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Elizabeth H Golembiewski,1 Montserrat Leon-Garcia,1– 3 Derek Loy Gravholt,1 Juan P Brito,1 Erica S Spatz,4 Markus A Bendel,5 Victor M Montori,1 Andrea P Maraboto,1 Sandra A Hartasanchez,1 Ian G Hargraves1 1Knowledge and Evaluation (KER) Unit, Mayo Clinic, Rochester, MN, USA; 2Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain; 3Department of Pediatrics, Obstetrics, Gynaecology and Preventive Medicine, Universidad Autónoma de Barcelona, Barcelona, Spain; 4Division of Cardiovascular Medicine, School of Medicine, Yale University, New Haven, CT, USA; 5Division of Pain Medicine, Mayo Clinic, Rochester, MN, USACorrespondence: Ian G Hargraves, Knowledge and Evaluation Research (KER) Unit, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA, Email hargraves.ian@mayo.eduPurpose: To compare three methods for identifying patient preferences (MIPPs) at the point of decision-making: analysis of video-recorded patient-clinician encounters, post-encounter interviews, and post-encounter surveys.Patients and Methods: For the decision of whether to use a spinal cord stimulator device (SCS), a video coding scheme, interview guide, and patient survey were iteratively developed with 30 SCS decision-making encounters in a tertiary academic medical center pain clinic. Burke’s grammar of motives was used to classify the attributed source or justification for a potential preference for each preference block. To compare the MIPPs, 13 patients’ encounters with their clinician were video recorded and subsequently analyzed by 4 coders using the final video coding scheme. Six of these patients were interviewed, and 7 surveyed, immediately following their encounters.Results: For videos, an average of 66 (range 33– 106) sets of utterances potentially indicating a patient preference (a preference block), surveys 33 (range 32– 34), and interviews 25 (range 18– 30) were identified. Thirty-eight unique themes (75 subthemes), each a preference topic, were identified from videos, surveys 19 themes (12 subthemes), and interviews 39 themes (54 subthemes). The proportion of preference blocks that were judged as expressing a preference that was clearly important to the patient or affected their decision was highest for interviews (72.8%), surveys (68.0%), and videos (27.0%). Videos mostly attributed preferences to the patient’s situation (scene) (65%); interviews, the act of receiving or living with SCS (43%); surveys, the purpose of SCS (40%).Conclusion: MIPPs vary in the type of preferences identified and the clarity of expressed preferences in their data sets. The choice of which MIPP to use depends on projects’ goals and resources, recognizing that the choice of MIPP may affect which preferences are found.Keywords: patient preferences, decision making, regulatory, preference identification, preference elicitation

Jonathan M Hagedorn, Nicholas Canzanello, Markus A Bendel, Thomas P Pittelkow, Tim J Lamer Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, 55905, USACorrespondence: Jonathan M HagedornDepartment of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, 55905, USAFax +1 507-266-7732Email jonhagedornmd@yahoo.comObjective: 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.Keywords: spinal cord stimulation, surgical site infection, outcomes, infection prevention

E Morgan Pollard,1 Tim J Lamer,2 Susan M Moeschler,3 Halena M Gazelka,3 W Michael Hooten,3 Markus A Bendel,3 Nafisseh S Warner,3 M Hassan Murad41Division of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN 55905, USA; 2Division of Pain Medicine, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN 55905, USA; 3Division of Pain Medicine, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; 4Preventive, Occupational, and Aerospace Medicine, Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN, USAObjective: To synthesize the evidence regarding the effect of spinal cord stimulation (SCS) on opioid and pain medication reduction in patients with intractable spine or limb pain.Methods: A comprehensive literature search was conducted to identify RCTs of patients with chronic back and/or limb pain of greater than one year duration. Only comparative studies were included (ie, conventional SCS vs medical therapy, conventional SCS vs high-frequency SCS) and were required to have a minimum follow-up period of 3 months. Random effect meta-an alysis was used to compare the three interventions. Results were expressed as odds ratio (OR) or weighted mean difference (WMD) with 95% confidence intervals (CI).Results: We identified five trials enrolling 489 patients. Three of the trials reported the results as a number of patients who were able to reduce or eliminate opioid consumption in the SCS vs medical therapy group. The odds of reducing opioid consumption were significantly increased in the SCS group compared to medical therapy (OR 8.60, CI {1.93–38.30}). Two of the trials reported the results as mean medication dose reduction as measured by the Medication Quantification Scale (MQS) in the SCS group vs medical therapy group. MQS score significantly decreased in the SCS group and not in the medical group (WMD –1.97, 95% CI {–3.67, –0.27}). One trial reported a number of patients in high-frequency SCS who were able to reduce opioids vs number of patients in conventional SCS group who were able to reduce opioids. Thirty-four percent of the patients in the high-frequency group and 26% of the patients in the conventional SCS group were able to reduce opioid consumption; however, there was not a significant difference between groups (OR 1.43, 95% CI {0.74, 2.78}). This trial also quantified the opioid reduction in morphine equivalent dosage (MED). In the high-frequency SCS group, average MED decreased by 24.8 mg vs average MED decrease of 7.3 mg in the conventional SCS group. Again, the difference between groups did not reach statistical significance (–17.50, CI {–66.27, 31.27}).Conclusions: In patients with intractable spine/limb pain, SCS was associated with increased odds of reducing pain medication consumption. However, results should be treated with caution as available data were limited, and clinical significance of these findings requires further study.Keywords: spinal cord stimulation, chronic back pain, painful diabetic neuropathy, chronic limb pain, high-frequency spinal stimulations, opioids, pain medications

