Reliable Magnetic Resonance Imaging Based Grading System for Cervical Intervertebral Disc Degeneration.

STUDY DESIGN: Observational. PURPOSE: To develop a simple and comprehensive grading system for cervical discs that precisely, consistently and meaningfully presents radiologic and morphologic data. OVERVIEW OF LITERATURE: The Thompson grading system is commonly used to classify the severity of degenerative lumbar discs on magnetic resonance imaging (MRI). Inherent differences in the morphological and physiological characteristics of cervical discs have hindered development of precise classification systems. Other grading systems have been developed for degenerating cervical discs, but their versatility and feasibility in the clinical setting is suboptimal. METHODS: MRIs of 46 human cervical discs were de-identified and displayed in PowerPoint format. Each slide depicted a single disc with a normal (grade 0) disc displayed in the top right corner for reference. The presentation was given to 25 physicians comprising attending spine surgeons, spine fellows, orthopaedic residents, and two attending musculoskeletal radiologists. The grading system included Grade 0 (normal height compared to C2-3, mid cleft still visible), grade 1 (dark disc, normal height), grade 2 (collapsed disc, few osteophytes), and grade 3 (collapsed disc, many osteophytes). The ease of use of the system was gauged in the participants and the interobserver reliability was calculated. RESULTS: The intraclass correlation coefficient for interobserver reliability was 0.87, and 0.94 for intraobserver reliability, indicating excellent reliability. Ninety-five percent and 85 percent of the clinicians judged the grading system to be clinically feasible and useful in daily practice, respectively. CONCLUSIONS: The grading system is easy to use, has excellent reliability, and can be used for precise and consistent clinician communication.

The effects of glucosamine sulfate on intervertebral disc annulus fibrosus cells in vitro.

BACKGROUND CONTEXT: Glucosamine has gained widespread use among patients, despite inconclusive efficacy data. Inconsistency in the clinical literature may be related to lack of understanding of the effects of glucosamine on the intervertebral disc, and therefore, improper patient selection. PURPOSE: The goal of our study was to investigate the effects of glucosamine on intervertebral disc cells in vitro under the physiological conditions of inflammation and mechanical loading. STUDY DESIGN: Controlled in vitro laboratory setting. METHODS: Intervertebral disc cells isolated from the rabbit annulus fibrosus were exposed to glucosamine sulfate in the presence and absence of interleukin-1ß and tensile strain. Outcome measures included gene expression, measurement of total glycosaminoglycans, new proteoglycan synthesis, prostaglandin E2 production, and matrix metalloproteinase activity. The study was funded by NIH/NCCAM, and the authors have no conflicts of interest. RESULTS: Under conditions of inflammatory stimulation alone, glucosamine demonstrated a dose-dependent effect in decreasing inflammatory and catabolic mediators and increasing anabolic genes. However, under conditions of mechanical stimulation, although inflammatory gene expression was decreased, PGE2 was not. In addition, matrix metalloproteinase-3 gene expression was increased and aggrecan expression decreased, both of which would have a detrimental effect on matrix homeostasis. Consistent with this, measurement of total glycosaminoglycans and new proteoglycan synthesis demonstrated detrimental effects of glucosamine under all conditions tested. CONCLUSIONS: These results may in part help to explain the conflicting reports of efficacy, as there is biological plausibility for a therapeutic effect under conditions of predominate inflammation but not under conditions where mechanical loading is present or in which matrix synthesis is needed.

Safety of thromboembolic chemoprophylaxis in spinal trauma patients requiring surgical stabilization.

STUDY DESIGN: Retrospective review. OBJECTIVE: To determine the incidence of thromboembolic events, bleeding complications such as epidural hematomas, and wound complications in patients with spinal trauma requiring surgical stabilization. SUMMARY OF BACKGROUND DATA: Literature addressing the safety and efficacy of chemoprophylactic agents in postoperative patients with spinal trauma is sparse. As a result, significant variability exists regarding administration of thromboembolic chemoprophylaxis in this population. The risk of bleeding complications is particularly concerning. METHODS: Patients with spinal trauma who underwent surgical stabilization in 2009 and 2010 at a single level 1 trauma center were retrospectively reviewed. Exclusion criteria included patients who underwent solely decompressive procedures, noninstrumented fusions, kyphoplasty, or had incomplete medical records. Patients who received chemoprophylaxis were compared with patients who did not. Demographical information and injury data were collected. Primary outcome measures were prevalence of thromboembolic events, epidural hematomas, and persistent wound drainage requiring irrigation and debridement. RESULTS: Two hundred twenty-seven of 373 patients were included (56 in the untreated group, 171 in the treated group). Eight patients in the untreated group (14.3%) and 12 patients in the treated group (7%) developed postoperative thromboembolism (P = 0.096). There was 1 pulmonary embolism in the untreated group (1.8%), and 4 pulmonary embolisms in the treated group (2.3%). Surgical irrigation and debridement for wound drainage was required for 1.8% of patients in the untreated group and for 5.3% of patients in the treated group. No epidural hematomas were noted in either group. The treated group had more spinal levels fused (P = 0.46), higher injury severity scores (0.001), and longer hospitalizations (0.018). Patients who developed postoperative thromboembolism had significantly higher body mass indexes (P = 0.01), injury severity scores (0.001), number of spinal levels fused (P = 0.004), incidence of neurological deficits (0.001), and longer hospitalizations (0.16) compared with those who did not. CONCLUSION: The use of chemoprophylaxis appears to be safe in at-risk patients in the immediate postoperative period after spinal trauma surgery. No epidural hematomas occurred, and the risk of wound drainage is small. Body mass index, injury severity score, presence of neurological deficits, and number of spinal levels fused should be considered when determining which patients should receive chemoprophylaxis after surgical stabilization.

