Pneumatic v electrokinetic lithotripsy in treatment of ureteral stones.

Recently, a new device (Combilith) for electrokinetic lithotripsy (EKL) has become available which is very similar to the well-known device for pneumatic (ballistic) lithotripsy (Swiss Lithoclast). The Lithoclast uses air pressure to push a projectile within the handpiece against the end of a metal probe, which is thereby accelerated and thrown like a jackhammer against the stone. In principle, the same stroking movement of a small metal probe is provided by EKL; the difference is that instead of a projectile, a magnetic core within the handpiece is accelerated by the electromagnetic principle. This paper compares the clinical efficacy and the features of the two devices. Testing the devices on a stone model, taking into account stone propulsion, the systems turned out to equally effective regarding stone disintegration. However, stone displacement was more pronounced with the Lithoclast applied on easily breaking stones. In a second experiment, an optoelectronic movement-measuring apparatus (Zimmer camera) was employed to measure the range and velocity of the movement of the probe tip without any contact. The linear acceleration velocity ranged from 5 to a maximum of 12.5 m/sec with both systems, but the maximum height of the stroke was 2.5 mm with the Lithoclast and 1 mm with EKL. After the initial break-up of soft stones, further impact of the probe tip against the stone resulted merely in propulsion; thus, the greater probe stroke height is the cause of the stone displacement. In a clinical trial, 22 ureteral stones were treated with the Lithoclast and 35 with the EKL. The two devices were equally effective in terms of stone disintegration and safety margin. Fixation using a Dormia basket was necessary in 12 cases (8 Lithoclast, 4 EKL). Although a difference in probe stroke height was noted when comparing pneumatic and electrokinetic lithotripsy, there were no clinically significant differences in the efficacy of stone fragmentation or stone-free rates. At the current time, EKL is less costly.

Nitric oxide based influence of nitrates on micturition in patients with benign prostatic hyperplasia.

BACKGROUND: Nitric oxide (NO) is involved in the physiologic regulation of smooth muscle relaxation in the prostate. Organic nitrates act as NO donors. In this prospective open study we prove the influence of orally given nitrates on micturition. METHODS: Thirty-two patients underwent a urological medical check-up prior to starting nitrate medication for cardiovascular disease. We examined peak flow rates, residual urine, IPS-score, PSA level and prostate volume. Exact inclusion and exclusion criteria were defined. Fifteen patients suffered from obstructive symptoms, 17 patients reported no subjective micturition problems. Urological re-evaluation was performed two weeks and three months after nitrate medication. RESULTS: A significant improvement of peak urinary flow rates (+3.1 ml/s; p<0.05), IPS score and significant decrease of residual urine volume (-22 ml; p<0.05) were found in the symptomatic patients. No significant changes of micturition parameters were found in asymptomatic patients. PSA levels and prostate volumes did not change in either groups. CONCLUSIONS: Organic nitrates influence micturition parameters in patients with obstructive benign prostatic hyperplasia. This might be explained by the known mechanism of NO donation (smooth muscle relaxation) of nitrates. More functional controlled studies are necessary to describe the grade of influence of nitrates on the prostate. Concomitant oral medication with nitrates must be considered as a relevant bias factor on BPH in future clinical studies.

Nephrogenic adenoma of the bladder.

A nephrogenic adenoma of the bladder in a 4-year-old girl with a past history of urologic surgery for vesicorenal reflux is described. The multifocal tumor was treated by transurethral resection. Relapse occurred 15 months later and was again treated by transurethral resection. Pathological aspects, clinical features and therapeutic considerations of this proliferative lesion are reviewed and discussed.

Transcutaneous penile oxygen pressure during bicycling.

OBJECTIVE: To evaluate the blood supply to the penis during bicycling and thus determine whether the associated perineal compression might be responsible for some cases of impotence. SUBJECTS AND METHODS: The transcutaneous penile oxygen partial pressure (pO2 ) at the glans of the penis was measured in 25 healthy athletic men; pO2 is readily measured by noninvasive techniques currently widely used in the management of premature infants, and which have been shown to give pO2 levels that correlate with arterial pO2 levels. The measurements in the healthy subjects were taken in various positions, before, during and after bicycling. RESULTS: The mean (sd) pO2 of the glans when standing before cycling was 61.4 (7.2) mmHg; it decreased after 3 min of cycling to 19.4 (4. 7) mmHg. After 1 min of cycling in a standing position it increased significantly to 68 (7.6) mmHg; when cycling was continued in a seated position, after 3 min the pO2 fell to 18.4 (4.2) mmHg and there was a full return to normal pO2 values after a 10-min recovery period. CONCLUSION: The pO2 seems to correlate with the blood supply to the penis. The present results support the hypothesis that as the penile arteries are compressed against the pubic bone by the saddle during bicycling, the pO2 values decrease. Additionally, shifting from a seated to a standing position while cycling significantly improved the pO2 value of the penis and penile blood oxygenation was then even greater. Therefore, we suggest that cyclists change their body position frequently during cycling. Correcting the handlebars or the height of the saddle, tipping the nose of the saddle to produce a more horizontal, or even downward pointing position, and attention to the design of the saddle may be the only required precautions.