Long-term outcomes following intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: 5-year treatment arm results from a prospective randomized double-blind sham-controlled multi-center study.

BACKGROUND: Damaged or degenerated vertebral endplates are a significant cause of vertebrogenic chronic low back pain (CLBP). Modic changes are one objective MRI biomarker for these patients. Prior data from the treatment arm of a sham-controlled, RCT showed maintenance of clinical improvements at 2 years following ablation of the basivertebral nerve (BVN). This study reports 5-year clinical outcomes. METHODS: In total, 117 US patients were treated successfully with BVN ablation. Patient-reported outcomes of ODI, VAS, postablation treatments, and patient satisfaction were collected at a minimum of 5-years following BVN ablation. Primary outcome was mean change in ODI. Comparisons between the postablation and baseline values were made using an analysis of covariance with alpha 0.05. RESULTS: Of the 117 US treated patients 100 (85%) were available for review with a mean follow-up of 6.4 years (5.4-7.8 years). Mean ODI score improved from 42.81 to 16.86 at 5-year follow-up, a reduction of 25.95 points (p < 0.001). Mean reduction in VAS pain score was 4.38 points (baseline of 6.74, p < 0.001). In total, 66% of patients reported a > 50% reduction in pain, 47% reported a > 75% reduction in pain, and 34% of patients reported complete pain resolution. Composite responder rate using thresholds of ≥ 15-point ODI and ≥ 2-point VAS for function and pain at 5 years was 75%. CONCLUSION: CLBP patients treated with BVN ablation exhibit sustained clinical improvements in function and pain with high responder rates at a mean of 6.4 years following treatment. BVN ablation is a durable, minimally invasive treatment for vertebrogenic CLBP.

Therapy Habituation at 12 Months: Spinal Cord Stimulation Versus Dorsal Root Ganglion Stimulation for Complex Regional Pain Syndrome Type I and II.

The ACCURATE randomized, controlled trial compared outcomes of dorsal root ganglion (DRG) stimulation versus tonic spinal cord stimulation (SCS) in 152 subjects with chronic lower extremity pain due to complex regional pain syndrome (CRPS) type I or II. This ACCURATE substudy was designed to evaluate whether therapy habituation occurs with DRG stimulation as compared to SCS through 12-months. A modified intention-to-treat analysis was performed to assess percentage pain relief (PPR) and responder rates at follow-up visits (end-of-trial, 1, 3, 6, 9, 12-months postpermanent implant) for all subjects that completed trial stimulation (DRG:N = 73, SCS:N = 72). For both groups, mean PPR was significantly greater at end-of-trial (DRG = 82.2%, SCS =0 77.0%) than all other follow-ups. Following permanent DRG system implantation, none of the time points were significantly different from one another in PPR (range = 69.3-73.9%). For the SCS group, PPR at 9-months (58.3%) and 12-months (57.9%) was significantly less than at 1-month (66.9%). The responder rate also decreased for the SCS group from 1-month (68.1%) to 12-months (61.1%). After stratifying by diagnosis, it was found that only the CRPS-I population had diminishing pain relief with SCS. DRG stimulation resulted in more stable pain relief through 12-months, while tonic SCS demonstrated therapy habituation at 9- and 12-months. Trial Registration: The ACCURATE study was registered at ClinicalTrials.gov with Identifier NCT01923285. PERSPECTIVE: This article reports on an ACCURATE substudy, which found that long-term therapy habituation occurred at 12-months with SCS, but not DRG stimulation, in patients with CRPS. The underlying mechanisms of action for these results remain unclear, although several lines of inquiry are proposed.

Paresthesia-Free Dorsal Root Ganglion Stimulation: An ACCURATE Study Sub-Analysis.

