To evaluate the outcome of bilateral decompression through a unilateral approach for three level involvements in terms of clinical results and lumbar alignment, and also to compare the results with those of conventional fenestration.

The investigation group contained 22 patients with 74.1 years in average. The control group contained 15 patients with 70.8 years in average. Operation time, blood loss, and JOA score were evaluated. Lumbar Cobb angle, lordosis angle, and ROM were measured with radiographs pre- and post operatively. Then the results of the two groups were compared respectively.

Average operation time was 151 min, blood loss was 315ml, and recovery rate in JOA score was 38.7% in the investigation group. There was a tendency that average operation time was shorter in the investigation group. There was no significant difference in lumbar alignment and ROM in the two groups, except a greater postoperative lordosis angle in extension in the investigation group. No spondylolisthesis has developed in the investigation group.

The clinical outcome of the investigation group seems to be equal to that of the fenestration group. It was suggested that postoperative lumbar instability rarely develops, since hypertrophic spondylosis is advanced in LSS with multilevel involvements if the spinus processes are preserved.

Lumbar degenerative spondylolisthesis (LDS) is a common disease resultingin lumbar stenosis. However, in spite of some recommendations, standardized surgical treatment has not yet been established. The question is if we simply release the stenosis, or should add fixation and fusion to decompression. The main decision in procedure selection depends on the presence of lumbar instability, which is mostly associated with lumbar discomfort. However, the choice of adequate procedure can be diversified when lumbar discomfort is not related to the instability.

For forty-eight cases of LDS during the last three years, we selected the decompression alone or combined fixation / usion procedure accordingto the absence or presence of lumbar discomfort respectively. The decompression procedure was much less invasive, and fixation / fusion also became less invasive. Both the decompression and fixation/fusion groups improved in neurological status, and the discomfort includinglow back pain also improved to minimal symptoms. Two cases (5.9%)of the decompression group showed symptoms originating from instability progression. They were subsequently applied TLIF(transforaminal lumbar interbody fusion), and brought to good recovery.

Most cases of LDS without lumbar discomfort can be adequately treated by minimally invasive decompression alone. However, the fixation/fusion procedure should be used for LDS with lumbar discomfort, and in rare cases, can be need subsequently for LDS without discomfort.

[Purpose] To investigate the clinical results of microendoscopic decompressive(MED)surgery for elderly lumbar stenosis patients.
[Materials and methods] 61 patients more than 75 years(Elderly group)and 96 patients less than 65years(Control group)underwent MED surgery with minimum 2 years follow-up. Clinical results were evaluated with the JOA score. Blood loss, hospital stay, physical status of ASA and number of co-morbid diseases were investigated.

[Results] Pre and postoperative JOA score and recovery rate in group E were 14.0, 22.6, and 57.1%, and on the other hand, in group C, 15.0, 25.0, and 72.2%. Blood loss was 22.3 ml in group E and 28.4 in group C. Hospital stay was 12.4 in group E and 8.8 in group C. Physical status of ASA in group E included 3 class I , 50 class II , and 8 class III and in group C included 37 class I , 56 class II and 3 class III . The number of co-morbid diseaseswas 1.8 in group E and 1.0 in group C.

[Discussion and conclusion] MED surgery had no serious effect on the intraoperative cardiopulmonary system because of the small blood loss. MED surgery was a useful option for these elderly patients.

We studied 39 cases of spinal surgeryover 80 years old from 1976 to 2009. After 1992, the operative cases of spinal surgeryover 80 years old occupied 3.0~3.4 percent of all spinal operations. The rate became larger than 0.7% from 1976 to 1991.

Cervical spinal operations were done in 31 cases. In 16 cases, cervical osteoplastic laminoplasties were done, and in 12 cases, anterior cervical discectomies. Preoperative JOA scores were 3.14 in average, and postoperative scores were 7.76. The recoveryrate was 28%. In spite of this poor recoveryrate compared to that of younger cases, mild regain of ADL was veryuseful in elderly persons. In about 50% of cases, postoperative elderlypersons could return to their previous life. During the postoperative period, transient delirium was seen in 51%.

Among 8 cases of thoracolumbar lesions, one case of progressive L1 compression fracture had to be reoperated for loosening of pedicle screw fixation due to osteoporosis.

[Objective] The objective of this study is to report the clinical outcome of two surgical methods of multilevel anterior corpectomy and arthrodesis for CSM or OPLL in elderly patients over 70 y/o.

[Materials and methods] Six CSM cases and 16 OPLL cases, treated with anterior multilevel ACF immobilized by Halo-vest between 1997 and 2006, as well as 4 CSM and 2 OPLL cases, treated since 2007 with hybrid decompression and arthrodesis with anterior dynamic plate, were involved in this study. OR time, blood loss, length of hospital. Stay after surgery, hardware failure, perioperative complications, union rate and JOA score before and at F/U time were investigated in each group. The Mann-Whiteny U test was used for statistical analysis.

