[Clinical significance of intersphincteric resection related anatomy effect on surgical safety].

The anatomical studies of intersphincteric resection (ISR) have made remarkable progress in recent years. The anatomy of internal, external sphincter and hiatal ligament has been further understood. In this paper, the generation and functional mechanism of ISR related anatomy are described from the embryonic development process, and then the influence of hiatal ligament and internal sphincter on ISR surgery is analyzed respectively according to the anatomical characteristics. Finally, the correlation analysis of anatomical factors on the common problems of mucosal bleeding and instrument anastomosis in ISR is carried out. The objective of this paper is to improve the safety of ISR surgery by providing detailed anatomical explanations.

[Recognition of surgical anatomy for intersphincteric resection].

Intersphincteric resection (ISR) involves the anatomy of hiatal ligament, internal and external sphincter and conjoined longitudinal muscle. The hiatal ligament is actually a branch of the longitudinal muscle of rectum, shown as an uneven ring attached to the levator ani muscle. The internal sphincter is the end of the circular muscle of rectum which begins at the level of hiatal ligament formation. The distance from the upper boundary of internal sphincter to dentate line is significantly different among individuals. Although there is adipose tissue in the space between the internal and external sphincters, no evidence of mesentery structure in the anal canal is found as in the rectum. The conjoined longitudinal muscle is the remaining branch of the longitudinal muscle, whose return passes through the external sphincter and ends at the anococcygeal ligament/coccyx after reaching the anal margin. The synergistic action of conjoined longitudinal muscle and the hiatal ligament participates in the defecation process. The individualized difference of ISR-related anatomy affects the operation, especially the anastomosis.

[Mechanism and anatomy recognition of neurovascular bundle injury from different perspectives of transabdominal and transanal approach].

The neurovascular bundle (NVB) starts at the lateral angle of the seminal vesicle (the initial part), passes posterolateral of the prostate gland (the main part), and ends at the cavernous body of the penis (the cavernous part). In low rectal surgery, different transabdominal and transanal perspectives result in different NVB injury risks. In the perspective of transabdominal operation, the separation between the initial part of NVB and Denonvilliers fascia and the anatomical variation of the two lateral sides of Denonvilliers fascia increases the risk of NVB injury, and conformation separation may take into account the convenience of separationand the protection of NVB. In the perspective of transanal operation, when separating the main part with NVB and mesorectum, the perspective of the transanal, unidirection traction and excessive dissection increase the risk of NVB main exposure. Clear anatomical identification helps the protection of NVB in the transanal operation. At present, the medical evidence on the difference of NVB injury in different perspectives of transabdominal and transanal approach is still in need of relevant clinical researches.

[Anatomic factors and preventive techniques for anastomotic complications after transanal total mesorectal excision].

Whether the transanal total mesorectal resection (taTME) techniques increase the risk of anastomotic failure is inconclusive. This paper discusses the anastomotic problems of taTME from different aspects including anatomical factors and technical characteristics. In terms of the anatomic and physiological characteristics of the lower rectum, the Hiatal ligament and the density of the perirectal space is a disadvantage to the anastomosis of taTME, while the prolapse of the rectum may be a beneficial factor. Due to the unique technical characteristics of taTME, the main reason affecting its anastomosis at present is that the caudal space at the distal end is not sufficiently mobilized, especially for male and lower anastomosis. In addition, stapled anastomosis at the level of anorectal ring may cause more problems, while manual anastomosis at the lower level may bring better results.

Laparoscopic intersphincteric resection for low rectal cancer: comparison of stapled and manual coloanal anastomosis.

AIM: The study aim was to analyse the safety and feasibility of laparoscopic intersphincteric resection with stapled coloanal anastomosis for low rectal cancer. METHOD: Between March 2009 and August 2010, 22 patients underwent laparoscopic intersphincteric resection with a stapled coloanal anastomosis without a diverting ileostomy. The results were compared retrospectively with hand-sewn coloanal anastomoses performed between January 2001 and May 2009, which included 55 open and 38 laparoscopic intersphincteric resections. The morbidity comparison only included data relevant to the anastomosis. Function was compared using the Saito function questionnaire and the Wexner score and only involved data relevant to the laparoscopy. RESULTS: The anastomotic complication rates were similar for fistula, bleeding and neorectal mucosal prolapse (P = 0.526, P = 0.653 and P = 0.411, respectively). Anastomotic leakage and stricture formation of the stapled coloanal anastomosis were significantly lower than those of the hand-sewn coloanal anastomosis (P = 0.037 and P = 0.028, respectively). There were no significant differences in the Saito function questionnaire and the Wexner score between the stapled and hand-sewn coloanal anastomotic groups (all P > 0.05). CONCLUSION: Laparoscopic intersphincteric resection with a stapled coloanal anastomosis is technically feasible and is less likely to result in anastomotic leakage and stricture formation than a hand-sewn anastomosis.

Partial longitudinal resection of the anorectum and sphincter for very low rectal adenocarcinoma: a surgical approach to avoid permanent colostomy.

AIM: Abdominoperineal resection has been the standard procedure for low rectal cancer. The present study details a new technique, partial longitudinal resection of the anorectum and sphincter, and assesses the oncological and functional outcomes. METHOD: Between January 2004 and April 2008, 12 patients underwent partial longitudinal resection of the anorectum and sphincter for low rectal cancer. All patients underwent a diverting ileostomy and received biofeedback training before stoma closure. Functional results were assessed by vector manometry, Wexner constipation score and Wexner incontinence score. The quality of life (QoL) was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). RESULTS: There was no postoperative mortality and a R0 curative resection was confirmed in every case. Morbidity included anastomotic leakage in three patients, one of whom underwent reoperation, and stenosis in 11, which was successfully managed with dilatation. The patient who underwent reoperation was not included in the functional analysis. The 11 successful patients received biofeedback training for 1-4 months, and underwent ileostomy closure 6-12 months after surgery. No patient had severe faecal incontinence after stoma closure. The EORTC QLQ-C30 global health status and QoL scores at 12 months after stoma closure were 50.4 ± 24.3, similar to preoperation scores of 52.3 ± 25.6 (P = 0.927), and not significantly different to scores for the healthy control population of 63.4 ± 23.5 (P = 0.539). No patients developed local recurrence during the median observation period (35.5 months). One patient had distant metastases at 24 months, and underwent resection of the left liver. CONCLUSION: Curability and acceptable anal function can be obtained by partial longitudinal resection of the anorectum and sphincter in patients with very low rectal cancers. This technique is recommended as an alternative to abdominoperineal resection in patients with external sphincter muscle invasion or tumours located below the dentate line.