| BackgroundColorectal cancer is a frequent malignancy in the digestive tract at present.According to the latest global cancer statistics,the overall incidence rate of colorectal cancer is the third largest in the world,and it is also the second most common cause of death from malignant tumors.According to the latest cancer statistics released by the Chinese National Cancer Center,colorectal cancer incidence rates in China has now jumped to the second place in malignant tumors,the mortality rate has been ranked the fourth,and both the incidence and mortality rates of colorectal cancer in China have been rising steadily.Compared with European and American countries,the incidence of rectal cancer is higher than that of colon cancer,and 60%～70%of rectal cancer located at the mid and low rectum in China,and the proportion of advanced-stage and younger patients is relatively high.Although the treatment of rectal cancer is constantly improving,the treatment effect is still not very satisfactory.Because of its deep location in the pelvis and the close anatomical relationship with the surrounding tissues and organs,the curative operation for middle-low rectal cancer is relatively difficult to perform.Especially for some male,obese patients with a narrow pelvic space structure and lower rectal cancer(the lower edge of the tumor from the anal margin is under 5cm),it is difficult to perform a anal preservation operation.Therefore,the key to the success of the operation is to choose the appropriate surgical procedure and protect the pelvic autonomic nerve from injury.The application of laparoscopic technique in colorectal surgery is extensive due to its advantages of small abdominal interference,small trauma,light pain,rapid recovery of gastrointestinal function after surgery,short hospital stay,small and beautiful wound.With the continuous development of laparoscopic technology,studies have shown that laparoscopic total mesorectal excision(TME)had achieved the same effect as open operation for low and ultra-low rectal cancer in recent years,which is safe and feasible.Compared with open surgery,it has comparative advantages with respect to blood loss,length of hospitalization,rate of sphincter preservation and postoperative recovery.However,the difficulty of its specific operation is also affected by many factors,such as the patient’s own situation,including the patient’s sex,body mass index(BMI),visceral fat area(VFA),mesorectal fat area(MFA)and the specific condition of the tumor(including the size,location,distance from the anal edge,stage,adhesion with surrounding tissues and organs,etc.),the spatial structure of the patient’s pelvis,and the surgeon’s experience.Among these factors,the spatial structure of the patient’s pelvis has a significant impact on the surgical procedure.Some studies have found that the size and shape of the pelvis is also one of the most important factors affecting the difficulty of laparoscopic surgery.The narrow bony pelvis leads to small operation space.Besides,as the tumor is close to the anus,and it is adjacent to the surrounding bladder,prostate,and seminal vesicles(or women’s ovaries,uterus,and vagina).Surgical treatment usually involves the preservation of anus and anal function,and it is necessary to avoid damaging adjacent organs.Therefore,it is obvious that the operator’s vision will be greatly restricted and the difficulty of operation will be increased in the narrow and deep pelvic cavity during the operation,and also the therapeutic effect and prognosis will be affected.There are also related studies show that VFA is closely related to the operative time and intraoperative blood loss of laparoscopic TME for rectal cancer.Compared with BMI,it can better reflect the impact of obesity on the difficulty of surgery.Some scholars believe that MFA can be used as a predictor of the technical difficulty of TME for rectal cancer,because the larger fat area of mesorectum causes the space between pelvic fascia and visceral fascia wrapping around the mesorectum to become narrower,In this case,it will take more time to obtain a suitable surgical field during the pelvic surgery of rectal cancer.Therefore,it is very necessary for colorectal surgeons to understand thoroughly the overall structure of the pelvis before operation,and predict the difficulty of surgery in advance through the measurement of the pelvic anatomical diameters,angles,ratios,and soft tissue parameters such as VFA and MFA,and formulate appropriate and accurate surgical treatment plans.However,there is no international consensus on which pelvic diameter,angle and anatomical factors of soft tissue affect the procedure of laparoscopic radical rectal cancer resection at present,and the majority of literature reports that mentioned the pelvic parameters and soft tissue parameters are relatively few.Therefore,it is necessary to conduct a in-depth research and discussion.Part Ⅰ Measurement of differences in pelvic parameters between the sexes and the impact of obesity-related indicators on the short-term outcomes of rectal cancer patients after laparoscopic surgeryObjectiveThe present study aimed to reconstruct three-dimensional(3D)medical images of the pelvis based on thin computerized tomography(CT)for individuals with rectal cancer,measure the pelvic bone and soft tissue parameters among individuals,and explore the differences of the pelvic bone and soft tissue parameters between the sexes,and the impact of obesity-related indicators on the short-term outcomes of rectal cancer patients after laparoscopic surgery.So as to provide clinical practice and theoretical basis for surgeons to identify potentially"difficult pelvic" surgery for rectal cancer before operation.MethodsClinical,pathological and imaging data of 218 cases of rectal cancer patients undergoing laparoscopic radical resection between February 2013 and June 2022 in Wenzhou Central Hospital were retrospectively collected,including 139 males and 79 females.All of