Surgical Technique for Spine and Spinal Nerves
Vol.7 No.1(2005)

Main Theme 1：Cervicothoracic Junctionr

Approaching the Upper Thoracic Vertebrae without Sternotomy - MRI Analysis - Tsuyoshi OKUDAIRA, et al. [Purpose] We witnessed a case of T1 metastatic tumor where the lesion was easily approachable anteriorly without sternotomy. [Material and Methods] The vertebral level tangential to the suprasternal notch and the lowest end plate level visualized in its entirety above the sternum were determined from 100 consecutive midsagittal cervical MRI studies. [Results] In 72 out of 100 cases, T2 is above the sternal notch. In 10 out of 100 cases, T3 is above the sternal notch. [Discussion and Conclusion] Since, even with the extended approach, T3 is the lowest level approachable by sternotomy, the simple suprasternal approach should be considered first. However, care should be taken regarding the degree of thoracic kyphosis, which can be an obstacle to the anterior approach. A preoperative midsagittal MRI can identify the thoracic vertebrae above the sternum, thereby determining whether the suprasternal approach is feasible.

Surgical Treatment for Metastatic Tumor of the Cervicothoracic Junction Atsushi ONO, et al. Purpose: The surgical outcome of operation for metastatic tumor of the cervicothoracic junction(C7-T2) was retrospectively evaluated. Methods: The subjects were 13 patients who had suffered from metastatic spinal tumor of the cervicothoracic junction and had undergone surgical treatment. The primary tumors were cancer of the lung(4), breast(3), colon(2), prostate(1), kidney(1), uterus(1) and unknown(1). Ten patients were treated with palliative posterior decompression and stabilization. Three patients were treated with posterior decompression and stabilization and anterior intralesional excision and stabilization using the hydroxyapatite spacer for metastatic tumor in C7. The postoperative improvement of neurological function and reduction of pain, the rate of recurrence of the spinal tumor and paralysis, and other complications were evaluated. Results: Ten patients showed improvement in their neurological function. Eleven patients obtained alleviation of the pain. Three patients experienced local recurrence of the spinal tumor and spinal paralysis. One patient suffered instrumentation failure. Conclusions: In this study, 3 out of 13 patients experienced local recurrence of the spinal tumor and spinal paralysis. It is necessary to consider the indications for surgical treatment and surgical strategy for metastatic tumor of the cervicothoracic junction

Hemilaminectomy and Bilateral Decompression at C7 or Upper Thoracic Region by Using Surgical Microscope on the Cervical Laminoplasty Ken YAMAMOTO, et al. We report a new method of microscopic laminoplasty preserving the maximum amount of posterior supporting structure at the cervico-thoracic spine to minimize operative invasion. We treated 14 patients with OPLL and CSM by bilateral decompression via a unilateral approach to C7 or upper thoracic spine. Neurological improvement was demonstrated in all patients. Postoperative hollow skin depression along incision at the cervico-thoracic junctions disappeared and postoperative axial symptoms were relieved compared with the conventional method. We consider that this is a new laminoplasty procedure for stenosis at the cervico-thoracic spine, which minimizes invasion and can reduce postoperative axial symptoms

Main Theme 2：Craniocervical Junction The Suboccipital Transcondylar Approach to the Anterior Craniocervical Junction Yoshinori SHIMAMOTO, et al. (Purpose) The suboccipital transcondylar approach to the anterior craniocervical junction is presented, as performed on a cadaveric specimen.(Results) C1-hemilaminectomy and drilling of the posteromedial portion of the occipital condyle and lateral atlantal mass are essential to expose lesions of the anterior craniocervical junction down to the spinal canal, and excellent control of the vertebral artery can be obtained intra and extradurally with this approach.(Discussion) This approach is indicated for tumors located anterior to the craniocervical junction, and anterolateral intrinsic lesions of the lower brain stem. The disadvantage of this approach is the risk of postoperative instability. However, this complication can be avoided by preserving at least two thirds of the articular surface of the condyle

Three Cases of Dural Arteriovenous Fistula at the Craniocervical Junction Eiichiro HONDA, et al. We observed three cases with dural AVF at the craniocervical junction. Craniocervical dural AVF is associated with a high frequency of subarachnoid hemorrhage, compared to thoracic and lumbar cases. All patients were male and between 61 and 71 years old. One presented with subarachnoid hemorrhage and the other two complained of slowly progressive ischemia. Common findings on angiography in all cases showed an abnormal dilated radiculomedullary draining vein located in the left C1 portion close to the vertebral artery and connected to the coronal venous plexus and intracranial vein.All patients underwent operation and the draining vein was easily interrupted. The postoperative course was uneventful. Arachnoid hemorrhage due to dural AVF at the craniocervical junction may suddenly become fatal, while developing ischemia may also lead to serious morbidity and become irreversible in the final stage. For these reasons, craniocervical dural AVF should be diagnosed at an early stage, with examination by MRI and detailed ofbervation of the clinical course

Postoperative Morphological Changes of Spinal Cord and Syringomyelia in Patients with Chiari Malformation Futoshi SUETSUNA, et al. The purpose is to examine the postoperative morphological changes of the spinal cord and syrinx in patients who underwent FMD with removal of the outer layer of the dura mater for syringomyelia associated with Chiari malformation. 11 patients(group 1) with shrinkage of the syrinx and 6 patients(group 2) without shrinkage of the syrinx were investigated. The mean follow-up period was 4.9 years. Radiographic parameters included areas of cross section, AP and transverse diameters of spinal cord and syrinx. Surgical outcomes included the revovery rate using the JOA score. The rates of shrinkage of the area of cross section in group 1 were 15.2% in the spinal cord and 45.4% in the syrinx. Postoperative rates of shrinkage of the spinal cord were 16.2% in AP diameter and 1.9% in transverse diameter. Postoperative rates of shrinkage of the syrinx were 33.5% in AP diameter and 28.3% in transverse diameter. The average recovery rates were 28.5% in group 1 and 37.8% in group 2. The rate of shrinkage of the syrinx was higher than that of the spinal cord. The rate of shrinkage of AP diameter in the spinal cord was higher than that of transverse diameter. However, there was no difference between the rates of shrinkage of AP and transverse diameters in the syrinx

