[in Japanese]

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  Objective : To investigate the incidence of perioperative complications associated with lumbar laminectomy performed microscopically using the spinous process-splitting technique for degenerative lumbar canal stenosis.
  Methods : We retrospectively reviewed 250 consecutive patients (131 men and 119 women ; mean age 68.4 years, range 44-90 years) treated at our institute between 2006 and 2014. To assess the risk factors for unintended dural tear, which is the most common complication, we analyzed patient characteristics and surgeons’ experience. We also reviewed all the video records of the cases with incidental durotomy to identify dangerous locations and causative maneuvers for dural tear.
  Results : Of the 250 patients, 35 (14%) had more than one complication during surgery or within three months after surgery.
  Unintended dural tear occurred in 20 cases (8%). Moreover, we observed the following complications : two nerve root injuries, two wrong-level surgeries, one postoperative hematoma, six postoperative CSF collection, and four surgical site infections ; however, there was no severe deficit or mortality. There was no significant difference in age, sex, and number of treated levels between the patients with and without dural tear. Moreover, the surgeon’s experience did not markedly influence the incidence of dural tear. Dural tear frequently occurred during detaching or punching procedures at the medial aspect of the zygapophysial joint.
  Conclusion : The overall complication rate of microscopic lumbar laminectomy for degenerative lumbar canal stenosis was 14%, with no permanent deficit and mortality. The incidence of dural tear (8%) was the highest of all the complications. Great care should be taken to avoid dural tear, especially when using a dissector or Kerrison punch at the medial aspect of the facet joint.

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  Acute, progressive paralysis or bladder and bowel disturbance may occur with acute spinal epidural hematoma, but in some cases, the symptom spontaneously resolve. In this study, the clinical characteristics of acute spinal epidural hematoma were clarified, and the indications for and timing of surgery were investigated. Among the reported cases in Japan over a period of about 30 years until 2013, cases without paralysis or trauma, those with no epidural block or catheterization, and those involving the lumbar spine were excluded, and then, 11 factors that contributed to treatment outcomes were identified. One hundred twenty-one cases (8 of our own) were then carefully selected, including 62 treated conservatively (non-operative treatment) and 59 treated surgically. Univariate and multiple logistic regression analyses were conducted. Among the conservative treatment cases, (1) no anticoagulant therapy, (2) paralysis severity of C or D in Frankel classification, (3) and time of the start of recovery (within 15 hours) were the factors associated with spontaneous recovery. Chances for complete recovery from severe paralysis of severity A or B were significantly higher in patients who underwent surgery within 24 hours. We consider the period is the appropriate decision-making time to switch to surgical treatment. In this disease, signs of recovery should be observed for up to 15 hours from the onset of paralysis. If the possibility of non-surgical complete recovery is low, then a switch to surgery should be made within 24 hours.

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  Object : We examined 50 cases of cervical spondylotic myelopathy with some instability and assessed outcomes of expansive laminoplasty and/or posterior decompression and fixation. We compared the outcomes of the operative treatments and examined operative indications and the problems in each operation.
  Materials and Methods : We retrospectively evaluated 20 cases of expansive laminoplasty with ceramic spacers and 30 cases of one-stage posterior decompression and posterior lateral fixation (PDLF) with instrumentation, according to the Japanese Orthopedics Association (JOA) score for neurological symptoms. To assess the alignment changes and mobile range, the C2-7 Cobb angle and C2-7 sagittal vertical axis were investigated.
  Results : The expansive laminoplasty cases showed 75% improvement in neurological symptoms and 50% improvement in the JOA score (recovery rate [RR]). One-stage PDLF cases demonstrated 93% improvement in neurological symptoms and 67.5% RR. The improvements in neurological symptoms and RR were higher in the one-stage PDLF cases than in the PD cases. The C2-7 Cobb angle was maintained in the one-stage PDLF cases. In the cases where fixation was performed three or more times, range of motion was decreased after surgery.
  Conclusions : In the cases with spondylotic change in three or more levels and instability, additional fixation (one-stage PDLF) at the appropriate level improved the results. Decreased range of motion after fixation remains a problem, which causes complaints and induces new lesions at the adjacent level.

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