Tetsuya Kinoshita

Shinshu University, Shonai, Nagano, Japan

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Publications (21)47.9 Total impact

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    ABSTRACT: We examined the urinary disturbances in 56 consecutive patients with cervical compressive myelopathy using the latest International Continence Society classification. Of the 56 patients with cervical compressive myelopathy, 29 (52%) had some urinary subjective complaints, whereas the remaining 27 (48%) had none. Urologic examination indicated that 8 of these 29 (28%) patients with urinary complaints had urologic disorders other than neurogenic bladder. Of the remaining 21 patients, only 6 (25%) were judged to have neurogenic bladder on urodynamic study. Urodynamic study may be of limited value in diagnosing urinary disturbance in cervical myelopathy. Further, four cases (83%) showed underactive bladder activity in voiding phase, and only one case (17%) showed overactive bladder activity in filling phase. These results were contrary to those of previous studies indicating that cervical compressive myelopathy is associated with overactive bladder activity in filling phase. There were no significant differences in motor or sensory Japanese Orthopedic Association scores between the patients with and without urinary complaints. However, the patients with urinary complaints had significantly longer durations of myelopathy and delayed motor evoked potential latencies than those without urinary complaints. After surgery, 19 of the 21 (90%) patients with urinary complaints showed recovery from urinary disturbance. Operations in patients with cervical myelopathy were also effective against urinary disturbance. Urinary complaints may be an indication for surgical treatment despite the results of urodynamic study.
    No preview · Article · Sep 2005 · Journal of Spinal Disorders & Techniques
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    ABSTRACT: Previous reports have described magnetic resonance imaging (MRI) findings alleged to be specific for vertebral fractures caused by malignant lesions. Using such findings for differential diagnosis is often difficult, especially during the early phase of the fracture. With the relative inaccuracy of any single imaging finding, a validated scoring system based on a combination of imaging findings might lead to enhanced diagnostic accuracy. The purpose of this study was to establish a diagnostic scoring system for discriminating osteoporotic vertebral fractures from those caused by malignant tumors on the basis of MRI and computed tomography (CT) findings. Ten MRI and CT scan findings of 57 osteoporotic vertebral fractures and 43 neoplastic fractures were retrospectively evaluated for their ability to discriminate between malignant and benign vertebral fractures. The following four MRI and two CT findings were selected as the basis for the scoring system: pedicle or other posterior element involvement; extension into the paravertebral region; preservation of normal bone marrow signal; a continuous black line representing the posterior vertebral body margin on T2-weighted MRI images; osteolytic destruction; and distinct fracture lines on CT. By combining the findings common to MRI and CT scans of vertebral fractures, a simple scoring system was devised. This scoring system was found to enhance the accuracy of imaging diagnosis of fractures caused by benign or malignant spinal lesions.
    No preview · Article · Aug 2005 · Journal of Orthopaedic Science
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    ABSTRACT: Nine patients with severely destructive spondyloarthropathy and marked neurologic deficits associated with dialysis-related amyloidosis underwent posterior decompression and fusion by means of instrumentation at our institute. All patients showed segmental kyphosis, six patients vertebral ankylosis, and eight patients spondylolisthesis. Spondylolisthesis at two levels was noted in three patients. Of the 11 levels of spondylolisthesis in all, 9 were proximally adjacent and 2 were distally adjacent to vertebral ankylosis. All patients underwent posterior decompression and multisegment fusion with autogenous iliac bone. From three to five spinal segments were fixed. Seven patients underwent posterior fusion by means of a pedicle or lateral mass screw between levels C3 and C7, one patient between C3 and C6, and one between C3 and T1. The clinical rate of improvement at the final follow-up was 74.3%. Though complete stability could not be achieved in three patients, the results were rated as good. No postoperative neurologic deterioration has been observed in this series, nor did any patients die immediately after surgery or during the postoperative follow-up period. As anterior long-span surgery might be too invasive for hemodialysis patients, we think that posterior decompression and fusion may well be a reasonable and effective strategy for severe hemodialysis-associated cervical spondyloarthropathy with neurologic deficits. To achieve complete stability, 360 degrees fusion with both anterior and posterior fixation with instrumentation may be required for these patients.
