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Norio Kawahara

Publications and source records attributed to Norio Kawahara.

At least 19 recordsLinked to original sources
PubMed2006

How many ligations of bilateral segmental arteries cause ischemic spinal cord dysfunction? An experimental study using a dog model.

STUDY DESIGN: Segmental arteries were interrupted bilaterally for up to 7 levels to study the effects on spinal cord blood flow and neurologic function in dogs. OBJECTIVE: To examine how many ligations of bilateral segmental arteries cause ischemic spinal cord dysfunction. SUMMARY OF BACKGROUND DATA: Interruption of bilateral segmental arteries for up to 3 levels has been reported not to damage spinal cord function. However, to our knowledge, the effects of ligating more than 3 levels have not yet been clearly determined. METHODS: There were 15 dogs divided into 5 groups: sham group, no ligation; group 1, ligation of bilateral segmental arteries at 3 levels (T11-T13); group 2, at 4 levels (T10-T13); group 3, at 5 levels (T10-L1); and group 4, at 7 levels (T9-L2). Spinal cord blood flow at T12 measured by laser Doppler flowmetry, and spinal cord-evoked and motor-evoked potentials were measured simultaneously until 10 hours after ligation. Neurologic function was assessed using a modified Tarlov grading system 1 week after operation in 20 other dogs divided into 4 groups (1, 2, 3, and 4). RESULTS: Spinal cord blood flow was 99.3%, 80.7%, 71.5%, 44.3%, and 25.0% in the sham group, and groups 1, 2, 3, and 4, respectively, 10 hours after ligation. Abnormal spinal cord-evoked potentials were observed in 2 of 3 dogs in group 3 and all 3 in group 4. Abnormal motor-evoked potentials were observed in 1 of 3 dogs in group 3 and all 3 in group 4. Postoperative neurologic evaluation identified all 5 dogs in groups 1 and 2, respectively, and 3 in group 3 as having grade 5. There were 2 dogs in group 3 and 3 in group 4 that had grade 4, and 2 in group 4 had grade 3. CONCLUSION: Interruption of bilateral segmental arteries at > or =5 consecutive levels risks producing a spinal cord ischemia capable of injuring the spinal cord.

Animals↗
PubMed2006

Complete segmental resection of the spine, including the spinal cord, for telangiectatic osteosarcoma: a report of 2 cases.

STUDY DESIGN: Two case reports of telangiectatic osteosarcoma treated with complete segmental resection of the spine, including the spinal cord. OBJECTIVES: To report the en bloc tumor excision, including the spinal cord, for telangiectatic osteosarcoma, and discuss the indication of cord transection and influence after cutting the spinal cord. SUMMARY OF BACKGROUND DATA: To our knowledge, there are no previous reports describing telangiectatic osteosarcoma of the spine and the subsequent en bloc excision of the spine, including the spinal cord. METHODS: The clinical and radiographic presentations of 2 cases with telangiectatic osteosarcoma are presented. Because these 2 cases already had complete paralysis for at least 1 month, it was suspected that there was no possibility of recovering spinal cord function. Complete segmental spinal resection (total en bloc spondylectomy) was performed. At that level, the spinal cord was also cut and resected. RESULTS: En bloc excision of the tumor with a wide margin was achieved in both cases. In the resected specimen, the nerve cells in the spinal cord had lapsed into degenerative necrosis. The pathologic findings showed that there was no hope for recovery of spinal cord function. CONCLUSION: En bloc spinal resection, including the spinal cord, is an operation allowed when there is no hope for recovery of spinal cord function. This surgery should be accepted as an option in spine tumor surgeries.

Adult↗
PubMed2006

Serum interleukin-6 response after spinal surgery: estimation of surgical magnitude.

