Surgical Technique for Spine and Spinal Nerves
Vol.10 No.1(2008)

Main Theme 1: Minimally Invasive Spinal Surgery(Cervical Spine)
Surgical Procedures of the Bifid Cervical Laminoplasty Preserving the Spinoligamentous Complex with Diamond T-Saw by 4cm Skin Incision
Koki ANABUKI
Kihara reported minimally invasive cervical laminoplasty by a 3 cm skin incision-style open door laminoplasty. I think that I can operate by a small incision in bifid cervical laminoplasty, preserving the spinoligamentous complex with a diamond T-saw by a 4 cm skin incision. The purpose of this study is to report about the required manual skill and short-term results. Furthermore, we add our comments on the usefulness of an electrosurgical unit knife. I examined 27 cases from June, 2006 to March, 2007. In the postoperative JOA score, good improvement was obtained. One patient had transient postoperative C5 paralysis. Postoperative pain was slight, early ambulation was possible, and it was thought that this was by an effective operation method using a smaller skin incision than the traditional procedure.
Our Newly Developed Minimally Invasive Cervical Laminoplasty(K-Method)
―Clinical Results, Improvement of Alignment―
Takeshi UMEBAYASHI, et al.
The authors developed and performed a minimally invasive cervical laminoplasty(K-method) in more than 1000 cases, and retrospectively determined the prevalence of alignment after this K-method.(open-door expansive laminoplasty with hydroxyapatite implants.)
Methods　Postoperative cervical alignment was investigated in 622 patients who underwent K-method between January 2000 and December 2006 in our hospital. The patients who were followed up for more than 12 months included 369 men and 253 women, and their average age was 61.5 years.
JOA score was used to evaluate the surgical outcome, and the C2-C7 angle, determined by tangential lines on the posterior edge of the C2 and C7 bodies, was measured on lateral radiographs in the neural position.
Results The 622 patients consisted of 49 cases of Kyphosis, 121 Straight, 409 of Lordosis and 43 of Swan-neck.
The median JOA score was 13±2.2(range: 1.5～17) before surgery and 16.5±0.9(range: 6～17), after, and the median C2-C7 angle was 9.7±9.7°( range: -27.5°～42.4°) before surgery and 14.9±9.8°( range: -33.6°～46.9°) after surgery.
In conclusion, the K-method technique tended to improve postoperative cervical alignment. According to the above description, we believe that the following are important considerations to improve postoperative alignment:(1) preservation and reconstruction of the posterior ligamentous complex,(2) the shape of our original spacer,(3) a strong hinge gutter and strong fixation between the spacer, the spinous process, and the laminae.
Development of Vertebroplasty Needles
Toru KOIZUMI, et al.
Percutaneous vertebroplasty is a very effective procedure for compression vertebral fractures. Materials for vertebroplasty(cement, needle, etc) are available as a ready-made article. We developed new needles only for vertebroplasty, which have a large inner space as compared with the conventional needles. We made 13G, 14G and 15G size needles. Our needles have almost the same size of inner space as that of one or two size bigger needles. We think that our new developed needles have a big inner space as compared with the conventional needles, and are suitable for use for vertebroplasty, which requires bone cement with high viscosity. We think that by using small size needles, vertebroplasty will be a safer procedure.
Non-Penetrating Titanium Clip for Microsurgical Dural Closure of Spinal Surgery
Naoki ASAMI
The author presents the technical procedures and benefits of non-penetration titanium clips for dural closure in spinal surgery.
20 surgical cases(Intradural extramedullary tumor 5, intramedullary tumor 2, lumbar disc herniation 3, anterior cervical fusion 2, posterior lumbar fusion 8) Ages 42-81; in Male 10, female 10.
The LeMaitre AnastoClipTM VCS was very useful and quick for microscopic dural closure because it causes no holes or tears of the dura, unlike conventional needle sutures. It took a few minutes for closure(conventional suture: 10 minutes to 2 hours). There is less risk of injuries of nerve roots than with needle suture technique. The clips are compatible with computed tomography or magnetic resonance imaging.
Clinical Trial of Disc Space Fitted Distraction Device(DFDD)for Anterior Cervical Fusion
Satoshi TANI, et al.
Purpose: The authors recently developed a new device, the disc space fitted distraction device(DFDD)(Kisco DIR). Preliminary clinical results are discussed.
Methods: Since July 2006, DFDD has been prospectively implanted during ACDF. Twenty-five patients(28 levels) were included in this study.
Results: Improvement in spine curvature was observed in 10 patients. Mean curvature index improved from －2.4 to ＋4.2. Mean C2-C7 curvature improved from ＋6.2 to ＋12.8 degrees. Mean disc angle improved from 1.1 to 6.7 degrees. Anterior disc height improved from 3.1 to 8.7 mm. Range of motion in C2 to C7 decreased by 1.5 degrees. Apparent sinking of DFDD was not observed. Solid bone fusion was certified in 17 levels out of 21 at 3 months post op.
Discussion: DFDD, easily inserted in the disc space concerned, can achieve gentle distraction of up to 8 degrees. Because of minimum sinking into the vertebral endoplate, corrected spine curvature seemed to be well maintained. Appropriate spine curvature may play an important role in prevention of progressive adjacent disc degeneration.
Conclusions: DFDD seems to have advantages such as some distraction action and less sinking process resulting in maintaining sufficient spine curvature.
Anterolateral Foraminotomy of the Cervical Spine through Split Longus Colli Muscle
Tsukasa NISHIURA, et al.
Anterolateral partial vertebrectomy of the cervical spine, a new operative technique which involves drilling into the anterolateral part of the vertebral bodies, enables radical resection of the lesion, without any fusion. The authors describe a less invasive technique in which the vertebral bodies are drilled through split longus colli muscle.
