Surgical Technique for Spine and Spinal Nerves
Vol.8 No.1(2006)

Main Theme 1: Recovery Shot to Overcome the Difficult Surgical Conditions
G-Rod SSI for Multiple Metastatic Spinal Tumors
Hiroshi TAKEI, et al.
Three cases of multiple metastatic spinal tumors surgically treated with G-rod SSI are reported.
[Case 1] A 67-year-old man with multiple metastatic prostate cancer in the thoracic and lumbar spine with destruction of the vertebral body at T7 and 11. [Case 2] A 55-year-old man with multiple metastatic liposarcoma in the thoraco-lumbar spine with canal stenosis from T3 to T5, T8 to T10, and L1 to L2 due to the metastases. [Case 3] A 53-year-old woman with sataged metastases of hemangiopericytoma at T2, L5, and C5. Preoperative paresis and deterioration of ADL improved immediately fter each surgery in all cases.
As a strategy for the multiple metastatic spinal tumors, surgery has not always been considered because of limited prognosis. Extended instrumentation necessary for long fusion has also been thought to result in lower cost performance. However, recovery of QOL by relief of pain and paresis immediately after the surgery may motivate the patients and their family. Decompression and fusion with G-rod SSI, which costs less and gives sufficient rigidity, may be one of the treatment ptions for multiple metastatic spinal tumors.
A Less Invasive Posterior Decompression Technique for Revision Surgery of Lumbar Spinal Canal Stenosis
Naoki OKUBO, et al.
In posterior decompression for revision surgery of lumbar spinal canal stenosis(LSCS), an extended approach tends to be required for sufficient decompression, which causes additional invasion of the paraspinal muscles, ligaments, and facet joints. We developed a less invasive posterior revision surgery for LSCS, applying our minimally invasive surgery method.
The surgery was performed using a surgical microscope. Via midline approach, the edge of the remaining lamina was exposed with minimal damage to posterior elements. Tilting the surgical microscope appropriately, the lamina and medial rim of the facet joint were drilled with a 2-mm diamond burr until the shoulder of the nerve root was decompressed. After removing the osteophyte, the remaining ligamentum flavum and the extra-dural scar, the decompressed nerve root and pulsation of the dural sac were observed.
The subjects were two patients with LSCS which developed after previous posterior lumbar surgery. In both cases, clinical symptoms were improved in the short term after surgery, and postoperative CT revealed that the decompression was successful with the facet joints preserved.
Using this technique, we could easily approach the extra-dural space with less invasive exposure of posterior elements, and could decompress both dural sac and nerve roots sufficiently with a small amount of bone resection. This revision technique may be useful for cases which do not require spinal fusion.
Thoracoscopic Revision for CPC Anterior Protrusion after Vertebroplasty
Hiroaki OMATA, et al.
We report a case of thoracoscopic revision for anterior protrusion after vertebroplasty. A 77-years-old female had　fallen down twice before and had presented with severe back pain for many years without any neurological deficit. Osteoporotic　vertebral fracture, pseudoarthrosis and segmental kyphosis were found at T11, T12 and L1 levels. MRI revealed a　necrotic area in T12. Vacuum cleft was identified on CT images. Percutaneus transpedicular vertebroplasty was performed in　August, 2001. Calcium phosphate cement(CPC) was injected into the T12 vertebra. After the operation, symptoms were　slightly improved, but 2 months later she presented with tardy paralysis. Vertebral collapse and local kyphosis had progressed　due to anterior protrusion of the CPC. The JOA score deteriorated to 7.5 points(11 full marks being normal). In January 2002,　thoracoscopic removal of anteriorly protruded CPC fragments, T12 corpectomy and anterior reconstruction with a titanium　mesh-cage were performed, after posterior short instrumentation as augmentation. After the operation, paralysis was reduced.　By follow-up 3 years later, she can ambulate outside with moderate back pain.
Our Methods to Avoid Postoperative Liquorrhea in Cases with Spinal Disorders
Isao KITAHARA, et al.
[Purpose] Postoperative liquorrhea is a troublesome complication, which sometimes causes meningitis and requires re-operation in spinal surgery. In order to avoid postoperative liquorrhea in spinal as well as brain surgery, we have adopted a special method to seal the dura mater using gelfoam and fibrin glue. We present briefly our experiences with this method.
[Materials and methods] Out of 98 spinal operations performed in the Department of Neurosurgery, Tokyo Metropolitan Neurological Hospital since 2004, 22 cases needed dural closure or dural sealing with our special methods. Of these, 2 cases had had dural lacerations during decompressive procedures for atlanto-axial anomaly, and another 20 cases had undergone intradural operations for spinal tumors or vascular disorders.
[Methods] At first, a conventional gelfoam of size 10x10x15 mm is longitudinally sliced into three pieces, each 3.3 mm in thickness. Each gelfoam piece is then soaked with fibrinogen solution. After the surface of the dura mater has become dry, and each of the gelfoam pieces have been adjusted to the form of the dural defective, they are placed on the defected or lacerated area of the dura mater. After that, we drip enough thrombin liquid to cover these areas. Over the thrombin liquid, we put a further gelfoam strip to make a closerb seal.
[Results] All the cases except one showed no signs of CSF leak on MRI images. A case with Chiari Malformation who underwent wide dural plasty for foramen magnum decompression had mild liquorrhea on MRI but he was treated once with a blood patch without any serious sequelae and his neurological status improved significantly.
[Conclusion] We conclude that this closure method of the dura mater is clinically effective and can reduce the probability of CSF leak and associated problems.
Lumbosacral Tuberculous Discitis Successfully Treated by Posterior Lumbar Interbody Fusion
-A Case Report-
Noriyuki BABA, et al.
