| endstart medsurg 10.1.98 brockman surgery of the urogenital (ug) tract in small animals First we'll cover tumors and renal/ureteric diseases; some about renal calculi Then, next week some time we'll do an hour on surgical mgmt of bladder and urethral calculi and obstruction; then the final lecture will be a potpourri of surgical diseases of the penis. anatomy is really important. first page of notes has a diagram and discusses how different parts of the ug tract are imaged. (urethrogram, positive constrast cystogram, excretory urography) Imaging of the urinary tract - comments in notes should serve as a refresher for you from Dr E's lectures. When you think there is renal compromise, excretory urography is a poor imaging study to use, not that sensitive. renal scinitgraphy or radionucleotide imaging to determine relative renal function is probably going to be getting more common for this. so - we'll discus the kidney, ureter, bladder, and urethra note that the renal veins are most ventral and cranial of the three structures entering the hilus, the artery is b/w vein and ureter. on left hand side, renal artery is a dual structure in about 13% of dogs. this is important in 2 situations. if you are removing a kidney and you've ligated an artery, vein, and ureter and then you cut the pedicle you could cause hemorrhage! also in cats, renal transplants are being used, and when you transplant a kidney you anastamose the iliac of the recipient with the donor vessels and you need to use both donor vessels if there are two! Dr Brockman is walking around the room - he really enjoys the new mike system. Haematuria (hematuria): whole blood or rbcs in urine common sign for many of the diseases we'll discuss -from kidneys (trauma, idiopathic renal hemorrhage, capillary necrosis NSAIDs) -from bladder/ureter (uti, trauma, neoplasia) -urethra (trauma, neoplasia) -prostate (benign or malignant dz) -prepuce (male) (trauma, neoplasia, etc) -vagina (female) (neoplasia, trauma etc) so hematuria can come from anywhere in the ug tract. most of the imaging available to us is radiographic imaging. SO- radiographic renomegaly - dog and cat: causes: neoplasia hydronephrosis congenital polycystic dz acquired multicystic dz perirenal pseudocystic dz subcapsular hemorrhage or hematoma compensatory hypertrophy (PSS, unilateral agenesis) FIP pyelonephritis acute nephritis Urinary tract neoplasia: rare in general, most common site is bladder. renal: benign: hemangioma, cystadenoma malignant: renal CA, nephroblastoma (congenital), transitional cell CA, SCC biggest problem with renal tumors facing us as clinicians is the lateness during the process at which they present. If you're lucky, you'll see hematuria early on and that will be why owners bring the dog in. So if you think back to origins of hematuria, you realize this sign has a huge differential list and requires full evaluation from kidney all the way down. But realistically, most common cause of hematuria is simple bladder dz - cystitis 2ry to calculi or something. but if animal fails to respond to cystitis therapy, you have to do more thorough exam from kidney down. But, not all animal present with hematuria. some do not present til later in dz - you palpate big mass on routine PE, or owner notices cachexia, unthriftiness late in the game. workup for abdominal mass includes cbc/chem/ua, chest and abdominal rads. slide: radiographs of abdomen of a dog - there is a large abdominal soft tissue density mass taking up most of the cranial left quadrant of the abdomen. an excretory urogram shows contrast agent in the left kidney is displaced caudally (the kidney itself is displaced, that is.) slide: at surgery - left kidey is a huge tumor - renal carcinoma - treatment for which, providing there is no metastatic disease - is to remove the tumor. renal carcinoma is probably the most common renal tumor. prognosis is poor. cystic adenomas and hemangiomas have good px if removed. nephroblastoma - poor px. biggest problem is making dx early enough. chemo is not that helpful for these tumors. but, being able to dx possibly benign condition is good enough reasont o go ahead with sx - here we see 1 yr old great dane with congenital nephroblastoma which is fairly common in humans - you have to remove it quickly. in kids, they gave chemo and radiation and they live 7 or 8 years instead of one. But our patients do not even last that long. bottom line with renal tumors: rare, present typically with hematuria or palpable mass; excisional biopsy is tx of choice in