---start---
dr brockman
11.3.98

sx conditions of pancreas and spleen 
(liver and biliary will be tomorrow)

there isn't that much pancreatic 
surgery done, overall. there are some things to know about the pancreas, 
though. you already heard about physiology...let's review anatomy - there 
are two limbs - the duodenal and gastric or left limb. the gastric limb 
is in dorsal omental attachment to greater curvature of the stomach. to 
see it you have to surgically reflect the omentum cranially or make a 
window in ventral sheet of omentum. so remember, gastric limb isn't 
immediately visible. the duodenal limb most of you saw during your spay 
surgery. it's readily visible when you exteriorize the duodenum as you do 
to search for the right ovarian pedicle. the pancreatic ductal system is 
very variable.  typically in dogs there are two main ducts from the 
pancreas, one joining the major duodenal papilla with the common bile 
duct - here is a big difference from cats - most cats only have one 
pancreatic duct. that compromises your ability to do proximal duodenal 
resection/distal gastrectomy in cats. the Bilroth 2, for example, would 
be a problem in cats with only one pancreatic duct because you lose the 
major duodenal papilla and do a cholecystojejunostomy. 

there are wide 
anastomoses b/w the pancreatic ducts in dogs so anastomosing one is no 
big deal if the other is patent.

blood supply to pancreas is from the 
celiac artery and cranial mesenteric artery. there is a large caudal 
pancreaticoduodenal artery from the cranial mesenteric, and also the 
cranial pancreaticoduodenal from the celiac a. mostly we find the 
duodenal limb of pancreas close to duodenum cranially and see pancreas 
wandering into mesoduodenum caudally. the hard part is trying to separate 
pancreas away from duodenum while preserving duodenal blood supply, 
because they share a common vessel. 

the ductal system - there is a 
highly variable system. most dogs about 48% have a large duct entering 
the accessory duodenal papilla - so getting rid of the duct at the major 
duodenal papilla is not big deal. but about 22% of dogs have a small duct 
from the caudal pancreas going to major papilla and then larger one. some 
dogs have two equal sized ducts. less frequently, dogs only have one real 
duct, or have more than 2 ducts. generally, the major duct is at the 
minor duodenal papilla so in dogs, you can generally get rid of major 
duodenal papilla as long as you divert bile flow with one of the other 
procedures we talked about.

indications for surgery of pancreas: few, 
far between

-chronic pancreatitis esp fibrosing type can be an 
indication for surgery, but not really pancreatic surgery. this causes 
sometimes duodenal obstruction and more commonly simply causes biliary 
obstruction. so surgical tx for chronic fibrosing pancreatitis involves 
biliary diversion, cholecystoduodenostomy or -jejunostomy. 

-acute 
pancreatitis as discussed by Dr W 95-99% of the time is a 
contraindication for surgery, b/c risk of exacerbation of pancreatitis is 
extreme, and potential gains are unclear in most cases. we do, however, 
sometimes get invited by medicine department to do surgery on these cases 
because either they are failing traditional medical management, or on u/s 
they have found a specific site within the pancreas that is making either 
a sterile abscess, or what they call in pancreatic parlance a phlegmon, a 
cystic inflammatory structure. if this is isolated to one pancreatic 
limb, it may help to resect the area. but truly, indications for surgery 
are unclear in small animals. 

case: 10 yr old mini schnau with 
Cushing's and APN documented by u/s and serology, etc. this dog was 
treated medically x 1 week. serial u/s found mostly a duodenal limb 
involvement and it was getting walled off into a phlegmon type structure. 
at surgery, they found the distal part of the duodenal limb of pancreas 
to be very discolored, blackened, necrotic - with an abscessed area and 
autolyzed or saponified fat around it. truly disgusting, really. so since 
there was normal looking pancreas at the gastric limb area, it seemed it 
would help to remove the yucky part. they did that, and placed a 
jejunostomy tube for postop feeding, to reduce stimulation of pancreatic 
secretions. as Dr Holt probably already explained or will explain, when 
you have an inflammatory process like this in the abdomen, the most 
helpful thing you can do is provide permanent or semipermanent drainage. 
in people, pancreas is retroperitoneal but in animals, it is peritoneal. 
so you need a drainage technique. penrose drains may do it, but the 
majority of times we treat such global peritonitis, we leave the 
peritoneal cavity loosely open, so that inflammatory exudate can drain 
out through the gaping peritoneal closure. you do have to use sterile 
supportive dressings over these big wounds, and do daily or twice daily 
bandage changes until you resolve the peritonitis and can close the wound 
surgically. that's what they did in this dog. this dog did actually very 
well - but as many dogs as do well with this, as many do not. there is 
only about 50% success. the failures get SIRS as a result of the 
pancreatitis.

