Lecture 5/6: Sx of the Intestines

What is an incision into the intestine?

enterotomy

What is removal of a segment of the intestines?

enterostomy

What intestinal resection and anstomosis?

an enterostomy with reestablishment of continuity between the divided ends

What is surgical fixation of one intestinal segment to another?

intestinal plication (aka an enteroenteropexy)

What is an enteropexy?

fixation of an intestinal segment to the body wall or another loop of intestine

surgical fixation of the colon

colopexy

partial or complete resection of the colon

colectomy

typhlectomy

resection of the cecum

colostomy

surgical creation of an opening between the colon and the surface of the body

tenesmus

straining to defecate

dyschezia

pain or discomfort on defecation

hematochezia

passage of stools that contain red blood

melena

passage of tarry stools (digested blood)

What are the common indications for sx of the small intestines?

• GI obstruction: tumors, intussusception, FBs, masses

• Trauma: perforation, ischemia

• malpositioning

• trauma

• diagnostic/supportive procedures: biopsy, culture, cytology, feeding tubes

What are the common indications for sx of the large intestines?

• obstruction: tumors, intussusception, granulomatous masses

• perforation

• colonic inertia

• chronic inflammation

What can information about small intestines can visual examination provide?

• mental status

• temperament

• nutritional state

• comfort

What can information about small intestines can visual abdominal palpation provide?

• pain

• thickened intestine

• abdominal masses

• mispositioned organs

What portions of the large intestines are normally palpable?

• colon (dorsocaudal abdomen)

• feces or masses

• sublumbar LN enlargement may be palpable

What are you evaluating for during a SA rectal exam?

• Shape & symmetry of pelvis

• Mucosal thickness

• Pelvic canal masses

• Intraluminal masses

• Distal strictures

What pre-op steps should be taken before intestinal surgery?

• minimum database BW

• localize lesions with diagnostics

• correct abnormalities

• transfuse if necessary

• withhold food

• administer prophylactic antibiotics if necessary

What systemic diseases need to be identified before small intestinal surgery?

• Renal Disease

• Hepatic Disease

• Hypoadrenocorticism

• Hypercalcemia

• Diabetes Mellitus

• Pancreatitis

True or false: most animals with large bowel disease have no laboratory abnormalities.

true

What can contrast studies show in the SI?

• Foreign bodies

• Obstructions

• Abnormal displacements

• Abnormal bowel wall thickness

• Irregular mucosal pattern

• Distortion of the bowel wall

Why is abdominal ultrasound typically done before contrast studies?

it often provides the diagnosis and allows the contrast study to be circumvented

What type of masses may be identified if colon contains gas?

luminal

What does a coiled spring appearance (with gas or barium) indicated in LI?

cecal inversion or intussusception

What have been replaced by colonoscopies?

barium enemas

What is the preferred intestinal imaging modality?

ultrasonography

What allows visualization and biopsy of the duodenum?

gastroduodenoscopy

What allows visualization and biopsy of the ileum?

colonoileoscopy

Visualization of intestinal mucosa may detect ______ that is not detected with radiographs or ultrasound.

ulcers, erosions, infiltrated mucosa and/or lymphangiectasia

What is endoscopy and colonoscopy more sensitive for than radiology?

• masses

• ulcers

• infiltrates

• intussusceptions

The benefits of stabilizing the animal’s condition before surgery must be weighed against:

• risk of ischemic necrosis

• risk/presence of septic abdomen

What contians more bacteria than the rest of the GI tract?

colon

What pre-op management step is unique to the colon?

emptying and cleansing indicated to reduce bacterial load, unless perforation or obstruction suspected

What is an elemental diet?

a diet that proposes the ingestion, or in more severe cases use of a gastric feeding tube or intravenous feeding, of liquid nutrients in an easily assimilated form. It is usually composed of amino acids, fats, sugars, vitamins, and minerals

What is given 24 hours prior to LI surgery?

• laxatives

• cathartics

• warm water enemas

An electrolyte solution + enema is the best for cleansing the colon. When are electrolyte solutions contraindicated?

with obstruction

What negative effect can enemas have if given any closer to surgery than 3 hours pre-op?

may liquefy intestinal content and add to the dissemination of contaminated material during surgery

What type of enema should never be given to small or constipated patients?

hypertonic phosphate

What are the negatives of pre-op enemas?

