Surgical Technique for Spine and Spinal Nerves
Vol.6 No.1(2004)

Main Theme 1：Extramedullary Cord Tumor
Operative Prognosis of Spinal Meningioma and Nerve Sheath Tumor
Isao Kitahara, et al.
(Purpose)Most intradural extamedullary tumors are meningiomas or nerve sheath tumors. In this study, we examined the clinical courses of patients with meningiomas and nerve sheath tumors encountered in our hospital and assessed what kind of surgery should be conducted.(Subjects and Methods)We conducted a retrospective study of the clinical characteristics and postoperative courses of 25 cases of spinal cord meningioma and 70 cases of nerve sheath tumor treated at our hospital from 1981 to December 2002.(Results)Among 27 operations for spinal cord meningioma, the surgical results were evaluated as Simpson grade I in 5 cases, grade II in 17, grade III in 2 and grade IV in 3. Recurrence was found only in one case of meningioma of the great foramen(grade II). Among 70 cases of nerve sheath tumor, complete removal was achieved in 49 cases and residual tumor remained in 21. Seven cases had multiple operations, comprising 6 cases of dumbbell tumor and 1 of intramedullary tumor. The prognosis of nerve sheath tumors was good. Only one case of recurrence was observed despite the presence of residual tumor in some cases.(Conclusion)1 In spinal cord meningiomas followed for 10 years after operation, no recurrence was observed even in cases with residual tumor at the meningioma attachment site. 2 In nerve sheath tumors, prognosis is good, with a low recurrence rate despite the presence of residual tumor in some cases. The presence or absence of NF and histopathologic grade of malignancy are probably important determinants of prognosis.
Minimally Invasive Endoscopic Surgery for Spinal Arachnoid Cysts
-A Case Report-
Yuki Tanibata, et al.
Conventional surgical treatment for arachnoid cyst calls for total resection of the cyst and the closure of the communication between the cyst and the subarachniod space. In cases of wide arachnoid cysts, these procedures are very invasive, and may bring about spinal deformity as well as instability in the future. On the other hand, there are some reports about wide arachnoid cysts suggesting that only closure of the communication would be an effective method, even if the entire cyst were not resected.
We threrfore performed a new type of minimally invasive surgical technique using an endoscope to treat a spinal arachnoid cyst.
A 58 year-old man had a spinal arachnoid cyst at the Th8-L3 level. An endoscope(1.8 mm diameter)was inserted for resection of the cyst at the L2/3 level. After identifying the communicating area, minimal laminectomy was performed and the area was closed. Postoperatively the patient felt relief. The postoperative MRI findings showed that the mass had been reduced.
The endoscopic method has brought the possibility of identification and distinction of communicating areas between the cyst and the subarachniod space. The endoscope allows minimally invasive surgery for treatment of the spinal arachnoid cyst.
Operative Results of Giant Neurogenic Tumors
Yurito Ueda, et al.
［Purpose］Giant spinal neurogenic tumors are relatively rare, and there are few reports about them. We investigated the operative results of giant neurogenic tumors that occurred in the thoraco-lumbo-sacral spine.
［Object and Method］There were 9 cases from 1991 to 2001. The mean age was 38.9 years and the mean postoperative period was 7 years 5 months. Five were males and 4 were females.
［Result］All the patients had dumbbell tumors. One was Eden type 1, 1 was type 2, 5 were type 3 and 2 were type 4. The anterior approach was selected in 2 cases, posterior approach in 4 cases and a combined anterior and posterior approach was needed in 3 cases. Spinal fusions were needed in 2 cases.
The average blood loss was 1335 ml and average operating time was 7 hours 27 minutes.
［Discussion and Conclusion］Subjective symptoms of neurogenic tumors that occur in the thoraco-lumbo-sacral spine are not always severe. In some cases they can become gigantic. In addition, their growing patterns vary, which makes the operative procedures very difficult. However, even if the size is so large, total resection is possible by using the proper approach and technique.
Clinical Experience with Primary Spinal Tumors
Mutsuhiro Tamura, et al.
Primary spinal tumors are relatively rare. We cared for two patients with primary spinal tumors.
Case 1：A 46 year-old man with a giant cell tumor(GCT)of the Th9 vertebra. The patient experienced spastic paresis.
Imaging studies showed an osteolytic lesion at the Th9 vertebra and a large mass extending from the left paravertebral muscle to the left lung field. Total en bloc spondylectomy(TES)of the Th9 vertebra was performed. Because of post-operative breakage of the rod, kyphosis had progressed, with anterior-posterior fusion(Th7-Th11).
Case 2：A 55 year-old man with periosteal chondrosarcoma at the Th2 vertebra. He presented with a gait disturbance and sensory disturbance below the level of Th6. MRI showed a mass in the posterior region of Th2/3. The patient underwent a laminectomy. The histopathological examination showed periosteal chondrosarcoma. With a view to cure, TES was performed.
These patients had favorable post-operative courses. Neither has experienced a recurrence. Treatment of primary tumors of the spine requires attention to pre-treatment evaluation, planning of the surgical strategy, and post-operative follow-up of the surgical site. Surgical removal(spondylectomy)is extremely important. Post-operative follow-up requires close surveillance for recurrence based on detailed imaging.
Main Theme 2：Intramedullary Cord Tumor
Surgical Treatment of Spinal Cord Intramedullary Hemangioblastoma
Minoru Hoshimaru, et al.
