Counting the Costs: Case Management Implications of Spinal Cord Stimulation Treatment for Failed Back Surgery Syndrome

Physical Therapy Utilization After Single-level Posterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Characterize physical therapy (PT) utilization following single-level posterior lumbar fusion (PLF).

SUMMARY OF BACKGROUND DATA

PLF is a common procedure that is increasing in frequency. After such surgeries, PT may be considered to facilitate mobilization and return to activities. However, the usage of such therapy has not been well-characterized in the literature.

MATERIALS AND METHODS

Patients undergoing single-level PLF were identified from the 2010 to 2021 PearlDiver administrative database. These patients were stratified based on usage of therapy, home versus outpatient therapy, and timing of therapy within the year after surgery. To determine predictors of therapy, patient characteristics were determined and multivariable regressions were performed.

RESULTS

A total of 213,240 patients undergoing single-level PLF were identified, of which therapy was done in the year after surgery for 63,231 (29.0%, of which home therapy accounted for 16.5% of therapy visits). Of those who utilized PT, the average number of visits was 10.6±10.6. Home therapy peaked within the first month after surgery and outpatient therapy peaked at month two. Factors associated with any PT following PLF in decreasing odds ratio (OR) were having commercial insurance (OR: 1.68), being from the Northeast (OR: 1.41), age (OR: 1.13 for 70+ of age) female sex (OR: 1.09), and ECI (OR: 1.04 per point) ( P <0.001 for all). Of those who received therapy, factors associated with home PT utilization were being from the Northeast (OR: 2.55), age (OR: 1.91 for 70+ of age), Medicaid insurance (OR: 1.48), female sex (OR: 1.39), and interbody fusion (OR:1.07) ( P <0.001 for all).

CONCLUSIONS

After single-level PLF, the minority of patients received home or outpatient PT. Of those who did, there was significant variation in the number of visits, with nonmedical factors such as insurance plan and geographic region being strongly associated suggesting room for more consistent practice patterns.

LEVEL OF EVIDENCE

Level 3.

Healthcare Utilization (HCU) Reduction with High-Frequency (10 kHz) Spinal Cord Stimulation (SCS) Therapy

Spinal cord stimulation (SCS) is a well-established treatment for patients with chronic pain. With increasing healthcare costs, it is important to determine the benefits of SCS in healthcare utilization (HCU). This retrospective, single-center observational study involved 160 subjects who underwent implantation of a high-frequency (10 kHz) SCS device. We focused on assessing trends in HCU by measuring opioid consumption in morphine milligram equivalents (MME), as well as monitoring emergency department (ED) and office visits for interventional pain procedures during the 12-month period preceding and following the SCS implant. Our results revealed a statistically significant reduction in HCU in all domains assessed. The mean MME was 51.05 and 26.52 pre- and post-implant, respectively. There was a 24.53 MME overall decrease and a mean of 78.2% statistically significant dose reduction (p < 0.0001). Of these, 91.5% reached a minimally clinically important difference (MCID) in opioid reduction. Similarly, we found a statistically significant (p < 0.01) decrease in ED visits, with a mean of 0.12 pre- and 0.03 post-implant, and a decrease in office visits for interventional pain procedures from a 1.39 pre- to 0.28 post-10 kHz SCS implant, representing a 1.11 statistically significant (p < 0.0001) mean reduction. Our study reports the largest cohort of real-world data published to date analyzing HCU trends with 10 kHz SCS for multiple pain etiologies. Furthermore, this is the first and only study evaluating HCU trends with 10 kHz SCS by assessing opioid use, ED visits, and outpatient visits for interventional pain procedures collectively. Preceding studies have individually investigated these outcomes, consistently yielding positive results comparable to our findings.

Short-Term Health Care Costs of High-Frequency Spinal Cord Stimulation for the Treatment of Postsurgical Persistent Spinal Pain Syndrome

OBJECTIVE

High-frequency spinal cord stimulation (HF-SCS) is a treatment option for postsurgical persistent spinal pain syndrome (type 2 PSPS). We aimed to determine the health care costs associated with this therapy in a nationwide cohort.

MATERIALS AND METHODS

IBM Marketscan® Research Databases were used to identify patients who underwent HF-SCS implantation from 2016 to 2019. Inclusion criteria included prior spine surgery or diagnoses of PSPS or postlaminectomy pain syndrome any time within the two years before implantation. Inpatient and outpatient service costs, medication costs, and out-of-pocket costs were collected six months before implantation (baseline) and one, three, and six months after implantation. The six-month explant rate was calculated. Costs were compared between baseline and six months after implant via Wilcoxon sign rank test.

