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Vincent Traynelis

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Pleomorphic xanthoastrocytoma of the spinal cord

Case report

Masaya Nakamura, Kazuhiro Chiba, Morio Matsumoto, Eiji Ikeda, and Yoshiaki Toyama

✓ The authors present clinical, radiological, and pathological features in a patient with a pleomorphic xanthoastrocytoma (PXA) of the spinal cord. To their knowledge, this is only the second report of a spinal cord PXA. In addition they perform a review of the literature on these tumors.

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Solitary cervical fibrous tumor

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Yukihiko Obara, Morio Matsumoto, Kazuhiro Chiba, Hiroo Yabe, Yoshiaki Toyama, and Makio Mukai

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Relationship between alignment of upper and lower cervical spine in asymptomatic individuals

Kenya Nojiri, Morio Matsumoto, Kazuhiro Chiba, Hirofumi Maruiwa, Masaya Nakamura, Takashi Nishizawa, and Yoshiaki Toyama


The aim of this study was to establish standard values for the normal alignment of the upper cervical spine and to clarify its relationship with the lower cervical spine in terms of alignment.


Three hundred thirteen asymptomatic volunteers (155 men and 158 women) participated in this study. Lateral radiographs were obtained with the neck in neutral position, and the angles formed by the occiput (Oc) and the axis, the atlas and the axis, and C-2 to C-7 were measured. The mean Oc—C2 angle was 14.5 ± 8° in men and 16 ± 8.5° in women; the mean C1–2 angle was 26.5 ± 7° and 28.9 ± 6.7°, respectively; and the mean C2–7 angle was 16.2 ± 12.9° and 10.5 ± 10.3°, respectively. Although weak, statistically significant negative correlation was observed between Oc—C2 and C2–7 angles (r = −0.31 in men and −0.37 in women), and between C1–2 and C2–7 angles (r = −0.22 in men and −0.22 in women). The correlation coefficient between the Oc—C2 and C2–7 angles was greater than that between the C1–2 and C2–7 angles.


Such relationships between alignment of the upper and lower cervical spines should be taken into consideration when performing occipitocervical fusion.

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Infantile spinal cord meningioma

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Masahiko Watanabe, Kazuhiro Chiba, Morio Matsumoto, Hirofumi Maruiwa, Yoshikazu Fujimura, and Yoshiaki Toyama

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Surgical management of idiopathic spinal cord herniation: a review of nine cases treated by the enlargement of the dural defect

Masahiko Watanabe, Kazuhiro Chiba, Morio Matsumoto, Hirofumi Maruiwa, Yoshikazu Fujimura, and Yoshiaki Toyama

Object. Spinal cord herniation is a rare cause of progressive myelopathy and can be corrected surgically. In most previous reports, closure of the dural defect was the recommended procedure. The object of this paper is to describe a new procedure in which spinal cord constriction is released by enlarging the hiatus; additionally the postoperative results will be discussed.

Methods. In nine patients with spinal cord herniation, enlargement of the dural defect was performed. In eight patients, neurological deficits resolved immediately after surgery. In one patient with a severe preoperative neurological deficit whose spinal cord herniated massively, deterioration occurred postoperatively. To date, no recurrence of herniation has been observed.

Conclusions. The goals of surgery are to reduce the herniation, return the spinal cord to the normal position, and prevent the recurrence of herniation. The use of sutures to close the dural defect has been the method of choice to date. The surgical space in front of the spinal cord, however, is insufficient to accommodate this procedure safely. Because symptoms are caused by the constriction of the spinal cord at the hiatus, surgical expansion of the hiatus allows the goals of surgery to be achieved. This procedure, which is technically easier and less invasive with regard to the vulnerable spinal cord than the closure of the dural defect, could be a viable alternative for the treatment of this rare disease.

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Use of a titanium mesh cage for posterior atlantoaxial arthrodesis

Technical note

Morio Matsumoto, Kazuhiro Chiba, Takashi Tsuji, Hirofumi Maruiwa, Yoshiaki Toyama, and Jun Ogawa

✓ The authors placed titanium mesh cages to achieve posterior atlantoaxial fixation in five patients with atlantoaxial instability caused by rheumatoid arthritis or os odontoideum. A mesh cage packed with autologous cancellous bone was placed between the C-1 posterior arch and the C-2 lamina and was tightly connected with titanium wires. Combined with the use of transarticular screws, this procedure provided very rigid fixation. Solid fusion was achieved in all patients without major complications. The advantages of this method include more stable fixation, better control of the atlantoaxial fixation angle, and reduced donor-site morbidity compared with a conventional atlantoaxial arthrodesis in which an autologous iliac crest graft is used.

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Usefulness of neurological examination for diagnosis of the affected level in patients with cervical compressive myelopathy: prospective comparative study with radiological evaluation

Morio Matsumoto, Masayuki Ishikawa, Ken Ishii, Takashi Nishizawa, Hirofumi Maruiwa, Masaya Nakamura, Kazuhiro Chiba, and Yoshiaki Toyama

Object. Although neurological examination is the key step to reaching a correct diagnosis of cervical compressive myelopathy (CCM), the accuracy of diagnosis of the affected spinal level for CCM has not yet been tested.

Methods. The authors conducted a prospective study to elucidate how accurately the affected intervertebral level can be determined and decompressed based on neurological examination. Fifty patients who underwent successful decompressive surgery for cervical myelopathy caused by single-level disc herniation or spondylosis were included in this study (38 men and 12 women, mean age 60 years). Three board-certified spine surgeons participated in establishing the neurological diagnoses. One of the three surgeons made a diagnosis of CCM, and the other two conducted the neurological examination including deep tendon reflex, pinprick response, muscle weakness, and numbness in the hand only, knowing that the patient had CCM, and established the neurological-level diagnosis. A single intervertebral level responsible for patient's symptoms was determined concordantly based on magnetic resonance imaging and myelography findings by two spine surgeons, and this served as the standard. Agreement between neurological and neuroimaging/radiological level diagnoses was determined. The rate of agreement between neurological and neuroimaging diagnosis was 66%. Among the neurological tests, patient-perceived location of numbness in the hands was the most useful for establishing the affected level. For the other three tests the agreement rate was lower than 50% and thus each individual test may not be reliable for diagnosing the affected level.