(Object)Intramedullary hemangioblastomas are relatively rare neoplasms comprising 5-11 % of spinal intramedullary tumors. The clinical characteristics of intramedullary hemangioblastomas were studied to clarify how to resect these tumors.(Patients and Methods)During the period from 1990 to 2002, a total of 18 intramedullary hemangioblastomas in 14 patients were surgically resected by either of the authors. Our series included 7 females and 7 males, ranging from 22 to 68 years of age(mean 36.4 years). Four patients were diagnosed as von Hippel-Lindau disease. Patients with von Hippel-Lindau disease had multiple tumors and were diagnosed at earlier ages(mean 25.3 years).
(Results)Seventeen tumors were exposed on the surface of the spinal cord and one was embedded in the cord. Total resection of the tumor was attempted in all cases.
However, residual tumors were recognized after surgery in two cases and were resected by re-operation. Neurological status improved in 3 cases, remained in 9 cases, and worsened in 6 cases after surgery.
(Conclusion)Sharp dissection of opaque and thickened pia mater covering the border of the tumor is crucial for minimally invasive en-bloc resection of the tumor, which may restore neurological deficit.
Preservation of the Central Vessels in Intramedullary Tumor Surgery
Kimihiko Mii, et al.
Object：In intramedullary tumor surgery, management of the central vessels is most difficult at the ventral portion of the tumor. The purpose of this study was to discuss the preservation of the central and spinal cord vessels.
Methods：The central arteries derive from the anterior spinal artery and run through the anterior median septum. They derive into the substance of the spinal cord from the top of the septum at the bottom of the anterior median fissure. Tumor arteries also derive from central arteries at this point. It is therefore necessary to coagulate tumor vessels and preserve spinal cord vessels selectively. A large tumor encroaches on the septum. Resection of this septum results in breaking of the central vessels. During operation under the ventral part of the tumor, MEP often decreases. This might suggest damage to the micro circulation of the spinal cord due to breakage of the spinal cord vessels.
Conclusion：To maintain the micro-circulation of the spinal cord, central vessels into the spinal cord should be cut selectively at the top of the septum, if possible. Exposure of the anterior pia mater during surgery might be an unfavorable prognostic sign.
The Operating Tips for the Spinal Cord Intramedullary Tumor
Koji Sato, et al.
Intramedullary spinal cord tumor is a disease which is difficult to treat. It needs a spinal cord biopsy or tumor excision, and treatment is sometimes delayed. 42 cases that we operated from 1997 to 2003 are examined. Average operating time for removal of tumor is 7.0 hours, for biopsy 4.1 hours. The average amount of extraction is 76%；postoperative evaluation is 80% excellent or good. We evaluated microscopic procedures, tumor vessels and MEP(spinal cord monitoring). Three kinds of important device, -microscope set, color ultrasonic diagnostic equipment, and spinal cord monitoring- are necessary for the operation of a spinal cord intramedullary tumor. A very important point is recognition of the posterior median fissure of the spinal cord. Preoperative angiography is unnecessary if an intraoperative color Doppler device can be used. The stabilization of intravenous anesthesia by use of the BIS(Bispectral index) monitor is useful. Two specialists who are expert in these methods think that a good result can be obtained in this way when confronted with a spinal cord intramedullary tumor operation.
Main Theme 3：Difficult Cases
Surgical Result of Down Syndrome with Atlanto-Axial Subluxation
-A Case Report that Took 8 Months to Obtain Solid Fusion-
Hozumi Narita, et al.
We report a case of Down syndrome with atlanto-axial subluxation treated by the Brooks method that took 8 months to obtain solid fusion after surgery. The patient was a 7-year-old boy. Images of radiographs showed dysplasia of atlas,axis and os odontoideum. Three months after surgery, the grafting bones were absorbed and there was no bony bridge over C1 and 2 lamina. However, we continued the procedure of Halo-vest using a nape pad. Four months after surgery, new bone formation was recognized over C1 and 2 lamina. Bone formation progressed farther 6 months after surgery, but it took two months more before complete bony fusion was obtained. Recently, the Magerl-with-Brooks method has been chosen as that which has solid fixation force. In this case, only the Brooks method using Halo-vest was used because of dysplasia of C1 and 2.
Tekmilon tape has enough strength equal to metal wire and can safely be passed under the lamina. The Brooks method with Halo-vest using a nape pad should be indicated for Down syndrome in cases of C1/2 posterior fixation, without the Magerl screw.
A Case of Pott's Disease with Psoas Abscess Controled
by Percutaneous Drainage Followed Posterior Fusion
Hiroshi Doi, et al.
We describe a case of tuberculous spinal column infection complicated by bi-lateral psoas abscess in a schizophrenic patient. The patient was a 58-year old man who had been admitted for 40 years in a psychiatric hospital. He was transferred to Tokyo Metropolitan Matsuzawa Hospital for lumbar spondylitis. He was diagnosed as Pott's disease with psoas abscess and was admitted to our department. We treated him for psoas abscess using percutaneous drainage, and followed this by posterior fixation using instrumentation. The patient was discharged without lumbago and was able to walk alone. The spine as a primary source of infection for secondary psoas abscess should always be included in the differential diagnosis.
Because the prognosis of psoas abscess can be improved by early diagnosis and prompt therapy, it needs to be considered in all patients with infection and back or hip pain.
Thoracic Paralysis Due to the Spinal Canal Stenosis Adjacently above the Apex of Severe Kyphosis of Tuberculous Spondylitis：A Case Report
Shoyo Mizutani, et al.
