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SPHINCTER SAVING RADICAL RESECTIONS :
History:

Attempts on saving sphincter following resection for rectal cancer date back to Verneuil in 1873 and Kraske in 1885. Miles (1908) described the technique of abdominoperineal resection on the basis of describing the lymphatic spread in upward, lateral and downward direction. His view dominated for three decades Goligher in 1951 showed that there is no distal spread of the lymphatics that questioned the dominance of APR.

Sphincter preservation was through over and initially lesions upper third of rectum and rectosigmoid were operated by Sphincter preserving surgery, d'Allaines in 1956 introduced abdominosacral approach for resection. Dixon 1958 introduced the modern anterior resection. With time, sphincter preserving opera-tions were extended to cancers below the rectosigmoid and upper half of the rectum and with advent of circular stapling devices, sphincter preserving operations become possible for most cancers of the mid rectum. In 1970s with the introduction of coloanal anastomosis by Sir Aian Parks, most of the lesions in lower rectum were also subjected to sphincter preservation.

Changing Concepts for Sphincter Preservation : In adults, the rectum is about 15 cm long. For treatment purposes the rectum is divided into three seg-ments e.g. upper, middle and lower one third at 5 cm intervals from anal verge. Initially it was believed that at least 6-8 cm. of residual anorectum was needed for continence to be preserved and a distal resection margin of 5 cm was thought to be minimum. This concept led to restriction of sphincter preservation to lesions of upper and middle third rectum. Later on It was proved that continence could be preserved even if whole of the rectum is resected. Margin of2cms Is enough for favorable lesions i.e. welt differentiated node negative tumors and for poorly differentiated node positive tumors 5 cm attempted in favorable lesions.

Mile's operation (APR) was based on the view that lymphatic drainage of the rectum is in upward lateral and downward directions. This view was refuted by Goligher and it is now accepted that infralevator lymphatic drainage of rectum does not occur and thus majority of the rectal tumors can be removed in a man-ner that preserved sphincter complex.

During the 1980's two other advances in the technique of excision of the rectum significantly modified the operative approaches to rectal cancer namely total mesorectal excision (TME) and pelvic autonomic nerve preservation (ANP). The principle of TME with ANP is based on sharp dissection between the parietal and visceral planes of pelvic vie fascia. The technique ensures that the complete rectum and mesorectum are excised together with perirectal fat to achieve negative lateral margins. This technique has reduced local recurrence rates from the worldwide figures of thirty percent to 5-8 % .

Low Anterior Resection (LAR):
LAR is any recta} resection that requires extraperitoneal rectal mo-bilization with an extraperitoneal colorectal or ileorectal anastomosis.

Indications:
o Lesions at middle one third (5to10 cm from anal verge).
o Lesions of lower one third (0 to 5 cm from anal verge) are technically difficult but managed by stapled anastamosis.

Contraindications:
o Tumors located 4 cm or below from anal verge.
o Extremely bulky tumors.
o Fixation of tumorto pelvic wall.
o Obese men/women with narrow pelvis having low or mid rectal lesion.
o Medically incapacitated patient.
o Preoperative gross fecal incontinence is absolute contraindication for anterior resection.
o Any spread of tumor to the sphincter complex.
o Distant metastasis.

ANASTMOTIC TECH-NIQUES :
Suture Techniques :
Anastomosis can be done by single layer interrupted 4-0 polyglycolic acid or silk sutures. Posterior row sutures placed first. This can be accomplished In an end to end or end to side fash-ion where the end of colon should be closed with su-tures.

Stapling Techniques :
Stapling can be done by a singale staple technique using Circular Stapler (EEA by Auto Suture or CDH by Ethicon). After firing the stapler completeness of the anastomosis should be checked by examining the doughnuts of the proximal and distal margins. Alternatively a double staple technique can be used wherein prior to division of distal rectum, a TA-55/ Roticulator Stapler is fired beyond the lesion. Rectum is divided proximal to the stapler line and specimen is removed. Then a circular intraluminal stapler is applied to complete the anastomosis through the distal rectal staple line.

Abdominosacral resec-tion :
d'Allaines popularized this procedure. Patients with midrectal lesions 5-10 cms from anal verge are candidates for abdominosacral resection.

Abdomen is opened through oblique incision starting between left costal margin and the iliac crest, running parallel to inguinal ligament and curving across the rectus above the pubis. Left colon and rectum are mobilized through this incision. A transverse incision is made over the sacrococcygeal Joint, coc-cyx is disarticulated and excised opening is enlarged by bulk dissection and rectosigmoid stump is delivered through this wound. The lesion is excised and a single layered sutured / stapled anastomosis is done to restore the bowel continuity. Both the abdominal and sacral wounds are closed in layers.
Colo-anal Procedures:
The abdominal anal pull through technique was the first attempt at coloanal anastomosis but unreliable functional result prevented the routine use of this technique. In 1972 Parks described the endo-analcolo-anal anastomosis as a method of avoiding damage to the anal sphincter mechanism. Postoperative assessment at 12 to 18 months showed that nearly all patients achieved continence to solid stool, but control of liquid stool or flatus was variable.

There are two methods for colo-anal anastomosis-straight and colonic J'pouch anastomosis. Functional results following -straight colo-anal anastomosis are often disappointing because many patients suffer from bowel fre-quency, soiling even after a year of adaptation.

