REVIEW ARTICLES

A Review of the Surgical Management of Perineal

Hernias in Dogs
Sukhjit Singh Gill, DVM, MS, Robert D. Barstad, DVM, MS

ABSTRACT
Perineal hernia refers to the failure of the muscular pelvic diaphragm to support the rectal wall, resulting in herniation of
pelvic and, occasionally, abdominal viscera into the subcutaneous perineal region. The proposed causes of pelvic dia-
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phragm weakness include tenesmus associated with chronic prostatic disease or constipation, myopathy, rectal abnor-
malities, and gonadal hormonal imbalances. The most common presentation of perineal hernia in dogs is a unilateral or
Journal of the American Animal Hospital Association 2018.54:179-187.

bilateral nonpainful swelling of the perineum. Clinical signs do occur, but not always. Clinical signs may include con-
stipation, obstipation, dyschezia, tenesmus, rectal prolapse, stranguria, or anuria. The definitive diagnosis of perineal
hernia is based on clinical signs and findings of weak pelvic diaphragm musculature during a digital rectal examination.
In dogs, perineal hernias are mostly treated by surgical intervention. Appositional herniorrhaphy is sometimes difficult to
perform as the levator ani and coccygeus muscles are atrophied and unsuitable for use. Internal obturator muscle
transposition is the most commonly used technique. Additional techniques include superficial gluteal and semitendinosus
muscle transposition, in addition to the use of synthetic implants and biomaterials. Pexy techniques may be used to
prevent rectal prolapse and bladder and prostate gland displacement. Postoperative care involves analgesics, antibiotics,
a low-residue diet, and stool softeners. (J Am Anim Hosp Assoc 2018; 54:179–187. DOI 10.5326/JAAHA-MS-6490)

Introduction hernias.10,11 A recent study recommended caudal scrotal castration

Perineal hernia is a common presenting condition in intact male in dogs with perineal hernias, as it eliminates the need for reposi-
dogs.1 Conditions that lead to its development are not fully un- tioning the animal and has a minor postoperative complication rate
derstood, but it is likely a multifactorial disease. It often warrants similar to that of prescrotal castration.12 This article will discuss
surgical intervention. Several surgical techniques have been de- anatomy, etiology, clinical signs, and different surgical techniques
scribed for the treatment of perineal hernias. Appositional her- used for the treatment of perineal hernia in dogs.
niorrhaphy is often not possible due to atrophy of the levator ani
and/or coccygeus muscles. The most commonly used technique is Anatomy of the Pelvic Diaphragm
internal obturator muscle transposition, which is often successful. The pelvic diaphragm is composed of the levator ani and coccygeus
However, additional techniques, including gluteal muscle transpo- muscles (Figure 1). The levator ani muscle extends from the floor of
sition, semitendinosus muscle transposition, synthetic implants, and the pelvis to the ventral aspect of the seventh caudal vertebra. The
biomaterials, may be needed to augment internal obturator muscle coccygeus muscle is a thick muscle lying lateral to the levator ani
transposition.2–7 Complicated perineal hernias, which involve rectal muscle. It originates from the ischiatic spine on the pelvic floor and
prolapse, bladder displacement, or prostate displacement, require inserts ventrally on caudal vertebrae 2 through 5. The sacrotuberous
additional procedures, such as colopexy, cystopexy, and vasopexy.8,9 ligament is a fibrous band running from the transverse process of
Castration is recommended in addition to herniorrhaphy to de- the last sacral and first caudal vertebrae to the lateral angle of the
crease the size of the prostate and reduce the recurrence of perineal ischiatic tuberosity rostral to the pelvic diaphragm. The sciatic nerve

From the Dallas Veterinary Surgical Center, Dallas, Texas. Accepted for publication: December 21, 2016.

Correspondence: sukhjeet_gill@hotmail.com (S.S.G.)

