Jun Arimizu

Surgical results and related factors for ossification of posterior longitudinal ligament of the thoracic spine: A multi-institutional retrospective study

Study Design. Retrospective multi-institutional study Objective. To describe the surgical outcomes in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to clarify factors related to the surgical outcomes. Summary of Background Data. Detailed analyses of surgical outcomes of T-OPLL have been difficult because of the rarity of this disease. Methods. The subjects were 154 patients with T-OPLL who were surgically treated at 34 institutions between 1998 and 2002. The surgical procedures were laminectomy in 36, laminoplasty in 51, anterior decompression via anterior approach in 25 and via posterior approach in 29, combined anterior and posterior fusion in 8, and sternum splitting approach in 5 patients. Instrumentation was conducted in 52 patients. Assessments were made on (1) The Japanese Orthopedic Association (JOA) scores (full score, 11 points), its recovery rates, (2) factors related to surgical results, and (3) complications and their consequences. Results. (1) The mean JOA score before surgery was 4.6 ± 2.0 and, 7.1 ± 2.5 after surgery. The mean recovery rate was 36.8% ± 47.4%. (2) The recovery rate was 50% or higher in 72 patients (46.8%). Factors significantly related to this were location of the maximum ossification (T1–T4) (odds ratio, 2.43–4.17) and the use of instrumentation (odds ratio, 3.37). (3) The frequent complications were deterioration of myelopathy immediately after surgery in 18 (11.7%) and dural injury in 34 (22.1%) patients. Conclusion. The factors significantly associated with favorable surgical results were maximum ossification located at the upper thoracic spine and use of instrumentation. T-OPLL at the nonkyphotic upper thoracic spine can be treated by laminoplasty that is relatively a safe surgical procedure for neural elements. The use of instrumentation allows correction of kyphosis or prevention of progression of kyphosis, thereby, enhancing and maintaining decompression effect, and its use should be considered with posterior decompression.

Measurement of the Local Pressure of the Intervertebral Foramen and the Electrophysiologic Values of the Spinal Nerve Roots in the Vertebral Foramen

Study Design. The intraoperative findings of the local pressure of the intervertebral foramen and the electrophysiologic values of the spinal nerve roots were evaluated. Objective. To investigate the neurophysiologic changes of the spinal nerve roots in the vertebral foramen. Summary of Background Data. As far as we know, few reports have so far described the neurophysiologic changes of the spinal nerve roots in the vertebral foramen. Methods. The local pressure of the intervertebral foramen was continuously measured while the lumbar spine posture was changed in 66 vertebral foramens. In addition, 20 L5 nerve roots were electrophysiologically evaluated using the compound muscle action potentials (CMAPs) from tibialis anterior (TA) muscle after L5 nerve root stimulation. Results. The local pressure of the intervertebral foramen was significantly increased during lumbar spine extension (P < 0.001); moreover, the latency and amplitude of the CMAPs both significantly deteriorated in line with the increasing local pressure. Conclusions. Our findings suggested that a double compression of the nerve root exists in lumbar spinal stenosis with lumbar spine extension, which includes the spinal canal and the vertebral foramen.

Neurogenic intermittent claudication in lumbar spinal canal stenosis: the clinical relationship between the local pressure of the intervertebral foramen and the clinical findings in lumbar spinal canal stenosis.