the surgical procedures conducted,were laparoscopic radical resection of rectal cancer.Based on 64-slice spiral CT scanning techniques of pelvis,a series of pelvic bone and soft tissue parameters of rectal cancer patients were measured using three-dimensional reconstruction software.These pelvic bone and soft tissue parameters included anteroposterior diameter of the pelvic inlet,transverse diameter of the pelvic inlet,anteroposterior diameter of the mid-pelvis,anteroposterior diameter of the pelvic outlet,interspinous diameter,intertuberous diameter,height of the pubic symphysis,sacrococcygeal distance,sacral distance,depth of the sacrococcygeal curvature,depth of the sacral curvature,diameter of the upper pubis to the coccyx,sacropubic distance,sacrococcygeal-pubic angle,sacropubic angle,rectal area,mesorectal fat area(MFA),visceral fat area(VFA),subcutaneous fat area(SFA),waist circumference(WC),anteroposterior abdominal diameter(APAD)and transverse abdominal diameter(TAD).According to BMI value,patients were classified as non-obese group(BMI<24kg/m~2),overweight group(24≤BMI<28kg/m~2)and obese group(BMI≥28kg/m~2);According to WC value,patients were divided into non-abdominal obesity group(male<90cm,female<85cm)and abdominal obesity group(male≥90cm,female≥85cm).The age,sex composition,operative method,postoperative pathological staging,number of lymph nodes cleaned,operative time,intraoperative blood loss,postoperative complications Clavien-Dindo(CD)grade and postoperative hospitalization days of patients in each group were compared.ResultsThe pelvic bone and soft tissue parameters of 20 patients were measured repeatedly at two different periods of time intervals,and the results of the two measures were highly correlated(P<0.05).This study showed that there were significant differences between male and female in 14 pelvic bone parameters and 3 soft tissue parameters,including anteroposterior diameter of the pelvic inlet,transverse diameter of the pelvic inlet,anteroposterior diameter of the mid-pelvis,anteroposterior diameter of the pelvic outlet,interspinous diameter,intertuberous diameter,height of the pubic symphysis,sacrococcygeal distance,sacral distance,depth of the sacrococcygeal curvature,sacropubic distance,sacrococcygeal-pubic angle,sacropubic angle,anteroposterior diameter of the pelvic inlet/sacrococcygeal distance,MFA,SFA,and APAD(all P<0.05).There were no significant differences in the other 2 pelvic bone parameters and 4 soft tissue parameters between male and female,which were depth of the sacral curvature,diameter of the upper pubis to the coccyx,rectal area,VFA,WC and TAD(all P>0.05).There were no significant differences in gender,age,operative method,postoperative pathological staging,number of lymph nodes cleaned,operative time,intraoperative blood loss,postoperative complications(CD grade),and postoperative hospitalization days among the three groups of patients:non-obese group,overweight group and obese group(all P>0.05).There were statistical differences in gender(P=0.0171)and operative methods(P=0.0016)between the two groups of non-abdominal obesity and abdominal obesity,while there were no significant differences in age,postoperative pathological staging,number of lymph nodes cleaned,operative time,intraoperative blood loss,postoperative complications(CD grade),and postoperative hospital stay between the two groups(all P>0.05).ConclusionsThe comparison of two repeated measurements verified the reliability and accuracy of the pelvis measurement method based on 3-D CT data reconstruction.There were significant differences in pelvic bone and soft tissue parameters between male and female.The female pelvis is significantly wider,shallower,and less curved than the male pelvis.While the male pelvis is significantly narrower,deeper,and more curved than the female pelvis.The sacrum of male is more straight.The mesorectum in males is thicker than that in females,and the APAD in males is significantly larger than that in females,while the SFA in males is significantly less than that in females.BMI and WC can not effectively reflect the impact of obesity on the short-terms outcome of rectal cancer patients after laparoscopic surgery.Part Ⅱ Construction of a nomogram model based on three-dimensional reconstruction and measurement of pelvic CT scans predict the technical difficulties in performing laparoscopic sphincter-preserving radical resection for rectal cancerObjectiveThe present study aimed to evaluate the predictive value of a series of pelvic bone,soft tissue and clinicopathological parameters,particularly the pelvic bone parameter,for use in the estimation of the likely technical difficulties that may be encountered when performing laparoscopic radical sphincter preserving surgery for rectal cancer.And based on this,a nomograph model for predicting the difficulty of surgery is constructed,which is more convenient for surgeons to conduct preoperative individualized evaluation for patients.MethodsClinical,pathological and radiographic data of one hundred and sixty-two consecutive patients with rectal cancer undergoing laparoscopic radical sphincter preserving surgery between February 2013 and June 2022 in Wenzhou Central Hospital were retrospectively collected,including 105 males and 57 females.All of the surgical procedures conducted,were laparoscopic anterior resection(L-AR),laparoscopic low anterior resection(L-LAR),laparoscopic ultra-low anterior resection with intersphincteric dissection(L-ISR).Both L-AR and L-LAR were performed with double-stapling technique(DST)anastomosis.There were 20 cases of L-AR,135 cases of L-LAR and 7 cases of L-ISR.Based on the thin slice CT scanning techniques of pelvis,three-dimensional reconstruction was performed,and a series of pelvic bone and soft tissue parameters of rectal cancer patients were measured using three-dimensional reconstruction software.Operative difficulty was categorized into two types:high and low surgical difficulty groups.The