Surgical Technique for Spine and Spinal Nerves
Vol.11 No.1(2009)

Main Theme 1: My Own Invention for Low-Invasive Spinal Surgery

Transvertebral Anterior Cervical Micro-Decompression Hidetoshi MURATA, et al. Anterior cervical fusion surgery can cause fusion complications such as range of motion(ROM) restriction and degenerative change of the adjacent vertebral body. Disc removal is hesitated in young patients having a healthy disc and maintaining ROM. We adopted a modification of the transvertebral anterior micro-decompression(TVAD) technique for local cord compression or foraminal stenosis. The decompression was achieved by drilling a keyhole in the upper vertebral body, and most of the disc tissue and bony structure such as the vertebral body and Luschka joint were preserved. The most recent fifteen patients were prospectively analyzed for this procedure. TVAD was applied in 7 cases of cervical disc hernia(DH), and 8 cases of cervical spondylosis. This procedure was evaluated for neurological assessment, recurrence, cervical alignment, range of motion(ROM), and disc height. Neurological improvement and decompression were well achieved in all cases. None of these cases recurred. The cervical alignment and ROM were maintained, though the disc height slightly decreased especially in DH. TVAD is an effective treatment for local compression. It avoids unnecessary violation of the disc space and much of the bony stabilizers, and preserves physiological cervical function. The short-term results of this technique are quite encouraging.

Anterior Approach for the Cervical OPLL(Ossified Posterior Longitudinal Ligament) Masahito HARA, et al. In most cases of cervical OPLL, posterior decompression by double door laminoplasty was adopted in our institute. However, in cervical kyphotic cases or short segment OPLL cases, we selected the anterior approach. We performed 3 different anterior approaches, namely an osteoplastic vertebrotomy, William-Isu method, and transvertebral key-hole surgery. 　There were 8 cases of osteoplastic vertebrotomy for the continuous or mixed type OPLL spread through 3 to 4 vertebrae, 5 cases of William-Isu method for the circumscribed type of OPLL and 2 cases of transvertebral approach for small OPLL causing the radiculopathy. There was no postoperative neurological deterioration in any anterior approach. However, 2 of in the cases of osteoplastic vertebrotomy had CSF leakage, which subsided over several days. We describe these anterior approaches in detail and mainly discuss the osteoplastic vertebrotomy. OPLL resection by osteoplastic vertebrotomy is safe because of the wide operative field. As the most of the vertebral bone is returned, it is thought to be very useful in respect of minimal bony defect. Although the postoperative spinal column changes would have

Unilateral Cervical Open-Door Laminoplasty with Titanium Miniplates through Hydroxyapatite Spacers Satoshi TANAKA, et al. Cervical laminoplasty for cervical stenotic myelopathy has been performed using various modalities. We describe unilateral open-door laminoplasty with titanium miniplates through hydroxyapatite spacers. Sixteen patients with cervical spondylotic myelopathy or radiculopathy and 2 with ossification of the posterior longitudinal ligament were treated by this procedure. The patient was placed on the table in a prone position with the head kept neutral. A midline skin incision 4 or 5 cm long was made and a paramedian approach was used to avoid injuring the nuchal ligament. The more affected unilateral side of the laminae was exposed. The spinous processes and supra- and intraspinous ligaments were left intact. A 4 mm-wide gutter near the intervertebral joint was made by a 3-mm diamond burr. The opened laminae were fixed with hydroxyapatite spacers(8 mm wide and 8 mm long) with a hole through which the 6 holes-titanium miniplates were passed. Four 5 mm-titanium screws were used in each lamina. All 18 patients were evaluated according to the Japanese Orthopaedic Association score and the mean recovery rate by the Hirabayashi Method was 43.9%. Our method for unilateral open-door laminoplasty seems to be less invasive, but still gives tight fixation and adequate decompression for cervical stenosis.

Main Theme 1: My Own Invention for Low-Invasive Spinal Surgery Surgical Outcome of Posterior Approach in Patients with Thoracic Myelopathy Due to Disc Herniation Taketoshi KUSHIDA, et al. [Objectives] We have developed a new posterior approach using a microscope in surgery for central or paracentral thoracic disc herniation with myelopathy. We report here the surgical procedure and clinical outcome. [Subjects] The present study includes 14 patients(8 males and 6 females, ages 33-69 years, 48.3 years old on average) with thoracic disc herniation whose extruded disc fragments were removed by posterior approach. [Operation Procedure] Ipsilateral laminectomy was performed through unilateral approach. The inner sides of the contralateral laminae were drilled due to moving the dural tube posteriorly. The facetectomy made some space laterally and the posterolateral margins of the upper and lower vertebral bodies were exposed. Finally the extruded disc fragments were removed from the lateral side using an air drill. [Results] No major complications such as paralysis were observed. The amount of intraoperative bleeding was 113 ml on average and the duration of operation was 2 hours and 30 minutes on average. The JOA score was improved from 6.1 to 8.3 and the Hirabayashi recovery rate was 64.1%. [Conclusion] The posterior approach using a surgical microscope is safe and effective because this method is less invasive and has few postoperative complications

Thoracic Anterior Spinal Surgery by Small Incision Hideo HOSOE, et al. Classically, sternotomy and open thoracotomy are standard procedures for anterior thoracic lesions such as OPLL and herniated disc, but these operations sometimes have postoperative complications such as severe pain and deterioration of respiration and shoulder function. Sixteen patients(11 men, 5 women, average age of 54.8 years) were operated between T2/3-T12/L1. The reasons for surgery were as follows: OPLL(n=6), herniated disc(n=6) and bone grafting for trauma(n=4). The anterior surgical procedure was performed via an incision only 4 to 8 cm long. The mean operative time was 229 minutes, and mean estimated blood loss was 176 ml. Patients who underwent mini-open anterior thoracic surgery had a lower CRP, less postoperative pain, good recovery of respiratory function and less deterioration of shoulder function. This procedure for localized anterior thoracic lesions is a good alternative to classic sternotomy or thoracotomy.

