Neuropathic Pain Medication and Antidepressant Use after Disability Pension in Patients with Spinal Cord Stimulation for Persistent Spinal Pain Syndrome.

Background: Treatment of persistent spinal pain syndrome (PSPS) is challenging. Chronic pain associated with PSPS can lead to an impaired ability to work. Objective: To obtain information on whether receiving a disability pension (DP) affects pain and pain treatments in retiring working-age PSPS patients. Neuropathic pain medication and antidepressant use were considered as an indicator of neuropathic pain. Methods: The study group comprised 129 consecutive PSPS patients with spinal cord stimulation (SCS) devices implanted at Kuopio University Hospital Neurosurgery between January 1, 1996, and December 31, 2014. Purchase data of gabapentinoids, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors from January 1995 to March 2016, as well as the data on working ability, were retrieved from national registries. Results: The data showed that 28 of 129 (21.7%) SCS permanent patients had a DP, and 27 had a sufficient follow-up time (two years before and one year after DP). Most patients (61%) used neuropathic pain medications during the follow-up, while 44% used antidepressants. Most patients (70%, n = 19) retired because of dorsopathies. The dose of gabapentinoids started to increase before the DP; after the DP, the doses started to increase again after the decrease but remained at a lower level. Conclusions: Neuropathic pain medication and antidepressant use suggest that pain continues after the DP-that is, pensioners continue to experience inconvenient chronic pain. Resources for patient care are therefore needed after the DP. However, the DP reduces the dose increase of gabapentinoids; the dose is higher immediately before retirement than at the end of the follow-up.

Disability Pension Did Not Reduce Opioid Use Among Patients With Failed Back Surgery Syndrome Who Were Trialed and Implanted for Spinal Cord Stimulation.

BACKGROUND: Spinal cord stimulation (SCS) is an effective treatment for failed back surgery syndrome (FBSS). In patients with FBSS, opioids have often been initiated, even before SCS is trialed. OBJECTIVE: We studied the effect of retirement on opioid use in patients with chronic pain after failed back surgery. STUDY DESIGN: A retrospective study design. SETTING: The study was conducted at Kuopio University Hospital. METHODS: The study group consisted of all 230 patients with SCS trialed or implanted for FBSS at Kuopio University Hospital Neurosurgery from January 1, 1996 through December 31, 2014. All purchases of prescribed opioids and their daily defined doses, as well as data on working ability, were obtained from the Social Insurance Institution. Patients were divided into 3 groups: SCS trial only, SCS implanted permanently, and SCS implanted but later explanted. We analyzed the differences in opioid use among these groups 2 years before and 2 years after the start of their disability pension (DP). RESULTS: During the follow-up period, a total of 60 patients received a DP. One year before DP, the majority of patients used opioids (n = 43, 72%), and throughout the one-year follow-up after retirement, the number of users increased slightly (n = 46, 77%). In the permanently implanted SCS group, the number of strong opioid users decreased after retirement. Most patients used a moderate dose (0.1-10.5 morphine milligram equivalent/d). Retirement appeared to interrupt dose escalation in all groups, but doses increased further as the follow-up continued. LIMITATIONS: No structured questionnaires were used in this study. Also, many underlying factors contributing to chronic pain were missing. CONCLUSIONS: DP did not reduce the use of opioids in patients with FBSS. Opioid doses were lower and dose escalation less steep with continuous SCS therapy.

Incidence and risk factors of spinal cord stimulation for persistent or recurrent pain after lumbar spine surgery: a population-based study.

