Surg Endosc DOI 10.1007/s00464-014-3960-5
and Other Interventional Techniques
DYNAMIC MANUSCRIPT
A novel single-stapling technique for colorectal anastomosis: a pre-ligation single-stapling technique (L-SST) in a porcine model Hiroshi Takeyama • Hirofumi Yamamoto • Taishi Hata • Yusuke Takahashi • Masahisa Ohtsuka • Ryoji Nonaka • Akira Inoue • Atsushi Naito • Tae Matsumura • Mamoru Uemura • Junichi Nishimura • Ichiro Takemasa • Tsunekazu Mizushima • Yuichiro Doki • Masaki Mori Received: 25 June 2014 / Accepted: 25 October 2014 Ó Springer Science+Business Media New York 2014
Abstract Background In low anterior resections, anastomosis continues to present major problems. Although the singlestapling technique (SST) is considered to be superior to the double-staple technique (DST) in terms of leakage and stenosis, SST requires suturing, which is particularly difficult during laparoscopic surgery. A simpler and safer method of anastomosis is needed. In this study, we developed a pre-ligation SST (L-SST) that does not require suturing and evaluated the usefulness of L-SST in an ex vivo and an in vivo porcine model. Methods Porcine rectums were ligated using SurgiTieTM and sharply resected instead of using a linear stapler. The burst pressures of the closed rectums after using a linear stapler and SurgiTieTM (each group; n = 5) and the burst pressures of the anastomoses performed with L-SST and DST (each group; n = 4) were measured. During in vivo porcine laparoscopic surgery, we performed and evaluated the feasibility of L-SST. Results After completing the anastomosis with L-SST, the ligated portion using SurgiTieTM was completely removed. The stump closed using SurgiTieTM was much stronger than that closed using a stapler (131.2 and 25.6 mmHg, respectively; P = 0.01). The average burst pressure of the Electronic supplementary material The online version of this article (doi:10.1007/s00464-014-3960-5) contains supplementary material, which is available to authorized users. H. Takeyama H. Yamamoto (&) T. Hata Y. Takahashi M. Ohtsuka R. Nonaka A. Inoue A. Naito T. Matsumura M. Uemura J. Nishimura I. Takemasa T. Mizushima Y. Doki M. Mori Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan e-mail: [email protected]
anastomoses performed with L-SST was 33.8 mmHg, whereas that performed with DST was 30.5 mmHg. We did not find significant difference between these two groups (P = 0.88). We also confirmed the feasibility of L-SST in an in vivo porcine laparoscopic surgery model. Conclusion We developed a novel SST, the L-SST. We were able to perform L-SST successfully using an ex vivo porcine rectum and during in vivo porcine laparoscopic surgery. Keywords Single-stapling anastomosis (SSA) Singlestapled technique (SST) Double-stapling anastomosis (DSA) Double-stapling technique (DST) Laparoscopy Laparoscopic surgery Colorectal neoplasm SurgiTieTM
Low anterior resection (LAR) for lower rectal cancer is a highly technically demanding surgical procedure. Although LAR is a standard surgery, anastomotic leakage remains a problem [1, 2] despite that many techniques have been investigated in order to reduce the leakage rate [3]. Anastomotic leakage could lead to local recurrence and a worse prognosis [4]. Therefore, simpler and safer methods of anastomosis are desired and have been investigated. The current most prevalently used method used for colorectal anastomoses is the double-stapling technique (DST), which Knight and Griffen reported in 1980 [5–7]. However, DST has some drawbacks such as the lateral intersecting staple lines (the so-called dog ears), crossing point of the staplers, and multiple staplers firing. The dog ear, crossing point, and multiple staplers firing might lead to anastomotic leakage [8–12]. In addition, laparoscopic surgery, especially an intracorporeal operation, is technically more difficult than open surgery due to the width and limited articulation of the devices. Therefore, due to the use of
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relatively large stapling devices in the narrow pelvis, lower rectal transactions performed intracorporeally need often more than one linear stapler. On the other hand, the single-stapling technique (SST) also has the drawback that placement and fixture of the anvil head to the lower rectum is technically difficult, especially during laparoscopic surgery. In addition, opening of the remnant rectum during the process of placing and fixing the anvil head is often unavoidable, leading to spillage and contamination by bacteria. We thought that a simple closure of the lower rectum could overcome the drawbacks of both of DST and conventional SST. In this study, we developed a simple and useful method of SST using temporal pre-ligation. We named this technique the pre-ligated single-stapling technique (L-SST). This study was aimed at evaluating the feasibility and usefulness of L-SST.
