Comparison of magnetic resonance imaging and computed tomogram-myelography for evaluation of cross sections of cervical spinal morphology.

STUDY DESIGN: Comparison of magnetic resonance imaging (MRI) and computed tomography-myelography (CTM) for cervical intracanalar dimensions. OBJECTIVE: To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the cervical spine. SUMMARY OF BACKGROUND DATA: The relative advantages and disadvantages of MRI and CTM in measuring cervical intracanalar dimensions are poorly understood. METHODS: MRI and CTM were used to measure cervical disc levels in 45 subjects with various cervical spinal diseases. Measurements included dural area, dural anteroposterior (A-P) diameter, dural right-left (RL) diameter, cord area, cord anteroposterior (A-P) diameter, cord right-left (RL) diameter and cerebrospinal fluid (CSF) space (anterior and posterior). Each section was graded by 2 orthopedic surgeons for degree of stenosis (Grades, 0-3), and the intra- and interobserver reproducibility of these measurements (intraclass correlation coefficients: ICC) was assessed. RESULTS: In both CTM and MRI, intra- and interobserver reproducibility (ICC) ranged from 0.702 to 0.989, suggesting that both imaging methods are reproducible. Importantly, CTM measurements of dural area, dural A-P diameter, dural RL diameter, and CSF space (anterior and posterior) were slightly, but significantly (P < 0.001), larger than MRI measurements. In contrast, MRI measurements of cord area, cord A-P diameter, and cord RL diameter were slightly, but significantly (P < 0.001), larger than CTM measurements. Degree of stenosis was significantly more severe in MRI than in CTM. CONCLUSION: Both CTM and MRI provided reproducible measurements of cervical intracanalar dimensions. Measurements of dura were slightly larger in CTM, whereas measurements of spinal cord were slightly larger in MRI, making stenosis more severe in MRI than in CTM. The clinical relevance of these slight differences requires further examination.

Hemilaminectomy for removal of extramedullary or extradural spinal cord tumors: medium to long-term clinical outcomes.

PURPOSE: Laminectomy is generally the treatment of choice for removal of spinal tumors. However, it has been shown that laminectomy may cause instability due to damage of posterior elements of the spinal column, which may induce subsequent kyphosis in the future. Therefore, to reduce the risk of deformity and spinal instability after laminectomy, hemilaminectomy has been used. However, the medium to long-term effects of hemilaminectomy on spinal sagittal alignment is not well understood. The present study was performed to evaluate the clinical outcomes, including spinal sagittal alignment of patients, associated with spinal cord tumors treated by surgical excision using hemilaminectomy. MATERIALS AND METHODS: Twenty hemilaminectomy operations at our institute for extramedullary or extradural spinal cord tumors in 19 patients were evaluated retrospectively with an average follow-up of 85 months (range, 40-131 months). Neurological condition was evaluated using the improvement ratio of the Japanese Orthopaedic Association Score (JOA score) for cervical, thoracic myelopathy, or back pain, and sagittal alignment by sagittal Cobb angle of the hemilaminectomied area. RESULTS: The mean improvement ratio of neurological results was 56.7% in the cervical spine (p < 0.01, n = 10), 26.3% in the thoracic spine (not significant, n = 5), and 48.6% in the lumbar spine (NS, n = 5). The sagittal Cobb angle was 4.3 ± 18.0° in the preoperative period and 5.4 ± 17.6° at the latest follow-up, indicating no significant deterioration. CONCLUSION: Hemilaminectomy is useful for extramedullary or extradural spinal cord tumors in providing fair neurological status and restoration of spinal sagittal alignment in medium to long-term follow-up.

Comparison of magnetic resonance imaging and computed tomography-myelography for quantitative evaluation of lumbar intracanalar cross-section.

