Ureteroscopic decompression of an unusual uroepithelial cyst using the holmium:YAG laser.

We report a case of an unusual uroepithelial cyst arising from a renal calix in an African-American man with sickle cell trait. The lesion was incised and decompressed using a 7.5F flexible ureteroscope in conjunction with the holmium:YAG laser and a 200-microm quartz laser fiber. To our knowledge, endourologic management of this type of lesion has not been described in the literature.

Identifying stone composition using infrared analysis of filtered urine after ureteroscopic lithotripsy.

BACKGROUND AND PURPOSE: With the development of small-caliber ureteroscopes and lithotripsy devices, it is now possible to perform intracorporeal stone fragmentation without dilatation of the ureteral orifice. Ureteral stones are typically fragmented into small particles that can be difficult to retrieve for stone analysis. Infrared spectroscopy (IRS) of the precipitate from urine after intracorporeal lithotripsy represents a method for obtaining stone analysis. PATIENTS AND METHODS: A total of 69 patients underwent ureteroscopic lithotripsy with the holmium laser or the electrohydraulic probe for stones in the ureter (N = 65) or kidney (N = 4). Each patient's bladder was then drained and the urine filtered. The resulting precipitate was analyzed using IRS. RESULTS: The amount of material for analysis was < or =1 mg in 56 patients (82%). Stone composition was positively identified in 44 patients (64%). Material suitable for analysis was recovered from 73% of patients when the bladder was drained with a cystoscope sheath compared with 43% when a urethral catheter was used (P = 0.03). There was no significant difference in pretreatment stone size in the patients who had a positive v a negative result (11.7 mm v 10.9 mm; P = 0.06). Similarly, the stone location was not significantly related to the likelihood of positive analysis (P = 0.29). CONCLUSION: Straining the urine after ureteroscopic intracorporeal lithotripsy and analyzing the precipitate with IRS is able to identify stone composition in the majority of patients. This method is especially useful in the setting of holmium laser lithotripsy, in which the majority of the stone is converted to spontaneously passable particles.

Holmium:YAG lithotripsy in children.

PURPOSE: We determined the safety and efficacy of holmium:YAG lithotripsy in children. MATERIALS AND METHODS: We retrospectively reviewed the records of all holmium:YAG lithotripsy done in patients 17 years old or younger. Demographic, preoperative, intraoperative and postoperative data were collected. RESULTS: A total of 9 boys and 10 girls (26 stones) with a mean age of 11 years (range 1 to 17) were treated with holmium:YAG lithotripsy, which was chosen as initial therapy in 10 (53%). Retrograde ureteroscopy was performed in 15 patients to treat 13 ureteral and 6 renal calculi, and percutaneous nephrolithotripsy was done in 4 to treat 3 ureteral and 4 renal calculi. A complete stone-free outcome after 1 procedure was achieved in 16 children (84%) and 3 patients were rendered stone-free after 2 procedures. No patient had an intraoperative injury. Followup ranged from 0.5 to 12 months (mean 3). Followup imaging has shown no evidence of stricture or hydronephrosis. CONCLUSIONS: Holmium:YAG lithotripsy is safe and effective in children. It is a reasonable option for failed shock wave lithotripsy, or in children with a known durile stone composition or contraindications to shock wave lithotripsy.

Percutaneous suprapubic cystolithotripsy for treatment of large bladder calculi.

BACKGROUND AND PURPOSE: The treatment options available for managing bladder calculi include transurethral cystolithotripsy, open cystolithotomy, and shockwave lithotripsy. For larger calculi, transurethral treatment can be time consuming, and the manipulation has the potential to cause urethral injury. Percutaneous suprapubic cystolithotripsy represents another treatment option for bladder calculi which is effective and minimally invasive. PATIENTS AND METHODS: Fifteen patients had bladder calculi treated with percutaneous cystolithotripsy over a 3-year period. The mean stone size was 39 mm (range 10-64 mm). Stones were single in seven patients and multiple in eight patients. The indications for cystolithotripsy were stone size >3 cm, multiple stones >1 cm, and inability to perform transurethral cystolithotripsy because of patient anatomy. Percutaneous suprapubic cystolithotripsy was done through either a 30F or a 36F cystotomy tract. Fragmentation and removal was performed with a 26F rigid nephroscope and the pneumatic Swiss Lithoclast. Suprapubic and urethral catheters were placed postoperatively in all patients. RESULTS: Each patient was cleared of the stone burden with a single procedure, and there were no major complications. The mean duration of suprapubic catheterization was 2.6 (range 1-5) days. CONCLUSION: Percutaneous suprapubic cystolithotripsy is an effective and safe technique for treating large bladder calculi. It is minimally invasive, avoids urethral injury, and, in combination with the pneumatic Swiss Lithoclast, can be used to fragment and remove large and hard bladder calculi.

