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358. The Young Rectal Cancer Patient
840 the study is surgico-anatomical investigation of connective tissue structures and spaces, surrounding the low rectum and anal canal/ anorectum/ with emphasis to locally advanced rectal cancer surgery and staging. Material and methods: Materials from 15 fresh, 15 embalmed cadavers and 4 human fetuses (17-19 weeks) were dissected. Intraoperative investigations during 50 radical operations for locally advanced low rectal cancer were performed. Histological sections from the cadavers, fetuses and the resected operative specimens were examined. Results: Rectal adventitia (’mesorectum’) and rectal fascia are situated around the extraperitoneal part of the rectum. Behind them is situated retrorectal space. Rectosacral fascia is situated in the lower part and lateral rectal ligaments in the lateral parts of this space. More dorsally are encountered internal and external layer of urogenital fascia, which enveloped pararectal space, including hypogastric nerves. Presacral space is behind with sacral venous plexus and sympathetic trunks in it. On the lateral side the rectal fascia is connected with pararectal pelvic space by lateral ligament. In front, the rectal fascia is part of recto-urogenital septum and is separated to peritoneoperineal fascia by the prerectal space. On the level of anorectal junction there is fusion of rectal, urogenital and superior diaphragmatic pelvic fascia. Below the levator ani muscle posterolaterally to the anal canal is situated ischioanal fossa with deep retroanal spaces and anococcygeal ligament; on anterior aspect is caudal portion of peritoneoperineal fascia with recto/ano/-prostatic ligament/muscle/. A uniform anatomical and surgical planes terminology is proposed for surgical practice Conclusions: Knowledge of the exact macro- and microstructure, topography of the perianorectal fascias and spaces, as well as harmonization of anatomical and surgical terminology is important for clinical staging of the rectal cancer local spread, decision for neoadjuvant therapy, performing of radical R0 rectal mobilization during rectal cancer operations and exact postoperative pathological staging. 355. Oncological Outcome of CT4 Rectal Cancer R.G. Orsini1, T.A. Vermeer1, R.L.H. Dudink1, A.P. Schouten van der Velden1, I.H.J.T. de Hingh1, G.A.P. Nieuwenhuijzen1, H.J.T. Rutten1 1 Catharina Hospital, Department of Surgery, Eindhoven, The Netherlands Purpose of the study: Despite improvements in the treatment for clinical T4 rectal cancer the prognosis stays poor. However studies with large patient samples are scarce. As our hospital is a national referral center for locally advanced rectal cancer we have a lot experience in this field. We studied the outcome of cT4 rectal cancer and the influence of multiple therapy strategies. Methods: Patients with cT4M0 rectal cancer who underwent TME surgery in our institution between 1995 and 2011 were selected. Clinical data were collected retrospectively including type of (neo)adjuvant therapy, type of surgery and resections, tumor characteristics, post-operative complications, disease recurrence and mortality. Prognostic factors were analyzed uni- and multivariately. Results: A total of 347 patients were selected (199 male, 148 female). Mean follow-up 37.8 months. Mean age 63.1 years. 79,5% (n¼276) received neo-adjuvant radio chemotherapy. The majority was treated with either abdominoperineal resection 53.6% (n¼186) or low anterior resection 42.1% (n¼146). 71.2% (n¼247) had no disease progression during follow up. 17.9% (n¼62) developed metastasis, 6.3% (n¼22) of the patients had a local recurrence and 4.6% (n¼16) had both distant metastasis and local recurrence. 5-year overall survival was 57.8%. 5-year cancer specific survival was 70.5%. 5-year relapse free survival was 59,1%, metastasis free survival was 70.0% and recurrence free survival was 84.5%. After multivariate analysis the prognostic factor for overall survival was age (p¼0.34). For cancer specific survival the prognostic factors were pN stadium (p¼0.003) and R0 resections (p¼0.006). The most important prognostic factors for relapse free survival were downstaging (p¼0.005) and R0 Resections 0.022). For developing distant metastasis, downstaging (p¼0.01), pN stadium (p¼0.003) and neo-adjuvant treatment (p¼0.017) are prognostic variables. R0 resection (p<0.001) is again the prognostic factor for local recurrence.