    No preview · Article · Mar 2005 · Journal of Spinal Disorders & Techniques
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    ABSTRACT: We investigated the enhancement of new bone |formation elicited ectopically by recombinant human bone morphogenetic protein-2 (rhBMP-2), using parathyroid hormone (PTH) and a phosphodiesterase inhibitor (PDEi), pentoxifylline (PTX), in an animal model. Collagen sponge sheet discs containing rhBMP were implanted onto the back muscles of mice. PTX alone (200 mg/kg body weight [BW]), PTH(1-34) (10 microg/kg BW), PTX plus PTH (200 mg/kg BW and 10 microg/kg BW, respectively), or vehicle (control) were injected subcutaneously daily for 3 weeks after implantation. At the end of this period, rhBMP-2-induced ectopic ossicles were harvested from each group of animals. Ossicles from the PTX-treated group were significantly larger in size, with unchanged bone mineral density (BMD), as compared with the ossicles from the controls. In contrast, the ossicles from the PTH-treated group had significantly higher BMD, but showed no difference in size when compared with those from the control animals. The ossicles of the PTX + PTH treatment group were significantly larger than those of the control and PTH treatment groups. In addition, the BMD of the harvested tissues from the PTX + PTH treatment group was signifi-cantly higher than that of tissues from the control and PTX treatment groups. Although the calcium content of ossicles was significantly higher in the PTX-, PTH-, and PTX + PTH-treated groups than in the control group, the Ca content of ossicles from the PTH + PTX-treated group was highest (two times that of controls), followed by the PTH- and PTX-treated groups.
    Full-text · Article · Feb 2004 · Journal of Bone and Mineral Metabolism
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    ABSTRACT: The purpose of this study was to achieve spinal fusion in the absence of bone graft material using a new, injectable, and semi-liquid synthetic polymer (polylactic acid polyethylene glycol [PLA-PEG] block copolymer) containing recombinant human bone morphogenetic protein-2 (rhBMP-2). Twenty-seven skeletally mature beagles underwent anterior thoracic spinal fusion at T9-T10. Group I (n = 9) was injected with 1 mL of PLA-PEG block copolymer carrier alone into space under the vertebral pleura and the anterior longitudinal ligament. Group II (n = 9) was injected with 1 mL of PLA-PEG carrier containing 500 microgram of rhBMP-2. Group III (n = 9) was injected with 1 mL of PLA-PEG carrier containing 1000 microgram of rhBMP-2. In the Group I animals, no evidence of new bone formation was noted at the implanted sites both radiographically and histologically. In contrast, all of the nine animals in Group III showed new bone formation in 12 weeks, and four of the nine animals in Group II showed bony mass at the injected sites. However, vertebral bony fusion was incomplete despite the significant amount of new bone formation in both groups that showed new bone formation. In addition to resulting in improvements in the surgical procedure, injection of rhBMP-2 and a synthetic polymer is useful for bone formation for spinal fusion.
    No preview · Article · May 2003 · Journal of Spinal Disorders & Techniques
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    ABSTRACT: A retrospective study of the outcomes of multilevel anterior decompression and interbody fusion for cervical myelopathy due to ossification of the posterior longitudinal ligament (OPLL) was performed to both investigate the long-term results and assess the cause of late deterioration. Twenty-seven patients (mean age, 58.1 years) underwent this procedure and were followed for at least 5 years. The severity of the clinical symptoms was described using the scoring system for cervical myelopathy proposed by the Japanese Orthopaedic Association (JOA score). The average preoperative JOA score was 7.7, and the score at final follow-up was 13.4 with a recovery rate of 62.0%. A delayed deterioration was attributed to a thoracolumbar lesion other than a compromising alteration of the cervical spine. Consequently, this method of treatment for OPLL could stop the progress of ossification and keep a physiological cervical alignment and thus provide good long-term results.
