Urethral Prolapse in Dogs: Why it happens and how to fix it.

Prolapse of the urethral mucosa is a rare condition that occurs in male dogs.  Young, intact, brachycephalic dogs, such as bulldogs or Boston terriers, are commonly affected.  The cause of the prolapse in most cases is unknown, but may be related to excessive sexual excitement or underlying urogenital disorders such as urethritis or urethral calculi.  Some authors believe that the relationship between brachycephalic breeds and urethral prolapse may be due to abnormal urethral development or increased abdominal pressure secondary to upper airway obstruction that is typical for these breeds.(1)  Increased abdominal pressure could impair venous return and subsequently cause chronic engorgement of the corpus spongiosum tissue surrounding the distal urethra. (1)

Clinical signs

Clinical signs of prolapsed urethra are bleeding from the prepuce, discomfort, and in rare cases, stranguria.  Affected dogs may show excessive licking of the penis.  Examination of the penis by extruding it from the prepuce reveals the protruding mucosa as a characteristic round, donut-shaped mass at the tip of the penis. (Fig. 1a)

Fig. 1a: urethral prolapse in a dog (arrow)

The prolapsed mucosa is bright red to dark purple.  A urethral catheter usually can be passed through the center of the tissue.  Differential diagnosis would include neoplasia such as transmissable venereal tumor, or penile trauma.

Diagnosis

Dogs with urethral prolapse should be thoroughly examined and evaluated for underlying urogenital disease or other disorders. Perform rectal examination to evaluate the pelvic urethra for a mass or calculus. Catheterize the urethra to determine urethral patency and other possible problems such as calculi.  Obtain urine for analysis and culture to rule out bacterial infection of the urinary tract.  Plain film abdominal radiographs and abdominal ultrasonography should be obtained to evaluate the kidneys, urinary bladder, and prostate gland. Positive contrast studies of the urinary tract can be done if indicated.

When urethral prolapse affects in tact male dogs castration should be recommended to decrease sexual excitement, a possible factor in the pathophysiology of urethral prolapse.  Although medical management of urethral prolapse has been described, surgical treatment by either mucosal resection or urethropexy offers the most expeditious option to alleviate clinical signs and prevent recurrence.

Surgical Technique

The animal is anesthetized and placed in dorsal recumbency.  The prepuce and surrrounding area are clipped and aseptically prepared.  The penis and interior of the prepuce are also gently scrubbed and irrigated with antiseptic solution.  After prepping the prepuce for aseptic surgery, the surgical site is draped and the penis extruded using   assistant’s fingers or by placing a Penrose around the caudal aspect of the penis to hold the prepuce caudally. (Fig 1a,b)

Fig. 1b: surgical model of a penis and urethral prolapse

            Urethral mucosal resection

A lubricated, sterile urinary catheter is passed into the urethra.  A 180o incision is made at the base of the prolapsed mucosa, as close to the penile tunic as possible. (Fig 2a,b)

Fig. 2a: incision in urethral mucosa with a scalpel blade

Fig. 2b incising urethral mucosa

The incision can be started with a scalpel (#15 blade), and continued with Metzenbaum or tenotomy scissors. (Fig. 3)

Fig. 3: continuing incision in urethral mucosa with scissors

The mucosa is not initially completely excised all the way around the urethral lumen since this will result in retraction of the mucosa and difficulty in suturing. The incised mucosa is then sutured to the penile tunic with 4-0 or 5-0 Monocryl or PDS in a simple continuous pattern with a small taper needle. (Fig. 4)

Fig. 4: suturing normal mucosa to penile tunic, simple continuous pattern. Note
inside out direction of needle placement (arrow)

Sutures are placed about 2-3 mm apart and the suture bites are made from inside the urethral lumen to the outside.  A recent study found that the simple continuous suture pattern resulted in a decreased incidence of recurrence of urethral prolapse.(2)

Fig. 5: half of the mucosa has been sutured and the pattern ended

Handle the healthy mucosa gently and avoid excessive manipulation with thumb forceps.  After the initial sutures are placed, the remainder of the prolapsed mucosa is resected and then sutured. (Fig. 6) 

Fig. 6: the remainder of the prolapse mucosa is resected and sutured.

