Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain

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

OBJECTIVES

Neuromodulation is an effective treatment for chronic pain; however, socioeconomic differences may influence decision-making to initiate this therapy. This review investigated potential differences in accessibility of neuromodulation for patients with chronic pain due to socioeconomic determinants.

MATERIALS AND METHODS

Four electronic databases were used for this systematic review: MEDLINE, Embase, Scopus, and Web of Science. Risk of bias was assessed using the modified version of the Downs and Black checklist. The study protocol was prospectively registered on PROSPERO (CRD42023426035).

RESULTS

The initial database search identified a total of 1118 unique studies, of which 36 were eventually included in the systematic review. Of the 36 included studies, six studies reported on education, 24 on employment status, ten on insurance, five on household income, and three on miscellaneous topics. Neuromodulation seems accessible for patients with different education levels and different types of insurance. Additionally, it is not restricted to patients who are (un)employed. When comparing patients who initiated neuromodulation with those who did not, a significantly higher number of patients in the top quartile for education were found in the group without neuromodulation. Regarding insurance, inconclusive evidence was found.

CONCLUSIONS

Although neuromodulation was accessible for patients with varying levels of socioeconomic determinants, disparities were noted. When comparing the socioeconomic profiles of patients who receive neuromodulation and those who do not, education levels differ. Health-related inequality should be carefully monitored in chronic pain management with neuromodulation to ensure that potential disparities do not increase.

Smaller thoracic canal diameters are associated with thoracic radiculopathy and abdominal pain after spinal cord stimulator paddle lead placement

INTRODUCTION

It is not uncommon for patients to experience postoperative neurologic deficit, thoracic radiculopathy, abdominal pain, or lower extremity paresthesia after the implantation of thoracic spinal cord stimulator (SCS) paddle leads. Smaller thoracic canal diameters have previously been associated with postoperative neurologic deficits.

OBJECTIVE

This imaging study examined whether postoperative SCS neurologic complaints other than neurologic deficit may be correlated with thoracic spinal canal diameter.

METHODS

Patients who underwent thoracic laminotomy for SCS paddle lead placement between January 2018 and March 2023 were identified. Preoperative thoracic canal diameter was measured on MRI or CT imaging in the sagittal plane from T5/6 to T11/12. The canal diameters of patients with and without new postoperative neurologic complaints were compared.

RESULTS

Two hundred forty-six patients underwent thoracic laminotomy for SCS paddle lead placement. Thoracic radiculopathy, abdominal pain, and lower extremity paresthesia occurred in 3.7% (9/246), 2.8% (7/246), and 2.0% (5/246) patients, respectively. The mean canal diameter for patients without neurologic complaint, thoracic radiculopathy, abdominal pain, and lower extremity paresthesia was 13.1 mm, 12.0 mm (p < 0.0001), 12.1 mm (p < 0.01), and 12.8 mm (p = 0.365), respectively.

CONCLUSION

A smaller thoracic canal diameter is associated with postoperative thoracic radiculopathy and abdominal pain. We believe that surgical planning to create adequate space for SCS leads is critical in preventing postoperative neurologic complaints of deficit, thoracic radiculopathy, and abdominal pain.

The Effect of Various Spinal Neurostimulation Paradigms on the Supraspinal Somatosensory Evoked Response: A Systematic Review

INTRODUCTION

Spinal neurostimulation is a therapy for otherwise intractable chronic pain. Spinal neurostimulation includes stimulation of the spinal cord (SCS), dorsal root ganglion (DRGS), and dorsal root entry zone (DREZS). New paresthesia-free neurostimulation paradigms may rely on different mechanisms of action from those of conventional tonic neurostimulation. The aim of this systematic review is to assess the existing knowledge on the effect of spinal neurostimulation on somatosensory processing in patients with chronic pain. We therefore reviewed the existing literature on the effect of various spinal neurostimulation paradigms on the supraspinal somatosensory evoked response (SER).

MATERIALS AND METHODS

Multiple scientific data bases were searched for studies that assessed the effect of spinal neurostimulation on the supraspinal SER, evoked by painful or nonpainful peripheral stimuli in patients with chronic pain. We found 205 studies, of which 24 were included. Demographic data, study design, and study outcome were extracted.

RESULTS

Of the 24 included studies, 23 used electroencephalography to assess the SER; one study used magnetoencephalography. Fifteen studies evaluated tonic SCS; six studies (also) evaluated paresthesia-free paradigms; three studies evaluated the effect of tonic DRGS or DREZS. Sixteen studies used nonpainful stimuli to elicit the SER, 14 observed a decreased SER amplitude. Ten studies used painful stimuli to elicit the SER, yielding mixed results.

DISCUSSION

The included studies suggest that both paresthesia-based and paresthesia-free spinal neurostimulation paradigms can decrease (part of) the SER elicited by a nonpainful peripheral stimulus. The observed SER amplitude reduction likely is the effect of various spinal and supraspinal mechanisms of spinal neurostimulation that also contribute to pain relief.

CONCLUSIONS

Spinal neurostimulation modulates the processing of a peripherally applied nonpainful stimulus. For painful stimuli, the results are not conclusive. It is not yet clear whether paresthesia-free neurostimulation affects the SER differently from paresthesia-based neurostimulation.

Emotional and psychosocial function after dorsal column spinal cord stimulator implantation: a systematic review and meta-analysis

BACKGROUND

The efficacy of spinal cord stimulation (SCS) in chronic pain studies is traditionally assessed by pain scores, which do not reflect the multidimensional nature of pain perception. Despite the evidence of SCS's influence on emotional functioning comprehensive assessments of its effect remain lacking.

OBJECTIVE

To assess changes in emotional and psychosocial functioning in patients who underwent SCS implantation for chronic pain.

EVIDENCE REVIEW

Ovid MEDLINE, EMBASE, PsychINFO, Cochrane CENTRAL and Scopus databases were searched for original peer-reviewed publications reporting emotional functioning after SCS. The primary outcomes were a pooled mean difference (MD) in anxiety, depression, global functioning, mental well-being and pain catastrophizing at 12 months. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) was used to determine the quality of evidence.

FINDINGS

Thirty-two studies were included in the primary analysis. Statistically significant improvements were observed in anxiety (MD -2.16; 95% CI -2.84 to -1.49; p<0.001), depression (MD -4.66; 95% CI -6.26 to -3.06; p<0.001), global functioning (MD 20.30; 95% CI 14.69 to 25.90; p<0.001), mental well-being (MD 4.95; 95% CI 3.60 to 6.31; p<0.001), and pain catastrophizing (MD -12.09; 95% CI -14.94 to -9.23; p<0.001). Subgroup analyses revealed differences in Global Assessment of Functioning and mental well-being based on study design and in depression based on waveform paradigm.

CONCLUSION

The results highlight the statistically and clinically significant improvements in emotional and psychosocial outcomes in patients with chronic pain undergoing SCS therapy. However, these results need to be interpreted with caution due to the very low certainty of evidence per the GRADE criteria.

PROSPERO REGISTRATION

CRD42023446326.

