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

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

Comparative Descriptive Analysis of Physician Versus Patient-Directed Gabapentin Usage In Chronic Pain - A Preliminary Report.

BACKGROUND: Gabapentin is one of the most common medications employed in Pain Medicine, specifically targeting the management of neuropathic pain. We are most familiar with the incremental dosing strategy where a ceiling dose is eventually attained guided by efficacy and patient tolerance, after which a fixed dosing regimen is prescribed. We propose that autonomous short-term dose variations per patient could have rapid clinically significant effects in the management of chronic pain. OBJECTIVES: This study examines the frequency at which patients take gabapentin on a fixed vs variable schedule and how the pattern of gabapentin use correlates with efficacy, side effects, and patient satisfaction. STUDY DESIGN: Single institution, cross-sectional observational survey study with data collection performed over 2 phases as a pilot for proof of concept. SETTING: Remote contact via telephone with researchers calling from a quiet, private location within the hospital complex conducive for confidential conversation. METHODS: Patients recently prescribed gabapentin were queried on the patterns of use and self-perceived efficacy, satisfaction, and side effects in accordance to a standardized oral script. Patients selected met the criteria of being new patients freshly prescribed gabapentin who have been consistently on the medication for at least a month, while having chronic pain symptoms for over 3 months. Responses were collected in the form of a 5-point Likert scale. Statistical analyses were performed using GraphPad Prism. RESULTS: Of the 222 patients, 92 patients agreed to participate in the survey for a response rate of 41.4. Of these, 51% had terminated the medication for various reasons. Of the patients still taking gabapentin, 73% were on a fixed schedule, while 27% were on a variable dosing schedule. Variable dosing cohort reported better efficacy (P = 0.027) and satisfaction (P = 0.036), while the side-effect profile between the 2 groups was similar. LIMITATIONS: The study is limited by its nature of being a pilot, single-institution study performed on a relatively small sample size. None of the patients we surveyed had been given the autonomy to adjust gabapentin doses by their providers and this could significantly reduce the proportion of patients who would be encouraged to run a variable dosing regimen. CONCLUSIONS: This pilot study suggests that a significant portion of patients choose to administer variable doses of gabapentin and associate this with better efficacy and satisfaction. A larger study is needed to confirm this supposition. Based upon this pilot study, the variable dosing option may be an option for improved therapeutic efficacy or as an alternative to those whose lifestyles do not allow for fixed dosing regimens. Discussion of the risks of gabapentin, including respiratory depression, and clear dosage parameters of use, would need to be outlined when considering a variable dose regimen.

The contralateral oblique fluoroscopic view is associated with a lower incidence of postdural puncture headache in patients undergoing percutaneous spinal cord stimulation.

BACKGROUND: Spinal cord stimulation (SCS) is a minimally invasive therapy that is increasingly used to treat refractory neuropathic pain. Although this technique has a low incidence of serious long-term adverse sequelae, the risk of complications such as inadvertent dural puncture remains. OBJECTIVES: The goal of this article was to determine the impact of the contralateral oblique (CLO) fluoroscopic view incidence of postdural puncture headache (PDPH) during spinal cord stimulator implantation as compared to lateral fluoroscopic view. METHODS: This was a single academic institution retrospective analysis of electronic medical records spanning an approximate 20-year time period. Operative and postoperative notes were reviewed for details on dural puncture, including technique and spinal level of access, the development of a PDPH, and subsequent management. RESULTS: Over nearly two decades, a total of 1637 leads inserted resulted in 5 PDPH that were refractory to conservative measures but responded to epidural blood patch without long-term complications. The incidence of PDPH per lead insertion utilizing loss of resistance and lateral fluoroscopic guidance was 0.8% (4/489). However, adoption of CLO guidance was associated with a lower rate of PDPH at 0.08% (1/1148), p < 0.02. CONCLUSIONS: The incorporation of the CLO view to guide epidural needle placement can decrease the odds of a PDPH during percutaneous SCS procedures. This study further provides real-world data supporting the potential enhanced accuracy of epidural needle placement in order to avoid unintentional puncture or trauma to deeper spinal anatomic structures.

A Survey on the Choice of Spinal Cord Stimulation Parameters and Implantable Pulse Generators and on Reasons for Explantation.