(Purpose)The surgical treatment of severe thoracic kyphosis due to tuberculous spondylitis is difficult. We observed a case in which the spinal cord was severely compressed at the upper thoracic level(Th4-8)above the apex(Th10) of severe kyphosis(140 degrees of angulation). We report the clinical course and surgical treatment of this patient.
(Case)A fifty-eight year old man was admitted with the complaint of difficulty in walking. He had suffered from severe thoracic kyphosis due to tuberculous spondylitis in his youth. Plain X-P, MRI and CT scan studies revealed spinal cord compression at the Th4-8 level, above the apex of kyphotic deformity. We did two staged operations. The first was anterior decompression at T4-8 by costotransversectomy, and the second was hemi-laminectomy at the affected site.
(Conclusion)The surgical outcome was favorable, with combined anterior and posterior decompression without spinal fusion.
Main Theme 4：Cervical Spine
Microendoscopic Laminotomy for Cervical Myelopathy
Shouji Yagi, et al.
Laminoplasty is a common procedure for the surgical management of cervical myelopathy. However, postoperative axial symptoms are significant problems.
We therefore developed a new technique for cervical myelopathy to overcome these problems, namely microendoscopic laminotomy using the METRx system.
The patient was placed in the prone position under general anesthesia. A tubular retractor was placed in a paramedian location 2 cm off the midline under fluoroscopic guidance. An endoscope was then anchored to the tubular retractor. After an ipsilateral laminotomy had been performed, the tubular retractor was angulated medially to resect the contralateral lamina and ligamentum flavum across the midline. Even multi-level laminotomy could be performed by wanding the tubular retractor through a single portal.
Twelve patients with cervical myelopathy underwent this procedure. They included cervical spondylotic myelopathy in 9 patients and disc herniation in 3. There were 8 patients with 1 operated disc level, 2 with 2 levels and 2 with 3. The JOA score recovery rate averaged 78%. There were no surgery-related complications. The outcomes appeared quite satisfactory.
This unilateral approach allows decompression of the dural tube, so that the contralateral soft tissues are not damaged, and the ligament complex is preserved. The short incision contributes to good cosmetic results, and reduces the invasion of paraspinal soft tissues.
Hydroxyapatite Ceramics for Multilevel Anterior Cervical Fusion
Futoshi Suetsuna, et al.
We have been using hydroxyapatite ceramics(HA)in multilevel anterior cervical fusion(AF). 37 patients with an average age of 55 years who underwent multilevel AF were evaluated clinically and radiographically. The average follow-up period was 51 months. Segmental fusion was performed in 22 patients and subtotal spondylectomy in 15. Review items in radiographic evaluation were：1. bony fusion and clear zone between HA and vertebra；2. changes of lordotic angle and height of the fused segments；3. displacement of HA；4. failure of internal fixation. All cases showed bony fusion with enough bone formation on HA without displacement of HA. Decrease of lordotic angle was observed in 4 cases, with an average of 3.0 degrees. Loss of height of the fused segments was observed in 13 cases, with an average of 2.1 mm. Recovery rate was 66.7% in myelopathy patients. Multilevel AF using iliac bone and/or fibula often produced complications. Our method for multilevel AF produced satisfactory outcomes and needed minimally invasive surgery. We conclude that there is no need to use autogenous bone in multilevel AF and that HA can replace the use of autogenous bone.
Anterior Cervical Fusion Using Interbody Cage for Cervical Kyphosis
Minoru Ikenaga, et al..
118 patients were treated with multilevel anterior corpectomy and fusion. Anterior cervical corpectomy is quite safe, less prone to complication with the graft, and effective for the treatment of cervical myelopathy.
Anterior Cervical Fusion Using Interbody Cage for Cervical Kyphosis
Yasuo Mikami, et al
In this study, anterior cervical fusion using an interbody cage was performed for treatment of cervical kyphosis, and radiological assessment was carried out to investigate the extent of prevention of deformity. The subjects of the study were 8 patients(4 males and 4 females with a mean age of 64.9 years)who underwent anterior fusion using interbody cages(SynCage-C：Nihon Matis Inc.)for kyphotic cervical vertebrae. The mean postoperative follow-up period was 10 months. Onelevel fusion was performed in 4 cases, and two-level fusion in the other 4. Laminoplasty was performed concomitantly on 7 patients. All cases achieved solid fusion within less than 3 months postoperatively, and exhibited postoperative changes to lordosis or reduced kyphosis. The local lordosis angle changed from -21 degrees preoperatively to -0.9 degrees postoperatively.
The lordosis angle for the cervical vertebrae as a whole changed from -9.6 degrees preoperatively to 8.4 degrees postoperatively.
In 3 of the 7 patients who underwent laminoplasty, the lordosis angle for the cervical vertebrae as a whole decreased even after completion of the bone union. The use of the interbody cage for anterior cervical fusion made it possible to correct the cervical kyphosis.