Secondary ureteroscopy: results and management strategy at a referral center.

PURPOSE: In an era when extracorporeal shock wave lithotripsy occupies a dominant place in the treatment of urolithiasis ureteroscopy retains an important role in certain circumstances. While often a definitive procedure, ureteroscopy can be associated with potential risks and complications. The treatment of patients who have undergone a failed attempt at ureteroscopic stone retrieval or have a complication may be complex. As a tertiary care stone referral center we review our experience with performing salvage ureteroscopy following a previous unsuccessful attempt at endoscopic stone removal. MATERIALS AND METHODS: Between May 1990 and February 1996, 79 patients were referred following an unsuccessful attempt at retrograde endoscopic or basket manipulation for ureteral calculi. A retrospective review of the outcomes of these patients was conducted. Of the patients 11 presented with associated complications, which included ureteral perforation (4), intramural false passage (1) and fever or sepsis (6). Complications were managed by early establishment of urinary tract drainage by stenting or nephrostomy. Among patients without complications elective salvage ureteroscopy was performed. RESULTS: Ureteroscopy was used in 79 patients with a successful outcome (stone-free) in 75 (95%). Followup imaging with renal ultrasound or excretory urography at least 3 months after secondary ureteroscopy was available in 65 patients and showed no evidence of hydronephrosis or delayed stricture formation. CONCLUSIONS: Treating the patient who undergoes a failed attempt at ureteroscopy may be problematic and requires access to a wide array of endourological equipment. Each subsequent treatment should be individualized with consideration given to stone size, location and general health. In the presence of a ureteral injury establishment of early urinary tract drainage is essential. Following stabilization, secondary ureteroscopy can be performed yielding high stone-free rates with minimal complications.

Evaluation of Doppler ultrasonography and dynamic contrast-enhanced CT in acute and chronic renal obstruction.

The development of a reliable, minimally invasive method of distinguishing physiologically significant renal obstruction from dilation without obstruction would have important clinical implications. As it is well known that renal blood flow decreases over time in the presence of obstruction, we investigated the ability of color flow Doppler ultrasonography and dynamic contrast-enhanced CT scanning to detect changes in blood flow in unilaterally obstructed porcine kidneys. In the initial phase of this study, the effect of acute unilateral obstruction were studied in nine pigs. The resistive index (RI) was measured with Doppler ultrasonography, and renal blood flow was quantitated with dynamic CT using tracer kinetic principles and deconvolution. The RI measurements were unable to distinguish between the obstructed kidneys and their controls. Dynamic CT scanning demonstrated a greater fall in blood flow in the obstructed kidney, and this change was significantly different from baseline. The same findings were supported by radiolabelled microsphere blood-flow measurement. In the chronic portion of the study, after surgical creation of a partial ureteric obstruction, the kidneys were studied by both techniques at 1, 2, and 3 weeks. Again, RI was unable to demonstrate any difference between obstructed and unobstructed kidneys, while CT showed a progressive fall in blood flow in each successive week that was statistically significant. Dynamic contrast-enhanced CT scanning is a promising diagnostic tool that might be used to distinguish a functionally significant renal obstruction from nonobstructive dilation. Further clinical studies to validate this technique are warranted.

Holmium:YAG laser endoureterotomy for treatment of ureteral stricture.

OBJECTIVES: Endourologic techniques ranging from balloon dilation to endoincision with electrocautery, cold knife, and lasers have been increasingly used in recent years for the treatment of ureteral strictures. While the long-term results may not be as reliable or as durable as traditional reconstructive surgical techniques, they can be accomplished with much less morbidity. Recently, the holmium:yttrium-aluminum-garnet (YAG) laser, which possesses both cutting and coagulating properties, has been demonstrated to have many applications in urology. We report our experience with this laser in the endoscopic treatment of ureteral strictures. METHODS: We reviewed the charts and follow-up history of 22 patients in whom the holmium:YAG laser was used to treat ureteral strictures from a variety of causes and including those in ureteroenteric anastomoses. Strictures were either approached in a retrograde fashion with a 6.9F ureteroscope or antegrade with flexible instruments in the cases involving ureteroenteric strictures. The only energy source employed was the laser, followed by balloon dilation. Indwelling stents were left in place for at least 4 weeks postoperatively and follow-up was obtained with radiographic imaging. RESULTS: A minimum 9-month follow-up was available for 18 patients. There were 5 patients who had developed recurrent strictures and were therefore considered treatment failures. Each of these patients failed in less than 3 months and all had either lengthy or complex strictures noted at the time of surgery. One patient was lost to follow-up and three recent patients have follow-up of 3 to 6 months showing no evidence of recurrent stricture formation. Overall, 16 of 21 (76%) patients are clinically well with no evidence of stricture recurrence. CONCLUSIONS: Endoureterotomy for ureteral stricture disease is a minimally invasive, less morbid, but ultimately less successful, alternative to open surgical reconstruction. Stricture length and etiology remain the most important determinants of success. The holmium:YAG laser, with its ability to precisely cut tissue and provide hemostasis and its multiuse potential and compatibility with small rigid and flexible endoscopic instruments, is an ideal tool for performing endoureterotomy.

