Surgery of the large intestine, rectum, and anus Flashcards
(49 cards)
1
Q
What is a cecal inversion? What are the typical signs?
A
- Cecal inversion = cecal intussusception
- Signs
- Diarrhea
- Hematochezia
- Weight loss
- Tenesmus
2
Q
What is the treatment for cecal inversion?
A
- Manual reduction
- Colotomy if necessary
- Typhylectomy
3
Q
How do you perform a typhylectomy?
A
- Ligate arterial supply
- Dissect ileocolic fold
- Milk out contents
- Transect and suture
4
Q
How is blood supply and healing of the large intestine different from the small intestine?
A
- Higher bacteria count
- Increased collaginase 1-3 days after sx
- Segmental blood supply
- Ileocolic, cranial mesenteric, caudal mesenteric
- Major: ileocolic, cranial mesenteric
- If you ligate the segmental blood supply you must remove that section–will get necrosis
- Ileocolic, cranial mesenteric, caudal mesenteric
5
Q
What are the most common cecal tumors?
A
Leiomyoma and leiomyosarcoma
6
Q
What are the causes of megacolon?
A
- Usually idiopathic (62%)
- Pelvic obstruction (23%)
- Neurologic (6%)
- Endocrine
7
Q
What are the treatment options for megacolon? What are the specifics for medical management?
A
- Medical management
- Correct dehydration
- Deopstipate
- Inc. fiber diet
- Stool softeners
- Osmotic laxatives (lactulose)
- Prokinetic agents (cisapride)
- Subtotal colectomy
8
Q
What are the goals of subtotal colectomy in the treatment of megacolon?
A
Goal is to remove as much colon as possible
9
Q
What are the advantages/disadvantages of ileocolostomy and colocolostomy when performing a subtotal colectomy?
A
- Colocolostomy
- Remove entire colon and reattach it, leaving ileocolic valve intact
- Preferable
- Tension free apposition more difficult (impossible in some patients)
- Remove entire colon and reattach it, leaving ileocolic valve intact
- Ileocolostomy
- Tension-free closure
- Exposes patient to bacteria
- Increased incidence of severe diarrhea
- Tend to do worse than colocolostomy patients
10
Q
What is the typical post-operative course after subtotal colectomy? Prognosis?
A
- Fluids 1-3days
- Analgesics
- Continue antibiotics if gross contamination
- Feed w/in 24hrs
- Diarrhea should improve in 2-8wks
- Good prognosis
- Dogs–fair to guarded
11
Q
What is the incidence of dehiscence after intestinal surgery? What is the prognosis?
A
Occurs at about the same rate as with the SI, but can be much worse due to high amounts of bacteria
12
Q
What is atresia ani (tell me all the things)?
A
- Stenosis or persistent membrane of the anus or rectum
- Most commonly reported anomaly
- Increased incidence in toy poodles and Boston terriers
- Signs occur at a few wks of age
- Clinical signs
- Straining
- Anal dimple
- Perineal swelling
13
Q
Tell me everything about rectovaginal fistulas
A
- Often associted w/ atresia ani
- Vulvar irritation, cystitis
- Passage of urine through rectum or feces through vula
- Diagnose with positive contrast
- Treat by transecting and closing defect
- Treat underlying UTI
14
Q
3 facts of anogenital clefts?
A
- Common opening for anus and genital tract-cloaca
- Leads to ascending UTI
- Treat with plasty procedure
15
Q
Differentiate between anal and rectal prolapse
A
- Anal prolapse
- Incomplete prolapse
- Anal mucosa protrudes from orifice
- Determine underlying cause and treat
- Manually reduce and place purse string
- Rectal prolapse
- Complete–all layers of rectum protrude through anal orifice
16
Q
What are the predisposing factors for rectal prolapse?
A
- Parasites
- Colitis
- Urogenital disease
- Younger patients
- Tumors
17
Q
How do you differentiate between rectal prolapse and prolapsed intussusception?
A
If actual prolapse, blunt probe/finger cannot be inserted
18
Q
How do you treat a rectal prolapse if the tissue is still viable?
A
- Manually reduce
- Facilitate reduction with saline, lubricants, or mannitol
- Place purse string to keep reduced but allow soft feces
- Leave for several days
19
Q
How do you treat a rectal prolapse with non-viable tissue?
A
- Surgically prep area
- Place 4 full-thickness stay sutures
- Use test tube to minimize contamination
- Resect 1-2cm from anus
- Simple interrupted
- Reduce prolapse
20
Q
What are the treatment options for a recurrent rectal prolapse?
A
Incisional colopexy
Non-incisional colopexy
21
Q
Describe the procedure of a non-incisional colopexy for treatment of recurrent rectal prolapse
A
- Ventral celiotomy
- Cranial traction on colon
- Reduce prolapse
- Engage submucosa
- Antimesenteric border
- Left abdominal wall
- 2 rows of 5-6 non-absorbable sutures
22
Q
Describe the procedure for an incisional colopexy
A
- Similar to gastropexy
- > 3cm incision through serosa and muscular layers
- Incision through transverse abdominus muscle
- Can perform in more than one area
23
Q
What is the most common malignant rectal tumor in dogs? What is the signalment?
A
- Most common: adenocarcinoma
- German shepherds and poodles predisposed
- Older dogs
- Increased incidence in males
- Not quite as aggressive as SI
24
Q
What is the most common tumor in the rectum? What is the signalment?
