Laparoscopic nephrectomy: looking back, moving forward

This manuscript reviews the history of laparoscopic nephrectomy and addresses the future trends of this minimally invasive operation.

Imaging and focal therapy in prostate and kidney cancer

The advancement of imaging modalities in the past two decades has led to the increased incidence of small renal masses. This same technology is making nephron-sparing treatment of small renal masses much more feasible and precise. The goal of this manuscript is to review the currently available imaging modalities utilized in focal treatment and follow-up of small renal masses.

Lower pole I: a prospective randomized trial of extracorporeal shock wave lithotripsy and percutaneous nephrostolithotomy for lower pole nephrolithiasis-initial results

PURPOSE

The efficacy of shock wave lithotripsy and percutaneous stone removal for the treatment of symptomatic lower pole renal calculi was determined.

MATERIALS AND METHODS

A prospective randomized, multicenter clinical trial was performed comparing shock wave lithotripsy and percutaneous stone removal for symptomatic lower pole only renal calculi 30 mm. or less.

RESULTS

Of 128 patients enrolled in the study 60 with a mean stone size of 14.43 mm. were randomized to percutaneous stone removal (58 treated, 2 awaiting treatment) and 68 with a mean stone size of 14.03 mm. were randomized to shock wave lithotripsy (64 treated, 4 awaiting treatment). Followup at 3 months was available for 88% of treated patients. The 3-month postoperative stone-free rates overall were 95% for percutaneous removal versus 37% lithotripsy (p <0.001). Shock wave lithotripsy results varied inversely with stone burden while percutaneous stone-free rates were independent of stone burden. Stone clearance from the lower pole following shock wave lithotripsy was particularly problematic for calculi greater than 10 mm. in diameter with only 7 of 33 (21%) patients becoming stone-free. Re-treatment was necessary in 10 (16%) lithotripsy and 5 (9%) percutaneous cases. There were 9 treatment failures in the lithotripsy group and none in the percutaneous group. Ancillary treatment was necessary in 13% of lithotripsy and 2% percutaneous cases. Morbidity was low overall and did not differ significantly between the groups (percutaneous stone removal 22%, shock wave lithotripsy 11%, p =0.087). In the shock wave lithotripsy group there was no difference in lower pole anatomical measurements between kidneys in which complete stone clearance did or did not occur.

CONCLUSIONS

Stone clearance from the lower pole following shock wave lithotripsy is poor, especially for stones greater than 10 mm. in diameter. Calculi greater than 10 mm. in diameter are better managed initially with percutaneous removal due to its high degree of efficacy and acceptably low morbidity.

How do urology residents manage personal finances?

OBJECTIVES

To examine personal financial management among residents to answer three research questions: do residents make reasonable financial choices; why do some residents not save; and what steps can be taken to improve residents' personal financial decisions.

METHODS

Portions of the Federal Reserve Board's Survey of Consumer Finances were modified and piloted to elicit demographic, expense, saving, and income data. The final questionnaire was completed by 151 urology residents at 20 programs.

RESULTS

Comparing residents with the general population in the same age and income categories, the median debt/household income ratio was 2.38 versus 0.64. Residents had greater educational debt, greater noneducational debt, and lower savings. Resident participation in retirement accounts was 100% at institutions with employer-matching 401k or 403b plans, 63% at institutions with nonmatching 401k or 403b plans, and 48% at institutions without retirement plans for residents (P = 0.002). Fifty-nine percent of residents budgeted expenses, 27% had cash balances below $1000, 51% had paid interest charges on credit cards within the previous year, and 12% maintained unpaid credit card balances greater than $10,000. The median resident income was $38,400.

CONCLUSIONS

A significant minority of residents appear not to make reasonable financial choices. Some residents save little because of a failure to budget, indebtedness, high projected income growth, or insufficient attention to personal financial management. Residents save more when they are eligible for tax-deferred retirement plans, particularly when their institution matches their contributions. Many residents would benefit from instruction concerning prudent financial management.

