OBJECTIVE: We report magnetic resonance imaging (MRI) findings on focal anterior displacement of the thoracic spinal cord in asymptomatic patients without a spinal cord herniation or intradural mass. MATERIALS AND METHODS: We identified 12 patients (male:female = 6:6; mean age, 51.7; range, 15-83 years) between 2007 and 2011, with focal anterior displacement of the spinal cord and without evidence of an intradural mass or spinal cord herniation. Two radiologists retrospectively reviewed the MRI findings in consensus. RESULTS: An asymmetric spinal cord deformity with a focal dented appearance was seen on the posterior surface of the spinal cord in all patients, and it involved a length of 1 or 2 vertebral segments in the upper thoracic spine (thoracic vertebrae 1-6). Moreover, a focal widening of the posterior subarachnoid space was also observed in all cases. None of the patients had myelopathy symptoms, and they showed no focal T2-hyperintensity in the spinal cord with the exception of one patient. In addition, cerebrospinal fluid (CSF) flow artifacts were seen in the posterior subarachnoid space of the affected spinal cord level. Computed tomography myelography revealed preserved CSF flow in the two available patients. CONCLUSION: Focal anterior spinal cord indentation can be found in the upper thoracic level of asymptomatic patients without a spinal cord herniation or intradural mass.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cerebrospinal Fluid/physiology ; Female ; Hernia/pathology ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Retrospective Studies ; Spinal Cord Diseases/pathology/*radiography/surgery ; Spine/pathology/radiography ; Thoracic Vertebrae/pathology/*radiography ; Tomography, X-Ray Computed ; Young Adult

BACKGROUNDOssification of the ligamentum flavum (OLF) is being increasingly recognized as a cause of thoracic myelopathy. This study was to describe a rare clinical entity of spinal cord kinking (SK) in thoracic myelopathy secondary to OLF.

METHODSThe data of 95 patients with thoracic myelopathy secondary to OLF were analyzed retrospectively. The incidence and location of SK were determined using preoperative magnetic resonance imaging (MRI). The clinical presentation and radiological characteristics in patients with SK were analyzed. Posterior en bloc laminectomy with OLF was performed, and the surgical results were evaluated.

RESULTSSK was found in seven patients (7.4%) based on preoperative MRI. The patients included one male and six females with an average age of 55.6 years (range, 48-64 years). Five patients presented with radiculomyelopathy and two presented with typical thoracic myelopathy of spastic paraparesis. In all cases, the kinking was located just above the end of the spinal cord where the conus medullaris (CM) was compressed by the OLF. The degree of SK varied from mild to severe. The tip of the CM was located between the upper third of T11 to the lower third of L1, above the lower edge of L1. With an average follow-up of 30.4 months, the modified Japanese Orthopedic Association score significantly improved from 5.7 ± 1.8 preoperatively to 8.9 ± 1.4 postoperatively (t = 12.05; P < 0.0001) with an improvement rate of 63.1 ± 12.3%.

CONCLUSIONSSK is a rare radiological phenomenon. It is typically located at the thoracolumbar junction, where the CM is compressed by the OLF. Our findings indicate that these patients may benefit from a posterior decompressive procedure.

Female ; Humans ; Ligamentum Flavum ; pathology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Ossification, Heterotopic ; complications ; Radiography ; Spinal Cord Compression ; diagnosis ; diagnostic imaging ; surgery ; Spinal Cord Diseases ; diagnosis ; diagnostic imaging ; etiology ; surgery

Fatal Outcome ; Humans ; Magnetic Resonance Imaging ; Male ; Mediastinal Neoplasms ; complications ; diagnostic imaging ; pathology ; surgery ; Mediastinum ; diagnostic imaging ; pathology ; Neuroectodermal Tumors, Primitive, Peripheral ; complications ; diagnostic imaging ; pathology ; surgery ; Radiography ; Spinal Cord Diseases ; diagnostic imaging ; etiology ; pathology ; Young Adult

