Uroradiologic interventions

Drainage procedures of the kidney

Antegrade pyelography followed by percutaneous catheter drainage is the method of choice in supravesical urinary obstruction and pyonephrosis if retrograde cystoscopic drainage via the bladder and ureter

is not possible. Pereutaneous nephrostomy has been refined remarkably since the original description by Goodwin and Casey in 1955 with technical success rates of about 98 % and a complication rate of less than 0.5%. With ultrasound and/or fluoroscopic guidance pereutaneous nephrostomy offers a rapid and safe means of relieving hydronephroses or pyogenic obstructions under local anesthesia. Even very sick patients may be treated in order to improve the clinical status for later curative or palliative therapy (Fig. 15). More often pereutaneous nephrostomy now serves as the initial step in a variety of pereutaneous procedures such as antegrade dilation and stenting of the ureter, endourologic stone removal as an adjunct to extracorporeal shock wave lithotripsy (ESWL), percutaneous pyeloand litholysis and treatment of ureteral fistulas etc. (Fig. 16).

Procedures in the ureters and the urethra

Ureteral stenting is indicated for obstruction whether it be benign stricture, malignant encasement or intraluminal blockage and edema (Figs.
15 + 16). Ureteral balloon dilations are performed for postsurgical and anastomotic strictures with good results. Excellent indications for balloon dilation are strictures after ureterotomy, ureterovesical and ureteroileal anastomoses. Patients with recent, benign, cicatricial, traumatic strictures may also benefit from this procedure. In patients with kidney transplants only the anastomotic strictures respond well to balloon dilation. Inflammatory, densely fibrotic strictures and ischemic strictures do not respond to dilation. Congenital pyeloureteral strictures usually do not respond well to dilation in the long term.

Dilation of the prostatic part of the urethra in benign prostatic hyperplasia was developed in the early 80s at the University of Minnesota. In spite of the overall success rate of60 to 70% at two years, the technique is not yet widely used and longer follow-up periods are needed to prove that balloon dilation is a valid alternative to transurethral resection of the prostate (TURP). Implantation of removable and non-removable metallic stents has been tried but the exact role of stents in the management of benign prostatic hyperplasia has not been defined.

The treatment of benign urethral strictures secondary to trauma or inflammation by balloon dilation has not proved to be superior to conventional dilation techniques. Metal stents have been tried successfully by Dick and colleagues but again more long term follow-up is needed to prove its efficacy.

Fallopian tube recanalization

Over the last few years a new technique for hysterosalpingography using a special vacuum cup-type device (hysterocath) has been developed by Thurmond and Rosch. This special instrument allows intubation of the proximal tubal ostium of the uterus using a coaxial catheter system. If injection of contrast material through a 5.5F catheter positioned in the tubal ostium shows obstruction of the proximal fallopian tube this may be recanalized using a guidewire and/or a coaxial 3F catheter (Fig. 17). The technical success rate for recanalizsation of a proximal obstruction

of the fallopian tube is up to 95% followed by an intrauterine pregnancy rate within the first 7 months of 33 %. Fluoroscopic transvaginal fallopian tube catheterisation in patients with proximal tubal obstruction has proved a valuable alternative to surgery and should be the first intervention before the more invasive and more expensive microsurgery.

Christoph Zollikofer