Internal Disc Disruption Research Articles

Lumbar spine endplate fractures: Biomechanical evaluation and clinical considerations through experimental induction of injury.

Lumbar endplate fractures were investigated in different experimental scenarios, however the biomechanical effect of segmental alignment was not outlined. The objectives of this study were to quantify effects of spinal orientation on lumbar spine injuries during single-cycle compressive loads and understand lumbar spine endplate injury tolerance. Twenty lumbar motion segments were compressed to failure. Two methods were used in the preparation of the lumbar motion segments. Group 1 (n = 7) preparation maintained pre-test sagittal lordosis, whereas Group 2 (n = 13) specimens had a free-rotational end condition for the cranial vertebra, allowing sagittal rotation of the cranial vertebra to create parallel endplates. Five Group 1 specimens experienced posterior vertebral body fracture prior to endplate fracture, whereas two sustained endplate fracture only. Group 2 specimens sustained isolated endplate fractures. Group 2 fractures occurred at approximately 41% of the axial force required for Group 1 fracture (p < 0.05). Imaging and specimen dissection indicate endplate injury consistently took place within the confines of the endplate boundaries, away from the vertebral periphery. These findings indicate that spinal alignment during compressive loading influences the resulting injury pattern. This investigation identified the specific mechanical conditions under which an endplate breach will take place. Development of endplate injuries has significant clinical implication as previous research identified internal disc disruption (IDD) and degenerative disc disease (DDD) as long-term consequences of the axial load-shift that occurs following a breach of the endplate. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1084-1091, 2016.

Behavioral signs of axial low back pain and motor impairment correlate with the severity of intervertebral disc degeneration in a mouse model

Background ContextChronic low back pain is debilitating and difficult to treat. Depending on the etiology, responses to treatments vary widely. Although chronic low back pain is frequently related to intervertebral disc degeneration, the relationship between disc degeneration severity and clinical symptoms are still poorly understood.In humans, studies investigating the relationship between disc degeneration severity and low back pain are limited by the difficulty of obtaining disc samples from well-characterized patients and pain-free controls. We have previously described the secreted protein, acidic, rich in cysteine (SPARC)-null mouse model of chronic low back pain. SPARC is a matricellular protein involved in regulating the assembly and composition of extracellular matrix. The SPARC-null mice develop age-dependent disc degeneration of increasing severity accompanied by behavioral signs suggestive of axial low back pain, radiating leg pain, and motor impairment. The existence of this model allows for examination of the relationships between clinical symptoms in vivo and pathological signs of disc degeneration ex vivo. PurposeThe goal of this study was to explore the relationship between behavioral signs of pain and the severity of lumbar disc degeneration using the SPARC-null mouse model of disc degeneration-related low back pain. Study DesignThis study used a cross-sectional, multiple-cohort behavioral and histological study of disc degeneration and behavioral symptoms in a mouse model of low back pain associated with disc degeneration. MethodsSPARC-null and wild-type control mice ranging from 6 to 78 weeks of age were used in this study. The severity of disc degeneration was determined by ex vivo analysis of the lumbar spine using colorimetric histological staining and a scoring system adapted from the Pfirrmann scale. Behavioral signs of axial low back pain, radiating leg pain, and motor impairment were quantified as tolerance to axial stretching in the grip force assay, hypersensitivity to cold or mechanical stimuli on the hindpaw (acetone and von Frey tests), and latency to fall in the rotarod assay, respectively. ResultsThe SPARC-null mice exhibited decreased tolerance to axial stretching, hindpaw cold hypersensitivity, and motor impairment compared with age-matched control mice. The severity of disc degeneration increased with age in both SPARC-null and control mice and by 78 weeks of age, the same proportion of lumbar discs were abnormal in SPARC-null and control mice. However, the degree of degeneration was more severe in the SPARC-null mice. In both SPARC-null and control mice, tolerance to axial stretching but not hindpaw cold sensitivity correlated with disc degeneration severity. Motor impairment correlated with degeneration severity in the SPARC-null mice only. ConclusionsThese data suggest that internal disc disruption contributes to axial low back pain and motor impairment but not to radiating leg pain. These results have implications for the optimization of mechanism-based treatments strategies.

Prevalence and Characteristics of Discogenic Pain in Tertiary Practice: 223 Consecutive Cases Utilizing Lumbar Discography.