ª 2018 by American Animal Hospital Association JAAHA.ORG 179

 rectangular muscle, which extends between the sacrum and the
first caudal vertebra proximally and the major trochanter distally.
The semitendinosus muscle is a thick muscle, which lies in the
caudal part of the thigh and extends between the ischial tuberosity
and proximal segment of the shank.
The internal pudendal artery and vein and the pudendal nerve
run caudomedially through the pelvic canal on the dorsal surface of
the internal obturator muscle, lateral to the coccygeus and levator ani
muscles. The pudendal nerve lies dorsal to the vessels and divides into
the caudal rectal and perineal nerves. The obturator nerve passes
through the ventral aspect of the levator ani in a caudolateral di-
rection. The external anal sphincter is supplied by the perineal ar-
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teries and innervated by the caudal rectal branch of the pudendal

Journal of the American Animal Hospital Association 2018.54:179-187.

nerve. The superficial gluteal muscle is supplied by the caudal gluteal

artery and innervated by the tibial nerve. The proximal half of the
semitendinosus muscle is supplied by the caudal gluteal artery, and
the distal half is supplied by the caudal femoral artery. This muscle
is innervated by the caudal gluteal nerve.

Etiology
Predisposition
Perineal hernias occur most commonly in mature male intact dogs.1
Although they are rarely encountered in females, two separate case
reports described a perineal hernia with bladder retroflexion in two
young pregnant bitches. Increased intra-abdominal pressure related
FIGURE 1 Anatomy of pelvic diaphragm (oblique view with skin to pregnancy and relaxation of pelvic muscles caused by relaxin were
and subcutaneous tissue removed): a, levator ani muscle; b, coccygeus thought to be the causes in these bitches.13,14 The higher incidence
muscle; c, superficial gluteal muscle; d, internal obturator muscle; e, of perineal hernias in male dogs is not clearly understood. Some
biceps femoris muscle; f, branch of caudal gluteal artery and caudal studies suggested that gender-related anatomic variations in females,
cutaneous femoral nerve; g, semitendinosus muscle; h, external anal such as their larger, broader, and stronger levator ani muscles, to-
sphincter; i, internal pudendal artery and nerve; j, caudal rectal artery gether with broader rectal attachments and larger sacrotuberous
and nerve; k, ventral perineal artery and nerve; l, sacrotuberous liga- ligaments, make them less prone to perineal hernias.15,16 These
ment; m, ischiocavernosus muscle. variations are correlated with the extra load that has to be accom-
modated by the muscles of the pelvic diaphragm during parturi-
lies just cranial and lateral to the sacrotuberous ligament. The sac- tion.15 However, these gender-related variations are not consistent
rotuberous ligament is a landmark for the tendon of internal among different breeds.15,17
obturator muscle and sciatic nerve. The sciatic nerve can be in- Perineal hernias are commonly reported in mixed-breed dogs,
advertently included in a suture or severed by an unaware surgeon. as well as Boston terriers, miniature poodles, Bouviers des Flandres,
The internal obturator muscle is a fan-shaped muscle covering the boxers, Old English sheepdogs, and Pekingese.1,10 Some breeds of
dorsal surface of the ischium. It originates from the dorsal surface long-tailed dogs as well as short-tailed breeds are overrepresented in
of the ischium and pelvic symphysis. Its tendon of insertion passes various studies of perineal hernias.1,10 Whether or not short-tailed
over the lesser ischiatic notch, ventral to the sacrotuberous liga- breeds have a structural weakness of the pelvic diaphragm has not
ment. Other muscles involved in the repair of perineal hernias been determined, although one study found perineal muscles to be
include the external anal sphincter, superficial gluteal muscle, and greater in long-tailed corgis than in short-tailed corgis.17 In a study
semitendinosus muscles. The external anal sphincter is a large, that compared pelvic diaphragm muscles dissected from male short-
circumferential band of skeletal muscle and is the chief guardian of tailed and long-tailed corgis, the authors found a trend for the
the lumen of the anal canal. The superficial gluteal muscle is a flat, weights of the muscles (as a proportion of the total thigh and

