Multicolumn spinal cord stimulation for significant low back pain in failed back surgery syndrome: design of a national, multicentre, randomized, controlled health economics trial (ESTIMET Study)

Dorsal root ganglion stimulation for the treatment of chronic pelvic pain: A systematic review

BACKGROUND

Chronic pelvic pain (CPP) is a difficult condition to treat. Due to complex pelvic innervation, dorsal column spinal cord stimulation (SCS) has not been shown to produce the same effect as dorsal root ganglion stimulation (DRGS) given emerging evidence suggesting that applying DRGS may result in favorable outcomes for individuals with CPP. The aim of this systematic review is to investigate the clinical use and effectiveness of DRGS for patients with CPP.

MATERIALS AND METHODS

A systematic review of clinical studies demonstrating the use of DRGS for CPP. Searches were conducted using four electronic databases (PubMed, EMBASE, CINAHL, and Web of Science) across August and September 2022.

RESULTS

A total of nine studies comprising 65 total patients with variable pelvic pain etiologies met the inclusion criteria. The majority of subjects implanted with DRGS reported >50% mean pain reduction at variable times of follow-up. Secondary outcomes reported throughout studies including quality of life (QOL) and pain medication consumption were reported to be significantly improved.

CONCLUSIONS

Dorsal root ganglion stimulation for CPP continues to lack supportive evidence from well-designed, high-quality studies and recommendations from consensus committee experts. However, we present consistent evidence from level IV studies showing success with the use of DRGS for CPP in reducing pain symptoms along with reports of improved QOL through periods as short as 2 months to as long as 3 years. Because the available studies at this time are of low quality with a high risk of bias, we strongly recommend the facilitation of high-quality studies with larger sample sizes in order to better ascertain the utility of DRGS for this specific patient population. At the same time, from a clinical perspective, it may be reasonable and appropriate to evaluate patients for DRGS candidacy on a case-by-case basis, especially those patients who report CPP symptoms that are refractory to noninterventional measures and who may not be ideal candidates for other forms of neuromodulation.

Spinal cord stimulation for low back pain

BACKGROUND

Spinal cord stimulation (SCS) is a surgical intervention used to treat persistent low back pain. SCS is thought to modulate pain by sending electrical signals via implanted electrodes into the spinal cord. The long term benefits and harms of SCS for people with low back pain are uncertain.

OBJECTIVES

To assess the effects, including benefits and harms, of SCS for people with low back pain.

SEARCH METHODS

On 10 June 2022, we searched CENTRAL, MEDLINE, Embase, and one other database for published trials. We also searched three clinical trials registers for ongoing trials.