Spinous Process Spacer Designed for Muscle-Preserving Double-Door Laminoplasty of the Cervical Spine
Tateru Shiraishi, et al
We developed a hydroxyapatite-β tri-calcium phosphate spacer designed for TEMPL(muscle-preserving double-door laminoplasty). This new spacer(TEMPLE spacer)is fan-shaped and deeper than conventional spacers. It has two holes on each side for stitches to pass through. After expanding the spinal canal, the spacer is fixed between the two halves of the split spinous process, using two stitches, one at the tip of the split spinous process and the other at its base. Thus the two halves of the split spinous process and the spacer are tied firmly together with 4 stitches. We have applied TEMPL spacers to 28 cervical myelopathic patients. In each case, all lateral gutters created in the expanded laminae successfully united without evidence of dislocation of the spacers. In the TEMPL procedure, some split spinous processes are so thin and weak that they may easily bend or break when they are exposed to traction forces from the attaching muscles. The TEMPL spacer is made deep enough to provide a wide contact area with the split spinous process, reinforcing the two halves of the split spinous process to resist traction forces from the attaching muscles. Four separate stitches placed in 3 dimensions also provide firm fixation, preventing displacement of the spacers and allowing early postoperative neck mobilization.
Effect of a New Spacer for Cervical Alignment Correction
Shun-ichi Kihara, et al.
Objects：1)Minimally invasive technique for preservation of the posterior muscularligamentous complex. 2)This technique contributes to correction of the cervical spine alignment. 3)Not only preservation of the posterior muscularligamentous complex but also that of skin elastic function(due to about 1 inch skin incision)ensures cervical mobility and good spine alignment. The new spinoplastic hydroxyapatite spacer completes this surgical technique.
Material and Methods. Between May 2001 and January 2003, 331 patients with cervical stenotic myelopathy underwent minimally invasive open-door laminoplasty using a spinoplastic hydroxyapatite spacer, There were 193 men and 138 women, ranging from 31 to 88 years of age(mean 63 years).
Results. The JOA score increased from 6.9±3.9 preoperatively to 15.1±1.8 postoperatively. No nuerological complications were observed. Alignment of the cervical spine was improved in lordosis, straight neck and less than-8 degree kyphosis 3 months after surgery. However, alignment of the cervical spine was unchaged in cases with more than-10 degree kyphosis.
Conclusions. The new improved spinoplastic hydroxyapatite spacer has several advantages -the position of the center of gravity, the position of the hole for thread, a shape based on trapezoid theory, etc.- making a more rigid enlarged spinal canal and spinous process, and maintaining a better cervical spine alignment, covering a wider area.
Usefulness of Subaxial Transarticular Screws
Masakazu Takayasu, et al.
Although atlantoaxial transarticular screw fixation is technically demanding and carries a significant risk of vertebral artery injury, transarticular screw insertion in the subaxial cervical spine is simple and can be performed safely under lateral fluoroscopic control. It is biomechanically stronger than lateral mass screw because the screw penetrates up to four cortical layers including facet joints. This study describes the surgical technique and outcome of transarticular screw fixation in the aubaxial cervical spine. Transarticular screw insertion into the C2/3 or caudal cervical joints was performed from the articular pillar, directing it anterocaudally to penetrate the facet joint and the anterior cortex of the articular pillar, parallel to the sagittal plane. Since the vertebral artery and the nerve roots are anterior to the articular pillar at these levels, the screw can be placed safely under lateral fluoroscopic control. Twenty-seven patients ranging in age from 15 to 84 years underwent transarticular screw fixation, with a total of 91 screws. The transarticular screw was used as an anchor screw in combination with posterior cervical instrumentation in 20 patients and for facet screw fixation itself in 7 patients. Screw placement was successful and uncomplicated in all cases. The follow-up period ranged from 4 months to 6 years. No instance of screw back-out or loosening was identified radiographically, and fusion was obtained in all patients. Transarticular screw insertion in the subaxial cervical spine can be performed safely under lateral fluoroscopic control. Biomechanical strength is maintained by penetrating four cortical layers. When properly performed, this method is safe and reliable and deserves more wide-spread use.
Most Reliable Cervical Pedicle Screw Insertion Technique Using Direct Pedicle Sound after En-Bloc Laminectomy
Eiji Wada, et al.
＜Purpose＞Verification of the value of cervical pedicle screw plate fixation using direct pedicle sound technique after en-bloc laminectomy. ＜Materials & Methods＞Ten patients with instability and cervical spinal canal stenosis underwent cervical pedicle screw fixation. After en-bloc laminectomy, the location of pedicles was detected by direct sound around the pedicle with a small curved spatula through the space between the dural tube and pedicle wall. Following the entrance-hole preparation, a well designed pedicle probe was inserted into the pedicle, nosing out the inner cortex of the pedicle according to preoperative helical CT myelogram images. This technique needs neither an intraoperative x-ray image intensifier nor a complicated 3D guide machine.
＜Results＞On computed tomographic(CT)scan, there was no unexpected complete perforation and only 2/50 screws(4%)showed partial perforation(within a half of the screw diameter)to the lateral wall. There was no complication directly attributable to screw insertion. ＜Discussion and Conclusion＞US measurements after en-bloc laminectomy showed that the mean width of the dura mata had decreased from 3 to 4 millimeters. In this space, a direct sound around the pedicle was performed with a small curved spatula, and the perforated screws were found to be permissible. This technique proved its reliability, safety, and practicality.
Main Theme 5：Lumbar Spondylolisthesis
Trial Fusion by Tekmilon Tape for Lower Lumbar Instability
-Comparison with Unfixed Cases-
Yoshinori Nishi, et al.
(Purpose)We investigated the usefulness of tekmilon tape fixation instead of metal fixation in 65 patients, for the control of lower lumbar instability.
(Material and methods)We followed 50 patients for more than 3 months(32 men and 18 women, average age 67 years). All of them suffered from lumbar canal stenosis or degenerative spondylolisthesis with lumbago. We investigated the relief of lumbago and the control of segmental instability/slip on X-P between fixed and unfixed cases, comparing with the results of pedicle screw and L-rod fixation.
