eMentorSurgery

Dear students, Thisis only for your revision and NOT A FULL TEXT.

Stomach 

Surgical anatomy

The function -as a reservoirfor ingested food and  break downfoodstuffs mechanically and commence the processes of digestion

Arterial supply

-On the lesser curve theleft gastric artery, a branch of the coeliac axis, forms an anastomotic arcadewith the right gastric artery which arises from the common hepatic artery.

-The gastroduodenal artery,  branch of the hepatic artery, passes behindthe first part of the duodenum, highly relevant with respect to the bleedingduodenal ulcer. - divides into the superior pancreaticoduodenal artery and theright gastroepiploic artery. The superior pancreaticoduodenal artery suppliesthe duodenum and pancreatic head, and forms an anastomosis with the inferiorpancreaticoduodenal artery, a branch of the superior mesenteric artery. Theright gastroepiploic artery runs along the greater curvature of the stomacheventually forming an anastomosis with the left gastroepiploic artery, a branchof the splenic artery.

-The fundus of the stomachis supplied by the vasa brevia (or short gastric arteries) which arise fromnear the termination of the splenic artery.

Veins

-the veins are equivalent tothe arteries, those along the lesser curve ending in the portal vein and thoseon the greater curve joining via the splenic vein. -On the lesser curve thecoronary vein runs up the lesser curve towards the oesophagus and then passesleft to right to join the portal vein.

- markedly dilated in portalhypertension.

Physiology of the stomachand duodenum

-The stomach mechanicallybreaks up ingested food and, together with the actions of acid and pepsin,forms chyme that passes into the duodenum.

-In contrast to the acidicenvironment of the stomach, that of the duodenum is alka­line, as a result ofthe secretion of bicarbonate ions from both the pancreas and the duodenum. Thisneutralises the acid chyme and adjusts the osmolarity to approximately that ofplasma.

-Endocrine cells in theduodenum produce cholecystokinin that stimulates the pancreas to producetrypsin and the gall bladder to contract.

-Secretin is also producedby the endocrine cells of the duodenum. This hormone inhibits gastric acidsecretion and promotes production of bicarbonate by the pancreas.

Gastric acid secretion

The secretion of gastricacid and pepsin tends to run in parallel

-. Numerous factors(neurotransmitters, neuropeptides and peptide hormones etc )for  the gastric acid production.

 -As mentioned above, hydrogen ions areproduced by the parietal cell by the proton pump.

-widely accepted that themost important of these transmitters is histamine, which acts via the H2receptor. Histamine in turn is produced by the ECL cells of the stomach andacts in a paracrine (local) fashion on the parietal cells.

-The ECL cell produces histaminein response to a number of stimuli that include the vagus and gastrin. Gastrinis released by the G cells in response to the presence of the food in the sto­mach.The production of gastrin is inhibited by acid, hence creating anegative-feedback loop. Various other peptides, including secretin, inhibitgastric acid secretion.

Classically,three phases of gastric secretion- by Pavlov 1-. The cephalic phase  2-The gastric phase 3-the intesti­nal phase,

Gastric mucus and thegastric mucosal barrier

-essential to the integrityof the gastric mucosa.

- viscid layer ofmucopolysaccharides produced by the mucus-producing cells of the stomach andthe pyloric glands.

- important physio­logicalbarrier to protect the gastric mucosa from mechanical damage, and also the effectsof acid and pepsin.

-consider­able bufferingcapacity is enhanced by the presence of bicar­bonate ions within the mucous.

-Many factors can lead tothe break down of this gastric mucous barrier. These include bile, nonsteroidalanti-inflammatory drugs (NSAIDs), alcohol, trauma and shock.

-a hypovolaemic - stressulceration in the stomach.

-Peptides andneuropeptides in the stomach and duodenum

-Gastroduodenal motoractivity

                   Hypertrophic pyloricstenosis of infancy

Cause-unknown. (may be that  analogous to achalasia of the oesophagus inwhich there is a failure of the pylorus to relax, leading to the muscularhypertrophy).

Pathology

The classical feature isthat the musculature of the pylorus and adjacent antrum is grosslyhypertrophied,

Clinical features

-a first-born male -mostcommonly affected.

-. Vomiting is thepresenting symp­tom that after 2—3 days becomes forcible and projectile. ( nobile )

- Immediately after vomitingthe baby is usually hungry.

-Weight loss - becomesemaciated and de­hydrated.

- peristaltic waves (Left  to Right).

Imaging

Ultrasonography -theclassical features in the pyloric canal.

-Thin barium meal(Not usual)shows massively dilated stomach.

Differential diagnosis

-        gastro-oesophagealreflux,

-        feedingprob­lems,

-        urinarytract infection

-        raisedintracranial pressure.

Treatment

-        correctthe meta­bolic abnormalities.

-        dehydratedwithlow sodium, chloride and potassium, and a metabolic alka­losis.

-        should berehydrated with dextrose—saline and potassium (2.5 per cent dextrose plus 0.45per cent sodium chloride plus 1 g of potassium chloride per 500 ml of fluid).

-        Surgery is required.

Ramstedt’s operation

-under general anaesthesia,

-possible to perform theprocedure under a local anesthetic.

-transverse incision placedin the upper abdomen over the right

-. The hypertrophied pylorusis delivered and rotated so that its superior surface comes into view

- The incision is madethrough the serosa only and from this point along the whole length of thepylorus and, importantly, the distal antrum. The hypertrophied pylorus - thepyloric mucosa bulges.

Complications ofoperation

-Postoperative pyrexia

-Wound disruption - occur inemaciated subjects.

-wound infection.

                                  Duodenal atresia

This occurs at the point offusion between the foregut and midgut, and therefore lies in the neighborhoodof the ampulla of Vater.

The diagnosis -ultrasound.the characteristic appearance of a dilated stomach and first part of theduodenum (double bubble).

-condition can be confusedwith pyloric stenosis, although in pyloric stenosis vomiting does not startfrom birth.

Treatment is by theoperation of the duodenoduodenostomy

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