Surgical Technique for Spine and Spinal Nerves
Vol.9 No.1(2007)

Main Theme 1: Spinal Instrumentation at Lumbosacral Junction
A Modified Technique of Intrasacral Rod Fixation(Jackson)by Using Iliac Screw
Yoichi AOTA, et al.
Abstract 　Purpose: In an attempt to widen the surgical indication of Jackson sacral fixation technique, a modified method using an iliac screw was developed.
Materials & Methods: Intrasacral rods were inserted through an iliac screw in two patients in whom the S1 pedicle screw could not be used. One was a case of tuberculous spondylitis in the sacrum, in whom the S1 vertebral body wad destroyed.
The other case was lumbosacral scoliosis due to neurofibromatosis Type I, in whom the left S1 pedicle was highly attenuated.
Results: Post-surgical courses were uneventful. Solid bone fusion was achieved in both patients.
Conclusion: The modified Jackson technique using an iliac screw was proved to be a feasible and effective technique when S1 pedicle screws cannot be used.
Bony Fusion after Multi-Level Lumbar Fusion Including the Sacrum
Akiyoshi YAMAZAKI, et al.
Sixty-six patients who had multi-level lumbar fusion including the sacrum were enrolled in this study. The number of fusion levels averaged 2.7 segments. PLIF was performed in 59 patients. Cages and local-bone were used. All the instruments were pedicle screw systems, including Colorado II(ala screw) in 12 patients and Liberty(intrasacral rod) in 4. The patients were separated into 3 groups according to the number of S1 pedicle screws penetrating the anterior cortex, judged by postoperative CT as follows; 0 screw in 19 patients, 1 screw in 12 and 2 screws in 35. The overall fusion rate was 70%, and it decreased as the number of fusion segments increased. Especially at L5/S and at the most cranial levels, fusion was difficult.
The fusion rate at L5/S was significantly high, with both S1 screws penetrating the anterior cortex. Moreover, all 12 patients with Colorado II and 3 out of 4 patients with Liberty showed fusion at L5/S, which proved that both systems were useful to stabilize L5/S. However, as the fusion rate at L5/S increased, that at the most cranial level inversely decreased.
Main Theme 2: Operative Treatment of Spinal Infection
A Case of Posterior Lumbar Shortening Osteotomy for Lumbar Kyphosis Accompanying Tuberculous Spondylitis
Toru OSAWA, et al.
We successfully treated lumbar kyphosis associated with tuberculous spondylitis in a 77-year-old man by lumbar shortening osteotomy. He had complained of low back and leg pain, and infectious tuberculous spondylitis at L3 was suspected at his first presentation. Anti-tuberculosis treatment was initiated, and posterior decompression for the lumbar vertebrae was performed for alleviation of the nervous manifestations. Wedge deformity and backward curvature of the lumbar vertebrae gradually progressed, low back pain increased, and walking became difficult. Surgery was performed again. After intervertebral curettage in the affected area and cuneiform osteotomy of the vertebral body according to Kokubun's method, the spine was shortened and fixed with a pedicle screw. The patient became capable of independent ambulation postoperatively, and back pain disappeared. Six months after surgery, there was no recurrence of infection, and the correction was still maintained. In our lumbar shortening osteotomy, both curettage of the site of infection and correction of the backward curvature could be done simultaneously, without any complications of autogenous bone graft. This procedure therefore seems an excellent surgical option for lumbar kyphosis associated with tuberculous spondylitis.
Surgical Treatment Using Posterior Instrumentation with Pedicle Screws for Infectious Spondylitis in Thoraco-Lumbar Spine
Akira SAITO, et al.
12 patients with infectious spondylitis in thoraco-lumbar spine(TLS) treated by posterior instrumentation(PI) with pedicle screw were reviewed. There were 6 males and 6 females, with an average age of 68 years. The average duration of follow up was 48 months. Clinical diagnosis involved 6 cases with pyogenic spondylitis, 4 with tuberculous spondylitis, one with mycetogenic spondylitis and 1 undiagnosed. We evaluated the kyphotic angle in the region of infection before and after operation. There was one case with loss of correction of 5 degrees in the thoracic spine but no cases with loss of correction in the thoraco-lumbar spine. Failure of instruments was seen in two cases, with breakage of one pedicle screw. Each these showed no neurological deficit. In PI for infectious spondylitis in TLS, application of the pedicle screw produced good correction of kyphotic deformity and good maintenance. We think PI using a pedicle screw for infectious spondylitis in TLS is a good method and useful in obtaining correction of kyphotic deformities and early postoperative rehabilitation.
Treatment for Deep Wound Infection after Instrumented Spinal Surgery with Antibiotic-Impregnated Methylmethacrylate Wrap around Implants
-Report of 4 Cases-
Takahiro HOZUMI, et al.
We report 4 cases of early deep wound infection after instrumented spinal surgery that were successfully managed by wrapping implants in antibiotic-impregnated methylmethacrylate(PMMA). After debridement, the implants were wrapped in a 40 g bag of PMMA containing vancomycin(3 g), and primary closure over drains was performed for postoperative MRCNS infection. The patients were treated with intravenous antibiotics for 6 weeks, and were then placed on oral antibiotics. The wound healed uneventfully in 3 cases. Wound dehiscence occurred due to radiational skin disorder in one case.
Although the overall results of repeated debridement have been encouraging, it requires multiple procedures. Antibioticimpregnated PMMA beads have been reported as an available option, because this method requires only a single procedure, but the results in the literature have been unsatisfactory. Our present procedure is believed to improve the delivery of antibiotics to bacterial biofilms around implants, compared to the use of PMMA beads.
Postoperative Surgical Site Infection in Spinal Instrumentation
Shuntaro TSUCHIDA, et al.
The purpose of this presentation is to study retrospectively postoperative surgical site infection after spinal instrumentation in our hospital
［Materials and Methods］1083 spine surgeries were performed in our hospital during the last three years(Apr. 2004 to Mar. 2006). Among these operations were 385 spinal instrumentations. Nine operations were complicated with infection(2.3%).
The risk factors of patient(age, associated disease, smoking, nutritional condition) and those of operation(diagnosis, surgery, operation time, blood loss, causative bacteria) and the management of infection were studied.
［Results］One patient was over 80 years old at operation. DM and poor nutritional condition were seen in one patient. Four had the smoking habit. Three had multiple previous surgery. Two had malignant disease. Infections were noted from 8 days to 11 weeks after operation. Debridement and primary closure were done in all cases. Instruments were removed from 4 of 9 patients. Leaving the wound open and delayed closure was needed in one case. Hyperbaric oxygen therapy was applied in 4. MRSA was found in 4. Postoperative MRI evaluation for fluid collection was done in all cases.
［Conclusion］Our current principles for postoperative surgical site infection after spinal instrumentation were: 1. Preoperative informed consent by the patient about possible postoperative infection; 2. MRI to detect abscess; 3. Early wound aspiration; 4. Early institution of debridement; 5. Early administration of MRSA drugs; 6. Early institution of hyperbaric oxygen therapy; 7. Primary closure without removal of implant and continuous irrigation.
Main Theme 3: Minimally Invasive Spinal Surgery
Clinical Outcomes Using Microendoscopic Discectomy for Lumbar Disc Herniation at L4／5 Compared with L5／S1
Kimiaki SATO, et al.