We describe a case of lumbosacral tuberculosis associated with lumbar fistula, surgically treated by single stage curettage and interbody fusion via posterior approach.
Case report: A 28-year-old man came to our institution because of posterior lumbar abscess spontaneously draining with yellowish purulent discharge. Purified protein derivative test(Mantoux) was 40 mm in diameter at 48 hours(positive). There were no neurological findings. On X-rays, narrowing of L5/S1 disc space and destruction of inferior L5 and superior S1 body were noted. On T2-weighted MR images, high intensity areas were detected in the L5/S1 disc and in front of the L5 and S1 vertebrae. He was diagnosed as spinal tuberculosis. In spite of irrigation and chemotherapy(INH, RFP, SM, PZA) over two months, the purulent discharge did not decrease. Therefore surgical treatment was selected. Under general anesthesia, the posterior abscess was curetted. After bilateral total facetectomies, thorough curettage in the disc space and lower part of L5 body was done. Iliac bone was grafted by posterior lumbar interbody fusion(PLIF). He also underwent posterior instrumentation with intrasacral rod fixation technique. The post-surgical course was uneventful. Solid bone fusion was obtained 17 months after surgery.
Our Methods to Avoid Postoperative Liquorrhea in Cases with Spinal Disorders
Yoichi JIN, et al.
[Purpose] Postoperative liquorrhea is a troublesome complication, which sometimes causes meningitis and requires re-operation in spinal surgery. In order to avoid postoperative liquorrhea in spinal as well as brain surgery, we have adopted a special method to seal the dura mater using gelfoam and fibrin glue. We present briefly our experiences with this method.
[Materials and methods] Out of 98 spinal operations performed in the Department of Neurosurgery, Tokyo Metropolitan Neurological Hospital since 2004, 22 cases needed dural closure or dural sealing with our special methods. Of these, 2 cases had had dural lacerations during decompressive procedures for atlanto-axial anomaly, and another 20 cases had undergone intradural operations for spinal tumors or vascular disorders.
[Methods] At first, a conventional gelfoam of size 10x10x15 mm is longitudinally sliced into three pieces, each 3.3 mm in thickness. Each gelfoam piece is then soaked with fibrinogen solution. After the surface of the dura mater has become dry, and each of the gelfoam pieces have been adjusted to the form of the dural defective, they are placed on the defected or lacerated area of the dura mater. After that, we drip enough thrombin liquid to cover these areas. Over the thrombin liquid, we put a further gelfoam strip to make a closerb seal.
[Results] All the cases except one showed no signs of CSF leak on MRI images. A case with Chiari Malformation who underwent wide dural plasty for foramen magnum decompression had mild liquorrhea on MRI but he was treated once with a blood patch without any serious sequelae and his neurological status improved significantly.
[Conclusion] We conclude that this closure method of the dura mater is clinically effective and can reduce the probability of CSF leak and associated problems.
Main Theme 2: Safe Operative Techniques for Spinal Cord Lesions
Technical Points of Anterior Decompression Surgery via Posterior Approach for Thoracic Myelopathy
Shigeru HIRABAYASHI, et al.
The important technical points of anterior decompression surgery via posterior approach for thoracic myelopathy due to OPLL, intervertebral disc herniation, or burst fracture of the vertebral body, are as follows: Laminectomy is initially performed at the most affected level. In OPLL, the beak-shaped OPLL is thought to be pathognomonic and an indication for operation. To provide a wide visual field and working space for the decompression procedure in front of the dura mater, adequate resection of the posterior surface of the transverse process and total facetectomy are performed. With the nerve root lifted, an air drill can be inserted bilaterally into the spinal canal from both the cranial and caudal sides. In OPLL, the ossified lesion is enucleated and separated from the posterior surface of the vertebral body, and finally removed anteriorly with the dura mater. Violent separation of the OPLL from the dura mater must be avoided. Special attention must be paid during the separation procedure at both the cranial and caudal ends of OPLL. After confirmation of complete decompression, spinal fixation using a pedicle screw system is additionally performed.
A Less Invasive Posterior Decompression Technique for Revision Surgery of Lumbar Spinal Canal Stenosis
Atsushi HONDA, et al.
In posterior decompression for revision surgery of lumbar spinal canal stenosis(LSCS), an extended approach tends to be required for sufficient decompression, which causes additional invasion of the paraspinal muscles, ligaments, and facet joints. We developed a less invasive posterior revision surgery for LSCS, applying our minimally invasive surgery method.
The surgery was performed using a surgical microscope. Via midline approach, the edge of the remaining lamina was exposed with minimal damage to posterior elements. Tilting the surgical microscope appropriately, the lamina and medial rim of the facet joint were drilled with a 2-mm diamond burr until the shoulder of the nerve root was decompressed. After removing the osteophyte, the remaining ligamentum flavum and the extra-dural scar, the decompressed nerve root and pulsation of the dural sac were observed.
The subjects were two patients with LSCS which developed after previous posterior lumbar surgery. In both cases, clinical symptoms were improved in the short term after surgery, and postoperative CT revealed that the decompression was successful with the facet joints preserved.
Using this technique, we could easily approach the extra-dural space with less invasive exposure of posterior elements, and could decompress both dural sac and nerve roots sufficiently with a small amount of bone resection. This revision technique may be useful for cases which do not require spinal fusion
Surgical Treatment of Intramedullary Thoracic Cord Tumor
Minoru HOSHIMARU, et al.