Between 26% and 42% of chronic low back pain is attributed to internal disc disruption of lumbar intervertebral discs. These prevalence estimates and data characterizing discogenic pain originate largely from research at elite practices, conducted 20 years ago. With few studies since, their concordance with rates in community practice has rarely been addressed. To assess the prevalence and key features of discogenic pain within community-based tertiary practice, and to evaluate the accuracy and clinical utility of discography. This prospective, three-year study of 223 consecutive cases of chronic low back pain used image-guided lumbar discography to identify symptomatic and flanking asymptomatic discs. A subset of patients (n = 195) had previously undergone posterior column blocks to investigate spinal facet and/or sacroiliac joints as contributing pain sources. A total of 644 discs were tested without infection or complication. Positive discograms were recorded in 74% of patients, with 22.9% negative and 3.1% assessed as indeterminate. Among patients receiving both discography and diagnostic blocks, 63% had proven discogenic pain, 18% had pain of mixed etiology and 14% remained undiagnosed. Taking into account all low back pain cases during this study (n = 756), discogenic pain prevalence was 21.8% (95% CI: 17-26%). The prevalence of discogenic pain in this community practice is below the range, but within confidence intervals, previously reported. Prevalence is considerably elevated, however, among well-selected patients and discography enabled a firm diagnosis in most such cases. These findings are broadly in keeping with those reached in key publications and support the clinical utility of discography.

Paeoniflorin inhibits nucleus pulposus cell apoptosis by regulating the expression of Bcl-2 family proteins and caspase-9 in a rabbit model of intervertebral disc degeneration.

Apoptosis plays a key role in the pathogenesis of internal disc disruption (IDD); therefore, the inhibition of apoptosis may offer a novel approach for treating IDD diseases. The aim of the present study was to investigate the effects and the underlying mechanisms of paeoniflorin through the detection of relevant indicators in a rabbit model of IDD. In total, 144 rabbits were used in the study and divided into four groups (n=36 per group). Rabbits successfully modeled with IDD received an intragastric injection of 120 mg/kg·day paeoniflorin (high-dose group), 30 mg/kg·day paeoniflorin (low-dose group) or saline (model saline group), while rabbits without IDD were used as a normal control group. The apoptosis rate of disc nucleus pulposus cells was detected using flow cytometry. In addition, the expression levels of Bcl-2, Bax and caspase-9 in the disc tissues were detected using immunohistochemistry and western blot analysis prior to and following the treatment. The results indicated that the expression levels of Bax in the low- and high-dose paeoniflorin groups were significantly reduced, while the Bcl-2 expression levels were significantly increased when compared with the model saline group (P<0.01). In addition, the expression levels of cleaved caspase-3 and cleaved caspase-9 were reduced in the low- and high-dose paeoniflorin groups, as compared with the model saline group (P<0.05). Furthermore, the average apoptotic index of the high- and low-dose paeoniflorin groups was decreased when compared with the model saline group (P<0.05). In conclusion, paeoniflorin was demonstrated to inhibit the apoptosis of nucleus pulposus cells and the activation of caspase-3 and caspase-9 through the regulation of Bcl-2 family protein expression. These results provide an experimental basis for the future treatment of IDD with paeoniflorin.

Spinal pain

The spinal pain, and expecially the low back pain (LBP), represents the second cause for a medical consultation in primary care setting and a leading cause of disability worldwide [1]. LBP is more often idiopathic. It has as most frequent cause the internal disc disruption (IDD) and is referred to as discogenic pain. IDD refers to annular fissures, disc collapse and mechanical failure, with no significant modification of external disc shape, with or without endplates changes. IDD is described as a separate clinical entity in respect to disc herniation, segmental instability and degenerative disc desease (DDD). The radicular pain has as most frequent causes a disc herniation and a canal stenosis. Both discogenic and radicular pain also have either a mechanical and an inflammatory genesis. For to be richly innervated, facet joints can be a direct source of pain, while for their degenerative changes cause compression of nerve roots in lateral recesses and in the neural foramina. Degenerative instability is a common and often misdiagnosed cause of axial and radicular pain, being also a frequent indication for surgery. Acute pain tends to extinguish along with its cause, but the setting of complex processes of peripheral and central sensitization may influence its evolution in chronic pain, much more difficult to treat.The clinical assessment of pain source can be a challenge because of the complex anatomy and function of the spine; the advanced imaging methods are often not sufficient for a definitive diagnosis because similar findings could be present in either asymptomatic and symptomatic subjects: a clinical correlation is always mandatory and the therapy cannot rely uniquely upon any imaging abnormalities. Purpose of this review is to address the current concepts on the pathophysiology of discogenic, radicular, facet and dysfunctional pain, focusing on the role of the imaging in the diagnostic setting, to potentially address a correct approach also to minimally invasive interventional techniques. Special attention will be done to the discogenic pain, actually considered as the most frequent cause of chronic low back pain.