MAG3-F0 scintigraphy in decision making for emergency intervention in renal colic after helical CT positive for a urolith

Patients with renal colic are evaluated with clinical, laboratory, and imaging methods for stratification for emergency decompression, medical treatment, or discharge and follow up. The current standard practice is heavily based on unenhanced helical CT for detecting uroliths. However, the presence of a urolith does not necessarily mean that the kidney is obstructed and requires emergency decompression. In this study, technetium-mercaptoacetyltriglycine (MAG3) diuretic scintirenography was used to detect obstruction in patients with renal colic. The contribution of this test to patient management after positive findings from helical CT was also studied.

METHODS

Diagnostic criteria were established on the basis of previous experience with 60 patients who had renal colic and had undergone radiography of the kidneys, ureters, and urinary bladder (KUB) and diuretic Tc-MAG3 scintirenography and were followed up to correlate scintigraphic findings with clinical outcome. Subsequently, 80 patients with renal colic underwent scintigraphy within 12 h of presentation in the emergency room, after abdominal helical CT showed findings positive for calculus and suggestive of obstruction. After therapeutic oral or intravenous hydration and analgesics, diuretic dynamic renal scintigraphy (flow, function, delayed imaging) was performed after intravenous injections of 10 mCi (370 MBq) 99mTc-MAG3 and 40 mg furosemide (at zero time, or F0). Results were available soon after completion of the study and were considered in patient management. Four characteristic patterns of scintirenography, essential in patient stratification and treatment, had been standardized and were used for interpretation of the studies: the unobstructed kidney; the partially obstructed kidney, proximally or distally obstructed, with mild to severe obstruction and impairment of function; the totally obstructed kidney, with arrested renal function; and the unobstructed but dysfunctioning kidney after decompression, or stunned kidney.

RESULTS

Among the 80 patients with positive helical CT findings, 56.5% were found to have obstruction by scintigraphy (32.5% partially, 24% completely); the remaining 43.5% did not have obstruction (21% without an indication of recent obstruction and 22.5% with stunned kidneys after spontaneous decompression). Occasionally, findings of preexistent urine extravasation or infection were present. Patients who, by scintigraphy, never had obstruction or had experienced spontaneous decompression did not require admission or emergency intervention; those with complete or severe obstruction required admission and decompression for relief of pain or restoration of function, whereas those with mild obstruction were treated variably with forced fluids, analgesics, or, less frequently, elective surgery. Outcome information from clinical examination, imaging, and interventional findings indicated that this stratification was successful. The test caused no side effects.

CONCLUSION

For renal colic, clinical selection, KUB radiography, and even positive helical CT findings were all found to have a low positive predictive value for obstruction (in this study, 35%, 32%, and 56% respectively). Anatomic studies, including helical CT, should be followed by diuretic MAG3-F0 scintirenography to diagnose and quantify or exclude obstruction, detect spontaneous decompression, and appropriately stratify patients for emergency intervention, observation and medical therapy, or further work-up and discharge with referral to the clinic.

A new tool to aid the urologist in the placement of stents for impacted ureteral stones or strictures: the glide catheter

We describe a technique one can use when only a lubricious wire is able to pass an impacted stone that could otherwise not be passed, over which a new hydrophilic "Glide Catheter is then passed beyond the stone. The lubricious wire can then be exchanged for a stiffer wire that will aid the retrograde passage of a ureteral catheter, stent, or other endourologic device in both a safe and effective manner.

Radiofrequency ablation of rabbit kidney using liquid electrode: acute and chronic observations

BACKGROUND AND PURPOSE

The percentage of small renal tumors being diagnosed has increased at least five-fold in the last 20 years. The question of how best to treat these lesions remains unanswered. We studied the effectiveness of "wet" radiofrequency (RF) ablation of renal tissue.

MATERIALS AND METHODS

New Zealand white rabbits (N = 48) underwent a 1- or 2-minute ablation of renal parenchyma with a modified insulated spinal needle capable of infusing saline, measuring temperature and impedance, and delivering RF energy. Animals were followed and examined up to 54 days after surgery.

RESULTS

All animals survived for the planned period. Intravenous urograms showed no fistula or urinoma formation and confirmed continued function of the remaining parenchyma. The 1-minute treatments consistently ablated 20% to 25% (average 7 cm) of the tissue, whereas the 2-minute treatments ablated 34% to 36% (average 10 cm). Acutely, there was coagulative necrosis and infiltration of inflammatory cells. Chronically, there were well-demarcated lesions with complete effacement of the tubular epithelium and destruction of the glomeruli.

