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Biomedical subjects

N C Cowan

Publications and source records attributed to N C Cowan.

16 recordsLinked to original sources
PubMed2005

Retrograde or antegrade double-pigtail stent placement for malignant ureteric obstruction?

AIM: To determine the optimum approach for double-pigtail stent placement in malignant ureteric obstruction. PATIENTS AND METHODS: Retrograde stent placement was attempted in a consecutive series of patients presenting with malignant ureteric obstruction. If retrograde stent placement was unsuccessful, percutaneous nephrostomy was performed immediately followed by elective antegrade stent placement. Identical digital C-arm fluoroscopy for image-guidance and conditions for anaesthesia and analgesia were employed for both retrograde and antegrade procedures. Identical 8 Fr (20-26 cm) double-pigtail hydrophilic coated stents were used for each approach. RESULTS: Retrograde placement was attempted in 50 ureters in 30 patients {19 male, 11 female, average age 61.4 yr (range 29-90 yr)} over a 24-month period. The success rate for retrograde ureteric stent placement was 50% (n = 25/50). Technical failures were due to failure to identify the ureteric orifice (n = 22), failure to cross the stricture (n = 1), failure to pass the stent (n = 1) and failure to pass a 4 Fr catheter (n = 1). Antegrade placement was attempted in 25 ureters with a success rate of 96% (n = 24/25). Failure in the one case was due to inability to cross an upper third stricture secondary to pyeloureteritis cystica. CONCLUSION: It is suggested that retrograde route should be the initial approach if imaging shows no involvement of ureteric orifice (UO), when nephrostomy is technically very difficult or in cases of solitary kidney. The antegrade route is preferred if imaging shows tumour occlusion of the UO or if there is a tight stricture very close to the uretero-vesical junction (UVJ) making purchase within the ureter difficult for crossing the stricture.

Adult↗
PubMed2004

Multislice CT urography: state of the art.

Recent improvements in helical CT hardware and software have provided imagers with the tools to obtain an increasingly large number of very thin axial images. As a result, a number of new applications for multislice CT have recently been developed, one of which is CT urography. The motivation for performing CT urography is the desire to create a single imaging test that can completely assess the kidneys and urinary tract for urolithiasis, renal masses and mucosal abnormalities of the renal collecting system, ureters and bladder. Although the preferred technique for performing multislice CT urography has not yet been determined and results are preliminary, early indications suggest that this examination can detect even subtle benign and malignant urothelial abnormalities and that it has the potential to completely replace excretory urography within the next several years. An important limitation of multislice CT urography is increased patient radiation exposure encountered when some of the more thorough recommended techniques are utilized.

Contrast Media↗
PubMed2002

A radiation perspective for treating loin pain in pregnancy by double-pigtail stents.

OBJECTIVE: To review the risks of placing double-pigtail stents during pregnancy in women presenting with loin pain associated with hydronephrosis. PATIENTS AND METHODS: A consecutive series of women presenting with loin pain and hydronephrosis in pregnancy were treated with double-pigtail ureteric stents. A flexible cystoscope was used to identify the ureteric orifice and to pass a guidewire into the renal pelvis under fluoroscopic guidance. Stents were placed using the exchange technique over a stiff guidewire. Procedures were carried out under none or limited sedoanalgesia. Screening times and radiation dose were recorded. Data were collected for the average uterine radiation dose from a variety of radiological procedures. Previous publications were reviewed to determine the lethal, teratogenic and carcinogenic risk to the developing fetus from radiation exposure. RESULTS: Seven patients referred with symptomatic hydronephrosis during pregnancy were treated. The screening time during placement was minimized. The mean (range) uterus (i.e. fetal) dose was 0.40 (0.03-0.79) mGy. Most radiological procedures involve uterine doses of < 20 mGy, far below the 100 mGy that may result in fetal damage during periods of maximum radiosensitivity. CONCLUSION: Minimized radiation exposure from a range of uroradiological procedures in pregnant women has limited fetal risk. The use of fluoroscopy for symptomatic hydronephrosis during pregnancy allows ureteric stents to be placed safely and reliably. The average excess risk to the fetus from this procedure is 1 in 43 000 of cancer induction and 1 in 100 000 of heritable disease, i.e. very small when compared with the natural incidence. Pregnancy should not exclude the use of appropriate diagnostic radiation exposure and urologists may conduct appropriate diagnostic and therapeutic procedures, taking care to limit X-ray exposure without fear of risk to the developing fetus.

Adult↗
PubMed2002

Fluoroscopy guided retrograde ureteral stent insertion in patients with a ureteroileal urinary conduit: method and results.

