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ABSTRACT: PURPOSE: Unilateral hypertrophy of the lateral mass of the atlas is an extremely rare condition. The authors present a rare type of unilateral atlantal mass hypertrophy with atlanto-occipital fusion which is associated with an invaginated lateral mass of the atlas and the odontoid process into the foramen magnum. METHODS: A 45-year-old woman presented with a 2-year history of progressive bilateral weakness in the upper and lower extremities and gait disturbance. The left lateral mass of the atlas was hypertrophied and had invaginated into the foramen magnum with the odontoid. The spinal cord was severely compressed at the level of the foramen magnum, surrounded by the lateral mass of the atlas, the odontoid process and the occipital bone. RESULTS: First, ventral decompression was performed using a transmandibular approach. The anterior arch of the atlas, the medial side of the hypertrophied lateral mass and the odontoid process were resected. Two weeks after primary surgery, posterior occipitocervical fusion was performed. The postoperative course of the patient was uneventful. Three years after the operation, she could walk without assistance and her paresthesia improved. CONCLUSIONS: To our knowledge, such a case of unilateral atlantal mass hypertrophy associated with atlanto-occipital fusion has not been described previously. The authors discuss the pathology of this case and review the literature on unilateral atlantal mass hypertrophy and associated anomalies of the upper cervical spine.
European Spine Journal 11/2012; · 1.97 Impact Factor
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ABSTRACT: Retrospective review.
To identify risk factors for traumatic cervical spinal cord injury (SCI) associated with ossification of the posterior longitudinal ligament (OPLL) by comparing patients with SCI and those with cervical myelopathy (CM) associated with OPLL.
Although the prevalence of OPLL among patients with cervical SCI is high, little is published about the risk factors for SCI associated with OPLL.
We evaluated 3 groups of patients: 34 with SCI associated with OPLL, 32 with CM associated with OPLL, and 32 normal controls. Developmental canal diameter, spinal canal stenosis, type of OPLL, and presence of ossification of the anterior longitudinal ligament (OALL) were evaluated using 3-dimensional computed tomography.
The mean age of the SCI group was 71.5 years, significantly more than that of the CM group (63.3 years). The SCI and CM groups had significantly smaller developmental canals than controls. Canal stenosis caused by OPLL was significantly more severe in the CM group than in the SCI group. There were no significant differences in sex distribution or the type of OPLL. Mixed or segmental types of OPLL were the main cause of SCI and CM. The SCI group showed a significantly higher incidence of OALL (56%) than the CM group (22%). Cervical SCI occurred at the edge of the OPLL or OALL in 20 patients (59%). If limited to mixed or continuous types of OPLL, 18 of the 19 patients (95%) sustained SCI at the edge of the OPLL or OALL.
Risk factors for cervical SCI associated with OPLL were being elderly, having a mixed or segmental type of OPLL, and presence of OALL. Most instances of SCI occurred at edges of the OPLL or OALL. Severe spinal canal stenosis caused by OPLL was not an essential risk factor for developing SCI.
Spine 08/2011; 37(8):660-6. · 2.08 Impact Factor
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ABSTRACT: Although the prognosis of Perthes' disease at skeletal maturity is considered favorable, little is known about the long-term results after middle age.
We retrospectively analyzed the radiographic and functional outcomes of 67 patients (70 hips) who had been treated for Perthes' disease. Of these patients, 28 patients (29 hips) were evaluated using JOA (Japanese Orthopaedic Association) score and radiographs at follow-up (Group 1), 39 patients (41 hips) were evaluated by a postal questionnaire (Group 2). The mean follow-up period was 36.1 years. The mean age at follow-up was 43.1 years.
Group 1, good radiographic results (Stulberg class I or II) were achieved in 59% of hips. No osteoarthritis (Tönnis Grade 0) was observed in only 48% of hips. The clinical results were good (JOA score ≥ 70) in 79% of hips. Disturbance of walking ability and activities of daily living was little. The Tönnis grade and JOA score declined after 40 years of age. All patients older than 50 years showed severe osteoarthritis. The severity of osteoarthritis correlated significantly with age at follow-up. Group 2, the clinical results were good (JOA score ≥ 56) in 76% of hips. In both groups, no patient had undergone total hip arthroplasty. Younger age at diagnosis (<8 years) correlated significantly with a better result. The JOA score correlated significantly with age at follow-up.
Patients who were treated for Perthes' disease have a risk of osteoarthritis and a clinically poor outcome after the age of 40-50 years.
Archives of Orthopaedic and Trauma Surgery 01/2011; 131(5):701-7. · 1.37 Impact Factor
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ABSTRACT: Case report and clinical discussion.
We report a rare case of delayed onset of cerebral infarction caused by an embolism after cervical pedicle screw (CPS) fixation.
CPS has a risk of vertebral artery (VA) injury. CPSs sometimes breach the transverse foramen without rupture of the VA. Most breaches are not considered harmful.
