14. Watkinson A, Ellul], Entwistle K, et a1. Plastic-cov­ered metallic endoprostheses in the management ofoesophageal perforation in patients with oesopha­geal carcinoma. Clin Radiol 1995; 50:304-309.

15. Keymling M, Wagner H-J, Vakil N, Knyrim K. Reliefof malignant doudenal obstruction by percutaneousinsertion of a metal stent. Gastrointestinal Endos­copy 1993; 39:439-441.

16. Scott-Mackie P, Morgan R, Farrugia M, Glynos M,Adam A. Malignant duodenal obstruction: a role formetallic stents. Br J Radiol (In Press).

8:50 am

Management of Chronic Ureteral ObstructionParvati Ramchandani, MDURETERAL obstruction comes to clinical attention whenpatients present with flank or abdominal pain, azotemiaor urinary tract infection or when imaging studies dem­onstrate hydroureteronephrosis; the etiology spans thespectrum from neoplastic disease to benign causes.

Neoplastic obstruction usually occurs in the setting ofadvanced malignant disease and it can be related eitherto primary urothelial neoplasms or to extrinsic compres­sion by primary or metastatic retroperitoneal or pelvicmalignancies. The goal of treatment in these patients isto provide renal drainage so that renal function can bemaintained.

Benign ureteral strictures are most apt to be iatro­genic in origin with urological, gynecological and gen­eral surgical procedures accounting for 42%, 34%, 34%,and 24% of ureteral injuries respectively in a recent series(1). The widespread use of upper urinary tract endos­copy for the minimally invasive diagnosis and treatmentof a myriad of pathologies has had the paradoxical resultof making endourological procedures the single mostcommon cause of ureteral injuries, which reportedlyoccur in 3%-18% of patients undergoing ureteroscopy(1,2). In Selzman's series (1), 79% of urological ureteralinjuries occurred during an endoscopic procedure (at­tempted stone removal being the most frequent), while21% occurred during an open procedure such as uretroor nephrolithotomy, radical retropubic prostatectomy, orlymph node dissection. Abdominal hysterectomy andsalpingo oopherectomy accounted for 86% of the gyne­cological injuries and colorectal surgery accounted for67% of all general surgical injUries. Laparoscopic surgeryis also becoming an increasingly frequent cause of iat­rogenic ureteral injuries (3).

Other causes of ureteral strictures include recurrentstone passage in patients with chronic calculous disease,penetrating abdominal trauma, particularly high velocitygun shot wounds, radiation therapy, and infections suchas tuberculosis and bilharziasis. Strictures that occur atthe uretero-enteral anastomotic site in patients with uri­nary diversion are particularly refractory to treatment.

Therapeutic options in the management of chronicureteral obstruction range from percutaneous nephros-

tomy drainage alone to ureteral stenting, either denovoor preceded by balloon dilation.

Percutaneous nephrostomy is almost universally suc­cessful in draining obstructed, dilated kidneys, allowingfor immediate renal decompression in patients with ob­struction complicated by urosepsis or azotemia (4,5). In

ureteral obstruction due to benign disease, the decisionto perfonn the procedure is straightforward. In patientswith terminal malignancies where the obstruction is ir­remediable, the need for drainage is likely to be penna­nent. The burden posed by the presence of a drainagecatheter should be carefully weighed against the benefitof extending life for a few months, a dilemma thatshould be openly discussed with the referring physician,the patient and the family. Long-tenn survival after pal­liative diversion for malignant ureteral obstruction ispoor and determined largely by the type and stage of theunderlying neoplasm, and its potential for further treat­ment. Median survival after nephrostomy drainage inone group of 77 patients with pelvic malignant diseasewas 26 weeks (6) and only 25% of patients were alive at1 year in another series (7). Unless aggressive chemo­therapeutic treatment is planned, unilateral drainageusually suffices and bilateral drainage confers no addi­tional benefit. However, patients with hormone respon­sive prostate cancer tend to live longer than patients withother pelvic malignancies and bilateral drainage may bea preferable option in these patients, particularly if theyare young (8).

