This revolutionary operation challenged the conventional procedure used at the time, total procotocolectomy, which included removal of the anal sphincter leaving the patient with an ileostomy for life.
The decision to undergo the pouch operation was made by the patient based on objective information and their preference between life with a permanent ileostomy or the preservation of defaecation through the anus, in each case with the removal of the disease.
[12][13] Nicholls was his first assistant having spent 1976 carrying out research under Fritz Linder[14] on an Alexander von Humboldt Fellowship in the Department of Surgery at the Heidelberg University in Germany.
Next, using the last 45 centimetres of the ileum, the construction of an ileal pouch with a valve designed only to allow drainage of its contents when a catheter was passed through the stoma on the abdominal wall.
Parks then constructed a reservoir or "pouch" made from the last 40–50 centimetres of the small bowel (ileum) after excision of the colon and rectum and joined this to the anus to form an ileo-anal anastomosis.
It is also now performed for a number of conditions beyond ulcerative colitis and familial adenomatous polyposis (FAP) including accident or injury, infection, allergic reaction, toxic mega colon, and cancer among others.
[17] Parks' original design, the so-called "S-pouch", was often followed by difficulty in evacuation of stool due to the retention of a short segment of ileum anastomosed at the anal canal.
In the United States the Australian-born surgeon Victor Warren Fazio at the Cleveland Clinic and Roger Dozois[21][22] at the Mayo Clinic began publishing on the operation in the early 1980s greatly increasing its diffusion and there was generous co-operation among these units, St Mark's and colorectal departments in Canada (Zane Cohen),[23][24] France (Rolland Parc)[25] and Italy (Gilberto Poggioli).
[26][27][28] Nicholls' other contributions to coloproctology include aspects of rectal cancer related to staging, local surgery, and radiotherapy and his collaboration with Professor Michael Kamm in the field of incontinence.
During this time (from 1997 to 2001), Nicholls was additionally a member of the Specialist Advisory Committee in General Surgery for Higher Surgical Training in Great Britain and Ireland.
[34] He was appointed Professor of Colorectal Surgery in Imperial College London in 1997 and was Chairman of the Board of Trustees of Northwick Park Institute for Medical Research from 2008 to 2016.