The analgesic effectiveness of perioperative lidocaine infusions for acute and chronic persistent postsurgical pain in patients undergoing breast cancer surgery: a systematic review and meta-analysis.

BACKGROUND: Breast cancer is the most common cancer among women and tumour resection carries a high prevalence of chronic persistent postsurgical pain (CPSP). Perioperative i.v. lidocaine infusion has been proposed as protective against CPSP; however, evidence of its benefits is conflicting. This review evaluates the effectiveness of perioperative lidocaine infusions for breast cancer surgery. METHODS: Randomised trials comparing perioperative lidocaine infusions with parenteral analgesia in breast cancer surgery patients were sought. The two co-primary outcomes were the odds of CPSP at 3 and 6 months after operation. Secondary outcomes included rest pain at 1, 6, 12, and 24 h; analgesic consumption at 0-24 and 25-48 h; quality of recovery; opioid-related side-effects; and lidocaine infusion side-effects. Hartung-Knapp-Sidik-Jonkman (HKSJ) random effects modelling was used. RESULTS: Thirteen trials (1039 patients; lidocaine: 518, control: 521) were included. Compared with control, perioperative lidocaine infusion did not decrease the odds of developing CPSP at 3 and 6 months. Lidocaine infusion improved postoperative pain at 1 h by a mean difference (95% confidence interval) of -0.65 cm (-0.73 to -0.57 cm) (P<0.0001); however, this difference was not clinically important (1.1 cm threshold). Similarly, lidocaine infusion reduced oral morphine consumption by 7.06 mg (-13.19 to -0.93) (P=0.029) over the first 24 h only; however, this difference was not clinically important (30 mg threshold). The groups were not different for any of the remaining outcomes. CONCLUSIONS: Our results provide moderate-quality evidence that perioperative lidocaine infusion does not reduce CPSP in patients undergoing breast cancer surgery. Routine use of lidocaine infusions for perioperative analgesia and CPSP prevention is not supported in this population. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42023420888.

Systematic Reviews and Meta-analyses in Regional Anesthesia and Pain Medicine (Part I): Guidelines for Preparing the Review Protocol.

Comprehensive resources exist on how to plan a systematic review and meta-analysis. The objective of this article is to provide guidance to authors preparing their systematic review protocol in the fields of regional anesthesia and pain medicine. The focus is on systematic reviews of health care interventions, with or without an aggregate data meta-analysis. We describe and discuss elements of the systematic review methodology that review authors should prespecify, plan, and document in their protocol before commencing the review. Importantly, authors should explain their rationale for planning their systematic review and describe the PICO framework-participants (P), interventions (I), comparators (C), outcomes (O)-and related elements central to constructing their clinical question, framing an informative review title, determining the scope of the review, designing the search strategy, specifying the eligibility criteria, and identifying potential sources of heterogeneity. We highlight the importance of authors defining and prioritizing the primary outcome, defining eligibility criteria for selecting studies, and documenting sources of information and search strategies. The review protocol should also document methods used to evaluate risk of bias, quality (certainty) of the evidence, and heterogeneity of results. Furthermore, the authors should describe their plans for managing key data elements, the statistical construct used to estimate the intervention effect, methods of evidence synthesis and meta-analysis, and conditions when meta-analysis may not be possible, including the provision of practical solutions. Authors should provide enough detail in their protocol so that the readers could conduct the study themselves.

Systematic Reviews and Meta-analyses in Regional Anesthesia and Pain Medicine (Part II): Guidelines for Performing the Systematic Review.

In Part I of this series, we provide guidance for preparing a systematic review protocol. In this article, we highlight important steps and supplement with exemplars on conducting and reporting the results of a systematic review. We suggest how authors can manage protocol violations, multiplicity of outcomes and analyses, and heterogeneity. The quality (certainty) of the evidence and strength of recommendations should follow the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. It is our goal that Part II of this series provides valid guidance to authors and peer reviewers who conduct systematic reviews to adhere to important constructs of transparency, structure, reproducibility, and accountability. This will likely result in more rigorous systematic reviews being submitted for publication to the journals like Regional Anesthesia & Pain Medicine and Anesthesia & Analgesia .