Minimally Invasive Spine Surgery for Lumbar Revision Surgery Koji SATOH, et al. We performed MIS-PLIF by hemi approach and bilateral decompression through a small incision in 241 cases of　 lumbar spinal canal stenosis(LSCS) since 2003. I thought that the operation skill was stable after 200 cases and applied it to　 re-operation cases that seemed difficult before. I reviewed whether a re-operation was possible by minimally invasive spine　 surgery in 8 cases. 3 cases of re-stenosis underwent revision by MIS-PLIF. 4 cases if adjacent segment disease 4 cases underwent　 revision by MED. One non-union case was treated by MIS-TLIF. Operating time was 1.5 times that of a normal case. Blood loss was very little. Complications were one neurological defect and one dural tear. I can carefully apply the MISS technique　 to salvage surgery.

Main Theme 2: My Own Invention for Avoidance of Complications An Evaluation of Outcomes of Atlanto-Axial Fixation Using Non-Absorbable Tape Futoshi SUETSUNA, et al. Purpose: To evaluate the efficacy and possible complications of AAF using non-absorbable polyethylene tape. Methods: 18 patients underwent AAF for atlanto-axial instability(AAI). Group 1 included 5 patients with AAF using tape and transarticular screws. Group 2 included 9 patients with AAF using titanium wires and transarticular screws. Group 3 included 4 patients with AAF using only tape. Radiographic parameters included fusion rate, atlanto-axial angle(AAA), and ADI. Results: Fusion rate was 100%. The average post-operative and follow-up AAA were 27.0 degrees and 26.8 degrees in group 1, 26.5 degrees and 26.3 degrees in group 2 and 29 degrees and 25.0 degrees in group 3. The average pre-operative, post-operative and follow-up ADI were 9.0 mm, 1.6 mm and 1.5 mm in group 1, 8.9 mm, 2.2 mm and 2.2 mm in group 2 and 8.8 mm, 2.6 mm and 5.5 mm in group 3. Three cases showed loosening of the titanium wires. Conclusion: Group 1 and group 2 demonstrated reliable fusion and spinal correction. Group 2, however, had cases of loosening of the titanium wire and loss of correction was noted in group 3. AAF using tape and transarticular screws was an effective and safe treatment for AAI.

Usefulness of Ultrasonic Bone Scalpel in Posterior Microendoscopic Surgery Yukihiro NAKAGAWA, et al. Introduction: Microendoscopic surgery(MED) has been applied for various spinal pathologies which required neural decompression. To perform MED surgery safely and adequately, we use an ultrasonic bone scalpel. Purpose: To report the usefulness of the ultrasonic bone scalpel in MED surgery. Materials and methods: Decompression surgery for lumbar spinal stenosis, cervical foraminotomy for cervical radiculopathy and cervical laminotomy for cervical myelopathy were candidates for use of the ultrasonic bone scalpel in MED surgery. Results: Bony resection and decompression close to neural tissue were successfully performed in all operations. Obvious venous bleeding was not encountered. No intraoperative complications including neural injury happened. Discussion: To perform MED surgery for various pathologies safely, improvements of surgical instruments were required. By using the ultrasonic bone scalpel, bony resection close to neural tissue can be performed safely without excessive bleeding. Conclusion: The ultrasonic bone scalpel enables as to perform MED more safely and effectively.

Main Theme 2: My Own Invention for Spinal Tumor and Vascular Surgery Surgery of Foix-Alajouanine Syndrome Masanori ITO, et al. Objective: To highlight the role of exploration and necrotomy for the diagnosis and treatment of two cases with Foix-Alajouanine syndrome(subacute necrotizing myelopathy). Method and Results: Case 1: A 62 year-old female suffered severe occipitalgia followed by progressive tetraparesis and bulbar symptoms. T2-weighted MRI showed diffuse intramedullary hyperintensity in the medulla oblongata extending downward to the upper thoracic cord. Ring enhancement was localized at the C2 level. Surgical verification(C1-3 laminoplasty) showed sparse arterial distribution, and collapsed and partially thrombosed veins on the dorsal surface of the cord. Midline myelotomy yielded creamy fluid that proved to be necrotic tissue. Histological examination showed that the venous wall was thickened with lymphocytic infiltration. Her tetraparesis showed mild improvement postoperatively with marked resolution of the intramedullary hyperintensity on MR imaging. Cerebral angiography revealed a posterior fossa dural arteriovenous fisutula(dAVF) without venous drainage via the perimedullary vein. The dAVF was completely obliterated by transvenous coil embolization. Case 2; A 78 year-old man presented with progressive paraplegia over 2 months. No intracranial or spinal arteriorvenous malformations or fistulae were detected by cerebral and spinal angiography. MRI and operative findings showed very similar findings to those of case 1. Discussion and Conclusion: Foix-Alajouanine syndrome can be caused by dural AFV or has been rarely reported in the absence of dAVF or abnormal spinal surface vessels(10 Schwarz, 1997, 9 Rodoriguez, 2005). In cases with T2-high cord swelling and no serpentine vessels with enhancement on MRI, spinal cord biopsy is recommended. Surgical exploration in our cases revealed no tortuous vessels but thrombosed vessels in the dorsal spinal cord and intramedullary necrotic tissue containing pus-like material. Surgical mass reduction by removal of necrotic tissue (necrotomy) yielded clinical improvement and avoided further clinical aggravation.

