MRI assessment of the bony pelvis may help predict resectability of rectal cancer

Advantages of robotic surgery for rectal cancer compared to laparoscopic surgery: pelvic anatomy and its impact on urinary dysfunction

The anatomical dimensions and the shape of the pelvis influence surgical difficulty for rectal cancer. Compared to conventional laparoscopic surgery, robot-assisted surgery is expected to improve surgical outcomes due to the multi-joint movement of its surgical instruments. The aim of this study was to investigate the impact of pelvic anatomical indicators on short-term outcomes of patients with rectal cancer. A retrospective analysis was conducted using data from 129 patients with rectal cancer who underwent conventional laparoscopic low anterior resection (L-LAR) or robot-assisted low anterior resection (R-LAR) with total mesorectal excision or tumor-specific mesorectal excision between January 2014 and December 2022. The transverse diameter of the lesser pelvis and the sacral promontory angle were used as indicators of pelvic anatomy. The sacral promontory angle was not associated with age and sex while the pelvic width was smaller in male than in female. The pelvic width did not affect postoperative complications in both L-LAR and R-LAR. In contrast, postoperative urinary dysfunction occurred more frequently in patients with a small sacral promontory angle (p = 0.005) in L-LAR although there was no impact on short-term outcomes in R-LAR. Multivariate analysis demonstrated that a small sacral promontory angle was an independent predictive factor for urinary dysfunction (p = 0.032). Sharp angulation of the sacral promontory was a risk factor for UD after L-LAR. Robot-assisted surgery could overcome anatomical difficulties and reduce the incidence of UD.

Essential knowledge and technical tips for total mesorectal excision and related procedures for rectal cancer

Total mesorectal excision (TME) has greatly improved rectal cancer surgery outcomes by reducing local recurrence and enhancing patient survival. This review outlines essential knowledge and techniques for performing TME. TME emphasizes the complete resection of the mesorectum along embryologic planes to minimize recurrence. Key anatomical insights include understanding the rectal proper fascia, Denonvilliers fascia, rectosacral fascia, and the pelvic autonomic nerves. Technical tips cover a step-by-step approach to pelvic dissection, the Gate approach, and tailored excision of Denonvilliers fascia, focusing on preserving pelvic autonomic nerves and ensuring negative circumferential resection margins. In Korea, TME has led to significant improvements in local recurrence rates and survival with well-adopted multidisciplinary approaches. Surgical techniques of TME have been optimized and standardized over several decades in Korea, and minimally invasive surgery for TME has been rapidly and successfully adopted. The review emphasizes the need for continuous research on tumor biology and precise surgical techniques to further improve rectal cancer management. The ultimate goal of TME is to achieve curative resection and function preservation, thereby enhancing the patient's quality of life. Accurate TME, multidisciplinary-based neoadjuvant therapy, refined sphincter-preserving techniques, and ongoing tumor research are essential for optimal treatment outcomes.

Using CT-Based Pelvimetry and Visceral Obesity Measurements to Predict Total Mesorectal Excision Quality for Patients Undergoing Rectal Cancer Surgery

BACKGROUND

A complete total mesorectal excision is the criterion standard in curative rectal cancer surgery. Ensuring quality is challenging in a narrow pelvis, and obesity amplifies technical difficulties. Pelvimetry is the measurement of pelvic dimensions, but its role in gauging preoperatively the difficulty of proctectomy is largely unexplored.

OBJECTIVE

To determine pelvic structural factors associated with incomplete total mesorectal excision after curative proctectomy and build a predictive model for total mesorectal excision quality.

DESIGN

Retrospective cohort study.

SETTING

A quaternary referral center database of patients diagnosed with rectal adenocarcinoma (2009-2017).

PATIENTS

Curative-intent proctectomy for rectal adenocarcinoma.

INTERVENTIONS

All radiological measurements were obtained from preoperative CT images using validated imaging processing software tools. Completeness of total mesorectal excision was obtained from histology reports.

MAIN OUTCOME MEASURES

Ability of radiological pelvimetry and obesity measurements to predict total mesorectal excision quality.

RESULTS

Of the 410 cases meeting inclusion criteria, 362 underwent a complete total mesorectal excision (88%). Multivariable regression identified a deeper sacral curve (per 100 mm 2 [OR: 1.14; 95% CI, 1.06-1.23; p < 0.001]) and a greater transverse distance of the pelvic outlet (per 10 mm [OR:1.41, 95% CI, 1.08-1.84; p = 0.012]) to be independently associated with incomplete total mesorectal excision. An increased area of the pelvic inlet (per 10 cm 2 [OR: 0.85; 95% CI, 0.75-0.97; p = 0.02) was associated with a higher rate of complete mesorectal excision. No difference in visceral obesity ratio and visceral obesity (ratio >0.4 vs <0.4) between BMI (<30 vs ≥30) and sex was identified. A model was built to predict mesorectal quality using the following variables: depth of sacral curve, area of pelvic inlet, and transverse distance of the pelvic outlet.

LIMITATIONS

Retrospective analysis is not controlled for the choice of surgical approach.

CONCLUSIONS

Pelvimetry predicts total mesorectal excision quality in rectal cancer surgery and can alert surgeons preoperatively to cases of unusual difficulty. This predictive model may contribute to treatment strategy and aid in the comparison of outcomes between traditional and novel techniques of total mesorectal excision. See Video Abstract .

USO DE MEDICIONES DE PELVIMETRA Y OBESIDAD VISCERAL BASADAS EN TC PARA PREDECIR LA CALIDAD DE TME EN PACIENTES SOMETIDOS A CIRUGA DE CNCER DE RECTO

