Spinal cord stimulation failure: evaluation of factors underlying hardware explantation

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Spinal cord stimulation has been shown to improve pain relief and reduce narcotic analgesic use in cases of complex refractory pain syndromes. However, a subset of patients ultimately undergoes removal of the spinal cord stimulator (SCS) system, presumably because of surgical complications or poor efficacy. This retrospective study addresses the paucity of evidence regarding risk factors and underlying causes of spinal cord stimulation failures that necessitate this explantation.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>In this retrospective single-center review, 129 patients underwent explantation of SCS hardware during a 9-year period (2005–2013) following initial placement at the authors’ institution or elsewhere. Medical history, including indication of implantation, device characteristics, revision history, and reported reasons for removal of hardware, were reviewed.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>The 74 (57%) women and 55 (43%) men were a median of 49 years old (IQR 41–61 years) at explantation; the median time to explantation was 20 months (IQR 7.5–45.5 months). Thoracic or upper lumbar leads were placed in 89.9% of patients primarily for the diagnosis of postsurgical failed–back surgery syndrome (70.5%), chronic regional pain syndrome (14.7%), and neuropathic pain (8.5%). More than half of patients were legally disabled. Initial postoperative reduction in pain was reported in 81% of patients, and 37.8% returned to work. Among 15 patients with acute postsurgical complications (12 infections, 2 hemorrhages, 1 immediate paraplegia), the median time to removal was 2 months. Primary reasons for hardware removal were lack of stimulation efficacy (81%), electrode failure due to migration (14%), and allergic reactions to implanted hardware in 2 patients. The 72 patients who underwent formal psychiatric evaluation before implantation were affected by high rates of major depression (64%), anxiety (34%), posttraumatic stress disorder (PTSD) (12%), drug or alcohol abuse (12%), and physical or sexual abuse (22%).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>The authors’ findings provide insight regarding the mechanisms of spinal cord stimulation failure that resulted in total removal of the implanted system. The relationship between spinal cord stimulation failure and certain psychiatric disorders, such as PTSD, depression, and anxiety, is highlighted. Ultimately, this work may shed light on potential avenues to reduce morbidity and improve patient outcomes.</jats:p></jats:sec>

Direct Peripheral Nerve Stimulation for the Treatment of Complex Regional Pain Syndrome: A 30-Year Review

“…If present, anxiety and depression were the most common. Patel et al demonstrated a correlation between SCS failure and certain psychiatric disorders, including PTSD, depression, and anxiety that resulted in system removal (30). All of our patients underwent preoperative psychological testing.…”

Electrochemical Skin Conductance Alterations during Spinal Cord Stimulation: An Experimental Study

“…If this is the case, SCS system explantation is often performed and a substantial proportion of these explants happens before 2.25 years of SCS treatment [63], the so-called "break even" point for SCS treatment when compared with conventional medical management [64]. Patel et al (2019) reviewed the reasons for SCS device explantation in a sample of 129 patients who were treated with SCS [65]. The median time to explantation was 20 months (IQR 7.5-45.5 months), with the primary reason being a lack of efficacy (80.6%) [65].…”

“…Patel et al (2019) reviewed the reasons for SCS device explantation in a sample of 129 patients who were treated with SCS [65]. The median time to explantation was 20 months (IQR 7.5-45.5 months), with the primary reason being a lack of efficacy (80.6%) [65]. Only patients who had not yet undergone a device explantation were eligible in this study.…”

Postoperative Infections Associated With Prolonged Spinal Cord Stimulation Trial Duration (PROMISE RCT)

“…Infection is an inherent risk with any invasive procedure, particularly when a foreign body is implanted; it occurred in 2.45–5% of cases in large SCS series and meta‐analyses and in up to 14% in small series . Infection is the most common acute postsurgical SCS complication leading to removal of SCS equipment and, as removal is generally followed by replacement of the entire system, is one of the more costly complications.…”