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Biomedical subjects

J L Nosher

Publications and source records attributed to J L Nosher.

At least 19 recordsLinked to original sources
PubMed2001

Radiologic placement of a low profile implantable venous access port in a pediatric population.

PURPOSE: To evaluate the feasibility and complications of placement of a low-profile venous access port in the chest in children requiring long-term venous access. METHOD: A low-profile peripheral arm port (PAS port; Sims Deltec, St. Paul, MN, USA) was implanted in the chest in 22 children over a 4-year period. The mean age of the study group was 6 years (range: 9 months to 20 years). Ports were placed for the administration of chemotherapy, hyperalimentation and frequent blood sampling. Sonographic guidance was used to access the internal jugular or subclavian vein in each case. A review of all inpatient and outpatient charts was undertaken to assess catheter performance and complications. RESULTS: Access to the central venous circulation was successfully achieved in each case without complication. Ports remained implanted for 6579 catheter-days (mean: 299 days). Ten ports have been removed. Of three patients (13%) experiencing device-related infections (0.45 infections/1000 catheter days), two (9.1%) were unresponsive to antibiotics and removed (0.3 infections/1000 catheter days). One port was removed because of pain in the shoulder adjacent to the port implantation site. One port was removed because of difficult access. The final port was removed in order to place a dual-lumen catheter prior to bone marrow transplant. Twelve ports remain implanted. Aspiration occlusion occurred in four patients (18%). Deep venous thrombosis did not occur in any patient. CONCLUSION: Low-profile chest ports placed by interventional radiologists in the interventional radiology suite can be placed in children as safely as traditional chest ports placed in the operating room. The incidence of infection, venous thrombosis and aspiration occlusion is comparable to that of ports placed operatively.

Adolescent↗
PubMed2001

Characterization of radial forces in Z stents.

RATIONAL AND OBJECTIVES: The purpose of this study was to evaluate the effects of variation in design parameters on the resultant radial force. We evaluated the influence of wire gauge, leg length, and number of bends on the radial force produced by z stents and compared these with radial forces produced by commercial stents. A second goal was to develop an engineering model for predicting radial forces generated by z stents. METHODS: Z stents were fashioned by hand using stainless steel wire and solder that connected the ends. The radial force was measured as a function of wire gauge, vessel diameter, leg length, and number of bends and compared with the theoretical values of radial force calculated by combining Castigliano's theorem and the law of Laplace. RESULTS: Theoretically predicted radial forces were within 8% of each observed value of radial force up to 70% spring compression. CONCLUSIONS: These results suggest that the z-stent model can be used to build custom stents with preselected values of radial force for clinical use. In addition, they can be used to design model investigational stents made of similar materials and surface areas to test the effects of radial force on biological response.

Biomechanical Phenomena↗
PubMed1999

Access to occluded infrainguinal bypass grafts with a loopsnare.

Thrombolysis for the treatment of occluded bypass grafts is used in selected clinical circumstances. Unfortunately, a minority of these procedures are technical failures because of the inability to access the occluded graft. We describe a technique that greatly increases the chances of technical success.

Aged↗
PubMed1999

Endovascular stent graft for management of ureteroarterial fistula after orthotopic bladder substitution.

We describe the first case of an ureteroarterial fistula developing after orthotopic neobladder substitution and its minimally invasive management using endovascular stent grafting. We outline the risk factors for the development of ureteroarterial fistulae and trace the evolution of diagnostic and therapeutic modalities used in the management of these life-threatening complications. Minimally invasive management with endovascular stent grafting and exclusion of two pseudoaneurysms in the iliac artery system was performed successfully. After successful endovascular exclusion of two pseudoaneurysms, the patient's hematuria resolved and he recovered fully. Three-dimensional computed tomography performed 3 months later documented a patent aortoiliac arterial system without evidence of pseudoaneurysm or endovascular leak. Ureteroarterial fistula after orthotopic bladder substitution was managed with an endovascular stent graft without the need for extra-anatomical vascular bypass. Early recognition, stabilization, and angiographic evaluation followed by this minimally invasive technique may avoid open operative repair and attendant morbidity.

Cystectomy↗
PubMed1997

Ultrasound characteristics of subdermally implanted Implanon contraceptive rods.

This study was designed to define sonographic characteristics and the optimal sonographic technique for localization of the single rod Implanon system. Diagnostic ultrasonography was performed in eight women who had the Implanon rod implanted in the medial aspect of the upper arm. All implants were scanned in the longitudinal and transverse direction using 3.5 MHz, 5 MHz, and 7.5 MHz linear array transducers. Scanning was performed both directly against the skin and with 2 and 4 cm Kiteco ultrasound stand-off pads. Each image obtained was evaluated for detectability of the Implanon rod and the grade of acoustic shadowing produced by the Implanon rod by two independent observers. Discrepancies in evaluation were adjudicated by a third observer. The Implanon rod implant was not directly identified using the transducer and standoff pad combinations. Implanon rods were indirectly identified as a result of the posterior acoustic shadow cast by the Implanon. Best demonstration was achieved with the 5 or 7.5 MHz transducer and a 2 cm stand-off pad in the transverse direction. Appropriate ultrasonographic technique and familiarity with posterior acoustic shadowing patterns generated by the implant provide a noninvasive method for localization of nonpalpable, single rod implants prior to removal.

