Nobumasa Suzuki

MRI of cervical intervertebral discs in asymptomatic subjects

We studied degenerative changes in the cervical intervertebral discs of 497 asymptomatic subjects by MRI and evaluated disc degeneration by loss of signal intensity, posterior and anterior disc protrusion, narrowing of the disc space and foraminal stenosis. In each subject, five disc levels from C2-C3 to C6-C7 were evaluated. The frequency of all degenerative findings increased linearly with age. Disc degeneration was the most common observation, being present in 17% of discs of men and 12% of those of women in their twenties, and 86% and 89% of discs of both men and women over 60 years of age. We found significant differences in frequency between genders for posterior disc protrusion and foraminal stenosis. The former, with demonstrable compression of the spinal cord, was observed in 7.6% of subjects, mostly over 50 years of age. Our results should be taken into account when interpreting the MRI findings in patients with symptomatic disorders of the cervical spine.

Increased signal intensity of the spinal cord on magnetic resonance images in cervical compressive myelopathy. Does it predict the outcome of conservative treatment

STUDY DESIGN Correlation between a lesion of the spinal cord that elicits increased signal intensity (ISI) on magnetic resonance images (MRIs) and the outcome of conservative treatment for cervical compressive myelopathy was retrospectively investigated. OBJECTIVE To investigate whether ISI could predict the outcome of conservative treatment for cervical compressive myelopathy. SUMMARY OF BACKGROUND DATA It is unknown whether ISI is related to the outcome of conservative treatment for cervical compressive myelopathy. METHODS Fifty-two patients with mild cervical myelopathy underwent conservative treatment with a cervical brace. The compressive lesions were spondylosis in 29 patients, disc herniation in 12, and an ossification of the longitudinal ligament in 11. They also underwent MRI (1.5 T), and ISI was evaluated on T2-weighted sagittal and axial images. The ISI areas were classified as focal or multisegmental. Thirty-nine patients underwent follow-up MRI after a mean interval of 2 years, 4 months. The transverse area of the spinal cord was also measured on T2-weighted axial images. The outcome of conservative treatment was assessed using the Japanese Orthopedic Association Score (JOA score). Patients showing either an improvement in the JOA score or with a JOA score of 15 or more were considered to have a satisfactory outcome. RESULTS The average JOA score was 14.0 +/- 1.4 (range, 10-16) before conservative treatment and 14.4 +/- 1.9 (range, 10-17) at follow-up. The average gain in the JOA score was 0.4 points +/- 1.9 (range, -5 to +6). The outcome was satisfactory in 36 patients (69%). An area of ISI was observed in 34 patients (65%) before treatment (24 focal and 10 multisegmental). A satisfactory outcome was obtained in 78% of the patients without ISI, in 63% of those with focal ISI, and in 70% of those with multisegmental ISI. No statistically significant difference was seen among these three groups in the percentages of patients with satisfactory outcome, JOA scores before and after treatment or transverse spinal cord area. Of the 39 patients who were re-examined by MRI, 28 showed an area of ISI. The ISI regressed in five patients (18%). Satisfactory outcome was obtained in all 5 patients with regression of ISI, in 16 (70%) of the 23 patients without regression of ISI, and in 10 (91%) of the 11 patients without ISI apparent on the the first images (difference, not significant). CONCLUSIONS Increased signal intensity was not related to a poor outcome of conservative treatment or severity of myelopathy in the patients with mild cervical myelopathy.

Long-term Follow-up Study of Anterior Decompression and Fusion for Thoracic Myelopathy Resulting From Ossification of the Posterior Longitudinal Ligament

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.

