Sadaaki Oki

Outcomes of surgical treatment for cervical myelopathy in patients more than 75 years of age.

STUDY DESIGN Retrospective study on the results of surgical treatment of compressive cervical myelopathy in patients more than 75 years of age. OBJECTIVES To investigate clinical features and surgical outcomes of compressive cervical myelopathy in aged patients and to discuss the role of surgical treatment. SUMMARY OF BACKGROUND DATA There are few data focused on the outcomes of surgery in patients with cervical myelopathy who are more than 75 years of age. METHODS Seventeen patients with compressive cervical myelopathy who underwent surgery were reviewed. The average age at the time of surgery was 77.2 years. Posterior decompression in 15 patients and anterior decompression in 2 patients were performed. Neurologic deficits before and after surgery were assessed using a scoring system proposed by the Japanese Orthopaedic Association (JOA score). Independence of daily living was evaluated. Radiologic features were examined with radiographs and magnetic resonance imaging. Clinical results were compared with those of patients less than 65 years old as a control. RESULTS The preoperative mean JOA score was 6.1, the postoperative maximum JOA scores averaged 11.4, and the recovery rate was 48.4%. These were significantly inferior to scores in those less than 65 years of age. All seven of the patients who could not walk even with aids before surgery became independent in daily activities after surgery. At the final follow-up, the mean JOA score had decreased to 10.7 and the recovery rate to 39.1%. Five of nine patients whose follow-up periods were more than 5 years showed decreases in JOA score, although all patients were still ambulatory. CONCLUSIONS Surgical decompression for cervical myelopathy appears to be beneficial, even in patients more than 75 years of age, in improving neurologic function and ability to engage in activities of daily living.

Morphologic Differences of the Vascular Buds in the Vertebral Endplate: Scanning Electron Microscopic Study

Study Design Vascular buds in rabbit vertebral endplates were examined by scanning electron microscopy of corrosion casts. Objectives To examine morphologic differences between vascular buds in two regions of the vertebral endplate (inner anular and nucleus pulposar). Summary of Background Data Vascular buds are specific structures present at the vertebral endplate that are important as nourishing channels. There is a significant difference in permeability between the lateral portion (inner anular) and the central portion (nucleus pulposar) of the endplate, the latter usually being permeable and the former being impermeable. Morphologic differences between vascular buds in the two regions have not been investigated previously. Methods Eight 20-week-old rabbits were used. Vascular buds in rabbit vertebral endplates were examined by scanning electron microscopy of corrosion casts. Results The vascular buds in the region of the inner anulus form simple loops, but those in the area near the nucleus pulposus exhibit swollen and complex coil-like loops. Although they differ structurally, the average number of vascular buds per area does not vary between the two regions. Conclusions We suggest that the morphologic difference between the vascular buds in the two regions (inner anular and nucleus pulposar) plays a principal role in permeability at the endplate.

Atlanto-occipital hypermobility in subjects with Down's syndrome

Study Design The upper cervical spines of 57 subjects with Downs syndrome were retrospectively examined, with special attention to atlanto-occipital mobility. Objective To examine the magnitude of atlanto-occipital mobility and its clinical significance in subjects with Downs syndrome. Summary of Background Data Atlanto-occipital translation of more than 1 mm in adults implies instability. However, the normal value in children with Downs syndrome has not been established, and the value In Downs syndrome has not been evaluated based on a comparison between subjects with Downs syndrome and control subjects. Methods Measurements were made by Wiesel and Rothmans method in 38 subjects with Downs syndrome and 34 control subjects. Results Atlanto-occipital translation in the Downs syndrome group ranged from 0–6.4 mm (mean, 2.3 mm), whereas in the control group it ranged from 0–2.1 mm (mean, 0.61 mm). The difference was statistically significant. Of the 38 subjects with Downs syndrome, 37 were asymptomatic. Conclusion The magnitude of atlanto-occipital translation, as expected, apparently was greater in subjects with Downs syndrome than in control subjects. Although the possibility of neurologic complications should be considered whenever unusually high atlanto-occipital mobility is seen, a majority of the subjects with Downs syndrome were asymptomatic.

Three-dimensional structure of the vascular network in normal and immobilized muscles of the rat☆☆☆

OBJECTIVE To examine whether there are three-dimensional changes in capillaries of rat soleus muscle during mechanical limb immobilization. DESIGN Scanning electron microscopy, with the microcorrosion cast technique, was used to examine vascular networks in immobilized Wistar rat soleus muscles from 4 to 12 weeks after limb immobilization and to compare these networks with those in the control muscle. INTERVENTION Immobilization of the soleus muscle was achieved by unilateral pinning of the ankle joint in full plantar flexion. RESULTS The wavelike structure of the vascular network in the control muscles changed into a straight configuration in 8- and 12-week immobilized muscles.

Age changes of neuromuscular junctions in the extensor digitorum longus muscle of spontaneous thymoma BUF/Mna rats

Abstract BUF/Mna rats spontaneously develop thymomas and cause muscle weakness of hind legs at an advanced age. This rat strain has been recognized as a suitable animal model for human myasthenia gravis or related myopathies. To characterize the structural changes of neuromuscular junctions (NMJs) in BUF/Mna rats, subneural apparatuses (SNAs) of extensor digitorum longus muscles of young-adult (4-month-old) and aged (22- to 25-month-old) male rats were examined using scanning and transmission electron microscopy. The SNAs of NMJs in young rats consist of complex labyrinthine gutters with numerous slit-like junctional folds. SNAs in aged BUF/Mna rats, however, are characterized by: (1) a group of cup-like depressions with very wide slit-like junctional folds in relatively large muscle fibers (the major type), (2) the presence of slit-like folds on the flat sarcoplasm outside the cup-like depressions or on the protruded sarcoplasm, and (3) winding gutters or a small number of round depressions with poorly developed synaptic folds in small and medium-sized muscle fibers (the minor type). Since similar structural changes have been reported in dystrophic mice or normally aged rats, it is suggested that both the slowly progressing muscle atrophy and age-dependent turnover of muscle fibers may occur in the aged BUF/Mna rats.