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C Ell

Publications and source records attributed to C Ell.

At least 199 records · Page 11Linked to original sources
PubMed1992

Extracorporeal piezoelectric shock-wave lithotripsy of salivary gland stones.

Piezoelectric lithotripsy was undertaken on 19 patients with salivary stones, with none of these patients requiring anesthesia, analgetics, or sedatives. All salivary stones were totally fragmented during first lithotripsy. Four months after treatment with extracorporeal shock waves, all patients were free of symptoms and, in 11 of the patients, no calculi could be found sonographically. The piezoelectric lithotripsy of salivary stones caused no serious side effects which could be proven by clinical, biochemical, sonographic, and magnetic resonance imaging (MRI) examinations. Extracorporeal piezoelectric lithotripsy is a new and promising nonsurgical therapy for selected cases of sialolithiasis of the parotid and submandibular glands.

Adult↗
PubMed1992

Extracorporeal piezoelectric shock wave lithotripsy of salivary gland stones: first clinical experiences.

Piezoelectric lithotripsy was undertaken on 14 patients with salivary stones, none of them requiring anesthesia, analgesics, or sedatives. All salivary stones were fragmented totally during the first lithotripsy session. Four months after treatment with extracorporeal shock waves all patients were free of symptoms, and in seven out of 14 patients no concrement could be found sonographically. The piezoelectric lithotripsy of salivary stones had caused no serious side effects proved by clinical, biochemical, sonographic, and magnetic resonance imaging examinations. Extracorporeal piezoelectric lithotripsy is a new and promising nonsurgical therapy for selected cases of sialolithiasis of the large salivary glands.

Adult↗
PubMed1991

[Imaging procedures prior to the extracorporeal shockwave lithotripsy of gallstones].

In order to determine whether cholecystography and computed tomography (CT) are capable of better gallstone characterization than conventional radiography alone, 91 patients (76 females, 15 males; mean age 47 +/- 12 years) with symptomatic single gallstones were studied prospectively prior to extracorporeal shock-wave lithotripsy with concomitant oral stone dissolution therapy. In addition, the value of oral cholecystography in demonstrating patency of the cystic duct was compared with ultrasound assessment of gallbladder function. Despite "negative" plain gallbladder radiographs in all patients, oral cholecystography showed significant stone calcification in 8 of the 91 patients and CT showed stone calcifications in 52 of the 91 patients. In 12 patients the maximum stone density was between 50 and 90 Hounsfield units, and in 40 patients it was more than 90 Hounsfield units. CT revealed ring-like calcification in the majority (79%) of these stones. Oral cholecystography showed satisfactory concentration of contrast medium in all patients, while ultrasonography of the gallbladder following a chemically defined test meal demonstrated contractility of more than 50% of initial volume in 69 patients and of less than 30% in 9 patients. Although oral cholecystography is a simple, readily available complication-free method, ultrasound assessment of gallbladder contraction is better for selecting patients for extracorporeal shock-wave lithotripsy. CT allows significantly better characterization of gallstones than oral cholecystography and conventional plain gallbladder radiography.

Adult↗
PubMed1991

Lithotripsy of gallstones by means of a quality-switched giant-pulse neodymium:yttrium-aluminum-garnet laser. Basic in vitro studies using a highly flexible fiber system.

The quality-switched neodymium:yttrium-aluminum-garnet laser represents a new instrument for athermal fragmentation of gallstones by transformation of optical energy into mechanical energy in the form of shock waves via local plasma formation. A highly flexible 300-micron fiber transmission system was used in basic investigations to determine the influence of varying pulse repetition rates (5-30 Hz) and pulse energies (15 and 20 mJ) on shock wave intensity and stone fragmentation in vitro for 105 biliary calculi of known size and chemical composition. After performance of 1200 shock wave pressure measurements using polyvinylidenefluoride hydrophones, stone fragmentation was analyzed by determination of fragment removal rates (volume of fragments removed per fragmentation time), ablation rates (mean volume removed per laser pulse), and median fragment sizes for each laser setting. With the quality-switched neodymium:yttrium-aluminum-garnet laser system, all concrements could be reliably disintegrated into small fragments (median diameter, 0.7-1.7 mm). Compared with pure cholesterol stones, a significantly higher fragment removal rate was achieved in cholesterol stones containing 30% calcium phosphate (P = 0.039), in cholesterol stones containing 20% pigment (P = 0.015), and in pure pigment stones (P = 0.007). Fragment removal rates, local shock wave pressures, and median grain sizes were significantly higher at a pulse energy of 20 mJ than with 15 mJ. Shock wave pressures showed a distinct dependence on pulse repetition rates at 20 mJ, yet not at 15 mJ. Because there is no evident hazard of thermal damage to tissue using the quality-switched neodymium:yttrium-aluminum-garnet laser, it appears to be a promising device for nonsurgical biliary stone therapy.