PURPOSE: This study aims to elucidate the incidence of and independent risk factors for spinal cord stimulator implantations for patients who underwent lumbar spine surgery. METHODS: The PERFormance, Effectiveness, and Cost of Treatment (PERFECT) episodes database, which was established for selected diseases and procedures in Finland, includes all patients who underwent lumbar spine surgery for degenerative spine conditions or spinal cord stimulation (SCS) in Finland from 1986 to 2018. The data on age, sex, hospital diagnoses, surgical procedures, and causes of death were imported from the Finnish national registers into the PERFECT database. RESULTS: Between 1986 and 2018, 157,824 patients had their first lumbar spine procedure and for 1769 (1.1%) of them, a subsequent SCS procedure was observed during the follow-up. The cumulative incidence of SCS for persistent or recurrent pain after lumbar disk herniation, spinal stenosis, degenerative disk disease, and spondylolysis and spondylolisthesis surgery at 15 years was 1.2%, 1.0%, 2.7%, and 2.6% respectively. At 15 years, the cumulative incidence of SCS for persistent or recurrent pain after lumbar spine surgery after five or more lumbar spinal operations was 11.9%. CONCLUSION: Repeated surgery was the most prominent significant risk factor for SCS for persistent or recurrent pain after lumbar spine surgery. The risk of SCS for persistent or recurrent pain after lumbar spine surgery increases significantly along with the number of lumbar spine procedures. When considering repeated lumbar spine surgery, careful evaluation of treatment options should take place to ensure good patient outcomes.

Long-Term Outcome of Spinal Cord Stimulation in Complex Regional Pain Syndrome.

BACKGROUND: Spinal cord stimulation (SCS) is an effective treatment in chronic neuropathic pain, but its efficacy in complex regional pain syndrome (CRPS) needs to be proven. OBJECTIVE: To study the outcome of SCS in CRPS as measured by trial success, explantation rate, complications, and changes in opioid and neuropathic pain medication use over a 4-yr follow-up. METHODS: We retrospectively reviewed all medical records of 35 consecutive CRPS patients who underwent SCS trials at 2 hospitals during January 1998 to December 2016. The purchase data of opioids and neuropathic pain medication during January 1995 to March 2016 were retrieved from national registries. RESULTS: Based on a 1-wk trial, permanent SCS was implanted in 27 (77%) patients. During the median follow-up of 8 yr, 8 (30%) SCS devices were explanted, of which 7 were because of inefficient pain relief. Complications leading to revision occurred in 17 (63%) patients: 8 electrode migrations or stimulation to the wrong area, 1 deep infection, 9 hardware malfunctions, 2 pulse generator discomforts, and 2 SCS replacements. None of the 6 patients using strong opioids discontinued their use during the 2-yr follow-up. The mean opioid dose increased nonsignificantly both in patients with SCS in permanent use (53 ± 150 morphine milligram equivalents morphine milligram equivalent (MME)/day to 120 ± 240 MME/day) and in patients who had SCS explanted (27 ± 72 MME/day to 57 ± 66 MME/day). CONCLUSION: Despite the fact that CRPS patients were not able to discontinue or reduce their strong opioid or neuropathic pain medication use, 70% continued to use their SCS device during a median 8-yr follow-up.

Gabapentinoids Associated With Lower Explantation Rate in 203 Patients With Spinal Cord Stimulation for Failed Back Surgery Syndrome.

BACKGROUND: Spinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). The effect of neuropathic pain medication use on SCS outcome is poorly understood. OBJECTIVE: To study the effect of gabapentinoid use on SCS outcome measured by trial success, explantation rate and opioid dose reduction during a 2-yr follow-up. METHODS: The study cohort included 203 consecutive FBSS patients who underwent SCS in a single tertiary center during January 1997 to March 2014. Purchase data of gabapentinoids, opioids, tricyclic antidepressants, serotonin and noradrenaline reuptake inhibitors, and benzodiazepines during January 1995 to March 2016 were retrieved from national registries. RESULTS: In multivariate Cox regression analysis, patients using gabapentinoids had significantly fewer explantations during the 2-yr follow-up (hazard ratio [HR] 0.2, 95% CI 0.04-0.81, P = .03). In contrast, patients with opioid use of >40 morphine milligram equivalent before implantation had significantly more explantations (HR 6.7, 95% CI 2.5-18, P < .01). In bivariate logistic regression analysis adjusted for patient specific factors, year of SCS implantation, use of neuropathic pain medication, opioids, and benzodiazepines, patients using gabapentinoids significantly more often discontinued opioids or reduced their dose by more than 50% during the 2-yr follow-up (odds ratio 5.7, 95% CI 1.4-23, P = .015). CONCLUSION: The use of gabapentinoids was associated with a significantly lower spinal cord stimulator explantation rate and a higher chance of opioid discontinuation or >50% dose reduction. This indicates that patients with SCS could benefit from concomitant use of gabapentinoids. Prospective randomized trials are warranted to verify this hypothesis.