INTRODUCTION: ACCURATE, a randomized controlled trial comparing dorsal root ganglion (DRG) stimulation to spinal cord stimulation, showed that DRG stimulation is a safe and effective therapy in individuals with lower extremity chronic pain due to complex regional pain syndrome (CRPS) type I or II. Investigators noted that DRG stimulation programming could be adjusted to minimize, or eliminate, the feeling of paresthesia while maintaining adequate pain relief. The present study explores treatment outcomes for DRG subjects who were paresthesia-free vs. those who experienced the sensation of paresthesia, as well as the factors that predicted paresthesia-free analgesia. METHODS: A retrospective analysis of therapy outcomes was conducted for 61 subjects in the ACCURATE study who received a permanent DRG neurostimulator. Outcomes of subjects who were paresthesia-free were compared to those who experienced paresthesia-present therapy at 1, 3, 6, 9, and 12-month follow-ups. Predictor variables for the presence or absence of paresthesias with DRG stimulation were also explored. RESULTS: The percentage of subjects with paresthesia-free pain relief increased from 16.4% at 1-month to 38.3% at 12-months. Paresthesia-free subjects generally had similar or better outcomes for pain severity, pain interference, quality of life, and mood state as subjects with paresthesia-present stimulation. Factors that increased the odds of a subject feeling paresthesia were higher stimulation amplitudes and frequencies, number of implanted leads, and younger age. CONCLUSIONS: Some DRG subjects achieved effective paresthesia-free analgesia in the ACCURATE trial. This supports the observation that paresthesia is not synonymous with pain relief or required for optimal analgesia with DRG stimulation.

Intraosseous Basivertebral Nerve Ablation for the Treatment of Chronic Low Back Pain: 2-Year Results From a Prospective Randomized Double-Blind Sham-Controlled Multicenter Study.

BACKGROUND: The purpose of the present study is to report the 2-year clinical outcomes for chronic low back pain (CLBP) patients treated with radiofrequency (RF) ablation of the basivertebral nerve (BVN) in a randomized controlled trial that previously reported 1-year follow up. METHODS: A total of 147 patients were treated with RF ablation of the BVN in a randomized controlled trial designed to demonstrate safety and efficacy as part of a Food and Drug Administration-Investigational Device Exemption trial. Evaluations, including patient self-assessments, physical and neurological examinations, and safety assessments, were performed at 2 and 6 weeks, and 3, 6, 12, 18, and 24 months postoperatively. Participants randomized to the sham control arm were allowed to cross to RF ablation at 12 months. Due to a high rate of crossover, RF ablation treated participants acted as their own control in a comparison to baseline for the 24-month outcomes. RESULTS: Clinical improvements in the Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and the Medical Outcomes Trust Short-Form Health Survey Physical Component Summary were statistically significant compared to baseline at all follow-up time points through 2 years. The mean percent improvements in ODI and VAS compared to baseline at 2 years were 53.7 and 52.9%, respectively. Responder rates for ODI and VAS were also maintained through 2 years with patients showing clinically meaningful improvements in both: ODI ≥ 10-point improvement in 76.4% of patients and ODI ≥ 20-point improvement in 57.5%; VAS ≥ 1.5 cm improvement in 70.2% of patients. CONCLUSIONS: Patients treated with RF ablation of the BVN for CLBP exhibited sustained clinical benefits in ODI and VAS and maintained high responder rates at 2 years following treatment. Basivertebral nerve ablation appears to be a durable, minimally invasive treatment for the relief of CLBP.

Comparison of Paresthesia Coverage of Patient's Pain: Dorsal Root Ganglion vs. Spinal Cord Stimulation. An ACCURATE Study Sub-Analysis.

OBJECTIVES: This was a sub-analysis of the ACCURATE clinical trial that evaluated the accuracy and necessity of targeting paresthesia coverage of painful areas with dorsal root ganglion (DRG) stimulation vs. tonic spinal cord stimulation (SCS). MATERIALS AND METHODS: On diagrams of the torso and lower limbs, subjects marked where they felt pain at baseline and paresthesias at three months postimplant. Seventy-five subjects (41 DRG and 34 SCS) with diagrams of sufficient quality were scanned, digitized, and included in this analysis. Subject completed diagrams were digitized and superimposed with a grid of 1398 squares. Quantification of the percentage of bodily areas affected by pain and stimulation induced paresthesias was performed. RESULTS: The percent of painful areas covered by paresthesia was significantly lower for DRG subjects than for SCS subjects (13% vs. 28% of the painful regions, p < 0.05), possibly because significantly more DRG subjects felt no paresthesia during stimulation when compared to SCS subjects (13/41 DRG vs. 3/34 SCS) (p < 0.05). The amount of paresthesia produced outside the painful areas (unrequired paresthesia) was significantly lower in DRG subjects than that of SCS subjects. On average, the percent of unrequired paresthesia was only 20% of the subjects' total painful body surface area in the DRG group compared to 210% in the SCS group (p < 0.01). CONCLUSIONS: The results of this ACCURATE study sub-analysis show that DRG stimulation produces paresthesias, on average, that are less frequent, less intense, with a smaller footprint on the body and less dependent on positional changes.

