16. urinary surgery 2

types of uroliths

• calcium oxalate

  • most common in kidneys/ureters of cats

• struvite

  • form with elevated pH and infection (usually bladder)

• urate / ammonium biurate

• cystine — intact male dogs

which types of urinary stone are radiopaque?

calcium oxalate and struvite (others are NOT — may have obstructive stones not visible on x-rays)

workup for urolithiasis

• CBC / chem

  • may be normal

  • azotemia means other kidney is diseased (by something) too

  • anemia common

• culture urine (often negative if stones isolated to kidneys)

  • concurrent UTI ~32%

• image entire urinary tract

medical management of struvite stones

• appropriate if not obstructive

• can dissolve over 2-6 wks

• treat with appropriate antibiotics

• diet or medication to promote acidic or neutral urine pH

medical management of ureteral stones

• IV fluids (balanced isotonic crystalloids)

• osmotic diuretics (mannitol)

• alpha-receptor antagonists (prazosin / tamsulosin)

• ureteral smooth muscle relaxants (glucagon / amitryptyline / amlodipine)

• antibiotics

• variable efficacy reported

indications for surgical removal of kidney / ureteral stones

• if any of the following: azotemia, hematuria, pain, infection, obstruction

• creatine is not sensitive or specific for obstruction; ureteral dilation is found on imaging!

ectopic ureters diagnosis

• rule out other disease (survey rads, urinalysis, and culture)

• ultrasound (rule out other problems)

• contrast-enhanced rads

  • excretory urography

  • vaginocystography

  • contrast CT scan (most sensitive)

• cystoscopy

  • ± laser ablation

intramural vs. extramural ectopic ureters

• intramural — common

  • ureter enters trigone → continues to travel in wall, empties into urethra

  • externally won’t see that it’s ectopic

• extramural — uncommon

  • ureter enters past trigone

urinary bladder diagnostics

• urinalysis — cytology & culture

• imaging

  • radiographs

  • contrast radiographs

  • U/S

  • contrast-enhanced CT

• cystoscopy

• catheter biopsy

urinary bladder — operating technique (up to closure)

• prep vulva/prepuce

• incise to pubis

• pack off abdomen

• incise avascular region

  • dorsal or ventral

  • ventral recommended

• avoid tissue trauma

  • use stay sutures (not forceps)

  • cold saline for hemostasis (not electrocautery)

  • saline and suction to increase visibility (not gauze sponges)

• be conscious of ureteral openings

urinary bladder — closure

• must engage submucosa — holding layer

• 3-0 to 5-0

• rapidly absorbing suture (vicryl, monocryl, biosyn, etc…)

  • avoid long acting absorbable or non-absorbable — can be nidus for infection/stones; long-term source of irritation

• 1 or 2 layers

• appositional vs. inverting

• complications: hematuria, uroabdomen, UTI, stones

surgical removal of cystic calculi

• struvite or calcium oxalate

• retrieval

• pre-op radiographs immediately before

• pass catheter normograde & retrograde to ensure all removed

  • always prep vulva / prepuce

• post-op radiographs

• always submit stones for analysis

• always take sample of bladder mucosa for culture

indications for partial cystectomy

• patent urachus / urachal diverticulum

• neoplasia / polyp

• trauma / necrosis

• avoid trigone

  • can reimplant ureters if necessary

• close the same as cystotomy

congenital bladder surgical conditions

• vesicourachal diverticulae

• patent urachus — communication between bladder and allantoic sac

• contrast cystography to diagnose

• resect abnormal tissue & close bladder

urinary bladder trauma — symptoms & metabolic changes

symptoms

• hematuria, anuria, dysuria, abdominal bruising, abdominal pain, systemically ill

metabolic changes

• azotemia, dehydration, metabolic acidosis, hyperkalemia

urinary bladder trauma — diagnostics

• abdominocentesis

  • urea and creatinine (> serum creatinine), hematocrit, TP, cytology

• cystourethrogram or excretory urography to determine location

urinary bladder trauma — treatment

• supportive care, cystostomy tube, peritoneal drain ± surgery

• must be stabilized before surgery (fluids, remove the urine, ± dialysis, etc.)

• resect nonviable tissue & close

• consider wrapping with omentum

urinary bladder neoplasia diagnostics

• imaging (U/S ± CT)

• catheter biopsy

  • **do not aspirate through body wall — TCC has high rate of seeding with FNA

• thoracic rads

urinary bladder neoplasia treatment

• ± surgery, chemotherapy, NSAIDs, radiation

• palliation: urethral stent or cystotomy tube

• TCC = poor prognosis (other tumors may do well with excision)

indications for cystotomy tube

• stabilize (lower urinary obstruction)

• bladder or urethral trauma

• obstructive disease (neoplasia) — salvage option

• neurogenic bladder atony

cystotomy tube technique

• paramedian position

• purse-string suture in bladder wall

• catheter passes through purse-string into bladder

• cystopexy (suture to body wall)

cystostomy tube complications

• urinary tract infection

  • culture and treat intermittently

  • continuous antibiotics promote resistant bacteria

• cystic calculi