Injury and Liability Associated with Implantable Devices for Chronic Pain

Trends in spinal cord stimulation utilization: change, growth and implications for the future

Chronic pain impacts more than 100 million Americans and has a significant impact on the economy and quality of life. Spinal cord stimulation (SCS) has demonstrated efficacy in managing a growing number of chronic pain conditions. This in combination with an increasing number of physicians trained in SCS placement has produced significant changes in utilization, expense and sites of service related to SCS. In particular, there has been a large increase in SCS placement by non-surgeons, use of percutaneous leads and performance in ambulatory surgery centers instead of inpatient settings. There are also notable differences in SCS use related to age, race, insurance coverage and geography. There is a large potential market and use of these therapies is predicted to grow from $2.41 billion in 2020 to $4.12 billion US dollars globally by 2027. At the same time, there is increasing scrutiny around utilization of this therapy related to cost, complications, long-term efficacy and explant rates that has the potential to impact access to this therapy in the future. We must examine our indications, technique and management to optimize outcomes and utilization of SCS going forward.

The American Society of Pain and Neuroscience (ASPN) Evidence-Based Clinical Guideline of Interventional Treatments for Low Back Pain

Introduction

Painful lumbar spinal disorders represent a leading cause of disability in the US and worldwide. Interventional treatments for lumbar disorders are an effective treatment for the pain and disability from low back pain. Although many established and emerging interventional procedures are currently available, there exists a need for a defined guideline for their appropriateness, effectiveness, and safety.

Objective

The ASPN Back Guideline was developed to provide clinicians the most comprehensive review of interventional treatments for lower back disorders. Clinicians should utilize the ASPN Back Guideline to evaluate the quality of the literature, safety, and efficacy of interventional treatments for lower back disorders.

Methods

The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations. Experts from the fields of Anesthesiology, Physiatry, Neurology, Neurosurgery, Radiology, and Pain Psychology developed the ASPN Back Guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Scopus, and meeting abstracts to identify and compile the evidence (per section) for back-related pain. Search words were selected based upon the section represented. Identified peer-reviewed literature was critiqued using United States Preventive Services Task Force (USPSTF) criteria and consensus points are presented.

Results

After a comprehensive review and analysis of the available evidence, the ASPN Back Guideline group was able to rate the literature and provide therapy grades to each of the most commonly available interventional treatments for low back pain.

Conclusion

The ASPN Back Guideline represents the first comprehensive analysis and grading of the existing and emerging interventional treatments available for low back pain. This will be a living document which will be periodically updated to the current standard of care based on the available evidence within peer-reviewed literature.

Haematoma, abscess or meningitis after neuraxial anaesthesia in the USA and the Netherlands: A closed claims analysis

BACKGROUND

Severe complications after neuraxial anaesthesia are rare but potentially devastating.

OBJECTIVE

We aimed to identify characteristics and preventable causes of haematoma, abscess or meningitis after neuraxial anaesthesia.

DESIGN

Observational study, closed claims analysis.

SETTING

Closed anaesthesia malpractice claims from the USA and the Netherlands were examined from 2007 until 2017.

PATIENTS

Claims of patients with haematoma (n = 41), abscess (n = 18) or meningitis (n = 14) associated with neuraxial anaesthesia for labour, acute and chronic pain that initiated and closed between 2007 and 2017 were included. There were no exclusions.

MAIN OUTCOME MEASURES

We analysed potential preventable causes in patient-related, neuraxial procedure-related, treatment-related and legal characteristics of these complications.

RESULTS

Patients experiencing spinal haematoma were predominantly above 60 years of age and using antihaemostatic medication, whereas patients with abscess or meningitis were middle-aged, relatively healthy and more often involved in emergency interventions. Potential preventable causes of unfavourable sequelae constituted errors in timing/prescription of antihaemostatic medication (10 claims, 14%), unsterile procedures (n = 10, 14%) and delay in diagnosis/treatment of the complication (n = 18, 25%). The number of claims resulting in payment was similar between countries (USA n = 15, 38% vs. the Netherlands n = 17, 52%; P = 0.25). The median indemnity payment, which the patient received varied widely between the USA (&OV0556;285 488, n = 14) and the Netherlands (&OV0556;31 031, n = 17) (P = 0.004). However, the considerable differences in legal systems and administration of expenses between countries may make meaningful comparison of indemnity payments inappropriate.

CONCLUSIONS

Claims of spinal haematoma were often related to errors in antihaemostatic medication and delay in diagnosis and/or treatment. Spinal abscess claims were related to emergency interventions and lack of sterility. We wish to highlight these potential preventable causes, both when performing the neuraxial procedure and during postprocedural care of patients.

Spinal Cord Stimulator Explant and Revision Complicated by Syrinx Formation: A Case Report and Literature Review

Spinal cord stimulation (SCS) has been shown to be a safe, effective, and drug-free treatment option for many chronic pain conditions including refractory low back pain. The most commonly reported complication of SCS is equipment failure. We report a case of spinal cord injury (SCI) during SCS explant and revision.