(Results)Whole lumbar lordosis was intermediate between that of metal fixed and unfixed cases. Local instability was as nearly controlled as in metal fixed cases. Local olisthesis was partially reduced, and reduction was maintained. Lumbago was improved in all cases.
(Discussion)Although fusion with metal fixation will ensure rigid fixation, there are some problems such as tightness of the lower back, loosening of osteoporotic vertebrae, infection, degeneration of adjacent discs, and so on. We consider tekmilon fixation as an intermediate position between metal fixation and non-fixation. The results of this study suggest that this method is less invasive and useful for the control of moderate instability and lumbago in middle-aged or elderly patients.
(Conclusion)This method is considered useful for the control of moderate instability and lumbago in middle-aged or elderly patients, instead of metal fixation.
Microsurgical Nerve Root Decompression in Patient with Spondylolysis
Yuichiro Nishijima
Purpose：The main source of radicular pain in patients with L5 spondylolysis is compression of the nerve root which passes through the lytic isthmus. The purpose of this report is to demonstrate the efficacy of microsurgical decompression technique in patients with spondylolysis who show radiculopathy. Patients：There were 17 men and 4 women with a mean age of 45.7 years. The level of spondylolysis was L5 in 20 cases and L3 in one. The mean duration of symptom was 39 months. In spite of more than 3 months of conservative treatment all patients had failed to improve. Mean preoperative JOA score was 14.8 points. Unilateral sciatica was seen in 18 patients and femoral neuralgia in one. Nerve root block was useful for establishing the diagnosis of nerve root compression at the isthmus. A wide canal sign was frequently seen in MRI. A pedicular spur and a proliferating osteocartilagenous mass were demonstrated around the lytic isthmus in lumbar CT.
Operative Methods：A 2-3 cm midline incision was enough to access the isthmus under microscopic control. By cutting the cranial edge of the floating lamina with a cutting burr, the caudal aspect of the lytic lesion of the pedicle was clearly identified.
The pedicular spur and proliferating osteocartilagenous mass were totally resected to obtain nerve root decompression.
Results：Unilateral decompression was performed in 20 cases and bilateral in one. The mean operation time was 56 minutes.
Blood loss was minimal. The mean follow-up period was 11.8 months(28-6). Preoperative JOA score of 14.8 points improved postoperatively to 24.1 on average.
Discussion and Conclusion：Invasive surgery such as the Gill operation, direct repair or spinal fusion, was formerly indicated for painful spondylolysis, but minimally invasive surgery, microsurgical decompression of the nerve root that passes beneath the lytic isthmus, is effective for the improvement of patients' symptoms.
A Strategy for Surgical Treatment of Lumbar Degenerative Spondylolisthesis
Shigeru Hirabayashi, et al.
［Purpose］To determine a strategy for surgical treatment of lumbar degenerative spondylolisthesis. ［Patients and Methods］Eighteen patients with L4 degenerative spondylolisthesis underwent decompression and spinal fusion only at the L4/L5 level using a pedicle screw system, from 1998 to 2002(13 females, 5 males, ages 46-77, average 64.6 years old, follow-up 1y-5y2m, average 2y8m). Spinal instability was defined as a difference of kyphotic angle between flexion and extension on functional X-ray view of 5 degrees or more. ［Results］In 13 patients, olisthesis was reduced, and this was followed by PLF in 10 patients and PLIF in 3. Five patients had preoperative instability. In 2 who underwent reduction and PLF, L5 pedicle screws were broken. In one patient who underwent PLF in situ and 2 who underwent reduction and PLIF, no pedicle screws were broken. In one patient without instability who underwent reduction and PLF, L5 pedicle screws were broken. There was a tendency for pain and/or numbness in the lower extremities to remain in patients who underwent reduction of olisthesis.
The ratio of bony union was 83.3%. ［Conclusion］To determine a strategy for surgical treatment of lumbar degenerative spondylolisthesis, it is important to evaluate preoperative instability at the olisthesis level. In patients with instability, olisthesis is reduced, and this is followed by PLIF. In patients without instability, olisthesis is not reduced, but PLF is preformed
Surgical Technique for Degenerative Lumbar Scoliosis with Spondylolisthesis
Naoki Asami, et al.
28 surgical cases of lumbar degenerative scoliosis(total PLIF 120 cases)between January 2001 and August 2003, followed for 4-36 months. Cobbs angle over 10 degrees(CT, plain X-P)
Mean age：71 years(range 55-87)Male 12, Female 16
Symptoms consisted of back, buttock and thigh pain with intermittent claudication in all patients.
All cases showed lateral slipping；6 had severe column rotation. All showed anterior slipping over 1 mm on lateral dynamic X-ray. Operative levels：2-level fusion 12cases, 3-level fusion 10cases, over 4-level fusion 6cases. Postoperative improvement ratio of Cobbs angle in coronal plane：mean 67%(from 28.6 to 95). S1 screwing(bicortical)was performed for 4(iliac-sacral salvage：2). L5 screwing was performed for 24(S1 screwing was added for 1 case).
Alignment correction in both coronal and sagittal planes(total spinal view)should always be considered in cases of severe scoliosis with osteoporosis.
Bicortical S1 screwing was not adequate for long fusion, even if inter-body fusion was performed. An Iliac or intra-sacral rod should be placed as a salvaging operation.