to definitively cut the ligation portion away. Before reconstruction, the anvil head of a circular stapling device was placed and fixed in the oral colon with a purse-string suture. The anvil rod was connected to the anvil head and anastomosis using SST (Fig. 1D, E). The ligation portion was totally removed after firing of the EEA. With this method, the closed portion of the rectum using SurgiTieTM was totally removed after the firing of the EEA and did not remain in place during the healing process. Surgical procedure DST was performed using GIA 60 blue (Covidien) and EEA 28 or EEA 31. The closure of the rectum without a stapling device was performed using a SurgiTieTM. All procedures, including L-SST, were performed by experienced surgeons. Preparation of porcine rectum samples
Materials and methods Technique; L-SST anastomotic procedure The porcine rectum was ligated using a SurgiTieTM (Covidien, Westbury, MA, USA) close to the resection line, and the rectum was cut approximately 5 mm from the ligated portion (Fig. 1A). The shaft of the circular stapler was introduced through the anal side of the distal rectum (Fig. 1B). The anvil rod of a circular stapling device (EEA 28 or 31; Covidien) was pushed forward, puncturing the closed rectum near the ligated portion (Fig. 1C). Importantly, the penetration should be just close enough to the ligation portion
Fig. 1 Overview of the L-SST procedure. A The rectum is ligated just proximal to the cut end of the rectum using a SurgiTieTM. B The shaft of the circular stapler (EEA) was introduced through the anal side of the distal rectum. C The anvil rod of the circular stapler was pushed forward to puncture the closed intestine near the ligated portion of the stump. D, E The anvil rod is connected with the anvil head, and the anastomosis is then performed using a SST
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Porcine colon and rectum were obtained from Funakoshi (Osaka, Japan). Samples were bought from the slaughterhouse. The rectums were harvested immediately after slaughtering and transported to the laboratory within 24 h. Air leak pressure evaluation Air leak pressure testing was performed following a previously described method [9]. Each anastomosis was tested for air leakage pressure using the PG-100 N-102R-H (Copal Electronics Inc, Japan). A catheter connected to the instrument was inserted into the distal end of the colonic lumen at the level of the anastomosis. A ligature was
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applied in a proximodistal direction. The rectum was placed in a beaker containing water, and air was infused into the rectum. The pressure value at the point of air leakage, indicating the greatest resistance to pressure of the anastomosis (bubbles in the water), was recorded [13].
Usefulness of L-SST in the in vivo laparoscopic model We were able to perform L-SST in the in vivo porcine laparoscopic surgery model (Fig. 5 and Video 1). After anastomosis, we confirmed that the ligated portion was completely resected with the circular stapler (Video 2).
In vivo porcine laparoscopic surgery Discussion We performed an in vivo study using male pigs. This study was approved by the Institutional Animal Ethics Committee. Statistical analysis Statistical analysis was performed using the JMP9 program (SAS Institute, Cary, NC, USA). The air leak pressure measured after the use of each method was compared using Wilcoxon’s rank test. Statistical significance was defined as P \ 0.05.
Results Evaluation of the anastomoses We confirmed the staple line without a dog ear in the L-SST group and the staple line with a dog ear in the DST group (Fig. 2A, B). We did not find any apparent failures or defects in the staple line in either group. In all cases, the ligated portion with SurgiTieTM was completely removed and did not remain in the anastomosis (Fig. 2C). In addition, we measured the distance between the ligated portion and the resection line with a circular stapler (Fig. 2D). The average distance was 4.75 (±0.96) mm. Air leak pressure of the closed rectum using SurgiTieTM versus a staple Air leak pressures were measured in the SurgiTieTM group and stapled group. The air leak pressures in the SurgiTieTM group and the staple group were 131.2 (±21.2) and 25.6 (±5.9) mmHg, respectively (Fig. 3). The air leak pressure in the SurgiTieTM group was significantly higher than that in staple group (P = 0.01). Air leak pressure of anastomosis by L-SST and DST Air leak pressures were measured in the L-SST and DST groups. The air leak pressures in the L-SST and DST groups were 33.8 (±15.2) and 30.5 (±7.6) mmHg, respectively (Fig. 4). We did not find a significant difference between these two groups (P = 0.88).