A
Adenomatous polyp
- Most commonly found in distal rectum
- Collies predisposed
- Can undergo malignant transformation
- Single or multiple lesions (higher incidence of transformation in multiple lesions)
25
What are the clinical signs of rectal tumors?
* Tenesmus
* Dyschezia
* Painful defecation
* Rectal prolapse
* Protrusion of polyp
26
How do you diagnose rectal tumors?
* Direct observation
* Digital rectal palpation
* Colonoscopy/proctoscopy
* May help determine extent
* Biopsy
* Helps determine type, stage, and sx indication
* **Always** submit excised mass
* Thoracic and abdominal rads
27
What is the pre-operative treatment for rectal tumors?
* Withhold food 24-48hrs prior
* Consider multiple warm water enemas up to 12hrs prior
* If given w/in 12hrs of sx, fluid can be retained --\> can lead to more difficult sx or contamination
* Enemas contraindicated with obstructive lesions
* Consider prophylactic antibiotics
* Aerobic and anaerobic activity
28
What are the indications for the trans-anal approach when removing rectal tumors?
* Excision of small, non-invasive pedunculated polyps
* Lesions in the caudal 4-6cm of rectum
29
What are the indications/procedure for using the dorsal approach when removing rectal tumors?
* Used for tumors in the mid-rectum
* Place purse string
* Make inverted U incision between tail and anus and tubur ischium laterally
* Transect rectococcygeus muscles
* Bluntly dissect between levator ani and external anal sphincter muscles
* Place stay sutures proximally and distally
30
What is the modified rectal pull through approach for removing rectal tumors used for? Describe the procedure
* Used for approach to the mid/caudal rectum
* Evert rectal wall through the anus
* Place multiple stay sutures
* Make incision proximal to anocutaneous junction leaving a 1.5cm cuff of rectum
* Bluntly dissect rectum from external anal sphincter
* Mobilize rectum caudally and resect
31
What is the Swanson's rectal pull through approach for rectal tumor removal? When is it used?
* Combines trans and anal abdominal approach
* Used for more extensive lesions of the rectum
32
Describe the lateral approach to rectal tumor removal
* Limits approach to one side of rectum
* Used for rectal diverticulum or laceration
* Approach from base of tail to ischium 1-3cm lateral to anus
* Separate tissue between levator ani and ext anal sphincter to expose lateral rectum
* Preserve caudal rectal nerve
* Procedure **rarely** used
33
Describe the ventral approach for rectal tumor removal
* Lesions at colorectal junction
* Pubic osteotomy 1, 2
* Pubic symphysiotomy 1, 3
34
What is the medical management of anal saculitis?
* Express gland
* Cannulate and irrigate
* Infuse abx/steroids
* +/- systemic abx
* Drain/flush abscess
* Treat underlying problem
* Diarrhea
* Allergies
35
What is the surgical management for anal saculitis?
When is it indicated?
* Anal sacculectomy
* Indicated when medical management fails or neoplasia is suspected
36
Surgical management for anal saculitis should be performed after \_\_\_\_\_\_\_.
inflammation is controlled
37
Describe a closed anal sacculectomy
* Often performed in ferrets and for neoplasia
* Blunt probe/instrument
* Paraffin injection
* Catheter
38
Describe the technique for an open anal sacculectomy
* Exposes secretory lining
* Insert 1 blade of scissors into sac
* Apply upward pressure to tips to minimize tissue cut or insert groove director or probe through duct into anal sac
* Incise over instrument with caudal tension on instrument to minimize damage to sphincter
* Dissect anal sac from anal sphincter
39
What are the potential complications of anal sac surgery?
* Infection
* Draining tracts
* Incomplete removal of anal sac
* Must excise to resolve
* Fecal incontinence
* Trauma to caudal rectal nerve or external anal sphincter
* Give 3-4mo for reinnervation
40
What is the most common malignant tumor of the anal sac?
Apocrine gland adenocarcinoma
41
What are the characteristics/signalment of apocrine gland adenocarcinomas?
* Highly malignant
* Regional LN metastasis
* Older spayed female dogs???
* Perianal swelling or incidental finding
* 25-90% have paraneoplastic syndrome
42
What is paraneoplastic syndrome?
* Hypercalcemia and hypophosphatemia
* PU/PD
* Muscle weakness
* Vomiting
43
What is the prognosis of apocrine gland adenocarcinoma?
* Poor
* 50% have mets on presentation
* MST \< 1yr with metastasis
* MST 16-18mo with no mets
* Monitor Ca levels pre- and post-op
44
What is the management of perianal adenomas?
* Regress with castration
* Castration/surgical excision
45
What are perianal fistulas?
Chronic suppurative ulcerative tracts
46
What are the potential etiologies of perianal fistulas?
* Broad base low carried tail
* Abscessed anal glands
* Hair follicle infection
* **Immune-mediated**
47
What is the signalment of perianal fistulas? Signs/diagnosis?
* Middle-aged German shepherds
* Diagnosis/signs
* Presence of fistulous tract
* Tenesmus
* Dischezia
* Licking
* Malodorous perianal discharge
* Pain
48
What is the medical management for perianal fistulas?
* Perianal cleansing
* Antibiotics
* Immunosuppressive therapy
* Prednisolone
* Cyclosporine
* Azathioprine
49
What are the surgical managements available for perianal fistulas?
* Surgical excision
* Concurrent anal sacculectomy
* Cryosurgery
* Fulguration
* Tail amputation
* Laser excision
* Anoplasty
