Perineal hernia is a

hernia A hernia (: hernias or herniae, from Latin, meaning 'rupture') is the abnormal exit of tissue or an organ (anatomy), organ, such as the bowel, through the wall of the cavity in which it normally resides. The term is also used for the normal Devel ...

involving the

perineum The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...

(

pelvic floor The pelvic floor or pelvic diaphragm is an anatomical location in the human body which has an important role in urinary and anal continence, sexual function, and support of the pelvic organs. The pelvic floor includes muscles, both skeletal and ...

). The hernia may contain fluid,

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

, any part of the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

, the

rectum The rectum (: rectums or recta) is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. Before expulsion through the anus or cloaca, the rectum stores the feces temporarily. The adult ...

, or the

bladder The bladder () is a hollow organ in humans and other vertebrates that stores urine from the kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the bladder is a distens ...

. It is known to occur in

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...

s, and other mammals, and often appears as a sudden swelling to one side (sometimes both sides) of the

anus In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the ''exit'' end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facil ...

. A common cause of perineal hernia is surgery involving the perineum. Perineal hernia can be caused also by excessive straining to defecate.

Atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), malnutrition, poor nourishment, poor circulatory system, circulation, loss of hormone, ...

of the

levator ani muscle The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the ...

and disease of the

pudendal nerve The pudendal nerve is the main nerve of the perineum. It is a Mixed nerve, mixed (motor and sensory) nerve and also conveys Sympathetic nervous system, sympathetic Autonomic nervous system, autonomic fibers. It carries sensation from the exter ...

may also contribute to a perineal hernia.

In humans

In humans, a major cause of perineal hernia is perineal surgery without adequate reconstruction. In some cases, particularly surgeries to remove the coccyx and distal sacrum, adequate reconstruction is very difficult to achieve. The posterior perineum is a preferred point of access for surgery in the

pelvic cavity The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproduc ...

, particularly in the

presacral space In human anatomy, the presacral space is inside the pelvis, behind the rectum and in front of the coccyx and sacrum. Normally it is empty, or it contains a pocket of fat. It is usually covered by sigmoid colon. Clinical significance The presacral ...

. Surgeries here include repair of

rectal prolapse A rectal prolapse occurs when walls of the rectum have prolapsed to such a degree that they protrude out of the anus and are visible outside the body. However, most researchers agree that there are 3 to 5 different types of rectal prolapse, depen ...

and anterior

meningocele Spina bifida (SB; ; Latin for 'split spine') is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, ...

, radical perineal prostatectomy, removal of

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

s including

sacrococcygeal teratoma Sacrococcygeal teratoma (SCT) is a type of tumor known as a teratoma that develops at the base of the coccyx (tailbone) and is thought to be primarily derived from remnants of the primitive streak. Sacrococcygeal teratomas are Benign tumor, benign ...

, and

coccygectomy Coccygectomy is a surgical procedure in which the coccyx or tailbone is removed. It is considered a required treatment for sacrococcygeal teratoma and other germ cell tumors arising from the coccyx. Coccygectomy is the treatment of last resort for ...

. Perineal hernia is a common complication of coccygectomy in adults, but not in infants and children (see

). The standard surgical technique for repair of perineal hernia uses a prosthetic mesh, but this technique has a high rate of failure due to insufficient anchoring. Promising techniques to reduce the rate of failure include an

orthopedic Orthopedic surgery or orthopedics ( alternative spelling orthopaedics) is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...

anchoring system, a

gluteus maximus The gluteus maximus is the main extensor muscle of the hip in humans. It is the largest and outermost of the three gluteal muscles and makes up a large part of the shape and appearance of each side of the hips. It is the single largest muscle in ...

muscle flap, an acellular human dermis graft, and an acellular pig collagen graft.

In dogs and cats

In dogs, perineal hernia usually is found on the right side. Most cases are in older intact (not

neutered Neutering, from the Latin ('of neither sex'), is the removal of a non-human animal's reproductive organ, either all of it or a considerably large part. The male-specific term is castration, while spaying is usually reserved for female animals. C ...