ANTECEDENTES:Una escisión mesorrectal total y completa es el estándar de oro en la cirugía curativa del cáncer de recto. Garantizar la calidad es un desafío en una pelvis estrecha y la obesidad amplifica las dificultades técnicas. La pelvimetría es la medición de las dimensiones pélvicas, pero su papel para medir la dificultad preoperatoria de la proctectomía está en gran medida inexplorado.OBJETIVO:Determinar los factores estructurales pélvicos asociados con la escisión mesorrectal total incompleta después de una proctectomía curativa y construir un modelo predictivo para la calidad de la escisión mesorrectal total.DISEÑO:Estudio de cohorte retrospectivo.ÁMBITO:Base de datos de un centro de referencia cuaternario de pacientes diagnosticados con adenocarcinoma de recto (2009-2017).PACIENTES:Proctectomía con intención curativa para adenocarcinoma de recto.INTERVENCIONES:Todas las mediciones radiológicas se obtuvieron a partir de imágenes de TC preoperatorias utilizando herramientas de software de procesamiento de imágenes validadas. La integridad de la escisión mesorrectal total se obtuvo a partir de informes histológicos.PRINCIPALES MEDIDAS DE VALORACIÓN:Capacidad de la pelvimetría radiológica y las mediciones de obesidad para predecir la calidad total de la escisión mesorrectal.RESULTADOS:De los 410 casos que cumplieron los criterios de inclusión, 362 tuvieron una escisión mesorrectal total completa (88%). Una regresión multivariable identificó una curva sacra más profunda (por 100 mm2); OR:1,14,[IC95%:1,06-1,23,p<0,001], y mayor distancia transversal de salida pélvica (por 10mm); OR:1,41, [IC 95%:1,08-1,84,p=0,012] como asociación independiente con escisión mesorrectal total incompleta. Un área aumentada de entrada pélvica (por 10 cm2); OR:0,85, [IC95%:0,75-0,97,p=0,02] se asoció con una mayor tasa de escisión mesorrectal completa. No se identificaron diferencias en la proporción de obesidad visceral y la obesidad visceral (proporción>0,4 vs.<0,4) entre el índice de masa corporal (<30 vs.>=30) o el sexo. Se construyó un modelo para predecir la calidad mesorrectal utilizando variables: profundidad de la curva sacra, área de la entrada pélvica y distancia transversal de la salida pélvica.LIMITACIONES:Análisis retrospectivo no controlado por la elección del abordaje quirúrgico.CONCLUSIONES:La pelvimetría predice la calidad de la escisión mesorrectal total en la cirugía del cáncer de recto y puede alertar a los cirujanos preoperatoriamente sobre casos de dificultad inusual. Este modelo predictivo puede contribuir a la estrategia de tratamiento y ayudar en la comparación de resultados entre técnicas tradicionales y novedosas de escisión mesorrectal total. (Traducción- Dr. Ingrid Melo).

Disparities in Outcomes following Resection of Locally Advanced Rectal Cancer

Surgical margins following rectal cancer resection impact oncologic outcomes. We examined the relationship between margin status and race, ethnicity, region of care, and facility type. Patients undergoing resection of a stage II-III locally advanced rectal cancer (LARC) between 2004 and 2018 were identified through the National Cancer Database. Inverse probability of treatment weighting (IPTW) was performed, with margin positivity rate as the outcome of interest, and race/ethnicity and region of care as the predictors of interest. In total, 58,389 patients were included. After IPTW adjustment, non-Hispanic Black (NHB) patients were 12% (p = 0.029) more likely to have margin positivity than non-Hispanic White (NHW) patients. Patients in the northeast were 9% less likely to have margin positivity compared to those in the south. In the west, NHB patients were more likely to have positive margins than NHW patients. Care in academic/research centers was associated with lower likelihood of positive margins compared to community centers. Within academic/research centers, NHB patients were more likely to have positive margins than non-Hispanic Other patients. Our results suggest that disparity in surgical management of LARC in NHB patients exists across regions of the country and facility types. Further research aimed at identifying drivers of this disparity is warranted.

Construction of a nomogram model to predict technical difficulty in performing laparoscopic sphincter-preserving radical resection for rectal cancer

BACKGROUND

Colorectal surgeons are well aware that performing surgery for rectal cancer becomes more challenging in obese patients with narrow and deep pelvic cavities. Therefore, it is essential for colorectal surgeons to have a comprehensive understanding of pelvic structure prior to surgery and anticipate potential surgical difficulties.

AIM

To evaluate predictive parameters for technical challenges encountered during laparoscopic radical sphincter-preserving surgery for rectal cancer.

METHODS

We retrospectively gathered data from 162 consecutive patients who underwent laparoscopic radical sphincter-preserving surgery for rectal cancer. Three-dimensional reconstruction of pelvic bone and soft tissue parameters was conducted using computed tomography (CT) scans. Operative difficulty was categorized as either high or low, and multivariate logistic regression analysis was employed to identify predictors of operative difficulty, ultimately creating a nomogram.

RESULTS

Out of 162 patients, 21 (13.0%) were classified in the high surgical difficulty group, while 141 (87.0%) were in the low surgical difficulty group. Multivariate logistic regression analysis showed that the surgical approach using laparoscopic intersphincteric dissection, intraoperative preventive ostomy, and the sacrococcygeal distance were independent risk factors for highly difficult laparoscopic radical sphincter-sparing surgery for rectal cancer (P < 0.05). Conversely, the anterior-posterior diameter of pelvic inlet/sacrococcygeal distance was identified as a protective factor (P < 0.05). A nomogram was subsequently constructed, demonstrating good predictive accuracy (C-index = 0.834).

CONCLUSION

The surgical approach, intraoperative preventive ostomy, the sacrococcygeal distance, and the anterior-posterior diameter of pelvic inlet/sacrococcygeal distance could help to predict the difficulty of laparoscopic radical sphincter-preserving surgery.

Interpretable machine learning model to predict surgical difficulty in laparoscopic resection for rectal cancer

Background

Laparoscopic total mesorectal excision (LaTME) is standard surgical methods for rectal cancer, and LaTME operation is a challenging procedure. This study is intended to use machine learning to develop and validate prediction models for surgical difficulty of LaTME in patients with rectal cancer and compare these models' performance.

Methods

We retrospectively collected the preoperative clinical and MRI pelvimetry parameter of rectal cancer patients who underwent laparoscopic total mesorectal resection from 2017 to 2022. The difficulty of LaTME was defined according to the scoring criteria reported by Escal. Patients were randomly divided into training group (80%) and test group (20%). We selected independent influencing features using the least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression method. Adopt synthetic minority oversampling technique (SMOTE) to alleviate the class imbalance problem. Six machine learning model were developed: light gradient boosting machine (LGBM); categorical boosting (CatBoost); extreme gradient boost (XGBoost), logistic regression (LR); random forests (RF); multilayer perceptron (MLP). The area under receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity and F1 score were used to evaluate the performance of the model. The Shapley Additive Explanations (SHAP) analysis provided interpretation for the best machine learning model. Further decision curve analysis (DCA) was used to evaluate the clinical manifestations of the model.

Results

A total of 626 patients were included. LASSO regression analysis shows that tumor height, prognostic nutrition index (PNI), pelvic inlet, pelvic outlet, sacrococcygeal distance, mesorectal fat area and angle 5 (the angle between the apex of the sacral angle and the lower edge of the pubic bone) are the predictor variables of the machine learning model. In addition, the correlation heatmap shows that there is no significant correlation between these seven variables. When predicting the difficulty of LaTME surgery, the XGBoost model performed best among the six machine learning models (AUROC=0.855). Based on the decision curve analysis (DCA) results, the XGBoost model is also superior, and feature importance analysis shows that tumor height is the most important variable among the seven factors.

