Burst spinal cord stimulation can attenuate pain and its affective components in chronic pain patients with high psychological distress: results from the prospective, international TRIUMPH study.

BACKGROUND CONTEXT: Psychological characteristics such as catastrophizing and depression have been shown to negatively impact outcome prognosis after spinal interventions. PURPOSE: To evaluate whether high psychological distress, defined as clinically elevated levels of catastrophizing and depression, is associated with poorer outcomes after spinal cord stimulation utilizing a passive recharge burst stimulation design. This proprietary waveform may uniquely attenuate the emotional aspects of chronic pain given its affects on the medial pain pathway projecting to the dorsal anterior cingulate cortex and anterior insula. STUDY DESIGN/SETTINGS: Data were extracted from the prospective, multi-center, single-arm, international TRIUMPH study. The purpose of TRIUMPH was to assess long-term (2 years) safety and effectiveness of spinal cord stimulation for chronic pain in the trunk and/or limbs using a passive recharge enabled burst spinal cord stimulation (B-SCS) system. PATIENT SAMPLE: Two subsets of study patients were identified; those with (n=31) and those without (n=54) high psychological distress. OUTCOME MEASURES: Psychological and functional outcomes as well as pain intensity and impact of pain on life were administered at baseline and all follow intervals. Additionally, patient satisfaction and patient global impression of change were assessed at all follow-up intervals. METHODS: Psychological distress (PD) was defined as a baseline score of ≥ 30 on the Pain Catastrophizing Scale (PCS) and ≥ 10 on the Patient Health Questionnaire Depression scale (PHQ-9). Nondistressed (ND) patients had scores below these thresholds on both scales. All patients were implanted with a B-SCS system and completed data collection for the 24-month follow-up visit. This study was funded by Abbott. JMH is a consultant for Abbott and has received <$20,000 in lifetime consulting fees from Abbott. SMF is a consultant for Abbott and has received >$50,000 in lifetime consulting fees from Abbott. BB is an Abbott employee. RAC is a former Abbott employee. JJY is a consultant for Abbott and has received <$2,500 in lifetime consulting fees from Abbott. RESULTS: Of the 128 participants with 24-month data, 31 (24%) and 54 (35%) met the criteria for PD and ND, respectively. Baseline measures indicated a more severe chronic pain profile and worse quality of life in the PD group. Two years after implant, 71% were no longer clinically catastrophizing and 58% were no longer clinically depressed. Notably, more than half of the PD patients on antidepressants discontinued or decreased their medication. Health-related quality of life was 82% higher in the PD group at 24 months, reaching levels similar to the ND group. Psychological distress did not impact outcomes after SCS therapy; composite multi-responder rates were similar in the 2 groups throughout the follow-up period. Patient reported pain relief (58% PD vs. 61% ND) was equivalent in each group. In both groups, 81% were satisfied or very satisfied with the pain relief provided. CONCLUSIONS: Our results showed that B-SCS appears to be as effective in a chronic pain population with high psychological distress as in those without distress. This may be due to the unique mechanism of action with the stimulation design involving the emotional-affective medial pain pathway in the brain.

Passive Recharge Burst Spinal Cord Stimulation Provides Sustainable Improvements in Pain and Psychosocial Function: 2-year Results From the TRIUMPH Study.

