Neuromyelitis optica (NMO) is an inflammatory neurologic disease characterized by severe optic neuritis and transverse myelitis. Other features of NMO include female preponderance, higher onset age, severe functional disability, longitudinally extended spinal cord lesions (>3 vertebral segments), and absence of oligoclonal IgG bands. The relation between NMO and multiple sclerosis (MS) has been discussed for a long time, but since the discovery of aquaporin 4 (AQP4) antibody, an NMO-specific autoantibody, clinical, MRI, and laboratory features that distinguish NMO from MS have been established. This autoantibody binds to the extracellular domain of AQP4, which is highly expressed in foot process of astrocyte. Recent neuropathological studies strongly suggest that NMO is an AQP4 antibody-mediated astrocytopathy. High-dose intravenous methylprednisolone is the first-line therapy for acute exacerbations of NMO. But plasma exchange should be started as soon as possible when corticosteroid is not effective. If untreated, AQP4 antibody-positive patients are highly likely to experience relapses within a year. Thus, immunosuppressive therapy should be initiated without delay. Unlike in the ease of MS for which interferon-beta is the first-line treatment, corticosteroid and immunosuppressants are administered to prevent relapse in NMO. Taken together, AQP4 antibody has diagnostic, therapeutic and pathogenetic implications in NMO.

  Ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine cause myelopathy with anterior spinal cord compression, the cause is usually progressive and refractory to conservative treatment. Therefore, early decompressive surgery is imperative in such cases. However, decompression surgery of thoracic OPLL is difficult, and its outcome is often poor. We investigated whether anterior decompression and bony fusion via the anterior approach can be used for the treatment of myelopathy secondary to thoracic OPLL. The outcome and complications associated with this method were analyzed in 9 patients who were treated with this procedure. Of the 9 patients, 3 were treated using transsternal approach, and 6 were treated using transthoracic approach. Mean blood loss was 291.6 mL for the transsternal approach and 379.1 mL for the transthoracic approach. The Japanese Orthopaedic Association score (JOA score) was used to evaluate the severity of myelopathy (possible highest score, 11 points). The recovery rate of JOA score was used to evaluate the surgical outcome. The mean preoperative JOA score was 4.7, and it improved to an average of 7.8 at the final evaluation. The average recovery rate of the JOA score was 52.2%. The clinical symptoms and JOA score improved compared to the preoperative conditions in 8 patients but remained unchanged in 1 patient. Surgical complications included dural tear in 2 patients and intercostal neuralgia in 1 patient. One patient had to be transferred to a rehabilitation facility. In the other 8 patients, the mean hospitalization was 15.4 days. Anterior decompression and fusion is an effective surgical procedure for the treatment of thoracic OPLL and yields good and stable long-term results. An anterior procedure that results in adequate decompression of the spinal cord and affords good spinal stability is recommended for anterior lesions such as OPLL, which compress the anterior spinal cord at the thoracic spine.

  Study Design : Observational study with retrospective computerized tomography (CT) analysis and clinical study.

  Objective : The purpose of this study was to examine the microanatomy of the lamina-facet junction and define the optimal position of the lateral gutter in cervical laminoplasty.

  Materials and Methods : Sixty patients who underwent cervical laminoplasty were retrospectively studied using CT images. To examine the anatomical features of the lamina-facet junction, the distance between pedicles, frequency of the presence of valley of lamina (VOL), and the distance between VOL were measured. In addition, to investigate the relationship between damage to the lamina and position of the lateral gutter, we set up the inner surface of pedicles with a medial pedicular line (MPL), and then measured the distance from the MPL to the lateral gutter and the frequency of damage to the inner cortex.

  Result : The distance between pedicles was maximal in C5. High frequencies of VOL were found in C4, 5, 6, and 7. However, differences between the width of pedicles and VOL were larger in the lower cervical spine, indicating that in the lower cervical spine, VOL might not be suitable as a surgical landmark for making the lateral gutter. It was revealed that the displacement of the lateral gutter toward the medial side increased the risk of damage to the inner cortex.

  Conclusion : Inadequate position of the lateral gutter causes insufficient decompression of the spinal canal in cervical laminoplasty. In this study, we revealed that the optimal position of the lateral gutter is on the MPL.