TLIF using a mesh cage and PLIF using a short-threaded cage with a view to total spinal balance can help to correct sagittal alignment.
Spinal Fusion for Degenerative Lumbar Scoliosis
Akiyoshi Yamazaki, et al
Thirty patients who had undergone spinal fusion(at more than 2 levels)for degenerative lumbar scoliosis(more than 10 degrees)were retrospectively reviewed. The average age at operation was 64 years. The average postoperative followup period was 2 years and 3 months. The average number of fusion segments was 3(2-5 levels). PLIF was carried out in 26 patients, and PLF or PSF in 4. A pedicle screw system was used in all cases. The operation time was 4 hours 53 minutes and intraoperative blood loss was 2019 g on the average. JOA score was 12.4 points preoperatively, and 24.6 points at follow-up, with a recovery rate of 73.5%. The scoliosis was 17.3 degrees preoperatively and 9.6 degrees at follow-up(p＜0.01). The lordosis was 30.7 degrees preoperatively and 29.9 degrees at follow-up. The overall fusion rate was 77%. The fusion rate for PLIF was 85% and that for PLF or PSF was 25%(p＜0.05). It also decreased remarkably as the number of fusion segments increased(100% for 2 levels, 88% for 3 and 17% for 4 or 5 levels). Additional fusion procedures were preformed for 3 patients with adjacent discopathy and 1 with non-union.
Free Papers
Foramen Magnum Decompression for Pediatric Patients with Achondroplasia
-Advantage of Using Ultrasonic Bone Scalpel in Craniectomy-
Yoshitaka Hirano, et al.
Presented are our favorable surgical results of foramen magnum decompression using an ultrasonic bone scalpel in pediatric patients with achondroplasia. The advantage of the present surgical procedure is discussed in comparison with its conventional counterpart. The study includes 4 acondroplastic children(3 males and 1 female)of 4 months to 2 years old, who were referred to the authors after magnetic resonance(MR)studies had revealed foramen magnum stenosis. Since these children under 4 years of age have an excessive risk of sudden death, surgical decompression of the craniovertebral junction is indicated to prevent their tragic loss. Using an ultrasonic bone scalpel(SONOPET UST-2001：M & M Co., Ltd), foramen magnum decompression and C1 laminectomy were performed with minimum surgical risk of dural laceration or cervical cord compression, and the shorter operating time was noted in comparison with the conventional procedure. In all 4 cases, excessive snoring, motor weakness of the upper extremities and truncal ataxia, which were considered to be symptoms caused by foramen magnum stenosis, were reduced shortly after the operation. The use of SONOPET is considered to be beneficial in minimizing the surgical invasion accompanying with foramen magnum decompression in pediatric achondroplasia patients.
Skip Laminectomy for Cervical Spondylotic Myelopathy Associated
with Athetoid Cerebral Palsy
Hideo Hosoe, et al.
The results were reviewed of 4 consecutive skip laminectomies since Nov. 2002, for cervical spondylotic myelopathy associated with athetoid cerebral palsy. All paitients were men, and their ages at the time of the operation were from 31 to 63. The 2nd case had received 1-level cervical corpectomy 15 years ago. The 3rd case fell and suffered incomplete spinal cord injury. Only the 1st case was treated by the original Shiraishi's method. In the other cases we modified themethod.
The mean operation time and the amount of bleeding were 173 minutes and 83 g respectively. The number of removed laminae was 2 in 1 case, and 3 in 3 cases. There were no cases with postoperative infection or neurological deterioration.
Many authors have recommended a circumferential cervical fusion, with or without a halo vest, in cases with severe instability and deformity of the cervicalspine, to achieve the highest rate of fusion. Skip laminectomy may be recommended for cases in which physiological lordosis is present without severe instablility. In comparison with C3-7 T-saw laminoplasty, the characteristics of this method are longer operation time, less blood loss and preservation of the paraspinal muscles.
Skip laminectomy is less invasive and is effective for cervical spondylotic myelopathy associated with athetoid cerebral palsy.
The Clinical Study of C3-C4 Level Cervical Spondylosis with Unusual Clinical Signs
Hitoshi Ikegami, et al.
We report 11 cases of cervical myelopathy diagnosed as C3-C4 disorder with special regard to the mechanism of unusual clinical signs and surgical outcome. There were 11 subjects；the surgical procedure was expansive open door laminoplasty in 10 cases and anterior cervical fusion in one. The main preoperative clinical sign was vertigo；unstable feeling(drift) was noted in the standing position and unstable walking, unaffected by opening or closing the eyes, in all cases. In addition, clumsy hands in 9 cases and numbness of glove & stocking type were reported in 8 cases. Exaggeration of reflexes was found in 7, but they were normal in 4. The finger to nose test was positive in all cases. Signs suggesting cerebellar symptoms were unusual, so that diagnosis from these signs referring to cerebellar disorder and treatment may have been late. We consider that the mechanisms of such unusual clinical signs were caused by a disorder of the propriospinal neurons in the gray matter of the cervical cord at C3 and C4 levels. It is important to treat before irreversible changes occur in the gray matter；therefore early diagnosis and treatment are also important.
Short-Term Outcome of Extensive Open-Door Laminoplasty(ELAP)
with a New Approach(Shiraishi)
Preserving the Attachment of Extensor Muscles to Spinous Process
Michihiro Kamata, et al.