Objective: The primary objective of this study was to quantify changes in performance of task-specific motor activities over 12 motor rehabilitation sessions with lumbosacral spinal cord stimulation (SCS) via either transcutaneous stimulation or epidural stimulation. Both stimulation modalities have been used in recent years to restore functions lost to spinal cord injury (SCI). Secondary outcomes examine participants' perspectives captured via the User Experience Questionnaire (UEQ) upon study completion to further understand their perception of SCS., Methods: Six individuals with SCI completed 12 sessions with one modality of SCS during supine and/or side-lying, seated forward reaching, and standing activities. Changes in volitional lower extremity movement, the number of points of contact needed at hips and/or knees to facilitate standing, and changes in seated forward reaching distance were used to quantify performance. The UEQ was administered to gauge participants' perspectives following use of SCS to enable functions impaired due to SCI., Results: For all participants, performance of motor activities improved with SCS compared to without stimulation. Responses for the UEQ showed an overall positive perception of trialing SCS with rehabilitation to enhance motor functions impaired by SCI., Conclusions: Regardless of injury severity, location of injury, time since SCI, or SCS modality, all participants experienced gains in motor function in the presence of SCS combined with a condensed rehabilitation program. However, no evidence of sustained motor functions was found in the absence of SCS. UEQ results highlight the positive perception of SCS with rehabilitation as well as the importance of consulting persons with lived experience of SCS during clinical trial design and protocol development. Trial registration: ClinicalTrials.gov identifier: NCT05095454.

Objective: Randomized trials have demonstrated efficacy of spinal cord stimulation (SCS) for treatment of painful diabetic neuropathy (PDN). Preliminary data suggested that treatment of PDN with high-frequency SCS resulted in improvements on neurological examination. The purpose of the present study was to explore whether patients with PDN treated with high-frequency SCS would have improvements in lower-extremity peripheral nerve function., Design: Prospective cohort study in an outpatient clinical practice at a tertiary care center., Methods: Patients with PDN were treated with high-frequency SCS and followed up for 12 months after SCS implantation with clinical outcomes assessments of pain intensity, neuropathic symptoms, and neurological function. Small-fiber sudomotor function was assessed with the quantitative sudomotor axon reflex test (QSART), and large-fiber function was assessed with nerve conduction studies (NCS). Lower-extremity perfusion was assessed with laser Doppler flowmetry., Results: Nine patients completed 12-month follow-up visits and were observed to have improvements in lower-extremity pain, weakness, and positive sensory symptoms. Neuropathy impairment scores were improved, and 2 patients had recovery of sensory responses on NCS. A reduction in sweat volume on QSART was observed in the proximal leg but not at other sites. No significant differences were noted in lower-extremity perfusion or NCS as compared with baseline., Conclusions: The improvement in pain relief was concordant with improvement in neuropathy symptoms. The findings from this study provide encouraging preliminary data in support of the hypothesis of a positive effect of SCS on peripheral neuropathy, but the findings are based on small numbers and require further evaluation., Trial Registration: ClinicalTrials.gov ID NCT03769675., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: Appropriate spinal cord stimulation (SCS) candidates are required to undergo an SCS trial before implant, typically with ≥50% pain relief deemed "successful." However, SCS trialing protocols can vary substantially. The primary aim of this retrospective study is to investigate the associations between SCS trial results and long-term SCS pain outcomes., Materials and Methods: This study was a retrospective single-center review of successful SCS trials from January 1, 2017, to July 1, 2019. A total of 115 patients were included. Group differences in continuous variables were evaluated using t-tests, and group differences in categorical variables were evaluated using the χ 2 test. The percentage improvement in long-term pain intensity was analyzed as a binary variable, where long-term success was defined as ≥50% improvement in numeric rating scale pain scores. The level of significance for all tests was set at p < 0.05., Results: The mean age was 64.9 years, and 52% of patients were men. The mean pain score at long-term follow-up was 4.7 ± 2.6, and the median time from implantation to follow-up was 13 months (25th-75th interquartile range; 4-22). In the logistic regression analysis adjusted for age, sex, and follow-up time, greater patient-reported percentage improvement in pain scale during the trial was significantly associated with greater odds of experiencing ≥50% improvement in pain scores (p = 0.048; 95% CI 1.00-1.70). All other assessed trial metrics were not significantly associated with greater odds of experiencing >50% improvement in pain scores at last follow-up., Conclusions: Given the variability in current assessment techniques, we recommend the patient-reported percentage improvement in pain scale as the posttrial assessment method of choice instead of a calculated percentage improvement. However, our results indicate that current trial assessment methods are generally poor, and improved trial reporting protocols must be sought., (Copyright © 2022 International Neuromodulation Society. Published by Elsevier Inc. All rights reserved.)