CONCLUSION

Wet radiofrequency ablation with a liquid electrode can reproducibly create large lesions safely and quickly. The technique may soon become an alternative, minimally invasive therapy for small renal tumors.

A new self-expanding lined stent-graft in the dog ureter: radiological, gross, histopathological and scanning electron microscopic findings

Recurrent or intractable ureteral strictures pose a significant problem for the practicing urologist. Metallic stents have been used sparingly for this problem with varying success. We investigated the use of a stent-graft consisting of a metal stent lined with a porous biocompatible polymer to determine if the liner would prevent urothelial ingrowth. One ureter of each of 11 dogs was treated with either a metallic woven stent or stent-graft inserted retrograde via a midline cystotomy. Six bare wire stents (controls) and five lined with a new, porous, biocompatible, polycarbonate elastomer liner (Corethane) were placed. The animals were followed radiographically with intravenous urography (IVP) at 6 weeks and just prior to sacrifice (12 to 22 weeks). Gross, histological, and electron microscopic analyses were performed. The results demonstrate that all of the bare metal stented animals developed moderate to severe hydroureteronephrosis with significant urothelial hyperplasia and ingrowth through the spaces between the metal wires. The animals implanted with lined stents showed one instance of mild hydroureteronephrosis (observed radiographically but not grossly at time of sacrifice) and virtually no papillary in-growths of urothelium through the stent interstices. This obstructive phenomenon was prevented by the porous polymer lining. There was no evidence of biodegradation of the liner on scanning electron microscopy. Based upon these findings, the marriage of a biocompatible polymer which provokes minimal tissue reaction, and metallic stents which provide tremendous strength, seems to offer significant advantages when placed into the urinary tract to maintain ureteral luminal patency.

Ex vivo comparison of four lithotripters commonly used in the ureter: what does it take to perforate?

We hoped to determine the number of pulses and energy needed to create acute ureteral perforations with four different lithotripters in a reproducible ex vivo model. A simple model was constructed to control variables in the testing such as wall thickness, intraluminal pressure, distance between the probe tip and ureter, and power delivered to tissue. Segments of domestic pig ureter were prepared and fixed in position in a normal saline (NS) bath at room temperature. We then attempted perforation with the holmium:YAG (HoL) laser, coumarin pulsed-dye laser (CdL), electrohydraulic lithotripter (EHL), and pneumatic impactor (PI) by placing the instrument probes at right angles to the ureteral wall. The ureter was filled with a methylene blue-stained solution of NS at 90 cm H2O pressure via a urodynamics catheter, and perforation was recorded on initial extravasation of dye. The endpoints measured were time to perforation and total energy required. At 0.5 mm of separation between the wall and probe, the HoL perforated the ureter in an average of 2 seconds and 0.01 kJ delivered at 5 W (10 Hz and 0.5 J/pulse). The EHL perforated at an average of 24.44 +/- 8.77 seconds and a total energy of 0.01 +/- 0 kJ. The CdL was able to perforate but at much longer intervals (257.51 +/- 99.08 seconds) and higher energy levels (12.88 +/- 4.95 kJ) on average than either the EHL or HoL. Lastly, the PI was unable to perforate the ureter in more than 6 continuous minutes of application. In addition, we found that at 2-mm separation between the HoL probe tip and the ureteral wall, acute perforation was not possible even at very high power settings. We conclude that although each endoscopic lithotripter has advantages as well as disadvantages, in this ex vivo model, it was clear that the HoL and EHL can easily perforate the ureter and must be used with vigilance. It was found that at 2 mm of separation between the probe and target, the HoL, was unable to perforate acutely. The CdL and PI were associated with a much higher safety index, and the PI was unable to produce ureteral perforation.

