Do implantable devices improve mood? Comparisons of chronic pain patients with or without an implantable device

The Predicted Outcome of Spinal Cord Stimulation in Patients With a Psychopathological Disorder and Persistent Spinal Pain Syndrome Type 2: A Systematic Review From 2009 to 2021

OBJECTIVES

Psychologic screening is often included as a mandatory component of evaluation of the impact of psychopathology disorders on the predicted outcome of spinal cord stimulation (SCS) for patients with chronic pain due to persistent spinal pain syndrome type 2 (PSPS type 2). The conclusion of such screenings can influence the decision to offer SCS therapy to a patient. However, evidence on the impact of psychopathology on SCS outcomes is still scarce.

MATERIALS AND METHODS

To address this knowledge gap, we systematically reviewed the literature from 2009 to 2021 to explore the correlation between the presence of a psychopathological disorder and the predicted outcome of SCS in patients with PSPS type 2. The literature search was conducted using various online data bases with "failed back surgery syndrome," "psychopathology," and "spinal cord stimulation" used as essential keywords. The identified studies were organized in a Rayyan AI data base, and the quality was analyzed with the Critical Appraisal Skills Program tool.

RESULTS

Our search generated the identification of 468 original articles, of which two prospective and four retrospective studies met our inclusion criteria. These studies reported pain relief, a reduction of symptoms of anxiety and depression, and an improvement in rumination on the Pain Catastrophizing Scale in patients with PSPS type 2 after SCS therapy. The studies also found contradictory outcomes measured using the Oswestry Disability Index, and in terms of the impact of psychopathological disorder on the clinical outcome and revision rate of the SCS system.

CONCLUSION

In this systematic review, we found no convincing evidence that the presence of a psychopathological disorder affects the predicted outcome of SCS therapy in patients with PSPS type 2.

Spinal Cord Stimulation to Treat Low Back Pain in Patients With and Without Previous Spine Surgery

OBJECTIVES

Little is known about the effects of spinal cord stimulation (SCS) on chronic low back pain (CLBP) patients with no history of previous spine surgery. Using our prospectively collected database, we evaluate improvements in patients with and without previous spine surgery one-year post SCS implantation.

MATERIALS AND METHODS

Subjects completed outcome metrics pre-operatively and one-year post-implantation including Numeric Rating Scale (NRS), McGill Pain Questionnaire (MPQ), Oswestry Disability Index (ODI), Beck's Depression Inventory (BDI), and Pain Catastrophizing Scale (PCS).

RESULTS

We enrolled 134 patients; 82 patients had previous spine surgery and 52 patients did not. At one-year post-SCS implantation, patients with previous spine surgery showed improvements in worst pain experienced, least pain experienced, average pain experienced, pain felt currently, MPQ, MPQ sensory, MPQ affective, PCS, PCS helplessness, PCS rumination, PCS magnification, ODI, and BDI scores (p < 0.001, p = 0.005, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.03, p = 0.01, p = 0.02, p < 0.001, p = 0.05, p < 0.001, p = 0.017, respectively). Likewise, patients without previous spine surgery showed improvements in worst pain experienced, least pain experienced, average pain experienced, pain felt currently, MPQ, MPQ sensory, PCS, PCS helplessness, PCS rumination, PCS magnification, ODI, and BDI scores (p < 0.001, p = 0.005, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.008, p < 0.001, p < 0.001, respectively). Patients without previous spine surgery showed greater improvements for average pain PCS helplessness (p = 0.01).

CONCLUSIONS

Patients with and without previous spine surgery showed similar improvements in pain intensity, pain quality, feelings of rumination and magnification, functional disability, and depression severity. SCS can improve CLBP regardless of whether patients have had previous spine surgery.

Quantitative sensory phenotyping in chronic neuropathic pain patients treated with unilateral L4-dorsal root ganglion stimulation

Background

In a previous study, we reported that selective dorsal root ganglion stimulation (DRG_STIM) at DRG level L4 promoted a favorable outcome for complex regional pain syndrome (CRPS) patients along with DRG_STIM-related changes of inflammatory biomarkers in blood and saliva. The impact on somatosensation is largely unknown. Herein, we assessed the quantitative sensory profile to quantify L4-DRG_STIM effects in CRPS patients.

Methods

Twelve refractory CRPS patients (4 female; 8 male; mean age 69 ± 9 years) received standardized quantitative sensory testing (QST) protocol at baseline and after 3 months of unilateral L4-DRG_STIM assessing nociceptive and non-nociceptive thermal and mechanical sensitivity of the knee affected by CRPS and the contralateral non-painful knee area.

