Larger animal models, such as porcine, have been validated as appropriate models of the human disc with respect to biomechanics and biochemistry. They are advantageous for research as the models are relatively straightforward to prepare and easily obtainable for research to perform surgical techniques. The intention of this study was to quantitatively analyze gene expression for collagen and proteoglycan components of the extracellular matrix and for collagenase (MMP-1) in porcine discs of varying ages (Newborn; 2-3weeks, Mature; 6-9 month, Older; 2-3 years). In this study, we observed that the cell number and GAG (glycosaminoglycan) formation dramatically decreased with aging. Also, gene expression in the annulus fibrosus (AF) and nucleus pulposus (NP) cells changed with aging. The level of MMP-1 mRNA increased with age and both type I, II collagens decreased with age. The level of aggrecan mRNA was highest in the mature group and decreased significantly with aging. In the mature group, MMP-1 expression was minimal compared to the newborn group. In AF cells, type II collagen was expressed at a high level in the mature group with a higher level of aggrecan, when aged NP showed a decrease in type II collagen. The model of IVD degeneration in the porcine disc shows many changes in gene expression with age that have been previously documented for human and may serve as a model for studying changes in IVD metabolism with age. We concluded that the porcine model is excellent to test hypotheses related to disc degeneration while permitting time-course study in biologically active systems.
Age Factors ; Aggrecans/genetics/metabolism ; Aging/genetics/*metabolism ; Animals ; Animals, Newborn ; Collagen Type I/genetics/metabolism ; Collagen Type II/genetics/metabolism ; Glycosaminoglycans/genetics/metabolism ; Humans ; Intervertebral Disk Degeneration/genetics/*metabolism ; Matrix Metalloproteinase 1/genetics/*metabolism ; *Models, Animal ; Reverse Transcriptase Polymerase Chain Reaction ; Spinal Cord/*metabolism/pathology ; Swine

BACKGROUND: The purposes of the present study are to evaluate the subsidence and nonunion that occurred after anterior cervical discectomy and fusion using a stand-alone intervertebral cage and to analyze the risk factors for the complications. METHODS: Thirty-eight patients (47 segments) who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage and an autologous cancellous iliac bone graft from June 2003 to August 2008 were enrolled in this study. The anterior and posterior segmental heights and the distance from the anterior edge of the upper vertebra to the anterior margin of the cage were measured on the plain radiographs. Subsidence was defined as > or = a 2 mm (minor) or 3 mm (major) decrease of the segmental height at the final follow-up compared to that measured at the immediate postoperative period. Nonunion was evaluated according to the instability being > or = 2 mm in the interspinous distance on the flexion-extension lateral radiographs. RESULTS: The anterior and posterior segmental heights decreased from the immediate postoperative period to the final follow-up at 1.33 +/- 1.46 mm and 0.81 +/- 1.27 mm, respectively. Subsidence > or = 2 mm and 3 mm were observed in 12 segments (25.5%) and 7 segments (14.9%), respectively. Among the expected risk factors for subsidence, a smaller anteroposterior (AP) diameter (14 mm vs. 12 mm) of cages (p = 0.034; odds ratio [OR], 0.017) and larger intraoperative distraction (p = 0.041; OR, 3.988) had a significantly higher risk of subsidence. Intervertebral nonunion was observed in 7 segments (7/47, 14.9%). Compared with the union group, the nonunion group had a significantly higher ratio of two-level fusion to one-level fusions (p = 0.001). CONCLUSIONS: Anterior cervical fusion using a stand-alone cage with a large AP diameter while preventing anterior intraoperative over-distraction will be helpful to prevent the subsidence of cages. Two-level cervical fusion might require more careful attention for avoiding nonunion.
Adult ; Aged ; Biocompatible Materials ; Cervical Vertebrae/pathology/radiography/*surgery ; Diskectomy ; Female ; Humans ; *Internal Fixators ; Intervertebral Disk Degeneration/*surgery ; Ketones ; Male ; Middle Aged ; *Postoperative Complications ; Prosthesis Failure ; Radiculopathy/surgery ; Regression Analysis ; Risk Factors ; Spinal Cord Diseases/surgery ; Spinal Fusion/*methods ; Treatment Outcome

