In what is to our knowledge the largest series of stone analysis reported to date we identified an age and gender relationship of stone formation and composition. Regional variations are common and underline the influence of living habits, diet and standard of medical care on urinary stone formation.

Penile insensitivity is a symptom commonly observed after traumatic or iatrogenic nerve lesions, or in association with neurological or vascular diseases. In contrast, we report 2 cases of intermittent genital hypesthesia that occurred in cyclists after long-term bicycle riding. Anatomical studies show that this condition was probably caused by an irritation of the pudendal nerve during its course through the Alcock canal as reported in the literature. No pathological findings were demonstrated on extensive physical examinations, medical history and all medical imagings (sonography of abdomen, prostate and testes, and magnetic resonance imaging of the pelvis and lumbar spine) as well as radiodiagnostics and Doppler sonography, nor was there evidence of other neurological disturbances. The symptoms in the 2 patients spontaneously resolved after 4 and 7 weeks, respectively, without specific medical therapy.

Between 1978 and 1988 5,035 urinary calculi have been analysed by X-ray diffractometry. 1,615 of these stones have additionally been investigated by scanning electron microscopy (SEM). The overall sex-ratio was 1.86 (m/f). Ca-stones and uric acid containing stones are more frequent in male patients (m/f = 2.08 and 3.86, respectively) whereas infection stones and cystine stones show a higher rate of appearance in female patients (m/f = 0.6 and 0.88, respectively). The percentage of open surgery ranged about 30% in the first few years but decreased to 5-7% in the last few years due to the new methods of stone removal. The rate of occurrence of the crystalline phases does not differ remarkably from other statistics except for a higher incidence of apatite because of the high sensitivity of detection of this phase by SEM. The recurrence rate of brushite stones amounting to 66.7% is very high and exceeds even that of cystine stones (60.7%).

Texture and micro-morphology of 1615 urinary calculi has been studied using scanning electron microscopy and X-ray micro analysis. Together with the results of X-ray diffractometry concerning their phase composition, a classification into five stone classes, 13 stone groups and 17 sub-groups could be evaluated. Especially the large and inhomogeneous class of the calcium-stones could be resolved into 13 stone types. Using this classification, the stone type is characterized by a three digit number containing the stone class, the stone group and in some cases the sub-group. Criteria for classification are typical texture patterns, the occurrence of special crystalline phases or both. These items are presented and clinical relationships discussed.

During the last ten years, data of urinary calculi was received in 4094 cases on the criterion of "recurrence", whereby the answer was "yes" in 1446 cases. The overall "adjusted relative recurrence rate" (ARRR) is therefore 35.3%. The importance of an exact physical analysis of urinary stones, involving a differentiation of the various Ca oxalates and Ca phosphates, becomes clear looking at the high recurrence rates for the monomineralic stones of the Ca stone class like brushite and weddellite (ARRR = 66.7% and 50.0%, respectively) compared to apatite and whewellite (ARRR = 36.5% and 29.2%, respectively). Dramatic changes in the composition of the recurrent stone were observed only in 12.7% of all cases. The highest ARRR was found in infection stones with a large content of struvite (about 75%), whereas the total recurrence rate of the infection stone class was about 38%. An assessment of the "danger" of a urinary stone taking into account the criteria of "composition" and "prevalence to recur" is given.