Results

At baseline, CRPS subjects showed significantly increased thresholds for warmth, tactile and vibration detection (WDT, MDT and VDT) and exaggerated pain summation (WUR). After 3 months of unilateral L4-DRG_STIM all pain parameters exhibited trends towards normalization of sensitivity accumulating to a significant overall normalization for pain sensitivity (effect size: 0.91, p < 0.01), while with the one exception of WDT all non-nociceptive QST parameters remained unchanged. Overall change of non-nociceptive detection was negligible (effect size: 0.25, p > 0.40). Notably, reduction of pain summation (WUR) correlated significantly with pain reduction after 3 months of L4-DRG_STIM.

Conclusions

Selective L4-DRG_STIM lowered ongoing pain in CRPS patients and evoked significant normalization in the pain domain of the somatosensory profile. Thermoreception and mechanoreception remained unchanged. However, larger randomized, sham-controlled trials are highly warranted to shed more light on effects and mechanisms of dorsal root ganglion stimulation on quantitative sensory characteristics.

The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267).

https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267

Experiences From the Patient Perspective on Spinal Cord Stimulation for Failed Back Surgery Syndrome: A Qualitatively Driven Mixed Method Analysis

INTRODUCTION

When neither pharmacological therapies nor alternative interventions provide sufficient pain relief, spinal cord stimulation (SCS) can be used to treat Failed Back Surgery Syndrome (FBSS). Although it seems reasonable that quality of life (QoL)- and psychosocial-related factors contribute to the outcome of SCS since pain is a multidimensional experience, few qualitative studies have explored the expectations of SCS and experiences on SCS to treat FBSS from the patient perspective.

OBJECTIVES

The aim of this study was to qualitatively and quantitatively map the FBSS patients' experiences with SCS and the effects of SCS on low back pain caused by FBSS.

MATERIALS AND METHODS

A qualitative study with in-depth semi-structured interviews, assisted by the Brief Pain Inventory (BPI)-questionnaire.

RESULTS

Seven themes regarding patients' experiences, subdivided into 15 categories, were identified, including an understudied theme within this field of research, Spiritual Well-Being. "Acceptance" and "coping" emerged as pre-eminent motifs throughout these themes. Moreover, the realization of patients' expectations were variable throughout the presented themes. According to the BPI Questionnaire, four out of 13 patients (31%) had significant pain relief (≥50%). Seven out of 13 (54%) reported a ≥50% increase regarding enjoyment of life.

CONCLUSION

Multiple QoL- and psychosocial-related themes are related to SCS-outcomes. In order to improve SCS-outcomes for both short- and long-term, these themes should be implemented as a multidimensional approach, both prior to implantation as during follow-up.

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.

Are Multidimensional Pain Inventory Coping Strategy Profiles Associated with Long-Term Spinal Cord Stimulation Effectiveness?

Introduction

It is acknowledged that the way patients cope with pain may influence treatment outcome. In particular, psychological factors are deemed important when considering patients for suitability for spinal cord stimulation (SCS).

Objective

The aim of the study is to observe how pre-implantation psychological characteristics impact the effectiveness of SCS for chronic pain.

Methods

The analysis comprised data from 137 patients who underwent an SCS implant. Screening evaluation included a coping strategies profile (Multidimensional Pain Inventory) and psychiatric disorders (Mini-International Neuropsychiatric Interview). Based on SCS implant outcome collected during follow-up visits, patients were divided into three groups: subjects with long-term pain relief (long-term group), subjects who failed the SCS treatment and decided to explant trial device (trial explanter group [TE]), and those who chose a permanent device (permanent explanter group [PE]).

Results

Results showed that most of the patients who failed with the SCS (TE and PE groups) demonstrated a dysfunctional coping profile and showed a higher presence of psychiatric disorders, which significantly influenced the experience and perception of pain.

Conclusions

The findings of this study support the value of a multidisciplinary screening. Addressing psychological issues before SCS implantation can reduce the failure rate of SCS.

Spinal Cord Stimulation Provides Pain Relief with Improved Psychosocial Function: Results from EMP3OWER

OBJECTIVE

The EMP³OWER™ study evaluated spinal cord stimulation (SCS) safety and efficacy and the associated changes in psychosocial and functional outcomes.

METHODS

Upon informed consent and IRB approval, 620 eligible subjects were enrolled prior to SCS trial evaluation and were assessed at baseline, 3, 6 and 12 months post-implant. Patient-reported pain relief (PRP), numerical rating scale (NRS), satisfaction, quality of life (QOL), and pain disability index (PDI) were assessed at all follow-up visits while the pain catastrophizing scale (PCS), short form-36 (SF-36), short form-McGill pain questionnaire version 2 (SF-MPQ-2), and the state-trait anxiety inventory (STAI) were assessed at the 6- and 12-month follow-up visits. Device and/or procedure-related adverse events were also recorded and reported. Subjects reporting a PRP ≥ 50% were considered responders. Repeated measures analysis of variance (RMANOVA) examined the changes across time for all continuous measures.

