The positive prediction of single photon emission computed tomography/ computed tomography (SPECT/CT) in the outcome of intervention for cervical facet pain.

BACKGROUND CONTEXT: Previous studies have reported that magnetic resonance imaging (MRI) and computed tomography (CT) do not predict response to facet blocks. However, single photon emission computed tomography (SPECT) uptake within facet joints has been shown to correlate with pain relief after intervention in the lumbar spine. There is minimal data regarding the predictive value of single photon emission computed tomography/computed tomography (SPECT/CT) for neck pain. PURPOSE: The aim of this study was to evaluate the utility of SPECT/CT in patients with axial neck pain for the identification of specific facet joints that would benefit from diagnostic and therapeutic facet joint steroid injections and/or medial branch block/RFA treatments. STUDY DESIGN: A retrospective cohort study. PATIENT SAMPLE: One hundred seventy-nine patients at a single institution pain center with neck pain and a SPECT/CT scan between 2009 and 2015. One hundred twelve patients had no prior intervention at the level of interest and met inclusion criteria. OUTCOME MEASURES: Pain reduction at 50% and 80% thresholds within 24 hours of facet intervention. Concordance of facet intervention with the focus of maximal uptake on SPECT/CT scan. METHODS: All patients were referred to our institution's Center for Pain Medicine and were treated with facet interventions. The site of facet intervention was determined by pain center providers based on their clinical examination and interpretation of images. Groups were formed based on whether the facet intervention included the level of maximal uptake on SPECT/CT scan. A positive response to intervention was defined at both 50% and 80% thresholds for reduction in pain within 24 hours of facet injection with steroid and local anesthetic or medial branch block with local anesthetic only. These were the facet interventions used for our data collection. A Chi-square statistic was used to analyze categorical data and a Student's t-test was used to analyze non-categorical data. SPSS (IBM Corp. IBM SPSS Version 24.0) was used for all analyses. RESULTS: Of our 112 patients, Group 1 consisted of 89 with an intervention occurring at the level with increased uptake on SPECT/CT. Group 2 consisted of 23 patients with an intervention at a level without uptake on SPECT/CT. Demographic data did not significantly differ between cohorts. A Chi-square test of independence demonstrated that intervention at a level concordant with SPECT/CT was significantly correlated with self-reported pain relief thresholds of both 50% and 80% (p=.0002). CONCLUSIONS: Facet interventions based on SPECT/CT scan uptake were more successful in pain reduction than those which were not. This suggests a role for SPECT/CT in diagnosing therapeutic targets for neck pain.

Two-Year Outcomes From a Prospective Multicenter Investigation Device Trial of a Novel Conformal Mesh Interbody Fusion Device.

BACKGROUND: Interbody fusion is a widely utilized and accepted procedure to treat advanced debilitating lumbar degenerative disc disease (DDD). Increasingly, surgeons are seeking interbody devices that are large for stability and grafting purposes but can be inserted with less invasive techniques. To achieve these contrary objectives a novel, conformable mesh interbody fusion device was designed to be placed in the disc space through a small portal and filled with bone graft in situ to a large size. This design can reduce the risk of trauma to surrounding structures while creating a large graft footprint that intimately contours to the patient's own anatomy. The purpose of this Investigational Device Exempt (IDE) trial was to evaluate the perioperative and long-term results of this novel conformable mesh interbody fusion device. METHODS: This investigation is a prospective, multicenter, single-arm, Food and Drug Administration and Institutional Review Board-approved IDE, performance goal trial. A total of 102 adults presenting with DDD at a single level between L2 and S1 and unresponsive to 6 months conservative care had instrumented lumbar interbody fusion. Validated assessment tools include 100 mm visual analog scale for pain, Oswestry Disability Index (ODI) for function, single question survey for patient satisfaction, and computed tomography (CT) scan for fusion. Patients were enrolled across 10 geographically distributed sites. Pain/ODI surveys, physical evaluations, and imaging were performed serially through 24 months. Specifically, CT was performed at 12 and, if not fused, 24 months. Independent radiologists assessed CTs for fusion. An independent committee adjudicated adverse events. Patients with complete data at 24 months were included in the analysis. RESULTS: Ninety-six (96, 94% follow-up rate) patients (57.0 ± 12.0 years, 50.0% female, Body Mass Index 30.6 ± 4.9) reported average decreased low back pain from baseline of 45.0 ± 26.6 at 6 weeks and 51.4 ± 26.2 at 24 months. Right/left leg pain reduced by 28.9 ± 36.7/37.8±32.4 at 6 weeks and 30.5±33.0/40.3 34.6 at 24 months. Mean ODI improved 17.1 ± 18.7 from baseline to 6 weeks and 32.0 ± 18.5 by 24 months. At 24 months, 91.7% of patients rated their procedure as excellent/good. Fusion rates were 97.9% (94/96) at 12 months, and 99% (95/96) at 24 months. Mean operative time, estimated blood loss, and length of stay were 2.6 ± 0.9 hours, 137 ± 217 mL, and 2.3 ± 1.2 days, respectively. No device-related serious adverse events have occurred. CONCLUSIONS: Clinically significant outcomes for pain, function, fusion, and device safety were demonstrated in this population. Substantial clinical improvements occur by 6 weeks postoperative and continue to improve to 24 months. The successful outcomes observed in this trial support use of this novel device in an instrumented lumbar interbody fusion. LEVEL OF EVIDENCE: 3. CLINICAL RELEVANCE: This reports substantiates that the preliminary 1-year findings published earlier for this investigation are confirmed and the fusion rates and that patient improvements reported are sustained through 2 years.