Treatment Disparities in Hispanic Patients with Chronic Pain: An Evidence-Based Narrative Review.

PURPOSE OF REVIEW: The purpose of this narrative review is to summarize healthcare disparities experienced by Hispanic and Latino/Latinx patients with chronic pain, evaluate the existing literature exploring the specific therapeutic inequities affecting this patient population, and identify gaps in the literature requiring future study. RECENT FINDINGS: Hispanic and Latino/Latinx patients experience disparities in chronic pain management. They are less likely to be prescribed pharmacologic therapies, including non-steroidal anti-inflammatory drugs and opioids. Hispanic and Latino/Latinx patients are also less likely to receive spinal cord stimulators and may be charged higher costs for them. There are no published studies specifically assessing Hispanic and Latino/Latinx patients' utilization and outcomes from other common interventional pain procedures (e.g., epidural steroid injections, radiofrequency ablation). Limited data suggest non-pharmacologic treatments, such as cognitive behavioral therapy and complementary/integrative health modalities, might have more benefit for this population, potentially because of greater utilization. Hispanic and Latino/Latinx patients experience disparities in chronic pain management. There is a paucity of data available pertaining specifically to pain-related outcomes and the utilization of pain treatment modalities, especially in regard to interventional procedures. Additional research is urgently needed in order to understand the full extent of these disparities and develop solutions to provide more equitable care.

A comprehensive review of the typical and atypical side effects of gabapentin.

BACKGROUND: Gabapentin, a widely prescribed medication for various neuropathic pain conditions, has demonstrated efficacy in managing diverse neurological disorders. While conventional side effects are well-documented, a growing body of evidence suggests the existence of atypical side effects, necessitating comprehensive exploration. This paper aims to systematically review and summarize the literature on the atypical side effects of gabapentin, shedding light on manifestations beyond the conventional spectrum. METHODS: A systematic review was conducted, encompassing peer-reviewed articles published up to the knowledge cutoff date in November 2023. Databases, specifically PubMed, were searched for relevant studies, focusing on atypical side effects such as myoclonus, ataxia, pediatric aggression, respiratory depression, pneumonia, pregnancy complications, sleep interference, encephalopathy, peripheral edema, suicidal ideation, dyskinesia, anorgasmia, and myopathy. Inclusion criteria comprised studies with a focus on gabapentin-related atypical side effects, published in recognized journals and involving human subjects. RESULTS: The review identified a spectrum of atypical side effects associated with gabapentin use, ranging from neurological manifestations like myoclonus and ataxia to behavioral changes such as pediatric aggression and suicidal ideation. Additionally, respiratory complications, pregnancy-related issues, sleep disturbances, and rare complications like encephalopathy and myopathy were observed. Literature synthesis provided insights into the incidence, clinical presentation, and potential mechanisms underlying these atypical side effects. CONCLUSION: This comprehensive review highlights the diverse range of atypical side effects associated with gabapentin use, expanding beyond conventional knowledge. Healthcare practitioners must be cognizant of these manifestations, recognizing their potential impact on patient well-being. As clinical decision-making relies on a thorough understanding of a medication's side effect profile, this review contributes to enhancing awareness and fostering informed practices in the prescription and management of gabapentin. Further research is warranted to elucidate the mechanisms and risk factors associated with these atypical side effects, refining our understanding of gabapentin's safety profile.

Incidence of subsequent surgical decompression following minimally invasive approaches to treat lumbar spinal stenosis: A retrospective review.