  Objective : Concerns for instability following decompression for lumbar stenosis have led to development of procedures with minimal destruction of the elements of the spine and muscles. Fenestration, consisting of partial laminotomy and medial facetectomy, achieved lower incidence of postoperative instability compared to laminectomy. We had performed fenestration for patients with neurogenic claudication until 2005 when we developed a new procedure, myoarchitectonic spinolaminoplasty (MSLP), to preserve all musculoskeletal interactions including that of multifidus. In this study, clinical and radiological outcome of patients who underwent fenestration or MSLP were retrospectively compared.

  Methods : In fenestration group, the spinous process (SP) and laminae were exposed by subperiosteal detachment of the muscles. Bilateral laminotomy and medial facetectomy were performed. In MSLP group, the interspinous ligament and caudal half of the SP were vertically split without detaching the multifidus, cut-separated at its junction with the lamina while leaving connection with the cephalad part of the SP. The split SP was retracted laterally, creating a quadrilateral window. Partial laminectomy, removal of ligamentum flavum, and undermining of superior facets were performed. Preoperative and follow-up clinical and radiological assessment included Japanese Orthopaedic Association (JOA) score for low back pain, lordotic angles, % translation and disc angles.

  Results : Fenestration group comprised 7 patients, mean age 71.2 years, with mean follow up of 3.5 years. MSLP group included 14 patients, mean age 66.8 years with mean follow up of 2.3 years. No patient had reoperation for symptomatic lumbar instability. Preoperative JOA score regarding back pain was 1.4 in fenestration and 1.6 in MSLP groups, and postoperatively it was 2.0 in fenestration and 2.8 in MSLP groups (p=0.006). Preoperative JOA scores for leg pain and gait were 1.6 and 0.6 in fenestration group and 1.2 and 0.7 in MSLP group, and those postoperatively were 2.4 and 2.7 in fenestration and 2.6 and 3.0 in MSLP groups. Preoperative and postoperative lumbar lordosis (mean) was-18.5 and-18.4 degrees in fenestration and-15.7 and-16.0 degrees in MSLP groups. Preoperative and postoperative % slip was 6.1% and 7.1% in fenestration and 2.8% and 5.0% in MSLP groups. Preoperative and postoperative disc angle was-7.7 and-9.1 degrees in fenestration and-7.7 and-6.3 degrees in MSLP groups.

  Conclusions : Clinical and radiological lumbar instability was rare after fenestration and MSLP. Back pain was less in the MSLP group.

  Lumbar degenerative spondylolisthesis (LDS) is a common disease that results in lumbar stenosis. However, a recommendations for treatment, or standardized surgical treatment has not yet been established. LDS treatment involves release of the stenosis, or decompression followed by fixation and fusion. The main decision of procedure selection depends on the presence of lumbar instability, which is mostly associated with lumbar discomfort. However, the choice of the adequate procedure can be diversified when lumbar discomfort is not related to lumbar instability.

  We examined 51 cases of LDS between August 2006 and Jaly 2009. Decompression alone or a combined fixation/-fusion procedure was selected according to the absence or presence of lumbar discomfort, respectively. Lumbar discomfort was observed in 73.7% of the cases with spinal instability, and lumbar instability was strongly correlated with lumbar discomfort. Decompression procedure was more minimally invasive, and fixation/-fusion one became less invasive. Both decompression and fixation/-fusion groups showed equally improved neurological status, and discomfort, including low back pain, minimized. Neither procedures caused any permanent disability. Two patients (5.8%) in the decompression group showed symptoms that had originated because of worsening of spinal instability. Subsequently, the patients were treated with transforaminal lumbar interbody fusion (TLIF), and good recovery was achieved.

  In most cases of LDS without lumbar discomforts, LDS can be adequately treated with minimally-invasive decompression alone. However, fixation/-fusion is required in cases of LDS with lumbar discomforts, and in rare cases, fixation/fusion may be subsequently required in cases without lumbar discomfort.