［Purpose］To compare the clinical outcomes of microendoscopic discectomy(MED) for lumbar disc herniation(LDH) at L4/5 with those at L5/S1.
［Materials and Methods］The clinical outcomes were reviewed in all 40 consecutive patients treated using MED for singlelevel LDH at L4/5 or L5/S1. The L4/5 Group consisted of 21 patients(12 male and 9 female), with an average age at operation of 33.3 years, and average follow-up of 12.9 months. The L5/S1 Group consisted of 19 patients(13 male and 6 female), with an average age at operation of 33.5 years, and average follow-up of 9.9 months. The surgical outcomes were compared between the two groups on the basis of operative duration, blood loss, total of times of analgesics administered, period until initial walking, patient-based outcomes using the Visual Analogue Scale(VAS), and the Roland-Morris Disability Questionnaire(RDQ).
［Results］There was no significant difference between the two groups in operative duration, blood loss, total of times of analgesics administered, period until initial walking, or in patient-based outcomes using the VAS and the deviation value of RDQ.
［Conclusion］The clinical outcomes achieved using MED for LDH at L4/5 were similar to those obtained at L5/S1.
Unilateral Microdecompression for Lumbar Spinal Canal Stenosis
Yuichiro NISHIJIMA
The purpose of this report is to present microscopic decompression through unilateral approach in patients with lumbar spinal canal stenosis.
[Methods] One side of the paraspinal muscle was divided through a 2 cm posterior midline incision. The lateral half of the spinal process was removed. A hypertrophied yellow ligament was released form its laminar attachments at both rostral and caudal lamina edges. Detaching the yellow ligament from the lamina at one stage enabled a safe decompression of neural tissue. By changing the light axis of the microscope, it was possible to remove the yellow ligament of the opposite side.
[Patients] We directly followed 321 patients for at least 6 months(22.9 months in average). The mean age was 66.7 y.. Preoperative JOA score was 15.9/29 in average. Patient-based outcomes were evaluated with SF36. Preoperative X-rays showed some instability in 250(78%) patients, including forward slipping, backward slipping, scoliosis and rotational instability.
[Results] Preoperative 15.9 points of JOA score were improved to 21.9 points postoperatively. Seven of 8 Lower scales in SF36 were significantly improved. There were no statistical differences between the results in patients having shown instability and those having shown none. The post operative slip angle and percent slip did not change statistically.
[Conclusion] A better prognosis was obtained with this technique even in patients with lumbar instability on X-ray.
Clinical Results of Microendoscopic Decompression for Degenerative Lumbar Scoliosis
Kazuhiro MAIO, et al.
Purpose: For several years, we have treated lumbar canal stenosis by microendoscopic decompression. The purpose of this report is to evaluate the clinical results of microendoscopic decompression for degenerative lumbar scoliosis.
Material and Methods: 26 patients(average age 68.2 years) underwent microendoscopic decompression for degenerative lumbar scoliosis. The follow-up period was 15.3 months. We investigated the Japanese Orthopaedic Association(JOA) score for low back pain, re-operation, and the Cobb angle.
Results: The average JOA score improved from preoperative 13.0 to postoperative 22.5. The average Cobb angles before and after operation were 19.7°a nd 22.6°, respectively. Most cases got better for low back pain, but one case got worse. Four cases required re-operation. Epidural hematoma occurred in one case and three cases needed spinal fusion with instrumentation.
Discussion: This report showed that microendoscopic decompression is useful and the instability did not progress even in the case who had been said to need fixation surgery. However, it was impossible to deal with all conditions of degenerative lumbar scoliosis even with microendoscopic decompression.
Conclusion: We studied the clinical results of microendoscopic decompression for degenerative lumbar scoliosis. The clinical results were good, but a long term follow-up will be needed.
Microendoscopic Surgery for Lumbar Radiculopathy Concomitant with Lumbosacral Nerve Root Anomaly
Yukihiro NAKAGAWA, et al.
Purpose: The aim of this study is to report the results of posterior microendoscopic surgery for lumbosacral nerve root anomalies.
Patients and methods: Eight patients with lumbosacral nerve root anomalies underwent posterior microendoscopic surgery. Lumbar disc herniation was present in six cases, and spinal stenosis in two. Clinical results, perioperative complications, affected site and type of nerve root anomaly were investigated.
Results: According to McCulloch's classification, patients were divied into six conjoined nerve roots and two transverse nerve roots. Conjoined nerve roots were located in L5-S1 in five cases and S1-S2 in one case. Seven cases could be operated successfully with microendoscopic technique. One case of transverse nerve root needed an open conversion because of dural laceration. Except in this case, there was no complication. All cases improved after surgery.
Conclusion: The microendoscopic technique can be applied for decompression of nerve root anomalies. These anomalies are frequently unrecognized in advanced imaging studies, which accounts for some failed spinal surgical procedures. Preoperative identification of the nerve root anomalies allows their existence to be considered in the surgical plan.
Microendoscopic Decompression Procedure via Interlaminar Midline Approach for Lumbar Spinal Canal Stenosis
-Operative Procedure to Obtain Good Clinical Results-
Masateru NAGAE, et al.
We devised a new microendoscopic surgical procedure through by interlaminar midline approach(Microendoscopic Muscle-preserving Midline Interspinous Interlaminar Decompression: ME-MILD), which has been performed for central type lumbar spinal canal stenosis. We have reviewed the short-term results of ME-MILD, and problems of the operative procedure. The subjects were 32 patients with central type lumbar spinal canal stenosis. The mean age was 68.0 years, and the mean postoperative follow-up period was 11.4 months. We investigated the operation time, operative blood loss, JOA score and complications. The mean operation time was 112.9 minutes per level, and the operative blood loss was 54.6 g. The mean JOA score before the operation was 14.8 points, which improved to 25.6 points after the operation. We experienced one case of dural tear and one of transient postoperative muscle weakness.
ME-MILD brings a wide and well-orientated visual field without damaging paravertebral muscles or facet joints. By tipping the tubular retractor in all directions, manipulation for nerve roots and intervertebral disc is possible. The preservation of posterior stabilizing elements is ensured by sewing up the bilaterally-divided periost of the spinous process and the supra/interspinous ligament in the midline. ME-MILD is a useful and less invasive decompression procedure for lumbar spinal canal stenosis.
MIS-PLIF by X-Tube and SEXTANT System
Koji SATO, et al.
We used an X-tube retractor from 2003 and with one side approach did decompression of both sides and PLIF. Furthermore, the pair side used the SEXTANT system by which we could insert PS and a rod percutaneously without much change since October, 2005. The cases that underwernt MIS-PLIF by X-tube and SEXTANT since October, 2005 are 35 in number. One side approach, both sides decompression. The pair side inserts percutaneous PS and a rod in the SEXTANT system. We do interbody fixation with a cage. The average blood loss and operation time for one intervertebral are 117 g and 124 minutes, for two intervertebrals 108 g and 160 minutes. Implant failures occurred in 2 cases of PS; a rod could not be inserted, and it made a small open wound when a point of a guide pin was broken. Dural injury occurred in 3 cases, extradural haematoma in one case. It was in installation and the handling of the screw head that attention was necessary in the manual use of SEXTANT. Because we do it percutaneously with a small field, this maneuver requires scrupulous attention. We have SEXTANT and know the directions for use well enough to use it.