Posterior Fixation with C1 Lateral Mass Screw for Atlanto-Axial Subluxation Due to Rheumatoid Arthritis Kentaro SHINOHARA, et al. Although posterior transarticular fixation, as reported by Magerl for atlanto-axial subluxation, has been an accepted method of rigid internal fixation, this technique carries the risk of injury to the vertebral artery. It has been reported that a new technique for individual screw placement at C1 and C2 minimized the risk and obtained rigid fusion of the atlantoaxial complex. We report five cases treated by this new technique. Up to now, however, the starting point for screw insertion has been controversial. Our entrance point for screw insertion was at the intersection of the inferior border of the posterior C1 arch and the midpoint of the C1 lateral mass. Althogh the post-operative time is short, there has been no instrumentation failure. In comparison with the Magerl method, this technique has the advantages of decreased risk of injury to the vertebral artery and reduction of C1 subluxation by applying a correction force through C1 screws

Occipitocervical Fusion in Patients with Rheumatoid Arthritis Using Hook and Plate-Rod System(CCD-Cervical Yoichi JIN, et al. We report the clinical results of occipitocervical fusion(O-C fusion)in patients with rheumatoid arthritis(RA) using the hook and plate-rod system(CCD-cervical). Although the results are short-term, comparison is made with the Onomura method, which is the conventional method, and some discussion of the literature is added. All patients were fitted with a halo-vest preoperatively and alignment was corrected as much as possible. We regard patients who obtained an inadequate reduction of AAS or VS as needing O-C fixation. All six cases were female, and we classified them into 3-A(four patients)and 3-B(two patients) according to the classification of Ranawat. This study included three different methods. Group C comprised two cases treated with the CCD cervical system, Group A comprised two cases treated by the Onomura method using AO mini screws, and Group S comprised two cases treated by the Onomura method using songer cable. We usually performed laminectomy of C1 and decompression of the foramen magnum. The halo-vest was removed after operation in group C, in contrast to patients in groups A and S, who needed to keep it postoperatively for three or four months. Evaluation at six months postoperatively showed that the pain was improved one level according to Ranawat's scale in groups A and S, but the myelopathy was the same as before operation. Pain and myelopathy scales of all cases in group C(3-A) improved by more than one level. Most RA patients who need surgical treatment are unstable in their general condition; Therefore, their treatment should be less invasive in all procedures. As group C patients did not need halo-vest immobilization postoperatively due to strong tightening of cortical bone by the hook system and could maintain the alignment obtained preoperatively, this method was useful for the treatment of cervical myelopathy in patients with rheumatoid arthritis.

Usefulness of Image Guidance in Spinal Instrumentation at the Cranio-Cervical Junction Masakazu TAKAYASU, et al. (Purpose) To show the usefulness of an image guiding navigation system in spinal instrumentation at the craniocervical junction. (Materials and Methods) Since 1997, we used a navigation system in 20 cases among 48 spinal instrumentation operations at the cranio-cervical junction. Navigation systems(Stealth Station or Stryker's system) were used for C1/2 transarticular screw fixation in 13 and other anchor screws such as C2 pedicle, C1 lateral mass and so on in 7 patients. Three patients were younger than 15 years old. Four had an accompanying anomaly at the cranio-cervical junction. (Results) Surgical planning was performed preoperatively. In C1/2 transarticular screw fixation, screw insertion was judged dangerous on both sides and other fixation methods were used in 3 patients. In 6 patients, it was judged safe on both sides and in 4 only on one side. All screws were inserted safely along the planned trajectories under image guidance. Screw insertion was satisfactory under image guidance in other operations, such as C2 pedicle, C1 lateral mass, C7 translaminar screwing and so on. (Conclusion) Under image guidance, screw insertion at the cranio-cervical junction can be done precisely and safely, and indication of C1/2 transarticular or other screw insertion becomes wider for younger children, patients with anomaly or with little room for screw insertion.

Anterior Screw Fixation of a Odontoid Fracture with a Cannulated Screw System Using X-Tube and Radiance Illumination System Yasutaka TAKAGI 〔Purpose〕Anterior screw fixation of odontoid fractures is a technically demanding procedure for the prevention of operative complications. We report a case of odontoid fracture treated with a cannulated screw system using an X-tube and Radiance illumination system. 〔Materials and Methods〕A 19 year-old man suffered an Anderson-d'Alonzo type II～III odontoid fracture. A 3～4 cm skin incision was made over the C5-6 disc. With a 7 cm length X-tube, a fixed operative field was obtained. With the Radiance illumination and video monitor system, we could easily view the operating field. We used the universal cannulated screw system. The guide length was 190 mm; we inserted a 1.42 mm guide wire only once under anteroposterior and lateral C-arm imaging, and then we safely inserted a 42 mm 4.0 mm cannulated lag screw. 〔Results〕Operation time was 60 minutes. Blood loss was minimal. No intraoperative complications appeared. Two days after surgery, he could walk with a Philadelphia collar. 〔Discussion and Conclusion〕Etter reported a major complication rate of 17%(4/23) resulting from inappropriate use of this technique. We could safely perform anterior screw fixation with a cannulated screw system using the X-tube and Radiance illumination system. These systems are very useful for anterior screw fixation of odontoid fractures.