(Object) The thoracic cord is considered to be vulnerable to injury. Indeed, the surgical outcome of intramedullary ependymoma is worse in the thoracic cord than in other regions, as we have previously reported. In this study, surgical outcomes of intramedullary thoracic cord tumors were studied to clarify how to resect these tumors safely.(Patients and Methods) During the period from 2000 to 2005, 12 patients with intramedullary thoracic cord tumor(8 females and 4 males, ranging from 19 to 66 years of age) were treated surgically. Our series included 4 ependymomas, 2 astrocytomas, 2 hemangioblastomas, 3 cavernomas, and 1 metastatic tumor.(Results) Two patients with astrocytoma underwent biopsy and 9 others underwent total resection of the tumor. Fine manipulation was required to resect the tumor. One patient with a cavernoma improved after surgery, probably because of decompression of the cord by evacuation of the hematoma. Two patients showed myelomalacia during surgery and neurological deterioration after surgery. Tumors were totally resected without significant sequela in 7 patients.(Discussion and Conclusion) A well-demarcated intramedullary thoracic cord tumor can be resected safely. However, a small number of intramedullary thoracic cord tumors are associated with myelomalacia and give poor surgical results.
Surgical Approach in Cases with Intramedullary Cord Tumors Located in the Lateral or Marginal Area of the Spinal Cord
Hiroshi TAKAHASHI, et al.
[Introduction] When an intramedullary cord tumor is located in the lateral marginal area, the midline approach is not always appropriate or convenient for tumor removal. We retrospectively analyzed the operative results of intramedullary cord tumors located in this areas.
[Materials and methods] We treated 10 cases with intramedullary tumors located in the lateral or marginal area of the cord. 4 had astrocytomas, 2 hemangioblastomas, 2 subpial neurinomas, one cavernoma and one ependymoma. We selected an approach through the dorsal root entry zone(DREZ approach) in 5cases, and besides, one case with gliosis underwent cord biopsy by DREZ approach. Posterior midline approach was performed in 2 cases and, for subpial tumors, we used an open cut method through the small appearance of the tumors on the cord surface. [Results] In all cases except the biopsy, total or extensive removal of the tumors was accomplished. In the cervical area, DREZ approach was first hampered by abundant dorsal rootlets; however, under microscopic view, the tumors were gradually exposed and finally removed. At the thoracic level, there was ample space between the dorsal rootlets to remove tumors uneventfully by this method. For two astrocytomas located unilaterally in the marginal area of the cord, we selected a posterior midline approach in one of these, the operation resulted in an incomplete Brown-Sequard syndrome. In cases treated by open cut method, sensory disturbance often appeared due to sectioning of dorsal rootlets and the DREZ area invaded by the tumors.
[Conclusion] We should tailor an appropriate approach to remove intramedullary cord tumors located in the lateral or marginal area of the cord
Occipitocervical Fusion in Patients with Rheumatoid Arthritis Using
Hook and Plate-Rod System(CCD-Cervical)
Koji SATO, et al.
We did spinal operations with Iso-C3D and navigation system. We reviewed tips of a device of use of these systems by each operation. An examination item is anesthesia at a special operation table, configuration in an operating room, disinfection drape, set of a reference, time to need for a cash register, being bombed dosage, utility of navigation. Configuration of an anesthesia apparatus, piping of an intubation tube in Jackson Spinal Table of a product made in OSI company, face protection apparatus were perioperative, and the meeting with anesthesiology crossed the establishment of the miller which watched a face divergently. We had to do 360 degrees drape to the patient we were perioperative, and to image CT. We made K-wire of 3 mm in epistatic spinous process in lumbar spine, and methods to be able to be accompanied were good. We contributed to orientation of field of operation as well as the correct establishment of implant as a merit of using navigation. Orientation in minimally invasive surgery in particular got possible to keep an invisible part under control in real time and was effective.
Fluorescent Chemonavigation Using 5-Aminolevulinic Acid in Surgery for Intramedullary Spinal Tumor
Satoru SHIMIZU, et al.
To achieve comprehensive intramedullary spinal tumor surgery, we have applied intraoperative fluorescent chemonavigation using 5-aminolevulinic acid(5-ALA), which has been established to facilitate the distinction of cerebral gliomas from non-tumor tissue. A 19-year-old male with an intramedullary spinal tumor at the C4/5 level was the subject. He underwent surgery following administration of 5-ALA orally. The tumor was exposed and showed reddish fluorescence on exposure to laser light having a peak wavelength of 405±1 nm. Analysis of the spectrum of fluorescence revealed two emission peaks at 635 and 704 nm, compatible with those of protoporphyrinIX, a metabolic product of 5-ALA accumulating specifically in tumor cells. Laser examination after removal of the main mass revealed a tiny area of tissue embedded in the anterior raphe, having the same emission peaks. This was interpreted as a residual fragment of the tumor and removed. Pathological diagnosis including the finally removed tissue was ependymoma. The present method may be applied to other intramedullary spinal tumors to identify residual tumors and improve the completeness of surgical removal.
Computer-Assisted Navigation for Microendoscopic Fenestration in Cases of Lumbar Canal Stenosis
Naoki NAKATANI, et al.
One of the largest drawbacks of endoscopic the surgery is surgeon's disorientation. In order to avoid this, we used a computer-assisted navigation system for conducting microendoscopic laminotomy(MEL) in patients with lumbar spinal canal stenosis. From November 2004 to April 2005, 42 patients underwent MEL using the navigation system. This system allowed the surgeon to navigate the high-speed drill safely during decompression of the nerve roots. Also, we were able to complete subsequent preparations for the navigation system within 10 minutes. However, errors between the views of the navigation system and those of the endoscope occurred in 4 cases, because the reference arrays were mistakenly disturbed and had moved. In MEL, one difficulty in using surface mapping is in the ability to register the lumbar spine because of the lack of a defined bony point. We therefore, registered the lumbar spine by correlating two fluoroscopic images during surgery with the virtual three-dimensional images reconstructed from preoperative computed axial tomography scans. The navigation system was found to be very useful for minimally invasive spinal endoscopic surgery. Future combination of the navigation system and microendoscopic surgery may confidently promise safe decompression for patients with lumbar spinal canal stenosis.
