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.     

Subcutaneous Stimulation as Add-on Therapy to Spinal Cord Stimulation in Patients With Persistent Spinal Pain Syndrome Significantly Increases the Total Electrical Charge per Second: Aspects on Stimulation Parameters and Energy Requirements of the Implanted Neurostimulators

ObjectiveIn our previous multicenter randomized controlled trial, we demonstrated the clinical effectiveness of peripheral nerve field stimulation (PNFS) as add-on therapy to spinal cord stimulation (SCS) for the treatment of chronic back pain in patients with persistent spinal pain syndrome (PSPS) or failed back surgery syndrome (FBSS). To our knowledge, no previous study has investigated the effect of PNFS as an add-on to SCS on the energy consumption of the implanted neurostimulators. Therefore, in this study, we compared the specific stimulation parameters and energy requirements of a previously unreported group of patients with only SCS with those of a group of patients with SCS and add-on PNFS. We also investigated differences that might explain the need for PNFS in the treatment of chronic low back pain.Materials and MethodsWe analyzed 75 patients with complete sets of stimulation parameters, with 21 patients in the SCS-only group and 54 patients in the SCS + PNFS group. Outcome measures were average visual analog scale score, SCS parameters (voltage, frequency, and pulse width), SCS charge per second, and total charge per second. We analyzed baseline characteristics and differences between and within groups over time.ResultsBoth groups had comparable patient characteristics at baseline and showed a significant decrease in back and leg pain. SCS charge per second did not significantly differ between the groups at baseline or at 12 months. The total charge per second was significantly higher in the active SCS + PNFS group than in the SCS-only group at baseline; in the SCS + PNFS group, this persisted for up to 12 months, and the SCS charge per second and total charge per second increased significantly over time.ConclusionsOur results show that add-on PNFS increases the total charge per second compared with SCS alone, as expected. However, further research is needed because our results do not directly explain why some patients require add-on PNFS to treat low back pain.     

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.     

Prospective,Two-part Study of the Interaction Between Spinal Cord Stimulation and Peripheral Nerve Field Stimulation in Patients with Low Back Pain: Development of a New Spinal-Peripheral Neurostimulation Method

Objective: The goal of the study was to assess the efficacy of interaction between spinal cord stimulation (SCS) and peripheral nerve field stimulation (PNFS) and to evaluate a new spinal‐peripheral neuromodulation method for low back pain. Materials and Methods: The prospective two‐part study included patients with low back pain due to failed back surgery syndrome and/or spinal stenosis. In the first part 20 patients were implanted with SCS and PNFS. They selected the best program out of three: SCS alone, PNFS alone, or both together. In the second part another 20 patients with the same implanted leads were selecting between three programs: SCS and PNFS separately, SCS as anode and PNFS as cathode, or in reverse. Results: In the first part 79% of the patients selected simultaneous use of SCS and PNFS. The overall success of the trials was 85%. In the second part communication between SCS and PNFS provided wider coverage of axial pain. The overall success of the trials was 90%. Conclusion: Simultaneous use of SCS and PNFS increase efficacy of both methods for axial back pain. The new SPN method showed great potential in providing coverage for back pain.     

Peripheral Nerve Field Stimulation in the Treatment of Postlaminectomy Syndrome after Multilevel Spinal Surgeries

Introduction: Chronic low back pain in patients with postlaminectomy syndrome (PLS) is challenging to treat, especially for patients who have undergone multilevel surgical procedures. Despite conservative therapy and available interventional pain procedures including spinal cord stimulation (SCS) and intrathecal therapies, patients may continue with intractable low back pain. Peripheral nerve field stimulation (PNFS) may represent an effective alternative treatment option for these patients when conventional treatments do not provide adequate relief of intractable low back pain. Methods: Eighteen patients underwent an uneventful PNFS trial with percutaneous placement of four temporary quadripolar leads (Medtronic, Inc., Minneapolis, MN, USA) placed subcutaneously over the lumbar or thoraco‐lumbar area. Results: After experiencing excellent pain relief over the next two days, temporary leads were removed. The patients were implanted with permanent leads and rechargeable or non‐rechargeable generator two to four weeks after temporary lead removal. All patients reported sustained pain relief 12 months after implantation. Discussion: PNFS with use of four vertically orientated leads provides an effective treatment option for patients with PLS after multilevel surgical procedures with intractable low back pain who have failed conservative treatment. PNFS may provide pain relief with advantages over conservative treatments and interventional treatments including SCS and intrathecal therapy. Conclusion: PNFS may be more effective in treating intractable low back pain than SCS in patients with PLS after multilevel spinal surgeries.     