Management of vesical calculi: comparison of lithotripsy devices.

Although endoscopic lithotripsy of bladder stones has been well described and is widely practiced, comparison of the main modalities of mechanical, electrohydraulic, and ultrasonic lithotripsy is lacking. The exact role of these and other modalities such as the Swiss Lithoclast and extracorporeal shockwave lithotripsy is not clearly defined. The safety and efficacy of the various lithotripsy modalities available to treat bladder calculi were reviewed retrospectively over an 18-year period. A total of 106 patients were treated with some form of intracorporeal lithotripsy. In general, all devices proved to be effective with a low rate of complications. The addition of transurethral resection of the prostate to bladder stone management under the same anesthetic was also found to be a safe procedure for moderate benign prostatic hyperplasia. In summary, transurethral endoscopic lithotripsy is a safe and effective method of bladder stone management both alone and in combination with transurethral prostatectomy. All modalities of intracorporeal lithotripsy are effective; however, devices such as ultrasound lithotripters or the Swiss Lithoclast that utilize larger, rigid probes may be more efficient for patients with large or particularly hard vesical calculi.

Intracorporeal lithotripsy with the holmium:YAG laser.

PURPOSE: Preliminary evaluations of the holmium:YAG laser have demonstrated a variety of potential urological applications, including ablation of soft tissue lesions as well as stone fragmentation. We present our experience with the holmium:YAG laser for intracorporeal lithotripsy of urinary calculi. MATERIALS AND METHODS: During a 24-month period 75 patients underwent 79 laser procedures, including retrograde ureteroscopy for ureteral calculi (71) and fragmentation of caliceal stones remote from the nephrostomy tract during percutaneous nephrolithotripsy (8). RESULTS: Complete stone fragmentation without need for additional procedures or lithotripsy was achieved in 85% of the cases. Treatment failures included 1 case of stone migration, 7 incomplete fragmentation requiring other lithotripsy devices and 3 laser malfunction. One ureteral perforation occurred when the laser was activated without direct visual guidance. CONCLUSIONS: The holmium:YAG laser has demonstrated its efficacy as a method of intracorporeal lithotripsy. Advantages include ability to fragment stones of all composition, and the multipurpose, multispecialty applications of the holmium wavelength. This laser has potential soft tissue effects, and careful attention to technique during lithotripsy is required to avoid ureteral wall injury.

Oliguria during laparoscopic surgery: evidence for direct renal parenchymal compression as an etiologic factor.

Abdominal insufflation during laparoscopy has been associated with transient oliguria, which abates after desufflation. Direct renal compression evoking a Page kidney effect was proposed as a mechanism. In an effort to confirm this theory, the left kidney was subjected to 15 mm Hg compression in six anesthetized mongrel dogs. For this, a pressure cuff was placed around the kidney excluding the renal hilar structures. The contralateral kidney was left untouched to serve as a control. After a steady-state period, the pressure cuff was inflated to 15 mm Hg for 2 hours. Cuff desufflation was followed by a 1-hour recovery period. Urine output, glomerular filtration rate (GFR), and effective renal blood flow (ERBF) were measured for both kidneys during each clearance period. For the treated kidneys, the mean urine output decreased 63% (P < 0.05) during compression and increased 109% (P < 0.05) after cuff desufflation. The GFR decreased 21% (P < 0.01) during compression and increased 25% (P < 0.05) during recovery. The ERBF decreased 26% (P < 0.05) during compression, and during the 1-hour recovery period, ERBF did not recover to baseline values. For the control kidneys, there were no significant changes in urine output or GFR during the experimental and recovery periods. These data support the view that direct renal parenchymal compression is an important factor in the development of insufflation-induced oliguria. The clinical implications of insufflation-induced oliguria during laparoscopy deserve further investigation.