In this study, we demonstrate the usefulness of L-SST in overcoming the drawbacks of both of DST and conventional SST. This novel technique was feasible and used successfully in an in vivo and ex vivo porcine model. We simply ligated and closed the rectum and cut the ligated portion away after firing the circular stapler, and confirmed that the ligated portion of the rectum was completely removed. Therefore, the final staple lines after L-SST are totally consistent with those of conventional SST. During the L-SST procedure, bursting of the closed stump using SurgiTieTM while introducing the circular stapler through the anal side of the distal rectum would be the major complication, which is most expected. However, although some authors have also noted that pressure resistance using LigaSureTM is significantly weaker than a stapler [14], the DST anastomoses after closure of the rectal stump in a previous in vivo porcine study using the LigaSureTM was performed successfully [15]. In this study, we measured the air leak pressure of the closed rectum between the SurgiTieTM group and the staple group. We found that the air leak pressure in the SurgiTieTM group was significantly higher than that in staple group. The rectal wall burst under pressures above approximately 150 mmHg; however, air leaks were not observed from the ligated portion. Closure of the rectum using SurgiTieTM seemed to be physically superior to that using a stapler in terms of air leak pressure. These results suggest that the closed portion using SurgiTieTM can withstand the pressure that occurs during the advance of the anvil shaft, and SurgiTieTM is sufficient to perform L-SST. Next, we measured the air leak pressure of the anastomoses between the L-SST and DST groups. There was no difference in the air leak pressure between the L-SST and DST groups. L-SST and DST are almost the same anastomoses performed with a circular stapler, except for the dog ear; therefore, this result was reasonable. However, the dog ear and crossing point were previously reported to be potentially vulnerable areas and could also lead to anastomotic leakage [8–10]. Furthermore, multiple staplers firing during DST could lead to an excessively long stapling line due to an inadequate cutting angle in many cases, which might contribute to anastomotic leakage [11, 12]. With L-SST, multiple stapling that can occur with SST could be avoided. Therefore, with L-SST, which has no
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Surg Endosc Fig. 2 The gross findings of the staple line and the resected stoma. A The gross findings of the staple line after L-SST and DST, respectively (left DST and right L-SST). B The gross findings of the staple line after L-SST and DST, respectively (above DST and below L-SST). There are no dog ears after the L-SST, whereas there are dog ears after the DST (yellow arrows). C The gross findings of resected stomas after DST (left) and L-SST (right). The distance between the edge of cut line and the ligated portion were measured (double-headed yellow arrows). The average of the distance was 4.75 mm (Color figure online)
Fig. 3 Ex vivo measurements of the air leak pressure the closed rectum using SurgiTieTM versus a stapler. A The overview of the experiment (above stapler and below SurgiTieTM). B The air leak pressures of the rectum closed using SurgiTieTM and the stapler were 131.2 (±21.2) and 25.6 (±5.9) mmHg, respectively. The air leak pressure of the rectum after using SurgiTieTM was significantly higher than that after using the stapler (P = 0.01, Mann–Whitney U test; n = 5 for each group)
crossing point, multiple staplers firing could be avoided, leading to better safety. We validated the usefulness of L-SST in an in vivo porcine laparoscopic surgery model and were able to easily perform the L-SST technique. After anastomosis, we confirmed that the ligation point was completely resected with a circular stapler. Although a conventional stapling device is relatively large and sometimes hard to operate, the ligation device is relatively smaller and easier to operate in the narrow space of the pelvis. Recently, reduced port
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Fig. 4 Ex vivo measurement of the air leak pressure of the anastomosis after L-SST and DST. A The overview of the experiment. B The air leak pressures after L-SST and DST were 33.8 (±15.2) and 30.5 (±7.6) mmHg, respectively. There were no significant differences between the two groups (P = 0.88, Mann– Whitney U test; n = 4 for each group)
