Protective factors in posterior urethral valves.

Patients with posterior urethral valves may present with or contract renal insufficiency. High intravesical pressure that is transmitted to the upper urinary tract in utero is a likely contributing cause. We have identified 3 anatomical associations with posterior urethral valves that provide a pressure "pop-off" mechanism resulting in preservation of better renal function: 1) the syndrome of posterior urethral valves, unilateral vesicoureteral reflux and renal dysplasia; 2) large congenital type bladder diverticula and 3) urinary extravasation with or without urinary ascites. Followup of 71 boys with posterior urethral valves was sufficient to permit long-term analysis. Serum creatinine was used as an index of renal function and prognosis. Of the 71 boys 20 (28 per cent) had 1 of the 3 protective mechanisms. Only 1 child (5 per cent) had a serum creatinine greater than 1.0 mg. per cent. Of the remaining 51 boys without a "pop-off" mechanism 20 (39 per cent) had serum creatinine greater than 1.0 mg. per cent and 7 had already progressed to renal dialysis and/or transplantation. The difference in serum creatinine was statistically significant (p less than 0.01). Thus, the syndrome of posterior urethral valves, unilateral vesicoureteral reflux and renal dysplasia; large congenital bladder diverticula and urinary extravasation can serve as a "pop-off" mechanism to buffer high pressures in the urinary tract and to lead to the preservation of better renal function in boys with posterior urethral valves.

Ureteroscopic diagnosis and treatment of urinary calculi during pregnancy.

Flexible ureteroscopy has been utilized in two pregnant patients. In one, the procedure was for diagnosis of symptoms simulating ureteral colic, and in the other for the removal of a distal ureteral calculus. The diagnostic procedure was completed with local anesthesia alone, and both procedures were performed without radiation to the mother or fetus. The potentially great benefit must be weighed against the risks of minimal endoscopic intervention in each patient. We advocate the early but judicious use of flexible ureteroscopy in pregnant patients with urinary calculi.

Ureteropyeloscopic removal of ureteral calculi.

Ureteroscopy has been used for the treatment of calculi throughout the ureter. The results of ureteroscopic stone removal were reviewed in 100 patients. Similar results were compared in 30 patients undergoing ureterolithotomy and 32 treated by basket manipulation. Success of ureteroscopic removal was related to the location of the calculus: 50 per cent in the proximal, 80 per cent in the mid and 99 per cent in the distal ureter. Hospital stay, costs and narcotic analgesic use were significantly less for ureteroscopic stone removal than for open surgical lithotomy. The success rate for ureteroscopic removal of distal calculi (99 per cent) was higher than for blind basketing procedures (59 per cent). Ureteroscopy should be considered the technique of choice for the removal of distal ureteral calculi. It is an acceptable alternative for treatment of calculi throughout the urinary tract.

Ureteroscopy under local anesthesia.

Ureteroscopy has been performed with local anesthesia with and without sedation in 30 patients. Flexible endoscopes were used in 18, rigid endoscopes alone in 7, and rigid and flexible instruments in 5 patients. The flexible instruments ranged in size from 4F to 10F, while rigid instruments were 10F to 12F. Although most procedures were diagnostic, calculi were removed from the distal ureter in 4 patients and from the midureter in 1 patient. Ultrasonic lithotripsy was utilized in 1 patient. The success and tolerance of flexible or distal rigid ureteroscopy with local anesthesia permits its recommendation in carefully selected patients.

Intrarenal dimensions. Guidelines for flexible ureteropyeloscopes.

Designs for flexible ureteropyeloscopes should be based on the configuration of the intrarenal collecting system. This study measured retrospectively the ureteroinfundibular angle and infundibular lengths of 30 patients treated for calculus disease. Recommendations are given for the design of flexible ureteropyeloscopes that could visualize the entire normal intrarenal collecting system.

Percutaneous antegrade flexible ureteroscopy.

A flexible endoscope has been used for antegrade percutaneous ureteroscopy after percutaneous lithotripsy. The instrument, the ACMI Flexiscope, is 2.5 mm in diameter and has fiberoptic bundles for illumination and visualization but no channel for irrigation. Techniques for introduction and irrigation are considered. The use of this instrument demonstrates the need for deflectability in a ureteroscope.

Pain control: comparison of percutaneous and operative nephrolithotomy.

Percutaneous removal of renal calculi is an effective form of therapy with less morbidity than some other operative procedures. The narcotic requirements of 21 patients treated percutaneously were compared with a comparable group of patients treated by open nephrolithotomy. Patients treated percutaneously stayed in the hospital for 8.9 days and required 6.5 doses of narcotics. Patients treated by open surgical lithotomy remained in the hospital for 11.0 days and required 21 doses of narcotics. When compared on a daily basis, patients in the open operative group required 2.7 times more doses of narcotics than patients treated percutaneously. Percutaneous nephrolithotomy appears to be significantly less painful than operative nephrolithotomy utilizing a standard flank incision as indicated by narcotic analgesic usage.