Rectal mobilisation is begun posteriorly by lifting the sigmoid up and forward to expose the avascular space in the posterior midline surface filled with are-olar tissue. However, the entrance to the avascular space is closed by the right and especially left branches of hypogastric nerve. Therefore, first it is necessary to separate both branches of hypogastric nerve from the visceral fascia. Electrocautery is used to develop the posterior avascular dissection plane staying anterior to the presacral fascia, sacral nerve plexus and median sacral vessels but posterior to the superior rectal artery and mesorectum up to S4 level from which the rectosacral fascia emerges. This fascia, determined as an area where the presacral fascia gives way to fascia propria of the rectum, is incised anterior to the coccyx. Mobilisation is completed at the level of lig. anococcigeum.
Anterior mobilisation is begun by continuing the previously made parallel incisions of peritoneum to meet in the midline at the deepest portion of rec-tovesical/rectovaginal pouch. In females, a relatively avascular plane along the rectovaginal septum is developed by electrocautery dissection under direct vision. In males, the plane posterior to Denonvillier's fascia and anterior to the rectum is developed by electrocautery dissection distally to the inferior margin of the prostate. Care is taken to avoid injury to the posterior wall of the bladder, seminal vesicles and prostate gland to avoid pelvic plexus injury. If removing the tumour localised at the anterior rectal wall, the approach is altered to include a posterior vaginal wall in women and possibly to include a portion or the whole of the prostate in men if direct invasion into contiguous structures is present.
The final step in rectal mobilisation is to complete the division of the so-called "lateral ligament". The "lateral ligament" on each side is exposed by holding the lateral surface of the rectum in the hand and retracting it to the opposite side of the pelvis. This technique enables surgeons to expose the place of intimate junction of pelvic plexus with the visceral fascia of the rectum. The intimate junction of these anatomic structures is provided by the nerves connecting the pelvic plexus with the rectum and by the branches of the median rectal artery passing through the plexus to the rectum. The performed anatomic investigations have demonstrated that the pronounced trunk of the median rectal artery is observed in 25% of cases . This allows retraction of the lateral wall of the rectum with the use of scissors by coagulation of the branches and even the non-pronounced trunk of median rectal artery. The division and ligation of the tissues by clamps is allowed as a last resort when the trunk of artery is pronounced, because, in such a situation, the pelvic plexus can be injured. Injury of pelvic plexus leads to the urogenital complications. If implementation of APR is required and the two-team approach can be utilised, the perineal team joins the operation.
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