TECHNICAL NOTES
Transanal Endoscopic Proctectomy and Nerve Injury Risk: Bottom to Top Surgical Anatomy, Key Points M. M. Bertrand, M.D.1 • P. E. Colombo, M.D., Ph.D.1 • B. Alsaid, M.D., Ph.D.2 M. Prudhomme, M.D., Ph.D.3 • P. Rouanet, M.D., Ph.D.1 1 ICM Val D’Aurelle, Surgical Oncology Department, Montpellier, France 2 Laboratory of Anatomy Faculty of Medicine, University of Damascus, Damascus, Syria 3 Digestive Surgery Department, CHU de Nimes, University Montpellier 1, Nimes, France
ABSTRACT: The transanal approach for rectal resection is a promising approach, because it increases the circumferential radial margin, especially for difficult cases. Meanwhile, functional sequelae are frequent after rectal cancer surgery and are often due to neurological lesions. There is little literature describing surgical anatomy from bottom to top. We combined our surgical experience with our fetal and adult anatomical research to provide a bottom-up surgical description focusing on neurological anatomy (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A148). KEY WORDS: Total mesorectal excision; Anatomy; Hypogastric plexus; Denonvilliers fascia; Transanal minimally invasive surgery; Transanal.
T
echnical and anatomical difficulties have driven surgeons to develop a variety of innovative surgical procedures. As far as rectal surgery is concerned, their aim is to increase the rate of R0 resections and, at the same time, to ensure a better preservation of urinary, sexual, and anal functions. The transanal approach appears to be an effective approach to increase the circumferential radial margin especially in the case of overweight male subjects with a narrow pelvis. For these difficult patients and in the case of low rectal tumors, the transanal approach Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML and PDF versions of this article on the journal’s Web site (www.dcrjournal.com) Financial Disclosures: None reported. Correspondence: M. M. Bertrand, M.D., ICM Val d’Aurelle, 208 Avenue des Apothicaires, 34298 Montpellier Cedex 5, France, E-mail: Martin. [email protected] Dis Colon Rectum 2014; 57: 1145–1148 DOI: 10.1097/DCR.0000000000000187 © The ASCRS 2014 Diseases of the Colon & Rectum Volume 57: 9 (2014)
indeed represents an alternative to blunt dissection. The objective of this technical note is to describe the surgical anatomy of this technique, while focusing on the risk of nerve injury.
MATERIAL AND METHOD We combined our surgical experience1 with our fetal and adult anatomical research2–4 to provide a bottom-to-top surgical description.
SURGICAL TECHNIQUE The patient is placed in a lithotomy position. High ligation of the inferior mesenteric artery and complete mobilization of the splenic flexure are systematically performed under laparoscopy, either before or after the transanal endoscopic proctectomy. We use a 4 cm diameter and 15-cmlong transanal endoscopic operation (TEO) proctoscope with a laparoscopic CO2 insufflator (10 mm Hg) and a Harmonic scalpel (ETHICON endosurgery, Johnson and Johnson, Wokingham, Surrey, UK) for the transanal dissection. The transanal procedure concerns only the inferior and middle thirds of the rectum, because the upper third is dissected during the laparoscopic procedure. The anterior dissection goes up as far as opening the Douglas cul-desac, the posterior dissection until S2 and up to the lateral rectal ligament. It begins with a soft digital dilation of the anal sphincter and introduction of the proctoscope. Inferior Third
After anal exposure, the pectinate line is incised and a partial intersphincteric resection is made under direct vision by using a TEO device (Karl Storz GmbH & Co. KG, Tuttlingen, Germany) (see Video, Supplemental Digital Content 2, http://links.lww.com/DCR/A149) or after classical exposure of the anal canal. We usually stitch the d issected 1145
1146
anal canal to prevent spillage of colonic content and further avoid additional insufflations into the colon. As a consequence, the plane of dissection is supra levator ani (above the levator ani muscle). The pudendal nerve and its branches (dorsal nerve of the penis or of the clitoris), which are infra levator ani, are out of reach (Fig. 1). Anterior Dissection