SELECTION CRITERIA

We included all randomised controlled trials and cross-over trials comparing SCS with placebo or no treatment for low back pain. The primary comparison was SCS versus placebo, at the longest time point measured in the trials. Major outcomes were mean low back pain intensity, function, health-related quality of life, global assessment of efficacy, withdrawals due to adverse events, adverse events, and serious adverse events. Our primary time point was long-term follow-up (≥ 12 months).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 13 studies with 699 participants: 55% of participants were female; mean age ranged from 47 to 59 years; and all participants had chronic low back pain with mean duration of symptoms ranging from five to 12 years. Ten cross-over trials compared SCS with placebo. Three parallel-group trials assessed the addition of SCS to medical management. Most studies were at risk of performance and detection bias from inadequate blinding and selective reporting bias. The placebo-controlled trials had other important biases, including lack of accounting for period and carryover effects. Two of the three parallel trials assessing SCS as an addition to medical management were at risk of attrition bias, and all three had substantial cross-over to the SCS group for time points beyond six months. In the parallel-group trials, we considered the lack of placebo control to be an important source of bias. None of our included studies evaluated the impact of SCS on mean low back pain intensity in the long term (≥ 12 months). The studies most often assessed outcomes in the immediate term (less than one month). At six months, the only available evidence was from a single cross-over trial (50 participants). There was moderate-certainty evidence that SCS probably does not improve back or leg pain, function, or quality of life compared with placebo. Pain was 61 points (on a 0- to 100-point scale, 0 = no pain) at six months with placebo, and 4 points better (8.2 points better to 0.2 points worse) with SCS. Function was 35.4 points (on a 0- to 100-point scale, 0 = no disability or best function) at six months with placebo, and 1.3 points better (3.9 points better to 1.3 points worse) with SCS. Health-related quality of life was 0.44 points out of 1 (0 to 1 index, 0 = worst quality of life) at six months with placebo, and 0.04 points better (0.16 points better to 0.08 points worse) with SCS. In that same study, nine participants (18%) experienced adverse events and four (8%) required revision surgery. Serious adverse events with SCS included infections, neurological damage, and lead migration requiring repeated surgery. We could not provide effect estimates of the relative risks as events were not reported for the placebo period. In parallel trials assessing SCS as an addition to medical management, it is uncertain whether, in the medium or long term, SCS can reduce low back pain, leg pain, or health-related quality of life, or if it increases the number of people reporting a 50% improvement or better, because the certainty of the evidence was very low. Low-certainty evidence suggests that adding SCS to medical management may slightly improve function and slightly reduce opioid use. In the medium term, mean function (0- to 100-point scale; lower is better) was 16.2 points better with the addition of SCS to medical management compared with medical management alone (95% confidence interval (CI) 19.4 points better to 13.0 points better; I2 = 95%; 3 studies, 430 participants; low-certainty evidence). The number of participants reporting opioid medicine use was 15% lower with the addition of SCS to medical management (95% CI 27% lower to 0% lower; I2 = 0%; 2 studies, 290 participants; low-certainty evidence). Adverse events with SCS were poorly reported but included infection and lead migration. One study found that, at 24 months, 13 of 42 people (31%) receiving SCS required revision surgery. It is uncertain to what extent the addition of SCS to medical management increases the risk of withdrawals due to adverse events, adverse events, or serious adverse events, because the certainty of the evidence was very low.

AUTHORS' CONCLUSIONS

Data in this review do not support the use of SCS to manage low back pain outside a clinical trial. Current evidence suggests SCS probably does not have sustained clinical benefits that would outweigh the costs and risks of this surgical intervention.

Combining Awake Anesthesia with Minimal Invasive Surgery Optimizes Intraoperative Surgical Spinal Cord Stimulation Lead Placement

Spinal cord stimulation (SCS) is an effective and validated treatment to address chronic refractory neuropathic pain in persistent spinal pain syndrome-type 2 (PSPS-T2) patients. Surgical SCS lead placement is traditionally performed under general anesthesia due to its invasiveness. In parallel, recent works have suggested that awake anesthesia (AA), consisting of target controlled intra-venous anesthesia (TCIVA), could be an interesting tool to optimize lead anatomical placement using patient intra-operative feedback. We hypothesized that combining AA with minimal invasive surgery (MIS) could improve SCS outcomes. The goal of this study was to evaluate SCS lead performance (defined by the area of pain adequately covered by paraesthesia generated via SCS), using an intraoperative objective quantitative mapping tool, and secondarily, to assess pain relief, functional improvement and change in quality of life with a composite score. We analyzed data from a prospective multicenter study (ESTIMET) to compare the outcomes of 115 patients implanted with MIS under AA (MISAA group) or general anesthesia (MISGA group), or by laminectomy under general anesthesia (LGA group). All in all, awake surgery appears to show significantly better performance than general anesthesia in terms of patient pain coverage (65% vs. 34–62%), pain surface (50–76% vs. 50–61%) and pain intensity (65% vs. 35–40%), as well as improved secondary outcomes (quality of life, functional disability and depression). One step further, our results suggest that MISAA combined with intra-operative hypnosis could potentialize patient intraoperative cooperation and could be proposed as a personalized package offered to PSPS-T2 patients eligible for SCS implantation in highly dedicated neuromodulation centers.

