Takao Homma

Niigata University, Niahi-niigata, Niigata, Japan

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Publications (10)20.07 Total impact

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    ABSTRACT: A clinicobiomechanical study. To clarify the clinicobiomechanical characteristics of a segment with lumbar degenerative spondylolisthesis (LDS) using an original intraoperative measurement system. Although radiographical evaluation of LDS is extensively performed, the diagnosis of segmental instability remains controversial. The intraoperative measurement system used in this study is the first clinically available system that performs cyclic flexion-extension displacement of the segment with all ligamentous structures intact and can determine both the stiffness (N/mm) and neutral zone (NZ, [mm/N]). Forty-eight patients with LDS (males/females = 19/29, 68.5 yr; group D) were compared with 48 patients with lumbar spinal stenosis without LDS (males/females = 33/15, 64.8 yr, group N) in terms of symptoms, radiological, and biomechanical results. Instability was defined as a segment with NZ more than 2 mm. Symptoms (36-Item Short Form Health Survey), radiographical findings (radiographs, magnetic resonance images, computed tomographic scans), stiffness, NZ, and frequency of instability were also compared. Risk factors for instability were analyzed by multivariate logistic regression with a forward stepwise procedure. None of the physical function categories or radiological findings of 36-Item Short Form Health Survey and low back pain (visual analogue scale) differed significantly between the groups. Although NZ was significantly greater in group D (1.97) than in group N (1.73) (P < 0.05), the frequency of instability did not differ significantly between groups. Facet opening (odds ratio, 11.0; P < 0.01) and facet type (odds ratio, 6.0; P < 0.05) were significant risk factors for instability. Neither the symptoms nor the frequency of instability differed significantly between groups. The radiological findings of spondylolisthesis did not indicate instability, but facet opening and sagittally oriented facets were indicative of instability. The results of this study demonstrated that LDS is not always unstable in the measurement setting, suggesting that the instability of LDS can stabilize spontaneously during the natural course. N/A.
    Spine 12/2014; 39(26):2127-35. DOI:10.1097/BRS.0000000000000621 · 2.30 Impact Factor
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    ABSTRACT: OBJECTIVE: To compare the diagnostic efficacy of recumbent magnetic resonance imaging (MRI), computed tomography myelography (CTM), and myelography, with regard to indications for surgery for lumbar stenosis. BACKGROUND DATA: In patients with lumbar spinal stenosis-like disorders, small compressions are sometimes observed in magnetic resonance images acquired in the recumbent position, leading to potential misdiagnosis. Few prospective studies have compared the diagnostic accuracy of MRI, myelography, and CTM. Therefore, it is not clear whether myelography is necessary or not. METHODS: Fifty-four patients fulfilled the criteria. All patients underwent MRI, myelography, and CTM. MRI was performed with the patient in a normal recumbent position, and CTM was performed with the patients in both a recumbent and extended positions. All patients underwent surgery for lumbar spinal stenosis. Findings from visual examinations (sagittal images of MR, axial images of MR, axial reconstruction images of CTM and myelograms) were defined as compression + or -. We analyzed the sensitivity of the different examinations for diagnosis and the relationship among the types of images. RESULTS: Sensitivity was as follows: CTM 94.4 %, myelography 87.0 %, and MRI 75.9 %. In myelography, the images of 37 patients were worsened by dynamic synthesis (Dyn+). Among patients without compression on MRI, 11 showed compression on myelography. Of these 11, 8 of these patients were Dyn+, and 2 patients showed compression on myelography, but not on CTM and were Dyn+. Thus, some compression can be revealed only with myelography. CTM was more sensitive than axial MRI and showed compression in 12 patients that was not detected by axial MRI. CONCLUSION: Myelography revealed stenosis that was not detected by MRI. CTM with extension is more sensitive for detecting stenosis than MRI. Recumbent MRI cannot replace myelography or CTM in terms of dynamic findings and sensitivity.
