Takashi Kusakabe

Results of surgical treatment for thoracic myelopathy: minimum 2-year follow-up study in 132 patients

OBJECT Thoracic myelopathy is uncommon compared with cervical myelopathy. In this study, data obtained in patients with thoracic myelopathy caused by degenerative processes of the spine were retrospectively analyzed to clarify the surgical outcomes and to examine the various factors affecting the postoperative improvement. METHODS Between 1988 and 2002, 132 patients with thoracic myelopathy underwent surgery and a minimum 2-year observation period. Clinical data were collected from medical and operative records, and sagittal alignment of the spine was measured on radiographs. The patients were evaluated pre- and postoperatively using the modified Japanese Orthopaedic Association (JOA) scale (maximum score 11). The relationships among various factors affecting the preoperative severity of myelopathy and postoperative improvement were also examined. RESULTS The population consisted of 97 men (mean age at surgery was 58 years) and 35 women (mean age at surgery 62 years). Myelopathy was caused by ossification of the ligamentum flavum (OLF) in 73 patients, ossification of the posterior longitudinal ligament (OPLL) in 21, combined OLF-OPLL in 10, intervertebral disc herniation (IDH) in 15, posterior bone spur in 11, and OLF with IDH or posterior bone spur in one patient each. The surgical outcome was relatively good: a mean preoperative JOA score of 5.3 improved to a mean score of 7.8 at the last follow-up, 50 months on average after surgery. Thoracic myelopathy caused by OPLL, however, was associated with lower postoperative scores and recovery rates. In more than half of the patients the authors documented an increase of kyphosis of less than 2 degrees. CONCLUSIONS Patients with a shorter preoperative duration of symptoms and milder myelopathy experienced significantly better postoperative neurological conditions, which indicated that those who present earlier with fewer disabilities should be recommended to undergo surgery in time, although the surgical treatment for OPLL still involves many problems.

Dynamic Change of Dural Sac Cross-Sectional Area in Axial Loaded Magnetic Resonance Imaging Correlates With the Severity of Clinical Symptoms in Patients With Lumbar Spinal Canal Stenosis

Study Design. Cross-sectional registry and imaging cohort study. Objective. To examine whether the dural sac cross-sectional area (DCSA) in axial loaded magnetic resonance imaging (MRI) correlates with the severity of clinical symptoms in patients with lumbar spinal canal stenosis (LSCS). Summary of Background Data. Many studies have analyzed the relationship between DCSA on conventional MRI and the severity of symptoms in LSCS, but the link is still uncertain. Recently, axial loaded MRI, which can stimulate the spinal canal of patients in the upright position, has been developed. Axial loaded MRI demonstrates significant reduction of DCSA and provides valuable radiologic findings in the assessment of LSCS. However, there has been no study of the correlation between DCSA in axial loaded MRI and the severity of symptoms in LSCS. Methods. In 88 patients with LSCS, DCSA in conventional MRI, axial loaded MRI, and changes in the DCSA were determined at the single most constricted intervertebral level. The severity of symptoms was evaluated on the basis of the duration of symptoms, walking distance, visual analogue scale of leg pain/numbness, and Japanese Orthopaedic Association score. Spearman correlations of the DCSA in conventional MRI, axial loaded MRI, and changes in the DCSA with the severity of symptoms were analyzed. In addition, the severity of symptoms and DCSA in conventional and axial loaded MRI were compared, respectively, between patients with and without significant (>15 mm2) changes in the DCSA. Results. The DCSA in axial loaded MRI had good correlations with walking distance and Japanese Orthopaedic Association score (rs = 0.46 and 0.45, respectively; P < 0.001). In addition, the change in the DCSA significantly correlated to walking distance, visual analogue scale of leg numbness, and Japanese Orthopaedic Association score (rs = 0.59, 0.44, and 0.54, respectively; P < 0.001). Furthermore, the symptoms were significantly worse in patients with more than 15 mm2 change in the DCSA (P < 0.001). Axial loaded MRI, but not conventional MRI, showed a significantly smaller DCSA in patients with more than 15 mm2 change in the DCSA (P < 0.05). Conclusion. DCSA in axial loaded MRI significantly correlated with the severity of symptoms. Axial loaded MRI demonstrated that changes in the DCSA significantly correlated with the severity of symptoms, which conventional MRI could not detect. Thus, MRI with axial loading provides more valuable information than the conventional MRI for assessing patients with LSCS.