Comparison of Spinal Cord Stimulation vs. Dorsal Root Ganglion Stimulation vs. Association of Both in Patients with Refractory Chronic Back and/or Lower Limb Neuropathic Pain: An International, Prospective, Randomized, Double-Blinded, Crossover Trial (BOOST-DRG Study)

While spinal cord stimulation (SCS) is a well-established therapy to address refractory persistent spinal pain syndrome after spinal surgery (PSPS-T2), its lack of spatial selectivity and reported discomfort due to positional effects can be considered as significant limitations. As alternatives, new waveforms, such as burst stimulation and different spatial neural targets, such as dorsal root ganglion stimulation (DRGS), have shown promising results. Comparisons between DRGS and standard SCS, or their combination, have never been studied on the same patients. "BOOST DRG" is the first prospective, randomized, double-blinded, crossover study to compare SCS vs. DRGS vs. SCS+DRGS. Sixty-six PSPS-T2 patients will be recruited internationally in three centers. Before crossing over, patients will receive each stimulation modality for 1 month, using tonic conventional stimulation. After 3 months, stimulation will consist in switching to burst for 1 month, and patients will choose which modality/waveform they receive and will then be reassessed at 6 and 12 months. In addition to our primary outcome based on pain rating, this study is designed to assess quality of life, functional disability, psychological distress, pain surface coverage, global impression of change, medication quantification, adverse events, brain functional imaging and electroencephalography, with the objective being to provide a multidimensional insight based on composite pain assessment.

A Systematic Review of the Cost-Utility of Spinal Cord Stimulation for Persistent Low Back Pain in Patients With Failed Back Surgery Syndrome

STUDY DESIGN

Systematic Review.

OBJECTIVES

To review the literature surrounding the cost-effectiveness of implanting spinal cord stimulators for failed back surgery syndrome.

METHODS

A systematic review was conducted inclusive of all publications in the Medline database and Cochrane CENTRAL trials register within the last 10 years (English language only) assessing the cost-effectiveness of Spinal Cord Stimulator device implantation (SCSdi) in patients with previous lumbar fusion surgery.

RESULTS

The majority of reviewed publications that analyzed cost-effectiveness of SCSdi compared to conventional medical management (CMM) or re-operation in patients with failed back surgery syndrome (FBSS) showed an overall increase in direct medical costs; these increased costs were found in nearly all cases to be offset by significant improvements in patient quality of life. The cost required to achieve these increases in quality adjusted life years (QALY) falls well below $25 000/QALY, a conservative estimate of willingness to pay.

CONCLUSIONS

The data suggest that SCSdi provides both superior outcomes and a lower incremental cost: effectiveness ratio (ICER) compared to CMM and/or re-operation in patients with FBSS. These findings are in spite of the fact that the majority of studies reviewed were agnostic to the type of device or innervation utilized in SCSdi. Newer devices utilizing burst or higher frequency stimulation have demonstrated their superiority over traditional SCSdi via randomized clinical trials and may provide lower ICERs.

Utility of Electrical Neuromodulation for Treating Chronic Pain Syndromes in the Pediatric Setting: A Systematic Review

OBJECTIVES

Chronic pain syndromes in children can carry significant threats to psychological well-being, opioid overuse, functional impairments, and severe disability. While several high-level studies, almost exclusively in adults, have demonstrated the utility of implantable electrical neuromodulation systems for treating various chronic pain syndromes, there exists a paucity of pediatric-specific evidence. Unfortunately, evidence and practice patterns established from adults may not be fully translatable to children given differences in disease manifestations and anatomical variances.

MATERIALS AND METHODS

We performed a systematic review using conventional PRISMA methodology to identify studies reporting use of implantable electrical neuromodulation systems in children. The primary outcome parameters collected were analgesic relief and functional benefits. Additionally, previous interventions attempted, neuromodulation parameters, and limitations were collected as reported.