[Results and conclusion] All cases improved significantly after multilevel ACF;however, hybrid methods with a dynamic plate could decrease OR time, blood loss and length of hospital stay significantly and eliminated the halo-vest immobilization without hardware failure.

We concluded that the anterior hybrid method is a viable option for CSM and OPLL with multilevel dysfunction of the spinal cord even in elderly patients.

[Purpose] This study describes resection of a spinal cord tumor with a Muscle-Preserving Interlaminar Decompression(MILD)approach.

[Surgical procedure] Midline incision was made and the supraspinous ligament was split longitudinally. After exposure of the dorsal aspect of the spinous processes,the spinous process was drilled from the cancellous portion toward the cortical portion without detaching the paravertebral muscles. After dividing the complex of the spinous process periosteum,the fascia of paravertebral
muscles,and the supra- and interspinous ligaments,further bone drilling was performed till the ligamentum flavum appeared. After flavectomy,routine removal of the tumor was performed.

[Material and Methods] Six patients with spinal cord tumor were prospectively investigated. Operation time,approach time,intraoperative blood loss,recovery rate of JOA score,complication, and alignment were evaluated.

[Results] The mean operation time was 147 minutes,and the mean approach time was 36 minutes. The mean intraoperative blood loss was 29g,and the mean recovery rate of JOA score were 53.8% (thoracic vertebrae)and 48.5%(lumbar vertebrae).

[Discussion] The clinical outcome of this procedure was satisfactory. A bloodless,symmetrical, wide,and variable operative field is secured by preserving the complex of the spinous process periosteum,the fascia of paravertebral muscles,and the supra- and interspinous ligaments.

Seventy-one cases with 75 lumbar interbody fusion operations are reported. These operations were performed under a micro-endoscopic method, completely using the SEXTANT^®system (Medtronic Sofamor Danek)with newly designed guide-wire tubes. The series consists of 67 level fusions of PLIF and 8 levels of TLIF. The mean operation time was 148 minutes(78~259)for one level fusion and 161 minutes(78~386)overall. Average intra-operative bloodloss was 136ml (20~515)andtransfusion was only neededin 2 early cases.

The SEXTANT^®system is a sophisticatedone, which has to be usedproperly andis somewhat technically demanding.

Our guide-wire tube seems to be useful for reducing the frequent use of a C-arm imageintensifier.

Microendoscopic spinal surgery has become increasingly popular.

Indications have expanded to include cervical radiculopathy and lumbosacral extraforaminal stenosis. Bleeding is usually well controlled in regular microendoscopic surgery, including lumbar discectomy or decompression for lumbar canal stenosis. However, cervical foraminotomy and lumbosacral extraforaminal fenestration have been known to cause difficulty due to active bleeding. Arista^®(microporous polysaccharide microspheres)is a newly approved hemostatic powder made from purified plant starch. On contacti with bleeding, the material absorbs water and low molecular weight compounds from the blood, concentratingplatelets and clottingproteins at the bead surface. It is free from virus or prion and non-immunogenic. The powder is readily absorbed in tissues in 24 to 48 hours. It has been used in more than 250,000 cases, mainly in general surgery. We used Arista^® in five cases of these difficult microendoscopic procedures. The powder material was applied topically and soft pressure was held for one minute. Active bleedingwas brought under control in all cases. Arista^®can be applied safely and effectively in microendoscopic spinal surgery.

[Objective] The purpose of this study was to evaluate the clinical and radiographic outcomes of one-leveled instrumented minimally invasive transforaminal lumbar interbody fusion(TLIF), which permits the surgeon to reduce degenerative lumbar spondylolisthesis percutaneously.

[Methods] A retrospective analysis was performed on 28 patients(mean age;66.1 years)who underwent reduction-TLIF, which reduced spondylolisthesis percutaneously, using translational screw extenders(Medtronic Sofamor Danek, Co., Ltd.)between June 2007 and April 2008. As a control group, we examined 28 patients(mean age;66.8 years)who underwent the regular-TLIF, using the regular SEXTANT system (Medtronic Sofamor Danek, Co., Ltd.). The following parameters were compared between the two groups;clinical and radiological outcomes, operation time, estimated blood loss, and length of hospital stay.

[Results] There was no significant difference in surgical time, blood loss, length of hospital stay, or clinical results between the two groups one year after the operation. As for%slip one year after the operation, the reduction-TLIF group was found to show a significant improvement in comparison with the regular-TLIF group.

