Surgical approach to the LI in small animals Flashcards

1
Q

2 surgical approaches for colorectal surgery

A
  • ventral midline laparotomy
  • pelvic split
  • transanal
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2
Q

Which nerves pass through obturator foramen?

A

sciatic and obturator nn

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3
Q

Define colotomy

A

Full thickness biopsy of the colon (same basic principles as enterotomy)

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4
Q

How is LI resection and anastomosis different to that in the SI?

A

Same basic principles but biggest difference is the delayed healing time of the LI

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5
Q

Risk if you remove too much colon = ?

A

Faecal incontinence (loss of reservoir and absorptive capacities)

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6
Q

What happens if you disrupt ileocaecocolic junction?

A

Disruption of ileal function - normally this prevents retrograde flow of colonic backeria into SI to decrease risk of SIBO

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7
Q

How much of a rectal resection causes faecal incontinence?

A

6cm or more

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8
Q

How to anastomose LI ?

A

sutures or staples

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9
Q

Describe the suture you’d use for LI anastomosis. Why? 4

A

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.

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10
Q

How is a stapler used?

A

Inserted via an incision in th ecaecum or via the anus.

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11
Q

How does an end-to-end anastomosis stapler work?

A

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.

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12
Q

Complications of colorectal surgery 7

A
  • dehiscence –> septic peritonitis
  • wound infection
  • abscess
  • faecal incontinence
  • stricture and tenesmus
  • rectal prolapse
  • haematoxhezia
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13
Q

Name 3 surgical diseases of colon and rectum

A

Megacolon, neoplasia, rectal prolapse

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14
Q

Causes of megacolon - 2 (examples)

A
  • PRIMARY/IDIOPATHIC - cats
  • SECONDARY - pelvic fractures, intrapelvic SOL (neoplasia, lymphadenopahty, abscess), colorectal neoplasia, colorectal abscess, perineal hernia, inappropriate diet
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15
Q

Diagnosis - megacolon

A
  • Signs (chronic constipation, tenesmus, vomiting, anorexia, weight loss)
  • Large colon containing faecal material, dehydration, poor BCS
  • rule out underlying cause for constipation
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16
Q

Megacolon -treatment

A

MEDICAL OR SURGICAL:
MEDICAL (manual evacuation of the colon, laxatives, prokinetics, frequent walks, high fibre/low residue diet)
SURGERY (subtotal colectomy)

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17
Q

Prognosis - megacolon

A

Good

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18
Q

Post-op complications of megacolon- 5

A
  • Recurrent constipation
  • Increased defaecatory frequency
  • soft to watery faeces
  • tenesmus
  • rectal prolapse
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19
Q

Describe possible colorectal neoplasias and their frequency

A

BENIGN (50%) - adenomatous polyps (up to 50% show malignant transformation), leiomyomas
MALIGNANT (50%) - adenocarcinoma (commonest), leiomyosarcoma, lymphoma, haemangiosarcoma, plasmacytoma

20
Q

Which dog breeds are predisposed to adenocarcinomas? 4

A

GSD, Great Dane, Doberman, Boxer

21
Q

Clinical signs - colorectal neoplasia - 6

A
tenesmus
haematochezia
increased defaecatory frequency
ribbon-like faeces (from being pushed past growth)
rectal prolapse 
weight loss
22
Q

Diagnosis - colorectal neoplasia

A

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

23
Q

What catheter would you use to prevent a barium contrast coming back out of the anus?

A

Foley catheter (like a human urinary catheter)

24
Q

Treatment - colorectal neoplasia - 2

A
  • Submucosal resection

- Wide surgical excision with intestinal resection and anastomosis

25
Q

What causes anal relaxation that assists with submucosal resection?

A

An epidural (in addition to the GA)

26
Q

Do you suture/staple when performing colorectal resection and anastomosis b/w pelvic bones

A

Stitches easier (space-wise) in this region

27
Q

What do you do if you need to do a full thickness biopsy from the last part of the rectum?

A

Cut the rectum at the level of the anocutaneous junction and then pull rectum out

28
Q

Prognosis - adenomatous polyps

A

Surgical resection –> can result in a cure. 17% recurr at 9-12mo, 25% malignant transformation at 9-17mo, median survival >2years (v good)

29
Q

Prognosis - adenocarcinomas

A

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

30
Q

Prognosis if you use conservative management with faecal softeners

A

Median survival time 15 months

31
Q

Prognosis - submucosal resection alone

A

A more benign surgery (complications resolve in 1 week), long term follow up - mean disease free interval = 37 months

32
Q

3 causes of rectal prolapse

A

GIT parasites, rectal neoplasia, perineal hernia

33
Q

Treatment - rectal prolapse - 4

A

Anthelmintics, faecal softeners, low residue diet, sedatives

34
Q

Structure - anal sacs

A

Skin invaginations at 4 and 8 o’clock position within rectum

35
Q

Clinical signs - anal sac impaction/inflammation/infection

A

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.

36
Q

Treatment - anal sac impaction

A

Manual expression

37
Q

Treatment - anal sacculitis/abscess

A

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)

38
Q

Indication for anal sacculectomy types (2)

A

Repeat problems with anal glands. Can be an open or closed type.

39
Q

Complication risk - anal sacculectomy

A

UNCOMMON

  • faecal incontinence
  • persistent infection with draining tracts
40
Q

DDx for anal sac apocrine gland adenocarcinoma - 2

A
  • PERIANAL ADENOMA
  • PERIANAL ADENOCARCINOMA
  • PARANEOPLASTIC SYNDROME (–> hypercalcaemia -> PU/PD)
41
Q

Diagnosis and tumour staging - anal sac apocrine gland adenocarcinoma - 4

A
  • PE (esp. sublumbar LNs)
  • Haematology, biochemistry, urinalaysis
  • Fine needle aspirate (usually sufficient for Dx)/incisional biopsy
  • radiography/ultrasound (thorax/abdomen)
42
Q

Treatment - anal sac apocrine gland adenocarcinoma - 3

A

Combination (because hard to get a good margin around tumour) - surgery, radiation therapy, chemotherapy

43
Q

Prognosis - anal sac apocrine gland adenocarcinoma

A

treatment with surgery - 548 d

all 3 - 956 days

44
Q

How may anal furunculosis present?

A

May be just bleeding (GSDs prone especially)

45
Q

Treatment - anal furunculosis

A
  1. ) AB
  2. ) immuno-modulatory therapy (cyclosporine = number 1 choice but very expensive) Alternative = ketoconazole (lowers dose of cyclosporine needed but has side effects so avoid)
46
Q

Diagnosis - anal furunculosis

A
  • Anaesthetise
  • Check anal sacs are intact (if not -remove)
  • Biopsy (–>culture, histopathology and determine if there is a significant bacterial component)
47
Q

What is tacrolimus? Use?

A

Another immuno-modulatory drug that can be used for anal furunculosis but it is a cream therefore can’t be used as a first line treatment but can keep lesions at bay long-term