Diversion of the urine stream by surgical modification of the preputial ostium in a dog

Michael M. Pavletic Department of Surgery, Angell Animal Medical Center, 350 S Huntington Ave, Boston, MA 02130.

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Douglas E. Brum Department of Medicine, Angell Animal Medical Center, 350 S Huntington Ave, Boston, MA 02130.

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Abstract

Case Description—A 1.4-year-old sexually intact male Standard Poodle was evaluated with a history of urinating on its left forelimb and lower portion of the thorax.

Clinical Findings—Physical examination revealed that the dog had an unusually elevated (tucked) abdominal wall and prominent dome-shaped thoracic wall. These anatomic changes altered the angle of the urine stream, resulting in the dog's soiling the xiphoid region of the thorax and left forelimb.

Treatment and Outcome—The dorsal half of the preputial ostium was closed surgically to divert the urine stream in a ventral direction. The ventral portion of the ostium was reciprocally enlarged. Postoperatively, the dog urinated in a downward direction, eliminating urine contact with the body.

Clinical Relevance—The preputial orifice (ostium) plays an important role in the shape and direction of the urine stream exiting the penile urethra. Dogs with an elevated abdominal wall and prominent dome-shaped thorax may be prone to contamination of the lower portion of the thorax and forelimbs with urine during normal micturition. Partial closure of the dorsal preputial ostium, with reciprocal enlargement of the lower half of the orifice, can create a deflective barrier that effectively diverts the urine stream in a ventral direction.

Abstract

Case Description—A 1.4-year-old sexually intact male Standard Poodle was evaluated with a history of urinating on its left forelimb and lower portion of the thorax.

Clinical Findings—Physical examination revealed that the dog had an unusually elevated (tucked) abdominal wall and prominent dome-shaped thoracic wall. These anatomic changes altered the angle of the urine stream, resulting in the dog's soiling the xiphoid region of the thorax and left forelimb.

Treatment and Outcome—The dorsal half of the preputial ostium was closed surgically to divert the urine stream in a ventral direction. The ventral portion of the ostium was reciprocally enlarged. Postoperatively, the dog urinated in a downward direction, eliminating urine contact with the body.

Clinical Relevance—The preputial orifice (ostium) plays an important role in the shape and direction of the urine stream exiting the penile urethra. Dogs with an elevated abdominal wall and prominent dome-shaped thorax may be prone to contamination of the lower portion of the thorax and forelimbs with urine during normal micturition. Partial closure of the dorsal preputial ostium, with reciprocal enlargement of the lower half of the orifice, can create a deflective barrier that effectively diverts the urine stream in a ventral direction.

A 1.4-year-old sexually intact male Standard Poodle weighing 24 kg (53 lb) was referred to Angell Animal Medical Center with a history of urinating on its left forelimb and lower portion of the thorax. This problem became evident to the owner when the dog was < 6 months of age. The dog also had a history of intermittent pneumonia that responded to antimicrobial treatment that was based on microbiological culture results and cytologic evaluation of tracheal samples.

On physical examination (day 1), there were no observable abnormalities; the prepuce and penis were normal in shape and proportion. However, the dog had a distinctly elevated or tucked abdomen and a prominent dome-shaped thorax on lateral profile. The dog also had a 4-legged stance while urinating. As a result, both the angle and elevated position of the prepuce and penis caused the downward trajectory of the urine stream to partially strike the xiphoid area tangentially before continuing forward to the caudal aspect of the lower portion of the left forelimb and foot. Although the owners conscientiously washed the soiled areas after every micturition, the dog retained a distinct urine odor. Results of a CBC and serum biochemical analyses were within reference limits.

To alleviate the problem of soiling its body during micturition, the dog was scheduled for surgical modification of the preputial ostium to redirect the urine stream. Prior to induction of anesthesia (day 2), the dog received morphine (0.1 mg/kg [0.05 mg/lb], IM) and medetomidine hydrochloride (0.04 mg/kg [0.02 mg/lb], IM). Anesthesia was induced with thiopental (11 mg/kg [5 mg/lb], IV). The dog was intubated, and anesthesia was maintained with isoflurane and oxygen. Lactated Ringer's solution was administered IV at a rate of 5 mL/kg/h (2.3 mL/lb/h) until completion of the surgical procedure. The dog was placed in dorsal recumbency. The hair over the caudal aspect of the abdomen, prepuce, and scrotal area was clipped, and the sites were prepared for surgery with chlorhexidine surgical scrub solutiona alternated with sterile saline (0.9% NaCl) solution.

After draping of the surgical area, a prescrotal approach was used to castrate the dog. To divert the urine stream in a ventral direction, the mucocutaneous junction was resected along the upper half of the preputial orifice (Figure 1). Interrupted, 4-0 polydioxanone suturesb were used to align the opposing mucosal borders, followed by a series of simple interrupted skin sutures.

