John D. Denstedt

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.

Electrohydraulic Lithotripsy of Renal and Ureteral Calculi

Electrohydraulic lithotripsy was used to manage 45 upper tract calculi (23 renal and 22 ureteral stones) in 40 patients. Electrohydraulic lithotripsy successfully fragmented 91% of the calculi. All ureteral fragments cleared; in 2 patients with renal calculi solitary 4 mm. stone fragments remained. There were no intraoperative or long-term complications directly related to the use of electrohydraulic lithotripsy in the upper urinary tract. We conclude that intrarenal and intraureteral electrohydraulic lithotripsy is a safe, effective, inexpensive means to perform intracorporeal lithotripsy.

Endoureterotomy for Treatment of Ureteral Strictures

Advances in endosurgical technology have provided the urological surgeon with an alternative to open surgery for the treatment of ureteral strictures. We report the use of an endoscopic intraureteral incision (endoureterotomy) followed by balloon calibration to treat benign ureteral strictures in 13 patients. With an average subjective and objective followup among successful endoureterotomies of 20 months (all cases 12 months or greater), the overall success rate for this procedure is 62%. Of these patients 5 also received triamcinolone injections into the stricture bed following incision and dilation. This method appeared to influence favorably subsequent ureteral patency. The only operative complication was a urinoma, which resolved without intervention. Endoureterotomy appears to be a safe and reasonably effective modality for the treatment of ureteral stricture disease.

Comparison of Endoscopic and Radiological Residual Fragment Rate following Percutaneous Nephrolithotripsy

The stone-free rate after extracorporeal shock wave lithotripsy (ESWL) is primarily determined by a plain abdominal radiograph alone. However, the accuracy of that assessment can be challenged by renal tomography and flexible nephroscopy. We report on 29 patients with large renal calculi treated with a combination of percutaneous nephrolithotripsy and ESWL. Stone-free rates were determined by plain abdominal radiograph, renal tomography and flexible nephroscopy. The plain abdominal radiograph and renal tomography overestimated stone-free rates by 35% and 17%, respectively, compared to flexible nephroscopy. To determine stone-free rates after ESWL renal tomography is superior to a plain abdominal radiograph alone. Also, among patients with large renal calculi the use of the flexible nephroscope markedly improves the stone-free rate.

Safety and Efficacy of Holmium: Yag Laser Lithotripsy in Patients With Bleeding Diatheses

Purpose: We assessed the safety and efficacy of ureteroscopy and holmium:YAG laser lithotripsy for treating upper urinary tract calculi in patients with known and uncorrected bleeding diathesis.Materials and Methods: We retrospectively reviewed the charts at 2 tertiary stone centers to identify patients with known bleeding diathesis who were treated with holmium:YAG laser lithotripsy for upper urinary tract calculi. A total of 25 patients (29 upper urinary tract calculi) underwent ureteroscopic holmium laser lithotripsy. Bleeding diathesis involved warfarin administration for various conditions in 17 patients, liver dysfunction in 3, thrombocytopenia in 4 and von Willebrand’s disease in 1. The mean international normalized ratio, platelet count and bleeding time were 2.3, 50 × 109/l. and greater than 16 minutes in patients on warfarin and in those with liver dysfunction, thrombocytopenia and von Willebrand’s disease, respectively.Results: Overall the stone-free rate was 96% (27 of 28 cases) and 29 of 30 p...

A comparison of renal damage induced by varying modes of shock wave generation

To evaluate for the possible differences in the extent of pathologic injury occurring following treatment with various lithotripsy modalities, we subjected rabbits to treatment on either an electrohydraulic, electromechanical, or piezoelectric lithotripter. Functional evaluations by enzymuria failed to reveal any difference in the extent of damage between the lithotripters. Pathologic evaluation of the kidneys revealed that both electrohydraulic and electromechanical lithotripsy resulted in an increased instance of acute subcapsular hematoma and fibrosis when compared to piezoelectric treated kidneys (p less than 0.001). Despite the definitive differences noted in the acute animals, there was no significant variation in the area of permanent renal damage that occurred between the various lithotripters.

The use of triclosan eluting stents effectively reduces ureteral stent symptoms: a prospective randomized trial.

Study Type – Therapy (RCT)

Potential application of polyisobutylene-polystyrene and a Lactobacillus protein to reduce the risk of device-associated urinary tract infections

Urinary tract infections (UTI) associated with prostheses continue to cause significant morbidity despite the development and implementation of new biomaterials and device coatings. Ureteral stents, placed to improve drainage of the kidney can become a nidus for infection and potentially serious kidney damage, through attachment of pathogens and biofilm formation. The present study investigated two approaches to reducing the risk of ureteral stent infection. The first involved comparing the resistance to bacterial attachment of medical grade silicone rubber, the current gold standard biomaterial for urinary tract devices, to that of polyisobutylene-polystyrene block copolymer (PIB-PS), a polymer with proven biomaterial potential but as yet untested within the urinary tract. The second approach studied the capacity of a recombinant protein (p29) originally isolated from Lactobacillus fermentum RC-14 to inhibit bacterial attachment when used as a device coating. The protein coat was successfully identified by atomic force microscopy (AFM), gel electrophoresis and surface enhanced laser desorption/ionization (SELDI) protein chip analysis and shown to be present for at least 96 h. The coating and the PIB-PS surface alone were found to significantly reduce the attachment of two common uropathogenic species, Escherichia coli 67 and Enterococcus faecalis 1131 in vitro in the presence of phosphate buffered saline alone. However, the effect was negated following additional urine coating of the sections prior to challenge, likely due to p29 desorption and the development of a urinary conditioning film. These findings highlight the complexity of translating in vitro data to the in vivo setting and the critical role urinary constituents play in the development of urinary tract device-associated infections.

Randomized controlled, multicentre clinical trial comparing a dual-probe ultrasonic lithotrite with a single-probe lithotrite for percutaneous nephrolithotomy

Study Type – Therapy (case series)

Urinary Calculi in Aviation Pilots: What is the Best Therapeutic Approach?

PURPOSE We reviewed treatment outcomes in a series of aviation pilots treated in the era of modern surgical techniques and provide recommendations regarding treatment in this unique group. MATERIALS AND METHODS We retrospectively analyzed the records of all aviation pilots surgically treated for urinary calculi at our 4 tertiary stone centers from January 1988 to June 2000. Preoperative data and postoperative results were evaluated. Primary outcome measures included stone-free status after initial therapy, time lost from work and overall stone-free rates. Secondary outcome measures included the need for secondary procedures and complications. RESULTS Of the 36 patients 17 had renal and 19 had ureteral stones. In 4 patients the stones passed spontaneously, while 17 were initially treated with extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Marietta, Georgia), 9 were initially treated with ureteroscopy and 6 were treated with percutaneous nephrolithotripsy. There was 1 complication. The stone-free rate for ESWL, percutaneous nephrolithotripsy and ureteroscopy after initial therapy was 35%, 100% and 100%, respectively. All patients were rendered stone-free after secondary therapy. Mean time lost from work for ESWL, percutaneous nephrolithotripsy and ureteroscopy was 4.7, 2.6 and 1.6 weeks, respectively. CONCLUSIONS Aviation pilots with surgical urolithiasis are best treated with an initial endoscopic procedure. Stone-free rates can be maximized, while time lost from work can be minimized when an endoscopic approach is used initially. All pilots with urolithiasis should undergo mandatory metabolic evaluations to institute medical therapy when indicated.