Percutaneous nephrostomy should not be the firstprocedure to be considered for renal drainage unless thepatient has urosepsis; it should ideally be reserved forpatients in whom retrograde renal drainage is eitherunsuccessful or infeasible. Locking loop 8- or 10-F drain­age catheters are the catheters of choice for long-termdrainage with a reported dislodgment rate of less than1% (4).

Ureteral StentingUreteral stent placement provides the benefits of urinedrainage and diversion without the necessity for a drain­age bag and is therefore preferred to nephrostomy drain­age in most patients. However, if the urinary bladder ismarkedly contracted or diseased (as in patients withradiation cystitis, hemorrhagic cystitis, tuberculous cys­titis or tumor invasion of the bladder) or in patients withurinary incontinence or vesical fistulae, percutaneousnephrostomy drainage is preferable to ureteral stenting.Nephrostomy drainage may also be the only option inpatients with extensive bulky pelvic disease that causesureteric or bladder compression-antegrade urine drain­age often fails in such patients despite patency of theureteral stent, presumably due to a decrease in the pres­sure differential between the renal pelvis and the blad­der.

Ureteral stents can be inserted in one of three ways:(1) percutaneously (antegrade), (2) retrograde transure-

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thral approach, and (3) retrograde transconduit ap­proach.

Percutaneous, antegrade stent insertion is performed

when retrograde insertion fails or is not possible. Twokinds of ureteral stents that can be percutaneouslyplaced are used currently: internal stents (double J ordouble pigtail) and external-internal stents(nephroureteral stents). In the latter, a segment of thecatheter protrudes from the flank. It is capped externallyto allow antegrade urine drainage through holes in the

catheter at the level of the renal pelvis and the urinarybladder. External-internal stents can be easily changedpercutaneously and can be irrigated to prolong catheterpatency. In some patients, they are more effective at

draining urine antegrade, even when a double pigtailstent fails to drain adequately, possibly due to the largerside holes. Nephroureteral stents are indicated in pa­tients in whom retrograde stent exchange would bedifficult due to bladder disease or distortion and in pa­tients in whom stent placement is anticipated to be onlyfor a short period (as after ureteral dilation or stoneretrieval) .

Internalized stents do not protrude from the flank, anobvious advantage. Successful antegrade placement re­quires favorable nephrostomy access through an upper

pole or interpolar calyx, liberal use of transrenal sheathsto buttress the nephrostomy track and use of appropri­ately stiff guide

patency should be confirmed at 3 months with excretoryurography, cystography, or radionuclide urography.Poor stent function can be related to stent occlusion,poor emptying of the urinary bladder, or to markedureteral encasement by tumor.

The patients should be made aware that they have anindwelling foreign body that should be changed every 6months. It is advisable to maintain a stent registry wherethe date of insertion and type of stent is recorded forevery patient and a reminder for stent exchange sent tothe patient at the appropriate time 05,16). Stent ex­change can be performed either by a urologist in con­junction with cystoscopy or by a radiologist in a retro­grade periurethral fashion. Stents that have been in situfor prolonged periods can encrust, as well as fragment.

References1. Selzman AA, Spirnak P]. Iatrogenic ureteral injuries:

a 20-year experience in treating 165 injuries. J urol1996; 155:878-881.

2. Goldfischer ER, Gerber GS. Endoscopic manage­ment of ureteral strictures. J uro11997; 157:770-775.

3. A~simos DG, Patterson LC, Taylor CL. Changing in­cidence and etiology of iatrogenic ureteral injuries.J Urol 1994; 152:2240-2246.

4. Farrell TA, Hicks ME. A review of radiologicallyguided percutaneous nephrostomies in 303 patients.JVIR 1997; 8:769-774.

5. Leroy A]. Percutaneous nephrostomy: techniquesand instrumentation. In: Pollack HM, ed. ClinicalUrography. Philadelphia. WB Saunders, 1990, 2725­

2738.

