Surg Today DOI 10.1007/s00595-013-0774-3
HOW TO DO IT
Technical tips for intersphincteric resection: how to take out the rectum Yoshito Akagi • Tetsushi Kinugasa • Yousuke Oka • Tomoaki Mizobe • Takefumi Yoshida • Kazuo Shirouzu
Received: 23 May 2013 / Accepted: 3 September 2013 Ó Springer Japan 2013
Abstract Intersphincteric resection (ISR) is an ideal technique that preserves the anus, regardless of whether the internal anal sphincter is removed. However, it is difficult to dissect the anterior wall of the rectum from the adjacent organs. We herein describe a safe and useful ISR technique which draws out the rectum through the anus. The intersphincteric space (ISS) between the internal and external anal sphincter muscles was first transabdominally dissected. Next, the transanal dissection was advanced into the ISS bilaterally from the posterior side without dissecting the anterior wall of the anal canal, and the sigmoid colon and rectum were drawn out through the anus. Dissection between the anterior wall of the rectum and prostate/vagina could be easily performed under direct vision. This technique enables the dissection without any risk of a positive surgical margin or unexpected bleeding, and avoids injury to adjacent organs. This technique seems to be a safe and useful dissection technique for approaching the anterior wall of the anal canal. Keywords Intersphincteric resection Intersphincteric space Perianal manipulation
and advanced surgical techniques. In 1994, Schiessel et al. [1] reported intersphincteric resection (ISR) followed by hand-sewn coloanal anastomosis (CAA), which differed from the conventional hand-sewn CAA described by Parks [2, 3]. The ISR is a unique technique which preserves the anus, regardless of whether the internal anal sphincter (IAS) is removed. Although this procedure has been becoming increasingly common as a treatment strategy for lower rectal cancer near the anus in European and Asian countries, the critical and difficult aspect of this procedure is the dissection of the anterior wall of the anal canal. Because the anterior wall of an anal canal with a tumor is easily injured during dissection, the surgical margin is more likely to be positive, which may cause local recurrence. In addition, the preoperative evaluation of anal canal invasion is not easy for cases with advanced cancer [4]. A safe and simple technique needs to be established as a standard procedure. We recently devised an ideal technique which draws out the rectum through the anus, as in abdominoperineal resection (APR), which assured clean dissection between the anal canal and prostate/vagina [5]. To the best of our knowledge, this original technique has not yet been reported. We propose this technique as a suitable and safe option for ISR.
Introduction Sphincter-preserving operations, such as low and/or ultralow anterior resection, are widely used to treat low rectal cancers with various mechanical auto-suture instruments
Y. Akagi (&) T. Kinugasa Y. Oka T. Mizobe T. Yoshida K. Shirouzu Department of Surgery, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan e-mail: [email protected]
Informed consent Each patient provided written informed consent after receiving a full explanation of this procedure, including the risks of anal dysfunction and local recurrence, and was given a free choice to undergo APR or ISR. The use of neoadjuvant chemoradiation (CRT) was not included in the consent. All protocols contained within this study were approved by the local institutional review board.
123
Surg Today
Surgical techniques A schematic diagram of the anatomy and surgical methods ISR can be performed when either a mechanical or conventional hand-sewn CAA is technically impossible for a
low rectal cancer located within 4 cm from the anal verge. A schematic diagram of the ISR procedure is shown in Fig. 1. When no invasion to the intersphincteric space (ISS) was present, ISR was chosen based on our previous pathological studies [6]. The ISR was classified into three types: total ISR (T-ISR), in which the entire IAS was removed at the intersphincteric groove (ISG), and partial and subtotal ISR (P-ISR, ST-ISR), in which the IAS was partially or subtotally removed, respectively, on or below the dentate line [7]. Transabdominal approach
Fig. 1 A schematic diagram of the ISR procedure. a P-ISR, the IAS was partially removed by cutting above the DL. b ST-ISR, the IAS was subtotally removed by cutting between the DL and ISG. c T-ISR, the entire IAS was removed by cutting at the ISG. Dissection of the ISS was started from the hiatal ligament transection after the TME approach. TME total mesorectal excision, IAS internal anal sphincter, EAS external anal sphincter, ISG intersphincteric groove, ISS intersphincteric space, PRM puborectal muscle, P-ISR, ST-ISR or TISR partial, subtotal or total intersphincteric resection
a
b
The sigmoid colon was mobilized, and the inferior mesenteric artery was cut at the origin of the aorta. The sigmoid colon was resected after confirming the presence of a sufficient blood supply. Then, the rectum was mobilized to the level of the puborectal muscle (PRM) using the techniques used for total mesorectal excision (TME) and autonomic nerve preservation [8, 9]. The posterior and lateral sides of the beginning of the anal canal were well exposed, after the hiatal ligament was then transabdominally transected using electrocautery (Fig. 1). The ISS was then dissected from the lateral side to advance between the PRM and proper muscle of the rectum using scissors and electrocautery (Fig. 2a). The IAS was sufficiently detached from the external anal sphincter (EAS) when the dissection of the ISS was advanced lower than the level of the dentate line.