  Lumbar radiculopathy caused by lesions outside the spinal canal, such as far lateral lumbar disc herniation (FLLDH) and lumbar foraminal stenosis (LFS), are not rare conditions. Over the past 6 years, we have treated 5 patients with FLLDH and 8 with LFS. Last year, the incidence of FLLDH and LFS among patients undergoing lumbar surgery patients was approximately 10%. A lateral intermuscular approach was selected as the operative method of choice for all patients with FLLDH and 4 patients with LFS who had no lesions inside the spinal canal. In 2 patients with LFS who had concurrent medial lumbar canal stenosis (MLCS), a paramedian combined approach and decompression of both MLCS and LFS was performed. In 2 patients who had a medical history of laminectomy for MLCS, facetectomy and posterior lumbar interbody fusion (PLIF) with a pedicle screw was performed. In all patients, symptoms completely resolved postoperatively and the post-operative course was uneventful. In conclusion, we would like to stress that accurate diagnosis and adequate surgical treatment will ensure favorable results for patients with FLLDH and LFS.

  We report our experiences of using multiplanar reconstruction(MPR)and 3-D CT scans in combination with a 3-D viewer, AquariusNET(TeraRecon eCo.), in spinal surgery of 44 patients from December 2010, and we evaluated the usefulness of this combined approach.

  The anatomical architecture of the neck could be clearly visualized using this system. Further, in cervical spine surgery performed via the anterior approach, the side of approach, location of skin incision, trajectory of approach, and the site and width of corpectomy through which the lesion was to be approached could be determined easily.

  This viewer is also useful in screw-insertion procedures such as those involving a laminar screw, lateral mass screw insertion in the cervical spine, and pedicle screw fixation in the lumbar spine. In MPR and 3-D images, a simulating entry point is created on the surface of a 3-D image and a screw-insertion trajectory is chosen. The length and direction of the screw are measured. This system is simple and easy and can be used on a personal computer.

  Objective : After anterior cervical decompression and fusion (ACDF), post-operative subsidence of the vertebral body or migration of interbody cages may lead to mala-lignment and inadequate surgical results. We measured and evaluated post-operative changes in the height of the intervertebral space after ACDF using a cylindrical titanium interbody cage.

  Methods : Twenty-eight patients (21 men and 7 women) at a mean age of 52.5 years underwent ACDF using a cylindrical titanium interbody cage between March 2003 and April 2010. Among these, 21 patients had a single-level fusion and 7 had a double-level fusion. Pre-operative and periodic post-operative lateral radiographs were obtained to measure the decrease in total vertebral height of the fused vertebral bodies at the center and the anterior and posterior margins. Post-operative and pre-operative heights were compared, and the difference was expressed as a percentage. The decrease in vertebral height at the final follow-up was compared between the single-and double-level fusions, single-and double-cage fusions, and large-and small-cage fusions. The type of collapse of the inter-vertebral space was classified as anterior collapse, total collapse, and posterior collapse, and the frequency and extent of the collapses were compared.

  Results : Compared to the pre-operative vertebral heights, the average final vertebral heights decreased to 95.3% at the anterior margin, 95.6% in the center, and 97.0% at the posterior margin. The decrease at the anterior margin was significantly greater than that at the posterior margin. Further, the decrease at the anterior margin was more significant in double-level (93.0%), single-cage (94.3%), and large-cage fusions (94.8%) than single-level (96.1%), double-cage (97.1%), and small-cage fusions (97.2%), respectively. Anterior collapse (60.0%, 17/25) was greater than total collapse (28.0%, 7/25) and posterior collapse (12.0%, 3/25).

  Conclusions : Post-operative decreases in the height of the inter-vertebral space after ACDF using a cylindrical titanium interbody cage were more significant at the anterior margin than at the center or posterior margin. Furthermore, the decrease seems to be more marked in patients undergoing double-level fusions than in those undergoing single-level fusions.

  A spine exposed to radiation can easily become compromised with of osteonecrosis and fracture due to hematogenous disorder and bone fragility. We report cases of 2 patients with pyogenic spondylodiscitis caused by mixed bacterial infection after radiation therapy and review the literature. The patients were a 67-year-old woman (case 1) who had undergone catheterization for acute myocardial infarction 7 years before the time of presentation and a 76-year-old man (case 2) who had undergone radiotherapy for pharyngeal cancer 4 years before the time of presentation. Patient 1 presented with fever, lumbago, and severe pain in the right lower limb. Patient 2 presented with fever and quadriplegia. Patients 1 and 2 were diagnosed with pyogenic spondylodiscitis at L3/4 and C5/6, respectively. Computed tomography-guided puncture was performed in case 1, and decompression and fusion were performed via an anterior approach in case 2. The culture test revealed mixed bacterial infection in both cases. The infection was treated by using antibiotics and by administering hyperbaric oxygen therapy.