We present a case in a 71-year-old man who underwent an operation for CPS fixation and laminoplasty for cervical spondylomyelopathy. He presented symptoms of hemiparesis 3 days after the operation. The left C4 pedicle screw was proven to breach the transverse foramen. An angiogram showed a thrombus cranial to the screw.
The patient underwent anticoagulation therapy without removal of screw. After 2 weeks, the thrombus had disappeared. Subsequently, the pedicle screws were removed. At final follow-up, the patient complained of a grade 4/5 hemiparesis, facial nerve palsy, and hearing loss in his left ear.
To our knowledge, this is the first case report of delayed onset of cerebral infarction caused by an embolism after CPS fixation. When a CPS perforates the transverse foramen, even if no apparent VA injury occurs during the operation, the surgeon must take care not to risk cerebral infarction because of an embolism.
Spine 01/2010; 35(2):E63-6. · 2.08 Impact Factor
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ABSTRACT: Systemic administration of prostaglandin E2 receptor (EP4) selective agonist increases both bone formation and resorption, and consequently leads to an increase in bone mass. Although previous studies have reported that EP4 agonist enhanced bone remodeling and fracture healing, it was not known if EP4 agonist activates the bone-biomaterial interface. Bioactive titanium prepared by chemical and thermal treatment can bond to living bone and is suitable for use in clinical applications in cementless fixation devices. Therefore, we examined whether the administration of EP4 agonist enhances the bonding strength between bone and bioactive titanium. Bioactive titanium plates were inserted into the tibia bone of rabbits and examined histologically and biomechanically at 4, 8, and 16 weeks. EP4 agonist was administrated systemically every 2 weeks after surgery. A non-administrated control group, a low-dose group (10 microg/kg body weight (BW)), and a high-dose group (100 microg/kg BW) were compared. The bonding strength of bioactive titanium in the EP4 agonist groups was significantly higher than that in the control group at both 4 and 8 weeks, and enhanced bone remodeling and direct bonding around the bioactive titanium plates was observed only in the EP4 agonist groups at 4 weeks. EP4 agonist enhanced bone formation around the bioactive titanium plate, and achieved early direct bone bonding.
Biomaterials 04/2008; 29(7):877-83. · 7.40 Impact Factor
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ABSTRACT: To determine whether sensitivity to polyethylene particles varies among patients, we studied 25 patients who had undergone total hip arthroplasty. We used pelvic radiographs to measure annual polyethylene wear and the area of osteolysis. The ratio of the area of osteolysis to the volumetric polyethylene wear was defined as sensitivity index. Adherent cells from peripheral blood were cocultured with polyethylene particles, and the amount of bone-resorptive cytokines was measured. The amount of interleukin-6, but not of interleukin-1beta or tumor necrosis factor-alpha, released from adherent cells in the in vitro experiment correlated with the in vivo sensitivity indices. This technique appears capable of predicting the development of polyethylene-induced osteolysis, allowing surgeons to avoid using polyethylene as the bearing surface in patients at risk for osteolysis.
The Journal of Arthroplasty 11/2007; 22(7):966-73. · 2.38 Impact Factor
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ABSTRACT: The wear rate of polyethylene against alumina was demonstrated to be lower than against metal, and the results of early clinical studies of alumina-on-polyethylene combination were as good as expected, but the long-term results of alumina ceramic heads were not as good, as reported by several authors. The purpose of this study was to assess the clinical results over 10 years of cemented total hip arthroplasty (THA) with two types of alumina head: old and current alumina.
We compared the clinical results of these two types of alumina used for cemented THA. The first type was old alumina (containing 7% yttria), and 77 hips with a 28-mm head (group I) were included. The second type was current alumina (highly purified alumina), and 50 hips with a 26-mm head (group II) and 88 hips with a 22-mm head (group III) were included. The mean follow-up was 17 years 4 months in group I, 12 years 3 months in group II, and 10 years in group III.
The Kaplan-Meier survival analysis, with revision for any reason as the endpoint, predicted 10-year survival rates of 90.8%, 100%, and 97.5% for groups I, II, and III, respectively. The survival curves differed significantly only between groups I and II. The probabilities of 10-year survival of the pros-theses with radiological loosening as the endpoint were 77.2%, 91.6%, and 96.5%, respectively. The survival curves showed significant differences only between groups II and III.
The old alumina showed a higher wear rate and rougher surface on the femoral head than did the current alumina in our previous study. The clinical results also indicated superiority of current alumina over old alumina. The difference in the size of the femoral head (26 vs. 22 mm) did not affect the clinical results.
Journal of Orthopaedic Science 08/2005; 10(4):378-84. · 0.84 Impact Factor
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Eijiro Onishi
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ABSTRACT: Kyoto University (京都大学) 0048 新制・論文博士 博士(医学) 乙第12443号 論医博第2002号 新制/医/982 28053 2010-03-23 (主査)教授 成宮 周, 教授 戸口田 淳也, 教授 開 祐司 学位規則第4条第2項該当