C
anal orifice ISS
thread
d
anal orifice
anterior wall
EAS PRM EAS
rectum
rectum thread
Fig. 2 The transanal approach. a The posterior and lateral sides of the anal canal are well exposed. The ISS is then dissected from the lateral side and advanced between the PRM and proper muscle of the rectum using scissors and electrocautery. b The anal orifice of the distal cut end is closed to prevent cancer cell dissemination into the pelvic cavity after the circular incision of the anal canal. c The ISS is transanally dissected from the EAS by providing moderate traction on
123
rectum the thread used for anal orifice closure. d After 3/4 circumferential removal of the IAS except for the anterior wall, the tumor-bearing rectum is drawn out through the anus by taking hold of the cut end of the sigmoid colon. The anterior wall of the anal canal is dissected from the prostate or vagina under direct vision. EAS external sphincter, ISS intersphincteric space, PRM puborectal muscle
Surg Today
Transanal approach The ISG was easily identified by a digital examination, and a circular incision of the anoderm was subsequently initiated by electrocautery after washout and disinfection of the rectum. The anal orifice of the distal cut end was closed to prevent cancer cell dissemination into the anal canal (Fig. 2b). The ISS dissection was then started from the posterior wall of the anal canal, and was advanced bilaterally without dissecting the anterior wall (Fig. 2c). Producing moderate traction using the threads used for the anal orifice closure was effective for advancing the dissection. After 3/4 circumferential removal of the IAS except for the anterior wall, the tumor-bearing rectum was drawn out through the anus by taking hold of the cut end of the sigmoid colon. The ISS dissection was completed anteriorly, during which the rectum and anal canal were identified by inserting the index finger into the rectoprostatic or rectovaginal septum (Fig. 2d). The traction of the intestine enabled the structures between the anal canal and the genital organs to be distinguished. This manipulation facilitates the procedure at the border of the bulbocavernosus muscle. Once the anterior wall of the anal canal was completely detached from the prostate/vagina, the whole rectum could be removed without any difficulty.
Results Surgical outcomes and complications Between 2001 and 2011, ISR was curatively performed in 124 patients (77 males and 47 females) with a very low rectal cancer who might otherwise have been treated with abdominoperineal resection (APR). No patient underwent preoperative or postoperative chemoradiotherapy. The median age, body mass index (BMI) and tumor size was 65 years (range 32–81 years), 23 kg/m2 (range 16–33 kg/m2) and 40 mm (range 10–140 mm), respectively. The median distance from the anal verge to the distal edge of the tumor was 30 mm. The surgical outcomes are listed in Table 1. The distance from the anal verge to the anastomosis was 10 mm. The median blood loss was 448 ml. Neither tumor perforation nor unexpected bleeding was present during the surgery. Postoperative complications of Grade II or more as defined by Dindo et al. [10] occurred in 24 patients (19.4 %), as listed in Table 1. Those complications required treatments such as the administration of antibiotics, drainage or surgery. Anastomotic leakage, including an anovaginal fistula (one patient), occurred in seven patients (5.6 %). Urogenital dysfunction was found in two patients (1.6 %). There was no in-hospital mortality.
