Spinal Cord Stimulation for the Treatment of Chronic Pain Reduces Opioid Use and Results in Superior Clinical Outcomes When Used Without Opioids.

BACKGROUND: Chronic pain causes a significant burden to the US health care system, is difficult to treat, and remains a significant contributor to increased opioid use in the United States. Spinal cord stimulation (SCS) has been FDA approved for the treatment of chronic pain. OBJECTIVE: To evaluate the hypothesis that SCS reduces opioid use, and alone maintains clinical outcome measures of pain and psychosocial determinants of health. METHODS: In this prospective cohort study, we evaluated 86 patients undergoing SCS surgery for the treatment of chronic pain between September 2012 and August 2015. Preoperatively and postoperatively, patients completed the Numerical Rating Scale (NRS), McGill Pain Questionnaire (MPQ), Pain Catastrophizing Scale (PCS), Oswestry Disability Index (ODI), and Beck's Depression Inventory (BDI). VAS scores were retrospectively analyzed. RESULTS: Fifty-three patients used opioids before SCS implantation. The 33 nonusers had lower mean VAS, NRS, and ODI scores than both opioid groups at 1 yr and improved significantly at 1 yr on the VAS (P < .001), NRS (P < .001), MPQ (P = .002), PCS (P < .001), BDI (P = .04), and ODI (P = .002). After surgery, 41.5% remained opioids and 58.5% reduced/eliminated use. Discontinued (n = 29) or reduced (n = 2) use resulted in VAS, NRS, total MPQ, and ODI score reduction (P < .001, P = .002, P = .002, and P = .009 respectively). At 1 yr, survey scores in opioid users were unchanged. There was no difference between groups in revision or failure rates. CONCLUSION: Sixty-four percent of patients who were using opioids prior to SCS reduced (n = 2) or eliminated opioid use (n = 29) at 1 yr postoperatively. Patients who eliminated opioid use or never used opioids had superior clinical outcomes to those who continued use.

Duloxetine Improves Spinal Cord Stimulation Outcomes for Chronic Pain.

OBJECTIVE: Spinal cord stimulation (SCS) has been shown to be effective in treating chronic pain in patients with varying etiologies. However, the impact of pharmacological treatment on augmenting response to SCS has not been previously studied. METHODS: We enrolled 108 patients who had undergone SCS surgery and documented their pain preoperatively and at 12 months postoperatively using the Numeric Rating Scale (NRS), McGill Pain Questionnaire (MPQ), Beck Depression Inventory (BDI), Oswestry Disability Index (ODI), Pain Catastrophizing Scale (PCS), and Global Impression of Change (GIC). Pain outcomes were compared between patients receiving SCS alone and in addition to duloxetine. RESULTS: At 1-year follow-up, patients receiving duloxetine and SCS (n = 41) had better pain relief in the affective component of MPQ (p < 0.05) than those receiving SCS alone (n = 71). Patients on duloxetine with SCS also were significantly more willing to receive SCS again (p < 0.01). This willingness appeared to be duloxetine dose dependent (p < 0.05). Patients receiving pregabalin or gabapentin with SCS did not have significantly more pain relief than patients receiving SCS alone. CONCLUSION: This study shows the combination therapy to be an effective strategy to provide more holistic pain relief and further improve the quality of life of SCS patients.

Use of a Psychological Evaluation Tool as a Predictor of Spinal Cord Stimulation Outcomes.

INTRODUCTION: Preoperative work-up for spinal cord stimulation (SCS) includes a psychological assessment; however, no one psychological factor has correlated with poor outcomes across studies. We developed a Psychological Evaluation Tool for Spinal Cord Stimulation Candidacy (PETSCSC), which includes all factors in the literature found to correlate with outcomes. In this study, we examine whether PETSCSC correlates with postoperative outcomes. METHODS: Patients undergoing SCS were prospectively enrolled in this study. PETSCSC scores were obtained preoperatively. Numeric rating scale (NRS), global impression of change (GIC), pain catastrophizing scale (PCS), McGill pain questionnaire (MPQ), Oswestry disability index (ODI), and Beck Depression Inventory were assessed preoperatively and postoperatively. Outcomes were correlated with PETSCSC scores. RESULTS: Thirty-four SCS patients had a mean follow-up of 9.88 ± 2.91 months. At latest follow-up, we observed significant improvement in NRS, PCS, MPQ, and ODI. Total PETSCSC score exhibited significant correlation with GIC (p = 0.026, r = 0.380) and improvement in PCS total (p = 0.041, r = 0.351), and MPQ affective (p = 0.002, r = 0.517) scores. The PETSCSC emotive subset significantly correlated with GIC (p = 0.020, r = 0.395). The PETSCSC depression subset significantly correlated with improvement in PCS rumination (p = 0.009, r = 0.439), PCS helplessness (p = 0.021, r = 0.393), PCS total (p = 0.021, r = 0.394), and MPQ affective (p = 0.002, r = 0.501). The PETSCSC therapy subset significantly correlated with improvement in MPQ sensory (p = 0.026, r = -0.381) and MPQ affective (p < 0.001, r = 0.583). DISCUSSION: PETSCSC scores and subscores demonstrate significant correlation with pain outcomes used in assessment of SCS efficacy. Higher PETSCSC scores correlate with greater improvement in GIC, MPQ affective, and PCS scores. Stratification of these patients based on PETSCSC total and subset scores could help with prognostication.