To reduce axial pain after extensive open-door laminoplasty(ELAP), we performed ELAP with Shiraishi's approach(S-ELAP), which leaves the attachment of extensor muscles to the spinous process and minimize the damage to extensor musculature. In this study we include 9 patients who underwent S-ELAP, 3 men and 6 women with an average age of 72 years. The average follow-up period was 6 months, average preoperative JOA score 10.3 points, operation time 178 minutes, intraoperative bleeding 155 g, postoperative JOA score 12.7 points and improvement rate 38%. Postoperative neck pain and shoulder stiffness persisted in 5 patients(55%). Damage to soft tissue attached to the cervical spine or to bony structure, or postoperative treatment, could be the cause of postoperative axial pain. We could not reduce these symptoms by preserving the attachment of extensor muscles to the spinous processes and suturing these muscles symmetrically.
New Operative Procedure of Open Door Laminoplasty
without Making Gutter on Laminae -Preliminary Report-
Kaiji Ohta, et al.
Open door laminoplasty has been well accepted for the treatment of degenerative cervical disorders. To make this operative procedure easier and less invasive, the author developed a new technique, avoiding making a gutter with airtome on the laminae. Comparison was made between ten patients operated upon by the old method and 10 operated upon by the new method. The results indicated that less blood loss, shorter operation time, less requirement of postoperative analgesics, shorter need of postoperative brace and shorter hospital stay were observed in the new method.
Lumbar Spontaneous Epidural Hematoma Locating in Ventral Vertebral Space of L5
-Case Report-
Eiichiro Honda, et al.
A 38 year-old man presented with a one month history of right buttock pain together with radicular pain along the L5 nerve root. MRI showed a ventral extradural soft tissue mass with peripheral enhancement at the L5 vertebral level which looked like a round cystic lesion. It contained xanthochromic fluid, which was subtotally extirpated, and histological examination of the wall revealed fibrous granulation with less inflammation. Wiltse described a fibrous membrane lying between the posterior surface of the vertebral bodies and the posterior longitudinal ligament. Furthermore, the vein of Batson lies on the dorsal surface of this peridural membrane, and perforates the membrane. Gundry reported a strong coincidence between such an epidural hematoma and underlying disk disruption, based on 18 surgically confirmed cases.
We agree with Gundry's idea of a tear of the fragile epidural veins lying adjacent to the displaced annulus or nucleus but it was not obvious why this epidural hematoma had a long history and had continued to cause clinical symptoms such as these of intracranial chronic subdural hematoma.
Comparative Study between METRx-MD and MicroLove's Methods
for Lumbar Disc Herniation
Atsuomi Aiba, et al.
To determine whether the METRx-MD method is less invasive than the MicroLove method for lumbar disc herniation, we retrospectively compare two procedures with regard to blood loss, painkiller doses required on the operation day, periods to initial wheelchair riding and walking, first day/preoperative ratio of WBC, and CRP in the first week after the operation.
Material comprises 10 LDH patients who underwent the MicroLove method and 9 who underwent the METRx-MD method in our hospital. All discectomies were performed on single level via hemilateral approach. We did suction drainage for every case treated by the MicroLove method and did not use any drain for those treated by METRx-MD.
Periods to initial wheel chair riding were shorter in the METRx-MD group(1.4 days)than in the MicroLove(2.9 days). Periods to initial walking were also significantly shorter in the METRx-MD(2.0 days)than in the MicroLove group(5.0 days).
CRP at one week was significantly higher in the MicroLove(0.90±0.64)than in the METRx-MD(0.28±0.64). There were no significant differences in blood loss, painkiller doses required on first day/preoperative WBC ratio.
These results indicate that METRx-MD is less invasive than the MicroLove method, and enables patients to regain daily activity earlier.
Clinical Experience of Interspinous Process Spacer(Sten-XTM)under Local Anesthesia for Lumbar Canal Stenosis
Hisakazu Tachiiri, et al.
We recently performed operations using Sten-X(interspinous process spacer)for lumbar canal stenosis under local anesthesia. Ten patients of 72 years old on average, 8 males and 2 females, were operated with Sten-X in 2002. They were all followed for over 6 months. The average operation times using one Sten-X(6 cases)and two(4 cases)were 52 and 79 minutes respectively. The blood loss in each operation was less than 50 g. Postoperative hospitalization was 8.1 days on average. After the operation, the average lumbar lordosis angle was decreased by 2.6 degrees, posterior disc height increased by 1.4 mm, and rate of canal stenosis decreased by 12.4%. The average JOA score was 15.0 points preoperatively and 23.2 postoperatively. There were two complications(mis-insertions)and one additional operation. By using Sten-X, the stenotic lumbar segments were maintained in slight flexion, and a satisfactory clinical outcome was obtained. The usual surgery for lumbar canal stenosis is done under general anesthesia, but this method can be safely performed under local anesthesia. We
conclude that this method is a very useful new approach involving minimally invasive surgery for lumbar canal stenosis.
Laminectomy Using a Midline Spinous Process Splitting Approach in Patients with Lumbar Canal Stenosis
Taku Ogura, et al.
The object of the present study is to introduce laminectomy using a midline spinous process splitting approach to conserve the posterior parts and investigate the postoperative results.
The patient group consisted of 9 males and 13 females, ranging in age from 51 to 79 years. They were followed up for one month to 10 months after surgery.
The surgery was first performed by exposing the tip of the spinous process and dividing the spinous process from its tip to its base into two halves at the midline, using a diamond burr. Next, the base was ground to the inner table to extirpate the inner table and the ligamentum flavum with a Kerrison punch. After approaching the midline of the dura mater, the trumpetshaped vertebral arches were both excised with a single-edged gouge by tilting the surgical microscope. The separated spinous process was reconstructed with absorbent thread when sealing was done.
