Preoperative hemoglobin A1c and perioperative blood glucose in patients with diabetes mellitus undergoing spinal cord stimulation surgery: A literature review of surgical site infection risk.

AIMS: The aim of our study was to review the surgical literature regarding the relationship between hemoglobin A1c (HbA1c), diagnosis of diabetes mellitus (DM), and risk of postoperative surgical site infection (SSI). METHODS: A librarian-assisted literature search was performed with two goals: (1) identify surgical publications related to SSI and HbA1c values, and (2) identify publications reporting infection risk with DM in spinal cord stimulation (SCS), intrathecal drug delivery systems (IDDS), and cardiovascular implantable electronic device (CIED) implantation surgeries. Published guidelines on perioperative management of DM are reviewed. RESULTS: We identified 30 studies reporting SSI and HbA1c values. The literature review indicated that for many surgical procedures, elevated HbA1c is not correlated to rate of SSI. We identified 16 studies reporting infection rates within DM cohorts following SCS, IDDS, and CIED implantation surgeries. The data reviewed did not indicate DM as an independent risk factor for SSI. CONCLUSION: Preoperative HbA1c levels in patients with a history of DM is not a singularly sufficient tool to estimate risk of perioperative infection in SCS implantation surgery. Published guidelines on perioperative management of DM do not suggest a specific HbA1c above which surgery should be delayed; intentional perioperative glycemic control is recommended.

The Prevalence of Elevated Impedances and Magnetic Resonance Imaging Ineligibility Following Implantation of 10 kHz Spinal Cord Stimulation Devices: A Retrospective Review.

OBJECTIVES: Spinal cord stimulation (SCS) is increasingly utilized in the treatment of multiple chronic pain conditions. However, patients will continue to experience other medical issues and the potential for future magnetic resonance imaging (MRI) needs must not be overlooked. SCS devices have device-specific MRI conditional labeling and if impedances are elevated the patient may not be able to obtain an MRI. With 10 kHz SCS devices specifically, an impedance value above 10,000 ohms (Ω) is MRI ineligible. The primary objective of this article was to report the incidence of elevated impedances with a multilumen lead design per electrode, per lead, and to describe the total number of MRI ineligible patients due to elevated impedances using 10 kHz SCS cutoff values. The secondary objective was to determine whether certain patient demographics or surgery characteristics put patients at increased risk of elevated impedances. MATERIALS AND METHODS: We performed a retrospective review of 327 patients who were implanted with a 10 kHz SCS device between January 2015 and November 2020. Regression models were fitted to determine associations between MRI ineligibility status with clinical characteristics including age, sex, BMI, lead location, implantable pulse generator (IPG) location, and time since implant. RESULTS: We found elevated impedances with subsequent MRI ineligibility in 13 patients (4.0%). Regression analysis did not identify any associations with MRI ineligibility and patient risk factors including age, sex, body mass index, lead location, IPG location, and follow-up time since implant. CONCLUSION: We found the prevalence of elevated impedances above 10,000 Ω to be 4% of implanted patients. This information is important for patients and physicians alike and should be considered when device selection is occurring in the pre-operative visits.

Systematic Literature Review of Spinal Cord Stimulation in Patients With Chronic Back Pain Without Prior Spine Surgery.

