pain (CLBP) is the most prevalent of the painful musculoskeletal conditions. CLBP is a heterogeneous condition with many causes and diagnoses, but there are few established therapies with strong evidence of effectiveness (or cost effectiveness). CLBP for which it is not possible to identify any specific cause is often referred to as non‐specific chronic LBP (NSCLBP). One type of NSCLBP is continuing and recurrent primarily nociceptive CLBP due to vertebral joint overload subsequent to functional instability of the lumbar spine. This condition may occur due to disruption of the motor control system to the key stabilizing muscles in the lumbar spine, particularly the lumbar multifidus muscle (MF).

Methods

This review presents the evidence for MF involvement in CLBP, mechanisms of action of disruption of control of the MF, and options for restoring control of the MF as a treatment for NSCLBP.

Results

Imaging assessment of motor control dysfunction of the MF in individual patients is fraught with difficulty. MRI or ultrasound imaging techniques, while reliable, have limited diagnostic or predictive utility. For some patients, restoration of motor control to the MF with specific exercises can be effective, but population results are not persuasive since most patients are unable to voluntarily contract the MF and may be inhibited from doing so due to arthrogenic muscle inhibition.

Conclusions

Targeting MF control with restorative neurostimulation promises a new treatment option.     

Peripheral Nerve Field Stimulation for the Treatment of Chronic Low Back Pain: Preliminary Results of Long‐Term Follow‐up: A Case Series

Objective. Our objective was to determine the efficacy of peripheral nerve field stimulation (PNFS) for the treatment of chronic lower back pain. PNFS is becoming increasingly recognized as a safe, minimally invasive, and easily reversible treatment for a variety of chronic pain conditions. Chronic low back pain is a common cause of disability and one that is difficult to treat effectively. We hypothesized that PNFS would be a safe, effective alternative for patients with chronic low back pain, which has not been previously reported. Materials and Methods. Six patients with chronic low back pain who had failed conventional therapies were implanted in the subcutaneous tissues of the low back region with neurostimulation leads. Leads were placed superficially in the region of maximum pain, as identified by each individual patient. Patients initially underwent a trial of stimulation to assess response, and a permanent system was subsequently implanted if patients reported greater than 50% pain relief in the low back during the trial. Results. In each case presented here, PNFS enabled patients to decrease their pain medication and increase their level of activity. The patients all reported reduction in pain as measured by visual analog scale scores and an improved quality of life. Conclusion. We conclude that PNFS is a safe and effective alternative treatment for patients with chronic low back pain, and should be considered in this population.     

Targeting Chronic Recurrent Low Back Pain From the Top-down and the Bottom-up: A Combined Transcranial Direct Current Stimulation and Peripheral Electrical Stimulation Intervention

BackgroundMechanisms such as neural sensitization and maladaptive cortical organization provide novel targets for therapy in chronic recurrent low back pain (CLBP).ObjectiveWe investigated the effect of a transcranial direct current stimulation (tDCS) and peripheral electrical stimulation (PES) treatment on pain, cortical organization, sensitization and sensory function in CLBP.MethodsUsing a placebo-controlled crossover design, 16 individuals received four treatments in separate sessions: i) anodal tDCS/PES; ii) anodal tDCS/sham PES; iii) sham tDCS/PES; or iv) sham tDCS/sham PES. Pain was assessed at baseline, immediately following, and at 1 and 3 days after treatment. Motor cortical organization, sensitization and sensory function were measured before and immediately after treatment.ResultsCombined tDCS/PES reduced pain and sensitization, normalized motor cortical organization and improved sensory function. The reduction in pain was greater in individuals with more pronounced sensitization. Applied alone, tDCS or PES also reduced pain. However, with the exception of improved sensory function and reduced map volume following PES, clinical and neurophysiological outcomes were unaltered by tDCS or PES applied separately. No changes were observed following sham treatment.ConclusionOur data suggest a combined tDCS/PES intervention more effectively improves CLBP symptoms and mechanisms of cortical organization and sensitization, than either intervention applied alone or a sham control.