    European Journal of Orthopaedic Surgery & Traumatology 03/2013; 23. DOI:10.1007/s00590-013-1209-y · 0.18 Impact Factor
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    ABSTRACT: Retrospective clinical study. To evaluate clinical results of patients with nontraumatic cervical lesions treated by cervical pedicle screw (PS) fixation and to discuss the surgical indications. PS fixation provides an outstanding stability for cervical lesions with instability. This technique, however, has a potential risk of vertebral artery, spinal cord, and nerve root injuries, which may be catastrophic. Fifty-eight patients were divided into 2 groups: patients with cervical kyphosis with vertebral destructive lesions (group D, n = 38) and those without destructive lesions (group ND, n = 20). Clinical results of the 2 groups were compared. The results of decompression and PS fixation for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) in this series were also compared with those of previous laminoplasty alone in patients with CSM and OPLL. Nape pain in group D improved in 86.7% of the patients. Overall neurologic status was improved in both groups. Bony fusion was confirmed in 100% of the cases that were alive in group D and 95% in group ND. Eight complications including 2 vertebral artery injuries occurred. The incidence of postoperative cervical complications in group ND was significantly higher than that in group D. Although PS fixation significantly corrected cervical kyphosis and maintained in both CSM and OPLL, operation time and intraoperative blood loss in cases treated by PS were significantly higher than those treated by laminoplasty alone. Improvement of nape pain and neurologic status did not differ with and without using PS fixation. There is an indication of cervical PS fixation for destructive lesions because of a high fusion rate with improvement of nape pain. On the other hand, there is no indication in cases of typical CSM and OPLL if a potential risk of vertebral artery or nerve injury is taken into account.
    Spine 11/2008; 33(21):2284-9. DOI:10.1097/BRS.0b013e31818043ce · 2.30 Impact Factor
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    ABSTRACT: In vivo quantitative measurement of lumbar segmental stability has not been established. The authors developed a new measurement system to determine intraoperative lumbar stability. The objective of this study was to clarify the biomechanical properties of degenerative lumbar segments by using the new method. Twenty-two patients with a degenerative symptomatic segment were studied and their measurements compared with those obtained in normal or asymptomatic degenerative segments (Normal group). The measurement system produces cyclic flexion-extension through spinous process holders by using a computer-controlled motion generator with all ligamentous structures intact. The following biomechanical parameters were determined: stiffness, absorption energy (AE), and neutral zone (NZ). Discs with degeneration were divided into 2 groups based on magnetic resonance imaging grading: degeneration without collapse (Collapse[-]) and degeneration with collapse (Collapse[+]). Biomechanical parameters were compared among the groups. Relationships among the biomechanical parameters and age, diagnosis, or radiographic parameters were analyzed. The mean stiffness value in the Normal group was significantly greater than that in Collapse(-) or Collapse(+) group. There was no significant difference in the average AE value among the Normal, Collapse(-), and Collapse(+) groups. The NZ in the Collapse(-) was significantly higher than in the Normal or Collapse(+) groups. Stiffness was negatively and NZ was positively correlated with age. Stiffness demonstrated a significant negative and NZ a significant positive relationship with disc height, however. There were no significant differences in stiffness between spines in the Collapse(-) and Collapse(+) groups. The values of a more sensitive parameter, NZ, were higher in Collapse(-) than in Collapse(+) groups, demonstrating that degenerative segments with preserved disc height have a latent instability compared to segments with collapsed discs.
