SEMINARS IN INTERVENTIONAL RADIOLOGY VOLUME 17, NUMBER 4 2000

Percutaneous Nephrostomy

Michael M. Maher, M.D., Timothy Fotheringham, M.D., and Michael J. Lee, M.D.

ABSTRACT

Percutaneous nephrostomy (PCN) is now established as a safe and effective early treatment for patients with urinary tract obstruction. In experienced hands, PCN is usually successful and is associated with low complication rates. This article discusses all aspects of PCN, including the indications and contraindications to PCN, patient preparation, the techniques employed for gaining access to the urinary tract, and placement of the PCN tube. In addition, we discuss the complications of PCN and possible ways of avoiding them, as well as the care of patients following PCN.

Keywords: Percutaneous nephrostomy, renal failure, pyonephrosis

Urinary tract obstruction invariably requires eral anesthesia is avoided and surrounding organs treatment, and indications for immediate or urgent can be imaged and avoided during PCN. In expert intervention include clinical and laboratory signs of hands, PCN is associated with a major complication underlying sepsis and clinical or radiological signs rate of 4 to 5%4 and a minor complication rate of of pyonephrosis. Urgent intervention is also manda- approximately 15%.1 PCN is usually faster, less ex- tory for the treatment of life-threatening biochemi- pensive, and less likely to be associated with compli- cal abnormalities associated with the rapid onset of cations than is surgery.5 In the current era, PCN renal failure. also allows access to the urinary tract for more In the past decade, image-guided PCN has re- definitive treatment of underlying pathologies such placed the conventional surgical approach for the as percutaneous nephrolithotomy (PCNL) for temporary drainage of urinary tract obstruction. treating urinary tract calculi and the placement of PCN is now established as a safe and effective initial ureteric stents for treating malignant urinary tract treatment for patients with urinary tract obstruc- obstruction. The type of image guidance used dur- tion.1–3 The percutaneous approach has many ad- ing PCN frequently varies depending on imaging fa- Downloaded by: University of Florida. Copyrighted material. vantages over surgery, including the fact that gen- cilities available at the institution and, more impor-

Objectives Upon completion of this article, the reader will understand how to perform percutaneous nephrostomy safely and avoid complications. Accreditation Tufts University School of Medicine is accredited by the Accreditation Council for Continuing Medical Education to sponsor continuing medical education for physicians. TUSM takes full responsibility for the content, quality, and scientific integrity of this continuing education activity. Credit The Tufts University School of Medicine designates this educational activity for a maximum of 1.0 hours credit toward the AMA Physicans Recognition Award in category one. Each physician should claim only those hours that he/she actually spent in the educational activity.

Department of Radiology, Beaumont Hospital and the Royal College of Surgeons Medical School, Dublin, Ireland

Reprint requests: Michael J. Lee, Department of Radiology, Beaumont Hospital and the Royal College of Surgeons Medical School, Beaumont Hospital, Dublin 9, Ireland.

Copyright © 2000 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662. 0739-9529,p;2000,17,04,329,340,ftx,en; sir00085x. 329 SEMINARS IN INTERVENTIONAL RADIOLOGY VOLUME 17, NUMBER 4 2000

