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J Machi

Publications and source records attributed to J Machi.

At least 19 recordsLinked to original sources
PubMed2006

Routine laparoscopic ultrasound can significantly reduce the need for selective intraoperative cholangiography during cholecystectomy.

BACKGROUND: The use of intraoperative cholangiography (IOC), routinely rather than selectively, during laparoscopic cholecystectomy (LC) is controversial. Recent findings have shown laparoscopic ultrasound (LUS) to be safe, quick, and effective not only for screening of the bile duct for stones, but also for evaluating the biliary anatomy. This study aimed to evaluate, on the basis of the LC outcome and the cost of LUS and IOC, whether and how much the routine use of LUS would be able to reduce the need for IOC. METHODS: During LC, LUS was used routinely to screen the bile duct for stones and to evaluate the biliary anatomy, whereas IOC was used selectively only when LUS was unsatisfactory or unsuccessful. RESULTS: For 193 (96.5%) of 200 patients, LUS was completed successfully, whereas IOC was needed for 7 patients (3.5%). Bile duct stones were identified in 20 patients (10%). For the detection of bile duct stones, LUS yielded 19 true-positive, 175 true-negative, 0 false-positive, and 1 false-negative results. It had a sensitivity of 95%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 99.4%. The postoperative complications included bile leaks from the liver bed in two patients and a retained bile duct stone in one patient. If IOC had been used selectively in a traditional manner on the basis of preoperative risk factors, IOC would have been needed for 77 patients (38.5%). The total cost of LUS plus IOC for the current 200 patients was 26,256 dollars. The total estimated cost of selective IOC, if it had been performed for the 77 patients, would have been 31,416 dollars. CONCLUSIONS: Routine LUS accurately diagnosed bile duct stones and significantly reduced the need for selective IOC from a potential 38.5% to an actual 3.5% without adversely affecting the outcome of the LC or increasing the overall cost. The routine use of LUS during LC is accurate and cost effective.

Adult↗
PubMed2001

Safety and efficacy of radiofrequency thermal ablation in advanced liver tumors.

HYPOTHESIS: Radiofrequency thermal ablation (RFA) can be performed safely and effectively to control local disease in patients with advanced, unresectable liver tumors. DESIGN, SETTING, AND PATIENTS: Prospective study of 76 patients with unresectable liver tumors who underwent RFA at a private tertiary referral hospital. INTERVENTIONS: Ninety-nine RFA operations were performed to ablate 328 tumors. MAIN OUTCOME MEASURES: Complications and local recurrence. RESULTS: There was 1 death (1%), major complications occurred in 7 operations (7%), and minor complications occurred in 10 operations (10%). Local recurrence was identified in 30 tumors (9%) at a mean follow-up of 15 months. Size (P<.001), vascular invasion (P<.001), and total volume ablated (P<.001) were associated with recurrence but the number of tumors was not (P =.39). CONCLUSION: Radiofrequency thermal ablation provides local control of advanced liver tumors with low recurrence and acceptable morbidity.

Adult↗
PubMed2000

Simple laparoscopic ultrasound technique for prevention of bile duct injuries.

BACKGROUND: Bile duct injuries are serious complications of laparoscopic cholecystectomy. Laparoscopic ultrasonography (LUS) has been utilized over the last several years to screen for bile duct calculi and to delineate biliary anatomy. We have found a simple LUS scanning technique that can be useful for preventing bile duct injuries. METHOD: After initial scanning for screening, laparoscopic dissection is continued, isolating the cystic duct. If necessary, scanning can be performed to assure the location of the cystic duct before clipping. After clips are applied to the cystic duct, prior to its incision or transection, LUS is repeated to examine the cystic and bile ducts. RESULTS: This postclipping study can confirm that the clips are applied to the cystic duct and that the hepatic and common bile ducts are intact without occlusion. CONCLUSION: This additional LUS scanning maneuver is simple and quick and may help prevent bile duct injuries.

Bile Ducts↗
PubMed1999

Laparoscopic ultrasonography versus operative cholangiography during laparoscopic cholecystectomy: review of the literature and a comparison with open intraoperative ultrasonography.