RESULTS

In total, 332 patients were included. At baseline, patients incurred median total costs of $15,393 (Q1: $9,266, Q3: $26,216), whereas the postimplant median total costs excluding device acquisition were $727 (Q1: $309, Q3: $1,765) at one month, $2,840 (Q1: $1,170, Q3: $6,026) at three months, and $6,380 (Q1: $2,805, Q3: $12,637) at six months. The average total cost was reduced from $21,410 (SD $21,230) from baseline to $14,312 (SD $25,687) at six months after implant for an average reduction of $7,237 (95% CI = $3212-$10,777, p < 0.001). The median device acquisition costs were $42,937 (Q1: $30,102, Q3: $65,880). The explant rate within six months was 3.4% (8/234).

CONCLUSIONS

HF-SCS for PSPS was associated with significant decreases in total health care costs and offsets acquisition costs within 2.4 years. With the rising incidence of PSPS, it will be critical to use clinically effective and cost-efficient therapies for treatment.

Neuromodulation for chronic pain

Neuromodulation is an expanding area of pain medicine that incorporates an array of non-invasive, minimally invasive, and surgical electrical therapies. In this Series paper, we focus on spinal cord stimulation (SCS) therapies discussed within the framework of other invasive, minimally invasive, and non-invasive neuromodulation therapies. These therapies include deep brain and motor cortex stimulation, peripheral nerve stimulation, and the non-invasive treatments of repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous electrical nerve stimulation. SCS methods with electrical variables that differ from traditional SCS have been approved. Although methods devoid of paraesthesias (eg, high frequency) should theoretically allow for placebo-controlled trials, few have been done. There is low-to-moderate quality evidence that SCS is superior to reoperation or conventional medical management for failed back surgery syndrome, and conflicting evidence as to the superiority of traditional SCS over sham stimulation or between different SCS modalities. Peripheral nerve stimulation technologies have also undergone rapid development and become less invasive, including many that are placed percutaneously. There is low-to-moderate quality evidence that peripheral nerve stimulation is effective for neuropathic pain in an extremity, low quality evidence that it is effective for back pain with or without leg pain, and conflicting evidence that it can prevent migraines. In the USA and many areas in Europe, deep brain and motor cortex stimulation are not approved for chronic pain, but are used off-label for refractory cases. Overall, there is mixed evidence supporting brain stimulation, with most sham-controlled trials yielding negative findings. Regarding non-invasive modalities, there is moderate quality evidence that repetitive transcranial magnetic stimulation does not provide meaningful benefit for chronic pain in general, but conflicting evidence regarding pain relief for neuropathic pain and headaches. For transcranial direct current stimulation, there is low-quality evidence supporting its benefit for chronic pain, but conflicting evidence regarding a small treatment effect for neuropathic pain and headaches. For transcutaneous electrical nerve stimulation, there is low-quality evidence that it is superior to sham or no treatment for neuropathic pain, but conflicting evidence for non-neuropathic pain. Future research should focus on better evaluating the short-term and long-term effectiveness of all neuromodulation modalities and whether they decrease health-care use, and on refining selection criteria and treatment variables.

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.

Clinical effectiveness of caudal epidural pulsed radiofrequency stimulation in managing refractory chronic leg pain in patients with postlumbar surgery syndrome

BACKGROUND AND OBJECTIVE

We evaluated the effect of caudal epidural pulsed radiofrequency stimulation in patients with chronic lumbosacral radicular pain due to postlumbar surgery syndrome who were unresponsive to at least two epidural steroid injections through the interlaminar, transforaminal, or caudal route.

METHODS

We recruited 25 patients with chronic persistent radicular pain in one or both legs (⩾ 4 on the Numeric Rating Scale [NRS]) despite spinal surgery. They were unresponsive to at least two epidural steroid injections. We retrospectively conducted this study. Electrode needles were placed into the epidural space (S2-3 intervertebral level) through the sacral hiatus, and pulsed radiofrequency stimulation was administered. The outcomes were evaluated using the NRS scores for radicular pain before treatment and 1-3 months after treatment. Successful pain relief was defined as a ⩾ 50% reduction in the scores at 3 months after treatment.

RESULTS

The pain scores changed significantly over time (p< 0.001): pretreatment, 4.9 ± 0.9; 1 month, 3.6 ± 1.4; 2 months, 3.8 ± 1.4; and 3 months, 3.9 ± 1.4. At 1, 2, and 3 months after pulsed radiofrequency (PRF) procedure, the NRS scores were significantly reduced compared with the scores before the treatment. Eight patients (32%) reported successful pain relief at 3 months after treatment.