tantly, the preference of the operator. Modern quently aid in deciding the optimal timing of the nephrostomy is usually performed in the fluo- procedure and can optimize the patient’s biochemi- roscopy suite using a combination of ultrasound cal and other parameters prior to the procedure. It and fluoroscopic guidance. However, in recent is important that the urologist is available should times both computed tomography (CT)6,7 and mag- any complications occur that might require urgent netic resonance imaging (MRI)8 have been added surgical intervention. to the list of imaging modalities used to facilitate Prothrombin time and activated partial throm- PCN. boplastin time estimations should be performed prior to PCN, and, if abnormal, attempts should be made to optimize coagulation and other hemato- INDICATIONS logic parameters prior to the procedure.9–11 The procedure should be explained to the patient and The most common indications for PCN in- his or her relatives prior to the procedure, and po- clude benign obstruction resulting from ureteric tential complications such as hemorrhage, urinary stones and malignant obstruction resulting from leakage, septicaemia, and death should be men- carcinoma of the bladder, prostate, and cervix. tioned prior to the examination. Good peripheral Ureteric obstruction can also result from extrinsic intravenous access should be ensured prior to the compression of the ureters by metastatic deposits procedure. Many authors initially recommended from carcinoma of the uterus, colon, cervix, breast, the use of antibiotics before PCN in instances in and abdominal lymphoma. Another common indi- which the patient was at high risk of sepsis, in other cation for PCN is iatrogenic damage to the ureter, words, suspected pyonephrosis.4,5 More recently, an- which most commonly occurs following abdominal tibiotics have been recommended for all patients re- hysterectomy or right or left hemicolectomy or fol- gardless of preprocedure risk profile, with antibiotic lowing instrumentation of the ureter during endo- dosage depending on the perceived risk of sepsis.4 scopic treatment of ureteric stones. Other less com- Our practice is to prescribe preprocedure antibi- mon indications for PCN include the relief of otics to the patients with leukocytosis or fever. We do terminal vesicovaginal fistula and ureteral fistulae. not routinely give antibiotics for noninfected pa- The most common indication for emergency tients. A broad-spectrum cephalosporin is suitable nephrostomy is acute sepsis is an obstructed urinary for administration prior to the procedure. When tract secondary to pyonephrosis. The other most fungal infection is suspected, this should also be cov- common reason for emergency nephrostomy is ered by the antibiotic regimen administered prior to acute renal failure secondary to acute obstructive the procedure. For sedation and pain relief, we use uropathy. The most worrying biochemical abnor- midazolam and fentanyl in incremental amounts of mality associated with renal failure, which can lead 1 mg and 50 to 100 g, respectively. Patients are to a life-threatening cardiac arrhythmia, is severe monitored using blood pressure and pulse oximetry hyperkalaemia. If there is no evidence of either apparatus throughout the procedure.

acute sepsis or acute hyperkalaemia, PCN can be A nurse trained in the monitoring of critically Downloaded by: University of Florida. Copyrighted material. performed on the next elective interventional list. ill patients should be available during the proce- dure to monitor blood pressure and pulse oximeter readings. PATIENT SELECTION AND PREPARATION

In most cases of acute urinary tract obstruc- ANTEGRADE PYELOGRAPHY tion, PCN is used as a temporizing measure until definitive medical or operative correction of the Antegrade pyelography involves the insertion cause of obstruction can be carried out. The aim of of a needle into the pelvicalyceal system and the PCN is immediate treatment of acute pyonephrosis opacification of the collecting system with contrast or acute hyperkalemia, allowing stabilization of the material to clearly delineate the pelvicalyceal sys- critically ill patient prior to definitive investigation tem and ureter.12 The routine performance of ante- of the cause of ureteric obstruction. The placement grade pyelography has two main advantages. Firstly of a PCN catheter allows the kidneys to regain func- the pelvicalyceal system can be opacified and dis- tion and relieves pyonephrosis, septicemia, and as- tended, which greatly aids access to the pelvi- sociated biochemical abnormalities. calyceal system. Secondly the presence of the ante- The treatment of acute urinary tract obstruc- grade needle in the pelvis during the procedure tion requires a multidisciplinary approach, and allows the pelvicalyceal system to be reopacified prior consultation with the urologist and or and distended should decompression occur at any nephrologist is advisable. The nephrologist can fre- time. 330 PERCUTANEOUS NEPHROSTOMY—Maher et al.