The number of decompressed vertebra was 3.4(mean), the surgical time for each vertebra was 61.8 minutes, and the amount of bleeding was 79.3 ml. The postoperative periods before resumption of sitting position and walk were 1.9 and 3.0 days. The postoperative improvement rate was 76.5%.
Lumbar Lesions with Rheumatoid Arthritis Treated Surgically
Yuji Matsubara, et al.
The purpose of this study was to evaluate surgical management for lumbar lesions associated with rheumatoid arthritis. There were 4 men and 9 women. The mean age at operation was 62 years(53-73). Diagnosis was spondylolisthesis in 6 cases, lumbar canal stenosis in 3, and collapse of vertebra in 4. Of 13 patients fenestrations were done in 2 cases, PLF in one, PLIF in 5 and combined anterior and posterior fusion in 5. Average operation time was 284 minutes(32-552 minutes).
The average estimated blood loss was 750 ml(5-1460 ml). Low back pain, lower extremity pain and sensory disturbance were improved in all cases. One case died of amyloidosis 3 months after surgery. Dural tear, superficial infection and pseudarthritis each occurred in one case. Narrowing of disc space, erosion of end plate, spondylolisthesis and collapse of vertebrae are seen in lumbar lesions due to RA. Because of chronic use of steroids, poor bone quality, surgical morbidity and mortality are apparently higher than in other degenerative lumbar diseases. Careful evaluation of operation methods, fusion area, and type of implants is needed for the treatment of lumbar lesions in RA.
Effect of Spinal Fusion on Fused and Adjacent Level
-Finite Element Analysis―
Chizuko Murayama, et al.
It is worth knowing preoperatively the effect of spinal fusion both on the fused and the adjacent level.
A 43-year-old woman who had recurrent L5-S lumbar disc herniation three times after previous surgery required lumbar spinal fusion. We reconstructed the preoperative CT and MR images of her lumbar spine and completed a tailor-made threedimensional finite element model.
We have performed finite element analysis for some types of lumbar spinal fusion. The result suggests that the loss in spinal mobility and shock absorption at the fused L5-S level would be compensated at the adjacent L4-5 level. This means that the more the spinal fusion is rigid, the more degeneration will be accelerated at adjacent motion segments. It is also clear that an interbody spacer brings about not only a remarkably large stress at the fused level but also a significantly large strain at the adjacent level. We may conclude that a kind of‘rather soft fusion'will benefit the system in the long-term prospect. Thus we decided in this case to do L5-S spinal fusion without any interbody spacers but with posterior/posterolateral bone grafting and instrumentation.
The Effects of Multi-Level PLIF on the Adjacent Segment Degeneration
Kazuto Miura, et al.
【Purpose】To evaluate the relation between upper adjacent segment degeneration after multi-level PLIF and sagittal alignment.
【Materials & Methods】Twenty-five patients who underwent multi-level PLIF with follow-up periods of 24 months or more after surgery were included. All patients were treated with cylindrical interbody cages and pedicle screw system. The average age at surgery was 64 years. The mean follow-up period was 37 months. The upper adjacent intervertebral disc height was measured to assess the degree of disc degeneration. Moreover, the patients were divided into a group in which the lordosis angle of the fused segment increased, and a group in which it decreased. Changes of disc height and lordosis angle were also measured.
【Results】There was no significant difference between the preoperative, postoperative and final lordosis angles of L1-5 and those of the fused levels. A significant narrowing of the disc height of the upper adjacent level was seen, and the decreased lordosis of the fused segments accelerated the adjacent disc degeneration.
【Discussion & Conclusion】There was an obvious relation at 3 years post-operation between the postoperative sagittal alignment of the fused segments and degeneration of the upper adjacent segment.
Modified Method of Cyst-Arachnoid Shunt for Symptomatic Sacral Cyst
：A Case Report
Yohichi Aota, et al.
A cyst-arachnoid shunt was recently developed by Morio et al.(Spine 26. 2001)as a treatment of symptomatic Tarlov cysts. The original technique consisted of insertion of a shunt tube via the check-valve aperture. We performed a modified Morio's shunt for a Tarlov cyst in a 23-year-old man who had right-sided sciatica and difficulty with bladder control. The exploration revealed that the cyst was 2.5 cm in diameter and originated from the right S3 nerve root. The check-valve aperture was assessed by gentle probing under a microscope and found to be too thin to insert a shunt tube. Therefore the shunt tube(1.4 mm in outer diameter；Create Medic, Yokohama, Japan)was placed outside the aperture and fixed to the dura and the cyst wall with a 6-0 nylon suture. Watertight closure was carried out. Although magnetic resonance images taken 1 year after surgery did not show a decrease in the size of the cyst, the patient experienced substantial resolution of his symptoms in the 1.5 years after surgery. The advantages of our modification are the prevention of nerve root injury during insertion of the tube into the check-valve aperture and to use a thicker tube than that used in the original technique.
The Currarino Triad：Report of Three Cases
Seijiro Taniura, et al.
The Currarino triad is a congenital syndrome consisting of an anorectal malformation, a sacral bone defect and a presacral mass. This condition is often noticed because of symptoms related to the presacral mass. In the literature, association of this syndrome with a tethered cord is more common than generally reported. In this paper, we describe three cases and focus on this point.