absence of metastatic dz; malignancy has poor prognosis. neoplasia: ureter: transitional cell CA, leiomyoma/leiomyosarcoma. secondary renal changes due to obstructive dz may occur. also infection may occur (pyelonephritis). he hassn't seen any of these ureteric tumors as primary dz though. neoplasia: bladder - most prevalent ug tumor bladder is a storage site; urine sits there for extended periods of time, exposing epithelium to potential carcinogens for long time. malignant: transitional cell CA (most common), SCC, adenoCA, leiomyosarcoma benign: papilloma, fibroma, leiomyoma, or fibropapilloma - may see occasionally. clinically, these patients have hematuria on presentation, and signs similar to UTI. again, it's hard to justify at the outset performing extensive dx tests for first episode of hematuria, but if problems do not resolve in response to symptomatic tx for cystitis, you should do further evaluation. ua from animal with transitional cell CA will look similar to animal with uncomplicated cystitis. finding reactive trans epi cells in UA isn't a reliable diagnostic tool, b/c malignant cells can look a lot like reactive cells. so animal with nonresponsive hematuria needs a better workup. in a clinical setting, most common cause for failure to respond or transient response is the presence of calculi or some other such thing as mucus plugs or crystals in there. Bear in mind that some neoplastic dz can be going on, though. so you would do a cbc, chem, detailed u/a and think of how to look at bladder more directly to see what's going on in there. slides: positive and negative contrast cystograms of same animal that presented with recurrent hematuria, stranguria, and was a male dog from U of Melbourne. we can see a poorly distending bladder - not rounded and smooth - irregular looking surface. the cranial end is blunted - looks flat, not round - this is common predilection site for bladder neoplasia; also this is what chronic cystitis makes the bladder look like. SO this is really an equivocal finding. You would have to do a surgical exploration to see what this is. But, sometimes, contrast studies are good...more useful slide: negative contrast cystogram in young dog. you can see on the VD there are open growth plates in proximal femurs. this dog had intractable UTI, hematuria, stranguria. the lat and vd views show a very large, soft tissue mass coming from the dorsal wall of the bladder. the double contrast study clearly outlines the mass. Q - does chronic UTI predispose to bladder neoplasia? good question. maybe. perhaps in older animals. of course, bladders with tumors always have concurrent UTI so we have a chicken and egg situation. but it could contribute to oncogenesis, sure. anyway, the positive contrast in here shows us the mass really plainly. it's irregular, not smooth, in the trigone area. this dog had a congenital, very rare, botryoid tumor (grape-like) - rhabdomyosarcoma. this is very rare, and is congenital. but the point is to see the double contrast study at work. this case also demonstrates the value of u/s - these are from the same dog - proximal ureter and dilated renal pelvis are seen. the ureter is usually a mm or two mm in diameter, and this is 1.4 cm. so that's another big thing - tumors of urinary tract, if they obstruct flow, can create backpressure and disease in associated kidney - so that tumor was obstructing flow from this ureter. one problem with bladder tumors is that they often occur in the area of the trigone. this is fairly common then - they often affect ureteric outflow. this is a big problem for a surgeon b/c the trigone is the most active part of the bladder - where urine comes in, where sphincter is found, and removing trigone is associated w/high morbidity - yu have to move the ureters, you lose the sphincter, and depending on where you put the ureters or how you do your resection, you can end up with incontinent animals with chronic metabolic problems b/c you moved the urine flow into something that isn't set up for it like the colon or stomach. postmortem specimens - the kidney and ureter which were blocked by tumor are very dilated and the tumor was spreading down the proximal urethra, too. so this was bad. resection wasn't really feasible. not all bladder tumors are that bad. many are. but sometimes we can be more excited about a chance to pursue surgical therapy. as noted, preoperative evaluation will include cbc/chem/chest and abd imaging/cystoscopy if available. we might be able to dx these earlier with cystoscopic