Theriogenology VMED 5361


Fall 2003

Dr. J. Davidson


Surgical Conditions of the Ovaries. 2

Congenital Anomalies 2

Ovarian agenesis 2

Ovarian hypoplasia.......... 2

Supernumerary ovaries 2

True hermaphroditism 2

Pseudohermaphroditism..... 2

Ovarian Cysts...... 2

Follicular cysts... 2

Luteal cysts... 3

Parovarian cysts 3

Ovarian Neoplasia 3

Surgical Conditions of the Uterus... 4

Pyometra 4

Hydrometra/Mucometra 5

Subinvolution of Placental Sites....... 5

Metritis.... 5

Uterine Torsion... 5

Uterine Prolapse. 5

Uterine Rupture... 6

Uterine Neoplasia 6

Common Surgeries of the Uterus... 6

Ovariohysterectomy (OHE or OVH)....... 6

Indications.......... 6

Preoperative evaluation............ 6

Complications..... 7

Cesarean Section... 7

Indications.......... 7

Preoperative care 7

Anesthetic protocols............ 8

Surgical technique............ 8

Surgical Conditions of the Vagina, Vestibule, and Vulva........... 9

Congenital Abnormalities.............. 9

Segmental Vaginal Aplasia or Hypoplasia.......... 9

Persistent Hymen. 9

Rectovaginal/Rectovestibular Fistula 10

Acquired Abnormalities............ 10

Vaginal Edema (vaginal hyperplasia)....... 10

Vaginal Prolapse.......... 10

Vaginal Neoplasia.......... 11

Vulvar Hypertrophy...... 11

Vulvar Hypoplasia / Infantile Vulva. 11

Mammary Neoplasia. 12

List of textbook references 13




·         Know the signs and diagnostic findings for ovarian neoplasia

·         Know how to diagnose and treat pyometra.

·         Understand how the signs and diagnostic findings of metritis differ from pyometra.

·         Know how to diagnose and treat uterine prolapse.

·         Know the indications for and complications of ovariohysterectomy.

·         Know the indications for and complications of cesarean section.

·         Understand the surgical treatment options for persistent hymen.

·         Understand how the signs of vaginal edema, vaginal prolapse, and vaginal neoplasia differ.

·         Be familiar with the 3 main vaginal neoplasias.

·         Understand how the behavior of  mammary neoplasia differs between the dog and cat.

·         Be familiar with the various treatment options for mammary neoplasia.

Note: References to textbook illustrations have been provided and are marked by “ILL”, for those who are interested. Use of these references is optional and only provided for your convenience. A list of textbook references is provided at the end of these notes. If you are planning to work with small animals, you should consider owning at least one of these textbooks as a reference.


Surgical Conditions of the Ovaries


Congenital Anomalies


Ovarian agenesis

ovaries absent unilaterally or bilaterally.

Ovarian hypoplasia

underdeveloped ovaries.

Supernumerary ovaries

True hermaphroditism

both ovarian and testicular tissue in the same individual.


the external genitalia is of the opposite sex as the gonads


may be no overt problems        

Surgical Treatment

Remove gonads.  May do cosmetic surgery on external genitalia.


Ovarian Cysts

Follicular cysts

most common type. single or multiple. may develop after incomplete removal at spay. 


 persistent heat, mammary hyperplasia, or none. 


visualizing cyst at laparoscopy or laparotomy

Surgical Treatment:

 excision or rupture of cyst (or hormonal treatment) ovariohysterectomy (OHE)


Luteal cysts

release progesterone.  usually multiple


persistent anestrus, cystic endometrial hyperplasia, or pyometra. 

Surgical Treatment:

excise cyst or ovary (or hormonal treatment) OHE


Parovarian cysts

usually an incidental finding during routine spay.


Ovarian Neoplasia 


more frequent in older, nulliparous bitches. 


- if increased production of  progesterone result is cystic endometrial hyperplasia or pyometra. 

- if increased production of estrogen result is persistent heat, aplastic anemia.

- enlarged abdomen due to large tumor or to ascites from peritoneal  metastasis.

- may have neurologic abnormalities if metastasis to CNS


physical/neurologic exam (palpate mass in abdomen), vaginal cytology (cornification due to estrogen), serum progesterone (>2 ng/ml), CBC +/- bone marrow biopsy (anemia), abdominal and thoracic radiographs (primary tumor and/or metastasis), abdominal ultrasound, biopsy

Surgical Treatment

OHE.  if young, breeding dog with large calcified tumor (suspect teratoma), you may just excise the affected ovary.


good if benign and no aplastic anemia.  poor if metastasis or bone marrow suppression.

Adenoma/Cystadenoma  - may cause increased progesterone

Adenocarcinoma/Cystadenocarcinoma - most common ovarian tumor in bitches.  may have metastasis to abdominal organs and lungs causing ascites and hydrothorax

Granulosa cell tumor - increased estrogen or progesterone. most common ovarian tumor in queens.  may metastasize to abdominal organs or CNS. tends to be benign in bitch and malignant in queen.

Dysgerminoma - rarely cause signs. may metastasize to adjacent organs.   

Teratoma (Dermoid cyst) - may be asymptomatic or present for suspected pregnancy.  may be calcified.

Teratocarcinoma - often calcified. metastasizes regionally to bone so may be lame.


Surgical Conditions of the Uterus



Pyometra is inflammation of the uterus.  Etiopathogenesis is not clear, but progesterone plays a key role by increasing uterine secretions, decreasing contractions, and closing the cervix.  (Repeated estrous cycles can lead to cystic endometrial hyperplasia (CEH). However, pyometra can occur without CEH.)The uterus becomes more susceptible to infection - E. coli the most common, but other aerobes and anaerobes can also be isolated.


anorexia, PU/PD, depression, +/- vaginal discharge, vomiting, diarrhea, shock.


Signalment and history - usually occurs in bitches >6 yrs old, and usually within  8 weeks of estrus.                     

Physical exam - temperature may be normal. purulent or sanguineous vaginal discharge if cervix is open (open pyometra), no discharge if cervix is closed (closed pyometra).  +/- palpate enlarged uterus.

Lab data – may be normal, but usually have leukocytosis +/- left shift and hyperglobulinemia which indicate inflammation.  may have hypoalbuminemia due to decreased production, decreased intake, or loss in utero.  may have nonregenerative anemia due to loss of RBC's into lumen and toxic depression of production. may have prerenal azotemia.  may have low urine specific gravity - (how pyometra affects the kidneys is not clear.  one theory is that E. coli endotoxin or other toxins affect the ability of the renal tubules to reabsorb water. Antigen-antibody complex glomerulopathy? Direct effect of endotoxins?).  may  have urinary tract infection.  SAP can be elevated. can have metabolic acidosis.

Diagnostic imaging -  may see tubular soft tissue density on survey abdominal films.  radiographs may be nondiagnostic, but can usually identify fluid-filled tubular structure on abdominal ultrasound.

[ILL. Hedlund (2002) Fig 28-15 radiograph]

Surgical Treatment

broad spectrum antibiotics & fluid therapy

Ovariohysterectomy - Same as a routine OHE but the uterus is more friable (and may be filled with pus), so pack it off with laparotomy sponges to prevent contamination.  Culture the uterus!  Don't leave any uterine body in the dog.  Lavage the uterine stump with sterile saline and consider oversewing the end of the stump if mucosa is protruding - this can be done with interrupted Lembert sutures or a Parker-Kerr oversew. Disadvantages of oversewing are the potential for uterine stump granuloma or abscess.