MIS-TLIF Using X-Tube and SEXTANT
Keisuke NAKANO
Purpose: We report 10 cases of pedicle screw fixation using virtual fluoroscopy and SEXTANTTM.
Materials & Methods: Ten patients(5 men and 5 women), who ranged in age from 13 to 83 years were included in this study. Causative disease included tuberculous spondylitis in 1 case, metastatic tumor in 1, lumbar ptosis in 1, spondylolisthesis in 2, spondylolysis in 1, lumbar spinal canal stenosis in 2, lumbar disc herniation in 1 and burst fracture in 1. A computerassisted pedicle screw fixation was performed with SEXTANTTM under virtual fluoroscopy with STEALTHSTATION TREON plusTM and Fluoro Nav Spine ApplicationTM. A dynamic reference arc was attached at the spinous process concerned. Serial AP, lateral, and bilateral oblique images were obtained with a C-arm. The screw entry point was explored in 7 patients; screws were inserted without any exploration in 3. The position of the screw in the pedicle was analyzed by postoperative axial CT.
Results: A total of 46 screws were inserted and 10 were removed during or after surgery because of possible malposition.
The remaining 36 screws were included for analysis. Screws with breach less than 2 mm or no breach were 91.6%. Three rods failed to connect with screws transcutaneously and needed exploration of lamina for rod connection. No complication during this procedure occurred in any of the cases.
Discussion: Standard techniques for pedicle screw placement require extensive tissue dissection. Percutaneous screwing and rod fixation can minimize exploration. However, careful use of navigation and SEXTANTTM system are needed.
Results of Pedicle Screw and Rod Fixation by Using SEXTANTTM under Virtual Fluoroscopy
-A Preliminary Report-
Masaaki UESUGI, et al.
Purpose: We report 10 cases of pedicle screw fixation using virtual fluoroscopy and SEXTANTTM.
Materials & Methods: Ten patients(5 men and 5 women), who ranged in age from 13 to 83 years were included in this study. Causative disease included tuberculous spondylitis in 1 case, metastatic tumor in 1, lumbar ptosis in 1, spondylolisthesis in 2, spondylolysis in 1, lumbar spinal canal stenosis in 2, lumbar disc herniation in 1 and burst fracture in 1. A computerassisted pedicle screw fixation was performed with SEXTANTTM under virtual fluoroscopy with STEALTHSTATION TREON plusTM and Fluoro Nav Spine ApplicationTM. A dynamic reference arc was attached at the spinous process concerned. Serial AP, lateral, and bilateral oblique images were obtained with a C-arm. The screw entry point was explored in 7 patients; screws were inserted without any exploration in 3. The position of the screw in the pedicle was analyzed by postoperative axial CT.
Results: A total of 46 screws were inserted and 10 were removed during or after surgery because of possible malposition.
The remaining 36 screws were included for analysis. Screws with breach less than 2 mm or no breach were 91.6%. Three rods failed to connect with screws transcutaneously and needed exploration of lamina for rod connection. No complication during this procedure occurred in any of the cases.
Discussion: Standard techniques for pedicle screw placement require extensive tissue dissection. Percutaneous screwing and rod fixation can minimize exploration. However, careful use of navigation and SEXTANTTM system are needed.
Less Invasive PLIF with Sextant and Unilateral Approach, Bilateral Decompression Technique
Takahiro SANADA, et al.
We performed a less invasive PLIF with unilateral approach, bilateral decompression technique and Sextant. 1- level PLIF was performed in 8 patients for degenerative spondylolisthesis, isthmic listhesis, and discogenic pain. A 4-5 cm midline incision was made, the spinous process was cut transversely and retracted towards the contralateral side. Decompression and PLIF were done, and pedicle screw and rod fixation with Sextant was then performed.
Pedicle screw and rod fixation was easily and successfully done in all cases. Mean blood loss was 131 g. Mean operation time was 240 min. There was a trend towards less intraoperative blood loss and postoperative low back pain.
Minimally invasive PLIF with a tubular retractor has been reported. Its disadvantages were the small operative field, learning curve, and poor visibility of the operative field to the assistant. Because of these disadvantages, MIS-PLIF with a tubular retractor has not been widely accepted. In our method, both operator and assistant are able to share good visibility. This method is less invasive in terms of blood loss and postoperative low back pain than open standard surgery and paraspinal approach using an X-tube.
Clinical Results of Computer Navigation-Assisted Minimally Invasive TLIF(MIS-TLIF)
Takuya FUJITA, et al.
[Purpose] We have been performing minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF) using a CD HORIZON SEXTANT system with a computer navigation system for lumbar degenerative spondylolisthesis. The aim of this study was to assess the short-term clinical results of this procedure.
[Surgical procedure] A 25-mm longitudinal incision was made over the appropriate decompression level. Bilateral decompression was performed using a surgical microscope. Following this, pedicle screws and a rod were percutaneously placed on the opposite side, using a computer navigation system. Following this, a cage was inserted from the approach side, and pedicle screws and rod were placed on the approach side in the same manner.
[Materials and methods] Eight patients with degenerative spondylolisthesis underwent this procedure upto May 2006. Clinical results were evaluated by 1) operative time, 2) estimated blood loss, 3) JOA score, and 4) radiological evaluation by T2WI on MRI.
[Results] All patinents'symptoms resolved immediately just after surgery. The average pre-JOA score was 16.9 points, whereas the post-op. score was 23.9 points with a recovery rate of 56.9%, representing good clinical results. The average operative time was 290 minutes and blood loss was 213 ml. Signal changes of the paraspinal muscle on MRI in patients with MIS-TLIF were much less than those with PLIF, especially on the opposite side.
[Discussion and Conclusion] MIS-TLIF with a computer navigation system provided good results and low invasiveness, but the preparation and adjustment of the computer navigation system led to prolongation of operative time.
Outcomes of Less Invasive PLIF Using Interbody Spacer and Local Bones for Degenerative Lumbar Spondylolisthesis
-Graft Subsidence and Bony Fusion-
Futoshi SUETSUNA, et al.
We present the radiographic and clinical outcomes of PLIF using interbody spacers and only local bones. 44 patients with L4 degenerative spondylolisthesis were reviewed. The average follow-up period was 5.0 years. There were 9 men and 35 women with an average age of 65.7 years. Radiographic parameters included fusion rate, subsidence of the spacers, slip angle and %slip. Clinical parameters included recovery rate using the JOA score. Subsidence of the spacers was evaluated using the ratio of the height of L4/5 inter-vertebral space to the height of L4 vertebral body. The fusion rate was 100%.
The average pre and postoperative and latest follow-up %slip were 17.0%, 7.8% and 7.7%. The average pre- and postoperative and latest follow-up slip angles were 2 degrees, －10.6 degrees and －10.7 degrees. The average pre- and postoperative and latest follow-up ratios of the subsidence were 0.31, 0.44 and 0.44. Recovery rate was 80.0%. Our PLIF needs a smaller size of spacers than that of cages and no twist motion to insert graft materials. Our PLIF method is a simple and less invasive method that produces excellent radiographic and clinical outcomes without sacrifice of iliac bones.
