Biomedical subjects

T Nishii

Publications and source records attributed to T Nishii.

At least 19 recordsLinked to original sources

PubMed2006

Disorders of acetabular labrum and articular cartilage in hip dysplasia: evaluation using isotropic high-resolutional CT arthrography with sequential radial reformation.

OBJECTIVE: Acetabular labral tear may predispose to adjacent articular cartilage disorder and hip osteoarthritis in patients with hip dysplasia. We evaluated the diagnostic ability of isotropic computed tomography (CT) arthrography with radial reformation technique for detection of acetabular labral and articular cartilage disorders, and evaluate those interactions in hip dysplasia. METHODS: Forty-one hips in 29 patients with hip dysplasia received CT arthrography with isotropic spatial resolution of 0.5mm. After processing of multiplanar radial reformation over the whole acetabular circumference, frequencies of labral tear and acetabular cartilage disorder were evaluated at six divided zones of the weight-bearing areas. Of the 41 hips, 20 hips underwent arthroscopic examinations, and sensitivity, specificity and accuracy for detecting labral tear and acetabular cartilage disorder by CT arthrography were calculated using the arthroscopic findings as the standard of reference. RESULTS: The sensitivity, specificity and accuracy of CT arthrography were 97%/87%/92% for labral tear and 88%/82%/85% for acetabular cartilage disorder, respectively, using arthroscopic findings as the reference. The CT arthrography showed significantly higher frequency of labral and acetabular cartilage disorders at the anterior zones. Those zones with labral tear had significantly higher frequency of adjacent cartilage disorder than zones without labral tear. CONCLUSIONS: Isotropic CT arthrography with radial reformation technique allowed simultaneous, accurate assessment of labral and cartilage disorders in the whole acetabular circumference. Our findings indicated that labral tear is closely associated with adjacent cartilage disorder in hip dysplasia.

Acetabulum↗

PubMed2006

[Completion pneumonectomy for pulmonary aspergillosis with hyper immunoglobulin-E syndrome].

A 22-year-old man was admitted to the department of pediatrics of our institute in February 2005, because of pulmonary aspergillosis. He had been diagnosed as hyper immunoglobulin-E syndrome in infancy, and repeated pulmonary infectious desease, such as pulmonary aspergillosis. He received art of right upper lobectomy by pulmonary aspergillosis at the age of 17. In February 2005, he had hemosputum and the chest X-ray showed a giant cavity with niveau in the right lung. In spite of medical treatment by antibiotics and antimycotics, the lesion rapidly increased in size. Therefore, right completion pneumonectomy and omentopexy around the bronchial stump was done. His postoperative course was uneventful.

Adult↗

PubMed2004

Segmental high intensity on T1-weighted hepatic MR images.

BACKGROUND: We investigated the diagnostic importance of segmental high-intensity (SHI) areas not corresponding to mass lesions on T1-weighted magnetic resonance (MR) images. METHODS: We conducted a retrospective investigation of hepatic MR images obtained from 634 patients during a 4-year period at our institution. Images were compared with findings reported in the patients' medical records. There were 16 patients (2.5%) with SHI areas not corresponding to a mass lesion. We compared MR images with plain computed tomographic (CT) scans (n = 16), angiograms (n = 12), and histologic findings (n = 10). RESULTS: The segments with intrahepatic bile duct dilatation showed hyperintensity on T1-weighted images. In six of 16 patients, the biliary duct was more dilated in the area of hyperintensity than in areas without hyperintensity. The SHI areas appeared as areas of low attenuation (n = 13), high attenuation (n = 1), or isoattenuation (n = 2) on plain CT scans. Histologically, these areas showed ductular proliferation and deposition of bile pigment within the hepatocytes. CONCLUSION: Segmental areas of increased signal intensity on T1-weighted images were probably due to intrahepatic cholestasis.

Adolescent↗

PubMed2004

Staple line coverage with absorbable mesh after thoracoscopic bullectomy for spontaneous pneumothorax.