OBJECTIVE: Low back pain is the leading cause of disability worldwide and one of the most common reasons for seeking healthcare. Despite numerous care strategies, patients with low back pain continue to exhibit poor outcomes. Spinal cord stimulation (SCS) is an evidence-based therapeutic modality for patients with failed back surgery syndrome. For patients without a surgical lesion or history, minimally invasive interventions that provide long-term reduction of chronic back pain are needed. Therefore, we conducted a systematic review of the evidence on SCS therapy in patients with chronic back pain who have not undergone spinal surgery. MATERIALS AND METHODS: A systematic literature search was performed to identify studies reporting outcomes for SCS in chronic back pain patients (with or without secondary radicular leg pain) without prior surgery using date limits from database inception to February 2021. Study results were analyzed and described qualitatively. RESULTS: A total of ten primary studies (16 publications) were included. The included studies consistently demonstrated favorable outcomes in terms of pain reduction and functional improvement following SCS therapy. Improvements also occurred in quality of life scores; however, not all studies reported statistically significant findings. Additionally, the studies reported that SCS resulted in high patient satisfaction, reductions in opioid use, and an acceptable safety profile, although these data were more limited. CONCLUSION: Findings suggest that SCS is a promising, safe, minimally invasive, and reversible alternative option for managing chronic back pain in patients who have not undergone spinal surgery.

Antibacterial Envelope Use for the Prevention of Surgical Site Infection in Spinal Cord Stimulator Implantation Surgery: A Retrospective Review of 52 Cases.

OBJECTIVE: Surgical site infection in patients who undergo spinal cord stimulator implant surgery represents a significant concern in terms of increased health care costs and patient morbidity. The use of antibacterial envelopes in spinal cord stimulator implant surgeries has not been previously described. The aim of this retrospective review was to evaluate the effectiveness of the antibacterial envelope in reducing surgical site infection in spinal cord stimulator implant surgeries when used adjunctively to standard infection prevention measures. MATERIALS AND METHODS: The study included 52 patients, all of whom were implanted with a spinal cord stimulator between January 2015 and November 2020. To be included, patients were required to have had an antibacterial envelope utilized at the time of surgery. Patient records were retrospectively reviewed. All patients who received an antibacterial envelope at the time of implant surgery were included. RESULTS: Data was collected and analyzed on 52 permanent SCS implantations, including primary implantation (n=26) and revision surgery (n=26). All patients were at least three months post-operative from the implant surgery (average follow-up time period was 518.4 days). There were no surgical site infections reported in the 52 patient cohort. CONCLUSION: Antibiotic impregnated envelopes appear to be a safe and effective modality to decrease surgical site infection risk in spinal cord stimulation implant surgeries.

Paresthesia-Based Versus High-Frequency Spinal Cord Stimulation: A Retrospective, Real-World, Single-Center Comparison.

OBJECTIVE: Spinal cord stimulation (SCS) has become a common treatment modality for chronic pain of various etiologies. Over the past two decades, significant technological evolution has occurred in the SCS space, and this includes high-frequency (10 kHz) stimulation. Level I evidence exists reporting superiority of 10 kHz SCS over traditional SCS, however, conflicting reports have been published. The primary objective was to report site-collected real-world patient reported percentage improvement in pain scale (PR-PIPS) with traditional SCS and 10 kHz SCS from a single, academic medical center. MATERIALS AND METHODS: This study was a single-center retrospective review to determine PR-PIPS of traditional SCS and 10 kHz SCS in those patients implanted for at least 12 months. Data were collected by two independent physicians not involved with the implant surgery to minimize bias in the data collection process. PR-PIPS and other clinical variables were abstracted either via chart review or via phone call for patients who were at least 12 months post-implant at the last clinical follow-up. RESULTS: A total of 163 implanted patients (traditional stimulation n = 85; high-frequency stimulation n = 78) were identified. Twenty-two explants (traditional stimulation n = 10; high-frequency stimulation n = 12) were performed (13.5%). Seventy-five total remaining SCS implants utilizing traditional stimulation and 66 total remaining SCS implants utilizing high-frequency stimulation were included. There was no difference in PR-PIPS between traditional stimulation (50.6% ± 30.1%) and high-frequency stimulation (47.6% ± 31.5%) in the adjusted linear regression model in a variety of implant indications (p = 0.399). There was no difference in frequency of patient categorization into various thresholds of percentage pain relief based on type of stimulation. The most common reasons for explant were loss of efficacy (50.0%) and infection (40.0%) in the traditional cohort, and loss of efficacy (58.3%) in the high-frequency cohort. CONCLUSIONS: This study adds further evidence to the published literature that successful long-term results can be achieved with SCS. Our retrospective analysis did not find a statistically significant difference in PR-PIPS between traditional stimulation and high-frequency stimulation in a variety of indications over an average follow-up of nearly two years. Notably, there were statistically significant differences in treatment indications and primary sites of pain between the two patient cohorts, and this should be considered when interpreting the results.

