Flashcards in Surgical approach to the LI in small animals Deck (47):
2 surgical approaches for colorectal surgery
-ventral midline laparotomy
Which nerves pass through obturator foramen?
sciatic and obturator nn
Full thickness biopsy of the colon (same basic principles as enterotomy)
How is LI resection and anastomosis different to that in the SI?
Same basic principles but biggest difference is the delayed healing time of the LI
Risk if you remove too much colon = ?
Faecal incontinence (loss of reservoir and absorptive capacities)
What happens if you disrupt ileocaecocolic junction?
Disruption of ileal function - normally this prevents retrograde flow of colonic backeria into SI to decrease risk of SIBO
How much of a rectal resection causes faecal incontinence?
6cm or more
How to anastomose LI ?
sutures or staples
Describe the suture you'd use for LI anastomosis. Why? 4
Single laye rof simple interrupted appositional using a monofilament, PDS2 (loses 26% strength in 14 days). WHY? optimises wound healing, faster gain in tensile strength, minimise decrease in lumen diameter, decreased incidence of complications.
How is a stapler used?
Inserted via an incision in th ecaecum or via the anus.
How does an end-to-end anastomosis stapler work?
causes an inverted anastomosis (i.e. there is some inversion of wound (makes the risk of stricture slightly higher). Causes a little post-op bleeding from rectum.
Complications of colorectal surgery 7
-dehiscence --> septic peritonitis
-stricture and tenesmus
Name 3 surgical diseases of colon and rectum
Megacolon, neoplasia, rectal prolapse
Causes of megacolon - 2 (examples)
-PRIMARY/IDIOPATHIC - cats
-SECONDARY - pelvic fractures, intrapelvic SOL (neoplasia, lymphadenopahty, abscess), colorectal neoplasia, colorectal abscess, perineal hernia, inappropriate diet
Diagnosis - megacolon
-Signs (chronic constipation, tenesmus, vomiting, anorexia, weight loss)
-Large colon containing faecal material, dehydration, poor BCS
-rule out underlying cause for constipation
MEDICAL OR SURGICAL:
MEDICAL (manual evacuation of the colon, laxatives, prokinetics, frequent walks, high fibre/low residue diet)
SURGERY (subtotal colectomy)
Prognosis - megacolon
Post-op complications of megacolon- 5
-Increased defaecatory frequency
-soft to watery faeces
Describe possible colorectal neoplasias and their frequency
BENIGN (50%) - adenomatous polyps (up to 50% show malignant transformation), leiomyomas
MALIGNANT (50%) - adenocarcinoma (commonest), leiomyosarcoma, lymphoma, haemangiosarcoma, plasmacytoma
Which dog breeds are predisposed to adenocarcinomas? 4
GSD, Great Dane, Doberman, Boxer
Clinical signs - colorectal neoplasia - 6
increased defaecatory frequency
ribbon-like faeces (from being pushed past growth)
Diagnosis - colorectal neoplasia
RECTAL EXAM: 60-80% are in mid-caudal rectum. Check also for polypoid mass, irregular mucosal surface, annular stricture
RADIOGRAPHY - abdomen and thorax
ULTRASOUND - fine needle aspirate
COLONOSCOPY - grab biopsy
What catheter would you use to prevent a barium contrast coming back out of the anus?
Foley catheter (like a human urinary catheter)
Treatment - colorectal neoplasia - 2
-Wide surgical excision with intestinal resection and anastomosis
What causes anal relaxation that assists with submucosal resection?
An epidural (in addition to the GA)
Do you suture/staple when performing colorectal resection and anastomosis b/w pelvic bones
Stitches easier (space-wise) in this region
What do you do if you need to do a full thickness biopsy from the last part of the rectum?
Cut the rectum at the level of the anocutaneous junction and then pull rectum out
Prognosis - adenomatous polyps
Surgical resection --> can result in a cure. 17% recurr at 9-12mo, 25% malignant transformation at 9-17mo, median survival >2years (v good)
Prognosis - adenocarcinomas
Cure is possible with complete surgical excision due to low rate of distant metastases but complete excision often difficult due to tumour location. Medial survival 22 months
Prognosis if you use conservative management with faecal softeners
Median survival time 15 months
Prognosis - submucosal resection alone
A more benign surgery (complications resolve in 1 week), long term follow up - mean disease free interval = 37 months
3 causes of rectal prolapse
GIT parasites, rectal neoplasia, perineal hernia
Treatment - rectal prolapse - 4
Anthelmintics, faecal softeners, low residue diet, sedatives
Structure - anal sacs
Skin invaginations at 4 and 8 o'clock position within rectum
Clinical signs - anal sac impaction/inflammation/infection
HISTORY - perineal irritation (scooting, licking, biting, discomfort on defaecation)
PE - enlarged non-painful/painful anal sac, secretions (normal - liquid brown, abnormal - thick white/yellow/green). Reddened inflamed skin or draining tract overlying region of anal sac suggestive of infection or ruptured abscess.
Treatment - anal sac impaction
Treatment - anal sacculitis/abscess
Sedation/anaestheisa, catheterise duct opening - lacrimal cannulae, collect sample (culute and cytology), lavage anal sac (0.9% saline), instill dexamethasone and ABs, systemic AB (if evidence of abscess or systemic disease), topical treatment (if yeast overgrowth is indicated on cytology)
Indication for anal sacculectomy types (2)
Repeat problems with anal glands. Can be an open or closed type.
Complication risk - anal sacculectomy
-persistent infection with draining tracts
DDx for anal sac apocrine gland adenocarcinoma - 2
-PARANEOPLASTIC SYNDROME (--> hypercalcaemia -> PU/PD)
Diagnosis and tumour staging - anal sac apocrine gland adenocarcinoma - 4
-PE (esp. sublumbar LNs)
-Haematology, biochemistry, urinalaysis
-Fine needle aspirate (usually sufficient for Dx)/incisional biopsy
Treatment - anal sac apocrine gland adenocarcinoma - 3
Combination (because hard to get a good margin around tumour) - surgery, radiation therapy, chemotherapy
Prognosis - anal sac apocrine gland adenocarcinoma
treatment with surgery - 548 d
all 3 - 956 days
How may anal furunculosis present?
May be just bleeding (GSDs prone especially)
Treatment - anal furunculosis
2.) immuno-modulatory therapy (cyclosporine = number 1 choice but very expensive) Alternative = ketoconazole (lowers dose of cyclosporine needed but has side effects so avoid)
Diagnosis - anal furunculosis
-Check anal sacs are intact (if not -remove)
-Biopsy (-->culture, histopathology and determine if there is a significant bacterial component)