Matthew Smuck

Plasma disc decompression compared with fluoroscopy-guided transforaminal epidural steroid injections for symptomatic contained lumbar disc herniation: a prospective, randomized, controlled trial

OBJECT Patients with radiculopathy, with or without back pain, often do not respond to conservative care and may be considered for epidural steroid injection therapy or a disc decompression procedure. Plasma disc decompression (PDD) using the Coblation SpineWand device is a percutaneous, minimally invasive interventional procedure. The purpose of this study was to evaluate clinical outcomes with PDD as compared with standard care using fluoroscopy-guided transforaminal epidural steroid injection (TFESI) over the course of 2 years. METHODS This was a multicenter randomized controlled clinical study. Ninety patients (18-66 years old) who had sciatica (visual analog scale score > or = 50) associated with a single-level lumbar contained disc herniation were enrolled. In all cases, their condition was refractory to initial conservative care and 1 epidural steroid injection had failed. Participants were randomly assigned to receive either PDD (46 patients) or TFESI (44 patients, up to 2 injections). RESULTS The patients in the PDD Group had significantly greater reduction in leg pain scores and significantly improved Oswestry Disability Index and 36-Item Short Form Health Survey ([SF-36], physical function, bodily pain, social function, and physical components summary) scores than those in the TFESI Group. During the 2-year follow-up, 25 (56%) of the patients in the PDD Group and 11 (28%) of those in the TFESI Group remained free from having a secondary procedure following the study procedure (log-rank p = 0.02). A significantly higher percentage of patients in the PDD Group showed minimum clinically important change in scores for leg and back pain and SF-36 scores that exceeded literature-based minimum clinically important changes. Procedure-related adverse events, including injection site pain, increased leg or back pain, weakness, and lightheadedness, were observed in 5 patients in the PDD Group (7 events) and 7 in the TFESI Group (14 events). CONCLUSIONS In study patients who had radicular pain associated with a contained lumbar disc herniation, those patients treated with PDD had significantly reduced pain and better quality of life scores than those treated using repeated TFESI. In addition, significantly more PDD patients than TFESI patients avoided having to undergo a secondary procedure during the 2-year study follow-up.

A proposed set of metrics for standardized outcome reporting in the management of low back pain

Background and purpose — Outcome measurement has been shown to improve performance in several fields of healthcare. This understanding has driven a growing interest in value-based healthcare, where value is defined as outcomes achieved per money spent. While low back pain (LBP) constitutes an enormous burden of disease, no universal set of metrics has yet been accepted to measure and compare outcomes. Here, we aim to define such a set. Patients and methods — An international group of 22 specialists in several disciplines of spine care was assembled to review literature and select LBP outcome metrics through a 6-round modified Delphi process. The scope of the outcome set was degenerative lumbar conditions. Results — Patient-reported metrics include numerical pain scales, lumbar-related function using the Oswestry disability index, health-related quality of life using the EQ-5D-3L questionnaire, and questions assessing work status and analgesic use. Specific common and serious complications are included. Recommended follow-up intervals include 6, 12, and 24 months after initiating treatment, with optional follow-up at 3 months and 5 years. Metrics for risk stratification are selected based on pre-existing tools. Interpretation — The outcome measures recommended here are structured around specific etiologies of LBP, span a patient’s entire cycle of care, and allow for risk adjustment. Thus, when implemented, this set can be expected to facilitate meaningful comparisons and ultimately provide a continuous feedback loop, enabling ongoing improvements in quality of care. Much work lies ahead in implementation, revision, and validation of this set, but it is an essential first step toward establishing a community of LBP providers focused on maximizing the value of the care we deliver.

Accuracy of intermittent fluoroscopy to detect intravascular injection during transforaminal epidural injections

