Hitoshi Kise’s scientific contributions

Between 1996 and 1999, eleven males underwent salvaged operation after Percutaneous Laser Disc Decompression (PLDD) at other hospitals. Their age ranged from 28 to 92 years old (mean: 56.6 years) and follow-up period from 1 month to 37 months (mean: 19 months). PLDD was performed on the cervical spine in 4 cases and lumbar spine in 7 cases. The numbar of PLDDs ranged from 1 to 8 times (mean: 3.3). At the time of salvaged operation, our diagnosis was lumbar herniated intervertebral disc (LHID) in 4 cases, cervical pyogenic discitis (CPD) in 2, and indivisual cases of cervical spondylotic myelopathy (CSM), cervical ossification of the posterior longitudinal ligament (OPLL), lumbar canal stenosis (LCS), lumbar discopathy, and lumbar extradural abscess (LEA).Salvaged operations were posterior discectomy in 4 cases of LHID, anterior decompression and fusion in 2 cases of CPD and OPLL, laminoplasty for CSM, PILF for LCS, PL-F for lumbar discopathy and laminectomy and debridement for LEA in one each.The snspected causes for requiring salvaged operations were no improvement after PLDD with appropriate indication in 4 patients, no improvement with inappropriate indication in 3, infection in 3, and in one case the cause was unknown.

Neurinoma is the most common spinal cord tumor. However neurinoma with large cystic changes are rare. We experienced two cases of this condition in the lumbar spine: A 53-year-old male suffering from low back pain and bilateral buttock and thigh numbness; and a 40-year-old female complaining of low back and left lower limb pain and pollakisuria. The MR images of both cases showed an intradural tumor with large cystic change, which represented low signal in T1-weighted images and high signal in T2-weighted images. In the contrast MR images of case 2 the cyst wall was clearly enhanced with Gd-DTPA. Both tumors were removed surgically and pathologically diagnosed as Antoni-B type neurinoma.No evidence of any postoperative neurological defect was shown.Contrast-enhaced MR images should be taken to differentiate between a cystic neurinoma and an arachnoidal cyst.

We studied 23 cases (17 males, 6 females) with suppurative spondylitis to find out the characteristics which affect the clinical course. Two cervical cases and 11 thoracoo-lumbar cases recuperated with intravenous antibiotics, however, four cervical cases and six thoraco-lumbar cases needed surgery after antibiotic administration. Thoraco-lumbar cases aged under 14 years could be treated conservatively. The surgical cases revealed the following characteristics: palsy due to kyphotic deformity of the cervical spine, and long-standing (>8 weeks)/recurrent inflammation in the thoraco-lumbar spine despite antibiotic admimistration. Regarding the area of osteolysis shown on radiographs and high intensity areas in MR images, significant differences were not seen between conservatively and surgically treated cases at any spinal level. High intensity area in T2 weighted images extended to the whole body of the cervical spine.

We reviewed the surgical results of 18 patients suffering from thoracic myelopathy caused by ossification of the yellow ligament (OYL) and investigated the factors affecting postoperative results. The percentage of clinical recovery, which was calculated from the JOA score before and after surgery, averaged 54.9%. Factors investigated were age at surgery, delay of surgery after onset of symptoms, JOA score before surgery and percentage of narrowing of spinal canal calculated from CT myelography. Correlation between percentage of clinical recovery and these factors were analyzed. There was a significant negative correlation between the percentage of clinical recovery and delay of surgery. No significant correlation was found between the other factors. Therefore, we recommend early diagnosis and early surgery without delay.

We experienced two cases of extradural arachnoid cysts in the thoracolumbar region.Case 1: A 13-year-old female suffered from low back pain and progressive weakness of her lower limbs. MRI and myelogram showed a cystic lesion located in the posterior part of the spinal canal which was compressing the spinal cord at the Th12-L3 level. Cine MRI revealed turbulence in the cyst and spinal fluid flow between the subarachnoid space and cyst. We confirmed that the extradural arachnoid cyst communicated with the subarachnoid space. After extirpation of the cyst and closure of the communicating fissure, complete motor recovery was seen and the patient's low back pain disappeared.Case 2: A 65-year-old female suffered from low back pain and was unable to walk due to palsy of her lower limbs. Although an arachnoid cyst at the Th11-L2 level was suspected from MRI and myelogram, neither turbulence in the cyst nor communication flow was seen in tine MRI. Fluid aspiration improved the palsy of her lower limbs, however MRI taken 3 days later revealed accumulation of fluid and the palsy exacerbated after 3 weeks. Surgery was performed, at which time it was found that the arachnoid cyst communicated with the subarachnoid space. The cyst was extirpated and the connecting pedicle ligated. Complete motor recovery was seen 3 months after surgery.

Aneurysmal bone cysts (ABC) arising from the cervical spine in children is relatively rare. Two cases with aneurysmal bone cysts arising from the cervical spine were successfully operated on in order to achieve radical tumor resection and reconstruction cervical spine stability were reported.Case1: A five year-old boy with neck pain and limitation of cervical movements. Clinical and histological investigation revealed ABC at the body of C4. Extensive curettage and bone grafting from C3 to C5 spine were carried out. Complete bony union was achieved. At six years follw-up, no tumor recurrence was seen, the spinal canal had normal growth and the patient had returned to normal activity.Case 2: A twelve year-old girl. Radiological examination and histological findings revealed ABC extensively occupying the body and lamina of C4. Staged resection and reconstruction were done. In the first stage, wide curettage through the posterior approach followed by bone grafting with Luque instrumentation were done. Two weeks later extensive curettage of the C4 lesion, cervical interbody fusion with bone grafting and plating from C3 to C5 were carried out. At three years follow-up, complete bony union was observed with no recurrence of the lesion, nor any disturbance of spinal canal growth.

we experienced two cases of thoracic disc herniation associated with ossification of the yellow ligament (OYL).Case 1 A 68-year-old male, who presented with muscle weakness of the lower limbs and gait disability was diagnosed as having Th9/10 disc herniation associated with Th9-11 OYL. Th9-11 laminectomy and transdural removal of Th9/10 disc was performed. In spite of temporary progression of muscle weakness just after surgery, he resumed full gait function.Case 2 A 45-year-old male with gait disturbance due to Th9-12 OYL was treated with Th9-12 laminectomy. Gait function improved after surgery, but recurred one year later. MRI revealed newly-formed Th9/10 disc herniation, and anterior decompression and fusion were performed at Th9/10.After the second operation almost full recovery of gait function was gained.