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 Surgical Management of Perineal Hernia in Dogs

perineal muscle weight) to be greater in long-tailed corgis.17 How- Role of Rectal Abnormalities
ever, long-tailed breed dogs are also overrepresented in various Rectal abnormalities, such as rectal deviation, sacculation, and di-
1,10
studies of perineal hernias. verticulum, frequently coexist with perineal hernias.23 These con-
ditions are thought to be the consequences of the perineal hernia
Pathogenesis rather than the cause; however, the presence of a rectal diverticulum
Perineal hernia occurs when the pelvic diaphragm muscles weaken, or rectal obstruction may result in excessive straining. A barium
allowing intrapelvic or intra-abdominal structures to move. The study performed in 40 dogs with perineal hernias reported rectal
cause of pelvic diaphragm weakness is poorly understood. Possible deviation in all the dogs.1 According to one study, if these conditions
causes include neurogenic atrophy of muscles of the pelvic dia- are not corrected, they may lead to recurrence.23
phragm, tenesmus associated with chronic constipation or prostatic
disease, rectal abnormalities, hormonal imbalance, and effect of Role of Hormones
relaxin on muscle fiber weakening.1,18,19 The hormonal role in perineal hernia has not been fully elucidated,
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but hormonal imbalances are likely important. No significant dif-

Journal of the American Animal Hospital Association 2018.54:179-187.

Atrophy of Pelvic Diaphragm Muscles ference was found in serum testosterone and estradiol-17 b con-
Atrophy of the pelvic diaphragm is thought to develop as a result of centrations in dogs with or without perineal hernias.24 Another
weakening of the muscles of the pelvic diaphragm, especially the levator study reported a lower number of androgen receptors with low
15,16
ani muscle. An immunohistochemical study revealed destruction sensitivity in the pelvic diaphragm muscles of castrated and intact
of muscle fibers, abnormal-sized muscle fibers, increased expression dogs with perineal hernias as compared with castrated and intact
of epidermal growth factor receptors, caspase-3 activation, and de- normal dogs.25 This study also showed that androgen receptors were
creased expression of transforming growth factor-a in the levator ani significantly upregulated within the levator ani and coccygeus
muscle of dogs with perineal hernias, confirming atrophy of the levator muscles after castration in normal dogs, whereas there was no dif-
ani muscle.20 Caspase-3 is a cysteine protease, which, when activated, ference in these receptors in the castrated and intact dogs with
induces apoptosis in skeletal muscles; therefore, its increased expres- perineal hernias. A retrospective study reported that the risk of re-
sion in affected levator ani musculature suggests increased apoptosis. currence was 2.7 times greater in intact dogs than in castrated
Upregulation of epidermal growth factor receptor suggests a com- dogs.11 Another study reported a reduction of 43% in the recurrence
pensatory effect for decrease in its ligand. Transforming growth factor- of perineal hernias in castrated dogs.10 Relaxin, a polypeptide hor-
a has a potential survival role in skeletal muscles; therefore, its de- mone belonging to the insulin and insulin-like growth factor family,
creased expression suggests muscle fiber degradation. A combined was first reported to cause relaxation of the interpubic ligament of
histological and electromyography study of the external anal sphincter, female guinea pigs.26 Relaxin is thought to affect connective tissue
levator ani muscles, and coccygeus muscles in 40 dogs with perineal components via its effect on collagen metabolism.26,27 In males, the
hernias revealed atrophy of these muscles, with the atrophy thought to primary site of relaxin synthesis is the prostate gland, from which
be of neurogenic origin.21 The nerve damage was localized in the sacral the hormone is secreted in the seminal plasma. It has been suggested
plexus proximal to the muscular branches of the pudendal branches that relaxin may leak from hypertrophied prostate glands, causing
or in the muscular branches. A previous study reported that tenesmus local muscle atrophy and softening of connective tissue, leading to
resulting from prostatic enlargement may apply traction to the nerves perineal hernias.27 An in vivo study done to compare the expression
21
of the sacral plexus. of canine relaxin, relaxin-like factor, and relaxin receptors within the
muscles of the pelvic diaphragm of dogs with perineal hernias and
Role of Prostatic Diseases clinically normal dogs showed higher expression of relaxin receptors
Prostatic disease can participate by enlargement, inflammation, and within the muscles of the dogs with perineal hernias.28 This suggests
pain by causing tenesmus and increasing pressure on the pelvic that relaxin might play a role in the pathogenesis of perineal hernias.
diaphragm. In one study, the prostate gland was within the hernial
contents of 4 of 32 dogs.1 A caudally displaced prostate gland and Clinical Signs and Diagnosis
various anomalies, such as paraprostatic cysts, increases the pressure Most patients with perineal hernias present with a nonpainful
on the pelvic diaphragmatic musculature. A mineralized para- perineal swelling lateral to the anus. They may have other clinical
prostatic cyst was reported to be the source of tenesmus and a signs, which include constipation, obstipation, dyschezia, tenesmus,
contributing factor in the development of a perineal hernia in an rectal prolapse, stranguria, anuria, vomiting, and/or fecal inconti-
intact male dog.22 nence.1,29,30 A study reported that 48% of dogs with perineal hernia