evaluations. I mean, if you were hematuric more than a few days you might want a cystoscopic evaluation! but we often let animals be hematuric for weeks before we do anythign about it. hmm. bottom line- find out what tissue diagnosis is - maybe you can do this via cystoscope but usually surgery is needed. slide: good news case. we see tumor attached to bladder mucosa by a little stalk - looks like a mushroom cloud. this is a fibroma of the bladder. resection is curative. so resection and biopsy before condemnation of the pet does make sense. slides: bad news cases- these dogs had transitional cell CAs of the bladder. on the left, we see a catheter in the ureteric orifice - which is right at the base of the tumor. the other one has a bigger tumor but it is at the cranial pole of the bladder, so you could probably excise it safely without compromising the function - you can remove as much bladder as you want, as long as you preserve the trigone, really. slide: bladder post resection of cranial 2/3 of bladder - looks like a small walnut. but trigone and ureteric orifices are present. he urinated 15-20 times a day for 3 mos, but over time bladder hyperplasia and relaxation occured and accomadated to the point where he urinated only 4 or 5 times a day. this was fine for the owners. the biggest problem with transitional cell tumors is that while margins look grossly clear, transbladder migration of cells, and implantation to other sites, is common. control of local disease is hard even when you think you've done it fine. on top of that, there doesn't seem to be any systemic or topical chemotherapeutic agent that is useful for this condition. so it is'nt a good disease to have. that said, you can get pretty good disease free intervals with surgery alone, even though you know it will ultimately return, if you can grossly get get margins, you can expect 6-12 mos before recurrence. some clients find this quite acceptable. bottom line with bladder tumors - they're rare, there are some benign forms so you have to biopsy them, when at the trigone they are nearly impossible to resect, at cranial pole if you can resect with gross margins you can get 6-12 mos disease free interval but overall, bad dz to have. neoplasia: urethra: transitional cell CA, SCC, leiomyoma/leiomyosarcoma are the main ones here. most commonly transitional cell CA - a tumor that is almost exclusively dxed in middle/late aged female dogs who present with apparent intractable UTI, hematuria, stranguria, sometimes dysuria. probably most important difference in this dz vs others is physical exam and findings. when you rectal these dogs you typically feel a thickened urethra in ventral pelvis, and so it's almost pathognomonic for this in the bitch. again, like anything else, there is a benign counterpart that justifies biopsy. chronic hyperplastic inflammatory urethritis has been occasionally reported and feels almost the same and has almost the same clinical signs. so urethroscopy and biopsy are essential. very occasionally, smooth muscle tumors are dxed - typically benign ones are discrete tumors in wall of urethra, often readily palpated on rectal exam. main diff b/w leiomyoma and SCC or trans epi is that excision is curative. the leiomyosarcoma has a worse px though. urethral neoplasia - trans cell CA, mid to late age, female dogs, present with hematuria stranguria, intractable UTI - do not forget to rectal these animals! you can't ignore these potential causes of hematuria. vaginal and preputial exams are also important. footnote here - tumors of the urethra that impede flow of urine also predispose to UTI and in extreme situations can cause complete urinary obstruction and postrenal renal failure. Congenital anomalies of the urinary tract: there are many not many are surgical -renal agenesis: sometimes dogs do not have two kidneys! right one missing... -polycystic kidneys -renal hypoplasia -ureteric ectopia - surgical condition -cystic hypoplasia -persistent urachal remnant - nidus of infxn, surgical condition sometimes -cystic agenesis - can't fix that -short urethra- causes sphincter incompetence, can be surgical (specialist) -nephroblastoma break- congenital conditions that are treated surgically: Ureteric ectopia: -ureterocoel -bladder neck -urethra -vagina -uterus -prostate NOTE: anything you need to know for the exam is in the notes. ureteric ectopia is the most common cause of urinary incontinence in juvenile animals. it is a developmental abnormality resulting in abnormal ureter position; typically instead of