Object The authors analyzed a series of 118 cases of spinal dumbbell tumors to elucidate the feature of the tumors. Methods Of 674 cases of spinal cord tumors, the incidence of dumbbell tumors was studied. The tumors were analyzed, and the authors focus on the distribution of age and sex, the pathological diagnoses, their locations, Eden classification, and the surgical methods used. Results The incidence of dumbbell tumors was 18%. The mean patient age was 43 years, which was younger than that for all spinal cord tumors (mean 50 years). There were 11 patients younger than 10 years of age. The rate of dumbbell tumors in the cervical spine was significantly higher than that of all spinal cord tumors. Fifteen (18%) of the 81 schwannomas were observed in the C-2 nerve root, thus having a higher incidence than those in the other nerve roots. In 99 cases (84%), the tumors were removed through a hemilaminectomy with or without a facetectomy and posterior fusion. Of 118 cases, 69% of the tumors were schwannomas, and malignant tumors were found in 10 cases (8.5%). Seven (64%) of 11 patients younger than 10 years of age had malignant tumors. Three patients older than 10 years of age had malignant tumors, thus accounting for 2.8% of the 107 older patients. Conclusions The incidence of dumbbell tumors was 18%, and they are not uncommon. Malignant dumbbell tumors were more common in children younger than 10 years of age than in older patients.

No abstract

E., NISHIHIRA T. and KOKUBUN, S. Thoracic Myelopathy in Japan: Epidemiological Retrospective Study in Miyagi Prefecture during 15Years. Tohoku J. Exp. Med., 210 (3),[199][200][201][202][203][204][205][206][207][208] Thoracic myelopathy is defined as spinal cord compression in the thoracic region, leading to sensory and motor dysfunctions in the trunk and lower extremities, and can be caused by various degenerative processes of the spine. Thoracic myelopathy is rare, and there are many unsolved problems including its epidemiological and clinical features. We have established a registration system of spinal surgeries, which covered almost all surgeries in Miyagi Prefecture, and enrolled the data of 265 patients with thoracic myelopathy from 1988 to 2002. The annual rate of surgery gradually increased and averaged 0.9 per 100,000 inhabitants, which was less than 1/10 of that for cervical myelopathy. About 20 patients with thoracic myelopathy are operated on in Miyagi Prefecture each year. It frequently develops in middle-aged males. About half of the cases were caused by ossification of the ligamentum flavum, followed by ossification of the posterior longitudinal ligament, intervertebral disc herniation and posterior spur. Patients usually noticed numbness or pain in the legs and the preoperative duration was long, averaging 2 years. Its symptomatic similarities to lumbar disorders might cause difficulty in making a correct diagnosis. Since thoracic myelopathy can markedly restrict the activities of daily life, even general physicians should recognize this entity. thoracic myelopathy; epidemiological study; ossification of the ligamentum flavum; ossification of the posterior longitudinal ligament

Spinal disorders affect mainly older people and cause pain, paralysis and/or deformities of the trunk and/or extremities, which could eventually disturb locomotive functions. For ensuring safe and high-quality treatment of spinal disorders, in 1987, the Tohoku University Spine Society (TUSS) was established by orthopedic departments in Tohoku University School of Medicine and its affiliated hospitals in and around Miyagi Prefecture. All spine surgeries have been enrolled in the TUSS Spine Registry since 1988. Using the data from this registration system between 1988 and 2012, we demonstrate here the longitudinal changes in surgical trends for spinal disorders in Japan that has rushed into the most advanced "aging society" in the world. In total, data on 56,744 surgeries were retrieved. The number of spinal surgeries has annually increased approximately 4-fold. There was a particular increase among patients aged ≥ 70 years and those aged ≥ 80 years, with a 20-to 90-fold increase. Nearly 90% of the spinal operations were performed for degenerative disorders, with their number increasing approximately 5-fold from 705 to 3,448. The most common disease for surgery was lumbar spinal stenosis (LSS) (35.9%), followed by lumbar disc herniation (27.7%) and cervical myelopathy (19.8%). In 2012, approximately half of the patients with LSS and cervical myelopathy were ≥ 70 years of age. In conclusion, the number of spinal operations markedly increased during the 25-year period, particularly among older patients. As Japan has a notably aged population, the present study could provide a near-future model for countries with aging population.

Thermal expansion behavior in a stoichiometric AuCu alloy was investigated from the viewpoint of a phase transition. Thermal expansion measurements were conducted from room temperature to 873 K at various heating and cooling rates. The crystal structures and phase transitions were analyzed by X-ray diffractometry and differential scanning calorimetry, respectively. The cast sample showed a disordered face-centered cubic (fcc) structure, which changed into a face-centered tetragonal structure AuCu I or mixed structure of fcc and AuCu I after thermal expansion measurement. In the thermal expansion curves, the break points corresponded to order-disorder transition. During the heating process, three break points corresponding to three different ordering stages were observed. The activation energy for each stage was obtained using the Kissinger method. It is believed that the first and second stages are ascribable to the migration of excess vacancies induced by quenching, and that the third is predominantly due to self-diffusion. [