Ultrasound evidence of altered lumbar connective tissue structure in human subjects with chronic low back pain.

BACKGROUND: Although the connective tissues forming the fascial planes of the back have been hypothesized to play a role in the pathogenesis of chronic low back pain (LBP), there have been no previous studies quantitatively evaluating connective tissue structure in this condition. The goal of this study was to perform an ultrasound-based comparison of perimuscular connective tissue structure in the lumbar region in a group of human subjects with chronic or recurrent LBP for more than 12 months, compared with a group of subjects without LBP. METHODS: In each of 107 human subjects (60 with LBP and 47 without LBP), parasagittal ultrasound images were acquired bilaterally centered on a point 2 cm lateral to the midpoint of the L2-3 interspinous ligament. The outcome measures based on these images were subcutaneous and perimuscular connective tissue thickness and echogenicity measured by ultrasound. RESULTS: There were no significant differences in age, sex, body mass index (BMI) or activity levels between LBP and No-LBP groups. Perimuscular thickness and echogenicity were not correlated with age but were positively correlated with BMI. The LBP group had approximately 25% greater perimuscular thickness and echogenicity compared with the No-LBP group (ANCOVA adjusted for BMI, p<0.01 and p<0.001 respectively). CONCLUSION: This is the first report of abnormal connective tissue structure in the lumbar region in a group of subjects with chronic or recurrent LBP. This finding was not attributable to differences in age, sex, BMI or activity level between groups. Possible causes include genetic factors, abnormal movement patterns and chronic inflammation.

Dynamic morphometric characterization of local connective tissue network structure in humans using ultrasound.

BACKGROUND: In humans, connective tissue forms a complex, interconnected network throughout the body that may have mechanosensory, regulatory and signaling functions. Understanding these potentially important phenomena requires non-invasive measurements of collagen network structure that can be performed in live animals or humans. The goal of this study was to show that ultrasound can be used to quantify dynamic changes in local connective tissue structure in vivo. We first performed combined ultrasound and histology examinations of the same tissue in two subjects undergoing surgery: in one subject, we examined the relationship of ultrasound to histological images in three dimensions; in the other, we examined the effect of a localized tissue perturbation using a previously developed robotic acupuncture needling technique. In ten additional non-surgical subjects, we quantified changes in tissue spatial organization over time during needle rotation vs. no rotation using ultrasound and semi-variogram analyses. RESULTS: 3-D renditions of ultrasound images showed longitudinal echogenic sheets that matched with collagenous sheets seen in histological preparations. Rank correlations between serial 2-D ultrasound and corresponding histology images resulted in high positive correlations for semi-variogram ranges computed parallel (r = 0.79, p < 0.001) and perpendicular (r = 0.63, p < 0.001) to the surface of the skin, indicating concordance in spatial structure between the two data sets. Needle rotation caused tissue displacement in the area surrounding the needle that was mapped spatially with ultrasound elastography and corresponded to collagen bundles winding around the needle on histological sections. In semi-variograms computed for each ultrasound frame, there was a greater change in the area under the semi-variogram curve across successive frames during needle rotation compared with no rotation. The direction of this change was heterogeneous across subjects. The frame-to-frame variability was 10-fold (p < 0.001) greater with rotation than with no rotation indicating changes in tissue structure during rotation. CONCLUSION: The combination of ultrasound and semi-variogram analyses allows quantitative assessment of dynamic changes in the structure of human connective tissue in vivo.

