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Biomedical subjects

K Ido

Publications and source records attributed to K Ido.

At least 55 records · Page 3Linked to original sources
PubMed2000

Reduction of blood loss using tranexamic acid in total knee and hip arthroplasties.

There have been several attempts to reduce postoperative blood loss in patients undergoing total arthroplasty. Benoni et al. reported the usefulness of tranexamic acid in total knee arthroplasty (TKA). We investigated its effect in TKA and total hip arthroplasty (THA). Blood loss was significantly reduced in patients given tranexamic acid in both the TKA and THA groups, and no severe complications, such as venous or pulmonary thrombosis, were noted in any of the patients who received the agent. Administration of tranexamic acid seems to be useful for reducing postoperative blood loss in TKA and THA.

Antifibrinolytic Agents↗
PubMed2000

Limitations of three-dimensional intraductal ultrasonography in the assessment of longitudinal spread of extrahepatic bile duct carcinoma.

We investigated the utility and limitations of three-dimensional intraductal ultrasonography (3D-IDUS), for the assessment of the extent of longitudinal cancer spread to the hepatic side by extrahepatic bile duct carcinoma. In eight patients with extrahepatic bile duct carcinoma. 3D-IDUS was used to assess longitudinal cancer extension to the hepatic side prior to resection. When the linear dimension of 3D-IDUS showed bile duct wall thickening that was connected to the tumor and which became thin at a point, it was determined to be the front formation of longitudinal cancer extension. The findings were examined in relation to histologic information from the resected specimen. Although 3D-IDUS showed front formation of wall thickening in two patients, it accurately reflected the histological margin of the longitudinal cancer extension in only one patient. In the other patient, the wall thickening was longer than the histological margin. When 3D-IDUS showed bile duct wall thickening without front formation (n = 2), the wall thickening was longer than the histological margin of the longitudinal cancer extension. Even when 3D-IDUS did not show wall thickening (n = 4), one of these patients showed cancer spread histologically. As a result, the accuracy in assessing longitudinal cancer extension by 3D-IDUS was only 50%. Even if the linear dimension of 3D-IDUS demonstrated front formation of thickening of the bile duct, it reflected not only cancer extension but also inflammatory wall thickening.

Aged↗
PubMed2000

Percutaneous recanalization of the bile duct along an endoscopic naso-biliary catheter.

Percutaneous recanalization of the bile duct is essential for placing biliary stents and carrying out other interventions. This prospective study was performed to establish safe approaches for percutaneous recanalization of the bile duct when it had previously resulted in failure. Between July 1995 and July 1999, percutaneous recanalization of the bile duct was attempted in 58 patients with a malignant biliary stenosis. When recanalization failed, an endoscopic naso-biliary drainage (ENBD) catheter was placed across the stenosis. The procedure was again attempted along the ENBD catheter. In the period of the study, four patients underwent successful recanalization after ENBD, although attempts prior to ENBD had been unsuccessful. As a result, the success rate of recanalization in the period was 100% (58/58). When recanalization fails, the use of an ENBD catheter may provide access to the biliary tree, and the biliary stenosis can be recanalized safely.

Abdominal Neoplasms↗
PubMed2000

Placement of endoscopic naso-biliary drainage does not preclude subsequent percutaneous transhepatic biliary drainage.

We prospectively investigated whether the placement of endoscopic naso-biliary drainage (ENBD) precluded percutaneous transhepatic biliary drainage (PTBD). In 40 patients, the caliber of the intrahepatic bile duct was measured prior to ENBD by ultrasonography. When PTBD was required after ENBD, the ENBD catheter was clamped for 1 to 2 h before PTBD, and its caliber was again measured at the time of PTBD. When PTBD was performed within 7 days (mean, 1.8 days) after ENBD (n = 27), the size of the intrahepatic bile duct was 5.0 +/- 2.3 mm before and 4.6 +/- 2.3 mm after ENBD. There was no significant difference between these values (P > 0.5). When PTBD was performed 8 to 40 days (mean, 17.8 days) after ENBD (n = 13), the bile duct diameter was significantly reduced, from 4.2 +/- 1.5 mm (pre-ENBD) to 1.8 +/- 1.7 mm (post-ENBD) (P < 0.05). When PTBD was conducted within 7 days (mean, 1.8 days) after ENBD, previous ENBD did not induce collapse of the bile duct, if the ENBD catheter was clamped for 1 to 2 h before the puncture of the bile duct.