Expression and regulation of metalloproteinases and their inhibitors in intervertebral disc aging and degeneration.

BACKGROUND CONTEXT: Destruction of extracellular matrix (ECM) leads to intervertebral disc degeneration (IDD), which underlies many spine-related disorders. Matrix metalloproteinases (MMPs), and disintegrins and metalloproteinases with thrombospondin motifs (ADAMTSs) are believed to be the major proteolytic enzymes responsible for ECM degradation in the intervertebral disc (IVD). PURPOSE: To summarize the current literature on gene expression and regulation of MMPs, ADAMTSs, and tissue inhibitors of metalloproteinases (TIMPs) in IVD aging and IDD. METHODS: A comprehensive literature review of gene expression of MMP, ADAMTS, and TIMP in human IDD and reported studies on regulatory factors controlling their expressions and activities in both human and animal model systems. RESULTS: Upregulation of specific MMPs (MMP-1, -2, -3, -7, -8, -10, and -13) and ADAMTS (ADAMTS-1, -4, and -15) were reported in human degenerated IVDs. However, it is still unclear from conflicting published studies whether the expression of ADAMTS-5, the predominant aggrecanase, is increased with IDD. Tissue inhibitors of metalloproteinase-3 is downregulated, whereas TIMP-1 is upregulated in human degenerated IVDs relative to nondegenerated IVDs. Numerous studies indicate that the expression levels of MMP and ADAMTS are modulated by a combination of many factors, including mechanical, inflammatory, and oxidative stress, some of which are mediated in part through the p38 mitogen-activated protein kinase pathway. Genetic predisposition also plays an important role in determining gene expression of MMP-1, -2, -3, and -9. CONCLUSIONS: Upregulation of MMP and ADAMTS expression and enzymatic activity is implicated in disc ECM destruction, leading to the development of IDD. Future IDD therapeutics depends on identifying specific MMPs and ADAMTSs whose dysregulation result in pathological proteolysis of disc ECM.

What is the prevalence of MRSA colonization in elective spine cases?

BACKGROUND: The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection is increasing. However, the prevalence of MRSA colonization among patients undergoing spine surgery is unclear. QUESTIONS/PURPOSES: We therefore (1) determined the prevalence of MRSA colonization in a population of patients scheduled for elective spine surgery; and (2) evaluated whether MRSA screening and treatment reduce the rate of early wound complications. METHODS: We retrospectively reviewed prospectively collected data from 1002 patients undergoing elective spine surgery in 2010. There were 719 primary and 283 revision surgeries. Instrumentation was used in 72.0% cases and autologous iliac crest bone graft was taken in 65.1%. Twelve patients were lost to followup; of the remaining 990 patients, 503 were screened for MRSA and 487 were not. MRSA-colonized patients were treated with mupirocin and chlorhexidine. An early wound complication was defined as wound drainage or the presence of an abscess. Patients were followed for a minimum of 3 months (average, 7 months; range, 3-545 days). RESULTS: Of the patients undergoing elective spine surgery and screened for MRSA, 14 of 503 (2.8%) were colonized with MRSA. The rates of early wound complications were similar for patients who were screened and pretreated for MRSA (17 of 503 [3.4%]) compared with those who were not (17 of 487 [3.5%]). CONCLUSIONS: The colonization rate for MRSA in our elective spine surgery population was comparable to that in the arthroplasty literature. LEVEL OF EVIDENCE: Level III, retrospective comparative study. See the Guidelines for Authors for a complete description of levels of evidence.

Identifying inflammatory targets for biologic therapies for spine pain.

The costs associated with treating spine-related conditions are enormous and are trending upward. Current methods employed to treat inflammatory-mediated pain are targeted at alleviating symptoms, rather than correcting the underlying cause of disease. It is clear that a biochemical basis for inflammatory-mediated intervertebral disk, facet joint, and nerve pain exists. Biologic therapies that address the underlying cause of pain could potentially decrease the costs associated with treating spine pathology. MMPs, IL-1, TNF- α, IL-6, NGF, bradykinin, prostaglandins, and nitric oxide are implicated in much of the catabolic effects seen in the pathogenesis of inflammatory-mediated pain and are good targets for inhibition. The anticatabolic and anabolic effects of TIMPs, BMPs, TGF- ß, and IGF-1 are targets already shown to favorably impact disk matrix homeostasis. With rapid advances in biomedical technology, these interventions may be available for clinical use in the near future.