GI surgery large intestine Flashcards
recto-colonic surgery - dehiscence and strength of tissue considerations
- In humans large intestinal anastomoses dehisce at higher rate then small intestinal
- Colonic wound strength returns more slowly than SI (30% of normal at 48 hrs, 75% of normal at 4 months)
- Colonic wound healing is compromised by poorer blood supply in the mid-rectum (preserve cranial rectal artery)
- Large anaerobic load present
- Tension: reduces blood supply, oxygen tension
ileoceco-colic junction resection leads to what?
Leads to loss of antegrade and retrograde reflux regulation
-antegrade effects: diarrhea, nutrient malabsorption, dehydration
-retrograde effects: small intestinal bacterial overgrowth
ileum resection leads to…
-bile acid reabsorption and cobalamin absorption impaired
ICJ RESECTION principles
- where to dissect? considerations?
- Similar principles to large intestinal resection
- Dissect close to margin of the bowel to preserve as much collateral circulation as possible
- Sometimes metastatic lymph nodes incorporated into resection
- Luminal disparity usually has to be managed as colon larger than ileum/jejunum
- Preserve as much ileum as possible without compromising neoplastic margins
INDICATIONS FOR COLO-RECTAL RESECTION
- Feline megacolon
- Colorectal neoplasia
- Colonic foreign bodies > Can usually be milked out of the rectum
- No need for full-thickness colonic biopsy – don’t do it!!
FELINE MEGACOLON
- causes?
- Mostly idiopathic, also pelvic stenosis or neurologic disease
- Caused by disturbance in the activation of smooth muscle myofilaments
feline megacolon clinical signs
C/S: fecal tenesmus, pain defecating, vomiting, anorexia, dehydration
feline megacolon Dx
C/S and radiographs showing dramatic colonic distension with fecal impaction
FELINE MEGACOLON - MANAGEMENT
- Medical management: Stool softeners and enemas, IV fluids, Cisapride
> Rarely successful for long-term management - Surgical management: Subtotal colectomy
SUBTOTAL COLECTOMY
- do we preserve ICJ? what if we remove it? what if we leave it?
- Can be performed with or without preservation of the ileocecocolic jct
- If IC jct removed can predispose to small intestinal bacterial overgrowth (SIBO)
- Cats with IC jct resection may have softer stools post-op
- Only resect IC jct if excessive tension on closure
- If leave, even modest amount of colon can get recurrence
ANAL SACCULECTOMY -INDICATIONS
- Neoplastic
> Apocrine gland anal sac adenocarcinoma (AGASACA) - Non-neoplastic
> Sacculitis
Apocrine gland anal sac adenocarcinoma (AGASACA)- signalment? how usually found? how often metastatic?
- Median age 10 - 11 yrs old
- Commonly incidental finding at rectal exam or visible mass present
- Evidence of metastatic disease in 36-39% of dogs
> Ileo-lumbar LNs, spleen, liver, thoracic LNs, lungs
> Rare in cats
Apocrine gland anal sac adenocarcinoma (AGASACA)- how do get diagnosis? common related issue?
- FNA of mass is usually diagnostic
- Paraneoplastic hypercalcemia is common
Apocrine gland anal sac adenocarcinoma (AGASACA)- prognosis?
- Surgery alone 12-18 months BUT a variety of factors
- Size of tumor
- Metastatic LNs?
- Presence of hypercalcemia
- Chemotherapy may help in metastatic scenario
ANAL SACCULECTOMY -AGASACA
- possible complications
- Infection / rectal perforation
- Fecal incontinence
- Local recurrence
ANAL SACCULECTOMY -AGASACA
0 how to perform
Closed technique only for AGASACA
* Lumen of anal sac not entered
* Incision over anal sac
* Dissect from surrounding tissue
* Duct ligated, transected
SPLENECTOMY -HILAR LIGATION
- what is it? when to use? timing?
- Individual ligation of hilar vessels
- Diffuse disease
- Small masses
- Increased sx time
SPLENECTOMY
-RAPID / 4-CLAMP TECHNIQUE
- pros and cons
- Advantages
> Rapid, less dissection of hilar vessels required - Disadvantages
> Need to ID vascular structures
SPLENECTOMY -POSTOPERATIVE CARE
Continuous monitoring required!
* Analgesia (opioid +/- NSAID)
* ECG
* PCV/TS
* +/- Blood transfusion
* IV fluids
spleniic neoplasias that are common
Benign and Malignant
* Hemangiosarcoma
* Lymphoma, hemangioma,
* Non-traumatic hemoab
are benign or malignantsplenic masses usually larger?
- Higher weight in benign masses
- Higher Mass:Spleen ratio
hemoperitoneum is strongly associated with what splenic disease?
- 76% malignant neoplasia
- of these, almost all hemangiosarcoma
> metastasis often
HSA Px
4-6 months w chemo
4-6 weeks without
incidentally found splenic mass - what is it, probably? reccomendation?
Recent study —> 70% (74/105) dogs had benign disease
* Recommend splenectomy; confirm dx with histopathology
* If HSA, still may have an improved prognosis compared to if hemoabdomen ensues