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., (© 2022 World Institute of Pain.)

Background and Objectives: Dorsal root ganglion stimulation (DRGS) is a newer form of neuromodulation that targets the dorsal root ganglion. DRGS has superior efficacy in complex regional pain syndrome compared to spinal cord stimulation (SCS) and may have efficacy in other forms of chronic pain. While decades of safety data are available for SCS, there is less available safety information for DRGS. The objectives of this systematic review and pooled analysis of incidence are to determine the overall incidence of DRGS infections, incidence at each stage (trial vs implant vs revision), infection characteristics, and outcomes., Materials and Methods: A comprehensive search of databases from January 1980 to January 2021 was conducted., Results: Ten studies met inclusion criteria. Eight studies reported patients with trial data (n = 291), ten studies reported patients with implant data (n = 250), and seven studies reported data with revisions (n = 26). The pooled incidence of trial infections was 1.03% (95% CI 0.35-2.99%), implant infections was 4.80% (95% CI 2.77-8.20%), revision infections was 3.85% (95% CI 0.20-21.59%), and overall infections was 2.82% (95% CI 1.62-4.54%). There was a statistically significant difference in infection rates between the trial, implant, and revision stages, X 2 (2, N = 567) = 8.9839, p = 0.01., Conclusions: This is the first systematic review and pooled analysis that followed PRISMA guidelines to report infectious complications of DRGS by stage (trial vs implant vs revision). DRGS trial appears to be low risk for infection but that risk is significantly increased with DRGS implant. Our findings highlight the need for further study of infectious complications, their risks, and optimal prophylaxis., (Copyright © 2022 International Neuromodulation Society. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2022 International Neuromodulation Society. Published by Elsevier Inc. All rights reserved.)

Shoulder arthroplasty is a successful surgical procedure for several conditions when patients become refractory to conservative management modalities. Unfortunately, some patients experience persistent chronic pain after shoulder arthroplasty. These individuals should undergo a comprehensive evaluation by an orthopedic surgeon to determine whether structural pathology is responsible for the pain and to decide whether reoperation is indicated. At times, a surgical solution does not exist. In these circumstances, a thorough and specific plan for the management of persistent chronic pain should be developed and instituted. In this article, we review common reasons for persistent pain after shoulder arthroplasty and outline the evaluation of the painful shoulder arthroplasty. We then provide a thorough review of interventional pain management strategies. Finally, we hypothesize developments in our field that might provide better outcomes in the future for patients suffering with chronic intractable pain after shoulder arthroplasty., (© 2022 The Author(s).)

Objectives: The purpose of this single center, prospective randomized controlled trial was to compare clinical outcomes between an ultrasound-guided greater occipital nerve block (GONB) at the C2 vertebral level versus landmark-based GONB at the superior nuchal line., Methods: Patients with occipital neuralgia or cervicogenic headache were randomized to receive either a landmark-based GONB with sham ultrasound at the superior nuchal line or ultrasound-guided GONB at the C2 vertebral level with blinding of patients and data analysis investigators. Clinical outcomes were assessed at 30 minutes, 2 weeks, and 4 weeks postinjection., Results: Thirty-two patients were recruited with 16 participants in each group. Despite randomization, the ultrasound-guided GONB group reported higher numeric rating scale (NRS) scores at baseline. Those in the ultrasound-guided GONB group had a significant decrease in NRS from baseline compared with the landmark-based GONB group at 30 minutes (change of NRS of 4.0 vs. 2.0) and 4-week time points (change of NRS of 2.5 vs. -0.5). Both groups were found to have significant decreases in Headache Impact Test-6. The ultrasound-guided GONB had significant improvements in NRS, severe headache days, and analgesic use at 4 weeks when compared with baseline. No serious adverse events occurred in either group., Conclusions: Ultrasound-guided GONBs may provide superior pain reduction at 4 weeks when compared with landmark-based GONBs for patients with occipital neuralgia or cervicogenic headache., Competing Interests: J.M.H. reports personal fees from Abbott, Boston Scientific, and Nevro that are outside of the submitted work. M.J.P. reports participation on WAPMU Board of Directors, but outside the submitted work. N.R.K. serves on the editorial board for Pain Medicine also reports grant from Nevro Corporation and personal fees from UpToDate that are outside the submitted work. The remaining authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Implantable pulse generator (IPG) site pain following neuromodulation procedures is a recognized complication. The site of the IPG placement varies depending on the neuromodulation type and physician preference. The incidence of IPG site pain as a function of the site of IPG implantation has not been studied systematically., Materials and Methods: We performed a multicenter cross-sectional survey of the incidence, severity, and quality of IPG site pain, location of the IPG, the pain management needs, functional impairment, and cosmetic appearance related to the IPG placement. Contingency table analysis was conducted for categorical variables, and logistic regression analysis and linear regression model was used., Results: The survey response rate was 60.5% (n = 510). Overall, 31.0% of patients reported pain at the IPG site in the last 72 hours with 31.4% reporting moderate to severe pain and 7.6% reporting severe pain. Older age was inversely associated with IPG-related pain (OR = 0.97, 95% CI = 0.96-0.99, p = 0.001). IPG implantation site did not have a statistically significant interaction with IPG site pain (p > 0.05). The most important factor for IPG site-associated pain was having a spinal cord stimulator implanted as compared to a deep brain stimulator, or sacral nerve stimulator. Most subjects reported no functional impairment related to IPG site pain (91%), found the IPG site pain as expected (80%), and found IPG site cosmetic appearance as expected (96%)., Conclusions: The incidence of IPG site pain is an important complication of invasive neuromodulation. The anatomic location of the IPG placement does not appear to affect the incidence or severity of IPG site pain. However, the presence of a pre-implant chronic pain disorder does appear to affect the frequency and severity of IPG site pain., (© 2020 International Neuromodulation Society.)

