Intestinal Surgery and Perineal Surgery

Question 1

Which is the suture holding layer in intestinal surgeries? which suture material and size are we using?

Answer 1

• Submucosa is the holding layer
• Monofilament absorbable suture (closing the intestinal layer 4/0 PDS for dogs and 5/0 PDS for cats)

-> Closure: Simple interrupted full thickness suture (identifying the layers is crucial to avoid failure as the submucosal layer has to be engaged! - take wide bite on serosa and muscularis and take less of mucosa (making a V) to push mucosa back in

Question 2

Which intestinal obstructions are common in young vs old dogs?

Answer 2

Young: FB, intussusception
Old: FB, Neoplasia/intussusception

Question 3

In which parts of the GI tract do FB usually lodge?

Answer 3

Jejunum or ileocaecolic junction (pressure necrosis)

Linear FB are usually fixed at the tongue or pylorus (plication, mesenteric tension, perforation)

Question 4

Where in the GI tract does intussusception usually occur and what causes it in young vs old dogs?

Answer 4

-> At the ileocolic junction
Generally occurs because GI tract too active

young dogs: parasitism, enteritis, caecal inversion

old dogs: neoplasia, other pathology

Question 5

How do we diagnose an intestinal obstruction?

Answer 5

• clinical signs suggestive
• clinical examination (abdominal palpation, check tongue)
• abdominal radiographs (repeat if non diagnostic at first)
• abdominal ultrasound
• CT (neoplasia)

Question 6

What needs to be prepared/considered for an intestinal surgery?

Answer 6

Clean-contaminated procedure
- pack off the area
- separate instruments into clean and dirty
- local lavage after procedure

Question 7

Which surgical procedure should be performed to remove a FB?

Answer 7

Enterotomy

Question 8

Where should the incision be made into the GI tract when removing a FB?

Answer 8

Milk the intestinal contents away from the proposed incision site - make the incision into the normal part of the bowel that isn’t too inflamed (aboral to where intestinal FB is)
-> Longitudinal incision on anti-mesenteric margin of intestine

Question 9

What do we do to test the closure after surgery of the small intestine? What does this evaluate?

Answer 9

Check closure by injecting sterile saline into intestinal lumen using 22g needle and syringe.

It does NOT evaluate if we engaged the submucosa or not. Simply assess suture spacing to make sure that they are close enough together to not have any leaks.

Question 10

Which suture material, size and pattern are we using when performing an intestinal resection and anastomosis closure?

Answer 10

Anastomosis closure: simple interrupted full thickness 3/0 to 4/0 monofilament absorbable (PDS). Work from mesenteric edge up either side.

Question 11

What are the postoperative considerations/treatments after performing an intestinal resection?

Answer 11

• Fluid support
• Feeding (as soon as possible - best prokinetic)
• Promotility agents (metoclopramide, erythromycin)
• Gastroprotectants (pantoprazole)
• Anti-emetics (maropitant)
• Analgesia (buprenorphine - side effects not as strong. Don’t go overboard with other stronger opioids as it can contribute to ileus, such as methadone or fentanyl)

Question 12

What can be done during surgery to avoid intussusception from re-occurring?

Answer 12

• Plication of the small intestine
• Suture transverse colin to stomach

Question 13

How do we assess if a dog has a prolapsed intussusception or a rectal prolapse?

Answer 13

Passing a probe, if it is intussusception the probe can be inserted further. If it is a prolapse probe won’t go in as far into rectum.

Question 14

What is the difference between primary and secondary obstipation? And what are the common causes of obstipation?

Answer 14

Obstipation = constipated to a point where the animal becomes non-manageable

Primary: within
Secondary: external compression (pelvic fractures), obstruction (mass)

Common causes: perineal hernia, perianal fistulas, anal sac disease, pelvic trauma, rectal strictures (neoplasia), Idiopathic megacolon in cats

Question 15

What are the clinical signs and diagnosis of obstipation?

Answer 15

• weight loss, anorexia, abdominal pain, scant, thin faeces, blood in faeces, mucoid diarrhoea
• firm mass in abdomen (colon)
• haematologic changes of chronic disease (anaemia)

Diagnosis = clinical signs, rectal examination, radiographs, CT

Question 16

How do we surgically treat obstipation in cats but not in dogs?

Answer 16

Subtotal colectomy - cats do well with this procedure, dogs do not! (diarrhoea, bacterial overgrowth, electrolyte imbalances)

Question 17

Which preoperative antibiotics and analgesia should be given before performing a subtotal colectomy?

Answer 17

3rd generation cephalosporins
Morphine epidural

Question 18

In which dogs/cats are rectal prolapse more commonly seen?

Answer 18

• More common in young animals
• Naturally docked dogs and cats (brachycephalic dogs, minx cats)
• Secondary to persistent straining
• Older animals: neoplasia, traumatic/neurologic

Question 19

How do we treat a rectal prolapse?

Answer 19

-> Address inciting cause

-> Acute prolapse: conservative - lubricant, epidural (morphine), manual reduction, anocutaenous purse string for 4-5 days (tight), stool softener

-> Traumatised/nonviable prolapse: amputation

Question 20

When is a colopexy indicated? And what should be some postop considerations?