surgery (RPS), including single-port surgery, has commonly been used. In these surgeries, intracorporeal operations are more limited, and an easier technique is preferred; therefore, L-SST might be useful for RPS. Previously, several devices and methods were reported to solve the problems of DST and SST. Modified DST is reported to be a safer anastomotic technique than conventional DCT [16]. However, these methods demand suturing during laparoscopic surgery, which is very difficult, especially in the narrow pelvic area. In fact, in the reported study, a Pfannenstiel skin incision was made to apply the stitches in the pelvic cavity using hand sutures under direct vision because of technical difficulties [16]. During robotic surgery using the da Vinci surgical system, for example, the operator is able to use articulating laparoscopic instruments with wrist motions that make suturing and knot
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Fig. 5 A representative view of the L-SST in an in vivo porcine laparoscopic surgery model. A We ligated the rectum using a SurgiTieTM. B The shaft of the circular stapler (EEA) was introduced through the anal side of the distal rectum. C The anvil rod of the
circular stapler was pushed forward to puncture the closed rectum near the ligated portion of the stump. D, E The anvil rod was connected to the anvil head, and the L-SST was then performed
tying easier [17, 18]. Operators were able to perform pursestring sutures using the robotic system. However, robotic systems are very expensive and not present in many centers. Moreover, opening the intestine is not completely avoided, leading to contamination with bacteria during the process of placing and fixing the anvil head. There are some limitations in this study. We did not evaluate L-SST in human specimens because resected specimens are very important for pathological diagnosis and we were not able to acquire a specimen. In addition, we did not evaluate mid-term and long-term results after the anastomosis. However, we feel that the results after anastomosis by L-SST would most likely mimic the results of conventional SST. Leak tests are the most objective test for assessing anastomosis techniques and are widely used to determine the robustness of the anastomoses [19–21]. This study was the first to demonstrate the novel L-SST in vivo and ex vivo in a porcine model. Although additional research is needed, this simple technique might be useful for colorectal surgery, especially for laparoscopic surgery.
References
Acknowledgments This study was supported by a Grant for young surgeon awards from the Japan Surgical Society (to H.Takeyama). Disclosures Drs. H. Takeyama, H. Yamamoto, T. Hata, Y. Takahashi, M. Ohtsuka, R. Nonaka, A. Inoue, A. Naito, T. Matsumura, M. Uemura, J. Nishimura, I. Takemasa, T. Mizushima, Y. Doki, and M. Mori have no conflicts of interest or financial ties to disclose.
1. Poon JT, Law WL (2009) Laparoscopic resection for rectal cancer: a review. Ann Surg Oncol 16:3038–3047 2. Cheung YM, Lange MM, Buunen M, Lange JF (2009) Current technique of laparoscopic total mesorectal excision (TME): an international questionnaire among 368 surgeons. Surg Endosc 23:2796–2801 3. Fujii S, Ota M, Yamagishi S, Kunisaki C, Osada S, Suwa H, Ichikawa Y, Shimada H (2010) A Y-shaped vinyl hood that creates pneumoperitoneum in laparoscopic rectal cancer surgery (Y-hood method.): a new technique for laparoscopic low anterior resection. Surg Endosc 24:476–484 4. Mirnezami A, Mirnezami R, Chandrakumaran K, Sasapu K, Sagar P, Finan P (2011) Increased local recurrence and reduced survival from colorectal cancer following anastomotic leak: systematic review and meta-analysis. Ann Surg 253:890–899 5. Cohen Z, Myers E, Langer B, Taylor B, Railton RH, Jamieson C (1983) Double stapling technique for low anterior resection. Dis Colon Rectum 26:231–235 6. Griffen FD, Knight CD, Sr., Whitaker JM, Knight CD, Jr (1990) The double stapling technique for low anterior resection. Results, modifications, and observations. Ann Surg 211: 745–751; discussion 751–742 7. Knight CD, Griffen FD (1980) An improved technique for low anterior resection of the rectum using the EEA stapler. Surgery 88:710–714 8. Brisinda G, Vanella S, Cadeddu F, Civello IM, Brandara F, Nigro C, Mazzeo P, Marniga G, Maria G (2009) End-to-end versus endto-side stapled anastomoses after anterior resection for rectal cancer. J Surg Oncol 99:75–79 9. Kawasaki K, Fujino Y, Kanemitsu K, Goto T, Kamigaki T, Kuroda D, Kuroda Y (2007) Experimental evaluation of the