JAAHA.ORG 181
 were presented with perineal swelling and 15% with tenesmus.1 The herniorrhaphy is possible, but it may result in greater postoperative
herniation may be unilateral or bilateral. Occasionally, dogs with discomfort and tenesmus. Therefore, staged procedures are rec-
bladder retroflexion are presented with consequent urinary outflow ommended.8 Recurrences can occur, and due to severe displacement
obstruction and azotemia. of organs, pexy may be necessary. Pexy techniques performed in
The definitive diagnosis of a perineal hernia is based on clinical conjunction with herniorrhaphy include colopexy, vasopexy, and
signs and findings of a weakened pelvic diaphragm during a digital cystopexy. Colopexy may help prevent recurrent rectal prolapse
31
rectal examination. Other diagnostic tests include abdominal ra- after herniorrhaphy. Vasopexy may help prevent displacement of
diography and ultrasonography, which may help in evaluating the the bladder or prostate. Cystopexy helps to maintain the uri-
size of the prostate and determining whether the bladder is dis- nary bladder in its normal location, thereby preventing bladder
placed into the hernia sac. Sometimes, cystourethrography is re- retroflexion.8,9
quired to delineate the position of the bladder. An oral or a rectal
barium study may be beneficial in demonstrating the position of the Appositional Herniorrhaphy
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colon and rectum. Appositional herniorrhaphy was first described in 1944. It utilizes
Journal of the American Animal Hospital Association 2018.54:179-187.

the external anal sphincter and any remnants of the levator ani or
Presurgical Assessment and Preparation coccygeus muscles for primary repair (Figure 2). If the levator
The laboratory evaluation before surgical repair should include a ani muscle is significantly atrophied, then the sacrotuberous
complete blood count, biochemistry, and urinalysis. Any abnor- ligament can be included as a lateral component of the repair.32
malities found during a physical examination or the laboratory With appositional herniorrhaphy, it is sometimes difficult to
evaluation should be thoroughly investigated. Stable patients should close the ventral aspect of the hernia, resulting in a temporary
be fasted the day before the surgery. An enema is not recommended deformity of the anus. This deformity can cause tenesmus and
24 h before the surgery because of potential contamination at the rectal prolapse. If bilateral hernias are present, then procedures
surgical site with liquid feces. Broad-spectrum antibiotics should be could be staged 3–4 wk apart to minimize tension.10 Postoper-
administered to decrease opportunistic pathogens. The commonly ative complications associated with this technique include inci-
used antibiotics include first-generation (cefazolin 22 mg/kg, q 8 h) sional infections, rectal prolapses, fecal incontinence, urinary
and second-generation (cefoxitin 20–30 mg/kg, q 8 h) cephalospo- incontinence, and wound seromas, and they have been reported
rins. Anesthetics are administered according to the status of the to occur in 29–61% of cases. The recurrence rates range from
patient. Epidural anesthetics are useful for supplementing intra- 10–46%.10,30,32
operative and postoperative analgesia. The fecal material should
be manually removed from the dilated rectum after anesthetizing
the patient, and the anal sac should be evacuated. The patient
should be positioned in sternal recumbency, with its tail fixed over
its back, its pelvis elevated, and its hind legs padded. A gauze sponge is
then placed in the rectum, and a purse-string suture is placed around
the anus. A urinary catheter can be placed to facilitate identification
of the urethra at surgery.31

Surgical Treatment
Surgery is the standard of care for perineal hernia in stable animals.
Urinary bladder retroflexion and visceral entrapment require
emergency surgery. Castration is recommended during hernior-
rhaphy to reduce the recurrence of perineal hernias. The most
common surgical technique used for the repair of a perineal hernia is
internal obturator muscle transposition. Several other techniques
have been developed. These include superficial gluteal muscle
transposition, semitendinosus muscle transposition, fascia lata grafts, FIGURE 2 Appositional herniorrhaphy (oblique view). Sutures are
placement of a synthetic mesh, use of canine small intestinal placed between external anal sphincter (a) or remnants of levator ani
submucosa, and use of tunica vaginalis communis.2–7 Bilateral muscle (b), coccygeus muscle (c), and internal obturator muscle (d).