BACKGROUND: To evaluate the clinical efficacy of three-level anterior cervical arthrodesis with polyethyletherketone (PEEK) cages and plate fixation for aged and osteoporotic patients with degenerative cervical spinal disorders. METHODS: Twenty one patients, who had undergone three-level anterior cervical arthrodesis with a cage and plate construct for degenerative cervical spinal disorder from November 2001 to April 2007 and were followed up for at least two years, were enrolled in this study. The mean age was 71.7 years and the mean T-score using the bone mineral density was -2.8 SD. The fusion rate, change in cervical lordosis, adjacent segment degeneration were analyzed by plain radiographs and computed tomography, and the complications were assessed by the medical records. The clinical outcomes were analyzed using the SF-36 physical composite score (PCS) and neck disability index (NDI). RESULTS: Radiological fusion was observed at a mean of 12.3 weeks (range, 10 to 15 weeks) after surgery. The average angle of cervical lordosis was 5degrees preoperatively, 17.6degrees postoperatively and 16.5degrees at the last follow-up. Degenerative changes in the adjacent segments occurred in 3 patients (14.3%), but revision surgery was unnecessary. In terms of instrument-related complications, there was cage subsidence in 5 patients (23.8%) with an average of 2.8 mm, and loosening of the plate and screw occurred in 3 patients (14.3%) but there were no clinical problems. The SF-36 PCS before surgery, second postoperative week and at the last follow-up was 29.5, 43.1, and 66.2, respectively. The respective NDI was 55.3, 24.6, and 15.9. CONCLUSIONS: For aged and osteoporotic patients with degenerative cervical spinal disorders, three-level anterior cervical arthrodesis with PEEK cages and plate fixation reduced the pseudarthrosis and adjacent segment degeneration and improved the clinical outcomes. This method is considered to be a relatively safe and effective treatment modality.
Aged ; Aged, 80 and over ; Biocompatible Materials ; *Bone Plates/adverse effects ; Bone Screws/adverse effects ; Cervical Vertebrae/radiography/*surgery ; Diskectomy ; Female ; Follow-Up Studies ; Humans ; Ketones ; Lordosis/pathology ; Male ; Radiculopathy/surgery ; Severity of Illness Index ; Spinal Cord Diseases/surgery ; Spinal Diseases/*surgery ; Spinal Fusion/adverse effects/*methods ; Treatment Outcome

BACKGROUND: This study was designed to reevaluate the effectiveness of the Pavlov ratio in patients with cervical myelopathy. METHODS: We studied 107 patients who underwent open door laminoplasty for the treatment of cervical myelopathy between the C3 to C7 levels. We determined the Pavlov ratio on preoperative and postoperative cervical spine lateral radiographs, the vertebral body-to-canal ratio on sagittal reconstruction CT scans, and the vertebral body-to-cerebrospinal fluid (CSF) column ratio on T2-weighted sagittal MR images from C3 to C6. The severity of myelopathy was determined using the JOA score on both preoperative and postoperative images. The recovery rate was also calculated. The Pavlov ratio in plain radiographs from patients with myelopathy was compared with the ratio of the vertebral body to the spinal canal on CT and MRI. RESULTS: The average Pavlov ratio between C3 and C6 ranged from 0.71 to 0.76. On CT scan, the average vertebral body-to-canal ratio between C3 and C6 ranged from 0.62 to 0.66. On MRI, the vertebral body-to-CSF column ratio between C3 and C6 ranged between 0.53 and 0.57. A positive correlation was noted between the Pavlov ratio and the vertebral body-to-canal ratio on sagittal-reconstruction CT (correlation coefficient = 0.497-0.627, p = 0.000) and between the Pavlov ratio and the vertebral body-to-CSF column ratio on MRI (correlation coefficient = 0.511-0.649, p = 0.000). CONCLUSIONS: We demonstrated a good correlation between the Pavlov ratio and both the vertebral body-to-canal ratio on CT and the vertebral body-to-CSF column ratio on MRI. Therefore, the Pavlov ratio can be relied upon to predict narrowing of the cervical spinal canal in the sagittal plane.
Adult ; Aged ; Aged, 80 and over ; Cerebrospinal Fluid ; Cervical Vertebrae/*pathology/*radiography/surgery ; Female ; Humans ; *Magnetic Resonance Imaging ; Male ; Middle Aged ; Observer Variation ; Predictive Value of Tests ; Reference Values ; Retrospective Studies ; Spinal Canal/radiography ; Spinal Cord Diseases/*pathology/*radiography ; *Tomography, X-Ray Computed

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