The Learning Curve of Muscle-Preserving Interlaminar Decompression of Lumbar Spine(MILD)
Tomohisa HARADA, et al.
The aim of this study is to evaluate the learning curve of a new procedure(muscle preserving interlaminar decompression: MILD) for lumbar spinal canal stenosis. The subjects were the initial 36 consecutive patients with LSCS operated by two surgeons A and B(18 cases each). There were 13 males and 23 females, and the mean age was 71.3 years. The average postoperative follow-up period was 13.3 months. Cases were divided into six groups according to the surgeon and the operation stage(earlier, medium and later term), and we analyzed the operation time, estimated blood loss, mean recovery rate by JOA score, and complications in each group. The mean operation time and blood loss per level were 101 minutes and 38 g respectively, and the mean recovery rate by JOA score was 61.5%. Dural tear occurred in only one case. There was no significant difference in operation time on blood loss between each of the groups. The interspinous midline approach contributed to the symmetric operative field and less invasion of the paravertebral muscles. The advantage of MILD is low blood loss and an operative field with good orientation for the surgeon. In fact, the learning curve of MILD is gradual.
Muscle-Preserving Interlaminar Decompression(MILD)for the Treatment of Lumbar Spinal Canal Stenosis Combined with Lumbar Disc Herniation
Naoki OKUBO, et al.
We have reported the clinical results of muscle-preserving interlaminar decompression(MILD) which we developed as a minimally invasive form of surgery for lumbar spinal canal stenosis(LSCS). The purpose of this study is to investigate the short-term results of MILD applied to LSCS combined with lumbar disc herniation.
The subjects were 9 patients(4 male and 5 female) with a mean age of 67.2 years. The surgery was performed using a surgical microscope. Via midline interspinous approach, the spinous processes were partially drilled and supra- and interspinous ligaments were divided longitudinally to extend the operative field. After sufficient resection of the caudal, cranial, and lateral edges of the lamina and total resection of the ligamentum flavum, the discectomy was performed in the same operative field with slight retraction of the nerve root. The mean operation time was 118.6 minutes per level, and the mean amount of surgical blood loss was 34.1 g per level. The mean JOA score was 9.8 points before surgery, which improved to 22.9 points after surgery.
The advantages of MILD are the minimal invasion of the paravertebral muscles, and the preservation of the facet joints and spinous processes as lever arms. This method would be useful for the treatment of LSCS combined with lumbar disc herniation.
A New Decompression Method for Lumbar Spinal Canal Stenosis Using a Technique of Figure Eight Reattachment of Split Spinous Process
Yoichi JIN, et al.
Purpose: We developed a new technique of figure eight reattachment of split spinous process in lumbar spinal canal stenosis. The purpose of this study is to describe this procedure and its short-term results.
Materials: The subjects were 33 patients(17 male and 16 female). The average age was 73.3 years, and the average period of postoperative follow-up was 5.1 months. A total of 44 levels were decompressed.
Methods: After skin incision, the supraspinous and interspinous ligaments were cut longitudinally with a scalpel at the midline. The spinous process was split with an osteotome. After decompression was finished, the split spinous processes were sewed up with their base.
Results: The mean operation time was 120 minutes per level, and mean blood loss was 89 ml per level. The average period for sitting was 1.0 days, for walking 1.6 days and for hospitalization 12.0 days after operation. The mean recovery rate by the JOA score was 80.3%. The mean length of skin incision at L4/5 was 2.9 cm.
Discussion: The problems of bilateral microendoscopic decompression by unilateral approach are that the preservation of the facet on the approach side is difficult and the learning curve is steep. The advantages of this method are small skin incision, preservation of ligaments and paravertebral muscles, good orientation and wide operative view, easy decompression of the lateral recess from the other side, and preservation of the lever arm of the extension mechanism.
Conclusion: This method does not need special equipment, is minimally invasive and offers precise decompression. The short-term results were excellent.
Yellow Ligament Floating Method for Lumbar Spinal Canal Stenosis
-Minimum Invasive Surgery for Nerve-
Takashi YAMAZAKI, et al.
We developed a novel decompression technique for lumbar spinal canal stenosis, which just floated the yellow ligament. This technique can preserve the epidural vessel plexus or fat and may reduce adhesion of the cauda equina or postoperative scar tissue formation. The short-term clinical result was good, and the occurrence of incidental durotomy decreased.
Although, the long term clinical results and the fate of the floated yellow ligament are not yet known, this technique was useful in decompression for lumbar canal stenosis because of the minimal invasion of the nerve and the safety.
Less invasive removal of extradural arachnoid cyst in the thoracic spine:technical note
Kunihiko SASAI, et al.
The authors introduced a new surgical technique for less invasively removal of a cyst. A 43-year-old man complained of dropped foot on the left side. MRI showed an extradural arachnoid cyst from Th11 to L1, and the conus medullary was compressed at the same level. The communicating hole was not detected by preoperative imaging. Microsurgical hemilaminectomy of Th12 only was performed with spinal cord monitoring. The approximately 5 mm communication hole was found, and this was sutured after the dorsal aspect of the cyst had been incised. After parts of the cyst had been removed, the edges of both the cranial and the caudal sides were held and pulled away, by peeling the adhesion between the ventral wall of the cyst and the dura on the dorsal side. Finally, the cyst wall was completely removed. At the present time, 2 years postoperatively, the dropped foot has improved and MRI shows no recurrence of the cyst. Regarding the surgical treatment of extradural arachnoid cyst, it is generally important to detect the communication hole before operation. A few authors have found the communicating hole by using MRI or spinal scope. However, we could remove the cyst completely and safely, using our surgical method, even though the communicating hole was not detected preoperatively.
Improvement of Alignment by Combined Use of a Percutaneous Vertebroplasty and a Lumbar Laminectomy for Lumbar Spinal Scoliosis
－A Case Report－
Nobuhiro SASAKI, et al.
[Introduction] When performing lumbar laminectomy on patients who have scoliosis or any other instability, combined use of fixation surgery is often needed to prevent aggravation of alignment. However, fixation surgery is very invasive and, often causes severe postoperative back pain. We combined a percutaneous vertebroplasty and a lumbar laminectomy for such a patient, and obtained not only improvement of neurological symptoms but also improvement of scoliosis which was noted before the operation.
[Case] The case was a 78 year-old woman. Pain in the left lower limb had appeared about 4 years before. She had had a lumbar discectomy for left L4/5 disc herniation at another hospital. The scoliosis that existed before the operation turned worse. As for her height, it decreased by 4 centimeters in four years. She then had a checkup in our hospital because she suffered aggravation of neurological deficits. After obtaining informed consent, we performed a percutaneous vertebroplasty for the purpose of prevention of progress of scoliosis. After operation, the neurological deficits were very much improved and the scoliosis was improved on X-ray even more.
[Consideration] Although the mechanism of alignment improvement is not clear, it is speculated that it may be an effect of the increase in height of vertebral bodies by injection of bone cement and exfoliation of adhesions around a spinal joint, etc.
[Conclusion] This being the report of only one case, it is not sufficient experience. However, if the validity of this method can be checked, we can treat such patients by a less invasive and better procedure than the conventional method.
Percutaneous Vertebroplasty -Our Technique and Results-
Toru KOIZUMI, et al.