Post op care:  Continue antibiotics for 7-10 days based on culture and sensitivity results.


usually good.  If death occurs, it is usually due to septicemia.    

Medical Treatment

Not recommended.  Can be attempted if cervix is open and dog is a valuable breeding bitch.  Use antibiotics and PGF2a (not approved for use in dogs) to contract the myometrium, relax the cervix, and lyse the CL. (antibiotics can resolve bacterial infection, but medication does not alter any underlying CEH.)  Potential side effects include restlessness, salivation, vomiting, defecation, forcing pus through the oviducts into the peritoneal cavity, and uterine rupture.  Recurrence of pyometra is likely so she should be bred at the next estrus.



accumulation of sterile fluid in the uterus - uncommon and usually an incidental finding.


Subinvolution of Placental Sites

 Placental sites do not degenerate and serosanguineous drainage is noted 7-12 weeks post partum.  It usually occurs in dogs <2 1/2 yrs old, with first or second litter.


anemia due to hemorrhage, palpate enlarged uterine horns. R/O metritis, vaginitis, neoplasia.


OHE to stop blood loss. Spontaneous recovery is common.  Medical management may be tried using ergonovine, but success varies.



 Similar to pyometra but metritis usually occurs postpartum and is associated with dystocia, obstetrical manipulation, or retained fetus or placenta.


anorexia, depression, vomiting, vaginal discharge, fever, mastitis.  (Differs from pyometra in that there is no PU/PD.)


Signalment and history - usually occurs immediately postpartum.

Physical exam - fever.  malodorous, mucopurulent vaginal discharge

Lab data - usually have leukocytosis with degenerative left shift.  see degenerate PMNs and bacteria on cytology of the discharge.

Surgical Treatment

OHE is recommended if not a breeding animal or if she has severe systemic signs. Perform surgery and post op care as for pyometra.       

Medical Treatment

 consider if she is not too sick and is a breeding animal. Use systemic antibiotics and drain the uterus daily.  A soft rubber catheter can be passed if the cervix is dilated.  If a catheter cannot be passed, the uterus can be drained by laparotomy and hysterotomy.  You can also use ergonovine maleate or PGF2α as for pyometra.


Uterine Torsion

Usually occurs in a gravid uterus, etiology unknown.


acute abdominal pain, vomiting, severe depression and collapse, shock.


supposedly can feel rotation on vaginal exam, but more likely to be diagnosed on exploratory.


OHE +/- cesarean section.  Do not derotate the uterus.


High mortality, especially if in DIC or peritonitis due to rupture.


Uterine Prolapse 


Usually occurs at labor or within 48 hrs.   


one or two tubular masses protruding from vulva. May be in shock if intra-abdominal bleeding.


- If uterus looks healthy, flush with warm saline and lubricate with a water soluble jelly.  Gently manipulate uterus to manually reduce. Recurrence is rare. 

- If manual reduction fails or the uterus is necrotic, amputate the uterus.  A smooth, cylindrical object is placed in the uterine lumen and 4 stay sutures are placed at equidistant points around the prolapsed uterus.  Incise through all layers to the inserted object, one quadrant at a time.  Immediately after incising one quadrant, anastomose the inner and outer layers of the prolapsed uterus with simple interrupted absorbable suture before incising the next quadrant.

- If uterus is replaced but uterine tissue is damaged or there is internal bleeding, may need OHE.


Uterine Rupture

May occur secondary to pregnancy or pyometra.  Can cause peritonitis.  If the tear is sutured, it may recur or fibrose, so do OHE or unilateral OHE.


Uterine Neoplasia


Leiomyoma is the most common canine uterine neoplasia.  Adenocarcinoma is the most common feline uterine tumor. It may metastasis regionally, or to lungs, brain, or eyes.


depends on tumor type, size and pattern of metastasis.  Illness is usually related to metastatic disease.


usually at OHE or necropsy.  May find in patient suspected of having pyometra.


OHE after checking for metastasis.  Can try chemotherapy  for metastatic dz.


good for benign tumors.  poor for malignant tumors.


Common Surgeries of the Uterus


Ovariohysterectomy (OHE or OVH)


·         elective sterilization. This is recommended before 1st estrus to reduce risk of mammary neoplasia. May be done as early as 7 weeks in spay-neuter programs designed to reduce pet overpopulation problems. Main points to remember for early spay are to avoid hypothermia and hypoglycemia.

·         ovarian dz (cysts or neoplasia)

·         uterine disease (pyometra, subinvolution, metritis, torsion, rupture, neoplasia)

·         diseases related to hormone production (prevent mammary tumors, prevent vaginal edema, vaginal prolapse, help control unregulated diabetics)


Preoperative evaluation

·         physical exam

·         extent of diagnostic evaluation is related to animal's age and reason for surgery






during surgery or post operative (bleed into abdomen or vagina). More potential problems if OHE performed during estrus.

Recurrent estrus

due to incomplete ovary removal – e.g. if ligature placement is incorrect. If ovarian tissue is accidentally dropped into the abdomen it can revascularize or reimplant and be functional. Can diagnose by identifying cornified vaginal epithelial cells and/or increased serum progesterone (>2 ng/ml). Explore while there are signs of estrus when the tissue is enlarged and easier to find.

Uterine stump infection

especially if progesterone is present from ovary or exogenous source

Uterine or ovarian stump granuloma with or without fistulous tracts

 may occur secondary to braided nonabsorbable suture (Vetafil, silk)

Ligation of ureter 

will develop unilateral hydronephrosis.  If you ligate both ureters, the dog will go into anuric renal failure.  The ureters are usually damaged so they must be transected and reimplanted into the bladder. 

Urinary incontinence

estrogen responsive incontinence may occur and can be treated with diethlystilbesterol or phenylpropanolamine. No difference in incidence of this between animals spayed in an early spay-neuter program as compared to those spayed later.

Eunuchoid syndrome

decreased aggression and stamina.? Not proven

Weight gain

not a problem if diet and exercise are regulated.

Infantile vulva

Can occur  for animals who have surgery at 7 weeks of age, but generally has no clinical significance. (Males castrated young will also have smaller penis than those castrated later.)


Cesarean Section


·         complete primary uterine inertia (dachshunds and Scotties)

·         incomplete primary uterine inertia refractory to medical therapy

·         secondary uterine inertia (St. Bernards)

·         relative or absolute fetal oversize (brachycephalic fetus tend to have large head/shoulders)

·         anatomic abnormalities of pelvic canal (old pelvic fractures)

·         uncorrectable fetal malpresentation (transverse presentation)

·         fetal death with putrefaction (greyhounds)

·         toxemia (fetal death, uterine torsion, uterine rupture)


Preoperative care

warm IV fluids - correct any deficits prior to anesthesia, if possible (hypoglycemia, hypocalcemia)

antibiotics - if uterine infection, dead fetus, or manual manipulation

steroids - if septic shock

clip and scrub surgical site prior to anesthesia  - if possible without exciting bitch. 

surgery table should be warm and level  (doesn't need to be tilted)

final scrub under anesthesia

Anesthetic protocols

want optimum analgesia and immobilization of bitch with minimal compromise of fetuses.

Check your anesthesia notes for details on this. From a surgical standpoint, you want to be very efficient – so plan ahead and keep moving!