6. Lau MWM, Temperley DE, Mehta S, Johnson R],Barnard RJ, Clarke NW. Urinary tract obstruction andnephrostomy drainage in pelvic malignant disease.Be] Urol 1995; 76:565-569.

7. Hoe ]WM, Tung KH, Tan EC. Reevaluation of indi­cations for percutaneous nephrostomy and interven­tional uroradiologic procedures in pelVic malig­nancy. Br J Radiol 1993; 71:469-472.

8. Chapman ME, Reid ]H. Use of percutaneous ne­phrostomy in malignant ureteric obstruction. Br ]Radiol 1991; 64:318-320.

9. Babel SG, Winterkorn KG. Retrograde catheterisa­tion of the ureter without cystoscopic assistance:preliminary experience. Radiology 1993; 187:547­549.

10. Banner MP, Amendola MA, Pollack HM. Anasto­mosed ureters: fluoroscopically guided transconduitretrograde catheterisation. Radiology 1989; 170:45­49.

11. Meretyk S, Clayman RV, Kavoussi LR, KramolowskyE\!, Picus DD. Endourological treatment of uret­eroenteric anastomotic strictures: long-term [01­lowup. J Urol 1991; 145:723.

12. Walther P], Robertson CN, Paulson DF. Lethal com­plications of standard self-retaining ureteral stents inpatients with ileal conduit urinary diversion. ] Urol

1985; 133:851.

13. Lugmayr HF, Pauer W. Wallstents for the treatmentof extrinsic malignant ureteral obstruction: midtermresults. Radiology 1996; 198:105-108.

14. Pollak ]S, Rosenblatt MM, Egglin TK, Dickey KW,Glickman M. Treatment of ureteral obstruction withthe Wallstent endoprosthesis: preliminary results.

]VIR 1995; 6:417-425.

15. Somers W). Management of forgotten or retainedindwelling ureteral stents. urology 1996; 47:431­

435.

16. Monga M, Klein E, Castaneda-Zuniga WR, Thomas R.

The forgotten indwelling ureteral stent: A urologicaldilemma.] Uro11995; 153:1817-1819.

9:10 am

Management of Malignant Pleural EffusionsAlben A. Nemcek, Jr., MD

Learning objectives: As a result of attending the ple­nary session, the attendee will be able to: (1) Give rea­sons for the imponance of preliminary imaging andlaboratory workup of malignant pleural effusions priorto therapy. (2) Discuss indications for and factors af­fecting success ofpleurodesis for malignant pleural ef­fusions. (J) Understand prinCiples of imaging-guidedchest tubeplacementfor malignantpleural effusions. (4)Discuss aspects of chest tube management relevant topleurodesis. (5) Discuss in general terms other forms ofcurrent therapy for malignant pleural effusions.

PLEURAL effusions are a common problem in patientswith malignant neoplasms. The annual incidence ofpleural effusions associated with malignant disease hasbeen estimated at 200,000 cases. Malignant disease is thesecond most common cause overall of exudative pleuraleffusions (after parapneumonic effusions) and the mostcommon cause in adults over 60 years of age; it is alsoprobably the most common cause of exudative pleuraleffusions subjected to thoracentesis. While virtually anymalignancy can result in malignant effusion, the majority(>75%) are due to lung or breast carcinoma or to lym­phoma 0-4).

Although they can represent the earliest manifesta­tion of a malignancy, or the earliest sign of its recurrence,malignant effusions are often an indication of wide­spread disease and a poor clinical prognosis. Manage­ment of pleural effusions associated with malignancydepends on multiple factors, including the type andstage of malignancy and the exact etiology of the effu­sion. In patients with advanced disease, optimal man­agement remains controversial. However, the goal ofmanagement at this point is not: it is palliative, anddirected toward the debilitating dyspnea that commonlyaccompanies malignant effusions 0-8).

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