It follows the intersphincteric plane. In its inferior part the external sphincter is connected to the bulbospongious muscle; from bottom to top, it is connected to the deep transverse perineal muscle as well as the urethral sphincter. Here, the risk of nerve injury is only limited to the autonomous nervous fibers of the inferior hypogastric plexus or eventually some somatic fibers of the pudendal nerve that pass through the external anal sphincter to innervate the smooth sphincter (Fig. 2). When removing the Denonvilliers fascia from its very low edge, nerve injuries can occur and will in turn affect the spongious nerve (Fig. 3). Others difficulties involve the dissection of the urethral cape, especially for low anterior tumors (Fig. 4). In the supine position, the first approach is horizontal, then vertical, after the urethral cape. The surgeon must be guided by the step of the bladder catheter. Lateral and Posterior Dissections
The dissection takes place in the intersphincteric space and then in the mesorectal plane in accordance with total mesorectal excision principles. At the lower level, there is no proper mesorectum because we are still in the anal canal; at this point, the presacral fascia covering the levator ani and the rectal visceral fascia are fused. The fatty mesorectum is entered from the bottom upward, and gas
Bertrand et al: Bottom to Top Anatomy for Transanal Approach
insufflation helps to divide the mesorectum “holly plane” from the presacral fascia. The real location of the posterior pelvic fascias is still debated. We consider that the Waldeyer fascia is formed by the fusion of the presacral fascia covering the levator ani and the rectal visceral fascia.5,6 As a consequence, it is divided just above the pelvic floor plane. Going upward, we often need to divide the rectosacral fascia that joins the posterior aspect of the mesorectum to the presacral fascia. The correct plane leaves a nice and shiny fascia on the mesorectal fat and is usually separated from the presacral fascia by loose areolar tissue. The efferent branches of the inferior hypogastric plexus (IHP) are well separated at that level and the only branches that could be injured are the ones directed toward the rectum and the inner sphincter that are both removed. Middle Third Anterior Dissection
The dissection is continued proximally in a circumferential pattern. The anterior dissection plane is the rectovaginal or rectoprostatic fascia (Denonvilliers fascia). The Denonvilliers fascia has an asymmetrical “Y” shape3; it is denser medially and looser laterally. It plays the role of a protective layer for the medial efferent branch of the IHP especially for the spongious nerve. The cavernous nerve is slightly angled and positioned to the front of the spongious nerve on the lateral face of the vagina or prostate; risks of lesions are thus less probable (Figs. 1 and 3). We think that the Denonvilliers fascia (DF) is distinct from the fascia recti. As a consequence, the plane posterior to it is safer7,8 (Figs. 2 and 3). In the case of large anterior tumors, the problem is
FIGURE 1. Three-dimensional reconstruction of a fetus of 21 weeks of gestation and macroscopic dissection of a female adult cadaver. Left, Left lateral view coxal bone and levator ani muscle removed. It shows the spacial distribution of the afferent and efferent branches of the inferior hypogastric plexus and pudendal nerve. Center, bottom view showing that the pudendal nerves branches are supralevator ani. Right, inner view of the left hypogastric plexus in a female adult cadaver. AS = anal sphincter; 1 = smooth sphincter innervation; 2 = striated sphincter innervation; B = bladder; CC = cavernous body of the clitoris; CN = cavernous nerve; DF = Denonvilliers fascia; DNC = dorsal nerve of the clitoris; EAS = external anal sphincter; HN = hypogastric nerve; IHP = inferior hypogastric plexus; LAM = levator ani muscle; M = mesorectum; PC = proximal communication; PN = pudendal nerve; PR = peritoneal reflexion; PSN = pelvic splanchnic nerve; R = rectum; S = sacrum; SN = spongious nerve; SS = smooth anal sphincter; StS = striated anal sphincter; Ur = urethra; US = urethral sphincter; USN = urethral sphincter nerve; VB = vestibular bulbs.
