Background : Open-door cervical laminoplasty requires devices such as stay sutures (SS), laminar spacers (LS), and titanium mini-plates (TM) to keep the elevated lamina open. However, the significance and differences in the effects of each of these devices remain unclear. This study aimed at investigating the role of these devices, using a 3-dimensional finite element (FE) model.

  Methods : An FE bone model of the fifth cervical vertebra was constructed. Its lamina was elevated by guttering at the hinge site, simulating an open-door technique (G model). SS, LS, and TM were added to the G model, simulating laminoplasty with SS (SS model), LS (LS model), and TM (TM model), respectively. Compression loading force was applied to the elevated lamina in 2 directions of the horizontal plane, and the stress distribution response was analyzed.

  Results : The peak Mises stress which integrates the stresses in multiple directions into a unified vector was concentrated at the hinge region in the G and SS model. In the LS and TM model, the peak Mises stresses were observed in the connecting regions between the LS and the lateral mass, and the TM and the elevated lamina, respectively. The Mises stress in the hinge region was minimal in the LS model. Moreover, the bony peak Mises stress and the maximum deformation were minimal in the LS model.

  Conclusions : This stress distribution study clearly demonstrated that the placement of artificial implants such as LS and TM determined the stress concentration at the hinge region during laminoplasty with SS. The results of deformation studies showed that LS was best for stabilizing the elevated lamina. Based on this analysis, we suppose that the use of LS for stabilization of the hinge region might yield favorable results over other devices in open-door laminoplasty.

  Introduction : Misdiagnosis and/or inadequate treatment for lumbar foraminal stenosis (LFS) are the most common causes of failed back surgery. While several surgical procedures have been reported, the best surgical treatment remains controversial. We reported use of microsurgical medial/lateral fenestration to treat patients with LFS, and describe our early results.

  Material and Methods : In our institute, 81 patients (10.7% of 752 of all patients with lumbar degenerative disease) had previously undergone LFS. Our diagnostic criteria for LFS included the following : clinical symptoms such as severe radicular symptoms (pain or paresthesia) of the affected nerve root area, a positive Kemp's sign, and radiological evidence. We followed 28 patients for a minimum of 3 years. Nineteen patients had undergone microsurgical medial fenestration, and 9 patients were treated with microsurgical lateral fenestration. The study group comprised 17 men and 11 women, with an average age at surgery of 62.3 years and a mean follow-up period of 45.5 months. Our clinical results were evaluated using the Japanese Orthopedic Association (JOA) scoring system. Pre-and postoperative plain radiographs, computed tomography, and magnetic resonance imaging were used in the evaluation of radiographic findings. We analyzed the cause of poor results with residual or recurrent symptoms.

  Results : The affected nerve root was at the L3 and L4 levels in 1 patient, and at the L5 level in 26 patients. There were no intraoperative surgical complications. The JOA scores showed significant improvement at the final follow up (p<0.05). No patients manifested postoperative spinal instability or malalignment.

  Conclusions : Microsurgical medial and lateral fenestration are less invasive surgical techniques that do not result in spinal instability or malalignment and yield excellent clinical outcomes. Coexisting diseases (excluding lumbar disease) can have a role in residual or relapsing symptoms after surgery.

  When operating on spinal ependymomas, careful dissection of tumors in the ventral attachment is important because the tumor-feeding arteries and the central vessels of the cord, both of which branch from the anterior spinal artery, are located close to the anterior median septum (AMS), which is an extension of the pia in the cord. In this study, we examined the clinical features of tumor attachment to the AMS.

  We divided 10 patients who underwent total removal of spinal ependymomas into 2 groups based on the ventral attachment of their tumors. In Group A (n=5), the tumor was attached to the AMS, and in Group B (n=5), it was not attached to the AMS. We recorded the patients' modified McCormick grades at the time of admission, immediately, and 4 weeks after surgery. Pre-and postoperative changes in their functional status were evaluated by a deterioration/amelioration scoring system where 0=no change of grade, −1,−2=deterioration by 1 or 2 grades, and +1=improvement by 1 grade. We compared the scores recorded for Group A and B patients just after and 4 weeks after surgery. In addition, we compared the motor evoked potentials (MEPs), preoperative magnetic resonance imaging (MRI) results (proportion of the tumor to the cord, intratumoral cyst, and syrinx), and pathological findings (anaplastic changes and MIB-1 index) in the 2 groups.

  In group A, tight adhesion of the tumor to the AMS rendered selective division of the feeding arteries difficult. The mean deterioration/amelioration scores immediately and 4 weeks after surgery were −1.2 (range 0 to −2) and −0.6 (range +1 to −2), respectively in Group A. They were −0.8 (range 0 to −2) and +0.2 (range +1 to −1) respectively in Group B. Four weeks after surgery, one patient of Group A was scored −2, whereas no patient of Group B had a score of −2. Both groups, manifested decreases in MEP amplitudes. There were no specific MRI and pathological findings pertinent to the pattern of a attachment to the septum.

