Effect of Conventional Spinal Cord Stimulation on Serum Protein Profile in Patients With Persistent Spinal Pain Syndrome: A Case-Control Study.

BACKGROUND: Spinal cord stimulation (SCS) provides pain relief for most patients with persistent spinal pain syndrome type 2 (PSPS 2). Evidence is mounting on molecular changes induced by SCS as one of the mechanisms to explain pain improvement. We report the SCS effect on serum protein expression in vivo in patients with PSPS 2. MATERIALS AND METHODS: Serum proteins were identified and quantified using mass spectrometry. Proteins with significantly different expression among patients with PSPS 2 relative to controls, responders, and nonresponders to SCS, or significantly modulated by SCS relative to baseline, were identified. Those most correlated with the presence and time course of pain were selected using multivariate discriminant analysis. Bioinformatic tools were used to identify related biological processes. RESULTS: Thirty patients with PSPS 2, of whom 23 responded to SCS, were evaluated, together with 14 controls with no pain who also had undergone lumbar spinal surgery. A significant improvement in pain intensity, disability, and quality of life was recorded among responders. Five proteins differed significantly at baseline between patients with PSPS 2 and controls, with three proteins, mostly involved in immune processes and inflammation, being downregulated and two, mostly involved in vitamin metabolism, synaptic transmission, and restorative processes, being upregulated. In addition, four proteins, mostly related to immune processes and inflammation, decreased significantly, and three, mostly related to iron metabolism and containment of synaptic sprouting, increased significantly during SCS. CONCLUSION: This study identifies various biological processes that may underlie PSPS 2 pain and SCS therapeutic effects, including the modulation of neuroimmune response and inflammation, synaptic sprouting, vitamin and iron metabolism, and restorative processes.

Medical Device Related Pressure Injury in the Treatment of Chronic Pain: An Early Sign of Explantation in Suspected Infection.

BACKGROUND: Chronic back pain is a prevalent disease and has a high impact in daily life. Implantable devices (IDs) for chronic pain management include spinal cord stimulation (SCS) systems and intrathecal drug delivery (ITDD) pumps. The number of ITDD implants have increased exponentially in the last decade. The number of complications, such as infections, are also more prevalent. Infection management guidelines are needed to standarize our clinical practice and define protocols of explantation. OBJECTIVES: The primary outcome is to define the likelihood of device explantation regarding some covariates related to the patient, antibiotic therapy or surgerical procedures. The secondary outcome is to evaluate performance compared to the results published in the literature. STUDY DESIGN: Retrospective study. SETTING: Hospital General of Valencia. Valencia. Spain. METHODS: A retrospective study of 288 implantable device surgeries was conducted at the Hospital General Universitary of Valencia (Spain) from 1994 to 2015. Demographical and infection data were collected. We have followed the "guidelines for the diagnosis, prevention and management of implantable electronic cardiac device infection" due to the lack of a specific guideline in our field. RESULTS: Forty-three out of 288 procedures were identified as suspected device-infected interventions. Half of the patients had microbiologically confirmed infection after wound, blood or lumbar fluid culture. The odds ratio (OR) for explantation of the device was 19 for the presence of decubitus, a sign of medical device related pressure injury (P < 0.0005) and 5 for positive wound culture (P < 0.0452). Medical indication leading to device implantation and the antibiotics on discharge also played a role in the decision of device explantation. LIMITATIONS: Lack of external validity and others. CONCLUSION: In this study, presence of decubitus is the defining variable for device explantation when a infection is suspected rather than waiting to culture results. Due to a high variability in infection rates, multidisciplinary guidelines are needed to provide an approach that focuses on accurate data monitoring, rigurous implantation technique and standardized protocols. KEY WORDS: Chronic pain, spinal cord stimulation infection, neurostimulator, intrathecal drug delivery pump, complication, infection, explantation.