[Extracorporeal lithofragmentation and of direct contact. Development of mathematical models for calculating the energy and predicting the fragmentation]. / Litofragmentación extracorpórea y de contacto directo. Desarrollo de modelos matemáticos para el cálculo de la energía y la predicción de la fragmentación.

The present experimental 'in vitro' study pursues the development of mathematical equations which, prior to lithofragmentation, would allow to estimate the amount of energy required and to predict the degree of fragmentation for each of the different sources of energy. A total of 114 calculi with 6 different compositions were analyzed by conventional X-rays (Rx), computerized axial tomography (CT) and dual X-ray densitometry (DO). Calculi were then fragmented using 4 different types of energy: electrohydraulic (LEH), piezoelectric (LEP), ultrasounds (US) and pulse laser (LAS). The correlation between imaging techniques parameters on the one side, and the amount of energy used and degree of fragmentation obtained on the other one, allow with a multiple linear regression analysis, both to develop mathematical equations to estimate the amount of energy required, and to predict the fragmentation rate.

[Comparative analysis of lithiasic fragmentation induced by extracorporeal and direct contact sources]. / Análisis comparativo de la fragmentación litiásica inducida por las fuentes extracorpóreas y de contacto directo.

An in vitro experimental study on stone fragmentation was conducted on 114 calculi analyzed by infrared spectrophotometry. Four energy sources were utilized: electrohydraulic, piezoelectric, ultrasound and pulsed laser. We analyzed stone susceptibility to fragmentation (particles < 3 mm), pulverization (particles < 1 mm) and stone fragility (amount of energy/mg of calculus fragmented into particles < 3 mm) for each type of energy source of each of the following 6 stone compositions: calcium oxalate monohydrate, calcium oxalate dihydrate, magnesium ammonium phosphate, phosphate carbonate, uric acid and phosphate oxalate. The calcium oxalate dihydrate calculi were the most susceptible to fragmentation and the infective calculi (magnesium ammonium phosphate and phosphate carbonate) were the most susceptible to pulverization. The piezoelectric energy showed the highest capacity for fragmentation and pulverization of calculi. Stone fragility depended on each stone type and the energy source utilized.

[Efficacy and limitations of piezoelectric extracorporeal lithotripsy in kidneys with anatomical abnormalities]. / Eficacia y limitaciones de la litofragmentación extracorpórea piezoeléctrica (LEP) en riñones con anaomalías anatómicas.

We analyze the results achieved by extracorporeal piezoelectric lithotripsy (EPL) in 40 renal units with the following anatomic anomalies: solitary kidney (10), chronic pyelonephritis (8), medulospongiosis (6), caliceal diverticula (5), intrarenal cysts (5), pyeloureteric duplicity (3), megacaliosis (1), horseshoe kidney (1), and ureterocele (1). Adequate stone fragmentation was achieved in 80% of the patients with solitary kidney; 20% developed obstructive complications (1 patient with a 15 mm.-stone and 1 patient with obstruction of double-J catheter). At 6 months, stone remnants persist in 71.4% (5/7) after stone fragmentation in those cases with pyelonephrosis. The rates for fragmentation, elimination of remaining stone fragments, and disappearance of pain are 80%, 50% and 100% for diverticular caliceal calculi, and 67%, 50% and 100% for those in kidney with medulospongiosis. We can conclude that placement of a double-J catheter is useful before EPL in patients with solitary kidney and calculi greater than 10 mm. EPL is the first therapeutic approach in symptomatic lithiasis in caliceal diverticula or precaliceal cystic dilatation (medulospongiosis).

[False positive urinary cytology. Diagnostic and prognostic value in the detection and surveillance of urothelial tumors. Apropos of 57 false positive cases in a series of 1000 cytologies]. / Les cytologies urinaires "faussement positives". Valeur diagnostique et pronostique dans le dépistage et la surveillance des tumeurs urothéliales. A propos de 57 cas de "faux positif" sur une série de 1,000 cytologies.

Out of 1,000 optical cytological urine tests carried out over a period of two years, 84 isolated cases were "positive" and alerted 57 patients. These cases are analyzed by the authors with a follow-up period of 48 to 72 months: among those patients already under supervision for urothelial tumours, 40.4% showed urothelial recurrence of which 70%, that did not appear to carry a worse prognosis, were detected in the first twelve months. Since these patients usually underwent annual endoscopic examination, this meant that for 20% (i.e. 4.15% of the group under supervision) the diagnosis of recurrence could be made at least 6 months earlier. This alone is a justification for cytological examination which does not involve any complications but merely entails increased cystoscopic and biopsy tests. On the other hand, there appear to be no grounds to advocate mass "screening" except in populations with warning symptomatology (especially haematuria) for which the ratio of positive findings in this series was 2.3/1,000. The future development of automatic apparatus for cytological tests should obviate the significant personal factor involved in cytological examinations, as shown by a review of the literature.

[Preventive value of intravesical thiotepa on the recurrence of Ta-T1 vesical tumors treated by conservative surgery. Apropos of 247 cases a mean follow-up of 88 months]. / Valeur prophylactique du thiotepa intra-vésical sur les récidives des tumeurs vésicales Ta-T1 traitées par chirurgie conservatrice. A propos de 247 cas suivis avec un recul moyen de 88 mois.

The retrospective homogeneous study of 247 patients with follow-up from 12 months to 384 months (mean 88 months) and managed with or without intra-vesical instillations of thiotepa as prophylactic chemotherapy after surgical conservative treatment is compared with some literature's data principally multicentric randomized series. Statistics contradictions remain with no significative results for possible progression towards infiltration, better "free interval" between recurrences, and better recurrence rate for 100 patients/months. In this series the number of tumors recurrences in each bladder was evaluated: this mean rate of tumors recurrences/year is 1,7 without prophylactic thiotepa and only but always 1,08 with thiotepa. Prophylactic instillations chemoprophylaxy seems to be justified but must be emphasized: mitomycin C, BCG therapy would be better in the future?