Transurethral Ultrasonic Uretero-Lithotripsy: A New Technique

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AN ANALYSIS OF BALLOON DILATION TO FACILITATE URETEROSCOPY.

POTENTIAL FOR DISASTER: UNRECOGNIZED SUBMUCOSAL INSTRUMENTATION. •Franklin L. Smith and Edward S. Lyon, Chicago IL. (Presentation lo be made by Dr. Smith) Endourologic surgery has replaced open surgery as the indicated means of treating many urologic conditions with less morbidity. Maximizing endourologic success requires an extra degree of sensitivity and patience, with an awareness of potential pitfalls. We wish to emphasize that submucosal Instrumentation, when unrecognized, can be a cause of failure and may lead lo a disastrous outcome after an attempted endourologic procedure. Submucosal dissection occurs during passage of an instrument (guldewire, whistle tip ureleral catheter, stone basket, stenl, ureteral dilating bougies, ureteroscopes etc.l through a lumen, usually of the ureter. It Is Initialed by mucosa! perforation followed by entry of the Instrument beneath the mucosa, dissecting between the mucosa and the muscle wall of the ureter as the Instrument Is passed further. The nuoroscoplc course of the Instrument falsely appears proper, seemingly demonstrating the expected location lntralumenally, Aproblem becomes apparent subsequently when the procedure cannot be accomplished as planned: the stone cannot be visualized or engaged, the tumor Is never seen or lhe kidney requiring stenl drainage remains obstructed. In more severe cases the Involved ureteral segment may eventually slough. Treatment of the condition requires awareness and early recognition of the subtle signs of submucosal dissection. When resistance Is encountered during passage of an Instrument avoid applying force as the normal ureter should be negotiable with gentle maneuvering. The instrument should be replaced with a catheter for Injection and contrast used to delineate the normal lumen and lo rule out submucosal or extraureteral extravasation. A soft noppy tipped guldewire with a gentle angle can be used to negotiate a tortuous or slenotlc segment. When submucosal dissection obscures the true lumen, the safest course may be to back off, since subsequent ureteral damage may result. The elective endoscopic case may be reattempted after sevi,ral weeks. When emergent relief of obstruction Is required, percutaneous nephrostomy may be performed. A thorough understanding of the process of submucosal dissection is crucial to minimize complication and maximize success In virtually all endourologlc procedures. Through illustrative material the importance of submucosal dissection will be emphasized.

J.L. Huffman,* San Diego, CA and Demetrius Bagley, Philadelphia, PA. (Presentation to be made by Dr. Huffman) Balloon dilating catheters have been employed successfully to treat vascular narrowings by percutaneous translurninal angioplasty techniques. In addition, the catheters have had many urological applications including dilation of percutaneous nephrostomy tracts, dilation of ureteral strictures, and dilation of the ureteral orifice for ureteroscopy. In an effort to define the methodology, safety and efficacy of balloon dilation for ureteroscopy, patients were evaluated according to the pressure needed for dilation, the effectiveness of the dilation, and complications encountered. Eighty consecutive patients were studied who were undergoing ureteroscopy for calculus removal (50), diagnosis (20), or upper tract strictures (10). Dilation was performed cystoscopically using balloon dilating catheters. All patients had a guidewire passed cystoscopically over which the balloon dilating catheter was placed. Inflation was then performed slowly while measuring the pressure needed on a gauge. Fluoroscopy was also used to judge effectiveness of dilation and to ensure proper position of the balloon dilating catheter. All patients except three (4%) had successful dilation that enabled ureteroscopy to be performed. These three patients required dilation using metal bougies. Fifty percent of patients required more than 6 atmospheres of pressure but less than 12 atmospheres. Only 5% of patients required pressures greater than 12 atmospheres. There were no cases of perforation noted following dilation as judged by direct visual view or by radiographic contrast injection. Balloon dilation appears to be a safe and effective method to provide access into the upper tract for ureteroscopy. Important features of the technique include the use of catheters designed specifically for balloon dilation, the use of a pre-placed guidewire, slow balloon inflation with a pressure gauge, and the use of fluoroscopy.