Treatment of annular disc tears and “leaky disc syndrome” with fibrin sealant

The surfaces of annulus fibrosus tears are known harbingers of inflammatory constituents within intervertebral discs, stimulating sensitized nocioceptors within those tears. Other current treatment options of internal disc disruption neglect to specifically address the surface of these tears. Therefore, this investigation answers the question: does nonautologous fibrin sealant applied to the surface of annulus fibrosus tears mechanically glue and seal annular tears? Regarding this query, results suggest nonautologous concentrated fibrin successfully seals annulus fibrosus tears with a “suture-like mechanical sealant,” serving as a safe option for treating symptomatic or nonsymptomatic intervertebral disc tears. Sealing tears prevents pain-generating chemicals of the nucleus pulposus from leaking through annular tears. More specifically, fibrin sealant minimizes or eliminates extravasation of nucleus pulposus through tears and voids within the annulus fibrosus. Moreover, an investigation subjecting discs to an “internal pressure challenge” objectively affirms fibrin׳s ability to seal torn and degenerated discs against a pressure challenge. (1psi = 6.89476kPs (disc mean pressure pretreatment = 75.84kPs; post-treatment = 179.3kPs: (n = 347, P < 0.001). Therefore, sealing annular tears serves to minimize extravasation of nucleus pulposus through annular tears, thus potentially treating symptoms caused by internal disc disruption, “Leaky Disc Syndrome,” and chemical radiculopathy. Additionally, sealing annular tears potentially allows adjunctive regenerative biologics such as mesenchymal precursor cells, platelet rich plasma, and growth factors to remain within discs, thus, potentially optimizing their efficacy. A prior in vivo investigation demonstrated the vast majority of mesenchymal stem cells leaked from animal intravertebral discs, and another demonstrated radiolabeled mesenchymal stem cells leaked from degenerated discs and were subsequently found within new exuberant osteophytes adjacent to the degenerated disc. Intra-annular nonautologous concentrated fibrin shares a benefit of other intradiscal biologics in that fibrin does not cause aberrant detrimental mechanical forces on adjacent discs, compared with surgical fusion and disc arthrodesis, which both cause aberrant, potentially damaging mechanical forces on adjacent segments. The mean number of morphologically abnormal lumbar intervertebral discs in this population with chronic low back pain was 3.21 discs.

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Low back pain (LBP) is one of the most prevalent, disabling and costly medical conditions affecting modern society. LBP presents a significant challenge to effective treatment due to often multifactorial or unknown etiology. Since the 1980s, the sacroiliac (SI) joint has become increasingly recognized as a common source of LBP. In contrast to other sources of LBP such as internal disc disruption and even psychosocial factors, SI joint pain and degeneration are reliably identified with provocative manual tests and diagnostic injections. Fusion of the SI joint has been shown to provide enduring symptom relief, and minimally invasive techniques developed over the past decade have further reduced the operative risks associated with open fusion surgery. Minimally invasive SI joint fusion surgeries are typically performed by placing rigid implant components across the joint space. The implants provide mechanical fixation while bony fusion develops. Decortication of the SI joint space during the procedure produces a bleeding bone surface that allows for increased availability of autologous mesenchymal stem cells and growth factors at the fusion site. Coupled with the mechanical stability provided by the implant and autologous bone graft, decortication provides an optimal environment for bone growth and subsequent fusion of the joint. This report describes the background of SI joint disease, treatment, and the minimally invasive SImmetry? Sacroiliac Joint Fusion System (Zyga Technology, Inc., Minnetonka, MN, USA), with emphasis on the decortication instrumentation and procedure.