Table 1 Surgical outcomes Characteristic
Outcome [n = 124]
Distance from AV to tumor (mm)*
30 (10–40)
Anastomosis from AV (mm)*
10 (0–30)
Reconstruction (S/JP)
92/32
Operative duration (min)*
390 (220–690)
Blood loss (ml)*
448 (35–3800)
Transfusion
28 (23 %)
Incidence of R0/R1 operation
121 (97.6 %)/3
All complications Anastomotic leakage
24 (19.4 %) 7 (5.6 %)
Colonic necrosis
2
Ileostoma closure impossible Pelvic abscess
2 4 (5 %)
Small bowel obstruction
2
Sepsis
1
Anastomotic stenosis
4 (5 %)
Lower limb thrombosis
1
Urinary disorder
1
Sexual disorder (male only)
1
In-hospital mortality
none
ISR intersphincteric resection, S straight, JP J-pouch * Values are median (range)
With regard to the pathological findings, a circumferential resection margin (CRM) C1 mm (R0 operation) was achieved in 121 patients (97.6 %). We had no patients with R2 operations, defined as macroscopically positive CRM. A CRM \1 mm (R1 operation) was found in three patients (2.4 %) and one of those had a tumor located at the anterior wall. Postoperative recurrence Our oncologic outcomes have recently been reported [11]. In brief, postoperative recurrence developed in 20 (16.1 %) of the 124 patients who underwent curative ISR. Local recurrence was found in six patients (4.8 %), including three patients with lateral lymph node metastasis, and there were three patients with pelvic floor recurrence. We had no recurrence confined to only the anastomotic site. Distant metastasis occurred in 13 patients (10.5 %), including four patients with liver metastasis, eight patients with lung metastasis and one patient with both liver and lung metastases. The overall recurrence-free five-year survival rate was 81.7 %.
Discussion ISR is a unique and sophisticated surgical technique, because good surgical, oncological and functional outcomes are demanded despite resection of the IAS. The
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Surg Today
most critical and difficult aspect of this procedure is the dissection of the anal canal, especially the anterior wall. In a previous study reported by Schiessel, ISS dissection was performed upwards from the distal end of the IAS under transabdominal guidance by an assistant surgeon [1]. Although many studies on the oncological and functional outcomes after ISR have been reported, to the best of our knowledge, no specific description about the surgical technique has been reported elsewhere. Our new technique, which draws out the rectum through the anus, enabled a safe ISS dissection to be performed under direct vision. This surgical technique has been commonly used in APR to maintain negative CRM, and to avoid unexpected bleeding and organ injury. Careful dissection under direct vision may help surgeons prevent injury to the rectum and anal canal. Although some studies with a focus on laparoscopic ISR have recently been reported, these studies did not clearly explain how to dissect the anterior wall of the rectum and anal canal [12, 13]. Even if laparoscopic surgery is superior to open surgery in terms of the field of vision, it is difficult to dissect the narrow ISS without injury using a transabdominal approach. A previous study has described the difficulty of distinguishing the IAS from the anal canal structures (complex) because of the presence of many small veins [14]. More careful attention is also required to avoid electrocautery/ scissors insertion into a tumor located at the anterior wall. However, we did not experience any uncontrollable bleeding, unexpected organ injury or any other intraoperative complications using this technique. However, this technique is difficult in obese patients, or those with a narrow pelvis and narrow anal canal, and is more difficult for cases with a bulky tumor located at the anterior wall. In such cases, complications may be more likely to occur. Therefore, when this technique is not applicable for such patients, the ISS dissection must be more carefully advanced toward the abdominal cavity from the anus. This technique should be used as needed, and is very useful for maintaining negative CRM and avoiding organ injury. We believe that the major advantage of this approach is that it enables a safe ISS dissection to be performed at the anterior wall of the anal canal. Surgeons who perform ISR should be familiar with the anal canal anatomy. Acknowledgments This study was supported in part by a Grant-inAid (No. 14-13, 18-07) for Cancer Research from the Ministry of
123
Health, Labour and Welfare of Japan. The study has not been performed under any commercial sponsorship or grants. Conflict of interest declare.