CONCLUSIONS

Although only 32% of the patients with postlumbar surgery syndrome showed successful pain relief after treatment, the result is encouraging because we recruited only patients unresponsive to repeated epidural steroid injections.

Trial Design and Endpoint Evaluation in Clinical Studies Addressing Chronic Back Pain

STUDY DESIGN

A review of the literature evaluating clinical trials of chronic back pain.

OBJECTIVE

To assist physicians in assessing the quality of clinical trial data to make the most informed treatment decisions.

SUMMARY OF BACKGROUND DATA

Chronic pain is a tremendous public health issue, affecting close to 100 million adults in the United States, and costs the American people billions of dollars. One traditional treatment approach, the long-term use of opiate medications, has recently come under intense scrutiny for problems with complications, diversion, abuse, addiction, and lack of efficacy. In addition, the Centers for Disease Control and Prevention has recognized that overprescribing opiates has enabled an overdose crisis, and written guidelines that are intended to limit their use. It is for this reason that physicians must have a comprehensive understanding of the range of drug-free alternative therapies available and have the tools needed to rigorously evaluate the chronic pain literature so they can make appropriate treatment decisions.

METHODS

An evaluation of how clinical trials are designed and ranked, outcome measures, and costs for a variety of therapies is necessary to determine which treatment option is the most efficacious for an individual patient.

RESULTS

Clinical trial data demonstrate that spinal cord stimulation (SCS) is a safe and effective treatment option for many types of chronic pain, including back pain. The last 10 years has brought tremendous advances in the field of neuromodulation. Today, several treatment modalities exist for SCS requiring the physician to be able to critically evaluate and interpret the literature and determine which modality has the strongest evidence. When evaluating clinical trial data of patients with chronic back pain, emphasis must be placed on well designed, randomized controlled trials with long-term follow-up producing level I evidence. These data are obtained in a rigorous manner and are likely to have less bias when compared with lower level studies.

CONCLUSION

The level I studies performed to date have provided evidence that treatment with SCS results in sustainable pain reduction and improvements in scores measuring quality of life and patient functioning in those patients with chronic intractable back pain.

LEVEL OF EVIDENCE

5.

Cost-Effectiveness Data Regarding Spinal Cord Stimulation for Low Back Pain

STUDY DESIGN

Review of published literature pertaining to spinal cord stimulation (SCS) cost data analysis.

OBJECTIVE

To acquire, organize, and succinctly summarize the available literature regarding the costs associated with, and the cost-effectiveness of, SCS.

SUMMARY OF BACKGROUND DATA

Chronic back and limb pain is a pervasive complaint in modern society, with estimated annual costs of medical care greater than $100 billion. The traditional standard medical management with or without intermittent surgical decompression/fusion has been plagued by high costs and inconsistent results, leading to poor patient satisfaction and functional outcome, and questions from policy makers regarding use of limited healthcare resources. Neuromodulation techniques, including SCS have recently become more common in the treatment of chronic back/leg pain, with clinical studies showing a high degree of efficacy in alleviating otherwise intractable pain. Given the relatively high upfront costs associated with the hardware and implantation, policy makers have, however, questioned their use in the framework of cost-containment and resource utilization. We reviewed the available literature summarizing cost data of SCS in chronic back and limb pain, as an understanding of these data will be vital to justify continued payment for this expensive, but often very effective, treatment modality.

METHODS

We performed a PubMed literature search utilizing the following terms: "spinal cord stimulation," "SCS," "financial," "cost," "cost-effectiveness," and "cost-utility." All studies published in English and containing complete or partial cost evaluations of SCS for chronic back and limb pain were included.

RESULTS

The search revealed 21 studies that evaluated cost data, with or without outcomes analysis and cost-utility analysis, for patients with chronic back and limb pain. The overwhelming majority of data presented shows that SCS is not only an effective treatment option for these patients, but also represents cost savings and efficient use of healthcare resources relative to current standards of care. Although not all studies performed cost-utility analyses, those that did tended to show SCS falling well within accepted thresholds of "willingness-to-pay" on the part of third-party payers. That being said, the articles included in this review were almost all small, retrospective, single-institution studies. In addition, many of them relied on modeling for their analyses, and published literature values for cost and/or outcomes data rather than prospectively collected patient data. Although the data presented in this review are encouraging, it should serve as a foundation for a thorough, prospective, cost-utility analysis of SCS in chronic back and limb pain so that the role of this important treatment modality may be cemented in the treatment paradigm for these patients without questions from third-party payers.