Explantation of 10 kHz Spinal Cord Stimulation Devices: A Retrospective Review of 744 Patients Followed for at Least 12 Months.

OBJECTIVES: High-frequency 10 kHz spinal cord stimulation (10 kHz-SCS) has achieved analgesia superior to traditional SCS in a number of studies. However, there is concern regarding long-term outcomes of 10 kHz-SCS. Prior work has suggested that explant rates are higher with 10 kHz-SCS. Our primary objective was to determine the explant rate of 10 kHz-SCS in a large patient cohort from multiple centers followed for at least 12 months after implant surgery. MATERIALS AND METHODS: We performed a retrospective chart review of all patients who received a 10 kHz-SCS implant before July 1, 2019. We abstracted patient demographics, implant date, primary site of pain, implant indication, explant date, and reason for explant. A total of 744 patients were included in the study analysis. RESULTS: Average age of the overall cohort was 65.53 years and 407 (54.7%) were women. Average follow-up for all patients was 793 days. There were a total of 76 explants (10.2%). The most common reason for explant was loss of efficacy, which accounted for 39 explants (51.3% of total explants, 5.2% of overall cohort). Female sex and radiculopathy as the SCS indication were associated with statistically significant decreased risk of 10 kHz-SCS explant. CONCLUSIONS: We found 10 kHz-SCS explant rates to be similar to prior reported explant rates for traditional SCS devices. Patient-related factors including female sex and radiculopathy as the primary SCS indication may be protective factors against explantation.

Scrambler therapy for chemotherapy neuropathy: a randomized phase II pilot trial.

INTRODUCTION: Chemotherapy-induced peripheral neuropathy (CIPN) is a prominent clinical problem, with limited effective therapies. Preliminary non-randomized clinical trial data support that Scrambler Therapy is helpful in this situation. METHODS: Patients were eligible if they had CIPN symptoms for at least 3 months and CIPN-related tingling or pain at least 4/10 in severity during the week prior to registration. They were randomized to receive Scrambler Therapy versus transcutaneous electrical nerve stimulation (TENS) for 2 weeks. Patient-reported outcomes (PROs) were utilized to measure efficacy and toxicity daily for 2 weeks during therapy and then weekly for 8 additional weeks. RESULTS: This study accrued 50 patients, 25 to each of the 2 study arms; 46 patients were evaluable. There were twice as many Scrambler-treated patients who had at least a 50% documented improvement during the 2 treatment weeks, from their baseline pain, tingling, and numbness scores, when compared with the TENS-treated patients (from 36 to 56% compared with 16-28% for each symptom). Global Impression of Change scores for "neuropathy symptoms," pain, and quality of life were similarly improved during the treatment weeks. Patients in the Scrambler group were more likely than those in the TENS group to recommend their treatment to other patients, during both the 2-week treatment period and the 8-week follow-up period (p < 0.0001). Minimal toxicity was observed. CONCLUSIONS: The results from this pilot trial were positive, supporting the conduct of further investigations regarding the use of Scrambler Therapy for treating CIPN.

Spinal Stimulation for the Treatment of Intractable Spine and Limb Pain: A Systematic Review of RCTs and Meta-Analysis.