basic message is we do not think sx for apn is indicated 
often - only if pet has failed to respond to nonsurgical management. goal 
of sx is to debride inflammatory tissue, leave in healthy tissue, provide 
some enteral feeding access, and provide drainage. Dr Brockman has yet to 
successfully perform a total pancreatectomy and urges you not to try. he 
would try only under duress. it is difficult for animal to survive and if 
it does it needs chronic supplementation with insulin and exocrine 
enzymes, etc.

slide: attached duodenal limb of pancreas with duodenum - 
chronic pancreatitis - bile staining present near major duodenal papilla 
due to biliary obstruction. 

next condition - in Dr Washabau's lecture, 
he talked mainly about exocrine pancreatic disorders. there are also 
surgical diseases of endocrine pancreas - usually insulin secreting beta 
cell tumors, sometimes called insulinoma.
exocrine tumors in pancreas are 
very very aggressive and malignant and by the time of diagnosis, there is 
usually duodenal obstruction, erosion through gastric/duodenal wall, mets 
to liver and LNs, and it is really not a surgical case anymore b/c you 
can't help much. but we can help the ones with endocrine pancreatic 
tumors. 

the functional beta cell tumors present with hypoglycemic 
episodes causing seizures. when presented with middle/late aged animal 
with seizures and bloodwork shows hypoglycemia, consider the functional 
beta cell tumor.

to confirm dx, measure insulin level/insulin and 
glucose level together. if you have consistently low glucose/high 
insulin, strongly suspect insulin secreting tumor. now you have to rule 
out other causes of hypoglycemia, such as that associated with other 
large tumors like hepatomas which often have such high metabolic rates 
that they produce hypoglycemia, also some types of LSA produce 
hypoglycemia. so you have to do chest/abd rads, u/s, cbc, chem, u/a, 
sometimes a bone marrow aspirate. 

it's nice if you can see these tumors 
on ultrasound, but you can't always. sometimes they are very small. not 
seeing it isn't a rule out. 
these tumors are frequently small, it says 
in notes they occur more often in one limb than another but recent data 
suggests equal distribution b/w right and left limb. they may be 
microscopic and really hard to find. often throw mets to liver and local 
LNs. the point of the surgery then is to confirm your dx, and to resect 
the tumor if you can find it and get it out, and send it to biopsy. 


slides: small nodular insulinomas; large plaque of insulinoma in this 
left lateral liver lobe; small tan nodules present throughout this liver 
- metastatic beta cell tumors. presence of tumor in liver is an area of 
debate. if there, it is functional, so removing pancreatic tumor may not 
help - but it is probably worth removing the pancreatic tumor b/c it may 
take time for liver mets to become functional. usually pancreatic tumor 
is most functional at least initially. 

so look at both limbs of 
pancreas very carefully in these animals. this dog has a nodule in 
gastric limb. to remove it - and hopefully give some symptomatic relief - 
remember gastric limb is supplied via gastroepiploic artery entering at 
the tip of the limb. you can simply ligate that vessel, cut the omentum 
from around the limb, isolating the distal 1/3 of gastric limb. then 
dissect across the body of the pancreas - remember, it is lobular, so it 
is convenient to dissect across it by finding a cleft b/w lobules, and 
bluntly dissecting across ligating ducts and vessels as you go. this is 
the 'interlobular dissection' technique of pancreatic resection. some 
recent papers suggest that simply encircling the limb with a ligature and 
pulling it tight doesn't produce any more inflammation than the 
interlobular technique, but we want to minimize inflammation and Dr B 
prefers interlobular technique for that although it may be acceptable to 
use encircling ligature.