Subcutaneous Stimulation as an Additional Therapy to Spinal Cord Stimulation for the Treatment of Lower Limb Pain and/or Back Pain: A Feasibility Study

Objective: The objective of this study was to demonstrate the efficacy of subcutaneous stimulation (SubQ) as an additional therapy in patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) was unsuccessful in treating low back pain. Study Design: Case series. Materials and Methods: FBSS patients with chronic limb and/or low back pain whose conventional therapies had failed received a combination of SCS (8‐contact Octad lead) and/or SubQ (4‐contact Quad Plus lead(s)). Initially leads were placed in the epidural space for SCS for a trial stimulation to assess response to suppression of limb and low back pain. Where SCS alone was insufficient in treating lower back pain, leads were placed superficially in the subcutaneous tissue of the lower back, directly in the middle of the pain area. A pulse generator was implanted if patients reported more than 50% pain relief during the trial period. Pain intensity for limb and lower back pain was scored separately, using visual analog scale (VAS). Pain and Quebec Back Pain Disability Scale (QBPDS) after 12‐month treatment were compared with pain and QBPDS at baseline. Results: Eleven FBSS patients, five male and six female (age: 51 ± 8 years; mean ± SD), in whom SCS alone was insufficient in treating lower back pain, were included. In nine cases, SubQ was used in combination with SCS to treat chronic lower back and lower extremity pain. In two cases only SubQ was used to treat lower back pain. SCS significantly reduced limb pain after 12 months (VAS_bl: 62 ± 14 vs. VAS_12m: 20 ± 11; p= 0.001, N= 8). SubQ stimulation significantly reduced low back pain after 12 months (VAS_bl: 62 ± 13.0 vs. VAS_12m: 32 ± 16; p= 0.0002, N= 10). Overall pain medication was reduced by more than 70%. QBPDS improved from 61 ± 15 to 49 ± 12 (p= 0.046, N= 10). Furthermore, we observed that two patients returned to work. Conclusion: SubQ may be an effective additional treatment for chronic low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms.     

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.     

Combined Spinal Cord and Peripheral Nerve Field Stimulation for Persistent Post‐Herniorrhaphy Pain

Objectives: Chronic post‐hernia pain is a common complication after inguinal herniorrhaphies. Peripheral nerve field stimulation (PNFS) and spinal cord stimulation (SCS) are two new promising treatment modalities. Four patients with persistent neuropathic post‐hernia pain were recruited for this prospective study. Materials and Methods: Electrodes were inserted into the epidural space of the spinal canal and into the subcutaneous tissue in the inguinal region during a single surgical procedure. During a 14‐day trial, double‐blind stimulation was performed via an external stimulator: three days using the spinal electrode (SCS), three days using the inguinal electrode (PNFS), three days using both (SCS + PNFS), and five days off, with an alternating order from patient to patient. During the trial, pain intensity was assessed thrice daily by the visual analog scale. Additionally, pain intensity and quality of life (QOL) were assessed before and after surgical intervention by the Brief Pain Inventory, SF36 scale, and Pain Disability Index. Results: All patients had a marked pain reduction during the trial phase, and this reduction was more prominent when both electrodes were activated simultaneously (p < 0.001). At the late follow‐up, a significant pain reduction and improvement of QOL was observed in three patients. Conclusions: Both SCS and PNFS are effective in treating post‐hernia pain, but the magnitude of pain reduction was more prominent with concomitant stimulation. Combined PNFS and SCS should be considered for patients with a less than optimal response to either SCS or PNFS. More studies are necessary to address the cost‐effect issues of this new approach to treatment.     