[Purpose] Percutaneous vertebroplasty is a new method for compression fractures, and many reports have shown good results. We report our method and results.
[Clinical Cases] We started vertebroplasty from December 2004, and treated 137 cases(total 162 procedures) up to December 2006. Ages were 21-92 years(average 74.2 years old), 44 men and 93 women. The number of treated vertebral bodies in one procedure was 1-4(average 1.59).
[Result] We used a PMMA injection method. It was possible to use local anesthesia, except for one case which required laminectomy. There were no complications, such as lung embolism or neurological symptoms. 97.5% of patients reported improvement of severe back pain. 77.8% obtained almost complete pain relief.
[Conclusion] In our experience, percutaneous vertebroplasty is a safe, less invasive and effective medical treatment for achieving pain relief. Vertebroplasty will improve the outcome of compression fractures.
Development of a New Operation Instruments for"K-Method”Cervical Laminoplasty
Shun-ichi KIHARA, et al.
[Purpose] We developed a new open door cervical laminoplasty using a spinoplastic hydroxyapatite spacer(Kspacer), and reported it as"K-method”. More than 1000 patients have already undergone this surgery and no analgesics for postoperative nuchal pains have been required in almost all cases. We developed a new operation instrument for the"Kmethod” cervical laminoplasty.
[K-method] We have already reported the details of the technique of the K-method. Our method was a minimally invasive procedure with a skin incision of only 3 cm.
[Operation instrument] In order to perform an operation in a narrow surgical field, good retraction is very important for the success of the procedure. We therefore developed more than thirty kinds of retractors. Our newly developed skin hook does not damage the edge of the skin incision.
[Conclusion] Using our newly developed operation instruments, the K-method will be safer and simpler. We intend to develop more useful materials and instruments for K-method laminoplasty.
Minimally Invasive Cervical Laminoplasty(K-Method)
-148 Cases of Own Experience-
Takeshi UMEBAYASHI, et al.
(Purpose) We developed open-door cervical laminoplasty using a spinoplastic hydorxy apatite spacer(K-method), and obtained good results. We report the first author's 148 consecutive cases, and discuss the short-term operation results.
(Materials and methods) From September 2004 to September 2006, the first author operated on 148 cases(males 104, females 44, mean ages 59.4 years). The diagnoses of the 148 cases are as follows; cervical spondylosis 94, developmental cervical canal stenosis 36, OPLL 13, cervical disc herniation 7. We evaluated the pre- and postoperative JOA score and Hirabayashi's method, and reviewed neurological symptoms, operation time and bleeding.
(Results) Preoperative JOA score was 10.3±2.5, and postoperative 14.5±3.3.
Around 4.8% suffered transient postoperative C5 palsy. Operation time, and volume of bleeding decreased with accumulation of cases.
(Conclusion) The K-method is a very useful technique. However, good practice is required to understand the principles and practice of the method
Minimally Invasive Cervical Expansive Open-Door Laminoplasty(K-method)for Patients with Cervical Myelopathy Due to
Ossification of the Posterior Longitudinal Ligament
-Clinical and Radiological Review-
Keishi TSUNODA, et al.
[Purpose] The surgical treatment for patients with cervical myelopathy due to ossification of the posterior longitudinal ligament includes either anterior approach or posterior approach. Open-door laminoplasty with Kihara's spinoplastic hydroxyapatite spacer(K-method) is a minimally invasive method with a good clinical outcome. The purpose of this study is to establish the clinical outcome of the patients who underwent K-method laminoplasty in our centre and compare with others.
[Materials and Methods] Between February 2004 and January 2006, 66 patients underwent the K-method, of whom 14 had myelopathy due to ossification of the posterior longitudinal ligament. They consisted of 9 males and 5 females. Their ages ranged from 34 to 71 years(average 61.4). Clinical conditions, images, and treatment results were investigated.
[Results] The mean preoperative JOA score was 10.7±3.9 points(range 5.5～16), mean postoperative JOA score 15.4±1.7 points(range 12.5～17), and mean improvement rate 79.3%. There was no C5 palsy or any other complications. The mean occupying ratio of OPLL in CT axial image improved from 36.6±11.1%(range 16.8～54.9) preoperatively to 20.2±7.8%(range 7.8～36.5) postoperatively. A T2WI-MRI high intensity area was identified in 10 cases preoperatively, but none showed enlargement of this area postoperatively. The mean alignment of the cervical spine improved from 8.6±10.8°( range －10～31) preoperatively to 12.1±9.0°( range 0～31) postoperatively.
[Discussion and Conclusion] K-method is a very useful procedure for patients with cervical myelopathy due to ossification of the posterior longitudinal ligament, but long-term observation in the future is necessary.
Usefulness of Preoperative Dynamic MRI in Selective Laminoplasty
Atsuto SAKAMOTO, et al.
Selective laminoplasty has been performed for cervical spondylotic myelopathy(CSM) in our institutions. Preoperative
dynamic MRI was used to determine the decompression area of the selective laminoplasty.
The subjects were 41 patients with CSM, who had undergone preoperative dynamic MRI in flexion, neutral and extension positions. The changes in the number of intervertebral levels with cord compression(compression number) on images in each position were evaluated.
Patients were divided into two groups; the compression number increased in the extension position than the neutral position in group A, but did not change in group B. Decompression was performed for all intervertebral levels where cord compression was seen in either of the images.
Group A comprised 30 patients(73.2%). In this group A, the mean compression number had increased from 1.4 in the neutral position to 3.1 in the extension position, and the mean recovery rate was 54.9%. Group B comprised 11 patients(26.8%).
In this group, the mean compression number was 3.5 in both neutral and extension positions, and the mean recovery rate was 49.6%.
Less invasive surgeries that limit decompression levels have recently been
Postoperative MRI and Clinical Results in Selective Cervical Laminoplasty
Tomohisa HARADA, et al.
The aim of this study is to evaluate the relation between the amount of dural tube expansion after selective
laminoplasty and its surgical results. The subjects were 34 patients(20 males and 14 females) with CSM who underwent selective laminoplasty. The mean age at the time of operation was 65.6 years. For each patient, pre- and postoperative JOA scores were analysed, and the recovery rate was obtained. All patients had postoperative MRI taken 4 to 12 months after operation.
With sagittal T2-weighted images, we scrutinized any obliteration of the anterior or posterior subarachnoid space at each intervertebral. According to these MRI findings, the patients were classified into 4 groups, as follows; those with no obliteration of anterior or posterior subarachnoid space were included in Group A, those with obliteration of anterior subarachnoid space at either one of the levels in Group B, those with obliteration of the posterior subarachnoid space in Group C, and those with obliteration of both anterior and posterior subarachnoid spaces in Group D. The recovery rates in Group A, B, and C went beyond 50%. Satisfactory clinical results can be expected when postoperative MRI shows opening of either the anterior or posterior the subarachnoid space.
Less Invasive Transvertebral Approach for the Cervical Spinal Degenerative Diseas
Masahito HARA, et al.