OBJECTIVE: To synthesize the evidence regarding the effect of spinal stimulation (SS) vs medical therapy (MT) and the effect of newer SS technologies vs conventional SS on pain reduction in patients with intractable spine or limb pain. METHODS: A comprehensive literature search was conducted by a reference librarian. The literature search encompassed January 1, 1995 - December 31, 2017. Reviewers worked independently to select and appraise trials. Random-effect meta-analysis and frequentist indirect comparison methods were used to compare the three interventions. Results were expressed as odds ratio (OR) or weighted mean difference (WMD) with 95% CIs. RESULTS: We identified 12 trials enrolling 980 patients. Compared with MT, SS significantly increased the odds of reducing pain by 50% or more in three trials (OR, 13.01; 95% CI, 4.96-34.17) and significantly reduced pain as measured by visual analogue scale scores in three trials (WMD, 1.43 scale points; 95% CI, 0.16-2.71). Using the common comparator of MT, newer stimulation technology (eg, high-frequency 10 kilohertz spinal stimulation, Burst, dorsal root ganglion) was associated with increased odds of pain relief compared with conventional SS (OR, 2.07; 95% CI, 1.35-3.19). CONCLUSIONS: In patients with intractable spine/limb pain, SS was associated with better pain reduction than MT. New stimulation technology was likely associated with better pain reduction than conventional stimulation.

Curing Opioid Toxicity with Intrathecal Targeted Drug Delivery.

Pain is one of the most feared symptoms that concern cancer patients and their families. Despite well-established guidelines set forth by the World Health Organization (WHO) on the treatment of cancer pain, nearly half of cancer patients report poorly controlled pain. One of the most serious side effects of systemic oral opioid use is neurotoxicity, which is characterized by altered mental status and systemic neurologic impairments. Treatment strategies are supportive in nature and focused on reducing or changing the offending opioid and correcting any metabolic deficiencies. Herein, we discuss a case of opioid-induced neurotoxicity treated with intrathecal targeted drug delivery (TDD). The timing and implementation of advanced therapies such as intrathecal TDD is not well delineated. More importantly, patients and their oncologic providers are often unaware of this useful tool in treating challenging cancer-associated pain and significantly minimizing systemic opioid side effects. To ensure that patients have comprehensive oncologic care, best-practice guidelines suggest involvement of an interdisciplinary team and coordinated care. Early referral to a pain and palliative specialist may allow for improved patient outcomes and removal of unnecessary barriers to optimal patient care.

Refractory Pain Management in Amyloid-Associated Peripheral Neuropathy.

OBJECTIVE: Systemic amyloidosis is a disease that often involves multiple organ systems, including the peripheral nervous system. Patients may present with severe, refractory neuropathic pain; however, the optimal treatment approach for pain for these patients remains unclear. CASE REPORT: A man with severe, refractory neuropathic pain in his bilateral upper and lower extremities and the trunk secondary to amyloid neuropathy is presented. Multiple medication trials, including neuropathic and opioid agents, produced considerable adverse effects and minimal relief. Scrambler therapy, a novel electrical stimulation modality, was used and was associated with substantial short-term but nonsustained benefit. Spinal cord stimulation was considered, but given his diffuse symptoms, it was deemed a less-than-optimal approach. Ultimately, an intrathecal drug delivery system was placed with infusion of hydromorphone, resulting in substantial pain reduction in all involved areas and with an improved adverse effect profile. This intervention resulted in immense improvement in the patient's quality of life, despite progression of his systemic amyloidosis. CONCLUSIONS: Severe pain in the setting of amyloid neuropathy is often difficult to treat. To our knowledge, this represents the first report of Scrambler therapy or an implanted intrathecal drug delivery system used for a patient with refractory amyloidosis-related neuropathic pain, resulting in substantial analgesic benefit and improved quality of life.

Utilization of Leads After Permanent Implant in Spinal Cord Stimulator Systems.

