Since 1995, we have performed “neo-anus surgery”.
Introduction of
‘neoanus with a pudendal nerve anastomosis’ (NAPNA)
after abdominoperineal excision of the rectum
Chapter 2.
A path to develop a new operation to avoid colostomy (neoanus surgery)
The anal sphincter plays three important roles.
(1) To accordingly regulate contraction and relaxation.
(2) To sense the need to defecate
(3) To maintain contraction at rest.
This operation aims at making neo-anus play these roles by attaching the nerve regulating these functions (the pudendal nerve) to the newly created anal sphincter. This operation was put into practical use after basic experiments on animals and anatomical examination by quasi-operations on autopsied bodies were carried out.
A series of research until the establishment of this operation
(1) Animal experiments
Priceless sacrifice of experimental animals was necessary before application to the operations on humans. First of all, we would like to extend our sincere gratitude to the sacrificed animals.
The function of the anus is maintained by two kinds of anal sphincter, the internal anal sphincter originated from the muscle of the bowel and the external anal sphincter, a kind of skeletal muscle. The external anal sphincter is made of skeletal muscle, the same kind of muscle in the arms and legs, but has incomparable characteristics. It maintains continuous contraction without being aware of. This greatly serves the purpose and is indeed reasonable. This is a phenomenon called tonus. It can be proved by electromyogram demonstrating continuous contraction waves. Another characteristic is that a group of skeletal muscles at the bottom of the pelvic cavity, including the external anal sphincter, create the desire of defecation. For example, when a fetus pushes the muscle at the bottom of the pelvic cavity during delivery, the mother feels the desire to defecate or strain the muscle even though stools are not retained, which allows us to easily understand the mechanism. Furthermore, when abdominal pressure is elevated by squeezing and so on, contraction is enhanced unintentionally.
What stipulates these characteristics of the external anal sphincter that plays an important role in defecation and continence is the pudendal nerve. (There is a biological rule that characteristics of muscle are dependent on governance by nerves in higher forms of life than reptiles.) This operation aims at making skeletal muscle have the characteristics of the external anal sphincter after the pudendal nerve is sutured into it.
We carried out two different operations on animals and compared them. In one operation, after regular operation procedure for rectal cancer (resection of the rectum and anus), neo-anus was reconstructed with the sphincter that was made of the muscle the pudendal nerve was sutured into. In the other operation, neo-anus was reconstructed with the new sphincter that was made of the muscle with the originally existing nerve. As a result, in the group that the pudendal nerve was sutured, the new sphincter the pudendal nerve was sutured into had the characteristics of the external anal sphincter electrophysiologically, histochemically, and reflexively, and the defecation status was improved. Officially, a paper in English was published in a US academic journal ‘Surgery’ as follows:
Sato T, Konishi F. Functional perineal colostomy with pudendal nerve anastomosis following anorectal resection: An experimental study. Surgery 1996; 119: 641-651.
(2) Anatomical examination
Based on the experiments on animals, we carried out quasi-operations using human autopsied bodies to see if we could safely prepare new sphincter in humans, into which the pudendal nerve was sutured. As a result, we confirmed the safety of the operation anatomically. Officially, the results were published in a paper in a US academic journal ‘Surgery’.
Sato T, Konishi F, Kanazawa K. Functional perineal colostomy with pudendal nerve anastomosis following anorectal resection. A cadaver operation study on a new procedure. Surgery. 1997; 121: 569-74.
(3) Clinical application
Based on these examinations, the operation was ethically discussed in the hospital, and a clinical study started in 1995. In 1996, it was approved by the new ethical committee in the hospital, and clinical application is going on with refinement of the operation. The halfway results were officially published in US academic journals “Disease of the colon & rectum” and “Surgery”. And the long-term results were submitted to an academic journal.
Sato T, Konishi F, Kanazawa K. Anal sphincter reconstruction with a pudendal nerve anastomosis following abdominoperineal resection: Report of a case. Dis Colon Rectum 1997; 40: 1497-1503.
Sato T, Konishi F, Ueda K, Kashiwagi H, Kanazawa K, Nagai H. Physiological anorectal construction with pudendal nerve anastomosis and a colonic S-pouch after abdominoperineal resection: Report of 2 successful cases. Surgery 2000; 128: 116-120.
Preface To avoid colostomy (stoma), there is a neoanus surgery.
Chapter 1. Comments on rectal cancer for neoanus surgery
Chapter 2 A path to develop a new operation to avoid colostomy (neoanus
surgery)
Chapter 3. Outlines of the operation avoiding colostomy
Chapter 4. Live without a stomaChapter 5 Miscellaneous with self-introductionChapter 6 BibliographyLinkCorrespondence to:
Tomoyuki Sato M.D., Ph.D.
Assistant Professor, Center for Clinical Medicine and Research, International University of Health and Welfare
Iguchi, Nishinasuno-machi, Nasu-gun, Tochigi-ken, Japan
Email address: tomosato@iuhw.ac.jp
Fax: to Dr. Sato +81-287-39-3001
or
Tomoyuki Sato M.D., Ph.D. Department of Surgery, Jichi Medical School
3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi-ken, 329-0498, Japan
Email address: tomoyuki@jichi,ac.jp
fax: +81-285-44-3234
Link to the Japanese website of the stomaless surgery (Neoanus)