[Conclusions] The reduction-TLIF using translational screw extenders for degenerative lumbar spondylolisthesis provided a better radiological outcome than regular-TLIF for the reduction of lumbar spondylolisthesis.

We macro-totally excised dumbbell-shaped cervical spinal cord tumor by a new surgical procedure, in which unilateral posterior arches were pivoted not on the lateral gutters of the laminae buton the divided pedicles.

Through antero-lateral approach, the outer wall of the foramen transversarium of the affected vertebrae was removed to dislodge the vertebral artery, followed by excision of the anterior tumor component. The antero-lateral procedure was finished by dividing each inner wall, the pedicle, to make a pivot on which the unilateral arches rotated. Through midline posterior approach, unilateral
arches were expanded on the pivot of the pedicles after longitudinally splitting the spinous processes with their attached muscles undisturbed bilaterally, then the posterior tumor component was removed.

Advantages of the procedure are as followed;

1. the anterior tumor component is securely excised with the vertebral artery in control,

2. the intracanalicular space is more widely exposed by pivoting on the pedicle rather than lateral laminar gutter,

3. the posterior musculature is kept undisturbed as laminar gutter is unnecessary,

4. the unilateral arches are easily and completely reduced due to the undamaged intervertebral joints guiding the reduction,

5.safe and less invasive revision surgeries can be performed on recurrentt umors.

Anterolateral partial vertebrectomy(ALV)of the cervical spine which involves drilling into the anterolateral part of the vertebral bodies enables radical resection of the lesion, without anyfusion. The authors describe a surgical technique of ALV for ossification of the longitudinal ligament of the cervical spine (OPLL). There are several tips in this procedure. The vertebral bodies can be approached more laterally, so that the anterior edge of the vertebral bodies and the anterior longitudinal ligament are not injured, preserving more than half of the vertebral bodies. In drilling of OPLL, we tryto preserve the thin OPLL to maintain the bonycontinuityuntil the last step of decompression, to prevent the flotation of the OPLL, which mayresult in spinal cord injury. Because the bulging of the decompressed dura mayobstruct the passage, the contralateral edge of OPLL must be resected first.

Bystrictlyobserving these points, anythick OPLL can be resected radicallyand safely, without anyfusion.

[Purpose] Axial pain and loss of cervical curvature are common complications after cervical laminoplasty. To reduce those problems, we developed a novel laminectomy technique. After a unilateral spinous process-splittingapproach, hemi-laminectomy on the one side and under-cutting laminectomy on the contralateral side were done. The purpose of the study is to report the clinical
and radiological results.

[Material and Methods] Twenty five consecutive patients (M/F=18/7) who underwent this procedure were prospectively followed. Etiologies were CSM (n=14), OPLL (n=9), disc herniation with developmental stenosis (n=1), and spinal cord injury without radiographic abnormality(n=1). Duringsurg ery, the spinous process was split in the midline and divided at its base on one side. Hemi-laminectomy was done on the exposed side. Retracingdeep extensor muscles in the interlaminar portion on the contra-lateral side, the superior half of the lamina was resected. After the basal portion of the spinous processes was resected, undercuttinglaminectomy in the remainingportion on the contra-lateral side was performed.

[Results] The average recovery rate was 53.5%. Average VAS score was 0.4 at the final follow-up. Mean C2-7 angle was 10.8°preoperatively, and 9.9°at the final follow-up.

[Conclusion] This procedure indicates multi-levels compressive myelopathy such as OPLL and developmental stenosis.

[Purpose] To report our experience of transcorpal anterior foraminotomy for radiculopathy due to cervical spondylosis or disc herniation, under careful consideration of indication.

[Material and Method] In the past 2 years (2007/7-2009/6), 13 patients underwent anterior foraminotomy in our institution. There were 12 men and one woman, whose ages ranged from 39 to 71 years(mean 55.2 years). The operative indication was uncontrollable radiculopathy caused by herniated disc or osteophyte. Under general anesthesia, anterior decompression was performed. A small vertebrotomy 6 to 8 mm in diameter was made at the inferolateral corner of the vertebral body, and microscopic root decompression was performed through this hole with special attention to preservation of the Luschka joint and intervertebral disc.

[Result] Root pain was relieved in all the cases. No complication was found including neurovascular damage.

[Conclusion] Although the follow-up period has been short and the number of patients has been small, this procedure seems to be useful. Operative indications could be extended for patient s with malalignment or canal stenosis. To avoid postoperative scoliosis, The Luschka joint have to be preserved. Maneuvers for hemostasis would be difficult, so careful operative manipulation is required.

To minimize damage to the deep extensor muscles, we have developed a procedure for exposing the posterior cervical spine. We describe the results of a muscle-preserving posterior foraminotomy, with a new approach to the posterior foraminotomy which preserves all muscular attachments to the spinous processes.