A New Technique of Muscle-Preserving Atlantaxial Fixatiton Atsuto SAKAMOTO, et al. We developed a new operative technique for posterior atlantoaxial fixation with less invasion of the deep extensor musculature. The subjects were three rheumatoid arthritis patients with atlantoaxial subluxation. The mean age was 67 years, and the mean postoperative follow-up period was 10.3 months. Reduction was done as much as possible by a hydroxyapatite spacer in the C1-2 interlaminare, encircled with Teckmilon tapes, and fusion was performed by the Brooks and Magerl method. We analyzed the operative time, the volume of bleeding, changes of the C2-C7 angle, JOA score and axial pain. No patient had deterioration of vertebral alignment or axial pain after surgery. In the conventional posterior approach surgery for atlantoaxial dislocation, we are concerned about the development of complications such as deterioration of cervical vertebral alignment and severe axial pain. Although the follow-up period was short, we saw no deterioration of the vertebral alignment or axial pain. On the other hand, we needed a longer operation time than is usual in the conventional operations. The issue of our future studies is shortening of the operation time. This new muscle-preserving atlantoaxial fixation is a useful procedure that may prevent development of the usual complications.

Main Theme 3：Spinal Canal Stenosis Microendoscopic Decompression Using Contralateral Approach for Lumbar Spinal Canal Stenosis Yasuo MIKAMI, et al. In patients with narrow vertebral arches, it is difficult to perform decompression of the lumbar spinal canal while preserving the facet joints on the approached side. Using a contralateral approach, we carried out microendoscopic decompression of the lumbar spinal canal without damaging the facet joints. The subjects were 27 patients(mean age: 68.5 years) with lumbarspinal canal stenosis. The mean postoperative follow-up period was 12.6 months. Using the METRxTM spinal microendoscopic system, we performed decompression via a contralateral approach and endoscopically resected the thickened ligamentum flavum and the bone spurs from the facet joint. The mean operative time was 141 minutes per vertebra, and the mean bleeding volume was 76 g. The mean JOA score improved from 14.3 points(preoperative) to 25.3 points(postoperative). The VAS showed that the preoperative pain and surgical wound pain became less than 10mm within three days after surgery in 21 out of the 27 patients. Postoperative CT scanning revealed no damage of the facet joints after the decompression procedure. There was little postoperative pain, and the short term results were good. Microendoscopic decompression by a contralateral approach for lumbar spinal canal stenosis is a minimally invasive surgery technique that has the advantage that it can preserve facet joints.

Microendoscopic Decompressive Laminotomy with Facet Preserving Technique for Lumbar Spinal Canal Stenosis Yukihiro NAKAGAWA, et al. Purpose: The aim of this study was to evaluate the clinical outcome of lumbar spinal canal stenosis treated by microendoscopic decompressive laminotomy with facet-preserving technique. Material and methods: From 2001 to 2004, seventy-one consecutive patients underwent posterior microendoscopic surgery for lumbar spinal canal stenosis. Twenty spondylolisthesis patients were included. There were 37 males and 34 females, and the average age was 66.1 years. Clinical outcomes were evaluated by the Japanese Orthopaedic Association scoring system for lumbar disease. Moreover, operation time, blood loss, use of diclofenac suppositories and intra- and postoperative complications were investigated. Results: Mean preoperative JOA score was 14.8 and postoperative JOA score was 22.3. Operation time was 79.5 minutes per one level decompression, and mean blood loss was 51.3 gram. The use of diclofenac suppositories was 0.34 times. Intra and postoperative complications were due to one misjudgment of the vertebral level, three dural tears, one infection due to drain problems, two cases of liquorrhoea, and two postoperative epidural hematomas. Discussion: Clinical outcomes of posterior microendoscopic decompressive laminotomy for lumbar spinal canal stenosis were the same as those of conventional open decompression methods. Postoperative instability due to the decompressive maneuver is little in posterior microendoscopic surgery, and the facet joints were preserved. Microendoscopic decompressive surgery is a minimally invasive technique; therefore the extent of operative incision, blood loss and postoperative use of diclofenac suppositories were minimized. Conclusion: Microendoscopic decompressive laminotomy with facet-preserving technique is an ideal decompressive method for lumbar spinal canal stenosis.

Endoscopic Decompression for Adjacent Level Degeneration after Lumbar Instrumentation -2 Cases Report- Akira ITOI, et al. 【Purpose】We performed endoscopic decompression for adjacent level degeneration after spinal instrumentation. We got comparatively good results. 【Materials & Methods】Case 1; A 72 year old man. We performed endoscopic decompression using METRx MED system for L2/3, 3 years and 4 months after L3～L5 PLF with pedicle screw systems. Case 2; A 54 year old man. We performed endoscopic decompression for L1/2～L2/3, 2 years and 9 months after L3～L5 PLIF with pedicle screw systems. 【Results】We could get good decompression without interfering with the pedicle screw systems. Case 1; the patient had no intermittent claudication. JOA score was 24 points, 6 months after the operation. Case 2; low back pain still remained, but foot pain had decreased. 3 months after the operation, his JOA score was 17 points. 【Conclusion】Additional spinal instrumentation was necessary for a salvage operation for adjacent level instability and stenosis after spinal fusion. If there is no instability, we think that stenosis due to adjacent level degeneration could be salvaged by decompression surgery alone. In these 2 cases, endoscopic decompression was possible without interference with spinal instrumentation. We consider that it is a good choice as a salvage operation method for adjacent level degeneration.