BACKGROUND CONTEXT: Surgical decompression is the definitive treatment for managing symptomatic lumbar spinal stenosis; however, select patients are poor surgical candidates. Consequently, minimally invasive procedures have gained popularity, but there exists the potential for failure of therapy necessitating eventual surgical decompression. PURPOSE: To evaluate the incidence and characteristics of patients who require surgical decompression following minimally invasive procedures to treat lumbar spinal stenosis. STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: Patients who underwent minimally invasive procedures for lumbar spinal stenosis (Percutaneous Image-guided Lumbar Decompression [PILD] or interspinous spacer device [ISD]) and progressed to subsequent surgical decompression within 5 years. OUTCOME MEASURES: The primary outcome was the rate of surgical decompression within 5 years following the minimally invasive approach. Secondary outcomes included demographic and comorbid factors associated with increased odds of requiring subsequent surgery. METHODS: Patient data were collected using the PearlDiver-Mariner database. The rate of subsequent decompression was described as a percentage while univariable and multivariable regression analysis was used for the analysis of predictors. RESULTS: A total of 5278 patients were included, of which 3222 (61.04%) underwent PILD, 1959 (37.12%) underwent ISD placement, and 97 (1.84%) had claims for both procedures. Overall, the incidence of subsequent surgical decompression within 5 years was 6.56% (346 of 5278 patients). Variables associated with a significantly greater odds ratio (OR) [95% confidence interval (CI)] of requiring subsequent surgical decompression included male gender and a prior history of surgical decompression by 1.42 ([1.14, 1.77], p = 0.002) and 2.10 times ([1.39, 3.17], p < 0.001), respectively. In contrast, age 65 years and above, a diagnosis of obesity, and a Charlson Comorbidity Index score of three or greater were associated with a significantly reduced OR [95% CI] by 0.64 ([0.50, 0.81], p < 0.001), 0.62 ([0.48, 0.81], p < 0.001), and 0.71 times ([0.56, 0.91], p = 0.007), respectively. CONCLUSIONS: Minimally invasive procedures may provide an additional option to treat symptomatic lumbar spinal stenosis in patients who are poor surgical candidates or who do not desire open decompression; however, there still exists a subset of patients who will require subsequent surgical decompression. Factors such as gender and prior surgical decompression increase the likelihood of subsequent surgery, while older age, obesity, and a higher Charlson Comorbidity Index score reduce it. These findings aid in selecting suitable surgical candidates for better outcomes in the elderly population with lumbar spinal stenosis.

Relationship between number of prior lumbar spine surgeries and outcomes following spinal cord stimulator implantation: A multisite, retrospective pooled analysis.

OBJECTIVES: Lumbar spine surgery is a common procedure for treating disabling spine-related pain. In recent decades, both the number and cost of spine surgeries have increased despite technological advances and modification in surgical technique. For those patients that have continued uncontrolled back and/or lower extremity pain following lumbar spine surgery, spinal cord stimulation (SCS) has emerged as a viable treatment option. However, the impact of lumbar spine surgical history remains largely unstudied. Specifically, the current study considers the impact of number of prior lumbar spine surgeries on pain relief outcomes following SCS implantation. MATERIALS AND METHODS: We queried the electronic medical record of five separate pain practices for all patients who have undergone a SCS implant between January 1, 2017, and March 1, 2020. Inclusion criteria consisted of any patients with an SCS implant who underwent a prior lumbar spine surgery. The primary outcome was the mean calculated percentage pain relief in patients based on number of prior lumbar spine surgeries. RESULTS: There was a total of 1974 total SCS implant cases identified across five separate pain clinics. There was no difference in mean calculated pain relief in patients with one prior spine surgery versus those with two or more prior spine surgeries (28.2% vs. 25.8%, adjusted ß-coefficient -3.1, 95% CI -8.9 to 2.7, p = 0.290). Similarly, when analyzing number of spine surgeries as a continuous variable, there was no association between number of spine surgeries and calculated pain relief (adjusted ß-coefficient -1.5, 95% CI -4.0 to 1.1, p = 0.257). Additionally, after patients were stratified based on waveform, there was no association between number of prior lumbar spine surgeries (analyzed both as a categorical and continuous variable) and calculated percentage pain relief. CONCLUSIONS: This multicentered retrospective study found that there was no significant difference in pain scores in individuals who received SCS following one or more lumbar spine surgeries. Additionally, the waveform of the SCS device had no statistically significant impact on post-operative pain scores following one or more lumbar spine surgeries.

Analgesic Effectiveness of Motor-sparing Nerve Blocks for Total Knee Arthroplasty: A Network Meta-analysis.

