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Biomedical subjects

K Schaarschmidt

Publications and source records attributed to K Schaarschmidt.

At least 37 records · Page 2Linked to original sources
PubMed1996

Laparoscopic and thoracoscopic surgery in infancy and childhood, the Münster/Gent experience.

Laparoscopic and thoracoscopic surgery have had a tremendous impact on adult surgery, but are still rarely used in children. In the past 3 years 168 children have been treated endoscopically in the three cooperating institutions. The course of all patients was documented prospectively in order to determine the value and prove the safety of endoscopic surgery in children. The operations performed endoscopically comprised appendectomy (n = 39), diagnostic procedures (24), adhesiolysis (n = 22), cholecystectomy (n = 13), bowel resection (n = 8), pyloromyotomy (n = 6), ovarial resection (n = 6), hiatus hernia repair (n = 22), splenectomy (n = 6), first stage of Fowler-Stephens operation for kryptorchidism (n = 3) and interruption of persistent botallic ducts (n = 6) in preterm infants. Apart from four wound infections (2.4%) following perforated appendicitis, one of which required laparotomy for perityphlitic abscess there were no serious complications. No patient died, and overall morbidity related to the procedure was 1.8% (i.e. incidence of uneventful minor intraoperative complications). Furthermore endoscopic surgery provides a better diagnostic survey of the abdomen or thorax so that missing of secondary pathology is unlikely. Pain and reflectory impairment of bowel-function or respiration were diminished, the aesthetic results were excellent and hospitalization could be reduced to a minimum. It is concluded that laparoscopic and thoracoscopic surgery are safe and reliable procedures for children and yield very encouraging results.

Adolescent↗
PubMed1996

[Assessment of the resectability of Wilms' tumors in childhood].

Over the last ten years 62 children were operated for renal tumours. The therapeutic aim in Wilms' tumours is complete macroscopic resection of the primary tumour, assessing resectability as accurately as possible. Overestimating surgical possibilities may lead to intraoperative rupture of the tumour (three cases), while overestimating local tumour extent may result in too much preoperative chemotherapy, which resulted in the life-threatening complication of venous occlusive disease of the hepatic veins (VOD) in three infants. The assessment of resectability may become particularly problematic in bilateral (six cases) or multifocal Wilms' tumours (two cases), and in nephroblastomatosis (two cases), i.e. the persistence of embronal renal tissue, a facultatively precancerous lesion, which requires quarterly sonographic controls and which induced a second metachronous contralateral Wilms' tumour in one child.

Adolescent↗
PubMed1995

Tracheoesophageal anastomosis, continent gastrostomy and oesophagostomy--a new experimental model in minipiglets.

Tracheoesophageal fistulae endanger newborn children by aspiration pneumonia. An animal model of this dangerous malformation was thought to be impossible until now. By tracheoesophageal anastomosis, occlusion of the oesophagogastral junction, proximal cervical oesophagostomy and continent gastrostomy in 25 minipiglets a reliable model of tracheoesophageal fistula has been developed. After establishing the model in a pilot study the mortality following the establishment of this procedure was 5.6% and the minipiglets survived in excellent condition for 2-10 week periods under complete alimentary restriction and gastrostomy feeding. Therefore the method seems to be suitable for long-term investigations on major oesophagotracheal surgery.

Anastomosis, Surgical↗
PubMed1995

The interaction of laser energy with ureter tissues in a long-term investigation.

This study investigates tissue responses after laser irradiation of the rabbit ureter, which serves as an experimental model for rectourogenital fistulae of children. Twenty-five rabbit ureters were irradiated intraluminally by a Nd:YAG laser 1320 nm (2 Watt, 20 seconds and 3 Watt, 8 seconds) via an applicator with radialsymmetrical light distribution. Immediately, 2 weeks, 4 weeks, 8 weeks, and 16 weeks after irradiation, the ureters were X-rayed with contrast solution and prepared for light and transmission electron microscopy. For the parameters employed, no apparent morphological differences could be observed. Immediately, the central laser zone showed a transmural thermonecrosis prevailed by cellular destruction, condensed ground substance and occlusion of most vascular lumina. Peripheral laser zones displayed urothelial vacuolations. Between 2 and 16 weeks, urothelial regeneration and ingrowth of granulation tissue caused a luminal stenosis or occlusion followed by transformation into scar tissue. In some peripheral laser zones, a hydroureter with marked luminal dilatation developed. We conclude that the ureter is occluded if the expanding force of the growing scar tissue exceeds the hydrostatic pressure of the obstructed urine. A laser occlusion of rectourogenital fistulae will be easier to achieve since fistula occlusion does not entail an obstruction of the urine flow.