ABSTRACTS Conclusions: In our institution patients with cT4 rectal cancer have a five year cancer specific survival of 70,6% and a 5-year relapse free survival of 58%. A radical resection is still the most important prognostic factor in oncological outcome. Furthermore tumor downstaging shows to be an important factor on the outcome. The patient with a T4 rectal tumor will benefit the most from a multidisciplinary approach with neo-adjuvant treatment followed by a radical resection. 357. Prognostic Markers in Patients with Metastatic Colorectal Cancer A. Belyaeva1, A. Moiseenko1, M. Tsicoridze1, A. Karachun1, A. Gulyaev1 1 N.N. Petrov Scientific Research Institute of Oncology, Gastrointestinal Tumours, St-Petersburg, Russian Federation Background: individualization of treatment of patients with metastatic colorectal cancer should be based on evaluation of prognostic markers. Materials and methods: from January 2011 till March 2012 68 patients with colorectal cancer and synchronous metastases were included. There were 25 men and 43 women. Their middle age was 58.710.8 years. Such prognostic markers as CEA level and localization, number and size of distant metastases were analyzed. Results: 43 patients (63.2%) had distant metastases only in liver, three patients (4.4%) had double-side liver lesions and 22 patients (32.4%) had metastases in liver other organs. In patients with only liver lesions there were 16 cases with monolobe lesions (37.2%), 12 of them had right lobe lesions and 4 cases had left lobe lesions. 27 patients (62.8%) had bilobar liver lesions. Number and size of liver lesions also were analysed in patients with only liver lesions. 12 patients (27.9%) had only one lesion, 10 patients (23.3%) had two lesions and 21 patients (48.8%) had three or more liver lesions. 13 patients (27.1%) had lesion/s less than 3 cm in diameter, 20 patients (45.8%) had lesion/s from 3 to 5 cm and 13 patients (27.1%) had lesion/s more than 5 cm. Normal ranges of CEA were found in 12 from 68 analysed cases (17.6%), CEA above the line but less than 100 ng/ml was found in 35 cases (51.5%) and in 21 cases (30.9%) level of CEA was more than 100 ng/ml. Conclusions: more than a third of patients with synchronous liver metastases from colorectal origin had lesions only in one lobe. Almost a half of these patients had only one or two lesions. CEA level less than 100 ng/ ml was found in two thirds of all examined patients and also in two thirds of patients with only liver lesions. Thereby it was found that about a half of such patients could have favourable prognosis if undergo combined treatment. 358. The Young Rectal Cancer Patient R.G. Orsini1, L.N. van Steenbergen1, V.E. Lemmens1, I.H.J.T. de Hingh1, H.J.T. Rutten1 1 Catharina Hospital, Department of Surgery, Eindhoven, The Netherlands Background: Multiple studies have shown a rising incidence of rectal cancer in young patients, particularly the sporadic or non familiar forms. These young patients often present with more advanced stage of disease, different tumor characteristics (poorly differentiated), resulting in possibly worse oncological outcome. However more recent studies failed to find evidence for worse outcome when tumor stages and outcome were compared to older patients. We studied the data of younger rectal cancer patients in the Comprehensive Cancer Center South (CCCS) of the Netherlands to see if we could confirm the relative favourable outcome. Methods: The CCCS records data of all newly diagnosed cancer patients in the southern Netherlands, an area of more than 2.000.000 inhabitants. Data of rectal cancer patients diagnosed between 1989 until 2009 were reviewed. Patients older than 70 years were excluded from this analysis, because of the completely different dynamics regarding survival, ageing and the influence of comorbidities. Results: A total of 5053 patients were selected (40 years n¼ 143 and 45years n¼300). Using a cut-off point of both at 40 and 45 years the overall survival was significantly better in the younger patients compared
ABSTRACTS to older patients regarding tumor stage (both p<0,001). However, younger patients had significantly more advanced stage of disease (p¼0.020 and p¼0.0064 at cut-off points of 40 and 45 years respectively). They also received more (neo)adjuvant chemotherapy (41% vs 26%) or radiotherapy (63% vs 59%). In our population both patient groups had better survival over time, comparing the first and second decade. This effect was even more prominent in the younger age group compared to older patients (HR 0.47 (0.28-0.81) p<0,05 vs. 0.85 (0.79-0.93) p<0,05). Conditional 5-year survival-rate in younger patients was similar to older patients. Conclusions: This study shows that oncological outcome of younger patients is the same as in older patients, despite the fact that younger patients present with more aggressive tumors and higher disease state. The standard treatment for younger patients seems appropriate. We have to focus on improving awareness amongst health-care providers, this can result in more and earlier detection, rather than applying more aggressive treatment. 