Total En Bloc Spondylectomy for Spinal Tumors with Epidural Cord Compression ―How to Remove the Vertebral Tumor En Bloc without Injuring the Spinal Cord― Norio KAWAHARA, et al. It is dangerous to the spinal cord to dissect using a Penfield dissector between the pseudocapsule of the epidural tumor and the adherent anterior aspect of the dural tube, because the spinal cord is already compressed by the epidural tumor. In order to remove the vertebral tumor en bloc without injuring the spinal cord, 1) the anterior column was cut at the safe margins above and below the epidural tumor using a T-saw, 2) the tumor vertebra was pushed away from the dural tube, which relieved the spinal cord compression, and 3) the adhesion was safely dissected using a Penfield dissector between the pseudocapsule of the epidural tumor and the anterior aspect of the dural tube. Total en bloc spondylectomy was performed on 18 > patients with spinal tumors who had epidural compression at the levels of T2-L1. There was no violation of the pseudocapsule of the epidural tumor in any resected specimen. No patient had neurologic degradation after operation. This procedure allows oncologic en bloc vertebral resection without injuring the spinal cord in patients with epidural tumor compression.

Main Theme 3: My Own Invention for Instrumentation Reduction with SRI for Spondylolisthesis Yurito UEDA, et al. [Purpose] The purpose of this study is to evaluate the advantages of using the SOCON system and SRI(Spondylolisthesis Reduction Instrument) to reduce lumbar spinal spondylolisthesis. [Materials and method] We reduced spondylolisthesis by the SRI and SOCON System in 40 cases(men 13, women 27 cases), and did not reduce but fused by other instrumentation systems in 11 cases(men 2, women 9 cases). We evaluated the preoperative and postoperative %slip, slip angle, and JOA score of the two groups. [Result] Preoperative %slip of the reduction group was 22.5±1.4°and of the non-reduction group 23.9±4.4°. Postoperative %slip of the reduction group was 6.1±0.8°and of the non-reduction group was 12.7±3.3°. There were no significant difference between two groups in t-test preoperatively, but there was a significant difference (P=0.028) postoperatively. For slip angle and JOA score, there were no statistical significant differences between the two groups. [Discussion] In the conventional reduction method, the slipped spine was pulled up only by the linear posterior force to the pedicle screw. Therefore it was difficult to reduce the lesions quantitatively, and there was a higher possibility of a screw avulsion, because they needed strong orthodontic force. The SRI used a link mechanism expertly, adding a distraction force, and then introfuding a reduction force in a cycloid pattern. Also the SOCON System with SRI could materialize the quantitative reduction of lumbar spondylolisthesis. [Conclusion] Reduction of lumbar spondylolisthesis was certainly provided by the use of SRI and SOCON System, but there was no statistical difference in clinical result between the reduced and non-reduced groups, and this needs further examination.

Colorado II Increases the Fusion Rate at L5 / S in Multi-Segmental Lumbosacral Fusion Akiyoshi YAMAZAKI, et al. Thirty patients who had more than 3 level lumbar fusion including the sacrum with Colorado II(S1 pedicle screws(PS) combined with ala screws) were reviewed, comparing them to 11 patients who had more than 3 level lumbar fusion including the sacrum with S1 pedicle screw fixation only. The fusion rate was compared between the 2 groups. In Colorado II, the overall fusion rate was 66%. Non-fused segments were L5/S in 1 patient and the most cranial levels(MCL) in 10 patients. On the other hand, the overall fusion rate was 73% in S1 PS. Non-fused segments were L5/S in 2 patients and MCL in 1 patient. At MCL, the fusion rate was 80% in Colorado II and 91% in S1 PS, while at L5/S, it was 97% and 82%, respectively. Moreover, if limited to the patients with non-union, it was 0% in Colorado II and 67% in S1 PS at MCL, and 90% and 33% at L5/S, respectively. Although in Colorado II the fusion rate at MCL was remarkably decreased, it was increased at L5/S. Clinical problems such as pain mainly come from delayed union at L5/S rather than MCL. Therefore it is more important to pay attention to L5/S rather than MCL.

Postoperative Results of Infectious Spondylitis Treated with Spinal Fusion Using a Spinous Process Plate(S-Plate) Reiko FUJITA, et al. <Purpose>A spinous process plate developed in our hospital(S-plate) has been used for in situ fusion. The clinical results of infectious spondylitis treated by this S-plate were studied. <Materials>Since 1994, the S-plate was applied to 10 patients with infectious spondylitis. The average age was 65.1 years. The mean follow up period was 2 years 3 months. All cases were resistant to conservative therapy. The level treated was cervical spine in 1, thoracic spine in 1, and lumbar spine in 8 patients. The clinical results of 5 patients followed up for more than one year were studied. The causative bacteria were several. Single stage operation was done in 7 cases and 2-stage operation was done in 3 cases. The surgery was anterior curettage and reconstruction with a Titanium mesh followed by posterior spinal fusion with S-plate in all cases. <Results>All cases showed good results and bony union was accomplished. The average JOA score improved from 10.8 to 23, and the recovery ratio was 67%. There was no complication due to the S-plate. <Discussion & conclusion>The S-plate is small and easy to apply, and the results were good. The S-plate seemed to be useful for infectious spondylitis.