BACKGROUND: Thoracoscopic simple bullectomy for primary spontaneous pneumothorax (PSP) has a relatively high postoperative recurrence rate and sometimes results in postoperative air leakage. One of the reasons for postoperative recurrence is the regrowth of bullae around the staple line. Therefore, reinforcement of the visceral pleura around the staple line is a reasonable way to prevent postoperative air leaks and recurrence. This study was done to determine the efficacy in preventing postoperative air leak and recurrent pneumothorax of widely covering the staple line with absorbable mesh after thoracoscopic bullectomy. METHODS: Wide coverage of the staple line with absorbable mesh was performed on 114 patients with PSP. These patients were retrospectively compared with 126 patients who underwent thoracoscopic simple bullectomy alone. RESULTS: The postoperative duration of chest drainage in the coverage group (mean, 1 day; range, 0-5) was significantly shorter than that in the simple bullectomy group (mean, 3 days; range 0-20). A prolonged air leak (>7 days) occurred in six patients in the simple bullectomy group, but there were no such leaks in the coverage group. Recurrent pneumothorax occurred in three patients (2.6%) in the coverage group and 12 patients (9.5%) in the simple bullectomy group. CONCLUSION: Wide coverage of the staple line with absorbable mesh is effective in preventing postoperative air leak and in decreasing the recurrence rates of PSP.

Adolescent↗

PubMed2004

Analysis of a retrieved UHMWPE acetabular cup crosslinked in air with 1000 kGy of gamma radiation.

The oxidation and degradation that accompany high dose gamma irradiation in air for crosslinking and sterilization are important because they could affect the clinical performance of polyethylene total joint implants. We report a clinical case of a 1000 kGy gamma-irradiated, highly crosslinked ultra-high molecular weight polyethylene acetabular cup retrieved 24 years postoperatively. Performance evaluations included absorbed radiation dose, total wear penetration, average wear rate, crystallinity, oxidation, and equibiaxial tensile properties. A retrieved acetabular cup of the same grade of polyethylene but gamma-sterilized using a conventional dose was used as control. The highly crosslinked and control cups took in about 1300 and 30 kGy of radiation, respectively, as measured using a trans-vinylene index. Direct dimensional measurements revealed average wear rates of the highly crosslinked and control cups were 0.04 and 0.06 mm/year, respectively. The oxidation index of the highly crosslinked cup was very high (0.679), but equivalent to that of a 1000 kGy irradiated reference cup. The retrieved highly crosslinked cup showed much higher equibiaxial ultimate tensile strength than the retrieved control cup. Based on these observations, the increased wear resistance and equibiaxial tensile properties that resulted from extensive crosslinking in the presence of air were partially offset by the adverse effects caused by immediate oxidation during the process.

Aged↗

PubMed2004

Preservation of the bone mineral density of the femur after surface replacement of the hip.

We investigated the effect of the Birmingham hip resurfacing (BHR) arthroplasty on the bone mineral density (BMD) of the femur. A comparative study was carried out on 26 hips in 25 patients. Group A consisted of 13 patients (13 hips) who had undergone resurfacing hip arthroplasty with the BHR system and group B of 12 patients (13 hips) who had had cementless total hip arthroplasty with a proximal circumferential plasma-spray titanium-coated anatomic Ti6A14V stem. Patients were matched for gender, state of disease and age at the time of surgery. The periprosthetic BMD of the femur was measured using dual-energy x-ray absorptiomentry of the Gruen zones at two years in patients in groups A and B. The median values of the BMD in zones 1 and 7 were 99% and 111%, respectively. The post-operative loss of the BMD in the proximal femur was significantly greater in group B than in group A. These findings show that the BHR system preserves the bone stock of the proximal femur after surgery.

Absorptiometry, Photon↗

PubMed2004

Full suspension mountain bike improves off-road cycling performance.

AIM: The purpose of the present study was to determine the effects of suspension systems on the cycling performance of cyclists during off-road bicycling. METHODS: Eight elite male cyclists (67.8+/-5.8 ml/min/kg of (.-)VO(2max)) performed 30-minute riding tests on bicycles with 2 different suspension setups: front suspension (FS) and front and rear suspension (FRS). Heart rate, blood lactate concentration, pedaling power, cadence, cycling velocity, and completed distance during the trial were measured creatin kinase (CK), lactic dehydrogenase (LDH) and glutamic-oxaloacetic transaminase (GOT) were measured before and after the trials. RESULTS: The average cadence during the trial was significantly higher (p<0.05) with the FRS (73.6+/-6.1 rpm) than the FS (70.2+/-6.2 rpm). Subjects rode significantly faster (p<0.05) on FRS (24.1+/-2.6 km/h) than FS bikes (22.9+/-2.4 km/h), although no significant difference was observed in pedaling power (240.7+/-26.6 W vs 242.2+/-28.8 W, FS vs FRS, respectively). Serum creatin kinase increased significantly (p<0.05) at 24 h after the trial when cyclists exercised with the FS bike. CONCLUSIONS: We conclude that the FRS improved cycling performance over rough terrain. FRS might therefore be more suitable for cross-country mountain bike races.

