Perioperative management - open intersphincteric rectal resection, with transanal colon pull-through and pouch formation

• Pathological changes of the rectum that are located up to 5cm above the anocutaneous line, or that would not provide the required safety margin to the aboral resection margin in the case of a suprasphincteric anastomosis as part of a low anterior rectal resection; the illustrated surgical technique is in the border area between low anterior rectal resection and abdominoperineal extirpation.
• The operation includes a total mesorectal excision with resection of the internal sphincter as well as a coloanal anastomosis under stoma protection.
• This sphincter-preserving surgical procedure that avoids amputation requires a neorectal reconstruction through a colon pouch procedure. This shows a positive effect on postoperative bowel function.

When choosing between continence-preserving surgery and extirpation, both oncological and functional aspects must be considered.

Despite the central importance of the surgery, interdisciplinary therapy planning in the context of a multidisciplinary tumor conference is particularly important for carcinoma of the lower third of the rectum. Thus, through the use of long-term radiochemotherapy, a significant tumor reduction, often even downstaging, can be achieved, and smaller aboral resection margins, up to 0.5 cm, can be accepted, which often makes preservation of the bowel continuity possible in the first place. However, larger safety margins are recommended for poorly differentiated tumors (G3, G4).

The most important prognostic factor after oncological interventions is the resection of the tumor and the lymphatic drainage area while maintaining a >1 mm wide distance to the circumferential resection margin. The circumferential resection margin (CRM) describes the smallest distance from the tumor to the lateral resection margin, regardless of whether it is the primary tumor or another intramesorectal tumor manifestation such as tumor-involved lymph nodes or extramural vascular invasion. A positive CRM is generally documented as a distance of 1 mm or less.

Both criteria (aboral and circumferential) resection margin are significantly more difficult to achieve in carcinomas of the lower third of the rectum than in higher located tumors, which is reflected in poorer specimens and in particular a higher local recurrence rate. The reason for this lies primarily in the anatomical peculiarities.

Continuity-restoring reconstructions should generally be protected by a protective stoma due to the high rate of insufficiencies of the coloanal or intersphincteric anastomoses.

In the illustrated example, it is a juxta-anal located carcinoma of the lower third of the rectum. A partial intersphincteric resection is performed up to the level of the dentate line. The anastomosis is performed after forming a coloplasty pouch as a coloanal hand suture. 

Functional Aspects

In addition to the technical feasibility from an oncological perspective, functional aspects are crucial for the decision on continence preservation in low-seated carcinomas. Continuity preservation is not necessarily equal to continence preservation. About half of all patients with a low anterior rectal resection develop a „low anterior resection syndrome“ (LARS), which is characterized by an increased stool frequency with fractionated emptying, urgent bowel urge, and incontinence for gas or liquid stool. In addition, many patients suffer from significant problems with bowel emptying, which also has a considerable negative impact on quality of life. Patients with continence-preserving resections and anastomoses ≤5 cm are more restricted in terms of quality of life than patients with higher located tumors. 

The pretherapeutic assessment of the later function is difficult. The functional result becomes more critical with every centimeter that moves the anastomosis closer to the dentate line. Even in cases of preexisting incontinence, one should exercise the greatest restraint regarding the performance of a continuity-preserving operation. The decision for or against continence preservation in low-seated rectal carcinoma for functional reasons is almost always an individual decision, which must be discussed openly with the patient before the surgery.

Neoadjuvant Radiation Therapy

Neoadjuvant radiation therapy can be administered with and without chemotherapy and is recommended according to the S3 guidelines for rectal carcinoma in UICC stages II (pT3-4 pN0) and III (pT1-4 pN+). 

Neoadjuvant radiochemotherapy (RCT) lasts about 6 weeks, followed by a therapy break of 6-8 weeks until surgery. 

Neoadjuvant short-term radiation (RT) is administered on 5 consecutive days. Here, the surgery takes place after 2-7 days. Since tumor downsizing is not to be expected, RCT is preferred for tumors that reach the enveloping fascia or are located near the sphincter.

27% of patients show a histological complete remission through RCT. These patients have a particularly good oncological prognosis. Since response assessment is difficult and requires a DRE (digital rectal examination), an endoscopy, and an MRI for detection, a „watch-and-wait“ strategy can only be applied to tumors up to 7cm from the anus and preferably in studies.

• severe comorbidity

Limited operability e.g. due to severe lung disease, heart failure, liver cirrhosis, etc.; whether this comorbidity represents a contraindication to surgery must be checked individually.