Objective: Spinal Cord Stimulation (SCS) is a vital treatment for chronic intractable pain. In the last few years, the field has undergone dramatic changes in new waveform and frequency introduction as well as device miniaturization. It is important to understand contemporary practice patterns regarding these parameters. Methods: We surveyed the active membership of Spine Intervention Society (SIS), and American Society of Regional Anesthesia (ASRA) on their practices regarding various aspects of Spinal Cord Stimulation therapy. Here we report on SCS waveform usage, battery types, and causes of explant in this cohort of providers. Results: There was similar degree of usage of tonic, burst, and 10 kHz usage at 71.5%, 74.1% and 61.7% respectively. Dorsal root ganglion stimulation was used by 32.6% and other modes of stimulation by 13.5%. Rechargeable systems were often or always used by 67.2% whereas 10% never used a rechargeable system. Most common cause of explant was loss of effectiveness, reported by 53.7%. Conclusion: There has been significant adoption of new waveforms in daily practice of spinal cord stimulation therapy and there is robust mixed usage of new waveforms and frequencies. Rechargeable systems are the most commonly used but primary cell is also used in significant numbers. Loss of efficacy remains the most common cause of explant for the majority of practitioners. This survey establishes practice patterns of SCS usage regarding these important variables against which future changes can be gauged.

The Evolving Role of High-Frequency Spinal Cord Stimulation as Salvage Therapy in Neurostimulation.

BACKGROUND: High-frequency 10-kHz spinal cord stimulation (10-kHz SCS) has shown promise in multicenter prospective trials for the management of chronic back and leg pain. Traditional spinal cord stimulation (t-SCS) has a long history of effectiveness in chronic neuropathic syndromes but not uncommonly can fail to provide long-term relief, leaving a significant group of patients with unsatisfactory outcomes. There is mounting evidence that 10-kHz SCS may offer relief in this subset of patients. METHODS: The purpose of this retrospective analysis was to report a single-institution long-term experience of 10-kHz SCS in patients who did not get adequate pain relief with prior t-SCS devices. A temporary trial of 10-kHz SCS was carried out for 7 days, and those experiencing an average of 50% reduction in pain intensity underwent implantation. Patients were classified as moderate responders if relief was 31% to 50% and excellent responders if pain relief exceeded 50%. RESULTS: Thirty-one patients who had experienced failed t-SCS primarily from poor paresthesia coverage underwent a trial of 10-kHz SCS and 29 underwent implantation. Twenty-eight patients were available for analysis, with 57.1% experiencing 30% response and 46.4% experiencing excellent response at a median follow-up of 21.2 (±8.4) months. CONCLUSIONS: This small single-institution study suggests that a significant proportion of patients with previously failed t-SCS may achieve clinically meaningful and durable pain relief with 10-kHz SCS.

Depression Trends in Patients with Chronic Pain: An Analysis of the Nationwide Inpatient Sample.

BACKGROUND: Chronic pain remains a major public health issue that affects the lives of many worldwide, including patients with chronic pain. Comorbidities like depression have been associated with decreased quality of sleep, decreased enjoyment of life activities, increased anxiety, and decreased efficacy in treatments among patients with chronic pain. Despite these associations, the trends and demographic characteristics of patients with chronic pain with depression is yet to be investigated. OBJECTIVES: To investigate the trends and demographic characteristics of hospitalized patients with chronic pain with comorbid depression from years 2011 to 2015 in the United States. STUDY DESIGN: This was an observational study. SETTING: Patients were identified from a Healthcare Cost and Utilization Project database called National Inpatient Sample (NIS) documentation. METHODS: Patients were identified from the NIS database using International Classification of Diseases, Ninth and Tenth Revision (ICD-9 and ICD-10) diagnosis codes for chronic pain and comorbid depression from years 2011 to 2015. RESULTS: Between 2011 and 2015, an estimated 9.3 million patients with chronic pain were identified. Of this cohort, 2.2 million patients (22.9%) were diagnosed with comorbid depression. The estimated number of patients with depression varied from 399,865 (22.6%) in 2011 to 421,490 (23.1%) in 2015 (P = 0.13). From 2011 to 2015, there was a significant upward trend of depression among blacks (8.1 ± 0.42% to 9.7 ± 0.27%), patients aged 65 to 84 years (29.0 ± 0.39% to 32.4 ± 0.23%), Medicare insured patients (56.1 ± 0.54% to 58.5 ± 0.29%), Medicaid insured patients (14.7 0.4% to 17.1 ± 0.24%), and patients from zip code areas with lowest annual household income (29.2 ± 1.3% to 32.0 ± 0.59%). Among patients with depression, the adjusted total hospitalization cost increased from $43,584 in 2011 to $49,923 in 2015 (P < 0.001), with average length of hospital stay stable around 5.05 ± 0.02 days. Most patients were discharged home or with self-care compared with short-term facility (57.9 ± 0.14% vs. 2.0 ± 0.03%). LIMITATIONS: Large database research comes with several limitations. The NIS database does not contain variables that can evaluate disease severity such as depression. In addition, the NIS database is highly dependent on the selection and report accuracy of the appropriate diagnostic ICD codes. These estimates could be imprecise from over or underestimation of the number of patients with chronic pain with comorbid depression. CONCLUSIONS: These findings from the present investigation suggest that depression in patients with chronic pain remained stable from 2011 to 2015, with the majority of patients identified as women, white, and ages 45 to 65 years. KEY WORDS: Chronic pain, depression, National Inpatient Sample.