182 JAAHA | 54:4 Jul/Aug 2018

 Surgical Management of Perineal Hernia in Dogs

Internal Obturator Transposition of perineal hernia was reported as long as 1 yr after repair by in-

Herniorrhaphy ternal obturator muscle transposition in 27.4% of cases. Postoper-

This technique utilizes dorsomedial transposition of the internal ative tenesmus is a risk factor for recurrence.39

obturator muscle for the repair of perineal hernias33–35 (Figure 3).

The internal obturator transposition technique reduces tension on Synthetic Mesh Implants
ventral sutures and thus reduces distortion of the external anal Polypropylene mesh has been used alone or as an adjunct to other
sphincter. The utilization of muscle tissue and associated additional procedures for the treatment of perineal hernias.3,4 Reported
blood supply may facilitate the healing process and prevent break- advantages of polypropylene include its strength and ease of han-
36
down of repair site. Internal obturator transposition hernior- dling.40 Synthetic mesh implantation involves suturing the poly-
rhaphy is recommended as the procedure of choice for more propylene mesh to the coccygeus muscle dorsally and medially, to
37
complex or bilateral hernias. With this technique, the internal the sacrotuberous ligament laterally, to the internal obturator
obturator tendon can be transected to provide greater dorsal ele- muscle ventrally, and to the levator ani and external anal sphincter
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16,38
vation of the flap and reduce tension on the suture line. The muscle medially (Figure 4). One study reported that this technique
Journal of the American Animal Hospital Association 2018.54:179-187.

overall complication rates range from 20 to 46%.7,30,34 Postoperative resulted in a success rate of 92%.3 In a slightly modified version of
complications associated with this technique include wound sero- the technique, the ventral aspect of the mesh is secured to the is-
mas, wound infections, rectal prolapses, urinary incontinence, and chium through holes drilled in the ischium.4 The most significant
flatus.38 The recurrence rates range from 0 to 33%. The recurrence complications observed with these techniques are suture sinuses

FIGURE 3 Internal obturator

muscle transposition. (A) (i and ii)
Pelvic diaphragm with hernial defect:
a, remnants of levator ani muscle; b,
external anal sphincter; c, coccygeus
muscle; d, hernial defect; e, internal
obturator muscle; f, internal puden-
dal neuro-vascular bundle. (B) Ele-
vation of the internal obturator
muscle from the ischiatic table. (C)
Dorsomedial transposition of the in-
ternal obturator muscle (arrow).
Placement of sutures between the
external anal sphincter and levator
ani remnants/coccygeus muscle, ex-
ternal anal sphincter and internal
obturator muscle, and the coccygeus
muscle and internal obturator mus-
cle. Asterisk (*) shows ischiatic table.

JAAHA.ORG 183
 results.34 The follow-up time in these studies study was 3 yr. Only
three dogs developed long-term complications, and the success rate
was 89.74%.

Semitendinosus Muscle Transposition

This technique is used for ventral hernias, especially bilateral, or as a
salvage procedure when other techniques have failed (Figure 5). The
semitendinosus muscle is relatively superficial, has a consistent
blood supply, and is large enough to fill a hernia defect. Experi-
mental use of semitendinosus muscle as a ventral perineal flap in
10 mixed-breed dogs without perineal hernias caused no alterations
in clinical gait examinations or in goniometrical and electro-
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neuromyographical studies in pelvic limbs after surgery, but atrophy

Journal of the American Animal Hospital Association 2018.54:179-187.