The anatomy at the renal hilum is fundamental ployed. Alternatively, if there is marked hydro- to the performance of antegrade pyelography. It nephrosis, ultrasound can be performed prior to must be remembered that the renal vein, artery, puncture and the site can be marked. The needle and ureter run anterior to posterior in this order at can then be inserted without the necessity for real- the renal hilum. In addition, the colon can occa- time ultrasound guidance. In the case of a mildly or sionally be found posterior to the kidney, which can moderately obstructed kidney, real-time ultrasound result in colonic injury during PCN. Ultrasound ex- guidance is necessary. amination prior to needle puncture is helpful in de- Most centers use either a 20- or 22-gauge nee- termining whether the colon is posterior to the kid- dle. Our preference, however, is for the 20-gauge ney. CT has been advocated either prior to PCN or needle because it is a little stiffer, and this is advan- as the guidance modality for PCN in order to avoid tageous for traversing the muscles and perinephric organ damage (Fig. 1), particularly when anatomic tissues more easily. The use of a 22-gauge needle for variations such as retrorenal colon, retrorenal liver crossing these quite rigid structures can result in or spleen, absent 12th rib, and low position of the some bending of the needle. The needle is passed pleural space make complications during PCN to the desired depth and is then withdrawn while as- more likely.6 However, in practice, these entities are pirating with a 10 mL syringe containing 2 mL rare, and we predominantly use ultrasound. saline. Once urine is aspirated from the needle, the Ultrasound guidance is employed to visualize needle hub is connected to an extension tube and either the renal pelvis or a calyx for direct punc- contrast material is injected. In patients with severe ture. It is our experience that the renal pelvis is a hydronephrosis, it can be difficult to achieve satis- more accessible target for direct puncture than a factory opacification with contrast material, and more peripherally based calyxis. Ultrasound is usu- withdrawing urine and replacing it with contrast ally employed for direct puncture but in some in- material is often necessary to achieve the degree of stances a needle can be guided into the renal pelvis pelvicalyceal opacification necessary to facilitate using fluoroscopic guidance. Using the fluoro- pelvicalyceal access. Once the contrast material is scopic technique the needle is directed using care- injected into the pelvicalyceal system, the fluo- fully chosen landmarks. The position chosen for roscopy table is tilted, leaving the patient in a puncture is usually approximately 2 to 3 cm lateral semierect position, which allows contrast to gravi- to the transverse process of the second lumbar ver- tate into the lower end of the ureter. This maneuvre tebra. When using ultrasound to direct the course is often vital in the determination of the cause and of the needle, a freehand technique is usually em- level of ureteric obstruction. Downloaded by: University of Florida. Copyrighted material.

Figure 1. CT scan showing the colon (arrow) posterior to the kidney. This a rare occurrence and CT is not war- ranted prior to PCN. However, ultrasound should be performed to out rule this rare eventuality. 331 SEMINARS IN INTERVENTIONAL RADIOLOGY VOLUME 17, NUMBER 4 2000

PELVICALYCEAL ACCESS At this stage some operators turn the patient into the prone oblique position, which at least in Once the pelvicalyceal system is outlined with theory makes the angle from the calyces into the in- contrast material, a calyx is chosen for puncture. fundibulum and renal pelvis a little less steep and The calyx chosen usually depends on the anatomic easier to negotiate. It is our practice to leave the pa- position of the kidney in relation to the ribs. tient in the prone position because we find that Usually the lower pole calyx is the most accessible there is little or no difficulty in passing a guidewire and is chosen for puncture. However, this choice from a posterior calyx into the renal pelvis. A single can be influenced by the possibility of further inter- stick needle access system (Neff, Cook Inc., Bloom- vention such as antegrade ureteral stent insertion. ington, IN, or Acustick, Meditech Inc., Watertown, If antegrade stent insertion is likely, then a midpole MA) is used to gain access into the chosen calyx. calyx is preferable to the customary lower pole ca- This system consists of a 22-gauge 15-cm needle, a lyx. Once the decision is made as to whether a mid- 0.018-inch guidewire, a metal cannula, a 4 Fr plastic pole or lower pole calyx puncture is to be used, it is cannula and a 5 Fr sheath (Fig. 2). important to decide whether the visualized calyces The skin position is marked using fluoroscopy are in an anterior or posterior plane. This can be 2 cm lateral to the chosen calyx. The skin is infil- decided by injecting either carbon dioxide or air trated with local anesthetic, an incision is made into the pelvicalyceal system using the needle em- with a No. 11 scalpel, and the 22-gauge needle is in- ployed for antegrade pyelography. It is usual to use serted under fluoroscopic guidance into the calyx 10 to 15 cc of air for this purpose. Prior to the injec- chosen. A 10-cc syringe with 2 cc of saline is at- tion of any air, it is vital to ensure that the needle is tached to the hub of the needle, the stylet is re- definitely within the pelvicalyceal system and not in moved, and the needle is slowly withdrawn until the renal vein or artery to avoid potentially fatal air urine or air bubbles appear in the syringe. At this