STUDY DESIGN: Prospective, international, multicenter, single-arm, post-market study. OBJECTIVE: The aim of this study was to assess long-term safety and effectiveness of spinal cord stimulation using a passive recharge burst stimulation design for chronic intractable pain in the trunk and/or limbs. Herein we present 24-month outcomes from the TRIUMPH study (NCT03082261). SUMMARY OF BACKGROUND DATA: Passive recharge burst spinal cord stimulation (B-SCS) uniquely mimics neuronal burst firing patterns in the nervous system and has been shown to modulate the affective and attentional components of pain processing. METHODS: After a successful trial period, subjects received a permanent SCS implant and returned for follow-up at 6, 12, 18, and 24 months. RESULTS: Significant improvements in physical, mental, and emotional functioning observed after 6 months of treatment were maintained at 2 years. Pain catastrophizing scale (PCS) scores dropped below the population norm. Health-related quality of life on EQ-5D improved across all domains and the mean index score was within one standard deviation of norm. Pain reduction (on NRS) was statistically significant (P < 0.001) at all timepoints. Patient reported pain relief, a stated percentage of improvement in pain, was consistent at all timepoints at 60%. Patients reported significant improvements across all measures including activity levels and impact of pain on daily life. At 24 months, 84% of subjects were satisfied and 90% would recommend the procedure. Subjects decreased their chronic pain medication intake for all categories; 38% reduced psychotropic and muscle relaxants, 46% reduced analgesic, anti-convulsant and NSAIDs, and 48% reduced opioid medication. Adverse events occurred at low rates without unanticipated events. CONCLUSION: Early positive results with B-SCS were maintained long term. Evidence across multiple assessment tools show that B-SCS can alleviate pain intensity, psychological distress, and improve physical function and health-related quality of life.Level of Evidence: 3.

Improved Psychosocial and Functional Outcomes and Reduced Opioid Usage Following Burst Spinal Cord Stimulation.

OBJECTIVE: Burst spinal cord stimulation (B-SCS) has been shown to reduce neuronal firing in the anterior cingulate cortex through selective modulation of the medial pain pathway tract. This pain pathway communicates the affective component of pain processing. The purpose of this study was to assess the effect of B-SCS on psychosocial functioning and its influence on pain and quality of life. MATERIALS AND METHODS: Eligible patients with chronic, intractable pain of the trunk, and/or lower limbs were enrolled. After a successful trial period, subjects received a permanent implant and returned for follow-up at 6- and 12-months. RESULTS: In total, 269 patients were enrolled at 22 centers. Trial success rate was 90%. Significant improvements in pain, physical, mental, and emotional functioning were observed from baseline to the 6- and 12-month follow-up (p < 0.001). Overall, patients had improved quality of life, became more active, and the negative impact of pain on daily life was decreasing. At one year, 81% of subjects were satisfied or very satisfied with their therapy. Subjects showing significant improvements on mental health outcomes reported enhanced pain relief and quality of life scores compared with subjects with continued impaired mental health at follow-up. At one year, 89% of subjects who were taking opioids at baseline decreased or stayed at the same level of opioid use; 19% stopped taking any opioids. No unanticipated adverse events have been reported. CONCLUSIONS: One-year outcomes after B-SCS show improvements across all evaluated psychological measures with the largest impact observed on catastrophizing and depression (the affective component of pain processing). These pain-related beliefs and behaviors, and not pain intensity, have been shown to put patients at greatest risk of a poor prognosis and quality of life.

Anatomic Lead Placement Without Paresthesia Mapping Provides Effective and Predictable Therapy During the Trial Evaluation Period: Results From the Prospective, Multicenter, Randomized, DELIVERY Study.