Patient selection and efficacy of intradiscal electrothermal therapy with respect to dallas discogram score

Intervertebral disc degeneration can cause severe low back pain. Intradiscal electrothermal therapy (IDET) is a minimally invasive treatment option for patients with symptomatic internal disc disruption unresponsive to conservative medical care. We aimed to evaluate 12-month pain and functional outcomes and predictors of clinical success in patients with discogenic back pain treated with IDET with respect to the Dallas Discogram Scale (DDS). This was a retrospective analysis of patients undergoing IDET for low back pain from 2009 through 2014 at Baskent University, Department of Neurosurgery. A total number of 120 consecutive patients data were collected retrospectively. The degree of disc degeneration was graded using the DDS during discography, and the presence of a high intensity zone (HIZ) on magnetic resonance (MR) imaging was noted. The primary outcome measure was assessment of back pain severity based on the Visual Analogue Scale (VAS); function was assessed by the Oswestry Disability Index (ODI). Follow-up examinations for ODI and VAS scores were assessed at 1, 6, and 12 months post-treatment. Outcomes were discussed with respect to morphological changes in intervertebral discs on discogram. There was an average 57.39% and 47.16% improvement in VAS and ODI scores, respectively, between pretreatment and 12 months follow-up (p < 0.0001 for both comparisons). Predictors of 12-month clinical success was depended on DDS (p < 0.0001), a HIZ on MR imaging (p < 0.0001). Durable clinical improvements can be realized after IDET in select surgical candidates with mild disc degeneration and HIZ, discography, and low-grade DDS, with more effective treatment results.

Effect of the mixture of bone marrow mesenchymal stromal cells and annulus fibrosus cells in repairing the degenerative discs of rabbits.

The aims of this study were to investigate the effect of a mixture of bone marrow mesenchymal stem cells (BMSCs) and annulus fibrosus cells (AFCs) in repairing the degenerative discs of rabbits, and to provide an experimental basis for its clinical application. BMSCs from rabbits were cultured in vitro and mixed with AFCs. The animal model of degenerative intervertebral disc was built by aspirating the nucleus pulposus (L3-4, L4-5, L5-6, and L6-7) through a posterolateral approach. Mixtures of BMSCs and AFCs (group A), BMSCs alone (B), or saline (C) were injected into test discs, and changes evaluated by plain radiographs, magnetic resonance imaging, and histology. After two weeks, each group showed typical internal disc disruption; stenosis of the intervertebral space, weakening T2 disc signal, decreased disc height and expression of type II collagen and glycosaminoglycan, and fibrosis of the nucleus pulposus. After cell transplantation, the disc heights in groups A and B were regained; however, they continued to decrease in group C. The transplanted cells survived in the discs, proliferated after transplantation, and produced copious matrix. Macroscopic and histological evaluations confirmed structural and nuclear preservation in cell-transplanted discs. The secretions and expressions of Type Ⅱ collagen and glycosaminoglycan in group A were statistically significant higher than those in group B (Type Ⅱ collagen, group A 141.6 ± 5.87, group B 139.8 ± 8.65, P = 0.004; glycosaminoglycan, group A 3.008 ± 0.35, group B 2.94 ± 0.29, P = 0.003). Expression of type II collagen and glycosaminoglycan was significantly greater in group A than group B. Therefore, co-transplantation of BMSCs and AFCs can restore the extracellular matrix, making this approach superior to transplantation of BMSCs alone, which may be beneficial for the therapy of intervertebral disc degeneration.

Biomechanical Effect of Increasing Magnitudes of Internal Annular Disruption

Internal disc disruption (IDD) results from tearing of inner annulus fibers while the external aspect remains intact. This condition occurs traumatically or degeneratively, is not identifiable using non-contrast CT, and induces painful symptoms. Due to its occult nature on routine imaging, IDD may be a source of idiopathic pain in the absence of obvious degenerative changes. The mechanism of pain is related to instability resulting from fundamental changes in segmental load sharing that contribute to discogenic pain mechanisms and acute nerve root compression.

Diagnostic and therapeutic spinal interventions: Diskography.

Diskography (provocation diskography, disk stimulation) is an invasive diagnostic test performed to confirm or exclude internal disk disruption as the cause of axial spine pain. Diskography involves injecting fluid into the nucleus of the disk under manometric control; a positive response is reproduction of typical pain. Extensive but indirect literature validates diskography in the lumbar spine; it is less well-supported in the cervical or thoracic spine. Risks include rare instances of infection and neural injury; lumbar diskography may be associated with accelerated disk degeneration. Diskography has utility in establishing a diagnosis of diskogenic pain. When negative, it prevents inappropriate interventions directed at the disk; when positive, it prevents interventions directed at other axial pain generators. Its role in selecting patients for therapies directed at diskogenic pain is limited by the lack of available validated treatments.