    Journal of Neurosurgery Spine 04/2008; 8(3):255-62. DOI:10.3171/SPI/2008/8/3/255 · 2.38 Impact Factor
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    ABSTRACT: Retrospective analysis. To test the hypothesis that spinal cord lesions cause postoperative upper extremity palsy. Postoperative paresis, so-called C5 palsy, of the upper extremities is a common complication of cervical surgery. Although there are several hypotheses regarding the etiology of C5 palsy, convincing evidence with a sufficient study population, statistical analysis, and clear radiographic images illustrating the nerve root impediment has not been presented. We hypothesized that the palsy is caused by spinal cord damage following the surgical decompression performed for chronic compressive cervical disorders. The study population comprised 857 patients with chronic cervical cord compressive lesions who underwent decompression surgery. Anterior decompression and fusion was performed in 424 cases, laminoplasty in 345 cases, and laminectomy in 88 cases. Neurologic characteristics of patients with postoperative upper extremity palsy were investigated. Relationships between the palsy, and patient sex, age, diagnosis, procedure, area of decompression, and preoperative Japanese Orthopaedic Association score were evaluated with a risk factor analysis. Radiographic examinations were performed for all palsy cases. Postoperative upper extremity palsy occurred in 49 cases (5.7%). The common features of the palsy cases were solely chronic compressive spinal cord disorders and decompression surgery to the cord. There was no difference in the incidence of palsy among the procedures. Cervical segments beyond C5 were often disturbed with frequent multiple segment involvement. There was a tendency for spontaneous improvement of the palsy. Age, decompression area (anterior procedure), and diagnosis (ossification of the posterior longitudinal ligament) are the highest risk factors of the palsy. The results of the present study support our hypothesis that the etiology of the palsy is a transient disturbance of the spinal cord following a decompression procedure. It appears to be caused by reperfusion after decompression of a chronic compressive lesion of the cervical cord. We recommend that physicians inform patients and surgeons of the potential risk of a spinal cord deficit after cervical decompression surgery.
    Spine 04/2007; 32(6):E197-202. DOI:10.1097/01.brs.0000257576.84646.49 · 2.30 Impact Factor
  • Kazuhiro Hasegawa · Takao Homma · Haruka Shimoda
    ArgoSpine News & Journal 04/2007; 15(1):45-45. DOI:10.1007/BF03042874
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    ABSTRACT: Description of surgical technique and retrospective review of 13 cases. To describe the surgical technique of margin-free spondylectomy and the outcome of 13 cases and to discuss the advantages and limitations of the procedure. Recently, spondylectomy became a standard procedure by several pioneers. For extended malignant spine tumors involving pedicles or epidural space, however, performing an "en bloc" resection with a tumor-free margin remains a challenge. Our procedure consists of a combined anterior and posterior procedure with one or two stages. In the anterior procedure, tumor vertebrae are covered by the pleura or psoas muscles as a barrier. The posterior procedure includes decompression through the intact posterior elements, coverage of the tumor with all possible soft tissue barriers, and en bloc extirpation by rotating the tumor vertebrae around the spinal cord. We performed this procedure in 13 cases: 3 chondrosarcoma, 3 giant cell tumor, 1 osteosarcoma, 1 chordoma, and 5 metastases. Neurologic status and pain improved in all cases except asymptomatic cases. There was no local recurrence, except in 2 cases (chondrosarcoma with extirpation of 5 vertebrae, chordoma with multiple previous surgeries). Two cases of chondrosarcoma were disease-free 14 years and 13 years after surgery, respectively. Although the best chance for a cure in extended malignant tumors of the spine is realized through wide resection, the procedure is not yet standardized. Margin-free spondylectomy is technically demanding, but the procedure can be used with a confidence as a more radical surgery for tumors extending to the epidural space and the unilateral pedicle. A key to success is the surgical technique, including a 360 degree dissection around the tumor vertebrae, instrumentation, and removal of the lesion with all possible soft tissues maintained intact to function as a barrier, like the dura mater.