Alteration of laser-tissue interaction with the 805 nm diode laser using indocyanine green in the canine prostate.

BACKGROUND AND OBJECTIVE: Research interests in laser prostatectomy continue to evaluate a variety of wavelengths and treatment parameters in an effort to optimize treatment. Recently, a semiconductor diode laser with a wavelength of 805 nm has become available for clinical use; however, free-beam noncontact applications were limited by the low power output (25 W). In this study in the canine prostate, the possible potentiating effects of intravenously administered indocyanine green (ICG) were evaluated with the 805 nm diode laser. STUDY DESIGN/MATERIALS AND METHODS: A total of 16 fixed position, free-beam lasings were performed at 25 W for 60 sec in four dogs with eight lasings before and eight lasings after ICG administration. Endoscopic observations and measurements of lesion volumes were used to evaluate the laser-tissue interactions. RESULTS: Prior to ICG administration, we observed that side fire irradiation produced primarily small coagulative lesions. Following ICG administration, however, immediate and more noticeable tissue vaporization occurred, although total lesion size was not increased. Pathologic review demonstrated less coagulation and hyperemia, but a larger vaporized cavity in the ICG treated tissue. CONCLUSION: These findings suggest intravenous ICG alters laser-tissue interaction with the 805 nm diode laser in the canine prostate. The use of the 805 nm diode laser with enhancing chromophores deserves further investigation.

Ureteral lithotripsy with the electromechanical impactor.

Electrohydraulic lithotripsy (EHL) of ureteral calculi has proved to be an effective and relatively inexpensive method of intracorporeal lithotripsy. However, the potential for significant ureteral injury is an everpresent concern with conventional EHL. The electromechanical impactor (EMI), an innovative modification of a standard EHL probe, has been shown in initial investigations to be capable of fragmenting urinary calculi with a greater margin of safety. Herein, we describe our preliminary experience with this new device in 23 patients with ureteral calculi. In nine patients selected to undergo EMI treatment, the device could not be employed because of either inability to access the stone with the large endoscope required (six cases) or device malfunction (three cases). Among the patients in whom the EMI was used, five required an additional modality of intracorporeal lithotripsy to complete stone fragmentation. In the remaining nine patients, stone fragmentation was achieved with the EMI as the sole modality of lithotripsy, for an overall success rate of 39% (9/23). There were no complications directly related to use of the EMI as noted endoscopically or on postoperative imaging. The EMI appears to be a safe device for intracorporeal lithotripsy. Its application to a large population of patients with ureteral stones may be limited by the probe size (5F), which precludes its use with the smaller rigid and flexible ureteroscopes.

Electrosurgical vaporization of the prostate in the canine model.

OBJECTIVES: To investigate the histopathologic changes and heating patterns caused by electrosurgical vaporization of the prostate in the living canine model. METHODS: Prostate electrosurgical vaporization was undertaken in the canine model. Temperatures within and near the prostate and of the irrigation fluid were measured during a single pass and during the creation of a vaporized cavity. The prostate and adjacent tissues were examined by gross and microscopic pathology. RESULTS: Coagulation occurred deep to the vaporization zone for 1.38 to 1.44 mm for a single pass of the rolling cylinder and up to 2.52 mm for multiple passes. Thermometry revealed temperature increases of only 4 degrees C 5 mm away from the vaporization site. The largest temperature increases were found in the irrigation fluid as it passed through the prostatic fossa. Microscopic pathology revealed no damage to adjacent tissues. CONCLUSIONS: Electrosurgical vaporization creates minimal deep heating and coagulation beyond the vaporized cavity. The majority of the heat is removed by the irrigation fluid.

Soft-tissue applications of the holmium:YAG laser in urology.

The holmium:YAG laser possesses both ablative and hemostatic properties and in preliminary clinical use has demonstrated many potential urologic applications. We review our initial experience in treating a variety of soft-tissue lesions of the urinary tract with this laser. A total of 51 patients underwent 53 procedures including superficial bladder tumor ablation (25), incision of ureteral stricture (15), incision of urethral stricture (6), relief of ureteropelvic junction obstruction (3), incision of bladder neck contracture (2), and ureteral tumor ablation (2). Procedures were considered successful, with no further intervention or alternative energy source required, in 81% of the cases. The laser demonstrated precise hemostatic cutting and warrants further investigation as a multipurpose urologic laser.

Preliminary experience with holmium: YAG laser lithotripsy.