Animals↗
PubMed1995

The morphological tissue response of the piglet oesophagus to experimental irradiation by 1320 nm Nd:YAG laser.

The oesophagus of 18 minipiglets was exposed to endoscopic intraluminal irradiation with a 1320 nm Nd:YAG laser (10 W, 20 s) via a radial applicator with strictly radially symmetric light distribution. Immediately and at 2, 3, 4 and 8 wk after irradiation, the oesophagus was perfusion-fixed and filled with contrast solution. Radiographs were taken for evaluation by microradiometry. The specimens were subsequently prepared for light and transmission electron microscopy. The immediate reaction to irradiation was a morphological gradient of damage extending from the centre of the laser exposure where there was cellular thermonecrosis in all layers of the wall and condensation of the extracellular matrix, to a peripheral zone (at a distance of up to 8 mm from the region where the laser was centred) which showed only minor tissue damage manifested by intracellular vacuolation. In this zone dilatation of most vascular lumina was prominent. In the period between 2 and 8 wk after irradiation all phases of wound healing were observed and resulted in occlusion of the lumen of the oesophagus by early scar tissue after an interval of more than 3 wk at the former centre of laser exposure. Peripherally, epithelial regeneration resulted in a new luminal lining. Both the process of epithelial regeneration and that of fibrous repair indicated a good reparative capacity of laser-irradiated oesophageal wall tissues resembling the phases of normal wound healing. The immediate laser interaction with tissue indicated that the noncellular matrix components of tissues are more resistant to the photothermal effect than the cellular components.

Animals↗
PubMed1995

The effect of ArF-excimer laser irradiation of the human enamel surface on the bond strength of orthodontic appliances.

This study investigated enamel laser conditioning as an alternative to acid etching in bracket therapy. In preliminary experiments optimal laser parameters for achieving a bond strength of 6-10 N/mm2 were defined. Enamel surface morphology was assessed and the ablation depth was measured on serial enamel sections. Thirty human molars were exposed to 193 nm ArF-excimer laser radiation (energy density: 260 mJ/cm2) by single pulse application of 23 nanoseconds. Thirty molars were etched with phosphoric acid (37%) for 60 seconds. The brackets from the treated molars and 30 untreated molars were debonded vertically for tensile bond strength measurement. Roughened enamel surfaces were attained by 450 and 900 laser pulses with a mean ablation depth of 10.13 +/- 4.84 microns. After 1-10 laser pulses, the enamel surface appeared intact. The tensile bond strength was 6.63 +/- 2.18 N/mm2 in the laser-treated group (1 pulse), 8.75 +/- 3.61 N/mm2 in the acid-etched group, and 4.61 +/- 3.15 N/mm2 in the untreated group. We conclude a laser-selective ablation of the membranous enamel pellicle. Since the irradiated area can be adapted to bracket base and the enamel surface remains morphologically intact, pulsed ArF-excimer laser treatment seems to be superior to the acid etching technique.

Acid Etching, Dental↗
PubMed1993

[The cell response of rat esophagus after intraluminal irradiation with Nd-YAG-laser (1064 nm) after various postoperative times: a light and electron microscopic study].