The New Surgical Techniques for Reconstruction of Anterior Support of Collapsed Vertebral Body Following Osteoporotic Compression Fracture of the Thoracolumbar Spine Kenichi CHATANI, et al. [Purpose] We report two new surgical techniques for reconstruction of anterior support of a collapsed vertebral body following osteoporotic compression fracture of the thoracolumbar spine. [Surgical techniques and materials] For pseudoarthrosis of the fractured vertebral body, we make a fenestra on the post-lateral wall of the body bilaterally and insert cages to the body through the fenestrae. The other technique is for the instability of the adjacent level following wedge deformity of the fractured vertebral body. We perform intervertebral fusion with cages through a transpedicular approach, in which the medial walls of the pedicles are preserved. Both techniques are reinforced with posterior instrumentation. The former was indicated for three cases(L1 or L2) and the latter was indicated for two cases(T12). The mean periods of postoperative follow-up were 28 and 24 months. [Results] There was no neurological complication. Postoperatively, some correction of kyphosis and bony fusion were obtained and gait disturbance disappeared in all cases. [Conclusion] Anterior supports, destroyed by vertebral body collapse, were well reconstructed and satisfactory outcomes were obtained by our surgical techniques. Their great advantage was that the insertion routes of the cages were out of the spinal canal.

Main Theme 3: My Own Invention for Screw Insertion Our Method to Identify the Entry Point of Pedicle Screws in the Lumbar Spine and Sacrum Naoaki KASAI, et al. (Purpose) To study the safety of our method of identifying the entry point of pedicle screws in the lumbar spine and sacrum. (Material and Methods) 107 consecutive patients underwent PLIF using our method between Apr. 2007 and Apr. 2008. The entry point was identified as the apex of the triangular area‘( harbor'named by KF) near the accessory process at the base of the transverse process at L1-L5. A small dimple distally adjacent to the S1 facet was used as the entry point at the sacrum. The placements were classified as A: pedicle screws completely inside of the pedicle with or without contacting the cortex of the pedicle wall. B: pedicle screws laterally out of the pedicle more than 50%. C: pedicle screws inside the spinal canal more than 10%. (Results) A total of 574 pedicle screws were analyzed. A was 98.4%. B was 1.39%. C was 0.17%. (Discussion) Our method has two advantages. Less exposure lateral to facet joints may favor less blood loss. Preserving the cortex of the posterior wall may provide stronger grip for pedicle screws. (Conclusion) This method of identifying entry points of pedicle screws in both the lumbar spine and sacrum is useful in promoting safe pedicle screwing.

Main Theme 4: Perspectives for Spinal Surgery Usefulness and Future Perspective of Spinal Cord Stimulation in Orthopedic Patients Hajime HOSHINO, et al. (Objective) To examine the usefulness and future perspective of spinal cord stimulation(SCS) for the treatment of intractable neuropathic pain in orthopedic patients. (Subjects) The study involved a total of ten patients-seven male and three female-with a mean age of 60.2 years. Two patients had cervical cord injury, two were postoperative patients with cervical spondylotic myelopathy, one postoperative with OYL in the thoracolumbar spine, three with multiply-operated back, one with adhesive arachnoiditis after lumbar laminectomy, and one with causalgia of the lower limbs. (Methods) All patients underwent percutaneous or open laminectomy, and a stimulating electrode was placed in the epidural space. Efficacy was evaluated with a verbal pain rating score. (Results) SCS was highly effective in one patient, effective in six, slightly effective in two, and not effective in one. (Discussion) The present results suggest that SCS may be a useful therapeutic procedure for intractable neuropathic pain in orthopedic patients. SCS will play a greater role in the orthopedic field. In patients with cervical spondylotic myelopathy who are expected to experience less improvement after surgery(irreversible conditions), placement of an epidural stimulating electrode together with a posterior approach may be a reversible, less invasive therapeutic procedure for greater postoperative improvement.

Significance of Evaluation with Stabilometry for Cervical Myelopathy Patients Tatsuya OHTONARI, et al. [Objective] We evaluated the usefulness of stabilometry for cervical myelopathy patients. [Methods] Of 49 cervical myelopathy patients who had operation, 37 (25 males and 12 females, mean age 62.8±10.3 years) underwent examination in a follow-up period. The operations were performed with open-door laminoplasty. Preoperative and postoperative stabilometry and conventional Japan Orthopaedics Association score(JOA score) were examined in all cases. Environmental Area (EA) and Locus Length per Environmental Area(L/EA) on closing eyes were used as parameters of evaluation. [Results] Postoperative mean EA and L/EA revealed no significant improvement. In 28 cases with decreased JOA score in the lower limbs before surgery, the score improved in 19 cases and worsened or showed no change in 9 cases after surgery. Consequently, there was a significant improvement of EA(p=0.008) and L/EA(p=0.024) after surgery in the former. [Conclusion] This study proved the relation between the improvement of the palsy and postural stability in cervical myelopathy patients with palsy in the lower limbs. In this respect, stabilometry was useful in the evaluation of postural stability for cervical myelopathy patients.