Key-hole surgery for herniated cervical disc and cervical spondylosis by a transvertebral approach has been performed. This method is minimally invasive to the cervical spine because most of the disc material is preserved. Since 2000, 50 patients(36 men and 14 women) have undergone operation for cervical radiculopathies. Only 20 cases were strictly followed. Study parameters such as clinical results, cervical lordosis, range of motion of affected vertebral bodies, disc height, and change of postero-anterior displacement were examined. Postoperatively, clinical symptoms were rapidly relieved in all cases. The range of motion of the affected vertebrae, lordosis of the cervical spine and change of postero-anterior displacement were unchanged. The height of the disc space was significantly decreased one year after the operation. One of the causes of postoperative disc height decrease might be the natural course and another might be the removal of a large amount of intervertebral disc, since the height of the disc space significantly decreased at C5/6, but did not change at C6/7, where operation could be done without any removal of intervertebral disc material. Decompression by the transvertebral approach for cervical radiculopathies is thought to be less invasive, especially in the lower cervical spine.
Anterior Cervical Fixation Using METRx Quadrant System
Masafumi ARAKI, et al.
The METRx quadrant system was used for 9 cases of single level anterior cervical fixation(Quadrant group). A comparison was made in JOA score, time of surgery and blood loss with 7 cases treated by the traditional method(traditional group).
In the traditional group and Quadrant group, the average time of surgery was 185.6 minutes and 205.5 minutes, blood loss 135.1 ml and 81.3 ml, and recovery rate of JOA score 63.1% and 65.2% respectively. In anterior cervical fixation, there was no significant difference in surgical outcome between the two groups but blood loss tended to be less in the Quadrant group than in the traditional group.
The METRx quadrant system uses an expanding retractor with a light. It gives a wider operative field through a smaller skin incision, and the length of the skin incision can be adjustable for each case. An illumination guide illuminates the smaller operative field, makes every detail visible, and assures safer and easier operative procedures.
This system is a less invasive method than the traditional method and is useful for anterior cervical fixation surgery.
Main Theme 4: Operative Treatment of Intramedullary Vascular Lesions
Surgery for Thoracic Vertebral Aggressive Hemangioma
-Case Report-
Naoki ASAMI, et al.
Purpose: A case report: Aggressive thoracic vertebral hemangioma which was treated with posterior decompression and posterior lateral fusion.
Materials & Methods: 57 year-old-male. Incidentally diagnosed during hepatic tumor examination. No neurological symptoms. Coarse trabeculated mass at T11 vertebral body infiltrated into the spinal canal, lamina and spinous process.
Results: After insertion of two above and two below pedicle screws, wide laminetomy of T11 was completed. Hemostasis was difficult but successful with bone wax and electric knife coagulation. The patient was discharged without complication.
Discussion and Conclusion: Some papers have been published reporting that aggressive hemangioma results in compression fracture and cord compression. This case was treated successfully, but needed preoperative embolization.
A Case of Idiopathic Thoracic Spinal Subarachnoid Hematoma
Hironobu YAMADA, et al.
The patient was a 55-year-old female with no particular past history. At 2 a.m. on October 21, 2005, she suddenly felt back and chest pain and was admitted to another hospital. By 4 a.m. she had pain in the lower back and the right lower extremity, and progressive motor weakness of both lower extremities. She was admitted to our hospital the next day. The neurological condition on admission was Frankel's grade B: complete paralysis, retention of urine, and hypoesthesic sensation below the level of T4 with right dominance. Deep tendon reflexes were hypoactive and Babinski reflex was positive. Routine laboratory data, prothrombin time and partial thromboplastin time were within normal limits. MRI revealed an intra-spinal canal space occupying lesion(SOL) from T4 to T6. The SOL showed low intensity on T1-weighted image and hypointensity on T2-weighted image. At 9 p.m. on October 22, laminectomy was performed at T4-6. When the dura was opened, clotted and dark liquid blood was seen through the arachnoid. When the arachnoid was opened, the clotted blood was evacuated. The spinal cord was displaced anteriorly. After removal of the subarachnoid hematoma, bleeding from the right T4 radicular artery was observed. Six months after surgery, the neurological condition improved to Frankel's grade C. In conclusion, an early decompression procedure is recommended to obtain good recovery of neurological function.
Reasoning about the Origin of Spontaneous Spinal Epidural Hemorrhage
-3 Cases Report-
Hiroyuki OHNARI, et al.
Spontaneous spinal epidural hemorrhage(SSEH) is a rare entity. Sudden onset and progressive neurological deterioration often require decompression of the spinal cord as an emergency. No case report could show the origin of SSEH, though prompt surgery was performed. Our 3 cases were suddenly attacked by severe pain, serious paralysis and vesicorectal dysfunction. Pre-operative MRI examination showed a hemorrhage which extended for 2 or 3 vertebral columns in the dorsolateral epidural space in each case. The origin could not be detected by posterior decompression surgery.
There was a convincing hypothesis that some event which induced pleural or endoceliac high pressure might trigger bleeding from the damaged epidural venous plexus which lacks of venous valves. Moreover, the hemorrhages were situated posteriorly in almost all cases, which supported that SSEH originates from the posterior epidural venous plexus.
If this is so, a laminectomy which excised all the posterior elements could remove the cause. In one of our cases, screening computed tomography was performed by plain and contrast medium. A white dot in the spinal canal corresponding to the SSEH in MRI was depicted by contrast medium. It was suspected that this white dot indicated hemorrhage, but we could not deny the possibility that key vessels of SSEH.
An Operative Case of the Cervical Intramedullary Cavernous Angioma with Symptomatic Hemorrhage
Keiichi AKATSUKA, et al.
A case with cervical intramedullary cavernous angioma showing symptomatic hemorrhage which was removed successfully is presented.
A twenty-five-year-old male felt a sudden weakness of the left upper extremity. Neurological examination showed monoparesis of the left upper extremity, mild pain sensory disturbance of the right upper extremity, and hyperreflexia of the left triceps muscle and both lower extremities. MRI revealed iso and partially high intensity areas in the enlarged cord on the T1 weighted image and a high intensity mass with low intensity rim on the T2 weighted image at C3-4 vertebral level. After conservative treatment for a month, surgical removal following. C2-4 mid-splitting laminotomy was performed. After splitting at the entry zone of the dorsal root, a dark reddish intramedullary mass was identified and removed piece by piece. Postoperatively, the patient showed left hemiparesis and sensory dissociation, but paresis of the left lower extremity recovered after a few days. Monoparesis of the left upper extremity has also gradually improved and now he has recovered full muscle power. He returned to his former job, although the sensory dissociation has remained.
Clinical Results of Surgical Interruption of Spinal Dural Arteriovenous Fistulas
Hiroshi TAKEI, et al.
Clinical results of 6 patients with spinal dural AVFs who underwent surgical interruption from 1998 to 2004 were reviewed. All patients were male aged 37-76 years, including 5 over 60 years. The average time between the onset of the initial symptoms and the operation was 18.2 months. The level of AVF was Th6 in 2 cases, Th7 in 1, L2 in 2, and L1 and L2 in 1 case. Previous lumbar decompression surgery had been done with misdiagnosis as lumbar spinal canal stenosis in 2 cases.
Embolization had been performed previously in 1 case resulting in insufficient interruption of the AVF. The AVFs and the draining veins were surgically interrupted in all cases with hemilaminoplasty in 2, recapping laminoplasty in 1, recapping hemilaminoplasty in 2, and extended laminectomy including facetectomy accompanied by PLF in 1 case. Preoperative JOA score was 4.1, postoperative score was 6, and recovery rate was 31.5% on average. The challenge for the optimum management of these patients was thought to be in making an early diagnosis and in definitive interruption of the AVFs and intradural draining vein with a less invasive prodecdure.