BACKGROUND: The analgesic effectiveness of contemporary motor-sparing nerve blocks used in combination for analgesia in total knee arthroplasty is unclear. This network meta-analysis was conducted to evaluate the analgesic effectiveness of adding single-injection or continuous adductor canal block (ACB) with or without infiltration of the interspace between the popliteal artery and the capsule of the posterior knee (iPACK) to intraoperative local infiltration analgesia (LIA), compared to LIA alone, after total knee arthroplasty. METHODS: Randomized trials examining the addition of single-injection or continuous ACB with or without single-injection block at the iPACK to LIA for total knee arthroplasty were considered. The two primary outcomes were area-under-the-curve pain scores over 24 to 48 h and postoperative function at greater than 24 h. Secondary outcomes included rest pain scores at 0, 6, 12, and 24 h; opioid consumption (from 0 to 24 h and from 25 to 48 h); and incidence of nausea/vomiting. Network meta-analysis was conducted using a frequentist approach. RESULTS: A total of 27 studies (2,317 patients) investigating the addition of (1) single-injection ACB, (2) continuous ACB, (3) single-injection ACB and single-injection block at the iPACK, and (4) continuous ACB and single-injection block at the iPACK to LIA, as compared to LIA alone, were included. For area-under-the-curve 24- to 48-h pain, the addition of continuous ACB with single-injection block at the iPACK displayed the highest P-score probability (89%) of being most effective for pain control. The addition of continuous ACB without single-injection block at the iPACK displayed the highest P-score probability (87%) of being most effective for postoperative function. CONCLUSIONS: The results suggest that continuous ACB, but not single-injection ACB and/or single-injection block at the iPACK, provides statistically superior analgesia when added to LIA for total knee arthroplasty compared to LIA alone. However, the magnitude of these additional analgesic benefits is clinically questionable.

Treatment of Ulnar Neuropathic Pain with Peripheral Nerve Stimulation: Two Case Reports.

Ulnar neuropathy is a condition that manifests with symptoms of neuropathic pain, numbness, tingling, and even possible motor deficits in the ulnar distribution of the arm. This debilitating painful condition may be refractory to conservative, pharmacologic, and surgical interventions. Peripheral nerve stimulation (PNS) technology has advanced significantly in recent years allowing for conditions such as ulnar neuropathy to be treated in a minimally invasive manner. Here we report the first case reports in the literature (to our knowledge) of two patients with intractable ulnar neuropathy who underwent minimally invasive PNS Bioventus implants. Both patients experienced at least 75% pain relief based on NRS scores at 6 months after ulnar nerve PNS implantation. The patients also experienced significant improvement in functional outcomes, including return to employment, ability to perform activities of daily living without any impairment, and improved quality of life measures. While the results presented in our two case reports are promising, we only provide observational data over a 6 to 15-month period post-implantation. Future well-powered, large-scale, and long-term randomized controlled trials are warranted to determine efficacy and long-term pain and functional outcomes from PNS therapy for treatment of ulnar neuropathy.

Pro-Con Debate: Role of Methadone in Enhanced Recovery After Surgery Protocols-Superior Analgesic or Harmful Drug?

Enhanced recovery after surgery (ERAS) protocols are standardized and designed to provide superior analgesia, reduce opioid consumption, improve patient recovery, and reduce hospital length of stay. Yet, moderate-to-severe postsurgical pain continues to afflict over 40% of patients and remains a major priority for anesthesia research. Methadone administration in the perioperative setting may reduce postoperative pain scores and have opioid-sparing effects, which may be beneficial for enhanced recovery. Methadone possesses a multimodal profile consisting of µ-opioid agonism, N-methyl-d-aspartate (NMDA) receptor antagonism, and reuptake inhibition of serotonin and norepinephrine. Furthermore, it may attenuate the development of chronic postsurgical pain. However, caution is advised with perioperative use of methadone in specific high-risk patient populations and surgical settings. Methadone's wide pharmacokinetic variability, opioid-related adverse effects, and potential negative impact on cost-effectiveness may also limit its use in the perioperative setting. In this PRO-CON commentary article, the authors debate whether methadone should be incorporated in ERAS protocols to provide superior analgesia with no increased risks.