Is Pain Blockage Safe? The Viewpoint Based on Nucleus Pulposus Cell Cytotoxicity

Introduction Local anesthetics combined with corticosteroids are commonly used for management of back pain in interventional spinal procedures. Several recent studies suggest cytotoxicity of bupivacaine, whereas others report protective and cytotoxic effects of corticosteroids on chondrocytes and intervertebral disc cells. Considering the frequent use of these agents in spinal interventions, it is meaningful to know how they affect intervertebral disc cells. This study was conducted to assess the effects of bupivacaine and triamcinolone, both alone and in combination, on viability of intervertebral disc cells in vitro. Materials and Methods Nucleus pulposus cells were isolated from human disc specimens from patients undergoing surgery due to disc herniation or degenerative disc disease. They were grown in three-dimensional alginate beads for 1 week to maintain their differentiated phenotypes and to allow for matrix formation before analysis. After 1 week of culture, the cells were exposed to bupivacaine (0.1, 0.25, 0.5, and 1%) or bupivacaine (0.1, 0.25, 0.5, and 1%) with 1 mg triamcinolone for 1, 3, or 6 hours. Cell viability was measured using trypan blue exclusion assay and flow cytometry. Live-cell/dead-cell fluorescent imaging was assessed using confocal microscopy. Results Trypan blue exclusion assays demonstrated dose- and time-dependent cytotoxic effects of bupivacaine on human nucleus pulposus cells. Similar but reduced cytotoxicity was observed after exposure to the combination of bupivacaine and 1 mg of triamcinolone. Flow cytometry showed a dose-dependent cytotoxic effect of bupivacaine on nucleus pulposus cells after 3 hours of exposure. The reduced cytotoxicity of bupivacaine combined with 1 mg triamcinolone was also confirmed in flow cytometry. Confocal images showed that the increase in dead cells correlated with the concentration of bupivacaine. Nevertheless, fewer cells died after exposure to several different concentrations of bupivacaine combined with 1 mg triamcinolone than did after exposure to bupivacaine alone. Conclusion The combination of bupivacaine and triamcinolone induced dose- and time-dependent cytotoxicity on human intervertebral disc cells in vitro, but the cytotoxicity was much weaker than that of bupivacaine alone. This study shows a potential protective influence of triamcinolone on intervertebral disc cells. Disclosure of Interest None declared References Hsiao CJ, Cherry DK, Beatty PC, Rechtsteiner EA. National Ambulatory Medical Care Survey: 2007 summary. Natl Health Stat Rep 2010; (27):1–32 Boswell MV, Trescot AM, Datta S, et al; American Society of Interventional Pain Physicians. Interventional techniques: evidence-based practice guidelines in the management of chronic spinal pain. Pain Physician 2007;10(1):7–111 Bogduk N. The lumbar disc and low back pain. Neurosurg Clin N Am 1991;2(4):791–806 Sehgal N, Fortin JD. Internal disc disruption and low back pain. Pain Physician 2000;3(2):143–157 Wetzel FT, LaRocca SH, Lowery GL, Aprill CN. The treatment of lumbar spinal pain syndromes diagnosed by discography. Lumbar arthrodesis. Spine 1994;19(7):792–800 Zucherman J, Hsu K, Picetti G III, White A, Wynne G, Taylor L. Clinical efficacy of spinal instrumentation in lumbar degenerative disc disease. Spine 1992;17(7):834–837 Choy DS, Ascher PW, Ranu HS, et al. Percutaneous laser disc decompression. A new therapeutic modality. Spine 1992;17(8):949–956 Onik G, Helms CA, Ginsburg L, Hoaglund FT, Morris J. Percutaneous lumbar diskectomy using a new aspiration probe. AJR Am J Roentgenol 1985;144(6):1137–1140 Wittenberg RH, Oppel S, Rubenthaler FA, Steffen R. Five-year results from chemonucleolysis with chymopapain or collagenase: a prospective randomized study. Spine 2001;26(17):1835–1841 Zhou Y, Abdi S. Diagnosis and minimally invasive treatment of lumbar discogenic pain—a review of the literature. Clin J Pain 2006;22(5):468–481

