Published papers

Study Design. This was a retrospective study of the results of anterior decompression and fusion in patients with thoracic myelopathy secondary to ossification of the posterior longitudinal ligament with a minimum follow-up time of 5 years. Objectives. To clarify the effectiveness and limits of anterior decompression and fusion for thoracic ossification of the posterior longitudinal ligament. Summary of Background Data. Posterior decompression for the surgical management of thoracic ossification of the posterior longitudinal ligament has had an uncertain success record. Anterior decompression and fusion have been considered the treatment of choice; however, there are few reports describing the long-term results. Methods. The participants in this investigation were 33 patients whose cases were followed for an average period of 8 years and 2 months. The factors that were investigated included changes in the Japanese Orthopedic Association score and in recovery rates, postoperative complications, and radiographic findings of bone union and progression of ossification of the posterior longitudinal ligament within the area of anterior decompression. Results. Although the recovery rates were relatively stable from 1-5 years after surgery, the rates declined thereafter. The average recovery rate at the final follow-up visit was 53.2%. Postoperative complications included three cases of deterioration of thoracic myelopathy and four cases of extrapleural cerebrospinal fluid leakage. Except for the one case of deterioration of thoracic myelopathy, the remainder of the complications were transient. Conclusions. Anterior decompression and fusion is an effective surgical procedure for thoracic ossification of the posterior longitudinal ligament with good, stable, long- term results; when thoracic ossification of the posterior longitudinal ligament was extensive or coincident with ossification of the intraspinal ligament, however, the results were not as predictable.

A retrospective study of 13 patients with metastases to the upper cervical spine was designed to examine the clinical efficacy of surgical treatment. All patients had severe neck pain and two had quadriplegia. Eleven patients underwent operative posterior stabilization, and two patients were treated with a brace and radiotherapy. Pain relief after surgery was significant so that 10 of the 11 patients could leave bed and resume their normal activities. The other two patients who were treated nonoperatively had severe dementia and sudden death from a respiratory arrest after a fall, despite temporary relief from pain. Surgery may be very successful in improving the quality of life of patients who have pain and/or paralysis caused by metastases to the upper cervical spine.

The effectiveness and problems associated with the operation of anterior decompression and fusion using the manubrium splitting approach for thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL) of the upper thoracic spine carried out in nine patients was investigated. They were followed up for 1 year or more following the operation. The severity of the thoracic myelopathy was evaluated using the Japanese Orthopaedic Association score, and the surgical outcome was evaluated using recovery rates. This study includes investigation of the surgical outcome and of any postoperative complications, and radiographic observation of bony union and the progression of OPLL within the area of the anterior decompression. The caudal limit of the anterior decompression achieved by splitting the manubrium was the T3 vertebral body. A recovery rate of 71% was achieved during an average follow-up period of 35 months. Only one transient recurrent nerve palsy, and in another patient cerebrospinal fluid leakage occurred as postoperative complications. Radiographic examinations confirmed bony union in all of the patients, and there was no instance of spinal canal stenosis caused by progression of the OPLL within the area of the anterior decompression. Anterior decompression and fusion by splitting the manubrium was an effective surgical procedure for OPLL of the upper thoracic spine, to achieve a good outcome, however, the extent of anterior decompression was limited.

Incomplete cervical spinal cord injuries were produced in rats by placing 10 g or 20 g weight on exposed dura at the C6 level for 5 min (Mild or Moderate injury). These two degrees of the injury resulted in initial motor functional deficits, followed by recoveries. In this study, changes in choline acetyltransferase activity and distribution following the incomplete cervical cord injuries were investigated using radioenzyme assay, and fluorescence microphotometry. We demonstrated that mild injury led to a transient decrease of choline acetyltransferase activity in the compressed spinal cord segment, but showed almost no histologic change at two days after injury. Although a low level of choline acetyltransferase immunofluorescence was found in the ventrolateral anterior horn at two days after injury, it recovered completely by one week after injury. These findings suggest that there was a strong correlation between the transient motor functional deficit and the decrease in choline acetyltransferase activity following mild injury. Moderate injury resulted in a persistent low level of choline acetyltransferase activity in the compressed spinal cord segment accompanied by a striking loss of gray matter. On the other hand, at seven, 14 and 28 days after injury, over-expression of choline acetyltransferase activity was found in the neighboring spinal cord segments located both rostral and caudal to the injury, which showed no histologic change. In addition, excessively high levels of choline acetyltransferase immunofluorescence were found in the ventrolateral anterior horn of these segments. A strong correlation was found between the motor functional recovery and the late, e high levels of choline acetyltransferase activity in the neighboring regions. These results suggest that cholinergic neurons, especially spinal motor neurons may play an important role in the motor functional recovery following incomplete cervical spinal cord injury.