Submit the excised tissue for histopathology to definitively rule out neoplasia.

            Urethropexy

An alternative to mucosal resection is urethropexy (3). In this technique, after prepping the site as described above, the prolapsed mucosa is pushed to the inside of the penis using a red rubber catheter. This catheter is modified by removing a portion of the tip lengthwise.  Sutures (4-0 PDS) are placed starting at the outer surface of the penis, then guiding it to the groove in the catheter and then exiting through the mucosa and to the urethral lumen. The suture needle is then redirected to enter the urethral lumen, again within the groove of the catheter, and exits the penis adjacent to the original entry point (mattress pattern). Three or four of these sutures are placed to secure the mucosa to the urethral lumen. 

Postoperative Care

Remove the urinary catheter after the procedure.  Place an Elizabethan collar on the dog to prevent licking of the surgical site.  Intermittent bleeding from the penis may persist postoperatively for a few days.  Tranquilization with acepromazine (0.05 mg/kg subcutaneous or IM, not exceeding a total dose of 3 mg) often is beneficial in reducing bleeding.  Excercise is limited for 7-10 days to leash walking only.  Treatment of underlying urinary problems, such as cystitis or prostatitis, should also be treated appropriately. The absorbable sutures do not need to be removed.

The prognosis for these animals is usually good although recurrence is common; 57% of dogs recurred in one recent study. (2) The treatment of recurrence is to repeat the surgical treatment as described above. Continue to be diligent in looking for an underlying etiology.  Penile amputation combined with scrotal urethrostomy may be necessary in the rare case that does not respond to repeated resection of the prolapsed tissue.

 References

1. Osborne CA, Sanderson SL. Medical management of urethral prolapse in male dogs. In Bonagura and Kirk, eds. Kirk’s Current Veterinary Therapy XII, Philadelphia: WB Saunders, 1995:1027-1029.

       2. Urethral Prolapse in Dogs: A Retrospective Study. Jennifer G. Carr1, DVM, Karen M. Tobias, DVM, MS, Diplomate ACVS, and Laura Smith3, BVMS. Veterinary Surgery 43 (2014) 574–580.

      3. Kirsch JA, Hauptman JG, Walshaw R. A urethropexy technique for surgical treatment of urethral prolapse in the male dog. Journal of the American Animal Hospital Association [2002, 38(4):381-384]

Blog update: Dr. Birchard has published a new book: "Their Tails Kept Wagging", a collection of moving stories about pets with serious illness who survived.  Click here for more information. 

Dog Parks: Outdoor fun, or disaster waiting to happen?

Dangers at the Dog Park: Help your client avoid dangerous conditions and snarling dog fights with these tips

Heather Biele, DVM. Veterinary Economics 55(9): September, 2014, pg. 15

Summary

In this article Dr. Biele offers veterinarians guidelines for advising clients on the “do’s and don’ts” of dog parks. Dog parks, fenced in areas where many dogs can run free together, offer many mental and physical benefits for dogs. But they also can be sites of disease transmission and fighting resulting in serious injury. The following are key points of advice the author suggests to dog owners:

• Be sure the dog is the right temperament for a dog park (not overly fearful or aggressive)
• Keep the dog current on vaccines and flea and tick preventatives
• Perform regular fecal examinations if a frequent visitor to dog parks
• Educate owners to recognize signs of aggression in their dog
• Train the dog to obey simple commands.

A client handout on dog park safety tips is included in the article which can be downloaded from the journal's website.