Main Theme 3: Minimally-Invasive Operative Techniques-Cervical Spine
4 Cases of Cervical Posterior Fusion Using C2 Pedicle Screws
Nobuyuki SHIMOKAWA, et al.
We report 4 cases of posterior fusion using a C2 pedicle screw, which enabled short fusion. Patients were three males and one female, between 48 and 78 years old. Occipito-axial fixation was performed for a Jefferson fracture and an atlanto-axial subluxation due to Rheumatoid Arthritis. Atlanto-axial fixation with C1 lateral mass screw and C2 pedicle screw was performed for two cases of C2 odontoid fracture. The authors have developed a new device to navigate the trajectory of screw insertion in the axial plane for posterior cervical fixation. The device is composed of two, stainless wires, long and short were welded together at an angle of 25 degrees at the top. The device was used by adjusting the long wire to a vertical line to the floor and the short wire for adjustment of axial direction of the screw. All C2 pedicle screws were inserted safely using the original device in addition to a fluoroscopic guide. Satisfactory fixation was obtained in these 4 cases.
Our technique of C2 pedicle screw insertion with the original device was useful for posterior fixation.
Our Minimally Invasive Cervical Expansive Open-Door Laminoplasty( K-Method) Using a Spinoplastic Hydroxyapatite Space(r K-Spacer)
Shun-ichi KIHARA, et al.
We developed a less invasive open door cervical laminoplasty(K-method), and more than 1000 patients have already been treated by this method.
In this report, we shall demonstrate some important points and principles of the K-method using computer graphics, and show the answers to the 5 major questions: "How to make a surgical position?” "Why you can operate with only a 3 cm skin incision?” "Is it the same thing that the skin incision is very small and the surgery is less invasive?” "What is the Posterior Cervical Triangle?”, and "Why is the alignment of the cervical spine improved after K-method surgery?” It is a technique which can be mastered with a certain training, and we think that it provides a direction in discussions of the usefulness of surgical techniques for degenerative cervical spine diseases.
Posterior Cervical Herniotomy Using METRx Micro Discectomy System for Cervical Disc Herniation
Takuya FUJITA, et al.
Purpose: We have been performing posterior cervical herniotomy using the METRx Micro Discectomy system in patients with cervical disc herniation presenting with radiculopathy. The aim of this study was to assess the short-term clinical results of this procedure.
Materials and methods: Five patients with cervical disc herniation leading to radiculopathy underwent this procedure since May 2005. The mean age was 53 years, with C5/6 level in one case and C6/7 in four. The average follow-up period was 7 months. Clinical results were evaluated by 1) Tanaka's score(points 0-20), 2) operative time, and estimated blood loss, and 3) wound pain at post-op. day 1 using VAS score(points 0-10).
Results: The herniated discs were successfully removed in all patients from the axillary portion of the cervical nerve root without any complications, with an 18 mm small incision. Their symptoms resolved immediately just after surgery. Pre- Tanaka's score averaged 10.0 points, whereas the post-op score averaged 17.8 points, the recovery rate being 76.7%. The average operative time was 110 minutes and blood loss was less than 30 ml in all cases. Interestingly, the average of VAS scores of wound pain just post-op. was only 1.3 points.
Discussion and Conclusion: Posterior cervical herniotomy using the METRx Micro Discectomy system for cervical disc herniation provided good results and low invasiveness, in addition to a safe technique for the spinal cord due to using microscope.
A New Technique for Posterior Decompression at the Axis in OPLL Patients
Hideo HOSOE, et al.
We report a new technique for decompression of C2 laminae in OPLL(ossification of longitudinal ligament) patients. We preserve the attachments of many important muscles to the C2 spinous processes and bilateral laminar bases. This procedure for decompression at C2 consists of three parts; firstly midline decomprewssion, secondly dome fenestration of C2 laminae bot cranially and caudally, and thirdly oblique decompression at the lateral sides by declining the operation table and microscope, resulting in removal of the inner layer of the C2 lamina. After decompression the split spinous process is reinforced by grafting bone from the posterior arch of C1. The wide C2 spinous process which is usually more than 10 mm in width can make this procedure possible.
Since September 2004, 9 patients with OPLL have undergone this procedure. As for average operation time and blood loss, this new procedure was almost the same as the T-saw laminoplasty previously performed. However, this procedure guarantees early mobilization due to stable lamina and preserved attachments of muscles.
It is less invasive and may be effective in preventing postoperative problems, such as persistent axial symptoms, decrease of ROM and malalignment.
Spinal Fusion Using a Spinous Process Plate(S-Plate)-Clinical Results and Mechanical StrengthYusuke
NAKAO, et al.
[Purpose] In our hospital, a spinous process plate(S-plate) has been used for in situ short fusion since 1994. The clinical results and mechanical strength were evaluated.
[Materials] 88 patients, mean age 49. One case involved the cervical spine and the other 87 cases the thoracic and lumbar spine. 50 cases were disc herniation; this was the most frequent cause. 60 cases were 1 level fusion, 27 were 2 levels, and the one cervical case was 4 levels. The follow-up period was from 3 months to 11 years. Clinical results were evaluated in 74 cases which could be followed up for more than one year. Mechanical tests using a S-plate were also performed.
