We have provided an outline of the management of spinal arteriovenous malformations (SAVMs) on the basis of their angioarchitecture. Owing to the rarity of SAVMs, so far, only a few sophisticated studies have described their clinical features. Spinal cord vasculature is phylogenetically “old” as compared to the “new” neopallial one, and discrepancies remain to be solved in the histological and hemodynamic aspects. The clinical features of SAVMs should not be presumed to be identical to cerebral arteriovenous malformations. One should adopt different therapeutic strategies for each SAVM case depending upon its pathophysiology. This article emphasizes that a precise understanding of the SAVM angioarchitecture is the most important factor for enabling an appropriate management strategy. Moreover, because of their complexity and rarity, the management of patients with SAVM may require close collaborations between neurosurgeons, spinal surgeons, radiologists, neurologists, and pediatricians.

  Objectives : To describe a retrospectively reviewed cohort of patients who had undergone corpectomy and reconstruction of the thoracolumbar spine for multilevel continuous lesions and to discuss problems related to this procedure.

  Patients and methods : Seventeen patients underwent 2-level or 3-level corpectomy for malignant tumor (11 patients), infection (4 patients), or burst fracture (2 patients). Where possible, anterior approaches were selected.

  Results : Operative approaches included sternum splitting for T1-T2 lesions, extrapleural approaches for T4-L1 lesions, retroperitoneal approaches for L2-L4 lesions and posterolateral approaches for T3 lesions. Two-level corpectomy was performed in 12 patients and 3-level corpectomy in 7 patients. Cages (7 cases) and bone cement (5 cases) were used as the graft for spinal metastatic lesions, and autogeneous fibula grafts (4 cases) and ceramic spacers (1 case) were used for infected spinal lesions. Autogenous iliac bone (1 case) and ceramic spacer (1 case) were used for burst fractures. The bony endoplates were preserved and kyphotic deformities were corrected before and/or during surgery. For internal fixation, vertebral plates were used in 9 cases, pedicle screw and rod fixation systems where used in 4 cases, and a Luque rod was used in one case. All patients showed neurological improvement after their operations.

  Of the 17 patients, initial fixation was maintained in 14 and bone fusion was achieved in 10, although bone fusion was not estimated in 4 due to progression in malignantcy. Anterior support failure occurred in 4 patients during the follow-up period, due to graft subsidence. Artificial graft materials were used in all 4 of these failed operations, and in 2 of these cases, the lesions were in the upper thoracic spine.

  Conclusions : To achieve rigid spinal fixation, graft materials must be applied between intact vertebral endplates. In the upper thoracic spine, it is essential that the vertebrae be rigidly fixed.

  Objective : Posterior cervical fixation using pedicle screw technique and rod system is increasingly chosen a procedure for stabilization and reconstruction of the cervical spine ; however, it has inherent risks that are unique. We focused on the feasibility of posterior cervical fixation using pedicle screw technique, especially for cervical myelopathy associated with athetoid cerebral palsy, for rheumatoid arthritis, and for destructive spondyloarthropathy.

  Methods : Consecutive 22 patients with cervical spine instability associated with athetoid cerebral palsy, with rheumatoid arthritis, or with destructive arthropathy treated with posterior cervical fixation using pedicle screw technique were retrospectively reviewed. All surgeries were performed with the help of fluoroscopy and neuronavigation system.

  Results : In all cases, posterior fixation according to preoperative plan was accomplished, and the postoperative courses were good. No vascular or neurological complications such as nerve root problem occurred.

  Conclusion : Long-term follow-up evaluation is essential, particularly for patients with athetoid cerebral palsy, rheumatoid arthritis, or destructive arthropathy because the natural course of these disorders is very progressive and more destructive than that of usual cervical spondylosis.

  Objective : Spinal epidural hematoma (SEH) is an uncommon clinical entity. Herein, we have described our experiences with cervical SEH patients.

  Patients and methods : Clinical data were obtained for 8 patients (6 men and 2 women) with cervical SEH and were reviewed retrospectively. The average age of the patients was 66.6 years (range, 26-79 years). We evaluated the initial symptoms, history of anticoagulant therapy, pre-and posttreatment neurological function using the American Spinal Injury Association (ASIA) Impairment Scale and Neurosurgical Cervical Spine Score (NCSS), extent of hematoma and time interval from the initial ictus to the treatment.

  Results : Six patients experienced sudden-onset neck or upper back pain, and the other 2 patients experienced sudden motor weakness without pain as the initial attack. Four patients had received anticoagulation. One patient had received an analgesic, which may have contained acetylsalicylic acid, for 3 days before the attack, and one patient had coagulopathy due to an unknown cause. Six of the 8 patients presented with severe motor dysfunction or loss of motor function (ASIA grades A, B, and C). Neurological status in 6 patients improved by at least 1 grade after treatment. The hematoma extended to 2-5 vertebral segments, but there was no relationship between the extent of hematoma and severity of symptoms. All patients underwent surgical evacuation, and 4 of the 8 patients were treated within 8 h.

  Conclusion : During diagnosis in the early stages, it should be noted that the sudden onset of pain during the initial attack does not necessarily occur in all patients with cervical SEH. Our experience with cervical SEH shows that the severity of pretreatment neurological deficits is a reliable predictor of the outcome.

  Objective : To evaluate failed back surgery syndrome (FBSS) in patients with lumbar spinal canal stenosis and degenerative spondylolisthesis, who had undergone posterior decompression without fusion.