Commentary

The internet is awash with articles promoting both the benefits and dangers of dog parks. Strong opinions can be found from veterinarians, dog trainers, and owners. The ASPCA has a very detailed and informative piece on the subject on their website. (http://www.aspca.org/pet-care/virtual-pet-behaviorist/dog-behavior/dog-parks)

I am a firm believer in outdoor exercise for dogs. All dogs, especially working breeds that are high energy and high strung, need regular activity and play. Exercise keeps dogs physically and mentally fit and can prevent behavioral issues so common in dogs not given the opportunity to get outside.

However, I also see the down side of uncontrolled multiple dog interaction. 

Dogs are pack animals, but they are also territorial and can become aggressive with little warning. The “big dog:little dog” syndrome that veterinarians see so often is an example of what can go wrong in a dog park. Bite wounds range in severity but are frequently complicated by infection that can become serious and even life threatening.

I am not sure the general public is sufficiently aware of dog behavior to recognize when aggressiveness is imminent in their own dog and others. Even if they were, will they be close enough to their dog at a dog park to intervene and prevent an attack? Education of dog owners about these issues is certainly beneficial, but will it make dog parks safer?

What is your opinion about dog parks? Sometimes I think our profession is not vocal enough about important issues affecting our patients and their owners. We have a unique perspective. Our knowledge and experience are an important resource to local communities about issues relating to animals. Do the benefits of dog parks outweigh the risks? Can anything be done to make dog parks safer (separate areas for large and small dogs, for example)?

Post comments either on the blog or on facebook (Dr. Stephen Birchard, Veterinary Continuing Education). Also, take the poll on dog parks in the upper right corner of the blog site. (view web version to see the poll)

A Video Message to Veterinary Key Points Readers

Buprenorphine in Cats: Is it an effective postoperative analgesic?

Evaluation of the perioperative

analgesic efficacy of buprenorphine,

compared with butorphanol, in cats

Leon N. Warne, DVM; Thierry Beths, DMV, PhD; Merete Holm, DVM;

Jennifer E. Carter, DVM; Sébastien H. Bauquier, DMV

J Am Vet Med Assoc 2014;245:195–202

Summary

In this study the authors compared the analgesic efficacy of buprenorphine vs. butorphanol for cats undergoing ovariohysterectomy.  Cats were divided into 2 groups: one group was premedicated with buprenorphine in combination with medetomidine, and the other group premedicated with butorphanol and medetomidine prior to general anesthesia. A “validated multidimensional composite pain scale” was used to evaluate pain in all cats, and rescue analgesia (methadone and meloxicam) was administered if the score went above a predetermined level (>9 of 28 indicating moderate to severe pain).

The authors hypothesized that buprenorphine would provide superior postoperative analgesia to cats undergoing ovariohysterectomy.

In phase 1 of the study only a premedication dose of the buprenorphine or butorphanol was given. This phase of the study had to be stopped after 10 cats since 9 of them required rescue analgesia immediately postoperatively.

In phase 2 of the study the experimental methods were the same as phase 1 except a second dose of buprenorphine or butorphanol was given during incision closure. In this phase of the study all cats receiving butophanol required rescue analgesia, whereas none of the cats receiving buprenorphine required rescue analgesia.

Commentary

Two key points can be taken from this study:

• Buprenorphine was clearly more efficacious than butorphanol in providing postoperative analgesia.
• After premedicating with buprenorphine, a second dose was required prior to anesthetic recovery (during incision closure) to provide sufficient analgesia.

This is a very practical and well-designed study that has important clinical implications. Buprenorphine appears to be an effective postoperative analgesic for cats and should be considered as a useful element of the veterinary surgeon’s postoperative care in cats. Butorphanol was not an effective analgesic in the study and although possibly useful in other clinical situations, cannot be recommended for cats undergoing ovariohysterectomy or other surgeries with similar pain levels.


What is your experience with buprenorphine in cats as an analgesic?