prognosis for islet cell tumors - guarded. most 
animals with beta cell tumors removed if they do not have gross liver 
mets have median dz free interval of 12 mos. if they have nonfunctional 
liver mets they may become functional in 3-5 mos so they may get 3-5 mos 
of normoglycemia. if they have functional liver mets, there are medical 
therapies to use. the main one is steroid therapy - diazoxide, which 
decreases insulin production and increases glucose utilization, is also 
used. frequent feeding of small meals is also important. that regime can 
offer useful and good quality life for a substantial time. the mainstay 
of tx though should be attempted surgical resection.

another rare tumor 
of pancreas - "gastrinoma" - gastrin secreting tumor of non-beta 
pancreatic cells. it's a rare but classic syndrome. zollinger-ellison 
syndrome - recurrent ulcers secondary to hypergastrinemia. literature 
reports that dx is often made at a point when tumor has metastasized and 
isn't amenable to resection. 

moving on to the spleen: 

spleen is, in 
contrast to pancreas, a common organ to recieve surgical attention. 
surgical tx of splenic dz is very uncomplicated. blood supply is via 
splenic artery. stomach gets part of the arterial supply for fundus via 
splenic artery branches - short gastric aa - and gastroepiploic also gets 
blood from the splenic artery. simple ligation of splenic a at base is 
ok, though, b/c of collateral circulation. some indications for splenic 
surgery:

asymmetric splenic enlargement
symmetrical splenic enlargement


slide: grossly enlarged spleen. we'd see this with things like splenic 
torsion, certain protozoal infections, lymphosarcoma, sometimes from 
barbiturate anesthetics. symmetrical splenomegaly is only a surgical dz 
if being caused by splenic torsion. perhaps as management for chronic 
lymphoma/lymphosarcoma cases or immune mediated disease like ITP as well, 
that's debatable. but splenic torsino is a gimme. 

slide: two rads to 
remind you that the spleen is very variable in radiographic appearance, 
also variable in position from right to left lateral view. right lateral 
shows us the hepatic outline nicely, and a prominent spleen just caudal 
to it, ventrally. left view has no obvious spleen on it. when you suspect 
splenic dz, you should take left, right, and vd view.

splenic torsion: 
historically, most animals with this have variable signs. nothing 
pathognomonic for it. splenic torsion often accompanies GDV - isolated 
splenic torsion is rare but can occur -t here are 41 reported cases in 
the veterinary literature, and there are 17 more we added to that last 
year.

GSD, great dane - predisposed. deep chested dogs.
signs: lethargy, 
inappetance, abdominal distension, sometimes vomiting a couple of times, 
maybe an episode of gastric tympany 

slide: abdominal distension - 
spleen pushing out body wall.

dx: usually diagnosis is difficult but 
suggested by presence of large spleen on abdominal rads, with or without 
gastric dilation. we think the best way to dx this is to do abdominal u/s 
of splenic artery - with doppler. dogs with torsion often have thrombus 
in splenic vein, no flow in splenic vein, and absent flow and thrombi in 
splenic artery. but most vets can't use that technique. 

radiographic 
features consistent with splenic torsion include free peritoneal fluid, 
presence of engorged spleen on right side of abdomen. 

slide: surgical 
case - large, black/purple spleen bulging from incision. it is rare that 
you diagnose it rapidly enough to untwist and salvage the spleen. you 
usually just take it out. here we see the splenic pedical is rotated. 
other structures get caught in that - pancreas, omentum. if you untwist 
it, you simply release toxins and thrombi from splenic vasculature into 
systemic circulation, so you want to attack the splenic pedicle in a 
healthy area, and remove. that might involve partial pancreatectomay as 
well. idea is to remove spleen and twisted pedicle en bloc.
so, that's a 
rare condition with a vague presentation, but it's pretty simple to 
treat. 

