ileo-anal pouch ileo-anal pouch in medicine, the ileal pouch–anal anastomosis (ipaa), also known as restorative proctocolectomy (rpc), ileal-anal reservoir (iar), an ileo-anal pouch, ileal-anal pullthrough, or sometimes referred to as a j-pouch, s-pouch, w-pouch, or a pelvic pouch, is an anastomosis of a reservoir pouch made from ileum (small intestine) to the anus, bypassing the former site of the colon in cases where the colon and rectum have been removed. the pouch retains and restores functionality of the anus, with stools passed under voluntary control of the person, preventing fecal incontinence and serving as an alternative to a total proctocolectomy with ileostomy. during a total proctocolectomy, a surgeon removes a person's diseased colon, rectum, and anus. for the ileostomy, the end of the small intestine is brought to the surface of the body through an opening in the abdominal wall for waste to be removed. people with ileostomies wear an external bag, also known as an ostomy system or stoma appliance, to collect waste which can be emptied and changed as needed. with an optional ileo-anal pouch procedure, the pouch component is a surgically constructed internal intestinal reservoir; usually situated near where the rectum would normally be. it is formed by folding loops of small intestine (the ileum) back on themselves and stitching or stapling them together. the internal walls are then removed thus forming a reservoir often referred to as a 'pouch'. the reservoir is then stitched or stapled into anal area where the bottom of the rectum was. the first pouch anal-anastomosis surgery in the world was performed by british surgeon sir alan parks in 1976 at the london hospital (called the royal london hospital since 1990). after the first surgery, he continued to develop the procedure at st mark's hospital in london along with his colleague professor john nicholls. pouch surgery is elective, meaning it is entirely optional, and should be done on the basis of choice by people who doctors deem suitable for a pouch after medical evaluations. pouch surgery is considered reconstructive with the benefit being for quality of life and not disease removal, similar in theory to a breast reconstruction after a mastectomy removes diseased breast tissue. before a pouch is created, a person's diseased colon and rectum are removed. after disease removal, standard medical screening exams for pouch candidates include but are not limited to biopsies, radiology imaging, sphincter function tests, fertility consultations for people of childbearing age with the wish to get pregnant, and psychological support due to intensity of the pouch operations. a similar ileal pouch without the anal anastomosis is a kock pouch. a kock pouch is also called a 'continent ileostomy' because while a person has a pouch constructed inside their body, it is located near the abdominal wall and empties via a stoma from the ileum at the person's convenience. a kock pouch does not restore the anal function. the procedure was first premiered by finnish surgeon dr. nils koch in sweden during 1969. it was an evolution in bowel surgery because it created an ileum pouch for storage of waste inside the body eliminating the need for an external bag for waste collection. an ileostomy without a koch pouch functions constantly, meaning, a patient with ileostomy by itself is incontinent because waste is always moving down the bowel and thus the need for an external appliance bag. koch pouch surgery is also elective surgery that only provides a reconstructive benefit after disease removal. it should be the patient's optional choice based on how a person wants to live their life. reasons for ileal-pouch anal anastomosis (ipaa) surgery ileo-anal pouches are constructed for people who have had their colon and rectum surgically removed due to disease, injury, or infection. several diseases and conditions may trigger the need for surgical removal. disease, injury, or infection ulcerative colitis (uc) crohn's disease (in select cases) familial adenomatous polyposis (fap) colon cancer toxic megacolon there is debate about whether patients with crohn's disease and indeterminate colitis are suitable candidates for an ileo-anal pouch due to the risk of the disease occurring in the pouch. crohn's disease can manifest in many different parts of the digestive tract, so the removal of the colon and creation of a pouch, while alleviating symptoms that occurred in the large intestine plus possibly the rectum, does not eliminate crohn's disease. contradictions to pouch surgery additional contradictions that may prevent a person from being able to undergo pouch surgery include but are not limited to weak sphincter muscles, advanced age (elderly) due to the higher risk of fecal incontinence, pelvic radiation therapy, and women with a history of obstetric complications. pouch surgery is not curative but restorative ileum pouch surgery (koch and ipaa) are reconstructive procedures. reconstructive procedures do not cure disease. since they are not curative, reconstructive surgeries are not medically necessary, meaning they are elective operations. several words can be used to describe an 'elective surgery' including optional and patient's choice. pouch reconstruction should never be offered as the only option to a person because it is elective and should be a voluntary choice offered alongside other options that are safe for the person's individual circumstances. while both ulcerative colitis (uc) and familial adenomatous polyposis (fap) patients and are sometimes controversially considered cured of problematic symptoms after pouch creation due to the removal of disease activity in the colon and rectum, there are still many complications that can arise. while life with a pouch is typically viewed by some people plus some medical professionals as a significant improvement compared to life with an ileostomy, patients living with a pouch may still face daily pains and discomforts including the inability to sleep through the night, a changed diet, severe or frequent gas pain, nutrient deficiencies, and the inability to digest certain foods. with regards to ulcerative colitis (uc), the disease is a systemic immune mediated inflammatory disease, also often referred to as an autoimmune condition. the main risk uc presents is typically inflammation that causes ulcers in the lining of the colon and rectum. this common expression happens in the mucosal layer of the intestine that is only present in the