    No preview · Article · Apr 2003 · Journal of Clinical Neuroscience
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    ABSTRACT: The authors sought to identify treatment-related factors that influenced survival after surgical treatment for metastatic spinal tumors and to evaluate the relationship between survival and postoperative ambulation time as a factor related to quality of life. The medical records of 81 patients with metastatic spinal tumors who underwent palliative surgery at the study institution were assessed. Univariate analysis for factors influencing survival used the Kaplan-Meier log rank statistic and multivariate analysis used the Cox proportional hazards model. The Spearman correlation test was used to analyze the relationship between postoperative ambulation and survival time. The patients had a median age of 59.9 years and a median survival of 10.6 months after surgery. For patients, postoperative ambulatory median survival was 16.5 months and median ambulation time was 13.8 months. By univariate analysis, anatomic site of the primary tumor, postoperative ambulation, and combined adjuvant therapy (chemotherapy plus radiotherapy) were associated with prolonged survival (P < 0.05). Multivariate analysis identified primary site and postoperative ambulatory function as independent predictors of prolonged survival (P < 0.0001). Significant correlations were found between ambulation time and survival time of patients who were able to walk after surgery (P < 0.0001), even in patients with liver (P < 0.05) or lung carcinoma (P < 0.05). The anatomic site of primary carcinoma and postoperative ambulation were associated with longer survival after palliative surgery for metastatic spinal tumor. When ambulation is attained after surgery, it can be preserved until late in remaining life even when the primary tumor is unfavorable. Palliative surgery for spinal metastasis can improve the quality and quantity of life.
    Preview · Article · Jan 2003 · Cancer
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    ABSTRACT: We investigated the effects of instrumentation on postoperative inflammatory reaction and identified standard changes in serum cytokine concentrations after spinal surgery. Pro-inflammatory cytokines [interleukin (IL)-6 and IL-8] and anti-inflammatory cytokines [IL-10, IL-1 receptor antagonist (ra), and soluble tumor necrosis factor receptors (sTNF-R) I and II] were assayed in serum from seven patients with lumbar spinal posterior decompression, six with spinal decompression and posterolateral fusion without instrumentation and seven with spinal decompression and posterolateral fusion with instrumentation. All cytokines after spinal instrumentation increased significantly more than in other groups on postoperative days 0 and 1. Seven days after SI, IL-6, -8, and -10 had normalized, but IL-1ra and sTNF-RI and sTNF-RII remained elevated. Both pro-inflammatory and anti-inflammatory cytokines were enhanced by implants in the acute phase, whereas only anti-inflammatory cytokines were enhanced by instruments in the subacute phase.
    No preview · Article · Sep 2002 · Journal of Spinal Disorders & Techniques
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    ABSTRACT: The cyclic monophosphate nucleotides (cyclic adenosine monophosphate [cAMP] and cyclic guanosine monophosphate [cGMP]) are found ubiquitously in mammalian cells and act as second messenger transducers to effect the intracellular actions of a variety of hormones, cytokines, and neurotransmitters. In turn, these nucleotides also modulate the signal transduction processes regulated by a range of cytokines and growth factors. Previously, we have reported that pentoxifylline, a nonselective phosphodiesterase (PDE) inhibitor, can promote osteoblastic differentiation by elevating intracellular cAMP levels and, consequently, enhance bone formation in vivo and in vitro. In this study, reverse-transcription polymerase chain reaction (RT-PCR) analysis of the osteoblastic cell lines, MC3T3-E1 and ST2 revealed the presence of PDE1, PDE2, PDE3, PDE4, PDE7, PDE8, and PDE9. We examined the effect of selective inhibitors for a respective PDE isozyme on the capacity of bone morphogenetic protein 4 (BMP-4)-induced alkaline phosphatase (ALP) activity, a cellular differentiation marker, in cells with osteogenetic potential. The results indicate that selective inhibitors for PDE2, PDE3, and PDE4 enhanced the BMP-4-induced ALP activity in a dose-dependent manner in ST2 cells but not in MC3T3-E1 cells. Northern blot analysis also revealed that the selective inhibitors for PDE2, PDE3, and PDE4 enhanced the levels of expression of messenger RNAs (mRNAs) of ALP, osteopontin (OP), and collagen type I in ST2 cells but not in MC3T3-E1 cells except for the treatment with PDE4 inhibitor. Given these data, we conclude that PDE isozymes are involved in the modulation of osteoblastic differentiation mainly at an early stage. Additionally, selective inhibitors for PDE2, PDE3, and PDE4 appear to promote the differentiation of osteogenic precursor cells toward an osteoblastic phenotype.