[Result] The mean JOA score improved from 13 to 25. The recovery ratio was 75%. The mean bone fusion ratio was 98% in 1 level fusion, and 92% in 2 levels. In the one cervical 4 levels case, bone fusion was observed. In mechanical tests, the strength of the plate against coronal bending force corresponded to a 2.5 mm Twinflex rod, and the strength against sagittal bending force corresponded to a 6.4 mm pure titanium rod.
[Conclusion] The S-plate is easy to apply, less invasive, and appears useful for in situ short fusion
A Unilateral Spinous Process Split-off Approach Preserving Attached Back Muscles for Bilateral Decompression of Lumbar Spinal Canal Stenosis
Kenichi CHATANI, et al.
[Purpose] Bilateral decompression through a unilateral approach in lumbar spinal canal stenosis(LSCS) is useful. In the conventional operative approach, however, the ipsilateral back muscles attached to the spinous process are elevated off. We present a new approach technique for the preservation of the ipsilateral back muscles.
[Methods] The technique is the following. Midline splitting of the spinous process is done without invasion of the back muscles and unilateral cutting is done at the base of the process. The cut unilateral process, attached to the back muscles, is retracted laterally and bilateral decompression through the unilateral approach is performed. Finally, the cut half of the process is sutured to the residual half. We followed up 12 patients with LSCS for more than one year after the operation and evaluated the clinical outcomes.
[Results] The mean operation time was 118 minutes and the mean blood loss was 121 g per interlaminar level. The only complication was a small dural tear. All patients obtained complete relief of sciatica and intermittent claudication, and the mean improvement rate of JOA score was 68%.
[Conclusions] Bilateral decompression through our unilateral spinous process split-off approach for LSCS provided excellent clinical outcomes. We consider that our approach contributes toward the anatomical and functional reconstruction of the ipsilateral back muscles.
Microscopic Unilateral Decompression(MUD)of Dural Sac for Lumbar Spinal Canal Stenosis
-Comparison with Conventional Bilateral Decompression
Yoshihiro YABE, et al.
[Purpose] We thought that microscopic unilateral decompression(MUD) of the dural sac for lumbar spinal canal stenosis was less invasive than conventional bilateral decompression. We compared the clinical results and surgical invasion of MUD with bilateral decompression.
[Materials and Methods] 59 patients underwent by MUD from July 2003 to April 2005. The mean age was 69 years and the average follow-up period was 4.6 months. We compared 59 patients who were operated on by MUD with 23 who were operated　on by bilateral decompression for the same period. We evaluated clinical results(JOA score), operation time, blood loss, CPK 1 day after operation, postoeperative day of ambulation, duration of postoperative wound pain and hospitalization period.
[Results] Between the MUD and bilateral decompression groups, the average JOA score, the average operation time and CPK value showed no meaningful difference. Only the average blood loss was significantly less in MUD. On the other hand, the postoperative day of ambulation, the duration of postoperative sound pain and the hospitalization period were significantly shortened in MUD.
[Discussion] MUD was minimally invasive surgery and could achieve decompression without damaging the facet joints. It was safer for the dural sac and nerve roots through the use of a microscope. In addition, postoperative pain was decreased and it was possible to plan early standing and shortening of the hospitalization period
Lumbar Interbody Fusion Using X-Tube Retraction System
Keisuke NAKANO
40 patients with degenerative lumbar spinal disease were treated by lumbar interbody fusion using the X-tube Retraction System. Out of 40 patients, 28 had degenerative spondylolisthesis, 3 had isthmic spondylolisthesis, 3 had lumbar spinal canal stenosis and 6 had recurrent lumbar disc herniation. 15 patients were treated by PLIF with dual rods and 25 were treated by TLIF with a single rod.
Telamon interbody cages were used in 29 patients and Interfix cages were used in 12. Operation time and blood loss were estimated and D-dimer was measured before and after surgery. Results were compared between X-tube surgery and conventional open PLIF.
Operation time was shortest in X-TLIF and blood loss was also least in X-TLIF. Blood loss was the most in open PLIF and operation time was longest in X-PLIF. D-dimer measured at 72 hours after surgery was lower after X-tube surgery than after open PLIF. Dural tear was seen in 2 cases of X-PLIF and spacer displacement in one case of X-TLIF. There was no case of post-operative neurological worsening. Lumbar interbody fusion using an X-tube retractor was considered to be less invasive than conventional open PLIF.
Posterior Oblique Lumbar Arthrodesis for Spondylolisthesis Using X-Tube
Shoji YAGI, et al.
We introduce a new surgical procedure for spondylolisthesis using an X-Tube, and compare the outcome and surgical invasiveness of this procedure with the conventional open procedure.
After the retractor is inserted on the symptomatic side, laminectomy is performed through one portal to obtain decompression of the dura and bilateral nerve roots. An interbody fusion cage is inserted obliquely, and pedicle screws are placed ipsilaterally.
Fifteen patients underwent this procedure. Lesions included degenerative spondylolisthesis in 9 patients and isthmic spondylolisthesis in 6(Group 1). Twenty patients with degenerative spondylolisthesis were treated by conventional open PLIF or PLF using bilateral pedicle screws(Group 2).
In Group 1 and Group 2, the average surgical duration was 250 and 175 minutes, the average volume of blood loss 150 ml and 340 ml, and CRP values 7 days after surgery 0.9 and 2.1 respectively. These parameters showed significant differences.
This novel surgical procedure has many advantages, such as limited muscle-splitting dissection, preservation of contralateral structures, and a small skin incision which allows a less painful postoperative course and a shorter hospital stay. This procedure seems to be a useful and minimally invasive form of surgery for spondylolisthesis compared with the conventional open PLF and PLIF
New Microendoscopic Decompression Method via Midline Interlamina Approach for Lumbar Canal Stenosis
-Microendoscopic Muscle Preserving Interlaminar Decompression; ME-MILD
Kazuyoshi YANAGISAWA, et al.
