A new pressure wave generator for extracorporeal lithotripsy.

A new pressure wave generator has been designed for the Storz Modulith extracorporeal lithotripter. It consists of an electromagnetic cylindrical pressure wave source and a focusing parabolic reflector. Focus size has been designed using electro-acoustic puls forming network (EA-PFN) techniques. Schlieren photographs of the pressure wave are shown. Pressure in the focus is given as a function of PFN charging voltage.

[Initial clinical experiences with mechanical heart stimulation]. / Erste klinische Erfahrungen mit der mechanischen Herzstimulation.

Rhythmical extrathoracic mechanical stimulation can produce cardiac systoles. The study was designed to determine the usefulness of this procedure in bridging the time gap between the occurrence of asystole or symptomatic bradycardia and the beginning of temporary cardiac pacing or the restoration of a sufficiently high spontaneous heart rate. The mechanical stimulator was used on 31 patients. In 10 patients sufficient circulation with palpable pulse in the femoral artery could be restored. Five patients needed temporary electrical pacing. Five of the patients successfully treated mechanically died within 24h of terminal circulatory collapse or electromechanical dissociation. Five patients could be dismissed from hospital, with only one of them needing permanent cardiac pacing. Twenty of the 21 patients who could not be stimulated mechanically died. Seventeen of those showed electromechanical dissociation when treated with transvenous endocardiac stimulation, three suffered from terminal circulatory collapse. In one patient with an instable thorax sufficient circulation could be obtained by extrathoracic mechanical stimulation. Four patients were not stimulated electrically because of old age and polymorbidity. Problems in using the extrathoracic mechanical stimulation are discussed and compared with endocardiac and extrathoracic electrical stimulation.

Modulith SL 10/20--experimental introduction and first clinical experience with a new interdisciplinary lithotriptor.

More than 20 second-generation lithotriptors have been introduced for extracorporeal shock-wave lithotripsy. Despite great technical progress, each machine still has its specific short-comings. In cooperation, Storz Medical (Kreuzlingen, Switzerland) and the Department of Urology (Klinikum Mannheim, FRG), have developed a new lithotriptor designed to overcome these drawbacks. Energy source: Electromagnetic cylinder with paraboloid reflector (40 cm) for focusing, providing a wide range of pressure (190-1,000 bar) and a focal zone of 28 x 6 mm. The focal depth is maximally 15 cm. Coupling and positioning: Water cushion with patient lying on a specially designed 'acoustic cradle' consisting of an impedance-adapted foil. This is integrated in either a manually or automatically operated table. Localization: Coaxial ultrasound probe for real-time scanning and integrated C arm with pulsed fluoroscopy using a virtual focus (moved along x-axis) for stone localization. In 1989, we commenced with the first treatment based on our own in vitro and in vivo studies to determine the range of energy required for safe application. We treated 137 stones (100 caliceal, 19 pelvic and 18 ureteral) in 88 patients. The mean generator voltage was 16 kV (10-18 kV). Successful disintegration was achieved in 83 patients (95%) employing an average of 2,359 impulses (940-3,500). Thirteen percent of the treatments were performed without any anesthesia on lower generator voltage (10-15 kV), whereas the majority of calculi were treated under intravenous analgesia. The 5 failure cases included 2 stones in a caliceal diverticulum. Moreover, 12 patients with biliary calculi (11 gallstones and 1 bile duct stone) were successfully treated; 1 of these cases required a second treatment session.

Fragmentation of gallstones by extracorporeal shock waves.

We treated nine patients with functioning gallbladders containing one to three symptomatic radiolucent stones not larger than 25 mm in diameter, as well as five patients with stones in the common bile duct that were not removable by endoscopic procedures, by means of extracorporeally generated shock waves during general anesthesia. The patients with gallbladder stones received adjuvant treatment with a combination of ursodeoxycholic acid and chenodeoxycholic acid. All gallbladder stones were disintegrated into sludge or fragments with diameters of no more than 8 mm. In six of the nine patients the fragments disappeared completely within 1 to 25 weeks. No adverse effects were detected during a follow-up period of 10 to 34 weeks, except transient biliary pain in two patients, with mild pancreatitis in one. In four of the five patients with common-bile-duct stones, shock-wave treatment permitted stone disintegration and successful endoscopic extraction or spontaneous passage of fragments. We conclude that gallstone disease may be treated successfully and without serious adverse effects by extracorporeally generated shock waves in selected patients.

Shock-wave lithotripsy of gallbladder stones. The first 175 patients.

To substantiate the early results of extracorporeal shock-wave fragmentation of gallstones, we used this nonsurgical procedure to treat 175 patients with radiolucent gallbladder calculi. Chenodeoxycholic acid and ursodeoxycholic acid were administered as adjuvant litholytic therapy. The gallstones disintegrated in all patients except one and completely disappeared in 30 percent of all patients within 2 months after lithotripsy, in 48 percent at 2 to 4 months, in 63 percent at 4 to 8 months, in 78 percent at 8 to 12 months, and in 91 percent at 12 to 18 months. In patients with solitary stones up to 20 mm in diameter, the corresponding values were 45, 69, 78, 86, and 95 percent, respectively. Shock-wave therapy had no adverse effects except cutaneous petechiae (14 percent) and transient gross hematuria (3 percent). One third of the patients had one or more episodes of biliary colic before all the fragments disappeared. Two patients had mild pancreatitis, which necessitated endoscopic sphincterotomy in one. The patient with insufficient stone fragmentation underwent elective cholecystectomy; no additional operations were necessary. Extracorporeal shock-wave lithotripsy combined with medical therapy for stone dissolution is a safe and effective treatment in selected patients with radiolucent gallbladder calculi.