Microscopic Unilateral Circumferential Decompression(MUD) for Lumbar Spinal Canal Stenosis -Clinical and Radiological Review- Kazuyo YAMAUCHI, et al. Microscopic unilateral circumferential decompression(MUD) has been adopted for lumbar SCS(spinal canal stenosis) in our institute. The purpose of this study is to clarify the advantages and disadvantages of this procedure. Materials include 19 SCS patients who underwent MUD from May 2002 to August 2003. Eight were males and 11 females. The mean age was 71 years. We operated at 32 disc levels of the 19 patients. Radiological assessment included invasion of the facet joint of the approach side, lateral recess decompression, and dural tube expansion, using pre- and postoperative 3D-CT and MR myelogram images. Postoperative mean score of JOA improved 23.3 points from 13.1 points pre-operatively. There were several complications including 1 fracture of the spinous process, 1 lamina fracture and 5 dural sac tears. The facet joint on the approach side was 100-75% preserved at 11 disc levels, 74-50% at 13 and 49-25% at 5. Decompression of the lateral recess was accomplished completely at 28 disc levels and incompletely at 4. The Dural sac expanded completely in 9 of the 19 patients. Spondylolisthesis progressed in 2 patients. The surgical outcomes of MUD were almost all satisfactory in the shortterm follow-up.

Microsurgical Hemilaminectomy and Total Flavectomy for Lumbar Canal Stenosis Compared with PLIF and TLIF Naoki ASAMI Purpose: PLIF surgery is very useful because both decompression and fusion can be achieved at the same time. But it also brings some problems such as postoperative pain, blood loss, and infection. Materials and methods: The author reviewed the results of microsurgical hemilaminetomy and flavectomy, comparing them to PLIF and TLIF. He examined 155 cases of PLIF and 15 cases of microsurgical hemilaminectomy decompression from January 1999 to May 2004. Results: The blood loss was below 100 ml in all the cases of hemilaminectomy even at 4 levels, and patients could walk and move without medication on the next day. On the contrary, most of the patients with PLIF could not walk or move without pain-killers, and blood loss was about 200 ml per level. Discussion: The symptoms of lumbar canal stenosis are caused by many factors such as disc bulging, facets and yellow ligament hypertrophy. The author believes that all these factors can deteriorate with instability. Operative procedures are a kind of destruction, even when using microsurgical decompression. The surgeon must mention to patients that fusion may be added postoperatively, especially in active and younger cases.

Microsurgical Posterior Decompression for Lumbar Canal Stenosis Minoru HOSHIMARU, et al. (Objective) It is important in the treatment of lumbar canal stenosis to decompress the dural sac and nerve roots sufficiently while preserving the zygapophyseal joints. In this study, our surgical procedure of posterior decompression under an operating microscope is described and its usefulness is discussed.(Patients and Methods) Fifty-three patients with lumbar canal stenosis were treated between August 2002 and April 2004: there were 18 women and 35 men, ranging from 32 to 83 years of age(mean 64 years). Patients with instability of the lumbar spine underwent PLIF and were not included in this study. Under a microscope, a thin layer of the lamina covering the yellow ligament was removed with a high-speed burr and the yellow ligament was removed en bloc. The medial surface of the pedicle was exposed in all cases and it was partially removed when there was no space between it and the nerve root.(Results) Partial pediculectomy was added in 31 cases. Symptoms of all patients improved. The average JOA score was 13.0±5.2 before surgery and it increased to 23.5±4.9 at the time of discharge(P＜0.01).(Conclusions) Our technique for lumbar canal stenosis provides a good surgical result.

Clinical Study of Upper Lumbar Disc Herniation Using MED System Kazuhiro MAIO, et al. The purpose of this report is to evaluate the clinical outcome of the microendoscopic discectomy(MED) system for upper lumbar disc herniation. From September 1998 to December 2003, 402 consecutive patients underwent the MED system for lumbar disc herniation. Among them, 10 patients were treated by this system for upper lumbar disc herniation. The affected levels were two at L1/2, seven at L2/3, and one at L2/3 and L4/5. We investigated operation time, blood loss, and the Japanese Orthopedic Association score(JOA score) for low back pain. The mean operation time was 67.3 minutes. The mean blood loss was 23 g. The mean JOA score improved from pre-operative 13.0 to post-operative 26.1. There were no intraoperative complications. The conventional procedures for upper lumbar disc herniation are anterior decompression and fusion or facetectomy with posterolateral fusion, and osteoplastic hemilaminectomy without fusion. Those procedures, though effective are more invasive and need a brace and bed rest. The MED system is less invasive than the conventional procedures. It is important that we consider the anatomical specialty of the upper lumbar spine. Our results showed that the MED system is beneficial for the treatment of upper lumbar disc herniation.

A Novel Method of Repair for Spondylolysis Using Pedicle Screw and Claw System -Preliminary Report- Yoichi AOTA, et al. In an attempt to the improve fusion rate in direct repair of spondylolysis, we developed a new fixation technique using a pedicle screw and claw system. A rigid and secure hold of the floating lamina was obtained by hooks placed in a claw configuration. Applying compression force, the claw was connected with poly-axial pedicle screws. This technique was undertaken in five patients who had painful lumbar spondylolysis. Four had spondylolysis at L5 and one at both L3 and L4. Followup CT was obtained in 2 patients after surgery. Solid bone fusion was obtained in both cases. Compared with the method using pedicle screws and hook, our method is considered to afford higher rigidity. However, connection between the claw and pedicle screws is more difficult. To facilitate this connection, poly-axial pedicle screws were necessary. Rods were maximally bent laterally to connect with the pedicle screws. In conclusion, this new method is feasible and can be assumed to ensure solid bone fusion.