Surgical technique


ventral midline abdominal.  (can also use flank approach to avoid mammary glands, but is more vascular, less familiar, and less exposure.)  pack off uterus with laparotomy sponges.



longitudinal incision through avascular region of uterine body.  Gently advance fetus to incision, open amniotic sac, pull out puppy, clamp umbilical cord, place puppy on sterile towel and hand to nonsterile assistant.  Use gentle traction to remove placenta.  If it's firmly adhered, leave it.  Check to be sure uterus is empty of fetuses and placentas.  Can give oxytocin to stimulate uterine contractions and to help control bleeding.  close uterus with 1 or 2 layers, using continuous inverting suture pattern (Cushings or Lembert) with absorbable suture.

[ILL. Hedlund (2002) Fig 28-7 and 28-8 photos]

[ILL. Gilson (2003) Fig 101-1, 101-2, 101-3 drawings]

[ILL. Probst (1998) Fig 30-9 thru 30-13 drawings]


en bloc ovariohysterectomy:

This is an alternative to hysterotomy if the animal is to be spayed as well. Isolate the ovarian pedicles. break down the broad ligament between the ovary and cervix on both sides of the uterus. manipulate any fetuses from the cervix and vagina into the uterine body. Double clamp both ovarian pedicles and the uterus just cranial to the cervix. cut between the clamps and pass the ovaries and uterus to a team of nonsterile assistants, who can immediately open the uterus and resuscitate the neonates. double ligate the pedicles. The advantages of this procedure are that there is less chance for contamination by the uterine fluids, and it shortens the anesthesia time. A potential disadvantage is that you need enough assistants to resuscitate the entire litter at once.

[ILL. Mullen (1998) Fig 30-14 thru 30-17 drawings]



obtain sample for culture and sensitivity followed by abdominal lavage if any spillage from uterus.  routine abdominal closure.


neonatal resuscitation:  

clean membranes and fluid from oral cavity and nostrils by swab or suction. can swing body and head in downward arc to clear fluid from airway. rub neonate with towel to stimulate respiration and to  dry. check for heartbeat and breathing (can give atropine or doxapram sublingual or by umbilical vein). give few drops of 50% glucose if not responding well. can give naloxone if bitch had narcotics. ligate umbilical cord if it bleeds when clamp is removed. keep warm. check for congenital defects.          




post operative care: 

clean incision. observe for hypothermia, depression, shock, excess vaginal bleeding. put puppies with bitch as soon as she is awake and watch for behavioral problems. puppies need colostrum and nursing stimulates oxytocin to promote uterine contraction. send home ASAP.



hypovolemia/hypotension - due to blood loss, shock, anesthesia. treat with fluids and transfusions as needed.

uterine hemorrhage - check for coagulopathies. control with oxytocin or ergonovine maleate. transfuse if necessary.  may need OHE.

peritonitis - due to break in technique or sepsis

uterine scarring and adhesions - by third C sect may have decreased litter size and difficult to exteriorize the uterus. if the horn was incised, it may scar and prevent further placentation or cause abnormal fetal development.

agalactia - usually milk within 24 hrs.  oxytocin will stimulate milk let-down but not milk production.

prolapsed uterus

mastitis - enlarged, hot, painful mammary gland, fever, anorexia. Tx warm soaks.

retained placenta - will usually come out on its own. if not, may lead to septic metritis.

eclampsia - see trembling, weakness, convulsions, fever 2-4 wks post partum. usually small breeds with large litters. Tx Ca gluconate and vitamin D

subinvolution of placental sites - serosanguineous discharge. treat as for hemorrhage.


Surgical Conditions of the Vagina, Vestibule, and Vulva


Congenital Abnormalities


Segmental Vaginal Aplasia or Hypoplasia

segmental vaginal aplasia - complete occlusion and retention of uterine fluids

vaginal hypoplasia - partial occlusion


asymptomatic, vaginitis, inability to tie


digital palpation, vaginoscopy, vaginography

Treatment options

- breeding bitch- can resect caudal and midvaginal strictures. incise longitudinally and suture transversely.

- nonbreeding symptomatic - OHE or vaginectomy

- nonbreeding asymptomatic - no Tx


Persistent Hymen

vertical septum or annular stricture at vestibulovaginal junction


difficulty breeding, chronic vaginitis, urine pooling, mucometra


palpation, vaginogram, vaginoscopy



- episiotomy - incise from dorsal vulvar commissure toward anus along median raphe. incise fascia and vulvar muscles, then mucosa. place urinary catheter.  resect septum.  close episiotomy in 3 layers.

- abdominal approach is needed if septum is > 2 cm cranial.

- vaginectomy is indicated if the stricture is cranial, if urine pools after the septum has been removed, or if surgical relief of the stricture was unsuccessful.


guarded if surgery site strictures post operatively

[ILL. Hedlund (2002) Fig 28-9 drawing of episiotomy]

[ILL. Manfra Marretta (1998) Fig 31-8 thru 31-11drawing of episiotomy]

[ILL. Wykes (2003) Fig 99-2 photo of persistent hymen]


Rectovaginal/Rectovestibular Fistula

often associated with imperforate anus. if large fistula - do okay until start on solid food, then may develop megacolon.    


feces from vulva or urine from anus. vaginitis, cystitis, frequent urination


barium enema or barium in vagina


ligate or oversew fistula. reconstruct wall.


incontinence. especially if had imperforate anus.

[ILL. Wykes (2003) Fig 99-5 drawing]


Acquired Abnormalities

Vaginal Edema (vaginal hyperplasia)

occurs during follicular phase, usually during first estrus and may recur. may also recur at parturition and cause problems.  brachycephalics are predisposed.


mass cranial to urethral papilla, may protrude through vulvar labia. can desiccate or become traumatized. urethra is easily catheterized.

Treatment options

-  if mild, keep moist with soluble jelly until it reduces during diestrus. megestrol acetate (progesterone) to prevent, but also prevents ovulation.

- GnRH - can cause cysts.

- surgical resection - episiotomy and resect at base, close vaginal mucosa. may recur at next heat

- OHE - Tx of choice if not a breeding bitch

[ILL. Wykes (2003) Fig 99-6 drawing]

[ILL. Pettit (1998) Fig 31-1 drawing]


Vaginal Prolapse


may be hereditary. brachycephalics are predisposed. may precede uterine prolapse. occurs during periods of increased estrogen. rare during pregnancy


donut shaped eversion of vagina, may see urethral papilla

Treatment options

-  if mild, will spontaneously regress during diestrus - keep moist

- replace. may suture uterus or broad ligament to abdominal wall, or suture labia

- resect devitalized tissue (first do episiotomy and place urinary catheter)

- OHE is curative - will cause regression if not a chronic prolapse.

[ILL. Wykes (2003) Fig 99-7 drawing]

[ILL. Pettit (1998) Fig 31-2 drawing]


Vaginal Neoplasia

Most common location for female (intact or spayed) reproductive tract tumors.  Predisposition for boxer, poodle, and German shepherd.  Most are leiomyoma or transmissible venereal tumor (TVT).


bulging of perineum, vaginal prolapse, tenesmus, dysuria, urinary incontinence, difficulty copulating, sanguinous or purulent discharge


vaginoscopy, digital vaginal exam, rectal palpation in small dogs, cytology.  Abdominal and thoracic radiographs.


