Hirokazu Nohara’s research while affiliated with Honjo Daiichi Hospital and other places

We report a case who was treated by cervical laminoplasty, thoracic posterior decompression, and fusion with instrumentation. A 67-year-old woman had limped for four years, but she could walk independently. After rear end crash of her car 2 years ago, she could not walk steadily because of spasiticity. She could not go up and down the stairs without using a handrail from four months ago and visited a doctor. Magnetic resonance imaging (MRI) showed compression-like ossification of posterior longitudinal ligament (OPLL) at the cervical and thoracic spine and she was refered to our hospital. At first examination, she complained of numbness of her legs and dullness below her chest. Both her legs were spastic and weak. MRI showed compression of the spinal cord by hypertrophy of the posterior longitudinal ligament from C5 to Th8 and hypertrophy of the yellow ligament at Th4/5, Th5/6. CT showed no apparent ossification of the ligament. We performed laminoplasty from C4 to C7 and posterior decompression and fusion from Th1 to Th8. Two months after operation, she could walk independently. The pathological diagnosis of the yellow ligament was fibrous tissue and partial cartilaginous tissue.

Vertebral assimilation was observed in an adult male Ainu skeleton from the Tokoro Chashi site of the early modem period in Tokoro, Hokkaido, Japan. The vertebral bodies and right zygapophyseal joint between the 12th thoracic and 1st lumbar vertebrae were completely united by osseous tissue, with anterior wedge shape and 42% loss of anterior vertebral body height. Differential diagnosis suggested that this was a healed state of pyogenic spondylitis.

Thirty fresh-frozen calf cadaveric spinal specimens (L3-L6) were used to investigate the effect of flexible stabilization and fixation on the adjacent intervertebral motion segment. The intact spine that had not been subjected to injury was used for comparison as control. The destabilized spine was made up of specimens from which the bilateral facet joints and the supraspinous and interspinous ligaments were removed. The flexible stabilized spine was applied with pedicle screws and polyethylene-terephthalate bands, and the fixed spine was applied with pedicle screws and rods at the L4-L5 segment. The range of motion (ROM) was measured under flexion, extension, and bilateral bending moments, and the ROM ratio (ROM of each model versus ROM of the comparison model) was calculated at L3-L4, L4-L5, and L5-L6 segments. In the flexible stabilized spine, the restriction of motion was high under flexion and bilateral bending moments, and the mobility of the adjacent intervertebral motion segments approximated the normal lumbar vertebra. In the fixed spine, the ROM ratio increased at the cranial and caudal adjacent segments.