The authors have no conflicts of interest to
References 1. Schiessel R, Karner-Hanusch J, Herbst F, Teleky B, Wunderlich M. Intersphincteric resection for low rectal tumors. Br J Surg. 1994;81:1376–8. 2. Parks AG, Percy JP. Resection and sutured colo-anal anastomosis for rectal carcinoma. Br J Surg. 1982;69:301–4. 3. Akagi Y, Kinugasa T, Shirouzu K. Intersphincteric resection for very low rectal cancer: a systematic review. Surg Today. 2013;43(8):838–47. 4. Bamba Y, Itabashi M, Kameoka S. Preoperative evaluation of the depth of anal canal invasion in very low rectal cancer by magnetic resonance imaging and surgical indications for intersphincteric resection. Surg Today. 2012;42:328–33. 5. Miles WE. A method of performing abdomino-perineal excision for carcinoma of the rectum and of the terminal portion of the pelvic colon (1908). CA Cancer J Clin. 1971;21:361–4. 6. Shirouzu K, Ogata Y. Histopathologic tumor spread in very low rectal cancer treated with abdominoperineal resection. Dis Colon Rectum. 2009;52:1887–97. 7. Saito N, Moriya Y, Shirouzu K, Maeda K, Mochizuki H, Koda K, et al. Intersphincteric resection in patients with very low rectal cancer: a review of the Japanese experience. Dis Colon Rectum. 2006;49:S13–22. 8. Healed R, Ryall R. Recurrence and survival after total mesorectal excision for rectal cancer. Lancet. 1986;28:1479–82. 9. Shirouzu K, Ogata Y, Araki Y. Oncologic and functional results of total mesorectal excision and autonomic nerve-preserving operation for advanced lower rectal cancer. Dis Colon Rectum. 2004;47:1442–7. 10. Dindo D, Demartines N, Clavien PA. Classification of surgical complications. A new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205–13. 11. Akagi Y, Shirouzu K, Ogata Y, Kinugasa T. Oncologic outcomes of intersphincteric resection without preoperative chemo radiotherapy for very low rectal cancer. Surg Oncol. 2013;22:144–9. 12. Funahashi K, Koike J, Teramoto T, Saito N, Shiokawa H, Kurihara A, et al. Transanal rectal dissection: a procedure to assist achievement of laparoscopic total mesorectal excision for bulky tumor in the narrow pelvis. Am J Surg. 2009;197:e46–50. 13. Fujimoto Y, Akiyoshi T, Kuroyanagi H, Konishi T, Ueno M, Oya M, et al. Safety and feasibility of laparoscopic intersphincteric resection for very low rectal cancer. J Gastrointest Surg. 2010;14:645–50. 14. Uchimoto K, Murakami G, Kinugasa Y, Arakawa T, Matsubara A, Nakajima Y. Rectourethralis muscle and pitfalls of anterior perineal dissection in abdominoperineal resection and intersphincteric resection for rectal cancer. Anat Sci Int. 2007;82: 8–15.
HOW TO DO IT
Technical tips for intersphincteric resection: how to take out the rectum Yoshito Akagi • Tetsushi Kinugasa • Yousuke Oka • Tomoaki Mizobe • Takefumi Yoshida • Kazuo Shirouzu
Received: 23 May 2013 / Accepted: 3 September 2013 Ó Springer Japan 2013
Abstract Intersphincteric resection (ISR) is an ideal technique that preserves the anus, regardless of whether the internal anal sphincter is removed. However, it is difficult to dissect the anterior wall of the rectum from the adjacent organs. We herein describe a safe and useful ISR technique which draws out the rectum through the anus. The intersphincteric space (ISS) between the internal and external anal sphincter muscles was first transabdominally dissected. Next, the transanal dissection was advanced into the ISS bilaterally from the posterior side without dissecting the anterior wall of the anal canal, and the sigmoid colon and rectum were drawn out through the anus. Dissection between the anterior wall of the rectum and prostate/vagina could be easily performed under direct vision. This technique enables the dissection without any risk of a positive surgical margin or unexpected bleeding, and avoids injury to adjacent organs. This technique seems to be a safe and useful dissection technique for approaching the anterior wall of the anal canal. Keywords Intersphincteric resection Intersphincteric space Perianal manipulation
and advanced surgical techniques. In 1994, Schiessel et al. [1] reported intersphincteric resection (ISR) followed by hand-sewn coloanal anastomosis (CAA), which differed from the conventional hand-sewn CAA described by Parks [2, 3]. The ISR is a unique technique which preserves the anus, regardless of whether the internal anal sphincter (IAS) is removed. Although this procedure has been becoming increasingly common as a treatment strategy for lower rectal cancer near the anus in European and Asian countries, the critical and difficult aspect of this procedure is the dissection of the anterior wall of the anal canal. Because the anterior wall of an anal canal with a tumor is easily injured during dissection, the surgical margin is more likely to be positive, which may cause local recurrence. In addition, the preoperative evaluation of anal canal invasion is not easy for cases with advanced cancer [4]. A safe and simple technique needs to be established as a standard procedure. We recently devised an ideal technique which draws out the rectum through the anus, as in abdominoperineal resection (APR), which assured clean dissection between the anal canal and prostate/vagina [5]. To the best of our knowledge, this original technique has not yet been reported. We propose this technique as a suitable and safe option for ISR.