Cryptorchidism in Dogs: 5 ways to make surgery easier

1. Determine which testicle is retained

Perform a thorough physical examination.(1) Carefully evaluate the scrotum, prescrotal area, inguinal canals, and abdominal cavity. If only 1 testicle is present in the scrotum, push it dorsally and cranially into the inguinal canal to determine whether it is the right or left testicle. After determining which testicle is retained, carefully palpate the prescrotal area and inguinal canal on the affected side. Palpation of the testicle in the inguinal region may be difficult since it can be confused with inguinal fat or lymph node. Ultrasound examination may be helpful to identify the testicle since it has a characteristic appearance (See recent paper on ultrasonography for retained testicles by Felumlee, Reichle, Hecht, et.al. http://onlinelibrary.wiley.com/.../j.1740-8261.../abstract)

Fig. 1: Ultrasound of a cryptorchid dog with a retained testicle found in the abdomen (arrow)

Also perform abdominal palpation, but unless the retained testicle is severely enlarged it will be difficult to palpate.

2. Begin with an incision over the pre-scrotal or inguinal region

Testicles located just cranial to the scrotum can be removed either by pushing the testicle caudally and exposing it through a standard pre-scrotal midline incision, or by simply incising directly over the testicle. Retained testicles in the inguinal area require incision directly over the inguinal canal. (Fig. 2a)

Fig. 2a: Inguinal incision for removal of right sided retained testicle
(Figs 2a through 2f are from: Birchard SJ, Nappier M. Cryptorchidism.
Compend Contin Educ Vet. 2008 Jun;30(6):325-36; quiz 336-7.)

Meticulous and thorough dissection may be required to expose the testicle. Be careful not to injure the pudendoepigastric artery and vein and its branches. It is possible to confuse the inguinal lymph node with the testicle. However, careful dissection and gross examination of the structure should allow differentiation before proceeding with the excision. Once the testicle and associated structures are exposed, remove them as described for prescrotal or normal testicles.

3. For an abdominal testicle, perform a paramedian approach

If one testicle is retained in the abdominal cavity, the paramedian approach to the abdomen offers the advantages of avoiding dissection around the prepuce, which necessitates ligation of the caudal superficial epigastric artery and vein, and not creating dead space in the subcutaneous tissues adjacent to the prepuce. Although the paramedian approach can allow removal of the testicle through a smaller incision than the ventral midline approach, the surgeon should not compromise the exposure of the intra-abdominal structures. Carefully identify the caudal abdominal structures, and expose and remove the testicle only after verifying that the correct structures have been identified. In one clinical study, the prostate gland was inadvertently removed in 3 dogs when insufficient exposure had been obtained while attempting to remove an abdominal testicle.(2) If additional exposure is needed to identify key structures, enlarge the abdominal incision and use appropriate retractors to find the testicle and surrounding organs.

For the paramedian caudal abdominal approach, place the dog in dorsal recumbency, and prepare the ventral abdomen for aseptic surgery. Depending upon the size of dog, make a 6-10 cm incision in the ventral abdomen, approximately 3-4cm lateral to the prepuce. (Fig. 2a)  Incise the subcutaneous tissue to expose the fascia of the rectus abdominus muscle using a scalpel, make a nick incision in the fascia, and sharply incise the fascia with Mayo scissors (not the muscle). (Fig. 2b) 

Fig. 2b: Sharply incise the rectus abdominus fascia with Mayo scissors

Bluntly separate the fibers of the rectus abdominus muscle, beginning with Mayo scissors, then continuing with the index finger of both hands. (Fig. 2c) 

Fig. 2c: Bluntly separate the muscle fibers of the rectus abdominus with fingers

Sharply incise the peritoneum. (Fig. 2d) 

Fig. 2d: Sharply incise the peritoneum with scissors

Place moistened laparotomy sponges on both sides of the body wall, and place a Balfour retractor or hand held retractors to retract the abdominal wall and expose the viscera.

4. Exteriorize the urinary bladder and palpate the prostate gland

If the retained testicle is not immediately seen in the abdominal cavity after making the paramedian approach, exteriorize the urinary bladder and retract it caudally. Identify the prostate gland, and the vas deferens entering the prostate.