BACKGROUND: Serum interleukin-6 (IL-6) has been used for quantitative estimation of the surgical magnitude of major cardiac and thoracoabdominal surgery, but there have been few studies assessing IL-6 as a marker of surgical magnitude of spinal surgery. METHODS: We investigated the changes in IL-6 response in comparison to other parameters of surgical magnitude and spinal surgery procedures. The study included 40 patients electively undergoing spinal surgery. The patients were divided into four groups: lumbar laminectomy with posterolateral fusion (PLF), lumbar laminotomy, lumbar open discectomy, and cervical laminoplasty. Serum IL-6, C-reactive protein (CRP), creatine kinase (CK), and the white blood cell (WBC) count were determined in venous blood before surgery, at the end of surgery, and 6 h and the first, third, and seventh days after surgery. RESULTS: Serum IL-6 peaked on the first day and returned to a normal value by the seventh day. The peak IL-6 concentrations on the first day after surgery significantly correlated with CRP, CK, duration of surgery, and estimated blood loss. Regarding lumbar surgeries, the peak IL-6 for laminectomy/PLF was significantly higher than that for laminotomy/open discectomy or for cervical laminoplasty. CONCLUSIONS: Serum IL-6 on the first day varied depending on the surgical procedure used. Therefore, it might be a quantitative marker of surgical magnitude following spinal surgery.

Adult↗
PubMed2006

[Surgical treatment for metastatic bone tumor].

Conventionally, palliative surgery has been commonly performed as pain management for bone metastasis which is regarded as terminal. Recently, medical treatment in this area has made great advances and so life expectancy of patients with cancer has been prolonged. The objective of surgical treatments is to maintain activities of daily living. Radical resection and reconstruction are used for the patients with long life expectancy, though palliative surgery is for the patients with short life expectancy.

Activities of Daily Living↗
PubMed2006

[Effects of bisphosphonate for quality and strength of bone].

Bisphosphonate prevents the fracture by controlling the function of osteoclasts and inhibiting bone absorption powerfully for osteoporosis. It is shown clinically that both alendronate and risedronate reduce postmenopausal osteoporosis patient's vertebral and nonvertebral fractures. Recently it became clear that bisphosphonate not only reduces bone absorption, but also improves bone quality such as bone microarchitecture and material properties. Furthermore, we showed using finite element analysis that internal use of bisphosphonate reduces strain of the cancellous bone inside vertebral body within one year, and notably decreases the region of high strain which is easy to break. Internal use of bisphosphonate improves the bone density distribution inside vertebral body, and strengthens the structure of load support of the spine. The structural improvement of spine leads to prevention of fracture.

Bone and Bones↗
PubMed2005

The transmission of stress to grafted bone inside a titanium mesh cage used in anterior column reconstruction after total spondylectomy: a finite-element analysis.

STUDY DESIGN: A finite-element study of posterior alone or anterior/posterior combined instrumentation following total spondylectomy and replacement with a titanium mesh cage used as an anterior strut. OBJECTIVES: To compare the effect of posterior instrumentation versus anterior/posterior instrumentation on transmission of the stress to grafted bone inside a titanium mesh cage following total spondylectomy. SUMMARY OF BACKGROUND DATA: The most recent reconstruction techniques following total spondylectomy for malignant spinal tumor include a titanium mesh cage filled with autologous bone as an anterior strut. The need for additional anterior instrumentation with posterior pedicle screws and rods is controversial. Transmission of the mechanical stress to grafted bone inside a titanium mesh cage is important for fusion and remodeling. To our knowledge, there are no published reports comparing the load-sharing properties of the different reconstruction methods following total spondylectomy. METHODS: A 3-dimensional finite-element model of the reconstructed spine (T10-L4) following total spondylectomy at T12 was constructed. A Harms titanium mesh cage (DePuy Spine, Raynham, MA) was positioned as an anterior replacement, and 3 types of the reconstruction methods were compared: (1) multilevel posterior instrumentation (MPI) (i.e., posterior pedicle screws and rods at T10-L2 without anterior instrumentation); (2) MPI with anterior instrumentation (MPAI) (i.e., MPAI [Kaneda SR; DePuy Spine] at T11-L1); and (3) short posterior and anterior instrumentation (SPAI) (i.e., posterior pedicle screws and rods with anterior instrumentation at T11-L1). The mechanical energy stress distribution exerted inside the titanium mesh cage was evaluated and compared by finite-element analysis for the 3 different reconstruction methods. Simulated forces were applied to give axial compression, flexion, extension, and lateral bending. RESULTS: In flexion mode, the energy stress distribution in MPI was higher than 3.0 x 10 MPa in 73.0% of the total volume inside the titanium mesh cage, while 38.0% in MPAI, and 43.3% in SPAI. In axial compression and extension modes, there were no remarkable differences for each reconstruction method. In left-bending mode, there was little stress energy in the cancellous bone inside the titanium mesh cage in MPAI and SPAI. CONCLUSIONS: This experiment shows that from the viewpoint of stress shielding, the reconstruction method, using additional anterior instrumentation with posterior pedicle screws (MPAI and SPAI), stress shields the cancellous bone inside the titanium mesh cage to a higher degree than does the system using posterior pedicle screw fixation alone (MPI). Thus, a reconstruction method with no anterior fixation should be better at allowing stress for remodeling of the bone graft inside the titanium mesh cage.