Introduction Sphincter-preserving operations, such as low and/or ultralow anterior resection, are widely used to treat low rectal cancers with various mechanical auto-suture instruments
Y. Akagi (&) T. Kinugasa Y. Oka T. Mizobe T. Yoshida K. Shirouzu Department of Surgery, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan e-mail: [email protected]
Informed consent Each patient provided written informed consent after receiving a full explanation of this procedure, including the risks of anal dysfunction and local recurrence, and was given a free choice to undergo APR or ISR. The use of neoadjuvant chemoradiation (CRT) was not included in the consent. All protocols contained within this study were approved by the local institutional review board.
123
Surg Today
Surgical techniques A schematic diagram of the anatomy and surgical methods ISR can be performed when either a mechanical or conventional hand-sewn CAA is technically impossible for a
low rectal cancer located within 4 cm from the anal verge. A schematic diagram of the ISR procedure is shown in Fig. 1. When no invasion to the intersphincteric space (ISS) was present, ISR was chosen based on our previous pathological studies [6]. The ISR was classified into three types: total ISR (T-ISR), in which the entire IAS was removed at the intersphincteric groove (ISG), and partial and subtotal ISR (P-ISR, ST-ISR), in which the IAS was partially or subtotally removed, respectively, on or below the dentate line [7]. Transabdominal approach
Fig. 1 A schematic diagram of the ISR procedure. a P-ISR, the IAS was partially removed by cutting above the DL. b ST-ISR, the IAS was subtotally removed by cutting between the DL and ISG. c T-ISR, the entire IAS was removed by cutting at the ISG. Dissection of the ISS was started from the hiatal ligament transection after the TME approach. TME total mesorectal excision, IAS internal anal sphincter, EAS external anal sphincter, ISG intersphincteric groove, ISS intersphincteric space, PRM puborectal muscle, P-ISR, ST-ISR or TISR partial, subtotal or total intersphincteric resection
a
b
The sigmoid colon was mobilized, and the inferior mesenteric artery was cut at the origin of the aorta. The sigmoid colon was resected after confirming the presence of a sufficient blood supply. Then, the rectum was mobilized to the level of the puborectal muscle (PRM) using the techniques used for total mesorectal excision (TME) and autonomic nerve preservation [8, 9]. The posterior and lateral sides of the beginning of the anal canal were well exposed, after the hiatal ligament was then transabdominally transected using electrocautery (Fig. 1). The ISS was then dissected from the lateral side to advance between the PRM and proper muscle of the rectum using scissors and electrocautery (Fig. 2a). The IAS was sufficiently detached from the external anal sphincter (EAS) when the dissection of the ISS was advanced lower than the level of the dentate line.
C
anal orifice ISS
thread
d
anal orifice
anterior wall
EAS PRM EAS
rectum
rectum thread
Fig. 2 The transanal approach. a The posterior and lateral sides of the anal canal are well exposed. The ISS is then dissected from the lateral side and advanced between the PRM and proper muscle of the rectum using scissors and electrocautery. b The anal orifice of the distal cut end is closed to prevent cancer cell dissemination into the pelvic cavity after the circular incision of the anal canal. c The ISS is transanally dissected from the EAS by providing moderate traction on
123
rectum the thread used for anal orifice closure. d After 3/4 circumferential removal of the IAS except for the anterior wall, the tumor-bearing rectum is drawn out through the anus by taking hold of the cut end of the sigmoid colon. The anterior wall of the anal canal is dissected from the prostate or vagina under direct vision. EAS external sphincter, ISS intersphincteric space, PRM puborectal muscle
Surg Today
Transanal approach The ISG was easily identified by a digital examination, and a circular incision of the anoderm was subsequently initiated by electrocautery after washout and disinfection of the rectum. The anal orifice of the distal cut end was closed to prevent cancer cell dissemination into the anal canal (Fig. 2b). The ISS dissection was then started from the posterior wall of the anal canal, and was advanced bilaterally without dissecting the anterior wall (Fig. 2c). Producing moderate traction using the threads used for the anal orifice closure was effective for advancing the dissection. After 3/4 circumferential removal of the IAS except for the anterior wall, the tumor-bearing rectum was drawn out through the anus by taking hold of the cut end of the sigmoid colon. The ISS dissection was completed anteriorly, during which the rectum and anal canal were identified by inserting the index finger into the rectoprostatic or rectovaginal septum (Fig. 2d). The traction of the intestine enabled the structures between the anal canal and the genital organs to be distinguished. This manipulation facilitates the procedure at the border of the bulbocavernosus muscle. Once the anterior wall of the anal canal was completely detached from the prostate/vagina, the whole rectum could be removed without any difficulty.