Conclusions

This study developed an XGBoost model to predict the difficulty of LaTME surgery. This model can help clinicians quickly and accurately predict the difficulty of surgery and adopt individualized surgical methods.

Can 3D radiological calculations predict operational difficulties for rectal cancer?: A single center retrospective analysis

Low anterior resection, performing total mesorectal excision with appropriate pelvic dissection to prevent local recurrence, is probably the most challenging type of surgery in colorectal surgery, especially in a narrow pelvis. In this study, we aimed to predict the operation difficulty of rectal cancer by comparing the operation time with 2D and 3D pelvimetry. Sixty-six patients who underwent total mesorectal excision after neoadjuvant chemoradiotherapy due to primary rectal cancer located in the middle and lower rectum (10 cm from the anus) were included in the study. Surgery notes were reviewed and data on demographic factors, tumor stage, duration of surgery, and types of surgery were collected, as well as pelvimetric parameters. All protocols had 2D T2-weighted sequences in 3 planes (axial, sagittal, and coronal). Pelvimetric measurements were made by measuring 8 pelvic lengths and 2 angles. Pelvis and tumor volume were measured by manual margin monitoring. In each slice, both pelvis and tumor boundaries were manually drawn individually in the sagittal plane. Pelvis and tumor volumes were calculated from the set of adjacent images by summing slice thickness and products of area measurements within the pelvis and tumor boundaries. In our results, no correlation was observed with operation time, including pelvic volume. Exception for this were interacetabular distance and tumor volume. In the regression test, the only parameter that correlated with the operation time was tumor volume. In conclusion, we believe that tumor volumetric calculations may be useful in predicting difficult distal rectal carcinoma surgeries.

Creation of a Novel, Race-Adjusted, and Risk-Adapted Scoring System to Predict Positive Surgical Margins and Prolonged Operative Time During Robotic Radical Prostatectomy

Objectives: To compare racial differences and pelvis dimensions between Caucasians and African Americans (AAs) and to develop a risk calculator and scoring system to predict the risk of prolonged operative time and presence of positive surgical margins (PSM) based on these dimensions. Materials and Methods: A retrospective review of 88 consecutive patients undergoing robot-assisted laparoscopic prostatectomy with a preoperative prostate MRI conducted. Data extraction included demographic, perioperative, and postoperative oncologic outcomes. Prostate-specific antigen (PSA) was obtained within 3 months postsurgery. Wilcoxon rank sum and Fisher's exact tests were used to compare continuous and categorical data, respectively. Single and multivariable regression analysis were used to determine contribution of each factor to the composite outcomes. A risk score was created based on this analysis for predicting the composite outcome. Results: We identified 88 consecutive patients with localized prostate cancer that underwent a preoperative prostate MRI. No statistically significant differences were found with respect to age, body mass index, or any postoperative outcome. PSA was lower at diagnosis (6.49 vs 9.72, p = 0.006) and operative times were shorter in Caucasians. Rates of PSM (13 vs 14, p = 0.35), biochemical recurrence (4 vs 2, p = 0.69), and complications did not vary between the groups. Caucasians had wider/shallower pelvis dimensions. Based on these variables, we found that the log (odds of OR time >3 hours or PSM) = -5.333 + 1.158 (if AA) +0.105 × PSA +0.076 × F -0.035 × G with an area under the receiver operating characteristic curve = 0.73. Using the predefined variables, patients can be risk stratified for PSM or prolonged operative times. Conclusions: Several pelvis dimensions were found to be shorter/narrower in AAs and were associated with longer operative times. The presented risk calculator and stratification system may be used to predict prolonged operative time or having PSM.

Tumour, narrow pelvis and surgery specific factors for total mesorectal excision quality and morbidity following rectal cancer resection

BACKGROUND

Pelvic anatomy is critical in challenging rectal resections. This study investigated how pelvic anatomy relates to total mesorectal excision (TME) quality, anastomotic leakage rate, and long-term oncological outcomes.

METHODS

Patients undergoing elective rectal cancer resection from 2008 to 2017 in an Austrian institution were retrospectively reviewed regardless of the surgical approach. CT scans were analysed for pelvic measurements and volumes. The primary outcomes of interest were the correlation between pelvic dimensions and the TME quality and anastomotic leakage. Subanalysis was done by surgical approach (open, laparoscopic, transanal TME). Secondary outcomes were overall and disease-free survivals.

RESULTS

Among 154 eligible patients, 112 were included. The angle between pubic symphysis and promontory significantly correlated with worse TME grades (TME grade 1: mean(s.d.) 102.7(5.7)°; TME grade 2: 92.0(4.4)°; TME grade 3: 91.4(3.6)°; P < 0.001). A significantly lower distance between tumour and circumferential resection margin (CRM) was observed in grade 3 resections, whereas no difference appeared in grade 1 and grade 2 resection (TME grade 1: mean(s.d.) 11.92(9.4) mm; TME grade 2: 10.8(8.1) mm; TME grade 3: 3.1(4.1) mm; P = 0.003). The anastomotic leakage rate was significantly higher in case of a lower CRM (patients with anastomotic leakage: mean(s.d.) 6.8(5.8) mm versus others: 12.6(9.8) mm, P = 0.027), but not associated with pelvimetry measurements. The transanal TME (TaTME) subgroup displayed a wider angle between the pubic symphysis and promontory, younger age and improved TME quality compared to others (respectively, mean TME grades in TaTME versus open versus laparoscopic: 1.0 ± 0.0, 1.5 ± 0.7 and 1.3 ± 0.5, P = 0.013). Finally, oncological survival was not impacted by pelvic measurements or worse TME quality.

CONCLUSION

The angle between the pubic symphysis and promontory and the distance between tumour and CRM were associated with worse TME grades. The anastomotic leakage was associated with a lower CRM but not with pelvimetric measures.

Development and validation of a nomogram for predicting operating time in laparoscopic anterior resection of rectal cancer

Aims

The goal of this study is to create and verify a nomogram estimate operating time in rectal cancer (RC) patients based on clinicopathological factors and MRI/CT measurements before surgery.

Materials and Methods

The nomogram was developed in a cohort of patients who underwent laparoscopic anterior resection (L-AR) for RC. The clinicopathological and pelvis parameters were collected. Risk factors for a long operating time were determined by univariate and multivariate logistic regression analyses, and a nomogram was established with independent risk factors. The performance of the nomogram was evaluated. An independent cohort of consecutive patients served as the validation dataset.