Aluminum↗
PubMed1991

Significance of computed tomography for shock-wave therapy of radiolucent gallbladder stones.

One hundred eleven symptomatic patients (91 women, 20 men) with solitary "radiolucent" stones (proved by a plain radiograph) underwent examination with computed tomography for stone analysis before extracorporeal shock-wave lithotripsy with a second-generation piezoelectric lithoptripter. The aim of the study was to assess the importance of computed tomography as a diagnostic pretreatment procedure compared with the plain abdominal radiograph: computed tomography density values greater than 50 Hounsfield units (HU) were found in 64 of 111 patients with radiolucent stones (58%). Of these 64, 50 patients even had values greater than 90 HU (50/111;45%). The majority of the stones with density values greater than 50 HU had a hyperdense rim (43 of 64) with a mean maximum attenuation of 134 +/- 68 HU. A significantly higher degree of stone disintegration was achieved with stones of group A (less than or equal to 50 HU) than with those in group B (greater than 50 HU and less than or equal to 90 HU) and group C (greater than 90 HU) with respect to the mean maximum fragment size after the first (P less than 0.001) and last (P less than 0.01) lithotripsy and with respect to the total number of shock waves applied (P less than 0.001) and the number of treatments (P less than 0.001). No difference was observed between groups B and C. After all follow-up periods, the rate of complete stone disappearance was higher in group A than in group B (NS for 1, 2, and 4 months of follow-up; P less than 0.01 for month 8; P less than 0.05 for month 12) and group C (P less than 0.05 for 1, 2, and 4 months of follow-up; P less than 0.001 for months 8 and 12). The authors conclude that computed tomographic analysis of gallstones before lithotripsy is more sensitive in detecting nonradiolucent stones than in the plain radiograph. Computed tomographic stone analysis seems to provide a better selection of patients suitable for biliary lithotripsy and could become a standard diagnostic pretreatment procedure to improve stone disintegration and complete stone disappearance after shock-wave lithotripsy and adjuvant chemolitholysis.

Adult↗
PubMed1991

Piezoelectric shock wave lithotripsy of salivary gland stones: an in vitro feasibility study.

The feasibility of fragmentation of salivary stones by a new extracorporeal piezoelectric lithotripter was investigated. A total of 40 salivary stones were submitted to piezoelectric shock wave treatment. The diameter, weight, and volume of all the stones were determined prior to shock wave administration. After shock wave administration the chemical composition of the stones was investigated by X-ray diffractometry. Fragmentation was achieved in 35 out of the 40 (87.5%) stones. Twenty-five of the 40 (62.5%) stones were disintegrated "therapeutically adequate" (residual fragments less than 1.5 mm). A statistically significant correlation was not observed between the number of discharges required for disintegration and the diameter, weight, volume, or the chemical composition of the stones.

Feasibility Studies↗
PubMed1991

[Laser lithotripsy of ureteral stones. Personal experiences].

The in vitro evaluation of a pulsed Nd:YAG laser, showed an effective and fine fragmentation of urinary calculi and showed only minimal subepithelial bleeding in the directly irradiated canine ureter. Since 1989 we have treated ureteral calculi in 30 patients. The laser pulses of 15-20 mJ (at fiber tip), 20 ns, 20-25 cps are transmitted by a 300-microns quartz fiber with a specially formed tip focusing the light. The fiber is passed through an 11.5-F ureteroscope within a guide tube, or, without a guide tube, through one of the new minimized ureteroscopies and is placed in front of the calculus. In 27 patients the procedure was successful, without any residual concretions after 1 day. In our opinion the advantages of this method are the very fine-grained, complete fragmentation of all sorts of calculi, the highly atraumatic procedure, and the absence of either optical or acoustic irritation to the operator.

Adult↗
PubMed1991

[The laser in gastroenterology].

The use of lasers in gastroenterology is an enrichment of the non-invasive therapeutic methods. Prerequisite is their critical use which, in order to be successful, needs a minimum frequency and thus experience. In form of a strictly constructed survey the paper deals with the potential possibilities of laser application and with the alternative approaches being today at our disposal.

