High Explantation Risks With Long-Term Use of Different Spinal Cord Stimulation Devices

The long-term explantation risks associated with spinal cord stimulation (SCS) and dorsal root ganglion (DRG) for the management of chronic pain are high and vary based on the type of stimulation provided, according to results of a retrospective observational study published in Regional Anesthesia & Pain Medicine.

Researchers evaluated selected patients who, after 2 to 3 weeks of test trials, underwent permanent implantation of SCS or DRG stimulation systems at Sahlgrenska University Hospital, in Gothenburg, Sweden, between January 2012 and December 2022. They sought to assess 5- and 10-year explantation risks and examine causes of explantation associated with different SCS and DRG stimulation devices. Differences between manufacturers in 5-year explantation risks were also assessed by univariable and multivariable Cox regression analyses, to adjust for other possible variables affecting explantation.

During the study period, 400 patients were implanted with SCS devices. In this group, 37% of patients received devices from Boston Scientific, 27.5% from Medtronic, 22.5% from Nevro, 11.8% from Abbott, and 1.3% from Saluda. Among 47 patients implanted with Abbott devices, 34% received a system for DRG stimulation. The ean (SD) age at implantation was 51.8 (12.5) years, and 58.8% of patients were women. The most common indication for implantation was persistent spinal pain syndrome type 2 (61.0%), followed by peripheral neuralgia (11.8%) and complex regional pain syndrome (10.3%).

Across the study period, 24% of patients had their devices explanted; median time to explantation was 26 months. Reasons for explantation varied, with 55.2% due to diminished pain relief, 17.7% related to magnetic resonance imaging requirements, and 8.3% due to infection — which corresponded to 13%, 4%, and 2% of the 400 implantations, respectively. Among the cases of device explantation, 72 were therapy-ending. Regarding the 24 patients whose devices were reimplanted, 63% were switched to a device from a different manufacturer. The cumulative explantation risk across all manufacturers was 17% at 3 years, 23% at 5 years, and 38% at 10 years. Regarding explantation due to diminished pain relief, the risks were 10%, 14%, and 23%, respectively, over the 3-, 5-, and 10-years periods.

The 5-year explantation risk for any reason varied across manufacturers — 15% for Boston Scientific, 19% for Nevro, 29% for Medtronic, and 32% for Abbott — but these differences in risk were not statistically significant. In a regression analysis for explantation due to diminished pain relief, however, a multivariable analysis indicated a higher risk for Medtronic devices (hazard ratio [HR], 2.72; 95% CI, 1.18-6.3; P =.02) and DRG stimulation (HR, 6.73; 95% CI, 1.26-35.88; P =.03). A separate analysis of outcomes with 16 DRG stimulation devices — all implanted to treat conditions with focal neuropathic pain — showed explantation risks of 31% at 3 years, 38% at 5 years, and 63% at 10 years, with a median time to explantation of 21 months.

Limitations of this study include its retrospective design, which may have resulted in some missing medical records. Additionally, some variables besides those assessed (for example, opioid treatment and psychosocial factors) could have been associated with explantation. Finally, the researchers note that it may not be appropriate, in some cases, to compare traditional technologies (eg, Medtronic devices) with modern SCS systems.

The researchers concluded, “Although SCS and DRG stimulation are well-established and safe treatment for chronic pain, the long-term explantation risk remains high.” They added, “The difference between manufacturers highlights the importance of technological evolution for improving therapy outcomes. Increased stringency in patient selection and follow-up strategies, as well as further improvement of software and hardware in neuromodulation devices, could possibly reduce the long-term explantation rates.”

Disclosure: One study author reported affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Clinical Pain Advisor