Pain Remission at One-Year Follow-Up With Spinal Cord Stimulation.

OBJECTIVES: Spinal Cord Stimulation (SCS) is an effective treatment for chronic pain. How often pain remission follows SCS has not been evaluated. This is a retrospective analysis of patients who underwent an implantation of spinal cord stimulators for various chronic pain conditions. The objective of the study was to elucidate characteristics and features of patients with pain relief greater than 80% after one year of treatment. METHODS: A total of 86 patients with thoracic SCS and 12-month follow-up data were identified. Patients were divided into a remission group (>80% improvement in Numeric Pain Rating Scale [NRS] pain scale), average responders (20-80% improvement) and a non-responder group (less than 20% improvement). These patient groups were compared via the following outcome measures: NRS, Oswestry Disability Index (ODI), Pain Catastrophizing Scale (PCS), McGill Pain Questionnaire (MPQ), and Insomnia Severity Index (ISI). Correlations with age, body mass index (BMI), tobacco and alcohol usage, patient satisfaction with SCS, disability status, and opioid usage were assessed. RESULTS: Nineteen of 86 patients (22%) were remitters at one year follow-up, including 17 patients who had an NRS = 0 at that time. Upon analyzing the three patient groups (non-responders, average responders, and remitters), remitter patients showed the greatest change over the one-year post-operative period in ODI (F(2) = 8.101, p < 0.01) and PCS (F(2) = 7.607, p < 0.01). Moreover, remission was less likely when the patients were on disability prior to implant (χ2 (2) = 6.469, p < 0.05) and on opioids pre-operatively (χ2 (2) = 17.688, p < 0.01). CONCLUSIONS: Our study demonstrates a remission rate of 22% with SCS at one-year follow with a total of 19.8% of our total patient cohort having an NRS of 0. Greater decreases in PCS and ODI correlate with remission. Further, pre-operative disability and opioid use correlate with lower likelihood of remission.

Prospective Study of the Use of Intraoperative Neuromonitoring in Determining Post-Operative Energy Requirements and Physiologic Midline in Spinal Cord Stimulation.

BACKGROUND: Intraoperative neuromonitoring (IONM) through electromyography (EMG) studies has been shown to be a safe, effective way to determine the laterality of the spinal cord and guide electrode placement during spinal cord stimulation (SCS). However, the use of IONM to predict post-operative energy requirements and midline has not been examined and offers a new avenue to streamline programming and device selection. Further, the impact of cerebrospinal fluid (CSF) thickness on intraoperative and post-operative amplitudes is understood but has not been explicitly characterized. METHODS: A total of 24 patients undergoing SCS implantation for chronic pain had intraoperative EMG studies performed to determine physiologic midline. The intraoperative midline was compared to the midline determined on post-operative day 1 based on paresthesia patterns during programming. For patients who had thoracic leads placed, the amplitudes needed to induce abdominal and extremity lateralization during SCS placement were compared with the intensities needed to induce therapy at post-operative day 1. Additionally, we examined whether CSF thickness, body mass index, diabetes, drug use, and smoking correlated with intraoperative and post-operative amplitudes. RESULTS: Intraoperative EMG was able to predict post-operative paresthesia-based midline in 70.83% of patients. There was a statistically significant relationship between the intraoperative intensity needed to induce extremity lateralization with the post-operative intensity to induce therapy (p = 0.009) as well as the intraoperative intensity needed to stimulate abdominals with the post-operative intensity (p = 0.033). There was also a relationship seen between CSF thickness and the post-operative energy requirements in patients (p = 0.039). DISCUSSION: EMG accurately predicts post-operative energy requirements and midline in SCS patients. While 29.17% of patients did not have a match between their intraoperative and post-operative midlines, EMG testing was still valuable in guiding electrode placement and providing information to predict post-operative intensities. Additionally, CSF thickness correlated with amplitude settings on the first post-operative day.