Selection of Surgical Methods in Lumbar Spondylolysis Manabu GOTO, et al. 152 patients with spondylolysis visited Meijo Hospital from 1992 to 2003. Of them, 21 patients needed operation in spite of conservative therapy for several months. Sixteen patients were males and five were females. Their average age at the time of the surgery was 33.2 years and the average follow-up period was 30 months. The levels of defects were L5 in 14 patients, L3 in one, both L3 and L5 in 3, and both L4 and L5 in 3. All patients complained of low back pain and 19 patients also complained of leg pain and/or sensory deficit. Posterior spinal fusion was selected for 13 patients; direct repair of the defect in the pars was selected two cases, combined procedures of spinal fusion and repair of defect in 4 cases, and decompression in two cases. The strategy of surgical treatment for spondylolysis has been either spinal fusion or direct repair of the defect in the pars, selected according to the presence of disc degeneration distal to the spondylolysis. It is important to select the proper surgical intervention for patients with spondylolysis, considering the pathomechanism which has caused the patients' symptoms.

Endoscopy Assisted PLIF for LSCS Koji SATO, et al [Purpose] We used METRx(tube retractor and endoscope system) for lumbar spinal canal stenosis(LSCS). We describe our method. [Objective] 14 cases were treated by micro-endoscopic decompression surgery in 2002-2004. The indications were onelevel lesion, low instability and less than 15 degrees ROM. There were 8 males and 6 females, average 67 years old. There were 4 cases of L3/4, 10 cases of L4/5. 3 cases underwent only decompression, 4 cases also facet fusion by PLLApin, and 7 cases also facet fusion by PLLApin and inter-body fixation with a cage. [Methods] We used the METRx system under general anesthesia and did decompression on one side, then used a wonder tube for medial oblique approach. We used an X-tube and 18 mm tube. We reviewed the about operation time, bleeding, quantity of postoperative analgesis, XP, JOA, and SF-36. [Result] Average operation time was 121 minutes. Bleeding was 81 g. The quantity of postoperative analgesis varied. JOA score was improved to 26 from an average of 17; all eight items were similar, and SF-36 too was improved. Dura mater was damaged in 3 cases, and there was a slight neurological deficit in one case. [Conclusion] This MED-PLIF method is an option for operation for stable LSCS.

Use of X-tube for Posterior Lumbar Interbody Fusion Takahiro SANADA, et al. We performed PLIF and pedicle screw fixation using an expanding tubular retractor(X-tube). We attempted to determine whether PLIF with X-tube was less invasive than open standard surgery. 1-level PLIF with X-tube was performed in 11 patients for degenerative spondylolisthesis, isthmic listhesis, and discogenic pain. Bilateral 3-cm paramedian incisions were made at the level of the operation. A 26-mm tubular retractor(X-tube) was inserted, and PLIF and pedicle screw fixation were performed through the X-tube. 1-level standard open PLIF was done in 13 patients for degenerative spondylolisthesis. Operation time, blood loss, body temperature change, CRP one week after operation, hospital stay after operation, requirement of analgesics during the first postoperative week, and postoperative MRI findings of paravertebral muscles, especially the multifidus, were analyzed in both groups. In the X-tube group and open surgery group, the mean hospital stay after operation was 11.6 days and 18.5 days respectively. There was a significant difference between the 2 groups. There was a trend towards quicker normalization of body temperature, and less blood loss in the X-tube group, and X-tube cases showed less high signal intensity on post-operative T2-weighted MR images of the multifidus muscle. PLIF with X-tube may be less invasive in terms of hospital stay after operation and postoperative back muscle injury.

Free Papers Short Term Results of Selective Expansive Open-Door Laminoplasty Takashi TSUJI, et al. The purpose of this study was to evaluate the efficacy of a new surgical procedure called selective open-door laminoplasty(selective ELAP) for patients with cervical spondylotic myelopathy(CSM). Since 2001, a total of 20 patients underwent selective ELAP in our hospital. Seventeen patients with CSM who underwent conventional C3-C7 ELAP in our hospital before 2001 served as controls. The operative time, blood loss, recovery rates aaccording to Japanese Orthopaedic Association scores, cervical alignment(C2-C7 angle and Ishihara's curvature index) and C2-C7 range of motion were investigated. The mean operative time of selective ELAP was significantly shorter than that of C3-C7 ELAP(p＜0.05). The mean blood loss in selective ELAP was significantly less than in C3-C7 ELAP(p＜0.05). The mean recovery rate was 59% for selective ELAP and 52% for C3-C7 ELAP. There were no significant differences between preoperative and postoperative C2-C7 angles or Ishihara's curvature indices in the two groups. The postoperative C2-C7 range of motion averaged 78% of the pre-operative in the selective ELAP and 64% in the C3-7 ELAP. In conclusion, selective ELAP for CSM was less invasive than conventional ELAP. The preliminary results of this procedure were satisfactory.