The longus colli muscles are exposed through the routine anteromedial approach. The ipsilateral longus colli muscle is split to expose the lateral wall of the vertebral bodies. The drilling is started within the dissected area of the longus colli muscle. The drilling can be extended obliquely toward the opposite side. The extruded discs or the ossified part of the posterior longitudinal ligament are resected and the vertebral canal is opened widely. Postoperatively, all patients are asked to wear a soft collar for 2 weeks.
By this technique, the vertebral bodies can be approached more laterally. As a result, the anterior edge of the vertebral bodies and the longitudinal ligament are not injured, and more than half of the vertebral bodies is preserved. There are no complaints of throat discomfort because there is little or no retraction of the esophagus and trachea.
Posterior Foraminotomy for Cervical Radiculopathy
Akiyoshi YAMAZAKI, et al.
The usefulness and invasiveness of posterior foraminotomy for cervical radiculopathy were investigated. Fifty-six patients(67 levels) were included. Nineteen patients(21 levels) underwent the operation with the surgeons' naked eyes, 18(23 levels) with the microscope and 19(23 levels) with the endoscope. The causes of radiculopathy were stenosis in 43 levels　and disc herniation in 24 levels. The operation time was not significantly different among the 3 groups. However, the bleeding volume was significantly increased in the naked eye surgery. As complications, transient C5 motor weakness(naked eye) and a pin hole dural tear(endoscope) were seen, each in 1 patient. The neurological recovery(sensory and motor) was not significantly different between the 3 groups. The postop. CRP, the frequency of postop. analgesics use and the postop. hospital stay were significantly reduced by using the endoscope. The % preservation of facet joints(average 70%) was not significantly different between the 3 groups. The advantages of this procedure are its lower invasiveness, the ability to see the nerve root directly, and no need of fusion. Hemostasis is not so difficult. Foraminotomy is a safe, effective and less invasive procedure. Moreover, the endoscope is very helpful in minimizing the invasiveness in this procedure.
Main Theme 1: Minimally Invasive Spinal Surgery(Lumbar and the Others)
The Damage to the Paraspinal Muscles Followed by Posterior Decompression Surgery of Lumbar Spine
Tetsuya NAKATANI, et al.
The purpose of this study is to clarify the effect of stripping paraspinal muscles(PSM) from spinous processes(SP) in decompression surgery for lumbar spinal canal stenosis(LSCS). On surgical exposure, after unilateral limited stripping of PSM from SP followed by osteotomy of SP, the detached PSM and the severed SP with the opposite PSM behind were retracted. Pre- and post-operative MRI of 24 LSCS cases(eighteen males, six females, average 66.8 years old) who underwent partial laminectomies at 52 disc levels through the procedure described were analyzed. The ratio of cross-sectional area of the detached PSM to that of the undetached PSM was reduced from 1.03 to 0.95 postoperatively(p＜0.05), which indicated atrophic changes in the detached PSM. Furthermore, changes in high signal intensity on T2-weighted MRI were observed in the detached PSM at 34 of 52 disc levels(65.4%), whereas the same changes were observed in the undetached PSM only at fourteen disc levels(26.9%), which indicated more damage to the detached PSM. According to these results we propose the posterior approach without detachment of PSM from PS for their preservation.
Selection of the Retractor in Microscopic Spinal Nerve Decompression for Minimally Invasive Surgery
Masaharu NABETA, et al.
The authors tried to clarify what kind of retractor was suitable in microscopic spinal nerve decompression for minimally invasive surgery.
Materials and Methods: Two hundred and four patients were treated with one of 4 retractors, Caper, METRx, Quadrant and Trimline between April 2005 and April 2007. 78 cases of lumbar disc herniation(LDH) were treated by microdisectomy. 92 cases of lumbar canal stenosis(LCS) were treated by bilateral fenestration through unilateral approach. 35 cases of lumbar radiculopathy(LR) were treated by microlumbar foraminotomy. 16 cases of cervical radiculopathy(CR) were treated by microcervical foraminotomy.
Results and Discussion: Casper was selected in 2 cases of LDH, 31 of LCS, and 6 of LR. METRx was used in 68 cases of LDH, 17 of LCS, 5 of LR, and 16 of CR. Quadrant was used in 4 cases of LDH, and 44 of LCS. Trimline was used in 28 cases of LD.
The authors recommend METRx for patients with LDH and CR. Quadrant is recommended for LCS because of its wide view of the operation field and suitability for fenestration of the contralateral side from the approach side. Trimline is recommended for CR because of its suitability for the gap between facet joint and transverse process. Casper is recommended for obesity or multilevel bilateral fenestration through unilateral approach.
An Axle Weight Test on Sinking of Interbody Fusion Cages in Lumbar Spine Fusion Procedures
Shunsuke IKUMI, et al.
From the viewpoint of the weight loaded to the axle alone, 1) the weights loaded to the axle when 2 cages were fixed and when a single cage was fixed and 2) the degrees of sinking of a threaded cylindrical cage and a box type cage were compared in this study, respectively. Three types of cages of TLBC, HMA, and TERAMON were used. In each type of cages, 2 cages were inserted into the porcine spinal interbody from a frontal direction and one cage from an oblique direction, respectively, and 30 kg weight was loaded to the FSU including a pair of upper and lower vertebral bodies. The weight and sinking were measured from the lateral roentgenogram. In all types of cages, the degree of sinking was suggested less when 2 cages were inserted from the front. In comparison of TLBC and HMA which are similar types of threaded cylindrical cages, sinking of TLBC was less, perhaps due to the effect of a load bearing pillar. When one cage was inserted from an oblique direction, sinking of TERAMON was the least, and load bearing ability was superior in a box type cage.
The Management of Operative Complications in Muscle-Preserving Interlaminar
Decompression(MILD) for Lumbar Spinal Canal Stenosis
Naoki OKUBO, et al.