• Severe, pre-existing anal incontinence.

If there was already a severe anal incontinence in the medical history before the development of the rectal carcinoma, it should be considered in consultation with the patient whether a Hartmann procedure with a deep Hartmann stump or an abdominoperineal rectal extirpation with terminal descending colostomy represents the more sensible surgical procedure. The functional result becomes more critical with every centimeter that moves the anastomosis closer to the linea dentata. It should be noted that a well-manageable stoma offers a better quality of life than severe anal incontinence without a stoma.

• Sphincter infiltration or insufficient safety distance between the lower tumor edge and the distal resection margin

In this case, an abdominoperineal rectal extirpation must be performed. The same applies to the situation where, despite setting down at the level of the linea dentata, there is macroscopic or microscopic (frozen section) infiltration with tumor cells in the specimen. In this case, too, a switch to abdominoperineal rectal extirpation must be made to ensure oncologically sufficient radicality.

Clinical Examination, incl. rectal-digital examination. This already allows an assessment of the distance of the tumor to the anocutaneous line and allows evaluation of the tumor's mobility relative to the surroundings. 

Rectoscopy: Only rigid rectoscopy allows for exact tumor localization, ideally measured by the distance of the tumor to the dentate line or the distance of the tumor from the anus.

Biopsy: Preoperative histological confirmation of the tumor diagnosis is mandatory. Multiple biopsies should be taken, as carcinomas often arise from adenomas.

Complete Colonoscopy: Complete colonoscopy is required to diagnose and remove additional adenomas or to rule out a second carcinoma. If the tumor is not passable due to stenosis, a colon contrast enema, intraoperative colonoscopy, or virtual colonoscopy can be performed alternatively.

Abdominal Ultrasound: Liver ultrasound is performed to rule out liver metastasis. Alternatively, this examination can be replaced by computed tomography of the abdomen or magnetic resonance imaging.

Computed Tomography of the Pelvis: CT has no value for local staging. Its value lies in the detection of distant metastases.

Computed Tomography of the Thorax: For tumors of the lower rectal third, required to rule out lung metastases. Lung metastases occur more frequently in rectal carcinoma than in colon carcinoma. In low-seated carcinoma, hematogenous metastasis occurs via the inferior rectal plexus into the vena cava.

Positron Emission Tomography (PET): This procedure is usually not used in the primary diagnosis of rectal carcinoma, but is very suitable for differentiating locoregional recurrences from scars or inflammatory changes.

Decision Criterion CRM=circumferential resection margin

In recent years, the circumferential resection margin (CRM) has established itself as the most important prognostic parameter. Patients with close proximity of the enveloping fascia to the tumor have a higher local recurrence rate and poorer survival.

To select suitable patients for neoadjuvant RT or RCT, the following diagnostic criteria need to be worked out:

• Tumor height
• Transmural infiltration depth (T-stage)
• Presence of mesorectal tumor-involved lymph nodes (N-stage)
• Distance of the tumor or tumor-suspicious LN to the mesorectal fascia (CRM). CRM (“circumferential resection margin”) is the distance of the tumor extensions from the mesorectal enveloping fascia, which can be predicted very accurately by MRI.

Endosonography: Endosonography allows the clinical T-category to be determined with relatively high sensitivity and specificity, based on which, among other things, it must be decided whether neoadjuvant therapy is to be performed. Furthermore, endosonography allows the diagnosis of suspicious lymph nodes in some patients due to their size. Overall, it is inferior to MRI except in T1 tumors.

Thin-slice Magnetic Resonance Imaging of the Pelvis: Magnetic resonance imaging allows for even clearer delineation than endosonography of a tumor infiltrating into the mesorectum from the boundary lamella and allows the distance to this structure to be determined very precisely. This provides high predictive accuracy regarding T- and N-category and the expected tumor-free status at the circumferential resection margin. The tumor extension to the pelvic floor and anal sphincter apparatus and possible infiltration of the intersphincteric space should be assessed.

Note: The choice of the appropriate surgical procedure for carcinoma of the lower rectal third requires specific diagnostics. In this context, the clinical examination and an MRI specifically tailored to this tumor location are of particular importance.

In carcinomas of the lower rectal third, achieving a negative circumferential resection margin often depends not on the dissection plane along the mesorectal enveloping fascia, but distal to the mesorectum in the area where the intestinal wall is no longer enveloped by mesorectal fat and lies directly against the levator. Exact preoperative tumor staging is indispensable, especially for anal-near tumors with close contact to the pelvic floor and the striated sphincter musculature, for choosing the correct surgical procedure.