OBJECTIVE: The purpose of this study was to compare the trial success rate between anatomic lead placement (AP) and paresthesia-mapped (PM) lead placement techniques for spinal cord stimulation (SCS) using a nonlinear burst stimulation pattern. MATERIALS AND METHODS: Eligible patients with back and/or leg pain with a Numeric Rating Scale (NRS) score of ≥6 who had not undergone previous SCS were enrolled in the study. A total of 270 patients were randomized in a 1:1 ratio to each treatment arm. In the AP group, one lead tip was placed at the mid-body of T8, and the other at the superior endplate of T9. In the PM group, physicians confirmed coverage of the patient's primary pain location. Trial success was a composite of the following: ≥50% patient-reported pain relief at the end of the minimum three-day trial period, physician's recommendation, and patient's interest in a permanent implant. RESULTS: Trial success for AP vs. PM groups was equivalent to 84.4% and 82.3%, respectively. Physicians who performed both techniques preferred AP technique (70% vs. 30%). Procedure times for placement of two leads were 31% shorter in the AP group (p < 0.0001). Decrease in the mean NRS pain score was similar between groups (53.2%, AP group; 53.8%, PM group, p = 0.79). Trial success for patients who went on to an extended trial with tonic stimulation was 50% (5/10) vs. 79% (11/14) for AP group and PM group, respectively (p = 0.2). A total of 13 adverse events were observed (4.5%), most commonly lead migrations and pain around implant site, with no difference between groups. CONCLUSIONS: When using a nonlinear burst stimulation pattern, anatomic or PM lead placement technique may be used. Nonresponders to subthreshold stimulation had a higher conversion rate when a PM technique was used. AP resulted in shorter procedure times with a similar safety profile and was strongly preferred by trialing physicians.

Sensory nerve stimulation causes an immediate improvement in motor function of persons with multiple sclerosis: A pilot study.

BACKGROUND: Multiple sclerosis (MS) symptoms reported in the first year of the disease include sensory impairment, fatigue, reduced mobility, and declines in hand function. The progressive reduction in motor function experienced by persons living with MS is invariably preceded by changes in sensory processing, which are strongly associated with the declines in both walking performance and manual dexterity. AIMS: To assess the influence of concurrent sensory stimulation using augmented transcutaneous electrical nerve stimulation (aTENS) applied to leg and hand muscles on clinical tests of motor function in individuals whose mobility was compromised by MS. METHODS: Thirteen persons with MS (52 ±â€¯8 years; 6 women) and 12 age- and sex-matched healthy adults (52 ±â€¯9 years) met the inclusion criteria. Participants visited the lab on two occasions with one week between visits. Each visit involved the participant performing four tests of motor function and completing two health-related questionnaires (PDDS and MSWS-12). The tests assessed walking performance (6-min test and 25-ft test), dynamic balance (chair-rise tes, and manual dexterity (grooved pegboard test). aTENS was applied through pads attached to the limbs over the tibialis anterior and rectus femoris muscles of the affected leg, and over the median nerve and the thenar eminence of the dominant hand. The pads were attached during both visits, but the current was only applied during the second visit. The stimulation comprised continuous asymmetrical biphasic pulses (0.2 ms) at a rate of 50 Hz and an intensity that elicited slight muscle contractions. RESULTS: At baseline and during both treatment sessions, the performance on all four tests of motor function was worse for the MS group than the Control group. The MS group experienced significant improvements in all outcomes during the aTENS session with medium-to-large effect sizes. PDDS ratings improved (from 2.8 ±â€¯1.3 to 2.0 ±â€¯1.5; effect size d = -0.70) and the MSWS-12 scores declined (from 36 ±â€¯11 to 28 ±â€¯12; effect size d = -1.52). The concurrent application of aTENS enabled the MS group to walk further during the 6-min test (from 397 ±â€¯174 m to 415 ±â€¯172 m; effect size d = 0.81), to complete the 25-ft test in less time (6.7 ±â€¯3.0 s to 6.3 ±â€¯2.9 s; effect size d = -0.76), to increase the counts in the chair-rise test (from 11.2 ±â€¯3.8 to 13.6 ±â€¯4.8; effect size d = 1.52), and to perform the grooved pegboard test more quickly (from 110 ±â€¯43 s to 99 ±â€¯37 s; effect size d = -0.98). The only significant effect for the Control group was a significant increase in the 6-min walk distance (from 725 ±â€¯79 to 740 ±â€¯82 m; effect size d = 0.87). CONCLUSIONS: Stimulation of sensory fibers with aTENS evoked clinically significant improvements in four tests of motor function and the self-reported level of walking limitations in persons who were moderately disabled by MS. Moreover, the improvements in function elicited by the concurrent application of aTENS were immediate.

