Kazuo Yonenobu

Activating transcription factor 3 (ATF3) induction by axotomy in sensory and motoneurons: A novel neuronal marker of nerve injury.

Activating transcription factor 3 (ATF3), a member of ATF/CREB family of transcription factors, is induced in a variety of stressed tissue. ATF3 regulates transcription by binding to DNA sites as a homodimer or heterodimer with Jun proteins. The purpose of this study was to examine the expression and regulation of ATF3 after axonal injury in neurons in dorsal root ganglia (DRG) and spinal cord. In naive rats, ATF3 was not expressed in the DRG and spinal cord. Following the cut of peripheral nerve, ATF3 was immediately induced in virtually all DRG neurons and motoneurons that were axotomized, and the time course of induction was dependent on the distance between the injury site and the cell body. Double labeling using immunohistochemistry revealed that the population of DRG neurons expressing ATF3 included those expressing c-jun, and in motoneurons ATF3 and c-jun were concurrently expressed after axotomy. In contrast to c-jun, ATF3 was not induced transsynaptically in spinal dorsal horn neurons. We conclude that ATF3 is specifically induced in sensory and motoneurons in the spinal cord following nerve injury and should be regarded as an unique neuronal marker of nerve injury in the nervous system.

Neck and shoulder pain after laminoplasty. A noticeable complication.

Study Design The authors retrospectively analyzed the prevalence and features of neck and shoulder pain (axial symptoms) after anterior interbody fusion and laminoplasty in patients with cervical spondylotic myelopathy. Objectives To reveal the difference in prevalence of postoperative axial symptoms between anterior interbody fusion and laminoplasty and to clarify the pathogenesis of axial symptoms after laminoplasty. Summary of Background Data Outcome of the cervical surgery is evaluated on neurologic status alone; axial symptoms after laminoplasty rarely have been investigated. Such symptoms, however, are often severe enough to interfere with a persons daily activity. Methods Ninety‐eight patients had surgery for their disability secondary to cervical spondylotic myelopathy. Of those patients, 72 had laminoplasty, and 26 had anterior interbody fusion. The presence or absence of axial symptoms was investigated before and after surgery. The duration, severity, and laterality of symptoms were also recorded. Results The prevalence of postoperative axial symptoms was significantly higher after laminoplasty than after anterior fusion (60% vs. 19%; P < 0.05). In 18 patients (25%) from the laminoplasty group, the chief complaints after surgery were related to axial symptoms for more than 3 months, whereas in the anterior fusion group, no patient reported having such severe pain after surgery. Conclusions The prevalence and severity of axial symptoms after laminoplasty proved to be higher and more serious than has been believed. Such symptoms should be considered in the evaluation of the outcome of cervical spinal surgery.

Subtotal corpectomy versus laminoplasty for multilevel cervical spondylotic myelopathy : A long-term follow-up study over 10 years

Study Design. A retrospective study was conducted. Objective. To compare the long-term outcomes of subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy. Summary of Background Data. No study has compared the long-term outcomes between subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy. Methods. In this study, 23 patients treated with subtotal corpectomy and 24 patients treated with laminoplasty were followed up for 10 to 14 years after surgery. Neurologic recovery, late deterioration, axial pain, radiographic results (degenerative changes at adjacent levels, alignment, and range of motion of the cervical spine), and surgical complications were compared between the two groups. Results. No significant difference in neurologic recovery was found between the two groups 1 and 5 years after surgery, or at the latest follow-up assessment. Neurologic status deteriorated in one patient of the subtotal corpectomy group because of adjacent degeneration, and in one patient of the laminoplasty group because of hyperextension injury. Axial pain was observed in 15% of the corpectomy group and in 40% of the laminoplasty group (P < 0.05). In the corpectomy group, listhesis exceeding 2 mm developed at 38% of the upper adjacent levels, and osteophyte formation at 54% of the lower adjacent levels. In the laminoplasty group, kyphotic deformity developed in one patient (6%) after surgery. In the corpectomy group, the mean vertebral range of motion had decreased from 39.4° to 19.2° (49%) by the final follow-up assessment. In the laminoplasty group, the mean vertebral range of motion had decreased from 40.2° to 11.6° (29%) by the final follow-up assessment. Neurologic complications related to the surgery occurred in two patients (one myelopathy from bone graft dislodgement and one C5 root palsy from bone graft fracture) of the corpectomy group and four patients (C5 root palsy) of the laminoplasty group. All of these patients recovered over time. The corpectomy group needed longer operative time (P < 0.001) and tended to have more blood loss (P = 0.24). Six patients in the corpectomy group needed posterior interspinous wiring because of pseudarthrosis. Conclusions. Subtotal corpectomy and laminoplasty showed an identical effect from a surgical treatment for multilevel cervical spondylotic myelopathy. These neurologic recoveries usually last more than 10 years. In the subtotal corpectomy group, the disadvantages were longer surgical time, more blood loss, and pseudarthrosis. In the laminoplasty group, axial pain occurred frequently, and the range of motion was reduced severely.

