Surgical approach to the colon, rectum and anus in small animals Flashcards Preview

Alimentary > Surgical approach to the colon, rectum and anus in small animals > Flashcards

Flashcards in Surgical approach to the colon, rectum and anus in small animals Deck (32):
1

colorectal surgery - surgical approaches

Ventral Midline Laparotomy
Dorsal Perineal Approach
pelvic split
transanal

2

colotomy

Full thickness biopsy of the colon
Same basic principles as enterotomy
risk of infection + wound breakdown

3

Large intestinal resection & anastomosis

Same basic principles as for small intestine, but must
respect delayed healing of large intestine

4

How much colon can you remove?

Removal of majority of colon - Loss of reservoir & absorptive capacities, ↑fecal frequency, watery faeces
Preservation of ileocaecolic junction - preserves ileal function, Prevents retrograde flow of colonic bacteria into SI -↓risk of bacterial overgrowth

5

how much rectum can be removed

Rectal resections of 6cm or more are consistently
associated with faecal incontinence

6

Large intestinal anastomosis - sutures - aims

Optimise wound healing
Faster gain in tensile strength
Minimise decrease in lumen diameter
Decreased incidence of complications

7

Large intestinal anastomosis - staples

Rapid and reliable
Inserted via an incision in the caecum or via the anus
inverted anastomosis
Post-op bleeding
Higher anastomotic bursting pressures on day 7 compared to sutured anastomoses

8

complications of colorectal

Dehiscence & septic peritonitis
Wound infection
Abscess
Faecal incontinence
Stricture & tenesmus
Rectal prolapse
haematochezia

9

megacolon - define

Flaccid enlargement of the colon, distension of the colon
with feces and loss of function of the colonic muscle

10

when would you find Primary/idiopathic megacolon

in cats

11

secondary megacolon - causes

pelvic fractures
intrapelvic space-occupying lesions
Colorectal neoplasia
Colorectal abscess
Perineal hernia
Inappropriate diet

12

megacolon - clinical signs

Chronic constipation, tenesmus, vomiting, anorexia, weight loss
Large colon containing fecal material, dehydration, poor body condition
Rule out underlying cause for constipation

13

megacolon - treatment

Treat underlying disease
Medical - Manual evacuation of colon, Laxatives, Prokinetics, Frequent walks, High fibre, low residue diet
Surgery - subtotal colectomy
Post-op complications - Recurrent constipation, Increased defaecatory frequency, Soft to watery faeces, Tenesmus, Rectal prolapse
Prognosis - Good

14

colorectal neoplasia

50/50 benign vs malignant
benign - Adenomatous polyps, leiomyomas - can transform to be malignant
malignant - Adenocarcinoma, leiomyosarcoma, lymphoma,
haemangiosarcoma, plasmacytoma

15

Colorectal neoplasia - signalment

Older dogs: 6-9 yrs
Adenocarcinomas

16

Colorectal neoplasia - history

Tenesmus
Haematochezia
Increased defecatory frequency
Ribbon-like faeces
Rectal prolapse
Weight loss

17

Colorectal neoplasia: diagnosis

Rectal exam - polypoid mass, irregular mucosal surface, annular stricture
Radiography: abdomen & thorax
Ultrasound, fine needle aspirates
Colonoscopy, grab biopsy

18

Colorectal neoplasia: treatment

Submucosal resection
Wide surgical excision with intestinal resection &
anastomosis

19

colorectal neoplasia - prognosis

Adenomatous polyps - Surgical resection can result in a cure, 17% dogs: recurrence at 9-12 months, 25% dogs: malignant transformation at 9-17 months, Median survival > 2 years
Adenocarcinomas - Cure is possible with complete surgical excision due to low
rate of distant metastasis, but complete excision o
ften difficult due to tumour location, Median survival: 22 months
Conservative management with fecal softeners - Mean survival time: 15 months

20

Rectal prolapse - causes

Gastrointestinal parasites
Rectal neoplasia
Perineal hernias

21

Rectal prolapse - treatment

Anthelmintics
Faecal softeners
Low residue diet
Sedatives

22

Anal sac impaction, inflammation & infection

History - Perineal irritation: scooting, licking or biting,
discomfort on defecation
Physical Exam - Enlarged non-painful/painful anal sac
Abnormal 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

23

Anal sac impaction, inflammation & infection - treatment - medical

Impaction - Manual expression
Anal sacculitis/abscess - Sedation or anaesthesia, Catheterise duct opening: lacrimal cannulae, sample for culture and cytology, Lavage anal sac with 0.9% saline, dexamethasone and antibiotics
Systemic antibiotics, if evidence of abscess or systemic disease
Topical treatment of yeast overgrowth if indicated on cytology

24

Anal sac impaction, inflammation & infection - treatment - surgical

anal sacculectomy

25

anal sacculectomy - Complications

uncommon
Fecal incontinence if dissection was traumatic or aggressive - usually temporary unless both caudal rectal nerves were cut
Persistent infection with draining tracts - fail to remove all anal sac tissue

26

Anal sac apocrine gland adenocarcinoma

Highly malignant: 50% metastases at diagnosis

27

Anal sac apocrine gland adenocarcinoma - Perianal adenoma

benign, Common, Intact male, spayed females, Castration plus surgery

28

Anal sac apocrine gland adenocarcinoma - Perianal adenocarcionma

Malignant, Rare, Treat as anal sac adenocarcinoma

29

Anal sac apocrine gland adenocarcinoma - Paraneoplastic syndrome

Hypercalcaemia
polyuria and polydipsia

30

Anal sac apocrine gland adenocarcinoma - diagnosis

Physical exam
Haematology, biochemistry, urinalysis
Fine needle aspirate/ incisional biopsy
Radiography /ultrasound of thorax and abdomen

31

Anal sac apocrine gland adenocarcinoma - treatment

Surgery
Radiation therapy
Chemotherapy - mitoxantrone

32

Anal sac apocrine gland adenocarcinoma - prognosis

Treatment incl. Surgery – 548 days
All 3 of the above – 956 days