Realignment of postoperative cervical kyphosis in children by vertebral remodeling

Study Design This study analyzed radiographically change in the sagittal curvature of the cervical spine after atlantoaxial (C1–C2) posterior fusion in children. Objectives This study clarified the process of spinal remodeling after postoperative cervical deformation in children. Summary of Background Data Postoperative spinal deformations in children are observed frequently. However, there have been only a few reports on postoperative changes in the sagittal curvature of the cervical spine and spinal remodeling after those changes. Methods Between 1979 and 1991, there was a total of 12 children who underwent C1–C2 posterior fusions. The average age at the time of surgary was 9.8 years. The alignment of the cervical spine was classified into four groups (lordosis, straight, kyphosis, and swan-neck deformity). radiographic findings suggestive of the remodeling were as follows: 1) new bone formation on the anterior vertabral cortex, and 2) increase in body/canal ratio (BCR). The follow-up period averaged 6.2 years. Results Postoperative cervical malalignment (kyphosis or swan-neck deformity) occurred in four patients. In all four patients, new bone forma tion and increase in BCR at the apex of kyphosis were observed. Therefore, there was gradual improvement of the malalignment by vertebral remodeling. This phenomenon was not observed in eight patients with normal alignment. Conclusion Realignment of postoperative cervical kyphosis by vertebral remodeling was observed in children. the results of this study suggested that remodeling occurred even in the spine, which was similar to the remodeling in long bones.

Cervical curvature in acute whiplash injuries: prospective comparative study with asymptomatic subjects

The cervical curvature of 488 patients with acute whiplash injury was prospectively studied by comparison with 495 asymptomatic healthy volunteers. Plain radiography of the cervical spine in the neutral position was evaluated qualitatively. No significant difference was noted in frequencies of non-lordotic cervical curvature and local angular kyphosis between acute whiplash injury patients and asymptomatic subjects. No significant association was apparent between clinical symptoms and cervical curvature. These results suggest that non-lordotic cervical curvature and angular kyphosis in acute whiplash injury patients constitute normal variants rather than pathological findings.

Factors of thoracic cage deformity that affect pulmonary function in adolescent idiopathic thoracic scoliosis.

Study Design. This clinical study examined the association between pulmonary function and thoracic cage deformities in scoliosis. Objective. To determine the factors in spinal and thoracic cage deformities that affect pulmonary function in scoliosis. Summary of Background Data. Pulmonary function in scoliosis has generally been evaluated in terms of lateral spinal curvature. No previous report has evaluated changes in pulmonary function taking into consideration measurements reflecting not only spinal curvature but also thoracic cage deformities, although scoliosis is a three-dimensional deformity. Methods. A total of 109 patients (mean age, 14.2 years) with adolescent idiopathic right thoracic scoliosis (mean lateral spinal curvature, 37.7°) had full assessment of pulmonary function and a radiographic evaluation from radiographs of the whole spine, Moiré topography, and thoracic computed tomography. Results. Multiple regression analysis (stepwise method) was performed at each vertebral level from T3–T12 to identify the factor that most strongly affects %VC. The correlation coefficient was highest at T9 and next highest at T8, with values of 0.641 (r2 = 0.411, P < 0.0001) and 0.625 (r2 = 0.390, P < 0.0001), respectively. At T9, multiple regression analysis showed that the sagittal diameter of the thoracic cage and the total lung area were identified as factors that most strongly affect %VC. Similarly, the sagittal diameter of the thoracic cage and the rotation angle to the sagittal plane were identified at T8. Conclusions. The factors that reduced %VC were the sagittal diameter of the thoracic cage, total lung area and vertebral rotation at the T8 and T9 levels.

Metastases to the upper cervical spine

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.