RESULTS

A total of 401 (71%) subjects received a permanent implant. Mean (±SD) patient-reported pain relief was 59.3% (±26.2), 59.2% (±28.9), and 58.2% (±32.0) at 3, 6, and 12 months, respectively. A majority of enrolled subjects were responders at 3 (75.5%), 6 (74.7%), and 12 months (69.7%). RMANOVA revealed a statistically significant change for NRS, PCS, PDI, SF-36, SF-MPQ-2, and STAI scores. At 3 months, the majority of subjects (85.7%) were either very satisfied or satisfied with their device, with similar results at 6 and 12 months. At 3 months, the majority of subjects (73.3%) reported greatly improved or improved QOL with similar results at 6 and 12 months.

CONCLUSIONS

Spinal cord stimulation provided pain relief and significant improvement of patient psychological and functional outcome measures.

Presurgical Psychological Assessments as Correlates of Effectiveness of Spinal Cord Stimulation for Chronic Pain Reduction

BACKGROUND

Spinal Cord Stimulator (SCS) is a surgically implanted device for patients with certain types of chronic pain. While some studies show the value of psychological screening of potential SCS candidates, no consensus exists. This single-site study analyzed the association of SCS success with psychological assessments (e.g., Millon Behavioral Medicine Diagnostic), beliefs regarding SCS efficacy, self-reported pain and quality of life (QOL) among patients approved for SCS.

METHODS

Potential SCS candidates (N = 200) were contacted 3-7 years after initial psychological and medical clearance for SCS; 59 consented to a structured telephone interview. Thirty-four of the 59 had received a SCS; 25 had not received a SCS. Of the 34 that had received a SCS, 22 were approved by routine psychological evaluation while 12 went through in-depth psychological testing.

RESULTS

The majority of respondents (62%) reported effective pain reduction, and 64% of SCS recipients reported improved QOL. Younger patients reported higher pre-implantation pain scores, and participants with higher levels of pain preimplantation were more likely say they would undergo the procedure again. Finally, persons reporting preoperative alcohol problems were more likely to report lower levels of post-SCS pain.

CONCLUSION

Predictors of pain relief and QOL following SCS may depend on expectations of the device and on individuals' interpretation of pain or psychosocial health.

Psychological screening/phenotyping as predictors for spinal cord stimulation

Spinal cord stimulation (SCS) is becoming a widely used treatment for a number of pain conditions and is frequently considered as a pain management option when conservative or less invasive techniques have proven to be ineffective. Potential indications for SCS include complex regional pain syndrome (CRPS), postherpetic neuralgia, traumatic nerve injury, failed back surgery syndrome, refractory angina pectoris, peripheral vascular disease, neuropathic pain, and visceral pain (Guttman et al. Pain Pract. 9:308-11, 2009). While research on SCS is in its infancy, it is clear that substantial variation exists in the degree of benefit obtained from SCS, and the procedure does not come without risks; thus focused patient selection is becoming very important. Psychological characteristics play an important role in shaping individual differences in the pain experience and may influence responses to SCS, as well as a variety of other pain treatments (Doleys Neurosurg Focus 21:E1, 2006). In addition to psychological assessment, quantitative sensory testing (QST) procedures offer another valuable resource in forecasting who may benefit most from SCS and may also shed light on mechanisms underlying the individual characteristics promoting the effectiveness of such procedures (Eisenberg et al. Pain Pract. 6:161-165, 2006). Here, we present a brief overview of recent studies examining these factors in their relationship with SCS outcomes.

Qualitative exploration of psychological factors associated with spinal cord stimulation outcome

BACKGROUND AND AIM

Spinal cord stimulation (SCS) is a last resort treatment for chronic pain consisting of an implantable pulse generator connected to leads placed in the epidural space of the spinal cord. Effective in reducing chronic pain, however, efficacy has been found to decrease over time. Psychological factors affecting outcome of SCS have been investigated through quantitative methods, but these have failed to provide confident predictors. We aimed to investigate via a qualitative approach, the experience of SCS following 1 year of therapy.

METHODS

Thirteen chronic non-cancer pain participants were interviewed. All participants had been trialled with SCS. The majority had gone on to full implantation with varying degrees of pain relief. Thematic analysis was employed to analyse the data from the interviews.

RESULTS

Interviews resulted in findings that previous quantitative studies had failed to uncover. Two emergent core themes surfaced: 'coping with pain' and 'SCS treatment'. The effect of emotion upon coping was recurrent. Participants divided the SCS experience into information provision, independence and unexpected experiences.

CONCLUSION

The findings provide context for the patients' experience of SCS. This research suggests that improved preparation prior to SCS including information provision, CBT and contact with expert patients may be of value.