Results Surgical outcomes and complications Between 2001 and 2011, ISR was curatively performed in 124 patients (77 males and 47 females) with a very low rectal cancer who might otherwise have been treated with abdominoperineal resection (APR). No patient underwent preoperative or postoperative chemoradiotherapy. The median age, body mass index (BMI) and tumor size was 65 years (range 32–81 years), 23 kg/m2 (range 16–33 kg/m2) and 40 mm (range 10–140 mm), respectively. The median distance from the anal verge to the distal edge of the tumor was 30 mm. The surgical outcomes are listed in Table 1. The distance from the anal verge to the anastomosis was 10 mm. The median blood loss was 448 ml. Neither tumor perforation nor unexpected bleeding was present during the surgery. Postoperative complications of Grade II or more as defined by Dindo et al. [10] occurred in 24 patients (19.4 %), as listed in Table 1. Those complications required treatments such as the administration of antibiotics, drainage or surgery. Anastomotic leakage, including an anovaginal fistula (one patient), occurred in seven patients (5.6 %). Urogenital dysfunction was found in two patients (1.6 %). There was no in-hospital mortality.
Table 1 Surgical outcomes Characteristic
Outcome [n = 124]
Distance from AV to tumor (mm)*
30 (10–40)
Anastomosis from AV (mm)*
10 (0–30)
Reconstruction (S/JP)
92/32
Operative duration (min)*
390 (220–690)
Blood loss (ml)*
448 (35–3800)
Transfusion
28 (23 %)
Incidence of R0/R1 operation
121 (97.6 %)/3
All complications Anastomotic leakage
24 (19.4 %) 7 (5.6 %)
Colonic necrosis
2
Ileostoma closure impossible Pelvic abscess
2 4 (5 %)
Small bowel obstruction
2
Sepsis
1
Anastomotic stenosis
4 (5 %)
Lower limb thrombosis
1
Urinary disorder
1
Sexual disorder (male only)
1
In-hospital mortality
none
ISR intersphincteric resection, S straight, JP J-pouch * Values are median (range)
With regard to the pathological findings, a circumferential resection margin (CRM) C1 mm (R0 operation) was achieved in 121 patients (97.6 %). We had no patients with R2 operations, defined as macroscopically positive CRM. A CRM \1 mm (R1 operation) was found in three patients (2.4 %) and one of those had a tumor located at the anterior wall. Postoperative recurrence Our oncologic outcomes have recently been reported [11]. In brief, postoperative recurrence developed in 20 (16.1 %) of the 124 patients who underwent curative ISR. Local recurrence was found in six patients (4.8 %), including three patients with lateral lymph node metastasis, and there were three patients with pelvic floor recurrence. We had no recurrence confined to only the anastomotic site. Distant metastasis occurred in 13 patients (10.5 %), including four patients with liver metastasis, eight patients with lung metastasis and one patient with both liver and lung metastases. The overall recurrence-free five-year survival rate was 81.7 %.