Analysis of spinal canal diameter in the placement of thoracic spinal cord stimulator paddle leads

BACKGROUND

Neurologic deficit is known as a rare complication of thoracic spinal cord stimulator (SCS) paddle lead implantation, but many believe its incidence after SCS paddle lead placement is under-reported. It is possible that imaging characteristics may be used to help predict safe paddle lead placement.

OBJECTIVE

This imaging study was undertaken to determine the minimum canal diameter required for safe paddle lead placement.

METHODS

Patients who underwent thoracic laminotomy for new SCS paddle lead placement from January 2018 to March 2023 were identified retrospectively. Preoperative thoracic canal diameter was measured in the sagittal plane perpendicular to the disc space from T5/6 to T11/12. These thoracic levels were chosen because they span the most common levels targeted for SCS placement. Patients with and without new neurologic deficits were compared using a Mann-Whitney U-test.

RESULTS

Of 185 patients initially identified, 180 had thoracic imaging available for review. One (0.5%) and 2 (1.1%) of 185 patients complained of permanent and transient neurologic deficit after thoracic SCS placement, respectively. Patients with neurologic deficits had average canal diameters of <11 mm. The average canal diameter of patients with and without neurologic deficits was 10.2 mm (range 6.1-12.9 mm) and 13.0 mm (range 5.9-20.2), respectively (p < 0.0001).

CONCLUSION

Postoperative neurologic deficit is an uncommon complication after thoracic laminotomy for SCS paddle lead placement. The authors recommend ensuring a starting thoracic canal diameter of at least 12 mm to accommodate a SCS paddle lead measuring 2 mm thick to ensure a final diameter of >10 mm. If canal diameter is <12 mm, aggressive undercutting of the lamina, a second laminotomy, or placement of smaller SCS wire leads should be considered.

A Bibliometric Analysis of Top-Cited Journal Articles Related to Neuromodulation for Chronic Pain

OBJECTIVES

Since its foundation in the 1960s, neuromodulation has become an increasingly used treatment option for chronic pain. This bibliometric analysis examines the most cited research in this field with the aim of uncovering existing trends and future directions.

MATERIALS AND METHODS

Clarivate's Web of Science data base was searched for the top 25 most cited studies focusing on neuromodulation for chronic pain. Various bibliometric parameters were then extracted and analyzed. Randomized controlled trials (RCTs) were compared with non-RCTs.

RESULTS

The top 25 articles had a mean of 347 citations and 22.2 citations per year, with more recent articles having a higher citation rate. Most were published in the last two decades and predominantly originated from the United States. There were 13 RCTs, which were significantly more recent (p = 0.004) and more cited per year (p = 0.001) than the 12 non-RCTs. Sources included 15 journals with a mean impact factor of 13.896. The most studied modality was spinal cord stimulation with 20 articles (76.9%), followed by intrathecal drug delivery (15.4%), dorsal root ganglion stimulation (3.8%), and peripheral nerve stimulation (3.8%).

CONCLUSIONS

Analysis of the most cited articles on neuromodulation reveals a focal shift from historical reports to innovative RCTs that have increasingly guided pain practice in the recent years. As novel techniques and technologies continue to develop, high-quality evidence coupled with broadening indications will likely direct further expansion of this field.

Intraoperative Neurophysiological Monitoring During Spinal Cord Stimulation Surgery: A Systematic Review

OBJECTIVES

This study aims to describe the state of literature regarding the use of intraoperative neurophysiological monitoring (IONM) during spinal cord stimulator surgery.

MATERIALS AND METHODS

A systematic review of the use of IONM during spinal cord stimulation (SCS) surgery was performed using the following three data bases: PubMed, Ovid MEDLINE, and Embase. Research techniques included systematic research following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol by Cochrane, and backward searching. Qualitative analysis of included articles was performed using the methodologic index for nonrandomized studies assessment tool. Direction of effect, consistency across studies, and cost-effectiveness were narratively synthesized.

RESULTS

A total of 15 records were identified through data base searching. All records used IONM methods under general anesthesia for guidance of epidural lead placement. IONM techniques used for determining lateralization in the found articles were compound muscle action potentials (CMAPs) (n = 8), somatosensory evoked potentials (SSEPs) (n = 3) or both (n = 4). Motor evoked potentials were used in three trials for neuroprotection purposes. Two studies were comparative, and 12 were noncomparative.

CONCLUSIONS

We found a good body of level II evidence that using IONM during SCS surgery is a valid alternative to awake surgery and may even be superior regarding pain management, cost-effectiveness, and postoperative neurologic deficits. In direct comparison, the found evidence suggested using CMAP provided more consistently favorable results than using SSEP for midline placement of epidural leads under general anesthesia. Selection of IONM modality should be made on the basis of pathophysiology of disease, individual IONM experience, and the individual patient.

Long-term efficacy of high-frequency (10 kHz) spinal cord stimulation for the treatment of painful diabetic neuropathy: 24-Month results of a randomized controlled trial

AIMS

To evaluate the long-term efficacy of high-frequency (10 kHz) spinal cord stimulation (SCS) for treating refractory painful diabetic neuropathy (PDN).

METHODS

The SENZA-PDN study was a prospective, multicenter, randomized controlled trial that compared conventional medical management (CMM) alone with 10 kHz SCS plus CMM (10 kHz SCS+CMM) in 216 patients with refractory PDN. After 6 months, participants with insufficient pain relief could cross over to the other treatment. In total, 142 patients with a 10 kHz SCS system were followed for 24 months, including 84 initial 10 kHz SCS+CMM recipients and 58 crossovers from CMM alone. Assessments included pain intensity, health-related quality of life (HRQoL), sleep, and neurological function. Investigators assessed neurological function via sensory, reflex, and motor tests. They identified a clinically meaningful improvement relative to the baseline assessment if there was a significant persistent improvement in neurological function that impacted the participant's well-being and was attributable to a neurological finding.

RESULTS

At 24 months, 10 kHz SCS reduced pain by a mean of 79.9% compared to baseline, with 90.1% of participants experiencing ≥50% pain relief. Participants had significantly improved HRQoL and sleep, and 65.7% demonstrated clinically meaningful neurological improvement. Five (3.2%) SCS systems were explanted due to infection.

CONCLUSIONS

Over 24 months, 10 kHz SCS provided durable pain relief and significant improvements in HRQoL and sleep. Furthermore, the majority of participants demonstrated neurological improvement. These long-term data support 10 kHz SCS as a safe and highly effective therapy for PDN.

TRIAL REGISTRATION

ClincalTrials.gov Identifier, NCT03228420.

Spinal Cord Stimulation for Failed Back Surgery Syndrome: to Trial or Not to Trial?