PURPOSE: To evaluate the clinical outcomes of cantilever transforaminal lumbar interbody fusion (c-TLIF) for upper lumbar diseases. MATERIALS AND METHODS: Seventeen patients (11 males, 6 females; mean +/- SD age: 62 +/- 14 years) who underwent c-TLIF using kidney type spacers between 2002 and 2008 were retrospectively evaluated, at a mean follow-up of 44.1 +/- 12.3 months (2 year minimum). The primary diseases studied were disc herniation, ossification of posterior longitudinal ligament (OPLL), degenerative scoliosis, lumbar spinal canal stenosis, spondylolisthesis, and degeneration of adjacent disc after operation. Fusion areas were L1-L2 (5 patients), L2-L3 (9 patients), L1-L3 (1 patient), and L2-L4 (2 patients). Operation time, blood loss, complications, Japanese Orthopaedic Association (JOA) score for back pain, bone union, sagittal alignment change of fusion level, and degeneration of adjacent disc were evaluated. RESULTS: JOA score improved significantly after surgery, from 12 +/- 2 to 23 +/- 3 points (p < 0.01). We also observed significant improvement in sagittal alignment of the fusion levels, from - 1.0 +/- 7.4 to 5.2 +/- 6.1 degrees (p < 0.01). Bony fusion was obtained in all cases. One patient experienced a subcutaneous infection, which was cured by irrigation. At the final follow-up, three patients showed degenerative changes in adjacent discs, and one showed corrective loss of fusion level. CONCLUSION: c-TLIF is a safe procedure, providing satisfactory results for patients with upper lumbar degenerative diseases.
Adult ; Aged ; Back Pain/surgery ; Blood Loss, Surgical ; Female ; Follow-Up Studies ; Humans ; Intervertebral Disk Displacement/surgery ; Lumbar Vertebrae/*surgery ; Male ; Middle Aged ; Scoliosis/surgery ; Spinal Diseases/*surgery ; Spinal Fusion/adverse effects/*methods ; Spinal Stenosis/surgery ; Spondylolisthesis/surgery ; Time Factors ; Treatment Outcome

PURPOSE: The purpose of this study is to investigate the mechanism of cellular proliferation of electromagnetic field (EMF) on human intervertebral disc (IVD) cells. MATERIALS AND METHODS: Human IVD cells were cultured three-dimensionally in alginate beads. EMF was exposed to IVD cells with 650Omega, 1.8 millitesla magnetic flux density, 60 Hz sinusoidal wave. Cultures were divided into a control and EMF group. Cytotoxicity, DNA synthesis and proteoglycan synthesis were measured by MTT assay, [3H]-thymidine, and [35S]-sulfate incorporation. To detect phenotypical expression, reverse transcription-polymerase chain reactions (RT-PCR) were performed for aggrecan, collagen type I, and type II mRNA expression. To assess action mechanism of EMF, IVD cells were exposed to EMF with NG-Monomethyl-L-arginine (NMMA) and acetylsalicylic acid (ASA). RESULTS: There was no cytotoxicity in IVD cells with the EMF group in MTT assay. Cellular proliferation was observed in the EMF group (p < 0.05). There was no difference in newly synthesized proteoglycan normalized by DNA synthesis between the EMF group and the control. Cultures with EMF showed no significant change in the expression of aggrecan, type I, and type II collagen mRNA compared to the control group. Cultures with NMMA (blocker of nitric oxide) or ASA (blocker of prostaglandin E2) exposed to EMF demonstrated decreased DNA synthesis compared to control cultures without NMMA or ASA (p < 0.05). CONCLUSION: EMF stimulated DNA synthesis in human IVD cells while no significant effect on proteoglycan synthesis and chondrogenic phenotype expressions. DNA synthesis was partially mediated by nitric oxide and prostaglandin E2. EMF can be utilized to stimulate proliferation of IVD cells, which may provide efficient cell amplification in cell therapy to degenerative disc disease.
Adult ; Aspirin/pharmacology ; Cell Proliferation/*radiation effects ; Collagen/metabolism ; Dinoprostone/metabolism ; *Electromagnetic Fields ; Enzyme Inhibitors/pharmacology ; Female ; Humans ; Intervertebral Disk/*pathology/radiation effects ; Male ; Middle Aged ; Nitric Oxide/metabolism ; Tetrazolium Salts/pharmacology ; Thiazoles/pharmacology ; omega-N-Methylarginine/pharmacology

