Kiyoshi Hirabayashi

Operative results and postoperative progression of ossification among patients with ossification of cervical posterior longitudinal ligament.

Although the pathogenesis of ossification of the cervical posterior longitudinal ligament (OPLL) has not yet been clarified, it has come to be widely recognized that severe cervical myelopathy or radiculopathy is caused by OPLL. Fifty-three cases who were operated on for OPLL with myelopathy or radiculopathy in our clinic over the past 16 years were followed up. A recovery rate of approximately 70% was observed. Postoperative progressions of the ossification were observed among 75% of the cases of continuous and mixed type but seldom among those with segmental and other types. As causative factors for these postoperative progressions of the ossification, the authors would like to advocate biological, structural, and mobility-related elements. We concluded that in the ossified stage it is desirable to apply anterior decompression for the segmental and other type, posterior decompression for the continuous and mixed type, and, if necessary, two-stage combined decompression for the mixed type.

Expansive Open-door Laminoplasty for Cervical Spinal Stenotic Myelopathy

Although the operative results have been improving since the air drill was introduced for cervical laminectomy instead of an ordinary rongeur, post-laminectomy complications, such as postoperative fragility of the cervical spine to acute neck trauma, posterior spur formation at the vertebral body, and malalignment of the lateral curvature have still remained as unsolved problems. In order to avoid these disadvantages, a new surgical technique called “expansive open-door laminoplasty” was devised by the author in 1977, which is relatively easier, safer, and better than the ordinary laminectomy from the standpoint of structural mechanics of the cervical spine. The operative procedure is described in detail. Operative results in the patients with cervical OPLL, spondylosis, and canal stenosis were satisfactory, and optimal widening of the AP diameter of the spinal canal is considered to be over 4 mm. From this procedure a bilateral, open-door laminoplasty has been devised for extensive exploration at the intradural space.

Long-term outcomes of standard discectomy for lumbar disc herniation: A follow-up study of more than 10 years

Study Design. A retrospective analysis of the long-term outcomes of standard discectomy for lumbar disc herniation. Objectives. To investigate the long-term outcomes of standard discectomy to address postoperative problems, including residual low back pain and recurrent herniation. Summary of Background Data. Most previous investigators found that favorable outcomes of standard discectomy were maintained for the long-term postoperative period. Although they observed postoperative complications such as residual low back pain and recurrent herniation, detailed analyses of these results have not been conducted. Methods. The long-term follow-up results in patients who were observed for a minimum of 10 years after standard discectomy were evaluated by using the Japanese Orthopedic Association scoring system through direct examinations and questionnaires. Radiography also was used in patients who agreed to visit the hospital, and findings were compared with those on preoperative radiographs. Results. The average recovery rate calculated by using Japanese Orthopedic Association scores was 73.5 ± 21.7%. Even though residual low back pain was found in 74.6% of the patients, only 12.7% had severe low back pain. The majority of the patients with severe low back pain were under 35 years of age at the time of operation, with preoperative advanced disc degeneration. The final Japanese Orthopedic Association scores in the patients with decreased disc height were significantly lower than those in patients with no decrease. However, the disc height of patients with a recurrent herniation was preserved. Conclusion. The long-term outcome of standard discectomy in this series was favorable. Although patients with preserved disc height generally had favorable results, the risk of recurrent disc herniation was high in this population.

