Large Intestine SA Surgery Flashcards
(45 cards)
What defines the colon and rectum?
Section of LI in the abdomen (colon) and pelvis (rectum)
Give 3 surgical approaches to the colon
Ventral Midline Laparotomy
Pelvic Split
Transanal
What tool is used for a pelvic split? Where is the cut made?
Osteotome (small/young animals)
Saw
> cut pubic symphisis
When is colonotomy indicated? How is this carried out?
Rarely!
- If full thickness biopsy required
> principles same as enterotomy
Does a FB trapped in the colon require surgery?
No, milk FB out of anus
What can removal of the colon cause? How much can be removed before complications arise?
- Decreased colon length -> loss of reservoire and absoprtion capacity, so feaces ^ frequency and ^ wateryness
- <6cm in a labrador sized dog can be removed without faecal incontinence
What should always be preserved in a colon resection?
Ileoceacal junction - preserves ileal function to prevent retrograde flow of colonic bacteria -> SI (could -> bacterial overgrowth and chronic D+)
What is the name of the nerve bundle sitting on the wall of the rectum?
Pelvic plexus
What closure materials can be used for a LI anastomosis? What are the pros and cons of each?
> Sutures (single layer, simple, interrupted, appositional, PDS 2 monofilament) - optimise would healing, faster gain in tensile strength, minimise v in lumen diameter to v risk of stricture formation, fewer complications.
Staples - rapid and reliable, insert via rectum or incision in ceacum, provide inverted anastomosis, cause post-opbleeding (heals by itself), higher bursting pressures on d7 but no overall difference in healing
Give 7 post-op complications of colorectal surgery
- Would dehiscence and septic peritonitis
- Wound infection
- Abscess
- Faecal incontinence
- Stricture and tenesmus
- Rectal prolapse
- Haematochezia
How are ABs usually used? How does this differ in colorectal surgery?
Therapeutically (culture and sensitivity)
- In colorectal surgery used prophylactically to prevent contamination progressing to a full on infection
What is the most common cause of megacolon? What should first be ruled out?
1* idiopathic megacolon most common 2* causes should be ruled out first (usually problems resulting in constipation for >5m) - Pelvic Fx - Intrapelvic space occupying lesion (neoplasia, lymphadenopathy, abscess) - Colorectal neoplasia - Colorectal abscess - Perineal hernia (pelvic floor mm) - Innapropriate diet
Outline the clinical signs of megacolon
- chronic constipation
- tenesmus
- V+ if v long term
- anorexia
- weight loss
- large colon containing faecal material
- dehydration
- poor body condition
What should be the first option for megacolon Tx? What are the 2 main Tx options?
> Treat underlying 2* disease
- Medical management (evacuation of colon, laxatives, prokinetics, frequent walks, ^ fibre v residue diet)
- Surgery (subtotal coloctomy)
What are the post-op complications associated with subtotal colectomy? What is the prognosis?
- recurrent constipation
- ^ defeacation freqency
- soft watery feaces
- tenesmus
- rectal prolapse
> prognosis good
What % of colorectal neoplasia is malignant? Give examples of benign and malignant tumours.
50%
- Benign: Adenomatous polyps [~50% show malignant transformation], leiomyomas
- Malignant: Adenocarcinomas, leimyosarcoma, lymphoma, haemangiosarcoma (endothelial cells of BVs) plasmacytoma
Which artery should NOT be ligated when performing colorectal resection?
Caudal mesenteric - may appear small in the cat! Will remove entire blood supply to rectum. Always ligate close to rectum.
What signalment is over-represented for colorectal neoplasia?
- older dogs 6-9yo
- adenocarcinomas in GSD, Great Dane, Boxer, Doberman
What are the clinical signs of colorectal neoplasia?
- tenesmus
- haematochezia
- ^ defaeatory frequency
- Ribbon-like feaces
- Rectal prolapse
- weight loss
Where are 60-80% colorectal adenocarcinomas? What would be felt on rectal exam?
- Mid-caudal rectum, palpable on rectal exam
- Polypoid mass, irregular mucosal surface, annular stricture
What diagnostics may be used to diagnose colorectal neoplasia?
Radiography (abdo and thorax)
Ultrasound guiding FNA
Colonoscopy and grab biopsy
What are the 2 types of surgical treatments of colorectal neoplasia? Are these curative?
- Submucosal resection
- Wide surgical excision [3cm] with intestinal resection and anastomosis
> treatment but not cure
How can relaxation of the anus for transanal surgery be acheived?
Epidural
When is rectal pull-through for surgery advocated?
Lesion in caudal 1/3 to 1/2 of rectum