359. Multivisceral Resections for Locally Advanced Colorectal Cancer - is Occlusive Presentation an Indipendent Prognostic Factor? A. Rizzuto1, C. Folliero1, V. Orsini1, R. Cardona1, R. Sacco1 1 university magna graecia of catanzaro, general and visceral surgery, Catanzaro, Italy Background: Practise guidelines recommended en bloc multivisceral resection(MRV) for all involved organs in patients with locally advanced adherent colorectal cancer(LAACRC) to riduce local ricurrence and improved survival. Any clear management is indicated for LAARC in occlusive syndrome at first presentation. Aim of this study was the impact of occlusive syndrome in LAACRC n terms of survival and the eventual role like a prognostic factor. Material and methods: 43 patients underwent abdominal RMV for cancer with curative purpose;about these 22 for LAACRC Among these a group of 6 patients with occlusive was compared with a second one of 16 patients with uncomplicated presentation presentation. For every patient tumor,clinical characteristics,surgical technique, hospitalization«s time, hystologic exams were analysed . Three years was the follow-up with check every 6 months. P Statistical analysis was performed with a commerciable available software package(SPSS for windows) Continuous and discrete variables were assessed with one way analysis of variance and Test T student.P<.05 was considered statistically significant. Results: Decrease of survival in patients underwent surgery for LAARC(p¼0,033) was observed, postoperative complications rate was higher for patients with uncomplicated presentation.(p¼0,004) Higher CA19.9 values were associate to RMV with complicated presentation(p¼0,004) and connected with law survival(p¼0,024) Conclusions: Occlusive presentation is a negative prognostic factor for the execution of RMV for LAARC, Higher level of CA 19.9 are connected with survival decrease at 3 years follow up. Further research and randomized trials are requeared to validate these findings. 360. Urodynamic Findings After Colorectal Surgery A. Rizzuto1, R. Romano1, C. Folliero1, G. Lacava2, R. Sacco3 1 University Magna Graecia of Catanzaro, General and Visceral Surgery, Catanzaro, Italy 2 University Magna Graecia of Catanzaro, Urology, Catanzaro, Italy 3 University Magna Graecia of Catanzaro, General nd Visceral Surgery, Catanzaro, Italy Background: Urynary Dysfunctions occur frequently after colorectal surgery.The introduction of TME(total mesorectal excision) has reduced the complication«s rate to less than 5%. Age,pre-operative radiation therapy,abdominoperineal resection, and surgery which fails to respect the ~asacred planes’ of TME are the four major risk factors for post-operative sexual and urinary sequelae.
841 Sex,age,cardiovascular disease,diabetes are strictly connected with preoperative dysfunctions. Many patients suffering from urinary dysfunctions are undiagnosed and untreated. Aim of this study is to identify,evaluate and manage urinary dysfunctions after colorectal surgery based upon the available evidence and urodynamic findings independently of patient«s symptoms. Material and methods: For 35 patients with primary colorectal cancer and treated with radical surgery were systematically observed.Pre and post operative valuation was performed through ultrasound,uroflowmetry. Results: Ultrasound and urodynamic exam pre-operatively assessed urynary disfunctions in 8 patients;among these patients bladder outlet obstruction was found in 6 patients,detrusor ipereflexia 1 patient and in low bladder sensation in 1 patient. Urodynamic exam 12 months after surgery showed dysfunction in 14 patients(p¼0,015);4 detrusor ipereflexia(28,5%),5 vescico-uretral dyssynergia(36%), 2 neu-rogenic bladder(14,2%).Any association was found between urodynamic findings and surgycal technique. The examination provides precise evidence of diagnosis and treatment for urinary dysfunction. Conclusion: Urodynamic exam has a central role for the diagnosis and management of urynary dysfunction and hast o be performed systematically in patients undergoing colorectal surgery. Keywords: TME-Urodynamic-voiding dysfunction-colorectal surgery 361. An Immunohistochemical Study on Fetal Pelves Reveals Sensoryautonomic Pathways in Relation to Dissection Planes for Total Mesorectal Excision A.C. Kraima1, M. Derks2, H.J. Rutten3, C.J.H. Van de Velde4, M.C. DeRuiter1 1 Leiden University Medical Center, Anatomy & Embryology, Leiden, The Netherlands 2 Academical Medical Center, Gynaecology, Amsterdam, The Netherlands 3 Catherina Hospital Eindhoven, Surgery, Eindhoven, The Netherlands 4 Leiden University Medical Center, Surgery, Leiden, The Netherlands Background: Preservation of