Segmental motor paralysis after expansive open-door laminoplasty

Study Design. A retrospective study was conducted to investigate patients in whom segmental motor paralysis developed after expansive open-door laminoplasty for cervical myelopathy. Objective. To propose the involvement of the spinal cord as a possible mechanism in the development of segmental motor paralysis. Summary of Background Data. Segmental motor paralysis is seen occasionally in patients who undergo expansive open-door laminoplasty for cervical myelopathy, and has long been attributed to nerve root lesions caused by either traumatic surgical techniques or a tethering effect induced by excessive posterior shift of the spinal cord after decompression. Involvement of spinal cord pathology is not suggested in the English literature. Methods. The study group consisted of 15 patients (11 men and 4 women) in whom postoperative segmental motor paralysis developed after expansive open-door laminoplasty during a minimum follow-up of 2 years. Their average age at the time of surgery was 56 years. Characteristics of the paralysis, clinical symptoms, recovery rates calculated using pre- and postoperative Japanese Orthopedic Association scores, and radiographic findings including pre- and postoperative magnetic resonance images were analyzed retrospectively and compared with those of 126 patients without segmental paralysis who underwent expansive open-door laminoplasty. Results. The paralysis occurred mainly, but not only, at C5, and eight patients had multilevel involvements predominantly in the hinge side, whereas two patients had paralysis on both sides. The paralysis had developed after an average of 4.6 days. Of the 15 patients, 14 reported severe numbness or dysesthesia in their hands before surgery, and their average recovery rate for upper extremity sensory disturbance was lower than for those without paralysis. Postoperative magnetic resonance imaging showed the presence of a T2 high-signal intensity zone in the spinal cord of all the patients. The level of such abnormal signal areas corresponded to the level of paralyzed segments in 10 of the 15 patients. Paralysis resolved completely in 11 patients. Conclusions. Delayed onset of paralysis, dysesthesiain the upper extremities, and the presence of T2 high-signal intensity zones suggest that a certain impairment in the gray matter of the spinal cord may play an important role in the development of postoperative segmental motor paralysis.

Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament.

Laminectomy, which had long been used for treatment of cervical spondylotic myelopathy, including ossification of the longitudinal ligament in the cervical spine, had numerous complications such as postoperative malalignment of the cervical spine and vulnerability of the spinal cord caused by total removal of the posterior structures. In 1977 Hirabayashi devised an open door expansive laminoplasty, which is a relatively easier and safer procedure than laminectomy, that eliminated such problems by preserving the posterior elements. The decompression effect of the expansive laminoplasty against a compressed spinal cord is comparable with that of laminectomy and anterior decompression followed by fusion, whereas the expansive laminoplasty has no structural problems and adverse effects on adjacent disc levels that often are associated with anterior decompression followed by fusion. Average recovery rate of expansive laminoplasty for cervical spondylotic myelopathy has been reported to be approximately 60% (Japanese Orthopaedic Association score) and with long term stability. At present, authors consider all patients with cervical spondylotic myelopathy candidates for expansive laminoplasty except for those having preoperative kyphosis and single level lesion without canal stenosis. Two remaining problems of expansive laminoplasty to be solved are prevention of C5,C6 radicular pain and/or paresis, the most frequent complication that occurs in approximately 5% to 10% of the patients, although most complications resolve spontaneously within 2 years, and correction of nonlordotic alignment to lordosis which are essential for posterior decompression effect of expansive laminoplasty by allowing the spinal cord to shift dorsally.

Short-term complications and long-term results of expansive open-door laminoplasty for cervical stenotic myelopathy

BACKGROUND CONTEXT Laminoplasty has been reported to achieve good operative results for treatment of cervical stenotic myelopathy. However, long-term results and prognostic factors have not been well documented. Among postoperative complications, weakness of the shoulder girdle muscles has been reported as a particular complication of laminoplasty, but the cause is still poorly understood. PURPOSE Our aim was to clarify the short-term complications and long-term operative results after unilateral open-door laminoplasty and to identify the predictors for operative outcome. STUDY DESIGN We retrospectively reviewed short-term complications and long-term operative results associated with cervical stenotic myelopathy treated by unilateral open-door laminoplasty. PATIENT SAMPLE There were 162 men and 42 women with an average age of 57 years who were treated by unilateral open-door laminoplasty in the two institutions. Pathogenesis of myelopathy was cervical spondylosis in 88 patients, cervical disk herniation with a narrow spinal canal in 10, and ossification of the posterior longitudinal ligament in 106. OUTCOME MEASURES Postoperative complications and their outcomes were examined clinically in 204 patients, and causes of motor paresis were sought with postoperative computed tomography after myelography. Postoperative improvement of clinical symptoms was assessed by recovery rate calculated with the scores of the Japanese Orthopaedic Scoring System in 80 patients. METHODS The occurrence rate of short-term postoperative complications, causes of motor paresis, and their outcomes were reviewed in 204 patients. Clinical condition was assessed with the Japanese Orthopaedic Scoring System, recovery rate was calculated with the score, and prognostic factors for outcome were studied in 80 patients who were followed up for 5 years or longer (average, 8 years; range, 5-17 years). RESULTS Occurrence rate of complications, such as muscle weakness, deep infection, closure of opened laminae, and others, was 10.8%. Muscle weakness was observed in 7.8% of the patients. However, this rate decreased in recent years. The cause of motor paresis is not known with certainty, but it may be secondary to operative trauma, posterior shift of the spinal cord, or to displacement of the lamina in the hinge side. Recovery rate of clinical symptoms was 62.1% at the final follow-up. Rates were 63.6% for cervical spondylosis, 87.1% for cervical disk herniation, and 61.3% for ossification of the posterior longitudinal ligament. There was no significant difference between pathologies. Patient age younger than 60 years at the time of operation and less than 1 years duration of symptoms before surgery were significantly associated with recovery rate of clinical symptoms. Recovery rate was not correlated with either preoperative function judged by the Japanese Orthopaedic Association score or spinal sagittal diameter. CONCLUSIONS The main cause of postoperative motor paresis of upper extremities is thought to be operative trauma, resulting from such procedures as air-drill and Kerrison rongeur handling. Short-term complications may decrease with the use of nontraumatic procedures. Better operative outcomes may be achieved with careful operative procedures and early operative treatment in the patients with myelopathy.