Perspective for Spinal Surgery by Spinal Instrumentation Surgeon Kiyoshi KUMANO The invention of the Harrington rod spinal instrumentation in 1961 monumentally changed the development of spinal surgery. Since then over past forty years not only the medical fields but the medical environment has drastically changed. The paternalism of doctor-patient relationship has declined and patients' rights and consensus between patients and doctors are now emphasized. Transparency in medical processes and safety of medical procedures are key issues as well as cost-benefit analysis. There is a great tendency in spinal surgery towards minimally invasive surgery. At the same time spinal instrumentation has been increasingly used in various types of spinal surgery. Medicine always bears a close relationship with the social economy. They had to receive funds and contributions from the medical industry to enable their continuation. In medicine cost-benefit analysis is essential. When we study perspectives for spinal surgery we have to recognize that this relationship between medicine and medical industry is highly influential. ［Conclusion］A Spinal surgery will continue to pursue maximum safety, reliable results and a good cost-benefit ratio for all procedures. Developing new technology will continue that its outlook is bright.

Free Papers 1: Tumors and Vascular Disorders Four Cases of Idiopathic Thoracic Intradural Arachnoid Cyst Yoshifumi KAWANABE, et al. Spinal intradural arachnoid cysts are relatively uncommon and usually asymptomatic but may produce symptoms by compressing the spinal cord or nerve roots suddenly or progressively. We present four cases of idiopathic intradural thoracic arachnoid cysts and discuss the strategy of treatment. All patients experienced spastic gait and hypesthesia/hypalgesia/thermohypeesthesia below the level of each thoracic lesion. No patient had a history of spinal trauma or meningitis. In each patient magnetic resonance imaging(MRI) revealed a syrinx cavity and an intradural posterior fluid collection compressing the spinal cord. There was no evidence of spinal cord tumors, arachnoiditis, Chiari malformation, tethered cord or hydrocephalus. All patients were treated by microsurgical resection of the arachnoid cyst; syringo-subarachnoid shunt was added in one case. Postoperative neurological improvement was documented in all cases. Follow-up MRI demonstrated the disappearance of the arachnoid cyst and a significant decrease in the size of the syrinx cavity in all patients. Although intradural arachnoid cysts may cause progressive myelopathy, the postoperative prognosis is good if the operation is performed prior to appearance of severe neurologic deficits. Complete surgical excision of the cysts may be the best choice of treatment, and wide fenestration and shunting of the cyst to the peritoneum, pleural cavity or right atrium may be the modalities of choice.

Fibrin Glue Filling for Symptomatic Sacral Perineurial Cyst Souichi OHTA Surgical intervention for symptomatic sacral perineural cyst is still debated. In our case, a 60-year-old man consulted us about gradually worsening of right lower leg pain for 6 months. Two months after the first consultation, intermittent claudication appeared and he could stand for only 5 minutes. CTM and MRI examination showed some perineural cysts in the sacrum. We performed laminectomy and opened the cyst wall. Only one nerve was found in the cyst. We also found a leak of CSF through the perineural communication between the cyst and the subarachnoid space at the proximal part of the cyst. It was difficult to close the communication without nerve compression and to plicate the cyst wall without closure of the communication. Therefore we performed filling of the cyst with fibrin glue, continually aspirating CSF. Ambulation was started 2 days after operation and preoperative symptoms had disappeared. However, they recurred partially 5 days after operation, but CTM examination showed no communication between the cyst and the subarachnoid space. Symptoms completely disappeared within a few more months. There was no symptom 2.5 years after operation. MRI examination showed no recurrence of the cyst formation. Fibrin glue filling with laminectomy would be one choice for symptomatic sacral perineurial cyst.

S1 Radiculopathy Probably Due to Dural Arteriovenous Fistulae ―Case Report― Eiichiro HONDA, et al. Many reports of myelopathy due to dural arteriovenous fistulae(DAVF) have recently appeared. However, radicular pain due to DAVF in the lumbar spine has rarely seen. We report a 26-year-old men presenting with radicular pain along the right S1 nerve root. The first symptoms were dull pain and mild weakness in the right leg, which deteriorated for about 2 months. The radicular pain developed close to evening. MRI findings resembled a sequestered disk hernia or hematoma associated with disk herniation under the S1 nerve root. Operative findings revealed a mild disk hernia at L5/S1 and two large vessels connecting to the S1 nerve root with a reddish pouch along the distal side. These vessels were coagulated and cut off. Their histological diagnosis seemed to be DAVF. Conclusion: Lower DAVF is almost always supplied from the lateral sacral artery through the iliac artery, which invites myelopathy at the level of the conus and lower thoracic cord. We present the only case with radiculopathy due to DAVF in the lower lumbar area, whose causes ara related to trauma (repeated lumbar tap and root injury as surgical complications) or an anomaly such as spina bifida. In imaging diagnosis, DAVF detection using angiography and MRI is difficult in the lumbar region, compared to the cervical and thoracic regions. For this reason, lumbar DAVF may misdiagnose a light disk herniation or an unknown lesion. Coagulating and cutting the draining vein is a surgically better treatment.