Results

The development group recruited 159 RC patients, while 54 patients were enrolled in the validation group. Independent risk factors identified in multivariate analysis were a distance from the anal verge <5 cm (P = 0.024), the transverse diameter of the pelvic inlet (P < 0.001), mesorectal fat area (P = 0.017), and visceral fat area (P < 0.001). Then, a nomogram was built based on these four independent risk factors. The C-indexes of the nomogram in the development and validation group were 0.886 and 0.855, respectively. And values of AUC were the same with C-indexes in both groups. Besides, the calibration plots showed satisfactory consistency between actual observation and nomogram-predicted probabilities of long operating time.

Conclusions

A nomogram for predicting the risk of long operating duration in L-AR of RC was developed. And the nomogram displayed a good prediction effect and can be utilized as a tool for evaluating operating time preoperatively.

Can pelvic diameter measurement have an effect on surgical outcomes in radical cystectomy?

OBJECTIVE

To determine the effectiveness of pelvis diameters in determining postoperative outcomes in men who underwent open radical cystectomy + urinary diversion, it is aimed to predict the factors that may affect the operative difficulty and possible surgical outcomes before the operation.

METHODS

A total of 79 radical cystectomy patients operated in our institution with preoperative computed tomography (CT) were included the study. Pelvic dimensions; symphysis angle (SA), upper conjugate, lower conjugate, pelvic depth, apical depth (AD), interspinous distance (ISD), bone femoral width and soft tissue width were measured by preoperative CT. ISD index were defined as ISD/AD. Postoperative outcomes and indicators of operative difficulty were recorded. Regression analyses were used to predict perioperative and postoperative outcomes.

RESULTS

Total of 96 complications were observed in 52 of the 79 patients in ninety days (65,8%) with a mean age of 68.25 years. There were significant correlations between SA and body mass index (BMI) with operative time (p = 0.006, p < 0.001; respectively). For estimated blood loss, there were significant correlations between preoperative hematocrit (p = 0,031). Analysis of multivariate logistic regression revealed that higher Charlson comorbidity index (CCI) and BMI were found to be significant predictors for major complications while CCI, pathological T stage and ISD index are prominent predictors for surgical margin positivity.

CONCLUSIONS

Pelvic dimensions are not significant with minor or major complications. However, operative time may be associated with SA. Also, narrow and deep pelvis may increase the risk of positive surgical margins.

Advances in pelvic imaging parameters predicting surgical difficulty in rectal cancer

Due to the fixed bony structure of the pelvis, the pelvic operation space is limited, complicating the surgical operation of rectal cancer, especially middle and low rectal cancer. The closer the tumor is to the anal verge, the smaller the operative field and operating space, the longer the operative time, and the greater the incidence of intraoperative side injuries and postoperative complications. To date, there is still no clear definition of a difficult pelvis that affects the surgical operation of rectal cancer. Few related research reports exist in the literature, and views on this aspect are not the same between countries. Therefore, it is particularly important to predict the difficulty of rectal cancer surgery in a certain way before surgery and to select the surgical method most suitable for each case during the treatment of rectal cancer.

Can CT Pelvimetry Be Used to Predict Circumferential Resection Margin Positivity in Laparoscopic Resection of Middle and Lower Rectum Cancer?

Background Previous studies have shown that pelvimetry can be valuable in predicting surgical difficulties in rectal cancer operations. However, its usability in predicting circumferential resection margin (CRM) involvement remains debatable. This study investigated the factors affecting CRM status and the importance of computed tomography (CT) pelvimetry in predicting CRM involvement in laparoscopic resection of middle and lower rectal cancer. Methodology In this study, we retrospectively investigated the data of 111 patients who underwent a laparoscopic operation for middle and lower rectum cancer at Ankara University Faculty of Medicine, Department of Surgical Oncology between January 2014 and January 2020. The predictive value of CT pelvimetry and other variables on the CRM status was analyzed. Results The following four pelvic parameters differed significantly between the genders: transverse diameter of the pelvic inlet (p = 0.024), anteroposterior diameter of the pelvic outlet (p = 0.003), transverse diameter of the pelvic outlet (p < 0.001), and pelvic depth (p < 0.001). The effect of pelvic anatomic parameters on CRM involvement was not found to be significant. It was found that tumor height from the anal verge (p = 0.004), tumor size (p < 0.001), and gender (p = 0.033) were significant risk factors for CRM involvement. Survival was poor in patients with male gender (p = 0.032), perineural invasion (p < 0.001), and grade 3 tumor. Conclusions In this study, no benefit was found in predicting CRM positivity from CT pelvimetry in the laparoscopic resection of middle and lower rectal cancer. Besides, tumor height from the anal verge, tumor size, and gender were important factors for CRM positivity. Although our study sheds light on this issue, prospective randomized studies with larger sample sizes are needed.

Do bony pelvis parameters affect perioperative outcomes in open radical prostatectomy?

Objective

The present study aimed to evaluate the predictive value of bony pelvic parameters measured by computerized tomography (CT) for use in the estimation of the likely technical difficulties that may be encountered when performing open radical prostatectomy (RP) for localized prostate cancer.

Material and methods

One hundred patients, undergoing open RP for localized prostate cancer, were evaluated between October 2016 to November 2018. All operations were performed by the same experienced surgeon. Pelvic parameters were measured using spiral CT images. Data were retrospectively collected from medical, operative, radiology, and pathology records and analyzed. Positive surgical margin (PSM), presence of vesicourethral anastomosis stricture (VUAS) and urine leakage, operative time, urethral catheterization time, and estimated blood loss were used as indicators of operative difficulty. Univariate and multivariate analyses were performed to determine the significance of these variables.

Results

There was no significant correlation between the pelvic parameters of the patients and the presence of PSM, VUAS, and urine leakage. Only PSA levels and pathological tumor stage were higher in patients with PSM (p = 0.002 and p = 0.001). On univariate and multivariate analyses, none of the individual pelvic parameters assessed showed a significant relationship with the operation time, estimated blood loss, and urethral catheterization time. In univariate analysis, there was a significant relationship between PSA levels and pathological tumor stage and operation time (p = 0.048 and p = 0.001, respectively).

Conclusion

Bony pelvic parameters may not be a significant factor in influencing the perioperative outcomes of open RP. Higher PSA levels and pathological tumor stage may lead to surgical margin positivity and longer operative time.

The pelvic anatomic index is an independent predictor for the difficulty of radical prostatectomy

OBJECTIVES

The aim of the study was to investigate whether a novel simple measurement of pelvic anatomy, the pelvic anatomical index (PAI), which is obtained from simple physical examination, was predictive for potential difficulty and adverse outcome in radical prostatectomy.

