Unteres, kloakogenes Rektumviertel

[Paradoxical sphincters in the abdomen]

Nitric oxide molecules serve as neurotransmitters to relax smooth muscle tension in many parts of the body. In humans and other mammals they play an important role for correct smooth muscle function in unusual locations. We previously described this mechanism (Stelzner, Chirurg. doi:10.1007/s00104-014-2777-z, 2014) using the occlusive mechanism of the upper and lower esophageal sphincters as an example. Cells producing nitric oxide can be found in the gastric fundus, the anorectal continence organ, vesicourethraltract and also in the uterine cervix in the final trimester of pregnancy. In all these locations they serve as elements of anatomical sphincter structures that have a paradoxical function. These observations confirm the points made in the introduction of this article on the stretch sphincter mechanism of the lower esophageal sphincter and the treatment of gastroesophageal reflux disease by retensioning of the esophagus in the diaphragmatic hiatus. In particular, high-resolution esophageal manometry of the lower esophageal sphincter can easily detect every functional disturbance caused by gastric plication and such changes were to be expected based on what we described in articles I and II.

Anatomical considerations for transanal minimal-invasive surgery: the caudal to cephalic approach

AIM

Nerve-sparing surgery during laparoscopic rectal mobilization is still limited by anatomical constraints such as obesity, the narrowness of the male pelvis, an ultra low rectal cancer or all of these. The transanal approach for total mesorectal excision has overcome the shortcomings of limited access to the rectal 'no-man's land' close to the pelvic floor. The aim of this anatomical study was to define a roadmap of anatomical landmarks for the caudal to cephalic approach so as to standardize nerve-sparing rectal mobilization procedures.

METHOD

Macroscopic dissections of the pelvis in a caudal to cephalic direction were performed in eight alcohol-glycerol embalmed cadavers. A roadmap of anatomical landmarks was created at different levels of section to demonstrate the sites of nerve injury.

RESULTS

Extrinsic autonomic nerves to the urogenital organs and the internal sphincter muscle are closely adjacent to the lowest portion of the rectum above the pelvic diaphragm.

CONCLUSION

This anatomical guide for the pelvic surgeon should facilitate a safe and nerve-sparing dissection of the mesorectal plane with a meticulous overview of the lowest autonomic nerve fibres. New anatomical insights by a 'caudal to cephalic' approach to the 'no-man's land' should help overcome anatomical constraints of a narrow, obese and male pelvis during rectal mobilization procedures.

Ninety and still active in research

BACKGROUND

Here, we review Prof. Stelzner's career and scientific achievements, which include his personal attitude to genuine creative thinking and its application to surgery and research.

DISCUSSION

The stations of his clinical career are highlighted together with his excursions into philosophical and historical topics. From the vast number of publications and research activities, we describe major contributions to morphology including recent contributions through functional examination techniques. We reflect on his research on perianal fistulas. Modern-day understanding of continence of the anal sphincter apparatus and other visceral sphincter systems were fields of his research.

CONCLUSION

His efforts in comparative anatomy and morphology are commended. An open mind throughout his life with sharp scientific reasoning opened him a world of solid arguments based on evidence to prove his view, sometimes after decades. Exemplary are the discussions about the adenoma-carcinoma sequence or his views on anatomical structures limiting the spread of cancer cells. We note his continuing research activities well beyond normal pension age. At the age of over 90, he is still a very sought-after conference speaker.

[Autoregulatory growth control of adenomatous polyps and carcinogenesis in the colorectal region. Basics of tumor surgery Part I]

Autoregulatory growth control of adenomatous polyps in the colon and rectum is an important factor in the success of sphincter-sparing surgical resections. It is the basis for the coexistence of billions of somatic cells in multicellular organisms. Similar to normal mucosa, adenomatous polyps in the colorectum show autoregulatory growth control in their tissues. This applies whether they are differentiated or undifferentiated. In most cases, their growth and expansion is controlled throughout life. While colorectal adenomas have malignant potential, their transformation to cancerous lesions is exceedingly rare (e.g., in familial polyposis, or FAP, with a prevalence of only one in 10,000). It has been hypothesized that "fully developed adenomas" frequently are a prestage of colorectal cancer. However, convincing evidence on a molecular level that this so-called adenoma-carcinoma sequence indeed occurs in vivo is lacking. In contrast, there is good evidence that colorectal carcinogenesis is a microevolutionary process and that the irrevocable loss of autoregulatory growth control is one of its features. The most prominent homing area for colorectal cancer is the rectum. If the rectum is resected, metachronous cancer occurs only very rarely. The most distal quarter of the rectum is cloacal in origin and a pivotal structure for anorectal continence. It should be preserved whenever a more proximal location of the tumor makes this possible. These conclusions are based on our extensive case series and observations extending over several decades.

[Regional growth preferences in hereditary, synchronous, and metachronous colorectal carcinomas. Basics of tumor surgery Part II]

This article discusses the therapeutic importance of the loss of self-regulation of cell division in polypoid adenomas and in the cloacogenic, cancerophilic rectal segment. Regional growth preferences can observed in familial adenomatous polyposis (FAP) and ulcerative colitis, as in other diseases featuring a cancerous disposition on the mucosa. For example, rectal carcinomas are more common than colon carcinomas if one considers the total mucosal surface area at risk. Malignant changes do not occur randomly in existing adenomas of FAP patients, and the adenomas' cell division--as in other adenomas--is governed by some degree of self-regulation. In FAP patients undergoing proctocolectomy, preferred new growth areas for carcinomas include the duodenum and ileum. In patients with synchronous colorectal cancers, the rectum is more commonly affected than other colon segments. If the rectum is resected, metachronous carcinomas are exceedingly rare in the remaining colon segments. Clinical decisions about rectal resection must be informed by understanding of the importance of this organ for anorectal continence as well as the described growth of colorectal malignancies.