Dr Brockman always does a gastropexy while he's in there if he 
removes a splenic torsion. 

most frequent indication for splenic surgery 
is asymmetric splenic enlargement found on routine PE or found after 
spontaneous rupture with acute hemoperitoneum. most common causes: 
splenic hematoma and hemangiosarcoma. hugely different prognoses with 
these - hemangiosarcoma has a very poor px, with mets to lungs, other 
viscera, omentum, and we're still looking for good chemo therapies. we do 
the surgery on these tumor dogs to get a diagnosis and whatever. they 
often have coagulation abnormalities and stuff, but do ok through surgery 
- but median survival post op is about 3 mos. you need to do surgery to 
get the dx, though.

slide: dog went to sx after negative abdominal u/x - 
mets were present in the liver, though. so hemangiosarcoma of spleen is a 
nasty disease. often present as hemoperitoneum, and surgery is really 
just excisional biopsy and attempt to stem hemorrhage. 

not all splenic 
tumors have poor px. splenic hematoma has a fine prognosis, and so does 
splenic hyperplasia (which may be precursor to hematoma). these dogs may 
present with hemoperitoneum, more often present with big tumors you feel 
in there when you palpate them. 

slide: big black dog - weighed about 30 
lbs less after spleen was removed. this hematoma was just completely 
filling the abdomen. once it was removed, he did fine. you can't condemn 
him just on splenic mass finding. you need to do excisional biopsy. it 
could just be a hematoma and the prognosis is much better than for 
hemangiosarcom. 

other tumors in spleen - leiomyoma, leiomyosarcoma - 
malignant smooth muscle cell tumor has poor px in spleen. focal lymphoma, 
nodular lymphoma, nodular mast cell dz also present in spleen sometimes. 
but hematoma and hemangiosarcoma are the main ones.

tx for all these dzs 
is splenectomy. how do you do this? check out this slide series:

spleen 
has a hilus with vascular pedicles joining it all around visceral 
surface. as already mentioned, splenic artery serves not only spleen but 
gastric fundus, and gastroepiploic. simply ligating splenic artery and 
vein before it branches has been described. if the patient is unstable 
and you must pursue removal quickly, that's fine. but it is preferred to 
isolate the pedicles close to the splenic hilus, then isolate and divide. 
you poke a little hole in splenic mesentery, clamp on either side, cut, 
ligate with absorbable suture. there are also surgical ligating 
instruments you can use - you can place ligature clips and divide between 
them, or use a little LDS machine which ligates and divides the pedicle 
all in one go. it ligates on both sides, divides in between. the object 
here of this surgery is to have ligatures on the entire splenic hilus - 
but that is being removed, so more important are ligatures on 
mesentery/omentum that supples the vessels. so check carefully.

----


colorectal sx
david holt

he is distributing a handout with pictures of 
pyloroplasty, some other plastys, and Bilworth I on the back.

Dr Holt is 
asking for feedback on perineal hernia lecture, and today's lecture. He 
used to do it differently. He wants to know if the new way is better or 
not. 

So: colorectal surgery

anatomy: 
cecum - diverticulum of the 
proximal colon. does not communicate with ileum! there is no 
"ileocecocolic valve." the ileum connects to the colon. the cecum is an 
outpouching of colon

colon: ascending, descending, transverse segments

rectum: continuous with colon at pubic brim - caudal to pubic brim, you 
call it rectum. caudal rectum is retroperitoneal. 

signs of colorectal 
dz:
renesmus, constipation, diarrhea, melena/frank blood in stool, acute 
abdominal crisis if perforation has occurred.

dog will stand sort of 
hunched, tail tucked, acts like it has caudal abdominal pain - looks like 
dog with prostatic abscess, actually. 

melena/frank blood in stool 
common with anything from bleeding gastric ulcer to intestinal neoplasm. 
if frank blood, think more distal/caudal. 

diagnostic techniques: 

thorough abdominal palpation. a dog came in last week, straining to 
defecate, not a lot of feces in the colon of this dog. two parts of 
diagnostic evaluation were key - rectal exam revealed a scar on left side 
of anus where carcinoma of anal sac had been removed; also, in caudal 
abdomen was a big dorsal lump - a huge iliac or sublumbar LN causing 
colonic irritation/obstruction.
radiography, u/s, proctoscopy also 
important.

contrast rads: the problem here, the difficulty with doing a 
good contrast study, is twofold - one, getting animal cleaned out, if it 
is really constipated you have to do this, and two, adequate filling of 
the colon - on these slides we see the colon isn't filling well - could 
be nasty neoplasm, peristaltic wave with inadequate filling, colitis. you 
have to be sure you distend colon completely with contrast. 