entering the trigone it will enter low down in the neck, in the proximal urethra, or into the vagina. occasionally will join into the uterus. in males, most common site is for it to join in prostatic urethra. can be unilateral or bilateral abnormality; in most cases it is bilateral but one side is more severely affected than the other. there's also something called ureterocoele, and this is a bit confusing - it is an intracystic dilation of a ureter - that ureter may be ectopic, or orthotopic, and if orthotopic has a pinpoint opening creating the dilation. it's common to have a diploid collecting system with these - two ureters coming from the same kidney. but usually you just see,with ectopic ureter, a normal ureter in the wrong place. breed predisposition -siberian husky, labs, goldens. typically these animals present early in life, when they've reached the point where they should be housebroken - 2-3 mos of age, the owner stops forgiving them for the accidents b/c it is a puppy, and brings it in. typically they present with urine all over tail and perineum. slide: irish wolfhound with marked discoloration of fur around this area, caused by constant urine soaking. owners typically say dogs can posture and urinate what looks like normal volume, but will also drip urine constantly. this is typical of a situation where one ureter gets urine into bladder, andthe other doesn't go into bladder at all. this is good. if one ureter is filling bladder, at least the bladder is well developed. if neither empties into bladder, bladder won't be well developed. oh, these dogs are smelly, too. they also have UTIs, almost all of them, most commonly with e.coli - ascending infection that goes up the abnormal ureter. so, if you are presented with young animal with dribbling incontinenc,e you need to do diagnostic imaging. ureteric ectopia is dxed more often in females. male dogs may have it just as often, but b/c the ectopic ureter joins the prostatic urethra, and the urethra is so long, they remain continent despite the ectopia. so, for imaging kidneys and ureters, logical study is the iv excretory urogram. this will fill kidneys and ureters with contrast. remember to do an enema first.also do a negative contrast cystogram if possible so you can see the trigone better. slides: excretory urogram showing modestly dilated left renal pelvis, severely dilated left ureter, and dilation at the ureteric vesicular junction. we can't really see where the ureter is going into the bladder though. the right kidney looks fine, and right ureter looks fine. we can't really see if it goes to trigone and makes J hook - at least, I can't see. butthis hydronephrosis and hydroureter on the other side is blatant. probably b/c the ureter is going through the urethral sphincter mechanism. what now? we could do fluoroscopy and watch contrast go down the ureter and see where it enters the bladder; we could do another contrast study - retrograde vaginal urogram - foley in vagina - contrast is injected to fill the vaginal vestibule and vagina, and also fills the urethra and bladder in retrograde fashion. and we see here that the ureter is filling with contrast as it leave the urethra in the proximal 1/3 of urethra. shouldn't be there. in the other dog, we see an ectopic ureter filling in retrograde fashion from the vagina. retrograde vaginal urography is very useful for dx of this problem. surgical problem is this - ureter comes down into bladder typically joins it in a normal place, but then tunnels submucosally down the urethra. we have to create a neostoma, if you will, in the trigone area, and somehow ablate or ligate or remove the distal portion of the ectopic ureter. or, if the ureter totally bypassed bladder, you reimplant it into the bladder. in dogs, this is very uncommon - very rare. dr brockman has not ever seen one. intramural ectopic ureter is more common. neostoma and ligation of distal portion is the tx - but there are also abnormalities of kidney and ureter that might prevent success. slide: VD of abdomen of dog. suppsed to be neg contrast cystogram - but is pneumoureterogram - hugely dilated ureter and renal pelvis are obviously so severe that surgical movement of ureter isn't going to help that much - should probably remove the affected kidney and ureter to prevent recurrent pyelonephritis. slide: husky who presented with massive cystic abdominal growth. excretory urogram shows hugely dilated ureter on one side, and a HUGE kidney occupying entire ventral abdomen. bilat ureteric ectopia was present - one kidney had undergone irreversible hydronephrosis to a huge degree. removed that. the other one was moved over and hopefully since hydronephrosis was less severe was able to function. we know he lasted at least 5 years postop :) slides: intraoperative examples of ureteric ectopia - when approaching trigone, btw, we always make ventral cystotomy. stay sutures are used to hold bladder open relatively atraumatically. we can see a dilated intramural tunneling of the ureter (well, he sees it, i don't) tx is to open this tunneling thing in the trigone, suture it open, and place sutures distal to the opening, to ablate/occlude the distal portion of the tunneling ectopic ureter. can do this bilaterally or unilaterally as needed. However, sorting the plumbing out is just part of the story. dogs considered favorable for surgery (no irreversible renal changes, free of infection) success rate is still only about 50% - half stay incontinent. why? these animals often have congenital abnormalities of the urethral as well - the length and sphincter may be affected. most failures are incontinent due to sphincter problems. however, you can't assume b/c surgery failed that this is why. you have to work it up. slide: case in point to explain the motives for some of the more recent surgical developments - we have found that the intramural tunneling part of ureter sometimes opens back up, even after we suture it closed. this retrograde vaginal urethrogram shows us the intramural ectopic ureter connecting and communicating with the bladder again. so then you would want to close that again. vesicourethral fistulas, etc. also treat surgically. so, now, some people doing sx on these dogs do another technique that is more effective than just ligating the intramural tunneling part - here, they create the neostoma in trigone as before, but bladder is opened all the way down the urethra so also a ventral urethrotomy - to dissect out this intramural ureter all the way down. if you completely remove it, then you can suture the neostoma and repair your trough you've created, and hopefully you end up with a small defect in mucosa and no potential for future problems...right? right? this seems like you should be ok - you've got no ectopic ureter left in there. preliminary investigations suggest a higher continence rate. but only reduced incontinence from 50% to about 30% - the rest have a sphincter problem. the intramural portion, btw, is submucosal - your surgery shouldn't be involving the muscle of the trigone - but there will be some inflammation, which might also affect the sphincter mechanism, so you know - we think these animals have a congenital sphincter problem but maybe some also get that from surgery? this is again the most common cause of juvenile incontinence. you have to treat the infection that is usually present before sx. at sx, you remove the ureter and kidney if severely damaged. the surgical tx is "fun" but quite delicate, and success rate in 60-65% area isn't as high as we'd like. don't forget -this isn't just seen in bitches, also in male dog. final comment about patent urachus/persistent urachal remnant - slide: bladder of dog with ectopic ureters and an obvious urachal remnant - embryonic structure attaching bladder to umbilicus - what happens is it is a nidus of infection - if UTI occurs, this won't clear up. the cranial part of bladder is a fairly weak area anyway, and infxn may create a radiographic abnormality here so sometimes you have a diagnostic chicken/egg situation, which came first, infection or diverticulum? but often we do see this diverticulum or remnant, and surgical resection with submission for culture and biopsy will generally cure these animals that have persistent problems. Urinary tract trauma in dog and cat: persistent hematuria following trauma: -general circulatory stability -abdominal palpation - not that useful; can sometimes palpate full bladder in the presence of complete urethral avulsion. don't fall into a trap here. -urinary catheterization - if you catheterize bladder and get a lot of normal urine that's pretty clear; small amounts of blood or bloody urine aren't that useful. you could be feeding your cath into a pocket of accumulated urine, or past a urethral tear or something. -plain film radiography - helps you see free peritoneal fluid but you do not know what the fluid is. -cbc/chem usually reflect hypovolemia/blood loss. serial testing for renal parameters will help you know if there is leaking of urine into body cavity -abdominocentesis - this is useful. look for K+ and creat content and compare to serum. -contrast rads - best way to determine status of urinary tract. with trauma patients, of course, you have to stabilize the animal and keep it alive and so forth prior to dealing with urinary tract disease. pulmonary contusions and hemorrhage will kill the animal before the urinary problem. this can wait 12 hrs or so. but, during stabilization of patient you will evaluate urinary tract using above methods. sometimes we can't get so far as performing rads. kidneys after blunt trauma can be so damaged that the uncontrollable hemorrhage into peritoneal cavity requires immediate surgery. if you explore an abdomen b/c of uncontrolled hemorrhage into peritoneal cavity, look at kidney, spleen,liver, intestines, all these things can be bleeding. slides: kidney traumatized - huge hematomas, clots, etc - this dog exsanguinated through it. slide: cat that was shot with a bb gun - bb entered chest, went through into kidney, and lodged in the base of the tail. they removed the kidney. other option - place sutures in capsule at entry and exit sites and hope for the best. this was a big ordeal - hemorrhage in thorax from tears in pulmonary vessels, lots of peritoneal hemorrhage, cat didn't make it. point: when there is so much kidney damage that the patient is bleedingout, prognosis is very very very very grave. tricks you can try: if you have a kidney with one damaged pole, place mattress sutures for hemostasis. resect the damaged area and suture omentum onto exposed pole to create a seal. probably important to suture renal pelvis if you breach it to avoid urine leakage. occasionally, dogs after blunt abdominal trauma sustain ureteric avulsion - rare. this dog presented to ES b/c of "running away and coming home lame with big perineal swelling" rads show large, soft tissue swelling in dorsal/caudal/lumbar area. pathognomonic for retroperitoneal fluid leakage - blood or urine. this space is continuous with pelvic space. the fluid is urine leaking from ureteric avulsion. excretory urogram shows us a displaced left kidney, normal ureter- and right kidney with contrast coming out of it to the level of L3 and then spreading through retroperitoneal space. tx: primary repair of ureter (very hard without magnification) or ureteronephrectomy (tx of choice unless you have magnification experience!) more commonly - pelvic trauma and urethral disruption - pos contrast urethrogram of this male dog shows us the bladder full of urine and a little contrast, but urethra is avulsed from prostate area and contrast is going into abdomen. surgical repair is indicated. basic principles are these: you want to approach the urethra as for any other traumatic condition and debride any devitalized tissue; then reanastomose by placing a small number of very fine reabsorbable sutures - 5-0 PDS - do not create a water tight seal (or try to) b/c you will use too much suture and cause a stricture. gently appose the tissue ends, and provide temporary urinary diversion - tube cystostomy - place foley into bladder to drain urine while urethra heals. in the past, people woudl have talked about placing a transurethral bladder catheter - but it's been shown that red rubber or silicone caths crossing the anastomosis increases the risk of stricture formation. thus endeth the comments about UT trauma. bladder rupture, btw, is treated clearly by surgical debridement and suturing. we'll talk about that in next hour. first we'll discuss nephrectomy. slides: left kidney surgical exposure - ventral midline laparotomy was done, you are on left side of dog. reflect perirenal fat by making small incision in fascia and exposing renal hilus. should be able to see this- kidney is being reflected up and we see ureter (small) artery (big - goes to aorta) and vein. first thing people do is ligate artery - there is discussion over doing artery vs vein first - some say vein first will reduce circulating tumor cells, if you have a tumor. but this fills kidney with blood and makes it friable and bloody. probably best to do artery first then vein. can preplace sutures, do them both at same time. ligate artery as close to the aorta as possible, to vvoid a stump where a thrombus could form. double ligate artery and divide between ligatures. then do the vein. then do the ureter - ligate at the trigone so as not to leave a nidus for infection - double ligate and divide - now, use gentle traction to get kidney out. that's it. | |
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