Perineal hernia is a hernia

Hernia

A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm....

 involving the perineum

Perineum

In human anatomy, the perineum is a region of the body including the perineal body and surrounding structures...

 (pelvic floor

Pelvic floor

The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the...

). The hernia may contain fluid, fat

Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

, any part of the intestine

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

, the rectum

Rectum

The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...

, or the bladder

Urinary bladder

The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

. It is known to occur in human

Human

Humans are the only living species in the Homo genus...

s, dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

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

Anus

The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...

.

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

Tenesmus

Rectal tenesmus is a feeling of incomplete defecation. It is experienced as an inability or difficulty to empty the bowel at defecation...

). Other causes include prostate

Prostate

The prostate is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals....

 or urinary disease, constipation

Constipation

Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...

, anal sac

Anal glands

The anal glands or anal sacs are small glands found near the anus in many mammals, including dogs and cats. They are not found in humans or other primates. They are paired sacs located on either side of the anus between the external and internal sphincter muscles. Sebaceous glands within the...

 disease (in dogs), and diarrhea

Diarrhea

Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

. Atrophy

Atrophy

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...

 of the levator ani muscle and disease of the pudendal nerve

Pudendal nerve

The pudendal nerve is a sensory and somatic nerve in the pelvic region which is a large branch of the sacral plexus that innervates the external genitalia of both sexes, as well as sphincters for the bladder and the rectum...

 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

Pelvic cavity

-External links:* * *...

, particularly in the presacral space

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:...

. Surgeries here include repair of rectal prolapse

Rectal prolapse

Rectal prolapse normally describes a medical condition wherein the walls of the rectum protrude through the anus and hence become visible outside the body.-Types:There are three chief conditions which come under the title rectal prolapse:...

 and anterior meningocele, radical perineal prostatectomy

Radical perineal prostatectomy

Radical perineal prostatectomy is a surgical procedure wherein the prostate gland is removed through an incision in the area between the anus and the scrotum . It is typically performed to remove early prostate cancer...

, removal of tumor

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

s including sacrococcygeal teratoma

Sacrococcygeal teratoma

Sacrococcygeal teratoma is a teratoma located at the base of the coccyx . It is thought to be a derivative of the primitive streak.-Natural history:...

, and coccygectomy

Coccygectomy

Coccygectomy is a surgical procedure during which the coccyx, is removed. It can be performed for many reasons for instance in patients with coccyx pain , however it is typically reserved for patients with malignant cancer or for patients whose tailbone pain has failed to respond to nonsurgical...

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

Coccygectomy

Coccygectomy is a surgical procedure during which the coccyx, is removed. It can be performed for many reasons for instance in patients with coccyx pain , however it is typically reserved for patients with malignant cancer or for patients whose tailbone pain has failed to respond to nonsurgical...

).

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 new techniques to reduce the rate of failure include an orthopedic anchoring system, a gluteus maximus 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

Neutering, from the Latin neuter , is the removal of an animal's reproductive organ, either all of it or a considerably large part. The process is often used in reference to males whereas spaying is often reserved for females. Colloquially, both terms are often referred to as fixing...

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

Welsh Corgi

The Welsh corgi is a small type of herding dog that originated in Wales. Two distinct breeds are recognized: the Pembroke Welsh corgi and the Cardigan Welsh corgi, with the Pembroke being the more common..-Description:...

s, Boxer

Boxer (dog)

Developed in Germany, the Boxer is a breed of stocky, medium-sized, short-haired dog. The coat is smooth and fawn or brindled, with or without white markings. Boxers are brachycephalic , and have a square muzzle, mandibular prognathism , very strong jaws and a powerful bite ideal for hanging on to...

s, Australian Kelpie

Australian Kelpie

The Kelpie is an Australian sheep dog successful at mustering and droving with little or no command guidance. They are medium-sized dogs and come in a variety of colours...

s, Boston Terrier

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. Color and markings are important when distinguishing this breed to the AKC standard. They should be either black,...

s, Collie

Collie

The collie is a distinctive type of herding dog, including many related landraces and formal breeds. It originates in Scotland and Northern England. It is a medium-sized, fairly lightly built dog with a pointed snout, and many types have a distinctive white pattern over the shoulders. Collies...

s, Dachshund

Dachshund

The dachshund is a short-legged, long-bodied dog breed belonging to the hound family. The standard size dachshund was bred to scent, chase, and flush out badgers and other burrow-dwelling animals, while the miniature dachshund was developed to hunt smaller prey such as rabbits...

s, Old English Sheepdog

Old English Sheepdog

The Old English Sheepdog is a large breed of dog which was developed in England from early herding types of dog. The Old English Sheepdog has very long fur covering the face and eyes...

s, and Pekingese

Pekingese

The Pekingese, or "Peke" is an ancient breed of toy dog, originating in China. The breed was favored by the Chinese Imperial court, and its name refers to the city of Beijing where the Forbidden City resides...

. Perineal hernias are rare in female dogs and uncommon in cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

s.

Dogs with benign prostatic hyperplasia

Benign prostatic hyperplasia

Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....

 have been found to have increased relaxin

Relaxin

Relaxin is a protein hormone first described in 1926 by Frederick Hisaw.The relaxin-like peptide family belongs in the insulin superfamily and consists of 7 peptides of high structural but low sequence similarity; relaxin-1 , 2 and 3 , and the insulin-like peptides, INSL3, INSL4, INSL5 and INSL6...

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

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:...

 surgery or secondary to megacolon

Megacolon

Megacolon is an abnormal dilation of the colon . The dilatation is often accompanied by a paralysis of the peristaltic movements of the bowel...

. Medical treatment consists of treatment of the underlying disease, enema

Enema

An enema is the procedure of introducing liquids into the rectum and colon via the anus. The increasing volume of the liquid causes rapid expansion of the lower intestinal tract, often resulting in very uncomfortable bloating, cramping, powerful peristalsis, a feeling of extreme urgency and...

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

Obturator internus muscle

The 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....

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

Pig

A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

 small intestinal

Small intestine

The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...

 submucosa

Submucosa

In the gastrointestinal tract, the submucosa is the layer of dense irregular connective tissue or loose connective tissue that supports the mucosa, as well as joins the mucosa to the bulk of underlying smooth muscle .-Contents:Blood vessels, lymphatic vessels, and nerves will run through...

 as a biomaterial

Biomaterial

A biomaterial is any matter, surface, or construct that interacts with biological systems. The development of biomaterials, as a science, is about fifty years old. The study of biomaterials is called biomaterials science. It has experienced steady and strong growth over its history, with many...

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