BACKGROUND: Laparoscopic ultrasonography (LUS) has been used increasingly over the last several years as a new imaging modality. To define the role of LUS during laparoscopic cholecystectomy, we evaluated LUS by prospectively comparing it with operative cholangiography (OC), by reviewing the literature on LUS, and by retrospectively comparing it with intraoperative ultrasonography performed during open cholecystectomy. STUDY DESIGN: LUS and OC were compared prospectively in 100 consecutive patients during laparoscopic cholecystectomy. The success rate of examination, the time required, the accuracy in diagnosing bile duct calculi, and the delineation of biliary anatomy were evaluated. RESULTS: The success rate of examination was 95% for LUS and 92% for OC. The main reason for unsatisfactory LUS was incomplete visualization of the distal common bile duct. The time required was 8.2 minutes for LUS and 15.9 minutes for OC (p<0.0001). Nine patients had bile duct calculi. LUS had one false-negative result and OC had two false-positives and one false-negative. The accuracies of LUS and OC were comparable except for a slightly better positive predictive value of LUS (100% versus 77.8%; p>0.1). In a literature review, 12 recent prospective studies comparing LUS and OC and three studies on open intraoperative ultrasonography were reviewed. Twelve studies of LUS with a total of 2,059 patients demonstrated results similar to the present study. The success rate was 88% to 100% for both tests. The time for LUS was approximately 7 minutes, about half of the time needed for OC. Overall, LUS was associated with fewer false-positive results than OC; the positive predictive value and specificity of LUS were better, while the sensitivity and negative predictive value of LUS and OC were comparable. OC detected ductal variations or anomalies more distinctly than LUS. Compared with open intraoperative ultrasonography, LUS had a slightly lower success rate and required a slightly longer time because it was technically more demanding, but the two procedures had a similar accuracy for diagnosing bile duct calculi. CONCLUSIONS: Because of their different advantages and disadvantages, LUS and OC can be used in a complementary manner. There is a learning curve for LUS because of its technical difficulty. Once learned, however, LUS can be used as the primary screening procedure for bile duct calculi because of its safety, speed, and cost-effectiveness. OC can be used selectively, particularly when ductal anatomic variations or anomalies or bile duct injuries are suspected.

Cholangiography↗
PubMed1999

In vitro B-mode ultrasonographic criteria for diagnosing axillary lymph node metastasis of breast cancer.

Axillary lymph node status is an important factor for staging and treatment planning in breast cancer. Our study was performed in vitro on a node-by-node basis to evaluate the ability of B-mode ultrasonographic images to distinguish metastatic from nonmetastatic nodes. Immediately prior to histologic examination, individual dissected axillary nodes were scanned in a water bath using a 10 MHz B-mode ultrasonographic transducer. Four B-mode features (size, circularity, border demarcation, and internal echo) were evaluated for their ability to distinguish metastatic from nonmetastatic lymph nodes. Lymph node metastasis was indicated by (1) a large size (i.e., a length of the longest axis of 10 mm or greater); (2) a circular shape (i.e., the ratio of the shortest axis to the longest axis between 0.5 and 1.0); (3) a sharply demarcated border compared with surrounding fatty tissue; and (4) a hypoechoic internal echo, with obliteration of the fatty hilum. The sensitivity and specificity were compared for all combinations of features. We examined 84 histologically characterized axillary nodes from 27 breast cancer patients, including 64 nonmetastatic and 20 metastatic nodes. Of the criteria cited, circular shape was the best single feature for distinguishing metastatic from nonmetastatic nodes (sensitivity, 65%; specificity, 73%). The best combination of sensitivity (85%) and specificity (73%) was obtained using the criterion that a lymph node contained cancer when at least three positive features were present. The present in vitro study demonstrated that the sensitivity and specificity of B-mode ultrasonography for diagnosing lymph node metastasis were lower than 90%. Therefore, B-mode ultrasonography may not be an optimal noninvasive screening method for diagnosing axillary lymph node metastasis in breast cancer patients, particularly under in vivo clinical conditions.

Adult↗
PubMed1999

Intraoperative and laparoscopic ultrasound.

The instruments, techniques, clinical applications and results, advantages and limitations of intraoperative ultrasound (IOUS) and laparoscopic ultrasound (LUS) in general surgical oncology are presented based on our experiences and review of publications. IOUS provides remarkable benefits in acquisition of accurate diagnostic information, particularly in tumor staging and resectability, and thereby in intraoperative decision making during hepatobiliary, pancreatic, and endocrine surgery. In addition, various surgical procedures are guided or assisted by IOUS. A latest modality of IOUS is LUS, which can provide similar valuable information and compensate for the limitation of laparoscopy. LUS will demonstrate great promise as an adjunct to laparoscopic exploration or surgery.

Biliary Tract Neoplasms↗
PubMed1998

Localization and surgical treatment of pancreatic insulinomas guided by intraoperative ultrasound.