Effectiveness and Safety of Dorsal Root Ganglion Stimulation for the Treatment of Chronic Pain: A Pooled Analysis.

INTRODUCTION: Since it became available in the mid-2010s, dorsal root ganglion (DRG) stimulation has become part of the armamentarium to treat chronic pain. To date, one randomized controlled trial, and several studies of moderate sample size and various etiologies have been published on this topic. We conducted a pooled analysis to investigate the generalizability of individual studies and to identify differences in outcome between chronic pain etiologic subgroups and/or pain location. MATERIALS AND METHODS: One prospective, randomized comparative trial and six prospective, single-arm, observational studies were identified that met pre-defined acceptance criteria. Pain scores and patient-reported outcome (PRO) measures were weighted by study sample sizes and pooled. Safety data are reported in aggregate form. RESULTS: Our analysis included 217 patients with a permanent implant at 12-month follow-up. Analysis of pooled data showed an overall weighted mean pain score of 3.4, with 63% of patients reporting ≥50% pain relief. Effectiveness sub-analyses in CRPS-I, causalgia, and back pain resulted in a mean reduction in pain intensity of 4.9, 4.6, and 3.9 points, respectively. Our pooled analysis showed a pain score for primary affected region ranging from 1.7 (groin) to 3.0 (buttocks) and responder rates of 80% for foot and groin, 75% for leg, and 70% for back. A substantial improvement in all PROs was observed at 12 months. The most commonly reported procedural or device complications were pain at the IPG pocket site, lead fracture, lead migration, and infection. CONCLUSIONS: DRG stimulation is an effective and safe therapy for various etiologies of chronic pain.

Self-massage prior to stretching improves flexibility in young and middle-aged adults.

We examined the influence of stretching alone (SS) or combined with self-massage (SM) on maximal ankle dorsiflexion angle, maximal voluntary contraction (MVC) torque and calf muscle activity, and subcutaneous tissue thickness in 15 young (25 ± 3 years) and 15 middle-aged (45 ± 5 years) adults. Participants performed two sessions of calf muscle stretches (3x 30-s stretches, 30-s rest): stretch after a 60-s control condition (SS) and stretch after 60 s of self-massage with therapy balls (SM). Evaluations were performed before and 5 min after the intervention. Linear mixed effects model revealed no main effect for age on ROM or MVC and significant main effects for treatment and time. Change in ankle angle was greater after SM: SS = 3.1 ± 2°, SM = 6.2 ± 3.3° (Hedges' g = 0.98, p < 0.001). Similar results were observed for MVC torque: SS = -4 ± 16%, SM = 12 ± 16% (Hedges' g = 0.97, p = 0.0001). Changes in MVC torque and absolute EMG amplitude were correlated, but subcutaneous tissue thickness was not altered by treatment. The gains in ROM were more pronounced in less flexible middle-aged adults, underscoring the need to include flexibility exercises in their training.

Individuals with sacroiliac joint dysfunction display asymmetrical gait and a depressed synergy between muscles providing sacroiliac joint force closure when walking.

Walking is often compromised in individuals with low back and hip disorders, such as sacroiliac joint dysfunction (SIJD). The disorder involves reduced coactivation of the gluteus maximus and contralateral latissimus dorsi, which together provide joint stability during walking. The purpose of our study was to compare the kinematics and contributions of selected muscles to identified synergies during walking between healthy individuals and those with SIJD. Six women with unilateral SIJD and six age-matched healthy controls walked on a force-measuring treadmill at 1 m/s while we recorded kinematics and the activity of 16 muscles with surface EMG. Non-negative matrix factorization was used to identify patterns of EMG activity (muscle synergies). Individuals with SIJD exhibited less hip extension and lower peak vertical ground reaction forces on the affected side than the unaffected side. In contrast to controls, the SIJD group also displayed a depressed muscle synergy between gluteus maximus on the affected side and the contralateral latissimus dorsi. The results indicate that individuals with SIJD exhibited both reduced activation of gluteus maximus during a loading synergy present in walking and greater asymmetry between legs when walking compared with age-matched controls.