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FIGURE 2. Three-dimensional reconstruction of a fetus of 31 weeks of gestation, showing that the optimal plane for nerve preservation is behind the Denonvilliers fascia. Left, bottom view rectum removed. Right, bottom view rectum and posterior layer of the Denonvilliers fascia removed. The posterior layer of the Denonvilliers fascia plays a protective role for the neurovascular bundles. DF = Denonvilliers fascia; LAM = levator ani muscle; NVB = neurovascular bundles; PN = pudendal nerve branches; U = urethra; V = vagina.
totally different and the balance between oncological adequacy and nerve preservation makes this anatomical consideration rather theoretical, the priority being to ensure a clear circumferential radial margin. Dissection behind DF: The anterior dissection is performed on the same plane; the white posterior part of the DF is well identified. The neurovascular bundles relief can often be spotted posterolateral to the prostate covered by the posterior layer of the DF. The risk of nerves injuries is practically nil. Dissection in front of the DF: The part of the DF removed shall be stretched as much as possible and centered as much as possible to avoid lesions to the
neurovascular bundle that is posterolateral to the prostate/ vagina.9 The lateral part of the DF must be cut according to the tumor location. The closer the dissection is to the seminal vesicle, the higher the risk of nerve injuries. Here, the nerve branches are thin and difficult to identify. Neurological lesions in this area usually concern the spongious nerves or fine branches directed toward the rectum. Lateral Dissection
The principle of total mesorectal excision defines the plane on which the lateral dissection is to be performed. This plane is situated between the fascia recti and the
FIGURE 3. Three-dimensional reconstruction of a fetus of 31 weeks of gestation showing the optimal plane for nerve preservation, behind the Denonvilliers fascia. AB = anterior branch of the inferior hypogastric plexus; B = bladder; CN = cavernous nerve; DF = Denonvilliers fascia; IAS = internal anal sphincter; IHP = inferior hypogastric plexus; PB = posterior branch of the inferior hypogastric plexus; PN = pudendal nerve; PR = peritoneal reflexion; PSN = pelvic splanchnic nerve; R = rectum; SN = spongious nerve; U = urethra; US = urethral sphincter; V = vagina.
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Bertrand et al: Bottom to Top Anatomy for Transanal Approach
performed, sometimes with a J-pouch. A covering loop ileostomy is constructed in all cases. The transanal approach for rectal resection is promising. The use of a proctoscope (transanal endoscopic proctectomy) or of a reusable device (transanal minimally invasive surgery) determine the technique. Bottom-to-top dissection commands a perfect knowledge of perirectal surgical anatomy to avoid complications such as ureteral or nerve injuries. This technique must now be assessed to clarify its goals: shall it be conducted automatically on lower tumors or shall it be reserved for specific and complex cases, for instance, on anterior tumors located in the narrow pelvis of overweight men? FIGURE 4. Axial sections of a 12-week-old male fetus at the urethral cape level. A, Ubiquitous nerve immune-labeling S100. B, Antismooth actin immune-labeling. It shows the proximity between the rectum (R) and the urethral sphincter (US) at this level. The mesorectum (M) is thin at this level, and few nerve fibers are spotted (black stars).
levator ani muscle fascia. It is the location of the inferior part of the inferior hypogastric plexus. The inferior hypogastric plexus is situated in a virtual space between the levator ani muscle fascia and the fascia recti. The safest plane is the strict plane of the fascia recti; most neurological lesions probably occur at this level (Figs. 2 and 3). Posterior Dissection
It is conducted in the mesorectal plane, between the fascia recti and the presacral fascia. At the level of the middle third of the rectum, we are situated under the level of the inferior hypogastric plexus and particularly under the junction of the nervi erigentes with the IHP. There is no risk of nerve injury at this level; the most frequent error, however, is to go too deep, which would then cause a risk of presacral bleeding. Posteriorly, the mesorectal dissection is continued as far as the convexity of the sacrum allows it, most often until the S2-S3 junction. Here, the work area has been maximized by the pneumoperitoneum as well as by the addition of opposing perpendicular retraction to the direct plane of dissection by means of a separate forceps. The transanal proctectomy is completed and the TEO removed. The abdominal classical laparoscopic total mesorectal excision resection is easily finished. The specimens are removed either by a small suprapubic incision or through the anus, and a coloanal anastomosis is