MATERIALS AND METHODS

Available data from 73 consecutive radical prostatectomy patients were analyzed. The distances between umbilicus and cranial edge of the symphysis pubis (USPD) and between root of the penis and umbilicus (PUD) were measured. PAI was obtained using the formula (PUD/USPD) × body mass index (BMI). Indicators of surgical difficulty assessed were operation time (OT), dorsal vein bleeding (DVB), total blood loss (TBL), and surgical margin (SM) status. Patients with below-median values of the OT, DVB, TBL, and had negative SM were grouped as favorable surgery (n = 18).

RESULTS

Median OT, DVB, and TBL were 215 (IQR: 187.5-240) min, 380 (IQR: 200-500) cc, and 1000 (IQR: 700-1300) cc, respectively. Both PAI and BMI were significantly correlated with TBL, DVB, and OT (p < 0.05, for all). PAI and BMI significantly associated with favorable surgery (p = 0,006 and p = 0.048, respectively). However, only PAI was an independent predictor of favorable surgery in multivariable logistic regression analysis. A PAI 36 kg/m² was determined as the threshold value for favorable surgery with 83.3% sensitivity and 60% specificity.

CONCLUSION

PAI significantly correlated with almost all surgical parameters and was a significant independent predictor of favorable surgery. PAI can enable the physician to select and discuss individualized treatment options for patients during preoperative planning.

Magnetic resonance imaging pelvimetry predicts the technical difficulty of rectal surgery

BACKGROUND

The relationships between the pelvimetry and technical difficulties in performing rectal surgery for mid-low rectal cancer remain unclear.

METHODS

Two hundred and twenty-one cases of mid-low rectal cancer patients who underwent sphincter-preserved total mesorectum excision (TME) were analyzed. The data of the pelvimetry and the relative position between trocar site and tumor were measured with magnetic resonance imaging (MRI).

RESULTS

Univariate analysis showed that the interspinous diameter, the sacrococcygeal distance, and the angle of sacral promontory inclination were significantly associated with the technical difficulty during laparoscopic surgery, but only the interspinous diameter remained an independent risk factor in multivariate analysis. The simulated trocar angle θ was an independent risk factor affecting the operation time during laparoscopic surgery, simulated trocar angle η was significantly related to intraoperative blood loss in both laparoscopic surgery and transanal TME (taTME) surgery groups.

CONCLUSION

Interspinous diameter can predict difficulty in laparoscopic surgery and may provide useful information for preoperative planning and consideration of approach.

Can MRI pelvimetry predict the technical difficulty of laparoscopic rectal cancer surgery?

PURPOSE

Selection of an open or minimally invasive approach to total mesorectal excision (TME) is generally based on surgeon preference and an intuitive assessment of patient characteristics but there consensus on criteria to predict surgical difficulty. Pelvimetry has been used to predict the difficult surgical pelvis, typically using only bony landmarks. This study aimed to assess the relationship between pelvic soft tissue measurements on preoperative MRI and surgical difficulty.

METHODS

Preoperative MRIs for patients undergoing laparoscopic rectal resection in the Australasian Laparoscopic Cancer of the Rectum Trial (ALaCaRT) were retrospectively reviewed by two blinded surgeons and pelvimetric variables measured. Pelvimetric variables were analyzed for predictors of successful resection of the rectal cancer, defined by clear circumferential and distal resection margins and completeness of TME.

RESULTS

There was no association between successful surgery and any measurement of distance, area, or ratio. However, the was a strong association between the primary outcome and the estimated total pelvic volume on adjusted logistic regression analysis (OR = 0.99, P = 0.01). For each cubic centimeter increase in the pelvic volume, there was a 1% decrease in the odds of successful laparoscopic rectal cancer surgery. Intuitive prediction of unsuccessful surgery was correct in 43% of cases, and correlation between surgeons was poor (ICC = 0.18).

CONCLUSIONS

A surgeon's intuitive assessment of the difficult pelvis, based on visible MRI assessment, is not a reliable predictor of successful laparoscopic surgery. Further assessment of pelvic volume may provide an objective method of defining the difficult surgical pelvis.

A nomogram predicting the difficulty of laparoscopic surgery for rectal cancer

PURPOSE

This study aimed to identify the risk factors associated with performing a difficult laparoscopic radical resection of rectal cancer, and to establish a predictive nomogram to help individual clinical treatment decisions.

METHODS

A total of 977 patients with rectal cancer who underwent laparoscopic radical resection between January 2014 and December 2016 were enrolled in this study. The difficulty of laparoscopic-assisted rectal resection (LARR) was defined according to the scoring criteria reported by Escal. A logistic regression analysis was performed to identify the variables that may affect the difficulty of LARR, and a nomogram predicting the surgical difficulty was created.

RESULTS

A multivariate analysis demonstrated that a BMI > 28 kg/m², the distance between the tumor and the anal margin ≤ 5 cm, the maximum transverse tumor diameter > 3 cm tumor, interspinous distance < 10 cm, history of abdominal surgery, and preoperative radiotherapy were independent risk factors and they were, therefore, included in the predictive nomogram for identifying a difficult LARR.

CONCLUSIONS

This study defined a difficult LARR and identified independent risk factors for a difficult operation and created a predictive nomogram for difficult LARR. This nomogram may facilitate the stratification of patients at risk for being associated with a difficult LARR for rectal cancer.

Nomogram for predicting the feasibility of natural orifice specimen extraction after laparoscopic rectal resection

BACKGROUND AND AIM

The goal of this study was to develop a preoperative nomogram for predicting the feasibility of trans-anal natural orifice specimen extraction (NOSE) for rectal cancer.

METHODS

The analysis included 201 patients who underwent trans-anal NOSE and 457 patients who failed to undergo trans-anal NOSE in Shanghai East Hospital. The data collected included age, gender, body mass index, presence of tumor obstruction, distance from anal verge; maximum tumor diameter and anteroposterior thickness of mesorectum (AP) measured by magnetic resonance imaging; interspinous diameter, intertuberous diameter (IT), anteroposterior diameter of the inlet (API), anteroposterior diameter of the midplane, anteroposterior diameter of the outlet (APO), sacral length and pelvic depth (PD) measured by computed tomography.