CONCLUSION

The large majority of data covering costs of SCS argue in favor of the cost-effectiveness of this treatment modality for chronic neuropathic pain, especially in comparison to reoperation and medical management. Although most of the higher-quality evidence is relatively short-term, clinical experience with the durability of treatment benefit of SCS in these patients is promising. Given the pushback regarding high upfront costs of implantation, longer-term, prospective, randomized studies evaluating this topic will be important to help maintain third-party payer reimbursements for SCS.

LEVEL OF EVIDENCE

5.

[SCS as a treatment option for failed back surgery syndrome]

Unfortunately, 10-40 % of patients still experience pain after spinal surgery. There are many reasons for the patients' complaints. If no identifiable cause, such as a recurrent disc herniation, is visible, this is referred to as failed back surgery syndrome. However, this definition includes a variety of possible underlying causes of the pain, which result in just as many different therapeutic approaches. In addition to pharmacological, behavioral and physical therapy, also neuromodulation techniques can be offered; the best known method is spinal cord stimulation (SCS). The following article describes evidence-based studies with regard to the beneficial treatment of failed back surgery syndrome with conventional tonic SCS and new developments in spinal cord stimulation addressing the treatment of chronic refractory back pain.

Spinal cord stimulation modulates cerebral neurobiology: a proton magnetic resonance spectroscopy study

INTRODUCTION

Although spinal cord stimulation (SCS) is a widely used treatment for chronic neuropathic pain secondary to spinal surgery, little is known about the underlying physiological mechanisms.

METHODS

The primary aim of this study is to investigate the neural substrate underlying short-term SCS by means of (1)H MR spectroscopy with short echo time, in 20 patients with failed back surgery syndrome.

RESULTS

Marked increase of γ-aminobutyric acid (GABA) and decrease in glucose in the ipsilateral thalamus were found between baseline situation without SCS and after 9' of SCS, indicating the key role of the ipsilateral thalamus as a mediator of chronic neuropathic pain. In addition, this study also showed a progressive decrease in glucose in the ipsilateral thalamus over time, which is in line with the findings of previous studies reporting deactivation in the ipsilateral thalamic region.

CONCLUSIONS

The observation of GABA increase and glucose decrease over time in the ipsilateral thalamus may be the causal mechanism of the pain relief due to SCS or an epiphenomenon.

Dorsal column stimulator applications

Background:

Spinal cord stimulation (SCS) has been used to treat neuropathic pain since 1967. Following that, technological progress, among other advances, helped SCS become an effective tool to reduce pain.

Methods:

This article is a non-systematic review of the mechanism of action, indications, results, programming parameters, complications, and cost-effectiveness of SCS.

Results:

In spite of the existence of several studies that try to prove the mechanism of action of SCS, it still remains unknown. The mechanism of action of SCS would be based on the antidromic activation of the dorsal column fibers, which activate the inhibitory interneurons within the dorsal horn. At present, the indications of SCS are being revised constantly, while new applications are being proposed and researched worldwide. Failed back surgery syndrome (FBSS) is the most common indication for SCS, whereas, the complex regional pain syndrome (CRPS) is the second one. Also, this technique is useful in patients with refractory angina and critical limb ischemia, in whom surgical or endovascular treatment cannot be performed. Further indications may be phantom limb pain, chronic intractable pain located in the head, face, neck, or upper extremities, spinal lumbar stenosis in patients who are not surgical candidates, and others.

Conclusion:

Spinal cord stimulation is a useful tool for neuromodulation, if an accurate patient selection is carried out prior, which should include a trial period. Undoubtedly, this proper selection and a better knowledge of its underlying mechanisms of action, will allow this cutting edge technique to be more acceptable among pain physicians.

Metal-induced artifacts in MRI

OBJECTIVE

The purpose of this article is to review some of the basic principles of imaging and how metal-induced susceptibility artifacts originate in MR images. We will describe common ways to reduce or modify artifacts using readily available imaging techniques, and we will discuss some advanced methods to correct readout-direction and slice-direction artifacts.

CONCLUSION

The presence of metallic implants in MRI can cause substantial image artifacts, including signal loss, failure of fat suppression, geometric distortion, and bright pile-up artifacts. These cause large resonant frequency changes and failure of many MRI mechanisms. Careful parameter and pulse sequence selections can avoid or reduce artifacts, although more advanced imaging methods offer further imaging improvements.