comprehensive evaluation of operative difficulty was based on six indicators:operative time,intraoperative blood loss,whether to use transanal incision during operation,whether to convert to laparotomy,postoperative complications,and postoperative hospital stay.Multivariate logistic regression analysis was used to observe the effect of clinicopathological,pelvic bone and soft tissue parameters on the difficulty of laparoscopic radical sphincter preserving surgery for rectal cancer,so as to screen out the indicators that can be used to predict the operative difficulty,and draw a nomogram and conduct internal verification.ResultsOf the 162 patients,21(13.0%)were classified as high surgical difficulty group,and 141(87.0%)were classified as low surgical difficulty group.Univariate analysis demonstrated that the tumor height(P=0.0024),surgical method(P<0.001),use of intraoperative preventive stoma(P<0.001),the sacrococcygeal distance(P=0.0378),anteroposterior diameter of the pelvic inlet/sacrococcygeal distance(P=0.0165),and the sacrococcygeal-pubic angle(P=0.0116)were significantly related to the highly difficult laparoscopic radical sphincter preserving surgery for rectal cancer.The results of multivariate logistic regression analysis showed that the surgical method,use of intraoperative preventive stoma,and the sacrococcygeal distance were independent risk factors for the highly difficult laparoscopic radical sphincter preserving surgery for rectal cancer(P<0.05),while the anteroposterior diameter of the pelvic inlet/sacrococcygeal distance was protective factor(P<0.05).Then the nomogram was constructed(C-index=0.824).ConclusionsThe surgical method,use of intraoperative preventive stoma,the sacrococcygeal distance,and the anteroposterior diameter of the pelvic inlet/sacrococcygeal distance can be used to predict the difficulty of laparoscopic radical sphincter preserving surgery for rectal cancer before operation,and this prediction model can help surgeons choose the appropriate operative method before operation.The prediction model also provides a certain reference value for young beginners to select appropriate rectal cancer patients before surgery and shorten the learning curve of laparoscopic rectal cancer surgery.The nomogram drawn in this study can be visualized,which is more convenient for surgeons to carry out individualized preoperative evaluation of patients,and easier for patients and family members to understand surgical risks.Part Ⅲ Clinical application research of a nomogram model based on three-dimensional reconstruction and measurement of pelvic CT scans predict the technical difficulties in performing laparoscopic assisted transanal total mesorectal excision(TaTME)for rectal cancerObjectiveThe present study aimed to screen out the cases of rectal cancer that may be highly difficult to operate through the abdomen by using the nomograph model to predict the difficulty of laparoscopic radical sphincter preserving surgery for rectal cancer,carried out laparoscopic assisted transanal total mesorectal excision(L-TaTME)for these cases,and explore the perioperative outcome and oncological results of L-TaTME.Methods51 consecutive patients,undergoing L-TaTME for mid-low rectal cancer were admitted to Nanchong Central Hospital between January 2018 and September 2022.The patients met the predictive probability criterion of highly difficult surgery according to the nomograph model for predict the difficulty of laparoscopic radical sphincter preserving surgery for rectal cancer.All patients had complete clinical pathological and radiographic data.The patients were comprised of 33 males and 18 females with a median age of 67 years(range 41～85 years).At the same time,21 consecutive patients,undergoing L-TME for rectal cancer were admitted to Wenzhou Central Hospital,who met the criterion of highly difficult laparoscopic assisted total mesorectal excision(L-TME)for a comparative study.Among 21 patients,17 were male and 4 were female with a median age of 65 years old(range,43～80years).The general baseline data,perioperative indicators and postoperative pathological indicators of the two groups were compared.ResultsThere were no significant differences in baseline data between the two groups in gender,age,body mass index(BMI),a previous history of basic diseases,ASA grade and maximum tumor diameter(all P>0.05).and there were significant differences in tumor height and neoadjuvant therapy between the two groups(both P<0.05).There were statistically significant differences in pelvic parameters between the two groups in sacrococcygeal distance and the ratio of anteroposterior diameter of the pelvic inlet to sacrococcygeal distance(all P<0.05),but there was no statistically significant difference in anteroposterior diameter of the pelvic inlet(all P>0.05).The operative time and hospitalization days after operation in L-TaTME group were shorter than those in L-TME group,and the intraoperative bleeding volume and 30-day postoperative complication rate were lower than those in L-TME group in the comparison of perioperative indicators between the two groups,the differences were statistically significant(P<0.05).However,there were no significant differences in the operation mode,whether intraoperative preventive stoma,rectal anastomosis mode,and whether conversion to open surgery(all P>0.05).There were no statistically significant differences in the comparison of postoperative pathological indicators between the two groups in terms of pathological T stage,N stage,TNM stage,whether high-quality mesorectum resection,and harvested lymph nodes(all P>0.05).ConclusionsL-TaTME is a safe and feasible treatment method in laparoscopic radical sphincter preserving surgery for rectal cancer,with good short-term effect,and can be used as a good complementary technology when technical difficulties that may be encountered in performing the traditional transabdominal L-TME. |
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