Aged, 80 and over↗
PubMed2005

Influence on spinal cord blood flow and function by interruption of bilateral segmental arteries at up to three levels: experimental study in dogs.

STUDY DESIGN: Segmental arteries were interrupted bilaterally at up to three levels to study the influence on spinal cord blood flow (SCBF) and function in dogs. OBJECTIVES: Considering the need to limit blood loss during surgery for spinal tumors, such as total en bloc spondylectomy, we studied the SCBF and function after experimental interruption of segmental arteries at up to three levels. SUMMARY OF BACKGROUND DATA: Interruption of bilateral segmental arteries at three consecutive levels (T11, T12, and T13) has reduced blood flow to the vertebral body of T12 by one fourth of the control flow, but effects on the spinal cord have not been determined. METHODS: SCBF was measured in spinal cord gray matter at T12 using a hydrogen clearance method after ligation of bilateral segmental arteries at 1 to three levels (T11, T12, and T13) in 6 dogs. Spinal cord function was evaluated by spinal cord evoked potentials, motor-evoked potentials, and neurologic assessment in 6 dogs. RESULTS: SCBF at T12 decreased to 92.4%, 87.8%, and 84.6% of control flow after ligation of bilateral segmental arteries at T12, T11 plus T12, and T11-T13, respectively. Spinal cord evoked potentials and motor-evoked potentials showed no significant changes in any dog after ligation at three levels. No neurologic degradation was observed in any dog. CONCLUSIONS: Interruption of bilateral segmental arteries at three levels did not damage spinal cord function in dogs, suggesting that in patients, preoperative embolization at three levels to reduce blood loss during surgery for spinal tumors would not compromise spinal cord function.

Animals↗
PubMed2005

Influence of acute shortening on the spinal cord: an experimental study.

STUDY DESIGN: Morphometric changes of the spinal cord and influence on spinal cord-evoked potentials and spinal cord blood flow and postoperative function of hind limbs were studied in various degrees of acute spinal column shortening in dogs. OBJECTIVES: To study the morphometric and physiologic effects of acute spinal column shortening on the spinal cord. SUMMARY OF BACKGROUND DATA: The technique of acute spinal column shortening is sometimes applied for correction of spinal deformity, total en bloc spondylectomy operation, or other diseases. However, safe limits and physiologic effects of acute spinal column shortening have not yet been described. METHODS: Total spondylectomy of T13 was performed in dogs after spinal instrumentation placed 2 levels above and 2 levels below the spondylectomy level. Spinal column was gradually shortened until the lower endplate of T12 contacted the L1 upper endplate (maximum of 20 mm). When any morphologic change of the dural sac or the spinal cord was observed, the length of shortening was measured. Spinal cord-evoked potentials were recorded on the exposed dura mater following epidural stimulation at the C7 level in 8 dogs. Spinal cord blood flow was measured during shortening in 6 dogs. Hindlimb function was evaluated 2 weeks after operation in 10 dogs. RESULTS: No morphometric changes occurred in the dural sac and the spinal cord until shortening of 7.2 +/- 1.7 mm (n = 6). From 7.2 +/- 1.7 to 12.5 +/- 1.1 mm shortening, the dural sac was deformed, whereas the spinal cord maintained its shape. Shortening more than 12.5 +/- 1.1 mm buckled the dural sac, and the spinal cord kinked itself and was compressed by the buckled dura in its concave side (n = 6). No changes could be detected in spinal cord-evoked potentials in 5 or 10 mm of shortening. Spinal cord-evoked potential changes were recorded in the 2 of 6 dogs with 15 mm of shortening. At 20 mm of shortening, spinal cord-evoked potential abnormality was observed in 4 of 6 dogs. At shortening of 5, 10, 15, and 20 mm, spinal cord blood flow was 146 +/- 10%, 160 +/- 21%, 102 +/- 17%, and 93 +/- 7% of the control (29.2 +/- 7.9 mL/100 g/min, n = 6), respectively. All 3 dogs with 10 mm ofshortening had normal hindlimb function 2 weeks after operation. One of the 3 dogs with 15 mm of shortening had paraparesis. Three of the 4 dogs with 20 mm of shortening had also paraparesis after operation. CONCLUSIONS: Acute spinal column shortening can be characterized into 3 phases. Phase 1, safe range: occurred during shortening within one-third of the vertebral segment and is characterized by no deformity of the dural sac or the spinal cord. Phase 2, warning range: occurred during spinal shortening between one-third and two-thirds of the vertebral segment and is characterized by shrinking and buckling of the dural sac and no deformity of the spinal cord. Phase 3, dangerous range: occurred after shortening in excess of two-thirds of the vertebral segment and is characterized by spinal cord deformity and compression by the buckled dura. Spinal shortening within the safe range increases spinal cord blood flow.