Adult↗

PubMed2003

[Intraoperative conversion and postoperative complication of video-assisted thoracoscopic surgery lobectomy for primary lung cancer].

By 2002, we had attempted video-assisted thoracoscopic surgery (VATS) lobectomy or segmentectomy for 140 primary lung cancer cases. Four cases (2.9%) were converted to standard posterolateral thoracotomy for oncologic reasons and aortic injury, and 7 cases (5%) were converted to minithoracotomy with a 10 cm incision due to almost injuring the vascular system. Average blood loss in these cases was 379 ml, and there was no blood transfusion required. Seven of these 11 cases had true pleural symphysis in the thoracic cavity. The remaining 129 cases, consisted of 93 lobectomies and 34 segmentectomies, performed with a minithoracotomy of 5 cm using 2 ports. Average surgical duration was 227 minutes, and blood loss was 100 ml. Postoperative complication occurred in 15 patients (11.6%). Major complications included 1 broncho-pleural fistula, 1 pulmonary infarction, 1 cerebral infarction and 1 respiratory failure needed for mechanical ventilation. However, there were no hospital deaths. The mean postoperative hospital stay was 12 days. We recommend that surgeons should pay attention to hilar dissection, particularly in the presences of adhesion and carefully judge whether to convert to thoracotomy at the time of hemorrhage. The VATS procedure has a low mortality and morbidity for lung cancer, but particulaly in high risk patients, requires care and management the same as an open thoracotomy.

Aged↗

PubMed2001

Additive effects of nicorandil on coronary blood flow during continuous administration of nitroglycerin.

OBJECTIVES: We examined whether patients with ischemic heart disease (IHD) should be treated with nicorandil, an adenosine triphosphate-sensitive potassium channel opener, in addition to the regular use of nitrates. BACKGROUND: It has been reported that nicorandil possibly has additive effects on nitroglycerin (NTG) treatment for angina, but the mechanism is not clear. METHODS: We directly measured anterograde coronary blood flow (CBF) with a Doppler guide wire to examine the effects of intravenous administration of NTG (0.3 mg) and nicorandil (6 mg) during continuous administration of NTG at a sufficient dose (25 microg/min) in subjects with normal and stenotic coronary arteries. RESULTS: Additional systemic administration of NTG decreased anterograde CBF (normal -19.7%; stenotic -21.2%). In contrast, nicorandil increased anterograde CBF in both normal (54.6%) and stenotic (89.6%) coronary arteries, without the coronary steal phenomenon. There was a tendency toward nicorandil-dilated diameters in the patients with stenotic arteries (p = 0.06). There were no effects of additional administration on pulmonary artery wedge pressure. There was no difference in changes in heart rate and mean aortic blood pressure between NTG and nicorandil therapy. CONCLUSIONS: These results suggest that in patients treated with nitrates, additional administration of nicorandil is more useful, in terms of increasing CBF, than additional administration of nitrates. Adjunctive use of nicorandil with nitrates may provide the further benefit of myocardial protection and may improve the prognosis of patients with IHD.

Aged↗

PubMed2001

Accuracy evaluation of surface-based registration methods in a computer navigation system for hip surgery performed through a posterolateral approach.

OBJECTIVE: Many computer navigation systems have recently been developed for brain surgery, and the use of such systems in orthopedic surgery is increasing. Intraoperative registration of preoperative images is one of the most important steps in controlling the overall accuracy of computer navigation systems. Various parameters, such as CT-scan slice thickness, reconstruction pitch, intraoperative data sampling area, and data sampling volume, may affect the accuracy of registration. The purpose of this study was to evaluate the effect of the aforementioned parameters on the accuracy of registration for hip surgery performed through a posterolateral approach, and to find a clinically suitable trade-off between accuracy and surgical invasiveness. MATERIALS AND METHODS: One cadaveric pelvis and one cadaveric femur were used for this study. Four alumina ceramic balls with a diameter of 28 mm and within 1 micrometer of sphericity were attached to the pelvis, and three similar balls attached to the femur, to determine relative position. CT-scan images of the pelvis and femur were obtained with a helical scanner. Three sets of slice thickness and slice pitch were chosen for data acquisition, and two additional sets of reconstructed data were made. Bone contours were extracted by cutting out the surrounding substrate at a given CT number threshold, and surface models of the bone were made from the resultant data. The positions of the pelvis and femur were tracked by LED markers attached to the bone using an optical three-dimensional position sensor (OPTOTRAK). Registration of the computer models to the real objects was performed by measuring the position of a certain number of surface points on each object with an OPTOTRAK pen-probe. RESULTS AND CONCLUSION: Slice thickness and reconstruction pitch affected the accuracy of registration. As the sampling area was expanded from the periarticular area to the distant peripheral area, accuracy increased slightly. Accuracy did not increase when the whole area was used, but in fact decreased, especially in the femur. The positive effect of increasing the number of sampling points was saturated at 30 points when the surface of the periarticular area was sampled. The following trade-off between accuracy and invasiveness, in terms of various parameters of preoperative and intraoperative data, is proposed as clinically optimal: perform the CT scan with 3-mm slice thickness and 1-mm reconstruction pitch, and sample the periarticular area with 30 sampling points. With these parameters, the accuracy of registration was 1.2 mm and 0.9 degrees of bias with 0.7 mm and 0.3 degrees of RMS in the pelvis, and 1.4 mm and 0.6 degrees of bias with 1.3 mm and 0.3 degrees of RMS in the femur.

