The effect of COVID-19 on pain control in patients with a neurostimulator in situ- a retrospective study.

BACKGROUND: De-novo chronic neuropathic pain following COVID-19 is widely recognised. However, there are currently no published studies investigating the effect of SARS-CoV-2 infection on patients with pre-existing neuropathic pain who have required spinal cord stimulator (SCS) implantation. Here, the authors aimed to analyse outcomes in their institution's patients who had spinal cord stimulator (SCS) implantation or revision procedures to the system over a 5-year period. Specifically, the short-term and long-term outcomes of patients who contracted COVID-19 during the follow-up period were compared to the control group of patients who did not. METHOD: Patients included in this study had spinal cord stimulator implantation (de-novo and revision procedures) between 1 January 2017 and 31 January 2022, for neuropathic pain of any aetiology. Patients deemed eligible for the study were invited to participate in a telephone survey through which clinical outcome data were collected. Pain scores were assessed with a modified form of the Brief Pain Inventory (BPI). RESULTS: Of 91 patients, 48 (52.7%) had contracted COVID-19 by the time of the survey. Patients who contracted COVID-19 had significantly worse BPI scores in the 'Least pain' domain following their infection and at time of the survey, when compared to their score 6 months after the operation. 22.9% (n = 11) of the patients who contracted COVID-19 experienced a change in their symptoms following their infection. Within this sub-group, there was a statistically significant deterioration in BPI scores in 10/11 domains following their infection and in 2/11 domains at time of the survey. Worsening severity of COVID-19 symptoms was not associated with worse BPI scores. CONCLUSIONS: Infection with SARS-CoV-2, in a significant proportion of patients with an SCS in situ, causes at least a transient deterioration in pain control. Further prospective multicentre studies are indicated to establish the prevalence of this phenomenon.

Spinal Cord Stimulation Trial Electrodes Rapidly Produce Epidural Scarring, Impeding Surgical Paddle Lead Placement.

OBJECTIVES: After a successful percutaneous cylindrical electrode five-to-seven-day trial of spinal cord stimulation, subsequent permanent surgical paddle lead (SPL) placement can be impeded by epidural scar induced by the trial leads (TLs). Our goal was to determine whether a delay between TL and subsequent SPL placement provokes enhanced epidural scarring with an increased need for laminotomy extension required for scar removal for optimal SPL placement. MATERIALS AND METHODS: Using a prospectively maintained data base, a single-facility/surgeon retrospective study identified 261 patients with newly placed thoracolumbar SPLs from June 2013 to November 2023. Data were obtained from the patients' charts, including, but not limited to, timing between TL and SPL, operative time, and need for extension of laminotomy. RESULTS: We found that the need for laminotomy extension due to TL epidural scarring and longer operative times was not required in our patients if the SPL was placed within ten days of placement of the TL (0/26), leading to shorter operative times in those with SPL placed after ten days (122.42 ± 10.72 minutes vs 140.75 ± 4.72 minutes; p = 0.005). We found no association with other medical comorbidities that may be confounding factors leading to epidural scarring/extension of laminotomy or association with level of SPL placement, size of the spinal canal, or indication for SPL placement. CONCLUSIONS: TL placement leads to scarring in the epidural space that appears to mature after ten days of its placement. In approximately 34% of patients, this leads to prolonged operative time owing to the need for extension of laminotomy and subsequent clearing of epidural scar for optimal SPL placement.

Discrepancy Between Reported and Calculated Pain Reduction in Patients With Spinal Cord Stimulation Therapy and Lack of Agreement Between Patient Satisfaction and Degree of Pain Relief.