    Spine 02/2007; 32(1):142-8. DOI:10.1097/01.brs.0000251045.79708.7a · 2.30 Impact Factor
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    ABSTRACT: The mechanism underlying cervical flexion myelopathy (CFM) is unclear. The authors report the results of anterior decompression and fusion (ADF) in terms of neurological status and radiographically documented status in young patients and discuss the pathophysiological mechanism of the entity. Twelve patients underwent ADF in which autogenous iliac bone graft was placed. The fusion area was one segment in four cases, two segments in seven, and three segments in one. Neurological status, as determined by the Japanese Orthopaedic Association (JOA) score, radiographic findings, and intraoperative findings were evaluated. The mean follow-up period was 63.3 months (range 20-180 months). Grip strength was significantly improved and sensory disturbances resolved completely. Intrinsic muscle atrophy, however, persisted in all patients at the final follow-up examination. Local kyphosis in the flexed-neck position at the fusion levels was corrected by surgery. Preoperative computerized tomography myelography revealed that the cord compression index, which was calculated by anteroposterior and transverse diameters of the spinal cord, decreased to 33 +/- 6.2% in the flexed-neck position from 39.7 +/- 9.9% in the extended-neck position. The anterior dura mater-spinal cord distance decreased to 1.9 +/- 0.7 mm in the flexed-neck position from 4 +/- 1.2 mm in extended-neck position. The posterior dura mater-spinal cord distance increased to 2.5 +/- 1.1 mm in the flexed-neck position from 1.3 +/- 0.5 mm in the extended-neck position. Postoperative neurological status was improved in terms of grip strength, sensory disturbance, and JOA score, and local kyphosis in the flexed-neck position at the fusion levels was reduced and stabilized by ADF. In most cases local kyphosis in the flexed-neck position was demonstrated at the corresponding disc level, as were cervical cord compression and decrease of the anterior wall of the dura mater-spinal cord distance in the flexed-neck position. Therefore, the contact pressure between the spinal cord and anterior structures (intact vertebral bodies and intervertebral discs) in the mobile and kyphotic segments was considered to contribute to the onset of CFM. The ADF-related improvement of the clinical symptoms, preventing kyphotic alignment in flexion and decreasing movement of the cervical spine, supports the idea of a contact pressure mechanism. Furthermore, short ADF performed only at the corresponding segments can preserve more mobile segments compared with posterior fusion. Thus, ADF should be the first choice in the treatment of CFM.
    Journal of Neurosurgery Spine 09/2005; 3(2):86-91. DOI:10.3171/spi.2005.3.2.0086 · 2.38 Impact Factor
  • Kazuhiro Hasegawa · Takao Homma
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    ABSTRACT: Surgery for degenerative lumbar kyphoscoliosis (DLKS) is very challenging because the curve has become rigid due to circumferential osteoarthritic changes. Therefore, a standard procedure involving correction and fusion after decompression of the nerves has not yet been established. The authors have been searching for an effective procedure that provides adequate decompression and three-dimensional (3D) correction for symptomatic DLKS. In this report they describe a new 3D correction and fusion technique involving multilevel posterior lumbar interbody fusion. They analyze the results obtained in the first 23 cases and discuss the advantages and disadvantages of the procedure. The correction effect was excellent, and compared with other instrumentation-assisted procedures, this surgery is not remarkably invasive. Although the procedure is limited in achieving normal sagittal alignment and the acceleration rate of adjacent-disc degeneration remains relatively high, it is an option for the rigid deformity characterized by DLKS.
    Journal of Neurosurgery 08/2003; 99(1 Suppl):125-31. DOI:10.3171/spi.2003.99.1.0125 · 3.74 Impact Factor
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    ABSTRACT: The objective of this study was to compare efficacy of cervical surgery for myelopathy in patients > or = 70 and < or = 60 years of age. Forty patients > or = 70 years and 50 patients < or = 60 years of age with MRI and CT proven myelopathy were neurologically assessed using the JOA score. Three operative procedures were performed: anterior spinal fusion, laminoplasty, and laminectomy. Postoperatively, patients exhibited comparable outcomes irrespective of age or operative procedure performed. The only exception was the increase in postoperative neurologic complications noted for the older individuals with greater comorbidities.
    Journal of Spinal Disorders & Techniques 12/2002; 15(6):458-60. DOI:10.1097/00024720-200212000-00004 · 2.20 Impact Factor