• Written informed consent from the patient
• Clarification of operability, if necessary, involvement of other departments for consultative assessment of operability.
• Anesthesiological presentation
• Informative discussion regarding stoma care and marking of a stoma exit site
• Due to the significantly increased insufficiency rate, a protective stoma should be created in every case.
• Since the protection occurs through fecal diversion, the colon must be flushed, otherwise the contents of the entire colon frame can still empty into the abdominal cavity in the event of an insufficiency. 
• Preoperative bowel preparation: The current data situation speaks for an antegrade bowel lavage with addition of topical antibiotics.
• Since the protection occurs through fecal diversion, the colon must be flushed, otherwise the contents of the entire colon frame can still empty into the abdominal cavity in the event of an insufficiency. 
• perioperative antibiotic prophylaxis
• Bladder catheter
• Gastric tube
• if necessary, neoadjuvant radio-/chemotherapy
• Shaving of the surgical area

• Necessity of creating a protective loop ileostomy
• Injury to adjacent structures/organs: bladder, urethra, ureter, seminal vesicles, prostate, vagina; spleen
• Bleeding/postoperative bleeding with use of donor blood/transfusions
• Wound infection/intra-abdominal abscess/infection
• Thrombosis/embolism
• Impairment of bladder and sexual function
• Anastomotic insufficiency
• Anastomotic stricture
• Fecal incontinence
• Imperative urge to defecate
• Fractionated bowel emptying
• if necessary, discussion and documentation of a possible extension of the operation depending on findings to abdominoperineal rectal extirpation 
• Revision surgeries

• Intubation anesthesia
• Epidural catheter

The positioning is performed in the lithotomy position. When positioning in the leg holders, care must be taken to ensure that the peroneal nerve at the fibular head is padded and that it lies as freely as possible. Both arms are positioned alongside. To prevent the patient from slipping during extreme positioning, a base should be chosen that provides a firm hold and, if necessary, shoulder supports should be attached.

1. The surgeon stands initially on the right side, the 1st assistant opposite. The 2nd assistant stands initially between the legs.
2. During the peranal procedure the surgeon sits between the legs and the 2nd assistant switches to the right side. 
3. The scrub nurse stands on the left side, the instrument table over the end of the left leg.

• Leg Holders and Shoulder Supports
• Lone Star Retractor™
• Abdominal Wall Retractor
• Silicone Drainage with Suture and Drainage Bag

Postoperative Analgesia: The postoperative treatment includes in particular a consistent pain therapy, which is usually ensured by means of an epidural catheter or via peripheral analgesics, or via systemic analgesic administration (opiates, non-steroidal anti-inflammatory drugs).
Follow the link here to PROSPECT (Procedures Specific Postoperative Pain Management).
Follow the link here to the current guideline Treatment of acute perioperative and posttraumatic pain.

Medical Follow-up: The focuses of postoperative treatment are in the first 1–2 days after the operation the recognition of complications such as secondary bleeding, respiratory insufficiency, cardiac decompensation, etc. In the further course of treatment, from the 3rd and 4th postoperative day, the monitoring and management of possible infections and their detection are in the foreground (e.g. urinary tract infection, pneumonia, wound infection, anastomotic insufficiency). As soon as the patient is able to do so, stoma care should be initiated and practiced to ensure a prompt discharge. 

Thrombosis Prophylaxis: In the absence of contraindications, due to the high risk of thromboembolism (major operative abdominal intervention in malignancy), low-molecular-weight heparin should be administered in prophylactic, possibly weight- or disposition risk-adapted dosage until full mobilization is achieved, in addition to physical measures. The continuation of medicinal thromboembolism prophylaxis for e.g. 6 weeks is discussed.
To be noted: Renal function, HIT II (history, platelet control)
Follow the link here to the current guideline Prophylaxis of venous thromboembolism (VTE).

Mobilization: A prompt mobilization to the sink and into the hallway, depending on the condition, should be aimed for.

Physiotherapy: In addition to breathing exercises, regular mobilization of the patient to the edge of the bed or into the armchair takes place depending on the condition and strength ratios.

Diet Build-up: The diet build-up can be carried out within the framework of Fast-Track concepts from the 1st postoperative day, especially in the presence of an ileostomy.

Stool Regulation: Stool regulation should, if it does not start spontaneously, be stimulated by means of prokinetics (e.g. Prostigmin s.c. or i.v.).

Inability to Work: Depending on convalescence, an inability to work of at least 4-6 weeks after the operation must be expected in the regular case.