the pelvic autonomic nerves in total mesorectal excision is of crucial importance as post-operative anorectal and urogenital dysfunction are mainly caused by surgical nerve damage. Maintenance of pelvic function requires sufficient efferent and afferent pathways. Afferent fibers include those accompanying the pudendal nerve and the autonomic nerves. The latter mediate visceral sensations such as sexual excitement, vesical and rectal distension, as well as pain sensations. Surgical preservation of these pathways might specifically contribute to improved functional outcome. The aim of this study is to reveal the afferent autonomic pathways and describe their relation with peri-rectal fascia sheaths. Material and methods: Female fetal pelves, with a gestational age of 12 and 21 weeks, were studied. Paraffin embedded blocks were sliced in transverse sections of 10 mm. Analysis was performed by conventional histological staining and immunohistochemical staining with S100, a pan *neuron marker and anti-calcitonin gene related protein for sensory nerve fiber labeling. Results: The afferent autonomic pathways were located in the hypogastric nerves (HN) and the anterosuperior part of the inferior hypogastric plexus (IHP). The bulk of the sensory fibers were located inferior to the medial rectal artery at the level of the uterosacral ligament. The HN were found in the retro-rectal space posterior to the pre-hypogastric fascia. Bilateral connections of autonomic nerves were seen in the recto-vaginal and vaginal-vesical space, but no bilateral sensory autonomic connections were observed. Conclusion: Sensory-autonomic pathways run in the HN and the anterosuperior part of the IHP. They are prone to surgical damage during dissection of the uterosacral ligament and ligation of the middle rectal artery in total mesorectal excision. The correct surgical plane for posterior rectal dissection is between the peri-rectal and pre-hypogastric fascia sheaths.
ABSTRACTS Conclusions: In our institution patients with cT4 rectal cancer have a five year cancer specific survival of 70,6% and a 5-year relapse free survival of 58%. A radical resection is still the most important prognostic factor in oncological outcome. Furthermore tumor downstaging shows to be an important factor on the outcome. The patient with a T4 rectal tumor will benefit the most from a multidisciplinary approach with neo-adjuvant treatment followed by a radical resection. 357. Prognostic Markers in Patients with Metastatic Colorectal Cancer A. Belyaeva1, A. Moiseenko1, M. Tsicoridze1, A. Karachun1, A. Gulyaev1 1 N.N. Petrov Scientific Research Institute of Oncology, Gastrointestinal Tumours, St-Petersburg, Russian Federation Background: individualization of treatment of patients with metastatic colorectal cancer should be based on evaluation of prognostic markers. Materials and methods: from January 2011 till March 2012 68 patients with colorectal cancer and synchronous metastases were included. There were 25 men and 43 women. Their middle age was 58.710.8 years. Such prognostic markers as CEA level and localization, number and size of distant metastases were analyzed. Results: 43 patients (63.2%) had distant metastases only in liver, three patients (4.4%) had double-side liver lesions and 22 patients (32.4%) had metastases in liver other organs. In patients with only liver lesions there were 16 cases with monolobe lesions (37.2%), 12 of them had right lobe lesions and 4 cases had left lobe lesions. 27 patients (62.8%) had bilobar liver lesions. Number and size of liver lesions also were analysed in patients with only liver lesions. 12 patients (27.9%) had only one lesion, 10 patients (23.3%) had two lesions and 21 patients (48.8%) had three or more liver lesions. 13 patients (27.1%) had lesion/s less than 3 cm in diameter, 20 patients (45.8%) had lesion/s from 3 to 5 cm and 13 patients (27.1%) had lesion/s more than 5 cm. Normal ranges of CEA were found in 12 from 68 analysed cases (17.6%), CEA above the line but less than 100 ng/ml was found in 35 cases (51.5%) and in 21 cases (30.9%) level of CEA was more than 100 ng/ml. Conclusions: more than a third of patients with synchronous liver metastases from colorectal origin had lesions only in one lobe. Almost a half of these patients had only one or two lesions. CEA level less than 100 ng/ ml was found in two thirds of all examined patients and also in two thirds of patients with only liver lesions. Thereby it was found that about a half of such patients could have favourable prognosis if undergo combined treatment. 