Figure 1—
Figure 1—

Photographs of the surgical modification made to the preputial ostium in a 1.4-year-old sexually intact male Standard Poodle that had a history of urinating on its left forelimb and lower portion of the thorax. A—Excision of the mucocutaneous junction of the upper half of the preputial ostium (arrows). A skin hook was used to elevate the mucosal margin, facilitating this procedure. B—Partial closure of the ostium. The opposing sides of the mucosa and skin were closed independently with 4-0 absorbable sutures. To regain the normal diameter of the orifice, a ventral midline incision (arrow) was required that approximated the dorsal area closed. C—After completion of the procedure, partial extrusion of the penis highlights the newly created preputial ostium.

Citation: Journal of the American Veterinary Medical Association 235, 9; 10.2460/javma.235.9.1067

Following closure of the upper preputial ostium, the ventral border of the preputial orifice was incised, creating a V-shaped incision that approximated the length of the closed dorsal ostium (Figure 1). The adjacent cutaneous and mucosal borders were sutured, restoring the overall size of the preputial ostium. The dog was then allowed to recover from anesthesia. Post-operatively, the dog received butorphanol (0.9 mg/kg [0.4 mg/lb], SC, q 8 h) during hospitalization.

After complete anesthetic recovery, the dog was taken outdoors for a walk. The dog urinated with the stream now diverted directly downward. The dog subsequently urinated in an identical fashion before being discharged from the hospital the following morning (day 3). The owners were instructed to give the dog butorphanol (0.86 mg/kg [0.39 mg/lb], PO, q 8 h) for 3 days. Skin sutures were removed 10 days after surgery. At 6 months, the owners reported that the urine stream continued to exit the prepuce in a straight line, perpendicular to the long axis of the dog, without striking any portion of the dog's body.

Discussion

The prepuce is described as a protective sheath enveloping the nonerect glans of the penis (paras longa glandis and a portion of the bulbis glandis).1,2 The prepuce comprises an external (cutaneous) lamina and internal (mucosal) lamina that are continuous at the ostium preputiale.1

The preputial ostium also plays an important role in controlling the shape and direction of the urine stream exiting the penile urethra. The angle of the urine stream during micturition can be influenced by the natural length of the dorsal preputial skin fold reflecting off the caudal aspect of the abdomen. This dog urinated from a 4-legged stance, whereas most male dogs elevate a hind limb during micturition. This stance, along with the exaggerated elevation of the abdominal wall, altered the cranial trajectory of the urine stream, resulting in the dog's urinating primarily on its left forelimb. The prominent dome-shaped arc of the lower thoracic wall also caused urine to strike the xiphoid area tangentially.

In general, caution is required when resecting areas of skin adjacent to the preputial ostium; skin tension can alter the location of the orifice, resulting in angular displacement of the urine stream. In the dog of our report, closure of the dorsal half of the preputial ostium created a deflective barrier, diverting the urine stream in a straight ventral direction. Reciprocal enlargement of the ventral portion of the ostium was performed to assure the penis could be extruded, thereby avoiding the risk of phimosis and the possibility of paraphimosis. Veterinarians should keep in mind the role the preputial ostium plays in directing the urine stream exiting the penile urethra.

a.

Chlorhexidene gluconate, Dial Corp, Scottsdale, Ariz.

b.

PDS II, Ethicon Inc, Somerville, NJ.

References

  • 1.

    Evans HE. Miller's anatomy of the dog. 3rd ed. Philadelphia: Elsevier-Saunders, 1993;530533.

  • 2.

    Boothe HW. Penis, prepuce, and scrotum. In: Slatter D, ed. Textbook of small animal surgery. 3rd ed. Philadelphia: WB Saunders Co, 2002;15351540.

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  • Figure 1—

    Photographs of the surgical modification made to the preputial ostium in a 1.4-year-old sexually intact male Standard Poodle that had a history of urinating on its left forelimb and lower portion of the thorax. A—Excision of the mucocutaneous junction of the upper half of the preputial ostium (arrows). A skin hook was used to elevate the mucosal margin, facilitating this procedure. B—Partial closure of the ostium. The opposing sides of the mucosa and skin were closed independently with 4-0 absorbable sutures. To regain the normal diameter of the orifice, a ventral midline incision (arrow) was required that approximated the dorsal area closed. C—After completion of the procedure, partial extrusion of the penis highlights the newly created preputial ostium.

  • 1.

    Evans HE. Miller's anatomy of the dog. 3rd ed. Philadelphia: Elsevier-Saunders, 1993;530533.

  • 2.

    Boothe HW. Penis, prepuce, and scrotum. In: Slatter D, ed. Textbook of small animal surgery. 3rd ed. Philadelphia: WB Saunders Co, 2002;15351540.

    • Search Google Scholar
    • Export Citation

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