Study Design. Prospective validity study. Objective. To determine how accurately intermittent fluoroscopy detects inadvertent intravascular injection during transforaminal epidurals. Summary of Background Data. Serious morbidity caused by transforaminal epidural injections is frequently related to inadvertent vascular injection of corticosteroids. Several methods have been proposed to reduce the risk of vascular injection, but none have demonstrated efficacy. Because of the fleeting appearance of vascular contrast patterns, live fluoroscopy is recommended during contrast injection. Despite this, many practitioners continue to use intermittent fluoroscopy. Methods. During 50 epidural injections dynamic contrast flow was observed under live fluoroscopy, and the “dynamic true” image was determined. Two intermittent fluoroscopy images were saved from each injection, the first just before completing the contrast injection (“static C” image), and another 1 second after the contrast injection ceased (“static PC” image). Five physicians with experience performing these injections independently interpreted the 100 randomly ordered static images. Accuracy of intermittent fluoroscopy was determined by comparing the interpretation of the 100 static images with the dynamic true patterns observed under live fluoroscopy. Results. Overall, interpretation of the static images missed 57% of the vascular injections. Timing of the static images influenced accuracy with the static C images missing 50% of vascular injections, and the static PC images missing 68% of vascular injections (P = 0.075). Accuracy was significantly worse when vascular injections occurred simultaneous to the expected epidural injection (P = 0.041), and in lumbar images (P = 0.012). Conclusion. Based on these findings, we recommend use of live fluoroscopy to observe dynamic contrast flow during transforaminal epidural steroid injections.

Does physical activity influence the relationship between low back pain and obesity

BACKGROUND CONTEXT Evidence supporting an association between obesity and low back pain (LBP) continues to grow; yet little is known about the cause and effect of this relationship. Even less is known about the mechanisms linking the two. Physical activity is a logical suspect, but no study has demonstrated its role. PURPOSE This study was designed to examine the interrelationship between physical activity, obesity, and LBP. The specific aims were to determine if obesity is a risk factor for LBP in the U.S. population, measure the strength of any observed association, and evaluate the role of physical activity in modulating this association. STUDY DESIGN/SETTING A cross-sectional U.S. population-based study. PATIENT SAMPLE A cohort of 6,796 adults from the 2003-2004 National Health and Nutrition Examination Survey. OUTCOME MEASURES Demographic information, an in-depth health questionnaire, physical examination details, and 7-day free-living physical activity monitoring using accelerometry (ActiGraph AM-7164; ActiGraph, Pensacola, FL, USA). METHODS LBP status was determined by questionnaire response. Body mass index (BMI) was calculated during physical examination and divided here into four groups (normal weight <25, overweight 25-30, obese 31-35, and ultraobese 36+). Summary measures of physical activity were computed based on intensity cutoffs, percentile intensities, and bout. Demographics, social history, and comorbid health conditions were used to build adjusted weighted logistic regression models constructed using Akaike Information Criterion. All displayed estimates are significant at level <.05. No external funding was received to support this study. None of the authors report conflicts of interest directly related to the specific subject matter of this manuscript. RESULTS In the U.S. population, the risk of low LBP increases in step with BMI from 2.9% for normal BMI (20-25) to 5.2% for overweight (26-30), 7.7% for obese (31-35), and 11.6% for ultraobese (36+). Smoking is consistently the strongest predictor of LBP across the BMI spectrum (odds ratio 1.6-2.9). Physical activity also modulates these risks. In the overall model, the best physical activity predictors of LBP are in the moderate and high intensity ranges with small effects (odds ratio 0.98 and 0.996 per standard deviation increase, respectively). When broken down by BMI, time spent in sedentary and moderate activity ranges demonstrate more robust influences on LBP status in the overweight, obese, and ultraobese groups. CONCLUSIONS Increased BMI is a risk factor for back pain in Americans. More important, the role of physical activity in mitigating back pain risk is shown to be of greater consequence in the overweight and obese populations.

Utility of the anesthetic test dose to avoid catastrophic injury during cervical transforaminal epidural injections