Conclusions. The results of this study suggested that neurological examination in patients with CCM is moderately accurate and reliable for determining the neurological level of disease.

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Impact of sagittal spinopelvic alignment on clinical outcomes after decompression surgery for lumbar spinal canal stenosis without coronal imbalance

Tomohiro Hikata, Kota Watanabe, Nobuyuki Fujita, Akio Iwanami, Naobumi Hosogane, Ken Ishii, Masaya Nakamura, Yoshiaki Toyama, and Morio Matsumoto


The object of this study was to investigate correlations between sagittal spinopelvic alignment and improvements in clinical and quality-of-life (QOL) outcomes after lumbar decompression surgery for lumbar spinal canal stenosis (LCS) without coronal imbalance.


The authors retrospectively reviewed data from consecutive patients treated for LCS with decompression surgery in the period from 2009 through 2011. They examined correlations between preoperative or postoperative sagittal vertical axis (SVA) and radiological parameters, clinical outcomes, and health-related (HR)QOL scores in patients divided according to SVA. Clinical outcomes were assessed according to Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores. Health-related QOL was evaluated using the Roland-Morris Disability Questionnaire (RMDQ) and the JOA Back Pain Evaluation Questionnaire (JOABPEQ).


One hundred nine patients were eligible for inclusion in the study. Compared to patients with normal sagittal alignment prior to surgery (Group A: SVA < 50 mm), those with preoperative sagittal imbalance (Group B: SVA ≥ 50 mm) had significantly smaller lumbar lordosis and thoracic kyphosis angles and larger pelvic tilt. In Group B, there was a significant decrease in postoperative SVA compared with the preoperative SVA (76.3 ± 29.7 mm vs 54.3 ± 39.8 mm, p = 0.004). The patients in Group B with severe preoperative sagittal imbalance (SVA > 80 mm) had residual sagittal imbalance after surgery (82.8 ± 41.6 mm). There were no significant differences in clinical and HRQOL outcomes between Groups A and B. Compared to patients with normal postoperative SVA (Group C: SVA < 50 mm), patients with a postoperative SVA ≥ 50 mm (Group D) had significantly lower JOABPEQ scores, both preoperative and postoperative, for walking ability (preop: 36.6 ± 26.3 vs 22.7 ± 26.0, p = 0.038, respectively; postop: 71.1 ± 30.4 vs 42.5 ± 29.6, p < 0.001) and social functioning (preop: 38.7 ± 18.5 vs 30.2 ± 16.7, p = 0.045; postop: 67.0 ± 25.8 vs 49.6 ± 20.0, p = 0.001), as well as significantly higher postoperative RMDQ (4.9 ± 5.2 vs 7.9 ± 5.7, p = 0.015) and VAS scores for low-back pain (2.68 ± 2.69 vs 3.94 ± 2.59, p = 0.039).


Preoperative sagittal balance was not significantly correlated with clinical or HRQOL outcomes after decompression surgery in LCS patients without coronal imbalance. Decompression surgery improved the SVA value in patients with preoperative sagittal imbalance; however, the patients with severe preoperative sagittal imbalance (SVA > 80 mm) had residual imbalance after decompression surgery. Both clinical and HRQOL outcomes were negatively affected by postoperative residual sagittal imbalance.

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Surgical correction of severe cervical kyphosis in patients with neurofibromatosis Type 1

Report of 3 cases

Soya Kawabata, Kota Watanabe, Naobumi Hosogane, Ken Ishii, Masaya Nakamura, Yoshiaki Toyama, and Morio Matsumoto

Severe cervical kyphosis requiring surgical treatment is rare in patients with neurofibromatosis Type 1 (NF1). When it occurs, however, dystrophic changes in the vertebrae make surgical correction and fusion of the deformity extremely difficult.

The authors report on 3 cases of severe cervical kyphosis associated with NF1 that were successfully treated with combined anterior and posterior correction and fusion. All patients underwent halo-gravity traction for approximately 1 month prior to surgery to correct the deformity gradually. Posterior correction and fusion were performed with segmental spinal instrumentation consisting of lateral mass screws, lamina screws, pedicle screws, and polyethylene tape for sublaminar wiring. Anterior spinal fusion was performed using a fibula strut to induce solid bone fusion. All patients used a halo vest for postoperative external fixation.

Preoperative CT scans showed dystrophic cervical spine changes, and MR images demonstrated extensive neurofibromas outside the cervical spine in all 3 patients. The preoperative kyphotic angles were as follows: Case 1, 140°; Case 2, 81°; and Case 3, 72°; after halo-gravity traction, the kyphosis angles improved to 50°, 55°, and 51°, respectively; and after surgery, they were 50°, 15°, and 27°, respectively. Solid bone union was observed in all patients at the latest follow-up. All three patients experienced postoperative complications consisting of superficial infection, severe pneumonia, and partial dislocation of the distal fibula graft after removing the halo vest, in one patient each.

Although dystrophic cervical vertebral changes in these patients with NF1 complicated the correction of severe cervical kyphosis, the use of preoperative halo-gravity traction, a combination of spinal instrumentations, an anterior strut bone graft, and postoperative halo-vest fixation made it possible to correct the kyphosis, maintain the correction, and achieve solid bone fusion.