A history of spinal surgery in neurosurgery of Japan is reviewed in dividing into three stages. First stage (the preceding days of the year 1948 when The Japan Neurosurgical Society was founded) : Dr. H. Miyake was the first surgeon who removed successfully a cervical spinal cord tumor in 1911. During this period either general or orthopedic surgeons undertook spinal surgery. No neurosurgical institution was established at this stage. Second stage (from 1948 to the year 1986 when the Japanese Society of Spinal Surgery was founded) : Until 1957 orthopedic surgeons had been main contributors presenting papers of spinal surgery in the annual meeting of the Japan Neurosurgical Society. A paper of cervical disc disease by Dr. M. Tsuru in the 17th meeting (1958) was the first spinal paper presented by a neurosurgeon in the annual meeting. Following him neurosurgeons handling spinal surgery gradually increased and became playing major roles instead of orthopedic surgeons since 1973. Symposiums and panels encouraged increase of neurosurgeons engaged in spinal surgery. Number of spinal papers presented in the annual meeting reached 4 to 6% in 1985. These up-going tendency forced to organize the Japanese Society of Spinal Surgery in 1986. Third stage (from 1986 up to the present) : Establishment of training programs for spinal neurosurgeons was a main issue at this stage. Several hands-on-workshops on spinal surgery using cadavers has being arranged as well as regional meetings to discuss clinical cases in detail. Leading institutions open their residency programs particularly designed for spinal neurosurgeons. A survey revealed spinal operations totaled 5, 161 in a year from 1995 to 1996, which were 5.6% of the total 86, 830 neurosurgical operations (the response rate to questionnaires was 59.7%). At the 57th annual meeting (1998), 9.4% of total 1104 papers were related to spinal surgery.

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The purpose of this study was to analyze revision surgery for traumatic cervical injuries after unsuccessful stabilization and to discuss the indication for posterior instrumentation. Four hundred and one patients who sustained cervical injuries underwent either combined anterior-posterior or simple posterior reduction stabilized with posterior instrumentations. All patients were divided into three groups with respect to posterior instrumentation. There were 383 patients treated with interspinous process wiring and sandwich bone grafting, 6 patients had Luque sublaminar wiring and 12 had lateral mass plating. The cases which required revision surgery after failure of the first reconstructive surgery were investigated to assess the indication for posterior instrumentation based on the fact that the initial stabilization was unsucfessful. Of 383 patients treated with interspinous process wiring, only 6 patients (1.6%) required revision surgery. It was observed that lack of success in three of 4 of these patients was attributable to technical failure and in another to a lack of recognition of traumatic spondylolysis. No case with Luque sublaminar wiring needed revision surgery. Of 12 patients with lateral mass plating, two cases (16.7%) required revision. One was caused by a lack of recognition of traumatic spondylolysis and another by a weakness of the screw fixation. Considered from the fact that there was a very low revision rate after initial reconstructive surgery using posterior instrumentation, and also from the fact that there was a extreme low revision rate using less invasive interspinous process wiring, which was applied in 95% of cervical injuries, it is indicated that posterior instrumetation stabilization following our indication is appropriate for initial treatment of traumatic cervical instability. Facet articulation and spinous processes play an important role in stabilizing traumatized cervical spines using interspinous process wiring, but when they are destroyed, other posterior instrumentations have to be applied. Most traumatic cervical injuries were able to be treated successfully with less invasive interspinous process wiring and sandwich bone grafting. The procedure of posterior instrumetation stabilization should be considered as the first choice for treatment of traumatized cervical spines.

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Technical difficulty in anterior cervical fusion for elder patients is attributable to narrowing of intervertebral spaces and fusion problems due to osteoporosis of both donor grafts and recipient sites. These problems could be resolved by the use of the method of anterior cervical fusion using autologous vertebral grafts. A retrospective comparative analysis was done in 14 patients elder than 70 (the elder age group) and 46 patients younger than 70 (the younger age group) who underwent anterior cervical fusion using vertebral grafts obtained from the fusion site in our institutes. An average follow-up period was 33 months (range 6 to 55 months). Sufficient decompression of the anterior cervical pathology was performed successfully via a wider operative field. The symptoms and neurological score improved significantly without any new deficits in all patients except for a 50-year-old man with a three-level fusion who needed reoperation for further decompression. Although the preoperative Neurosurgical Cervical Spine Scale (NCSS) was significantly worse in the elder age group, the improvement rate was as good as that in the younger age group (77±5.8% vs. 88±2.8%). No major graft complications such as graft extrusion or pseudoarthrosis occurred. No graft fracture was noted in the elder age group, while it was noted in five patients in the younger age group. Cervical alignment was preserved in all the cases in the elder age group, while five patients in the younger age group showed kyphotic changes. Although the method was technically demanding, it was useful in elder patients because of major advantages such as a wider operative field, excellent graft fusion in osteoporotic patients, and no need for an additional incision to obtain autogenous bone graft, which factor allowed early mobilization.

