Lies, Damn Lies, and Statistic: A Commentary

Real-world outcomes in spinal cord stimulation: predictors of reported effect and explantation using a comprehensive registry-based approach

Introduction

Despite advancements in implanted hardware and development of novel stimulation paradigms in Spinal Cord Stimulation (SCS), real world evidence suggests a large variation in patient reported outcomes and a proportion of patients are later explanted due to loss of analgesia. Possible predictors for outcome have been explored in smaller short-term evaluations, but few clinically applicable robust measures for long term outcome have emerged.

Methods

We performed a comprehensive retrospective study based on an assembled patient-level aggregated database from multiple local and national registries in Sweden. Variables associated with risk of explantation (due to insufficient analgesia) and analgesic effect was analyzed using a Cox regression analysis and an ordered logit regression model, respectively.

Results

We found the accumulated risk of explantation due to loss of analgesia to be 10% and 21% at two and ten years follow up, respectively. The use of 10 kHz spinal cord stimulation (compared with Tonic waveform; p = 0.003), and being 60 years or older (reference 18-40 years; p = 0.003) were associated with an increased risk of explantation.At a mean follow up at 1 year, 48% of patients reported a pain intensity reduction from baseline of at least 30%. Secondary (p = 0.030) and post-secondary (p = 0.001) education (compared with primary education) was associated with an increased probability of successful patient reported outcomes.

Conclusion

This study suggests that a higher educational level and being employed are associated with successful treatment outcome in patients with chronic pain treated with SCS in Sweden.

Review of Efficacy and Safety of Spinal Cord Stimulation in Veterans

OBJECTIVES

Spinal cord stimulation (SCS) has been shown to be an effective and safe option to treat patients with intractable pain in the general population. Our study examined the experience of US veterans with SCS.

METHODS

We reviewed electronic health records and conducted phone interviews with 65 veterans who had SCS from 2008 to 2020 at the Southeastern Louisiana Veterans Health Care System (SLVHCS). Our primary outcome measure was veteran would recommend SCS to peers. Secondary outcomes were improvements in activities of daily living and ability to decrease opioid pain medications.

RESULTS

A majority (77%) of veterans recommended SCS to their peers. Statistical difference was seen in 16 of 18 categories of activities of daily living based on the Pain Outcomes Questionnaire. No permanent neurologic deficits or deaths were associated with SCS use. There were no neurological sequelae. Three patients (5%) developed skin dehiscence postimplant and were treated with explant surgery but all were eager to get a new SCS implanted.

CONCLUSION

Veterans at SLVHCS were satisfied with their experience using SCS and few experienced adverse effects.