• enemas can further deteriorate debilitated, anorectic patients

• may cause colonic perforation

• may be ineffective in cats with megacolon

What are operative wounds in which the respiratory, gastrointestinal, or genitourinary tract is entered under controlled conditions without unusual contamination or without significant spillage of contents?

clean-contaminated wounds

What are open, fresh, accidental wounds; procedures in which gastrointestinal contents or infected urine is spilled or a major break in aseptic technique occurs?

contaminated wounds

When are SI prophylactic antibiotics indicated?

• In animals with intestinal obstruction because there is an increased risk of contamination associated with bacterial overgrowth

• When devascularized and traumatized tissue is present

• When surgery is expected to last longer than 2 to 3 hours

True or false: the risk of infection after colorectal surgery is low.

false

What type of antibiotics should be given for LI surgery?

systemic perioperative abx effective against anaerobes and gram (-) aerobes

What type of suture should be used for intestinal surgery?

monofilament, synthetic absorbable suture such as polydioxanone (PDS), polyglyconate, poliglecaprone (monocryl)

What type of needle should be used for intestinal surgery?

swaged-on taper or taper-cut point needle

What does optimal healing after intestinal surgery require?

• good blood supply

• accurate mucosal apposition

• minimal surgical trauma

What intestinal layer provides mechanical strength?

submucosa

What approximating suture patterns are used in intestinal surgery?

• simple interrupted

• gambee

• simple continuous

• stapling techniques feasible

What should intestinal surgical sites be covered with?

omentum or serosal patch

What should be done before closing the abdomen during intestinal surgery?

replace contaminated instruments and gloves

What are the measurements for an approximating suture closure of the intestine?

place simple interrupted sutures 2 mm from the edge and 2-3 mm apart - engage slightly more serosa than mucosa to force everted mucosa back into the lumen

What suture pattern is this?

gambee

What are the advantages to enterotomy for biopsies?

• Allows access to the entire GI tract

• Provides full-thickness biopsies

• Can examine and sample the rest of the abdomen at the same time

What are the disadvantages to enterotomy for biopsies?

• Most expensive and most invasive technique

• Does not allow one to detect mucosal lesions

• Does not allow one to obtain as many mucosal samples as flexible endoscopy

• It is possible to take nondiagnostic tissue samples if proper technique is not followed

How is an intestinal biopsy performed?

1. occlude lumen, make stab incision into lumen with No. 11 blade

2. remove 2-3 mm ellipse of tissue with metzenbaum scissors

3. make second incision approx parallel to the first with a scalpel

4. clos incision with simple interrupted sutures

How is an enterotomy closed?

• may be closed transversely if the intestinal lumen is small

• join extremes of longitudinal incision with simple interrupted suture to transpose the incision to a transverse orientation

• place remaining sutures 2 to 3 mm apart

How can you leak test enterotomy site?

syringe with sterile fluid

How is SI resection and anastomosis performed?

1. place forceps transversely across dilated proximal intestine and obliquely across the distal intestine

2. ligate vessels as indicated

3. transect intestine and mesentery where dashed lines indicate

4. place first suture at mesenteric border and second at anti-mesenteric border

5. place additional simple interrupted sutures to complete the anastomosis - appose mesentery in simple continuous pattern

How is an end-to-end anastomosis using a modified simple continuous pattern performed?

1. place and tie appositional sutures at mesenteric and anti-mesenteric borders, leaving the needles attached

2. using suture tags as stay sutures to maintain tension, place continuous suture pattern between anti-mesenteric and mesenteric sutures

3. reposition intestine and begin a second continuous suture line on the opposite side

What are the benefits of stapled anastomosis techniques?

• Less tissue reaction

• More mature fibrous connective tissue

• Greater tensile strength

• Fewer mucoceles

• Fewer necrotic areas

• Less luminal stenosis

What are the four stapled anastomosis techniques?

1. Triangulating End-to-End Anastomosis

2. Inverting End-to-End Anastomosis

3. Side-to-side or Functional End-to-End

4. End-to-side Anastomosis

How is a triangulating end-to-end anastomosis performed?

1. place 3 stay sutures that appose the ends of the intestine, and divide the circumference into 3 equal parts

2. apply tension between 2 of the sutures, fire the stapler, leaving a double staggered row of sutures

3. apply tension between next 2 sutures and position stapler to it overlies the end of the first row of staples and fire again

4. steps repeated a third time to complete anastomosis

How is an inverting end-to-end anastomosis performed?

