[Focused extracorporeal pyrotherapy. Initial experimental results]. / Pyrothérapie extra-corporelle focalisée. Premiers résultats expérimentaux.

The objective of this study was to develop an apparatus allowing the generation of a high temperature (exceeding 80 degrees C) in a precise focus (20 mm x 2 mm) by means of extracorporeal elastic waves. The treatment time at high temperatures is brief and administered in sequences of 4 to 7 seconds. In vitro studies on blocks of polyurethane demonstrated melting of the plastic at the focal point. Studies on plastic spheres introduced into the bladder of the pig demonstrated melting of the sphere without any alteration in the tissues in the wave path. Studies of cellular viability of bladder carcinoma cultures demonstrated a significant difference after 48 hours between the non-treated control group and the group of cells submitted to high temperatures. This technique, called Pyrotherapy, should be promising if the preliminary results are confirmed.

Focussed extracorporeal pyrotherapy: experimental results.

A new device made of piezoelectric ceramic placed in a semispherical dish and focussed at 320 mm was developed in order to generate heat and cavitation responsible for coagulative necrosis of deep tissues. The target to be treated is located with a central ultrasound probe of 3.5 MHz. In vitro studies with polyurethane phantoms showed that the ultrasound melted a surface of 2 x 12 mm within 1 s. The temperature recorded at the focus was 270 degrees C. In tissue samples (prostate cancer and benign prostate hyperplasia), the temperature rose to 85 degrees C in vitro and a hyperechoic zone appeared at the focus during shots. In vivo 8-mm plastic spheres, introduced surgically into the bladder of pigs, were melted by repeat shots without burning of crossed tissues. These studies were performed in the kidney and the liver. Autopsy performed on day 0 showed congestion, autopsy performed between day 6 and day 11 showed necrosis, whereas at 3 months the focussed area was fibrosed. This technique, which we called 'focussed extracorporeal pyrotherapy', combines phenomena of cavitation and high heat at the focus. Prostate tumors, bladder tumors, kidney tumors and liver metastases are potential indications for pyrotherapy.

[Technic, failures and complications in the extraction of ureteral calculi using a rigid ureteroscope]. / Technique, échecs et complications de l'extraction des calculs de l'uretère par urétéroscopie rigide.

The authors describe the technique for the removal of ureteral stones by ureteroscopy. They stress the need to use perfectly suitable instruments (ureteroscope, baskets and ultrasound or hydro-electric lithotrites), and the importance of extreme gentleness in the manipulations and great patience. The time taken to perform a simple ureterostomy should not be compared to the time necessary for a complex endoscopic extraction. The quality of the dilatation counts for three quarters of the success. Fluoroscopic monitoring facilitates the operation. Ureteral drainage is necessary in the case of a long or fairly traumatic operation, or if there is urinary infection. With these precautions, rigid ureteroscopy can be used for three quarters of ureteral stones. Only one serious complication was registered: the rupture of the pelvic ureter during the extraction of a voluminous lumbar stone.

[Single-dose preventive treatment of urinary tract infections after endoscopic resection of the prostate]. / Traitement prophylactique minute des infections urinaires après résection endoscopique de la prostate.

The ability of mezlocillin to prevent urinary tract infection after trans-urethral prostatectomy was evaluated in a randomized trial involving 100 patients (49 treated and 51 controls) with bacteria-free urine prior to surgery. One single 2 g dose of the antibiotic was administered intravenously 1 hour before the operation. Mezlocillin was chosen on the results of a preliminary study of post-trans-urethral prostatectomy urinary tract infections in 150 patients and was given as a single dose to prevent the development of multiresistant strains. Both groups of patients were comparable with regard to age, percentage of malignant tumours, weight of resected tissue and duration of post-operative bladder catheterization. Following surgery, bacteriuria (greater than or equal to 10(5) organisms/ml) was present in 18.4% of treated patients and in 51% of controls (p less than 0.001), the difference being significant on the 2nd and 5th post-operative days (p less than 0.01 and p less than 0.05 respectively). Clinical signs of infection were less frequent, and the duration of post-operative stay in hospital was reduced by more than 1 day in the treated group.