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SMALL BOWEL. OBSTRUCTION. SURYA .K.S 2002 BATCH. Extension– pylorus to cecum Parts– duodenum(21cm ) jejunum & ileum (261 cm.). ANATOMY OF SMALL BOWEL.
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SMALL BOWEL OBSTRUCTION SURYA .K.S 2002 BATCH
Extension– pylorus to cecum Parts– duodenum(21cm ) jejunum & ileum (261 cm.) ANATOMY OF SMALL BOWEL
Mesentry • Suspends small intestine from the postr. abdominal wall • contains blood vessels, nerves, lymphatics & lymphnodes
ANATOMY (Contd…) • BLOOD SUPPLY– supr. Mesenteric vessel • LYMPHATICS—peyers patches-3 sets of mesenteric nodes • NERVE SUPPLYpara sympathetic—vagus,sympathetic—T9,T10
MICROSCOPIC ANATOMY 4LAYERS • MUCOSA • SUB MUCOSA • MUSCULARIS • ADVENTITIA
SMALL INTESTINE FUNCTIONS • TRANSPORT Distension stimulates contractions • MIXING AND PERISTALSIS • ABSORPTION Carbohydrates, proteins direct absorption Lipids converted to chylomicrons Fat soluble vitamins & Minerals Ca+2, FeSO4, B12, Bile Salts
HISTORICAL ASPECTS • HIPPOCRATES– observed & treated • PRAXAGORAS– earliest known operation • 1912– I.V fluids • 1950s– antibiotics and radiographic techniques introduced
TYPES OF INTESTINAL OBSTRUCTION • DYNAMIC – where peristalsis is working against a mechanical obstruction. • ADYNAMIC – where mechanical element is absent. 1. Peristalsis may be absent; eg: paralytic ileus 2. Peristalsis present in a non propulsive form. Eg : mesenteric vascular occlusion
Clinical classification • HIGH • LOW
CLASSIFICATION (Contd..) • ACUTE OBSTRUCTION • CHRONIC OBSTRUCTION • ACUTE ON CHRONIC OBSTRUCTION • SUBACUTE OBSTRUCTION
SIMPLE blood supply is intact STRANGULATED interference to blood flow by hernial rings, adhesions or bands Contd….
DYNAMIC INTRALUMINAL impaction foreign bodies bezoar gall stones INTRAMURAL strictures malignancy EXTRAMURAL bands/adhesions hernia volvulus intussusception ADYNAMIC paralytic ileus mesenteric vascular occlusion pseudo obstruction
PATHOPHYSIOLOGY ABOVE THE LEVEL OF OBSTRUCTION • Obstruction proximal peristalsis is increased proportional to the distance of obstruction • Obstruction not relieved bowel begins to dilate reducn in peristaltic strength flaccidity & paralysis
PATHO PHYSIOLOGY • Distension proximal to obstruction #GAS (nitrogen & hydrogen sulphide) #FLUID (digestive juices) BELOW THE LEVEL OF OBSTRUCN • Normal peristalsis & absorption till empty then contracts and becomes immobile
STRANGULATION • Venous return is compromised increase in capillary pressure local mural distension loss of intravascular fluid & RBCs occurs • Once the arterial supply is impaired, hemorrhagic infarction occurs viability of the bowel wall is compromised translocation & systemic exposure to aerobic & anaerobic organisms with their toxins.
CAUSES OF STRANGULATION • EXTERNAL hernial orifices adhesions/bands • INTERRUPTED BLOOD SUPPLY volvulus, intussusception • INCREASED INTRALUMINAL PRESSURE closed loop obstruction • PRIMARY mesenteric infarction
CLOSED LOOP OBSTRUCTION Occurs when the bowel is obstructed at both the proximal & distal points. There is no early distension of the proximal intestine. When gangrene of the strangulated segment occurs, retrograde thrombosis of mesentric veins results in distension on both sides.
ACUTE INTESTINAL OBSTRUCTION CARDINAL FEATURES • Abdominal pain • Distension • Vomiting • Absolute constipation Visible peristalsis
CONDITIONS WHERE CONSTIPATION IS NOT SEEN • Richter’s hernia • Gallstone obturation • Mesenteric vascular occlusion. • Obstruction associated with pelvic abscess • Partial obstruction
OTHER MANIFESTATIONS • DEHYDRATION • HYPOKALAEMIA • PYREXIA – may indicate 1. onset of ischemia 2. intestinal perforation 3. associated inflammation • HYPOTHERMIA • ABDOMINAL TENDERNESS
Clinical features of strangulation • Presence of shock indicates underlying ischemia • Constant pain • Symptoms usually commence suddenly & recur regularly • Localised tenderness will always be present associated with rigidity/rebound tenderness
RADIOLOGICAL DIAGNOSIS • Obstructed small bowel is characterized by straight segments that are central and lie transversely. No gas is seen in colon • Jejunum regularly spaced valvulae conniventes giving a concertina / ladder effect. • Ileum featureless
At first gas shadows appear followed by fluid levels. • Number of fluid levels is directly proportional to the degree of obstruction & to its site. • Impacted foreign bodies and gas in gall stone ileus may also be visible in radiographs.