Does estrogen alter the mechanical properties of the anterior cruciate ligament?: An experimental study in rabbits

Background It is well known that anterior cruciate ligament (ACL) injuries are commoner in female athletes. Accordingly, we hypothesized that serum estrogen may play some role in this sex difference. We evaluated the relationship between serum estrogen levels and the mechanical properties of the ACL in rabbits. Animals and methods In 40 ovariectomized rabbits, the serum estrogen levels (SEL) were controlled by intramuscular injection of 17β-estradiol. The mean SEL in each rabbit was defined as the average of 5 determinations done at 1, 2, 3, 4 and 5 weeks after ovariectomy. The animals were divided into 4 groups according to the dose of estradiol administered (low, medium, high and control: L, M, H and C, respectively) and into 2 groups according to the mean SEL (high-SEL group and low-SEL group). The medial portions of ACL attached to both femur and tibia harvested at 5 weeks after ovariectomy were examined mechanically. Results The mean serum estrogen levels in groups C, L, M and H were 37, 50, 60 and 231 pg/mL. Statistically significant differences in the mean serum estrogen levels were seen among the 4 groups, except between groups L and M. Statistically significant differences were found between groups M and H in both the ultimate tensile stress and linear stiffness. In the comparison between 2 groups using the mean SEL value, both ultimate tensile stress and linear stiffness were lower in the high-SEL group. In all animals, a positive correlation was found between ultimate tensile stress and linear stiffness. Interpretation Our findings suggest that high SEL might be one of the factors in the multifactorial pathogenesis of ACL rupture.

Giant sacral schwannoma: A report of six cases

Abstract Sacral and presacral schwannomas are often found incidentally, because they present with vague symptoms or symptomless. Schwannoma occurring in this area occasionally presents with enormous dimensions, known as a giant schwannoma. The tumor removal is a surgical challenge due to the difficult approach and abundant vascularity. The aim of this study is to review cases of giant sacral schwannomas focusing the surgical management and outcome. Six patients with sacral and presacral schwannoma were treated surgically. The patients included two males and four females, and the mean age was 47.8 years. All patients experienced pain at the time of presentation. The tumors were classified as intraosseous type in one case, dumb-bell type in four cases, and retroperitoneal type in one case. The tumors were removed with a piecemeal subtotal excision in three patients, a partial excision in two patients, and enucleation in one patient. The surgeries were performed by the combination of an anterior and posterior approach in three patients, a posterior approach in two patients, and an anterior approach in one patient. The mean surgical time was 7.8 hrs, and the mean blood loss was 2572 g. The tumor recurred in one patient after the partial excision and was removed completely in a second surgery. No patient, including the patient who underwent the second surgery, presented with pain and obvious neurological deficit at the final follow-up. The surgical treatment of the giant sacral schwannoma with a piecemeal subtotal excision can achieve a good outcome, avoiding unnecessary neurological deficit.

Facet cyst haematoma in the lumbar spine: a report of four cases

We present 4 cases of facet cyst haematoma in the ligamentum flavum of the lumbar spine. All patients presented with a one-to-3-month history of back pain or numbness in the legs, and sudden neurological deterioration. One also developed cauda equina syndrome and another developed radiculopathy. In all cases, magnetic resonance imaging showed a mass with high signal intensity on both T1- and T2-weighted images. Facet arthrography and computed tomography revealed communication between the mass and the neighbouring facet joint. The haematomas were removed en bloc with the ligamentum flavum. They were surrounded by the ligament and contained degenerated and lacerated elastic fibres but no synovial lining cells. Facet cyst haematoma is so-named because of bleeding from tissue adjacent to the facet joint into a pre-existing facet cyst.

C1/2 facet cyst revealed by facet joint arthrography

1–14 Several terms have been used based on the histology and location of the cyst: synovial cyst at the craniovertebral or C1/2 junction, retrodental or periodontoid synovial cyst, and more generally atlantoaxial degenerative articular cyst. Different terms might indicate the same disorders, and confusion in the terminology makes it diffi cult to understand this entity. As we indicated in our large case series of juxtafacet cysts in the lumbar spine, 15 it is more important to prove a communication channel between the cyst and neighboring facet joint radiologically or histologically to clarify the pathogenesis of the cyst. Once the communication channel is revealed, the cyst formation should be closely related to degeneration of the facet joint with or without synovial cells in the cyst histologically. 15,16

Severe Facet Joint Arthrosis Caused C7/T1 Myelopathy: A Case Report

Cervical myelopathy is caused by degenerative processes of the spine including intervertebral disc herniation and posterior spur usually developing at C3/4 to C5/6. C7/T1 single level myelopathy is very rare because of the anatomical characteristics. Facet joint arthrosis can be a cause of cervical myelopathy but only a few cases have been reported. The authors report an extremely rare case of C7/T1 myelopathy caused by facet joint arthrosis. A 58-year-old male presented with hand and gait clumsiness. The radiological examinations revealed severe C7/T1 facet joint arthrosis with bony spur extending into the spinal canal, which compressed the spinal cord laterally. The T1 spinous process indicated nonunion of a “clay-shovelers” fracture, which suggested that his cervico-thoracic spine had been frequently moved, and thus severe arthrosis had occurred in the facet joints. A right hemilaminectomy of C7 and C7/T1 facetectomy with single level spinal fusion led to complete neurological improvement.

Lumbar radicular symptom caused by the cauda equina in ankylosing spondylitis: a case report

Abstract Lumbar radicular symptom is an unusual manifestation of neurological complications in patients with ankylosing spondylitis. Here, we report a case of lumbar radicular symptom caused by the cauda equina in ankylosing spondylitis.