We report the clinical results of muscle-preserving interlaminar decompression(MILD) which we developed as a minimally invasive surgery for lumbar spinal canal stenosis(LSCS). The purpose of this study is to investigate operative complications in MILD, and to describe their management.
The subjects were 141 patients(83 males and 58 females) with LSCS who underwent MILD. Dural tear occurred in eight patients(5.7%) during MILD, but this was properly repaired without changing the surgical approach. Three patients(2.1%) had neurological deterioration caused by postoperative epidural hematoma. Although the symptoms spontaneously subsided in two patients, one had to undergo an additional operation 11 days after first surgery. No other complication occurred.
The operation in a limited operative field often leads to complications such as dural tear or postoperative epidural hematoma caused by insufficient hemostasis, and this is true for MILD. To avoid these complications, it is essential to keep the operative field clearly in view if a clear view of the operative field is not obtained, it is necessary to change the inclination of the operative
table and the direction of the surgical microscope, and to add sufficient bone resection towards the cranial, caudal, and lateral sides of the laminae.
Microendoscopic Decompression for the Affected Nerve Root in Spondylolysis Using Navigation Assistance
Yukihiro NAKAGAWA, et al.
Introduction: Direct microendoscopic decompression of the affected nerve root in spondylolysis is ideal. However, direct approach to the nerve root under microendoscopy is difficult.
Purpose: We introduce navigation-assisted microendoscopic surgery for decompression of the nerve root in spondylolysis.
Materials and methods: Seven cases of spondylolysis underwent microendoscopic surgery to decompress the affected nerve root. We directly identified the nerve root under navigation guidance, then decompressed it without necessity of laminotomy.
JOA score, incidence of disorientation throughout the surgery, and complications were evaluated.
Result: All cases were performed successfully. JOA score improved from 16 to 21. Blood loss was 64 ml. No disorientation occurred in this series.
Discussion: To minimize tissue trauma and operative procedure, laminotomy to identify the affected nerve root should be eliminated. Although direct approach to the nerve root in spondylolysis is difficult, navigation assistance resolved the issue of disorientation in microendoscopic surgery, and we did not have to perform laminotomy to identify the nerve root.
Conclusion: The navigation system provides useful information to perform microendoscopic surgery without disorientation. The combination of the navigation system and microendoscopic surgery has the potential to extend its use for various pathologies.
An Evaluation of Post-Operative Outcomes of the Surgical Treatment for Adult Lumbar Spondylolysis
Futoshi SUETSUNA, et al.
Purpose: The purpose is to evaluate the radiographic and clinical outcome of facet screw fixation without spinal fusion for adult lumbar spondylolysis.
Materials and Methods: We retrospectively reviewed the radiographic and clinical outcomes of 8 patients who underwent facet screw fixation for L5 lumbar spondylolysis. There were 5 males and 3 females, with an average age of 44.4 years. The average follow-up period was 31 months. Radiographic parameters included post-operative appearance of spondylolisthesis and breakage of screw. Clinical parameters included recovery rate using JOA score, operation time, blood loss and complications.
Results: There was no appearance or deterioration of spondylolisthesis after surgery. No case showed breakage of screws. The average pre and post-operative JOA scores were 13.3 points and 27.4 points. Recovery rate was 89.8%. The average pre and post-operative JOA lumbar pain scores were 1.7 points and 2.9 points. Recovery rate was 92.3%. The average operation time and blood loss were 104 minutes and 71.1 ml respectively.
Conclusion: Our surgical method that does not require lumbar spinal fusion for adult lumbar spondylolysis is less invasive and showed a satisfactory clinical outcome. Our method will be an option in the surgical treatment of adult lumbar spondylolysis.
Less Invasive TLIF with SEXTANT
Keisuke NAKANO
Sixty patients have been treated by less invasive TLIF with the use of SEXTANT PS system and tubular retractors. The initial skin incision was made 40 mm lateral from the midline with a length of 30 mm. The tubular retractor was placed just above the facet joint complex. After total facettectomy, the intervertebral disc was removed from the triangle space and an interbody cage was inserted. After the case placement, the tubular retractor was removed and SEXTANT PS applied. The post-operative MRI were taken at 3 and 12 months after surgery. The coronal STIR image was used for the evaluation of the iatrogenic muscle damage. The MRI findings were compared between less invasive TLIF and open PLIF.
The clinical results were satisfactory. The MRI findings showed that muscle damage was reduced in less invasive TLIF than open PLIF.
Comparison of Implants for Percutaneous Spine Fixation
Koji SATO, et al.
[Purpose] Implants for which we could insert a pedicle screw and a rod percutaneously are available for use in Japan. We found an opportunity to use three systems of SEXTANT, Xia precision, PathFinder. We compare the implant which can be used for less invasive lumbar spine intervertebral fixation(following MIS-PLIF) and review it.
[Subject] We did MIS-PLIF in 152 cases for LSCS since 2003. Of these, 100 cases in which we used both pedicle screws(following PS) include SEXTANT 94 cases, XIA 4 cases, and PathFinder 2 cases.
[Methods] We decompress by unilateral approach. For the group of SEXTANT, we use M8CD-HORIZON Pedicle Screw(following PS) and pre-bend rod using Telamon-MIS through an X-tube. For the group of Xia-MIS, we use Xia precision＋Kobashi system PS and a straight rod and OIC through LUXOR. For PathFinder, we use PS and rod, and a Fidji cage through an Xtube.
[Results] Among 20 examples of the SEXTANT group, average operation time was 92.1 min, bleeding 76.8 g; among the XIA-MIS group, 113.5 min, 77.5 g; Among the PathFinder group, 84 min, 70 g. There were no differences.
[Conclusion] It is important that we know and use each characteristic, the directions for use, and other matters that require attention.