RESULTS

A total of 11 studies was identified, which described 19 patients who were refractory to multidisciplinary pain management strategies. The cohort was mostly adolescent (18/19), suffered from CRPS (14/19), and received SCS (17/19). Nearly all patients, both those with CRPS (13/14) and non-CRPS conditions (4/4), reported significant pain relief and functional recovery following neuromodulation. There were no severe complications reported; limitations included suboptimal benefit or loss of analgesia (3/19), lead or device revision (3/19), and subcutaneous infection (1/19), all of which were congruent with adult outcomes.

CONCLUSION

There exist children with chronic pain refractory to standard of care approaches who could be considered for neuromodulation interventions. The existing data, which was limited and from a low tier of evidence, suggest that these interventions are relatively safe and provide meaningful pain reduction and functional improvements. While not previously reported, we recommend careful consideration of the pubertal growth spurt prior to device lead placement-if reasonable and appropriate-given the possibility of inferior lead migration with physiologic growth in patients with SCS devices or foraminal extrusion in patients with dorsal root ganglion stimulation devices.

Dorsal Root Ganglion Stimulation for the Treatment of Non-Complex Regional Pain Syndrome Related Chronic Pain Syndromes: A Systematic Review

BACKGROUND

While the majority of indications and approvals for dorsal root ganglion stimulation (DRGS) are for the refractory management of complex regional pain syndrome (CRPS), emerging evidence has suggested that DRGS may be favorably used for a plethora of other chronic pain phenomena. Consequently, we aimed to characterize the use and efficacy of DRGS for these non-CRPS-related chronic pain syndromes.

MATERIALS AND METHODS

A systematic review of clinical studies demonstrating the use of DRGS for non-CRPS-related chronic pain syndromes. The literature search was performed using PubMed, Cochrane Library, and CINAHL plus across August and September 2020.

RESULTS

A total of 28 reports comprising 354 total patients were included in the analysis. Of the chronic pain syndromes presented, axial low back pain, chronic pelvic and groin pain, other peripheral neuropathies, and studies with multiple concomitant pain syndromes, a majority demonstrated >50% mean pain reduction at the time of last follow-up following DRGS. Physical function, quality of life (QOL), and lesser pain medication usage also were repeatedly reported to be significantly improved.

CONCLUSIONS

DRGS continues to lack supportive evidence from well designed, high level studies and recommendations from consensus committee experts. However, we present repeated and consistent evidence from lower level studies showing success with the use of DRGS for various non-CRPS chronic pain syndromes in reducing pain along with increasing function and QOL from one week to three years. Due to such low-level, high bias evidence, we strongly encourage the continuation of high-level studies in order to provide a stronger foundation for the use of DRGS in non-CRPS chronic pain patients. However, it may be reasonable and appropriate to evaluate patients for DRGS candidacy on a case-by-case basis particularly if they manifest focal pain syndromes refractory to noninterventional measures and may not be ideal candidates for other forms of neuromodulation.

High-frequency spinal cord stimulation treatment attenuates the increase in spinal glutamate release and spinal miniature excitatory postsynaptic currents in rats with spared nerve injury-induced neuropathic pain

High-frequency spinal cord stimulation (HFSCS) at 10 kHz provides paresthesia-free treatment for chronic pain. However, the underlying mechanisms of its action have not been fully elucidated. The aim of the present study was to investigate the effect of HFSCS treatment on spinal glutamate release and uptake in spared nerve injury (SNI) rats. HFSCS was applied to the T10/T11 spinal cord 3 days after SNI. The concentration of spinal glutamate, glutamate transporter activity and miniature excitatory postsynaptic currents (mEPSCs) from neurons in lamina II were evaluated. HFSCS treatment alleviated SNI pain induced by mechanical and cold allodynia. HFSCS treatment also partially restored altered spinal glutamate uptake activity, the levels of spinal glutamate, and the frequency of mEPSCs following SNI. In conclusion, HFSCS treatment attenuated SNI-induced neuropathic pain and partially restored the altered glutamate uptake after SNI.