Neurologic Complications of Surgery for Cervical Compression Myelopathy

Neurologic complications resulting from surgery for 384 cases of cervical myelopathy (cervical soft disc herniation, spondylosis, ossification of the posterior longitudinal ligament) were reviewed. Surgical procedures performed included 134 anterior interbody fusions (Cloward or Robinson-Smith technique), 70 subtotal corpectomies with strut bone graft, 85 laminectomies, and 95 lamino-plasties. Twenty-one patients (5.5%) sustained neurologic deterioration related to surgery. The deterioration was classified into two types on the basis of the neurologic signs observed: deterioration of spinal cord function or of nerve root function. Manifestations of the former varied from weakness of the hand to tetraparesis. Paralysis of the deltoid and biceps brachii muscles was an exclusive feature of deterioration in the nerve root group. Causes of this paralysis included malalignment of the spine related to graft complications, and a tethering effect on the nerve root following major shifting of the spinal cord after decompression. The causes of deterioration of the cord function included spinal cord injury during surgery, malalignment of the spine associated with graft complication, and epidural hematoma.

Laminoplasty versus subtotal corpectomy. A comparative study of results in multisegmental cervical spondylotic myelopathy.

A comparative study of surgical results was used to determine the tratment of choice for multisegmental cervical spondylotic myelopathy, forty-one patients who received subtotal corpectomy and strut grafting (SCS) and forty-tow undergoing laminoplasty were followed up for at least 2 years after surgery. Regarding factos known to affect surgical prognosis (age at surgery, duration of symptoms, severity of neurologic deficit, anteroposterior canal diameter, transverse area of the cord at the site of maximum compression, number of levels invoived), the two groups were statistically comparable with each other. The sevenity of neurologic deficits was assessed by the Japaneses Orthopaedic Association scale. Results were evaluated in terms of postoperative score and recovery rate, The difference between the recovery rate and final score between the two groups was not statistically significant. Surgical complications were more frequent in the subtotal corpectomy and strut grafting group than in the laminoplasty group. The most frequent complications encountered in the subtotal corpectomy and strut grafting group were related to bone grafting. Spinal aligment worsened in six patients of the laminoplasty group, but none of them suffered from neurologic deterioration, Another disadvantage of subtotal corpectomy and strut grafting was the longer postoperative period of bed rest needed to secure graft stability. We conclude that laminoplasty should be the treatment of choice for multisegmental cervical spondylotic myelopathy when neurologic results, incidence of complications, and postoperstive treatment are taken into consideration.

Interobserver and intraobserver reliability of the japanese orthopaedic association scoring system for evaluation of cervical compression myelopathy.

Study Design. The inter- and intraobserver reliabilities of an assessment scale for cervical compression myelopathy were examined statistically. This scoring system consists of seven categories: motor function of fingers, shoulder and elbow, and lower extremity; sensory function of upper extremity, trunk and lower extremity; and function of the bladder. It evaluates the severity of myelopathy by allocating points based on degree of dysfunction in each category. Objectives. To determine the inter- and intraobserver reliabilities of the revised scoring system (17 − 2 points) for cervical compression myelopathy proposed by the Japanese Orthopedic Association. Summary of Background Data. Several scales to assess clinical outcome from treatment of cervical compression myelopathy have been proposed. Most of these scales include items evaluated by observers. However, no system, including the Japanese Orthopedic Association scoring system, has yet been validated in terms of interobserver reliability. Methods. From five different university hospitals, 10 spine surgery specialists, 10 orthopedic surgeons who had just passed the board examination of the Japanese Orthopedic Association, and 13 residents in the first or second year of orthopedic residency programs were chosen. The participants in this study were 29 patients with myelopathy secondary to ossification of the posterior longitudinal ligament selected from five participating university hospitals. Several surgeons interviewed each patient twice at intervals of 1 to 6 weeks. Inter- and intraobserver reliabilities of the total score for all categories were evaluated by the intraclass correlation coefficient. The extension of the kappa coefficient of Kraemer also was calculated for each category to assess reliability of multivariate categorical data. Results. The interobserver reliability of the total score for the first interview (intraclass correlation coefficient = 0.813) and the intra- and interobserver reliabilities of the total score (intraclass correlation coefficient = 0.826) were high. The level of experience and the hospital slightly affected the reliability of the Japanese Orthopedic Association scoring system. The kappa values for intraobserver data generally were high in each category, whereasthe kappa values for interobserver data were relatively low for the categories of shoulder–elbow motor function and lower extremity sensory function. Conclusions. The inter- and intraobserver reliabilities of the Japanese Orthopedic Association scoring system for cervical myelopathy were high, suggesting that this system is useful for assessment of cervical myelopathy in comparative studies of treatment.