Lithotripsy with the pulsed-dye laser has been shown to be a safe and effective method of intracorporeal urinary stone fragmentation. Recently, a new device, the holmium: YAG laser, has been developed with both soft tissue and lithotripsy applications. We present our preliminary experience with the Ho:YAG laser for lithotripsy of urinary calculi. Ureteroscopy and lasertripsy resulted in successful fragmentation of ureteral stones in 92% of 21 patients when the laser was used alone or in combination with electrohydraulic lithotripsy. One complication directly related to the use of the laser occurred, a ureteral perforation, when the device was utilized under fluoroscopic control. In four patients undergoing percutaneous flexible nephrolithotripsy, the laser demonstrated utility in fragmenting caliceal stones remote from the nephrostomy tract. In summary, the Ho:YAG laser has demonstrated its efficacy as a method of intracorporeal lithotripsy. The tissue effects of this device, as well as the optimal energy/pulse and frequency settings, need further evaluation in order to minimize the risks of tissue injury.

Investigation of the tissue effects of a new device for intracorporeal lithotripsy--the Swiss Lithoclast.

Currently three modalities are available for intracorporeal stone fragmentation--electrohydraulic, ultrasound and laser lithotripsy. A new device, the Swiss Lithoclast, has been developed by the Departments of Medical Electronics and Urology at the University of Lausanne, Switzerland. This device has been used clinically in several countries for the treatment of stones throughout the human urinary tract. While no adverse outcomes have been reported, the potential tissue effects of the device have not been thoroughly investigated in an animal model. The objective of the present study is to evaluate the possible acute and long-term tissue effects of this instrument on the pig urinary tract. In all acute animals, visible mucosal lesions were seen at the site of probe firing in the bladders and ureters. Histologic examination demonstrated the effects of acute trauma with edema, hemorrhage and mucosal denudation. No significant long-term tissue effects were noted either pathologically or on radiographs in the 3- and 6-week animals. This study confirms our clinical impression that the Swiss Lithoclast effectively fragments urinary calculi and is associated with a large margin of safety.

Laser prostatectomy with the holmium: YAG laser.

Laser prostatectomy has generated considerable interest amongst urologists as an alternative to traditional transurethral resection for the treatment of benign prostatic hypertrophy. The majority of reports available concerning laser prostatectomy have described use of the neodymium: YAG wavelength delivered via contact or non contact fibers. Recently, a new laser wavelength has become available for urologic use. The holmium: YAG laser is a multipurpose device with many potential applications in urology as well as other surgical disciplines. At a wavelength of 2,100 nm, this laser possesses both ablative and hemostatic properties. Energy and frequency settings can be varied by the operator. Using the holmium: YAG laser as well as the neodymium: YAG laser in a combined procedure, we performed laser prostatectomies in 16 patients. In our series we used the holmium laser to vaporize a channel prior to producing quadrant irradiations with the Nd:YAG laser. At 3-month follow-up there was a mean reduction of AUA symptom scores from 19 to 9 and a mean improvement in peak flows from 13.9 to 16.6 ml/s. Early results show clinical effect but the optimal technique of combined holmium: YAG, Nd:YAG laser prostatectomy is yet to be determined.

Endourologic management of seminal vesicle cyst.

Cystic lesions in the region of the seminal vesicles, ejaculatory ducts, or prostate are rare and can be a diagnostic and therapeutic challenge. Open surgery is often necessary for definitive treatment. Recent refinements in transrectal ultrasound imaging and endoscopic instrumentation have expanded the roles of these modalities in the management of retrovesical cysts. We present a case in which a semirigid 6.9F ureteroscope was used to access and drain a seminal vesicle cyst transurethrally, thereby obviating open surgery.

Endoscopic management of ureteral injury after cesarean section.

Ureteral injury is an uncommon complication of cesarean section. As with all iatrogenic ureteral injuries, if the problem is not recognized intraoperatively, the manifestations may be protean. The management of ureteral injury that is first recognized in the early postoperative period must be individualized. We present a case of ureteral injury during a cesarean section in which endoscopic techniques were employed successfully to establish kidney drainage and allow ureteral healing, obviating open surgical repair.

Fatal air embolism during radical retropubic prostatectomy.

Air embolism during urological surgery only rarely has been reported. We report a case of fatal air embolism occurring during radical retropubic prostatectomy. This entity is discussed in an attempt to raise the level of awareness of this rare but potentially lethal complication, especially in view of the ever increasing popularity of radical retropubic prostatectomy as the treatment for organ confined carcinoma of the prostate.