Cadaver↗

PubMed2001

Comparison of fit and fill between anatomic stem and straight tapered stem using virtual implantation on the ORTHODOC workstation.

The objective of this article was to determine the influence of stem design on fit and fill using the preoperative planning workstation of the ROBODOC system. Anatomic ABG and straight Osteolock femoral components were virtually implanted into 50 femora (25 from patients with developmental dysplasia of the hip (DDH), 25 morphologically normal) on the workstation display. Fit and fill, and length of the proximal posterolateral femoral cortex removed by milling (LPFCR), were measured on the cross-sectional images. Lateral curvature (alpha angle) and anteversion of the femur were evaluated. The ABG components showed significantly better fit than the Osteolock components at the levels proximal to the lesser trochanter. The Osteolock components showed significantly greater LPFCR than the ABG components, especially in the patients with DDH. The patients with DDH showed significantly greater alpha angle and femoral anteversion than those with morphologically normal femora. With the Osteolock components, the alpha angle correlated significantly with femoral anteversion and LPFCR. Use of an anatomic proximal body of the stem helped to improve the proximal canal fit. Greater LPFCR was required when a straight stem was implanted in patients with a relatively high alpha angle.

Adult↗

PubMed2001

Full weight-bearing after cementless total hip arthroplasty.

In a prospective study of cementless total hip arthroplasty, 19 hips in 17 patients (Group A) were allowed full weight-bearing immediately after the operation while 18 hips in 16 patients (Group B) were first allowed weight-bearing after 6 weeks. Patients were matched for sex, age at surgery, height, weight, and follow-up period and there were no significant differences in hip scores between the two groups. Rehabilitation to gain walking ability with a cane lasted 5.8 days for Group A and 44.8 days for Group B (P = 0.0001). The hospital stay after surgery was 30.1 days for Group A and 46.7 days for Group B (P = 0.006). All patients showed bone ingrowth radiographically. There were no complications in either group.

Activities of Daily Living↗

PubMed2001

Influence of polyethylene and femoral head surface quality on wear: a retrieval study.

Thirty-two polyethylene sockets and 22 femoral heads were retrieved because of aseptic loosening more than 9 years after total hip arthroplasty. The volumetric wear rates of the retrieved polyethylene sockets were significantly greater in those coupled with an alumina head (P < 0.05). The retrieved alumina heads showed significantly better surface roughness and roundness than heads of Co-Cr and of stainless steel (P < 0.05). However, no significant difference was found in polyethylene quality demonstrated as fusion defects among the three different groups. The present study suggests that maintaining better surface roughness and roundness of the femoral heads does not always result in an in vivo reduction of polyethylene wear.

Adult↗

PubMed2001

Early MRI findings of rapidly destructive coxopathy.

To diagnose rapidly destructive coxopathy (RDC) in its early stages and understand the pathomechanism of associated joint destruction, ten cases of RDC were followed by periodic MRI from onset of the disease. In the initial stage (stage 1) of RDC, when radiographs revealed slight narrowing of the joint space, a small subchondral area of low signal intensity was observed on T(1)-weighted images (T1WI) and inhomogeneous high intensity was observed on T(2)-weighted images (T2WI) in the antero-lateral portion of the femoral head. When radiographs showed obliteration of the joint space (stage 2), MRI revealed a diffuse area of low intensity on TIWI and high intensity on T2WI in the proximal femur, including the femoral neck and head, suggesting extensive bone marrow edema. The femoral head and acetabulum were aggressively destroyed (stage 3) in all cases 3 to 6 months after the diffuse abnormal pattern was observed on MRI. MRI in stage 3 cases showed low intensity areas on both T1WI and T2WI. RDC did not show the band-like pattern of low intensity on T1WI and high intensity on T2WI that typify MRI findings in cases of osteonecrosis. When joint space narrowing is observed radiographically, the diffuse abnormal pattern of low intensity on T1WI and high intensity on T2WI induced by a subchondral small lesion might be an early sign of RDC.