Intraoperative Microdoppler Ultrasound and Angiography Monitoring for Spinal Vascular Disease ―Report of 2 Cases ― Keishi TSUNODA, et al. Purpose: Intraoperative spinal microdoppler ultrasound and angiography monitoring have rarely been reported. In this report, we describe our experience with the use of combined intraoperative microdoppler ultrasound and intraoperative angiography in spinal vascular disease. Case 1: A 78-year-old male with cervical disc hernia experienced vertebrobasilar insufficiency when he rotated his head to the right side. We performed an anterior approach to remove the calcified disc hernia. Intraoperative microdoppler ultrasound guidance was useful in identifying the vertebral artery in real time, while the intraoperative angiography was useful in making the diagnosis of decompression of the vertebral artery. Case 2: A 58-year-old female with craniocervical junction spinal dural AVF suffered from progressive myelopathy. We performed the posterior approach and the draining vein was obliterated. Apart from identifying the vein in real time, the intraoperative microdoppler ultrasound together with the intraoperative angiography were useful in ascertaining the obliteration of the fistula. In this case, the intraoperative position was prone, so an ultra-long sheath was used for performing transfemoral angiography. Discussion: Intraoperative diagnosis is important for performing surgical procedures reliably and safely. Intraoperative microdoppler ultrasound and intraoperative angiography can provide reliable results in cases of spinal vascular disease. Although intraoperative angiography in the prone position is complicated, the use of an ultra-long sheath ensures that the procedure can be performed safely.

Anterior and Posterior Approach for Dumbbell-Shaped Schwannoma at Cervical and Thoracic Levels ―Case Report ― Kenji ENDO, et al. We performed tumorectomy on three cases of dumbbell-shaped schwannoma through anterior and posterior approach. Two cases ware cervical scwannoma and the third case was thoracic scwannoma. In the cases of cervical lesion, we did posterior decomopression and resection of the tumor from the dorsal rami of the cervical nerve root by hemi-laminectomy and anterior removal of the tumor through the lateral side of the sterno-claudo-mastoideus. In the thoracic case, we did posterior decompression and resection and anterior endoscopic removal of the tumor. The almost dumbbell-shaped schwannoma could only be removed through the posterior approach, even if a small amount of tumor remained, it is a benign tumor and the later problems may be slight. However, in some Eden II or III type shaped tumors, these anterior and posterior methods are useful in terms of total resection of tumor mass and safety from secondary nerve damage.

Diagnostic Dilemma and Surgical Strategy in Spinal Cord Tumors ―Retrospective Analysis of 66 Cases ― Toshihiro TAKAMI, et al. OBJECTIVE: Although careful diagnostic imaging is always performed in surgery for spinal cord tumors, the preoperative interpretation of tumor pathology is not always straightforward. In the present study, diagnostic dilemmas in spinal cord tumors were studied retrospectively based on intraoperative findings and pathological diagnosis. PATIENTS AND METHODS: The patient record included a total of 66 cases of spinal cord tumors, which had been operated over the past 5 years. The tumors were classified into 23 intramedullary, 38 extramedullary and 5 extradural tumors based on their location. When preoperative diagnostic imaging fails to determine the tumor pathology, the decision of tumor resection was made based on careful inspection of the tumor and intraoperative examination of bioptic frozen sections. RESULTS AND CONCLUSION: In a total of 14 cases (21%), diagnostic imaging failed to determine the tumor pathology before surgery. Those 14 cases included 11 of 23 intramedullary tumors(48%), 2 of 38 extramedullary tumors(5%) and 1 of 5 extradural tumors(20%). Their pathological diagnosis made after surgery were 6 ependymal tumors(2 ependymomas, 2 subependymomas and 2 myxopapillary ependymomas), 2 astrocytomas, 2 germinomas, 2 schwannomas, 1 ependymal cyst and 1 peripheral PNET. The failure of imaging diagnosis before surgery is due to the non-typical tumor characteristics, as indistinct tumor margin or the pathological tumor rarity. Even in such a case, careful inspection of the interface between the tumor and normal neural tissue is prerequisite to accomplish safe and radical resection of the tumor.

Free Papers 2: Lumbar Spine 1 Chronic Expanding Hematoma(CEH)in the Second Lumbar Spinal Canal ― A Case Report― Hiromu YAMAMOTO, et al. Chronic expanding hematoma(CEH) was first reported by Friedlander in 1968 as a hematoma expanding in the calf muscle for more than 3 years. We now present a rare case of a 69-year-old male who suffered from motor weakness of the lower extremities and difficulty in walking due to CEH in the second lumbar spinal canal combined with lumbar spinal canal stenosis between L3 and L5. At his first visit to our clinic, a small space occupying lesion was found in the spinal canal at L2/3 level on MRI and diagnosed as lumbar disc herniation. However, on admission two and half years later, the lesion was confirmed to have gradually grown in size from 10x10 mm to 20x20 mm and to have induced scalloping deformity at the L2 vertebral body. It was therefore diagnosed as a benign tumor preoperatively. During operation, the lesion was confirmed to be covered with thin connective tissue and could easily be removed from the surrounding structures despite adhesion. The content was iron-like black, dry, and fragile. The pathological diagnosis was degenerated hematoma. In conclusion, CEH can be one of the space occupying lesions which may grow chronically in the spinal canal.

