Laparoscopic total mesorectal excision with urogenital fascia preservation for mid-low rectal cancer: Anatomical basis and clinical effect - Experimental research

BACKGROUND

Total mesorectal excision (TME) is conventionally performed according to Heald's principles through the so-called 'holy plane', between the visceral and parietal fasciae. However, urinary and sexual dysfunctions remain frequent postoperative complications. We proposed to preserve urogenital fascia (UGF) in TME, and this study aimed to clarify the anatomical basis of this technique and evaluate its efficacy and safety.

MATERIALS AND METHODS

Cadaveric dissection was performed on 26 pelvises, and laparoscopic TME with UGF preservation was performed in 212 patients with mid-low rectal cancer. The fasciae and spaces related to TME were observed and described, and the clinical effect of UGF-preserving TME was analyzed.

RESULTS

In the 26 cadavers, fascia propria of the rectum (FPR) presents as a fibrous capsule enveloping the mesorectum. UGF extends postero-laterally to the rectum, enveloping the hypogastric nerves and ureters. We demonstrated that the visceral fascia is actually the UGF, and FPR and visceral fascia (i.e. UGF) are two independent layers of fascia. Thus, FPR, UGF and parietal fascia form two avascular spaces behind the rectum. The plane ventral to the UGF is the real 'holy plane' for TME, rather than that dorsal to the UGF as is traditionally thought. Laparoscopic TME with UGF preservation was successfully performed in all 212 patients, with low perioperative complications (10.8%) and a low 3-year local recurrence rate (4.2%). Furthermore, the incidences of urinary and sexual dysfunctions at postoperative 6 months were only 6.1% and 10.8%, respectively.

CONCLUSION

The avascular plane between the FPR and UGF (i.e. visceral fascia) is the real 'holy plane'. Laparoscopic TME with UGF preservation is a feasible radical surgery for mid-low rectal cancer, with better protection of urinary and sexual functions.

[Inter-fascial dissection in laparoscopic colorectal cancer surgery: principles of retraction and exposure and techniques in fascial separation]

Colorectal surgery for malignancies has evolved into an era of careful and precise dissection along mesorectal or mesocolic fascia to achieve the so-called total mesorectal excision or complete mesocolic excision. The wide use of laparoscopic technique prompted more anatomical, histological, and embryological studies. This leads to a deeper and more precise understanding of fascial anatomy concerning colorectal surgery, though controversies exist. The complicated anatomy of multilayer parietal fasciae and dense adhesion between fasciae at specific sites still represent a major hindrance to perform a precise inter-fascial dissection. Colorectal surgeons should be familiar with the onion-like arrangement of the visceral and parietal fasciae. The dedicated assistants should provide three-directional traction and adjust the direction of forces timely in a manner that the resultant forces are always in a direction perpendicular to the fasciae that are to be dissected. The fixation of the mesorectum and the mesocolon to the pelvic and abdominal wall can also be exploited as a natural counter-retraction. To separate loosely attached visceral and parietal fasciae, the application of splitting forces on opposite fasciae or sliding the forceps along the interface will provide quick separation and maintenance of the integrity of the fasciae. In summary, careful attention to the direction and strength of three directional retractions on parietal and visceral fasciae will help stretch and open up the areolar surgical tissue plane, skillful maneuver in separation and dividing of the attachment of two fasciae will ensure a precise inter-fascial dissection and help achieve total mesorectal excision or complete mesocolic excision, reducing the risk of the residual of the mesentery and inadvertent injuries to adjacent tissues and autonomic nerves.

[Perirectal fascial anatomy and pelvic autonomic nerve preservation during the transanal total mesorectal excision]

The difficulty of transanal total mesorectal excision (TME) is to find the correct dissection plane of perirectal space. As a complex new surgical procedure, the fascial anatomic landmarks of transanal approach operation are more likely to be ignored. It is often found that dissection plane is false after the secondary injury occurs during the operation, which results in the damage of pelvic autonomic nerves. Meanwhile, the mesorectum is easily damaged if the dissection plane is too close to the rectum. Thus, the safety of oncologic outcomes could be limited by difficulty achieving adequate TME quality. The promotion and development of the theory of perirectal fascial anatomy provides a new thought for researchers to design a precise approach for transanal endoscopic surgery. Transanal total mesorectal excision based on fascial anatomy offers a solution to identify the transanal anatomic landmarks precisely and achieves pelvic autonomic nerve preservation. In this paper, the authors focus on the surgical experience of transanal total mesorectal excision based on the theory of perirectal fascial anatomy, and discuss the feature of perirectal fascial anatomy dissection and technique of pelvic autonomic nerve preservation during transanal approach operation.