A biomechanical study on the effects of rib head release on thoracic spinal motion

PurposeIdiopathic scoliosis is generally treated by surgical derotation of the spine. A secondary goal of surgery is minimization of the “rib hump” deformity. Previous studies have evaluated the effects of surgical releases such as diskectomy, costo-vertebral joint release, facetectomy, and costoplasty on spine mobilization and overall contribution to thoracic stability. The present study was designed to evaluate the biomechanical effects of the rib head joints alone on axial rotation, lateral bending, and segmental rotation, without diskectomy or disruption of anterior or posterior elements.MethodsFour female cadaver thoracic spines with intact sternums and rib cages were mounted in an Instron servo-hydraulic bi-axial MTS. In a 12-step sequence, the costo-vertebral and costo-transverse ligaments were released, first unilaterally from T10–T7, then bilaterally until complete disarticulation between the rib heads and the vertebral bodies. After each release, biomechanical testing, including axial rotation and lateral bending, was performed. Vertebral body displacement was also measured using electromagnetic trackers.ResultsWe found that rib displacement during axial rotation was significantly increased by unilateral rib head release, and torque was decreased with each successive cut. We also found increased vertebral displacement with sequential rib head release.ConclusionsOur results show that sequential costo-vertebral joint releases result in a decrease in the force required for axial rotation and lateral bending, coupled with an increase in the displacement of vertebral bodies. These findings suggest that surgical release of the costo-transverse and costo-vertebral ligaments can facilitate segmental correction in scoliosis by decreasing the torso’s natural biomechanical resistance to this correction.

The results of surgery on primary malignant tumors of the spine

The results of surgery on primary malignant tumors of the spine in 18 patients treated in our hospital between 1976 and 1993 were reviewed. Curettage was less effective in controlling primary malignant lesions than wide excision, and the condition of the resected margin was closely related to the prognosis of the disease. Some patients in the hematopoietic tumor group receiving combined adjuvant therapy survived for a long time. The role of surgery is important in tumors such as chordoma and chondrosarcoma that have low sensitivity to adjuvant therapy, and it is essential to secure tumor-free resected margins.

Minimum 20 Years Long-term Clinical Outcome After Spinal Fusion and Instrumentation for Scoliosis: Comparison of the SRS-22 Patient Questionnaire With That in Nonscoliosis Group.

Study Design. A retrospective minimum 20-year follow-up study using 4 standard self-administered questionnaires, one of which, the SRS-22 was also administered to control groups. Objective. To evaluate long-term postoperative pain and other clinical outcomes of scoliosis correction and fusion surgery with Harrington instrumentation using Moe square-ended rods for better preservation of sagittal alignment. Summary of Background Data. Only a few long-term outcome studies have used standardized and validated self-administered tools, and no studies have established SRS-22 control data within their own population. There is no previous minimum 20-year follow-up evaluation after correction surgery preserving thoracic kyphosis and lumbar lordosis. Methods. Of 86 consecutive patients who underwent instrumentation surgery for scoliosis by a single surgeon, 61 patients participated using Japanese Orthopaedic Association, Roland-Morris Disability Questionnaire, Oswestry Disability Index, and Scoliosis Research Society (SRS-22) questionnaires and 51 patients were included in this study. Results were analyzed for pain and other clinical outcomes. A total of 771 hospital employees were sent SRS-22 questionnaires. A total of 763 responded, resulting in 2 control groups composed of nonscoliosis and untreated mild scoliosis controls of the same culture and language as the long-term follow-up group. Results. The prevalence of continuous low back pain was about 15%. Average Japanese Orthopaedic Association, Oswestry Disability Index, and Roland-Morris Disability Questionnaire scores at follow-up were 25 points, 7.3%, and 1.6, respectively. The average SRS-22 scores were 4.2 (function), 4.3 (pain), 3.7 (self-image), and 3.9 (mental health) for the postoperative follow-up group compared with 4.5 (function), 4.3 (pain), 3.5 (self-image), and 3.5 (mental health) for the nonscoliosis controls. Conclusion. Improved preservation of normal sagittal alignment resulted in a prevalence of low back pain comparable with the age-matched general population. Moreover, SRS-22 results for self-image and mental health were positive compared with the controls, possibly reflecting the surgeons emphases on mental health and management of patient expectations. Level of Evidence: 4