Clinical Results of Muscle-Preserving Interlaminar Decompression(MILD)for Multi-Level Lumbar Spinal Canal Stenosis Hitoshi TONOMURA, et al. [Purpose] Muscle-preserving interlaminar decompression(MILD) was developed to achieve less invasive surgery for lumbar spinal canal stenosis(LSCS). The purpose of this study is to evaluate the clinical results of MILD for multilevel LSCS. [Materials and Methods] Sixty-one patients with LSCS were retrospectively investigated. Group A consisted of 17 patients(12 men and 5 women, mean age 69.4 years) who underwent MILD for multi-level(above 3 intervertebral levels) LSCS. Group B consisted of 20 patients(12 men and 8 women, mean age 72.2 years old) who underwent MILD for 1 level LSCS. Operation time, intraoperative blood loss, recovery rate of JOA score, period for postoperative ambulation, length of stay, and complication were evaluated. [Results] The mean operation time and intraoperative blood loss were higher in Group A than Group B. The average recovery rate of JOA score was 58.7% in Group A and 66.8% in Group B. There was also no significant difference of the period for postoperative ambulation, length of stay, and complication rates. [Discussion] The clinical outcome of MILD for multi-level LSCS was satisfactorily demonstrated satisfactory. MILD could be suitable for less invasive surgery of LSCS, even if with multi-level stenosis.

Posterior Decompression for Lumbar Disorders in Patients with Long-Term Hemodialysis Takao MOTOSUNEYA, et al. We reviewed 6 hemodialysis patients with lumbar spinal canal stenosis who underwent surgery in the past 2 years. There were 6 patients(3 male, 3 female; ages 53-68, average 60.0 years, follow-up 9-24, average 18.5 months). The mean duration of hemodialysis was 20.5 years(5-30 years). All patients were treated with laminectomy or fenestration, and bone graft or spinal instrumentation was not applied. The average duration of surgery and volume of blood loss were 118 minutes and 259 ml, respectively. JOA scores were improved postoperatively from 12.5 to 23.8 points, with an average recovery rate of 71.0%. Although postoperative spondylolisthesis developed in one patient, there were no other complications during or after surgery. The result of posterior decompression surgery for lumbar spinal lesions in hemodialysis patients was favorable at least in the short term. However, we should follow them for the long term because of the possibility of canal stenosis recurrence and development of postoperative instability. When attempting spinal surgery on hemodialysis patients, we should consider not only the spinal pathology but also the general condition of the patients.

Free Papers 3: Cervical Fixation A New Technique for Posterior Cervical Spinal Fusion ―Wiring of Inter-Spinous Bone Graft Spacer between Lamina and Spinous Process Using Polyethylene Cables― Toru FUNAYAMA, et al. We developed a new operative technique for posterior cervical spine fusion using ultra high molecular weight polyethylene(UHMWPE) tapes. The subjects were three patient with fracture and dislocation of the lower cervical spine(C5/6 in two and C6/7 in one) with facet interlocking and injury of other posterior components caused by flexion and distraction force. After reduction of the facet interlocking through a posterior approach, half of the spinous process was cut off and grafted at the prepared inter-spinous space. Then sublaminar fixation was carried out between the lamina(upper spine) and spinous process(lower spine) with two UHMWPE tapes. Additionally, anterior interbody fusion was performed using autologous iliac bone. No dislocation of grafted bone or other complications were encountered. Bony fusion was obtained within three months in all cases. Several methods for posterior cervical spinal fusion had been reported. In our technique, the interspinous bone spacer acted not only as a grafted bone for fusion but also as a blocker preventing over-extension. We suggest that our technique is a useful procedure that may keep proper alignment and give sufficient stability without using metal instrumentation.

Surgical Results and Problems of Occipito-Spinal Fusion(OSF)for Rheumatoid Cervical Spine Masato TAKABATAKE, et al. OSF is regarded as a surgical procedure for rheumatoid cervical spine with irreducible AAS and VS with or without SAS. The purpose of this study was to determine the optimal fusion length of OSF for RA of the cervical spine. Thirty-nine RA patients who received OSF were followed for more than one year. Ten cases underwent"short OSF", with the caudal end of fusion from C2 to C4. Twenty-nine cases underwent"long OSF", ranging from C6 to D2. The results were evaluated according to JOA scores. Postoperatively, all cases showed improvement of the symptoms with an average recovery rate of the JOA score of 38.8%. Subsequently, 15 patients(38.5%) showed aggravation of ADL. The average recovery rate at final follow-up was 25.7%. Three cases of"short OSF"(30.0%) showed aggravation due to instability at the caudal level to the fused area. 90.9% of cases showed progressive disabilities due to the deterioration of RA during a period of more than five years. Although satisfactory results of OSF for RA were demonstrated, the aggravating factors are the progression of RA in its natural course and the instability at the caudal level of the"short OSF", which could be avoided by using"long OSF".

Posterior Fixation Using a Hook and Rod System for Atlanto-Axial Subluxation Hironobu YAMADA, et al. We performed atlanto-axial fixation using a hook and rod system for 7 patients with atlanto-axial subluxation. The causes were rheumatoid arthritis in 4 patients, idiopathic in 2 and os odontoideum in one. The average age at surgery was 55 years. The Cotrel-Dubousset(CD-M8) system was adopted. The claw mechanism was applied bilaterally between the hook of C1 posterior arch and the hook of C2 lamina. The average duration of surgery was 175 minutes and the average volume of blood loss was 206 ml. Two patients with cervical myelopathy due to spinal canal stenosis simultaneously underwent laminoplasty from C3 to C7 levels. There were no complications during surgery and no patients became worse after surgery. Solid bony union was confirmed in all patients. In conclusion, the procedure