BACKGROUND: Approximately 20% to 60% of insulinomas cannot be localized preoperatively, and 10% to 20% cannot be found even during surgery. The operative complications associated with the blind surgical explorations are relatively high. METHODS: Between January 1987 and December 1995, intraoperative ultrasound was used to localize insulinomas and guide surgical procedures in 28 patients. RESULTS: Insulinomas were found by intraoperative systematic palpation in 24 patients (85.7%), while intraoperative ultrasound localized the tumors in 27 patients (96.4%). By the combination of these two techniques, all tumors were discovered. The surgical procedures were guided by intraoperative ultrasound. The operative complication rate was 14.3%. CONCLUSION: Intraoperative ultrasound can accurately localize insulinoma, and delineate the spatial relationship between tumor and vital structures, such as pancreatic duct, common bile duct, and critical blood vessels. It can thereby help to increase the successful rate of surgery and avoid unnecessary blind pancreatectomy.

Adolescent↗
PubMed1998

In vitro investigation of lymph node metastasis of colorectal cancer using ultrasonic spectral parameters.

Lymph node involvement is one of the major factors affecting the prognosis of colorectal cancer. Various imaging methods, including ultrasound and computed tomography, are not sufficiently sensitive or specific for reliably determining lymph node involvement. We investigated the feasibility of using ultrasonic tissue characterization (UTC) based on spectrum analysis of backscattered echo signals for diagnosing lymph node metastasis of colorectal cancer in vitro. Forty lymph nodes, including 17 metastatic and 23 nonmetastatic nodes, from 11 colorectal cancer operations were investigated. Lymph nodes were scanned using a clinical instrument; B-mode imaging was performed for each lymph node, and radiofrequency (RF) data were acquired. The UTC parameters, slope and intercept, were calculated from the normalized power spectrum of the backscattered echo signals from each lymph node. The mean values of UTC parameters of metastatic and nonmetastatic lymph nodes were compared. The accuracy of UTC in distinguishing metastatic from nonmetastatic lymph nodes was calculated using discriminant analysis. Receiver operating characteristic (ROC) analysis was performed to compare the classification efficacy of UTC and B-mode ultrasound. UTC parameters demonstrated a significant difference in parameter values between metastatic and nonmetastatic lymph nodes. The overall accuracy in diagnosing the lymph node metastasis was 87.5% for UTC and 77.5% for B-mode ultrasound. ROC analysis produced an ROC curve area of 0.92 or 0.89 for UTC (depending on the performance-assessment algorithm) and 0.84 for B-mode ultrasound, which indicated that UTC performed markedly better than B-mode ultrasound in diagnosing metastatic lymph nodes. The advantages of UTC over conventional B-mode ultrasound in discriminating metastatic lymph nodes from nonmetastatic lymph nodes are extremely encouraging, and warrant an in vivo UTC study.

Aged↗
PubMed1998

In vitro diagnosis of axillary lymph node metastases in breast cancer by spectrum analysis of radio frequency echo signals.

Axillary lymph node status is of particular importance for staging and managing breast cancer. Currently, axillary lymph node dissection is performed routinely in cases of invasive breast cancer because of the lack of accurate noninvasive methods for diagnosing lymph node metastasis. We investigated the diagnostic ability of ultrasonic tissue characterization based on spectrum analysis of backscattered echo signals to detect axillary lymph node metastasis in breast cancer in vitro compared with in vitro B-mode imaging. Immediately after surgery, individual lymph nodes were isolated from axillary tissue. Each lymph node was scanned in a water bath using a 10-MHz instrument, and radio frequency data and B-mode images were acquired. Spectral parameter values were calculated, and discriminant analysis was performed to classify metastatic and nonmetastatic lymph nodes. Forty histologically characterized axillary lymph nodes were enrolled in this study, including 25 nonmetastatic and 15 metastatic lymph nodes. A significant difference existed in the spectral parameter values (slope and intercept) for metastatic and nonmetastatic lymph nodes. Spectral parameter-based discriminant function classification of metastatic vs. nonmetastatic lymph nodes provided a sensitivity of 93.3%, specificity of 92.0%, and overall accuracy of 92.5%. In comparison, B-mode ultrasound images of in vitro lymph nodes provided a sensitivity of 73.3%, specificity of 84.0%, and overall accuracy of 80.0%. Receiver operating characteristic (ROC) analysis comparing the efficacy of both methods gave an ROC curve area of 0.9888 for spectral methods, which was greater than the area of 0.8980 for B-mode ultrasound. Hence, this in vitro study suggests that the diagnostic ability of spectrum analysis may prove to be markedly superior to that of B-mode ultrasound in detecting axillary lymph node metastasis in breast cancer. Because of these encouraging results, we intend to conduct an investigation of the ability of spectral methods to classify metastatic axillary lymph nodes in vivo.