Choice of surgical treatment for multisegmental cervical spondylotic myelopathy.

Three surgical procedures for multisegmental cervical spondylotic myelopathy were evaluated on the basis of a follow-up study (12-157 months) of 95 patients. Twenty-four patients were treated by extensive laminectomy, 50 by anterior interbody fusion by the Cloward and/ or Smith-Robinson techniques, and 21 by subtotal spondylectomy and fusion. Results of subtotal spondylectomy were significantly (P < 0.01) better when compared with those of the other two procedures. It was concluded that spondylosis up to three disc levels should be treated by subtotal spondylectomy and fusion regardless of the canal diameter. When involvement extended four or more levels, extensive laminectomy was recommended.

Canal diameter, anteroposterior compression ratio, and spondylotic myelopathy of the cervical spine.

Nine patients with cervical spondylotic myelopathy, diagnosed during life, were subjected to detailed clinicopathologic study. The degree of cord destruction was in good correlation with the ratio of the anteroposterior diameter to the transverse diameter, designated as an anteroposterior compression ratio. Within the factors responsible for decrease in the ratio, developmental narrowing of the spinal canal was the most significant, and multiplicity of spondylotic protrusion less so. The former resulted in an extensive demyelination of the posterolateral funiculus and infarction of the gray matter. Recurrent trauma proved to cause distinct manifestations and cord pathology. Clinicopathologic correlations were also examined from the neurologic findings at the terminal stage.

The prognosis of surgery for cervical compression myelopathy. An analysis of the factors involved

We have studied the morphometry of the spinal cord in 50 patients with cervical compression myelopathy. Computed tomographic myelography (CTM) showed that the transverse area of the cord at the site of maximum compression correlated significantly with the results of surgery. In most patients with less than 30 mm2 of spinal cord area, the results were poor; the cord was unable to survive. Several factors, such as chronicity of disease, age at surgery and multiplicity of involvement are said to influence the results of surgery, but the transverse area of the cord at the level of maximum compression provides the most reliable and comprehensive parameter for their prediction.

Can intramedullary signal change on magnetic resonance imaging predict surgical outcome in cervical spondylotic myelopathy

STUDY DESIGN A retrospective study evaluating magnetic resonance imaging, computed tomographic myelography, and clinical parameters in patients with cervical spondylotic myelopathy. OBJECTIVES To investigate whether magnetic resonance imaging can predict the surgical outcome in patients with cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA No previous studies have established whether areas of high signal intensity in T2-weighted magnetic resonance images can be a predictor of surgical outcomes. METHODS Fifty patients with cervical spondylotic myelopathy were examined by magnetic resonance imaging and computed tomographic myelography before surgery and by delayed computed tomographic myelography after surgery. The correlation between the recovery rate and the clinical and imaging parameters was analyzed. RESULTS The best prognostic factor was the transverse area of the spinal cord at maximum compression (correlation coefficient, R = 0.58). The presence of high signal intensity areas on T2-weighted magnetic resonance images correlated poorly with the recovery rate (R = -0.29). However, patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poor surgical results associated with muscle atrophy in the upper extremities. Postoperative delayed computed tomographic myelography showed that multisegmental areas of high signal intensity on T2-weighted magnetic resonance images probably represent cavitation in the central spinal cord. CONCLUSIONS Patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poorer surgical results. However, the transverse area of the spinal cord at the level of maximum compression was a better prognostic indicator.