REFERENCES 1. Rouanet P, Mourregot A, Azar CC, et al. Transanal endoscopic proctectomy: an innovative procedure for difficult resection of rectal tumors in men with narrow pelvis. Dis Colon Rectum. 2013;56:408–415. 2. Alsaid B, Karam I, Bessede T, et al. Tridimensional computerassisted anatomic dissection of posterolateral prostatic neurovascular bundles. Eur Urol. 2010;58:281–287. 3. Bertrand MM, Alsaid B, Droupy S, Benoit G, Prudhomme M. Biomechanical origin of the Denonvilliers’ fascia. Surg Radiol Anat. 2014;36:71–78. 4. Bertrand MM, Alsaid B, Droupy S, Benoit G, Prudhomme M. Optimal plane for nerve sparing total mesorectal excision, immunohistological study and 3D reconstruction: an embryological study. Colorectal Dis. 2013;15:1521–1528. 5. García-Armengol J, García-Botello S, Martinez-Soriano F, Roig JV, Lledó S. Review of the anatomic concepts in relation to the retrorectal space and endopelvic fascia: Waldeyer’s fascia and the rectosacral fascia. Colorectal Dis. 2008;10:298–302. 6. Crapp AR, Cuthbertson AM. William Waldeyer and the rectosacral fascia. Surg Gynecol Obstet. 1974;138:252–256. 7. Lindsey I, Warren BF, Mortensen NJ. Denonvilliers’ fascia lies anterior to the fascia propria and rectal dissection plane in total mesorectal excision. Dis Colon Rectum. 2005;48:37–42. 8. Kinugasa Y, Murakami G, Uchimoto K, Takenaka A, Yajima T, Sugihara K. Operating behind Denonvilliers’ fascia for reliable preservation of urogenital autonomic nerves in total mesorectal excision: a histologic study using cadaveric specimens, including a surgical experiment using fresh cadaveric models. Dis Colon Rectum. 2006;49:1024–1032. 9. Hasegawa S, Nagayama S, Nomura A, Kawamura J, Sakai Y. Multimedia article. Autonomic nerve-preserving total mesorectal excision in the laparoscopic era. Dis Colon Rectum. 2008;51:1279–1282.
Transanal Endoscopic Proctectomy and Nerve Injury Risk: Bottom to Top Surgical Anatomy, Key Points M. M. Bertrand, M.D.1 • P. E. Colombo, M.D., Ph.D.1 • B. Alsaid, M.D., Ph.D.2 M. Prudhomme, M.D., Ph.D.3 • P. Rouanet, M.D., Ph.D.1 1 ICM Val D’Aurelle, Surgical Oncology Department, Montpellier, France 2 Laboratory of Anatomy Faculty of Medicine, University of Damascus, Damascus, Syria 3 Digestive Surgery Department, CHU de Nimes, University Montpellier 1, Nimes, France
ABSTRACT: The transanal approach for rectal resection is a promising approach, because it increases the circumferential radial margin, especially for difficult cases. Meanwhile, functional sequelae are frequent after rectal cancer surgery and are often due to neurological lesions. There is little literature describing surgical anatomy from bottom to top. We combined our surgical experience with our fetal and adult anatomical research to provide a bottom-up surgical description focusing on neurological anatomy (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A148). KEY WORDS: Total mesorectal excision; Anatomy; Hypogastric plexus; Denonvilliers fascia; Transanal minimally invasive surgery; Transanal.
T
echnical and anatomical difficulties have driven surgeons to develop a variety of innovative surgical procedures. As far as rectal surgery is concerned, their aim is to increase the rate of R0 resections and, at the same time, to ensure a better preservation of urinary, sexual, and anal functions. The transanal approach appears to be an effective approach to increase the circumferential radial margin especially in the case of overweight male subjects with a narrow pelvis. For these difficult patients and in the case of low rectal tumors, the transanal approach Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML and PDF versions of this article on the journal’s Web site (www.dcrjournal.com) Financial Disclosures: None reported. Correspondence: M. M. Bertrand, M.D., ICM Val d’Aurelle, 208 Avenue des Apothicaires, 34298 Montpellier Cedex 5, France, E-mail: Martin. [email protected] Dis Colon Rectum 2014; 57: 1145–1148 DOI: 10.1097/DCR.0000000000000187 © The ASCRS 2014 Diseases of the Colon & Rectum Volume 57: 9 (2014)
indeed represents an alternative to blunt dissection. The objective of this technical note is to describe the surgical anatomy of this technique, while focusing on the risk of nerve injury.