The limitations of the straight colo-anal anasto-mosis led to the development of the colonic J'pouch anastomosis (Lazorthes 1986). The colonic J'pouch is made by folding the colon and creating a side to side anastomosis with a linear cutting stapler Introduced through the apex of the pouch. The apex is anastomosed to the anus endoanally or by the double stapling technique. The function with the coIonic reservoir is better than with a straight colo-anal anastomosis.

LOCAL THERAPY:
HISTORY
Lisfranc first reported local excision of rectal carcinoma in 1826. Initially this minimal access approach was necessary, as major colonic resection was formidable surgical challenge. In 1885 Paul Kraske presented the trans sacral approach, to rectal lesions, Bevan (1917) introduced Transsphincteric approach, which was repopularised by York Mason In 1970. Papillon first reported the use of endocavitary irradiation in 1973. Strauss introduced electrocoagulation of rectal cancer in 1935. Initially majority of local excision were palliative, however, curative local excision of rectal tumor have been revived In recent years.

PATIENT SELECTION CRITERIA :
Preoperative Staging :
This is done by various in-vestigations like Digital Rectal Examination (DRE), Ultrasonography, CTScan, MR1 and more recently by Endoscopic Ultrasonography (EDS). Use of EUS can determine T stage of tumor with 90%.

Selection Criteria :
Tumor < 4cm in diameter.
Tumor involves < 40% of cir-cumference.
Proximal margin < 8 cm from dentate line.
No palpable perirectal nodes.
Tumor mobile within pelvis on DRE.
Low grade tumor(Gl ,G2)
EUS determined uT1, Low risk uT2

Transanal Excision:
Under general anesthesia, in jackknife position and appropriate exposure a full thickness excision of the bowel wall is undertaken with care to expose perirectal fat to confirm a full thickness excision of the bowel wall containing the tumor. Recurrence rate ob-served by this procedure Is less than 5%.

Transcoccygeal Excision:
Under general anesthesia with the patient in prone-jackknife position incision Is made adjacent to the sacrum and coccyx down to the upper border of the posterior aspect of external sphincter. A posterior proctotomy is performed and tumor is removed with 1 cm margin under direct vision. The advantage of posterior approach is that the immediate mesorectal tissue adjacent to the tu-mor is removed with the perirectal nodes.

Transsphincteric Excision:
The York-Mason transsphincteric approach to the lower rectum Involves complete division of the sphincters and the posterior wall of the rectum. After removing the tumor, the rectum, sphincters, and musculature are reapproximated In a care-ful stepwise fashion. Be-cause the exposure to the lower rectum during this procedure Is similar to that of the Kraske procedure but with an increased risk of incontinence, there are few indications for this technique.

Transanal Endoscopic Microsurgery (TEM) :
TEM is the most recent addition to the list of local excision techniques for rec-tum and lower colon. TEM allows access from the dentate line of the anus up to the lower sigmold colon. TEM is performed with the use of endoscopic microsurgical resectoscope under direct binocular vision full thickness bowel wall is excised with tumor and closure of the defect is done by primary suturing with the use of appropriately designed endoscopic microsurgical Instruments.

Endocavitary Irradiation:
Endocavitary Irradiation is a suitable alternative to curative surgical excision of selected rectal cancer and may also be employed for palliation patient medical unfit to undergo an operation.

Electrocoagulation :
Although not widely ac-cepted local treatment by electrocoagulation is spar-ingly used. A theoretical advantage of this technique is that it may be less likely to cause seeding of viable tumor cells. Disadvantages being lack of pathological specimen for staging, reliance on visual and tactile information confirming tumor eradication and need for repeated procedures.

LASER TREATMENT :
Laser have not generally been used In curative treatment of colon and rectal carcinomas. Laser treatment of rectal cancer is generally limited treatment of bleeding or obstructive tumors, either for palliation or to achieve decompression for preoperative bowel preparation.

PHOTODYNAMIC THERAPY (PDT):
Recently Photodynamic Therapy has been used for palliation and local cure of small tumors such as anastomotic recurrence or for small residual areas of tumor after incomplete excision by other local techniques such as laser treatment or a peranal excision.

CRYOSURGERY:
Use of Cryosurgery is lim-ited to recannalization of an obstructing tumor in elderly medically unfit patient pre-senting with subacte/acute obstruction as a palliative measure.

ADJUVANT THERAPY (RT+/CT) :
Use of Adjuvant Therapy i.e. radiotherapy alone or in combination with chemo-therapy alter a sphincter saving resection is usually Indicated In locally advanced T2, T3 tumors with positive nodal metastases defected pathologically In the specimen to decrease the loco regional tumor recurrence rate and Increase the disease free survival of the patient. Adjuvant Therapy does not seem to improve overall survival of the patient and do not have any effect on rate of distant-metastases In various randomized trials.

INDUCTION THERAPY (R.T.+/-C.T.) :
Induction therapy refers chemotherapy, radiation therapy or both delivered before a definitive surgical procedure to diminish the likelihood of pelvic recurrence and to alter the magnitude and scope of planned surgical procedure. Use of induction therapy downstages 78 to 83% of patients who are determined preoperative to need APR to undergo sphincter preserving surgery.