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
Describe the pathophysiology, signs and management of Short Bowel Syndrome.
Pathophys: Resection of so much intestine that the body cannot compensate without parenteral/enteral nutritional therapy (usually >70-80% of SI)
CS: Weightloss, diarrhea, malnutrition
Tx: Based on severity; correct hydration and e-lyte imbalances, provide adequate nutrition* (enteral, parenteral), control diarrhea (e.g. Famotidine + Loperamide), control intestinal bacterial population (e.g. Tylosin, Metronidazole + Enrofloxacin), growth factors (to facilitate intestinal adaptation and minimize CS)
*most important!
Which heals faster, small or large intestines?
Small intestines
A(n) _______ is an incision into the small intestines while a(n) _______ is an incision into the large intestines.
Enterotomy
Colotomy
What surgery would be indicated for recurrent rectal prolapse or recurrent perianal hernia?
Colopexy
What are the causes of megacolon?
Idiopathic (most common cause in cats)
Neurologic (e.g. Lumbosacral disease, aganglionic distal colonic segment)
Mechanical or functional colonic obstruction (e.g. pelvic trauma, adesions from OVH)
Self-induced impaction (E.g. too painful to poop due to fistula)
Congenital
What defect is associated with idiopathic megacolon in cats?
Generalized dysfunction of colonic smooth muscle that involves the activation of smooth muscle myofilaments
Which species is more commonly diagnosed with megacolon?
Cats
What are the treatment options for megacolon?
Surgical disssection and removal
Potential resection and anastomosis
Medical management: Diet (low residue), keep well hydrated, edemas/deobstipation, prokinetic drugs (Cisapride), stool softeners (Lactulose)
What are the goals of subtotal colectomy in the management of idiopathic megacolon?
Alleviate the clinical signs of the disease
Remove as much affected colon as possible
T/F: Ileocecal valve preservation in cats with idiopathic megacolon has no real clinical benefit.
True
Which type of subtotal colectomy/anastomosis, colecolonic or ileocolonic, allows you to remove more colon? Which one involves greater tension?
Ileocolonic= can remove more colon
Colecolonic= more tension
Wha are expected clinical signs after subtotal colectomy? What is the post-op course/plan?
+/- Tenesmus q7 days
Diarrhea, soft stool for weeks
Increased frequency of defecation
Post-op: Offer food and water ASAP (within 12 hours) and taper fluids and e-lytes as oral intake normalizes, pain management
What complications can occur after intestinal surgery?
Most complications occur in first 3-5days post-op
Dehiscence, leakage: if low ALB increased risk(pre-op ALB <2 = higher potential), monitor CBC for bands (indicating leakage),
Ileus
Adhesions
Obstruction
Peritonitis
Short Bowel Syndrome
What are some situations in which the benefits of stabilizing the patient before surgery outway the risks?
- Penetrating abdominal injury
- Large numbers of neutrophils (>25k) or very toxic neutrophils ID’d on cytology of effision
- Bacteria in the effusion
- Blood-to-peritoneal fluid Glucose difference >20mg/dl
- Peritoneal fluid [lactate] >2.5-5.5 mmol.L
- Extraluminal gas bubbles or Volvulus ID’d on imaging
- Esophageal or gastric intussesception
- Bacterial culture of fluid is positive for pathologic bateria
List the different intestinal biopsy techniques with advantages and disadvantages of each?
Logitudinal BX w/longitudinal or transverse closure
Transverse wedge BX (wedge <20-25% circumference)
Dermal punch
Laproscopic (minimally invasive)
What is a cecal inversion? What are the typical clinical signs? What is the treatment?
Cecal intussusception
CS: Chronic diarrhea with hematochezia
Tx: Typhlectomy (removal of cecal- Standard), can attempt manual reduction or explose through colotomy
What is the “Poster Child” for mesenteric volvulus? What are the CS?
German Shepherd (large breed dogs)
CS: similar to GDV, acute abdominal distension, pain, vomiting, shock, nonresponsive orogastric intubation
What is the treatment and prognosis of mesenteric torsion?