Spinal cord stimulation (SCS) is a recommended therapy to treat failed back surgery syndrome (FBSS). A trial period is practiced to enhance patient selection. However, its fundamental evidence is limited, especially concerning long-term benefit and therapy safety. We compared the long-term (5.3 ± 4.0 years) clinical outcome and therapy safety of a trialed and nontrialed implantation strategy, including multidimensional variables and pain intensity fluctuations over time. A multicenter cohort analysis was performed in 2 comparable groups of FBSS patients. Regarding eligibility, patients had to be treated with SCS for at least 3 months. While the Trial group comprised patients who underwent an SCS implantation after a successful trial, the No-Trial group encompassed patients who underwent complete implantation within 1 session. The primary outcome measures were pain intensity scores and complications. The Trial and No-Trial groups consisted of 194 and 376 patients (N = 570), respectively. A statistically but not clinically significant difference in pain intensity (P = .003; effect = 0.506 (.172-.839)) was found in favor of the Trial group. No interaction between a time dependency effect and pain intensity was noted. Whereas trialed SCS patients were more likely to cease opioid usage (P = .003; OR = .509 (.326-.792)), patients in the No-Trial group endured fewer infections (P = .006; proportion difference = .43 (.007-.083)). Although the clinical relevance of our findings should be proven in future studies, this long-term real-world data study indicates that patient-centered assessments on whether an SCS trial should be performed have to be investigated. According to the current ambiguous evidence, SCS trials should be considered on a case-by-case basis. PERSPECTIVE: The currently available comparative evidence, together with our results, remains ambiguous on which SCS implantation strategy might be deemed superior. An SCS trial should be considered on a case-by-case basis, for which further investigation of its clinical utility in certain patient populations or character traits is warranted.

Painful Peripheral Neuropathies of the Lower Limbs and/or Lower Extremities Treated with Spinal Cord Stimulation: A Systematic Review with Narrative Synthesis

Introduction

Painful peripheral neuropathy (PPN) is a debilitating condition with varied etiologies. Spinal cord stimulation (SCS) is increasingly used when conservative treatments fail to provide adequate pain relief. Few published reviews have examined SCS outcomes in all forms of PPN.

Methods

We conducted a systematic review of SCS in PPN. The PubMed database was searched up to February 7th, 2022, for peer-reviewed studies of SCS that enrolled PPN patients with pain symptoms in their lower limbs and/or lower extremities. We assessed the quality of randomized controlled trial (RCT) evidence using the Cochrane risk of bias tool. Data were tabulated and presented narratively.

Results

Twenty eligible studies documented SCS treatment in PPN patients, including 10 kHz SCS, traditional low-frequency SCS (t-SCS), dorsal root ganglion stimulation (DRGS), and burst SCS. In total, 451 patients received a permanent implant (10 kHz SCS, n=267; t-SCS, n=147; DRGS, n=25; burst SCS, n=12). Approximately 88% of implanted patients had painful diabetic neuropathy (PDN). Overall, we found clinically meaningful pain relief (≥30%) with all SCS modalities. Among the studies, RCTs supported the use of 10 kHz SCS and t-SCS to treat PDN, with 10 kHz SCS providing a higher reduction in pain (76%) than t-SCS (38-55%). Pain relief with 10 kHz SCS and DRGS in other PPN etiologies ranged from 42-81%. In addition, 66-71% of PDN patients and 38% of nondiabetic PPN patients experienced neurological improvement with 10 kHz SCS.

Conclusion

Our review found clinically meaningful pain relief in PPN patients after SCS treatment. RCT evidence supported the use of 10 kHz SCS and t-SCS in the diabetic neuropathy subpopulation, with more robust pain relief evident with 10 kHz SCS. Outcomes in other PPN etiologies were also promising for 10 kHz SCS. In addition, a majority of PDN patients experienced neurological improvement with 10 kHz SCS, as did a notable subset of nondiabetic PPN patients.

Early Experience With a Novel Miniaturized Spinal Cord Stimulation System for the Management of Chronic Intractable Pain of the Back and Legs

INTRODUCTION

A novel, spinal cord stimulation (SCS) system with a battery-free miniaturized implantable pulse generator (IPG) was used in this feasibility study. The system uses an external power source that communicates bidirectionally with the IPG (< 1.5 cm³). Human factors, subject comfort, and effects on low back and leg pain were evaluated in this first-in-human study.

MATERIALS AND METHODS

A prospective, multicenter, open-label clinical trial was initiated to evaluate the safety and performance of a novel miniaturized stimulator in the treatment of chronic, intractable leg and low-back pain. Eligible subjects were recruited for the study and gave consent. Subjects who passed the screening/trial phase (defined as ≥ 50% decrease in pain) continued to the long-term implant phase and were followed up at predefined time points after device activation. Interim clinical and usability outcomes were captured and reported at 90 days.

RESULTS

Results of 22 subjects who chose a novel pulsed stimulation pattern therapy using the battery-free IPG (< 1.5 cm³) are described here. At 90-days follow-up, the average pain reduction was 79% in the leg (n = 22; p < 0.0001) and 76% in the low back (n = 21; p < 0.0001) compared with baseline. Responder rates (≥ 50% pain relief) at 90 days were 86% in leg pain (19/22) and 81% in low-back pain (17/21). Subjects rated the level of comfort of the external wearable power source to be 0.41 ± 0.73 at 90 days on an 11-point rating scale (0 = very comfortable, 10 = very uncomfortable).

DISCUSSION

These interim results from the ongoing study indicate the favorable efficacy and usability of a novel, externally powered, battery-free SCS IPG (< 1.5 cm³) for leg and low-back pain. Study subjects wore the external power source continuously and found it comfortable, and the system provided significant pain relief. These preliminary findings warrant further investigation.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is ACTRN12618001862235.

Indirect Comparison of 10 kHz Spinal Cord Stimulation (SCS) versus Traditional Low-Frequency SCS for the Treatment of Painful Diabetic Neuropathy: A Systematic Review of Randomized Controlled Trials

Spinal cord stimulation (SCS) is increasingly used to treat painful diabetic neuropathy (PDN). At the time of a recent meta-analysis in this field, data were only available from randomized controlled trials (RCTs) of traditional low-frequency SCS (LF-SCS). However, outcomes from high-frequency 10 kHz SCS treatment are now available. Our study aimed to systematically review the contemporary evidence for SCS in patients with lower limb pain due to PDN and include an indirect comparison of the high- and low-frequency modalities. We searched the PubMed/CENTRAL databases up to 18 August 2022, for peer-reviewed RCTs of SCS that enrolled PDN patients with lower limb pain symptoms. The quality of the evidence was assessed with the Cochrane Risk of Bias tool. Using SCS treatment arm data from the RCTs, we indirectly compared the absolute treatment effect of 10 kHz SCS and LF-SCS. Results are presented in tables and forest plots. This systematic review was reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines. Three RCTs met our eligibility criteria, including the recent 10 kHz SCS RCT (N = 216, 90 implanted) and 2 others that examined LF-SCS (N = 36, 17 implanted; N = 60, 37 implanted). Our analysis of 6-month data found clinically meaningful pain relief with each SCS modality. However, significantly greater pain reduction was identified for 10 kHz SCS over LF-SCS: average pain reduction in the 10 kHz SCS cohort was 73.7% compared with 47.5% in the pooled LF-SCS group (p < 0.0001). In the permanent implant subset, the 50% pain reduction responder rate was 83.3% in the 10 kHz SCS cohort versus 63.0% in the pooled LF-SCS group (p = 0.0072). The overall risk of bias of each included RCT was deemed high, mainly due to the absence of patient blinding. Our analysis indicates that paresthesia-free 10 kHz SCS can provide superior pain relief and responder rate over LF-SCS for managing PDN patients refractory to conventional medical management.

Neuropeptides in Cancer: Friend and Foe?