Discontinuation of Chronic Opiate Therapy After Successful Spinal Cord Stimulation Is Highly Dependent Upon the Daily Opioid Dose.

OBJECTIVES: The aim of this study was to determine if any of the factors recorded on a standard clinical history of a patient considered for spinal cord stimulation (SCS) would be associated with reduction or cessation of opioids following implantation. DESIGN: Retrospective, single academic center. METHODS: Patients included in the chart analysis underwent implantation of percutaneous SCS devices from 1999 to 2015 with follow-up until the end of September 2018. Patients who achieved at least an average of 50% pain reduction were included for analysis of daily opioid intake. Patients were then divided into 4 groups that included no opioid use, stable opioid daily dose, weaned opioid dose, and complete cessation of opioids. Statistical methods were used to analyze for associations between opioid intake after SCS insertion and usual elements of a clinical history, including adjuvant medications, numeric pain rating, past medical history, psychiatric illness, substance abuse, employment, and smoking history. RESULTS: In a group of 261 patients who had undergone implantation, 214 met the criteria for analysis and had a median age of 50 years, with majority having the diagnoses of failed back surgery syndrome and complex regional pain syndrome. The only factor that was associated with complete cessation of opioid use was a median dose of 30 mg of morphine per day (P < 0.01) and was observed in 15% of subjects who used opioids preoperatively. CONCLUSION: The elimination of opioid dependence following initiation of SCS therapy is highly dependent on the daily dose.

An Atypical Presentation of Raynaud's Disease.

OBJECTIVE: A 57-year-old female with a 33-year history of constant hand discoloration and paronychia had undergone multiple evaluations with a failure to find a diagnosis. She continues to undergo an evolving treatment regimen and diagnostic workup in an effort to find a long-eluded diagnosis. CLINICAL PRESENTATION: She began to develop superficial ulcerations over the proximal phalanx of her fingers, often pruritic and erythematous, with pain and edema. INTERVENTION: She has since been managed with nifedipine and sildenafil and intermittent stellate ganglion blocks. CONCLUSION: Despite still lacking a formal diagnosis, her constellation of symptoms is most likely the result of an atypical presentation of Raynaud's disease.

Explantation of Percutaneous Spinal Cord Stimulator Devices: A Retrospective Descriptive Analysis of a Single-Center 15-Year Experience.

OBJECTIVES: The aims of this study were to identify the reasons for explanation of spinal cord stimulator (SCS) devices and to further quantify the proportions and time lines of these causes of explantation in order to determine improvement opportunities for the development of best practices. DESIGN: Retrospective, single academic center. MATERIALS AND METHODS: Patients who were implanted with percutaneous SCS devices from 2002 to 2015 and with follow-up available until the end of September 2017 were included in this retrospective chart analysis. RESULTS: Of the 356 patients trialed, 252 underwent implantation of an SCS device with a permanent to trial ratio of 71%. Of the patients who had a permanent implant, 50% had failed back surgery syndrome, 25% had complex regional pain syndrome, and 25% had other diagnoses. At the end of the study period, the explantation rate was 30%. The causes for explantation included biological complications (26.6%), paresthesia limitations or side effects (26.6%), hardware complications (13.3%), ineffective pain control (28%), and no further need for stimulation therapy (5.3%). CONCLUSIONS: Device removal is not uncommon, and opportunities to enhance the long-term success of SCS devices do exist. These include modification of trialing methods, achieving better paresthesia overlay, using magnetic resonance imaging (MRI) conditional equipment, development of robust technologies and hardware to reduce equipment malfunction, and improving efficacy with new innovative wave forms.