Dorsal root ganglion stimulation yielded higher treatment success rate for complex regional pain syndrome and causalgia at 3 and 12 months: a randomized comparative trial.

Animal and human studies indicate that electrical stimulation of dorsal root ganglion (DRG) neurons may modulate neuropathic pain signals. ACCURATE, a pivotal, prospective, multicenter, randomized comparative effectiveness trial, was conducted in 152 subjects diagnosed with complex regional pain syndrome or causalgia in the lower extremities. Subjects received neurostimulation of the DRG or dorsal column (spinal cord stimulation, SCS). The primary end point was a composite of safety and efficacy at 3 months, and subjects were assessed through 12 months for long-term outcomes and adverse events. The predefined primary composite end point of treatment success was met for subjects with a permanent implant who reported 50% or greater decrease in visual analog scale score from preimplant baseline and who did not report any stimulation-related neurological deficits. No subjects reported stimulation-related neurological deficits. The percentage of subjects receiving ≥50% pain relief and treatment success was greater in the DRG arm (81.2%) than in the SCS arm (55.7%, P < 0.001) at 3 months. Device-related and serious adverse events were not different between the 2 groups. Dorsal root ganglion stimulation also demonstrated greater improvements in quality of life and psychological disposition. Finally, subjects using DRG stimulation reported less postural variation in paresthesia (P < 0.001) and reduced extraneous stimulation in nonpainful areas (P = 0.014), indicating DRG stimulation provided more targeted therapy to painful parts of the lower extremities. As the largest prospective, randomized comparative effectiveness trial to date, the results show that DRG stimulation provided a higher rate of treatment success with less postural variation in paresthesia intensity compared to SCS.

Pain quality of life as measured by utilities.

OBJECTIVE: Utilities are values of health-related quality of life (HRQoL) based on patient preference for a health status. The purpose of this study was to compare indirect measures to a directly elicited utility. DESIGN: Cross-sectional study. SETTING AND PATIENTS: Emory Spine Center and the Emory Center for Chronic Pain at Crawford Long Hospital. Patients at least 18 years of age with chronic pain, defined as pain that persists beyond the normal time of healing, usually beyond 6 months. MEASURES: Chronic pain subjects completed a paper-based, self-administered time trade-off (TTO) survey, EQ-5D survey, and a face-to-face (FTF) TTO interview. Current pain severity was graded using the Numeric Rating Scale-11, subsequently stratified into no (0), mild (1-3), moderate (4-6), and severe (7-10) pain. RESULTS: Paired t test comparing FTF TTO and proxy utility measures stratified by severity revealed FTF TTO utility values significantly higher than EQ-5D utility values for all pain severities (overall mean difference 0.18, standard deviation [SD] 0.30, P < 0.001; Pearson's correlation 0.34, P < 0.0001); FTF TTO utility values were lower than paper TTO utility values, reaching statistical significance for mild and moderate pain (overall mean difference 0.09, SD 0.29, P = 0.0006; Pearson's correlation 0.38, P < 0.0001). CONCLUSIONS: This study demonstrates that the EQ-5D overestimates, whereas the paper version of TTO underestimates, the impact of pain on HRQoL compared with the directly elicited FTF TTO utility. Our findings provide preliminary evidence that utilities vary by method, and directly elicited utility values differ from indirectly elicited measures.

A prospective randomized FDA-IDE trial comparing Cortoss with PMMA for vertebroplasty: a comparative effectiveness research study with 24-month follow-up.