Fig. 2e: Exteriorize the urinary bladder and identify the prostate gland and vas deferens

5. Find the vas deferens and follow it to the testicle

Follow the vas deferens cranially until the testicle is located. (Fig. 2e) Triple ligate the vas deferens and the vessels with absorbable suture, cut between the distal 2 ligatures, and remove the testicle.

Rarely, the abdominal approach and identification of the vas deferens may reveal that the testicle is in the inguinal canal. Remove the testicle as previously described in the inguinal approach.

Close the abdominal incision by first closing the external rectus fascia with absorbable suture (e.g. polydioxanone) in either a simple interrupted or simple continuous pattern.(Fig. 2f) Close the subcutaneous tissue and skin routinely.

Fig. 2f: Close the external rectus fascia, subcutaneous tissue, and skin routinely

Fig. 3: Testicular torsion of an abdominal testicle in a 5 month old Boxer
(same dog as in Figure 1) removed by the paramedian approach. 

References

1. Birchard SJ, Nappier M. Cryptorchidism. Compend Contin Educ Vet. 2008 Jun;30(6):325-36; quiz 336-7.
2. Schulz KS, Waldron DR, Smith MM, et al: Inadvertent prostatectomy as a complication of cryptorchidectomy in four dogs. J Am An Hosp Assoc 32: 211-214, 1996.

Blog Update: Dr. Birchard has published a new book: "Their Tails Kept Wagging", a collection of moving stories about pets with serious illness who survived. Click here for more information. 

Surgical Correction of Enlongated Soft Palate in Dogs: Helping brachycephalics breathe.

The soft palate (SP) in the dog forms the partition between the oral and nasopharynx. The cranial border of the SP is attached to the hard palate, and the caudal border extends to the tip of the epiglottis.  Elongated soft palate is one aspect of brachycephalic syndrome and is common in dogs such as English bulldogs, pugs, and Boston terriers. The soft palate is considered elongated if it extends caudally beyond the articulation with the epiglottis. (Fig. 1) 

Fig. 1: Elongated soft palate in a bulldog. (the dog is in ventral recumbency).
Note the tonsils on each side of the palate.

It causes obstruction of the glottis and stertorous breathing which can be a significant respiratory problem in affected dogs. Concomitant stenotic nares worsen the condition by increasing inspiratory effort and causing further extension of the SP into the airway. (see blog on stenotic nares, May 10, 2014)

After obtaining a thorough history and performing a physical examination, take thoracic radiographs to rule out hypoplastic trachea and complications of upper airway obstruction such as pneumonia or pulmonary edema.

Surgical Procedure

A variety of surgical techniques have been described for correction of elongated SP.  The basic objective of surgery is to remove the portion of SP that is causing airway obstruction.  The amount of tissue to be resected is determined by either measuring the portion of SP that extends beyond the tip of the epiglottis, or by removing the portion of SP that extends beyond the caudal pole of the tonsils. (Fig. 2)  

Fig. 2: Incision line for removal of the excess soft palate.
The line connects the caudal pole of the tonsils.

Resection of too much tissue can result in nasal regurgitation of food and water with resultant aspiration pneumonia.

Since hemorrhage is a potential complication of resection, some authors recommend placing a clamp across the area to be removed, removing tissue using electrocautery, or injecting the tissue with epinephrine.  The author does not recommend these techniques since they encourage tissue edema that can be a life-threatening post-operative complication. Surgical laser and the Ligasure device have also been used for soft palate resection.  An atraumatic “cut and sew” technique described many years ago has been very successful in the author's experience and remains my procedure of choice.(1)

Place the animal in ventral recumbency with the head at the end of the table and the mouth held open with an oral speculum. (Fig. 3)  