We describe a new microendoscopic decompression method via interlamina approach on the midline for lumbar spinal canal stenosis, and reviewe the technique and the short-term results.
The subjects were 12 patients with lumbar spinal canal stenosis classified as cauda equina type or mixed type. The mean age was 69.0 years, and the mean postoperative follow-up period was 10.6 months. We investigated the operative time, amount of blood loss in surgery, and JOA scores before and after surgery. In addition, with CT images, we evaluated the shape of the facet joints. The average operative time was 113 minutes per level, and amount of blood loss was 60.2 per level. The
mean JOA score before surgery was 15.1 points, which improved to 26.7 points after surgery. Postsurgical CT showed that decompression of all facet joints was successful and without damage. Using our procedure, the decompression can be trumpetshaped, so that paraspinal muscles and facet joints can be sufficiently preserved and orientation is easy. Moreover, since no muscle tissue appears in the operative field, a good visual field is obtained. Detachment of the ligamentum flavum and dura mater is comparatively easy, and the procedure can be adapted in a case of central type canal stenosis.
Experience of Minimally Invasive Spine Surgery without Using Endoscopy for Lumbar Disc Herniation
-METRx Radiance Illumination System(in Comparison Love's Method)-
Yoshitaka ISHIZAKI, et al.
The authors report the usefulness of the METRx radiance illumination system in the treatment of lumbar disc herniation. The system enables minimally invasive surgery equivalent to the MED method by using a special light source instead of the endoscope, the MED retractor system, and the surgical procedures of Love's method.
The mean operation time required for the surgery using METRx radiance illumination system was 38±6(24－51) minutes, about 10 minutes longer when compared with 29±5(15－48) minutes for Love's method. The time required to set the retractor for the procedures made the difference in the total operation time. There was no significant difference in time the required for the procedures after placing the retractor.
The advantages of the METRx radiance illumination system method, when compared with MED method, were that there was no learning curve because an endoscope was not used, and the system could be introduced at a relatively lower cost because the same surgical instruments as in Love's method could be used.
Also it is not difficult for the surgeons to shift from the METRx radiance illumination system method to the MED method, and the system is useful in shortening the operation time of the MED method
Muscle-Preserving Interlaminar Decompression(MILD)
-A New Minimally Invasive Procedure for Lumbar Spinal Canal Stenosis
Yoichiro HATTA, et al.
Purpose: The aim of this study was to describe our new minimally invasive procedure and its preliminary results.
Materials & Methods: The initial 27 consecutive patients with LSCS were included in this study. A total of 61 levels were decompressed. There were 14 women and 13 men, and the mean patient age was 70.4 years.
Surgical Procedure: The supraspinous ligament was incised longitudinally and the spinous processes were exposed with an operative microscope. The caudal portion of the superior spinous process and cephalad portion of the inferior spinous process were drilled and the interspinous ligament was divided in the midline to extend the operation field. The lamina was drilled with a 2-mm diamond burr along the cranial and caudal edges of the lamina toward the lateral recess, without exposing the outer layer of the lamina. After en bloc resection of the ligamentum flavum, the decompressed nerve roots were observed.
Results: The mean operation time was 102 minutes per level, and mean estimated blood loss 34 g per level. The mean recovery rate with JOA score was 58.3%.
Conclusion: The advantages of MILD included bilateral symmetric surgical exposure, less invasion of the paravertebral muscles, and preservation of the facet joints and spinous processes as lever arms.
Free Papers
Sacral Perineural Cyst in Two Operative Cases
Eiichiro HONDA, et al.
Perineural cyst has been termed Tarlov cyst, and is defined as a collection of fluid between the endoneurium and perineurium. Most perineural cysts are located in the sacrum(S2, 3) and cause no symtoms. Rare cases to grow to a big size and cause local and radicular pain, intermittent buttock pain, and bladder dysfunction. So far there has been no consensus on surgical intervention. We now present two cases of perineural cyst at the level S2/3 who underwent operative treatment(ages: 34 and 43 years). Common symptoms of both cases were buttock pain after long standing or sitting, and instability on feet for a couple of years. The operative method was according to Casper's report. After sacral unroofing and exposure of the cyst, puncture of the cyst with complete aspiration of the fluid was performed. The cyst was partially excised and closure by dural plasty or plication of cyst wall was carried out, and the site was covered with finrin glue. The excised cyst wall included nerve tissue in one case. However, each outcomes were good.
Conclusion: Many operative methods for the sacral perineural cysts have been reported. Fibrin infusion into the cyst under CT guide and placement of shunt tube was previously performed for protection of the obstracted valve mechanism, but this method invited the complication of aseptic meningitis and granulation mass. The surgical method advocated by Casper and Mummaneni is to collapse the cyst, perform imbrication or plication of the cyst wall and pack the dead space with fat and fibrin glue, which protect the obstructed valve, although there is no obvious evidence for this. Their method resulted in long-term relief of the symptoms. Although nerve tissue was included in the excised cyst wall, no symptoms occurred. For this reason, we believe that nerves adhering to the inner cyst wall may be degenerate and non-functioned.
Surgical Short Term Results of Lateral Fenestration for Lumbar Foraminal Stenosis
Masana YONEDA, et al.
[Purpose] We treated 6 patients with L5 radiculopathy due to foraminal stenosis. In this study, we report the short-term surgical outcome and our evaluation of lateral fenestration without instrumentation.