STUDY DESIGN: Randomized, controlled, prospective (AAOS therapeutic level I) trial conducted under Food and Drug Administration Investigational Device Exemption hypothesized noninferiority of a novel bioactive composite material to polymethylmethacrylate (PMMA). OBJECTIVE: To determine the safety and efficacy of a new, nonresorbable bioactive composite (Cortoss) compared with PMMA, the standard treatment of vertebral compression fractures (VCFs). SUMMARY OF BACKGROUND DATA: Vertebroplasty with PMMA, the widely adopted treatment for VCFs nonresponsive to conservative care, provides effective, immediate pain relief, but the material has received criticism for its properties. A new bioactive composite material designed specifically for vertebroplasty showed promising results in animals and nonrandomized clinical studies and was subsequently compared with PMMA in a randomized study. This study represents the first prospective study evaluating vertebroplasty comparing PMMA with another material with 24-month follow-up. METHODS: Using 2:1 randomization, vertebroplasty was performed with Cortoss on 162 patients and PMMA on 94 patients. Inclusion criteria were painful osteoporotic VCFs with a visual analogue scale pain score of at least 50 mm on a 100-mm scale and at least 30% disability as measured by the Oswestry Disability Index. Evaluations at pretreatment, treatment day, and 7 posttreatment intervals out to 24 months included pain, disability, neurological status, adverse events, quality of life, patient satisfaction, analgesic use, and independently reviewed radiographs. RESULTS: Noninferiority of Cortoss relative to PMMA was observed, with Cortoss-treated patients experiencing significant pain relief at 3 months (P = 0.0395) and better maintenance or improvement in function at 24 months (P = 0.0299). Incidence of serious device-related adverse events was 4.3% in both groups; none were life threatening. CONCLUSION: Vertebroplasty using either Cortoss or PMMA provides effective, immediate, and lasting pain relief and prevents further loss of function. Both materials performed comparably at most time points; Cortoss demonstrated better results for pain reduction at 3 months and for function at 24 months.

Adverse events of conscious sedation in ambulatory spine procedures.

BACKGROUND CONTEXT: Interventional spine procedures are commonly performed in the ambulatory surgical setting, often using conscious sedation. The rate of adverse events with conscious sedation has not been previously assessed in the interventional spine procedure setting. PURPOSE: The goal of this study was to determine the rate of adverse events when using conscious sedation in the ambulatory interventional spine setting. STUDY DESIGN: A retrospective cohort chart review analysis was performed on all interventional spine procedures performed during one calendar year at a university-affiliated ambulatory surgery center by six nonanesthesia-trained spine interventionalists. PATIENT SAMPLE: Of the 3,342 procedures performed that year, 2,494 charts (74.6%) were available for review. OUTCOME MEASURES: Adverse events were documented immediately after the procedure and at a maximum 3-day follow-up phone call. METHODS: The rate and type of adverse events were analyzed and compared between those who received conscious sedation with local anesthesia and those who received local anesthesia alone. RESULTS: Of the 2,494 cases reviewed, 1,228 spine procedures were performed with local anesthesia and conscious sedation, and 1,266 procedures were performed with local anesthesia alone. Of these cases, 66 immediate adverse events (5.12%) were documented in the conscious sedation group, and 61 immediate adverse events (4.82%) were documented in the local anesthesia alone group. At maximum 3-day follow-up, 670 patients of the conscious sedation group were available for contact, and 699 patients were available from the local anesthesia group. Thirty-two adverse events (4.77%) were noted in the conscious sedation group, and 28 adverse events (4.00%) were noted in the local anesthesia group. Comparison of these rates found no significant statistical difference. However, patients in the local anesthesia group had a significantly higher rate of postoperative hypertension. Adverse events reported both immediately and at follow-up were determined to be mild, with no serious adverse events reported. CONCLUSION: The findings of this study suggest that mild to moderate conscious sedation in interventional spine procedures is associated with low rates of adverse events when established protocols are followed.

The impact of pruritus on quality of life: the skin equivalent of pain.