MATERIAL AND METHOD We combined our surgical experience1 with our fetal and adult anatomical research2–4 to provide a bottom-to-top surgical description.
SURGICAL TECHNIQUE The patient is placed in a lithotomy position. High ligation of the inferior mesenteric artery and complete mobilization of the splenic flexure are systematically performed under laparoscopy, either before or after the transanal endoscopic proctectomy. We use a 4 cm diameter and 15-cmlong transanal endoscopic operation (TEO) proctoscope with a laparoscopic CO2 insufflator (10 mm Hg) and a Harmonic scalpel (ETHICON endosurgery, Johnson and Johnson, Wokingham, Surrey, UK) for the transanal dissection. The transanal procedure concerns only the inferior and middle thirds of the rectum, because the upper third is dissected during the laparoscopic procedure. The anterior dissection goes up as far as opening the Douglas cul-desac, the posterior dissection until S2 and up to the lateral rectal ligament. It begins with a soft digital dilation of the anal sphincter and introduction of the proctoscope. Inferior Third
After anal exposure, the pectinate line is incised and a partial intersphincteric resection is made under direct vision by using a TEO device (Karl Storz GmbH & Co. KG, Tuttlingen, Germany) (see Video, Supplemental Digital Content 2, http://links.lww.com/DCR/A149) or after classical exposure of the anal canal. We usually stitch the d issected 1145
1146
anal canal to prevent spillage of colonic content and further avoid additional insufflations into the colon. As a consequence, the plane of dissection is supra levator ani (above the levator ani muscle). The pudendal nerve and its branches (dorsal nerve of the penis or of the clitoris), which are infra levator ani, are out of reach (Fig. 1). Anterior Dissection
It follows the intersphincteric plane. In its inferior part the external sphincter is connected to the bulbospongious muscle; from bottom to top, it is connected to the deep transverse perineal muscle as well as the urethral sphincter. Here, the risk of nerve injury is only limited to the autonomous nervous fibers of the inferior hypogastric plexus or eventually some somatic fibers of the pudendal nerve that pass through the external anal sphincter to innervate the smooth sphincter (Fig. 2). When removing the Denonvilliers fascia from its very low edge, nerve injuries can occur and will in turn affect the spongious nerve (Fig. 3). Others difficulties involve the dissection of the urethral cape, especially for low anterior tumors (Fig. 4). In the supine position, the first approach is horizontal, then vertical, after the urethral cape. The surgeon must be guided by the step of the bladder catheter. Lateral and Posterior Dissections
The dissection takes place in the intersphincteric space and then in the mesorectal plane in accordance with total mesorectal excision principles. At the lower level, there is no proper mesorectum because we are still in the anal canal; at this point, the presacral fascia covering the levator ani and the rectal visceral fascia are fused. The fatty mesorectum is entered from the bottom upward, and gas
Bertrand et al: Bottom to Top Anatomy for Transanal Approach
insufflation helps to divide the mesorectum “holly plane” from the presacral fascia. The real location of the posterior pelvic fascias is still debated. We consider that the Waldeyer fascia is formed by the fusion of the presacral fascia covering the levator ani and the rectal visceral fascia.5,6 As a consequence, it is divided just above the pelvic floor plane. Going upward, we often need to divide the rectosacral fascia that joins the posterior aspect of the mesorectum to the presacral fascia. The correct plane leaves a nice and shiny fascia on the mesorectal fat and is usually separated from the presacral fascia by loose areolar tissue. The efferent branches of the inferior hypogastric plexus (IHP) are well separated at that level and the only branches that could be injured are the ones directed toward the rectum and the inner sphincter that are both removed. Middle Third Anterior Dissection