embolism. The advantage of air or CO2 is that, once point, the 0.018-inch guidewire is passed through instilled, the gas rises into the posterior calyces in the needle into the calyx and is guided fluoroscopi- the prone position, thereby aiding the identifica- cally into the renal pelvis. On occasion, it can be dif- tion of the posterior calyces. ficult to advance the guidewire from the tip of the Downloaded by: University of Florida. Copyrighted material.

Figure 2. Percutaneous access set used for PCN (Neff, Cook, Bloomington, IN). The set consists of (A) a 15- cm, 22-gauge needle, (B) a 5 French plastic sheath with both an inner plastic stiffening canuala and an inner metal stiffening cannula, and (C) a 0.018-inch guidewire. The sheath assembly is designed to go over the 0.018-inch guidewire into the kidney so that a working wire such as a 0.036-inch guidewire can be placed. 332 PERCUTANEOUS NEPHROSTOMY—Maher et al. needle even through urine can be aspirated catheter that is used to provide catheter strength through the needle. This can usually be explained for the purpose of advancement. This is important by the fact that the needle tip is up against the wall to aid passage through the subcutaneous tissues, of the calyx. This problem can usually be overcome muscle, and perirenal tissues on the way to the re- by withdrawing the needle slightly and advancing nal pelvicalyceal system. Once the catheter has en- the 0.018-inch guidewire while turning the needle tered the kidney, it is important to withdraw the tip in various directions to aid the passage of the metal stiffening cannula and to slide the catheter guidewire into the renal pelvis. Once the guidewire over the guidewire. If one fails to do this, there is a is in the renal pelvis, the needle is removed, ensur- potential for kinking the guidewire or fracturing it ing the guidewire remains in an optimum position. or losing access. Depending on the size of the pelvi- The 5 Fr sheath assembly is placed over the guide- calyceal system, the nephrostomy tube is either wire into the pelvicalyceal system. It is important to placed in the upper pole calyx, coiled in the pelvis, detach the metal stiffening cannula when the or placed down the ureter. sheath system has entered the calyx. The metal can- To fix the catheter, a string at the hub of the nula is too stiff to traverse the angle between the ca- catheter is pulled to secure and lock the pigtail. lyx and the renal pelvis. Once the metal cannula is Depending on the catheter chosen, there are vari- withdrawn, the 5 Fr sheath and inner plastic can- ous ways of locking the pigtail. nula are flexible enough to follow the guidewire into the renal pelvis. If the metal cannula is left in place, attempts to force the sheath into the renal AFTERCARE pelvis will result in guidewire kinking in the calyx, and further pushing may cause the guidewire to slip Catheter fixation to the skin is important and out of the kidney altogether or may cause the can be accomplished in a number of ways. We use a guidewire to fracture. Once the 5 Fr sheath is in the Holister ostomy disk that can be placed on the pa- renal pelvis, the central stylet is removed and a tient’s skin with the catheter threaded through the 0.038-inch “J” guidewire is inserted through the opening in the center of the disk. Adhesive tape is 5 Fr sheath and either coiled in the renal pelvis, placed around the catheter and the adhesive tape is placed into the upper pole calyx, or manipulated then sutured to the ostomy disk. Alternatively, adhe- down the ureter (Fig. 3). sive tape, which is first placed around the catheter, can be sutured directly to the patient’s skin. In the absence of significant bleeding or clot PLACING THE NEPHROSTOMY formation, it is usually not necessary to irrigate a CATHETER nephrostomy catheter. Urine contains proteolytic enzymes that can break down any clot forming When the 0.038-inch “J” guidewire is securely within a catheter and keep the catheter patent. placed in the renal pelvis, the tract is dilated. Irrigation is usually necessary when pyonephrosis