Fig. 3: Patient positioning for soft palate surgery

Be sure that the endotracheal tube has a competent cuff that is appropriately inflated to prevent aspiration of blood during the procedure. Administer intravenous dexamethasone (0.1 mg/kg) to help control tissue edema secondary to surgical manipulation. Briefly remove the endotracheal tube to examine the soft palate and compare its length to the epiglottis. Replace the tube and secure it in place. Grasp the middle of the SP with an Allis tissue forceps and place stay sutures (4-0 PDS or Monocryl, taper needle) at the lateral aspects of the SP where the incision will be made. (Fig. 4)  

Fig. 4: Stay sutures have been place at the proposed site of incision (dotted line)
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
J Am An Hosp Assoc 19: 288-92

Sharply incise the soft palate with long-handled curved Metzenbaum scissors. (Fig. 5)  

Fig. 5: Angled Metzenbaum scissors (above) are useful for incision of the soft palate.
Conventional scissors are shown below.

Incise half way across the palate; the mucosa of this cut portion is then sutured with the long end of the stay suture in a simple continuous pattern. (Fig. 6) 

Fig. 6: The soft palate has been partially incised and suture closure begun.
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
 J Am An Hosp Assoc 19: 288-92

Then incise across the remaining palate and suture the mucosa in a similar fashion. (Fig. 7)

Fig.7: Completed excision and closure of the soft palate.
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
J Am An Hosp Assoc 19: 288-92

Hemorrhage is usually not a significant problem once the incisions are closed.  The trachea is gently suctioned if hemorrhage was excessive. To check the soft palate for adequate resection of tissue, briefly remove the endotracheal tube to allow comparing the soft palate length to the epiglottis, then replace the tube for the remainder of the dog's recovery from anesthesia.

Postoperative Care

Post-operatively, leave the endotracheal tube in place as long as possible until the animal is fully awake.  The animal should recover in a cool environment and be observed closely for evidence of airway obstruction due to tissue edema.  Keeping the chin elevated seems to help brachycephalic dogs move air during anesthesia recovery. The intravenous steroids can be repeated if edema is suspected. Tramadol is administered for 5 days for analgesia.

Although most dogs recover without incident after soft palate resection, if complications occur they can be life threatening. Therefore recovery from surgery should be in a hospital that has 24 hour care at least for the first night after the procedure. Results of surgery are usually very good; some inspiratory noise may remain but respiratory function should be improved. One study found a good to excellent outcome in 34 dogs with long-term follow up after surgery for brachycephalic syndrome.(2)

References

1. Bright RM, Wheaton LG. A modified surgical technique for elongated soft palate. J Am An Hosp Assoc. 1983; (19): 288-92.

2. Surgical correction of brachycephalic syndrome in dogs: 62 cases (1991-2004).

Riecks TW, Birchard SJ, Stephens JA. J Am Vet Med Assoc. 2007;230(9):1324-8.

For Dog Owners: Ice cubes or ice water do NOT cause GDV (bloat) in dogs

Gastric dilatation volvulus (GDV) is a disorder of dogs characterized by extreme dilation and mal-position of the stomach. It is primarily seen in large breed dogs and is due to a number of predisposing factors. There is no scientific evidence supporting the claim that ingestion of ice cubes or ice water has any relationship to GDV in dogs, and I have never seen a case in which there was a correlation between the two.

On hot days if a large breed dog becomes overheated they will pant heavily in attempt to cool themselves down. This can lead to aerophagia (swallowing air) that can cause excessive gas in the stomach and lead to GDV if other contributing factors are present. Keep your dog cool by avoiding exercise during the hottest part of the day, avoid leaving them in a hot car in the sun in a parking lot, and give them access to plenty of cool, fresh water and a shady place to rest. Also, do not let your dog drink massive amounts of water all at once. After drinking a reasonable amount, take the bowl away and offer more after 15 to 30 minutes. A cool bath can also be helpful if you think your dog has become mildly overheated. Severe hyperthermia is an emergency situation requiring immediate care by a veterinarian.

For more information on GDV in dogs, search this blog for GDV, or contact your local veterinarian.