Idiopathic spinal cord herniation: Report of two cases and review of the literature

The authors experienced unique cases of spinal cord herniation. Only eight cases of spinal cord herniation have been reported formerly. The authors report two cases of spinal cord herniation accompanied with double structure of dura mater (duplicated dura mater). The causes of their condition are discussed in this report.

Predictability of operative results of cervical compression myelopathy based on preoperative computed tomographic myelography

The transverse area and flattening ratio of the spinal cord were determined with preoperative computed tomographic myelography in 103 patients with cervical compression myelopathy: cervical spondylotic myelopathy (n = 44); ossification of the posterior longitudinal ligament (n = 39); and cervical disc herniation (n = 20). With these values and other clinical items (eg, age, duration of symptoms, preoperative severity), a linear model to predict postoperative recovery was attempted by multiple regression analysis. In cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament, the transverse area of the spinal cord and the duration of symptoms were accepted as effective explanatory variables to predict recovery. In cervical disc herniation, regardless of the transverse area or duration, the recovery was good, and pathologic state was considered essentially different.

Treatment in fractures of the odontoid process

Fifty-eight cases of odontoid fractures treated at Keio University Hospital and affiliate hospitals from 1965 through 1985 were reviewed. Six patients under age 7 years (group A), were characterized as having epiphysiolysis. Among 52 patients over 8 years of age (group B), there were two Type I, 31 Type II and 19 Type III fractures. All cases in group A were treated conservatively by a plaster cast or a neck brace, and achieved bony union in 6 to 27 weeks. Five of 24 fractures in group B, treated conservatively, failed to unite. Nineteen cases of Type II and six cases of Type III were treated surgically. Transoral fusion was performed in six cases, internal fixation using a compression screw in ten, bone peg fixation in one, posterior fusion in eight, and posterior decompression in one. Two cases treated with transoral fusion and two with screw fixation failed to unite. We recommend conservative treatment of group A patients, Type I, and acute cases of Type III with minimal displacement in group B. Surgery should be performed in acute cases of Type II, Type III with significant displacement, and nonunion cases in Type II and Type III.

Multilevel cervical spondylosis : laminoplasty versus anterior decompression

Poor overall outcome and a high incidence of postoperative kyphosis and progressive myelopathy have driven surgeons away from decompressive laminectomy as a treatment for multilevel cervical spondylosis. Dr. Henry Bohiman advocates anterior decompression and fusion as the best approach to the pathopPoor overall outcome and a high incidence of postoperative kyphosis and progressive myelopathy have driven surgeons away from decompressive laminectomy as a treatment for multilevel cervical spondylosis. Dr. Henry Bohlman advocates anterior decompression and fusion as the best approach to the pathophysiology of this disorder, while Dr. Kiyoshi Hirabayashi believes that laminoplasty represents an excellent strategy for patients with degenerative disease, as well as those with ossification of the posterior longitudinal ligament.