Aged↗

PubMed2001

The feasibility of retrograde catheterization of the right gastric artery via the left gastric artery.

Retrograde catheterization of the right gastric artery was attempted in 22 patients for the purpose of proximal right gastric artery embolization. Retrograde catheterization was successfully performed in 12 of the 14 patients (86%) with smooth anastomoses. Retrograde catheterization was unsuccessful (n = 1) or time-consuming (n = 1) in two patients (14%) with smooth anastomoses. Right gastric artery embolization was successfully performed with microcoils in 13 of the patients. In all eight patients with tortuous anastomoses, catheterization was unsuccessful. Retrograde catheterization should be considered possible when preliminary angiography indicates a smooth anastomosis with the left gastric artery.

Adult↗

PubMed2001

Osteoblastic response to osteoarthrosis of the hip does not predict outcome of cementless cup fixation: 79 patients followed for 5-11 years.

We evaluated the influence of osteoblastic response to osteoarthrosis of the hip on the outcome of cementless acetabular cup after 91 total hip replacements in 79 patients. Of the 91 hips, 23 were atrophic, 37 normotrophic, and 31 hypertrophic, according to Bombelli's criteria. There were no clinical or radiographic differences among the three groups at the final follow-up (average 7 (5-11) years), when stable bone growth had been achieved by all of the acetabular cups in patients with the atrophic type, 35/37 of the normotrophic type, and all the hypertrophic type. Revision of the acetabular cup was performed on 1 hip of the normotrophic type, in connection with severe polyethylene liner wear and progressive osteolysis.

Adult↗

PubMed2001

Articular cartilage abnormalities in dysplastic hips without joint space narrowing.

Three-dimensional magnetic resonance imaging in the coronal and sagittal planes was performed in 25 normal hips of 16 volunteers and 70 dysplastic hips of 50 patients with clinical symptoms but without radiologic joint space narrowing. A high prevalence of cartilage abnormalities was detected, mostly located at the anterosuperior area in the hip: 31 hips (44%) in the acetabular cartilage and five hips (7%) in the femoral cartilage showed a mild to moderate defect of cartilage thickness. The presence of cartilage abnormalities had a statistically significant correlation with age of the patients and severity of hip pain. Of 31 hips with cartilage abnormalities, sagittal magnetic resonance images showed abnormalities in 30 (97%), whereas coronal magnetic resonance images revealed abnormalities only in 11 (35%). A high incidence of cartilage abnormalities in the preradiologic stage suggests the need for more sensitive modalities for early diagnosis. Magnetic resonance imaging in the sagittal plane allows detailed assessment of early cartilage abnormalities.

Adolescent↗

PubMed2001

Analysis of survivorship after total hip arthroplasty using a ceramic head.

To determine the clinical efficacy of an alumina ceramic head, 119 cemented total hip arthroplasties in 97 patients using an alumina head coupled with ethylene oxide gas sterilized polyethylene were reviewed. Eighty-two patients (101 hips) with greater than 10 years followup were evaluated clinically and radiographically (range, 10-17.6 years), and 97 patients (119 hips) were evaluated for survivorship analysis (range, 0.6-17.6 years). The average functional hip scores according to Merle d'Aubigné and Postel improved from 8.6 preoperatively to 15.0 at the final followup, and 57 patients (64 hips) had no pain. The average polyethylene wear rate was 0.15 mm/year (range, 0.04-0.34 mm/year). Patients with polyethylene wear greater than 3 mm showed significantly higher rates of acetabular loosening. Fifteen-year survival rates (with 95% confidence intervals) with radiographic evidence of aseptic loosening as the end point were 46.8% +/- 13.4% in acetabular components and 91.9% +/- 6.6% in femoral components. Fifteen-year survival rates of hip arthroplasties with revision because of aseptic loosening as the end point were 75.3% +/- 10.2% and 97.9% +/- 3.0%, respectively. Results of the current study suggest that using an alumina head instead of a metal head may not be beneficial when coupled with ethylene oxide gas sterilized polyethylene.

Adult↗