Pathological End Plate Alterations in Disc Degeneration

Discogenic pain accounts for approximately 40% of chronic low back pain cases, affecting 1 to 2 million adults between age 45 and 64 years in the United States. The putative pain generator in discogenic pain patients is usually considered intrinsic to the disc. Crock defined internal disc disruption as damage of internal disc structures while the external shape remains essentially normal, and no nerve root compression is present. However, the vertebral end plate is also a source of pain. It is the weak link during spinal compression, can sustain damage at loads well below those that cause disc herniation or vertebral fracture, and is innervated comparable to the outer annulus. Further evidence of the clinical importance of the vertebral end plate is the association between vertebral marrow abnormalities and discogenic pain. Data from multiple independent studies suggest that Modic Types I and II adjacent to the end plate are among the most specific of all MRI observations for predicting concordant discography-induced pain. In one prospective study, moderate-to-severe Modic Types I or II end plate abnormalities correlated 100% of the time with positive concordant pain at the adjacent disc. Recently, increased end plate innervation has also been reported for end plates with Modic changes. End plates serve as the interface between rigid vertebral bodies and pliant intervertebral discs. Because the lumbar spine carries significant forces and discs do not have a dedicated blood supply, end plates must balance conflicting requirements of being strong to prevent vertebral fracture and porous to facilitate transport between disc cells and vertebral capillaries. Consequently, end plates are particularly susceptible to damage, which can increase communication between proinflammatory disc constituents and vascularized vertebral bone marrow. End plate damage regions can be sites of reactive bone marrow lesions that include proliferating nerves, which are susceptible to chemical sensitization and mechanical stimulation. While several lines of evidence indicate that innervated end plate damage can be a source of chronic low back pain, its role in patients is likely underappreciated because innervated damage is poorly visualized with diagnostic imaging. This literature review summarizes end plate biophysical function and aspects of pathologic degeneration that can lead to vertebrogenic pain. Disclosure of Interest Consultant for Relievant MedSystems Consultant for Nocimed, LLC

Intradiscal Injection of Fibrin Sealant for the Treatment of Symptomatic Lumbar Internal Disc Disruption: Results of a Prospective Multicenter Pilot Study with 24-Month Follow-Up

Assess the safety and efficacy of intradiscal fibrin sealant in adults with chronic discogenic low back pain. Prospective, nonrandomized Food and Drug Administration approved pilot study. Three centers in the United States. Fifteen adults with chronic, single, or contiguous two-level lumbar discogenic pain confirmed through meticulous provocation discography. Volume- and pressure-controlled intradiscal delivery of BIOSTAT BIOLOGX(®) Fibrin Sealant with the Biostat(®) Delivery Device into symptomatic lumbar disc(s). Assessments were performed at baseline, 72 hours, and 1, 4, 13, 26, 52, and 104 weeks following intervention. Potential adverse events were evaluated with serial assessment of neurological status, radiographic, and magnetic resonance imaging (MRI). Efficacy measures included serial assessments of low back pain visual analog scale (VAS) measurements and the Roland-Morris Disability Questionnaire (RMDQ). Safety neurological assessments, X-ray, and MRI showed no significant changes. Adverse events were reported in nine subjects. Two instances of low back muscle spasm and one case of discitis were the only events considered related to the procedure or product. Mean low back pain VAS scores (mm) decreased from 72.4 (95% confidence interval 64.6-80.3) at baseline to 31.7 (17.4-46.1), 35.4 (17.7-53.1), and 33.0 (16.3-49.6); mean RMDQ score improved from 15.2 (12.7-17.7) at baseline to 8.9 (5.3-12.5), 6.2 (3.4-9.1), and 5.6 (2.9-8.4) at 26, 52, and 104 weeks, respectively. Intradiscal injection of BIOSTAT BIOLOGX Fibrin Sealant with the Biostat Delivery Device appears safe and may improve pain and function in selected patients with discogenic pain.