Surgical excision - usually easy to remove with episiotomy.


good for completely removed leiomyoma or for TVT     


Leiomyoma - often multiparous bitches.  Tumor is slow growing and associated with tenesmus and dysuria. usually completely encapsulated and can be excised. Sessile or pedunculated. Often reported with chronic estrogen (ovarian tumor or follicular cyst). do not usually metastasize.

Leiomyosarcoma - metastasize to lymph nodes, spleen, lungs, or cervical spinal cord and may recur without metastasis

Transmissible Venereal Tumor (TVT) - transmission, growth, and metastasis depends on immune status of recipient.  May regress or grow slowly in normal animal, may grow quickly and metastasize in immunosuppressed animal.  Treatment for TVT depends on tumor location, presence of metastasis, and availability of treatment modalities.  Sx excision of TVT is associated with high rate of recurrence. Chemotherapy using vincristine has a high cure rate and is useful for metastatic disease.  Orthovoltage radiation therapy works for local tumors.


Vulvar Hypertrophy

may persist with prolonged estrogen due to cystic ovaries, granulosa cell tumor




Vulvar Hypoplasia / Infantile Vulva

(recessed vulva, vulvar inversion)

may be more common in dogs that are spayed at an early age, but not proven. Has also been described in intact females. Obesity may also be a factor.


vulva is hidden into folds of adjacent skin, perivulvar dermatitis. Has also been associated with chronic urinary tract infections, urinary incontinence, and vaginitis.



weight loss is indicated if the animal is obese.

local cleaning of the skin.

episioplasty - crescent shaped bilateral piece of skin removed dorsal and lateral to vulva. remove underlying fat. close subcutaneous tissue and skin.

[ILL. Hedlund (2002) Fig 28-10 drawing of episioplasty]

[ILL. Manfra Marretta (1998) Fig 31-4 thru 31-7drawing of episioplasty]


Mammary Neoplasia



dogs:  most common neoplasia. most commonly in caudal 2 glands.  intact females have 3-7 x increased risk compared to spayed.  spaying has no protective effect after 2.5 yrs or 4 estrus cycles.

[ILL. Hedlund (2002) Fig 28-13 photo]


cats: 3rd most common neoplasia. all glands at equal risk.  intact female has 7x increased risk as compared to spayed.   Siamese cats are predisposed.


Tumor type and Metastasis

dogs:   about 50% benign. (fibroadenoma) most malignant are adenocarcinoma and have mets  to lungs or lymph nodes.

cats: 90% are malignant (adenocarcinoma, also sarcoma and inflammatory carcinoma) and most have mets - lungs and regional nodes.

Influence of Reproductive Hormones on Occurrence

estrogen and progesterone have role in etiology. bind protein receptors in target tissue. patients with receptor rich tumors have greater survival than patients with receptor poor tumors.



history, signalment, physical exam


abdominal and thoracic radiographs and abdominal ultrasound



Treatment Options

Surgical excision

            lumpectomy - remove tumor

            simple mastectomy (mammectomy) - remove affected gland

            en bloc resection - remove affected gland, regional LN, and all glands in between

            unilateral mastectomy - remove all glands on affected side and associated LN

            bilateral mastectomy

[ILL. Hedlund (2002) Fig 28-14 drawing]


Use an elliptical incision, as for any mass removal. Be careful not to get too wide or may have trouble closing. Depth of excision should be to pectoral muscles/abdominal wall fascia. Use good hemostatis and use walking sutures to eliminate dead space and tension. Bilateral mastectomies may need to be staged, removing the second mammary chain 2-4 weeks after the first.

Type of surgery does not affect survival time or cancer free time, so lumpectomy or simple mastectomy of affected glands may be Tx of choice. The most important thing is to get clean margins. 44% of dogs have receptor rich malignant tumors and concurrent OHE of these bitches will increase survival time. (OHE is cheaper than steroid receptor assay.)

cats- unilateral mastectomy have better disease free interval than simple mastectomy but  no difference in survival. OHE is not indicated because cat mammary tumors are receptor poor.

Other therapy:

-Radiation therapy




dogs: depends on tumor size, type, mode of growth and clinical stage. < 5 cm diameter, no invasion or mets - survival same as for benign.  75% of dogs with simple mastectomy  or enbloc did not survive >2 yrs

cats:  average survival 1 year

either species: tumors with lymphatic infiltration, metastasis, body wall invasion, rapid growth, or recurrence have a  poor prognosis


List of textbook references


Gilson SD. Cesarean section In: D. Slatter, ed. Textbook of Small Animal Surgery. 3rd ed. Philadelphia: Saunders, 2003;1517-1520.


Hedlund CS. Surgery of the reproductive and genital systems In: T. W. Fossum, ed. Small Animal Surgery. 2nd ed. St Louis: Mosby, 2002;610-674.


Manfra Marretta S. Episioplasty In: M. J. Bojrab, ed. Current Techniques in Small Animal Surgery. 4 ed. Baltimore: Williams and Wilkins, 1998;506-508.


Manfra Marretta S. Episiotomy In: M. J. Bojrab, ed. Current Techniques in Small Animal Surgery. 4 ed. Baltimore: Williams and Wilkins, 1998;508-510.


Mullen HS. Cesarean section by ovariohysterectomy In: M. J. Bojrab, ed. Current Techniques in Veterinary Surgery. 4 ed. Baltimore: Williams and Wilkins, 1998;500-502.


Pettit GD. Surgical treatment of vaginal and vulvar masses In: M. J. Bojrab, ed. Current Techniques in Small Animal Surgery. 4 ed. Baltimore: Williams and Wilkins, 1998;503-506.


Probst CW. Cesarean section In: M. J. Bojrab, ed. Current Techniques in Small Animal Surgery. 4 ed. Baltimore: Williams and Wilkins, 1998;496-500.


Wykes PM, Olson PN. Vagina, vestibule, and vulva In: D. Slatter, ed. Textbook of Small Animal Surgery. 3rd ed. Philadelphia: Saunders, 2003;1502-1510.

Theriogenology VMED 5361


Fall 2002

Dr. J. Davidson





General Evaluation of Prostatic Disorders. 2

Benign Prostatic Hyperplasia and Cystic Hyperplasia. 3

Suppurative Prostatitis and Prostatic Abscessation. 3

Prostatic Cysts and Paraprostatic Cysts. 4

Prostatic Neoplasia. 5


General Considerations for Prostatic Surgery. 6

Prostatic Biopsy. 6

Prostatic Drainage. 6

Marsupialization. 6

Prostatic Omentalization. 7

Partial Prostatectomy. 7

Complete Prostatectomy. 7


Testicular Hypoplasia. 7

Cryptorchidism.. 7

Orchitis. 8

Testicular Neoplasia. 8

Testicular Trauma. 9

Testicular Torsion. 9


Testicular Biopsy. 10

Orchiectomy. 10

Scrotal Ablation. 11


Hypospadias. 11

Balanoposthitis. 11

Persistent Penile Frenulum.. 12

Phimosis. 12

Paraphimosis. 12

Priapism.. 13

Penile Wounds. 13

Fractured Os Penis. 13

Strangulation. 13

Penile and Preputial Neoplasia. 14

List of references. 14












  1. Be able to diagnose the prostatic diseases based on clinical signs and test results.
  2. Know how to treat prostatic hyperplasia.
  3. Know how to treat prostatic abscesses.
  4. Understand the surgical treatment options for prostatic cysts.
  5. Be able to diagnose prostatic neoplasia and counsel a client about it.
  6. Know the definition of cryptorchidism and the reasons for castration.
  7. Be familiar with the three testicular neoplasias.
  8. Know the indications for and complications of orchiectomy.
  9. Know how to perform prostatic and testicular biopsies.
  10. Know how to perform a scrotal ablation and cryptorchid surgery.
  11. Understand the difference between paraphimosis, priapism, and phimosis.
  12. Recall some penile and preputial neoplasia and recommendations for treatment.