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., (© 2021 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals LLC on behalf of International Neuromodulation Society.)

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., (© 2021 International Neuromodulation Society.)

Spinal cord and dorsal root ganglion stimulation are minimally invasive surgical techniques used to treat an array of chronic pain disorders. There is a paucity of data related to defining best practices in these specific patient populations, and historically, providers have relied on consensus committees to opine on the best techniques for patient safety and experience. The most efficacious mechanism of surgical closure-specifically a running suture closure compared to a surgical staple closure-is debated. A retrospective review of 155 patients implanted with either a spinal cord or dorsal root ganglion stimulator between 2017 and 2019 was undertaken to determine if the type of surgical closure was related to degree of postoperative surgical site discomfort. The primary outcome showed no statistically significant difference on postoperative pain scores between the suture (6.0 (IQR 5.0-8.0)) and staple (7.0 (IQR 5.0-8.0)) cohorts at postoperative day (POD) #1 (adjusted β 0.17 (95% CI -0.61 to 0.95), P =0.670). This finding held for postoperative pain scores at POD #10 as well (staples (1.0 (IQR 0.0-4.0)) and suture (2.0 (IQR 0.0-5.0), adjusted β -0.39 (95% CI -1.35 to 0.58), P =0.432)). A regression analysis was performed to identify secondary factors impacting postoperative pain scores. Higher preoperative pain score ( β 0.50 (95% CI 0.09 to 0.92), P =0.019) and female gender ( β 1.09 (95% CI 0.15 to 2.02), P =0.023) were predictive of higher incisional pain scores at POD#10. Increasing age was associated with decreased incisional pain scores at POD#10 ( β -0.06 (95% CI -0.09 to -0.03), P < 0.001). These findings are of interest to the pain practitioner and may be valuable in preoperative discussions with prospective patients., Competing Interests: JMH is a consultant for Abbott, Boston Scientific, and Nevro. He serves on advisory boards for Boston Scientific and Nevro. MAB has funded research with Nevro. All the other authors declare that they have no conflicts of interest., (Copyright © 2021 Markus A. Bendel et al.)

Abstract: The primary aim of this randomized clinical trial is to investigate the effects of ultrasound-guided transversus abdominis plane (TAP) vs ultrasound-guided trigger point injections (TPIs) on numerical rating scale pain scores at month 3 follow-up in patients with a chronic abdominal wall pain. The primary outcome measure was the difference in mean numeric rating scale pain scores between the TAP and TPI groups at month 3 in an intent-to-treat (ITT) analysis. A total of 60 patients were randomized 1:1 to receive an ultrasound-guided TAP block (n = 30) or an ultrasound-guided TPI (n = 30). No significant group differences in baseline demographic or clinical characteristics were observed. The mean baseline pain score for the TAP and TPI groups was 5.5 and 4.7, respectively. In the ITT analysis at month 3, the between-group difference in pain scores was 1.7 (95% confidence interval, 0.3-3.0) favoring the TPI group. In a secondary per-protocol analysis, the between-group difference in pain scores was 1.8 (95% confidence interval, 0.4-3.2) favoring the TPI group. For the ITT and per-protocol analyses, the group differences in pain scores were consistent with a medium effect size. The main finding of this randomized clinical trial is that adults with chronic abdominal wall pain who received a TPI reported significantly lower pain scores at month 3 follow-up compared with patients who received a TAP block., (Copyright © 2021 International Association for the Study of Pain.)