Two Cases of Thoraco-Lumbar Dural AVF
Eiichiro HONDA, et al.
There have been few subarachnoid hemorrhage in spinal dural AVF(spinal DAVF) in the thoraco-lumbar region, compared with morein acases involving the craniocervical joint. Thoraco-lumbar DAVFs always lead to bilateral motor function disorder in the lower limbs, with sensory disturbance, due to venous hypertension caused by A-V shunt. Spinal DAVFs often have a relentless, downhill course unless treated, and finally result in progressive vascular thrombosis and necrotic myelopathy. We report surgical intervention to spinal DAVFs in two cases.
Case 1: A 70-year-old woman presented with symptoms resembling intermittent claudication. This symptom began 4 years ago and included the fenestration of L4/5. MRI showed enlarged flow void in the dorsal spinal cord(like dot formation) between L1 and T12. However, no high intensity lesion in the spinal cord could be seen on T2WI. The draining vein was coagulated and cut. The symptom remained unchanged.
Case 2: A 61-year-old woman presented with poor elevation of the arm, weakness of lower limbs and grasping power and nuchal pain, developing within one year. A shunt was seen at T11/12 on angiography. During operation the obvious AV shunt could not be identified, because multiple shunts may be involved in spinal DAVF. Abnormal vessels in the multiple lesion were closed, with appearance of collapse in the abnormal veins.
Although the resulting obliteration was incomplete, the clinical effect indicated a good result.
Discussion: Both surgical interruption and endovascular therapy can be used to cure spinal DAVFs. Surgical interruption should be chosen first, in preference to simple shunt, because the operative procedure is easier, being coagulation and excision of the draining vein(radicular medullary vein). However, if the spinal DAVF is supplied by multiple feeders as in case 2, it is difficult to identify all feeders by angiography. For this reason the abnormal draining vein on the dorsal spine was coagulated and cut, while Doppler was used during the operation, which may be makeshift. Early diagnosis was needed, because long duration of illness would have caused severe neurological deficit. Enhanced MRI for evaluation of the poor outcome revealed preoperative spinal cord enhancement and prolonged postoperative cord enhancement.
Surgical Outcome of Spinal Dural Arteriovenous Fistulae
Minoru HOSHIMARU, et al.
(Purpose) Diagnosis of spinal dural arteriovenous fistula(SDAVF) is difficult because of the rarity of this disease and the similarities of MRI findings between SDAVF and intramedullary lesions. Clinical charts were reviewed to clarify any influence of delayed diagnosis on the surgical outcomes.
(Materials & Methods) Between 1983 and 2006, 20 patients with SDAVF were surgically treated at our hospital. The 3 women and 17 men had a mean age of 61 years(range, 41-78 years). At the time of admission, 7 patients had a provisional diagnosis of an intramedullary lesion. The average duration of symptoms before the correct diagnosis was 21 months(range, 3- 84 months). All patients had motor weakness and sensory disturbance of the lower extremities.
(Results) Dilated abnormal vessels connecting the fistula and veins running on the spinal cord were coagulated and cut. Symptoms were improved in 14 patients, remained unchanged in 5, and were worsened in 1 patient after surgery. The average duration of symptoms before the correct diagnosis was 16 months in patients showing neurological improvement after surgery, and 33 months in patients who did not show neurological improvement.
(Discussion and Conclusion) Early diagnosis and treatment are important to patients with this disease.
Surgery of Spinal Dural Arteriovenous Fistula -Removal of"Peloton”Followed by Drainer Occlusion-
Masanori ITO, et al.
[Purpose] To present the surgical procedures in a case with spinal dural arteriovenous fistula(SDAVF) in which the resection of a microscopic glomus of vessels,"pelotons”, was followed by division of the arterialized medullary draining vein as it entered the subarachnoid space.
[Materials and methods] We treated six cases with SDAVF: five endovascularly and one surgically. This case: A 66 year-old man was presented with progressive gait disturbance. Magnetic resonance imaging(MRI) revealed on intramedullary high intensity area with worm-like flow void area in the subarachnoid space on T2 weighted image. Spinal angiography showed perimedullary single coiled vessels that were fed by a radicular artery. We diagnosed a spinal dural arteriovenous fistula.
Operation: left hemilaminectomy was performed at T6, 7 and 8 levels. The dural arterial microvascular"pelotons”or whorls, a microscopic glomus of vessels, were first resected after small arterial feeders were divided. A midline dural incision was made, and the arterialized medullary vein draining the AVF was found to be blue and without arterial sound by microdoppler examination. The draining vein that entered the intrathecal space near the dural penetration of the posterior nerve root was coagulated and divided. Postoperative course: the SDAVF disappeared on postoperative spinal angiography. The patient made a complete recovery.
[Discussion and conclusion] The anatomical complexity of the pelotons based on the histological findings may explain the difficulty in achieving adequate embolization of the fistula in some cases and the tendency of the SDAVF to recur after endovascular treatment. The extradural removal of arterial microvascular"pelotons”resulted in shrinkage of the arterialized medullary vein in this case.
Free Papers
A Study of Anatomical Positions of a Cervical Vertebral Body and its Posterior Arch
Satoshi NORI, et al.
We have taken account of the vertical level of the upper edge of one posterior arch as compared to that of the upper margin of its vertebral body when selecting the intervertebral spaces to decompress for selective cervical laminoplasty.
The purpose of this study is to verify that there is regularity in the relation of anatomical position between a cervical vertebral body and its posterior arch.
The study consists of 30 patients with cervical spondylotic myelopathy(CSM) and 27 patients with whiplash injury(N). We measured the vertical distance between the upper margin of a vertebral body and that of its posterior arch in lateral cervical Xrays.
We divided each distance value by the height of each vertebral body, and defined it as % lamina height. We calculated each % lamina height from C3 to C7 in each patient, and analyzed the data statistically.
In both groups, as the vertebral level goes up, % lamina height becomes greater, and the posterior arch takes a lower position than the vertebral body. Posterior arches take a higher position than vertebral bodies in the aged patients of group N.
There is a regular relation between the vertical level of a vertebral body and that of its posterior arch.
Cervical Radiculopathy Associated with Drop Finger
Toshiki KURODA, et al.
Seven patients with cervical radiculopathy showing"drop finger”are reported."Drop finger”means inability of full extension of fingers at MP joints in wrist extended position. The C8 nerve root was disturbed in six patients, and the C7 nerve root in one. All patients suffered pain around the scapula at the beginning of symptoms. The spurling test was positive in all patients. Patients with a C8 nerve root lesion presented significant weakness of the intrinsic muscles of the hand. Six patients were treated with microsurgical posterior foraminotomy and herniotomy, and one was treated conservatively. Four cases suffered from disc hernia, and the other 2 from foraminal stenosis due to spondylosis. Six patients with cervical radiculopathy accompanied by drop finger showed numbness in the ulnar side of the hand and weakness of the intrinsic muscle. Therefore it is important in the differential diagnosis to distinguish cubital tunnel syndrome from posterior interosseous nerve palsy.