Endoscopes, Gastrointestinal↗
PubMed1991

In vitro fragmentation of gallstones: comparison of electrohydraulic, electromagnetic and piezoelectric shockwave lithotripters.

To compare the fragmentation efficiency of three different shockwave systems, 63 human gallstone triplets were disintegrated in vitro using an electrohydraulic (MPL 9000, Dornier), an electromagnetic (Lithostar Plus, Siemens) and a piezoelectric (Piezolith 2300, R. Wolf) lithotripter. Since each stone triplet was obtained from the same gallbladder, the concrements of one such set were identical in physicochemical parameters. According to the maximal diameter, the calculi were divided into group A (6 to 15 mm) and group B (16 to 30 mm). Shockwave application was terminated when residual fragments measured 4 mm or less. Forty-five triplets were fragmented at energy settings mainly used in clinical treatment of patients with gallbladder stones (MPL 9000: 20 kV; Lithostar Plus: setting 9 (maximal); Piezolith 2300: setting 3). The fragmentation endpoint was achieved in group A (n = 3 x 36) with the Piezolith 2300 after median 150 (range = 50 to 500) pulses and with the Lithostar Plus after 150 (50 to 750) pulses compared with 500 (50 to 1,500) pulses using the MPL 9000 (p less than 0.01). In group B (n = 3 x 9) the Lithostar Plus (median = 750, range = 250 to 1,250 pluses) required fewer discharges than the Piezolith 2300 (1,250, 250 to 2,500 pulses; p less than 0.05) and the MPL (1,500, 500 to 1,600 [upper limit] pulses; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Cholelithiasis↗
PubMed1991

[A new applicator for the intraluminal high-dose-rate irradiation of esophageal carcinoma].

Within the framework of multimodal treatment (radiation, chemotherapy) of esophageal carcinoma high dose rate intracavitary irradiation is used either as a boost or with a palliative intention. By use of a set of four tubes of different thickness (diameter 6, 8, 10, 14 mm) it is possible to adapt the diameter of the applicator to the remaining esophageal lumen. Thereby the radioactive source is placed centrally in the esophagus. The distance between the source and the mucosa is maximized and the radiation dose to the mucosa is reduced in comparison to a normal tube with a diameter of 4 to 6 mm. Better depth penetration of the dose can be achieved in deeper parts of the esophageal wall. The applicators are placed using a guide wire during endoscopy. If the malignant stenosis is endoscopically impassable, an intraluminal reduction of the tumours mass is performed by laser therapy or bougienage.

Brachytherapy↗
PubMed1990

[Focal size and shock wave pressure: a comparison of three different physical shock wave generators].

Shock-wave delivery and focal size of three different generators-electrohydraulic, electromagnetic and piezoelectric--were compared. Pressure measurements were uniformly made by needle hydrophone (piezoelectric transducer). The smallest focus, 17 x 3 x 3 mm, was achieved with the piezoelectric system (50% isobars), while the focus with the electromagnetic generator was much larger (50 x 7 x 4 mm). With the electrohydraulic generator the focal size of the 60% isobars was 20 mm in the longitudinal axis. The highest pressure, 1512 bar, was achieved with the piezoelectric lithotriptor (mean shock-wave pressure in focus: electrohydraulic 1000 + 100, electromagnetic 1000 + 25, piezoelectric 1400 + 27 bar). The rapid positive pressure rise was followed by a slower pressure fall and a small negative wave. In the focal region the negative pressure wave was between 112 and 200 bar with the electrohydraulic system, 100-146 bar with the electromagnetic one, and 134 bar with the piezoelectric one. The significance of the negative wave is not clear; perhaps it contributes to the development of the cavitation effect and facilitates stone fragmentation.

Electromagnetic Phenomena↗
PubMed1990

[Acute ulcer hemorrhage and current endoscopic hemostatic procedures].

The introduction of diagnostic and therapeutic endoscopy resulted in a drastic decrease in the mortality rates of acutely bleeding ulcer. In addition to thermal coagulation procedures (electrocoagulation, laser, heater probe), injection techniques (adrenaline, ethanol, polidocanol, fibrin adhesive) are available. A combination of initial injection of adrenaline followed by thermocoagulation, or injection of polidocanol, has proved most effective. In the case of fibrin adhesive, applied by non-traumatic means, controlled studies have yet to be performed. The question as to whether, after endoscopic hemostasis, early elective surgery can be obviated in numerous cases, needs to be investigated by controlled prospective studies.

Electrocoagulation↗