Between April 2003 and March 2009, 30 patients with cervical spondylotic radiculopathy or cervical disc herniation underwent the foraminotomy.

The mean follow-up period was 39 months(range 5-62). Mean operation time was 125min(range 58-195). Mean blood loss during operation was 51g(range 0-560).

Improvement of radicular pain was noted in each patient. Postoperative persistent axial pain was not noted in any patient.

The key to success in this newly modified approach is to divide the deep cervical fascia to unveil the underlying deep extensor musculature. The laminae and intervertebral joint are exposed by bluntly spreading the free space(ISS triangle)between the interspinalis and the adjacent upper and lower semispinalis cervicis muscles with a small nerve dissector. This new exposure can be used in a variety of posterior cervical spine operations such as lateral mass screwing and fenestration for cervical calcification of the yellow ligament.

[Objectives] Various adverse events or surgical complications of anterior cervical discectomyand fusion(ACDF)have been reported. The purpose of this studyis to describe rare and unpredicted complications of ACDF.

[Method] We reviewed 680 patients with cervical spondylosis, disc herniation and ossification of posterior longitudinal ligament who underwent ACDF. Two cases with rare postoperative complications were selected to be reported as sentinel events.

[Result] 1) A 36-year-old obese man with ossification of the posterior longitudinal ligament who presented with progressive myelopathy underwent ACDF. The patient weighed 160kg and had a short neck. When a surgical microscope was introduced after dissecting and retracting soft tissue, we happened to find a tear of the pharyngeal mucosa. 2) A 48-year-old man with cervical spondylotic myelopathy underwent ACDF. The head was fixed with a three-pin head clamp. When the surgery was completed, we found anisocoria and suspected head-pin-induced intracranial hemorrhage. However, it was Hornerʼs syndrome caused byintraoperative injuryof the cervical sympathetic trunk.

[Conclusion] The operative complications include the predictable and avoidable, and also the unpredictable and unavoidable. All preventive measures fail to work in some cases. When a rare operative complication that was not mentioned in the preoperative informed consent form occurs, we intend to disclose the incident sincerelyto the patient and familyand apologize with empathy.

[Introduction] The O-arm is a new intraoperative 3D imaging device that allows navigated pedicle screw(PS)placement within a few seconds after scanning the vertebrae. This study was conducted to test the hypothesis that the O-arm with or without a navigation system is highly accurate.

[Methods] A total of 152 PSs were placed in 26 patients (average age 62.5 years). Att he surgery for the lumbar spine, the positions of pedicle screws were checked with 2D/3D image in the O-arm just after PS placement. At the surgery for the cervical and thoracic spine, navigation based on intraoperative 3D images with the O-arm was used during PS placement. Positions of all pedicle screws were evaluated on the CT scans after surgery.

[Results] All of 99 PSs inserted in the thoracic and lumbar spine were positioned within the pedicles on CT scans after surgery. Of 53 cervical PSs, 4 screws (7.5%) was classified as Grade 1(PS breaking the pedicle wall but with>50% of screw diameter remaining within the pedicle), and 1 screw (1.9%) were classified as Grade 2(PS breaching the pedicle wall and with>50% of screw diameter located outside the pedicle).

[Conclusions] PS placement with the new O-arm is highly accurate and reliable.

[Purpose] To evaluate the incidence of complications for ACDF, and to clarify the matters that should be considered for the procedure.

[Patients and Methods] The retrospective study includes 15 patients with compressive myelopathy and radiculo-myelopathy due to degenerative disc prolapse or osteophyte formation. All patients underwent ACDF with Syncage-C packed with autologous iliac cancellous bone. Radiographic data of the patients were collected and analyzed. JOA score was used for evaluation of the patientsʼ
neurological states. Complications of the procedure were collected and resolution of the complications was discussed.

[Results] The average age of patients was 49.3 years and the average follow up was 19.6 months. JOA score improved from 12.8 to 14.7 points with 60.8% improving rate. The patients obtained 1° local angle, and 3.9°cervical lordosis, and lost 5.8°ROM after the surgery. There were 6 cases of cage subsidence and one case of paralysis.

[Discussion] Appropriate implant selection and placement appear to be the key factors preventing cage subsidence. Mechanical support of the implant by anterior cortical bone of the vertebral body and maximal cage to end-plate surface ratio seem to be crucial. The procedure should be abvoided for patients with severe spondylosis accompanied by osteoporosis.

[Objective] Although advancement of interventional radiology(IVR)may achieve the endovascular obliteration of spinal vascular lesions, surgical obliteration may be safer and more efficacious in some cases. The authors focus on the surgical safety and radical cure in cases of spinal arteriovenous lesions.