358. The Young Rectal Cancer Patient R.G. Orsini1, L.N. van Steenbergen1, V.E. Lemmens1, I.H.J.T. de Hingh1, H.J.T. Rutten1 1 Catharina Hospital, Department of Surgery, Eindhoven, The Netherlands Background: Multiple studies have shown a rising incidence of rectal cancer in young patients, particularly the sporadic or non familiar forms. These young patients often present with more advanced stage of disease, different tumor characteristics (poorly differentiated), resulting in possibly worse oncological outcome. However more recent studies failed to find evidence for worse outcome when tumor stages and outcome were compared to older patients. We studied the data of younger rectal cancer patients in the Comprehensive Cancer Center South (CCCS) of the Netherlands to see if we could confirm the relative favourable outcome. Methods: The CCCS records data of all newly diagnosed cancer patients in the southern Netherlands, an area of more than 2.000.000 inhabitants. Data of rectal cancer patients diagnosed between 1989 until 2009 were reviewed. Patients older than 70 years were excluded from this analysis, because of the completely different dynamics regarding survival, ageing and the influence of comorbidities. Results: A total of 5053 patients were selected (40 years n¼ 143 and 45years n¼300). Using a cut-off point of both at 40 and 45 years the overall survival was significantly better in the younger patients compared
ABSTRACTS to older patients regarding tumor stage (both p<0,001). However, younger patients had significantly more advanced stage of disease (p¼0.020 and p¼0.0064 at cut-off points of 40 and 45 years respectively). They also received more (neo)adjuvant chemotherapy (41% vs 26%) or radiotherapy (63% vs 59%). In our population both patient groups had better survival over time, comparing the first and second decade. This effect was even more prominent in the younger age group compared to older patients (HR 0.47 (0.28-0.81) p<0,05 vs. 0.85 (0.79-0.93) p<0,05). Conditional 5-year survival-rate in younger patients was similar to older patients. Conclusions: This study shows that oncological outcome of younger patients is the same as in older patients, despite the fact that younger patients present with more aggressive tumors and higher disease state. The standard treatment for younger patients seems appropriate. We have to focus on improving awareness amongst health-care providers, this can result in more and earlier detection, rather than applying more aggressive treatment. 359. Multivisceral Resections for Locally Advanced Colorectal Cancer - is Occlusive Presentation an Indipendent Prognostic Factor? A. Rizzuto1, C. Folliero1, V. Orsini1, R. Cardona1, R. Sacco1 1 university magna graecia of catanzaro, general and visceral surgery, Catanzaro, Italy Background: Practise guidelines recommended en bloc multivisceral resection(MRV) for all involved organs in patients with locally advanced adherent colorectal cancer(LAACRC) to riduce local ricurrence and improved survival. Any clear management is indicated for LAARC in occlusive syndrome at first presentation. Aim of this study was the impact of occlusive syndrome in LAACRC n terms of survival and the eventual role like a prognostic factor. Material and methods: 43 patients underwent abdominal RMV for cancer with curative purpose;about these 22 for LAACRC Among these a group of 6 patients with occlusive was compared with a second one of 16 patients with uncomplicated presentation presentation. For every patient tumor,clinical characteristics,surgical technique, hospitalization«s time, hystologic exams were analysed . Three years was the follow-up with check every 6 months. P Statistical analysis was performed with a commerciable available software package(SPSS for windows) Continuous and discrete variables were assessed with one way analysis of variance and Test T student.P<.05 was considered statistically significant. Results: Decrease of survival in patients underwent surgery for LAARC(p¼0,033) was observed, postoperative complications rate was higher for patients with uncomplicated presentation.(p¼0,004) Higher CA19.9 values were associate to RMV with complicated presentation(p¼0,004) and connected with law survival(p¼0,024) Conclusions: Occlusive presentation is a negative prognostic factor for the execution of RMV for LAARC, Higher level of CA 19.9 are connected with survival decrease at 3 years follow up. Further research and randomized trials are requeared to validate these findings. 360. Urodynamic Findings After Colorectal Surgery A. Rizzuto1, R. Romano1, C. Folliero1, G. Lacava2, R. Sacco3 1 University Magna Graecia of Catanzaro, General and Visceral Surgery, Catanzaro, Italy 2 University Magna Graecia of Catanzaro, Urology, Catanzaro, Italy 3 University Magna Graecia of Catanzaro, General nd Visceral Surgery, Catanzaro, Italy Background: Urynary Dysfunctions occur frequently after colorectal surgery.The introduction of TME(total mesorectal excision) has reduced the complication«s rate to less than 5%. Age,pre-operative radiation therapy,abdominoperineal resection, and surgery which fails to respect the ~asacred planes’ of TME are the four major risk factors for post-operative sexual and urinary sequelae.