Neuropeptides are small regulatory molecules found throughout the body, most notably in the nervous, cardiovascular, and gastrointestinal systems. They serve as neurotransmitters or hormones in the regulation of diverse physiological processes. Cancer cells escape normal growth control mechanisms by altering their expression of growth factors, receptors, or intracellular signals, and neuropeptides have recently been recognized as mitogens in cancer growth and development. Many neuropeptides and their receptors exist in multiple subtypes, coupling with different downstream signaling pathways and playing distinct roles in cancer progression. The consideration of neuropeptide/receptor systems as anticancer targets is already leading to new biological and diagnostic knowledge that has the potential to enhance the understanding and treatment of cancer. In this review, recent discoveries regarding neuropeptides in a wide range of cancers, emphasizing their mechanisms of action, signaling cascades, regulation, and therapeutic potential, are discussed. Current technologies used to manipulate and analyze neuropeptides/receptors are described. Applications of neuropeptide analogs and their receptor inhibitors in translational studies and radio-oncology are rapidly increasing, and the possibility for their integration into therapeutic trials and clinical treatment appears promising.

Ethical Considerations in the Implantation of Neuromodulatory Devices

OBJECTIVES

Neuromodulatory devices are increasingly used by neurosurgeons to manage a variety of chronic conditions. Given their potential benefits, it is imperative to create clear ethical guidelines for the use of these devices. We present a tiered ethical framework for neurosurgeon recommendations for the use of neuromodulatory devices.

MATERIALS AND METHODS

We conducted a literature review to identify factors neurosurgeons should consider when choosing to offer a neuromodulatory device to a patient.

RESULTS

Neurosurgeons must weigh reductions in debilitating symptoms, improved functionality, and preserved quality of life against risks for intraoperative complications and adverse events due to stimulation or the device itself. Neurosurgeons must also evaluate whether patients and families will maintain responsibility for the management of neuromodulatory devices. Consideration of these factors should occur on an axis of resource allocation, ranging from provision of neuromodulatory devices to those with greatest potential benefit in resource-limited settings to provision of neuromodulatory devices to all patients with indications in contexts without resource limitations. Neurosurgeons must also take action to promote device effectiveness throughout the duration of care.

CONCLUSIONS

Weighing risks and benefits of providing neuromodulatory devices and assessing ability to remain responsible for the devices on the level of the individual patient indicate which patients are most likely to achieve benefit from these devices. Consideration of these factors on an axis of resource allocation will allow for optimal provision of neuromodulatory devices to patients in settings of varied resources. Neurosurgeons play a primary role in promoting the effectiveness of these devices.

Dorsal root entry zone procedure and other surgeries for pain

Pain is a very common symptom that often serves a protective function. It is typically treated medically. When pain becomes chronic and intractable, it no longer serves a protective function and often requires more aggressive forms of treatment. Many types of surgeries can be performed for the management of pain. These surgeries can involve ablation (destruction) or augmentation (stimulation or facilitation) of some part of the nervous system. In many of these surgeries, neurophysiologic intraoperative monitoring (NIOM) is not needed, however, in others neuromonitoring serves a mapping and monitoring purpose. The prototype of pain surgery for this chapter is the dorsal root entry zone (DREZ) procedure. Both mapping and monitoring can help improve lesioning precision and outcomes in this surgery. In this chapter, the DREZ procedures and other surgeries for primarily pain relief in which NIOM is used are discussed. Surgeries, such as spinal stenosis, in which pain relief is important but not the sole purpose, are not discussed here and are covered elsewhere.

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.

Complete resolution of chronic pain, sensory impairment, and motor dysfunction following percutaneous transforaminal endoscopic decompression in a failed back surgery syndrome patient-a case report

Failed back surgery syndrome (FBSS) is an increasingly common problem that presents a clinical challenge. Though usual treatments may improve pain for some period of time, they do not provide clinically significant recovery of subjective numbness and weakness. We describe a case of a 48-year-old female with FBSS, who presented to the pain clinic with a 29-year history of low back pain, and a 7-year history of sensory and motor dysfunction of her left lower extremity, ever since a left hemi-laminectomy. At the time of presentation, she was wheelchair bound with intense pain, 4/5 strength in her left lower extremity proximally, and 3/5 strength distally. She had previously failed conservative management including medications, physical therapy, and epidural and facet injections. During percutaneous transforaminal endoscopic decompression, her transiting left L5 nerve root was found to be encased in thick scar tissue. The entirety of this scar tissue entrapping her L5 nerve was able to be released, resulting in not only complete resolution of pain but full return of sensory and motor function; in fact, the patient was able to walk out of the post anesthesia care unit without any assistive devices. Despite long-standing damage from many years of nerve entrapment, this patient's sensory and motor function was able to be restored simply by freeing her nerve of scar tissue. Thus, if nerve entrapment in scar tissue is the cause of FBSS, transforaminal endoscopic decompression may offer not only pain relief, but also return of sensory and motor function.

Experiences From the Patient Perspective on Spinal Cord Stimulation for Failed Back Surgery Syndrome: A Qualitatively Driven Mixed Method Analysis

INTRODUCTION

When neither pharmacological therapies nor alternative interventions provide sufficient pain relief, spinal cord stimulation (SCS) can be used to treat Failed Back Surgery Syndrome (FBSS). Although it seems reasonable that quality of life (QoL)- and psychosocial-related factors contribute to the outcome of SCS since pain is a multidimensional experience, few qualitative studies have explored the expectations of SCS and experiences on SCS to treat FBSS from the patient perspective.

OBJECTIVES

The aim of this study was to qualitatively and quantitatively map the FBSS patients' experiences with SCS and the effects of SCS on low back pain caused by FBSS.

MATERIALS AND METHODS

A qualitative study with in-depth semi-structured interviews, assisted by the Brief Pain Inventory (BPI)-questionnaire.

RESULTS

Seven themes regarding patients' experiences, subdivided into 15 categories, were identified, including an understudied theme within this field of research, Spiritual Well-Being. "Acceptance" and "coping" emerged as pre-eminent motifs throughout these themes. Moreover, the realization of patients' expectations were variable throughout the presented themes. According to the BPI Questionnaire, four out of 13 patients (31%) had significant pain relief (≥50%). Seven out of 13 (54%) reported a ≥50% increase regarding enjoyment of life.

CONCLUSION

Multiple QoL- and psychosocial-related themes are related to SCS-outcomes. In order to improve SCS-outcomes for both short- and long-term, these themes should be implemented as a multidimensional approach, both prior to implantation as during follow-up.

Risk Factors and Survival Analysis of Spinal Cord Stimulator Explantation

OBJECTIVE

The treatment failure rate for spinal cord stimulators (SCS) remains unacceptably high, with reports of removal in up to 30% of patients. The purpose of this study is to perform survival and multivariate regression analyses of patients who have undergone SCS explantation in order to identify patient characteristics that may predict treatment failure.

MATERIALS AND METHODS

We identified 253 patients who underwent SCS placement using current procedural terminology codes in a private health insurance data base spanning 2003-2016. Patient demographics, opioid use, surgical indications, as well as comorbidities were noted. At least 6 months of continuous claims data before and after implantation were required for inclusion. Patients who underwent explantation were defined as those who underwent removal without replacement within 90 days and had at least 90 days of continuous insurance eligibility following removal. Those who underwent removal for infectious reasons were identified with corresponding diagnosis codes.