Preference for guidewires used during nephros- is encountered or if there is considerable hemor- Downloaded by: University of Florida. Copyrighted material. tomy varies between operators. We consider the “J” rhage or clot formation during the procedure. guidewire adequate in most instances. Some opera- tors use 0.038-inch ring Lunderquist (Cook, Bloom- ington, IN) guidewires, and other operators use a RESULTS super stiff amplatz guidewire. If an 8 Fr nephros- tomy catheter is employed, the tract is dilated with The success rate for PCN approaches 100% in 8 Fr and 10 Fr dilators. If a 10 Fr catheter is being experienced hands. However, failure to access the placed, the percutaneous tract is dilated with 8, 10, renal pelvicalyceal system has been reported to be and 12 Fr dilators, and so on. In most instances, an as high as 8%.6 The major difficulty encountered is 8 Fr nephrostomy catheter is adequate. However, when the system is not obstructed or dilated. In this where frank pus is encountered, a larger (10 or situation, antegrade pyelography is very helpful be- 12 Fr) catheter should be employed. It is vital at all cause it can allow distension of the system prior to times to observe the position and shape of the needle puncture. With PCN, the complication rate guidewire during dilatation because kinking or dis- has been reported to be approximately 4%, with a placement of the guidewire is possible during di- mortality rate of less than 0.2%.1–3 Hemorrhage latation of the tract. When the tract is dilated, the (Fig. 4) and infection are the two most frequent nephrostomy catheter (Cook, Bloomington, IN, or complications following PCN. A little hematuria is Meditech, Watertown, MA) is placed over the usually encountered following a standard PCN, but guidewire and into the renal pelvis. The nephros- severe bleeding with resultant hypotension usually tomy catheters usually come with a metal stiffening results from arterial damage and can be due to 333 SEMINARS IN INTERVENTIONAL RADIOLOGY VOLUME 17, NUMBER 4 2000

A B

C D Figure 3. Nephrostomy catheter placement in a patient with a blocked ureteric stent. (A) An antegrade needle (curved arrow) is first placed into the renal pelvis to outline the collecting system. A midpole calyx was chosen for ac- cess with a 22-gauge needle. Once urine was aspirated, a 0.018-inch guidewire (straight arrows) was coiled in the Downloaded by: University of Florida. Copyrighted material. renal pelvis. (B) The sheath assembly was placed over the wire into the collecting system after first withdrawing the metal stiffening cannula when the sheath assembly reached the renal cortex. The metal stiffening cannula will not negotiate the curve at the renal cortex, and attempts to force the sheath assembly without withdrawing the metal stiffening cannula will result in kinking of the guidewire. A 0.035-inch guidewire was placed and the sheath removed. (C) Percutaneous track dilatation with 8 and 10 French dilators. A 10 French dilator (arrows) can be seen dilating the track into the kidney. (D) Finally, an 8 French nephrostomy catheter is placed and the pigtail formed in the renal pelvis.

pseudoaneurysm or arteriovenous fistula forma- adequate preprocedure work-up and correction of tion. If there is significant bleeding through the any detected coagulopathies prior to the proce- catheter with associated hemodynamic instability or dure. Technically, the incidence of hemorrhage can a drop in the patient’s hematocrit, a renal an- be reduced by employing a more peripheral ap- giogram should be arranged with a view to em- proach to the calyces and avoiding direct puncture bolization of any identified bleeding sites. Overall, of the renal pelvis. however, hemorrhagic complications are rare. The other major complication is sepsis. The Delayed major hemorrhage is rare and is frequently generally accepted rate for sepsis has been reported due to rupture of a PCN-associated false aneurysm, to be between 1.4 and 4.5%,2,13–15 but higher rates but this is more common with the larger tracts used of up to 21% have been reported.4 Many patients for PCNL.11 In many ways, the most vital step in are septic prior to the procedure, and this proce- avoiding hemorrhage following this procedure is dure has the potential to aggravate this problem. 334 PERCUTANEOUS NEPHROSTOMY—Maher et al.