Safety of Scrambler Therapy: A Systematic Review of Complications and Adverse Effects.

OBJECTIVE: The objective was to qualitatively synthesize all reported cases of complications, adverse effects, side effects, or harms arising from the use of scrambler therapy (ST). METHODS AND DESIGN: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The PubMed, Embase, Scopus, Web of Science, United States National Library of Medicine clinical trials registry, and Cochrane Central Register of Controlled Trials databases were searched from database inception to December 10, 2021. Case reports/series, abstracts, retrospective studies, and prospective studies (e.g., open-label trials, randomized controlled trials) pertaining to ST and any description of a complication, adverse effect, side effect, or harm were screened. The search protocol was developed a priori and registered via the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42021291838). RESULTS: A total of six RCTs, 19 prospective open-label trials, and 11 case series / case reports met the inclusion criteria, comprising 1,152 total patients. Two patients experienced contact dermatitis, and one patient reported minor ecchymosis that resolved without intervention. This yielded a composite complication rate of 0.26% (3/1,152). There were zero reported serious adverse events. CONCLUSIONS: When used in accordance with the treatment protocols described by the United States Food and Drug Administration and device manual, ST is associated with a reported composite complication rate that is orders of magnitude lower than those of invasive neuromodulation devices. ST neuromodulation is a safe alternative for patients who cannot undergo invasive neuromodulation device implantation because of either risk or preference.

Treatment of pain in length-dependent peripheral neuropathy with the use of spinal cord stimulation: a systematic review.

BACKGROUND: Chronic intractable pain from peripheral neuropathy is a debilitating condition that might not respond to conventional medical management and pharmacotherapy. The primary objective of this systematic review was to assess change (or reduction) in pain intensity in patients with length-dependent peripheral neuropathy after spinal cord stimulation (SCS) therapy. METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The primary outcome was change (or reduction) in pain intensity after 12 months of SCS therapy compared with baseline in participants with length-dependent peripheral neuropathy. Secondary outcomes included change in pain intensity after 6 months and change in opioid consumption after 12 months. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines were used to appraise the quality of evidence. RESULTS: Nineteen studies consisting of 376 participants who underwent SCS implantation met the inclusion criteria. Qualitative synthesis revealed that all eligible studies reported a significant improvement in pain intensity after 12 months of SCS therapy as compared with baseline. Mean differences with 95% confidence intervals were calculated for 4 studies, all of which achieved the minimal clinically important difference for change in pain intensity at 12 months. The GRADE quality of evidence for this outcome was appraised as very low quality. CONCLUSION: This systematic review highlights that SCS could lead to significant improvement in pain intensity for length-dependent peripheral neuropathy, although future well-powered randomized controlled trials are warranted to increase the certainty of evidence in this finding. STUDY REGISTRATION: PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) ID: CRD42022377572.

Peripheral Nerve Stimulation for Low Back Pain: A Systematic Review.

PURPOSE OF REVIEW: Low back pain (LBP) is a prevalent condition that is associated with diminished physical function, poor mental health outcomes, and reduced quality of life. Peripheral nerve stimulation (PNS) is an emerging modality that has been utilized to treat LBP. The primary objective of this systematic review is to appraise the level of evidence on the efficacy of PNS for treatment of LBP. RECENT FINDINGS: Twenty-nine articles were included in this systematic review, consisting of 828 total participants utilizing PNS as the primary modality for LBP and 173 participants using PNS as salvage or adjunctive therapy for LBP after SCS placement. Different modalities of PNS therapy were reported across studies, including conventional PNS systems stimulating the lumbar medial branch nerves, peripheral nerve field stimulation (PNFS), and restorative neuromuscular stimulation of the multifidus muscles. All studies consistently reported positive modest to moderate improvement in pain intensity with PNS therapy when comparing baseline pain intensity to each study's respective primary follow-up period. There was a very low GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) quality of evidence supporting this finding. Inconsistency was present in some comparative studies that demonstrated no difference between PNS therapy versus control cohorts (sham or SCS therapy alone), which therefore highlighted the potential for placebo effect. This systematic review highlights that PNS, PNFS, and neuromuscular stimulation may provide modest to moderate pain relief in patients with LBP, although evidence is currently limited due to risk of bias, clinical and methodological heterogeneity, and inconsistency in data.