High-Frequency Spinal Cord Stimulation at 10 kHz for the Treatment of Complex Regional Pain Syndrome: A Case Series of Patients With or Without Previous Spinal Cord Stimulator Implantation.

BACKGROUND: High-frequency spinal cord stimulation at 10 kHz (HF10-SCS) has been demonstrated to provide enhanced and durable pain relief in patients with chronic back and radiating leg pain. Patients with pain related to complex regional pain syndrome (CRPS) in the chronic stages are commonly challenging to treat and often receive traditional spinal cord stimulation (SCS). Very little information is currently available about the therapeutic outcomes following application of high-frequency stimulation in this cohort of patients. METHODS: The purpose of the retrospective case series was to report on the initial experience of HF10-SCS in 13 patients with CRPS, some of whom had been exposed to low-frequency SCS. A temporary trial of HF10-SCS was carried out for 1 week, and those achieving a minimum of 50% pain intensity reduction underwent implantation. Successful responders were those who achieved a 50% decrease in pain intensity on subsequent follow-up. RESULTS: Thirteen patients were trialed, 12 of whom went on to receive a permanent implant. Of the patients receiving permanent implants, the responder rate (50% pain relief) was 67% (95% confidence interval [CI] 0.34 to 0.90), with an average follow-up period of 12.1 ± 4.6 months. Of the 5 patients who had sympathetically independent pain, 3 were responders, and of the 7 patients who had sympathetically mediated pain, 5 were responders. There were no adverse events. CONCLUSION: This small case series suggests that HF10-SCS may be a viable option for patients with CRPS who have chronic intractable pain, including those who had suboptimal results from traditional SCS.

A Brief History of the Opioid Epidemic and Strategies for Pain Medicine.

The opioid epidemic has resulted from myriad causes and will not be solved by any simple solution. Consequent to a staggering increase in opioid-related deaths in the USA, various governmental inputs and stakeholder strategies have been proposed and implemented with varying success. This article summarizes the history of opioid use and explores the causes for the present day epidemic. Recent trends in opioid-related data demonstrate an almost fourfold increase in overdose deaths from 1999 to 2008. Tragically, opioids claimed over 64,000 lives just last year. Some solutions have undergone legislation, including the limitation of numbers of opioids postsurgery, as well as growing national prevalence of enhanced recovery after surgery protocols which focus on reduced postoperative opioid consumption and shortened hospital stays. Stricter prescribing practices and prescription monitoring programs have been instituted in the recent past. Improvement in abuse deterrent strategies which is a major focus of the Food and Drug Administration (FDA) for all opioid preparations will likely play an important role by increasing the safety of these medications. Future potential strategies such as additional legislative policies, public awareness, and physician education are also detailed in this review.

Guidelines for Composing and Assessing a Paper on the Treatment of Pain: A Practical Application of Evidence-Based Medicine Principles to the Mint Randomized Clinical Trials.

Objective: To perform a thorough assessment of the recently published Mint Trials in order to illustrate how to read and analyze a study critically, according to principles of evidence-based medicine. Design: Narrative review. Method: We have applied the recently published guidelines for composing and assessing studies on the treatment of pain to a recently published article describing a large study that claimed its "findings do not support the use of radiofrequency denervation to treat chronic low back pain." These guidelines describe the critical components of a high-quality manuscript that allows communication of all relevant information from authors to readers. Results: Application of evidence-based medicine principles to the publication describing the Mint Trials reveals significant issues with the methodology and conclusions drawn by the authors. A thorough assessment demonstrates issues with inclusion/exclusion criteria, diagnostic block protocols, radiofrequency neurotomy technique, co-interventions, outcome measurement, power analysis, study sample characteristics, data analysis, and loss to follow-up. A failure to definitively establish a diagnosis, combined with use of an inadequate technique for radiofrequency neurotomy and numerous other methodological flaws, leaves the reader unable to draw meaningful conclusions from the study data. Conclusions: Critical analysis, rooted in principles of evidence-based medicine, must be employed by writers and readers alike in order to encourage transparency and ensure that appropriate conclusions are drawn from study data.

The Long-Term Durability of Multilumen Concentric Percutaneous Spinal Cord Stimulator Leads.