Dynamic Analysis of Our Minimally Invasive Cervical Expansive Open-Door Laminoplasty Using a Spinoplastic Hydroxyapatite Spacer Shun-ichi KIHARA, et al. As surgical treatment for degenerative cervical spine diseases represented by cervical spondylosis, cervical disc herniation and OPLL, both anterior decompression(anterior fixation) and posterior decompression(laminectomy, laminonoplasty) are used depending on the individual situation. There has been no end to the discussion as to which technique is superior. We thought that we might be able to provide an answer to the discussion if we could develop a surgical technique which could solve the problems in the posterior method, by which decompression of wider areas is possible, and thus we developed a new technique. More than 800 patients have already undergone this surgery and no analgesics for postoperative nuchal pains have been required in almost all cases. As complications of surgery, postoperative infection was observed in only about 0.5% of the cases, and such complications as difficulty in controlling intraoperative bleeding, which is feared because of the small incision, and postoperative bleeding were not observed. The average amount of bleeding was as small as 15 ml. Breakage or deviation of the spacer was not observed either. Deformities of the spine, including kyphosis, were not observed in the postoperative course, and preoperative malalignments, such as kyphosis, were improved after surgery in some cases. We examined the corrective effect on alignment due to the shape of our spacer by computer analysis using two-dimensional models, and found that the turning force in the direction of the lordotic curvature of the vertebral body increased when our spacer was used. It also became obvious that this force could be adjusted by adjusting the shape, which supported our clinical results. As have been stated above, various surgical techniques for degenerative cervical spine diseases are proposed and applied clinically. There are merits and demerits in each technique and no conclusions have yet been drawn as to which technique is most useful. However, our surgical technique, which has eradicated the demerits of posterior decompression, is minimally invasive with favorable therapeutic results. It is a technique which can be mastered with certain training, and we think that it provides a direction in the discussion of the usefulness of surgical techniques for degenerative cervical spine diseases.

Microendoscopic Posterior Foraminotomy for Cervical Spondylotic Radiculopathy Kazunori NOMURA, et al. Purpose: We have introduced microendoscopic posterior foraminotomy for the treatment of cervical spondylotic radiculopathy. The purpose of this study was to evaluate the results of the surgery. Materials and Methods: Twelve patients who underwent microendoscopic posterior foraminotomy for cervical spondylotic radiculopathy after August 2001 were investigated. The mean follow-up period was fifteen months. Eleven cases were unilateral, single-level radiculopathy and one case was unilateral, two-level disease. Results: For single-level radiculopathy, the results were as follows: the mean operative time was 121.5 min, the median intraoperative blood loss 40 ml, the mean highest postoperative temperature 37.0℃, and the mean duration of fever 1.0 days. Ten patients could walk by the day following the operation. The mean hospitalization was 10.4 days. The mean Tanaka's score of cervical radiculopathy was 8.8 points preoperatively and 17.4 points at the latest follow-up. The two-level operation seemed more invasive than the single-level operation. Although transient neurological deterioration had been seen immediately after the two-level operation, the score of the disease improved up to the full mark(20 points) at the latest follow-up. Discussion and Conclusions: Microendoscopic posterior foraminotomy can achieve good clinical results as well as early discharge from hospital.

Radiological Assessment of Anterior Cervical Fusion Using Interbody Cage Toru OSAWA, et al. We performed anterior cervical fusion using boxed shape interbody cages(SynCage-C: Synthes Inc.), and evaluated the usefulness of this cage system with radiological assessment. The subjects were 32 patients(47 intervertebral spaces). The mean follow-up period was 10 months. Almost all cases achieved a solid union at final follow-up time(46/47:98%). The mean C2-C7 lordotic angle was －3.5° preoperatively, increased to 6.5° immediately after surgery, and decreased to 5.3° six months. The mean local lordotic angle was －6.1° preoperatively, increased to 0.7° immediately after surgery, and decreased to －0.8° six months. The mean intervertebral disc height of the fused level was 33.9 mm preoperatively, increased to 37.2 mm immediately after surgery, and decreased to 35.5 mm six months. Subsidence of the cage was greater in the patients in whom the osseous endplate was removed, and so it is important to preserve the osseous endplate. In post-operative alignment and bone union rate, the clinical results were favorable compared with other types of cervical fusion. There were no implant-related complications in this study. This cage system is recommended as a substitution for anterior fusion with autologous bone.

Clinical Short-Term Results of Percutaneous Vertebroplasty Shinjiro TOMITA, et al. Purpose: This purpose of study is to evaluate the short-term results of vertebroplasty with calcium phosphate cement(CPC) and hydroxyapatite(HA) sticks for osteoporotic vertebral fracture. Materials and Method: Eighteen patients(four male and 14 female) with compression fracture of the vertebral body were treated by percutaneous vertebroplasty under local anesthesia. CPC was used for five cases, HA sticks for 11 and both together for two. The patients were 76 years old on average. Follow-up periods ranged from 3 to 14 months. Complications occurred in five cases. Leakage of CPC out of vertebrae was found in four. One vertebra with adjacent fracture needed reoperation. We evaluated pain, vertebral compression and correction loss both pre-and postoperation. Results: The mean time of surgery was 59 minutes. Back pain decreased from 8.6 to 3.4 points on the visual analog scale. The degree of compression was 46.5% on average before surgery and improved to 30.0% on average after surgery, and to 44.5% at the last examination. The loss of correction was 3.4 mm on average. No instability was detected in any of the patients. Conclusion: We performed a less invasive surgical procedure. Radiographic and clinical findings at the final follow-up showed good results.

Transpedicular Vertebroplasty Using Spacers for Osteoporotic Compression Fractures Akiko NOMURA, et al. [Purpose] We have developed a new surgical technique, using special spacers for transpedicular vertebroplasty, to treat osteoporotic compression fractures with vertebral collapse, significant kyphotic deformity, and neurological compromise. This is a preliminary report on this technique. [Materials and Methods] We operated on five patients and followed them up for an average of 9 months(3-18). One patient presented with a compression fracture at Th12, three at L1, and one at L2. The mean preoperative kyphotic angle was 27 degrees. [Results] The average operation time was 264 minutes(215-290 m), with a mean blood loss of 342 g(220 650 g). The mean kyphotic angle improved to 7 degrees, and all patients were satisfied with their neurological improvement. [Discussion] There have been many reports on different surgical procedures to treat osteoporotic compression fractures with significant kyphosis. All procedures have their share of drawbacks: anterior-posterior procedures often induce severe morbidity, spinal shortening osteotomies result in dural buckling, and we have yet to encounter a biomaterial without possible unfavorable effects. Our new procedure allows for anterior structural support which enables easier correction of kyphosis, less buckling, and rigid support to treat osteoporotic compression fractures.