[Methods] Twenty cases of spinal AVM or AVF treated over the past 10 years were analyzed retrospectively. Two cases were classified as extradural AVF, 13 as dural type, 3 as intramedullary AVM, and 2 as perimedullary type. All of the operations were performed using intraoperative DSA or neuromonitoring.

[Results] Sixteen of 20 patients underwent the surgical treatment as an initial treatment, and the remaining 4 as a salvage treatment after IVR. Safe and radical cure was achieved in all cases except 2 of intramedullary AVM. Functional assessment 3 months after surgery demonstrated acceptable improvement or stabilization of ADL. There was no case of recurrence during the follow-up period.

[Conclusion] Management of spinal arteriovenous lesions needs the team effort including the advanced skills and knowledge of neuroradiology and intraoperative support. Accurate and early diagnosis is mandatory to avoid permanent neurological deficit.

[Object] Because spinal intradural cavernomas frequently cause bleeding,they should be treated appropriately. In this study,surgical outcomes of spinal intradural cavernomas were studied to elucidate the appropriate treatment.

[Patients and Methods] During the period from 2000 to 2009, 14 patients with a spinal intradural cavernoma(12 females and 2 males ranging from 13 to 66 years of age)were treated surgically. The angiomas arose from the cervical cord in 7 patients,the thoracic cord in 5,the conus medullaris in one,and the cauda equina in one. Five patients suffered from severe motor dysfunction and could not walk due to hematomyelia. The remaining 9 patients complained of mild neurological deficits.

[Results] The posterior approach was employed and total resection of the tumor was accomplished in all patients. The angiomas were resected meticulously from surrounding gliotic tissues.
Neurological symptoms improved in 7 patients,were unchanged in 6,and worsened temporarily in one patient after surgery.

[Discussion and Conclusion] Total resection of spinal intradural cavernomas should be attempted because the residual angioma may cause hematomyelia and severe neurological deficits,and they can be removed without neurological sequelae if less-invasive manipulations are conducted.

[Objective] As basic management of spinal cord tumors arising from or around the conus mudullaris, both sphincter and lower extremityfunction should be carefullyexamined. The authors focus on clinical course and functional recoveryafter surgeryin such cases.

[Methods] Seventeen cases were found during the past 6 years. Two patients presented with acute onset, and the remaining 15 presented with gradual onset. All cases received a comprehensive assessment of gait, sensation and urination before and 3 months after surgery.

[Results] Two cases of acute onset were myxopapillary ependymoma and schwannoma respectively, and were accompanied byurinaryretention resulting from intratumoral hemorrhage. Fifteen cases of gradual onset were classified as schwannoma in 11 cases and ependymoma in 2, subpial lipoma in 1 and epidermoid cyst in 1. Microscopicallytotal removal of the tumor was accomplished in 15 of 17 cases. Functional assessment demonstrated a significant improvement after surgeryin all cases.

[Conclusion] Acute onset resulting from intratumoral hemorrhage was rare but need to be considered. Careful inspection of the interface between the tumor and conus medullaris during the surgeryis vitallyimportant to avoid postoperative functional worsening. Overall functional recovery after surgerywas satisfactory.

Case 1：A 15-year-oldboy

Case 2：A 40-year-oldwoman

Case 3：A 67-year-oldman
All cases were referredto our hospital with palpable abdominal mass andlower extremity pain. Computedtomography (CT)andmagnetic resonance imaging(MRI)revealedlarge retroperitoneal masses. Cases 1 and 2 were dumbbell tumors. We performed surgical excision of all the tumors：the diagnosis was neurofibroma in Case 1, Perivascular epithelioidcell tumor(PEcoma)in Case 2, and liposarcoma in Case 3.

There have been no recurrences to date in Case 2 or Case 3：in Case 1 the tumor recurredwithin three months after initial surgery.

The patient is a 71-year-old female, who complained of progressive weakness of upper limbs and posterior neck pain. MRI showed a mass lesion behind the odontoid process, compressing the cord at the cranio-cervical junction, which showed high intensityon T2WI. The mass lesion presented with low intensityon T1WI and heterogeneous high intensityon T2WI. The patient underwent the
operation whose approach was lateral hemilaminectomyof C1 and C2 and transdural direction. The cyst cavitycontained a verydense yellowish fluid.

Synovial cyst at the atlanto-axial joint has some characteristics：age usuallyolder than 60 years, no trauma, no evidence of rheumatoid arthritis, and the mass lesion sometimes shows onlymarginal contrast enhancement on MRI.

This disease had an excellent outcome after posteriolateral surgical decompression.

We recommend the posteolateral and transdural approach to a C1/2 synovial cyst, if there is no C1/2 instability. Furthermore, the transdural approach enables easy advance to the synovial cyst with little cord retraction and never invites CSF leakage after subtotal incision of the dura including the cyst wall, because of broad and tight adhesion between the dura and synovial cyst.