    Full-text · Article · Mar 2002 · Journal of Bone and Mineral Research
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    ABSTRACT: It is sometimes difficult to determine the appropriate surgical site in patients with thoracic myelopathy with diffuse or multisegmental lesions. To solve this problem, a magnetic stimulation study was carried out. Seven patients with myelopathy and 10 healthy control subjects were examined. Transcranial magnetic stimulation was applied and the motor evoked potentials (MEPs) of the intercostal muscles were recorded. The MEP latencies for the two groups were then compared. In patients with thoracic myelopathy, the MEP latencies caudal to the lesion were more extended than those of the control subjects. This method could identify the levels at which myelopathy originates in patients with a radiologically visible lesion. This method has the potential to be used for deciding the surgical site at the level responsible for myelopathy in cases with multiple or diffused compression.
    No preview · Article · Nov 2001 · Journal of Spinal Disorders
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    ABSTRACT: The erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and body temperature were measured prospectively in patients after two types of spinal surgery without complications and three cases of infection after spinal instrumentation surgery. To investigate the effects of instrumentation on postoperative inflammatory reaction, and to describe early detection of postoperative wound infection. In thoracic and abdominal surgery as well as hip arthroplasty, C-reactive protein has proved more valuable than erythrocyte sedimentation rate for early detection of postoperative infectious complications. It has not yet been established, however, how inflammatory parameters change after surgery when spinal instruments have been inserted into the body. For this study, two groups of patients were examined: a control group that underwent spinal decompression surgery without instrumentation (n = 36) and another group that underwent spinal decompression and fusion surgery with spinal instrumentation (n = 37). The erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and body temperature were recorded 1 day before surgery and on days 0 to 4, 7, 11, 14, 21, 28, and 42 after surgery. Inflammatory indexes (i.e., C-reactive protein, erythrocyte sedimentation rate, white blood cell count, and body temperature) were significantly higher for the surgery with instrumentation than for the spinal decompression surgery without instrumentation. Multiple regression analysis showed that C-reactive protein and erythrocyte sedimentation rate peaks significantly correlated with the use of instrumentation (C-reactive protein: P = 0.000257, erythrocyte sedimentation rate: P = 0.000132). In the patients with infection after spinal instrumentation surgery, C-reactive protein, white blood cell count, and body temperature started to increase again 4 to 11 days after surgery. The elevation of erythrocyte sedimentation rate levels was prolonged. Erythrocyte sedimentation rate and C-reactive protein display a significantly higher reaction after spinal surgery with instrumentation. Renewed elevation of C-reactive protein, white blood cell count, and body temperature after postoperative days 4 to 7 may be a critical sign of postoperative infection.
    No preview · Article · Sep 2001 · Spine
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    ABSTRACT: Two cases of eosinophilic granuloma (EG) of the spine associated with neurological deficits are presented. The patients were treated conservatively by using external fixation with a brace as well as bed rest. Neurological deficits and pain diminished and finally disappeared as the tumor mass decreased in size, as seen on magnetic resonance (MR) imaging. During the 5-year follow-up period no recurrence of the tumors was detected on MR images. Surgical treatment for spinal EG in children presenting with typical vertebra plana is not recommended except for those with severe or progressive palsy and for those in whom the disease requires differential diagnosis.