Two Cases of Spinal Reconstruction with Vertebroplasty for Osteoporotic Spine Fracture which Needed Nerve Decompression Makoto YANASE, et al. (Purpose) There are many problems in the operation for pseudarthrosis following osteoporotic vertebral compression fracture with neurological disorder. We did posterior decompression with reconstruction of the collapsed vertebra using the method of injection of calcium phosphate bone cement(CPC). At the same time, we used rods and polymer polyethylene cable wires as instrumentation. We report the clinical results in two cases. (Result) In both cases, instrumentation failures occurred, but we could get good clinical results without new vertebral collapse and neurological disorder. (Conclusion) We think that this operation for pseudarthrosis following osteoporotic vertebral collapse with neurological disorder is a good surgical option which involves the least operative invasion and possible complications.

Posterior Decompression and Fixation for OPLL of Thoracic Spine Koichiro NISHIKAWA, et al. (Introduction) Various operative procedures have been reported for extensive thoracic ossification of the posterior longitudinal ligament(OPLL). We have recently obtained satisfactory results in two cases by application of extensive decompression together with posterior fusion. (Case 1) A 40-year-old female with numbness of both lower extremities and urinary disturbance was referred to our department when she became unable to walk. For OPLL of Th1-Th7, extensive decompression with fusion was applied. (Case 2) A 55-year-old female was referred to our department when she became unable to walk. For OPLL from C2 to L1, extensive decompression from the cervical to the thoracic spine together with fusion was applied. (Discussion and Conclusion) As procedures for thoracic OPLL, posterior decompression, anterior decompression, and anterior decompression by posterior approach are available. However, intra and postoperative complications are not rare and there is no consensus on the operative procedure to be selected. We have carefully conducted extensive posterior decompression to the spinal cord under spinal cord monitoring for posterior shift of the spinal cord and confirmed decompression by intraoperative sonograply. Thereafter, with the aim of improving alignment of the thoracic spine and preventing kyphosis, extensive posterior fusion was supplemented by posterior instrumentation. Satisfactory results have thus been obtained.

How Do You Operate on Extramedullary Spinocranial Tumor? -Operative Prognosis of Spinal Meningioma and Nerve Sheath Tumor- Isao KITAHARA, et al. (Introduction) This is a retrospective analysis of our experience of operation of extramedullary cord tumor on the cord side of craniovertebral junction. (Materials and Methods) 28 cases of operation of tumors between the foramen magnum and C1, C2. Average age was 46 years, ranging from 10 to 79 years. 17 cases were male, 11 female. The pathological diagnosis in 7 cases was neurofibromatosis, in 20 neurinoma, in 8 meningioma. The location of the tumor was anterior and anterolateral in 7 cases, lateral in 19, and dorsal and dorsolateral in 2. The operation was done 34 times for the 28 examples. It was performed by posterior approach 19 times and by lateral approach 15 times. (Result) I performed foramen magnum decompression by C1/2 vertebral arch excision and exesion of tumor by the posterior approach method. Observation of the spinal cord in front was possible, but I could not view the opposite side for resection of tumor by the posterior approach. VA confirmation became possible at the last stage of tumor extraction, showing that the tumor was a Dumbbell tumor. I approached from the flank of C1, C2 by the lateral approach and opened a field by C1/2 vertebral arch excision and drilling of the lateral mass. I then observed the side from the front of the spinal cord at C1, C2 and, after a confirmation by VA of the C2 nerve root, resected the tumor. It is an advantage of the lateral approach that a field opens on what confirmation of the border of the spinal cord can easily identify as a tumor from the side and on the front of the spinal cord on the opposite side. I obtained an excellent result in 25 examples out of 28. Two patients of Neurofibtomatosis with malignant neurinoma showed temporary improvement after surgery, but died of associated malignany. (Conclusion) The results of operation for extramedullary spinocranial tumor showed that a combined backward and lateral approach was the best. We believe that patients who had extramedullary tumors both at the front and back to spinal cord can be treated surgically at lower risk when they are operated through lateral approach of cervical spine.

Intraoperative Radiotherapy for Spinal Cord Compression Due to Spinal Metastasis Taiji KONDO, et al. [Purpose] To improve local control of spinal metastasis, we have been conducting posterior surgery combined with intraoperative radiotherapy(IORT) for the treatment of spinal metastases. We report the surgical results of the patients, who underwent IORT because of severe neurological deficits. [Materials] 86 patients underwent IORT(88 procedures) for the treatment of severe spinal cord compression due to spinal metastases. All of them were non-ambulatory preoperatively and 83 cases(95%) were in an dvanced stage of spinal metastasis(Tomita's type 5, 6 and 7). [Methods] After posterior decompression, a single large dose of electron beam irradiation was delivered on the exposed metastatic lesion, while the spinal cord was protected using a lead shield. Posterior instrumentation was additionally performed in most of the patients. [Results] 76 cases(86%) obtained at least one level of neurological improvement according to Frankel's classification, and 69 cases(78%) became ambulatory postoperatively. The main factor causing non-ambulatory status postoperatively was deterioration of their general health. There was no recurrence of the lesions treated with IORT, which might cause deterioration of once regained ambulation. [Conclusion] The IORT procedure is a useful technique for treatment of spinal cord compression due to spinal metastasis, providing significant neurological recovery and preservation of ambulation.