Note: Since most of my illustrations have been borrowed and some have been published, reproducing them would be in violation of copyright laws. References to textbook illustrations have been provided and are marked by “ILL”, for those who are interested. Use of these references is entirely optional and only provided for your convenience. A list of textbook references is provided at the end of these notes.


General Evaluation of Prostatic Disorders

History (Hx)

hematuria, pyuria, stranguria, discharge at end of urination, urine retention, constipation, tenesmus, fever, lethargy, anorexia, dehydration, vomiting, weight loss, pain. 

Physical Exam (PE)

abdominal and rectal palpation. Note prostatic position, pain, contour, texture, mobility, symmetry, and size. Check for enlarged iliac lymph nodes and testicular tumors.

Clinical Pathology

complete blood count (CBC), serum chemistries, Brucella titer, urinalysis (UA). Obtain prostatic fluid by ejaculate, prostatic wash or fine needle aspirate (FNA). FNA (perirectal or transabdominal) is usually the most accurate and diagnostic method.

Radiographs (Rads)

Survey films may show size and position of prostate. It may be abdominal with increased prostatic size, obesity or enlarged bladder. Look for metastasis (mets) in the lumbar vertebrae, regional organs and lungs. Positive contrast cystourethrography may be helpful.

[ILL. Basinger (1993) Fig 99-1 radiograph]

Ultrasound (US)

Note prostatic size, shape, symmetry, echogenicity, and cavitational areas. You may see the iliac lymph nodes if they are enlarged.

[ILL. Basinger (1993) Fig 99-2 thru 99-4 sonograms]

Biopsy (Bx)

Percutaneous bx (transabdominal or perineal) can be done with Tru-Cut or other biopsy needle. US guided is preferred to get a representative sample and avoid the urethra. Needle biopsy is generally avoided if prostatic abscess is suspected.  Wedge bx may be obtained through a caudal abdominal incision.          

Benign Prostatic Hyperplasia and Cystic Hyperplasia

Prostatic hyperplasia is an aging change that is seen histologically in 80% of intact 6 year old dogs and 95% of 9 year olds. It is related to elevated testosterone and estrogen.


most dogs are asymptomatic. constipation, tenesmus, dyschezia, hemorrhagic urethral discharge, incontinence, stranguria, dysuria, urine retention (uncommon).

Diagnosis (Dx)

Rectal palpation reveals symmetrically enlarged, nonpainful prostate of normal spongy consistency.

UA - hemorrhage but no bacteria.

Rads - enlarged prostate may displace bladder cranially and colon dorsally.

US - hyperechoic if benign hyperplasia, small (1-10 mm) cysts if cystic hyperplasia.

Bx- definitive, but may not be necessary if dog responds to treatment.

Treatment (Tx)

Castration is Tx of choice. Prostate will decrease size in 3 wks. Give bulk laxative and low residue diet for constipation. In extreme cases, an indwelling catheter may be needed for urinary retention.

Estrogen will decrease prostatic size but can also cause aplastic anemia and squamous metaplasia of the prostate (which can promote prostatic cysts). Progestin and finasteride may be alternatives to estrogen therapy.


Excellent following castration.

Suppurative Prostatitis and Prostatic Abscessation

The source of prostatic infection is usually via the urethra, although it may be hematogenous. Common infectious organisms include E. coli, Pseudomonas, Staph, Strep, and Proteus.  Normal defense mechanisms include: mechanical flushing, urethral high pressure zone, mucosa, peristalsis, Zn associated antibacterial factor of prostatic fluid.  If the bacteria are not cleared, prostatic infection may progress to microabscessation and then to larger abscesses.



acute prostatitis - lethargy, straining to urinate or defecate, hematuria, abdominal pain.

chronic prostatitis - May have few signs or recurrent urinary tract infections. May have episodes resembling acute prostatitis but milder.

prostatic abscess - Starts out as chronic prostatitis. As abscesses develop, see signs of acute prostatitis but septicemic signs may predominate (fever, anorexia, vomiting, diarrhea, dehydration). If an abscess ruptures, dog may show signs of acute peritonitis with shock (tachycardia, slow CRT, weak pulses, pale mm, severe abdominal pain).



acute prostatitis - Prostate painful and symmetrically enlarged. There may be hindlimb edema from interference of lymph and venous drainage. May have enlarged lymph nodes. CBC: leukocytosis with left shift or leukopenia with degenerative left shift. Prostatic fluid: septic, suppurative. UA: hematuria, pyuria. US: normal or hyperechoic prostate.         

chronic prostatitis - Prostate is nonpainful, firm, symmetrically enlarged. CBC: normal or mild elevation of WBC. Prostatic fluid, UA, and US are similar to acute prostatitis.

prostatic abscess - Small abscess may be palpated as single or multiple soft foci within a firm gland. As the abscesses develop, the prostate becomes painful, large and asymmetrical  (fluctuant areas of pus and firm areas of fibrosis). CBC, prostatic fluid, and UA are similar to acute prostatitis. US: fluid filled areas (>1 cm diameter), decreased echogenicity in surrounding parenchyma, indistinct prostatic borders.



acute prostatitis - Antibiotics for 3 weeks, based on culture and sensitivity. Castration is also recommended if the dog is not systemically ill, since prostatitis may be related to benign hypertrophy.


chronic prostatitis - Same Tx as for acute prostatitis, but antibiotics for 4-8 weeks.


prostatic abscess - If abscesses are small, treat as chronic prostatitis. If dog is systemically ill, supportive care or shock therapy may be needed. Large prostatic abscesses are less likely to respond to medical Tx alone and must also be surgically drained or resected (when the patient is stable). Partial prostatectomy provides more complete resolution of infection with shorter hospitalization as compared to surgical drainage and may also be indicated for recurrent abscesses. Prostatic omentalization may also be tried. The dog should also be castrated. At surgery, get prostatic bx and aerobic and anaerobic cultures.  Also culture the urine for aerobic infection.



short term - sepsis and shock, hypoproteinemia, urinary incontinence, and death. High mortality rate of prostatic abscesses (51%) is usually due to sepsis.

long term - urinary incontinence, recurrent urinary tract infections, recurrent abscessation. hypokalemia, hypoglycemia, anemia, peripheral edema,  PU/PD, diarrhea, wound infection, ventricular arrhythmias, hemorrhage.



acute prostatitis - good if therapy is aggressive and instituted early.

chronic prostatitis - good.

prostatic abscess – good for small abscesses. guarded for abscesses large enough to require abdominal drainage - postoperative mortality is as high as 25%. Mortality is close to 50% for ruptured abscesses.

Prostatic Cysts and Paraprostatic Cysts

Prostatic cysts develop within prostate due to some type of obstruction (squamous metaplasia or functional obstruction by gland oversecretion), although the pathophysiology is uncertain. They may be seen as cavitations within the prostate.


