E2: Intestinal surgery (incl rectum and anus) Flashcards
What suture pattern(s) or closure techniques is/are most commonly used in intestinal surgery?
Appositional (simple interupted or simple continuous)
Modified Gambee (to help w/everted mucosa)
Using monofilament absorbable suture w/tapered needle
Stapling devices
Holding layer = SUBMUCOSA (so always incorporate), when in doubt go full thickness
When a mechanical obstruction of the intestinal lumen occurs, secretions from the bowel wall _____ and absorption across the bowel wall ______.
Increases
Decreases
(Dilation/Compression?) occurs proximal to an obstruction.
Dilation
What are the clinical and radiographic signs of linear foreign body?
Clinical: Vomiting, depression, abdominal pain, palpable BUNCHING of intestines in central abdomen (occurs when foreign body becomes fixed at some point cranially, typically around tongue or at pylorus)
Rads: Pilcation, Bunching, comma-shaped gas bubbles, could have no obvious lesions (esp cats)
How does the pathophysiology of linear and non-linear FBs differ?
Linear FBs cause obstruction due to peristaltic waves attempting to advance the object resulting in the intestines gathering around it (bunching, plicating). Continues peristalsis may cause cuts to the mucosa, lacerations to the mesenteric border of the intestines and result in peritonitis. Multiple performations can occur as can concurrent intissesceptions.
Non-linear FBs also cause complete or partial obstructions however the obstruction is due to the foreign body itself. Large FBs apply pressure and can cause venous stasis and edema, followed by arterial flow compromise, ulceration, necrosis and perforation.
How are linear foreign bodies managed surgically?
May require gastrotomy and multiple enterotomies
What are potential short and longterm complications of linear foreign bodies?
Inflammatory changes can impare intestinal function
Extensive resections(>70-80% removal) can cause Short Bowel syndrome - weightloss, diarrhea, malnutrition
Risk of anastomotic leakage (esp if also hypoALB)
Poor surgical technique can result in intestinal necrosis, perforation, leakgae dehiscence, peritonitis, endotoxic shock, and/or stenosis
What are some characterstic radiographic findings of non-linear FBs? (how would you differentiate a functional from an anatomic ileus?)
Radiolucent objects often surrounded by gas
Obstructed loops often become distended with air, fluid and/or ingesta
Anatomic ileus: Stacking of distended loops, Sharp turns/bends in dilated intestine, stacking
What is an intussusception and what are the parts called? Where do they occur most commonly?
Definition: telescoping or invagination of one intestinal segment (intussusceptum) into the lumen of an adjacent segment (intussuscipiens)
Occur most commonly ileocolic, jejuno-jejunal, and cecum
What is the typical signalment for an intussusception?
Young puppies
(with acute episode of enteritits, e.g. due to parvo) has peristent diarrhea
What is intestinal enteroplication? What are advantages and disadvantages of this procedure?
Aka Enteroenteropexy- surgical fixation of one intestinal segment to another
Advantages: Even if can manually reduce intussesception should do this to prevent recurrence
Disadvantages: Can cause obstruction, strangulaton, perforation
Where in the GIT is intestinal neoplsia most common in dogs? Cats?
Which tumors are common in dogs? Cats?
Dogs: Colorectal
- Leiomyoma/sarcoma (GIST- gastrointestinal stomal tumors)
- Adenocarcinoma
- Lymphosarcoma
Cats: Small intestine
- Duodenal polyps
- Adenocarcinoma
- Lymphosarcoma
How can viability of the intestine be assessed? What is the most reliable physical criterion?
Most reliable: PulsOx
Intestinal color (pink/red rather than blue/black)
Wall texture
Peristalsis
Pulsation of arteries
Bleeding when incised
Doppler
Fluoroscein stain (good accuracy for non-viable)
- Electromyography*
- Radioactive microspheres*
- Microtemperature probes*
- pH measurement*
How is fluroscein infusion used to determine intestinal viability?
Injected IV
Let equilibrate 2-3 min
View intestine w/Wood’s lamp
Viable= smooth, uniform, green-gold color or finely mottled pattern (no areas of non-fluorescence >3mm diameter)
This is a test for VASCULARITY/perfusion and is used to predict viability
Better for determining non-viable tissue - 95% accurate
How is surface oximetry used to determine intestinal viability?
Compare PulseOx reader (placed on intestinal wall) wit peripheral O2 saturation
Normal intestine remians within 1cm of normal PulsOx reading
Releable, reproducable means of assessing arterial perfusion or ischemia
What are the major principles of performing intestinal surgery (important precautions, materials
Minimize contamination: pack-off affected area with lap sponges, use a separate pack for the intestinal procedure (s)
Be gentle: occlude vessels with intesitnal forceps (Doyen) or fingers
Decompress dilated bowel loops
What must you do before cutting or clamping any bowel?
Determine extent of excision
Ligate blood supply (leave 2 ligatures in body and one on what you are removing) - to prevent back-bleeding
What is the advantage and disdvantage of using either a sclapel or scissors to divide the intestine?
Scissors: more control, more traumatic
Scalpel: less control, less traumatic
Why must you try to minimize mucosal eversion when doing an anastomosis?
Eversion increases risk of infection and adhesion formation.
Why should you angle your cut when performing an end-to-end anastomosis?
It enlarges the lumen size initially which accounts for the 10-20% narrowing that typically occurs during healing
When performing an intestinal anastomosis, where do you begin your closure? Why? What is the next thorw you place and then how do you close?
At the mesenteric border
Leakage is most common at this site (no serosa)
Fat in the mesentery impairs visualization
Next bite at anti-mesenteric border
Then close with simple continuous pattern (3-4mm apart and 3-4mm bites)
Use mosquitos to check tightness
How is a leak test performed for an anastomosis?
Occlude using Doyens (or fingers) proximally and distally
Inject sterile saline a few cm away from closure (6-8mL)
Compress and look for leakage
While skin staples can be used to close an anastomosis, what risk is increased? What is an advantage?
Mucosal eversion (less accurate/precise apposition)
Speed
How can disparity in lumen size be managed when performing an intestinal anastomosis (3 methods)?
- Angle your cut on smaller side
- Make incision on antimesenteric border (Fishmouth/Cheattle incision)
- Place mesenteric and antimesenteric sutures to stretch the smaller segment
After lavaging your closure, what can you do to protect the site as well as improving vascular and lymphatic supply?
Wrapping with omentum
When would you perform a serosal patch after an anatomosis or closure? What does this patch create?
When omentum is not avalable
To reinforce suture lines of questionable tissue
To reinforce an area that may be/seem unstable (e.g. diseases intestine that you can’t remove)
Creates a permanent adhesion much stonger than omentum