[Introduction] We evaluated the cervical alignment before and after osteoplastic vertebrotomy for patients with cervical ossification of the posterior longitudinal ligament(OPLL).

[Methods] Osteoplastic vertebrotomy was performed on 8 patients, including 5 men and 3 women, ranging in age from 49 to 67 years(mean 60.1 years). The mean follow-up period was 1.5 years. Two or three level vertebrotomy was performed on 5 and 3 patients respectively. The percentage of the spinal canal diameter occupied by OPLL ranged from 23.1 to 63.4%(mean, 46.7%). Cervical lordotic angle, and C2-7 range of motion (ROM) were assessed before and after surgery. The alignment angle, range of intervertebral mobility, and disk height of segments operated upon was measured also.

[Results] The mean preoperative cervical lordotic angle and segmental alignment angle were 18.9 degrees and 0.4 degree, whereas these angles were 16.6 degrees and −0.5 degree postoperatively. The mean postoperative C2-7 ROM was diminished(35.1→27.5 degrees);however the range of intervertebral mobility was almost unchanged (3.63.3 degrees). The pre-and postoperative disk heights were 4.8mm and 4.0mm. Bony fusion was confirmed in all cases by postoperative computed tomography.

[Conclusion] The results suggest that the cervical alignment was preserved after osteoplastic vertebrotomy.

The purpose of this presentation is to discuss initial surgical outcomes of the K-method performed by one surgeon.

[Materials and Method] FromSep. 2005 to Dec. 2008, 95 patients were treated with the K-method and their clinical outcomes were evaluated. The mean age of these patients was 63.6 years. Their diagnoses were as follows;cervical spondylosis 71 cases, OPLL 18, and cervical disc herniation 6.
All were divided into two groups, the early cases (30) and the later cases (65).

[Results] The mean recovery rate of JOA score was 63.5%. The mean operating time was 173 minutes. The mean blood loss was 132g. The mean C2-C7 angle was 11.0° before surgery and 11.3° after surgery. The outcomes of later cases were better than those of early cases in all subjects. Major complications were as follows;deep wound infection 1 case, postoperative hematoma 3 cases, insufficiency of decompression 1 case. All cases were treated well by revision surgery.

[Discussion] I believe that the following are important to improve surgical outcomes 1) setting neck in neutral position, 2) preservation of posterior supporting complex, 3) strong hinged laminae and rigid fixation of laminae, spacer and spinous process, 4) acquiring skill of drilling by one hand and 5) keeping surgical site at rest for a while.

[Purpose] To report our experience of posterior decompression and reductive fixation for cervical spondylotic myelopathy with local kyphosis.

[Materials and methods] Twelve cervical spondylotic myelopathy patients with local kyphosis (ten males and two females) underwent laminoplastyand posterior fixation since April 2006, using pedicle screws and/or lateral mass screws for reduction of local kyphosis. The mean age was 60.5 years (range, 41-74) at the time of surgery.

[Results] There were no neurovascular complications during operation. Two patients suffered from radicular pain several days after surgery including C5 palsy.

[Conclusion] Posterior decompression and reductive fixation is useful for cervical spondylotic myelopathy with local kyphosis.

[Purpose] We report our experience in recent years using an ultrasonicosteotome which was very useful in spinal surgery.

[Materials and Methods] The cases were operated in the period from September 2004 to May 2009. The total number of the cases was 133, which includes 71 males and 62 females. The mean age was 57.4. The diseases include 86 cases of lumbar spinal canal stenosis, 14 of lumbar disc herniation, 2 of cervical disc herniation, 17 of cervical spondylomyelopathy, 3 of OPLL in cervical spine, 8 of spinal tumor and 3 of kyphotic change after thoracolumbar compression fracture. We applied an ultrasonic ostetome to all these cases. With this medical instrument, we perfomed laminectomy, laminoplasty, spinal shortening osteotomy, hard disc resection and so on.

[Results] By using an ultrasonic osteotome, we could perform all of the above safely and precisely as we planned, without damaging the spinal cord, nerve roots or any other soft tissue.

[Discussion and Conclusion] The ultrasonic osteotome seems to have the great advantage in spinal surgery of decreasing the incidence of injury to the spinal cord or nerves, compared to other such as air drill systems. In conclusion, the ultrasonic osteotome is a safe and useful medical instrument in spinal surgery.

[Introduction] VCS(Vascular Closure System) Clip Applier has been developed for performing rapid, precise and easy vascular anastomosis. The advantage of the VCS Clip Applier is also in applyingdural closure. It is convenient for spinal surgeons not only in cuttingdown the dura for intradural operation but also for treatingdura injured by accident. It is also of great benefit in preventingintradural adhesion and inflammation due to its non-penetrating features.