Patients with sacroiliac joint dysfunction exhibit altered movement strategies when performing a sit-to-stand task.

OF BACKGROUND DATA: The ability to rise from a chair is a basic functional task that is frequently compromised in individuals diagnosed with orthopedic disorders in the low back and hip. There is no published literature that describes how this task is altered by sacroiliac joint dysfunction (SIJD). PURPOSE: The objective of this study was to compare lower extremity biomechanics and the onset of muscle activity when rising from a chair in subjects with SIJD and in healthy persons. STUDY DESIGN: Six women with unilateral SIJD and six age-matched healthy controls performed a sit-to-stand task while we measured kinematics, kinetics, and muscle activity. MATERIALS AND METHODS: Subjects stood up at a preferred speed from a seated position on an armless and backless adjustable stool. We measured kinematics with a 10-camera motion capture system, ground reaction forces for each leg with force plates, and muscle activity with surface electromyography. Joint angles and torques were calculated using inverse dynamics. Leg-loading rate was quantified as the average slope of vertical ground reaction (VGRF) force during the 500-millisecond interval preceding maximal knee extension. RESULTS: Between-leg differences in loading rates and peak VGRFs were significantly greater for the SIJD group than for the control group. Maximal hip angles were significantly less for the SIJD group (p=.001). Peak hip moment in the SIJD group was significantly greater in the unaffected leg (0.75±0.22 N⋅m/kg) than in the affected leg (0.47±0.29 N⋅m/kg, p=.005). There were no between-leg or between-group differences for peak knee or ankle moments. The onset of activity in the latissimus dorsi muscle on the affected side was delayed and the erector spinae muscles were activated earlier in the SIJD group than in the control group. CONCLUSIONS: Subjects with SIJD have a greater VGRF on the unaffected leg, generate a greater peak hip moment in the unaffected leg, use a smaller range of motion at the hip joint of the affected leg, and delay the onset of a key muscle on the affected side when rising from a seated position.

Manipulation of sensory input can improve stretching outcomes.

The primary purpose of our study was to assess the influence of modulating sensory input with either transcutaneous electrical nerve stimulation (TENS) or self-massage with therapy balls on the maximal range of motion (ROM) about the ankle joint when stretching the calf muscles. We also investigated the influence of these two conditions on the force capacity and force control of plantar flexor muscles. Twenty healthy adults (25 ± 3 yr) performed three sessions of ankle plantar flexor stretching (three stretches of 30 s each): stretching alone (SS), stretching with concurrent TENS (TENS), and stretching after self-massage using therapy balls (SM). TENS was applied for 60 s prior to and during each stretch, and SM was performed for 60 s prior to each of the three stretches. Maximal voluntary contraction (MVC) torque and force steadiness at 20% MVC were recorded before and at 15 min after the final stretch. Ankle dorsiflexion ROM was assessed before, after, and at 5, 10, and 15 min after the last stretch. The increase in ROM was greater after SM (24%) than after SS (13%) and TENS (9%; p < .001). Maximal discomfort level (0-10 VAS) during stretching was similar for all conditions. MVC torque increased after SM only (p < .001, Cohen's D = 1.5): SM, 16%; SS, -1%; TENS, -3%. Force steadiness did not change. The sensory fibres that contribute to stretch tolerance were engaged by self-massage but not by TENS, resulting in greater increases in flexibility and MVC torque after self-massage.

Implant survivorship analysis after minimally invasive sacroiliac joint fusion using the iFuse Implant System(®).