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mechanical strength of stapling techniques. Surg Endosc 21:1796–1799 Marecik SJ, Chaudhry V, Pearl R, Park JJ, Prasad LM (2007) Single-stapled double-pursestring anastomosis after anterior resection of the rectum. Am J Surg 193:395–399 Leroy J, Jamali F, Forbes L, Smith M, Rubino F, Mutter D, Marescaux J (2004) Laparoscopic total mesorectal excision (TME) for rectal cancer surgery: long-term outcomes. Surg Endosc 18:281–289 Ito M, Sugito M, Kobayashi A, Nishizawa Y, Tsunoda Y, Saito N (2008) Relationship between multiple numbers of stapler firings during rectal division and anastomotic leakage after laparoscopic rectal resection. Int J Colorectal Dis 23:703–707 Bluett MK, Healy DA, Kalemeris GC, O’Leary JP (1986) Comparison of automatic staplers in small bowel anastomoses. South Med J 79:712–716 Salameh JR, Schwartz JH, Hildebrandt DA (2006) Can LigaSure seal and divide the small bowel? Am J Surg 191:791–793 Sanchez-De Pedro F, Moreno-Sanz C, Morandeira-Rivas A, TeniasBurillo JM, De Guzman CAR (2014) Colorectal anastomosis facilitated by the use of the LigaSure sealing device: comparative study in an animal model. Surg Endosc 28:508–514
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16. Kang J, Lee HB, Cha JH, Hur H, Min BS, Baik SH, Kim NK, Sohn SK, Lee KY (2013) Feasibility and impact on surgical outcomes of modified double-stapling technique for patients undergoing laparoscopic anterior resection. J Gastrointest Surg 17:771–775 17. Ruurda JP, Broeders IA (2003) Robot-assisted laparoscopic intestinal anastomosis. Surg Endosc 17:236–241 18. Stefanidis D, Wang F, Korndorffer JR Jr, Dunne JB, Scott DJ (2010) Robotic assistance improves intracorporeal suturing performance and safety in the operating room while decreasing operator workload. Surg Endosc 24:377–382 19. Myers SR, Rothermel WS Jr, Shaffer L (2011) The effect of tissue compression on circular stapler line failure. Surg Endosc 25:3043–3049 20. Demura Y, Ishikawa N, Hirano Y, Inaki N, Matsunoki A, Watanabe G (2013) Transrectal robotic natural orifice translumenal endoscopic surgery (NOTES) applied to intestinal anastomosis in a porcine intestine model. Surg Endosc 27:4693–4701 21. Sodergren M, Clark J, Beardsley J, Bryant T, Horton K, Darzi A, Teare J (2011) A novel flexible endoluminal stapling device for use in NOTES colotomy closure: a feasibility study using an ex vivo porcine model. Surg Endosc 25:3266–3272
and Other Interventional Techniques
DYNAMIC MANUSCRIPT
A novel single-stapling technique for colorectal anastomosis: a pre-ligation single-stapling technique (L-SST) in a porcine model Hiroshi Takeyama • Hirofumi Yamamoto • Taishi Hata • Yusuke Takahashi • Masahisa Ohtsuka • Ryoji Nonaka • Akira Inoue • Atsushi Naito • Tae Matsumura • Mamoru Uemura • Junichi Nishimura • Ichiro Takemasa • Tsunekazu Mizushima • Yuichiro Doki • Masaki Mori Received: 25 June 2014 / Accepted: 25 October 2014 Ó Springer Science+Business Media New York 2014
Abstract Background In low anterior resections, anastomosis continues to present major problems. Although the singlestapling technique (SST) is considered to be superior to the double-staple technique (DST) in terms of leakage and stenosis, SST requires suturing, which is particularly difficult during laparoscopic surgery. A simpler and safer method of anastomosis is needed. In this study, we developed a pre-ligation SST (L-SST) that does not require suturing and evaluated the usefulness of L-SST in an ex vivo and an in vivo porcine model. Methods Porcine rectums were ligated using SurgiTieTM and sharply resected instead of using a linear stapler. The burst pressures of the closed rectums after using a linear stapler and SurgiTieTM (each group; n = 5) and the burst pressures of the anastomoses performed with L-SST and DST (each group; n = 4) were measured. During in vivo porcine laparoscopic surgery, we performed and evaluated the feasibility of L-SST. Results After completing the anastomosis with L-SST, the ligated portion using SurgiTieTM was completely removed. The stump closed using SurgiTieTM was much stronger than that closed using a stapler (131.2 and 25.6 mmHg, respectively; P = 0.01). The average burst pressure of the Electronic supplementary material The online version of this article (doi:10.1007/s00464-014-3960-5) contains supplementary material, which is available to authorized users. H. Takeyama H. Yamamoto (&) T. Hata Y. Takahashi M. Ohtsuka R. Nonaka A. Inoue A. Naito T. Matsumura M. Uemura J. Nishimura I. Takemasa T. Mizushima Y. Doki M. Mori Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan e-mail: [email protected]
anastomoses performed with L-SST was 33.8 mmHg, whereas that performed with DST was 30.5 mmHg. We did not find significant difference between these two groups (P = 0.88). We also confirmed the feasibility of L-SST in an in vivo porcine laparoscopic surgery model. Conclusion We developed a novel SST, the L-SST. We were able to perform L-SST successfully using an ex vivo porcine rectum and during in vivo porcine laparoscopic surgery. Keywords Single-stapling anastomosis (SSA) Singlestapled technique (SST) Double-stapling anastomosis (DSA) Double-stapling technique (DST) Laparoscopy Laparoscopic surgery Colorectal neoplasm SurgiTieTM