PURPOSE: We evaluated retrograde double pigtail stent placement in patients with ureteroileal anastomosis. MATERIALS AND METHODS: Procedures were performed under digital C-arm fluoroscopic guidance and the patient under sedation analgesia. Radiography of the conduit was done to delineate urinary diversion anatomy and identify ureteral reflux. A purpose designed, angled tip catheter was used to direct a straight glide wire across the ureteroileal anastomosis. The glide wire was exchanged for a stiff guide wire for stent placement. We retrospectively evaluated the clinical records of 7 men and 5 women with a mean age of 54.3 years in a 7-year period. In 11 patients a new stent was placed because of ureteroileal stricture in 5, anastomotic leakage in 3, ureterolithiasis in 2 and recurrent malignancy in 1. RESULTS: New stent placement was successful in 10 of the 11 patients (90.9%, 13 of 16 ureters or 81.3%). Stent placement was successful in the 8 ureters in which reflux was noted on radiography of the conduit and in 5 of the 9 (55.6%) in which no reflux was noted. Stent replacement was accomplished in all 22 ureters (6 patients) in which it was attempted. Mean radiological screening time for new stent placement was 13.3 minutes (range 4.7 to 19.7), while for exchange it was 6.4 minutes (range 0.8 to 15.1). There were no immediate complications. CONCLUSIONS: This technique represents a useful approach to the ureter and should be considered an alternative to percutaneous nephrostomy and surgical revision. The approach is also useful for other ureteral procedures, including stone or migrated stent retrieval.

Adolescent↗
PubMed1998

Direct percutaneous transrenal embolization for renal artery injury following percutaneous nephrostomy.

The use is reported of percutaneous transrenal embolization for renal artery injury during percutaneous nephrostomy. If a nephrostomy catheter is seen to transfix the renal pelvis, the possibility of injury to a large renal artery must be considered. The misplaced nephrostomy catheter should be withdrawn over a guidewire. Percutaneous renal artery embolization may enable rapid arrest of life threatening haemorrhage.

Aged↗
PubMed1995

Fluoroscopically-guided retrieval of ureteric stents.

Percutaneous fluoroscopically-guided retrieval of seven dysfunctional ureteric stents was performed in five patients (four male, one female) over an 18 month period. The technical aspects of the procedure are discussed and the preferred method using rigid forceps is described.

Aged↗
PubMed1992

The natural history of sciatica: a prospective radiological study.

This prospective study was set up to record the changes in the intervertebral disc accompanying resolution of sciatica following conservative treatment. Patients presenting with sciatica (n = 165) were examined by computed tomography (CT) of the lumbar spine. Disc lesions were classified into the following groups: herniation, sequestration, generalized bulge and focal bulge. Follow-up CT of the pathological disc was performed in 106 of the 165 patients after 1 year and identical anatomical sections were compared. All patients were initially treated conservatively by the injection of steroid and local anaesthetic at the intervertebral disc/nerve root interface. Of 84 cases of disc herniation and sequestration 64 (76%) showed either complete or partial resolution on follow-up CT examination. Of 22 cases with either a generalized or focal bulge of the disc 18 (82%) were unchanged on follow up. The classical disc herniation in a young patient is the type of disc lesion most likely to show greatest improvement at follow-up CT.

Adolescent↗
PubMed1991

Focal nodular hyperplasia of the liver: a link with sickle cell disease?

Focal nodular hyperplasia is a benign liver tumour that is rare in children. We report the second case of a child with sickle cell disease presenting with symptomatic focal nodular hyperplasia. The possible pathogenesis of focal nodular hyperplasia and the association with sickle cell disease are discussed.

Child↗
PubMed1988

Coronary angioplasty in pregnancy.

Myocardial infarction is rare in pregnancy. A 30 year old white primigravida had an anterior infarct at 20 weeks' gestation, which was followed by troublesome angina. Coronary angiography showed a tight stenosis of the left anterior descending coronary artery. This was treated successfully by percutaneous transluminal coronary angioplasty.

Adult↗
PubMedDate not supplied

Unknown ESUR cases 2004.

The authors present 14 cases from the film interpretation session of the 11th annual meeting of the European Society of Urogenital Radiology presented in September, 2004. The cases demonstrate the imaging findings, differential diagnoses, and clinical relevance of a wide variety of genitourinary tract diseases. The cases include examples of benign and malignant urinary tract neoplasms, inflammatory processes, vascular diseases, traumatic injuries, and congenital anomalies.

Adolescent↗