Spinal Cord Stimulation Using High Frequency Electromagnetic Coupling (HF-EMC) Technology to Power an Implanted Neurostimulator With a Separate Receiver for Treating Chronic Back and Leg Pain: A Retrospective Study.

Abstract

Background: Chronic low back and lower limb pain occurs in 13% of Americans, and is the leading cause of disability. Patients with this condition have a reduced quality of life, have mental health disorders, and cognitive disfunction. While back pain alone is difficult to manage, back pain with associated leg pain results in further reduced outcomes. Spinal cord stimulation (SCS) is a minimally invasive therapy that has been used for a variety of chronic pain disorders when conservative management strategies have failed. The therapy is appealing because of its ability to provide long-term relief at a reduced cost and it has low rates of serious adverse events.

Objective: The objective of this retrospective study was to examine the safety and efficacy of the Freedom® Spinal Cord Stimulator System for treating patients who have chronic bilateral back and leg pain.

Study design: This retrospective study included 32 patients who received a permanent Freedom® SCS System to treat their chronic bilateral back and leg pain due to nerve compression due to complex regional pain syndrome (CRPS) Type I and/or II. A retrospective chart review was conducted to assess baseline and follow-up Verbal Rating Scale (VRS) pain scores as well as  complications.

Setting: This study was conducted at a single center in the United States.

Methods: The data were retrospectively collected from patients' medical records. Pain was assessed using the 11-point VRS scores; these scores were collected at baseline, post-trial, 6 months post-implantation, and 12 months post-implantation. Adverse events were reported descriptively and classified as serious or nonserious and either related or nonrelated to the implantation.

Results: The post-trial VRS scores for the 32 patients  were reduced by 73% (P < 0.001). At 6 months post-implantation, the VRS scores were reduced by 71% (P < 0.001) for 30 patients and at 12 months by 74% (P < 0.001) for 19 patients. No adverse events were reported.

Limitations: Our study's retrospective design limited us to the data available in the patients' charts.

Conclusion: The Freedom SCS System is an effective and safe therapy for treating patients with chronic back and leg pain that is resistant to conservative therapy due to nerve compression and CRPS Type I and/or II. These types of patients often report aggravation of symptoms with surgery. Minimal invasive surgery should decrease the chance of extra symptoms.