The effect of surgical mucosectomy on the intestine and its possible clinical consequences

Mucosectomy may be part of many surgical procedures for several indications. Ex-vivo mucosectomy is also used by researchers and pathologist to explore and study 3D structure of the enteric nervous system. Besides, in-vivo mucosectomy with endoscopic submucosal dissection (ESD) became a standard minimally invasive treatment option for early non-invasive gastrointestinal (GI) cancers without regional lymph node metastases. ESD usually is well tolerated however scar formation, stricture at the surgical site with large areas resected is a known complication. The ileum and colon are the most commonly used donor organs for bladder augmentation, however the presence of intestinal mucosa within the augmented bladder is associated with significant complications, such as urinary tract infection, stone formation and adenocarcinoma development. Not surprisingly, extensive research has been carried out to reduce the risk associated with the presence of intestinal mucosa in the augmented bladder. Composite flaps with cultured urothelium coverage after mucosectomy in experimental settings seemed to be a viable and promising approach but the experimental results were not translated into clinical practice and contraction and stricture of the intestinal flaps is still major concern. Similar experimental attempts have been made to create composite intestine transplanting small bowel mucosa in the colon after colonic mucosectomy to increase absorptive surface in severe short bowel syndrome assuming the colon will remain functional after mucosectomy. The link between ischemia and postoperative fibrosis is relatively well known but the exact mechanism of stricture formation after mucosectomy is still less understood. Our main goal, therefore, was to study and characterize the effects of mucosectomy on the intestinal microperfusion and the enteric nervous system (ENS), to investigate and define the potential contribution of these intramural factors to the negative postoperative consequences. We have carried out our investigation in two separate but inter-related studies using anesthetized minipigs. We have demonstrated that mucosectomy results in an abrupt cessation of the microcirculation of the intestinal wall without significant recovery within the warm ischemia time. Significant disruption of the ENS with broken reflex circuits of the intestinal segments were demonstrated histologically with prompt intestinal contractions in vivo. These findings may influence the direction of research in reconstructive surgery and urology: the stricture seen after extensive mucosectomy remains invertible, composite intestinal segments with transplanted mucosa may not be viable longer term if immediate microvascular and neurological damage of the intestinal segment are not addressed

A rövidbél-szindróma korszerű sebészi kezelése: autológ rekonstrukció és intestinalis rehabilitáció = Autologous reconstructive surgery and intestinal rehabilitation in the management of short bowel syndrome

Absztrakt: A legújabb definíció szerint rövidbél-szindrómának nevezzük a bél jelentős hosszának elvesztése után kialakuló elégtelen bélműködés tünetegyüttesét, melyben a homeostasis és fejlődés-növekedés csak a hiányzó víz és elektrolit, illetve makrotápanyagok parenteralis pótlásával tartható fenn. A rövid bélben lezajló lassú természetes adaptációs folyamat a veszteséget csak bizonyos mértékben képes kompenzálni. Ennek megfelelően megkülönböztetünk (1) akut, (2) elhúzódó és (3) krónikus típust. A kórkép a leggyakrabban gyermekkorban jelentkezik nekrotizáló enterocolitis, malrotatio, volvulus, hasfalzáródási rendellenesség és ilealis atresia következményeként. A legnagyobb kihívást a krónikus típus ellátása okozza, bár a multidiszciplináris szemléletnek köszönhetően folyamatosan javul a betegek hosszú távú túlélése és életminősége, béltranszplantációra egyre ritkábban van szükség. A szerzők célja az intestinalis rehabilitáció legfontosabb szempontjainak – fokozott gasztrinszekréció, „high-output” stoma, csökkent tranzitidő, a centrális vénás kanülök ápolása, az enteralis, illetve parenteralis táplálás és az adaptáció serkentése – összegzése mellett a legújabb sebészi kezelési lehetőségek, köztük az autológ intestinalis rekonstrukció (AIRS) módszereinek, a passzázslassításnak (az ileocoecalis billentyű pótlása), a „bélhosszabbítás”-nak (LILT, STEP, SILT) és a felszívófelszínt növelő eljárásoknak (kontrollált bélexpanzió) az áttekintése volt. Ezeken túl a szerzők érintik a jelenlegi kutatások (disztrakciós enterogenezis, ’tissue engineering’) legújabb eredményeit. Orv Hetil. 2020; 161(7): 243–251. | Abstract: Based on the latest definition, short bowel syndrome is defined as intestinal failure due to the loss of significant small bowel length or function, when the homeostasis and growth can only be maintained with intravenous supplementation of fluid, electrolytes and macronutrients. The natural adaptation of the short bowel can only compensate for the loss up to a certain level. According to this, we differentiate (1) acute, (2) prolonged and (3) chronic types of intestinal failure/short bowel syndrome. The most common causes are necrotising enterocolits, intestinal malrotation and volvulus, gastroschisis and ileal atresia. The management of type 3 short bowel syndrome has evolved significantly during the last decades, due to the multidisciplinary approach, hence the survival and quality of life of the patients have improved and transplantation is rarely necessary. Our aim was to review the most important considerations of intestinal rehabilitation, like management of increased gastrin secretion, high output stoma, decreased transit time, central venous lines, enteral and parenteral nutrition and the enhancement of the natural adaptation. We reviewed the former and the latest options of the autologous intestinal reconstructive surgery (AIRS) like the reversed segment, small bowel interposition, ileocaecal valve replacement, bowel lengthening and tailoring (LILT, STEP and SILT), controlled bowel expansion and the latest results with distraction enterogenesis and tissue engineering. Orv Hetil. 2020; 161(7): 243–251