Adult↗
PubMed1998

History of intraoperative ultrasound.

Intraoperative ultrasound (IOUS) using A-mode or non-real-time B-mode imaging started in the 1960s; however, it was not widely accepted mainly because of difficulty in image interpretation. In the late 1970s, IOUS became one of the topics in the surgical communities upon the introduction of high-frequency real-time B-mode ultrasound. Special probes for operative use were developed. In the 1980s, all over the world the use of IOUS spread to a variety of surgical fields, such as hepatobiliary pancreatic surgery, neurosurgery, and cardiovascular surgery. IOUS changed hepatic surgery dramatically because IOUS was the only modality that was capable of delineating and examining the interior of the liver during surgery. After 1990, color Doppler imaging and laparoscopic ultrasound were incorporated into IOUS. Currently, IOUS is considered an indispensable operative procedure for intraoperative decision-making and guidance of surgical procedures. For better surgical practice, education of surgeons in the use of ultrasound is the most important issue.

Australia↗
PubMed1998

Laparoscopic ultrasound: a valuable adjunct to laparoscopic surgery.

Laparoscopic ultrasound represents a recent merger in the laparoscopic technology and intraoperative ultrasound and shows a diagnostic accuracy higher than preoperative studies. Laparoscopic ultrasound can be used during laparoscopic cholecystectomy to screen the bile duct. It is particularly useful for diagnosing and staging malignancies, including hepatobiliary, pancreatic and gastroesophageal cancers. By demonstrating the interior of organs and deep structures, it can compensate for the limitation of laparoscopic examination. Laparoscopic ultrasound will become a valuable adjunct to laparoscopic surgery.

Combined Modality Therapy↗
PubMed1998

Laparoscopic inguinal herniorrhaphy: the new gold standard of hernia repair?

The surgical treatment of the common inguinal hernia has been one of the most analyzed and debated topics in medicine. Recently, with the success of laparoscopic cholecystectomy, interest in minimally invasive surgical techniques has led to it's application for inguinal hernia repair. Current laparoscopic herniorrhaphies are based on the principles of conventional open preperitoneal repairs and are classified into two types: 1) transabdominal preperitoneal repair (TAPP) and 2) totally extraperitoneal repair (TEP). Common advantages to both techniques include a decrease in postoperative pain, earlier return to normal activity, and improved cosmesis. Both laparoscopic techniques have the disadvantage of requiring general or regional anesthesia and increased procedural costs. Lastly, there is a concern that laparoscopic hernia repair has not been around long enough to know the risk of late recurrences. Laparoscopic herniorrhaphy, however, is a viable alternative to standard open inguinal hernia repair.

Hernia, Inguinal↗
PubMed1997

Malignant pleural mesothelioma diagnosed after chest trauma.

Two patients who presented with persistent pulmonary symptoms after chest trauma and were diagnosed to have malignant pleural mesothelioma are described. The symptoms, more than expected from trauma, prompted earlier diagnosis of this underlying disease. The possibility of unknown preexisting diseases should always be considered in posttraumatic patients with unusual presentations.

Adult↗
PubMed1996

Technique of laparoscopic ultrasound examination of the liver and pancreas.

Since the introduction of a recent laparoscopic ultrasound (LU), the value of this modality in examining the liver and pancreas has been reported. However, a precise scanning technique of LU has not previously been described. Based on our experience with intraoperative ultrasound during laparotomy, we have developed a technique for complete examination of the entire organs using a rigid LU probe. A 7.5-MHz rigid probe, 10 mm in diameter, was employed. The scanning was performed through three trocar ports: right subcostal, subxiphoid, and umbilical. For the liver, the subcostal scanning provided fundamental transverse views. The subxiphoid and umbilical scanning delineated the areas unable to be imaged by the subcostal scanning. For the pancreas, the subcostal and umbilical scanning demonstrated longitudinal and transverse views, respectively. The subxiphoid scanning enhanced examination of the pancreatic head. Three basic probe maneuvers (advancement-withdrawal, lateral movement, and rotation) and various scanning techniques (contact, probe-standoff, and compression scanning) should be utilized appropriately. With a rigid probe, complete LU examination of the liver and pancreas is possible using these techniques. We believe the present scanning method will help more surgeons learn LU.

Humans↗