) male dogs (93 percent in one study). Breeds that may be at risk include

Welsh Corgi The Welsh Corgi ( or Corgi, plural Corgis, or occasionally the etymologically consistent Corgwn; ) is a small type of herding dog that originated in Wales. The name ''corgi'' is thought to be derived from the Welsh words and (which is muta ...

Boxer Boxer most commonly refers to: *Boxer (boxing), a competitor in the sport of boxing * Boxer (dog), a breed of dog Boxer or boxers may also refer to: Animal kingdom * Boxer crab * Boxer shrimp, a small group of decapod crustaceans * Boxer snipe ee ...

Australian Kelpie The Australian Kelpie, or simply Kelpie, is an Australia, Australian Herding dog, sheepdog capable of Muster (livestock), mustering and droving with little or no guidance. It is a medium-sized dog and comes in a variety of colours. The Kelpie ha ...

Boston Terrier The Boston Terrier is a breed of dog originating in the United States of America. This "American Gentleman" was accepted in 1893 by the American Kennel Club as a non-sporting breed. Boston Terriers are small and compact with a short tail and ere ...

Collie Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds. The type originated in Scotland and Northern England. Collies are medium-sized, fairly lightly-built dogs, with pointed snouts. Many type ...

Dachshund The dachshund ( or ; German: 'badger dog'), also known as the wiener dog or sausage dog, badger dog, doxen and doxie, is a short-legged, long-bodied, hound-type dog breed. The dog may be smooth-haired, wire-haired, or long-haired, with varie ...

s, Old English Sheepdogs, and

Pekingese The Pekingese (also spelled Pekinese) is a dog breed, breed of toy dog, originating in China. The breed was favored by royalty of the Chinese sovereign, Chinese Imperial court as a companion dog, and its name refers to the city of Beijing (Peki ...

. Perineal hernias are rare in female dogs and uncommon in

cat The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...

s. Dogs with

benign prostatic hyperplasia Benign prostatic hyperplasia (BPH), also called prostate enlargement, is a noncancerous increase in size of the prostate gland. Symptoms may include frequent urination, trouble starting to urinate, weak stream, urinary retention, inability t ...

have been found to have increased

relaxin Relaxin is a protein hormone of about 6000 Da, first described in 1926 by Frederick Hisaw. The relaxin family peptide hormones belong to the insulin superfamily and consists of seven peptides of high structural but low sequence similarity; re ...

levels and suspected subsequent weakening of the pelvic diaphragm. In cats, perineal hernias are seen most commonly following perineal

urethrostomy Urethrostomy is a surgical procedure that creates a permanent opening in the urethra, commonly to remove obstructions to urine flow. The procedure is most often performed in male cats, where the opening is made in the perineum. History For many y ...

surgery or secondary to

megacolon Megacolon is an abnormal dilation of the colon (anatomy), colon (also called the large intestine). This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristalsis, peristaltic movements of the bowel. In ...

. Medical treatment consists of treatment of the underlying disease,

enema An enema, also known as a clyster, is the rectal administration of a fluid by injection into the Large intestine, lower bowel via the anus.Cullingworth, ''A Manual of Nursing, Medical and Surgical'':155 The word ''enema'' can also refer to the ...

s, and stool softeners. Because only about 20 percent of cases treated medically are free of symptoms, surgery is often necessary. Recurrence is common with or without surgery. Several surgeries have been described for perineal hernias in dogs. The current standard involves transposition of the

internal obturator muscle The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis. It exits the pelvic cavity through the lesser sciatic foramen. The ...

. This technique has a lower recurrence and complication rate than traditional hernia repair. A new technique uses

porcine The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the genus '' Sus''. Some authorities consid ...

small intestinal

submucosa The submucosa (or tela submucosa) is a thin layer of tissue in various organs of the gastrointestinal, respiratory, and genitourinary tracts. It is the layer of dense irregular connective tissue that supports the mucosa (mucous membrane) an ...

as a

biomaterial A biomaterial is a substance that has been Biological engineering, engineered to interact with biological systems for a medical purpose – either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a Medical diag ...

to help repair the defect. This is can also be done in combination with internal obturator muscle transposition, especially when that muscle is weak.

References

{{Reflist Dog diseases Hernias