RESULTS

Of the 252 patients who met the inclusion criteria, 17 (6.7%) underwent SCS explantation. Median follow-up time was 2.0 years. Of those who had their system explanted, six patients (2.8%) had their systems removed for infection and 11 (4.3%) for noninfectious reasons. Bivariate analysis revealed that younger age and tobacco use were associated with an increased likelihood of explantation. The Cox proportional hazards analysis demonstrated that younger age, tobacco use, and the presence of "other" mental health disorders were predictive of explantation.

CONCLUSIONS

In a cohort of SCS patients from multiple institutions, this study demonstrates that explantation for noninfectious reasons is more likely in younger patients, tobacco users, and those with certain psychiatric conditions. With an estimated 10% of patients opting to have their devices removed within 5 years of implantation, refining the ability of clinicians to predict who will see benefit from SCS treatment remains necessary.

Enhanced transcutaneous electrical nerve stimulation achieved by a localized virtual bipole: a computational study of human tibial nerve stimulation

OBJECTIVE

Electrical neuromodulation is a clinically effective therapeutic instrument, currently expanding into newer indications and larger patient populations. Neuromodulation technologies are also moving towards less invasive approaches to nerve stimulation. In this study, we investigated an enhanced transcutaneous electrical nerve stimulation (eTENS) system that electrically couples a conductive nerve cuff with a conventional TENS electrode. The objectives were to better understand how eTENS achieves lower nerve activation thresholds, and to test the feasibility of applying eTENS in a human model of peripheral nerve stimulation.

APPROACH

A finite element model (FEM) of the human lower leg was constructed to simulate electrical stimulation of the tibial nerve, comparing TENS and eTENS. Key variables included surface electrode diameter, nerve cuff properties (conductivity, length, thickness), and cuff location. Enhanced neural excitability was predicted by relative excitability (RE > 1), derived using either the activating function (AF) or the nerve activation threshold (MRG model).

MAIN RESULTS

Simulations revealed that a localized 'virtual bipole' was created on the target nerve, where the isopotential surface of the cuff resulted in large potential differences with the surrounding tissue. The cathodic part (nerve depolarization) of the bipole enhanced neural excitability, predicted by RE values of up to 2.2 (MRG) and 5.5 (AF) when compared to TENS. The MRG model confirmed that action potentials were initiated at the cathodic edge of the nerve cuff. Factors contributing to eTENS were larger surface electrodes, longer cuffs, cuff conductivity (>1×10³ S m^-1), and cuff position relative to the cathodic surface electrode.

SIGNIFICANCE

This study provides a theoretical basis for designing and testing eTENS applied to various neural targets and data suggesting function of eTENS in large models of nerve stimulation. Although eTENS carries key advantages over existing technologies, further work is needed to translate this approach into effective clinical applications.

Spinal cord stimulation programming: a crash course

The aim of this comprehensive review is to provide an instructional guide for providers regarding the parameters and programming of spinal cord stimulation (SCS) devices. Knowing these fundamentals will aid in providing superior pain relief to patients. SCS has four programmable parameters: contact (electrode) selection, amplitude, pulse width, and frequency. Each parameter needs to be accounted for when assessing which program works for which patient. Traditional open-loop systems allow for different "programs," or combinations of these four parameters, to be pre-set by the provider and medical device representative. These allow for flexibility in the type of stimulation delivered to the patient depending on activity. Patients are also given control over programs and changing the amplitudes of these programs. However, some open-loop systems place the burden of toggling between programs to manage pain control on patients, though this tends to be less in subparesthesia programs. Newer closed-loop systems make it possible for stimulation settings to automatically adjust in response to accelerometry and evoked compound action potential feedback, and therefore have the potential to streamline the patient experience. This article provides practitioners with the basic knowledge of SCS parameters and programming systems. Understanding their use is essential to providing optimal pain relief to patients.

Development of an Educational Curriculum for Spinal Cord Stimulation

BACKGROUND

Spinal cord stimulators (SCSs) are used for treating chronic pain. The number of SCSs implanted each year is on the increase. The North American Neuromodulation Society (NANS) education committee aimed to develop a SCS curriculum as a tool to guide physicians at different training levels, based on the most recent evidence.

MATERIAL AND METHODS

A multidisciplinary (anesthesiology, physical medicine, neurosurgery, and neurology), taskforce representing the education committee of the NANS met to develop a SCS curriculum following the Accreditation Council for Graduate Medical Education (ACGME) milestones. The task force used the best available evidence and knowledge to develop the curriculum. Once developed, the SCS curriculum was then approved by the NANS board.

RESULTS

The task force developed a SCS training curriculum. Milestones included patient care and procedural skills, system-based practice, medical knowledge, interpersonal communication, practice based learning and professionalism. Each milestone was defined for three categories, early learner, advanced learner, and practitioner.

CONCLUSION

A multidisciplinary task force of the NANS education committee developed a SCS training curriculum that defines ACGME milestones for basic learners, advanced learners, and practitioners.

Sensor driven-position adaptive versus conventional spinal cord stimulation in failed back surgery syndrome: a retrospective case series

Background

Failed back surgery syndrome (FBSS) is a common problem affecting 20–40% of cases undergoing spine surgeries. Spinal cord stimulation (SCS) has been shown to be an efficient and relatively safe treatment in managing many intractable chronic pain syndromes.

Objectives

This study compares the efficacy and safety of MR-compatible sensor driven-position adaptive SCS and conventional SCS in treating FBSS.

Methods

This is a retrospective case series of 120 consecutive FBSS patients who underwent SCS between February 2011 and March 2018. Pain levels, analgesic/opioid use, and sleep problems were assessed before and 3 months after the procedure in patients who received either conventional SCS (group 1; n = 62) or sensor-driven position adaptive SCS (group 2; n = 34). The degree of patient satisfaction, the change in the activities of daily living (ADLs) together with the rate of complications were compared in both treatment groups.

Results

The two treatment groups were homogenous at baseline. Patients in both groups improved significantly regarding pain, opioid consumption, sleep, and ADLs. The magnitude of improvement was statistically higher in group 2. An absolute reduction of 6 points on the VAS in patients who received position adaptive SCS vs a 3.3 point reduction in conventional SCS cases (p < 0.0001). Half of the patients in group 2 (n = 17) showed excellent satisfaction after the procedure versus 14.5% of cases in group 1 (n = 9).

Conclusion

SCS is an efficient and reliable treatment in FBSS. MR-compatible sensor driven-position adaptive SCS can be a more effective treatment in this patient group.