was detected by ultrasonography and morphological analysis.42 A

modified technique of semitendinosus muscle transposition was
recently described that involves unilateral transposition of the me-
dial half of the longitudinally split semitendinosus muscle.43 This
technique provides sufficient tension to ensure adequate ventral
FIGURE 4 Synthetic mesh implantation. A polypropylene mesh rectal support. When applied in 14 dogs with ventral perineal her-
(d) is secured dorsally and laterally to the coccygeus muscle (b), ven- nias, the technique resulted in the resolution of clinical signs in all
trally to the fascia of the internal obturator muscle (c), and medially to the dogs, with transient low-grade lameness in the limbs of 2 of the
the external anal sphincter (a) and levator ani muscle. dogs. The mean follow-up time in this study was 890 days, and no

(12.5%), which resolve after removing the offending suture.4 The

repair of perineal hernias with the obturator transposition technique
and polypropylene reinforcement in 36 dogs resulted in an overall
success rate of 80.5% with long-term follow-up of 29 mo.41 The
most severe complications reported in this study were incisional
infection (5.6%) and resultant wound dehiscence (12.5%). The re-
currence rate associated with this technique was 12.5%.

Superficial Gluteal Muscle Transposition

Superficial gluteal muscle transposition involves transplanting the
superficial gluteal muscle to reinforce the ischiorectal fossa.2,29,34
When used alone in the repair of perineal hernias, this technique did
not produce desirable results.29,34 The postoperative complication
rates associated with this technique ranged from 15 to 58%, and the
perineal hernia recurred in 36% of the animals.2,29 A modified
version of superficial gluteal muscle transposition allows the defect
to be closed dorsolaterally by transecting the tendon of the muscle
and rotating it 45 degrees caudal to the defect.29 The tendon is FIGURE 5 Semitendinosus muscle transposition. The semite-
sutured to the internal obturator muscle fascia, the caudal border of ndinosus muscle (d) extends between the ischiatic tuberosity and
the muscle is sutured to the external anal sphincter, and the cranial proximal segment of the shank. The transected part of the muscle (b) is
border is sutured to the sacrotuberous ligament. Transposition of rotated medially, passing beneath the anus up to the lateral perineum of
both the internal obturator muscle and the superficial gluteal the opposite side. The medial aspect of the muscle is sutured to the
muscle together in the repair of 52 hernias in 44 dogs resulted in a external anal sphincter (a), and the lateral aspect to the internal ob-
strong pelvic diaphragm, fewer complications, and good long-term turator muscle (c), ischiourethralis muscle (e) and periosteum.

184 JAAHA | 54:4 Jul/Aug 2018

 Surgical Management of Perineal Hernia in Dogs

short-term recurrence was noted. However, long-term recurrence, harvested with minimal morbidity of the donor site and can be
together with tenesmus, was detected in two of the dogs.43 easily implanted. Furthermore, when compared with synthetic
grafts, the autogenous nature of the graft minimizes the risk of
Biomaterials foreign body reactions and does not form a nidus for persistent
In recent years, significant advances have been made in the use of infection. Fascia lata grafts used for the repair of perineal hernias in
different biomaterials in the repair of perineal hernias. Biomaterials 15 dogs resulted in no recurrence within 5–20 mo.7 Lameness in the
evaluated for the treatment of perineal hernias in dogs include canine donor limb was the most frequent but transient complication as-
small intestinal submucosa, autologous tunica vaginalis communis, sociated with this technique.7
and fascia lata.
Pexy Techniques
Canine Small Intestinal Submucosa Cystopexy, colopexy, and vasopexy, in conjunction with castration,
Submucosa derived from canine intestine has been used in the repair have been used as adjunctive therapies for the treatment of perineal
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of perineal hernia. As it is an allograft, it is associated with fewer hernias.9 Cystopexy, colopexy, vasopexy, and prostatic omentaliza-
Journal of the American Animal Hospital Association 2018.54:179-187.