[Materials & Methods] 6 patients(42-61 years old: average 52.7) who underwent lateral fenestration of L5 root were investigated. 2 cases of re-operation were included. Decompression surgery was performed by partial resection of the superior articular process of S1 via posterior approach in all cases. Posterolateral fusion with harvested iliac bone graft was added only for re-operation cases. We evaluated the clinical results by the JOA score and the improvement rate.
[Results] All cases have improved clinically; pre-operative JOA scores 11.8±4.3 points have changed to 23.8±2.1 points(average improvement rate: 69.4±15.2%) after operation.
[Discussion] According to some past reports, instrumentation should be performed together with this operation. However, we could prove that the post-operative improvement rate was high and there was no appearance of new lumbago without
instrumentation.
[Conclusion] In foraminal stenosis, the short-term clinical results of decompression surgery by partial resection of the superior articular process without instrumentation were evaluated as successful.
Microendoscopic Discectomy for Lumbar Disc Herniation
-Early Clinical Results in 30 Consecutive Cases
Kimiaki SATO, et al.
[Purpose] To assess the early clinical results after microendoscopic discectomy(MED) for lumbar disc herniation.
[Material and Methods] Between November 2002 and April 2005, thirty consecutive patients with single-level unilateral lumbar disc herniation at L4/5 or L5/S1 were each treated using MED. These 30 patients included 19 males and 11 females, with a mean age of 34.8 years. The patients were classified in three groups chronologically; the earliest 10 patients(Group I ), the next 10(Group II ) and the most recent 10(Group III ). The clinical results in these 3 groups were compared on the bases of operative duration, blood loss, total dosage of analgesics administered, period to initial walking, and patient-based outcome using VAS and RDQ.
[Results] There was no significant difference between the three groups in blood loss, total dosage of analgesics administered, period until walking, or patient-based outcome. However, there was a difference in the operative duration which was significantly shorter in Group II and in Group III compared with Group I .
[Discussion and Conclusion] MED for lumbar disc herniation could achieve good early clinical results; however, there appeared to be an initial learning curve in the use of this procedure.
Foraminal and Extraforaminal Lumbar Fenestration with Microscope and Tubular Retractor System
Sho DOZONO, et al.
Microscopic lumbar fenestration using a tubular retractor was performed on eight patients who had foraminal or extraforaminal lumbar radiculopathy. The advantages and problems of this procedure were evaluated.
Subjects were three men and five women with an average age of 68 years. The decompression level was L3/4 in one case< and L5/S1 in three cases. There were five cases of lumbar spondylosis, two of degenerative scoliosis, and one of lumbar disc hernia.
A paramedian skin incision of about 2 cm was made and the paravertebral muscle was dilated, identifying the lumbar level with fluoroscopy. Then a tubular retractor was inserted. The muscle was retracted to expose the inferior border of the pedicle, pars interarticularis, and superior margin of the facet.
Leg pain was relieved in all the patients, and there were no complications.
It is difficult, especially at the L5/S1 level, to retract the paravertebral muscle and expose the extraforaminal compartment using a paramedian approach. However, in comparison with a double-bladed retractor, a tubular retractor makes it easier to expose the far-lateral space when using this approach.
Pseudocystic Degeneration of the Lumbar Ligamentum Flavum
Yuichiro NISHIJIMA
We treated 16 patients with pseudocysytic degeneration of the lumbar ligamentum flavum.
Unilateral radiculopathy and remission and regression of symptoms were clinical features of this diseasese.
Mild instability was identified in the lateral x-p film. Repetitive microtrauma from the mild spinal instability may be one of the pathological mechanisms of pseudocystic degeneration.
Hypertrophied ligamentum flavum was shown in MRI studies. In T2 weighted axial image, a double high intensity area was identified; one part was for the pseudocyst, the other for the dural tube.
Total resection of the ligamentum flavum was indicated to obtain satisfactory clinical results after operative treatment.
Short-Term Outcome of Open-Door Laminoplasty with Kihara's Spinoplastic Hydroxyapatite Spacer
Keishi TSUNODA, et al.
[Purpose] Open-door laminoplasty with Kihara's spinoplastic hydroxyapatite spacer is a minimally invasive method with good clinical outcome. The purpose of this study is to investigate the single institution short-term outcome of open-door laminoplasty with Kihara's spinoplastic hydroxyapatite spacer, performed by the author.
[Materials and Methods] Between February 2004 and February 2005, 34 patients underwent open-door laminoplasty with Kihara's spinoplastic hydroxyapatite spacer. They consisted of 25 males and 9 females. Their ages ranged from 33 to 79(average 59.3) years. Operative time, blood loss, clinical outcome and complications were investigated.
[Results] Mean operation time was 211 minutes(range, 128－333). Mean blood loss was 141 ml　(range, 30－390). Mean preoperative JOA score was 10.3 points(range, 1.5－16.5), mean postoperative JOA score was 14.9 points(range, 8.5－17), and mean improvement rate was 73.9%. To compare the first series with the second, mean operation times were 243 and 180 minutes, mean blood loss 159 and 123 ml, mean preoperative JOA score 9.4 and 11.1 points, mean post operative JOA score 14.6 and 15.1 points, and mean improvement rate 73.8 and 74.0% respectively. There was no C5 palsy or deterioration of alignment of the cervical spine. One case underwent C3 laminectomy because of C3 hinge fracture.
[Discussion and Conclusion] Kihara's approach is a very useful procedure. Understanding the technique and gaining experience by performing many cases is the key to good results
Atlanto-Axial Fixation Using Lateral Mass Screw of the Atlas
Jun MIZUTANI, et al.