How Should we Use Multicolumn Spinal Cord Stimulation to Optimize Back Pain Spatial Neural Targeting? A Prospective, Multicenter, Randomized, Double-Blind, Controlled Trial (ESTIMET Study)

BACKGROUND

Recent studies have highlighted multicolumn spinal cord stimulation (SCS) efficacy, hypothesizing that optimized spatial neural targeting provided by new-generation SCS lead design or its multicolumn programming abilities could represent an opportunity to better address chronic back pain (BP).

OBJECTIVE

To compare multicolumn vs. monocolumn programming on clinical outcomes of refractory postoperative chronic BP patients implanted with SCS using multicolumn surgical lead.

MATERIALS AND METHODS

Twelve centers included 115 patients in a multicenter, randomized, double-blind, controlled trial. After randomization, leads were programmed using only one or several columns. The primary outcome was change in BP visual analogic scale (VAS) at six months. All patients were then programmed using the full potential of the lead up until 12-months follow-up.

RESULTS

At six months, there was no significant difference in clinical outcomes whether the SCS was programmed using a mono or a multicolumn program. At 12 months, in all patients having been receiving multicolumn SCS for at least six months (n = 97), VAS decreases were significant for global pain (45.1%), leg pain (55.8%), and BP (41.5%) compared with baseline (p < 0.0001).

CONCLUSION

The ESTIMET study confirms the significant benefit experienced on chronic BP by patients implanted with multicolumn SCS, independently from multicolumn lead programming. These good clinical outcomes might result from the specific architecture of the multicolumn lead, giving the opportunity to select initially the best column on a multicolumn grid and to optimize neural targeting with low-energy requirements. However, involving more columns than one does not appear necessary, once initial spatial targeting of the "sweet spot" has been achieved. Our findings suggest that this spatial concept could also be transposed to cylindrical leads, which have drastically improved their capability to shape the electrical field, and might be combined with temporal resolution using SCS new modalities.

A multi-center, randomized controlled clinical trial, cost-effectiveness and qualitative research of electroacupuncture with usual care for patients with non-acute pain after back surgery: study protocol for a randomized controlled trial

BACKGROUND

Although pain after back surgery is known to be difficult to control, various treatment options are available to patients and physicians. A protocol for a confirmatory randomized controlled trial (RCT) on pain and function after back surgery was designed based on the results of a pilot trial. The aim of this study is to compare the effectiveness and safety of electroacupuncture (EA) with usual care (UC) versus UC alone on pain control and functional improvement after back surgery.

METHODS/DESIGN

This study is a multi-center, randomized, assessor-blinded trial with an active control conducted in conjunction with a cost-effectiveness analysis and qualitative research. Participants with non-acute low back pain with or without leg pain after back surgery who have a Visual Analogue Scale (VAS) pain intensity score ≥ 50 mm will be randomly assigned to either the EA with UC group (n = 54) or the UC group (n = 54). Following randomization, participants in both groups will receive the same UC treatment twice a week for a four-week treatment period. Participants assigned to the EA with UC group will additionally receive EA twice a week for the same four-week period. The primary outcome measure will be assessed using a VAS pain intensity score for low back pain. The secondary outcomes will include the Oswestry Disability Index, EuroQol 5-Dimension score, and drug intake. The primary and secondary outcomes will be measured at one, four, and eight weeks post randomization.

DISCUSSION

The results of this study will provide evidence of the effectiveness and cost-effectiveness of EA in managing postoperative pain following back surgery. In addition, the qualitative research results will help improve the quality of integrative medical interventions.

TRIAL REGISTRATION

Clinical Research Information Service (CRIS), Republic of Korea, KCT0001939 . Registered on 8 June 2016.