OBJECTIVE: The goal of this study was to determine the frequency and clinical indications associated with implantation of single vs. dual percutaneous lead spinal cord stimulator (SCS) systems and to look further into how these leads are utilized for treatment. MATERIALS AND METHODS: A retrospective cohort analysis of all patients undergoing SCS implantation between January 2001 and December 2013 with a minimum of 2 years of clinical follow-up was performed. Number of trial leads and implanted leads was recorded. For patients with dual-lead systems, it was noted if and when the second lead was used, along with the clinical indication for lead activation. RESULTS: In the 259-patient cohort, 15.8% (n = 41) patients underwent placement of a single-lead system, 83.0% (n = 215) underwent placement of a dual-lead system, and 1.2% (n = 3) underwent placement of 3-lead systems. Placement of dual-lead systems was similar among all indication groups. Of those patients with a dual-lead system in place, 88.1% utilized both leads and average time to programming of the second lead was 2.3 months. The most common reason to activate the second lead was inadequate stimulation coverage. Five of the 41 patients with single-lead systems underwent an additional surgery to implant a second lead due to inadequate stimulation with 1 lead. CONCLUSIONS: To our knowledge this is the first descriptive analysis of the frequency of single- and dual-lead SCS systems. This report indicates that dual-lead systems are most often placed and both leads are required for optimal patient therapy.

Bleeding Complications in Patients Undergoing Intrathecal Drug Delivery System Implantation.

INTRODUCTION: Intrathecal drug delivery systems (IDDSs) have dramatically improved analgesia and the functional status of cancer patients and those with chronic pain states. However, given the close proximity to the neuraxis and frequent concomitant use of antiplatelet or anticoagulant medications, this intervention is not without risk. The goal of this investigation was to determine the incidence of bleeding complications following IDDS placement. METHODS: This is a retrospective review from 2005 through 2014 of adult patients undergoing IDDS implantation or revision at a tertiary care center. The primary outcome was a bleeding-related neurological complication requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. RESULTS: A total of 247 procedures were performed on 216 unique patients. Patients received aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) within seven days of needle placement for 64 procedures (25.9%). A preprocedural platelet count or international normalized ratio (INR) was available within 30 days for 138 procedures (55.9%). Of these, two patients had a platelet count lower than 100 x 109/L and one patient had an INR of 1.5 or higher at the time of the procedure. One neurological complication was identified (0.4%) that was not related to procedural bleeding. Similarly, three patients (1.2%) received a periprocedural red blood cell transfusion, none of which were related to procedural bleeding. CONCLUSION: No cases of bleeding-related neurological complications were identified following IDDS placement or revision, including in those receiving aspirin or NSAIDs. Future investigations with larger numbers are needed to further explore the safety of antithrombotic therapy continuation or discontinuation periprocedurally.

Surgical Site Infections in Cancer Patients with Intrathecal Drug Delivery Devices.

Objectives: Our purpose was to determine the incidence of surgical site infection (SSI) in cancer patients receiving an intrathecal drug delivery system (IDDS) and compare that rate with the incidence of SSI in the general population receiving an IDDS or spinal cord stimulator. We attempted to describe risk factors for SSIs in cancer patients treated with IDDS in terms of exposure to cancer treatments. Design: Retrospective review. Setting: Large tertiary care center. Patients: Cancer patients receiving an IDDS in 2006-2013. Methods: The incidence of SSI was determined according to the US Centers for Disease Control and Prevention definition. Medication regimens and current cancer treatment were investigated to identify immunocompromised patients during IDDS placement. Microbacteriology, treatment, and overall outcomes were investigated. Results: Sixty-four patients had an IDDS implanted in 2006-2013. SSI developed in four patients (6.2%). All four patients had received chemotherapy or radiotherapy within three months before implantation. Three of the three were receiving dexamethasone, and three of the four required explantation of the IDDS. Conclusion: The incidence of SSI was at the upper end of the published infection rates for IDDS. The risk of SSI may be increased in this population because of factors that alter the patient's immune status, including concomitant corticosteroid use, radiotherapy near the SSI, and presence of immunomodulators. The identification and mitigation of certain risk factors for this population may prevent infection in future patients.