Main Theme 2: Surgery for Craniocervical Junction
Two Cases of Craniocervical Junction Mass Lesions Treated by Postero-Lateral Transdural Approach
Takayasu IWAKOSHI, et al.
We report two cases of craniocervical junction mass lesions treated by postero-lateral transdural approach. The first case was a 69-year-old male who had received two operations previously; one was a C1 laminectomy and C3-C6 laminoplasty for cervical myelopathy due to a retro-odontoid mass and cervical spondylosis, and the other was a ganglion cyst in the high cervical portion. Two years after the last operation he presented with symptoms of neck pain and muscular weakness of right upper and lower extremities. Cervical MRIs revealed the growth of a retro-odontoid mass without recurrence of the ganglion cyst, which severely compressed the spinal cord. The second case was a 70-year-old female who presented with sensory disturbance in the left arm and leg. The MRIs of the cervical spine revealed an extradural mass located posteriorly to the dens. The lesions in both cases were removed by postero-lateral transdural approach, and then the symptoms were resolved. The first case also required occipitocervical fixation. We thought that the transdural removal of a craniocervical junction mass lesion is more useful than other surgical procedures.
Occipito-Cervical／Thoracic Fusion for Disorders in Craniovertebral Junction
Akihisa YAMASHITA, et al.
　[Objective] The purpose of this study was to evaluate the clinical and radiological outcomes and surgical problems in occipito-cervical/thoracic fusion(O-C/T fusion).
[Subjects and Methods] Eight patients were treated with O-C/T fusion from February 1988. There were 2 men and 6 women, whose average age at surgery was 57.8 years. Three cases were rheumatoid arthritis, 2 were athetoid cerebral pulsy, 2 were os odontoideum, and one was metastatic spinal tumor. Ransford wire loop for O-C3 fixation, Olerud, RRS loop, and VERTEX systems for O-C/T long fusion were used for spinal instrumentation. Ranawat's clinical results and radiological parameters were evaluated retrospectively.
[Results] Pain and neural deficits were improved in six patients. No loss of correction or postoperative kyphosis was seen. Solid bony fusion was confirmed in all cases. The average duration of surgery was 289 minutes, and the average volume of blood loss was 167.5 ml.
[Discussion] Vrious instrumentation systems have been developed, but recently we have preferred the occipital plate and cervical screw and rod systems. Design of the occipital plate, sufficient space for bone graft in the craniocervical junction, screw variation, and easier technique for connection were important factors for this selection.
A Novel C1 Lateral Mass Screw Insertion Technique in Posterior C1-2 Fixation
Nobuyuki SHIMOKAWA, et al.
〔Purpose〕To report our experience of C1 lateral mass screw insertion technique in posterior upper cervical fixation.
〔Materials and Methods〕14 patients underwent this procedure since March 2004. The disorders were odontoid fracture in 5 patients, AAS due to RA in 4, os odontoideum in 2, and other causes in 3. C1 lateral mass screws were placed using the technique described by Harms. Prior to screw placement, the entry hole of the screw was positioned 6-7 mm laterally to the lateral margin of the common dural tube. The trajectory of the screw insertion was decided according to a vertical wire line hung from the ceiling. The screw hole was drilled with a 2 mm diamond bar to the depth of 18 mm under fluoroscopy, and 3.5 mm polyaxial screws were inserted in the lateral mass directly or via the posterior arch of the atlas after tapping. The C1 and C2 screws were connected with the rods, and iliac bone grafting was done.
〔Results〕All C1 screws were placed without incident, and no neurological or vascular complications were encountered.
〔Conclusion〕Our technique of C1 lateral mass screw insertion is usefull for posterior upper cervical fixation.
Clinical Results of the Total Cervical Fusion Accompanied with Expansive Laminoplasty for RA Patients with Upper Cervical Instability and Subaxial Involvements
Hiroshi TAKEI, et al.
Upper cervical fusion for uncontrolled RA patients tends to aggravate subaxial cervical involvement(SCI). To prevent such complications, we have performed expansive laminoplasty followed by facet fusion with iliac bone in addition to upper cervical fusion for MES- and MUD-type RA patients who developed SCI with upper cervical instability.
Twelve consecutive patients with average age 66.7 years and 17 years of RA history were involved in the study. Eight OC2 and four C1-C2 instrumented fusions were performed for the upper cervical instabilitiy. For the subaxial cervical involvement, 9 French door and 3 open door laminoplasties followed by facet fusion with iliac bone graft were performed.
Fusion rate was 91.7% both in the upper cervical and the subaxial region. No instability remained or developed in any ofthe patients at 29.3 months in average after surgery.
Main Theme 3: Surgical Treatment for Spinal and Spinal Cord Tumors
Postero-Lateral Approach to the Anterior of Upper Cervical Cord
―Surgical Removal of Part of the Chordoma Extending into the Spinal Canal before Carbon Ion Radiotherapy―
Yoshinori SHIMAMOTO, et al.
Clinical trials of carbon ion radiotherapy for malignant tumors were performed between 1994 and 2003 at the National Institute of Radiological Science. The results of these trials were favorable even for radio-resistant tumors, so that carbon ion radiotherapy has been applied to chordomas arising from the cervical spine since 2004.
The carbon ion beam is superior to dose distribution, allowing selective irradiation which can reduce irradiation of the surrounding normal tissues, but in cases of patients with cervical chordomas compressing the spinal cord anteriorly, radiation myelopathy might occur. Therefore, the part of the chordoma extending into the spinal canal should be removed. This partial removal of the chordoma in the axis was done to four patients.
Two of them were operated on through a posterior approach, but the other two patients required a postero-lateral approach, because the tumors were anterior to the spinal cord. Carbon ion radiotherapy was given 4 days a week for a period of 4 weeks, and the total dose was 60.8 GyE.