The esophagi of Wistar rats were irradiated by a Nd-YAG-laser and studied by light and transmission electron microscopy immediately, 2 days and 14 days after the operation. In the immediate group the lasercentre showed a destruction of the stratified epithelium. On the contrary the cells and fibres of the underlying connective tissue were hardly affected. In the lasercentre we have found occlusion of microvascular lumina. Both the layer of smooth muscular tissue and the layer of skeletal muscular tissue showed defects in their myofilaments and altered nuclei. The damage of the skeletal muscle fibres extended up to 4 mm distant from the lasercentre. After 2 days a migrating epithelial sheet was present below the necrotic epithelium and an inflammatory reaction was found in the connective tissue. After 14 days a new regenerated epithelium and an underlying granulation tissue had caused a stenosis of the esophageal lumen. The smooth and striated muscle fibres also showed signs of regeneration. We assume a high regenerative capacity of all involved tissues.

Animals↗
PubMed1992

Intraanal ultrasound: a new aid in the diagnosis of pelvic processes and their relation to the sphincter complex.

Intraanal ultrasound provides a very accurate structural analysis of the continence organ. In addition it proved to give excellent pictures of solid or fluid intrapelvic, particularly retrorectal, structures. It is superior to computed tomography and magnetic resonance imaging (requiring anesthesia), because the scanner is very close to the structures in question. This allows high scanner frequencies with resolutions of 0.9 mm and better. It is a quick method, avoiding radiation, and can be safely repeated as often as necessary.

Abscess↗
PubMed1992

Delayed primary reconstruction of an esophageal atresia with distal esophagotracheal fistula in an infant weighing less than 500 g.

Delayed primary reconstruction of an esophageal atresia (Vogt IIIb) was undertaken in an extremely small-for-date baby (second twin, 36th week) with a birth weight of 445 g. After initial insertion of a gastrostomy under local anesthesia on the 29th day of life, ligation of the fistula and end-to-end anastomosis were performed by transpleural access (weight then, 535 g). There were no complications related to the operative procedure. The baby weighed 1,600 g at the age of 8 months.

Diseases in Twins↗
PubMed1992

The rat esophagus: ultrastructure and radiological aspects of tissue response after 1320 nm Nd:YAG laser irradiation.

Morphological tissue response towards laser treatment was investigated in the esophagi of adult Wistar rats by light- and transmission electron microscopy. The specimens were fixed by perfusion immediately, 2 days and 14 days after laser treatment in order to assess different stages of the healing process. The epithelium of the lasercentre was completely destroyed in the immediate group. The connective tissue showed damaged cells, fused collagenous fibres and occluded blood vessels. Smooth muscle cells presented a vacuolated sarcoplasm and pycnotic nuclei. The cross striation of skeletal muscle cells had disappeared and their nuclei were karyolytic. In a distance of 4 mm from the lasercentre all wall tissues had an almost normal appearance. After 2 days the morphological feature of the lasercentre was the same as in the immediate group. In a distance of 2 mm some layers of flat and intact epithelial cells were observed below the necrotic epithelium. The adjacent connective tissue was infiltrated by inflammatory cells. After 14 days the formation of granulation tissue had caused an occlusion of the lumen in the lasercentre. In a distance of 2 mm the lumen was patent and the wall tissues had been partly restored. As the rat esophagus serves as a model for esophagotracheal fistulae in newborn children we assume the 1320 nm Nd:YAG laser to be a possible application in occlusion of these fistulae.

Animals↗
PubMed1992

A new device for long-term continuous enteral nutrition of rats by elementary diet via gastrostomy, following extensive oesophageal or lower gastrointestinal surgery.

A device for intragastric nutrition of unsedated and minimally restrained rats under complete alimentary abstinence has been developed. The cannulation system consists of an infusion pump, modified glass syringe as flow swivel, rat-harness and a silicone-tube-gastrostomy. The animals were kept in special cages and coprophagy was prevented by an own model of faecal collection cup. Methionine and Ca-glycerophosphate had to be added to a commercial elementary diet. The rats were allowed to move freely during intragastric infusion, which was applied for 14 to 28 days in 118 Wistar-rats (350-400 g). They maintained weight on an energy supply of 86.4 kcal/day.

Animals↗
PubMed1991

Light- and electron-microscopic study of the rat esophagus following intraluminal argon laser irradiation.