RESULTS

The multivariate analysis suggested that a lower body mass index (P < 0.001), no tumor obstruction (P = 0.005), a shorter distance from anal verge (P < 0.001), a smaller tumor size (P < 0.001), a thinner AP (P < 0.001), a wider and shallower bony pelvis (API/PD, P < 0.001), and a wider and shorter pelvic outlet (IT/APO, P < 0.001) were significantly associated with an increased probability of trans-anal NOSE. Successful NOSE patients had a decreased time to liquid intake (P < 0.001), a shorter postoperative hospital stay (P < 0.001), and fewer wound infections (P = 0.045). No significant difference in the rate of mortality or recurrence was observed. The nomogram model presented an area under the receiver operating characteristic curve of 0.81 (95% CI, 0.78 to 0.85) and good calibration.

CONCLUSION

We developed a nomogram model that has some predicative value for the feasibility of laparoscopic rectal resection with trans-anal NOSE, utilizing clinical and radiologic parameters, available in most institutions.

Pelvic dimensions on preoperative imaging can identify poor-quality resections after laparoscopic low anterior resection for mid- and low rectal cancer

BACKGROUND

High-quality surgery is essential for optimal oncologic outcomes in rectal cancer, but total mesorectal excision (TME) can be difficult for mid- and low rectal cancers. Preoperative identification of patients at risk for difficult TME may change the operative approach. The objective of this study was to determine if MRI pelvimetry can predict poor-quality surgery in patients undergoing laparoscopic low anterior resection (LAR) for mid- and low rectal cancer.

METHODS

All patients undergoing laparoscopic LAR for rectal cancer ≤ 9 cm from the anal verge at a single tertiary care referral center from 2011 to 2017 were retrospectively reviewed. Pelvic dimensions were measured from preoperative staging MRI on sagittal and axial views. Pelvimetry variables were all dichotomized based on median values. Exploratory factor analysis then identified the most relevant variables for regression analysis. The primary outcome was poor-quality resection, defined as an incomplete mesorectal grade, or involved circumferential (CRM) or distal (DRM) resection margins.

RESULTS

There were 92 patients included in this study, of which 70% were male, the mean BMI was 26.0 kg/m², and the mean tumor height was 6.6 cm. Preoperative (chemo)radiotherapy was administered in 70%, and the pathologic T-stage was T3/T4 in 41%. The overall incidence of poor-quality resection was 17%, including 13% incomplete TME, 7% involved CRM, and 1% involved DRM. Factor analysis identified S1-pubic symphysis and the angle between S1 and S5-bottom of symphysis (angle ABD) as relevant variables. After adjusting for pathologic T-stage, BMI, and tumor height, a S1-S5-bottom of symphysis angle > 74.3^° (OR 6.19, 95% CI 1.18-32.37) independently predicted poor-quality resection.

CONCLUSIONS

MRI pelvimetry can identify patients at risk for a poor-quality resection after laparoscopic proctectomy for mid- and low rectal cancer. These patients may benefit from the selective use of more advanced access methods to improve surgical resection quality.

Pelvic dimension as a predictor of ureteral injury in gynecological cancer surgeries

BACKGROUND

Ureteral injury is an intractable complication in gynecological cancer surgeries. Identifying risk factors can ensure safety of the ureters intraoperatively. A narrow pelvis is known to exert extra difficulties in pelvic surgeries. However, whether pelvic dimension can affect the risk of ureteral injury in gynecological cancer surgeries is poorly understood. We aimed to evaluate the association between pelvic dimension and the risk of ureteral injury during gynecological cancer surgeries.

METHODS

All patients who had undergone gynecological cancer surgeries were searched from January 2011 to July 2017. We included patients with ureteral injury who had available data of abdominal and pelvic computed tomography for measuring pelvic dimensions. Multivariate condition logistic analysis was used to identify the risk factors independently correlated with ureteral injury in gynecological cancer surgeries.

RESULTS

A total of 43 cases with 86 controls were included in this study. We discovered that a longer anteroposterior diameter of the mid-pelvis (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.01-1.13, P = 0.019) and a shorter transverse diameter of the mid-pelvis (OR 0.92, 95% CI 0.86-0.98, P = 0.013) were associated with ureteral injury in gynecological cancer surgeries. In laparoscopic analysis, a longer anteroposterior diameter of the mid-pelvis (OR 1.11, 95% CI 1.00-1.24, P = 0.041) was a risk factor for ureteral injury. In the analysis of open surgery, a longer transverse diameter of the mid-pelvis (OR 0.79, 95% CI 0.66-0.93, P = 0.006) was a protective factor for ureteral injury.

CONCLUSIONS

This study demonstrated that mid-pelvis dimensions were associated with ureteral injury, but the observed differences were too small. In addition, pelvic inlet dimensions did not appear to relate with ureteral injury. Thus, these pelvimetry measures could not be beneficial in assessing the risk of ureteral injury in gynecological cancer surgeries.

Computed tomography based cross-sectional anatomy of the pelvis predicts surgical outcome after rectal cancer surgery

Purpose

Narrow pelvis has been considered an adverse factor for postoperative and oncologic outcomes after rectal cancer surgery. The aim of this study was to investigate the validity of using only axial CT scan images to calculate the pelvic cross-sectional area for the prediction of adverse outcomes after rectal cancer surgery.

Methods

The medical records of patients who underwent rectal cancer surgery were reviewed and analyzed retrospectively. Axial images of CT scan were used to measure the pelvic cross-sectional area. Pelvic surgical site infection (SSI), positive resection margin, and early local recurrence were adopted as end-points to analyze the impact of pelvimetry on surgical outcome.

Results

The mean pelvic cross-sectional area was 84.3 ± 10.9 cm². Males had significantly smaller pelvic areas than females (P < 0.001). Comparing pelvic cross-sectional areas according to the surgical outcomes, the results indicated that patients with pelvic SSI and local failure (positive resection margin or local recurrence within 1 year) have significantly smaller cross-sectional-area than SSI and local failure-free patients (P = 0.013 and P = 0.031). A calculated cross-sectional area of 88.8 cm² was determined as the cutoff value for the prediction of pelvic SSI and/or local failure, which was significant in a validating analysis.

Conclusion

The pelvic cross-sectional area obtained from a routine axial CT scan image was associated with pelvic SSI, positive resection margin, and early local recurrence. It might be an intuitive, feasible, and easily adoptable method for predicting surgical outcomes.

The role of MRI pelvimetry in predicting technical difficulty and outcomes of open and minimally invasive total mesorectal excision: a systematic review

BACKGROUND

The difficulty of performing total mesorectal excision (TME) for rectal cancer partly relies on the surgeon's subjective assessment of the individual patient's pelvic anatomy and tumour characteristics, which generally influences the choice of platform used (open, laparoscopic, robotic or trans-anal surgery). Recent studies have found associations between several anatomical pelvic measurements and surgical difficulty. The aim of this study was to systematically review existing data reporting the use of magnetic resonance imaging (MRI)-based pelvic measurements to predict technical difficulty and outcomes of TME, and determine whether pelvimetry could optimise patient-specific selection of a particular surgical approach.