An Updated Review of Automated Percutaneous Mechanical Lumbar Discectomy for the Contained Herniated Lumbar Disc

Background: Lumbar disc prolapse, protrusion, and extrusion are the most common causes of nerve root pain and surgical interventions, and yet they account for less than 5% of all low back problems. The typical rationale for traditional surgery is that it is an effort to provide more rapid relief of pain and disability. It should be noted that the majority of patients do recover with conservative management. The primary rationale for any form of surgery for disc prolapse associated with radicular pain is to relieve nerve root irritation or compression due to herniated disc material. The primary modality of treatment continues to be either open or microdiscectomy, although several alternative techniques, including automated percutaneous mechanical lumbar discectomy, have been described. There is, however, a paucity of evidence for all decompression techniques, specifically alternative techniques including automated and laser discectomy. Study Design: A systematic review of the literature of automated percutaneous mechanical lumbar discectomy for the contained herniated lumbar disc. Objective: To evaluate and update the effectiveness of automated percutaneous mechanical lumbar discectomy. Methods: The available literature on automated percutaneous mechanical lumbar discectomy in managing chronic low back and lower extremity pain was reviewed. The quality assessment and clinical relevance criteria utilized were the Cochrane Musculoskeletal Review Group criteria, as utilized for interventional techniques for randomized trials, and the criteria developed by the Newcastle-Ottawa Scale criteria for observational studies. The level of evidence was classified as good, fair, and limited or poor, based on the quality of evidence scale developed by the U.S. Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to September 2012, and manual searches of the bibliographies of known primary and review articles. Outcome Measures: Pain relief was the primary outcome measure. Other outcome measures were functional improvement, improvement of psychological status, opioid intake, and return to work. Short-term effectiveness was defined as one year or less, whereas long-term effectiveness was defined as greater than one year. Results: Nineteen studies were included; none of the randomized trials and 19 observational studies met inclusion criteria for methodological quality assessment. Overall, 5,515 patients were studied with 4,412 patients (80%) showing positive results lasting one year or longer. Based on USPSTF criteria, the indicated evidence for automated percutaneous mechanical lumbar discectomy is limited for short- and long-term relief. Limitations: A paucity of randomized controlled trials in the literature describing automated percutaneous mechanical disc decompression. Conclusion: This systematic review shows limited evidence for automated percutaneous mechanical lumbar discectomy. Automated percutaneous mechanical lumbar discectomy may provide appropriate relief in properly selected patients with contained lumbar disc herniation. Key words: Intervertebral disc disease, chronic low back pain, mechanical disc decompression, automated percutaneous mechanical lumbar discectomy, internal disc disruption, radiculitis.

An Update of the Systematic Appraisal of the Accuracy and Utility of Lumbar Discography in Chronic Low Back Pain

Background: The intervertebral disc has been implicated as a major cause of chronic lumbar spinal pain based on clinical, basic science, and epidemiological research. There is, however, a lack of consensus regarding the diagnosis and treatment of intervertebral disc disorders. Based on controlled evaluations, lumbar intervertebral discs have been shown to be the source of chronic back pain without disc herniation in 26% to 39% of patients. Lumbar provocation discography, which includes disc stimulation and morphological evaluation, is often used to distinguish a painful disc from other potential sources of pain. Despite the extensive literature, intense debate continues about lumbar discography as a diagnostic tool. Study Design: A systematic review of the diagnostic accuracy of lumbar provocation and analgesic discography literature. Objective: To systematically assess and re-evaluate the diagnostic accuracy of lumbar discography. Methods: The available literature on lumbar discography was reviewed. A methodological quality assessment of included studies was performed using the Quality Appraisal of Reliability Studies (QAREL) checklist. Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were included in the analysis. However, studies scoring less than 50% are presented descriptively and critically analyzed. The level of evidence was classified as good, fair, and limited or poor based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to September 2012, and manual searches of the bibliographies of known primary and review articles. Results: Over 160 studies were considered for inclusion. Of these, 33 studies compared discography with other diagnostic tests, 30 studies assessed the diagnostic accuracy of discography, 22 studies assessed surgical outcomes for discogenic pain, and 3 studies assessed the prevalence of lumbar discogenic pain. The quality of the overall evidence supporting provocation discography based on the above studies appears to be fair. The prevalence of internal disc disruption is estimated to be 39% to 42%, whereas the prevalence of discogenic pain without assessing internal disc disruption is 26%. Conclusion: This systematic review illustrates that lumbar provocation discography performed according to the International Association for the Study of Pain (IASP) criteria may be a useful tool for evaluating chronic lumbar discogenic pain. Key words: Lumbar intervertebral disc, lumbar discography, provocation discography, analgesic discography, diagnostic accuracy