Waves of Pain Relief: A Systematic Review of Clinical Trials in Spinal Cord Stimulation Waveforms for the Treatment of Chronic Neuropathic Low Back and Leg Pain

In the United States, chronic low back pain affects up to 37% of adults and is a multibillion dollar health care expenditure. Spinal cord simulation (SCS) has been established as an effective treatment alternative for chronic neuropathic low back and leg pain, especially for patients with failed back surgery syndrome or chronic regional pain syndrome. The field of SCS has rapidly advanced such that analgesia can now be achieved through numerous different waveforms, each claiming to offer improved outcomes. These waveforms include traditional paresthesia-based SCS (<100 Hz), paresthesia-free high-frequency SCS (5-10 kHz), burst SCS, and subperception SCS (1-5 kHz). Level 1 evidence critically evaluating the efficacy of these different waveforms is lacking. We conducted a systematic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify all randomized controlled trials of SCS in the treatment of chronic neuropathic low back and leg pain, failed back surgery syndrome, or chronic regional pain syndrome. Of 38 eligible studies reviewed, 13 randomized controlled trials were finally included in our systematic review. We reviewed evidence from randomized controlled trials in the field of SCS that have established paresthesia-based SCS, paresthesia-free high-frequency SCS, burst SCS, and subperception SCS as viable treatment options for chronic neuropathic low back and leg pain. We critically evaluated evidence that claims to support the use of one waveform over another and reviewed the literature on patient preference for different waveforms.

Does Spinal Cord Stimulation Due to Failed Back Surgery Syndrome Lead to Permanent Occupational Disability?

OBJECTIVE

Spinal cord stimulation (SCS) is a recommended treatment method for patients afflicted by failed back surgery syndrome (FBSS). Although SCS is shown to be clinically effective, not many patients return to work (RTW). The aim of this study is to assess the RTW rate of these patients.

MATERIALS AND METHODS

We prospectively evaluated 102 patients with FBSS, managed by low frequency SCS at a single institution in Poland. RTW rate was the main endpoint in the study. Additionally, we browsed the first 300 records in Google and extracted the suggested RTW time post-SCS implantation.

RESULTS

Mean follow-up was 8.5 years. 79.4% of patients were actively working at the baseline. Fifteen patients were sick leave benefit claimants (15/81; 18.5%) and six were permanently disabled (6/81; 7.4%). In the follow-up, 40 did not change their work status. Only 2 of 21 patients resumed work and the total RTW rate was 9.5%. On the other hand, 38 of 81 patients (46.9%), who actively worked before SCS, gained disability status. Out of entire group, 20.6% (21 of 102) were not working at the baseline and 55.9% (57 of 102) were not working in the follow-up. Neither factor influenced RTW rate. In the second stage of the study, internet data search yielded a mean RTW time of 6.1 weeks.

CONCLUSIONS

Unlike the well-analyzed effectiveness of SCS, RTW remains an underutilized outcome measure. The RTW rate in our series was the second lowest in the reviewed literature. We demonstrated that half of the patients with an implanted SCS either did not resume their work or left their job.

The Use of Spinal Cord Stimulation/Neuromodulation in the Management of Chronic Pain

Chronic pain causes a tremendous burden on the society in terms of economic factors and social costs. Rates of spinal surgery, especially spinal fusion, have increased exponentially over the past decade. The opioid epidemic in the United States has been one response to the management of pain, but it has been fraught with numerous catastrophic-related adverse effects. Clinically, spinal cord stimulation (SCS)/neuromodulation has been used in the management of chronic pain (especially spine-related pain) for more than two decades. More recent advances in this field have led to new theories and approaches in which SCS can be used in the management of chronic spine-related pain with precision and efficacy while minimizing adverse effects commonly seen with other forms of chronic pain treatment (eg, narcotics, injections, ablations). Narcotic medications have adverse effects of habituation, nausea, constipation, and the like. Injections sometimes lack efficacy and can have only limited duration of efficacy. Also, they can have adverse effects of cerebrospinal fluid leak, infection, and so on. Ablations can be associated with burning discomfort, lack of efficacy, recurrent symptoms, and infection. High-frequency stimulation, burst stimulation, tonic stimulation with broader paddles, and new stimulation targets such as the dorsal root ganglion hold promise for improved pain management via neuromodulation moving forward. Although a significant rate of complications with SCS technology are well described, this can be a useful tool in the management of chronic spine-related pain.

The impact of obesity on the effectiveness of spinal cord stimulation in chronic spine-related pain patients

BACKGROUND CONTEXT

Chronic pain and obesity are both on the rise. Spinal cord stimulation has gained increasing popularity in the pain management field for the treatment of spine-related chronic pain, however to-date, the correlation between the spinal cord stimulator effectiveness and increasing body mass index (BMI) has not been fully established.

PURPOSE

We aimed to investigate the correlation between patients' BMI and the percentage of pain relief as well as opioid utilization in chronic spine-related pain patients treated with spinal cord stimulation.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Patients with chronic spine-related pain who were treated with a spinal cord stimulator.

OUTCOME MEASURES

Eleven-point numeric rating scale for pain and opioid utilization.

METHODS

Following Institutional Review Board approval, data from all eligible subjects who had undergone successful spinal cord stimulation (SCS)-trial defined as ≥50% decrease in pain followed by SCS implant were collected and statistically analyzed. Patients were divided into four groups according to BMI. Self-reported pain scores on the 11-point numerical rating scale were collected at baseline, 6 months and 12 months post SCS-implant visits. Opioid utilization, if any, was collected at baseline and 12 months post-SCS implant.

RESULTS

In all, 181 patients were included. Thirty-three were under and/or normal weight (≤24.9 kg/m²), 72 overweight (25.0-29.9 kg/m²), 63 obese (30.0-39.9 kg/m²), and 13 morbidly obese (≥40.0 kg/m2). The estimated coefficients from multivariable linear regression analysis were -1.91% (95% CI: -2.82% to -0.991%) and -1.48% (95% CI: -2.30% to -0.660%) reduction in pain improvement per unit increase of BMI for 6 months and 12 months scores, respectively. The estimated coefficient of disability status was -15.3% (95% CI: -22.1% to -8.48%). The estimated coefficient for 12 month opioid equivalence was -0.08% (95% CI: -0.14 to -0.021), per` 1 mg unit increase of morphine opioid equivalency. The data showed a statistically significant negative association between increasing BMI and SCS effectiveness at 6 and 12 months post-SCS therapy with a 2% reduction in efficacy for every unit increase of BMI after adjusting for confounding factors and a 20% better response in underweight and/or normal patients over the morbidly obese individuals which was not related to baseline pain score level. The significant difference in pain scores at 6 months (p = .0003) and 12 months (p = .04) post-SCS implant between obese and nonobese patients was not attributable to differences in baseline pain scores. There was no significant change in opioid utilization between baseline and 12 months post-SCS therapy.

CONCLUSION

A negative association between SCS effectiveness and increasing BMI was found, whereas, no significant difference was noted amongst the various BMI cohorts and the daily opioid consumption.

Spinal Cord Stimulation in Chronic Pain: A Review of the Evidence

This review looks at the evidence for the effectiveness of spinal cord stimulation in various chronic pain states. Spinal cord stimulation can only be effective when appropriate dorsal column fibres in the spinal cord are preserved and able to be stimulated. Spinal cord stimulation has been shown to have little to offer for patients with some diagnoses. Although 50 to 60% of patients with failed back surgery syndrome obtain significant pain relief with this technique, the strength of the evidence available is insufficient to clearly advocate its use in all patients with this condition. Though limited in quantity and quality, better evidence exists for its use in neuropathic pain, complex regional pain syndrome, angina pectoris and critical limb ischaemia. There is a lack of high quality evidence relating to spinal cord stimulation due to difficulties in conducting randomized controlled trials in this area. Serious methodological problems are encountered in blinding, recruitment and assessment in nearly all published trials of spinal cord stimulation. Suggestions regarding appropriate methodologies for trials which would produce better quality evidence are summarized.