Arm↗
PubMed1995

Radiologic diagnosis of cystic fibrosis in adults and children.

RATIONALE AND OBJECTIVES: Most radiologists are familiar with the classic chest radiographic findings of cystic fibrosis (CF) when these occur in children. We hypothesized that given the same findings, a diagnosis of CF would be less likely to be considered in an adult than in a child. METHODS: We compiled 30 pediatric and 28 adult CF chest radiographs and obtained two independent readings on each by different general radiologists among the eight who volunteered to participate as they performed their daily clinical work. The cases were presented to the readers so that they did not know which radiographs were part of the study. The association between the correct diagnosis of CF and whether the patient was an adult or a child was assessed using odds ratios and logistic regression, so that Brasfield score, Schwachman-Kulczycki score, and the patient's sex could also be considered as predictive of correct diagnosis. RESULTS: In 67% of the pediatric cases, at least one of the radiologists considered CF as a possible diagnosis, whereas they considered CF a possibility in only 50% of the adults. Both radiologists suggested the correct diagnosis in 40% of pediatric cases and only 14% of adult cases (p < .05). CONCLUSION: Because the radiographic findings were similar in the two groups of patients according to severity groupings, we believe CF was less commonly considered in the adult patient because of the traditional belief that CF is a childhood disease.

Adolescent↗
PubMed1994

Peritoneal dialysis catheters: repositioning with new fluoroscopic technique.

From April 1990 to December 1992, the authors evaluated a new technique for radiologic manipulation of malfunctioning peritoneal dialysis catheters (PDCs). In 25 patients (16 male and nine female patients, aged 15-81 years), 25 PDCs were fluoroscopically manipulated 38 times for failure to drain (n = 22) or painful dialysis (n = 3). The PDC was backed out of its initial position with use of a wire and stiffener. Immediate success was obtained in 34 of 38 manipulations (89%), 21 manipulations (55%) were successful at 1 week, and durable success (function for more than 1 month or until the catheter was no longer needed) was achieved in 16 manipulations (42%). This is an effective alternative procedure to surgical catheter replacement or hemodialysis.

Adolescent↗
PubMed1994

Tunneled central venous access catheter placement in the pediatric population: comparison of radiologic and surgical results.

PURPOSE: To compare the success and infection rates of radiologic placement with those of surgical placement of tunneled central venous access catheters (TCVACs) in infants and small children. MATERIALS AND METHODS: In 17 pediatric patients, TCVACs were placed with vascular access under ultrasound or fluoroscopic guidance in the radiology department. In 29 other patients, TCVACs were placed with percutaneous puncture or surgical cutdown in the surgery department. RESULTS: Two (11%) of 18 attempts at radiologic placement were unsuccessful; six (38%) of the 16 radiologically placed catheters necessitated removal because of dislodgment, malfunction, or infection; six (38%) were electively removed; and four (25%) still function. Eight (23%) of 35 attempts at surgical placement were unsuccessful; 17 (63%) of the 27 surgically placed catheters required removal because of dislodgment, malfunction, or infection; nine (33%) were electively removed; and one (4%) still functions. CONCLUSION: The success and infection rates of radiologic placement of TCVACs were similar to those of surgical placement. Radiologic placement required fewer attempts and was slightly less expensive.

Adolescent↗
PubMed1993

Operative tube versus percutaneous cholecystostomy for acute cholecystitis.

The records of 26 patients who underwent cholecystostomy procedures for presumed acute cholecystitis during a 6-year period were reviewed. Nine patients had operative tube cholecystostomy (OC), and 17 patients had radiologic percutaneous cholecystostomy (PC). A correct diagnosis of acute cholecystitis was made in 22 of 26 patients (84%), including 14 of 17 PC patients and 8 of 9 in the OC group. The rate of resolution of cholecystitis was the same in each group (75% OC versus 78% PC). APACHE II scores prior to treatment were significantly higher in OC patients (20.9 OC versus 12.4 PC, p < 0.01). There were 5 deaths, including 3 in the OC groups and 2 in the PC group. Nonfatal complications were more frequent in the PC group. Two of the 14 correctly diagnosed PC patients (14%) subsequently required emergency cholecystectomy for persistent biliary sepsis, and 6 patients (43%) required at least 1 tube exchange for occlusion or dislodgement. Overall, only 5 of the 14 patients (36%) in the PC group were successfully treated without complications compared with 5 of 8 patients (63%) in the OC group. Despite its theoretical advantages, PC was no more effective than OC in the treatment of acute cholecystitis. These data suggest that OC remains a viable treatment option in critically ill patients with acute cholecystitis.

Acute Disease↗