METHODS

MEDLINE, Embase and Cochrane Library databases were systematically searched for studies reporting MRI-based pelvic measurements in patients undergoing surgery for rectal cancer, and the effect of these measurements on surgical difficulty.

RESULTS

Eleven studies reporting the association between MRI-pelvimetry measurements and rectal cancer surgical outcomes were included. Indicators for surgical difficulty used in the included studies were involved circumferential resection margin, longer operative time, incomplete TME, higher blood loss, anastomotic leak, conversion to open surgery and overall complications. Bony pelvic measurements which were associated with increased surgical difficulty in more than one study were a smaller interspinous distance, a smaller intertubercle distance, a smaller pelvic inlet and larger pubic tubercle height. Two studies identified larger mesorectal fat area as a predictor of surgical difficulty.

CONCLUSIONS

Bony pelvic measurements may predict surgical difficulty during TME, however, use of different indicators of difficulty limit comparison between studies. Early data suggest MRI soft tissue measurements may predict surgical difficulty and warrants further investigation.

Prediction of surgical difficulty in minimally invasive surgery for rectal cancer by use of MRI pelvimetry

Background

Technical difficulties in rectal surgery are often related to dissection in a limited surgical field. This study investigated the clinical value of MRI pelvimetry in the prediction of surgical difficulty associated with minimally invasive rectal surgery.

Methods

Patients with rectal cancer who underwent laparoscopic or robotic total mesorectal excision between 2005 and 2017 were reviewed retrospectively and categorized according to surgical difficulty on the basis of duration of surgery, conversion to an open procedure, use of the transanal approach, postoperative hospital stay, blood loss and postoperative complications. Preoperative clinical and MRI‐related parameters were examined to develop a prediction model to estimate the extent of surgical difficulty, and to compare anastomotic leakage rates in the low‐ and high‐grade surgical difficulty groups. Prognosis was investigated by calculating overall and relapse‐free survival, and cumulative local and distant recurrence rates.

Results

Of 121 patients analysed, 104 (86·0 per cent) were categorized into the low‐grade group and 17 (14·0 per cent) into the high‐grade group. Multivariable analysis indicated that high‐grade surgical difficulty was associated with a BMI above 25 kg/m² (odds ratio (OR) 4·45, P = 0·033), tumour size 45 mm or more (OR 5·42, P = 0·042), anorectal angle 123° or more (OR 5·98, P = 0·028) and pelvic outlet less than 82·7 mm (OR 6·62, P = 0·048). All of these features were used to devise a four‐variable scoring model to predict surgical difficulty. In patients categorized as high grade for surgical difficulty, the anastomotic leakage rate was 53 per cent (9 of 17 patients), compared with 9·6 per cent (10 of 104) in the low‐grade group (P < 0·001). The high‐grade group had a significantly higher local recurrence rate than the low‐grade group (P = 0·002).

Conclusion

This study highlights the impact of clinical variables and MRI pelvimetry in the prediction of surgical difficulty in minimally invasive rectal surgery.

Reversal of Hartmann's procedure in patients following failed colorectal or coloanal anastomosis: an analysis of 45 consecutive cases

AIM

This study aimed to assess outcomes of Hartmann's reversal (HR) after failure of previous colorectal anastomosis (CRA) or coloanal anastomosis (CAA).

METHODS

All patients planned for HR from 1997 to 2018 following the failure of previous CRA or CAA were included.

RESULTS

From 1997 to 2018, 45 HRs were planned following failed CRA or CAA performed for rectal cancer (n = 19, 42%), diverticulitis (n = 16, 36%), colon cancer (n = 4, 9%), inflammatory bowel disease (n = 2, 4%) or other aetiologies (n = 4, 9%). In two (4%) patients, HR could not be performed. HR was performed in 43/45 (96%) patients with stapled CRA (n = 24, 53%), delayed handsewn CAA with colonic pull-through (n = 11, 24%), standard handsewn CAA (n = 6, 14%) or stapled ileal pouch-anal anastomosis (n = 2, 4%). One (2%) patient died postoperatively. Overall postoperative morbidity rate was 44%, including 27% of patients with severe postoperative complication (Clavien-Dindo ≥ 3). After a mean follow-up of 38 ± 30 months (range 1-109), 35/45 (78%) patients presented without stoma. Multivariate analysis identified a remnant rectal stump < 7.5 cm in length as the only independent risk factor for long-term persistent stoma. Among stoma-free patients, low anterior resection syndrome (LARS) score was ≤ 20 (normal) in 43%, between 21 and 29 (minor LARS) in 33% and ≥ 30 (major LARS) in 24% of the patients.

CONCLUSION

HR can be recommended in patients following a failed CRA or CAA. It permits 78% of patients to be free of stoma. A short length of the remnant rectal stump is the only predictive factor of persistent stoma in these patients.

Pelvic dimensions do not impact on complications and operative difficulty in radical cystoprostatectomy and orthotopic neobladder

BACKROUND

To evaluate the factors including pelvic dimensions, which might influence operative difficulty and complications after open radical cystoprostatectomy and orthotopic neobladder reconstruction in men.

METHODS

A total of 198 RC patients operated in our institution with preoperative magnetic resonance (MRI) were analyzed were included in the study. Pelvic dimensions, including interspinous distance (ISD), bony femoral - (BFW) and soft tissue width (SW), apical prostate depth (AD), upper conjugate (UC), lower conjugate (LC) were measured by preoperative MRI. BFW, ISD, and SW indexes were defined as BFW/AD, ISD/AD, and SW/AD, respectively. Complicatons were classified according to the Clavien-Dindo classification system. As indicators of surgical difficulty; transfusion rate (TR), estimated blood loss (EBL), operative time (OT) and hospital stay (HS) were assessed. SPSS version 17.0 was used for statistical analyses.

RESULTS

A total of 239 complications developed in 143 of the 198 patients (72.2%). Correlation analysis revealed a significant indirect relationship between TR and SW/AD (P=0.023). For EBL, there were significant indirect correlations between the SW/AD, BFW/AD and ISD/AD indexes (P=0.026, P=0.05, P=0.009; respectively). Additionally, OT was directly correlated body mass index (BMI) (P=0.001); and indirectly correlated with UC, SW/AD, and BFW/AD (P=0.047, P=0.038, P=0.016, respectively). On multivariate logistic regression analyses higher American Society of Anesthesiologist (ASA) score was associated with major complications. Multivariate analyses revealed that pathological stage was a significant predictor of EBL.