OBJECTIVE: To compare the impact of chronic pruritus and chronic pain on quality of life (QoL) using directly elicited health utility scores. DESIGN: Cross-sectional study. SETTING: Convenience sample of patients attending the Emory Dermatology Clinic, Emory Spine Center, and Emory Center for Pain Management, Atlanta, Georgia. PARTICIPANTS: Adult men and women (aged ≥ 18 years) experiencing chronic pain or pruritus for 6 weeks or more. MAIN OUTCOME MEASURES: The mean utility score of patients with chronic pruritus was compared with that of patients with chronic pain. A regression analysis was performed to determine the impact of the primary predictor variable-symptom type-on the primary outcome variable-mean utility score (a metric representing the impact on QoL). RESULTS: The study included 73 patients with chronic pruritus and 138 patients with chronic pain. The mean (SD) utility among patients with pruritus was 0.87 (0.27) compared with 0.77 (0.31) for patients with pain (P < .01). After symptom severity, duration, and demographic factors were controlled for, only symptom severity (0.03 [P < .05]) and single marital status (-0.12 [P = .02]), but not symptom type (P = .43), remained significant predictors of the mean symptom utility score. CONCLUSIONS: Chronic pruritus has a substantial impact on QoL, one that may be comparable to that of pain. The severity of symptoms and the use of support networks are the main factors that determine the degree to which patients are affected by their symptoms. Addressing support networks in addition to developing new therapies may improve the QoL of itchy patients.

Interlaminar versus transforaminal epidural steroid injections for the treatment of symptomatic lumbar spinal stenosis.

BACKGROUND: Lumbar spinal stenosis is a common condition that causes axial low back pain, radicular pain, and neurogenic claudication. Epidural steroid injections are commonly used for the treatment of radicular symptoms and neurogenic claudication associated with symptomatic lumbar spinal stenosis. No prior study has evaluated whether transforaminal or interlaminar epidural steroid injections produce better clinical outcomes. DESIGN: Retrospective case control study. METHODS: For each technique, 19 patients were retrospectively identified who received their first fluoroscopically guided epidural steroid injection for radicular and neurogenic claudication symptoms caused by lumbar spinal stenosis over a 12-month interval. All patients had corresponding MRI findings and had failed previous non-invasive therapies. Outcomes included the visual analog scale (VAS, 0-10 scale) immediately before the injection, immediately after the injection, and upon follow up at 4-6 weeks. Surgery rates and number of repeat injections over a 3 year period were also analyzed. The patient groups were matched for age and level of stenosis on MRI. RESULTS: There was no statistically significant difference between the two groups in pre injection to follow up VAS scores (P=0.919). The difference between number of repeat injections between the interlaminar and transforaminal groups was not statistically significant (0.91-mean 2.47 and 2.58, respectively). Both the interlaminar and transforaminal groups experienced statistically significant improvement in VAS scores from before the injection to after the injection, and on follow up. Low numbers underwent surgery (11% in the interlaminar group vs 15% in the transforaminal group, not significant, P=0.63). CONCLUSIONS: In the current study, neither transforaminal nor interlaminar steroid injections resulted in superior short term pain improvement or fewer long term surgical interventions or repeat injections when compared with each other.

Single level lumbar disc herniations resulting in radicular pain: pain and functional outcomes after treatment with targeted disc decompression.

STUDY DESIGN: Single-arm prospective clinical trial. OBJECTIVE: To determine the treatment effect and MRI changes of targeted disc decompression using an intradiscal catheter for focal heating of symptomatic lumbar disc protrusions resulting in radicular pain. SUMMARY OF BACKGROUND DATA: Percutaneous methods for treatment of lumbar disc herniations are potentially attractive alternatives to open surgical discetomies. The effects of a newly designed, percutaneous electrothermal intradiscal catheter were evaluated. METHODS: Twenty-two subjects with MRI confirmed, single-level contained lumbar disc protrusions, a minimum of 8 weeks of radicular pain (average 63 weeks) and failed nonsurgical treatment were invited. Nineteen patients underwent the decompression procedure. Follow-up was performed by physical exam and pain severity visual analog scale (VAS), SF-36 bodily pain (BP)/physical functioning (PF) scores for 12 months post-procedure. MRIs were obtained prior to treatment and at 3 months post-procedure. RESULTS: Eighty-four percent of treated patients were available for follow-up at 12 months. The mean reduction in leg pain VAS scores was 2.6 points (40.6%, 95% CI 1.0-4.1). The mean reduction in back pain VAS scores was 2.4 points (44.4%, 95% CI 0.8-4.0). SF-36 BP scores improved 28.8 points (95% CI 17.5-40.0) and SF-36 PF scores improved 25.4 points (95% CI 13.0-37.7) on average. Effect sizes were small for VAS scores and moderate for SF-36 scores. Fifty-four percent of disc herniations were improved or resolved on MRI. No device-related or intraoperative complications were observed. CONCLUSIONS: Targeted disc decompression provided moderate improvement in leg pain and function in the majority of patients with chronic radicular pain.

