PHALLECTOMY IN THE STANDING HORSE

PHALLECTOMY IN THE STANDING HORSE
Carolyn E. Arnold, DVM, DACVS
Texas A&M University, College Station, Texas 77843
Indications for partial phallectomy of the horse include chronic paraphimosis (either
primary or secondary to priapism, debilitation, drug-induced paralysis, traumatic injury, such as
from a breeding accident, or systemic disease), neoplasia that is either too extensive to allow
local treatment or non-responsive to therapy, and stenosis of the distal aspect of the urethra.
Partial phallectomy is generally regarded as a salvage procedure in stallions and is commonly
performed with the horse anesthetized to facilitate surgery. Previously described techniques of
partial phallectomy include Vinsot’s,1 William’s,2 and Scott’s3 techniques, which are used to
amputate various lengths of the free portion of the penis. Regardless of technique used, the
technical challenges of partial phallectomy involve compressing the corporeal tissue at the end of
the stump and creating a new urethral orifice. Complications of partial phallectomy include
hemorrhage from corporeal tissue with potential disruption of the compression sutures, edema
resulting in acute urinary obstruction, and urethral stricture.
Performing partial phallectomy with the horse standing, using regional anesthesia of the
penis, has been reported4 and can be useful for horses that are either a poor risk for general
anesthesia or for horses whose owners have imposed financial restrictions that do not allow for
the expense of general anesthesia. A modification of Vinsot’s technique for phallectomy has
been adapted for use in the standing horse.5 The modifications to Vinsot’s technique of partial
phallectomy include: 1) the creation of a linear urethrostomy as opposed to a triangular shape
urethrostomy 2) altering the location of the urethrostomy to include subischial urethrostomies in
certain cases 3) application of latex tourniquet using a Callicrate Bander (St. Francis, Kansas.),
4) concurrent castration of affected stallions and 5) the use of the procedure in the standing
horse.
To date, we have performed this procedure on 16 horses, with a follow-up period of 1-5
years. Median follow-up time is 3.8 years. Two horses received distal urethrostomies, while 14
horses received subishcial urethrostomies. None of the horses experienced hemorrhage at the site
of amputation, stranguria, or dysuria after surgery. Short term complications affected 2 horses
and consisted of minor hemorrhage from the perineal urethrostomy following urination for 24
hours after surgery. Long term complications included mild urine scalding in 2 horses and the
formation of an adhesion between the distal portion of the amputated penis and the sheath in 1
horse. The author has developed a preference for the subischial urethrostomy, and now performs
most of these procedures on an out-patient basis. One other application of this technique has
been the use of the Callicrate bander as a penile tourniquet during en bloc resection in 2 cases to
shorten surgery time.
References
1. Frank ER. Veterinary Surgery (ed 7). Minneapolis, MN, Burgess, 1964.
2. Williams WL: The diseases of the genital organs of domestic animals (ed 3) Worcester,
MA, Plimpton, 1943.
3. Scott EA. A technique for amputation of the equine penis. J Am Vet Med Assoc 168: 1047,
1976.
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4. Perkins JD, Schumacher J, Waguespack RW, et al. Penile retroversion and partial
phallectomy performed in a standing horse. Vet Rec 153: 184-185, 2003.
5. Arnold CE, Brinsko SP, Love CC, et al: A modification of Vinsot’s technique of partial
phallectomy in the standing horse: 10 cases (2006-2009). J Am Vet Med Assoc 237: 82-86,
2010.
Figure 1.
Side view of the Callicrate bander with the latex loop loaded.
Figure 2.
Top view of the Callicrate bander with the latex loop loaded.
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Figure 3. Placement of the tourniquet and transection of the penis.
Figure 4. Ischemic necrosis seven days after band placement.
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