The dissection is continued proximally in a circumferential pattern. The anterior dissection plane is the rectovaginal or rectoprostatic fascia (Denonvilliers fascia). The Denonvilliers fascia has an asymmetrical “Y” shape3; it is denser medially and looser laterally. It plays the role of a protective layer for the medial efferent branch of the IHP especially for the spongious nerve. The cavernous nerve is slightly angled and positioned to the front of the spongious nerve on the lateral face of the vagina or prostate; risks of lesions are thus less probable (Figs. 1 and 3). We think that the Denonvilliers fascia (DF) is distinct from the fascia recti. As a consequence, the plane posterior to it is safer7,8 (Figs. 2 and 3). In the case of large anterior tumors, the problem is
FIGURE 1. Three-dimensional reconstruction of a fetus of 21 weeks of gestation and macroscopic dissection of a female adult cadaver. Left, Left lateral view coxal bone and levator ani muscle removed. It shows the spacial distribution of the afferent and efferent branches of the inferior hypogastric plexus and pudendal nerve. Center, bottom view showing that the pudendal nerves branches are supralevator ani. Right, inner view of the left hypogastric plexus in a female adult cadaver. AS = anal sphincter; 1 = smooth sphincter innervation; 2 = striated sphincter innervation; B = bladder; CC = cavernous body of the clitoris; CN = cavernous nerve; DF = Denonvilliers fascia; DNC = dorsal nerve of the clitoris; EAS = external anal sphincter; HN = hypogastric nerve; IHP = inferior hypogastric plexus; LAM = levator ani muscle; M = mesorectum; PC = proximal communication; PN = pudendal nerve; PR = peritoneal reflexion; PSN = pelvic splanchnic nerve; R = rectum; S = sacrum; SN = spongious nerve; SS = smooth anal sphincter; StS = striated anal sphincter; Ur = urethra; US = urethral sphincter; USN = urethral sphincter nerve; VB = vestibular bulbs.
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Diseases of the Colon & Rectum Volume 57: 9 (2014)
FIGURE 2. Three-dimensional reconstruction of a fetus of 31 weeks of gestation, showing that the optimal plane for nerve preservation is behind the Denonvilliers fascia. Left, bottom view rectum removed. Right, bottom view rectum and posterior layer of the Denonvilliers fascia removed. The posterior layer of the Denonvilliers fascia plays a protective role for the neurovascular bundles. DF = Denonvilliers fascia; LAM = levator ani muscle; NVB = neurovascular bundles; PN = pudendal nerve branches; U = urethra; V = vagina.
totally different and the balance between oncological adequacy and nerve preservation makes this anatomical consideration rather theoretical, the priority being to ensure a clear circumferential radial margin. Dissection behind DF: The anterior dissection is performed on the same plane; the white posterior part of the DF is well identified. The neurovascular bundles relief can often be spotted posterolateral to the prostate covered by the posterior layer of the DF. The risk of nerves injuries is practically nil. Dissection in front of the DF: The part of the DF removed shall be stretched as much as possible and centered as much as possible to avoid lesions to the
neurovascular bundle that is posterolateral to the prostate/ vagina.9 The lateral part of the DF must be cut according to the tumor location. The closer the dissection is to the seminal vesicle, the higher the risk of nerve injuries. Here, the nerve branches are thin and difficult to identify. Neurological lesions in this area usually concern the spongious nerves or fine branches directed toward the rectum. Lateral Dissection
The principle of total mesorectal excision defines the plane on which the lateral dissection is to be performed. This plane is situated between the fascia recti and the
FIGURE 3. Three-dimensional reconstruction of a fetus of 31 weeks of gestation showing the optimal plane for nerve preservation, behind the Denonvilliers fascia. AB = anterior branch of the inferior hypogastric plexus; B = bladder; CN = cavernous nerve; DF = Denonvilliers fascia; IAS = internal anal sphincter; IHP = inferior hypogastric plexus; PB = posterior branch of the inferior hypogastric plexus; PN = pudendal nerve; PR = peritoneal reflexion; PSN = pelvic splanchnic nerve; R = rectum; SN = spongious nerve; U = urethra; US = urethral sphincter; V = vagina.