Evidence-Based Treatment of Pain in Chemotherapy-Induced Peripheral Neuropathy.

PURPOSE OF REVIEW: Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and often painful condition that occurs after administration of chemotherapeutic agents. The primary objective of this systematic review was to appraise the literature on conservative, pharmacological, and interventional treatment options for CIPN pain. RECENT FINDINGS: There is level I evidence supporting modest to moderate improvement in CIPN pain from duloxetine treatment, as well as short-term modest improvement from physical therapy and acupuncture. Although opioid and cannabis administration may provide short-term modest improvement, administration is commonly limited by side effects. Generally, most studies reported no clinical benefit from yoga, topical neuropathic agents, gabapentinoids, and tricyclic antidepressants. Evidence is currently equivocal for scrambler therapy and transcutaneous electrical nerve stimulation. Finally, evidence on neuromodulation options is limited to mostly case reports/series and one observational study highlighting moderate improvement with auricular nerve stimulation. This systematic review provides an overview of conservative, pharmacologic, and interventional treatment modalities for CIPN pain. Furthermore, it provides a level of evidence and degree of recommendation based on the United States Preventive Services Task Force (USPSTF) criteria for each specific treatment modality.

Interventional Pain Physician Burnout During the COVID-19 Pandemic: A Survey from the American Society of Pain and Neuroscience.

PURPOSE OF REVIEW: The study sought to assess the prevalence of physician burnout among interventional pain physicians in 2022. RECENT FINDINGS: Physician burnout is major psychosocial and occupational health issue. Prior to the coronavirus disease of 2019 (COVID-19) pandemic, over 60% of physicians reported emotional exhaustion and burnout. Physician burnout was reported to become more prevalent in multiple medical specialties during the COVID-19 pandemic. An 18-question survey was distributed electronically to all ASPN members (n = 7809) in the summer of 2022 to assess demographics, burnout characteristics (e.g., Have you felt burned out due to COVID?), and strategies to cope with burnout and stress (e.g., reached out for mental health assistance). Members were able to complete the survey once and were unable to make changes to their responses once submitted. Descriptive statistics were used to assess the prevalence and severity of physician burnout within the ASPN community. Chi-square tests were used to examine differences in burnout by provider characteristics (age, gender, years practicing, and practice type) with p-values less than 0.05 indicating statistical significance. There were 7809 ASPN members that received the survey email, 164 of those members completed the survey, a response rate of 2.1%. The majority of respondents were male (74.1%, n = 120), 94% were attending physicians (n = 152), and 26% (n = 43) have been in practice for twenty years or longer. Most respondents expressed having experienced burnout during the COVID pandemic (73.5%, n = 119), 21.6% of the sample reported reduced hours and responsibilities during the pandemic, and 6.2% of surveyed physicians quit or retired due to burnout. Nearly half of responders reported negative impacts to their family and social lives as well as personal physical and mental health. A variety of negative (e.g., changes in diet, smoking/vaping) and positive coping strategies (e.g., exercise and training, spiritual enrichment) were employed in response to stress and burnout; 33.5% felt they should or had reached out for mental health assistance and suicidal ideations were expressed in 6.2% due to burnout. A high percentage of interventional pain physicians continue to experience mental symptoms that may lead to risk for significant issues going forward. Our findings should be interpreted with caution based on the low response rate. Evaluation of burnout should be incorporated into annual assessments given issues of survey fatigue and low survey response rates. Interventions and strategies to address burnout are warranted.

Does Fibromyalgia Affect the Outcomes of Spinal Cord Stimulation: An 11-Year, Multicenter, Retrospective Matched Cohort Study.