Figure 4. Retroperitoneal hemorrhage occurring after PCN. The patient became hypotensive on the return to the ward after a nephrostomy was performed. A CT scan showed a large amount of hemorrhage around the kidney. The nephrostomy catheter (arrow) can be seen entering the skin at this level. Note the malfunctioning kidney on the opposite side. The patient recovered with fluid resuscitation and did not require any other intervention. No specific reason was found for the hemorrhage, and the patient was not coagulopathic.

During PCN, there is potential for entry of bacteria ter (Cook, Bloomington, IN) to probe the tract. and endotoxins from an infected pelvicalyceal sys- Once the pelvicalyceal system has been entered, it is tem into the systemic circulation, which can result usually possible to place a new nephrostomy cathe- in profound endotoxic shock. In the septic patient, ter without difficulty. If pelvicalyceal access is not however, this can often be difficult to avoid. Two im- possible, a new nephrostomy catheter will have to Downloaded by: University of Florida. Copyrighted material. portant steps are mandatory. First, prophylactic an- be placed. Catheter occlusion is also a complication tibiotics should be administered routinely prior to that is infrequently encountered. Initial endeavours all nephrostomy procedures where there is a risk of should include attempting to unblock the catheter sepsis. Second, the operator must avoid overdisten- using saline flushes. It may also be possible to open sion of the renal pelvicalyceal system during ante- the existing catheter by using a guidewire. If this is grade pyelography because this can precipitate not possible, the catheter can be exchanged by us- pyelorenal backflow of infected urine with resultant ing a 9 Fr peel-away sheath. The hub of the catheter endotoxic shock.12 is cut and the 9 Fr peel-away sheath is inserted over Catheter-related problems such as dislodge- the catheter into the collecting system. The cathe- ment and occlusion frequently occur. Dislodge- ter is then removed, and a new catheter is inserted ment rates were reported as greater than 10% prior into the pelvicalyceal system. Using this method to the development of pigtail catheters, but this de- there is no need for the use of a guidewire. velopment has reduced the incidence of this com- plication. In the event of catheter dislodgement, the patient should be returned to the interven- SPECIAL CIRCUMSTANCES tional suite as soon as possible. If the nephrostomy tube has been in situ for a considerable amount of TRANSPLANT KIDNEY time it may be possible to replace the catheter Urinary tract obstruction following renal trans- through the nephrostomy tract. We usually employ plantation can occur in the immediate postopera- an angled guidewire (Terumo) and a Kumpe cathe- tive period, when the cause of obstruction is usually 335 SEMINARS IN INTERVENTIONAL RADIOLOGY VOLUME 17, NUMBER 4 2000

edema at the ureterovesical junction. PCN may be can be chosen for access; however, if future ureteric necessary in these cases to preserve function in the stenting is contemplated, a midpole or upper pole newly transplanted kidney. The placement of a calyx is the preferred choice. Following this, a nephrostomy tube in these cases is of a temporary 0.018-inch guidewire is inserted through the needle nature. A much less common cause of obstruction for the purposes of subsequent access into the pelvi- in the transplant kidney is ureteric torsion or calyceal system. Once the guidewire is in satisfac- ureteric stricture, which commonly occur because tory position, the procedure follows the description of ischemia. Other indications would include described for nephrostomy in the native kidney. It is ureteric leak or anastomotic breakdown in the post- usually easier to dilate the percutaneous tract in the operative period. Placing a PCN is usually much transplant kidney than it is in the native kidney be- easier in the transplant kidney compared with the cause of the superficial position of the transplant native kidney. This is because the transplant kidney kidney compared with the native kidney, which is is usually superficially placed in the right or left usually at a much greater distance from the skin. An flank. When performing PCN in the transplant kid- 8 Fr nephrostomy tube is usually satisfactory, and ney (Fig. 5), only a single needle puncture is neces- once the 0.018-inch guidewire is in satisfactory posi- sary both for the antegrade pyelography and for tion, the procedure follows the description of later access to the pelvicalyceal system. The needle nephrostomy in the normal kidney. is passed under ultrasound guidance. We frequently employ a Micropuncture Introducer Set (William RETROGRADE NEPHROSTOMY Cook, Europe A/S, Bjaeveskov) to gain initial ac- VIA AN ILEAL LOOP cess. Alternatively, a 22-gauge needle is employed Patients with an ileal conduit who present with and is passed into a calyx. An antegrade pyelogram an obstructive uropathy pose a difficult problem. In is performed and the system is distended. Any calyx this clinical scenario, a retrograde approach to the Downloaded by: University of Florida. Copyrighted material.