Bile Ducts, Intrahepatic↗
PubMed2000

Intraductal US in assessing the effects of radiation therapy and prediction of patency of metallic stents in extrahepatic bile duct carcinoma.

BACKGROUND: We assessed the local effects of radiation therapy using intraductal ultrasonography (US) to predict the subsequent patency of metallic stents in bile duct carcinoma. METHODS: Data from 16 patients with extrahepatic-suprapancreatic bile duct carcinoma were prospectively analyzed. Thin-caliber US probes (2.0 mm diameter/20 MHz frequency and 2.8 mm diameter/10 MHz frequency) were inserted into the bile duct via a percutaneous transhepatic approach pre- and postradiation therapy to evaluate the effects of treatment. When intraductal US showed a reduction in bile duct wall thickness of 30% or greater or showed a lessening of vessel (portal vein or right hepatic artery) invasion, radiation therapy was judged to be effective. Noncovered metallic stents were then inserted, and their patency was evaluated over time. RESULTS: When radiation therapy was effective (n = 7), the metallic stent was patent for 522 +/- 571 days. When radiation was ineffective (n = 9), the metallic stent was patent for only 188 +/- 159 days. When radiation therapy was ineffective, stent obstruction occurred in 6 of 9 (66.7%) patients during this period, significantly more frequently than when radiation therapy was effective (14.3%, p < 0.05). CONCLUSIONS: Assessment of local radiation effects by intraductal US is useful for predicting patency of metallic stents in bile duct cancer.

Aged↗
PubMed2000

Summation between nearby motion signals and facilitative/inhibitory interactions between distant motion signals.

To explain the finding that motion assimilation was dominant between nearby motion signals while motion contrast between distant ones, a center-surround antagonistic mechanism was proposed [Nawrot & Sekuler (1990). Vision Research, 30, 1439-1451]. However, motion assimilation occurred not only between nearby signals but also between distant ones, suggesting the existence of a center-surround non-antagonistic mechanism [Ido. Ohtani & Ejima (1997). Vision Research, 37, 1565-1574]. The present study was designed to provide direct evidence for the non-antagonistic mechanism, and to examine further the motion interactions which operate in different spatial scales. The nature of motion interaction between the test and the inducer was examined by varying the size, the number of frames, the frame duration and the inter-frame displacement of random-dot kinematograms. The results were consistent with the notion that there are three types of interactions in human motion processing; one is a summation process effective within nearby regions, and the other two are facilitative and inhibitory induction processes operating over larger spatial scales. Analysis of the results in terms of the Fourier components suggests that the facilitative and the inhibitory induction processes may be sensitive, respectively to the lower and the higher temporal frequency components of the stimulus.

Humans↗
PubMed2000

Radiographic evaluation of bioactive glass-ceramic grafts in postero-lateral lumbar fusion.

STUDY DESIGN: Follow-up study of bioactive glass-ceramic graft for postero-lateral fusion (PLF) in the lumbar spine was performed using plain radiography. OBJECTIVES: To investigate the fusion state of the porous stick type of bioactive glass-ceramic which has been used in PLF in the lumbar spine, by plain radiography, and to evaluate the usefulness of this technique. METHODS: Fourteen patients who underwent PLF using apatite and wollastonite-containing glass-ceramic (A-W. GC) were followed-up for more than 1 year and 6 months by plain radiography. RESULTS: Six patients who were followed up for more than 2 years were considered to have obtained subtotal or total fusion. CONCLUSION: PLF using A-W. GC mixed with autologous grafted bone can preserve bone stock without the need to harvest a bone graft from the iliac crest and will be useful for PLF in the lumbar spine.