[Objective] Most cases of dural closure in spinal surgery are performed in a deep and narrow operatingfield. Moreover there are many difficult cases for anastomosis in injuries surroundingthe cutting edge of the bone. The aim of this presentation is to introduce the advantage of convenient tools which we developed for difficult anastomosis in dural closure usingthe VCS Clip Applier with safety and precision.

[Methods] One of the key points of performinganastomosis usingthe VCS Clip Applier is everting and picking up both edges of the anastomosis site by forceps prior to clipping. We developed special forceps for easy handlingand visibility. We also developed special hooks which can pull up the dura without heavy loadingat both edges of the dural incision or surroundingthe cuttingedg e of the bone. We prepared a few kinds of hooks with difficult angles for different approaching methods to the dura and different regions of dural closure.

[Results] Convenient tools which take easy handlingand visibility into consideration expand the adaptability and possibility of usingthe VCS Clip Applier for dural closure. It is a convenient tool for spinal surgeons not only for dural closure after intradural operations but also for treating accidental dura injury.

A 30-year-old male presented with a rare case of acute urinary retention without motor or sensory disturbance of lower extremities secondary to an L5/S1 lumbar disc herniation. He consulted the Otsu Municipal Hospital because of complete urinary retention which had started 3 days before admission. Additionally,he complained of constipation and impotence. Abnormality of the deep tendon reflexes,sciatica,or leg weakness were not noted. Emergent MRI and myelography revealed an L5/S1 disc herniation. Emergent surgical decompression was performed. The patient had almost fully recovered from complete urinary retention and impotence 2 months after the operation. When a syndrome like conus medullaris compression is encountered,the lower cauda equina should be examined as well as the conus level. Such cases require urgent diagnosis and treatment.

The purpose of this report is to demonstrate spontaneous resorption in recurrent lumbar herniated nucleus pulposus (HNP) after microdiscectomy (MD).

[Patients and methods] Twenty-nine (67%) of 47 cases of recurrent HNP after MD showed spontaneous resorption. Twenty-three spontaneous resorptions were observed in ipsilateral recurrence at the same level. The mean period from the MD to recurrence was 2.7 years. Recurrent HNPs mainly occurred at L4-5 or L5-S. The HNP images in T2-weighted (T2W) sagittal MRI were classified into 3 types. Type 1 showed no migration. Type 3 was more migrated than type 2. The signal intensities of HNP in T2W image were classified into 2 grades：low and high. The HNP area in T2W axial images was measured. A reduction rate of HNP was calculated from the area at recurrence and final follow-up.

[Results] Nine recurrent HNPs disappeared in a mean period of 2.2 years. The disappearance more frequently occurred in type 3. Fourteen HNPs reduced their size with 46.3% of mean reduction rate in a mean period of 7 months. Seven recurrent HNPs showed low intensity, 16 showed high. Five low intensities changed to high intensity and resulted in resorptions or disappearances.

[Conclusions] Spontaneous resorption was observed in patients with recurrent HNP after microdiscectomy as well as primary HNP. Conservative treatment will be recommended as an option among strategies for recurrent HNP.

[Objectives] To report our technique of recapping-laminoplasty for Lumbar Spinal Canal Stenosis and clinical study of postoperative bony fusion rate of the recapped laminae.

[Technique] Through a spinous process splitting approach, the laminae are cut bilaterally with a unique trapezium cutting line, using an original bone chisel with a stopper which decreases the risk of dural tear or nerve injury. The laminae are then removed and decompression is done. The laminae are recapped, and for early fixation, the anchoring hall on the cutting line is filled with a small quantity of bone cement. Finally, a local bone graft is done posterior to the cutting line.

[Materials & Methods] In 2007, recapping-laminoplasty was performed in 90 cases. We selected 35 cases in which CT was examined more than 9 months after operation, and evaluated the bony fusion rate of the recapped laminae.

[Results] In 33 cases the recapped laminae was fused bilaterally, in 1 case unilaterally, and in 1 case not fused.

[Discussion and Conclusion] We perform recapping-laminoplasty by a simple technique using a unique cutting line and an original bone chisel and bone cement, as a standard method for LSCS without necessity of fixation or stabilization. This method achieved a high bony fusion rate of the recapped laminae.

[Purpose] To report our experience of C1 lateral mass screw insertion technique in posterior upper cervical fixation.

[Materials and Methods] 24 patients underwent this procedure since March 2004. The disorders were AAS in 9 patients, odontoid fracture and C2 bodyfracture in 8, retroodontoid mass in 3, os odontoideum in 2, and AARF with cerebral palsyin 2. C1 lateral mass screws were placed, using the technique described byGoel & Harms and Hong, Tan. Under fluoroscopyand navigation system, C1 lateral mass screws were inserted using microscopy.