Animals↗
PubMed2005

Osteoblast lineage properties in giant cell tumors of bone.

BACKGROUND: Giant cell tumors of bone (GCTs), among the most common primary bone tumors, are characterized by the formation of abundant osteoclast-like multinucleated giant cells (MNCs). It is not yet clear about the origin of GCTs and which cells in the lesion are the true neoplastic component. Several recent reports suggested that MNCs are osteoclasts induced by stroma-like tumor cells expressing the ligand for receptor activator of NF-kappaB (RANKL), which is a membrane-bound osteoclast differentiation factor. This hypothesis suggests an osteoblast lineage origin of GCTs, although it has long been speculated about GCTs being of mesenchymal stem cell (MSC) origin. METHODS: We investigated the expression of osteoblastic differentiation markers in 10 human GCTs by reverse transcription-polymerase chain reaction and immunohistochemistry. We also performed osteoblastic and adipogenic differentiation assays using cultured cells derived from surgically resected lesions to estimate the stem cell-like properties. RESULTS: GCTs and derived stromal cells expressed many osteoblast lineage marker genes, such as collagen type I, bone sialoprotein, core binding factor a-1, and osteocalcin. Instead of stable expression of mRNA, osteocalcin was not detected among the proteins. The tumor-derived cultures showed osteoblastic but not adipogenic differentiation capability. These findings strongly suggest that GCTs are of osteoblast lineage origin. CONCLUSIONS: Our results indicated that GCTs expressed many osteoblastic markers and showed properties of pre-osteoblast-like cells rather than those of MSCs. These observations may provide some insight into the mechanisms of disease progression and the origin of GCTs.

Adolescent↗
PubMed2004

Interruption of the bilateral segmental arteries at several levels: influence on vertebral blood flow.

STUDY DESIGN: The effect of ligation of the bilateral segmental arteries at the levels of T11, T12, and T13 on blood flow of the T12 vertebra was studied in a dog model. OBJECTIVES: To determine the reduction of the vertebral blood flow resulting from interruption of bilateral segmental arteries at one to three vertebral levels. SUMMARY OF BACKGROUND DATA: Intraoperative hemorrhage can be sometimes massive in patients with hypervascular spinal tumors, especially in radical resection such as total en bloc spondylectomy. The recent development of new embolization techniques ensures more aggressive, more extensive, and safer preoperative embolization for spinal tumors. METHODS: The blood flow of the T12 vertebra of 12 female dogs was measured after ligation of the bilateral segmental arteries at one to three levels, including the T12. Spinal cord evoked potentials were recorded in this procedure. Spinal angiography using a silicon compound was performed on another 10 dogs after clipping and section of the bilateral segmental arteries. RESULTS: The blood flow of the T12 vertebra decreased to 70.13 +/- 6.37% of the control value after ligation of the bilateral segmental arteries of T12, to 46.48 +/- 8.97% after ligation of the bilateral segmental arteries of T12 and either T11 or T13, to 24.11 +/- 8.31% after ligation of T11, T12, and T13, respectively. The angiogram after ligation and section of T12 and the two levels including T12 showed thick and clear contrast medium in the cut distal ends of the T12 segmental arteries. After interruption at three levels (T11, T12, and T13), however, the cut distal ends of the T12 segmental arteries were seen thin and faint on the angiogram. No significant changes occurred in spinal cord evoked potentials after ligation of the segmental arteries at three levels in all six dogs. CONCLUSION: Interruption of the bilateral segmental arteries at three levels, one target vertebra and the two adjacent vertebrae, reduced the blood flow of the target vertebra to one fourth of the control value in the lower thoracic spine in dogs. This result suggests that preoperative embolization at three levels, the levels of the tumor vertebra and the adjacent vertebrae above and below it, may reduce intraoperative hemorrhage effectively during total en bloc spondylectomy for hypervascular spinal tumors.