Low anterior resection (LAR) for lower rectal cancer is a highly technically demanding surgical procedure. Although LAR is a standard surgery, anastomotic leakage remains a problem [1, 2] despite that many techniques have been investigated in order to reduce the leakage rate [3]. Anastomotic leakage could lead to local recurrence and a worse prognosis [4]. Therefore, simpler and safer methods of anastomosis are desired and have been investigated. The current most prevalently used method used for colorectal anastomoses is the double-stapling technique (DST), which Knight and Griffen reported in 1980 [5–7]. However, DST has some drawbacks such as the lateral intersecting staple lines (the so-called dog ears), crossing point of the staplers, and multiple staplers firing. The dog ear, crossing point, and multiple staplers firing might lead to anastomotic leakage [8–12]. In addition, laparoscopic surgery, especially an intracorporeal operation, is technically more difficult than open surgery due to the width and limited articulation of the devices. Therefore, due to the use of
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relatively large stapling devices in the narrow pelvis, lower rectal transactions performed intracorporeally need often more than one linear stapler. On the other hand, the single-stapling technique (SST) also has the drawback that placement and fixture of the anvil head to the lower rectum is technically difficult, especially during laparoscopic surgery. In addition, opening of the remnant rectum during the process of placing and fixing the anvil head is often unavoidable, leading to spillage and contamination by bacteria. We thought that a simple closure of the lower rectum could overcome the drawbacks of both of DST and conventional SST. In this study, we developed a simple and useful method of SST using temporal pre-ligation. We named this technique the pre-ligated single-stapling technique (L-SST). This study was aimed at evaluating the feasibility and usefulness of L-SST.
to definitively cut the ligation portion away. Before reconstruction, the anvil head of a circular stapling device was placed and fixed in the oral colon with a purse-string suture. The anvil rod was connected to the anvil head and anastomosis using SST (Fig. 1D, E). The ligation portion was totally removed after firing of the EEA. With this method, the closed portion of the rectum using SurgiTieTM was totally removed after the firing of the EEA and did not remain in place during the healing process. Surgical procedure DST was performed using GIA 60 blue (Covidien) and EEA 28 or EEA 31. The closure of the rectum without a stapling device was performed using a SurgiTieTM. All procedures, including L-SST, were performed by experienced surgeons. Preparation of porcine rectum samples
Materials and methods Technique; L-SST anastomotic procedure The porcine rectum was ligated using a SurgiTieTM (Covidien, Westbury, MA, USA) close to the resection line, and the rectum was cut approximately 5 mm from the ligated portion (Fig. 1A). The shaft of the circular stapler was introduced through the anal side of the distal rectum (Fig. 1B). The anvil rod of a circular stapling device (EEA 28 or 31; Covidien) was pushed forward, puncturing the closed rectum near the ligated portion (Fig. 1C). Importantly, the penetration should be just close enough to the ligation portion
Fig. 1 Overview of the L-SST procedure. A The rectum is ligated just proximal to the cut end of the rectum using a SurgiTieTM. B The shaft of the circular stapler (EEA) was introduced through the anal side of the distal rectum. C The anvil rod of the circular stapler was pushed forward to puncture the closed intestine near the ligated portion of the stump. D, E The anvil rod is connected with the anvil head, and the anastomosis is then performed using a SST
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Porcine colon and rectum were obtained from Funakoshi (Osaka, Japan). Samples were bought from the slaughterhouse. The rectums were harvested immediately after slaughtering and transported to the laboratory within 24 h. Air leak pressure evaluation Air leak pressure testing was performed following a previously described method [9]. Each anastomosis was tested for air leakage pressure using the PG-100 N-102R-H (Copal Electronics Inc, Japan). A catheter connected to the instrument was inserted into the distal end of the colonic lumen at the level of the anastomosis. A ligature was
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applied in a proximodistal direction. The rectum was placed in a beaker containing water, and air was infused into the rectum. The pressure value at the point of air leakage, indicating the greatest resistance to pressure of the anastomosis (bubbles in the water), was recorded [13].