    No preview · Article · Nov 2000 · Journal of Neurosurgery
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    ABSTRACT: We used a commercially available computer-assisted image-guidance system for cervical pedicle screw insertion in both the laboratory and in a preliminary clinical setting. Nine plastic cervical spine models (C2-C7) were used in the laboratory test. The StealthStation was used to create the preoperative plan for each screw such that it would be inserted down the center of the pedicle, parallel to the long axis. Using a light-emitting diode-equipped drill guide, 2-mm holes were drilled in 108 pedicles. A total of 108 pedicle holes were drilled. The mean trajectory deviation from the surgical plan in the axial plane was 1.7+/-1.7 degrees (range, 0 to 8 degrees), and the mean deviation of the position of the hole was 1.7+/-0.6 mm (range, 0.1 to 2.9 mm). Eighty-three drill holes (76.9%) were contained within the pedicles, whereas partial cortical perforation was noted in 25 pedicles (23.1%). In the clinical setting, 36 cervical pedicle screws were inserted in nine patients using the image-guided system. Within the limits of imaging artifact, all 36 pedicle screws appear to have been inserted accurately by postoperative computed tomographic examination. No neurologic or vascular complications were encountered.
    No preview · Article · Jul 2000 · Journal of Spinal Disorders
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    ABSTRACT: Desmoplastic fibroma is a relatively uncommon tumor and rarely involves the spine. The authors describe a 20-year-old woman with a thoracic epidural desmoplastic fibroma treated by complete resection and posterior spinal fusion. Four years after surgery, neither the tumor nor clinical symptoms have recurred. Thus, complete resection is considered necessary to treat this tumor.
    No preview · Article · Jul 2000 · Journal of Spinal Disorders
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    ABSTRACT: A report on the results of animal experiments in which the authors' new system that enables the anterior correction and fixation of thoracic spinal deformity by use of a thoracic endoscope and small incisions was used. The results suggest that the new approach involving thoracoscopic anterior correction and fusion for thoracic spinal deformity could be adapted successfully for the clinic. To develop a new system that enables the anterior correction and fixation of thoracic spinal deformity by use of a thoracic endoscope and small incisions. Anterior correction and fusion through open thoracotomy have been applied mainly for thoracic scoliosis because this approach provides effective correction with short fusion. However, excellent visualization of the spine during thoracic surgical procedures led to the development of thoracoscopic spine surgery. Therefore, the authors postulated that a thoracoscopic approach could allow not only discectomy but also correction and fusion of the deformed thoracic spine in a single surgical event. The vertebral columns and attached thoracic walls were dissected from fresh porcine cadavers and used in the experimental surgery to evaluate the new system. As a next step, thoracoscopic surgery using this new system was performed on four or five vertebrae of five live pigs with an average weight of 50 kg. Initially, the discs and rib heads were removed through the thoracic wall. For each vertebra, a screw connected to a shaft used as a screw holder was inserted through the thoracic wall in a posterior to anterior direction. Each shaft then was linked outside the body to an outrigger. This outrigger was used to both create and restore scoliosis. A rod then was introduced through the thoracic wall and fixed to the screw heads. The animal experiments clearly showed that it was possible to change the Cobb angles of the spine through the use of the outrigger apparatus. In cadaver experiments, it was possible to create scoliosis and re-store it by 25 degrees to 35 degrees. Also, surgery on live pigs resulted in scoliosis of approximately 30 degrees, which means approximately 5 degrees to 10 degrees for each disc space. The procedures used also demonstrated that it was possible to fix a rod, introduced into the pleural cavity through a port, with screw heads. The use of this system successfully changed the Cobb angle of the spine, which suggests that its use should make it possible to correct spinal deformities. This apparatus also succeeded in fixing the rods in the screw heads, which raises the possibility of its use in spinal fixation. The authors believe that this apparatus could be adapted successfully for clinical use. Studies currently are under way in clinics using the new system.