Spinal Cord Stimulation for Neuropathic Pain: Current Trends and Future Applications

The origin and the neural pathways involved in chronic neuropathic pain are still not extensively understood. For this reason, despite the wide variety of pain medications available on the market, neuropathic pain is challenging to treat. The present therapeutic alternative considered as the gold standard for many kinds of chronic neuropathic pain is epidural spinal cord stimulation (SCS). Despite its proved efficacy, the favourable cost-effectiveness when compared to the long-term use of poorly effective drugs and the expanding array of indications and technical improvements, SCS is still worldwide largely neglected by general practitioners, neurologists, neurosurgeons and pain therapists, often bringing to a large delay in considering as a therapeutic option for patients affected by neuropathic chronic pain. The present state of the art of SCS in the treatment of chronic neuropathic pain is here overviewed and speculations on whether to use a trial period or direct implant, to choose between percutaneous leads or paddle electrodes and on the pros and cons of the different patterns of stimulation presently available on the market (tonic stim, high-frequency stim and burst stim) are described.

The Long-Term Durability of Multilumen Concentric Percutaneous Spinal Cord Stimulator Leads

BACKGROUND

Lead fracture is a well-known complication of cylindrical spinal cord stimulator leads. In order to reduce this complication, anchor design and techniques have been modified, but internal lead design has received little attention.

OBJECTIVES

The goal of this study was to study the impact of lead design by a retrospective determination of the fracture rate of multilumen concentric (MLC) 8-contact leads.

STUDY DESIGN

Retrospective chart review.

SETTING

University teaching hospital.

METHODS

A registry of spinal cord stimulator implants and corresponding billing data were used to identify patients. Procedural details were reviewed for technique, lead insertion, anchoring details, manufacturer, and lead longevity from 2002 to 2014. Data storage was in RedCap data-capturing software (REDCap eData Collection web-based application). All analyses were performed using SAS 9.3 (SAS Institute, Cary, NC, U.S.A.).

RESULTS

In a near 12"-year time period, 172 patients received 305 permanently implanted 8-contact leads, with an overall fracture rate of 4.3%. Of these, 191 leads were of the MLC design. No lead fracture was observed in the MLC leads over an average 4.5 years of follow-up.

LIMITATION

Retrospective single center.

CONCLUSION

MLC lead design has the potential to significantly mitigate lead fracture.

Use of Spinal Cord Stimulation in Elderly Patients with Multi-Factorial Chronic Lumbar and Non-Radicular Lower Extremity Pain

Spinal cord stimulation (SCS) is an effective treatment for chronic back and limb pain. The criteria for use of SCS for specific problems such as failed back surgery syndrome (FBSS), peripheral neuropathic pain and residual pain after joint replacement is well established. With an aging population, there are more patients presenting with a combination of various multi-factorial chronic pain problems rather than from a single clear cause. It is not uncommon to see patients with chronic back pain years after spine surgery with new additional pain in the area of joint replacement or due to peripheral neuropathy. In most of these patients, one area is the primary cause of their pain, while the other more secondary. Multiple chronic problems complicate the pain management of the primary cause and also can diminish the effect of SCS that only targets the primary problem. The primary and secondary causes of pain were ranked by the patient including the duration of their chronic pain for each area. This helped establish criteria for use of SCS in these complex pain patients. The patients were evaluated initially with an epidural stimulator trial and if they obtained 50% or greater pain relief to the primary pain generating area, permanent implantation of one or more arrays of spinal cord electrodes was performed but planned to cover also the secondary pain areas. Post-implant follow-up evaluation at one, three and six months included measurement of visual analog scale (VAS), use of pain medication and degree of functional activity and behavior. This report looks at the effectiveness of using multiple overlapping electrodes for SCS in patients with multi-factorial chronic pain.

A Temporary vs. Permanent Anchored Percutaneous Lead Trial of Spinal Cord Stimulation: A Comparison of Patient Outcomes and Adverse Events

OBJECTIVES

A trial of spinal cord stimulation (SCS) is a prerequisite to determine efficacy of the therapy prior to placement of a permanent implanted system. A trial may be conducted employing a percutaneously placed temporary cylindrical lead or via a permanently anchored cylindrical lead placed and subsequently secured via open surgical method. There has been little investigation comparing the two methods of trial. This study is a comparative analysis of the two methods both for prediction of success as well as associated morbidity.

STUDY DESIGN

Retrospective chart review.

MATERIALS AND METHODS

SCS outcomes of percutaneous temporary lead trial or the temporary lead (TL) group and permanent anchored lead trial or permanent lead (PL) group were analyzed for lack of relief, poor paresthesia coverage, false positive trial phase, fading relief, and biological complications.

RESULTS

Outcome data was analyzed for 148 patients in the TL group and 138 patients in the PL group. In comparing the two trial methods, false positive rate of trial was higher (p < 0.05) in the PL group as compared to the TL group (6.35 vs. 1.35%). Cumulative wound infections (6.52 vs. 1.35%), and poor wound healing (4.35 vs. 0%) were also significantly higher in the PL group. Rate of success in the trial phase was equal in both groups.

CONCLUSION

The percutaneous temporary lead trial group was associated with fewer false positives and wound related complications as compared to permanent anchored lead trial group. There was very little technical advantage of routinely anchoring the trial lead.

Evaluation of spinal cord stimulation on the symptoms of anxiety and depression and pain intensity in patients with failed back surgery syndrome

BACKGROUND

Spinal cord stimulation (SCS) is now established as the primary treatment for failed back surgery syndrome (FBSS). Commonly, patients with chronic pain and FBSS often report symptoms of anxiety and depression resulting from this condition. These factors can modulate and amplify the pain experience, therefore, further challenging treatment success.

AIMS

This study examined the efficacy of SCS on alleviating the symptoms of anxiety and depression associated with chronic pain as well as pain intensity in a group of patients with FBSS.

METHODS

A convenience sample (n = 26) was selected for participation. Questionnaires [Hospital Anxiety and Depression Scale (HADS) and Brief Pain Inventory Short Form (BPI-SF)] were completed and examined pre and post spinal cord implant.

RESULTS

Analysis of the data 1 year following SCS indicates that there was a statistical significant improvement in the symptoms of depression and anxiety reported as well as pain intensity in all participants (p < 0.001). Both anxiety and depression scores on the HADS were significantly lower compared to baseline (p < 0.001). Pain intensity scores decreased by ≥50% from baseline in all participants. Opioid analgesia was discontinued by 90% (n = 8) of participants.

CONCLUSION

Whilst it is already recognised that SCS reduces pain in FBSS, this study demonstrated that it also reduced the symptoms of anxiety and depression with an associated reduction in opioid consumption.

Spinal Cord Stimulation: An Alternative Concept of Rehabilitation?