Pain around the scapula as an initial symptom and a positive Spurling test were also important clinical findings in the differential diagnosis of peripheral nerve disturbance.
A Novel C1-2 Instrumentation Method by Combination of C1 Lateral Mass Screw and C2 Laminar Hook Claw Fixation
Takanori NIIMURA, et al.
Purposes: A High riding vertebral artery(VA) often interferes with C1-2 transarticular or C2 pedicle screwing. We introduce a novel C1-2 fixation method using a C1 lateral mass screw and C2 hook claw.
Materials & Methods: A 67-year-old female patient with rheumatoid arthritis had atlanto-axial subluxation. She complained of tingling in both upper extremities and discomfort in the chest in the flexion position. Because the symptoms had gradually aggravated in spite of conservative treatment, posterior fusion surgery was indicated. On 3D-CT angiography images, a high riding VA was detected on the left side. The narrowest portion of the left C2 pedicle was measured to be 2.1 mm on the axial plane. During surgery, bilateral C1 lateral mass screwing and C2 pedicle screwing on the right side were performed. On the left C2 lamina, one bone hook claw was made using an off-set laminar hook(Oasys). Connection between the C1 lateral mass
screw and the claw was done, applying reduction force, without any difficulties.
Results: Her symptoms disappeared immediately after the surgery. The post-operative course has been uneventful. Until now, 4 months after surgery, there has been no instrumentation failure.
Conclusion: C1-2 fixation by a combination of C1 lateral mass screw and hook claw on the C2 lamina is feasible. This technique is highly recommended for C1-2 lesion associated with high riding VA.
Occipito-Cervical Fusion Using a Hook and Rod System with C3 Pedicular Hook
Takao MOTOSUNEYA, et al.
We performed occipito-cervical fusion using a hook and rod system for 10 patients with unstable lesions at the craniocervical junction such as rheumatoid spine and os odointoideum. The compact Cotorel-Dubouseset(CCD) cervical system was adopted. The claw mechanism was applied bilaterally between the hook of the C2 lamina and the hook of the C3 inferior articular process, and the two rods were connected with the occiput using screws. There were no complications during surgery. Solid bony fusion was confirmed in all cases and no cases became worse. The average duration of surgery was 195 minutes, and the average volume of blood loss was 320 ml. In conclusion, occipito-cervical fusion using a hook and rod system is easy and safe. Especially, the claw mechanism between the hook of the C2 lamina and the hook of the C3 inferior articular process offers secure fixation and is a useful procedure.
Foramen Magnum Decompression Using a Boat Shaped Sheet of Expanded Polytetrafluoroethylene(ePTFE)
Satoru SHIMIZU, et al.
In foramen magnum decompression for Chiari malformation, application of sutures between expanded polytetrafluoroethylene(ePTFE) dural substitutes and the dura mater is often frustrating because of the difficulty in holding the graft in a deep and narrow field. To resolve this problem, we have developed a boat-shaped graft made from a triangulate ePTFE sheet by pinching each angle with a suture. Production of standing edges of the sheet facilitates holding flaps for secure suturing, more rapid than with the conventional approach using a flat sheet.
Spinal Shortening Using Ultra-High Molecular Weight Polyethylene Cable and Rectangle Rod
Masahiko MIYATA, et al.
Posterior spinal shortening is one of the surgical methods to treat pseudoarthrosis of osteoporotic vertebral fractures. We report 2 cases of spinal shortening using ultra-high molecular weight polyethylene cable(UHMWPEC) and rectangle a rod followed up for more than 1 year.
Posterior spinal shortening using a rod and wire has been reported before. One of its advantages is that when late shortening or another vertebral collapse occur, there are fewer troubles than in the pedicle screw system such as pull-out, cutthrough or migration of screws. We used UHMWPEC instead of wire combined with a rectangle rod to treat pseudoarthrosis of osteoporotic vertebral fractures. The advantages of UHMWPEC compared with wire are;(1) safer and easier to pass under the lamina,(2) less damaging to neural tissues on postoperative breakage,(3) superior strength to hold the lamina because of its wider contact area,(4) easier evaluation of surrounding tissues on CT and MRI.
Spinal shortening using UHMWPEC and a rectangle rod was a good method to treat pseudoarthrosis of osteoporotic vertebral fractures.
Clinical Results of Surgical Treatment for OPLL of Thoracic Spine
Shigeyuki KITANAKA, et al.
The purpose of this study is to investigate the clinical results of surgical treatment for ossification of the posterior longitudinal ligament(OPLL) in the kyphotic part of the thoracic spine. Three operative procedures were performed for 9 cases with OPLL of the upper and middle thoracic spine. Posterior decompression with fusion was indicated for 4 cases, anterior decompression via posterior approach for 3, and posterior decompression for 2. Preoperative walking ability, clinical results, and radiological findings were evaluated for each surgical method. Radiological findings were evaluated by type of ossification lesion, ossification-kyphosis angle of decompression area and change of kyphosis angle. Postoperative progress of kyphosis was associated with poor neurological recovery. Clinical results were good for cases with little change in the kyphosis angle after operation. We thought that a dynamic factor played a part in the clinical results, because the posterior decompression with fusion group obtained good recovery, and that posterior decompression with fusion was a useful operation even for severe anterior compression of the spinal cord.
Operative Techniques of Micro DREZ-otomy(Sindou)for Neuropathic
Hiroshi TAKAHASHI, et al.
［Introduction］Pain mediating fine sensory fibers gather at the lateral side of the dorsal rootlets near the DREZ region and enter the posterior horn. On the other hand, thick sensory fibers run on the medial side of the posterior rootlets and enter the posterior funiculus. Thus, a lesion at the lateral side of the posterior rootlets and DREZ area results in anesthesia in the corresponding dermatomes, while the other sensations mediated by thick fibers are preserved. The first operation of this idea was performed in a patient with Pancoast syndrome by Sindou in 1972; after that, the indications for this operative method widened to include neuropathic pain, such as intractable pain caused by root avulsions. There are mainly two operative methods. Sindou opened the spinal cord under microscopic view and coagulated the DREZ region with a bipolar coagulator, while Nashold made DREZ lesions by a radiofrequency method, inserting a fine electrode into the DREZ region. We will report our experience of Sindou's method, mainly for cases with root avulsions.
［Operative Methods］First, we perform hemilaminectomy and open the dura mater longitudinally. Then we introduce a microscope, incise the arachnoid membrane, and inspect the area of root avulsion. The DREZ region in the area of root avulsion appears a little bit dented and yields easily to pressure by the fine tip of the aspirator. The identified DREZ region is opened and coagulated with a fine bipolar coagulator from the caudal to the rostral segment. Insufficient coagulation may result in recurrence of the intractable pain. While coagulating, we must pay attention to the fact that there are the posterior funiculus at the medial side and the pyramidal tract at the lateral side of the lesion. After enough coagulation is done, the spinal cord is closed by fine stitches in the pia mater.
［Discussion］With the techniques of Micro DREZ-otomy(Sindou), we can control the intractable deafferented pain in many cases of root avulsion. At this time, according to our clinical experience, we should sufficiently coagulate the DREZ-region for good results, while preserving the posterior funiculus on the medial side and the pyramidal tract on the lateral side of the lesion.