BACKGROUND: Fibromyalgia is a prevalent disorder manifesting with widespread musculoskeletal pain and central sensitization, as well as fatigue, sleep issues, psychologic distress, and poor quality of life. Patients with fibromyalgia also may be diagnosed with other painful conditions amenable to treatment with spinal cord stimulation (SCS), although it is unclear how these patients respond to SCS compared with patients without fibromyalgia. MATERIALS AND METHODS: We performed an 11-year, multicenter, retrospective matched cohort study comparing SCS-treated patients with fibromyalgia and those without fibromyalgia. The primary outcome was comparison in mean calculated percentage pain relief between cohorts at six months after SCS implantation. Secondary outcomes included comparison of patient satisfaction between six and 12 months after SCS implantation, and percentage of patients reporting opioid intake and neuropathic medication intake at six months and 12 months after SCS implantation. Adjusted regression analysis was performed to make comparisons while adjusting for age, sex, body mass index, Charlson comorbidity index, preoperative opioid intake, and preoperative neuropathic medication intake. RESULTS: Of 90 patients with fibromyalgia who underwent SCS trial, 18 patients (20%) failed their SCS trial and did not proceed toward implantation. Sixty-eight patients with fibromyalgia were matched to 141 patients in the control cohort based on age, sex, Charlson comorbidity index, and the American Society of Anesthesiologists physical status score. At six months after SCS implantation, there was no statistical difference in calculated percentage change in pain intensity between the fibromyalgia cohort (46.6 ± 29.0) and the control cohort (50.9 ± 32.8; ß, -18.4; 95% CI, -44.3 to 7.6; p = 0.157). At baseline, a greater percentage of patients in the fibromyalgia cohort reported preoperative opioid intake (51.5% vs 22.7%, p < 0.001) and preoperative neuropathic medication intake (67.6% vs 15.6%, p < 0.001). However, there was no difference between cohorts in the percentage of patients taking opioid or neuropathic medications at six months and 12 months after SCS implantation. Similarly, there was no difference between cohorts in the percentage of patients reporting satisfaction between six and 12 months. CONCLUSION: Patients with fibromyalgia who received a diagnosis approved for treatment with SCS may expect similar post-SCS-implantation pain relief, overall satisfaction, and analgesic use rate to those of patients without fibromyalgia.

Incidence of Neuraxial and Non-Neuraxial Hematoma Complications From Spinal Cord Stimulator Surgery: Systematic Review and Proportional Meta-Analysis.

OBJECTIVE: The goal of this meta-analysis was to estimate the incidence of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients who underwent temporary spinal cord stimulator (SCS) lead trial placement and permanent implantation of SCS leads and internal pulse generator (IPG). MATERIALS AND METHODS: A comprehensive search was conducted of databases of any publications before October 21, 2021. Eligible study designs included randomized control trials and prospective or retrospective observational studies with more than ten patients. The primary outcome variables were the incidences of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients with SCS. These dichotomous categorical outcomes were abstracted from studies after Freeman-Tukey arcsine square root transformation using random-effects meta-analysis (DerSimonian and Laird method). Pooled incidence rates and 95% CIs were calculated for each outcome variable. RESULTS: A total of 40 studies met the inclusion criteria. Included in the neuraxial and non-neuraxial hematoma analyses were 4751 patients and 3862 patients, respectively. The pooled incidence of any hematoma in patients with SCS was 0.81% (95% CI, 0.45%-1.27%). The pooled incidence of neuraxial hematoma in patients with SCS was 0.32% (95% CI, 0.18%-0.50%). This included primarily epidural hematomas (11/4751) but also comprised an intracranial hemorrhage in a patient on enoxaparin bridge therapy from warfarin and one patient not on anticoagulation with an intracranial subdural hematoma that resulted in death. The pooled incidence of non-neuraxial hematomas in patients with SCS was 0.59% (95% CI, 0.29%-1.00%). CONCLUSION: The overall incidence of hematomas in patients with temporary SCS trial lead placement and permanent SCS/IPG implantations is less than 1%. Furthermore, the incidence of neuraxial hematomas is less than 0.5%, which is of particular interest given the potential devastating consequences of this complication. The results of this study can be used to inform patients and implanting physicians on hematoma complications from SCS and highlight that the benefits of SCS outweigh the hematoma risks if anticoagulation is appropriately managed perioperatively.

Efficacy of Neuromodulation Interventions for the Treatment of Sexual Dysfunction: A Systematic Review.