Spinal Cord Stimulation With Hybrid Lead Relieves Pain in Low Back and Legs

Objective: The failed back surgery syndrome (FBSS) is the most common chronic pain syndrome. Whereas it is relatively easy to achieve pain relief in the lower limbs of FBSS patients with spinal cord stimulation (SCS), it is difficult to manage low back pain with SCS. The performance of a paddle‐shaped SCS lead that can be inserted surgically as well as percutaneously (a hybrid lead) was evaluated in a prospective study on the relief of low back pain and leg pain in patients with FBSS. Materials and Methods: Patients with FBSS being eligible for SCS were enrolled in the study, and a hybrid lead was placed surgically. Outcome measures included pain scores for low back and leg pain assessed by visual analog scale (VAS), pain medication, and patient satisfaction. These scores were assessed before and at regular intervals after implantation. Results: It was shown that a single hybrid lead, generally positioned over the physiological midline of the spinal cord, is capable of alleviating both low back and leg pain in patients with FBSS. Forty‐five subjects were eligible for SCS and received trial stimulation. Forty‐two of them had a successful trial period and were converted to a permanent system. Their average VAS score at baseline was 8.0 for lower limb pain and 7.5 for low back pain. After six months of SCS, these average VAS scores were reduced to 3.2 and 3.5, respectively, and also pain medication was reduced significantly. Conclusion: SCS with a hybrid lead in subjects with FBSS is safe, and causes significant pain relief in both the low back and the lower limbs.     

Spinal Cord Stimulation vs. Conventional Medical Management: A Prospective,Randomized, Controlled,Multicenter Study of Patients with Failed Back Surgery Syndrome (PROCESS Study)

Introduction. Since its first application in 1967, numerous case series indicate that spinal cord stimulation (SCS) is an effective treatment for the management of failed back surgery syndrome (FBSS). However, only one randomized controlled trial has demonstrated that SCS provides more effective pain relief than re‐operation and conventional medical management. The PROCESS randomized, controlled, multicenter trial aims to assess the clinical effectiveness and cost‐effectiveness of SCS when added to conventional medical management compared to conventional medical management alone in patients with FBSS. Methods/Design. A total of 100 FBSS patients with predominantly neuropathic leg pain will be recruited from 12 centers and randomized to receive either conventional medical management alone or in combination with SCS for a period of 24 months. Patients will be evaluated at 1, 3, 6, 9, 12, 18, and 24 months. At the 6‐month visit, patients will be classified as successful (≥  50% pain relief in the legs) or unsuccessful (< 50% pain relief in the legs). If the results of the randomized treatment are unsuccessful, patients can cross over to the alternative treatment arm. Discussion. This paper highlights the rationale, design, methods, and challenges of an ongoing prospective, randomized, controlled, multicenter clinical trial that has been undertaken to obtain conclusive evidence of the clinical efficacy and cost‐effectiveness of an SCS system in patients with FBSS.     

Spinal Cord Stimulation Has Comparable Efficacy in Common Pain Etiologies

Objectives. The probability of success with spinal cord stimulation (SCS) depends largely on appropriate patient selection. Here, we have assessed the predictive value of pain etiology as it relates to pain relief with SCS as part of a prospective multicenter clinical trial. Methods. Sixty‐five subjects with chronic and intractable pain tested an epidural SCS system. Subjects reported pain ratings (visual analog scale) with stimulation off and stimulation on at scheduled follow‐up visits for up to 18 months after activation of the system. Visual analog scale scores were averaged and stratified by dominant pain etiologies, comprising failed back surgery syndrome, complex regional pain syndrome, and a subgroup of subjects with miscellaneous other pain etiologies. Results. More than 70% of subjects in each subgroup had successful outcomes during the temporary trial period and similar percentages of subjects from each etiology subgroup subsequently went on to permanent implantation. After permanent implantation, all subgroups reported more than 50% pain relief, on average, at each follow‐up time point. No predictive value of pain etiology was observed. Conclusions. Spinal cord stimulation is an effective therapy for neuropathic pain arising from a variety of causes. Failed back surgery syndrome, complex regional pain syndrome, and pain of other etiologies responded equally well to SCS.     

