GI Surgery

Question 1

what perioperative antibiotic is used in all GI surgeries

Answer 1

cefazolin (high dose 1st generation cephalosporin)

used in simple GI sx:
- no septic abdomen
- no open bowel
- no spillage/perforation

Question 2

when should broad spectrum antibiotics be used in GI surgery

Answer 2

perioperative and postoperative for:
- septic abdomen
- GI perforation

empiric: ampicillin + fluoroquinolone
- switch to specific Ab once culture and sensitivity comes back

Question 3

what are the 4 criteria for assessing intestinal viability

Answer 3

1. color
   - pink, red, slightly purple
2. consistency
   - thick or normal (NOT thin)
3. motility
   - may or may not be motile
   - motile guarantees viability
4. bleeding/perfusion

Question 4

what layer of the GI wall must be perfused for the intestine to be viable

Answer 4

seromuscular layer
- must bleed when incised

mucosa can be poorly perfused and still have viable intestine - will slough off and regenerate eventually

Question 5

what is the holding layer in all GIT regions

Answer 5

submucosa

Question 6

what suture material should be used to close the GIT

Answer 6

absorbable monofilament
(PDS)

NEVER use cutting needles

Question 7

gastric closure

Answer 7

2 layers

1. mucosa + submucosa
   - simple interrupted or continuous
2. muscularis + serosa
   - inverted (lembert or Cushing)

Question 8

small and large intestine closure

Answer 8

1 layer appositional
- simple interrupted or continuous

MUST include the submucosa in the closure but does not need to be full thickness (does not need to include mucosa)
- can be full thickness if unsure

Question 9

characterstics of esophageal healing

Answer 9

SLOW due to:
- no serosa
- constant motion of the neck
- high tension area
- no omentum

Question 10

what approach is used for esophageal surgery

Answer 10

cervical - ventral midline
cranial thoracic - L or R thoracotomy
caudal thoracic - L 7-9th intercostal

Question 11

considerations for gastric surgery

Answer 11

• balfour retractors
• use packing to pad entire area
• stay sutures to elevate and manipulate stomach

can resect up to 75% of the stomach without affecting lumen size

Question 12

most common gastric neoplasia

Answer 12

gastric carcinoma

causes diffuse thickening of gastric wall (US) + severe, intractable vomiting

Question 13

what causes gastric ulceration

Answer 13

NSAID/corticosteroid use
hepatic disease
renal disease
neoplasia

Question 14

blood supply of the jejunum

Answer 14

vascular arcades - makes for natural breakpoints for resection

Question 15

duodenocolic ligament

Answer 15

located at the duodenal flexure where the descending duodenum turns into ascending duodenum

does NOT have substantial blood supply - can be incised

Question 16

indication for small intestinal biopsies

Answer 16

chronic enteropathies

goal: sample multiple sites of the SI using a punch biopsy or full thickness (if indicated)

Question 17

where should you incise into the intestine to remove a foreign body

Answer 17

aborad to the foreign body (healthy tissue)

orad segment will be inflammed/swollen

Question 18

intestinal resection & anastomosis considerations

Answer 18

always plot out where on the arcades to make ligatures to ensure remaining vessels are well supplied

crushing clamps - most important; placed over the point of resection to separate healthy tissue from nonvital

noncrushing clamps - functions to block the flow of GI contents; placed 1-2 mm from resection site on the part of the body remaining in the body

always ligate on BOTH sides of the crushing clamp

Question 19

how to handle luminal disparity during closure

Answer 19

place sutures on the large diameter segment at WIDER intervals and place sutures on the smaller diameter segment at NARROWER intervals

Question 20

intestinal anastomosis technique

Answer 20

place 3 stay sutures at the mesenteric border to prevent loss of visualization

use simple interrupted sutures around the diameter, placing the first at the bottom of the circumference and the second at the top to ensure adequate apposition

always close the mesenteric rent (hole created in mesentery)

Question 21

how to test the closure

Answer 21

pinch off segments orad and aborad to the anastamosis and inject saline to test for leakage

Question 22

technique for removing linear foreign bodies

Answer 22

1. remove the anchor at the tongue base or pylorus
2. gastrotomy +/- enterotomy - remove the foreign body
3. examine mesenteric border for perforations
4. resect areas of perforations
5. run the entire bowel to check for tension

Question 23

intussusception

Answer 23

telescoping of one part of the bowel into another

occurs in YOUNG dogs/cats with underlying enteropathy

occurs in OLD dogs/cats with neoplasia

Question 24

how to resolve intussuception

Answer 24

reduce the telescoping by milking the intussusceptum and pulling the intussuscipiens to remove

monitor for revascularization

Question 25

risks of recto-colonic surgery

Answer 25

dehiscence slower healing less reliable blood supply higher anaerobic bacterial load more tension

Question 26

vasa recta

Answer 26

many small vessels that branch off of the ileocolic and colic arteries to feed segments of the colon

Question 27

cranial rectal artery

Answer 27

branch of the caudal mesenteric artery that supplies the distal colon

Question 28

indications for colo-rectal resection

Answer 28

1. colonic neoplasia 2. feline megacolon 3. rectal neoplasia 4. colonic foreign bodies that do not pass

Question 29

are full thickness biopsies indicated in colon

Answer 29

NO - can get full diagnostics with a scope

Question 30

feline megacolon

Answer 30

idiopathic disturbance in the activation of smooth muscle myofilaments signs: - fecal tenesmus - pain defecating - vomiting - anorexia - dehydration

Question 31

feline megacolon dx and tx

Answer 31

dx: radiographs - colon distension and fecal impaction tx: subtotal colectomy - remove 95% of entire colon

Question 32

is rectal neoplasia more common in dogs or cats

Answer 32

dogs

Question 33

what is the most common rectal neoplasia in dogs

Answer 33

epithelial - polyps - carcinoma in situ - adenocarcinoma undergoes malignant transformation to gradually invade the wall

Question 34

diagnosis of rectal neoplasia

Answer 34

if superficial and coming out of the rectum: - FNA - core biopsy - incisional biopsy if proximal: - proctoscopy - colonoscopy

Question 35

mucosal eversion

Answer 35

retraction of the mucosal margins of the rectum using stay sutures used for noninvasive (polyps) and superficial (caudal 1/3 of rectum) masses

Question 36

indications for anal sacculectomy

Answer 36

1. anal sac neoplasia - non-elective 2. anal sacculitis, infection, impaction - elective

Question 37

what kind of neoplasia affects the anal sac

Answer 37

apocrine gland adenocarcinoma may need to do a lymphadenectomy as well

Question 38

technique for anal sacculectomy

Answer 38

closed approach - incise over the sac and dissect from the outside