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Posterior ooccipito-cervical fixation was accomplished in 6 patients (5 females and 1 male) by using titanium loops and sublaminar cables. Two were cases of irreducible traumatic atlanto-axial dislocation, 1 was a case of axis destroying neurofibroma, 2 were cases of craniocervical instability following the transcondylar approach to tumors, and 1 was a case of atlanto-axial dislocation associated with long lasting hemodialysis. After the occipital bone and C1-C4 lamina were exposed, sublaminar wiring was carried out with double strands of titanium cables. The titanium loop and the iliac bone graft were fixed separately with the cables. In all cases, immediate postoperative stabilization was established. Good bony fusion was obtained in 5 cases who underwent iliac bone graft. In one metastatic tumor case, postoperative stabilization was obtained without bone grafting and lasted through her life. Limitation of neck movement involved mainly rotation and extension. There are various types of devices for occipito-cervical fixation but basically they are divided into two groups : loop-with-cable method and plate-with-screw method. The loop and cables method is technically simple and provides secure stabilization, but we should be careful about possible spinal cord injury due to sublaminar wiring and long fusion segments. The plate and screws method provides strong fixation with relatively shorter fusion segments, but it's major drawback is possible injury of the vertebral artery and neural structures. In conclusion, we maintain that adequate stabilization can be obtained by titanium loop and cable in the majority of patients with craniocervical instability.

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Some 3-5% of Japanese over the age of 40 are estimated to have ossification of the posterior longitudinal ligament (OPLL). Few, however, require surgery, and surgical indications and procedures remain controversial. We evaluated two surgical procedures and present cervical OPLL treatment indicators. Our cervical OPLL series consisted of 163 surgically treated patients, 102 men and 61 women (average age : 57.1 years), 80 undergoing anterior decompression and 83 patients posterior decompression. Results showed 142 (88%) improved, 12 (7%) slightly improved, (4%) remained unchanged and 2 became worse. Postoperative complications occurred only in anterior-decompression cases, and involved grafted bone dislocation in 5 cases, subcutaneous CSF leakage in 5, C5 radiculopathy in 3, and anterior iliac crest fracture in 1. Anterior and posterior approaches cannot be easily compared, but our results suggest postoperative prognosis was satisfactory in both groups but posterior decompression was safer. Surgery should therefore be considered if further motor weakness develops or has existed as a sign of myelopathy.

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The number of elderly patients presenting thoracic pain due to kyphotic deformity or back pain has increased. Surgical treatment is indicated for those who have a lesion responsible to the clinical symptom. There were 17 individuals who underwent surgery for their kyphotic deformity and/or thoracic pain syndrome. There were 15 women and 2 men, age distribution form 65 to 78 years of age, with 69 years on the average. There were 6 patients with kyphotic deformity, 3 patients with thoracolumbar wedge-shaped fracture, 4 patients with thoracic disk hernia, 3 patients with thoracic spinal stenosis, and 1 patient with a combination of thoracic disk hernia and ossification of yellow ligament. As for clinical symptoms, intractable pain in the chest and/or back was recognized in all patients, while myelopathy existed in 6 patients. The anterior approach was employed in 14 patients, while, in 3, the posterior approach was preferred. Preoperative spinal angiography was performed in 7 cases in which instrumentation surgery had been planned. The segmental artery distributing the artery of Adamkiewicz was mobilized and preserved for the maintenance of the spinal cord blood supply. Postoperative pain relief was achieved in all patients with the degree of excellent in 12 patients, good in 3 patients, and fair in 2 patients. The improvement of myelopathy after surgery was recognized in 5 patients out of 6 preoperative myelopathic cases. In conclusion, we found that surgical treatment for thoracic pain syndrome and for kyphotic deformity seems to be quite efficacious even if the patients are aged.

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The authors report and describe the clinical features of a case of myelopathy caused by developmental anomaly of the posterior arch of the atlas. This clinical entity is very rare and only 6 cases have been reported up to the present. The 6 reported cases and our case have several clinical features in common. First, all patients were men. Second, patients developed such symptoms as spastic gait and hypersthesia after middle age. Third, the sagittal canal diameter was less than 10mm at the level of the atlas and less than 13mm at lower levels. Fourth, laminectomy or laminoplasty may be effective in alleviating symptoms. These features indicate that this disorder is a developmental anomaly associated with constitutional developmental cervical canal stenosis.

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Chiari malformation is a congenital deformity usually found in infancy or childhood. Its occurrence in adult years has recently received attention. The present report describes a woman with Chiari malformation type I who became symptomatic with headache and unsteadiness at the age of 65, and was operated on at 75. Postoperatively she improved remarkably and was discharged without any neurological deficits. There was no evidence of syrinx or spina bifida associated with the malformation in this patient. Such a phenomenon is rare.

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