Angiography↗
PubMed2004

Double-chelation-assisted Rh-catalyzed intermolecular hydroacylation between salicylaldehydes and 1,4-penta- or 1,5-hexadienes.

Intermolecular hydroacylation between salicylaldehydes 1, 26-40 and 1,4-penta- or 1,5-hexadienes 4-13 by Rh-catalyst proceeded under mild reaction conditions to give a mixture of iso- and normal-hydroacylated products 14-25, 41-55, and 57-60. In the hydroacylation reaction, chelation of both salicylaldehyde and diene to the Rh-complex plays a crucial role. The ratio of iso- and normal-hydroacylated products could be regulated by the addition of salicylic acid or amines. The effects of various Rh-complexes, solvents, and additives were examined, and the plausible mechanisms of the catalytic cycle were proposed on the basis of the deuterium-labeling salicylaldehyde experiments.

Journal Article↗
PubMed2004

Nationwide survey on complications of spine surgery in Japan.

The Japan Spine Research Society carried out a nationwide survey on complications of the spine, enrolling a total of 16 157 patients who had undergone spine surgery in 196 institutes in the 1-year period from January to December 2001. Diseases, surgical procedures, and complications were surveyed in detail. Forty-nine percent of patients were aged 60 years or older, which was remarkably increased in comparison with the percentage reported by the 1994 survey (37.3%). The number of cases with degenerative spinal diseases comprised 78.2% of the total number of spine surgery cases. The percentage of patients with stenosis was the greatest (38.5%), reflecting the increase in the elderly population undergoing spine surgery. Spinal instrumentation was used with 5497 patients (34.0%). The frequency of its use was much greater than that reported in 1994 (27.0%). The pedicle screw was the most frequently used instrument (54.6%). The use of spinal instrumentation greatly increased for spinal deformity, trauma, and tumors. Posterior lumbar interbody fusion has been increasingly used in cases of lumbar degenerative disease. Complications of spinal surgery were reported in 1383 patients (8.6%). The incidence of complications associated with instrumentation surgery was 12.1%, being twice as much as that associated with noninstrumentation surgery (6.8%).

Adolescent↗
PubMed2003

Vertebral body osteonecrosis without vertebral collapse.

STUDY DESIGN: A case of idiopathic focal vertebral body osteonecrosis without vertebral collapse is reported. OBJECTIVES: To report a rare case of focal vertebral osteonecrosis and to clarify the features of imaging studies. SUMMARY OF BACKGROUND DATA: There are no previous reports describing focal vertebral body necrosis without collapse in the literature. METHODS: A case report and literature review are presented. RESULTS: Imaging studies demonstrated: 1) sclerotic change on computed tomography scan; 2) low intensity on T1, high intensity on T2 with clear margin, and no gadolinium enhancement on magnetic resonance imaging; and 3) no uptake on bone scan. Histologic examination revealed empty lacunas, fatty necrosis with vacuolar degeneration, and cell debris compatible with bone marrow necrosis. CONCLUSION: Vertebral body osteonecrosis must be considered a possible diagnosis of patients presenting with low intensity on T1, high intensity on T2 with clear margin, and no gadolinium enhancement on magnetic resonance imaging.

Adult↗
PubMed2003

Adjacent segment motion after a simulated lumbar fusion in different sagittal alignments: a biomechanical analysis.