1. Use an end-to-end anastomosis stapler and a transverse stapler.

2. Insert the stapler cartridge into the intestinal lumen through an enterotomy 3 to 4 cm from the transection site.

3. Insert the anvil into the other intestinal end.

4. Tie purse-string sutures securely around the shaft of the stapler.

5. After completing the anastomosis, close the enterotomy with sutures or a transverse stapler

What is this stapler?

reloadable GIA 60 stapling device

side-to-side or functional end-to-end

(putting on the pants, putting on the belt)

What is the telescoping or invagination of one intestinal segment (intussusceptum) into the lumen of an adjacent segment (intussuscipiens)?

intussusception

What are the most common areas of intussusceptions?

ileocolic and jejunojejunal

True or false: the cause of most intussusceptions is unknown.

true

What is the presence of an intussusception in a cat more likely associated with than in dogs?

neoplasia

What are the major causes of protein-losing enteropathies in young dogs?

intussusception and parasites

How do intussusceptions appear on ultrasound?

target or bull’s eye pattern (concentric intestinal alyers)

What prevents recurrence of intussusception?

enteroenteropexy

How is an intussusception reduced?

place traction on neck as you milk the apex out of the intussuscipiens

What is the major concern when performing colonic surgery?

blood supply

How do you reduce colonic bacterial numbers?

by eliminating oral intake preparing the colon, and giving antibiotics

True or false: dehiscence is more likely with large bowel sx than small bowel.

true

Why is a colopexy typically performed

• to create permanent adhesions between serosal surface of colon and abdominal wall

• to prevent causal movement of the colon and rectum

• to treat chronic recurring rectal prolapse

What is the typical complication of a colopexy?

infection resulting from suture penetration of the colonic lumen

What is the technique for a colopexy?

1. locate and isolate descending colon

2. pull colon cranially to reduce prolapse

3. verify reduction by nonsterile assistant

4. make 3-5 cm longitudinal incision through only serosal and muscular layers along the antimesenteric border of descending colon

5. make similar incision in left abdominal wall several cm lateral to linea alba through peritoneum and underlying muscle

6. complete pexy with simple continuous pattern of 2-0 or 3-0 monofilament absorbable suture

7. lavage surgical site

8. wrap with omentum before closing

What procedure is being performed here?

colopexy

What are colectomy and resection primarily used for?

colonic mass removal and megacolon

What percent of the colon can be resected in animals without adverse side effects?

70%

True or false: dogs tolerate colonic resection better than cats.

false

What should the owners be warned about after a subtotal colectomy in a cat?

the cat will probably defecate frequently and have soft stools

Why should the colonic lumen be occluded at both ends?

to minimize fecal contamination

During a colonic anastomosis, why should a needle be angled so that slightly more serosa than mucosa is engaged?

to prevent mucosa from protruding between sutures

What should be done if there are minor disparities between lumen sizes?

space sutures around the larger lumen slightly further apart than the sutures in the segment with the smaller lumen

When should a two-layered anastomosis be performed?

if there is tension at he anastomotic site

What are the two layers of a two-layered anastomosis?

• first layer of simple interrupted sutures is placed to appose the mucosa and submucosa, and the knots are tied within the lumen

• the second layer of interrupted sutures apposes the muscularis and serosa, and the knots are positioned extraluminally

The distal colon may be anastomosed to:

ileum or jejunum

What are the indications for a typhlectomy (cecal resection)?

• impacted cecum

• inverted cecum

• perforated cecum

• neoplastic cecum

How is a typhlectomy performed?

• double ligate cecal branches of ileocolic vessels

• dissect the ileocecal fold of mesentery

• place clamp across base of cecum near the cecocolic orifice and transect

• close colonic defect with simple interrupted sutures

Why is a typhlectomy indicated for this animal?

cecum inverted into colonic lumen

What is megacolon?

persistent increased large intestinal diameter and hypomotility associated with severe constipation

What is the difference between constipation and obstipation?

• Constipation – difficult or infrequent defecation with passage of unduly hard, dry fecal material

• Obstipation – extreme constipation (no feces may be passed)

What species is megacolon most common in?

cats

What measurement determines megacolon in cats?

diameter of colon is greater than 1.5 x length of L7