    No preview · Article · May 2000 · Spine
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    ABSTRACT: Anterior instrumentation is recommended to correct idiopathic thoracolumbar or lumbar scoliosis through short fusion within the major curve. Only a few reports exist of anterior surgical correction for thoracic scoliosis. This study assessed the results of Zielke instrumentation for thoracic curve and analyzed the three-dimensional correction of deformity, especially correction of the uninstrumented compensatory curve. Seventeen patients, who had undergone selective thoracic correction and fusion using the Zielke procedure to treat thoracic scoliosis, had been followed for at least 3 years. Three-dimensional correction was evaluated radiographically. Furthermore, three-dimensional back deformities were evaluated using a topographic body scanner. Twelve patients with a single thoracic curve and five with a double curve were all female, with a mean age of 14.6 years. The preoperative main thoracic curve was 54.8 degrees +/- 10.5 degrees (range, 40-78 degrees), and it was 23.8 degrees +/- 10.5 degrees (range, 7-40 degrees) at the final follow-up examination (p < 0.0001). The average correction rate of the main curves was 56.6%. By correcting the thoracic curve, the upper and lower compensatory curves were corrected spontaneously without surgical instrumentation, with average correction rates of 45.1% and 50.2%, respectively. The average correction loss of the main curve was 2.3 degrees. The hump angle measured using a topographic body scanner decreased from 12.8 degrees +/- 4.5 degrees to 8.4 degrees +/- 4.3 degrees after surgery (p = 0.0001). Of the three patients in whom the rod broke up, only one showed a correction loss of 10 degrees; however, bony fusion was obtained. Anterior short fusion for thoracic scoliosis appears to offer significant correction, stabilization, and spontaneous correction of the compensatory lumbar curve without limiting lumbar motion.
    No preview · Article · Dec 1999 · Journal of Spinal Disorders
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    ABSTRACT: Posterolateral lumbar spinal fusion with use of recombinant human bone morphogenetic protein 2 (rhBMP-2) was tested in rabbits by implanting composites of rhBMP-2 and collagen carrier. To examine the bone-formation-inducing activity of rhBMP-2 and find the optimal amount of rhBMP to add to a collagen carrier to constitute bone-formation-inducing implants to be substituted for bone graft in posterolateral spinal fusion in rabbits. In animal models, rhBMP-2--impregnated collagen has been successfully used for posterolateral spinal fusion, indicating that it is a potential substitute for the autogenous corticocancellous bone graft currently used most routinely in posterolateral lumbar spinal fusion. Nine rabbits were divided into three equal groups. The bilateral L4-L5 transverse processes were exposed, and collagen strips impregnated with rhBMP-2 (10, 50, or 200 micrograms) were placed on the left transverse processes, and collagen strips alone were inserted on the right. All rabbits were killed 24 weeks after surgery. The implanted sites were assessed for new bone formation and bony fusion by radiography and histologic examination. New bone formation was noted in intertransverse spaces on the left side of all rabbits except one (10 micrograms rhBMP-2). Twelve weeks after implantation, no new bone formation was seen on the right side of all animals. The newly formed bone masses were significantly larger in the 50-microgram and 200-microgram rhBMP-2 groups than in the 10-microgram rhBMP-2 group (P < 0.01), but there was no significant difference between bone formation in the 50-microgram and 200-microgram groups (P = 0.647). The rhBMP-2/collagen composite implant was an effective bone graft substitute for achieving posterolateral spinal fusion. When combined with a collagen carrier, the optimal rhBMP-2 dose for achieving posterolateral spinal fusion seemed to be approximately 50 micrograms per segment in rabbits.