STUDY DESIGN: An in vitro biomechanical study of adjacent segment motion (at L3-L4 and L5-S1) after a simulated lumbar interbody fusion of L4-L5 in different sagittal alignments was carried out. OBJECTIVES: To test the hypothesis that an L4-L5 fixation in different sagittal alignments causes increased angular motion at the adjacent levels (L3-L4 and L5-S1) in comparison with the intact spine. SUMMARY OF BACKGROUND DATA: Clinical experience has suggested that lumbar fusion in a nonanatomic sagittal alignment can increase degeneration of the adjacent levels. It has been hypothesized that this is the result of increased motion at these levels; however, to the authors' knowledge no mechanical studies have demonstrated this. METHODS: Eight fresh human cadaveric lumbar spines (L3-S1) were biomechanically tested. Total angular motion at L3-L4 and L5-S1 under flexion-extension load conditions (7-Nm flexion and 7-Nm extension) was measured. Each specimen was tested intact, and then again after each of three different sagittal fixation angles (at L4-L5): (1) in situ (21 degrees lordosis), (2) hyperlordotic (31 degrees lordosis), and (3) hypolordotic (7 degrees lordosis). The simulated anterior/posterior fusion was performed at L4-L5 with pedicle screws posteriorly, vertebral body screws anteriorly, and an interbody dowel. RESULTS: The averaged values for flexion-extension motion at L3-L4 were as follows: intact specimen 2.0 degrees, in situ fixation 4.0 degrees, hyperlordotic fixation 1.7 degrees, hypolordotic fixation 6.5 degrees. The averaged values for flexion-extension motions at L5-S1 were as follows: intact specimen 2.3 degrees, in situ fixation 2.6 degrees, hyperlordotic fixation 3.6 degrees, hypolordotic fixation 2.9 degrees. CONCLUSION: Hypolordotic alignment at L4-L5 caused the greatest amount of flexion-extension motion at L3-L4, and the differences were statistically significant in comparison with intact specimen, in situ fixation, and hyperlordotic fixation. Hyperlordotic alignment at L4-L5 caused the greatest amount of flexion-extension motion at L5-S1, and the difference was statistically significant in comparison with intact specimen but not in situ fixation or hypolordotic fixation.

Aged↗
PubMed2003

Reconstruction after total sacrectomy using a new instrumentation technique: a biomechanical comparison.

STUDY DESIGN: The stresses exerted on the instrumentation and adjacent bone were evaluated for three reconstruction methods after a total sacrectomy: a modified Galveston reconstruction (MGR), a triangular frame reconstruction (TFR), and a novel reconstruction (NR). OBJECTIVE: To perform finite-element analysis of reconstruction methods used after a total sacrectomy. SUMMARY OF BACKGROUND DATA: When a sacral tumor involves the first sacral vertebra, a total sacrectomy is necessary. It is mandatory to reconstruct the continuity between the spine and the pelvis after a total sacrectomy. However, no previous reports have described a biomechanical study of the reconstructed lumbosacral spine. METHODS: A finite-element model of the lumbar spine and pelvis was constructed. Then three-dimensional MGR, TFR, and NR models were reconstructed, and a finite-element analysis was performed to account for the stresses on the bones and instrumentation. RESULTS: With excessive stress concentrated at the spinal rod in MGR, there is a strong possibility that the rod between the spine and the pelvis may fail. Although there was no stress concentration on the instruments in TFR, excessive stress on the iliac bones around the sacral rod was above the yield stress of the iliac bone. Such stress may cause a loosening of the sacral rod from the iliac bone. In NR, excessive stress concentration was not detected in the rod or the bones. This reconstruction has a low risk of instrument failure and loosening. CONCLUSIONS: If the patient were to stand or sit immediately after MGR or TFR instrumentation, failure or loosening may occur. The NR has a low risk of instrument failure and loosening after a total sacrectomy.

Adult↗
PubMed2003

Double-chelation-assisted Rh-catalyzed intermolecular hydroacylation.

[reaction: see text] Rh-Catalyzed intermolecular hydroacylation between salicylaldehydes and 1,5-hexadienes proceeded under remarkably mild reaction conditions to afford a mixture of iso- and normal-hydroacylated products in good yields. The experiments using deuterated salicylaldehyde-d revealed that "double chelation" of salicylaldehyde and 1,5-hexadiene to Rh-complex played vital roles in the catalytic cycle of intermolecular hydroacylation.

Journal Article↗