abdominal 
u/s - we've been honestly - when we use u/s to dx gi lesions, we have 
been burned before. radiology puts on the probe and says "yes, there's a 
linear FB in there" and we go in and it isn't there. but u/s is very good 
at finding intestinal tumors. this slide shows a 5 cm mass with mixed 
echogenic pattern - it's a mixed leiomyosarcoma on the cecum. 

endoscopy 
is good for finding colitis, taking colonic biopsy. they did one 
proctoscopy and went through the colon and visualized the left kidney. he 
went right to surgery and did fine. this happened because diseased colon 
can be very friable.

cecal disease: uncommon. very uncommon. sometimes 
impaction, very rarely cecal intussusception as in this slide. more 
frequently than anything else in cecum we see neoplasia, usually 
leiomyosarcoma. sometimes you see melena, and you find the tumor on u/s 
and you remove it quickly. other times it grows and mets to LNs and liver 
can occur. can result in perforation. so if you do see a mass, check for 
liver mets.  would you rather have a stomach or cecal rupture? stomach. 
cecum is very contaminated, makes nasty peritonitis.

typhlectomy - cecal 
resection - or can resect part of ileum and colon and anastomose those 
together.

obstipation: dietary in dogs that eat bones, hair, other FB. 
sometimes occurs b/c defecation is painful as in dogs with perianal 
fistula or anal fistula. sometimes people adopt a cat, it gets 
constipated, people are unaware of history of pelvic fracture causing 
narrow pelvic canal - also colonic or rectal tumor, or prostatic dz can 
cause. neurologic, metabolic disease can also cause obstipation, and 
sometimes in cats we see "idiopathic megacolon" - neurologic dz? colon 
just does not contract properly. studies tend to indicate a problem with 
intracellular calcium mobilization. textbooks say it is nerve plexus 
abnormalities with myenteric plexi. our studies show problem is within 
the smooth muscle itself.

this cat came here after 6 mos of weekly 
enemas. ileum looks abnormal on VD rads...there is a healed pelvic 
fracture causing a narrow pelvic lumen. that is why this cat had 
megacolon.

tx: treat underlying cause. restore hydration/electrolyte 
blaance. warm water enemas can be used to soften fecal mass. in extreme 
cases of chronic constipation, may have to do colotomy or more often, in 
cats, colectomy.

slide: this cat came in for difficulty urinating per 
owner. ES thought it was an FUS cat. urethral cath went in no problem. so 
they did a rectal and felt the colon being displaced ventrally by a large 
LN which they then aspirated and got pus out. they removed the LN. the 
next day, the cat defecated/urinated normally. 

slides: colotomy - very 
rarely done to remove feces - use as last resort to tx chronic 
obstipation, b/c you are opening a very contaminated area. 

when do you 
decide to do colectomy? when medical mgmt like lactulose (laxative) or 
prokinetic agent such as cisapride (metoclopramide doesn't work in colon 
- only cisapride) - fails. so then you resect and anastomose ileum to 
colon, or colon to colon.

ileocolic intussusception - most common in 
young animals. look for parasites in these animals. in severe cases, 
small intestine protrudes from the anus. animals are vomiting, have 
abdominal pain, bloody stool, sausage like structures on abdominal 
palpation.

*the* diagnostic method of choice is abdominal palpation. 
this is why you have to palpate a lot of normal animals to know normal. 
if you feel a big kielbasa in there, your index of suspicion for foreign 
body or intussusception should be very high. many people will do 
exploratory laparotomy based on that finding. almost the only time you 
will be burned on that is if there are huge mesenteric LNs in there. 


slides: surgery. this is more than a two handed job. we see jejunum 
disappearing into colon here. put gentle traction on one end while 
someone gently pushes jejunum/ileum out of colon. if you get it reduced, 
assess bowel viability. look at color, pulsations in arterial arcade, 
etc. if it's questionable, resect it. 
what if you can't reduce it? then  
you have to resect and anastomose jejunum to colon. but you have a big 
difference in lumen size here. so, you have two alternatives. you can 
make incision on antimesenteric border of jejunum, to increase lumen 
size. or you can oversew part of the colon until colonic lumen 
approximates jejunal lumen. then do end to end anastomosis. 

btw, his 
slides are all messed up.