Radiculopathy and the herniated lumbar disk: controversies regarding pathophysiology and management.

Lumbar disk herniation is one of the most common problems encountered in orthopaedic practice. Despite the frequency of its occurrence, however, much about lumbar disk herniation is poorly understood. It is important to review the basic and clinical science underlying the pathophysiology and treatment, surgical and nonsurgical, of this disorder.

Interlaminar versus transforaminal epidural injections for the treatment of symptomatic lumbar intervertebral disc herniations.

BACKGROUND: Epidural steroid injections are commonly used for the treatment of radicular symptoms associated with symptomatic lumbar intervertebral disc herniations. Transforaminal epidural injections are believed to produce better clinical outcomes than interlaminar epidural injections. OBJECTIVE: To determine a difference in short-term pain improvement and longterm surgical rates between interlaminar and transforaminal injection techniques. DESIGN: Case Control Study. METHODS: For each technique, 20 patients were retrospectively identified who received their first fluoroscopically guided epidural steroid injection for radicular symptoms caused by a lumbar intravertebral disc herniation over an 18 months interval. All patients had corresponding MRI findings and failed previous non-invasive therapies. The Verbal Numerical Rating Scale (VNRS, 0-10 scale) before the treatment, within one hour after the treatment and upon follow-up (average 17.1 days) were analyzed, along with the need for repeat injections and surgical interventions over a 1-year follow-up interval. The patient groups were matched for symptom duration, MRI findings and pre-injection VNRS scores. RESULTS: In the transforaminal group, there was a statistically significant improvement in the VNRS scores from before the injection (VNRS mean 5.9) to immediately after the injection (VNRS mean 2.9, p<0.01), and upon follow-up (VNRS mean 3.2, p<0.01, mean 18.7 days). Nine patients (45%) required 1 or 2 repeated injections, 2 patients (10%) underwent surgery. In the interlaminar group, there was a statistically significant improvement in the VNRS scores from before the injection (VNRS mean 7.3) to immediately after the injection (VNRS mean 3.1, p<0.01), and upon follow-up (VNRS mean 5.9, p<0.01, mean 15.6 days). Eight patients (40%) required 1 or 2 repeated injection, 5 patients (25%) underwent surgery. Fourteen patients (70%) had an improvement of 2 points or more on the VNRS scale in the transforaminal group, compared to 9 (45%) in the interlaminar group. CONCLUSIONS: In the current study, transforaminal epidural steroid injections for the treatment of symptomatic lumbar disc herniation resulted in better short-term pain improvement and fewer long-term surgical interventions than interlaminar epidural steroid injection.

Physical function measurements in neck pain.

The literature on physical and functional measurements for the cervical spine is more limited than for the lumbar spine. Most of the studies so far have dealt with the methods for range-of-motion measurements in the cervical spine. These studies indicate that newer computer-guided, three-dimensional measurements systems may provide more precise and reliable data than inclinometer-based techniques and visual estimation methods. The research available also shows a correlation between training and strength improvement in the cervical spine. In addition to physical measurements, several tests have been developed to measure pain level, psychologic factors, disability from neck pain, and generic health, which can assist the clinician in choosing the most appropriate treatment for patients with neck pain. Furthermore, functional measurement systems, such as FCEs, have been developed to describe the functional limitations that a patient may have as a result of a spinal injury. Except for the range-of-motion measurement methods, much more research is required to determine which measurement systems provide the optimal balance between reliability and validity and pragmatic considerations such as time and expense.

Outcome research in patients with chronic low back pain.

Outcome research in chronic low-back pain is entering a new phase. In the past several years, several outcome measures have been evaluated for their psychometric properties, and databases for patients with low-back pain exist for some of them. A set of recommended and standardized outcome measures and questionnaires is now available for the different outcome domains. The use of computerized versions of these questionnaires will allow simplified data collection and analyses, which will not only help to formulate a more uniform design of research trials, but can be useful for clinicians interested in documenting multi-dimensional outcomes in their patient population.