We report five cases treated by atlanto-axial fixation using a lateral mass screw of the atlas. All patients suffered from reducible rheumatoid atlanto-axial subluxation. They were one man and four women. Ages at surgery ranged from 49 to 76 years. Preoperative Ranawat neurological deficit score and pain grade were as follows: Four patients were Ranawat neurological deficit class I and one was IIIB. Four patients were pain grade 1 and the remaining one was pain grade 2. Lateral mass screws of the atlas were inserted via the posterior arch as reported by Tan et al. All lateral mass screws of the atlas were successfully placed. Although follow-up was short, no correction loss was seen.
Trans-articular screw fixation is biomechanically stronger but there is a potential risk of violation of the vertebral artery if this is aberrant. Atlanto-axial fixation using the lateral mass of the atlas and a pedicle screw of the axis is an alternative surgical procedure in such a situation
How Do You Operate on Extramedullary Spinocranial Tumor?
-Operative Prognosis of Spinal Meningioma and Nerve Sheath Tumor-
Naoki ASAMI
Purpose: The purpose of this paper is to describe the correct insertion of the AMSLU®cervical interbody fusion cage Materials & Methods: The subjects were 24 patients(16male,8female) who underwent anterior cervical fusion with AMSLU®(Eurosurgical, TOKIBO) interbody fusion cages from April 2004 to May 2005(one level: 20, two levels: 4, ages from 42 to 82). All cases were diagnosed as cervical spondylosis(myelopathy 17, radiculopathy 7) and operated from the right side under the microscope and image intensifier.
Results: Sinking of cage was found in all cases immediately after surgery without symptoms, and all patients were discharged in good condition. Every case showed osteosynthesis in computed tomography until one month postoperatively, and anterior bridge formation over several months.
Discussion and Conclusion: Many kinds of cervical interbody fusion cages are available in Japan, and this AMSLUcage has a unique form and the posterior side is opened. The author underlays the intersurface with an absorbable hemostat like Sergicel®(J & J) which can prevent backout of contents. An Interbody threaded cervical cage like AMSLU®is a very useful and standard surgical procedure because patients can walk and move immediate by after surgery without a cast.
Spinal Osteotomy for Kyphotic Deformity Associated with Walking Difficulty after Combined Surgery of Harrington Rod Instrumentation and Dwyer Cable Procedure for Idiopathic Scoliosis with Double Curve
-A Case Report-
Koki ANABUKI, et al.
We report a patient with kyphotic deformity associated with walking difficulty after combined surgery of Harrington rod instrumentation and Dwyer cable procedure for idiopathic scoliosis with double curve who was successfully treated by combined surgery of posterior closing osteotomy and anterior support surgery at one stage. Flat back syndrome is well known after posterior scoliosis correction surgery. Difficulty in walking could occur in extreme lumbar kyphotic deformity. Correction of kyphotic deformity in the posterior fused spine could be achieved by single posterior osteotomy without neurological complication. Kyphosis, however, due to surgically fused anterior and posterior spine needs combined anterior and posterior surgery. To avoid neurological complication wide exposure of the dural tube in posterior osteotomy was mandatory. Frequent positioning change during surgery was a problem at one stage combined surgery. We used one positioning change by prone positioning followed by lateral recumbent positioning. Hook system of osteoporotic bone mass is very useful for spinal fixation when pedicles are not well visualized by fluoroscopy. We recommend correction should be done at the center of the lumbar spine to obtain more than 25 degrees of lumbar lordosis
Posterior Interbody Arthrodesis with a Fibular Strut Graft for High-Grade Isthmic Spondylolisthesis in Adolescent
Masato OTA, et al.
The purpose of this study is to introduce the technique of posterior interbody arthrodesis with a fibular strut graft and discuss the results. The patient was a 15-year-old girl who complained of low back pain. Roentgenograms showed a Meyerding grade III L5/S spondylolisthesis(%slip=51%, slip angle=25 degrees). The operation was performed by posterior approach and no attempt was made to reduce the slip. After laminectomy of the proximal sacrum, a guide pin was inserted through the S1 vertebra into the antero-superior corner of the L5 vertebra. With the use of a cannulated reamer a tunnel was created, then harvested fibular strut grafts were inserted into the tunnel bilaterally. Roentgenograms and 3DCT demonstrated osseous fusion 20 months after surgery. JOA score improved from 17 to 29(full mark) points. In this technique, the dowel fibula provides structural support across the severely slipped level as well as a bone source to allow arthrodesis, so that it enables the patient to recover earlier and to obtain an excellent fusion. This surgery has been safely performed without neurological complications or discomfort at the fibular donor site. We conclude that it is an effective method for high-grade spondylolisthesis in adolescents.
Intraoperative Radiotherapy for Recurrence of Spinal Metastasis Previously Treated by External Radiotherapy
Taiji KONDO, et al.
The combination of conventional posterior surgery with intraoperative radiotherapy(IORT) was applied to manage recurrent spinal metastasis previously treated by external radiotherapy(ERT). The subjects were 66 patients(76 procedures). Eight patients and one patient received a second and third round of IORT respectively, for a further local recurrence of spinal metastasis after ERT. Out of 59 cases with motor weakness, 36(61%) attained at least one level of improvement according to Frankel's classification. Out of 50 patients, in whom more than 6 months follow-up observation was performed, nine(18%) developed re-recurrence The primary cancer sites of re-recurrence cases were radioresistive tumors such as renal cell cancer and thyroid cancer. ERT cannot be re-applied to recurrent spinal metastasis previously treated with a maximum dose of ERT, because of the high risk of radiation myelopathy and skin disorders. The result of conventional surgery may be unsatisfactory, since postoperative ERT cannot be performed. IORT can be applied to such a lesion, because the spinal cord is shielded and the skin is not irradiated in the procedure. The result of IORT for recurrent spinal metastasis previously treated by ERT is promising for local control and improvement of neurological manifestations.