A B

Figure 5. PCN in a transplant kidney. This pa- tient had rising serum creatinine levels and previous surgery for an ischemic transplant ureter. (A) A Tenchkoff catheter (straight arrows) is seen in situ. An ultrasound had shown that the upper pole calyx was the most dilated. This was punctured with a 22- gauge needle (curved arrow). (B) The 5 French sheath assembly was placed over the 0.018-inch wire into the upper pole calyx and a 0.035-inch wire (arrow) coiled in the upper pole calyx. (C) An 8 French nephrostomy catheter was then placed into C the upper pole calyx after appropriate track dilatation. 336 PERCUTANEOUS NEPHROSTOMY—Maher et al. ileal conduit is worth considering for nephrostomy NONDILATED COLLECTING SYSTEM drainage. Obstruction in these patients is usually due to recurrent tumor or a stricture at the anasto- Percutaneous nephrostomy is at its most diffi- mosis between the ureter and ileal loop. It is our cult when it is performed on a nondilated collect- practice to perform a contrast loopogram prior to ing system. The most common clinical situation in any intervention to confirm that there is no reflux which PCN is required for treatment of a nondi- of contrast medium from the ileal loop into the lated collecting system is postoperative ureteric ureter. Following this, the presence or absence of leaks. PCN or stent placement, or both, is the pre- obstruction can be confirmed. It is important also ferred treatment. However, access to the collecting to note that if there is a recurrent bulky tumor system is usually difficult because the collecting sys- within the ileal loop it is most appropriate to per- tem is decompressed through the site of ureteric in- form the nephrostomy drainage via an antegrade jury. On ultrasound, the collecting system is usually approach. decompressed and ultrasound guidance is not usu- The ileal loop is cannulated with a Kumpe ally helpful. It is our practice in this clinical situa- catheter and a straight 0.035-inch hydrophyllic tion to give 50 to 75 cc of a 300 mg/mL nonionic guidewire (Terumo). The Kumpe catheter and contrast material to opacify the pelvicalyceal sys- guidewire are manipulated to the end of the ileal tem. Once satisfactory opacification has been loop. When the catheter has reached the end of the achieved, an antegrade needle is inserted into the ileal loop, the guidewire is removed and exchanged renal pelvis under fluoroscopic guidance. Once for a 0.038-inch super stiff or extra stiff wire. A 9 Fr the needle is in satisfactory position, it is employed peel away sheath is placed over the super stiff to achieve optimal distension of the pelvicalyceal guidewire. The 9 Fr peel away sheath will usually system. reach the end of the ileal loop. This is the key step At this point an accessible calyx usually in the in retrograde procedures. The 9 Fr peel away lower or middle pole is chosen for nephrostomy ac- sheath straightens out any tortuosity of the ileal cess. Many of these patients will have antegrade loop. In addition, it protects the guidewire and stents placed, and therefore midpole calyces are Kumpe catheter from peristalsis, which may cause preferable. A 22-gauge needle is placed into the the guidewire and catheter to be extruded from the midpole calyces and a 0.018-inch guidewire is ma- ileal loop. The Kumpe catheter is again placed over nipulated into the renal pelvis. It is vital to ensure the super stiff wire, and the super stiff wire is ex- that the pelvicalyceal system remains distended by changed for a hydrophyllic guidewire. The ureteric trying to maintain a steady injection of dilute con- orifice is then searched for using the Kumpe trast material into the pelvicalyceal system using the catheter and guidewire. It is useful to inject contrast antegrade needle. It is significantly easier to pass a because a small jet can often be seen at the ureteric 0.018-inch guidewire into the renal pelvis when it is orifice. It is our practice to review all previous intra- distended. Once access is gained, the procedure venous urograms or loopograms because these fre- can be performed in the traditional fashion. quently can aid in choosing the most appropriate Downloaded by: University of Florida. Copyrighted material. place to search for the ureteric orifice. Once the ureteric orifice is traversed with the CT-GUIDED NEPHROSTOMY DRAINAGE guidewire, the Kumpe catheter is manipulated up the ureter and into the kidney. The guidewire is Rarely, CT guidance is necessary to gain access then removed and a 0.035-inch super stiff or extra to the kidney. CT-guided drainage is usually re- stiff guidewire placed up into the kidney. An 8 Fr quired for those patients who have severe kyphosco- nephrostomy catheter can be placed or, if the dis- liosis. In these patients, severe kyphoscoliosis makes tance is longer either internal or internal and ex- the assessment of the relationship of the kidney to ternal, ureteral stents can be placed (Fig. 6). other vital structures very difficult (Fig. 7). The Whichever catheter is placed, it is important to colon can be a particular problem in these patients. leave the distal end of the catheter in the patient’s In addition, obstructive kidneys in severely kypho- ostomy bag and not in the ileal loop. If the distal scoliotic patients are difficult to identify with ultra- end of the catheter is left in the ileal loop, it will sound, and even in the presence of a satisfactory an- tend to clog rapidly. This is because the ileal loop tegrade pyelogram, the pelvicalyceal system can still sheds dead cells on a regular basis, and the catheter be difficult to identify and to access. The patient is side holes will tend to become clogged with silt. If it placed prone on the CT table and a noncontrast CT is not possible to negotiate the ureteric orifice, the through the kidneys is performed. Under CT guid- patient can be turned prone and an antegrade ance, a 22-gauge needle can be placed either into nephrostomy can be performed. the renal pelvis as an antegrade needle for opacify- 337 SEMINARS IN INTERVENTIONAL RADIOLOGY VOLUME 17, NUMBER 4 2000