BACKGROUND CONTEXT Reports of serious complications from cervical transforaminal epidural corticosteroid injections often consider accidental intra-arterial injection the most likely mechanism of injury. As a result, many physicians have instituted methods to prevent intravascular injections. Routine use of the anesthetic test dose is one such method. The utility of the anesthetic test dose in this function has not been characterized in the current literature. PURPOSE The aim of this study was to determine the utility of injecting an anesthetic test dose before cervical transforaminal epidural corticosteroid injection and estimate the rate of false-negative intravascular contrast injection using live fluoroscopy and digital subtraction angiography (DSA). STUDY DESIGN Two-center retrospective study. PATIENT SAMPLE A consecutive cohort of men and women, ages of 23 to 83, who underwent cervical transforaminal epidural injection and received the anesthetic test dose after contrast injection was negative for vascular uptake, observed using live fluoroscopy or DSA. OUTCOME MEASURES Response to the anesthetic test dose was documented in each procedure note and recorded as either positive or negative. METHODS Records of three physiatrists at two academic spine centers (Center A and Center B) were reviewed to identify all patients who received a cervical transforaminal epidural injection during the preceding 5 years, resulting in a cohort of consecutively treated patients at each center. Each patient record was reviewed for demographics, indication for injection, procedure level and side, needle gauge, use of DSA, volume and type of anesthetic test dose used, and result of test dose injection. The test dose was considered positive if the following occurred: agitation or other sudden central nervous system change; gross motor deficits and/or paresthesias in the trunk, legs, or contralateral arm; systemic symptoms of anesthetic toxicity including cardiac arrhythmia, perioral numbness, metallic taste, dizziness, and/or ringing in the ear. For analysis, injections were separated into groups to compare results at Center A to Center B and to compare injections that used DSA to those that did not. The incidence of a positive response was calculated as a percentage from the total number of injections in the group. Differences between groups were analyzed for statistical significance using the Fisher exact test. RESULTS Six hundred seventy-eight injections were included. Of these, 349 were performed at Center A with test doses given after contrast injection under live fluoroscopy. The remaining 329 were performed at Center B, 183 also using live fluoroscopy, and 146 using DSA. The overall incidence of a positive anesthetic test dose was 0.59% (4/678). There was no significant difference between the incidence at each of the two centers (0.86% [3/349] vs. 0.30% [1/329]; p=.63). The overall incidence after live fluoroscopy was 0.75% (4/532) and after DSA was 0% (0/146), but this difference was not statistically significant (p=.58). Positive symptoms elicited by test dose administration included midneck and contralateral arm pain, metallic taste, dizziness, tachycardia, full body paresthesias, auditory changes, slurred speech, and motor ataxia. In all four cases with a positive response, the procedure was immediately terminated, symptoms resolved, and no lasting complications were observed. CONCLUSIONS The routine use of an anesthetic test dose appears to be safe and capable of detecting potentially dangerous intravascular injections undetected by conventional techniques. Positive responses occur in a small portion of those who receive the test dose injection. Further studies are required to determine the optimal dose and concentration of anesthetic to be used and the time required for observation after test dose administration.

Duration of Fluoroscopic-Guided Spine Interventions and Radiation Exposure Is Increased in Overweight Patients

The impact of patient body mass index (BMI) on image‐guided spine interventions remains unknown. Higher BMI is known to complicate the acquisition of radiographic images. Therefore it can be hypothesized that the patients body habitus can influence the delivery of a spinal injection.

Incidence of simultaneous epidural and vascular injection during cervical transforaminal epidural injections.

Study Design. Prospective, observational in vivo study. Objective. The aim of this study was to determine the incidence of simultaneous epidural and vascular contrast injection during cervical transforaminal epidural injections. Summary of Background Data. In the lumbar spine, vascular contrast patterns are more than twice as likely to appear simultaneous to the anticipated epidural pattern, than they are to occur alone. This is important because practitioners are more likely to miss a vascular pattern when it appears simultaneous to the expected epidural flow. The incidence of intravascular penetration in cervical transforaminal epidural injections is known to exceed than that of lumbar injections, however, no study has determined the incidence of simultaneous epidural and vascular injection in the cervical spine. Methods. Contrast patterns were observed with live fluoroscopy during 121 injections performed on 82 patients and categorized as one of the following: epidural only, vascular only, or simultaneous epidural and vascular. Results. The incidence of simultaneous epidural and vascular injection during cervical transforaminal epidural injections was 18.9%. The incidence of vascular only injection was 13.9%, for a total vascular injection incidence of 32.8%. There was no correlation between the observed contrast pattern with patients’ age, sex, side of injection, needle gauge, or diagnosis. There was a significant correlation between the level of injection and the risk of vascular injection. The higher the injection level, the higher the probability of a vascular injection. Fluoroscopy time was significantly increased when a vascular injection was identified. Conclusion. Simultaneous epidural and vascular injection accounts for over half of all vascular injections during cervical transforaminal epidural injections. With the risk of severe complications and high incidence of vascular injections in the cervical spine, live fluoroscopy is recommended during contrast injection with specific attention to simultaneous epidural and vascular flow.