Comparison of three lumbar orthoses using motion assessment during task performance.

STUDY DESIGN: Four conditions (three orthoses, one no orthosis), full cross-over, randomized order, 12 subjects tested 3 months after a lumbar surgical arthrodesis. OBJECTIVES: To assess whole torso and lumbar motions and comfort for each orthoses condition during performance of activities of daily living. SUMMARY OF BACKGROUND DATA: Previous noninvasive studies measured whole torso (not just lumbar) movement. Recent development of a low profile, flexible, strain-gauged device ("Lordosimeter") facilitated this study. MATERIALS AND METHODS: The Lordosimeter was taped to the skin along the midline of the lumbosacral region. Orthoses studied were Boston anterior opening, Aspen lumbosacral, and Cybertech. Specified activities of daily living were performed for each orthosis condition. Subject effort during the flexion/extension task was assessed by surface electromyography (EMG). Comfort was assessed by visual analog scale. RESULTS: There were no significant differences in EMG between orthoses. For lumbar flexion, trunk flexion, total lumbar motion, and total trunk motion, the mean values for Aspen and Boston (but not Cybertech) were significantly smaller than for no orthosis for most of the tasks and there were no significant differences between Aspen and Boston. The total lumbar motion allowed by each orthosis (averaged across tasks and relative to the no orthosis condition) was 81% for Aspen, 79% for Boston, and 97% for Cybertech. The comfort rating averaged across tasks was 2.24 for Aspen, 4.12 for Boston, and 3.92 for Cybertech (0 = very comfortable, 10 = very uncomfortable). Aspen was significantly more comfortable than Boston or Cybertech. Boston and Cybertech did not differ significantly. CONCLUSIONS: The Lordosimeter is useful for measuring lumbar motion during orthosis wear. The Aspen and the Boston orthoses provided significant flexion-extension motion restriction compared with no orthosis, but for almost all of the motion measures did not differ from each other. The Cybertech did not differ significantly from the no orthosis condition. The Aspen orthosis was rated significantly more comfortable than the Boston or the Cybertech.

Influence of fixed charge density magnitude and distribution on the intervertebral disc: applications of a poroelastic and chemical electric (PEACE) model.

A 3-dimensional formulation for a poroelastic and chemical electric (PEACE) model is presented and applied to an intervertebral disc slice in a 1-dimensional validation problem and a 2-dimensional plane stress problem. The model was used to investigate the influence of fixed charge density magnitude and distribution on this slice of disc material. Results indicated that the mechanical, chemical, and electrical behaviors were all strongly influenced by the amount as well as the distribution of fixed charges in the matrix. Without any other changes in material properties, alterations in the fixed charge density (proteoglycan content) from a healthy to a degenerated distribution will cause an increase in solid matrix stresses and can affect whether the tissue imbibes or exudes fluid under different loading conditions. Disc tissue with a degenerated fixed charge density distribution exhibited greater solid matrix stresses and decreased streaming potential, all of which have implications for disc nutrition, disc biomechanics, and tissue remodeling. It was also seen that application of an electrical potential across the disc can induce fluid transport.

Evidence of connective tissue involvement in acupuncture.

Acupuncture needle manipulation gives rise to "needle grasp," a biomechanical phenomenon characterized by an increase in the force necessary to pull the needle out of the tissue (pullout force). This study investigates the hypothesis that winding of connective tissue, rather than muscle contraction, is the mechanism responsible for needle grasp. We performed 1) measurements of pullout force in humans with and without needle penetration of muscle; 2) measurements of pullout force in anesthetized rats, with and without needle rotation, followed by measurements of connective tissue volume surrounding the needle; 3) imaging of rat abdominal wall explants, with and without needle rotation, using ultrasound scanning acoustic microscopy. We found 1) no evidence that increased penetration of muscle results in greater pullout force than increased penetration of subcutaneous tissue; 2) that both pullout force and subcutaneous tissue volume were increased by needle rotation; 3) that increased periodic architectural order was present in subcutaneous tissue with rotation, compared with no rotation. These data support connective tissue winding as the mechanism responsible for the increase in pullout force induced by needle rotation. Winding may allow needle movements to deliver a mechanical signal into the tissue and may be key to acupuncture's therapeutic mechanism.