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SAFETY AND EFFICACY OF ELECTROHYDRAULIC LITHOTRIPSY (EHL) IN THE TREATMENT OF URETERAL CALCULI. Max K. Willscher,

TnANSURETHRAL ULTRASONIC URETERO-LITHGrRIPSY I A NE:11 TECHNIQUE. Christian G. Chaussy and Gerhard J. Fuchs*, Los Angeles, Ca; Robert I. Kahn, San Francisco, Ca; Patrick T. Hunter*, Orlando, Fla; Roger Goodfriend, Los Gatos, Ca. (Presentation to be made by Dr, Kahn) This is a multi-center study to evaluate a new technique for transurethral ultrasonic uretero-lithotripsy, METHOD I Ureteroscopy is performed in the usual manner with a l~ureteroscope, This technique is different because the ultrasonic probe, which is advanced by a trlgger, is only 2,5 Fr, and is designed to vibrate in a transverse manner causing disintegration rather than drilling of the stone, It is therefore not necessary to apply force against the stone to cause fragmentation and thusly a stone basket is not required to fix the stone.Fragmentation usually occurs within 60 seconds of ultrasound time. Stone particles pass spontaneously or may be basketed. Because of the modality of the ultrasound, the side of the probe can be employed to pin the stone against the ureter to break up remaining fragments. A stent may be left in place, RESULTS:118 cases have been performed with a success rate of 97%,. Complications have been minimal and no open surgeries were performed. Heat production is negligible. Videotapes show this method yields 10 times more power, CONCLUSIONS1Because of the smaller size of the ureteroscope and the modality of the ultrasound, transurethral ultrasonic uretero-lithotripsy has been greatly improved. This technique may well be the method of choice for upper ureteral stones, especially when they are not candidates for extra corporeal shock wave lithotripsy. It is also the method of choice for lower stones which cannot be basketed, It is less invasive than percutaneous methods. Perforation has not been a problem as it has been with electrohydraulic shock wave lithotripsy when used in the ureter. It has been very useful in removing retained ureteral stone fragments in those cases requiring additional instrumentation following E.S.W,L., including 11 steinstrasse. 11

James F. Conway, Jr., Manchester, NH, Richard K. Babayan and Grannum Sant, Boston, MA and Paul Morrisseau, Burling-

ton VT.

(Presentation to be made by Dr. Babayan)

In order to assess the safety and efficacy of electro-

hydraulic lithotripsy (EHL) in the treatment of ureteral calculi, 31 cases from five institutions were reviewed retrospectively. All stones were greater than 8mm in size, with the largest measuring 21 x 11mm. Six stones were

located in the upper third ureter, 3 stones in the rnidureter, and 22 stones in the lower third ureter,

patients ranged in age from 20-62 years.

The

Access to the

stones was gained via rigid ureteroscopy in 29 cases,

while the flexible nephroscope passed through a percutaneous nephrostomy tract was used for 2 upper ureteral stones. EHL was performed using either the Wolf or ACMI unit, in

the single pulse mode, using the 5-French electrohydraulic probe under direct visualization. All but one calculus were composed of calcium oxalate, the latter beingstruvite. All stones were successfuly fragmented and retrieved with no residual calculi. The procedure was complicated by ureteral perforation·and extravasation of urine in 2 patients. Both were successfully managed by postoperative stenting. Open exploration was not required and no long term complications have been evident.

EHL offers safe and rapid stone fragmentation within the ureter when performed under direct visualization in the

single pulse mode. Probes can be passed through the smallest available ureteroscope (9.SF) with minimal ureteral dilatation. Ureteral injury is rare and can be adequately managed endoscopically. In our experience, EHL in the ureter appears to be equal in safety and superior in

efficacy to ultrasonic lithotripsy.

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