Influence of needle type on the incidence of intravascular injection during transforaminal epidural injections: a comparison of short-bevel and long-bevel needles

BACKGROUND CONTEXT Vascular penetration and injection of corticosteroids into a vessel during lumbosacral transforaminal epidural injection is a suspected cause of myelopathy. Blunt needles have been suggested to avoid vascular penetration, but they are difficult to navigate. Another alternative to the standard long-bevel sharp needles is the short-bevel needles. Some have postulated that short-bevel needles are the best option for high-risk spine injections because they maintain navigation characteristics while potentially reducing the risk of complications. To date, no studies have been performed to either confirm or refute this. PURPOSE The purpose of this study was to determine if there is a difference in the incidence of vascular penetration during lumbosacral transforaminal epidural injections between short-bevel and long-bevel needles. STUDY DESIGN/SETTING This is a prospective, observational, in vivo study. PATIENT SAMPLE The sample comprises patients receiving lumbosacral transforaminal epidural injections at a university-based outpatient spine center. OUTCOME MEASURE The outcome measure was the incidence of vascular contrast patterns observed under live fluoroscopy. METHODS One interventional spine physician recorded contrast patterns observed during 158 fluoroscopically guided lumbosacral transforaminal epidural injections under live fluoroscopy using two different types of needle tips. RESULTS Vascular injections were observed in 22 of the 158 injections, for an overall incidence of 13.9%. The incidence of vascular injections in the short-bevel group was 15.6% (10/64) and in the long-bevel group was 12.8% (12/94). This difference was not statistically significant (p=.6447). A secondary analysis was performed to determine if the needle gauge influenced the incidence of vascular injections, and again, there were no statistical differences in the overall rates of vascular injection. CONCLUSIONS In comparison with long-bevel needles, short-bevel needles do not reduce the risk of inadvertent vascular injection in lumbosacral transforaminal epidural injections.

Nociception before and after exercise in rats bred for high and low aerobic capacity

Exercise and stress are known to influence pain perception. However, little is known about how level of fitness influences pain perception and the experience of pain. In the present study, pain perception before and after exercise to exhaustion was examined in 6 rats systematically bred to have a high aerobic capacity (HCR animals) and 6 rats systematically bred to have a low aerobic capacity (LCR animals). HCR animals had significantly higher pain thresholds compared to LCR animals before and after exercise (7.66 s compared to 6.01 s, t=-3.07, p<0.05; and 6.89 s versus 4.73 s, t=-3.73, p<0.01, respectively). In addition, both groups of animals displayed evidence of hyperalgesia following exercise compared to baseline. However, the pain thresholds of HCR animals returned to baseline levels faster than LCR animals following exercise. The findings support the hypothesis that level of fitness plays a role in the perception of pain. In addition, a higher level of fitness may serve as buffer against the effects of stress and help to reduce or prevent the experience of clinical pain. Further research is needed to examine the mechanisms that underlie this phenomenon.

Vascular causes of radiculopathy: a literature review

BACKGROUND CONTEXT Vascular etiologies are a significant source of radiculopathy. The entities that are reviewed here include epidural spinal hematoma, subdural spinal hematoma, spinal arteriovenous malformation, vertebral hemangioma, spinal epidural cavernous hemangioma, vertebral artery anomalies (both tortuosity and dissection), aortic aneurysm, hemorrhagic synovial cysts, ligamentum flavum hematoma, and venous varices. The incidence, pathophysiology, typical clinical presentation, appropriate diagnostic workup, and management are summarized. PURPOSE To review and summarize various vascular causes of radiculopathy and how it impacts the management of patients with radicular spinal pain. STUDY DESIGN Literature review. METHODS An extensive literature review was done on each of the vascular entities and their presentation as radiculopathy. RESULTS Vascular etiologies of radiculopathy may be underestimated in the literature. Imaging in addition to the history and physical examination is essential to identifying vascular sources of radiculopathy and establishing correct treatment. CONCLUSIONS In examining patients with radicular pain, extraspinal causes of radiculopathy including vascular entities should be included in the differential. Knowledge of the incidence, pathophysiology, clinical presentation, and management of the possibly underreported various vascular causes of radiculopathy increase the ability of the physician to provide optimal care for the patient. A key aspect to identifying such vascular lesions is appropriate imaging for documenting the source of radiculopathy. Blind injections, done without appropriate imaging for identifying the cause of radiculopathy, and also performed without fluoroscopic guidance, increase not only the risk of misdiagnosis but also the comorbidities associated with spinal injections.