Free Papers 4: Cervical and Thoracic Spine Initial Surgical Outcomes of K-Method Laminoplasty ―Learning Curve and Technical Problems― Masakazu YOSHIDA, et al. Initial surgical outcomes of K-method laminoplasty were studied, in particular technical progress and problems. 24 patients were operated upon by the authors between May of 2006 and August of 2008. The mean JOA score was 13.9 before surgery and 15.8 after surgery. One patient had transient C5 palsy, but none complained of severe neck pain after surgery. The average operating time was 162 minutes (94-330 min), and the average blood loss was 114 g (a little-450 g). The average length of skin incision was 4.5 cm (3-9 cm). However, after the ninth operation, these figures fell to within 160 minutes, 100 g and 5 cm respectively. We faced two technical problems. One was the displacement of either the spinous process or the spacers after surgery, which occurred in 11 cases and 2 cases respectively. The other was fracturing in the central portion of the lamina due to excessive cutting of the spinous process. Both problems appeared to be the result of unrefined surgical technique. The K-method's original instruments made it easy to do the operation with only small skin incisions. Now we will continue to aim at reconstructing posterior elements firmly and with physiological shape.

Results for Surgical Treatment of Cervical Lesions by the Open Door Laminoplasty with Spinoplastic Hydroxyapatite Spacer in Our Institutes Keiichi AKATSUKA, et al. [Purpose] Results of surgical treatment by open-door laminoplasty using a spinoplastic hydroxy apatite spacer (K-method) for patients with cervical lesions in our institutes were discussed. [Subject and method] From July 2002 to December 2007, 61 patients were treated with the K-method and clinical outcome and the neuroradiological imaging were evaluated for 52 patients followed for more than 6 months. They were 31 males and 19 females, and their ages ranged from 30 to 91 years. The mean age of these patients was 65 years. The diagnoses of these patients were as follows; cervical spondylosis 31, ossification of posterior longitudinal ligament 14, and cervical canal stenosis 5. [Results] Symptoms and neurological signs of motor weakness and clumsiness were gradually improved, but numbness remained. Post-operative spinal canal extension and sagittal alignment of the cervical spine were preserved in most of the patients. Using laminoplasty by the K-method, good clinical outcome and neuroradiological improvement of the cervical spine were achieved.

Free Papers 5: Vertebroplasty Vertebroplasty through Extrapleural Approach for Osteoporotic Compression Fractures with Intracanal Bony Protrusion Tsukasa NISHIURA, et al. Transpedicular vertebroplasty for the treatment of osteoporotic vertebral collapse in which bone fragments protrude into the spinal canal is considered to be contraindicated because of the increased risk of leakage of the material into the epidural space. For three such cases, we injected a bioactive bone substitute, calcium phosphate cement(CPC), through a small hole made in the lateral wall of the vertebral body. There was no leakage of the material and pain relief was achieved immediately after the operation. Vertebral collapse was arrested during the follow-up. The procedure of new vertebroplasty is described in this paper. Under general anesthesia the patient is placed in a lateral position. The lateral wall of the collapsed vertebra is exposed through the extrapleural approach. If the spinal cord is compressed by the protruded bone fragments, decompression before vertebroplasty is an option. A small hole is made in the lateral cortical bone of the vertebral body. The cancellous bone is curetted to make a cavity which is filled with the material. CPC is injected into the cavity through the hole. Patients are allowed to walk, or sit in a chair without wearing a girdle, after at least 3 days of bed rest.

Free Papers 6: Lumbar Spine 2 Surgical Management with Full-Scale 3D Model for Developmental High-Grade Spondylolisthsis Nobuhisa SATOH, et al. Objective: This is a case report of developmental high-grade spondylolisthesis, in which 3D a full-scale model was useful for preoperative planning and intraoperative maneuver. Case: A 12-year-old girl was referred to our institute because of her postural abnormality induced by high-grade spondylolisthesis of the L5 vertebral body. Surgical intervention was performed because of bladder dysfunction which gradually developed at the age of 11. X-ray showed high-grade spondylolisthesis(Meyerding grade 4). A huge bony formation developed at the posterior wall of L5 vertebral body, which encroached widely in the spinal canal on CT scan. To achieve decompression and reduction more safely, we produced a full-scale 3D model from CT (DICOM format) by a rapid prototyping technique. This model was useful to illustrate the contour of the bony spur or to decide the amount of bone that should be resected. PLIF was performed and olisthesis was corrected with the SOCON spinal system. Result: Bony union was completed at five months after operation. Immediately after operation, her postural abnormality improved. Conclusion: The 3D full-scale model was useful for preoperative planning and intraoperative maneuver.

Posterior Instrumentation Surgery Using Pedicle Screw System (PS) and S-Plate for Thoraco-Lumbar Spine Burst Fracture Keiji HAYAKAWA, et al. Posterior surgery using the pedicle screw system with one above one below fusion is sometimes insufficient for thoraco-lumbar burst fracture. We tried to add an S-plate to conventional pedicle screw instrumentation to reinforce the initial fixation. Four patients with two T12, one L2 and one L3 burst fractures received this surgery. The fracture type was Denis A in 1 vertebra, and B in 3. McCormack score was 8 in one vertebra, 7 in 2, and 4 in 1. Mean operation time and blood loss were 178 min and 554 ml. Preoperative kyphosis angle was changed from 19.5°to 12.5°post-operatively and to 13.1°at follow-up. Loss of correction by 3.1°occurred in the McCormack grade 8 case, but there was less than 1°loss in the other three. No patients complained of LBP. Pedicle screw fixation with S-plate is effective for a burst fracture.

 

 

 

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