Lumbar Discogenic Pain: State-of-the-Art Review

To test the null hypotheses that: lumbar intervertebral discs cannot be a source of pain; discs are not a source of pain; painful lumbar discs cannot be diagnosed; and there is no pathology that causes discogenic pain. Philosophical essay and discourse with reference to the literature. Anatomic and physiologic evidence denies the proposition that disc cannot be a source of pain. In patients with back pain, discs can be source of pain. No studies have refuted the ability of disc stimulation to diagnose discogenic pain. Studies warn only that disc stimulation may have a false-positive rate of 10% or less. Internal disc disruption is the leading cause of discogenic pain. Discogenic pain correlates with altered morphology on computerized tomography scan, with changes on magnetic resonance imaging, and with internal biophysical features of the disc. The morphological and biophysical features of discogenic pain have been produced in biomechanics studies and in laboratory animals. All of the null hypotheses that have been raised against the concept of discogenic pain and its diagnosis have each been refuted by one or more studies. Although studies have raised concerns, none has sustained any null hypothesis. Discogenic pain can occur and can be diagnosed if strict operational criteria are used to reduce the likelihood of false-positive results.

Analysis of dispersion of lumbar interlaminar epidural injectates

Analysis of dispersion of lumbar interlaminar epidural injectates

Prospective Clinical Study on Natural History of Discogenic Low Back Pain at 4 Years of Follow-up

Background: To accurately assess the effect of any therapy for treating discogenic low back pain, the natural history of such pain should be known beforehand. However, until now, no pathological characteristic could be used to predict the disease course of low back pain. Objective: To better instruct the clinical treatment of discogenic low back pain, a prospective clinical study was performed to observe the natural history of the disease. Study Design: A prospective clinical study during a 4-year follow-up period. Setting: The study was performed at a spinal center in China. Methods: A total of 279 patients with chronic low back pain were included from June 2006 through October 2007. Using discography, 156 patients (56%) were diagnosed to have discogenic back pain. A 101-point numerical rating scale (NRS) was used to assess the back pain symptoms and the Oswestry Disability Index (ODI) was used to assess lumbar function. Results: Of the 156 patients, 131 (84%) completed the study at 4-year follow-up. At the end of follow-up, 17 patients (13.0%) had their low back pain symptoms alleviated and lumbar function improved; 10 patients (7.6%) were slightly improved; 16 patients (12.2%) had their symptoms aggravated; and 88 patients (67.2%) experienced the same pain and disability as before. Although the average NRS and ODI scores obtained during the 4-year follow-up study gradually decreased, statistical significances were found in such changes (P &lt; 0.05,and P &lt; 0.05, respectively); however, the improvement rates of both pain (7.6%) and disability (5.2%) were very low. Limitations: The shortcoming of this study is its relatively small sample size. Conclusion: The present study indicated that the natural history of discogenic low back pain was chronic but persistent, and that the pain and disability in most patients did not improve over time. Key words: Discogenic low back pain, chronic low back pain, lumbar discography, painful disc, black disc, disc degeneration, internal disc disruption, natural history, prognosis.

Multivariable Analyses of the Relationships Between Age, Gender, and Body Mass Index and the Source of Chronic Low Back Pain

To examine the combined relationships between age, gender, and body mass index (BMI) and the specific source of chronic low back pain. Retrospective chart review. University spine center. Charts from 378 cases from 358 consecutive patients were reviewed and 157 independent cases from 153 patients who underwent definitive diagnostic injections were analyzed. Discography, dual diagnostic facet joint blocks, sacroiliac joint injections, anesthetic interspinous ligaments/opposing spinous processes/posterior fusion hardware injections, percutaneous augmentation. Chronic low back pain source was the primary outcome variable. Predictor variables included age at initial presentation, gender, and BMI. Age, gender, and BMI were each significantly associated with the source of chronic low back pain, after controlling for the effects of each other. Increases in age were associated with significant decreases in the odds of internal disc disruption (IDD) vs facet joint pain (FJP), sacroiliac joint pain (SIJP), and other sources and decreases in the odds of FJP and SIJP vs other sources. Being female was associated with significant increases in the odds of SIJP vs IDD, FJP, and other sources. Increased BMI was associated with significant increases in the odds of FJP vs SIJP. These findings suggest a significant relationship among gender, age, and BMI and structural causes of chronic low back pain. Lumbar IDD is more prevalent in young males while FJP is more prevalent in females with increased BMI. Female gender and low BMI are associated with SIJP.