A year later the tumor size had decreased, and radiation myelopathy did not occur in any case. Carbon ion radiotherapy could be a promising alternative to invasive surgery as a treatment for chordoma in the axis.
The Validity and Indication of Less Invasive Surgery Using METRx MD Tubular Retractor System for Spinal Cord and Cauda Equina Tumor
Macondo MOCHIZUKI, et al.
We have carried out the extirpation of spinal cord and cauda equina tumors using the METRx MD tubular retractor system since Aug. 2001. The objective of this study is to discuss the validity and indications of this method based on the clinical outcome of this current series. Thirty cases, including meningioma in 8(Group M), cauda equina tumor in 15(Group C), intrathecal extramedullary neurinoma in 4(Group N) and dumb-bell tumor in 3(Group D), were studied with 35 months F/U periods on an average. Mean OR times were 195 min. in group M, 171 min. in group C, 260 min. in group N and 424 min. in group D. We could extirpate tumors completely, except the dural portion of meningioma. Blood loss was little except in dumb-bell tumor. All cases showed neurological improvement with few perioperative complications. Mean length of hospital stay was 11 days in group M, 5 days in group C, 9 days in group N and 7 days in group D. No tumor recurrence was found on MRI at final F/U. We concluded that this surgery is a valid method of less invasive surgery for the extirpation of spinal cord tumor.
Neurological Recovery after Resection of Tumor Origin in Surgery of Spinal Nerve Sheath Tumors
Toshihiro TAKAMI, et al.
OBJECTIVE: Resection of tumor origin in spinal nerve sheath tumors(SNST) does not always result in significant neurological deficit after surgery. Surgical outcome of our recent experience was analyzed retrospectively to better understand the nature of SNST.
PATIENTS AND METHODS: The patient record included a total of 24 patients with SNST(12 male and 12 female), who underwent surgery over the past four years. The age of the patients ranged from 19 to 84 years. The tumors were classified into 14 in cervical, 4 in thoracic and 6 in lumbar region.
RESULTS: Microsurgical total resection with sacrifice of tumor origin was accomplished in 19 of 24 cases. No patient suffered from significant neurological deficit after surgery. Although 2 patients with subpial invasion, 2 with multiple tumors associated with neurofibromatosis type 2 and 1 of high age with recurrent tumor showed slow neurological recovery, the remaining
19 patients demonstrated satisfactory neurological recovery.
CONCLUSION: Satisfactory surgical outcome may be explained by functional compensation by the adjacent non-affected spinal levels with slow progression of the tumor itself. Resection of tumor origin in SNST may be justified to avoid tumor recurrence, although anatomical variation in each case should be carefully considered.
Problems in Surgical Treatment of Spinal Intradural Extramedullary Tumors
Minoru HOSHIMARU, et al.
(Purpose) Neurological recovery is possible after meticulous resection of intradural extramedullary tumors. However, there are several surgical pitfalls, which worsen the surgical results. For this report, a retrospective study was conducted.
(Clinical Materials) During the period from October 1998 to December 2007, 55 patients with an extramedullary tumor(35 males and 20 females, ranging from 19 to 86 years of age) were treated surgically. Our series included neurinomas(40 cases), meningiomas(12 cases), germinomas(1 case), an epidermoid, and a neurenteric cyst.
(Results) Tumors were totally resected in all of 55 patients. Detachment of the tumor from the spinal cord was easy in 53 patients, but difficult due to adhesion after hemorrhage in one patient and due to subpial extension of a neurinoma in one patient. Six tumors(2 neurinomas and 4 meningiomas) were located ventral to the dentate ligament and were resected safely through the posterior approach. The cut of the spinal nerve from which the neurinoma had originated, which was performed in all 40 cases of neurinomas, resulted in transient neurogenic bladder in 2 patients. Remarkable CSF leakage occurred in 6 patients after surgery and surgical repair was required for 2 patients.
(Discussion) Although resection of spinal extramedullary tumors is not difficult, measures to deal with such problems as adhesion to the spinal cord, symptoms due to resection of the spinal nerve, and CSF leakage should be considered.
Lumbar Intraspinal Extradural Cyst ―A Histopathological Studies―
Yuichiro NISHIJIMA
Purpose: The purpose of this report is to describe histopathological studies on lumbar intraspinal epidural cysts.
Material and methods: We operated on 32 lumbar intraspinal cysts under the surgical microscope. The cysts presented as T2 high intensity signal in preoperative MRI studies. They were located mainly in L4-5. According to surgical microscopic findings, they were classified into 3 groups: 12 juxtafacet cysts, 16 intraligamentous cysts, and 2 ganglion cysts. The specimens were histopathologically studied by H-E staining.
Results: Eight cases of 12 juxtafacet cysts showed chronic inflammatory granulation including phagocytosis, patchy hemorrhages and foam cell proliferation. Synovial linings were identified in 3 specimens. Ten cases of 16 intraligamentous cysts
showed chronic inflammatory tissue like the juxtafacet cysts. The two ganglion cysts, one originating from the surface of the disc, the other from the inner surface of the ligamentum flavum, showed chronic granulation. The granulation was seen inside the cyst cavities as well as in the cyst wall.
Conclusions: The most characteristic histological finding in intraspinal epidural cysts was chronic inflammatory granulation. A few cases showed a synovial lining. Hemorrhage due to microtrauma in the epidural connective tissue was suggested as a pathophysiological mechanism of lumbar intraspinal epidural cysts.
Free Papers
A Case of Tetraplegia after Surgery for Cervical Discitis with Kyphosis
Hitoshi HASHIMOTO, et al.