Tx: Rapid fluid resuscitation and immediate abdominal exploration- derotation +/- resection and anastomosis
Problem: Reperfusion injury pretty much inevitable
Prognosis: Better for segmental (which doesn’t need to be derotated)
What is the most common cecal tumor? Treatment?
Cecal leiomyosarcoma
(also, most common site for this tumor)
Tx: Typhlectomy
What are the risk factors for dehiscence after intestinal surgery? What is the overall dehiscence rate? What is the mortality rate when dehiscence occurs?
Pre-op albumin <2g/dL (risk leakage)
Pre-op peritonitis
Post-op rise in band neutrophils
Foreign bodies, trauma
Overall dehiscence: 7-15%
Mortality: 74-85%
What are the predisposing factors for rectal prolapse?
Tenesmus
Rectalanal disease
Urogenital disease
How do you differentiate between a rectal prolapse and an intussusception?
Probe test: pass between border of anus and protruding mass; if can pass probe then it is intussusception
What is the treatment for rectal prolapse?
ID and treat underlying cause
If viable: Reduce and place purse-string suture, maintain for 3 days
If not viable: Amputate
If recurrent: Colopexy
How are rectal tumors diagnosed? What do you do after you diagnose one?
Direct visualization
Palpation on rectal
Proctoscopy/colonoscopy
Either remove or biospy
What are the treatment options for rectal tumors?
Surgical exicison: Transanal or Dorsal approach
Mucosal resection
Cryosurgery
Why should the whole colon be evaluated when you suspect a colorectal adenocarcinoma? How would you do this?
50% are abdominal
May be multiple
Via Colonoscopy
When would you use an anal/transrectal approach for a tumor? Dorsal approach? When would you do a rectal pull-through?
Anal/Transrectal: if involving caudal rectum or anal canal
Dorsal: if involving midrectum, not anal canal
Pull-through: when distal colonic or midrectal lesion is not approachable through abdomen
Describe the surgical management of anal sacculitis.
Anal sacculectomy: esp for recurrent infectons; wait until inflammation in surrounding tissue resolves - Medical therapy; closed or open technique
Closed: Balloon/Foley catheter or paraffin injection as guide, push external sphincter muscle out of the way
Open: Through duct, cut external sphincter muscle (incontinence more likely)
Within which muscle to the anal sacs lie?
External anal sphincter muscle
If you are removing a tumor of the anal sac, would you use an open or closed surgical technique?
Closed
To prevent tumor seeding into surrounding tissue
Why could a draining tract form after an anal sacculectomy? What do you do about that?
Incomplete removal of sac
Must excise
What type of perianal gland tumor is more common in male intact dogs?
Adenomas
What is the most common malignant tumor of the anal sac? What is the typical appearance of this tumor? What are the paraneoplastic syndromes that is commonly caused by this tumor and what are the clinical signs?
Apocrine gland adenocarcinoma
Multiple perianal masses around the anus in the hairless area (may vary in size, could be covered in epithelium or ulcerated, friable and broad based)
Most are invasive (while adenomas tend to be well circumscribed)
PNS: Hypercalcemia of malignancy and Renal dysfunction
CS: anorexia, weight loss, vomiting, PUPD, muscle weakness, constipation
To which lymph nodes do perianal adenocarcinomas tend to metastasize?
Sublumbar lymph nodes
What is/are chronically relapsing suppurative, progressive, deep ulcerating tracts in the perianal tissues called? In what breed of dog do they common occur and what is a likely etiology?
Perianal fistulae
German Shepherd
Immune-mediated
What is the recommended management for perianal fistulae?
Medical mgmt
Diet
Cyclosporin
+/- Ketoconazole, glucorticoids, tacrolimus (topical), azothioprine, metronidazole
T/F: Fistulae first appear as small, draining holes in perianal skin that is inflamed and hyperpigmented
True
Note- hyperpigmentation
What are the management options for perianal gland adenoma?
Shrink with short course of Diethylstildestrol (DES)
Castration +/- resection of mass (some adenomas regress completely after castration)
(If large, biopsy is indicated)
What is going on in this picture (note that the ventral aspect of the anus is incomplete)? What can this anomaly cause?
Anogenital cleft
Fecal incontinence, soiling of the perineum, and perineal irritation
Also, ascending infections, pylonephritis
