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Biomedical subjects

C Ell

Publications and source records attributed to C Ell.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1990

[Extracorporeal shock-wave lithotripsy of a salivary stone].

Ultrasonography revealed a 12 mm concrement in the left parotid duct of a 67-year-old man with an acute exacerbation of a left-sided purulent parotitis. After the acute phase had subsided under antibiotic therapy it was not possible to remove the stone either by bougie or cutting into the duct close to the papilla. Piezoelectric shockwave lithotripsy with a total of 1000 shock-waves fragmented the stone, and sonography 48 hours and four weeks later demonstrated that the parotid gland was free of stone.

Aged↗
PubMed1990

Piezoelectric lithotripsy: stone disintegration and follow-up results in patients with symptomatic gallbladder stones.

One hundred symptomatic patients with radiolucent gallbladder stones were treated with a new piezoelectric lithotripter and oral chemolitholytic agents. Stone disintegration was achieved in 99 of these patients (99%) with a mean (+/- SD) maximum fragment size of 5.1 +/- 4.1 mm. Significant differences were found when the mean (+/- SD) fragment sizes of single stones less than or equal to 20 mm (4.2 +/- 2.5 mm) were compared with those of single stones greater than 20 mm (5.8 +/- 3.4 mm; P less than 0.05) and multiple stones (6.2 +/- 3.8 mm; P less than 0.05), respectively. None of the patients required anesthesia, analgesics, or sedatives before or during the treatment. The stone-free rates for all patients followed up for up to 4-12 months (mean +/- SD, 10.7 +/- 2.9 months) were 18% (1 month), 25% (2 months), 38% (4 months), 52% (8 months), and 67% (12 months). Partly significant differences were obtained in stone-free rates for single stones (less than or equal to 20 mm) compared with larger stones (greater than 20 mm) and multiple stones (P less than 0.05), respectively. Serious adverse reactions (i.e., cholestasis and pancreatitis) were observed in only 3 patients (3%). These conditions were induced by fragment impaction in the common bile duct. In 2 of these patients, endoscopic retrograde cholangiopancreatography with endoscopic sphincterotomy was required. It is concluded that piezoelectrically generated shock waves are suitable for the effective and safe disintegration of gallbladder stones in humans. The anesthesia-free and analgesia-free shock-wave application opens up the possibility to perform biliary lithotripsy as an outpatient procedure. The stone-free rate achieved in combination with oral bile acids is most promising for single stones (less than or equal to 20 mm).

Adult↗
PubMed1990

[Tissue reactions with administration of piezoelectric shock waves in lithotripsy of salivary calculi].

Before clinical application of an extracorporeal piezoelectric lithotripter to treat sialolithiasis, tissue reaction during shockwave application was examined in vitro and in experiments with animals. Application of shockwaves to human tissue in vitro showed neither macroscopic nor microscopic effects. In animal experiments, the acute experiment (16 rabbits, Chinchilla-Bastard) revealed minor bleeding in the parenchyma of the parotid gland, while the chronic experiment (14 rabbits, Chinichilla-Bastard) revealed no morphologic tissue damage to the parotid region of the rabbit, as a result of piezoelectric shockwaves. However, when the eye was placed in the shockwave focal area and the shockwaves were transmitted via the fissura orbitalis to the endocranium, brain damage could be detected morphologically. In conclusion, the authors feel that the clinical application of extracorporeal piezoelectric fragmentation of salivary stones is justified, provided that a reliable positioning of the patient and exact sonographic location of the concrement are possible.

Animals↗
PubMed1990

[Extracorporeal piezoelectric lithotripsy of salivary calculi. Initial clinical experiences].

Piezoelectric lithotripsy was performed in 14 patients with salivary stones. None of the patients required anaesthesia, analgesics or sedatives. All of the salivary stones could be fragmented totally during the first lithotripsy procedure. Three months after treatment with extracorporeal shock waves all the patients were free of symptoms and in 7 out of 14 patients no concrement could be found by sonography. The piezoelectric lithotripsy of salivary stones had caused no serious side effects as proved by clinical, biochemical, sonographic and magnetic resonance imaging examinations. Extracorporeal piezoelectric lithotripsy is a new and promising non-surgical therapy for selected cases of sialolithiasis of the large salivary glands of the neck.

Adult↗
PubMed1989

[Dissemination of endoscopic procedures in gastroenterology. A survey of hospitals in West Germany].

With the aim of establishing the prevalence of diagnostic and therapeutic endoscopic procedures in the field of gastroenterology, a survey was conducted of the medical and surgical departments of university hospitals as well as of all other hospitals in the FRG. Of the 1,382 hospitals approached, 1,116 (80.7%) provided the information required. An analysis of the data revealed that in the medical departments of university hospitals, virtually all the diagnostic and therapeutic endoscopic procedures are practised, with the exception laser therapy, endoprosthesis implantation and local chemolitholysis. Also, the diagnostic endoscopic procedures have become firmly established in the surgical departments of the university hospitals and the general medical hospitals in the Federal Republic. In contrast, therapeutic endoscopy has not met with unqualified acceptance in the surgical departments of the university hospitals (in particular the pancreo-biliary system) and in the small to medium-sized medical-gastroenterological hospitals (less than 100 medical beds) (in particular endoprosthesis implantation, laser therapy and variceal sclerotherapy).

Endoscopy↗
PubMed1989

Fragmentation of biliary calculi by means of extracorporeally generated piezoelectric shock waves.

A new extracorporeal piezoelectric lithotripter was tested for its gallstone disintegration capability. A total of 177 surgically removed gallbladder stones were submitted to piezoelectric shock-wave treatment. Prior to shock-wave application, the diameter, weight, and volume of all the stones and CT density and MR signal intensity of selected stones were determined. After shock-wave application, the chemical composition of the stones was investigated by x-ray diffractometry and/or infrared spectrometry. All the stones (maximum diameter 6-30 mm) were successfully fragmented; calculi with a maximum diameter of 17 mm, a maximum weight of 1800 mg, and a maximum volume of 2 cc were regularly disintegrated into fragments less than or equal to 4 mm. The number of shock waves required correlated most closely with volume (r = 0.82, P less than 0.001), weight (r = 0.81, P less than 0.001) and, to a somewhat lesser degree, diameter (r = 0.62, P less than 0.001). No correlation was found between the chemical composition, CT density, or MR intensity of the calculi and the number of pulses needed for fragmentation.

Cholelithiasis↗
PubMed1989

Extracorporeal piezoelectric shockwave lithotripsy of multiple pancreatic duct stones under ultrasonographic control.

The first ultrasonographically controlled fragmentation of multiple pancreatic duct stones of up to 14 mm size by means of extracorporeal, piezoelectric shockwave lithotripsy is reported. On account of the ultrasound localization and continuous control during therapy a nasopancreatic tube for instillation of contrast medium and frequent x-ray checks were not necessary. The 48-year-old patient did not experience any pain during the four treatment sessions and during the follow-up period. No complications were noted.

Calculi↗