PURPOSE: A comparison of MRI and computed tomography-myelography (CTM) for lumbar intracanalar dimensions. To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the lumbar spine. MATERIALS AND METHODS: MRI and CTM of lumbar disc levels from 61 subjects with various lumbar spinal diseases were studied. Dural area, dural anteroposterior (AP) diameter, dural right-left diameter, and thickness of the ligamentum flavum were measured by two orthopedic surgeons. Each section was graded by degree of stenosis. Absolute value and intra- and inter-observer correlation coefficients (ICC) of these measurements and the associations between MRI and CTM values were determined. RESULTS: Except for MRI determination of ligament flavum thickness, CTM and MRI and intra- and ICC suggested sufficient reproducibility. When measurements of dural area, dural AP diameter, and RL diameter were compared, values in CTM were significantly (p = 0.01-0.004) larger than those in MRI (CTM/MRI ratios, 119%, 111%, and 105%, respectively). As spinal stenosis became more severe, discrepancies between CTM and MRI in measurements of the dural sac became larger. CONCLUSION: Both CTM and MRI provided reproducible measurements of lumbar intracanalar dimensions. However, flavum thickness may be more accurately measured by CTM. Because the differences in the measurements between CTM and MRI are very slight and there is very little data to suggest that the precise degree of stenosis is related to symptoms or treatment outcome, the usefulness of the CTM over MRI needs to be confirmed in future studies.

Treatment of trochanteric fractures with the PFNA (proximal femoral nail antirotation) nail system - report of early results.

Currently, intramedullary devices are widely used for the treatment of trochanteric femoral fractures. A new device designed by AO/ASIF, the PFNA (proximal femoral nail antirotation), represents a unique intramedullary nail system for improved management, particularly in the elderly. The aim of the present study was to analyze the results of treatment with PFNA in 50 patients with trochanteric fractures. The operating time, intraoperative blood loss, and intraoperative and postoperative complications were recorded. The length of the surgical procedure averaged 20.3 min, and intraoperative blood loss averaged 22.8 mL. Reoperation was necessary in two patients (4%). We conclude that the PFNA nail is as effective as other implants in the treatment of trochanteric fractures.

Successful joint arthroplasty after treatment of destructive MRSA arthritis of the knee using antibiotic-loaded hydroxyapatite blocks: a case report.

Methicillin-resistant Staphylococcus aureus (MRSA) septic arthritis is frequently associated with a poor clinical outcome. Joint reconstruction may be worth attempting in patients with a history of persistent MRSA infection. Here we report an unusual case of MRSA septic arthritis of the knee joint that was treated successfully by joint replacement after initial placement of antibiotic-loaded hydroxyapatite (HA) blocks.

Reliabilities of and correlations among five standard methods of assessing the sagittal alignment of the cervical spine.

STUDY DESIGN: The reliabilities of and correlations among 5 standard methods of assessing cervical sagittal alignment were evaluated. OBJECTIVE: To investigate the reliabilities of and correlations among 5 standard methods of assessing cervical sagittal alignment. SUMMARY OF BACKGROUND DATA: Although various cervical sagittal alignment assessment methods are widely used, their relative reliability and intercorrelation have not been reported. METHODS: From 442 lateral cervical radiographs, 40 with lordotic, 40 with straight or sigmoid, and 40 with kyphotic alignment were selected. Two orthopedic surgeons independently evaluated the sagittal alignment in each group twice using CCL, C1-C7 Cobb, C2-C7 Cobb, sagittal tangent, and the Ishihara methods. Intraobserver and interobserver reliabilities were confirmed and the correlations among the 5 methods were measured. RESULTS: Intraobserver and interobserver reliabilities for all 5 methods were good. In the lordotic group, the correlations among all 5 methods were consistently strong (r = 0.731 to 0.922). In the straight or sigmoid group, the correlations were weak to moderate among the CCL, C2-C7 Cobb, sagittal tangent, and Ishihara methods but tended to be weak between these 4 methods and the C1-C7 Cobb method (r = -0.245 to 0.777). In the kyphotic group, the correlations were also weak to moderate among the same 4 methods, and were statistically insignificant between them and the C1-C7 Cobb. CONCLUSIONS: The correlations among the CCL, C1-C7 Cobb, C2-C7 Cobb, sagittal tangent, and Ishihara methods are strong when lordosis is retained; otherwise, they are moderate to poor. In the kyphotic group, C1-C7 Cobb has no significant correlation with the other 4 methods.