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., (© 2021 International Neuromodulation Society.)

Purpose: Peripheral nerve stimulation (PNS) is a rapidly expanding field within neuromodulation; however, there is limited data on therapeutic efficacy. This study describes the indications and clinical outcomes for patients undergoing PNS for chronic pain states., Patients and Methods: This is a retrospective case series of adults undergoing PNS implantation from 2004 to 2017 at an academic medical center. The primary outcomes were changes in numeric rating scale (NRS) pain scores, opioid utilization in oral morphine milligram equivalent (MME), and self-reported patient functioning at 6 months postoperatively. Infectious and device-related complications were also assessed., Results: A total of 72 patients underwent PNS implantation, including 59 patients that received a preceding PNS trial (59/78; 76% progression rate) and 13 that did not receive a PNS trial. The most common indication for stimulation was occipital neuralgia (47%) followed by lower-extremity neuropathies (17%). PNS implantation was associated with 6-month reductions in pain scores (7 [6, 8] baseline vs. 4 [2, 5] 6 months; P < 0.001) and opioid utilization (eg, median 60 [31, 104] vs. 18 [0, 52] MME among those with baseline opioid use; P < 0.001). Median functional improvement was 73% (50%, 88%). Seven patients (10%) suffered a postoperative surgical site infection at a median of 50 (30, 124) days, of which five devices were removed., Conclusion: Peripheral nerve stimulation was associated with reduced pain scores, lower opioid utilization, and improved patient function at 6 months. These data support PNS as a potentially effective nonopioid analgesic modality in chronic pain, though prospective multicenter evaluation is warranted to evaluate longer-term outcomes., (© 2020 World Institute of Pain.)

Introduction: Spinal cord stimulation is frequently used for the treatment of intractable chronic pain conditions. Trialing of the spinal cord stimulator device is recommended to assess the patient's response to neurostimulation before permanent implantation. The trial response is often assessed by Numeric Rating Scale changes and patient-reported percentage pain improvement. Using number rating scale changes between prespinal and postspinal cord stimulation trial, a calculated percentage pain improvement can be obtained. The aim of this study was to assess the difference between calculated and patient-reported percentage improvement in pain scale during spinal cord stimulation trials., Methods: This study was a retrospective single center review of all spinal cord stimulation trials from January 1 2017 to July 1 2019. A total of 174 patients were included. The paired t-test was used to compare numeric pain scores obtained prestimulation versus poststimulation. The mean difference between methods (patient-reported minus calculated) was compared with zero using the 1-sample t-test. Lin's concordance correlation coefficient was computed with a 95% CI, calculated using Fisher z-transformation; and a bootstrapping approach was used to compare the concordance correlation coefficient between groups. In all cases, two-tailed tests were used with p<0.05 considered statistically significant., Results: Based on prestimulation and poststimulation numeric rating scale scores, the mean±SD calculated percentage improvement in pain scale was 54±28. The mean±SD patient-reported percentage improvement in pain scale was 59±25. The overall 95% limits of agreement for the two methods are -30% to +41%. The overall concordance correlation coefficient was 0.76 (95% CI 0.69 to 0.81)., Conclusion: Although the two methods are highly correlated, there is substantial lack of agreement between patient-reported and calculated percentage improvement in pain scale, suggesting that these measures should not be used interchangeably for spinal cord stimulator trial outcome assessment. This emphasizes the need for improved metrics to better measure patient response to neuromodulation therapies. Additionally, patient-reported percentage improvement in pain was found to be higher than calculated percentage improvement in pain, potentially highlighting the multidimensional experience of pain and the unpredictability of solely using Numeric Rating Scale scores to assess patient outcomes., Competing Interests: Competing interests: JMH is a consultant for Abbott, Boston Scientific and Nevro. JMH is on a product advisory board for Boston Scientific. TD is a consultant for Abbott, Medtronic (Stimgenics), Vertos, Flowonix, Saluda Medical, SpineThera, Nalu, Cornerloc, Paintec, SPR Therapeutics and Boston Scientific (Vertiflex). TD is a member of the advisory board for Abbott, Flowonix, Nalu, SPR Therapeutics and Vertiflex. TD has equity options in Vertos, SpineThera, Saluda Medical, Nalu, Paintec and Cornerloc. TD has funded research from Abbott, Mainstay Medical, Saluda Medical, SPR Therapeutics and Vertiflex. TD has a patent pending for the DRG paddle lead with Abbott. MB has funded research from Nevro. SM has funded research from Abbott. NC, SC, DRS and WMH have no competing interests., (© American Society of Regional Anesthesia & Pain Medicine 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Spinal cord stimulation (SCS) is the most utilized invasive electrical neuromodulation treatment for the management of refractory chronic pain syndromes. Infection is one of the most dreaded complications related to SCS implantation and may prevent patients from receiving adequate pain treatment, adding to the initial cost and disability. Most SCS infections present as generator pocket infection. However, delay in diagnosis may lead to complications such as meningitis, epidural abscess, and/or vertebral osteomyelitis. Early recognition of SCS-related infections and associated complications is based on clinical suspicion, laboratory testing, and appropriate diagnostic imaging. While superficial surgical site infection following SCS implant may be treated with antibiotic therapy alone, deep infection involving implant warrants device removal to achieve cure. Duration of antimicrobial therapy depends on severity of clinical presentation and presence or absence of associated complications. Several preventive strategies can be incorporated in surgical practice to reduce the risk of SCS infection., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

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.