BACKGROUND

Chronic low back and leg pain is a disabling condition, affecting, in most cases, older patients with congenital or acquired spinal stenosis or patients with failed back surgery syndrome. Spinal cord stimulation has been introduced as an effective therapeutic option for those patients who have previously been operated without significant clinical benefits, or for all those patients who are ineligible for traditional surgery.

METHODS

We report our experience with ten patients treated with spinal cord stimulation plus medication and physical therapy between November 2014 and September 2015. Inclusion criteria were: previous surgical treatments for lumbar stenosis and metameric instability and persistent or ingravescent disabling low back and leg pain, with a mean duration of symptoms of at least 18 months. A visual analog scale (VAS) was employed for back and leg pain, and the Oswestry Disability Index (ODI) score was determined, and findings were analyzed after 6 months.

FINDINGS

No intra- or postoperative complication was recorded. The mean VAS score for back pain decreased from 7.5 to 2.9, while leg VAS decreased from 8.2 to 3.0. Analysis of ODI values showed evident improvement in daily life activities, ranging from a median value of 75.7% to 32.7 % after the stimulation.

CONCLUSION

Spinal cord stimulation has a recognized impact on the pain and on the quality of life of patients with failed back surgery syndrome.

Spinal Cord Stimulation in Failed Back Surgery Syndrome: Review of Clinical Use, Quality of Life and Cost-Effectiveness

Failed back surgery syndrome (FBSS) is complex and recurrent chronic pain after spinal surgery. Several important patient and surgery related risk factors play roles in development of FBSS. Inadequate selection of the candidates for the spinal surgeries is one of the most crucial causes. The guidelines suggest that conservative management featuring pharmacologic approaches and rehabilitation should be introduced first. For therapy-refractory FBSS, spinal cord stimulation (SCS) is recommended in selected patients. Treatment efficacy for FBSS has increased over the years with the majority of patients experiencing pain relief and reduced medicinal load. Improved quality of life can also be achieved using SCS. Cost-effectiveness of SCS still remains unclear. However evidence for SCS role in FBSS is controversial, SCS can be beneficial for carefully classified patients.

Late Spontaneous Migration of a Dorsal Column Stimulator Paddle Lead

The most frequently encountered complication of dorsal column stimulators is lead migration. The vast majority of these events are seen in the first few weeks to months. Late paddle lead migration is a very uncommon occurrence in this setting. We describe a case of a 51-year-old male with a history of reflex sympathetic dystrophy having undergone dorsal column stimulator insertion at the level of C1-C2. A good clinical benefit was appreciated in the postoperative period once the stimulator was turned on. Approximately six months postoperatively, the patient suddenly lost coverage. Radiographic imaging revealed that the lead had migrated caudally to the C3-C4 level. Subsequent revision surgery took place. This description highlights a common complication, but occurring outside the expected time frame after surgery.

Younger age predicts greater effectiveness of spinal cord stimulation for chronic pain

BACKGROUND

Spinal cord stimulation (SCS) is an accepted surgical treatment for neuropathic pain in failed back syndrome or complex regional pain syndrome. However, even in the best selected surgical cases the predictors of adequate pain control are not well defined. The aim of this study was to identify predictors of outcome in patients who underwent SCS in our center.

METHODS

We performed a retrospective analysis of our neurosurgical database for patients who underwent SCS over the last 8 years in an attempt to identify factors predictive of outcome.

RESULTS

Forty-one patients underwent implantation of epidural electrodes, 34 patients had a successful stimulation trial and received permanent devices. Nine patients experienced a late failure at a median time of 7.8 months (range, 4.5-19 months) after implantation. Age was significantly associated with outcome. Younger patients had a significantly lower rate of treatment failure, and none of the patients above 65 years had a successful long-term outcome.

CONCLUSIONS

Our results suggest that younger age is associated with greater long-term effectiveness of spinal cord stimulation and therefore age may influence the success of SCS therapy with older patients having a greater tendency to failure. Earlier intervention may be beneficial in these chronic pain patients.

Twiddler's syndrome in spinal cord stimulation

Background

The aims are to present a case series of Twiddler’s syndrome in spinal cord stimulators with analysis of the possible mechanism of this syndrome and discuss how this phenomenon can be prevented.

Method

Data were collected retrospectively between 2007 and 2013 for all patients presenting with failure of spinal cord stimulators. The diagnostic criterion for Twiddler’s syndrome is radiological evidence of twisting of wires in the presence of failure of spinal cord stimulation.

Results

Our unit implants on average 110 spinal cord stimulators a year. Over the 5-year study period, all consecutive cases of spinal cord stimulation failure were studied. Three patients with Twiddler’s syndrome were identified. Presentation ranged from 4 to 228 weeks after implantation. Imaging revealed repeated rotations and twisting of the wires of the spinal cord stimulators leading to hardware failure.

Conclusions

To the best of our knowledge this is the first reported series of Twiddler’s syndrome with implantable pulse generators (IPGs) for spinal cord stimulation. Hardware failure is not uncommon in spinal cord stimulation. Awareness and identification of Twiddler’s syndrome may help prevent its occurrence and further revisions. This may be achieved by implanting the IPG in the lumbar region subcutaneously above the belt line. Psychological intervention may have a preventative role for those who are deemed at high risk of Twiddler’s syndrome from initial psychological screening.

Failed back surgery syndrome: a suggested algorithm of care

Failed back surgery syndrome (FBSS) is a complex condition which can be very difficult to treat. In this article, we propose a pragmatic algorithm for the management of the syndrome. The management of this condition should include a comprehensive initial assessment to rule out treatable cause, pharmacological optimisation, psychological techniques and neuromodulation. There is good evidence to support early application of conventional spinal cord stimulation for FBSS patients suffering from predominant buttock and leg pain. Emerging techniques in neuromodulation such as high-frequency spinal cord stimulation, peripheral nerve field stimulation and dorsal root ganglion stimulation hold promise for the future, but long-term outcome regarding efficacy and safety is not yet established. Intrathecal drug delivery systems should also be considered in those who are unsuitable or unresponsive to neuromodulation and still warrant further treatment. However, the long-term outcome may not be as good as with other treatments mentioned above.

Interventional Therapies for Chronic Low Back Pain: A Focused Review (Efficacy and Outcomes)

CONTEXT

Lower back pain is considered to be one of the most common complaints that brings a patient to a pain specialist. Several modalities in interventional pain management are known to be helpful to a patient with chronic low back pain. Proper diagnosis is required for appropriate intervention to provide optimal benefits. From simple trigger point injections for muscular pain to a highly complex intervention such as a spinal cord stimulator are very effective if chosen properly. The aim of this article is to provide the reader with a comprehensive reading for treatment of lower back pain using interventional modalities.

EVIDENCE ACQUISITION

Extensive search for published literature was carried out online using PubMed, Cochrane database and Embase for the material used in this manuscript. This article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images were prepared by and belong to the author.

RESULTS

This review article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images belong to the author. Although it is beyond the scope of this review article to include a very detailed description of each procedure along with complete references, a sincere attempt has been made to comprehensively cover this very complex and perplexing topic.

CONCLUSION

Lower back pain is a major healthcare issue and this review article will help educate the pain practitioners about the current evidence based treatment options.