OBJECTIVES: This study aimed to determine agreement between reported percentage pain reduction (RPPR) and calculated percentage pain reduction (CPPR) in patients with percutaneous spinal cord stimulation (SCS) implants, and to correlate RPPR and CPPR with patient satisfaction. We also sought to determine which patient-reported outcome measures are most improved in patients with SCS. MATERIALS AND METHODS: Fifty patients with percutaneous spinal cord stimulator implants with a mean follow-up of 51.1 months were interviewed and surveyed to assess their pain level, impression of degree of pain relief, satisfaction with the therapy, and desire to have the device again. Baseline pain level was obtained from their preimplant records. RESULTS: Overall, RPPR was found to be 53.3%, whereas CPPR was 44.4%. Of all patients, 21 reported <50% pain reduction; however, most of these (12/21, 57%) were satisfied with the outcome of therapy. In terms of individual improvement in outcomes, activities of daily life was the most improved measure at 82%, followed by mood, sleep, medication use, and health care utilization at 74%, 62%, 50%, and 48%, respectively. CONCLUSIONS: RPPR appears to be a complex outcome measure that may not agree with CPPR. Overall RPPR is greater than the CPPR. On the basis of our data, these independently valid measures should not be used interchangeably. A 50% pain reduction threshold is not a requisite for patient satisfaction and desire to have the device again. Activities of daily living was the most improved measure in this cohort, followed by mood, sleep, medication usage, and decrease in health care utilization.

Neuromodulation and Habituation: A Literature Review and Conceptional Analysis of Sustaining Therapeutic Efficacy and Mitigating Habituation.

Spinal cord stimulation (SCS) is a therapeutic modality for the treatment of various chronic pain conditions that has rapidly evolved over the past 50 years. Unfortunately, over time, patients implanted with SCS undergo a habituation phenomenon leading to decreased pain relief. Consequently, the discovery of new stimulation waveforms and SCS applications has been shown to prolong efficacy and reduce explantation rates. This article explores various SCS waveforms, their applications, and proposes a graded approach to habituation mitigation. We suspect the neural habituation phenomenon parallels that seen in pharmacology. Consequently, we urge further exploration of the early introduction of these stimulation strategies to abate spinal cord stimulation habituation.

Management of Refractory Cancer Pain with Intrathecal Drug Delivery and Spinal Cord Stimulation.

Background: Intrathecal pumps (ITPs) are indicated for refractory cancer pain and decrease systemic opioid requirements. While not yet indicated for cancer pain, spinal cord stimulators (SCSs) are used off-label for cancer pain, with increasing evidence of their efficacy. Materials and Methods: A retrospective chart review was conducted of patients who underwent both ITP and at least SCS trial for cancer pain. Primary outcomes were pain numeric rating scale (NRS) and daily morphine equivalents (MEQs). Results: Seventeen patients were identified. Both ITP and SCS were associated with significant decreases in pain ratings at the 3-month follow-up, but this decrease became nonsignificant subsequently. ITP, but not SCS, was associated with a significant decrease in MEQ. Conclusions: ITP and SCS may both provide efficacy for cancer pain, but the opioid-sparing effects of SCS may be limited. ITP and SCS may potentially be complementary in their ability to provide relief from cancer-related pain.

Development and Evaluation of a Virtual Reality Simulator for Spinal Cord Stimulation: A Randomized Controlled Trial.

Purpose: The aim of this prospective study was to develop a virtual reality simulator (VRS) for spinal cord stimulation (SCS) trials and establish its effectiveness. Methods: We developed a VRS for SCS training by integrating patient imaging data analytics, creating artificial X-ray images, and using spatial alignment techniques and virtual reality technologies. The simulator was created by a physician with considerable experience in performing SCS, and can simulate the feeling of the procedure in a virtual environment. The efficacy of the simulator for SCS trials was assessed using a cohort of 20 novice trainees. The primary outcomes were duration of the procedure, checklist score, number of C-arm images captured, and overall trainee satisfaction. Results: The cohort that utilized the VRS had better Zwisch scale scores (P <0.001), completed the procedure in a shorter time (P <0.001), took fewer C-arm images (P <0.001), and reported better overall satisfaction (P = 0.011) than the cohort that did not. Conclusion: We developed a realistic and efficient VRS for educating novice trainees on SCS trials, thereby eliminating the risk of radiation exposure associated with cadaver training. The results of this study indicate that our VRS has potential as an instrumental resource that can be integrated into the educational framework for SCS trials.

Factors Associated With Same Day Discharge Post-Spinal Cord Stimulator Placement.