Bone Transplantation↗
PubMed2000

Double-catheter method to prevent dislodgement during percutaneous transhepatic cholangioscopy.

BACKGROUND: We evaluated the utility of the double-catheter method to establish the track for percutaneous transhepatic cholangioscopy (PTCS). METHODS: Dilatation of the percutaneous transhepatic track to 16F for PTCS was attempted in 105 patients. The results were prospectively analyzed. Using the single-catheter method (n = 22), a 16F PTCS catheter was replaced without the inner catheter. Using the double-catheter method (n = 83), a 7F catheter with a balloon tip was inserted through a 16F PTCS catheter. The balloon was located distal to the major duodenal papilla. The double-catheter method was further subclassified as follows: Method 2A (n = 62), the tip of the outer catheter (16F) was not advanced through biliary stenoses; Method 2B (n = 21), the catheter was advanced through biliary stenoses. RESULTS: In the patients treated by the double-catheter method, dislodgement of the catheter did not occur, whereas the single-catheter became dislodged in 18% (p < 0.0005). The morbidity of method 2A (0%) was less than that of method 2B (14%) (p < 0.005). CONCLUSION: The double-catheter method prevents dislodgement of the PTCS catheter. The outer catheter should not be advanced to the biliary stenosis.

Adult↗
PubMed2000

Access for percutaneous transhepatic cholangioscopy in patients with nondilated bile ducts using nasobiliary catheter cholangiography and oblique fluoroscopy.

BACKGROUND: Percutaneous transhepatic biliary drainage is required for percutaneous transhepatic cholangioscopy. However, puncture of nondilated bile ducts under ultrasonographic guidance is difficult. METHODS: In 10 patients with no ultrasonographic evidence of intrahepatic bile duct dilatation, percutaneous transhepatic biliary drainage was performed under fluoroscopic guidance using cholangiography obtained via a nasobiliary drainage catheter. Direct puncture was performed by means of a left ventral approach using oblique C-arm fluoroscopy. RESULTS: Bile duct puncture was successful in all patients. There were no procedure-related complications. Subsequent cholangioscopy was successful in all patients. CONCLUSIONS: Direct puncture using nasobiliary drainage cholangiography and oblique fluoroscopy is a useful method when cholangioscopy is necessary in patients with nondilated bile ducts.

Adult↗
PubMed2000

Porous apatite-wollastonite glass-ceramic as an intramedullary plug.

We evaluated the efficacy and biocompatibility of porous apatite-wollastonite glass ceramic (AW-GC) as an intramedullary plug in total hip replacement (THR) for up to two years in 22 adult beagle dogs. Cylindrical porous AW-GC rods (70% porosity, mean pore size 200 microm) were prepared. Four dogs were killed at 1, 3, 6 and 12 months each and six at 24 months after implantation. Radiological evaluation confirmed the efficacy of porous AW-CG as an intramedullary plug. Histological evaluation showed osteoconduction at one month and resorption of the porous AW-GC, which was replaced by newly-formed bone, at 24 months. Our findings indicate that porous AW-GC can be used clinically as an intramedullary plug in THR.

Animals↗
PubMed2000

A new-type titanium intervertebral spacer and its insertion device used in posterior lumbar interbody fusion.

We have recently developed a new-type trapezoid mesh cage (TPM cage) together with an insertion device, which for use as a new titanium mesh intervertebral spacer in posterior lumbar interbody fusion (PLIF). The TPM cage has sufficient mechanical strength, a large contact area that gives good long-term stability, and preserves the initial disc height to provide good balance. The insertion device for the TPM cage is useful not only for handling the implant but also for controlling the implant insertion direction. The TPM cage and its insertion device are promising for use in PLIF.