GAS FILLED LOOPS MULTIPLE FLUID LEVELS
PRINCIPLES OF TREATMENT OF ACUTE INTESTINAL OBSTRUCTION • GASTROINTESTINAL DRAINAGE • FLUID & ELECTROLYTE REPLACEMENT • RELIEF OF OBSTRUCTION
SUPPORTIVE MANAGEMENT • NASOGASTRIC DECOMPRESSION 4th hourly aspiration by Ryle’s or Salem tube.
REPLACEMENT OF SODIUM AND WATER LOSS with Hartmann’s solution or normal saline.The volume required is determined by clinical, haematological & biochemical criteria. • ANTIBIOTICS
SURGICAL TREATMENT INDICATIONS OF EARLY OPERATION • Obstructed or strangulated external hernia • Internal intestinal strangulation • Acute obstruction
OPERATIVE ASSESSMENT • SITE OF OBSTRUCTION • NATURE OF THE OBSTRUCTION • VIABILITY OF THE GUT
PRINCIPLES OF SURGICAL INTERVENTION • MANAGEMENT OF SEGMENT AT SITE OF OBSTRUCTION • DISTENDED PROXIMAL BOWEL • UNDERLYING CAUSE OF OBSTRUCTION
STEPS OF SURGICAL PROCEDURES • Identification & assessment of the caecum. Collapse indicates small bowel obstruction. • Display the cause of obstruction by careful retrograde assessment. • Operative decompression may be performed
Depending upon the nature of cause, enterolysis, excision, bypass or proximal decompression can be performed. • Following relief of obstruction, viability of the involved bowel should be assessed
OBSTRUCTION BY ADHESIONS & BANDS • Most common cause of intestinal obstruction • Peritoneal irritationlocal fibrin productionadhesions between apposed surfaces
ADHESIONS • Classified into early or late • Usually involves the lower small bowel • Appendicitis & gynecological procedures are common precursors
SBO from adhesions. Note fixed loop of small bowel in right pelvis (arrow) that doesn’t change position with different patient position – suggests adhesion.
Ischemic areas Foreign material Infection Inflammation Radiation enteritis drugs Sites of anastomosis Reperitonealisation of raw areas Trauma& vascular occlusion Talc,starch,gauze,silk Peritonitis,TB Crohns practolol COMMON CAUSES
BANDS • Congenital • String band following bacterial peritonitis • portion of greater omentum adherent to parietal • TREATMENTconservative upto 72 hours,laprotomy& release of band obstructions
TREATMENT OF RECURRENT INTESTINAL OBSTRUCTINS DUE TO ADHESIONS • REPEAT ENTEROLYSIS ALONE • NOBLES PLICATION OPERATION • CHARLES-PHILIPS TRANS MESENTERIC PLICATION • INTESTINAL INTUBATION
INTESTINAL NOBLES PLICATION CHARLES PHILIPPS INTUBATION PROCEDURE
POST OPERATIVE INTESTINAL OBSTRUCTION • Usually incomplete obstruction • Early post op obstruction(1-5days) non strangulating causes, majority settle with continued conservative management • Late post-op obstruction(>7days) surgical intervention is required
SPECIAL TYPES OF MECHANICAL OBSTRUCTIONS
INTERNAL HERNIA SITES OF NITERNAL HERNIA • foramen of winslow • hole in the mesentery • hole in the transverse colon • defects in the broad ligament • congenital or acquired diaphragmatic hernias, • duodenal retro perironeal fossae • caecal/ appendiceal retroperitoneal fossae • Inter sigmoid fossa
OBSTRUCTION FROM ENTERIC STRICTURES • Occurs secondary to TB or Crohn’s disease • Malignant strictureslymphoma • Presentation is sub a/c or c/c • Standard surgical management is resection& anastomosis • Strictureplasty for Crohn’s
BOLUS OBSTRUCTION • FOOD • GALL STONES • TRICHO BEZOARS • PHYTO BEZOARS • STERCOLITHS • WORMS
TRICHO BEZOAR STERCOLITH FABRIC BEZOAR
ACUTE INTUSSUSCEPTION • occurs most commonly in children, in an idiopathic form peak incidence at 3—9 months. • hyperplasia of Peyer’s patches in the terminal ileum may be the initiating event secondary to weaning. adenovirus or rotavirusis also assosciated.