complications as compared with xenografts and synthetic materials. tion, followed by herniorrhaphy with the internal obturator muscle
It is also resistant to infection. Canine small intestinal submucosa flap or appositional technique, in 41 dogs resulted in the resolution
consists primarily of an extracellular matrix, but it also contains of hernias in 37 dogs.8 Cystopexy and colopexy have been used to
factors involved in angiogenesis, cell migration, and cell differenti- prevent the recurrence of bladder retroflexion and rectal prolapse or
ation. The use of canine small intestinal submucosa allografts derived as a preliminary procedure prior to definitive hernia repair.13,51
from a cadaver in the treatment of perineal hernias in two dogs Vasopexy performed to correct retrodisplacement of the prostate
resulted in improvement in defecatory tenesmus, no signs of re- gland and urinary bladder, in conjunction with herniorrhaphy, in
jection or self-immune responses, and no complications for 12 mo nine dogs led to excellent outcomes.52 The complications involved
5
after surgery. with these techniques include tenesmus, colitis, constipation, and
urinary incontinence.8,9 A recent study showed that urinary bladder
Autologous Tunica Vaginalis Communis retroflexion was not associated with an increased rate of postoper-
Tunica vaginalis communis is derived from the peritoneum, which is ative complications.53 This study also reported that laparotomy
composed of mesothelium and connective tissue. It has been ex- performed to correct bladder retroflexion and rectal prolapse in 21
perimentally used as an autologous, homologous, or heterologous dogs prior to internal obturator muscle transposition offered no
graft for reconstruction of urethral defects in rabbits, abdominal wall clear advantage. Therefore, it was concluded that internal obturator
defects in rats, umbilical hernias in sheep, and urinary bladder wall muscle transposition alone was adequate for the repair of perineal
defects in dogs.44–46 The application of autologous tunica vaginalis hernias.
communis as a free graft in the repair of 11 perineal hernias resulted
in no recurrence or discomfort during defecation and urination in Postoperative Care
7
10 hernias followed up for a median time of 13 mo. The tunica In the immediate postoperative period, analgesic opioids and anti-
vaginalis communis was harvested during a closed prescrotal cas- inflammatory drugs are given to minimize postoperative dis-
tration before the hernia repair. A histopathological examination of comfort. Commonly used opioids include hydromorphone and
the apposing area between the graft and adjacent tissue revealed methadone. Commonly used anti-inflammatories include melox-
neovascularization and connective tissue ingrowth.6 icam and carprofen (cyclo-oxygenase-2 inhibitory nonsteroidal
anti-inflammatory drugs). Oral analgesics, opioids, and nonsteroidal
Fascia Lata anti-inflammatories are continued at home for 5–7 days. Patients are
Fascia lata grafts have been widely used in humans for the treatment also placed on a low-residue diet and stool softeners (lactulose) for
of various disorders, such as male urinary incontinence, tendon 8–12 wk. Fluid therapy should be continued in uremic patients.
47–49
rupture repair, and reconstruction of abdominal wall defects. Intravenous antibiotics are continued in the postoperative period for
Fascia lata grafts have been utilized in articular cranial cruciate 24 h. As the use of antibiotics has been shown to decrease the rate of
ligament repair in dogs and in hip joint capsular tear repair after postoperative incisional infections, patients are often sent home
traumatic dislocation.50 They can be used for primary hernior- with oral antibiotics for 7–10 days.30 The commonly used antibiotics
rhaphy, to augment another procedure, or for the treatment of re- for at-home administration include first-generation cephalosporins
currence after other procedures.7 Fascia lata grafts can be easily and amoxicillin/clavulanic acid. Cold compresses are applied to the

JAAHA.ORG 185
 surgery site immediately after surgery to minimize hemorrhage and 22. Head LL, Francis DA. Mineralized paraprostatic cyst as a potential
inflammation. An Elizabethan collar is placed to prevent the patient contributing factor in the development of perineal hernias in a dog. J Am
Vet Med Assoc 2002;221:533–5.
from licking or chewing the incision site until suture removal.
23. Krahwinkel DJ. Rectal diseases and their role in perineal hernia. Vet Surg
1983;12:160–5.
REFERENCES 24. Mann FA, Boothe HW, Amoss MS, et al. Serum testosterone and es-
tradiol 17-beta concentration in 15 dogs with perineal hernia. J Am Vet
1. Hosgood G, Hedlund CS, Pechman RD, et al. Perineal herniorrhaphy: per-
Med Assoc 1989;194(11):1578–80.
ioperative data from 100 dogs. J Am Anim Hosp Assoc 1995;31(4):331–42.
25. Mann FA, Nonneman DJ, Pope ER, et al. Androgen receptors in the
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