Spinal cord injury (SCI) causes multiple dysfunctions including motor paresis, chronic pain, and incontinence, which severely impairs patients’ quality of life. However, partial injury is frequently followed by the substantial recovery of motor function. Revealing the mechanism of such spontaneous recovery will be helpful for the development of new treatments such as regenerative therapy, brain machine interfaces, and robot suit rehabilitation, among others. Recently, we developed an SCI model, which shows complete recovery of finger dexterity, in the macaque monkey. In this model, the lateral corticospinal tract, which directly connects the brain with spinal motoneurons, was selectively transected. Here, we reveal elements of the neural mechanism for motor recovery at different hierarchical levels of the central nervous system. These findings were made possible by investigating our novel monkey model.

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[in Japanese]

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  Objective : The number of spinal disorders operated on by neurosurgeons is increasing in our country. Although Japanese neurosurgeons perform spinal surgery in about 15 percent of their operations, this is still a low rate when compared to that in Western countries where neurosurgeons would perform in 70 percent of all neuro-operations. Little is known about the steps that lead to a patient with a spinal disorder being seen in a hospital and subsequently referred to the specialists. Investigating this process would help understanding of the consultation patterns leading to spinal surgery.
  Methods : This study focused on patients with spinal tumors, a rare disease. The authors utilized the medical records from 73 spinal tumor patients who underwent their first operation between April 2003 and March 2014.
  Results : For 67 out of the 73 patients, the facilities where they made the initial visit were identified. The clinic visited by the spinal tumor patients first includeds orthopedics (49.3%), neurosurgery (10.4%), internal medicine (9.0%), clinical neurology (3.0%) and bone-setting (7.5%). Almost half of the patients visited orthopedics, not neurosurgery, for the neurological symptoms. The authors compared the differences between the initial visit for cervical, thoracic and lumbar tumors. Orthopedics clinics were the initial department visited by approximately half of the patients for each type of spinal tumor.
  Conclusion : Although the present study was conducted at a single institution with data spanning only 11 years, it is comparable to similar studies performed all over the country. Large-scale data analysis will allow us to understand the consulting process and help improve public education of spinal tumors. Furthermore, this report could serve as a primer for the similar studies for spinal degenerative diseases. If the society is more informed about spinal diseases, patients are more likely to be seen by neurosurgery, and to receive proper treatment.

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  Objective : Intramedullary high signal intensity on T2-weighted magnetic resonance imaging is frequently observed in patients with cervical spondylotic myelopathy. This finding does not correlate with neurological recovery after surgery. Previous studies have illustrated that the apparent diffusion coefficient (ADC) map is more sensitive than T2-weighted imaging for detection of cervical compressive myelopathy. The present study examined the relationships between pre-operative ADC values and surgical outcome of cervical compressive myelopathy.
  Materials and Methods : A total of 106 patients with cervical compressive myelopathy requiring decompression surgery were enrolled in this study. The mean age of patients was 63.5±14 years, and mean symptom duration was 30.5±59 months. Presurgical appearances of the spinal cord on ADC maps and T2-weighted images were evaluated by an experienced spine surgeon. The relation between these radiological parameters and clinical findings was analyzed.
  Results : Eighty-seven patients (82%) showed T2 high intensity, and 66 patients (62%) showed increased ADC values before surgery. Patients with T2 high intensity had significantly longer duration of symptoms. The mean durations of symptoms in patients with T2 high intensity and iso-intensity were 33.7±63 and 13.8±20 months, respectively. Similarly, patients with increased ADC values had longer duration of symptoms. The mean symptom durations in patients with and without increased ADC values were 38.2±70 months and 17.7±29 months, respectively. Patients with T2 high intensity had comparable recovery rates in JOA scores than did patients with iso-intensity. In contrast, patients with increased ADC values had significantly lower recovery rates. The mean recovery rates in patients with and without increased ADC values were 45.1%±27% and 57.0%±30%, respectively.
  Conclusion : Neurological recovery in patients with cervical compressive myelopathy may be predicted preoperatively using ADC values.

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  Objective : Tumors of the brachial plexus region are relatively rare. Preservation of neurological function and radical excision are important considerations in surgical treatment. The aim of this report is to present our experience in managing brachial plexus schwannoma.
  Method : Six cases of brachial plexus schwannoma were operated on at our hospital between 2007 and 2013. The mean patient age was 47 (38-53) years. Initial symptoms, radiological findings, surgical results were analyzed.
  Results : Common clinical presentations were hypoesthesia (66.7%), paresthesia (33.3%), and pain (33.3%). One patient demonstrated mild motor weakness. MRI showed hypo- and hyper-intensity on T1 and T2 weighted imaging, respectively, and both homogenous to heterogeneous enhancement. All tumors were microscopically excised under electrophysiological monitoring. Gross total removal was achieved in five cases, and subtotal removal in one. Transient worsening of hypoesthesia and motor weakness occurred in five and one cases, respectievely ; these worsened symptoms improved during the follow-up period in all cases. Postoperative MRI showed no remnant tumor in all but one case. No case showed recurrence or regrowth of the tumor in the follow-up period.
  Conclusion : Microscopic excision under electrophysiological monitoring minimizes neurological damage in brachial plexus schwannoma.

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  Pelvic insufficiency fractures (PIFs) are atraumatic fragility fractures due to osteoporosis. PIFs can be a source of lower back pain and referred symptoms in the buttocks, legs, and groin ; however, they are often unsuspected and overlooked in the clinically because of a low suspicion and the poor sensitivity of radiography.
  We report two cases of simultaneous PIFs that were difficult to recognize and diagnose because of the delay of pelvic diagnostic imaging. Both cases involved elderly female patients with a history of spinal surgery and severe osteoporosis with pain in the buttocks, legs, and groin. At first, we could not identify sacral lesions on spinal imaging. However, for prolonged symptoms, pelvic magnetic resonance imaging (MRI) and computerized tomography (CT) scans were obtained several weeks after admission, revealing sacral and pubic fractures that were treated conservatively.
  To avoid diagnostic delays and oversights, PIFs should be considered as a differential diagnosis in patients, especially in elderly women with osteoporosis who have sacral pain and symptoms in the legs and groin. Pelvic MRI and highly specific CT scans are recommended, as well as careful medical examination.

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  Adult lumbar degenerative scoliosis can be provoked by disc degeneration. Asymmetrical disc height loss leads to scoliosis. The mechanism underlying root pain is foraminal stenosis at the disc level of the most concave site. Mini-open anterior lumbar interbody fusion (Mini-ALIF) may be an appropriate, less invasive treatment for symptomatic adult scoliosis. We selected 30 patients (8 men, and 22 women) who had been treated by mini-ALIF. The treated level of the lumbar spine was L1/2 in 2 patients, L2/3 in 6 patients, L3/4 in 17 patients, and L4/5 in 22 patients. There was 1-level fusion in 17 patients, 2-level fusion in 10 patients, 3-level fusion in 2 patients, and 4-level fusion in 1 patient.
  Surgery was performed in the lateral position mostly with the right side down. The left retroperitoneal approach was selected for disc level exposure. By elevating the disc height using a distractor, cages were inserted one by one. The patients were ambulatory on the next day of this surgery using a soft lumbar corset. Postoperative results were satisfactory.
  The advantage of this surgery is not only the short incision but also the preservation of the entire posterior back muscles, joints, and bony structures that work as supportive dynamic elements of the lumbar spine.
  This clinical experience suggests that mini-ALIF is a promising surgical option for adult degenerative symptomatic lumbar scoliosis.

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