Transurethral prostate ablation with saline electrode allows controlled production of larger lesions than conventional methods

A novel technique for prostate ablation using radiofrequency (RF) energy coupled to tissue with interstitial perfusion of saline solutions from a screw-tip catheter has been developed. The electrolyte spreads the current density away from the metal electrode and increases the effective electrode surface area, allowing more RF power input. This prevents tissue desiccation and impedance rise, resulting in controlled production of large lesions. In this study, we attempted to produce similar results using a straight needle and the saline electrode with a transurethral approach and compared the results with those of the same technique without electrolyte perfusion (conventional RF method). For this study, we designed an insulated 22-gauge needle with thermocouples embedded along its length and a 1-cm exposed tip with a retractable intraluminal thermocouple. This needle was inserted into the urethra of 10 dogs through a small perineal incision. Under transrectal ultrasound guidance, the exposed tip of the needle was placed in the center of each lobe. The intraluminal thermocouple was moved from the exposed tip up to the prostate capsule to monitor temperature. The highest power that could be applied in conventional RF methods without immediate desiccation was determined from preliminary experiments as 10 W. Subsequently, 10 W of RF power (475 kHZ) was delivered in one lobe until either the capsule temperature reached 48 degrees C or high impedance (> 400 omega) occurred. In the other lobe, 50 W of RF energy (475 kHz) and electrolyte perfusion (14.6% NaCl, 1 mL/min) were delivered until the capsule temperature reached 48 degrees C or high impedance occurred. Prostate lobe sizes ranged from 3.93 cm3 to 44.47 cm3 (mean 15.07 cm3). At 10 W without saline perfusion, high impedance from tissue desiccation occurred at 45 +/- 27 seconds, with lesions ranging from 0.06 cm3 to 0.93 cm3 (mean 0.34 cm3). At 50 W with saline perfusion, there was no tissue desiccation or impedance rise. The RF application time averaged 181 +/- 115 seconds until the capsule reached 48 degrees C, resulting in lesions ranging from 2.53 cm3 to 22.88 cm3 (mean 8.54 cm3). This study demonstrates that transurethral ablation of the prostate with a saline electrode allows controlled production of larger lesions than conventional RF methods. This may permit a single RF application in each lobe to produce lesions effective for the treatment of benign prostatic hyperplasia even in large glands.

Laparoscopic complications in markedly obese urologic patients (a multi-institutional review)

OBJECTIVES

Significant obesity is considered to be a relative contraindication to laparoscopic surgery. This study reviews the complications encountered in massively obese patients undergoing urologic laparoscopic surgery.

METHODS

Body mass index (BMI) was used as an objective index to indicate massive obesity. Eleven institutions compiled retrospective data on 125 patients having a BMI greater than 30. Procedures performed included 76 pelvic lymph node dissections, 14 nephrectomies, 7 bladder neck suspensions, and 28 miscellaneous procedures.

RESULTS

For the group as a whole, the mean BMI was 35.1 (range 30.1 to 57.2). Mean operative time was 202 minutes (range 60 to 480). Conversion to open surgery occurred in 15 of the 125 patients (12%). Complication rates (minor and major) were 22% (27 occurrences in 125 patients) intraoperatively and 26% (33 occurrences in 125 patients) postoperatively. The major complications included 2 trocar injuries to abdominal wall vessels, 1 bladder injury, 3 peripheral nerve injuries, 1 dysrhythmia, 1 deep vein thrombosis, 1 wound seroma, 1 nephrocutaneous fistula, 1 incisional hernia, and 1 death.

CONCLUSIONS

In this review, complication rates for urologic laparoscopic surgery on massively obese patients were higher than in the general population undergoing laparoscopic surgery (0.3% to 21%).

Enhanced radiofrequency ablation of canine prostate utilizing a liquid conductor: the virtual electrode