Biocompatible Materials↗
PubMed1999

Bone-bonding ability of bioactive bone cement under mechanical stress.

Bioactive bone cement (BABC) is able to bond to bone through a Ca-P rich layer. It was evaluated so far in a rat tibial model, where no mechanical stresses are supposed to take place. The objective is to investigate the behavior of BABC in the environment of posterolateral spinal fixation model, in which the bone cement interface is exposed to continuous mechanical stress. Japanese white rabbits were used. Fixation of L5-L6 segment was done by wiring the spinous and transverse processes of L5 and L6 vertebrae. Then BABC was applied over the transverse processes and the intertransverse process membrane on both sides. Polymethylmethacrylate (PMMA) bone cement was used similarly in the control group. Animals were sacrificed after 1 day, 4, 8, and 16 weeks postoperatively. Bone cement interface was examined using Giemsa surface staining and SEM, and affinity index was measured. Biomechanical testing was done nondestructively in right and left torsion. BABC bonded to bone directly with no intervening soft tissue at 4, 8, and 16 weeks, while soft tissue was consistently seen between PMMA bone cement and bone. BABC-spine constructs were stiffer than PMMA-spine constructs at all time intervals. BABC bonded directly to bone under mechanical stress and afforded stiffer fixation than PMMA bone cement.

Animals↗
PubMed1999

Laparoscopic cholecystectomy in gallstone patients with acute cholecystitis.

It remains controversial whether patients with gallstones with acute cholecystitis should be operated on early, or whether surgery should be delayed until the acute phase subsides. To help resolve this question, we retrospectively studied 109 patients with acute cholecystitis, 56 of whom underwent laparoscopic cholecystectomy after acute cholecystitis had subsided (delayed group) and 53 of whom underwent early laparoscopic cholecystectomy--within 7 days after admission (early group). On admission, the inflammatory findings in the two groups were very similar; however, at operation, the inflammatory findings were alleviated in the delayed group, while they remained unchanged in the early group. The mean operative time for the two groups was very similar. As for intraoperative complications, there was no conversion to laparotomy in either group, and there were no major complications in either group. The total hospital stay was 37.7 +/- 14.4 days for the delayed group and 12.7 +/- 2.0 days for the early group, showing a highly significant difference (P < 0.001). Early laparoscopic cholecystectomy seems to be better than delayed treatment for patients with gallstones with acute cholecystitis.

Acute Disease↗
PubMed1999

Assessment of residual bile duct stones with use of intraductal US during endoscopic balloon sphincteroplasty: comparison with balloon cholangiography.

BACKGROUND: We sought to determine the utility of intraductal ultrasonography (IDUS) in detecting residual bile duct stones during endoscopic balloon sphincteroplasty. METHODS: Eighty-one consecutive patients with bile duct stones who underwent IDUS during endoscopic balloon sphincteroplasty were studied. IDUS was performed with a thin-caliber ultrasonic probe (diameter 2.0 mm, frequency 20 MHz) by a transpapillary route after stone extraction. When IDUS or balloon-retrograde cholangiography suggested residual stones, the bile duct was cleared again with a Dormia basket. Extraction of the stones was confirmed by direct duodenoscopic visualization. Videotapes of IDUS and cholangiograms were reviewed retrospectively without knowledge of the results of other diagnostic modalities. RESULTS: In 27 of 81 patients (33%), IDUS detected small residual stones not seen on cholangiography. When stones were fragmented with mechanical lithotripsy, the accuracy of IDUS in detecting small residual stones was significantly greater than that of balloon-endoscopic retrograde cholangiography (95% vs 50%, p < 0. 001). When the bile duct was greater than 10 mm in diameter, the accuracy of IDUS in detecting small residual stones was significantly greater than that of cholangiography (92% vs. 56%, p < 0.001). CONCLUSIONS: IDUS is useful for detecting small residual bile duct stones during endoscopic balloon sphincteroplasty when stones are fragmented by mechanical lithotripsy or when there is evidence of a dilated bile duct (>10 mm).