BACKGROUND: Lead fracture is a well-known complication of cylindrical spinal cord stimulator leads. In order to reduce this complication, anchor design and techniques have been modified, but internal lead design has received little attention. OBJECTIVES: The goal of this study was to study the impact of lead design by a retrospective determination of the fracture rate of multilumen concentric (MLC) 8-contact leads. STUDY DESIGN: Retrospective chart review. SETTING: University teaching hospital. METHODS: A registry of spinal cord stimulator implants and corresponding billing data were used to identify patients. Procedural details were reviewed for technique, lead insertion, anchoring details, manufacturer, and lead longevity from 2002 to 2014. Data storage was in RedCap data-capturing software (REDCap eData Collection web-based application). All analyses were performed using SAS 9.3 (SAS Institute, Cary, NC, U.S.A.). RESULTS: In a near 12"-year time period, 172 patients received 305 permanently implanted 8-contact leads, with an overall fracture rate of 4.3%. Of these, 191 leads were of the MLC design. No lead fracture was observed in the MLC leads over an average 4.5 years of follow-up. LIMITATION: Retrospective single center. CONCLUSION: MLC lead design has the potential to significantly mitigate lead fracture.

Prospective Assessment of Pain and Comfort in Chronic Pain Patients Undergoing Interventional Pain Management Procedures.

Objective: Interventional pain management procedures have an important role in the management of chronic pain. The present study seeks to identify the proportion of patients who experience severe pain during pain procedures either with or without sedation. There is then an attempt to identify any association of high pain levels with factors such as age, gender, ethnicity, preprocedure pain level, procedure type, tobacco use, and baseline pharmaceuticals taken for both pain and/or mood disorder management. Methods: This is a prospective survey study evaluating patients' discomfort during interventional pain procedures in an outpatient academic facility. Patient discomfort was assessed by the PROcedural Sedation Assessment Survey (PROSAS) and modified for nonsedation cases. Results: There were 155 patients in the survey, with 20 of these receiving nonspinal injections. Of the remaining 135 patients who underwent spinal injections, only 10 received conscious sedation. On average, 14.2% experienced severe pain during spinal injections, whereas 20% experienced severe pain with nonspinal injections. Though few patients received conscious sedation, most of these (60%) experienced high levels of pain. There was no correlation between level of procedural pain with age, gender, ethnicity, preprocedure pain level, procedure type, tobacco use, or medication type used. Conclusions: The majority of patients who undergo nonsedated interventional pain management procedures do not experience severe pain. There is a small but appreciable group of subjects who seem to experience severe pain that cannot be correlated to any particular clinical characteristic in a standard patient evaluation. Even with standard conscious sedation, there is no clear best method to ensure patient comfort for this high-pain level group.

Treatment of Chronic Refractory Neuropathic Pelvic Pain with High-Frequency 10-kilohertz Spinal Cord Stimulation.

Chronic neuropathic pelvic pain remains a recalcitrant problem in the field of pain management. Case series on application of 10 kHz spinal cord stimulation is presented. High frequency stimulation can improve chronic neuropathic pain states that are known to be mediated at the conus medullaris and offers another avenue for the treatment of these patients.

A Temporary vs. Permanent Anchored Percutaneous Lead Trial of Spinal Cord Stimulation: A Comparison of Patient Outcomes and Adverse Events.

OBJECTIVES: A trial of spinal cord stimulation (SCS) is a prerequisite to determine efficacy of the therapy prior to placement of a permanent implanted system. A trial may be conducted employing a percutaneously placed temporary cylindrical lead or via a permanently anchored cylindrical lead placed and subsequently secured via open surgical method. There has been little investigation comparing the two methods of trial. This study is a comparative analysis of the two methods both for prediction of success as well as associated morbidity. STUDY DESIGN: Retrospective chart review. MATERIALS AND METHODS: SCS outcomes of percutaneous temporary lead trial or the temporary lead (TL) group and permanent anchored lead trial or permanent lead (PL) group were analyzed for lack of relief, poor paresthesia coverage, false positive trial phase, fading relief, and biological complications. RESULTS: Outcome data was analyzed for 148 patients in the TL group and 138 patients in the PL group. In comparing the two trial methods, false positive rate of trial was higher (p < 0.05) in the PL group as compared to the TL group (6.35 vs. 1.35%). Cumulative wound infections (6.52 vs. 1.35%), and poor wound healing (4.35 vs. 0%) were also significantly higher in the PL group. Rate of success in the trial phase was equal in both groups. CONCLUSION: The percutaneous temporary lead trial group was associated with fewer false positives and wound related complications as compared to permanent anchored lead trial group. There was very little technical advantage of routinely anchoring the trial lead.