Conventional radiofrequency (RF) ablative techniques have shown promise for the treatment of symptomatic benign prostatic hyperplasia (BPH); however, present RF technology is limited by the small lesion size, necessitating several probe placements and heating cycles to achieve sizable lesions. This limitation is attributable primarily to a rapid increase in electrical impedance secondary to tissue desiccation and charring at the electrode tip. We devised a hollow screw-tip needle electrode that permits fixation to tissue, recording of temperature and impedance, infusion of fluid, and delivery of RF energy. Infusion of electrolyte solution (i.e., saline) into tissue prevents impedance rise by conducting RF energy away from the metal electrode and permits the creation of large lesions. By varying the conductivity of the perfusate (concentration and temperature), lesions of large diameter can be created in a controlled manner. To determine the long-term tissue effects, we applied this new modified RF technique to the prostates of five mongrel dogs in a chronic (0.5 to 8-week) study. The screw-tip electrode was serially embedded into each lobe of the perineally exposed glands with 1-minute infusion of 0.9% saline (2 mL/min) followed by application of RF energy (500 KHz, 50 W, 2-18 minutes) along with continuous saline infusion. Thermocouples were embedded 5 mm below and at the gland capsule, and RF application was discontinued when the temperature reached 50 degrees C at the periphery. Postoperatively, the animals were examined daily for clinical status and weekly for glandular changes using transrectal ultrasonography. At predetermined intervals, the animals were sacrificed and the prostates excised, measured, sectioned, and examined for histologic changes. Ablative tissue temperatures of 50 to 100 degrees C were produced while impedance remained stable. Four animals required a single catheterization for relief of urinary retention between days 2 and 3; otherwise, all animals demonstrated a quick and uneventful recovery with no edema detectable on day 7 ultrasound examination. The outside dimensions of the gland remained relatively constant throughout the study (+ or - 0.39 cm L + W + H). Histologic examination revealed coagulation necrosis (ablation) in both lobes of all prostates (69.94% + or - 16.62% of the gland) with tissueless cavities forming from the ablation area (28.71% + or - 8.24% of the gland) contained within the capsule surrounded by healthy tissue at the periphery. Intraprostatic lesions were obtained without any gross damage to surrounding tissue, including the bladder and rectal wall. Utilizing a liquid conductor in prostate tissue allows a single electrode-placement heating cycle for controlled ablation for the potential treatment of BPH. This new technique produces more extensive and uniform lesions than conventional RF procedures, and lesion size is limited only by the duration of RF energy application.

Laparoscopic unroofing of symptomatic renal cysts: three distinct surgical approaches

Although they are rarely associated with complaints, benign renal cysts may be the cause of pain, hypertension, or other problems. Simple aspiration is rarely definitive treatment. We have had good results with three laparoscopic approaches to cyst unroofing: transperitoneal, with reflection of the colon medially or dissection through the mesocolon and direct retroperitoneoscopy. We recommend initial percutaneous aspiration with cytology study both to rule out malignancy and to identify those cysts clearly in need of unroofing.

Laparoscopic unroofing of a renal cyst via a mesocolonic window: a different approach

We report a case of an elective laparoscopic transperitoneal removal of a large renal cyst by dividing the colonic mesentery without mobilizing the colon to gain access to the kidney. This appears to be a safe and potentially less costly approach compared to the standard flank approach of these simple renal cysts.

Stryker frame adaptation of the HM3 lithotriptor for treatment of distal ureteral calculi

Treatment of distal ureteral stones with the Dornier HM3 lithotriptor depends on the localization and positioning of the calculus from a transgluteal approach. We found the Stryker frame gantry modification preferable to the standard gantry for treatment of stones in the distal ureter. We report the use of this gantry adaptation in 22 cases of distal ureteral stones. The calculi were localized in 100% of the cases and were fragmented successfully with 1 treatment in 89%. In no case was the procedure aborted secondary to nonvisualization of the calculus. Failure to disintegrate the stone requiring retreatment occurred in 11% of the cases, and was attributed to stone characteristics and not due to difficulty with visualization or placement of the calculus within the F2 focus. The average fluoroscopic time was 45 seconds. The Stryker frame modification to the standard Dornier HM3 lithotriptor allows for improved visualization and easier localization of distal ureteral calculi compared to the standard gantry.

Laparoscopic common bile duct exploration

Operative common bile duct exploration, performed in conjunction with cholecystectomy, has been considered the treatment of choice for choledocholithiasis in the presence of an intact gallbladder. With the advent of laparoscopic cholecystectomy, the management of common bile duct stones has been affected. More emphasis is being placed on endoscopic sphincterotomy and options other than operative common duct exploration. Because of this increasing demand, we have developed a new technique for laparoscopic common bile duct exploration performed in the same operative setting as laparoscopic cholecystectomy. A series of five patients who successfully underwent common bile duct exploration, flexible choledochoscopy with stone extraction, and T-tube drainage, all using laparoscopic technique, is reported. Mean postoperative length of hospital stay was 4.6 days. Outpatient T-tube cholangiography was performed in all cases and revealed normal ductal anatomy with no retained stones. Follow-up ranged from 6 weeks to 4 months, and all patients were asymptomatic and had normal liver function tests.