Paraprostatic cysts are of embryonal origin and do not communicate with the prostate. Therefore, they are less likely to be secondarily infected. They are often seen as large structures in the abdominal cavity or pelvic canal.



Dogs are usually bright and alert and may be asymptomatic. Most signs are related to compression of adjacent tissues (tenesmus, stranguria). Other signs include inappetence, constipation, incontinence, urine retention. Palpate asymmetrically enlarged, nonpainful, fluctuant prostate. Usually nonpainful but may have inflammation with adhesions and pain. May palpate abdominal mass. Be sure to check for concurrent Sertoli cell tumor. UA: normal or hematuria. Rads: may be calcified areas in the wall – especially for paraprostatic cysts. FNA: modified transudate with RBCs and epithelial and inflammatory cells. Culture: negative unless secondarily infected/abscessed. US: fluid filled areas, >1 cm diameter.

[ILL. Hedlund (2002) Fig 28-20 photo]



Castration should be performed for small parenchymal cysts. For large cysts or paraprostatic cysts, castrate and also perform one of the following:

drain -  Multiple drains can be placed surgically if the cyst is not respectable. 

marsupialize -Advantages include continuous drainage, can treat interior of cyst, and decreased morbidity. It is often the treatment of choice. Complications include UTI, abscessation, urinary incontinence, and chronic drainage.     

resect cyst - Discrete paraprostatic cysts or true cysts with narrow attachment may be resected with a partial prostatectomy. Incomplete cyst resection is preferable to causing incontinence or detrusor atony (avoid aggressive dissection of the dorsolateral bladder neck, prostate, and pelvic urethra).

omentalization – Packing omentum into the cystic cavity is a recently described technique which shows promise.

partial or complete prostatectomy - This surgery is difficult (i.e. do not try this at home! J) and usually results in incontinence, so it’s rarely indicated. 



Good to fair. Recurrence can be a problem.

Prostatic Neoplasia

Adenocarcinoma and transitional cell carcinoma are the most common types. Castration does not prevent neoplasia. Castrated dogs are more likely to have neoplasia than any other prostatic disease. Prostatic neoplasia commonly mets to iliac lymph nodes, but can also spread to the bladder, rectum, pelvis, lumbar vertebrae, and pelvic musculature.



hindlimb weakness, stranguria, dysuria, tenesmus, dyschezia, PU/PD, cachexia, hematuria, incontinence, hind limb edema.



Palpation of prostate:  often asymmetrically enlarged, usually painful, firm, fixed, and cystic or irregularly nodular. May be able to palpate enlarged lymph nodes. Rads: prostate may have mineral density. Look for enlarged sublumbar lymph nodes and mets to lumbar vertebrae.  US: increased, decreased or mixed pattern of echogenicity. cytology of prostatic fluid may not be diagnostic, but bx is diagnostic. 



Efficacy of chemotherapy or radiation therapy is uncertain. Castration may help temporarily.  Can do complete prostatectomy if no metastasis, but will be incontinent and will not increase survival time. Intraoperative radiation may improve survival time in patients with no metastatic disease.



poor.  Prostatic carcinoma grows fast and mets early so the dog is usually beyond help by the time it’s diagnosed.



General Considerations for Prostatic Surgery

Flush the prepuce with 0.1% povidone iodine or 1:4 dilution of 2% chlorhexidine diacetate before surgical scrub. The surgical approach is a caudal laparotomy lateral to the prepuce and through midline of the abdominal wall. The incision must extend caudally to the pubis.  Retract the bladder cranially with stay sutures. A pubic osteotomy may be needed in some cases. (Cut through the craniomedial third of each pubis to the obturator foramen and then make one cut connecting both foramina to reflect the pubis. To close the pubis is wired back with wire passed through holes drilled in the bones.)

Prostatic Biopsy

A scalpel is used to cut a wedge from the lateral aspect of the prostate, avoiding the urethra. The capsule may be closed with absorbable suture material to help control hemorrhage. An alternative is to use a Tru-Cut biopsy needle.

[ILL. Rawlings (1998) Fig 29-1drawing]

Prostatic Drainage           

Drains may be placed for the treatment of abscesses or cysts. A stab incision is made in the ventrolateral aspect of the abscess or cyst. After cultures and biopsies are obtained, the area is lavaged. Digital manipulation of the prostatic parenchyma is performed to connect all abscessed or cystic areas to create one large cavity if possible.  One or two penrose drains or closed suction drains are placed in each area that requires drainage. Drains are exited through the abdominal wall lateral to the abdominal incision. After surgery the drains are bandaged to prevent ascending infection. Drains are removed as soon as drainage decreases - usually within 1-3 weeks. Complications include dermatitis around the drains, SQ edema, premature drain removal by the patient, and fistula formation.

[ILL. Hedlund (2002) Fig 28-18 drawing]

[ILL. Basinger (1993) Fig 99-8 drawing]


Marsupialization is most commonly used for prostatic cysts. The cyst must be tough enough be sutured and big enough to reach the body wall. Explore the cyst and break down any loculations to make one large cavity. Make a 2-3 cm oval stoma in the skin lateral to the prepuce. Dissect bluntly through the muscle and pull the cyst capsule through the abdominal wall. Suture the cyst to the external rectus and the edges of the cyst to the skin. Irrigate with dilute iodine or saline for several days. Drainage usually decreases after 1 week but may drain for up to 3-4 months.  Complications include premature closure or permanent fistula.

[ILL. Hedlund (2002) Fig 28-22 drawing]

[ILL. Basinger (1993) Fig 99-9 drawing]

Prostatic Omentalization

Omentalization is a newer procedure that has been described for prostatic cysts or abscesses. After obtaining samples for culture and biopsy, the cyst or abscess is explored and transformed into one large pocket as described for placement of prostatic drains and marsupialization. A leaf of the omentum is then tacked into this area.

[ILL. Rawlings (1998) Fig 29-4 thru 29-10drawing]

Partial Prostatectomy

intracapsular technique - removes 80% of parenchyma. Use an electroscalpel or ultrasonic surgical aspirator to remove all the parenchyma except 2-3 mm lining the capsule and the tissue dorsal to the prostatic urethra. The prostatic capsule is closed.

fillet technique – Use a scalpel, electroscalpel or laser to remove all tissue except a rim around urethra using successive passes. Defects in urethral lumen don't need to be sutured. A paraprostatic drain may be placed.

Complications of partial prostatectomy include urine leakage, and incontinence.

[ILL. Hedlund (2002) Fig 28-12 drawing]

[ILL. Basinger (1993) Fig 99-11 drawing]

[ILL. Rawlings (1998) Fig 29-3drawing]

Complete Prostatectomy

Surgical exposure usually requires a caudal abdominal midline approach and a pubic osteotomy. Nerves and vessels to the bladder should be identified and avoided. The vasa deferentia are ligated and divided. The urethra is transected cranial and caudal to the prostate. The urethra is anastomosed with 8-12 sutures. A temporary cystostomy catheter may be placed for 6-7 days if there is tension on the suture line or delayed healing is anticipated. These dogs are usually incontinent and do not respond to medical Tx. Other complications include shock and oliguria.

[ILL. Hedlund (2002) Fig 28-11 drawing]

[ILL. Basinger (1993) Fig 99-10 drawing]

[ILL. Rawlings (1998) Fig 29-2drawing]




Testicular Hypoplasia

Hypoplasia may be unilateral or bilateral and generally these testicles produce androgens but not sperm. Treatment is castration.