We experienced a case of cervical discitis(C3/4) with marked kyphosis. We put the patient in a halo-vest under gentle traction. After that, his neck pain and hand numbness became better. We then performed posterior fusion with pedicle　screws and lateral mass screws(VERTEX-MAX, SOFAMOR DANECK), and anterior decompression and fusion using iliac bone. However, just after the operation, we found him to be almost completely tetraplegie. Immediately we did a CT scan, and found canal stenosis. On the same day we performed laminectomy. Then, day by day, he recovered. After 4 weeks he could transfer to a wheel chair by himself, and after 8 weeks he could walk and do anything just as before the operation.
We learned that there is a risk of causing tetraplegie in patients with marked cervical kyphosis when we transfer them from the prone to the supine position, or when we correct the neck deformity by instrumentation. We should have used a Strykerframe and spinal cord monitoring. We also found it important that correction must be performed after posterior decompression.
Settling of Fibula Strut Grafts and Changes of Implants Following Anterior Cervical Corpectomy
―A Radiographic Evaluation―
Hideo HOSOE, et al.
Study design: This is a retrospective study of the settling of fibula strut grafts and changes in three types of implants used for anterior cervical reconstruction.
OBJECTIVE: To measure the settling and kyphotic angulation of fibula strut graft reconstruction for one- and two-level cervical corpectomy procedures and clarify the characteristics of each type of implant.
METHODS: Thirty-nine patients having had nonvascularized autogenous fibula strut grafting with instrumentation following a one- or two-level corpectomy were studied. We used three types of anterior cervical plate, fix type, variable type and dynamic type. Baseline radiographic measurements of height and angulation on postoperative radiographs before hospital discharge were compared with measurements performed at least 1 year after surgery.
RESULTS: The average settling manifested by loss of height across the fused segments was 2.8 mm in the fix type, 5.5 mm in the variable type and 7.8 mm in the dynamic type. The average changes in angulation were 0.8 degree in the fix type, 1.2 degrees in the variable type and 3.5 degrees in the dynamic type.
CONCLUSION: Settling of autogenous fibula strut grafting with instrumentation differed among the three types of implants. We may have to use a suitable type of implant for different pathologies.
Surgical Treatment for Retroodontoid Pseudotumor
―2 Cases Report―
Keishi TSUNODA, et al.
　【 Purpose】Myelopathy due to retroodontoid pseudotumor has recently appeared in the literature. We report the experience of 2 operative cases of myelopathy due to retroodontoid pseudotumor.
【Case 1】A 73-year-old man had experienced neck pain, hand numbness, hand clumsiness and gait difficulty. Cervical lateral adiography revealed atlantoaxial subluxation, and cervical MRI demonstrated a retroodontoid mass and severe cord compression. MRI also revealed subaxial canal stenosis due to spondylosis. After C1 laminectomy, C1 lateral mass・C2 pedicle screw fixation was performed. Simultaneously, the patient underwent C3-6 laminoplasty and C2, C7 partial laminotomy.
His symptoms improved significantly after surgery and on MRI, 1 year after operation, the retroodontoid pseudotumor had disappeared.
【Case 2】A 79-year-old man had experienced neck pain, hand numbness, hand clumsiness and gait difficulty. Cervical lateral radiography revealed no atlantoaxial subluxation. Cervical MRI demonstrated a retoroodontoid mass and severe cord compression. MRI also revealed subaxial canal stenosis due to spondylosis. The patient underwent C1, C2 laminectomy, C3-6 laminoplasty and C7 partial laminotomy. Because there was no instability, we did not perform fixation. His symptoms improved significantly after surgery but on MRI, 1 year after operation, the mass still remained.
【Discussion】We selected the operative method for atlantoaxial instability. In each case symptoms improved significantly after operation. On the other hand, only the fixation case demonstrated disappearance of the pseudotumor. Further follow-up and accumulation of future cases is necessary.
Surgical Treatment with a Combination of Open-Door Laminoplasty and
Foraminotomy for Cervical Spondylotic Amyotrophy
Takao MOTOSUNEYA, et al.
We performed surgical treatment with a combination of open-door laminoplasty and foraminotomy for patients with cervical spondylotic amyotrophy(CSA). There were 6 patients(5 males, 1 female, Age: 38-74, average 61.7 years, followup:
3-7, average 5 months). Foraminotomy was performed followed by tension-band laminoplasty with expansion at the symptomatic side. The resection area of the superior articular process was limited to the medial half.
The numbers of decompressed nerve roots were 2 for C5, 5 for C6, and one for C7. The average duration of surgery was 172 minutes, and the average volume of blood loss was 456 ml. There were no complications during surgery. Five patients improved more than one level by the manual muscle test, and no patients showed postoperative instability or spondylolisthesis.
Even now, the pathomechanism of CSA is unclear, and several hypotheses are proposed: myelopathy, radiculopathy, or both together. At present, anterior spinal fusion or posterior decompression is performed for CSA. We consider that a combination of open-door laminoplasty and foraminotomy can offer decompression of both the spinal cord and the nerve root. Postoperative instability can be avoided by taking care that the resection area of the superior articular process dose not extend beyond the medial half. This procedure offered good results and was useful.
Nerve Root Palsy after Laminoplasty with Corrective Fusion Using Pedicle Screw for Cervical Myelopathy
Go YOSHIDA, et al.
This retrospective study was conducted to analyze the nerve root complications in patients with cervical spondylotic myelopathy with instability or kyphosis treated by using cervical pedicle screw(CPS) systems. One hundred and fortyfour patients underwent only cervical laminoplasty(CLP) and 13 received added corrective surgery using CPS. In the CPS group, pre- and post-operative listhesis, segmental kyphosis and intervertebral foramen were measured by coronal and parasagittal views of the reconstruction CT. Post-operative cervical root palsy occurred in 6(4.2%) of the CLP group and 4(31%) of the CPS group. These cases of root palsy of the CPS group were three C5 and one C7 palsy. Additional foraminotomy was performed in all patients who showed nerve root palsy, and all showed neurological improvement. In the post-operative CT analysis and intra-operative findings, we could not see the penetration of the screws, so we considered that nerve root palsy was caused by iatrogenic foraminal stenosis after corrective surgery. In this study, post-operative listhesis and segmental kyphosis were improved and intervertebral foraminal widths, heights and axis lengths were decreased by correction. Avoiding excessive reduction, sufficient pre-operative imaging of the intervertebral foramen and foraminotomy of all segments can effectively prevent this type of nerve root complication.