Forty canine patients with a presumptive diagnosis of the intervertebral disc herniation at the thoracolumbar region were imaged. A neurological examination was performed and all patients were classified under four grades by the examination. The degrees of attenuation of the herniated disc material were measured in Housefield units (HU) in each image. The ratio of the area to herniated disc material and the height to disc material were measured. The clinical grade was correlated with the area ratio of the herniated disc material to the spinal cord, but not correlated with the height ratio of that. In the patients with epidural hemorrhage at surgery, HUs of the herniated disc material was lower than those with no epidural hemorrhage at surgery. Non-contrast computed tomography scans of the spine can be useful in diagnosing acute intervertebral disc disease in chondrodystrophoid breeds, evaluating patient status and identifying concurrent epidural hemorrhage.
Animals ; Dog Diseases/*pathology/radiography ; Dogs ; Intervertebral Disk Displacement/radiography/*veterinary ; Lumbar Vertebrae/*pathology/radiography ; Retrospective Studies ; Thoracic Vertebrae/*pathology/radiography ; Tomography, X-Ray Computed/methods/standards/*veterinary

PURPOSE: We investigated types and prevalence of coexisting lesions found on whole spine sagittal T2-weighted images (WSST2I) acquired from magnetic resonance imaging (MRI) and evaluated their clinical significance in surgical degenerative spinal diseases. MATERIALS AND METHODS: Coexisting spinal lesions were investigated using WSST2I from 306 consecutive patients with surgical degenerative spinal diseases. Severity of coexisting lesions was classified into four grades (0-3). Lesions of grade 2 and 3 were defined as "meaningful coexisting spine lesions" (MCSL). Degenerative spinal diseases were classified into three pathologies: simple disc herniation, degenerative spinal stenosis, and ligament ossification disease. The relationships between MCSL, gender, age, and primary spine lesions were analyzed. RESULTS: MCSL were found in 95 patients: a prevalence of 31.1%. Five out of 95 MCSL were surgically managed. The most common types of MCSL were disc herniation with 13.1% prevalence, followed by degenerative stenosis (9.5%) and ligament ossification diseases (6.8%). Older patients (age > or = 40) showed a significantly higher prevalence of MCSL than younger patients. There was no significant difference between male and female patients. The prevalence of MCSL was significantly higher (52.4%) in ligament ossification diseases than in disc herniation or spinal stenosis. CONCLUSION: Degenerative spinal diseases showed a high prevalence of MCSL, especially in old ages and ligament ossification diseases. WSST2I is useful for diagnosing coexisting spinal diseases and to avoid missing a significant cord-compressing lesion.
Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Intervertebral Disk Displacement/diagnosis ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Prevalence ; Spinal Diseases/classification/*diagnosis ; Spinal Stenosis/diagnosis ; Young Adult

BACKGROUND: The authors analyzed inter- and intra-observer agreement with respect to interpretation of simple magnetic resonance T1- and T2-weighted axial and sagittal images for the diagnosis of lumbar lateral disc herniation, including foraminal and extraforaminal disc herniations. METHODS: Forty-two patients in whom lumbar lateral disc herniation was suspected or confirmed by simple magnetic resonance imaging at one institute between May 2003 and December 2004 were included. The magnetic resonance images consisting of T1- and T2-weighted axial and sagittal images, and these were reviewed blindly and independently by three orthopaedic spine surgeons in a random manner. The images were interpreted as positive or negative for lateral disc herniation on 2 different occasions 3 months apart. Results were analyzed using Cohen's kappa statistic, and strengths of agreements were determined using the Landis and Koch criteria. RESULTS: The kappa values for inter-observer agreement averaged 0.234 (0.282, 0.111, and 0.308 respectively) on the first occasion, and 0.166 (0.249, 0.111, and 0.137 respectively) on the second occasion, with an overall mean value of 0.200. Thus, the strength of agreement was only slight-to-fair according to the Landis and Koch criteria. Kappa values for intra-observer agreement averaged 0.479 (0.488, 0.491, and 0.459 respectively), indicating moderate agreement. CONCLUSIONS: The present study indicates that simple magnetic resonance imaging is not a reliable imaging modality for diagnosing lumbar lateral disc herniation. Another imaging study with improved diagnostic values should be developed to diagnose this pathologic finding.
Aged ; Aged, 80 and over ; Female ; Humans ; Intervertebral Disk Displacement/*pathology ; Lumbar Vertebrae/*pathology ; *Magnetic Resonance Imaging ; Male ; Middle Aged ; Observer Variation ; Single-Blind Method

