Posterior Fixation of a Cervical Fracture Using the RRS Loop Spine System and Polyethylene Tape in an Elderly Ankylosing Spondylitis Patient: A Case Report.

An 80-year-old woman presented with neck pain and paraparesis of Frankel C in her upper and lower extremities after falling. Imaging revealed an ankylosing cervical spine and a fracture line running obliquely from the anterior C3-4 to the posterior C4-5 level. Posterior fixation from the occi pit to T3 was performed using the RRS Loop Spine System and concomitant polyethylene tape fixation. This system is characterized by the uniqueness of how it screws to the occi pit and its use of a fixation rod with a larger diameter than in other instrumentation devices for use in the cervical region. Sublaminar banding using polyethylene tape was used to secure fixation. Her postoperative course was unremarkable, and her neck pain was relieved, although neurological improvement was minor. To our knowledge, this is the first report of an application of the RRS Loop Spine System to an ankylosing spondylitis patient with a cervical fracture.

Assessment of pure single nerve root resection in the treatment of spinal schwannoma: focus on solitary spinal schwannomas located below the thoracolumbar junction.

BACKGROUND: The incidence of neurological deficits is reportedly low after sacrificing the affected nerve root during spinal schwannoma treatment. Although the incidence has been widely reported, the operative method for nerve root resection has been not clarified. To evaluate the safety of pure nerve root resection, we focused on solitary spinal schwannomas below the thoracolumbar level and investigated the effect of affected nerve resection. METHODS: Twenty-three spinal schwannoma patients were retrospectively examined. The mean age at surgery was 53 years. We investigated preoperative symptoms, duration of the disorder, postoperative neurological deficits, and clinical outcomes. In addition, we measured tumor size on computed tomography after myelography or on magnetic resonance images using image-analysis software. We retrospectively assessed correlations among duration of symptoms, tumor size, and postoperative neurological deficits. RESULTS: The tumors comprised 19 intradural schwannomas and 4 dumbbell-shaped schwannomas. No postoperative neurological deficits were observed in the intradural schwannoma patients. In contrast, three of the four dumbbell-shaped schwannoma patients experienced postoperative neurological deficits. Among these three patients, two recovered quickly whereas one never recovered. The mean duration of the disorder was 29 months. The postoperative modified JOA score (13.0) was significantly improved compared with the preoperative score (8.9). The mean maximum tumor sizes were 97.2 mm(2) for the intradural schwannomas and 884.0 mm(2) for the dumbbell-shaped schwannomas. There were no correlations among tumor size, duration of the disorder, and postoperative neurological deficits. CONCLUSIONS: On the basis of this study, we recommend pure single nerve resection for treatment of intradural spinal schwannomas before such tumors progress and involve other normal roots, because postoperative neurological deficits did not occur in our intradural schwannoma patients, irrespective of tumor size, when this procedure was used. However, dumbbell-shaped schwannoma patients should be carefully treated operatively, because high incidence of postoperative neurological deficits can be expected.

Degenerative spondylolisthesis does not influence surgical results of laminoplasty in elderly cervical spondylotic myelopathy patients.

The objective of the study was to investigate the comorbidity of degenerative spondylolisthesis (DS), in elderly cervical spondylotic myelopathy (CSM) patients in our hospital, and the correlation between surgical results and preoperative DS. There are few studies on the outcome of laminoplasty for CSM with DS. A total of 49 elderly patients (>65 years old) who eventually had surgical treatment for CSM were evaluated. A slippage displacement of more than 2.5 mm at least at one level was classified to have a positive DS on flexion/extension radiographs (DS group). A slippage displacement less than 1.0 mm was considered a negative DS (non-DS group). Seventeen patients who had slippage of 1.0-2.5 mm were excluded from the study. The DS group (n = 15) included cases with DS at preoperation, while the remaining cases (n = 17) belonged to the non-DS group. The flexion/extension radiographs of the two groups were compared for range of motion and clinical results at 3 years after the operation. Of all elderly patients, 30.6% had DS. There was no significant difference between the two groups based on the clinical results. The range of motion of all cervical spines (DS group and non-DS group) was significantly limited. However, there was no significant difference between the two groups. New postoperative DS appeared in four patients, of which two were from the DS group and two from the non-DS group. These data suggest that degenerative spondylolisthesis does not influence surgical results in elderly cervical spondylotic myelopathy patients.

