Page 67 - Read Online

Page 2 of 12 Funahashi et al. Mini-invasive Surg 2018;2:27 I http://dx.doi.org/10.20517/2574-1225.2018.28

Keywords: Transanal rectal dissection, transanal total mesorectal excision, intersphincteric resection, sphincter-
preserving resection, anorectal function outcomes, oncologic outcomes

INTRODUCTION
[1,2]
In surgery for rectal cancer, total mesorectal excision (TME) and negative circumferential resection
[3,4]
margins are prerequisites for minimizing local tumor recurrence after surgery for rectal cancer. How-
ever, male sex, high body mass index, visceral obesity, a narrow pelvis, bulky tumor and an advanced T-stage
pose technical challenges during surgery due to poor visualization of the mesorectal planes, especially with
[8]
[5,6]
[7]
laparoscopic surgery . Actually, the ALaCart and ACOSOG Z6051 randomized controlled trials failed
to show the noninferiority of laparoscopic surgery compared with open surgery for oncologic outcomes.
Additionally, minimizing postoperative anorectal dysfunction has been a major matter in sphincter pres-
ervation for low-lying rectal cancer (LRC) near the anus. Intersphincteric resection (ISR) makes sphincter
[9]
preservation possible for many patients with LRC . Laparoscopic ISR has been shown to be more feasible
[10]
and beneficial than open ISR . Recently, a new approach, the transanal total mesorectal excision (TaTME),
has attracted increasing attention as a promising technique for rectal cancer patients who may be poor
candidates for total TME. A transanal approach has another benefit: the level of the distal resection margin
is determined as the first step in the anal canal, taking care to preserve the internal anal sphincter (IAS) as
much as possible for LRC near the anus.

[11]
More recently, TaTME has been shown to be feasible in a randomized trial in France , a case-matched
[13]
[12]
study and a meta-analysis . However, its feasibility for those of Asian race, including Japanese patients,
remains unclear. As the average body mass index in Japan increases each year [14,15] , the transanal approach
may represent a solution for obese Japanese patients with a narrow pelvis and a bulky mesorectum.
The aim of this study was to clarify the clinical feasibility of this new technique by analyzing the long-term
oncologic and functional outcomes after sphincter-preserving resection (SPR) combined with transanal
rectal dissection (TARD) under direct vision for both complete TME and preservation of the IAS as much
[16]
as possible .

METHODS
Patients
The study was approved by the ethics committee of Toho University Omori Medical Center (No. 17-41). In-
formed consent was obtained from all patients in this study. All patients who underwent laparoscopic and
open SPR combined with TARD for LRC from April 2003 to March 2012 were included in this prospective
observational cohort study. We evaluated 90 patients undergoing laparoscopic and open SPR at our insti-
tution for the feasibility of TARD for LRC. The inclusion criterion was LRC located ≤ 5 cm from the anal
verge. Patients of both sexes and various ages were included. The exclusion criteria for TARD included le-
sions classified as T4b or N2-3, lateral lymph-node involvement, and the presence of distant metastases. An
immediate conversion to an abdominoperineal resection (APR) was performed if we observed any tumor
invasion into the external anal sphincter or the levator ani muscle during the dissection of the internal
anal sphincter and external anal sphincter muscles.

Surgical technique
The surgical technique for transanal retrograde dissection of the low rectum has been described previ-
[13]
ously [Figure 1]. Briefly, the anal canal was exposed using a self-retaining retractor (Lone Star Retractor;
Lone Star Medical Products Inc., Houston, TX). The distal aspect of the canal at the lower margin of the
tumor was closed using purse-string sutures under direct visualization, and the anal canal was irrigated