INTRODUCTION: Surgical revision rate is a key outcome with all permanent implants. The iFuse Implant System(®) is a permanent implant used to perform minimally invasive sacroiliac joint fusion. The purpose of this study is to determine the surgical revision rate after sacroiliac joint fusion surgery with this system. METHODS: Using two internal sources of information, revision surgeries were identified and linked to index surgeries. The likelihood of revision surgery was calculated using the Kaplan-Meier life table approach. Predictors of revision were explored. RESULTS: Four-year survivorship free from implant revision was 96.46%. Revision rate did not differ by sex and was lower for age >65. In all, 24% of revisions occurred within the first 30 days after surgery; 63.5% occurred within year 1. Implant survivorship has improved annually since the device was introduced in 2009. CONCLUSION: The survivorship rate with this implant is high and improving; the rate is somewhat higher than total hip replacement but lower than that of lumbar spine procedures.

Spine device clinical trials: design and sponsorship.

BACKGROUND CONTEXT: Multicenter prospective randomized clinical trials represent the best evidence to support the safety and effectiveness of medical devices. Industry sponsorship of multicenter clinical trials is purported to lead to bias. PURPOSE: To determine what proportion of spine device-related trials are industry-sponsored and the effect of industry sponsorship on trial design. STUDY DESIGN: Analysis of data from a publicly available clinical trials database. METHODS: Clinical trials of spine devices registered on ClinicalTrials.gov, a publicly accessible trial database, were evaluated in terms of design, number and location of study centers, and sample size. The relationship between trial design characteristics and study sponsorship was evaluated using logistic regression and general linear models. RESULTS: One thousand six hundred thrity-eight studies were retrieved from ClinicalTrials.gov using the search term "spine." Of the 367 trials that focused on spine surgery, 200 (54.5%) specifically studied devices for spine surgery and 167 (45.5%) focused on other issues related to spine surgery. Compared with nondevice trials, device trials were far more likely to be sponsored by the industry (74% vs. 22.2%, odds ratio (OR) 9.9 [95% confidence interval 6.1-16.3]). Industry-sponsored device trials were more likely multicenter (80% vs. 29%, OR 9.8 [4.8-21.1]) and had approximately four times as many participating study centers (p<.0001) and larger sample sizes. There were very few US-based multicenter randomized trials of spine devices not sponsored by the industry. CONCLUSIONS: Most device-related spine research is industry-sponsored. Multicenter trials are more likely to be industry-sponsored. These findings suggest that previously published studies showing larger effect sizes in industry-sponsored vs. nonindustry-sponsored studies may be biased as a result of failure to take into account the marked differences in design and purpose.

Minimally invasive sacroiliac joint fusion: one-year outcomes in 18 patients.

BACKGROUND: Sacroiliac joint (SI) pain is an often-overlooked cause of low back pain due, in part, to lack of specific findings on radiographs and symptoms mimicking other back-related disorders. We report our experience with minimally invasive (MIS) SI joint arthrodesis using a series of triangular, titanium plasma spray (TPS) coated implants in patients refractory to conservative care. METHODS: We report outcomes from 18 patients with 12 months of postoperative follow-up.Demographics, complications, and clinical outcomes using visual analog scale (VAS) for pain, Oswestry Disability Index (ODI) for back function and SF-12 for quality of life were collected preoperatively and at 3, 6 and 12 months post-operatively. RESULTS: Mean age was 64 years and 67% of patients were female. There were no intraoperative complications and one explant at three months for malposition.All patient-reported outcomes showed both clinically and statistically significant improvement at 12 months (p < 0.001 for each of the following): VAS improved by 6.6 points, ODI scores improved by -37.5 points. One year SF-12 physical and mental component (PCS, MCS) scores approximated population normal scores for both physical and mental functioning. Patient satisfaction with outcomes was high at 95%; 89% said would have the same surgery again. CONCLUSIONS: MIS SI joint fusion using a series of triangular porous TPS coated titanium implants is a safe and effective procedure for patients with SI joint disorders who have failed conservative care.