Laparoscopic lateral lymph node dissection in two fascial spaces for locally advanced lower rectal cancer

BACKGROUND

The procedure for lateral lymph node (LLN) dissection (LLND) is complicated and can result in complications. We developed a technique for laparoscopic LLND based on two fascial spaces to simplify the procedure.

AIM

To clarify the anatomical basis of laparoscopic LLND in two fascial spaces and to evaluate its efficacy and safety in treating locally advanced low rectal cancer (LALRC).

METHODS

Cadaveric dissection was performed on 24 pelvises, and the fascial composition related to LLND was observed and described. Three dimensional-laparoscopic total mesorectal excision with LLND was performed in 20 patients with LALRC, and their clinical data were analyzed.

RESULTS

The cadaver study showed that the fascia propria of the rectum, urogenital fascia, vesicohypogastric fascia and parietal fascia lie side by side in a medial-lateral direction constituting the dissection plane for curative rectal cancer surgery, and the last three fasciae formed two spaces (Latzko's pararectal space and paravesical space) which were the surgical area for LLND. Laparoscopic LLND in two fascial spaces was performed successfully in all 20 patients. The median operating time, blood loss and postoperative hospitalization were 178 (152-243) min, 55 (25-150) mL and 10 (7-20) d, respectively. The median number of harvested LLNs was 8.6 (6-12), and pathologically positive LLN metastasis was confirmed in 7 (35.0%) cases. Postoperative complications included lower limb pain in 1 case and lymph leakage in 1 case.

CONCLUSION

Our preliminary surgical experience suggests that laparoscopic LLND based on fascial spaces is a feasible, effective and safe procedure for treating LALRC.

[Significance of the intact of the fascia propria in protection of pelvic plexus during total mesorectal excision]

Total mesorectal excision (TME) is the gold standard of surgical treatment for mid and low rectal cancer. It aims to improve the oncological outcomes as well as preserve anal sphincter, sexual and urinary function. Compared with sympathetic nerve injury alone, pelvic plexus and neurovascular bundle (NVB) injury has significant effect on postoperative sexual dysfunction, especially erectile function. Since the lateral surgical plane of TME is narrow and densely packed, dissecting outside the plane causes pelvic plexus injury, while dissecting inside it results in residual mesorectum. In this commentary, we review the research progress of lateral fascial anatomy of TME, and describe the anatomical characteristics of rectosacral fascia based on our previous research results. The prehypogastric fascia acts as a "fascia barrier" when dissecting the lateral space constantly from posterior to anterior. In addition, the pelvic plexus fuses with the prehypogastric fascia which is considered as the outer side layer of rectosacral fascia laterally. Thus, the rectosacral fascia should be dissected at the level of S4 vertebral body posterior to the rectum in an arc shape and then enter the superior-levator space. Before dissecting the lateral spaces, the anterior space of the rectum should be dissected first. After an "U" shape cutting of the Denonvilliers' fascia, the lateral space should be dissected from anterior to posterior. Finally, the lateral attachment of rectosacral fascia is transected to ensure the integrity of the mesorectum without damaging the pelvic plexus.

A comprehensive review of neuroanatomy of the prostate

Although oncologic efficacy is the primary goal of radical prostatectomy, preserving potency and continence is also important, given the indolent clinical course of most prostate cancers. In order to preserve and recover postoperative potency and continence after radical prostatectomy, a detailed understanding of the pelvic anatomy is necessary to recognize the optimal nerve-sparing plane and to minimize injury to the neurovascular bundles. Therefore, we reviewed the most recent findings from neuroanatomic studies of the prostate and adjacent tissues, some of which are contrary to the established consensus on pelvic anatomy. We also described the functional outcomes of radical prostatectomies following improved anatomical understanding and development of surgical techniques for preserving the neurovascular bundles.