OBJECTIVES: The primary aim of this review was to analyze the literature for the efficacy of neuromodulation interventions in treating both male and female sexual dysfunction. MATERIALS AND METHODS: Studies were identified from PubMed, Scopus, PsychINFO, CINAHL, and Cochrane. Results were synthesized qualitatively without pooling owing to the heterogeneous nature of outcome assessments. RESULTS: Overall findings from studies generally supported that neuromodulation interventions were associated with improvement in sexual function. Specific domains that improved in male patients included erectile function, desire, and satisfaction, whereas desire, arousal, orgasm, lubrication, quality of "sex life," intercourse capability, and dyspareunia improved in female patients. Male ejaculation, orgasm, and intercourse capability were the only domains that continued to decline after the use of neuromodulation interventions, although this was only reported in one study. CONCLUSION: Our review suggests that there may be promise and potential utility of neuromodulation in improving sexual dysfunction; however, further research is needed.

Cervical Spinal Cord Stimulation for the Treatment of Headache Disorders: A Systematic Review.

OBJECTIVES: Chronic headache remains a major cause of disability and pain worldwide. Although the literature has extensively described pharmacologic options for headache treatment and prophylaxis, there remains a paucity of data on the efficacy of neuromodulation interventions for treatment of headache unresponsive to conventional pharmacologic therapy. The primary aim of this review was to appraise the literature for the efficacy of cervical spinal cord stimulation (cSCS) in treating any intractable chronic headache, including migraine headaches (with or without aura), cluster headache, tension headache, and other types of headaches. MATERIALS AND METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we performed a systematic review by identifying studies in PubMed, Embase (Scopus), Web of Science, and Cochrane Central Register of Controlled Trials that assessed cSCS to treat chronic headache. Data were synthesized qualitatively, with primary outcomes of headache intensity and frequency. The secondary outcome was adverse effects. RESULTS: In total, 16 studies comprising 107 patients met the inclusion criteria. Findings were presented based on type of headache, which included migraine headache with or without aura, cluster headache, trigeminal neuropathy, occipital neuralgia, posttraumatic headache, cervicogenic headache, short-lasting unilateral neuralgiform headache with autonomic symptoms, and poststroke facial pain. Per the Grading of Recommendations, Assessment, Development and Evaluations criteria, there was very low-quality evidence that cSCS is associated with a decrease in migraine headache frequency, migraine headache intensity, and trigeminal neuropathy intensity. Placement for cSCS leads ranged from C1 to C4. CONCLUSIONS: Our review suggests promising data from observational studies that cSCS may be helpful in decreasing frequency and intensity of chronic intractable headache. Future well-powered, randomized controlled trials are needed.

A Bibliometric Analysis of Top-Cited Journal Articles Related to Neuromodulation for Chronic Pain.

OBJECTIVES: Since its foundation in the 1960s, neuromodulation has become an increasingly used treatment option for chronic pain. This bibliometric analysis examines the most cited research in this field with the aim of uncovering existing trends and future directions. MATERIALS AND METHODS: Clarivate's Web of Science data base was searched for the top 25 most cited studies focusing on neuromodulation for chronic pain. Various bibliometric parameters were then extracted and analyzed. Randomized controlled trials (RCTs) were compared with non-RCTs. RESULTS: The top 25 articles had a mean of 347 citations and 22.2 citations per year, with more recent articles having a higher citation rate. Most were published in the last two decades and predominantly originated from the United States. There were 13 RCTs, which were significantly more recent (p = 0.004) and more cited per year (p = 0.001) than the 12 non-RCTs. Sources included 15 journals with a mean impact factor of 13.896. The most studied modality was spinal cord stimulation with 20 articles (76.9%), followed by intrathecal drug delivery (15.4%), dorsal root ganglion stimulation (3.8%), and peripheral nerve stimulation (3.8%). CONCLUSIONS: Analysis of the most cited articles on neuromodulation reveals a focal shift from historical reports to innovative RCTs that have increasingly guided pain practice in the recent years. As novel techniques and technologies continue to develop, high-quality evidence coupled with broadening indications will likely direct further expansion of this field.