BACKGROUND: Spinal cord stimulator (SCS) surgeries, whether performed using the open or percutaneous approach, are becoming increasingly common for a range of neuropathic pain conditions, including post-laminectomy syndrome and complex regional pain syndrome. However, there is limited knowledge regarding the factors linked to same-day discharge patterns following SCS. OBJECTIVE: The purpose of this study was to identify factors associated with same-day discharge after SCS placement. The primary outcome was same-day discharge. STUDY DESIGN: Retrospective, cohort study using a nationwide database. METHODS: Inclusion criteria included patients who underwent percutaneous or open SCS from January 1, 2014 through December 31, 2021. Exclusion criteria included patients with missing data (n = 178) and those with SCS implants for unlisted indications (n = 1,817). A multivariable analysis was conducted on the outcome data and co-variates associated with same-day discharge after SCS. RESULTS: After applying inclusion and exclusion criteria, a total of 18,058 patients remained in the final data set, including 7,339 patients who underwent percutaneous SCS and 10,719 patients who underwent open SCS procedures. After analysis, factors associated with increased rates of same-day discharge after SCS included men (odds ratio [OR] 1.16; 95% CI, 1.09 -1.24;  P < 0.001), patients on Medicaid (OR 1.64; 95% CI, 0.1.34 - 2.01; P < 0.001), and hospitals in the US Midwest (OR 1.66; 95% CI, 1.45 - 1.90; P < 0.001) and hospitals in the US West (OR 1.32; 95% CI, 1.20 - 1.46; P < 0.001). Factors associated with decreased rates of same-day discharge after SCS included the open approach (OR 0.21; 95% CI, 0.19 - 0.23; P < 0.001), Hispanic ethnicity (OR 0.61; 95% CI, 0.54 - 0.69; P < 0.001) and increased age (OR 0.99; 95% CI, 0.98 - 0.99; P < 0.001). LIMITATIONS: Since our study is retrospective, the data are subject to various biases, including variable confounding, human error in data entry, and generalizability of the results. CONCLUSION: These results can be used to help determine hospital bed needs post-SCS surgery. Future research should focus on identifying the specific reasons certain demographic and geographic factors might influence same-day discharge rates. Our study provides important insights into the factors associated with same-day discharge rates post open and percutaneous SCS implant and highlights the need for patient-centered, evidence-based approaches to health care delivery.

Epidural spread of surgical site infection from spinal cord stimulation trial.

We present a case of deep surgical site infection (SSI) at a spinal cord stimulator (SCS) trial implantation site, resulting from an allergic reaction to an unknown agent. A 38-year-old female with complex regional pain syndrome began an SCS trial, noting 100% pain relief for 5 days. Fluid drainage from the surgical site was reported on POD6 and trial leads were removed the following day. The patient was hospitalized with sepsis. Blood cultures revealed Staphylococcus aureus. MRIs showed skin breakdown and cellulitis of the paraspinal musculature extending into the epidural space. The patient was maintained with antibiotics and rigorous wound care for 9 days and the surgical site infection resolved. The patient proceeded to SCS implantation, and reported good pain relief with the implanted device.

This case report describes the treatment of an infection developed during a spinal cord stimulator (SCS) trial period. SCS are medical devices used to treat pain, they work by applying electrical current to the areas of the spinal cord that cause patients' pain. Before patients get an SCS device implanted, they often undergo a trial period first. During a trial, the stimulator device stays outside the body, and only the wires carrying electricity to the spinal cord are implanted. Typically, SCS trial and implantation procedures are safe and result in effective pain relief. However, infections are a dangerous potential complication that can result from these procedures. In our case, the patient developed an infection during an SCS trial period, likely resulting from an allergic reaction to their surgical dressings. The infection traveled down the wires and nearly reached the spinal cord. Since the infection was quickly identified and managed, devastating complications were avoided. The patient was able to get a permanent SCS after the infection was resolved, and had effective pain relief. Our report emphasizes the importance of using strict infection prevention techniques, and monitoring patients for signs of infection throughout SCS trials.