This 61-year-old female veteran complained of intermittent shock-like sensations 3-4 times a week for three months prior to her clinic visit. The device was initially implanted in 2009 secondary to neurogenic claudication with appropriate relief. The battery was replaced in 2015. Pain Management Service referred the patient to neurosurgery for replacement of the original SCS unit. Immediately following surgery she complained of severe left lower extremity pain concentrated in the medial thigh radiating into the groin and buttock. She also complained of pain, weakness and numbness in both legs (left more than right). Magnetic resonance imaging (MRI) revealed an edematous area in the left spinal cord between T11-T12. The patient was placed on steroids, ketamine infusion for pain control, and MRI the next day showed slight improvement of the edema and she was discharged home. Follow-up MRI two months later revealed mild diminution in the size of the cord edema. Her pre-operative shock-like sensations had not returned.

While rare, spinal cord injury can occur and should be identified and managed expeditiously. Our case here reports for the first time an association between SCS explant/revision and syrinx formation.

Spinal Cord Stimulation Infection Rate and Incremental Annual Expenditures: Results From a United States Payer Database

OBJECTIVES

Surgical site infections (SSIs) result in significant negative clinical and economic outcomes. The objective of this study is to estimate annual health expenditures associated with spinal cord stimulation (SCS)-related infections.

MATERIALS AND METHODS

Data from the Truven MarketScan® databases were used to identify patients with an SCS implant (2009-2014) and a continuous health plan enrollment for at least 12-months before and after implant (index date). Annual expenditures were estimated for patients with a device-related infection vs. those without infection since index date. A generalized linear model estimated annual expenditures attributable to device-related infection. Multivariable expenditure models were conducted separately for patients in initial and replacement groups, controlling for demographics, comorbidities, and clinical characteristics.

RESULTS

The study included 6615 patients. Multivariable expenditure models revealed that patients with infection have higher annual expenditures than patients without infection. Estimated incremental annual healthcare expenditures for patients with an infection were $59,716 (95% CI: $48,965-$69,480) for initial implanted patients and $64,833 (95% CI: $37,377-$86,519) for replacement patients. Only 26% of patients who were explanted for infection underwent a reimplant.

CONCLUSIONS

These results show the substantial expenditure burden associated with an SCS-related infection. Management of SCS-related infection is important from both clinical and economic standpoints. The economic and clinical data presented here reinforce the need for additional research and strategies for healthcare providers to minimize SCS infections. Future economic research is needed to further define the specific economic cost drivers associated with the extensive expenditure burden.

Spinal Cord Stimulation Infection Rate and Risk Factors: Results From a United States Payer Database

Objective

Surgical site infections can cause negative clinical and economic outcomes. A recent international survey on Spinal Cord Stimulation (SCS) infection control practices demonstrated low compliance with evidence‐based guidelines. This study defines infection rate for SCS implants and identifies infection risk factors.

Materials and Methods

A retrospective analysis of the MarketScan® Databases identified patients with SCS implant (2009–2014) and continuous health plan enrollment for ≥12‐months (12 m) preimplant. For logistic regression analysis, patients were enrolled for 12 m postimplant. Kaplan–Meier and Cox Proportional Hazard survival analyses assessed time to infection, with infection rate reported at 12 m postimplant. Logistic regression characterized risk factors based on demographics, comorbidities, and clinical characteristics.

Results

In the logistic regression (n = 6615), 12 m device‐related infection rate was 3.11%. Infection risk factors included peripheral vascular disease (OR, 1.784; 95% CI: 1.011–3.149; p = 0.0457) and infection in 12 m before implant (OR, 1.518; 95% CI: 1.022–2.254; p = 0.0386). The odds of patients experiencing an infection decreased by 3.2% with each additional year of age (OR, 0.968; 95% CI: 0.952–0.984; p < 0.0001). Survival analysis (n = 13,214) identified prior infection (HR, 1.770; 95% CI: 1.342–2.336; p < 0.0001) as a risk factor. Infection was less likely in older patients (HR, 0.974; 95% CI: 0.962–0.986; p < 0.0001). Expected risk factors including obesity, diabetes, and smoking were not identified as risk factors in this analysis. There was no significant difference between infection rate for initial and replacement implants.

Conclusions

The 3.11% SCS‐related infection rate within 12 m of implant emphasizes the need for improved infection control practices. Research is needed to limit SCS infections in younger patients and those with infection history.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management

INTRODUCTION

The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique.

METHODS

The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations.

RESULTS

The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices.

CONCLUSION

Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

The Neurostimulation Appropriateness Consensus Committee (NACC) Safety Guidelines for the Reduction of Severe Neurological Injury

INTRODUCTION

Neurostimulation involves the implantation of devices to stimulate the brain, spinal cord, or peripheral or cranial nerves for the purpose of modulating the neural activity of the targeted structures to achieve specific therapeutic effects. Surgical placement of neurostimulation devices is associated with risks of neurologic injury, as well as possible sequelae from the local or systemic effects of the intervention. The goal of the Neurostimulation Appropriateness Consensus Committee (NACC) is to improve the safety of neurostimulation.

METHODS

The International Neuromodulation Society (INS) is dedicated to improving neurostimulation efficacy and patient safety. Over the past two decades the INS has established a process to use best evidence to improve care. This article updates work published by the NACC in 2014. NACC authors were chosen based on nomination to the INS executive board and were selected based on publications, academic acumen, international impact, and diversity. In areas in which evidence was lacking, the NACC used expert opinion to reach consensus.

RESULTS

The INS has developed recommendations that when properly utilized should improve patient safety and reduce the risk of injury and associated complications with implantable devices.

CONCLUSIONS

On behalf of INS, the NACC has published recommendations intended to reduce the risk of neurological injuries and complications while implanting stimulators.