so, subtotal colectomy in cat with megacolon - 
what are we doing? by removing a big segment of colon, we remove the 
reservoir in which feces are stored. if dog wants to go out and door is 
shut, initially external anal sphincter contracts - then colon dilates, 
to accomodate fecal material. you have sphincter continence and reservoir 
continence. but in cats when you remove the colon, you remove the 
reservoir. so digesta enters the colon remnant in a pretty liquid form - 
it will pass through as liquidy or pasty stool and not sit there and get 
dehydrated. so we either resect ileocolic junction and anastomose jejunum 
to colon, or leave in short section of proximal colon, and anastomose 
colon to colon. that is what Dr H does. why? well, it's easier to pull 
down. 

in this slide, they are anastomosing jejunum to colon. what 
happens postoperatively? they've removed the colon and the ileocolic 
sphincter. so, what does that normally do? well, it prevents bacterial 
overgrowth to some degree of the small intestine. when you remove it, it 
produces bacterial overgrowth and immediate postop diarrhea.

colonic 
perforation: rare - usually only with gunshot or arrow wounds. when you 
are presented with an animal that has been shot try to find entrance and 
exit wounds and connect the dots. 

he saw two dogs that came in each 
about 3 days after being shot. wounds were on opposite sides of the 
caudal body. one dog, on rectal exam, had perforated rectum and urethra. 
total mess. dog was urinating out gunshot wound.
second dog - rectum was 
also perforated - could feel the hole.

slide: cat that presented to ES 
with mild dyspnea and apparent pain. no one saw the wound on the flank 
for about 2 hrs. cat had small wound on flank. there is a lead pellet on 
this radiograph, up by the tail. there is a loss of abdominal detail 
caudally. this cat had been shot, recently, bullet entered right side, 
went subcu, into abdomen, through kidney, intestine, duodenum, colon.


there has also been colonic perforation reported in small dogs treated 
with corticosteroids for neurological reasons. 

treat these animals for 
septic shock, do full exploratory laparotomy.

rectal prolapse: in young, 
parasitized animals most common. deworm immediately. colonic and rectal 
tumors causing straining can cause this too.
perineal hernia: post hernia 
repair
straining at parturition.

most rectal prolapse cases can be lubed 
up and manually replaced (this may require general anesthesia), and then 
place a purse string. leave some room =- for a big dog, size of your 
pinky, for little dog, size of pencil. leave in 2-3 days. we do this for 
dogs with perineal hernias post op. 

if it recurs after that - colopexy 
- ventral midline laparotomy, grasp colon, pull cranially while someone 
looks to make sure prolapse is reducing. then, make a partial thickness 
incision in colon and in lateal abdominal wall...sew them together. a 
study here compared that technique to simple suturing with no incisions 
and it worked just as well, so really you can just use proline through 
the colonic wall into the body wall,  no incising required. this is an 
effective tx to prevent prolapse recurrence.

what if you look at this 
and it looks necrotic? well, you do a resection of prolapsed tissue from 
the outside. realize this is like a sock, folded out on itself. you have 
two thicknesses of bowel wall next to each other. initially, incise only 
180 degrees, and sew the two sides together with single interrupted 
appositional sutures. then incise the second 180, sew, replace. 

rectal 
neoplasia: 
terminology is confusing: sessile polyps, adenomatous polyps, 
CIS. 
polyp: lamina propria supporting an abnormal epithelium - an 
adenoma.
carcinoma in situ (CIS): malignant cells are present, but do not 
penetrate the muscularis mucosae (the thin layer of smooth muscle b/w the 
mucosa and submucosa) into the submucosa. remember submucosa contains 
blood vessels and lymphatics - so there is much less potential for 
metastases if there is no penetration of carcinoma cells into submucosa.


polyp-cancer sequence: applies to people and to dogs
carcinomatous polyps 
- what look like benign polyps, with nests of malignant cells in them, 
have been described in dogs by Dr Seiler, 1979. some polyps had areas of 
severe epithelial atypia, sign of malignant transformation. these polyps 
were more likely to recur or become malignant. also polyps > 1 cm 
diameter were more likely to become malignant.
people with familial 
polyposis have been used to study this polyp-cancer sequence in man. many 
of the polyps sit there and remain benign adenomas, but some undergo 
malignant transformation. 