841 Sex,age,cardiovascular disease,diabetes are strictly connected with preoperative dysfunctions. Many patients suffering from urinary dysfunctions are undiagnosed and untreated. Aim of this study is to identify,evaluate and manage urinary dysfunctions after colorectal surgery based upon the available evidence and urodynamic findings independently of patient«s symptoms. Material and methods: For 35 patients with primary colorectal cancer and treated with radical surgery were systematically observed.Pre and post operative valuation was performed through ultrasound,uroflowmetry. Results: Ultrasound and urodynamic exam pre-operatively assessed urynary disfunctions in 8 patients;among these patients bladder outlet obstruction was found in 6 patients,detrusor ipereflexia 1 patient and in low bladder sensation in 1 patient. Urodynamic exam 12 months after surgery showed dysfunction in 14 patients(p¼0,015);4 detrusor ipereflexia(28,5%),5 vescico-uretral dyssynergia(36%), 2 neu-rogenic bladder(14,2%).Any association was found between urodynamic findings and surgycal technique. The examination provides precise evidence of diagnosis and treatment for urinary dysfunction. Conclusion: Urodynamic exam has a central role for the diagnosis and management of urynary dysfunction and hast o be performed systematically in patients undergoing colorectal surgery. Keywords: TME-Urodynamic-voiding dysfunction-colorectal surgery 361. An Immunohistochemical Study on Fetal Pelves Reveals Sensoryautonomic Pathways in Relation to Dissection Planes for Total Mesorectal Excision A.C. Kraima1, M. Derks2, H.J. Rutten3, C.J.H. Van de Velde4, M.C. DeRuiter1 1 Leiden University Medical Center, Anatomy & Embryology, Leiden, The Netherlands 2 Academical Medical Center, Gynaecology, Amsterdam, The Netherlands 3 Catherina Hospital Eindhoven, Surgery, Eindhoven, The Netherlands 4 Leiden University Medical Center, Surgery, Leiden, The Netherlands Background: Preservation of the pelvic autonomic nerves in total mesorectal excision is of crucial importance as post-operative anorectal and urogenital dysfunction are mainly caused by surgical nerve damage. Maintenance of pelvic function requires sufficient efferent and afferent pathways. Afferent fibers include those accompanying the pudendal nerve and the autonomic nerves. The latter mediate visceral sensations such as sexual excitement, vesical and rectal distension, as well as pain sensations. Surgical preservation of these pathways might specifically contribute to improved functional outcome. The aim of this study is to reveal the afferent autonomic pathways and describe their relation with peri-rectal fascia sheaths. Material and methods: Female fetal pelves, with a gestational age of 12 and 21 weeks, were studied. Paraffin embedded blocks were sliced in transverse sections of 10 mm. Analysis was performed by conventional histological staining and immunohistochemical staining with S100, a pan *neuron marker and anti-calcitonin gene related protein for sensory nerve fiber labeling. Results: The afferent autonomic pathways were located in the hypogastric nerves (HN) and the anterosuperior part of the inferior hypogastric plexus (IHP). The bulk of the sensory fibers were located inferior to the medial rectal artery at the level of the uterosacral ligament. The HN were found in the retro-rectal space posterior to the pre-hypogastric fascia. Bilateral connections of autonomic nerves were seen in the recto-vaginal and vaginal-vesical space, but no bilateral sensory autonomic connections were observed. Conclusion: Sensory-autonomic pathways run in the HN and the anterosuperior part of the IHP. They are prone to surgical damage during dissection of the uterosacral ligament and ligation of the middle rectal artery in total mesorectal excision. The correct surgical plane for posterior rectal dissection is between the peri-rectal and pre-hypogastric fascia sheaths.