Usefulness of L-SST in the in vivo laparoscopic model We were able to perform L-SST in the in vivo porcine laparoscopic surgery model (Fig. 5 and Video 1). After anastomosis, we confirmed that the ligated portion was completely resected with the circular stapler (Video 2).
In vivo porcine laparoscopic surgery Discussion We performed an in vivo study using male pigs. This study was approved by the Institutional Animal Ethics Committee. Statistical analysis Statistical analysis was performed using the JMP9 program (SAS Institute, Cary, NC, USA). The air leak pressure measured after the use of each method was compared using Wilcoxon’s rank test. Statistical significance was defined as P \ 0.05.
Results Evaluation of the anastomoses We confirmed the staple line without a dog ear in the L-SST group and the staple line with a dog ear in the DST group (Fig. 2A, B). We did not find any apparent failures or defects in the staple line in either group. In all cases, the ligated portion with SurgiTieTM was completely removed and did not remain in the anastomosis (Fig. 2C). In addition, we measured the distance between the ligated portion and the resection line with a circular stapler (Fig. 2D). The average distance was 4.75 (±0.96) mm. Air leak pressure of the closed rectum using SurgiTieTM versus a staple Air leak pressures were measured in the SurgiTieTM group and stapled group. The air leak pressures in the SurgiTieTM group and the staple group were 131.2 (±21.2) and 25.6 (±5.9) mmHg, respectively (Fig. 3). The air leak pressure in the SurgiTieTM group was significantly higher than that in staple group (P = 0.01). Air leak pressure of anastomosis by L-SST and DST Air leak pressures were measured in the L-SST and DST groups. The air leak pressures in the L-SST and DST groups were 33.8 (±15.2) and 30.5 (±7.6) mmHg, respectively (Fig. 4). We did not find a significant difference between these two groups (P = 0.88).
In this study, we demonstrate the usefulness of L-SST in overcoming the drawbacks of both of DST and conventional SST. This novel technique was feasible and used successfully in an in vivo and ex vivo porcine model. We simply ligated and closed the rectum and cut the ligated portion away after firing the circular stapler, and confirmed that the ligated portion of the rectum was completely removed. Therefore, the final staple lines after L-SST are totally consistent with those of conventional SST. During the L-SST procedure, bursting of the closed stump using SurgiTieTM while introducing the circular stapler through the anal side of the distal rectum would be the major complication, which is most expected. However, although some authors have also noted that pressure resistance using LigaSureTM is significantly weaker than a stapler [14], the DST anastomoses after closure of the rectal stump in a previous in vivo porcine study using the LigaSureTM was performed successfully [15]. In this study, we measured the air leak pressure of the closed rectum between the SurgiTieTM group and the staple group. We found that the air leak pressure in the SurgiTieTM group was significantly higher than that in staple group. The rectal wall burst under pressures above approximately 150 mmHg; however, air leaks were not observed from the ligated portion. Closure of the rectum using SurgiTieTM seemed to be physically superior to that using a stapler in terms of air leak pressure. These results suggest that the closed portion using SurgiTieTM can withstand the pressure that occurs during the advance of the anvil shaft, and SurgiTieTM is sufficient to perform L-SST. Next, we measured the air leak pressure of the anastomoses between the L-SST and DST groups. There was no difference in the air leak pressure between the L-SST and DST groups. L-SST and DST are almost the same anastomoses performed with a circular stapler, except for the dog ear; therefore, this result was reasonable. However, the dog ear and crossing point were previously reported to be potentially vulnerable areas and could also lead to anastomotic leakage [8–10]. Furthermore, multiple staplers firing during DST could lead to an excessively long stapling line due to an inadequate cutting angle in many cases, which might contribute to anastomotic leakage [11, 12]. With L-SST, multiple stapling that can occur with SST could be avoided. Therefore, with L-SST, which has no