A Single Center Prospective Observational Study of Outcomes With Tonic Cervical Spinal Cord Stimulation.

BACKGROUND: Spinal cord stimulation (SCS) has been a valuable resource for the treatment of chronic, nonmalignant pain that persists in the face of maximal medical management. A recent study demonstrated efficacy of cervical SCS in a multicenter registry. Here, in our single center study, we are able to delve into patient specifics, explore outcomes with percutaneous vs. paddle implants, and examine impact of patient symptomatology. METHODS: We prospectively collected data on subjects who underwent cervical SCS via numeric rating scale (NRS), McGill Pain Questionnaire, Oswestry Disability Index (ODI), and Beck Depression Inventory. Subjects completed this battery pre-operatively, at six months and at one year. Data were analyzed via repeated measures ANOVA, bivariate correlation analysis, and paired t-tests. RESULTS: In 30 consecutive subjects, 24 had a complete data set. The diagnosis was failed neck surgery syndrome (13%), Complex regional pain syndrome (29%), and neuropathic pain (58%). Compared with baseline, NRS score significantly improved at six months (p = 0.021) and one year (p = 0.047). ODI score also improved at one year (p = 0.009). At both six months and one year, subjects with percutaneous implants reported significantly less disability on ODI (p = 0.016 and 0.034, respectively), as compared with those who received paddle implants. There was no difference in NRS score or any other outcome measure based on type of implant. Diagnosis or region of pain did not correlate with any measure of outcome. DISCUSSION: We demonstrate that neck and arm pain can be improved with cervical SCS at six month and one-year follow-ups. Both percutaneous and paddle implants have benefit. We tend to place percutaneous implants for radicular pain and retrograde C1-2 paddles for axial pain that is ineffectively treated during the trial.

Evolving Concepts in Posterior Subthalamic Area Deep Brain Stimulation for Treatment of Tremor: Surgical Neuroanatomy and Practical Considerations.

BACKGROUND: Although thalamic deep brain stimulation (DBS) has been established as an effective therapy for refractory tremor in Parkinson's disease and essential tremor, reports investigating the efficacy of posterior subthalamic area (PSA) DBS for severe, debilitating tremors continue to emerge. However, questions regarding the optimal anatomical target, surgical approach, programming paradigms and effectiveness compared to other targets remain. OBJECTIVES: In this report, we aimed to review the current literature to assess different stereotactic techniques, anatomical considerations, adverse effects and stimulation settings in PSA DBS. METHODS: A comprehensive literature review was performed searching for articles discussing tremors and PSA stimulation. We performed a quantitative analysis comparing different DBS tremor targets. RESULTS: Tremor improvement is consistently documented in most reports with an average reduction in tremor of 79% depending on the specific tremor syndrome. Tremor benefit in patients with multiple sclerosis (MS) tremor was significantly higher than for other stimulation targets. Transient paresthesias, imbalance, dizziness and dysarthria are the most common side effects with PSA DBS. CONCLUSIONS: PSA DBS is an effective and safe treatment for tremor control and should be considered in patients with refractory tremors with associated cerebellar or dystonic features, proximal tremors and MS tremor.

The Impact of Spinal Cord Stimulation on Sleep Patterns.

BACKGROUND: Studies of chronic pain show sleep disturbances to be a prevalent symptom in 50-88% of patients and studies show improved pain to correspond with improved sleep. The impact of spinal cord stimulation (SCS) on sleep in failed back surgery syndrome, complex regional pain syndrome, and neuropathic pain patients has not been studied prospectively. OBJECTIVES: We prospectively assess the impact of SCS on sleep quality using the Insomnia Severity Index (ISI) and Epworth Sleepiness Scale (ESS). Further we examine the correlations between sleep and pain. METHODS: Patients who underwent permanent SCS implantation completed six validated questionnaires to compare sleep patterns, pain intensity, and quality of life at baseline and six months postoperatively. Results were analyzed via paired samples t-tests and bivariate analysis. RESULTS: Data from 27 patients were collected. We saw a significant decrease in ISI scores (n = 23, t(df)=2.9(22), p = 0.008), and noted a trend in the percentage improvement between ISI and ESS (n = 12, t(df)=2.0(10), p = 0.078). We did not see any significant improvement in ESS. However, improvements in insomnia correlated with pain intensity as measured through visual analog scale score and McGill Pain Questionnaire (R = 0.546, p = 0.007 and R = 0.559, p = 0.006, respectively). DISCUSSION: We demonstrate that insomnia scores on ISI improve with SCS at six-month follow-up. Further, we find that improvements in pain correlate with these ISI improvements.