A Unique Approach to Neurostimulation in Patients With Previous Two‐Segment Spine Surgery and Obstruction of Epidural Access for Spinal Cord Stimulation: A Case Series

Introduction: Patients with extensive surgery in the lumbar and thoracic spine are often not considered for neurostimulation due to the inability to perform a conventional spinal cord stimulation (SCS) trial. We are presenting six such patients in which spinal‐peripheral neurostimulation (SPN) was used via a caudal approach. Methods: Six patients with intractable low back and leg pain following extensive lumbar and thoracic surgeries, up to at least the T10 level, underwent a stimulation trial with one caudal lead and one subcutaneous lead in order to achieve SPN. Results: In five cases, the trial was successful with coverage of the pain area and at least satisfactory pain relief. All six patients were implanted with a paddle lead(s) and a subcutaneous lead using SPN with good pain control. Conclusion: SPN with a caudal lead appears to be a viable option for SCS trial in patients with no possibilities for conventional trial lead placement.     

Spinal Cord Stimulation for Failed Back Surgery Syndrome

Objective. The purpose of this study is to evaluate the effectiveness of modern spinal cord stimulation (SCS) for the treatment of failed back surgery syndrome (FBSS). Materials and Methods. Thirty patients were treated with SCS between December 1992 and January 1998 for low back and radicular pain after multiple failed back surgeries. Permanent systems were implanted if trial stimulation led to > 50% pain reduction. Median long‐term follow‐up was 34 months (range, 6–66 months). Severity of pain was determined postoperatively by a disinterested third party. Results. Overall, 12 of the 16 patients (75%) who received permanent implants continued to report at least 50% relief of pain at follow‐up. All six patients who underwent placement of laminectomy‐styled electrode for SCS in the thoracic region had > 50% pain relief at long‐term follow‐up. Visual analog scores decreased an average of 3.2 (from 8.6 preoperatively to 5.4 postoperatively). Patients undergoing SCS placement via laminectomy in the thoracic region experienced an average decrease of 4.9 in VAS, whereas those who underwent percutaneous placement of thoracic leads had an average decrease of 2.5. Conclusions. SCS is an effective treatment for chronic low back and lower extremity pain which is refractory to conservative therapy and which is not amenable to corrective anatomic surgery. Though our patient population is small, our results imply that the laminectomy‐style electrodes in the thoracic region achieve better long‐term effectiveness than percutaneous leads.     

Triangular Stimulation Method Utilizing Combination Spinal Cord Stimulation With Peripheral Subcutaneous Field Stimulation for Chronic Pain Patients: A Retrospective Study

Objectives: This retrospective data collection study aims to evaluate the responses of patients who have been implanted with a neuromodulation system using a combination of spinal cord stimulation (SCS) and peripheral subcutaneous field stimulation (PSFS) leads for chronic intractable pain. Materials and Methods: Forty patients with chronic, intractable pain implanted with both SCS and PSFS leads were enrolled in a retrospective data collection study. Pre‐implant data (demographics, pain levels, pain location, and medication use) and post‐implant data (pain levels, medication use, and device programming reports) were compared to measure short‐ and long‐term improvements in pain for a period of approximately six months. Device system use and parameter data were collected. Results: The majority of patients experienced immediate and short‐term pain relief and reduction in oral pain medications as a result of combination SCS/PSFS therapy. The improvements were maintained for some, but not all patients by six months. Patients cycled through multiple programs over follow‐up; the use of triangular stimulation was consistent over time, and by six months, patients preferred this program over others. Limitations of the retrospective chart review included missing data and variable follow‐up times, and may have made determinations of long‐term efficacy difficult. Conclusions: This study demonstrates that combination SCS and PSFS therapy is potentially a beneficial treatment option for reducing pain levels and oral pain medication compared with baseline in previously resistive chronic pain patients. There is a need for further study of this therapy in a greater number of subjects and in a prospective, controlled setting. In the author's general experience, triangular stimulation is very effective for treating isolated low back pain, because it covers larger topographic areas of the lower back than flow or field stimulation. An investigational device exemption study will be necessary for subcutaneous field stimulation indicated for focal isolated pain to be adequately investigated and utilized by physicians in the future.     