A B

Figure 6. Retrograde nephrostomy in a patient with recur- rent transitional cell carcinoma in an ileal loop. (A) CT scan shows a mass (arrows) consistent with recurrent transitional cell cancer in the ilea conduit. (B) A loopgram shows the stenosis (arrow) cased by the recurrent tumor. (C) Rather than placing bilateral nephros- tomy catheters, the loop was catheterized retrogradely and a 10- French nephrostomy cather (arrows) placed proximally in the loop C to provide drainage for both kidneys. Downloaded by: University of Florida. Copyrighted material.

A B

Figure 7. Patient with a severe kyphoscoliosis in whom CT guidance was used for nephrostomy catheter placement. (A) CT guidance was performed to place the 22-gauge needle into the renal collecting system. The pa- tient was then transferred to fluoroscopy. (B) An 8-French nephrostomy catheter was placed under fluoroscopy with- out difficulty. CT guidance was useful to exclude any intervening organs between the skin and the kidney. 338 PERCUTANEOUS NEPHROSTOMY—Maher et al. ing the pelvicalyceal system or directly in the calyx an outpatient procedure. Gray et al5 found that 6% of choice. The patient is then transferred to the flu- of patients were readmitted as a direct consequence oroscopy room for fluoroscopic guidance during of PCN, 2% each because of sepsis, bleeding, and the placement of guidewires and catheters. The ma- difficulty in managing the PCN tube. Overall it was jor advantage of CT compared with other methods possible to avoid hospitalization in 82% of patients. of image guidance for the performance of PCN is Gray concluded that PCN could be performed that the anatomic relationship of the kidney to safely in selected patients but that patients with co- other vital structures can be clearly evaluated. As a agulation disorders, signs of urinary tract sepsis, result of this, potentially disastrous damage to these staghorn calculi, and hypertension should be organs can be avoided in a way that is not possible treated as inpatients. Overall, it is still our practice with fluoroscopy or ultrasound. to admit patients for PCN because most patients Recent studies have appeared in the literature who require PCN in our institution are ill. that have documented and evaluated the use of CT in the performance of PCN. 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