Objective: Spinal cord stimulation (SCS) is an evidence-based therapy for the treatment of refractory pain. Current American College of Graduate Medical Education requirements for pain medicine fellowship graduation include observation of five neuromodulation cases. Matriculating fellows have varying degrees of technical skill, training, and experience. The purpose of this study was to use an innovative skill-based assessment tool using the validated Zwisch scale to evaluate fellow surgical performance during SCS cases., Design: Cross-sectional survey SETTING: Mayo Clinic, Rochester, Minnesota., Subjects: Consultant faculty (10) in the Division of Pain Medicine and pain medicine fellows (5)., Methods: A list of faculty-driven neuromodulation surgical objectives was formed and a rubric was created that focused on technical approach, imaging, epidural access and wound closure. Consultants who perform surgical cases were instructed to use the Zwisch scale as a guide to evaluate fellow surgical performance during a neuromodulation case. Faculty and fellows were surveyed before and after implementation of the tool to determine their satisfaction with use of the skill assessment tool., Results: The consultants reported they were more satisfied, consistent, and efficient with feedback provided to the trainee on every aspect of neuromodulation surgical cases. The improvement was most significant during the fellows' intraoperative skill assessment. The fellows indicated increased satisfaction, improved communication, and increased efficiency of feedback when the tool was utilized. The fellows reported greater intraoperative skill assessment and consistency of feedback provided., Conclusions: The diverse nature of primary specialty backgrounds observed in pain medicine fellowship training offers a unique opportunity to assess and improve fellow skill and surgical competence in the field of neuromodulation. Both faculty and fellows reported improved satisfaction, consistency and efficiency with feedback provided. Importantly, this pilot project observed that implementation of a skill assessment tool was beneficial for both the faculty and fellow as the feedback received was viewed as strongly beneficial to the educational experience., Competing Interests: Competing interests: None declared., (© American Society of Regional Anesthesia & Pain Medicine 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: The approach to intrathecal (IT) drug delivery malfunction is complicated, particularly for iodine-allergic patients. In these situations, the current literature has not addressed the use of IT gadolinium. Case reports exist showing severe neurotoxic manifestations with IT gadolinium use. We sought to provide a resource for chronic pain physicians treating an iodine-allergic patient and considering the use of IT gadolinium., Methods: A thorough literature search identified 11 published cases of gadolinium-induced neurotoxicity due to IT injection and those cases are described in detail. The literature was also reviewed for safe dosages of IT gadolinium., Results: After thorough review, a safe IT gadolinium dose is provided. Additionally, an algorithm was developed for the workup of an IT pump malfunction in iodine allergic patients., Conclusion: Herein, we provide guidance on IT gadolinium usage and a framework for IT pump malfunction in iodine allergic patients., (© 2019 International Neuromodulation Society.)

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., (Copyright © 2019 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)

Objectives: Exploratory research quantifying the change of spasticity among patients who underwent baclofen intrathecal drug delivery system (IDDS) implantation., Patients and Methods: 88 patients with a baclofen IDDS were identified. Patient characteristics, spasticity scores pre/post intrathecal baclofen test dose, and IDDS perioperative implantation records were collected. The primary outcome was to quantify the extent to which there was a change in Modified Ashworth Scores (MAS) pre/post-intrathecal baclofen test dose administration. Secondary outcomes included the prevalence of perioperative IDDS implantation complications., Results: The mean age at IDDS implant was 44.2 years (range, 19-71), and 62.5% were male. 45.5% had spasticity of spinal cord origin, 9% of cerebral origin, and 45.5% of other upper motor neuron dysfunction. Reduction of MAS in the spinal cord origin group was 2.6 (mean, 3.5 to 0.9), cerebral origin group was 2.9 (mean, 3.3 to 0.4), and other origin group was 2.5 (mean, 3.6 to 1.1). In all patients, post dural puncture headache was the most commonly reported complication at 22.7%., Conclusion: This report offers novel findings documenting a quantifiable change of at least two points on the MAS before and after intrathecal baclofen test dose as statistically significant and could prove to be useful information to enhance the decision making process to proceed with intrathecal baclofen beyond assessment of functional abilities., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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., (© 2017 World Institute of Pain.)