    No preview · Article · Aug 1999 · Spine
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    ABSTRACT: To screen a potential risk factor for femoral neck fracture, we characterized lumbar vertebral fractures in 120 patients with femoral neck fractures (19 men, 101 women; mean age, 78.7 years) by investigating the frequency of patients with lumbar vertebral fracture, the number of vertebral fractures per patient, and the severity of deformity of the fractured vertebral bodies. These findings were compared with data gathered from a population of age- and sex-matched control patients (20 men, 89 women; mean age, 77.6 years) who had no evidence of femoral neck fracture. The heights of the anterior and posterior walls together with the midpart of the lumbar vertebrae were measured on lateral radiographs to identify fractures. The extent of height loss in the fractured vertebrae was calculated for each group. The incidence of patients with vertebral compression fractures was significantly higher in the femoral neck fracture group than in the control group (65.0% vs 41.1%). In terms of age, the difference in the incidence of vertebral fractures in the two groups was greater in the less aged (60–79 years old) than in the more aged (>80 years old) population. The mean number of lumbar vertebral fractures was also significantly greater in the femoral neck fracture group than in the control group (1.59 ± 1.39 vs 0.75 ± 1.19; P < 0.001). The incidence of more deformed vertebral fractures, which were defined as a vertebral height loss of more than 50%, was also significantly higher in the group with femoral neck fracture than in the control group (23.0% vs 7.3%). Based on these results, we concluded that multiple and more severely deformed vertebral fractures might represent a high risk for femoral neck fracture, particularly in patients less than 79 years of age. Care measures that encompass fall prevention and protection of proximal femurs in addition to drug therapy for osteoporosis should be recommended to individuals in this category.
    No preview · Article · Jul 1999 · Journal of Bone and Mineral Metabolism
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    ABSTRACT: A new dorsolateral decompressive procedure involving a unilateral approach has been devised for the treatment of cervical compressive myelopathy. In this operation, the posterior spinal elements of the contralateral side are not disturbed, and thus, postoperative deformity of the cervical spine can be avoided. Following decompressive surgery via the unilateral approach, the cervical spine was kept more stable compared with the results obtained after wide laminectomy or other expansive laminoplasty procedures. Twenty-six patients underwent dorsolateral decompressive surgery, and the patients' clinical and radiological results were examined during the follow-up period to evaluate neurological function and postoperative deformities of the cervical spine. The underlying conditions for myelopathy were cervical spondylosis (19 patients), ossification of posterior longitudinal ligament (three patients), and ossification of yellow ligament (four patients). The follow-up period ranged from 6 to 110 months (average 35.5 months). Functional recovery, which was rated by using the Japanese Orthopaedic Association scoring system, was an average of 56% in all patients (100% being equal to full recovery). The recovery rate was compatible with those attained after other expansive laminoplasty procedures. Radiographically, progression to swan-neck or kyphotic deformity was not observed in any patient. No postoperative spinal instability was noted. Based on computerized tomography myelograph evaluation, the average transectional area of the dural tube at the C4-5 level was expanded from 122 mm2 to 169 mm2, and the transectional area of the spinal cord at the C4-5 level was expanded from 39.6 mm2 to 52.9 mm2 after surgery. The authors conclude that this operative procedure could be used as a new option for the treatment of cervical compressive myelopathy.
    No preview · Article · May 1999 · Journal of Neurosurgery
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    ABSTRACT: We used a commercially available computer-assisted navigation system (StealthStation; Sofamor Danek, Memphis, TN, USA) in both an in-vitro and a clinical study performed in 1996-1998. The basic data used for navigation were preoperative computed tomography (CT) scan imaging data. The position of the probe or drill guide was superimposed in real-time on a monitor. For the in-vitro study, ten plastic lumbar spine models (50 vertebrae) were used. The entrance hole for the screw was made by drilling, following navigation. Using the navigation system, we drilled 88 holes through the pedicles into the vertebral bodies of 44 vertebral models. All 88 pedicle holes were contained within the pedicle without perforation. The mean deviation of the hole positions from the surgical plan was 1.78 +/- 0.81 mm, and the mean angular deviation was 2.28 degrees +/- 1.92 degrees. In 29 patients, using the navigation system, we introduced 169 pedicle screws at the planned position. Fifty-one screws were used for thoracic and 118 screws for lumbar spinal fixation. All screws correctly passed through the pedicles. There were no neurological complications after surgery. Using this guided surgery system, we achieved satisfactory results both in the laboratory and in a clinical setting.
    No preview · Article · Feb 1999 · Journal of Orthopaedic Science