colon and rectum (not the small intestine), which is why the disease was named 'ulcerative colitis'. therefore, ulcerative colitis is considered 'cured' of the problematic disease activity in the colon and rectum only, after both the large intestine and rectum are removed. reasons to remove this mucosal layer include severe discomfort that reduces quality of life, bowel perforation from inflammation, and development of tumors that are cancerous from long-term inflammation. even after a person has their colon and rectum removed, the circumstances that created ulcerative colitis still lives on inside that person's body because it is a systemic immune mediated condition. these conditions occasionally manifest in other ways including additional illnesses considered related to ulcerative colitis like primary sclerosing cholangitis (psc) in the liver, the eye condition uveitis, and certain forms of arthritis throughout the body. it is important to understand that pouch surgery does not cure a patient of ulcerative colitis, removal of the diseased mucosal layer in the colon and rectum cures the disease in the colon and rectum only, if the entire colon and full rectum are removed. for example, if a rectal remnant remains, uc disease can be retained in the small remnant. active disease feels similar to ulcerative proctosis when the full natural rectum was in place. it is also medically treated the same way ulcerative proctosis was before any surgery. even if the entire colon and rectum are removed to stop disease activity in this area, the underlying reasons for the expression of the disease in the large bowel and rectum's mucosal layer remain with the person. alternatives to ipaa pouch surgery a pouch should never be offered as the only treatment option due to the fact it is reconstructive and not curative. people who need to have their colon and rectum removed are usually presented with several options including total proctocolectomy with end ileostomy ("barbie" or "ken" butt), colectomy with rectum left in place, pelvic pouch (ileo-anal pouch / ipaa), ileo-rectum anastomosis (ira), or continent ileostomy such as a koch pouch, for example, if someone has weak sphincter muscles or a diseased anus. the end decision should always be the patient's choice, based on if their health permits the option to have a good outcome. pouch surgery comes with a number of well known complications that a person will not be able to imagine as possibilities themselves, therefore, as part of the education and informed consent process before pouch creation surgery is scheduled, risks, complications, and safe alternatives need to be communicated. if a person has indeterminate colitis, they should also be informed before a pouch is recommended and created that their pathology is unknown due to the even higher risk indeterminate folks face. most common complication is pouch inflammation the most common complication of pouch surgery is an umbrella term called pouchitis that encompasses many causes of inflammation of the pouch. the word 'pouchitis' simply means 'pouch inflammation' similar to 'tonsillitis' meaning 'tonsil inflammation' or 'sinusitis' meaning 'sinus inflammation'. while ulcerative colitis pouch patients may experience a dysbiosis sparked type of inflammation more than people who get a pouch because of cancer or fap, pouchitis can be caused by a number of factors in any pouch. pouchitis is grouped into four main categories of origin: inflammatory, mechanical, surgical, or functional. pouchitis, meaning pouch inflammation from various root causes, can be a driver of pouch dysfunction for some. history the surgical procedure for forming an ileal pouch-anal anastomosis (ipaa) was pioneered by sir alan parks at the london hospital, today called the royal london hospital, in 1976. parks' s-pouch premieres as first anal-pouch reconstruction parks' pouch surgery was originally envisioned as a quality of life enhancing procedure for people who needed to have their colon and rectum removed. people who opted to have the procedure would be able to avoid an ileostomy by restoring intestinal continuity with elective, or optional, ileo-anal pouch surgery. shortly after performing the world's first few pouch procedures in 1976, sir alan along with professor john nicholls joined st mark's hospital also in london where they continued to develop the intestinal pouch procedure. the pair first published details of the procedure in the british medical journal in 1978 with the article "proctocolectomy without ileostomy for ulcerative colitis". sir alan parks' ileo pouch-anal anastomosis (ipaa), was a surgical advancement from the ileoanal anastomosis procedure developed in the 1940s. with an ileum-anal anastomosis, the entire colon and rectum were removed. next a surgical join (anastomosis) was used to connect the end of the small intestine (ileum) to the anus. it was described by the german surgeon nissen in 1934 and american surgeons ravitch and sabiston in 1947. the ileum-anal anastomisis was reported to have a high of frequency of liquid movements making it uncomfortable for many people. it was also a surgical advancement from the koch pouch first performed in sweden by finnish surgeon nils koch in 1969 because parks' ileum pouch-anal anastomosis (ipaa), unlike koch's 'continent ileostomy' allowed for restoration of anal evacuation. the original sir alan s-pouches had a bit of intestine at the bottom of the design that often made them difficult to evacuate. some patients later underwent advancement surgery to remove the extra tip of small intestine and lower the pouch directly onto the anus to remedy evacuation difficulties. invention of the j-pouch in 1980, surgeons in japan published the first study on the j-shaped pouch. dr. utunomiya is created with its creation. the j-shaped pouch design eliminated the 'conduit' or bit of intestine at the bottom of sir alan parks' s-pouch formation making it easier for people to empty a j-pouch. as intestinal pouch surgery became more common, the j-pouch eventually became the dominate shape. j-pouches are easier for surgeons to construct than the hand sewn s or w formations because the js are from two loops of ileum plus with the invention of the stapler, js could be stapled, instead of hand-sewn. j-pouches are considered faster and easier to make over ss and ws. invention of the w-pouch the same year as sir alan parks' unexpected death in 1982, his st mark's hospital colleague, professor john nicholls premiered the