Discussion ISR is a unique and sophisticated surgical technique, because good surgical, oncological and functional outcomes are demanded despite resection of the IAS. The
123
Surg Today
most critical and difficult aspect of this procedure is the dissection of the anal canal, especially the anterior wall. In a previous study reported by Schiessel, ISS dissection was performed upwards from the distal end of the IAS under transabdominal guidance by an assistant surgeon [1]. Although many studies on the oncological and functional outcomes after ISR have been reported, to the best of our knowledge, no specific description about the surgical technique has been reported elsewhere. Our new technique, which draws out the rectum through the anus, enabled a safe ISS dissection to be performed under direct vision. This surgical technique has been commonly used in APR to maintain negative CRM, and to avoid unexpected bleeding and organ injury. Careful dissection under direct vision may help surgeons prevent injury to the rectum and anal canal. Although some studies with a focus on laparoscopic ISR have recently been reported, these studies did not clearly explain how to dissect the anterior wall of the rectum and anal canal [12, 13]. Even if laparoscopic surgery is superior to open surgery in terms of the field of vision, it is difficult to dissect the narrow ISS without injury using a transabdominal approach. A previous study has described the difficulty of distinguishing the IAS from the anal canal structures (complex) because of the presence of many small veins [14]. More careful attention is also required to avoid electrocautery/ scissors insertion into a tumor located at the anterior wall. However, we did not experience any uncontrollable bleeding, unexpected organ injury or any other intraoperative complications using this technique. However, this technique is difficult in obese patients, or those with a narrow pelvis and narrow anal canal, and is more difficult for cases with a bulky tumor located at the anterior wall. In such cases, complications may be more likely to occur. Therefore, when this technique is not applicable for such patients, the ISS dissection must be more carefully advanced toward the abdominal cavity from the anus. This technique should be used as needed, and is very useful for maintaining negative CRM and avoiding organ injury. We believe that the major advantage of this approach is that it enables a safe ISS dissection to be performed at the anterior wall of the anal canal. Surgeons who perform ISR should be familiar with the anal canal anatomy. Acknowledgments This study was supported in part by a Grant-inAid (No. 14-13, 18-07) for Cancer Research from the Ministry of
123
Health, Labour and Welfare of Japan. The study has not been performed under any commercial sponsorship or grants. Conflict of interest declare.
The authors have no conflicts of interest to
References 1. Schiessel R, Karner-Hanusch J, Herbst F, Teleky B, Wunderlich M. Intersphincteric resection for low rectal tumors. Br J Surg. 1994;81:1376–8. 2. Parks AG, Percy JP. Resection and sutured colo-anal anastomosis for rectal carcinoma. Br J Surg. 1982;69:301–4. 3. Akagi Y, Kinugasa T, Shirouzu K. Intersphincteric resection for very low rectal cancer: a systematic review. Surg Today. 2013;43(8):838–47. 4. Bamba Y, Itabashi M, Kameoka S. Preoperative evaluation of the depth of anal canal invasion in very low rectal cancer by magnetic resonance imaging and surgical indications for intersphincteric resection. Surg Today. 2012;42:328–33. 5. Miles WE. A method of performing abdomino-perineal excision for carcinoma of the rectum and of the terminal portion of the pelvic colon (1908). CA Cancer J Clin. 1971;21:361–4. 6. Shirouzu K, Ogata Y. Histopathologic tumor spread in very low rectal cancer treated with abdominoperineal resection. Dis Colon Rectum. 2009;52:1887–97. 7. Saito N, Moriya Y, Shirouzu K, Maeda K, Mochizuki H, Koda K, et al. Intersphincteric resection in patients with very low rectal cancer: a review of the Japanese experience. Dis Colon Rectum. 2006;49:S13–22. 8. Healed R, Ryall R. Recurrence and survival after total mesorectal excision for rectal cancer. Lancet. 1986;28:1479–82. 9. Shirouzu K, Ogata Y, Araki Y. Oncologic and functional results of total mesorectal excision and autonomic nerve-preserving operation for advanced lower rectal cancer. Dis Colon Rectum. 2004;47:1442–7. 10. Dindo D, Demartines N, Clavien PA. Classification of surgical complications. A new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205–13. 11. Akagi Y, Shirouzu K, Ogata Y, Kinugasa T. Oncologic outcomes of intersphincteric resection without preoperative chemo radiotherapy for very low rectal cancer. Surg Oncol. 2013;22:144–9. 12. Funahashi K, Koike J, Teramoto T, Saito N, Shiokawa H, Kurihara A, et al. Transanal rectal dissection: a procedure to assist achievement of laparoscopic total mesorectal excision for bulky tumor in the narrow pelvis. Am J Surg. 2009;197:e46–50. 13. Fujimoto Y, Akiyoshi T, Kuroyanagi H, Konishi T, Ueno M, Oya M, et al. Safety and feasibility of laparoscopic intersphincteric resection for very low rectal cancer. J Gastrointest Surg. 2010;14:645–50. 14. Uchimoto K, Murakami G, Kinugasa Y, Arakawa T, Matsubara A, Nakajima Y. Rectourethralis muscle and pitfalls of anterior perineal dissection in abdominoperineal resection and intersphincteric resection for rectal cancer. Anat Sci Int. 2007;82: 8–15.