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.     

Treatment of Multifocal Pain with Spinal Cord Stimulation

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

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.     

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.     

Epidural Spinal Cord Stimulation with a Multiple Electrode Paddle Lead Is Effective in Treating Intractable Low Back Pain

The objective of this paper is to examine the outcomes of patients with intractable low‐back pain treated with epidural spinal cord stimulation (SCS) utilizing paddle electrodes and a radio frequency (RF) stimulator. A multicenter prospective study was performed to collect data from patients suffering from chronic low‐back pain. The study was designed to collect data from 60 patients at four centers and examine their outcomes at, or up to two years post implantation. Patients' participation included written responses to a series of preoperative questionnaires that were designed to collect previous surgical history information, leg and low back pain characteristics, and routine demographic information. Outcome measurements included the visual analog scale (VAS), the Oswestry Disability Questionnaire, the Sickness Impact Profile (SIP), and a patient satisfaction rating scale. Data were collected at each site during patient visits or by mail, at approximately six months, 12 months, and 24 months. A total of 44 patients have been implanted with a SCS system at the time of this writing. Follow‐up data were available for 41 patients. Preoperatively, all patients reported more than 50% of their pain in the low back. All patients had pain in both their backs and legs. All patients showed a reported mean decrease in their 10‐point VAS scores compared to baseline. The majority of patients reported fair to excellent pain relief in both the low back and legs. At six months 91.6% of the patients reported fair to excellent relief in the legs and 82.7% of the patients reported fair to excellent relief in the low back. At one year 88.2% of the patients reported fair to excellent relief in the legs and 68.8% of the patients reported fair to excellent relief in the low back. Significant improvement in function and quality of life was found at both the six‐month and one‐year follow‐ups using the Oswestry and SIP, respectively. The majority of patients reported that the procedure was worthwhile (92% at six months, 88% at one year). No patient indicated that the procedure was not worthwhile. We conclude that SCS proved beneficial at one year for the treatment of patients with chronic low back and leg pain.     

Spinal Cord Stimulation Versus Re-operation in Patients With Failed Back Surgery Syndrome: An International Multicenter Randomized Controlled Trial (EVIDENCE Study)

Objective: This paper presents the protocol of the EVIDENCE study, a multicenter multinational randomized controlled trial to assess the effectiveness and cost‐effectiveness of spinal cord stimulation (SCS) with rechargeable pulse generator versus re‐operation through 36‐month follow‐up in patients with failed back surgery syndrome. Study Design: Study subjects have neuropathic radicular leg pain exceeding or equaling any low back pain and meet specified entry criteria. One‐to‐one randomization is stratified by site and by one or more prior lumbosacral operations. The sample size of 132 subjects may be adjusted to between 100 and 200 subjects using a standard adaptive design statistical method with pre‐defined rules. Crossover treatment is possible. Co‐primary endpoints are proportion of subjects reporting ≥50% leg pain relief without crossover at 6 and at 24 months after SCS screening trial or re‐operation. Insufficient pain relief constitutes failure of randomized treatment, as does crossover. Secondary endpoints include cost‐effectiveness; relief of leg, back, and overall pain; change in disability and quality of life; and rate of crossover. We are collecting data on subject global impression of change, patient satisfaction with treatment, employment status, pain/paresthesia overlap, SCS programming, and adverse events. Discussion: As the first multicenter randomized controlled trial of SCS versus re‐operation and the first to use only rechargeable SCS pulse generators, the EVIDENCE study will provide up‐to‐date evidence on the treatment of failed back surgery syndrome.