Cryptorchidism is a unilateral or bilateral undescended testicle. Anorchism (absence of both testes) and monorchism (absence of one testicle) are rare, so if a testicle is absent it’s probably cryptorchid. The testicle may be intrabdominal or in the inguinal canal. The animal will have normal secondary sex characteristics (cats will have barbs on the penis) due to testosterone, but they will have decreased fertility. Abdominal testicles have a much greater risk of torsion and neoplasia. There is a higher incidence of cryptorchidism among small dogs and Persian cats. It is heredity.


Normal secondary sex characteristics and libido, will be sterile if bilateral.



Testicles have not descended by 6 months of age.



These animals should be castrated to decrease the risk of neoplasia and to prevent them from breeding. If the testicle is palpated in the inguinal region - incise directly over it. If it is not palpable, open the caudal abdomen. The testicle can be found by tracing the ductus deferens from the prostate. The ductus deferens is ligated and divided. The testicular vessels are also ligated and divided. The testicles should be submitted for histological exam. Orchiopexy may be done instead of castration but is not very successful, and not condoned for ethical reasons.



good, even with neoplasia


Infection of the testicle usually originates from the bladder or prostate and gains access to the testicle via the ductus deferens.  Common infectious agents include E coli, proteus, staph, strep and occasionally Brucella. Orchitis may be unilateral or bilateral.



acute -  stiff gait, fever, depression, vomiting, scrotal edema, leukocytosis. palpate firm, hot, painful, swollen testes

chronic - palpate small, firm, irregular testes with enlarged epididymis. Scrotal contents may adhere to tunics. decreased fertility, sterile if bilateral.



culture and aspirate or biopsy of testis  



Medical treatment if not severe - antibiotics, local hypothermia, antiinflammatories.

Castration is treatment of choice for nonbreeding animal.



guarded for fertility

Testicular Neoplasia

Seminoma, interstitial cell, Sertoli cell all have equal frequency and it is common to have more than one tumor of the same or different types in a testicle. Testicular neoplasia is associated with increased incidence of prostatic inflammation and neoplasia, perineal hernia, perianal adenoma and subfertility.


Sertoli cell tumors - largest, most likely to be in ectopic testis and most likely  to secrete estrogens and cause paraneoplastic syndrome: feminization (gynecomastia +/- gland secretion, pendulous prepuce, attract males, loss of libido, alopecia), blood dyscrasia (anemia, thrombocytopenia, and leukocytosis followed by pancytopenia), prostatic squamous metaplasia. this syndrome is not seen in cats. mets to lymph nodes, lungs, liver, spleen, pancreas, and kidney.


Seminoma (not in cats) - usually < 2 cm, but can be bigger. may be locally invasive. more common in cryptorchid testes. rarely have hormone secretion. usually benign


Interstitial cell tumor (not in cats) - 1-2 cm diameter, single or multiple. may be incidental finding. Usually in a scrotal testes and usually benign.



Most are asymptomatic.  Feminization signs occur if the tumor is functional.



Firm, nodular enlargement in scrotum. testicular biopsy



castration. If the tumor is adhered to scrotum, do scrotal ablation as well.  Can do a hemicastration for a breeding animal if the other testicle is clean and has viable sperm. Signs of feminization disappear within 2-6 wks if there're no functional mets.



good if no mets or blood dyscrasias. metastasis is uncommon (<10%)

Testicular Trauma



local pain and swelling, local hypothermia, hindlimb lameness, scrotal hematoma, hemorrhage, spermatic granuloma, infertility



medical - cold compress, supportive bandage, antibiotics, corticosteroids, analgesics, diuretics, aspirate fluid

surgical - If continued hemorrhage, incise scrotum cranially, remove fluid and explore.  Ligate bleeders and suture tears in tunica albuginea. Orchiectomy is indicated for severe trauma.

Testicular Torsion


intraabdominal testicle – (uncommon condition) anorexia, depression, painful abdominal mass, posterior stiffness, dehydration, emesis.

scrotal testicle – (rare condition) anorexia, depression, sudden onset of pain, scrotal swelling, emesis.



orchiectomy with biopsy of testicle.


Testicular Biopsy


evaluate infertility or localized testicular lesion


Open incisional biopsy is least traumatic and most precise. Make the approach as for a castration. Incise the parietal vaginal tunic and place stay sutures in its edges. Take a thin wedge of testicle using a sharp blade. May take sample for culture, cytology and histopathology. Check with your pathologist prior to surgery to see which fixative they prefer – it’s usually Bouin’s or something else other than formalin. Close the tunica albuginea, parietal tunic, subcutaneous tissue, and skin.


hemorrhage, inflammation, increased intratesticular pressure, hyperthermia, infection, adhesions, transient subfertility or permanent infertility.


 (a.k.a. orchidectomy  or castration)


  • sterilization
  • prevent objectionable behavior (aggression, roaming, urine marking, mounting)      
  • testicular or epididymal diseases (testicular hypoplasia, cryptorchidism, severe orchitis, epididymitis, severe testicular trauma, testicular or epididymal neoplasia)
  • scrotal diseases (severe trauma or dermatitis, neoplasia)
  • diseases related to hormone production ( perianal adenoma, perineal hernia,  benign prostatic hyperplasia)


Preoperative evaluation

Physical examination

Diagnostic evaluation is related to animal’s age and reason for surgery


Surgical technique

Refer to Laboratory notes from VMED 5360


Postoperative care

Prevent excessive licking of suture line and watch for swelling or drainage.        

Remove sutures in 7-10 days for dogs.

Use shredded paper instead of litter for 3-5 days for cats.


scrotal hematoma - Scrotum fills with blood due to poor hemostasis.

Tx: benign neglect, surgical drainage or scrotal ablation.

intraabdominal hemorrhage- spermatic vessels retract into abdomen.

Tx: abdominal surgery to ligate vessels. Fluids or blood transfusion PRN.              

scrotal abscess - Tx: surgical drainage or scrotal ablation, and antibiotics

scrotal dermatitis - due to irritation from scrub or clipper burns.

Tx: topical zinc oxide cream or antibiotic steroid cream. scrotal ablation in severe cases.

Scrotal Ablation


scrotal hematoma or abscess, scrotal dermatitis, castration of old dog with pendulous scrotum, adherent testicular tumor, scrotal trauma or neoplasia (mast cell tumor, melanoma), scrotal urethrostomy in dog or perineal urethrostomy in cat.


Make curved incisions on either side of the base of scrotum. Incisions should curve toward the testicle to allow plenty of skin for closure. Close SQ and skin.

[ILL. Boothe (1993) Fig 97-9 drawing]



Hypospadias is a rare congenital condition in which there is incomplete formation of the penile urethra. The urethral opening is identified on the ventral aspect of the penis anywhere from the tip to the perineal region. There is usually underdevelopment of the penis and the prepuce may be incomplete ventrally. The scrotum may be divided.



There may be none if the lesion is distal and the prepuce is okay. Some dogs have urine scald dermatitis. If the penis is underdeveloped urine may pool in the prepuce. Abnormal preputial development may result in chronic exposure of the penis.