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Bertrand et al: Bottom to Top Anatomy for Transanal Approach
performed, sometimes with a J-pouch. A covering loop ileostomy is constructed in all cases. The transanal approach for rectal resection is promising. The use of a proctoscope (transanal endoscopic proctectomy) or of a reusable device (transanal minimally invasive surgery) determine the technique. Bottom-to-top dissection commands a perfect knowledge of perirectal surgical anatomy to avoid complications such as ureteral or nerve injuries. This technique must now be assessed to clarify its goals: shall it be conducted automatically on lower tumors or shall it be reserved for specific and complex cases, for instance, on anterior tumors located in the narrow pelvis of overweight men? FIGURE 4. Axial sections of a 12-week-old male fetus at the urethral cape level. A, Ubiquitous nerve immune-labeling S100. B, Antismooth actin immune-labeling. It shows the proximity between the rectum (R) and the urethral sphincter (US) at this level. The mesorectum (M) is thin at this level, and few nerve fibers are spotted (black stars).
levator ani muscle fascia. It is the location of the inferior part of the inferior hypogastric plexus. The inferior hypogastric plexus is situated in a virtual space between the levator ani muscle fascia and the fascia recti. The safest plane is the strict plane of the fascia recti; most neurological lesions probably occur at this level (Figs. 2 and 3). Posterior Dissection
It is conducted in the mesorectal plane, between the fascia recti and the presacral fascia. At the level of the middle third of the rectum, we are situated under the level of the inferior hypogastric plexus and particularly under the junction of the nervi erigentes with the IHP. There is no risk of nerve injury at this level; the most frequent error, however, is to go too deep, which would then cause a risk of presacral bleeding. Posteriorly, the mesorectal dissection is continued as far as the convexity of the sacrum allows it, most often until the S2-S3 junction. Here, the work area has been maximized by the pneumoperitoneum as well as by the addition of opposing perpendicular retraction to the direct plane of dissection by means of a separate forceps. The transanal proctectomy is completed and the TEO removed. The abdominal classical laparoscopic total mesorectal excision resection is easily finished. The specimens are removed either by a small suprapubic incision or through the anus, and a coloanal anastomosis is
REFERENCES 1. Rouanet P, Mourregot A, Azar CC, et al. Transanal endoscopic proctectomy: an innovative procedure for difficult resection of rectal tumors in men with narrow pelvis. Dis Colon Rectum. 2013;56:408–415. 2. Alsaid B, Karam I, Bessede T, et al. Tridimensional computerassisted anatomic dissection of posterolateral prostatic neurovascular bundles. Eur Urol. 2010;58:281–287. 3. Bertrand MM, Alsaid B, Droupy S, Benoit G, Prudhomme M. Biomechanical origin of the Denonvilliers’ fascia. Surg Radiol Anat. 2014;36:71–78. 4. Bertrand MM, Alsaid B, Droupy S, Benoit G, Prudhomme M. Optimal plane for nerve sparing total mesorectal excision, immunohistological study and 3D reconstruction: an embryological study. Colorectal Dis. 2013;15:1521–1528. 5. García-Armengol J, García-Botello S, Martinez-Soriano F, Roig JV, Lledó S. Review of the anatomic concepts in relation to the retrorectal space and endopelvic fascia: Waldeyer’s fascia and the rectosacral fascia. Colorectal Dis. 2008;10:298–302. 6. Crapp AR, Cuthbertson AM. William Waldeyer and the rectosacral fascia. Surg Gynecol Obstet. 1974;138:252–256. 7. Lindsey I, Warren BF, Mortensen NJ. Denonvilliers’ fascia lies anterior to the fascia propria and rectal dissection plane in total mesorectal excision. Dis Colon Rectum. 2005;48:37–42. 8. Kinugasa Y, Murakami G, Uchimoto K, Takenaka A, Yajima T, Sugihara K. Operating behind Denonvilliers’ fascia for reliable preservation of urogenital autonomic nerves in total mesorectal excision: a histologic study using cadaveric specimens, including a surgical experiment using fresh cadaveric models. Dis Colon Rectum. 2006;49:1024–1032. 9. Hasegawa S, Nagayama S, Nomura A, Kawamura J, Sakai Y. Multimedia article. Autonomic nerve-preserving total mesorectal excision in the laparoscopic era. Dis Colon Rectum. 2008;51:1279–1282.