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.

Objective: We present a case report of a patient who developed an epidural hematoma following an interlaminar epidural steroid injection with no risk factors aside from old age and aspirin use for secondary prevention., Case Report: A 79-year-old man developed an epidural hematoma requiring surgical treatment following an uncomplicated interlaminar epidural steroid injection performed for neurogenic claudication. In the periprocedural period, he continued aspirin for secondary prophylaxis following a myocardial infarction., Conclusions: For patients taking aspirin for primary or secondary prophylaxis, the American Society of Regional Anesthesia and Pain Medicine antiplatelet and anticoagulation guidelines for spine and pain procedures recommend a shared assessment and risk stratification when deciding to hold the medication for intermediate-risk neuraxial procedures. Cases such as this serve to highlight the importance of giving careful consideration to medical optimization of a patient even when a low- or intermediate-risk procedure is planned.

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., (© 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Objectives: Spinal cord stimulation is an evidence-based treatment for a number of chronic pain conditions. While this therapy offers improvement in pain and function it is not without potential complications. These complications include device failure, migration, loss of therapeutic paresthesia, and infection. This article looked to establish a modern infection rate for spinal cord stimulators, assess the impact of known risk factors for surgical site infections and to determine the impact of certain preventative measures on the rate of infection., Methods: After institutional review board approval, a multisite, retrospective review was conducted on 2737 unique implants or revisions of SCS systems. Patient demographics, risk factors including diabetes, tobacco use, obesity, revision surgery, trial length, implant location, implant type, surgeon background, prophylactic antibiotic use, utilization of a occlusive dressing, and post-operative antibiotic use were recorded and analyzed., Results: The overall infection rate was 2.45% (n = 67). Diabetes, tobacco use, and obesity did not independently increase the rate of infection. Revision surgeries had a trend toward higher infection rate; however, this did not meet statistical significance. There was no difference in the rate of infection between implants performed by physicians of different base specialties, cylinder leads vs. paddle leads, or between different prophylactic antibiotics. Implants performed at academic centers had a higher rate of infection when compared to implants performed in nonacademic settings. When patients received an occlusive dressing or post-operative antibiotics they had a lower rate of infection., Conclusions: The infection rate (2.45%) reported in this study is lower than the previously reported rates (3-6%) and are on par with other surgical specialties. This study did not show an increased rate of infection for patients that used tobacco, had diabetes or were obese. It's possible that given the low overall infection rate a larger study is needed to establish the true impact of these factors on infection. In addition, this study did not address the impact of poorly controlled diabetes mellitus (elevated hemoglobin A1c) vs. well-controlled diabetes. It can be concluded from this study that utilizing an occlusive dressing over the incision in the post-operative period decreases the rate of infection and should become the standard of care. This study also demonstrated the positive impact of post-operative antibiotics in decreasing the rate of infection. Studies in other surgical specialties have not shown this impact which would suggest that further research is needed., (© 2017 International Neuromodulation Society.)

Introduction: Surgical site infection is a potential complication of spinal cord stimulator (SCS) implantation. Current understanding of the epidemiology, diagnosis, and treatment of these infections is based largely on small clinical studies, many of which are outdated. Evidence-based guidelines for management of SCS-related infections thus rely instead on expert opinion, case reports, and case series. In this study, we aim to provide a large scale retrospective study of infection management techniques specifically for SCS implantation., Methods: A multicenter retrospective study of SCS implants performed over a seven-year period at 11 unique academic and non-academic institutions in the United States. All infections and related complications in this cohort were analyzed., Results: Within our study of 2737 SCS implant procedures, we identified all procedures complicated by infection (2.45%). Localized incisional pain and wound erythema were the most common presenting signs. Laboratory studies were performed in the majority of patients, but an imaging study was performed in less than half of these patients. The most common causative organism was Staphylococcus aureus and the IPG pocket was the most common site of an SCS-related infection. Explantation was ultimately performed in 52 of the 67 patients (77.6%). Non-explantation salvage therapy was attempted in 24 patients and was successful in resolving the infection in 15 patients without removal of SCS hardware components., Discussion: This study provides current data regarding SCS related infections, including incidence, diagnosis, and treatment., (© 2017 International Neuromodulation Society.)

