Bizarre parosteal osteochondromatous proliferation (Nora's lesion) of the foot.

A 22-year-old man presented with a growing lump on the fifth metatarsal of the right foot. Radiographically, the lesion was a calcified mass stuck on to the bone. The T2-weighted magnetic resonance images showed heterogeneity in intensity. A tumor was suspected and an excisional biopsy was done. The lesion was composed of a cartilaginous cap and bone tissue. Histological examination revealed characteristic features of bizarre parosteal osteochondromatous proliferation (BPOP), such as hypercellularity, a blue tinctorial quality in the osteocartilaginous interfaces, and a scattering of binucleated or bizarre enlarged chondrocytes. Immunohistochemically, basic fibroblast growth factor was expressed in nearly all chondrocytes within the cartilaginous cap, while vascular endothelial growth factor was expressed only in enlarged chondrocytes near the osteocartilaginous interfaces. Reverse transcription-polymerase chain reaction detected chondromodulin-I transcripts in the tissue of the cartilaginous cap. These findings indicate that the processes occurring in BPOP are similar to those occurring in endochondral ossification in the growth plate, and they support the concept that BPOP is a reparative process. BPOP is a rare tumorous lesion of the bone and is occasionally confused with other benign or malignant conditions. Thus, it is important to consider the clinical, radiographical and the gross histological features of the lesion when making a diagnosis.

Curvature and range of motion of the cervical spine after laminaplasty.

BACKGROUND: The curvature and range of motion of the cervical spine decrease after laminaplasty. However, to our knowledge these changes have not been studied prospectively. Also, the effect of laminaplasty on the mobility of the occipito-atlanto-axial joints has not been studied in detail. The purpose of our study was to prospectively evaluate the range of motion and curvature of the cervical spine, including the occipito-atlanto-axial joints, following laminaplasty. METHODS: We conducted a prospective study of twenty-six patients who underwent cervical laminaplasty. They were followed for a mean of 6.7 years (range, five to nine years). Radiographs were made before the operation and at one, three, and five years after the operation. The curvature index, the angle of each vertebra in the neutral position from the occiput to the seventh cervical vertebra, and the range of motion in the sagittal plane were measured. RESULTS: The curvature index, the angle of the axis and the sixth cervical vertebra, and the angle of the axis and the seventh cervical vertebra in the neutral position were reduced after the operation. The rate of reduction declined between the third and fifth postoperative years. On the other hand, the mean distance between the occiput and the atlas as well as the mean angle of the axis and the atlas did not change significantly. The range of motion of the axis and the seventh cervical vertebra was decreased after the operation, and it continued to decrease slowly over the study period. The range of motion of the occipito-atlanto-axial complex increased slightly, which may represent a compensation for the decreased mobility of the middle and caudad parts of the cervical spine. CONCLUSIONS: Laminaplasty diminishes lordosis and straightens the cervical spine. The range of motion and lordosis continued to decrease, though at a diminishing rate, between the third and fifth postoperative years.

Posterior movement and enlargement of the spinal cord after cervical laminoplasty.

We performed CT myelography in 38 patients with cervical myelopathy before and after laminoplasty to enlarge the canal. The sagittal and transverse diameters, the cross-sectional area, and the central point of the spinal cord were measured. After cervical laminoplasty, the mean sagittal diameter of the spinal cord at C5 increased by 0.8 mm, but the mean transverse diameter decreased by 0.9 mm. The mean cross-sectional area of the cord increased by 7.4% and that of the dural sac and its contents by 33.8% at C5. The centre of the spinal cord moved a mean 2.8 mm posteriorly at this level. Enlargement of the spinal canal is sufficient to decompress the spinal cord, but posterior movement may be the limiting factor in determining the decompressive effect of laminoplasty.

[Effect of a direct electric current on modification of bone and ligament repair processes--experimental investigation of a rabbit model].

Investigations of the effect of direct current on 1) fracture healing, and 2) ligament healing was conducted by applying 10 microA to 1) the defect of the fibula, and 2) that of the patellar ligament of adult rabbits. After time periods for stimulation all specimens were tested with combinations of roentgenological, histological, biomechanical and biochemical methods. The results were analyzed and compared with the non-stimulated, opposite side and with the normal tissue. The electricity produced 1) a more massive callus with normal histological features in an early stages at the fracture site, and 2) higher tensile stiffness and earlier change of the collagen types in the newly-formed tissue, though no significant differences were observed as to 1) the mechanical parameters of callus and bone material, and 2) histological findings of repairing tissue. Electrical stimulation was indicated not only on bone tissue but also on non-osseous tissues and their components.