Urine scald can be treated by frequent cleaning and topical ointment. Problems with urine pooling can be treated by daily preputial flushing. Exposed penile mucosa should be kept moist with ointment. Preputial reconstruction is needed in some cases to alleviate penile exposure. For major defects penile amputation and urethrostomy is recommended.

[ILL. Hedlund (2002) Fig 28-23 drawing]

[ILL. Boothe (1993) Fig 98-6 photo and 98-7 drawing]

[ILL. Hobson (1998) Fig 33-5 thru 33-7 drawing of hypospadias]

[ILL. Hobson (1998) Fig 33-10 drawing of preputial reconstruction OR Fowler (1998) Fig 33-14]



infection of penis and prepuce


copious yellow or blood tinged discharge. inflamed, thickened mucosa. enlarged lymph nodes near fornix. adhesions between penis and prepuce in severe cases.


eliminate underlying cause (injury, phimosis, foreign body, neoplasia)


guarded. tends to recur

Persistent Penile Frenulum


pain when attempt to extrude penis, ventral deviation of penis, balanoposthitis, urine scald. May be asymptomatic. predisposition in cockers, poodles, and pekes.


cut with sharp scissors



[ILL. Boothe (1993) Fig 98-14 photo]


Inability to protrude penis due to congenital or acquired stricture of the orifice.


congenital - distended prepuce and can't urinate normally (drops or small stream). balanoposthitis and ulceration.

acquired - scarring of prepuce secondary to trauma or neoplasia preventing extrusion. Signs of balanoposthitis.


correct primary cause and surgically enlarge orifice - excise full thickness triangle from the dorsal prepuce (base of the triangle is along the margin of the orifice).  suture parietal mucosa to skin.

[ILL. Hedlund (2002) Fig 28-25 and 28-26 drawing]

[ILL. Hobson (1998) Fig 33-8 drawing]

[ILL. Fowler (1998) Fig 33-12 drawing]


congenital - good. may need second surgery after full grown.

acquired - tumor regrowth, post op fibrosis, paraphimosis


inability to retract penis into prepuce. It may be congenital (narrow preputial orifice and short prepuce) or acquired (mating, trauma, neoplasia, balanoposthitis, foreign bodies, priapism, tangled preputial hairs).


inflammation of glans leads to desiccation, excoriation, necrosis and urethral obstruction. Exposed penis is swollen and painful.

Tx options

- lubricate and hot/cold packs before replacing. check for preputial hairs.

- preputiotomy: temporary or permanent enlargement of orifice may be needed- as for phimosis.

- preputioplasty: If the prepuce is too short it may be lengthened.

- myorrhaphy: shortening of the preputial or retractor penis muscles.

- phallopexy: create adhesion between penis and preputial mucosa.

- amputation if penis is necrotic

[ILL. Hedlund (2002) Fig 28-28 drawing]

[ILL. Boothe (1993) Fig 98-8 photo]


guarded. recurrence is common if animal is not castrated.



persistent erection (without sexual excitement) due to spinal cord injury, constipation, genitourinary infection


distinguish from paraphimosis because penis can be replaced. Can result in paraphimosis if unresolved.


eliminate primary cause

Penile Wounds


intermittent, profuse hemorrhage. (irritation of injury causes penile erection and repeated hemorrhage), may have urine extravasation if ruptured urethra.


pressure hemostasis, lavage, and antibiotics if small wound. ligate large vessels and suture tunica albuginea for cavernous bleeding, sedate to prevent erection.

partial or total penile amputation for very severe or necrotic wounds.

partial amputation: catheterize the urethra and place a tourniquet caudal to the amputation site. incise lateral to the urethra and os penis. dissect the urethra from the os penis and transect both such that the urethra extends beyond the os penis. the urethra is spatulated and sutured to the penile mucosa. (to shorten the prepuce, remove a full thickness rectangle ventrally, slide prepuce back and suture mucosa to skin.)

total amputation: dissect out the entire penis and ligate vessels at the base. transect the penis and make a permanent urethrostomy (scrotal or perineal).

[ILL. Hedlund (2002) Fig 28-24 drawing of amputation]

[ILL. Boothe (1993) Fig 97-9 thru 97-12 drawing of partial amputation]

[ILL. Hobson (1998) Fig 33-1 and 33-2 drawing of partial amputation]

Fractured Os Penis

(rare) it’s usually a transverse fracture with limited soft tissue damage.


signs may include dysuria, hematuria, urethral obstruction, urine extravasation.

Tx options

- nothing - os penis is surrounded by tough fibrous tissue.

- urethral catheter for 5-7 days as a stent if urethral obstruction.

- open reduction with finger plate if catheter can not be passed or os penis is unstable.

- amputation for severe fracture with urethral obstruction that can not be relieved.


results from entangled preputial hairs or rubber band placed maliciously


dysuria, swelling, may be necrosis


remove cause and apply topical antibiotics. Partial penile amputation may be indicated for severe tissue damage.

Penile and Preputial Neoplasia

Neoplasia of the penis and preputial mucosa include transmissible venereal tumor (TVT), squamous cell carcinoma, hemangiosarcoma, fibrosarcoma, and papillomas. Any skin neoplasia can occur on the preputial skin (mast cell tumor, melanoma, hemangiosarcoma, squamous cell carcinoma, hemangioma, papilloma, histiocytoma)


hemorrhage, decreased libido, phimosis or paraphimosis, balanoposthitis, stranguria, palpable mass. May be asymptomatic.

[ILL. Hedlund (2002) Fig 28-31 photo of TVT]


cytology or histopathology


TVT responds well to chemotherapy or radiation (surgery can be considered if the mass is small). Any other penile or preputial neoplasia should be surgically excised. To obtain margins on any malignant neoplasia a partial or total penile amputation with urethrostomy is usually required.

[ILL. Hedlund (2002) Fig 28-24 and 28-29 drawing]



good for TVT and benign tumors. poor for carcinomas, sarcomas



List of references


Basinger. (1993). In “Textbook of Small Animal Surgery” 2nd ed. (Slatter, ed.), Vol. 2, pp. 1349-1367. W. B. Saunders, Philadelphia.


Boothe, H. W. (1993). In “Textbook of Small Animal Surgery” 2nd ed. (D. Slatter, ed.), Vol. 2, pp. 1325-1336. WB Saunders, Philadelphia.


Boothe, H. W. (1993). In “Textbook of Small Animal Surgery” 2nd ed. (D. Slatter, ed.), Vol. 2, pp. 1336-1348. W. B. Saunders, Philadelphia.


Fowler, J. D. (1998). In “Current Techniques in Small Animal Surgery” 4th ed. (M. J. Bojrab, ed.), pp. 534-537. Williams and Wilkins, Baltimore.


Hedlund, C. S. (2002). In “Small Animal Surgery” (T. W. Fossum, ed.), pp. 610-674. Mosby, St Louis.


Hobson, H. P. (1998). In “Current Techniques in Small Animal Surgery” 4th ed. (M. J. Bojrab, ed.), pp. 527-534. Williams and Wilkins, Baltimore.


Rawlings, C. A. (1998). In “Current Techniques in Small Animal Surgery” 4th ed. (M. J. Bojrab, ed.), pp. 479-487. Williams and Wilkins, Baltimore.

Canine Index

contributed by Bruce E Eilts on 19-Aug-98 at 10:39 AM
modified by
Jacqueline R Davidson on 29-Aug-99 at 06:12 PM


contributed by Bruce E Eilts on 25 September 2012


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