Higher Preimplantation Opioid Doses Associated With Long-Term Spinal Cord Stimulation Failure in 211 Patients With Failed Back Surgery Syndrome.

OBJECTIVE: Spinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period. MATERIALS AND METHODS: The study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries. RESULTS: Higher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001). CONCLUSIONS: Higher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.

Benzodiazepine Use Is Associated With Poorer Spinal Cord Stimulation Outcome in 373 Neuropathic Pain Patients.

OBJECTIVES: The aim of the study is to investigate whether benzodiazepine use differs between patients with favorable and unfavorable spinal cord stimulation (SCS) treatment outcome. We hypothesize that the patients with unfavorable SCS outcome would exhibit a higher level of benzodiazepine use. MATERIALS AND METHODS: Using a case-control study setting, we examined benzodiazepine use in SCS patients and in matched population controls as a potential risk factor poor SCS outcome. A total of 373 consecutive SCS patients treated in Kuopio University Hospital between 1997 and 2014 and their 1117 matched population controls were followed until patient death or the end of March 2016. RESULTS: Benzodiazepines were used during the 24-month period before or after SCS implantation by 42.3% of the SCS patients who had the device explanted, 39.5% who had an unsuccessful trial stimulation, 28.0% who still had the device at the end of the follow-up period, and 8.0% of the controls. Diazepam use before SCS increased the odds for explanting of SCS by 2.4-fold (95% Cl: 1.0-5.4). Starting clonazepam use after SCS was associated with a 5.2-fold (95% CI: 1.5-18.9) increase in the odds of unsuccessful trial stimulation. CONCLUSION: The benzodiazepine use in patients with poor SCS outcome illustrates the role of anxiety in SCS outcomes and the need for multidisciplinary treatment of pain.

High Level of Childhood Trauma Predicts a Poor Response to Spinal Cord Stimulation in Chronic Neuropathic Pain.

BACKGROUND: Spinal cord stimulation (SCS) relieves pain by delivering doses of electric current to the dorsal column of the spinal cord and has been found to be most effective in the treatment of neuropathic pain. Psychological distress is a significant risk factor for the development of chronic pain and has been found to affect the outcome of SCS. Childhood trauma is a risk factor for chronic pain, but has not previously been studied in SCS patients. OBJECTIVES: The objective of this prospective registry-based study was to investigate the prevalence of 5 domains of childhood trauma (emotional neglect, emotional abuse, physical neglect, physical abuse, and sexual abuse) and their relationship with the outcome of spinal cord stimulation on patients suffering from treatment-resistant chronic pain. METHODS: SCS patients treated at Kuopio University Hospital between 1/1/2015 and 12/31/2016 were sent a survey in the mail, the Trauma and Distress Scale, assessing childhood trauma (n = 43). Neuropathic pain, disability, anxiety, and depression were measured in the patients pre-surgery and at 6 and 12 months post-surgery. The patients who provided their name on the questionnaire (n = 22) and had suffered from 3 or more domains of trauma were grouped as the high-trauma group (n = 13) and the rest as the low-trauma group (n = 9). RESULTS: The questionnaire was completed by 40 patients (93%). At least 1 domain of trauma was experienced by 35 (88%) patients, and at least 2 by 24 (60%). The low-trauma group displayed a statistically significant decrease in the mean PainDETECT score from 21.5 before SCS to 16.5 at 12 months post-surgery (Wilk's lambda = 0.297, F(2,9) = 10.6, P = 0.004), contrary to the high- trauma group (Wilk's lambda = 0.904, F(2,6) = 0.3, P = 0.739). LIMITATIONS: Only 22 of the 40 patients provided their name on the questionnaire, which decreased the sample size on follow-up. CONCLUSION: This was the first study to investigate childhood trauma in SCS patients. Patients who had experienced high amounts of childhood trauma did not experience any relief from neuropathic pain 12 months' post-SCS, contrary to the low-trauma group. Childhood trauma might be a factor worth screening in the preoperative evaluation and aftercare of SCS candidates. KEY WORDS: Spinal cord stimulation, the Trauma and Distress Scale, chronic pain, childhood trauma, childhood abuse, childhood neglect, chronic back pain, back pain, psychological distress, neuropathic pain.