Temporal changes in the tensile strength of ultra-high-molecular-weight polyethylene cable embedded in muscle tissue.

BACKGROUND: Wires and cables have been used extensively for spinal sublaminar wiring, but damages to the spinal cord due to compression by metal wires have been reported. We have used more flexible ultra-high-molecular-weight polyethylene cable (Tekmilon tape) instead of metal wires since 1999 and have obtained good clinical outcomes. Although the initial strength of Tekmilon tape is equivalent to metal wires, the temporal changes in the strength of Tekmilon tape in the body should be investigated to show that sufficient strength is maintained over time until bone union is complete. METHODS: Tekmilon tape was embedded into the paravertebral muscle of 10-week-old male Japanese white rabbits. Samples were embedded for 0, 1, 3, 6 or 12 months. At the end of each period, sequential straight tensile strength and sequential knot-pull tensile strength were measured. FINDINGS: The initial strength of Tekmilon tape in muscle tissue was maintained over time, with 92% straight tensile strength and 104% knot-pull tensile strength at 6months, and values of 77% and 100% at 12 months, respectively. Since single knot is clinically relevant, it is very important that the knot-pull tensile strength did not decrease over a 12-month period. This suggests that temporal changes in the tensile strength of Tekmilon tape are negligible at 1 year. INTERPRETATION: Tekmilon tape maintains sufficient strength in vivo until bone union has occurred. It is useful for sublaminar wiring instead of metal materials due to its flexibility and strength and may reduce the risk of neurological damage.

Raloxifene: its ossification-promoting effect on female mesenchymal stem cells.

BACKGROUND: Raloxifene acts like estrogen in preventing bone loss in postmenopausal women, but it selectively activates biological responses in bone tissue. It has a direct effect on osteoblasts' differentiation and bone formation in bone marrow culture. However, the point at which raloxifene has an effect on bone marrow-derived mesenchymal stem cells (MSCs), regardless of sex difference, is not known. The purpose of this study was to examine the osteogenic effect of raloxifene on MSCs derived from female and male rats and to assess the sex difference of raloxifene with or without osteogenic supplements (OSs) in the regulation of bone formation. METHODS: Female and male rat bone marrow cells were cultured with or without OSs. In each experimental group, 10-6 M or 10-8 M raloxifene was added. As a control, cells were cultured without raloxifene. Histologically, mineralization was assessed by alizarin red S staining. Biochemically, alkaline phosphatase (ALP) activity, calcium content, and osteocalcin content were assessed. RESULTS: On histological analysis, mineralized nodules were seen on alizarin red S staining in the groups treated with OS. On the biochemical analysis, OS increased ALP activity, calcium content, and osteocalcin content. Among female groups with OSs, 10-6 M raloxifene significantly increased ALP activity, calcium content, and osteocalcin content compared with the controls. Among male groups, raloxifene had negligible effects. CONCLUSIONS: 10-6 M Raloxifene had no ossification-inducing effect on female MSCs, but it had an ossification-promoting effect; it had no osteogenic effect on male MSCs. Therefore, raloxifene has a sex difference with regard to its osteogenic effect on MSCs. Moreover, combined treatment with raloxifene plus OS has an effect on female MSCs. These results provide a useful insight into the possible influence of raloxifene after MSC transplantation in clinical practice.

Does developmental canal stenosis influence surgical results of bilateral open-door laminoplasty for cervical spondylotic myelopathy?

OBJECT: The purpose of this study was to investigate the prevalence of developmental canal stenosis in patients with cervical spondylotic myelopathy (CSM), and the correlation between surgical results and degree of developmental canal stenosis. METHODS: A total of 112 patients who eventually had surgical treatment for CSM were evaluated. Male patients whose sagittal spinal diameter was < 14 mm and females whose sagittal diameter was < 13 mm even at one level were classified as having developmental canal stenosis. Two groups of patients were used in this study; the "positive" group (57 cases) included patients with developmental canal stenosis preoperatively, whereas the "negative" group (55 cases) excluded such patients. Lateral functional radiographs obtained in patients in the 2 groups were compared for range of motion and clinical results. RESULTS: Developmental canal stenosis was found in 50.9% of all cases. Based on clinical results, there was no significant difference between the 2 groups. CONCLUSIONS: Patients with CSM showed a high incidence of preoperative developmental canal stenosis. However, there were no significant differences in clinical results between patients with and without this disorder. These results indicate that developmental canal stenosis is not a factor that influences surgical results.