Study Design The clinical relationship between the local pressure of the intervertebral foramen and the clinical findings in lumbar spinal canal stenosis were evaluated. Objective To investigate the pathogenesis of neurogenic intermittent claudication in lumbar spinal canal stenosis. Summary of Background Data The genesis of neurogenic intermittent claudication is generally considered to result from nerve root ischemia; however, the exact pathogenesis of neurogenic intermittent claudication remains uncertain. Methods From a total of 20 lumbar spinal canal stenosis patients, 29 L5/S1 vertebral foramens were studied. All patients showed neurogenic intermittent claudication, and also showed neurologic abnormalities in L5 area. Intraoperatively, the local pressure of the intervertebral foramen was continuously measured using a micro-tip catheter transducer whereas the lumbar spine postures were changed under passive movement, and the relationships between the local pressure and the preoperative clinical findings in lumbar spinal canal stenosis were analyzed. Results The local pressure of the intervertebral foramen significantly increased during lumbar spine extension (P<0.001). The patients who demonstrated large changes in the local pressure between flexion and extension showed a significantly poor walking ability (P=0.003). Moreover, the patients who had 2-level lumbar spinal canal stenosis showed significantly smaller changes in the local pressure between flexion and extension than 1-level lumbar spinal canal stenosis patients (P=0.01). Conclusions The present study suggests that the genesis of neurogenic intermittent claudication in lumbar spinal canal stenosis may be greatly affected by the variation of the dynamic mechanical stress on the spinal nerve roots of the lumbar spine, rather than the static mechanical stress on the spinal nerve roots with each posture. Moreover, 2-level lumbar spinal canal stenosis patients demonstrated radicular symptoms with relatively less external stress on their spinal nerve roots in the vertebral foramen than that observed in 1-level lumbar spinal canal stenosis patients.

Combined measurement of nerve root blood flow and electrophysiological values: intraoperative straight-leg-raising test for lumbar disc herniation.

Study Design. A total of 15 patients with lumbar disc herniation at the L5–S1 disc level who underwent microendoscopic discectomy were examined. The nerve root blood flow and electrophysiological values were measured during an intraoperative straight-leg-raising (SLR) test. Objective. To investigate the relationships between nerve root blood flow changes and the electrophysiological values during an intraoperative SLR test. Summary of the Background Data. It is unknown how the electrophysiological values are affected by nerve root blood flow changes during an SLR test. Methods. We measured S1 nerve root blood flow and electrophysiologically evaluated the nerve root using the compound muscle action potentials (CMAPs) from the gastrocnemius muscle after S1 nerve root stimulation during an intraoperative SLR test. Subsequently, we analyzed the relationships between the nerve root blood flow changes and the electrophysiological values. Results. Before discectomy, there were sharp decreases in the nerve root blood flow after 1 and 3 minutes of the SLR test (P < 0.001), and the amplitudes of the CMAPs deteriorated significantly (P < 0.001). Significant correlations were found between the decrease ratio for the nerve root blood flow during the SLR test and the deterioration ratio for the amplitude of the CMAPs. After discectomy, the blood flow increased significantly (P = 0.001). When the SLR test was performed again, the blood flow showed no significant decreases. The average amplitudes of the CMAPs were significantly ameliorated (P < 0.01). When the SLR test was performed again, no significant differences were found for the average amplitudes after 1 and 3 minutes of the test. Conclusion. Significant correlations were found between the decrease ratio for the nerve root blood flow and the deterioration ratio for the amplitude of the CMAPs. The present results demonstrate that temporary ischemic changes in the nerve root cause transient conduction disturbances.

Lumbosacral Fixation by Use of Intrasacral Fixation Method

We operated on cases of degenerative lumbosacral kyphosis by use of the Isola-galveston method. However, correction of pelvic posterior rotation was unsatisfactory and instrumentation failure occurred. Two years ago, we introduced posterior wedge vertebral osteotomy in which shortening and fixture by the intrasacral fixation (ISF) method are performed. We operated on 6 cases by this method. At follow-up (mean: 11 months), the cases showed remarkabe improvement of the clinical symptoms and good correction of the lumbosacral alignment. This method was found to reasonably correct flat backs and maintain correction during follow-up.

Thymol Turbidity test (TTT) and Zinc Sulfate Turbidity test (ZTT) for Rheumatoid Arthritis

We studied the Thymol Turbidity test (TTT) and Zinc Sulfate Turbidity test (ZTT) in the serum of 83 patients with rheumatoid arthritis (RA). TTT or ZTT was high in 63 of 83 patients (75.9%) with RA. All patients were divided into two groups, according to high or low values for serum CRP, erythrocyte sedimentation reaction and Lansbury index. TTT and ZTT from the high group were higher compared to the low group. 21 or 27 patients. whose TTT or ZTT was not high, had a positive rheumatoid factor test. However TTT or ZTT were high in 7 patients, whose rheumatoid factors were negative. Most of these cases had high RA activity. It was suggested that TTT and ZTT are useful indices for RA activity although less significant compared to rheumatoid factor.