Doctoral theses
Current Record: 927 of 1070
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| Identifier |
000035405 |
| Title |
Πειραματική μελέτη για αύξηση της χωρητικότητας της ουροδόχου κύστης με τροποποίηση της αυτοδιεύρυνσης (autoaugmentation) χρησιμοποιώντας ανθρώπινη σκληρά μήνιγγα (dura mater) και αποβλεννογονοποιημένο τμήμα (Μυικό χιτώνα) στομάχου και λεπτού εντέρου |
| Alternative Title |
Bladder autoaugmentation in the rabbit using de-epithelialized segments |
| Creator |
Nestoridis, George D
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| Abstract |
The concept of autoaugmentation is simple; a large diverticular bulge is created by stripping the detrusor, with dissection at the dome of the bladder, in-creasing the storage capacity of the bladder and decreasing storage pressure if the diverticulum maintains its elastic properties in the long-term. It would appear that for the urothelial diverticulum to persist, a muscular backing should be provided that would preserve the augmenting effect. The methods in the present study avoided the consequences of incorpo-rating gastrointestinal mucosa into the urinary tract and used readily available uro-thelium as an inner lining of the gastrointestinal segments. It was very difficult to remove the mucosa and submucosa to avoid regeneration of the intestinal epithe-lium. The small bowel of the rabbit is thin and friable and cannot tolerate demuco-salization. Although normal saline was injected into submucosa, it was virtually im-possible to find a plane of cleavage between submucosa and muscle so that the submucosal-mucosal layer could be peeled away. When this was tried the intestinal patch was torn, causing haemorrhage and haematoma. The mucosa was de-epithelialized by scraping with a scalpel blade and bleeding was easily controlled be applying direct pressure. Removing mucosa from the stomach was also difficult, although it seems that stomach is an ideal material for demucosalization with dia-thermy dissection in augmentation gastrocystoplasty in huans. In the present experimental model, finding a suitable size of stomach seg-ment to fit the bladder diverticulum was always difficult, because in the rabbit the proportion of urinary bladder to stomach is at least 2:1, a value further increased with the creation of the diverticular bulge. The integrity of the patch had to be pre-served and therefore demucosalization with diathermy dissection could not be used because it would cause fibrosis and contracture by thermal damage. Another reason for avoiding this denuding technique was that it prolongs the oper-ating time and increases post-operative morbidity. Thus, the mucosa was de-epithelialized by scraping with a scalpel and avoiding excessive haemorrhage. Although the histological examination showed evidence of residual intesti-nal mucosa, the urodynamic results showed a significant improvement in bladder capacity and compliance 6 weeks after surgery in group A. Macroscopically, the diverticulum seemed to maintain its elasticity and smooth contour, and microscopi-cally the bladder diverticular urothelium was completely adherent to the intestinal muscle layer. However, this was not so for the animals in group B; at 2 and 6 weeks there was marked shrinkage of the patch and urodynamics showed reduced bladder capacity and compliance. Although gastric muscle used in sheep and hu-mans has shown good results, in the present experimental model the effect was poor probably because of the increased contractility of the segments applied. The rabbits in group C had even worse fibrosis and contracture after 2 weeks, and stone formation at 6 weeks. These findings suggest that LHD is completely unsuit-able for bladder autoaugmentation. In conclusion, in this rabbit model the best material for augmentation was a segment of small bowel which although it could not be completely demucosalized, the epithelium of the bladder diverticulum was maintained intact and retained its elastic properties, producing a good augmenting effect. The segments of stomach and LHD caused fibrosis and graft contracture, and are unsuitable materials for this technique in this rabbit model. Perhaps in future, less traumatic procedures will be developed for the mucosa which might produce better results. The successful out-come with the use of small bowel segments justifies further experimental research which may lead to future clinical application.
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| Language |
Greek |
| Issue date |
1999-12-01 |
| Date available |
2000-03-17 |
| Collection
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School/Department--School of Medicine--Department of Medicine--Doctoral theses
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Type of Work--Doctoral theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/c/c/5/metadata-dlib-1999nestoridis.tkl
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| Views |
306 |
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