  Tumors with adhesion to the AMS raise the risks of damage to the central vessels, tend to produce deterioration, and result in delayed postoperative recovery. Careful dissection that is based on an understanding of the anatomical relationship between the AMS and the central vessels and feeding arteries facilitates the safe detachment of these tumors from the AMS.

  Objective : Aging shift of Japanese population has resulted in increase in elderly patients with cervical spinal cord injury without bone injury. Outcomes in conservative and surgical treatments are assisted to evaluate efficacy of operative interventions.

  Methods : From January 2008 to April 2012, 207 cases with cervical spine trauma were encountered at the emergency department of our institute ; of these, 98 were cases of elderly patients (over 65 years of age).

  Results : Out of the 98 patients, 25 patients (12.1% ; 16 men and 9 women), with an average age of 74.4 years (66-85 years) at the time of injury, were diagnosed with cervical spinal cord injury without bone injury. Minimal trauma, including falling, was the most frequent cause of injury. These patients had either cervical canal stenosis with spondylosis (19 cases) or ossification of the posterior longitudinal ligament (OPLL, 6 cases). Seven patients presented with gait impairment at the time of injury. The injured disk level was C3/4 in 14 cases, C4/5 in 6 cases, and C5/6 in 5 cases. Frankel classification grading of the patients (on admission/at the time of discharge) was as follows : A, 3/3 ; B, 3/0 ; C, 12/4 ; D, 7/17 ; and E, 0/1. Eleven patients received conservative therapy, and 14 patients underwent surgical treatment (anterior cervical discectomy and fusion in 2 ; laminoplasty in 12). After discharge, 5 patients returned home, 19 patients changed hospital, and 1 patient died.

  Conclusion : This study suggests that surgical treatment should be considered to prevent spinal cord injury in elderly patients with cervical spondylosis or OPLL exhibiting gait impairment. However, the indication of surgery should be carefully judged after considering the general condition and motivation of each elderly patient.

  A 73-year-old man complained of severe back pain and increased difficulty in walking. A contrast-enhanced computed tomography (CT) scan revealed a lobular dilatation of the abdominal aorta, which had eroded into the anterior part of the adjacent vertebral bodies at T12 and L1. T1-weighted magnetic resonance (MR) images revealed a hypointense signal at the T12/L1 level. The diagnosis was pyogenic vertebral osteomyelitis of the thoracolumbar spine associated with an infected abdominal aortic aneurysm. Following antibiotic therapy for several weeks, the patient underwent aortic stenting and bypass surgery with an artificial graft for the visceral branches. After vascular surgery, the aortic aneurysm disappeared on the contrast-enhanced CT scans. Although the infection had resolved, the patient's back pain persisted because of osteolytic changes in the T12 and L1 vertebral bodies. Thereafter, he was transferred to our spinal surgery unit. We performed anterior reconstruction of the thoracolumbar spine and one-stage posterior spinal fixation. The necrotic disc and the adjacent infected vertebrae were exposed via an extrapleural approach and were excised subtotally. Two fibular bone grafts were used to reconstruct the spinal column. Posterior spinal fixation was performed from T10 to L3 using the cortical bone trajectory technique. Postoperatively, the patient experienced a significant reduction in pain and no perioperative complications were noted.

  Coexistence of pyogenic vertebral spondylitis and an infected abdominal aortic aneurysm is rare ; however, this condition could be life threatening if not treated effectively, and warrants appropriate diagnosis by the spinal surgeons in order to ensure adequate management.

  For the spine, anterior column support is more important than posterior column support. Two-thirds of the spinal support force is derived from the anterior column. Destruction of the anterior support, which is most frequently due to disc degeneration, can cause a variety of degenerative disorders of the lumbar spine.

  Mini-ALIF, or minimally invasive anterior lumbar interbody fusion, is a surgical method used to treat the spine. The technique of this surgery is as follows.

  1) Under general anesthesia, the patient is placed in the right lateral position.

  2) A skin incision is made in the supra-iliac crest area.

  3) The psoas major muscle is accessed retroperitoneally.

  4) The desired disc is accessed by retracting the psoas major muscle and the disc level is confirmed through fluoroscopy.

  5) A discectomy is performed until the posterior ligament can be seen.

  6) A distractor is inserted into the disc space and rotated 90°to regain the appropriate disc. height and the correct alignment that have been lost because of scoliosis or spondylolisthesis.

  7) Two artificial discs are inserted into the disc level.

  The patient is allowed to walk the day after surgery. The average hospital stay is 10 days.

  Approximately 6 months after surgery, bony fusion is confirmed by performing dynamic radiography and computed tomographic scanning.