[Results] All C1 screws were placed without incident, and no neurological or vascular complications were encountered.

[Conclusion] Preoperative evaluation of anatomical structure and development of the posterior arch and lateral mass of the atlas are necessaryfor insertion of a C1 lateral mass screw. During intraoperative positioning of the cervical spine, atlantoaxial alignment is especiallyimportant. A navigation system is useful for insertion of a C1 lateral mass screw.

[Purpose] To report surgical technique and results of reduction and fixation for lumbar spondylolisthesis with Aesculap Spine S4 spinal system SRI.

[Material] Isthmic(n=4), degenerative(n=3), dysplastic spondylolisthesis(n=1), three males and five females with average age of 59 y/o were operated.

[Surgical technique] After total facetectomy the SRI attachment was set to the medial side of the S4 polyaxial screw. Reduction of the spondylolisthesis was performed after distraction of the intervertebral space under fluoroscopy. The bone graft and Prospace implant were inserted into the disc space through the lateral foraminal space.

[Results] L3/4 fenestration was performed in 2 cases, L3/4 PLIF in 1 case, L4/5 PLIF in 5 cases, and L5/S1 PLIF in 4 cases. JOA score 12.4±4.4 before operation was improved to 25.0±4.6 after operation, average recovery rate：75.9%. % slip 29.1±11.6% before operation was improved to 0.8±2.3% after operation, slip angle −6.6±7.3°before operation to 8.0±2.4°after operation. Operation time and intra-operative blood loss were 221±48min, and 538±303g respectively. Reoperation was performed due to the dislodgement of the grafted bone in one case. Transient aggravation of numbness in one case recovered after several months.

[Discussion] Reduction of the spondylolisthesis can correct the sagittal lumbo-sacral alignment and increase the fusion area. To decrease the risk of root impairment, total facetectomy and enough decompression of the root is important. This SRI technique seems to be useful for reducing the spondylolisthesis effectively and safely.

A technique ofMeshplatingwas performed on 18 patients with spondylolytic spondylolisthesis and on 9 patients with spondylolysis. TheMeshplatewas made of Titanium mesh and composed of a cylinder part and a plate part. TheMeshplatingwas the method of spondylolysis repair, filling the cylinder part with cancellous bone and attaching the plate part to the lamina with mini screws. It was performed by inside-repair for all cases of spondylolysis and 9 cases of spondylolytic spondylolithesis, and by the outside-repair for 13 cases of spondylolytic spondylolithesis. In all cases, the Meshplated laminae were fixed by the modified Scott method; pedicle screws and wire fixation. The mean follow-up period was 39 months. The results seemed to be excellent with a mean JOA score improvement of 80%. There was no sign of pseudoarthrosis, adjacent segment degeneration, or neurological complication in spite of some implant failures. The outside-repair provided less stability of the Meshplated lamina than the inside-repair, because the lamina was completely apart from surrounding soft tissues. It may be effective to connect the Meshplated lamina with the caudal spinous process by wiring or spinous process plates when stability is insufficient.

Endoscopic spinal operations are indicated for lumbar disk herniation, lumbar canal stenosis and lumbar degenerative spondylolisthesis. This is minimally invasive surgery applied recently to cervical diseases. However, although the procedure is highly useful as minimally invasive surgery, it brings problems such as a large learning curve. In order to deal with such problems, it is important to know the pitfalls of endoscopic surgery. In this paper, we describe the pitfalls and problems associatedwith this procedure, using the cases operatedat our hospital.

MIS-PLIF is becoming widespreadin spinal surgery. We performedMIS-PLIF for lumbar canal stenosis using a spinous process splitting approach. The authors describe such a surgical technique andevaluate the clinical outcomes of this procedure. After separating the split spinous prosess into two halves, it is easy to performe decompression and PLIF. MIS-PLIF using a spinous process splitting approach is a less invasive procedure andhas ledto goodclinical results.

Recent advances in instrumentation surgery of the cervical spine have enabled us to obtain rigid internal fixation andshortening of postoperative immobilization of the neck. Simultaneously, however, we have to face the possibility of serious complications including vertebral artery injury.
For improving the accuracy andsafety of posterior instrumentation surgery of the cervical spine, we have recently introduced several techniques. In the present article, we describe 1) preoperative evaluation of the vertebral artery with 3D CT angiography, 2) fusion image technique of CT and MRA for evaluating the vertebral artery in patients with renal dysfunction, 3) preoperative surgical simulation andintraoperative navigation using a 3D full-scale model, and 4) use of an angle device andaccurate fluoroscopic imaging of the pedicle axis view for improving the accurate of the insertion of C3-C6 pedicle screws.