Unilateral Microscopic Decompression for Spinal Canal Stenosis in Upper Lumbar Lesions
Hideaki MURATA, et al.
The purpose of this study is to report the methods and the short-term results of microscopic decompression through unilateral approach in patients with lumbar canal stenosis, including L3/4, L2/3 and L1/2.
[Materials] The subjects were 16 patients. The average age was 73 years. A total of 33 levels were decompressed.
[Results] The mean operation time was 94 minutes per level, and blood loss was 109 ml per level. The mean JOA score was 12 points before surgery, which improved to 27 points after surgery.
[Discussion and Conclusion] This microscopic decompression through unilateral approach would be useful for the treatment of lumbar canal stenosis, including L3/4, L2/3 and L1/2.
Surgical Outcomes of Microendoscopic Discectomy for Lumbar Disc Herniation
―A Comparison with Love's Method―
Kimiaki SATO, et al.
Surgical outcomes of microendoscopic discectomy(MED) were evaluated by comparing it with Love's method for lumbar disc herniation at L4-5 or L5-S1. Fifty-three patients treated by the MED method and 48 patients by Love's method, as a control group, were included in this study. Each operation in both groups was performed by the same surgeon. Surgical outcomes in both groups were compared on the basis of operative duration, anesthetic duration, blood loss, total dosage of analgesics administered, or patient-based outcome using the Visual Analogue Scale(VAS) and Roland-Morris Disability Questionnaire(RDQ). While no significant difference in operative duration, anesthetic duration, VAS or RDQ score were found, blood loss and total dosage of analgesics administered were significantly lower in the MED group. It was consequently concluded that the MED method is a useful procedure for the treatment of lumbar disc herniation.
Clinical Results of Median Hook® in Thoracic and Lumbar Multi Segmental Posterior Fixation
for Osteoporotic Vertebral Collapse
Keisuke SHINODA, et al.
Purpose: The Median Hook(Medtronic) has been designed to set a laminar hook on an upper instrumented vertebra where pedicle screws have been inserted. The aim of this study is to evaluate the short term results of thoracic and lumbar vertebral posterior fixation using pedicle screws and Median Hook®.
Patients and methods: Between May 2006 and May 2007, six consecutive patients(4 women and 2 men) were treated by using the Median Hook. Ages ranged from 64 to 75 years with a mean of 71 years. The mean follow-up duration was 7 months. Causative disease etiologies were thoracic compression fracture in two patients, lumbar compression fracture in two, metastatic spinal tumor in one, and lumbar degenerative scoliosis in one. All patients had osteoporosis and required multilevel posterior fixation.
Results: During follow-up periods, compression fractures occurred in three cases at the upper instrumented vertebra in two patients and outside the fixation levels in one. Of these, one case required revision surgery.
Discussion: Possibly due to injury of inter-and supraspinous ligaments, compression fracture frequently occurred in the upper instrumented vertebra. This was considered to be a major disadvantage of Median Hook®.
Posterior Decompression by Double-Door Laminectomy for Ossification
of the Ligamentum Flavum at the Thoracic Spine
Hironobu YAMADA, et al.
Twelve patients(11 males, one female, average age 56.9 years, average follow-up period 7.5 months) with thoracic myelopathy due to ossification of the ligamentum flavum(OLF) underwent posterior decompression by double-door laminectomy. OLF was mainly located at the Th10-12 levels. After resecting the spinous processes and thinning the laminae deep to the inner cortex, the laminae were split centrally and bilaterally at the inner border of the pedicles. By opening the split laminae bilaterally, the adhesion between the dura mater and OLF was dissolved and both the split laminae and OLF were completely removed. In patients with severe ossified adhesion, the dura mater was removed but the arachnoid membrane was preserved. The average operation time was 2 hours and 48 minutes and the average volume of blood loss was 354 ml. Adhesion was observed in 4 patients. Preoperatively, one patient was classified as Frankel B, 2 patients as C, and 10 as D. Postoperatively, three patients were classified into as Frankel D, and 9 as E. Five patients with preoperative bladder or bowel disturbance recovered postoperatively. Posterior decompression by double-door laminectomy for thoracic OLF is a safe procedure, because the decompression site can be clearly visualized.
Selective Posterior Fusion for King Type II or Lenke Type 1 of Adolescent Idiopathic Scoliosis
Masafumi MACHIDA, et al.
Despite numerous clinical publications related to the correction of adolescent idiopathic scoliosis, there is still no consensus on the optimal surgical plan for each curve type. We performed selective posterior fusion with hooks and pedicle screws for King type II or Lenke type 1 of adolescent idiopathic scoliosis. The pedicle screws were placed at lower to apex, the hooks at the proximal part of thoracic spines. The correction maneuver was applied with translation, derotation at the concave side and push-prone at the convex side. Furthermore, the tilt angle of the lowest instrumented vertebra was corrected to the neutral position. Our results suggested that hybrid materials with hooks and pedicle screws allowed for better correction in the coronal and sagittal planes and shorter fusion levels than previous methods.
A Case of Spinal Dural AVF at the Craniocervical Junction
Keiichi AKATSUKA, et al.