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., (© 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Introduction: Spinal cord stimulators (SCS) are indicated for the management of multiple pain states with strong evidence. Recent guidelines recommend discontinuing aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) for the described procedures. The goal of this investigation is to assess the rate of bleeding and neurologic sequelae in patients undergoing SCS trials and implantation., Methods: This is a retrospective review from 2005 through 2014 of all patients 18 years or older undergoing the following procedures: Percutaneous SCS implantations, SCS revisions, and SCS trials. Baseline characteristics, antiplatelet and anticoagulation medications, coagulation parameters, and procedural details were extracted. The primary outcome was the presence of a bleeding complication within 31 days of the procedure requiring emergency medicine, neurology, or neurosurgical evaluation. The neurological complication was independently categorized for its potential relationship to procedural bleeding, and periprocedural red blood cell transfusion requirements were analyzed as a secondary outcome., Results: A total of 642 percutaneous SCS procedures were performed on 421 unique patients, including 346 SCS trials, 255 SCS implantations, and 41 revision surgeries. Patients had received aspirin or NSAIDs within 7 days of needle placement for 101 procedures (15.7%). There were no bleeding or neurological complications identified in this cohort., Conclusion: Although the incidence of epidural hematoma is low, the development of bleeding complications following SCS lead placement can be devastating. In the present investigation, we identified no cases of epidural hematoma following percutaneous SCS lead placement, including more than 100 patients receiving aspirin or NSAIDs. Future investigations with larger numbers are needed to better define the relationships between periprocedural aspirin and NSAID utilization and bleeding complications., (© 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Objectives: Celiac plexus blockade has known risks including bleeding and neurologic injury because of the close proximity of vascular and neuraxial structures. The aim of this study was to determine the incidence of bleeding complications in patients undergoing celiac plexus block (CPB), with an emphasis on preprocedural antiplatelet medication use and coagulation status., Methods: This is a retrospective study from 2005 to 2014 of adult patients undergoing CPB by the pain medicine division at a tertiary care center. The primary outcome was red blood cell (RBC) transfusion within 72 hours of needle placement, with a secondary outcome of bleeding complications requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days., Results: A total of 402 procedures were performed on 298 unique patients, with 58 patients (14.4%) receiving aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) preoperatively. Five patients (1.2%) received RBC transfusion within 72 hours, of which one had received preprocedure NSAIDs. A platelet count measured within 30 days was available for 268 patients, with 7 patients (2.6%) having platelet counts of 100 × 10/L or less at the time of needle placement. A total of 187 patients had a valid preoperative international normalized ratio (INR), with 9 (4.8%) having an INR of 1.5 or higher (range, 1.5-2.6). One patient (11.1%) required RBC transfusion compared with an RBC transfusion rate of 2.3% (4 of 178) in those with normal INR (P = 0.221). We identified no bleeding complications requiring emergency medicine, neurology, or neurosurgical evaluation., Conclusions: This study suggests that CPBs may be safely performed in patients receiving aspirin and/or NSAID therapy.

A recent publication reported the incidence of postdural puncture headache (PDPH) in conjunction with intrathecal drug delivery system (IDDS) implantation to be nearly 23 percent. Many patients responded to conservative measures but a percentage needed invasive treatment with an epidural blood patch (EBP). There is limited data to describe the technical details, success rates, and complications associated with EBP in this population. This study aims to provide a retrospective report of EBP for patients suffering from PDPH related to IDDS implantation. A chart review established a cohort of patients that required EBP in relation to a PDPH after IDDS implantation. This cohort was evaluated for demographic data as well as details of the EBP including technical procedural data, success rates, and complications. All patients received a trial of conservative therapy. Standard sterile technique and skin preparation were utilized with no infectious complications. The EBP was placed below the level of the IDDS catheter in 94% of procedures. Fluoroscopy was utilized in each case. The mean EBP volume was 18.6 cc and median time of EBP was day 7 after implant. There were no complications associated with EBP. EBP appears to be an effective intervention in this subset of PDPH patients.

The aim of this study was to determine whether the magnitude of the intraocular-pressure (IOP)-lowering response in monkeys to the nonselective prostaglandin (PG)F(2a)-isopropyl ester (ie) can be reproduced by combining other PG-subtype-selective compounds. IOP was lowered by approximately 25% after 4-5 days of topical administration with latanoprost (FP agonist, 1.5 microg, q.d.), bimatoprost (prostamide, whose metabolites have been shown to be FP agonists; 9 microg, q.d.), or travoprost (FP agonist, 1.2 microg, q.d) or the EP2 agonist, butaprost (25 microg, b.i.d.). The EP1 agonist, 17-phenyl trinor (PhT) PGE2 (b.i.d.), and EP3 agonist, sulprostone (b.i.d.), had no IOP-lowering effects. The addition of butaprost, sulprostone (10 microg), or 17PhTPGE2 (25 microg) to latanoprost did not lower IOP more than latanoprost alone. However, treatment with the combination of latanoprost, 17PhTPGE2, butaprost, and sulprostone produced a similar 50-55% reduction in IOP, as did PGF(2)alpha-ie (b.i.d.). In conclusion, latanoprost, travoprost, and bimatoprost produce similar IOP-lowering responses in normotensive monkeys and are most efficacious when administered q.d. pm, compared to b.i.d. The combination of the FP, EP1, EP2, and EP3 agonists used in this study was sufficient to lower IOP by the same magnitude as PGF(2)alpha-ie, suggesting that combining PG-subtype agonists may be a potent antiglaucoma strategy.