Neuropathic Pain after Spinal Surgery

Neuropathic pain after spinal surgery, the so-called failed back surgery syndrome (FBSS), is a frequently observed troublesome disease entity. Although medications may be effective to some degree, many patients continue experiencing intolerable pain and functional disability. Only gabapentin has been proven effective in patients with FBSS. No relevant studies regarding manipulation or physiotherapy for FBSS have been published. Spinal cord stimulation (SCS) has been widely investigated as a treatment option for chronic neuropathic pain, including FBSS. SCS was generally accepted to improve chronic back and leg pain, physical function, and sleep quality. Although the cost effectiveness of SCS has been proved in many studies, its routine application is limited considering that it is invasive and is associated with safety issues. Percutaneous epidural adhesiolysis has also shown good clinical outcomes; however, its effects persisted for only a short period. Because none of the current methods provide absolute superiority in terms of clinical outcomes, a multidisciplinary approach is required to manage this complex disease. Further studies concerning the etiology, diagnosis, treatment, and cost effectiveness of FBSS are warranted to deepen our understanding of this condition.

A review of spinal cord stimulation systems for chronic pain

Spinal cord stimulation (SCS) applications and technologies are fast advancing. New SCS technologies are being used increasingly in the clinical environment, but often there is a lag period between the clinical application and the publishing of high-quality evidence on safety and efficacy. Recent developments will undoubtedly expand the applicability of SCS, allowing more effective and individualized treatment for patients, and may have the potential to salvage patients who have previously failed neuromodulation. Already, high-level evidence exists for the safety, efficacy, and cost-effectiveness (Level I–II) of traditional SCS therapies in the treatment of chronic refractory low back with predominant limb pain (regardless of surgical history). More than half of all patients with chronic painful conditions experience sustained and significant levels of pain reduction following SCS treatment. Although only limited evidence exists for burst stimulation, there is now Level I evidence for both dorsal root ganglion SCS and high-frequency SCS that demonstrates compelling results compared with traditional therapies. The body of evidence built on traditional SCS research may be redundant, with newer iterations of SCS therapies such as dorsal root ganglion SCS, high-frequency SCS, and burst SCS. A number of variables have been identified that can affect SCS efficacy: implanter experience, appropriate patient selection, etiologies of patient pain, existence of comorbidities, including psychiatric illness, smoking status, and delay to SCS implant following pain onset. Overall, scientific literature demonstrates SCS to be a safe, effective, and drug-free treatment option for many chronic pain etiologies.

"MAST" prospective study: value of minimal access spine technologies technique for multicolumn spinal cord stimulation surgical lead implantation in the context of a French multicentre randomized controlled trial (ESTIMET study)

BACKGROUND AND PURPOSE

Spinal cord stimulation (SCS) has been demonstrated to be an effective treatment for postoperative persistent leg pain after spine surgery, but treatment of the back pain component remains much more difficult, as it comprises mixed neuropathic and mechanical pain mechanisms. Moreover, these patients could present damaged tissues at the site of SCS lead implantation as a result of previous spine surgery. It can therefore be logically assumed that minimizing the surgical invasiveness of SCS implantation would be beneficial for these patients. Several studies have demonstrated the value of Minimal Access Spine Technologies (MAST) in spine surgery, but only a few case reports have been published concerning the use of MAST techniques for SCS. Therefore, we were prompted to conduct a second ESTIMET ancillary study to prospectively analyse the potential impact and benefits of MAST technique during SCS lead implantation versus an open surgical approach.

METHODS

This is a multicentre, comparative, ancillary study conducted in 61 patients among the 115 enrolled patients ESTIMET study. One arm comprises patients undergoing multicolumn lead implantation via a Conventional Open Approach (COA) and the other arm comprises patients implanted by a MAST approach. Patients will be followed for 12 months after lead implantation. The following data will be collected: elevation of muscle enzymes (serum CPK), scar size, blood loss, infection rate, operating time and global, leg, back and scar NPRS.

TRIAL STATUS

The first patient of this ancillary study was enrolled on 21 May 2012 and recruitment has now been achieved. Primary endpoint findings are expected to be available in 2015.

CONCLUSION

Minimally invasive techniques have now been used for spine surgery for the past 12 years, and could also be useful in the context of SCS lead implantation, especially in patients with chronic back pain prior to implantation.