Adult↗
PubMed1999

Preoperative assessment of congenital bile duct dilatation using intraductal US.

BACKGROUND: Although congenital bile duct dilatation is frequently associated with biliary tract cancer, conventional cholangiography often does not demonstrate small ductal tumors. This is the first prospective study of the value of intraductal ultrasonography (US) in the examination of the extrahepatic bile ducts in patients with congenital bile duct dilatation. METHODS: Intraductal US via a transpapillary route was used in consecutive patients with congenital bile duct dilatation. A 2.0 mm diameter, 20 MHz frequency catheter probe was used. The images were correlated with the results of histologic examination of the resection specimens. RESULTS: Intraductal US was performed successfully via the transpapillary route in 8 of 10 patients. In the other 2 patients, the percutaneous transhepatic route was used. In the 6 patients with cylindrical dilatation, intraductal US demonstrated the entire extrahepatic bile duct. In 1 patient, it showed a bile duct cancer not demonstrated by cholangiography. In 2 of the 4 patients with cystic dilatation, intraductal US did not demonstrate the entire extrahepatic bile duct because of the low penetration depth of the probe. Percutaneous transhepatic cholangioscopy was required in these patients. CONCLUSIONS: Intraductal US is useful for demonstrating cancers in the extrahepatic bile ducts in patients with congenital cylindrical ductal dilatation.

Adult↗
PubMed1999

The role of laparoscopic US and laparoscopic US-guided aspiration biopsy in the diagnosis of multicentric hepatocellular carcinoma.

BACKGROUND: Detection of small hepatocellular carcinomas has become possible with improvements in various diagnostic imaging techniques. However, intraoperative US can detect lesions not visualized by any preoperative imaging study in which case it is difficult to determine whether the lesion is a hepatocellular carcinoma. METHODS: Nodular lesions detected by laparoscopic US in 186 patients with hepatocellular carcinoma were examined and we evaluated the diagnostic ability of laparoscopic US to detect multicentric hepatocellular carcinoma. RESULTS: One hundred thirty-four new nodular lesions were detected by laparoscopic US in 64 (34.4%) of 186 patients. Aspiration biopsy under laparoscopic US guidance was performed on the 134 nodules, and 28 nodules in 23 (12.4%) of the 186 patients were histologically diagnosed as hepatocellular carcinoma. Of these 23 patients, 18 had been diagnosed with solitary hepatocellular carcinoma before laparoscopic US. One hundred six of the newly detected lesions were initially diagnosed as noncarcinomatous nodules, but the diagnosis of 10 of these lesions was changed to hepatocellular carcinoma during follow-up that was as long as 96 months. CONCLUSIONS: Laparoscopic US is useful in the initial diagnosis of hepatocellular carcinoma and impacts treatment selection by more accurately defining the presence of multicentric hepatocellular carcinomas.

Biopsy, Needle↗
PubMed1999

Preoperative assessment of extrahepatic bile duct carcinoma using three-dimensional intraductal US.

BACKGROUND: We investigated the utility of a new imaging modality, three-dimensional intraductal ultrasonography (US), for staging bile duct cancer. METHODS: In eight patients with extrahepatic bile duct carcinoma, two- and three-dimensional intraductal US was used to assess tumor invasion of the right hepatic artery, portal vein, and pancreatic parenchyma before resection. The findings were correlated with histologic information from the resected specimen. RESULTS: Three-dimensional intraductal US enabled accurate assessment of tumor invasion of the right hepatic artery in 88% of cases, the portal vein in 100%, and pancreatic parenchyma in 100%. Two-dimensional intraductal US enabled accurate assessment of invasion of these structures in 88%, 88%, and 88% of cases. CONCLUSIONS: Three-dimensional intraductal US is useful in assessing tumor stage in bile duct carcinoma.

Aged↗