  A 71-year-old man had been treated with hemodialysis for 34 years. The patient complained of painful dysesthesia in the right lower extremity, and 7 years ago underwent decompressive right partial laminectomy at the L4/L5 level. Painful dysesthesia in the bilateral lower extremities occurred four years ago, following a fracture in the right inferior articular process of the 4^th vertebral body. Consequently, decompressive left partial laminectomy at the L4/L5 level was performed. The painful dysesthesia relapsed in the right lower extremity following a fracture in the left inferior articular process of the 4^th vertebral body, and he was treated with posterior lumbar interbody fusion (PLIF) 3 years ago. The painful dysesthesia in the bilateral lower extremities, lumbago, and intermittent claudication recurred, and an X-ray showed instability between the L4 and L5 levels. Computed tomography at the L4/L5 level showed that both the spacer and iliac bone graft were protruding into the spinal canal. Magnetic resonance imaging revealed spondylolisthesis and compression of the dural sac at the L4/L5 level.

  Transforaminal lumbar interbody fusion (TLIF) was performed at the L4/L5 level using a boomerang-type intervertebral spacer. The symptoms improved markedly after the operation. Percentage slip (the percentage of vertebral slippage) and angle of slippage improved after TLIF with the recovery of segmental sagittal lordosis. No protrusion of the spacer has occurred 10 months after the surgery. TLIF is a viable option for salvage surgery after a failed PLIF operation.

  Microscopic bilateral spinal decompression via unilateral laminotomy (MBDUL) is one of the less-invasive surgeries for lumbar canal stenosis (LCS). Although this surgical technique is now familiar to many spinal surgeons, some difficulties are encountered in preserving the facet joint in the side in which laminotomy is performed and in achieving adequate decompression in the contra-lateral side. In this report, we describe some anatomical landmarks that are helpful for achieving these surgical goals. Before bone cutting, we roughly determined the extent to which laminotomy could be performed on the basis of the following landmarks ; (1) the notch in the upper lamina, (2) the caudal end of the inferior articular process, and (3) the lateral edge of the pars interarticularis. When performing medial facetectomy, we observe the capsular portion of the yellow ligament and the medial edge of the pedicles of the lower vertebra. These landmarks help determine the necessary and adequate extents to which facetectomy and ligamentectomy should be performed. This knowledge can help preserve the facet joint even during surgical decompression of the upper lumbar spine. In the 19 cases examined in the study, the mean duration of post-operative hospital stay was 13.2 days (range, 4-30 days), and the mean period for the patients to return to their previous work was 24.0 days (range, 4-60 days). None of the patients developed spinal instability during the follow-up (mean follow-up period, 39.2 months). Japanese Orthopedic Association scores and visual analogue scale scores for pain and numbness improved after the operation, and the scores were maintained at the final follow-up performed after more than a year. These findings suggest that adequate neural decompression was achieved with MBDUL. In conclusion, the anatomical landmarks described above are useful for constantly achieving good surgical outcomes with MBDUL.

  In tarsal tunnel syndrome, vascular compression beneath the flexor retinaculum has been suggested as one of the causes of nerve insult. We have attempted reconstruction of the tunnel after transposition of the vasculature from the tunnel. However, among 205 lesions with tarsal tunnel syndrome surgically treated using such a reconstruction method, we experienced 6 recurrences. Adhesion and compression by granulation in the reconstructed tarsal tunnel was a common finding. To avoid this, we designed a new method. After the flexor retinaculum is incised slightly to the medial side of the tunnel, the posterior tibial artery and the medial and lateral plantar veins (vascular complex) are detached from the medial and lateral plantar nerve. The vascular complex is then relocated from the tunnel and wrapped with the flexor retinaculum laterally outside the tunnel. This method may be more effective than preexisting ones. Long term efficacy of our method is to be proved in accumulation of experiences.