Effect of Spinal Cord Stimulation on Early Disability Pension in 198 Failed Back Surgery Syndrome Patients: Case-Control Study.

BACKGROUND: Spinal cord stimulation (SCS) has proven to be a cost-effective treatment for failed back surgery syndrome (FBSS). However, the effect on patients' working capability remains unclear. OBJECTIVE: To evaluate the impact of SCS on working capability and to identify the factors behind permanent disability in FBSS patients. METHODS: The study group consisted of 198 working-age patients with SCS trialed or implanted for FBSS in a single center between 1996 and 2014. For each patient, 3 living controls, matched by age, gender, and birthplace, were otherwise randomly selected by the Population Register Center. The data on working ability were obtained from the Social Insurance Institution. Patients were divided into 3 groups: SCS trial only, SCS implanted permanently, and SCS implanted but later explanted. RESULTS: A rehabilitation subsidy was given to 68 patients and 8 controls for a mean of 5.2 (95% confidence interval [CI] 2.4-8.2) and 0.2 (95% CI 0.05-0.6) days per month (P < .05). At the end of follow-up, 16 (37%), 13 (33%), 25 (22%), and 27 (5%) subjects were on disability pension (DP) in the SCS trial, SCS explanted, SCS permanent, and control groups. Patients in the SCS trial-only group were significantly more often on DP than were patients with permanent SCS (odds ratio 2.6; 95% CI 1.2-5.9; P = .02). CONCLUSION: Permanent SCS usage was associated with reduced sick leave and DP. Prospective study will be required to assess possible predictive value.

Long-Term Outcome of Spinal Cord Stimulation in Failed Back Surgery Syndrome: 20 Years of Experience With 224 Consecutive Patients.

BACKGROUND: Failed back surgery syndrome (FBSS) is a challenging condition that lacks a curative treatment. In selected patients, spinal cord stimulation (SCS) has provided a satisfactory outcome. OBJECTIVE: To evaluate the long-term outcome of SCS in FBSS, as measured by (1) the explantation rate, (2) complications, and (3) patient satisfaction with the global perceived effect (GPE). METHODS: We studied 224 consecutive FBSS patients who underwent an SCS trial with surgically implanted leads at our hospital between January 1996 and December 2014. The patients' satisfaction with the GPE of treatment was measured through a postal questionnaire at the end of follow-up. RESULTS: Based on a 1-wk trial, permanent SCS was implanted in 175 (78%) patients. Out of these patients, 153 (87%) reported satisfactory outcomes after 2 mo. During the mean follow-up of 6 yr, 34 (19%) of SCS devices were permanently explanted due to inadequate pain relief, and 11 (6%) were explanted for other reasons.Electrode revision due to inadequate pain relief was done for 22 patients. In total, 26 complications were reported due to: 7 deep infections, 11 hardware malfunctions, 1 subcutaneous hematoma, 4 instances of discomfort due to the pulse generator, and 3 electrode migrations.One hundred thirty patients (74%) continued with SCS until the end of follow-up. Of them, 61 (47%) returned the questionnaire, and 42 (69%) reported substantially improved or better GPE. CONCLUSION: SCS can provide a good outcome in the treatment of FBSS. Patient selection could be further improved by developing novel predictive biomarkers.