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Surg Endosc Fig. 2 The gross findings of the staple line and the resected stoma. A The gross findings of the staple line after L-SST and DST, respectively (left DST and right L-SST). B The gross findings of the staple line after L-SST and DST, respectively (above DST and below L-SST). There are no dog ears after the L-SST, whereas there are dog ears after the DST (yellow arrows). C The gross findings of resected stomas after DST (left) and L-SST (right). The distance between the edge of cut line and the ligated portion were measured (double-headed yellow arrows). The average of the distance was 4.75 mm (Color figure online)
Fig. 3 Ex vivo measurements of the air leak pressure the closed rectum using SurgiTieTM versus a stapler. A The overview of the experiment (above stapler and below SurgiTieTM). B The air leak pressures of the rectum closed using SurgiTieTM and the stapler were 131.2 (±21.2) and 25.6 (±5.9) mmHg, respectively. The air leak pressure of the rectum after using SurgiTieTM was significantly higher than that after using the stapler (P = 0.01, Mann–Whitney U test; n = 5 for each group)
crossing point, multiple staplers firing could be avoided, leading to better safety. We validated the usefulness of L-SST in an in vivo porcine laparoscopic surgery model and were able to easily perform the L-SST technique. After anastomosis, we confirmed that the ligation point was completely resected with a circular stapler. Although a conventional stapling device is relatively large and sometimes hard to operate, the ligation device is relatively smaller and easier to operate in the narrow space of the pelvis. Recently, reduced port
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Fig. 4 Ex vivo measurement of the air leak pressure of the anastomosis after L-SST and DST. A The overview of the experiment. B The air leak pressures after L-SST and DST were 33.8 (±15.2) and 30.5 (±7.6) mmHg, respectively. There were no significant differences between the two groups (P = 0.88, Mann– Whitney U test; n = 4 for each group)
surgery (RPS), including single-port surgery, has commonly been used. In these surgeries, intracorporeal operations are more limited, and an easier technique is preferred; therefore, L-SST might be useful for RPS. Previously, several devices and methods were reported to solve the problems of DST and SST. Modified DST is reported to be a safer anastomotic technique than conventional DCT [16]. However, these methods demand suturing during laparoscopic surgery, which is very difficult, especially in the narrow pelvic area. In fact, in the reported study, a Pfannenstiel skin incision was made to apply the stitches in the pelvic cavity using hand sutures under direct vision because of technical difficulties [16]. During robotic surgery using the da Vinci surgical system, for example, the operator is able to use articulating laparoscopic instruments with wrist motions that make suturing and knot
Surg Endosc
Fig. 5 A representative view of the L-SST in an in vivo porcine laparoscopic surgery model. A We ligated the rectum using a SurgiTieTM. B The shaft of the circular stapler (EEA) was introduced through the anal side of the distal rectum. C The anvil rod of the
circular stapler was pushed forward to puncture the closed rectum near the ligated portion of the stump. D, E The anvil rod was connected to the anvil head, and the L-SST was then performed
tying easier [17, 18]. Operators were able to perform pursestring sutures using the robotic system. However, robotic systems are very expensive and not present in many centers. Moreover, opening the intestine is not completely avoided, leading to contamination with bacteria during the process of placing and fixing the anvil head. There are some limitations in this study. We did not evaluate L-SST in human specimens because resected specimens are very important for pathological diagnosis and we were not able to acquire a specimen. In addition, we did not evaluate mid-term and long-term results after the anastomosis. However, we feel that the results after anastomosis by L-SST would most likely mimic the results of conventional SST. Leak tests are the most objective test for assessing anastomosis techniques and are widely used to determine the robustness of the anastomoses [19–21]. This study was the first to demonstrate the novel L-SST in vivo and ex vivo in a porcine model. Although additional research is needed, this simple technique might be useful for colorectal surgery, especially for laparoscopic surgery.
References
Acknowledgments This study was supported by a Grant for young surgeon awards from the Japan Surgical Society (to H.Takeyama). Disclosures Drs. H. Takeyama, H. Yamamoto, T. Hata, Y. Takahashi, M. Ohtsuka, R. Nonaka, A. Inoue, A. Naito, T. Matsumura, M. Uemura, J. Nishimura, I. Takemasa, T. Mizushima, Y. Doki, and M. Mori have no conflicts of interest or financial ties to disclose.
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