Answer 20

Indicated for extensive or repeated prolapse (after conservative treatment)

• Stool softeners, epidural (straining), E collar, avoid rectal manipulation, address inciting cause (young animals - worms or some degree of enteritis)

Question 21

What are some rectal primary tumours that can occur in dogs and cats?

Answer 21

Dog: adenoma, adenocarcinoma, lymphosarcoma, leiomyosarcoma, leiomyoma

Cat: adenocarcinoma, lymphosarcoma, leiomyosarcoma
(almost always malignant in cat)

Question 22

What are the clinical signs/clinical findings with colorectal neoplasia?

Answer 22

haematochezia (blood in faeces), tenesmus (straining to pass stool), rectal prolapse, rectal bleeding independent of defecation

-> Mass palpable on rectal palpation - differentiate between luminal/intraluminal/extramural lesion

Question 23

What are the perioperative considerations of perineal surgery?

Answer 23

-> Bowel preparation - trying to empty out colon before surgery is sometimes contraindicated. Rather do a purse string suture.

-> Antibiotics: gram negative bacteria predominating in this area (3rd gen cephalosporin)

-> Do an exit culture after surgery just in case it is needed for AB selection

Question 24

Which analgesics are important to consider for a perineal surgery?

Answer 24

Epidural analgesia:
- intraoperative relaxation
- postoperative analgesia
- reduces straining
-> Morphine (up to 24 h)
-> +/- Bupivacaine (1-6 hours)/lidocaine

Question 25

Are perineal hernias more common in male or female dogs? Which breeds?

Answer 25

-> male (older intact - testosterone linked)!
- poodles, maltese, yorkies, collies, boxers

occasionally females (geriatric or traumatic)

In cats: megacolon

Question 26

Other than being an older male intact dog, which other condition in these dogs might be linked to a perineal hernia?

Answer 26

Prostatomegaly

Question 27

When surgically repairing a perineal hernia, which other procedure should always be done at the same time to reduce the recurrence?

Answer 27

castration

Question 28

What is the history/clinical signs of a dog with a perineal hernia?

Answer 28

• Tenesmus, constipation
• Perineal swelling
• Anuria, stranguria, vomiting

Question 29

What would be the clinical findings/how do we diagnose a perineal hernia?

Answer 29

• Perineal swelling
• Rectal dilation/deviation
• Do a rectal examination - bilateral vs unilateral - wouldn’t feel any muscular support on examination
• Do an abdominal ultrasound/radiograph to see how big the prostate is, also assess bladder & location (urinary bladder retroflexion)
• Haematology and serum chemistry (indicated in older dogs or when bladder retroflexion expected - could have post renal azotaemia

Question 30

What are some associated lesions in older intact male dogs that present with a perineal hernia?

Answer 30

• Prostatic disease
• Urinary bladder retroflexion
• Old male dog disease: perineal adenomas, testicular neoplasia

Question 31

How can we surgically repair a perineal hernia?

Answer 31

• Standard repair (trying to close the muscles, usually not indicated because there is usually not enough soft tissue to work with)
• Internal obturator flap (most commonly performed)
• Mesh
• Semitendinosus flap (more for the ventral component) usually combined with internal obturator flap
• Cystopexy (suturing bladder to side of body wall, prevent it from herniating back into the perineal hernia
• Ductus deferensopexy (reduces pressure), suture ductus deferens to side of body wall

Question 32

A dog presents with problems to their anal sacs - what could be some DDx? (anal sac diseases)

Answer 32

Impaction - ongoing anal sacculitis
Infection/Abscess
Neoplasia

Question 33

How do we treat an anal sac abscessation?

Answer 33

Conservative treatment: wound management, Antibiotics

Anal sacculectomy indicated if recurrence is an issue. ALWAYS do bilateral!

Question 34

How do we treat an anal sac abscessation with a rupture and draining wound?

Answer 34

• Treat conservative - antibiotics, E-collar
• Then remove anal sac when disease quiet
• Open draining tracts

Question 35

What are the important do’s and don’ts for performing an anal sacculectomy?

Answer 35

• Always bilateral even for neoplasia
• flush out then do exit culture
• leave skin in apposition, without suturing to let it heal by 2nd intention - allows it to constantly drain. Sutures not good as they are hard to remove if covered in faeces
• Send anal sacs for histopathology

Question 36

How do we diagnose anal sac neoplasia?

Answer 36

Physical exam
Cytology (FNA)

Evaluate regional lymph nodes with rectal exam, abdominal radiographs, ultrasound, CT

Question 37

How do we treat anal sac neoplasia?

Answer 37

• Surgical excision of anal sac and lymph node if involved
• Bilateral excision
• Closed technique! (get entire tumour)
• Adjunct therapy (radiation, chemotherapy)

Question 38

Which anal sac neoplasia does more commonly occur in older female dogs?

Answer 38

Perianal adenocarcinoma
- nodular diffuse lesions
- often ulcerated
- varying size, often multiple
- malignant
- paraneoplastic hypercalcaemia
- early metastasise