  Patients and Methods : We evaluated 112 consecutive patients (41 men and 71 women) who underwent posterior decompressive surgery without fusion between April 2001 and March 2010 in the neurosurgical department of Kushiro Rosai Hospital. The average age was 66 years (range, 36-85). The mean follow-up period was 46.3 months (range, 0-108). The definition of FBSS in this study is recurrence of symptoms after recovery of initial symptoms from initial surgery.

  Results : Among the 112 patients, 32 (28.6%) suffered from FBSS and 15 (13.4%) underwent re-surgery. In these 15 patients, the causes of FBSS were recurrence of lumbar canal stenosis (n=1), lumbar canal stenosis at upper adjacent level (n=7), lateral recess stenosis (n=1), foraminal stenosis (n=5) and far-out syndrome (n=1). The non-surgical causes of FBSS were sacroiliac joint dysfunction (n=21), piriformis syndrome (n=1), and arteriosclerosis obliterans (n=1).

  Conclusion : Accurate diagnosis of the etiology of symptoms is mandatory for appropriate treatment for FBSS. Our result indicated that foraminal stenosis is an important cause of re-surgery, although judgement of surgical indication is difficult. To prevent FBSS, it is important to have a knowledge of various associated diseases such as sacroiliac joint dysfunction.

  Object : We previously reported that patients with hereditary disorders of connective tissue (HDCT) or post-traumatic condition (PTC) may present with lower brain stem symptoms attributable to occipito-atlantoaxial (OAA) instability. We performed occipito-cervical fusion (OCF) using instrumentation for OAA instability. We examined the factors that influence the outcome and have reported the preliminary results.

  Materials and Methods : Osseous structures comprising the cranio-cervical junction were investigated morphometrically using a reconstructed 3D and 2D computed tomography (CT). We detected OAA joint instability in 445 patients with HDCT, PTC, degenerative diseases, cranio−cervical anomalies (CC anomaly), rheumatoid arthritis (RA), and tuberculosis. Surgical indication for OCF was determined on the basis of cranio-cervical traction test. OCF was performed in 250 patients using VERTEX MAX^TM or Synapse^TM reconstruction system, human fibula allografts, and INFUSE^® (rhBMP). We used navigations systems such as the Orbic 3D (intraoperative C-arm based CT system) and the Kolibri navigation system.

  Results : Out of 250 patients, 200 patients (80%) showed improvement or resolution of signs and symptoms ; condition of 40 patients (16%) remained unchanged and that of 10 patients (4%) deteriorated. Complete fusion was confirmed in 212 of 250 surgical cases (85%) using reconstructed 2D-CT and dynamic plain cervical X-ray examination. The problems encountered included instrument fracture, increasing instability at the next level after fixation, and incomplete fusion. The rates of improvement of clinical symptoms and complete bony fusion were significantly lower than those with HDCT, CC anomaly, and RA. The rate of development of novel lesions was significantly higher in patients in which fusion was performed at the C3level.

  Conclusions : OCF is effective for improving and stabilizing symptoms in patients with OAA joint instability. The cranio-cervical traction test was an important pre-operative procedure for selecting the surgical procedure. Complementary materials for bony fusion should be used in HDCT and RA patients. Although appropriate short segment fusion is necessary, several of our cases required long fusion. Considering the advantages and disadvantages of OAA joint fusion, the surgical indication should be selected carefully.

  Object : To study long-term outcomes of anterior decompression and fusion (ADF) and expansive laminoplasty (ELP).

  Materials and Methods : Our study included 120 patients who underwent iliac bone grafting via the modified trans-unco-discal approach (TUD) or ELP with spinous process or ceramic spacers over 5 years ; the neurological symptoms and Japanese Orthopedics Association (JOA) scores of these patients were reviewed.

  Results : Neurological symptoms and JOA scores improved in 111 out of the 120 patients (93%), and worsened in 9 patients (8%). There was no significant difference in the rate of improvement of neurological symptoms, and JOA scores in all groups. There was no significant difference in the improvement rates of neurological symptoms and JOA scores between all groups.

  Conclusions : ADF and ELP showed comparable rates of improvement in neurological symptoms and JOA scores. It is important to choose the appropriate methods according to the pathophysiological conditions. ADF should be performed only for the appropriate lesions, since the problems pertinent to the adjacent lesions may ensue.

  Purpose : To report technical points in posterior upper cervical fixation using C1 lateral mass screw.

  Materials and Methods : Thirty-seven consecutive cases of cervical spine instability underwent posterior cervical fixation with C1 lateral mass screw over the past 8 years ; there were 19 men and 18 women with a mean age of 66.1 years (range, 27-90). All cases received a comprehensive evaluation before surgery, including vascular assessment using computed tomography (CT) angiography. Preoperative radiological measurement and intraoperative dissection of the upper dorsal cervical field were performed. C1 lateral mass screw was inserted with the help of a navigation system and fluoroscopy. The posterior arch of the C1 was fixed using tape to avoid spinal-cord injury during C1 screw insertion. Clinical outcomes were determined according to the Japanese Orthopaedic Association scoring system and Frankel grading system. Most of these screws were inserted bicortically and connected with axial pedicle/laminar screws. Atlantoaxial midspace was grafted with iliac bone with polyester tape, by using a modified Gallie or McGraw method.

  Results : A total of 74 C1 lateral mass screws were placed, as planned, before surgery without any neural or vascular injury.

  Conclusion : Complications associated with C1 lateral mass screw fixation can be minimized by the careful image analysis before surgery and meticulous intraoperative exposure and cautious screw insertion. Although posterior fixation using C1 lateral mass screw is a useful procedure for stabilizing and reconstructing the upper cervical spine, surgeons should recognize the surgical indications, benefit, and possible risks.