Miles Irving

Carcinoma of the large bowel is a major cause of morbidity and mortality throughout the western world. Surgical resection remains the best option for cure and the earlier the diagnosis is made the better the outcomes. Carcinoma proximal to the sigmoid colon is managed by standard surgical techniques following oncological principles; resection and end to end anastomosis will leave the patient with continence mechanisms intact although sometimes a changed stool consistency.
Resection of tumours below the sigmoid colon encroaches on the pelvic floor and the rectal ampulla and as a consequence has the potential for impairing continence mechanisms. This is at its most obvious when the anal sphincters are removed as in the classical abdomino perineal excision of the rectum which was the traditional operation for excision of tumours in the distal third of the rectum but which left the patient with a permanent stoma.
Over the past two decades this operation has been replaced as the treatment of choice by restorative resections, principally anterior resection of the rectum, an operation that is characterised by increasing encroachment on the dentate line and the anal sphincters.
In considering the use of ultra low anastomoses in restorative resection one has to balance two different problems. Can resection of the tumour be accomplished without compromising oncological principles?, and in cases where sphincter preservation is the aim, can the anastomosis be safely constructed and continence maintained?. It will be recalled that continence is not only a function of sphincter activity but also stool consistency and neo rectal distensibility and capacity.
In this regard the new sphincter preserving operations have to be considered in terms of benefit and harm.
The above aspects are considered in the papers by Scripcariu et al and Vasilescu and Popescu who describe on the one hand their experience with restorative proctectomy and the complications resulting particularly from the distal anastomosis and in the case of the second paper the maintenance of continence associated with a colonic J pouch.
What can we learn from the literature published by those who have extensive experience of these operations? Such a review has recently been published by Tytherleigh and Mortenson (2003). In summary this reveals that restorative resection of the rectum not only allows oncological principles to be maintained but indeed suggests that it produces better results in this respect than abdomino perineal resection of the rectum.
These highly sophisticated operations are still undergoing development and assessment, as is the role of associated chemoradiotherapy, but it is already clear that the best results both in functional and oncological terms come from those who specialise in their performance. This means that specialist colo-rectal surgeons in referral centres should undertake them. This is in contrast to surgery for malignancy in the colon proximal to the rectum, including the sigmoid colon, which in most countries will, for practical purposes, remain in the hands of the trained abdominal surgeon.
Patients will welcome well-performed restorative proctectemy, as long it is associated with good residual continence. Thus pre-operative assessment of anal sphincter function, and care to avoid damage to the sphincters or their nerve supply during operation is essential. The role of the colonic pouch is till evolving but, as in the small series described by Vasilescu and Popescu, is showing promise in well-selected patients. This series also confirms the value of a temporary loop ileostomy in ultra low anastomoses.
However, although restorative proctectomy undoubtedly produces an improved quality of life compared with abdomino perineal excision of the rectum an interesting paper by Renner et al (1999) shows that in terms of continence, patients who underwent anterior resection with a higher anastomosis had a significantly better outcome than those who had undergone anterior resection with an ultra-low anastomosis.
Although abdominoperineal excision of the rectum can now be regarded as an out-dated operation for the vast majority of rectal cancers the last word has not been written on restorative proctectomy and careful controlled study of evolving techniques is still required.

References
1. Tytherleigh, M.G. and Mortensen, N.J.McC. - Options for sphincter preservation in surgery for low rectal cancer. British Journal of Surgery, 2003, 90:922.
2. Renner, K., Rosen, H.R, Novi, G., Hobling, N., Schiessel, R. - Quality of life after surgery for rectal cancer: do we still need a permanent colostomy? Dis Colon Rectum, 1999, 42:1160.

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