36 rat esophagi were irradiated by argon laser via an applicator with circumferential light distribution. They were perfused with glutaraldehyde and studied by light and transmission electron microscopy immediately, 2 days and 14 days after irradiation. Immediately after irradiation the laser center showed destruction of the keratinized stratified squamous epithelium. The collagenous fibers of the connective tissue were altered; fibrocytes and fibroblasts were severely damaged, and the microvascular lumina were occluded. The smooth muscle tissue and skeletal muscle tissue showed myofilament defects and initial karyonecrosis. There was decreasing damage of both fiber types up to 4 mm from the laser center. After 2 days the morphology of the laser center was not different from that seen immediately after irradiation. At a distance of 2 mm a partly differentiated new epithelium emerged below the necrotic epithelium. An inflammatory reaction was found in the connective tissue. After 14 days the esophageal wall was replaced and the lumen was occluded by young granulation tissue in the former laser center. Peripherally the esophageal wall appeared almost normal. As the rat esophagus serves as a model for esophagotracheal fistulae in newborn children, our findings indicate that the argon laser should be capable of occluding these fistulae likewise.

Animals↗
PubMed1991

[Improved model of a fecal collection device for the prevention of coprophagia in the rat].

Previous fecal collection cups with tape fixation frequently led to serious necroses of the rat tail due to strangulations, and did not allow for growth of the tail. A recently developed new model gives space for rapidly growing tails and is securely fixed by a cannula perforating both fecal collection cup and tail. It is transparent, cheap to be made, and easy to empty and was tested in 118 animals for two and four weeks. In no case the cup did loosen or had to be removed due to infections, strangulations or any local problems.

Animals↗
PubMed1989

Clinical relapse of Crohn's disease under standardized conservative treatment and after excisional surgery.

The course of 205 patients with Crohn's disease at one gastroenterological center was studied in patients with conservative drug treatment or with operative management of their disease. The decision for one or the other treatment regimen was made by an interdisciplinary team of gastroenterologists and surgeons. Using life-table analysis the 205 patients showed a clinical relapse rate of 27% after two years and 38% after four years. Clinical relapse was defined by a Crohn's disease activity index (CDAI) over 150. We used a standardized drug regimen of salazosulfapyridin and prednisone; the indication for excisional surgery was limited strictly to life-threatening situations, absolute nonresponse to drug treatment, and severe intervisceral fistulae. The operated patients (N = 93) had a lower relapse rate than the patients treated conservatively (N = 112), 20% and 51%, respectively, after four years. There were considerably fewer relapses in Crohn's colitis patients who were operated upon than in conservatively treated patients (18% versus 67% after four years); the same was found for ileocolitis (20% vs 49% after four years), but there was no difference between the treatment groups in ileitis (25-30% relapses for both after four years). In addition the patients with Crohn's disease of the colon had a more favorable course after resection with respect to symptoms, clinical and laboratory findings, and CDAI in remission. This paper gives data only for surgery in severe clinical situations and does not give a rationale for earlier surgery. This problem should now be studied in a randomized trial.

Adult↗
PubMed1989

[Value of intra-anal ultrasound study for structural analysis of the continence organ--initial results].

Endorectal ultrasound gives a fairly precise anatomical view of the muscular components of the continence organ. The strength of the puborectalis and the external anal sphincter can be measured with an accuracy slightly under one millimeter and consistency can be gauged roughly. Another major use is for the diagnosis of pelvic, particularly retrorectal, processes such as abscesses, tumours or duplication. Short distances between ultrasound probe and process yield a high resolution. The procedure is quick and does not cause any radiation effects (as opposed to CT).

Adolescent↗
PubMed1988

[Pediatric inguinal hernia in continuous ambulatory peritoneal dialysis].

We report on the case of an 11-year-old boy suffering from juvenile nephronophthisis who developed bilateral inguinal hernia (on the right as a recurrence of the neonatal operation) 5 days and 4 months after starting CAPD treatment. Before the peritoneal dialysis there had been no clinical signs and no history of inguinal hernia. On the basis of this we emphasise some particular features of inguinal hernia under CAPD treatment such as an increased risk of incarceration, the importance of genital and scrotal swelling as an early symptom, the value of peritoneography as a diagnostic aid, and the need for high ligation of the patent processus vaginalis together with reduced postoperative volumes of the peritoneal dialysate.

Child↗