Surgical Treatment of Vascular Intramedullary Cord Tumors Hiroshi TAKAHASHI, et al. We have operated hitherto 22 vascular intramedullary cord tumors(hemangioblastoma 10, cavernous angioma 10, one thrombosed AVM and one intramedullary schwannoma with hematomyelia). For hemangioblastomas, we obterated the feeders first and went through the boundary between the tumor and the cord. After that, we performed en bloc removal of the tumor. For cavernomas, if the tumor partly came to the surface of the cord, it was dissected from the surrounding normal cord using the space made by hemorrhages, and an en bloc extirpation was done. If it was located in the median part of the cord, the posterior median sulcus was opened and the tumor was removed in the standard way. When the tumor was located in the posterior horn, myelotomy at the outside of the dorsal root entry zone(DREZ) was done, and the tumor was removed. In the case with vascular-rich intramedullary neurinoma with hematomyelia, two operations with myelotomy were needed because of residual tumor after the first operation. When using the posterior approach, we should consider that the pyramidal tracts are located outside the DREZ and that even partial injury of the sensory tract can induce intractable postoperative pain.

4 Cases of Spinal Cord Biopsy Kimihiko MII, et al. Objective: To evaluate the clinicopathological findings of patients with unknown spinal cord lesions who underwent spinal cord biopsy. Methods: 4 patients who underwent spinal biopsies at Sagamihara hospital were studied. Case histories, radiological results, surgical notes, histological findings and outcomes were reviewed. Results: Spinal cord biopsies were performed for 3 patients with progressive neurological deficits and one patient with mild symptoms. High T2 signal intensity and moderate spinal cord expansion were identified. In one patient, Gd enhancement was not noted. A midline myelotomy provided access to the lesion in 3 cases, and the dorsal root entry zone was used in 2 cases. Pathological findings were multiple sclerosis in 2 cases, sarcoidosis in one, and gliosis(cause unknown) in one. Conclusion: Early diagnosis is necessary for effective treatment. However, a surgical risk of spinal cord biopsy is considerable. Decision making, therefore, is always difficult.

Origins of the Segmental Arteries in the Aorta -An Anatomic Study for Selective Catheterization with Spinal Arteriography- Satoru SHIMIZU, et al. Purpose: The segmental arteries(SAs) comprising the posterior intercostal, subcostal, and lumbar arteries, are gateways for the performance of selective spinal arteriography at the thoracolumbar level. We performed a study to clarify the anatomic relations between the origins of the SAs in the aorta and the vertebral column. Material and Methods: Five adult cadaveric aortas with intact thoracolumbar spines were dissected. Results: Nine pairs of posterior intercostal arteries, one pair of subcostal arteries, and four pairs of lumbar arteries, were examined in detail. The origin of the posterior intercostal arteries at the upper thoracic level was situated at most about two levels caudal to the feeding level, while those at the lower levels were just caudal to the corresponding feeding levels. The position of the bilateral orifices of the SAs in the axial plane of the aorta was on the medial side at the thoracic levels, whereas it was on the dorsal side at the lumbar levels. The horizontal distance between the orifices in the lumen of the aorta was found to be wider at the thoracic than at the lumbar level, and the longitudinal distance was higher at the lower level, corresponding to the height of the vertebrae. Conclusion: Understanding of the three dimensional relations of the initial segment of the SAs with the aorta and vertebral column is necessary for rational performance of the examination by two-dimensional fluorescent display.

Infected Charcot Spine Yoshio SUDA, et al. We report two rare cases of infected Charcot spine following spinal cord injury. Case 1 was a 44-year old man who presented with a destructive lesion in the lumbo-sacral spine and a fistula in his back 7 years after a Th7 spinal cord injury. Case 2 was a 62-year old man who presented with an L3/4 destructive lesion and a fistula in his back 19 years after a Th10 spinal cord injury. Anterior bone graft, percutaneous external spinal fixation, and suction/irrigation of the wound was performed for these patients. In Case 1, primary closure of the fistula and complete bone fusion was achieved after the operation. In Case 2, absorption of the grafted bone occurred after removal of the external fixation. Infection of a Charcot spine, although a rare clinical entity, should be considered as a diagnostic possibility in spinal cord-injured patients. External spinal fixation is a useful method for an unstable spinal lesion with infection.

Postoperative Infection in Spinal Instrumentation Surgery Akiyoshi YAMAZAKI, et al. Six infected patients were enrolled for this study. Four MRSA patients out of 724(0.55%) had undergone instrumentation in our hospital and 2 patients in other hospitals. All patients had PLIF with cages and pedicle screws. The ages at the operation were below 70 years except for one 82-year-old female. Four patients were undernourished. DM, immunosuppression by steroid therapy and UTI were each seen in 1 patient. Duration of preoperative hospital stay was especially long in 2 patients. Op. time was more than 3 hours in 4 patients. Intraoperative blood loss was more than 500 g in 3 patients. Multilevel fusions were carried out in 2 patients. Four patients were not operated in the bio-clean room. MRSA infection was more severe than MRSE infection. In all patients instruments were removed and debridement was carried out 2.3 times on the average, followed by continuous irrigation, which was effective enough to cure infection in 4 patients. Cages were removed in 3 patients. However, they were sometimes left in place if unaffected by infection. CRP became negative in 8.2 months on the average except for one patinet. Bony fusion was accomplished in 4 patients.

 

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