clinical signs of neoplasia: diarrhea, 
tenesmus, blood, mucus in feces; protrusion of neoplasm during 
defecation. 

slide: contrast study of colon - cranial part looks just 
fine. caudally, there is a large area of mucosal irregularity - looks 
very folded up and weird. 

diagnostic techniques: 
digital exam
contrast 
rads
chest rads for mets
colonoscopy - 30% of animals with one rectcal 
mass had multiple tumors in one study
u/s for mets
biopsy to find out 
what it is!

polyp removal:
via anus, if accessible. just grasp at base, 
divide with scissors or electrocautery if pedunculated. if not 
pedunculated, do not do this! 
if you feel something in there that is 
very broad based, and flat against the rectum, that will just not work.


rectal carcinomas - often sessile (cauliflower like) or annular (around 
the whole thing, so you feel a stricture there). mets are common via 
lymphatics, veins, or serosal implantation (everything seems thickened). 
LN, liver, lung involvement. stage before definitive surgery! look for 
mets first.

considerations in rectal/colonic surgery: 
colonic 
preparation: we talked about enemas for perineal surgery - bad idea then. 
bad idea now, too. you would rather have dry firm feces there than have 
wet slop that spills into the field. if you do enemas, do them 3 or 4 
days prior to surgery, then feed low residue diet for a few days.


antimicrobial prophylaxis - this is one area where it is ok to use them. 
there is the potential when you open the colon for substantial bacterial 
contamination. this is *prophylaxis* though. this is for when you expect 
contamination, so you give a dose of abx to get tissue levels high at 
time of sx, then d/c abx after 24 hrs.

removal of ileocolic valve - 
causes small intestine bacterial overgrowth

consider blood supply to 
colon/rectum as well.
one study showed if you remove the rectum that is 
in the middle of pelvic canal, and disrupt cranial rectal artery, 
anastomoses will not heal well. so if you operate in this area, refer to 
someone else or be really careful.

waht are the best abx? metronidazole 
is good against anaerobes. you want something good against gram negs and 
anaerobes. mefoxin (cefoxitin) is good for gram neg and anaerobes.
slide: 
removal of ileum and some colon with jenunal-colonic anastomosis. dog had 
diarrhea for 2 wks, then adapted. 
use injectable abx against anaerobes, 
proteus, and psuedomonas, and something else i iddn't catch.

gentle 
tissue handling
adequate hemostasis
keep adequate blood supply
no benefit 
of two layer closure - just use simple interrupted appositional as in 
small intestine.
drains: inhibit wound healing - if contacts surgery 
site, latex in drain inhibits healing.

fecal continence is a big 
consideration with rectal removal - experimentally, 4 cm of rectum can be 
removed, with preservation of continence. you need to preserve sensory 
fibers. if you take too much rectum you will remove too many nerve fibers 
and there will be no warning system for animal. 

anatomical 
considerations: nerves to the external anal sphincter are caudal rectal 
branch of internal pudendal, and pelvic nerve. 
distal third: pull 
through
middle: pull through or dorsal
proximal: laparotomy?

pull 
through: dissect - separate rectum from skin, leaving external sphincter 
in place, and you have to pull rectum through quite well by bluntly 
mobilizing it - make sure you get cranial to the tumor. may have to split 
the rectum. sew subcu to mucosa, and mucosa to skin. 

so first incision 
is b/w skin (inside anal sac ducts, don't transect those), freeing up the 
rectum distally. this is 360 incision. pull toward you. find your tumor. 
don't cut off before you have placed sutures. cut 180 at a time. these 
animals do very well.

Middle third if you can't get to it via pull 
through - approach dorsally. go from one ischeum up toward tailbase, down 
other side. fold anal area down, to expose rectum. here this is a big 
tumor on the outer rectal wall. this was shelled out pretty well. close 
with a drain or two.he used to put the drain over the top but now he uses 
two separate ones.

slide: dog with tumor in midrectum - same dorsal 
approach, but dissection under rectum has been done - use finger to pull 
rectum caudally by putting finger under it. then you can resect and 
anastomose proximal rectum to distal rectum. 

cranial rectal tumors - 
ventral midline laparotomy with removal of part of pubis, or go straight 
down the middle. split the pubis, caudal midline laparotomy. put 
retractor in to open pelvis.
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