An operative case with myelopathy due to a spinal dural arteriovenous fistula(dural AVF) at the craniocervical junction is presented. An 80-year-old woman suffered sensory disturbance of the trunk and lower extremities, gait disturbance, and clumsiness after treatment for an ankle fracture. Her symptoms became exacerbated, and cervical MRI showed a diffuse intramedullary hyper-intensity signal extending to the medulla and a flow-void signal on the rostral and dorsal surfaces of the spinal cord. A spinal dural AVF was suspected and she was admitted to our hospital. Neurological examinations showed paraplegia in the lower extremities, sensory disturbance in the area below the T3 level, and clumsiness. Bilateral angiography of the vertebral arteries showed perimedullary venous dilatation in the rostral and dorsal surfaces supplied from the fistula originating at the left intradural vertebral artery just after penetrating the dura. At first, endovascular treatment was tried, but the fistula could not be occluded. Surgical treatment was then performed and a few fistulae were identified and ligated, so that the dilated perimedullary vein changed to the normal color. Postoperatively the intramedullary hyper-intensity in the T2 weighted MRI gradually disappeared, but her paraplegia was not much improved.
Wrong-Level Decompression of Cervical Lamina
―Report of 2 Cases―
Satoru SHIMIZU, et al.
Although decompression for vertebral degenerative disorders is common practice, the procedure is sometimes performed at the wrong level.
We describe 2 cases of treatment by decompression at the wrong level of the cervical lamina, i.e. at 1 and 2 levels caudal to the intended level, respectively. The latter patient underwent re-operation.
Misidentification of the appropriate decompression level was mainly attributable to misidentification of the C2 spinous process. In some instances, the characteristics of the C2 spinous process, an important anatomical landmark, are similar to those found at lower levels. In addition, in the flexed neck position, there may be a relative reduction in the height of the C2 spinous process. The surgeon must be therefore alert to the possibility of this type of misidentification, because in individuals with vertebral degenerative disease, the lack of a clearly visible lesion in the spinal canal renders proper identification difficult.
Intrathecal Baclofen Therapy for Severe Spasticity
Yasutaka TAKAGI, et al.
[Purpose] Baclofen is a GABAB agonist that is administered spinally through an implanted drug delivery device to treat spasticity. In this study, we present the surgical technique and clinical results of intrathecal baclofen therapy.
[Materials and Methods] Nine patients were admitted for a screening trial to determine whether a single intrathecal baclofen injection reduced their spasticity.
Of the nine patients, seven were cervical cord injuries, one thoracic cord injury, and one hereditary spastic paraplegia. The Ashworth score to assess muscle tone was obtained for the lower extremities. All patients were considered to show a clinically significant response, and seven were offered implantation of a programmable subcutaneous pump for continuous intrathecal baclofen injection.
[Results] The mean Ashworth score for rigidity decreased from 2.72±0.67 to 1.57±0.25(p<0.01). Without painful muscle spasms, the patients were more comfortable.
[Discussion and Conclusion] Baclofen is an agonist of the inhibitory neurotransmitter gamma-aminobutyric acid and acts at the spinal cord level, primarily by inhibiting the release of excitatory neurotransmitters. Baclofen is lipophilic and crosses the blood-brain barrier poorly, and is therefore ideally administered intrathecally. It works in essence as a substitute for gammaaminobutyric acid, which should be released by the descending inhibitory impulses. In these cases, reduced spasticity resulted in improved levels of physical activity, decreased pain, and augmentation of sleep.
Intradural Thoracic Arachnoid Cyst in Three Operative Cases
Eiichiro HONDA, et al.
The arachnoid cyst in the spine may be congenital, but seems to cause various symptoms due to some events such as trauma, inflammation or delivery. Posterior location to the spinal cord was found in about 80% of patients, whose symptoms were mainly dysesthesia and radicular pain on the trunk and extremities. These symptoms can not practically be improved by operation. On the other, motor function disorder due to the 20% of anterior arachnoid cysts tends to be improved by surgical intervention. We report 3 cases of intradural thoracic spinal arachnoid cyst. In all cases the cyst was in posterior location. Case 1 was a 48-year-old female, who complained of severe back pain. MRI showed that the cord was compressed anteriorly at T3 level. Case 2 was a 57-year-old male, who had a main symptom of slowly progressive dysesthesia running from both legs to T5 level. MRI showed anterior compression with syrinx. Case 3 was a 69-year-old female, who had mild dysesthesia in both feet. All cases had only sensory disorder without motor dysfunction.
In extradural arachnoid cyst in the thoracic region, the dural defect is closed, which is complete operation. However, surgical intervention to intradural arachnoid cyst is still controversial, because of possible recurrence of arachnoid cyst. Our operation should be performed with 2-4 laminoplasty and thick arachnoid membrane excised as widely as possible. In this procedure, multiple septa in the arachnoid cyst and tethered cord due to tubercula are found. However, arachnoid membrane tightly adherent to the spinal cord should not be removed diligently, because this dissection may invite new symptoms. The dura may be closed with arachnoid membrane for protection against recurrence of the cyst
A Case Study of Spinoplasty for Lumbar Degenerative Spondylolisthesis
Shinjiro TOMITA, et al.
The purpose of this study is to evaluate the clinical result of Spinoplasty(reconstruction of spinous process) for lumbar degenerative spondylolisthesis.
Materials and Methods: One patient with left sciatic pain and lumbago due to lumbar degenerative spondylolisthesis was treated by spinoplasty after fenestration. The case was a 60 year old female with L4 degenerative spondylolisthesis and L3/4 canal stenosis. Fenestration was done at L3/4 and L4/5 lamina under neutral position. L4 spinoplasty was then applied. We evaluated the change of X-ray, pain and JOA score. Follow-up period was six months.
Results: Low back pain decreased from seven to two points on the visual analog scale. JOA score also improved from 12 to 25 points. After operation, the stability of the sagittal alignment improved.
Discussion and Conclusion: We performed a less invasive surgical procedure. Spinoplasty will be both feasible and useful in the treatment of lumbar degenerative spondylolisthesis.