PURPOSE: The authors investigated the effect of lumbar facet tropism (FT) on intervertebral disc degeneration (DD), facet joint degeneration (FJD), and segmental translational motion. MATERIALS AND METHODS: Using kinetic MRI (KMRI), lumbar FT, which was defined as a difference in symmetry of more than 7degrees between the orientations of the facet joints, was investigated in 900 functional spinal units (300 subjects) in flexion, neutral, and extension postures. Each segment at L3-L4, L4-L5, and L5-S1 was assessed based on the extent of DD (grade I-V) and FJD (grade 1-4). According to the presence of FT, they were classified into two groups; one with FT and one with facet symmetry. For each group, demographics, DD, FJD and translational segmental motion were compared. RESULTS: The incidence of FT was 34.5% at L3-L4, 35.1% at L4-L5, and 35.2% at L5-S1. Age and gender did not show any significant relationship with FT. Additionally, no correlation was observed between DD and FT. FT, however, wasfound to be associated with a higher incidence of highly degenerated facet joints at L4-L5 when compared to patients without FT (p < 0.01). Finally, FT was not observed to have any effects upon translational segmental motion. CONCLUSION: No significant correlation was observed between lumbar FT and DD or translational segmental motion. However, FT was shown to be associated significantly with the presence of high grades of FJD at L4-L5. This suggests that at active sites of segmental motion, FT may predispose to the development of facet joint degeneration.
Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Female ; Humans ; Intervertebral Disk Displacement/*etiology/pathology ; Joint Diseases/*complications/pathology ; Lumbar Vertebrae/*pathology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Sex Factors ; Zygapophyseal Joint/*pathology/physiopathology

Anterior cervical discectomy and fusion (ACDF) is currently the standard treatment for cervical disc disease. Some patients wish to be treated with a less invasive method, because of their social/physical situations. Here we present one method of treatments for socially/physically active patients. Three patients had triceps weakness and mild posterior neck pain. The offending lesions were at the C6-7 level. All were middle-aged soldiers with families. If conventional ACDF were performed, they would have to retire from the military according to the regulation. They had to be able to perform military drills after the treatment if they were going to be able to keep their jobs. Because of their social/physical situations, all wanted to choose method with that they could treat the disease and keep their jobs. For these reasons, the posterior cervical endoscopic discectomies were performed. Ruptured fragments were successfully removed in all. The arm pain improved by more than 90% in two patients by 7 days and in the other patient by 2 months, respectively (excellent outcome by Macnab's criteria). None of the operations caused instability. All of the patients are currently able to successfully perform their military drills without difficulty. The posterior cervical endoscopic discectomy may be a promising alternative for the physically/socially active patients.
Adult ; Cervical Vertebrae/radiography/*surgery ; *Diskectomy ; Endoscopy ; Humans ; Intervertebral Disk/radiography/surgery ; Magnetic Resonance Imaging ; Male ; Severity of Illness Index ; Tomography, X-Ray Computed ; Treatment Outcome

BACKGROUND: We retrospectively evaluated the clinical and radiological outcomes of posterior lumbar interbody fusion (PLIF) with using a unilateral single cage and a local morselized bone graft. METHODS: Fifty three patients who underwent PLIF with a unilateral single cage filled with local morselized bone graft were enrolled in this study. The average follow-up duration was 31.1 months. The clinical outcomes were evaluated with using the visual analogue scale (VAS) at the pre-operative period, at 1 year post-operation and at the last follow-up, the Oswestry Disability Index, the Prolo scale and the Kim & Kim criteria at the last follow-up; the radiological outcomes were evaluated according to the change of bone bridging, the radiolucency, the instablity and the disc height. RESULTS: For the clinical evaluation, the VAS pain index, the Oswestry Disability Index, the Prolo scale and the Kim & Kim criteria showed excellent outcomes. For the the radiological evaluation, 52 cases showed complete bone union at the last follow-up. Regarding the complications, only 1 patient had cage breakage during follow-up. CONCLUSIONS: PLIF using a unilateral single cage filled with a local morselized bone graft has the advantages of a shorter operation time, less blood loss and a shorter hospital stay, as compared with the PLIF using bilateral cages, for treating degenerative lumbar spine disease. This technique also provides excellent outcomes according to the clinical and radiological evaluation.
Adult ; Aged ; Blood Loss, Surgical ; Bone Transplantation/*methods ; Female ; Follow-Up Studies ; Humans ; Intervertebral Disk Degeneration/*radiography/*surgery ; Lumbar Vertebrae/pathology/*radiography/*surgery ; Male ; Middle Aged ; Prosthesis Implantation/methods ; Retrospective Studies ; Spinal Fusion/*methods ; Spinal Stenosis/surgery ; Spondylolisthesis/surgery ; Time and Motion Studies ; Treatment Outcome