CONCLUSIONS

Patients with smaller pelvises might undergo more difficult surgeries. However, it seems that small sized pelvis does not impact on operative difficulty and complication rate in radical cystoprostatectomy and orthotopic neobladder.

Assessing surgical difficulty in locally advanced mid-low rectal cancer: the accuracy of two MRI-based predictive scores

AIM

Predicting surgical difficulty is a critical factor in the management of locally advanced rectal cancer (LARC). This study evaluates the accuracy and external validity of a recently published morphometric score to predict surgical difficulty and additionally proposes a new score to identify preoperatively LARC patients with a high risk of having a difficult surgery.

METHODS

This is a retrospective study based on the European MRI and Rectal Cancer Surgery (EuMaRCS) database, including patients with mid/low LARC who were treated with neoadjuvant chemoradiation therapy and laparoscopic total mesorectal excision (L-TME) with primary anastomosis. For all patients, pretreatment and restaging MRI were available. Surgical difficulty was graded as high and low based upon a composite outcome, including operative (e.g. duration of surgery) and postoperative variables (e.g. hospital stay). Score accuracy was assessed by estimating sensitivity, specificity and area under the receiver operating characteristic curve (AROC).

RESULTS

In a total of 136 LARC patients, 17 (12.5%) were graded as high surgical difficulty. The previously published score (calculated on body mass index, intertuberous distance, mesorectal fat area, type of anastomosis) showed low predictive value (sensitivity 11.8%; specificity 92.4%; AROC 0.612). The new EuMaRCS score was developed using the following significant predictors of surgical difficulty: body mass index > 30, interspinous distance < 96.4 mm, ymrT stage ≥ T3b and male sex. It demonstrated high accuracy (AROC 0.802).

CONCLUSION

The EuMaRCS score was found to be more sensitive and specific than the previous score in predicting surgical difficulty in LARC patients who are candidates for L-TME. However, this score has yet to be externally validated.

Variation in pelvic shape and size in Eastern European males: a computed tomography comparative study

Background

The significantly accelerated development of human society in the last millennium has brought about changes in human behavior and body mass that may have influenced human bone morphology. Our objective was to analyze the variation in pelvic shape and size in males from modern and medieval populations.

Methods

We obtained 22 pelvic girdles of adult males from a medieval cemetery located in Cedynia, Poland. The control group comprised 31 contemporary male pelves from individuals inhabiting the same region. The analyzed parameters were: interspinous distance (ISD), intercristal distance (ICD), intertuberous distance (ITD), anatomic conjugate of the pelvis, height of the pelvis (HP), iliac opening angle (IOA), iliac tilt angle (ITA), and ISD/ITD/HP ratio. Geometric morphometrics was used to analyze differences in shape in the pelves. All analyses were carried out on three-dimensional CT reconstructions of pelves.

Results

ISD, ICD, and IOA were significantly greater in modern pelves than in those from Cedynia, but no significant differences were seen between the two groups in ITD, anatomical conjugate, HP, or ITA. ISD/ITD/HP ratios were significantly lower in the Cedynia group. Geometric morphometrics revealed significant differences in pelvic shape between the analyzed groups.

Discussion

The pelves of modern males are larger, wider, and flatter than those of medieval males. Changes in the set of daily activities that produce mechanical loading and estimated body mass may constitute the main factors explaining pelvic variability. However, differences in ontogenesis should also be taken into consideration, especially since growth in past populations is often found to be reduced relative to modern populations.

Anatomical basis for the choice of laparoscopic surgery for low rectal cancer through the pelvic imaging data-a cohort study

Background

Low rectal cancer surgery without anus conservation needs permanent ileostomy or colostomy which seriously affects the quality of life of patients. Therefore, low rectal cancer surgery not only pays attention to the safety of surgical treatment but also to the anus conservation.

Methods

Sixty-seven patients suffering from low rectal cancer had undergone laparoscopic surgery which was analyzed through retrospective study. They were divided into the anus-conserving and non-anus-conserving groups. Thirty-five set of pelvic data was obtained from the preoperative CT and MRI images. After that, the discriminant function was obtained to predict the surgery methods for patients with low rectal carcinoma.

Results

Anal-conserving group discriminant function (F1) = − 33.698 + 6.045 × anal margin distance (cm) + 1.105 × T4; non-anus-conserving group discriminant function (F2) = − 14.125 + 3.138 × anal margin distance (cm) + 0.804 × T4. If F1 is greater than F2, then the case can be treated as the anus reservation while if F2 is greater than F1 the case cannot be treated anus reservation. The accuracy of the discriminant function was evaluated which was found to be 97%.

Conclusion

The discriminant function of pelvic data provides anatomical basis for the choice of surgical methods for low rectal cancer.

Magnetic resonance-based pelvimetry and tumor volumetry can predict surgical difficulty and oncologic outcome in locally advanced mid-low rectal cancer

PURPOSE

To investigate the impact of the pelvic dimensions and tumor volume on surgery in locally advanced rectal cancer.

METHODS

Patients who underwent open surgery after neoadjuvant long-course chemoradiation for primary rectal cancer were included. The predictive value of magnetic resonance-based pelvic measurements and tumor volume on the surgical difficulty and oncologic outcome were analyzed.

RESULTS

125 patients were included. The independent risk factors related to the circumferential resection margin status were the pT stage [odds ratio (OR) 3.64, confidence interval (CI) 1.409-7.327] and tumor volume after neoadjuvant chemoradiotherapy (OR 1.59, CI 1.018-2.767). The operative time (p = 0.014, OR 1.453) and pelvic depth (p = 0.023, OR 1.116) were independent predictive factors for anastomotic leak. The median follow-up was 72 (2-113) months. Local recurrence was seen in 17 (14.1%) patients. Anastomotic leak (OR 1.799, CI 0.978-3.277), the circumferential resection margin status (OR 3.217, CI 1.262-7.870) and the relative tumor volume rate (OR 1.260, CI 1.004-1.912) were independent prognosticators of local recurrence. The 5-year overall survival was 66.7%. The circumferential resection margin status (hazard ratio: 4.739, CI 2.276-9.317), pN stage (OR 3.267, CI 1.195-8.930) and relative tumor volume rate (OR 2.628, CI 1.042-6.631) were independent prognostic factors for the overall survival.

CONCLUSIONS

Relative dimensions of the tumor in the pelvis influence the local recurrence and overall survival rates. Magnetic resonance-based measurements can predict the difficulty of surgery and allow surgeons to consider the appropriate surgical approach.

Predictors of surgical outcomes and survival in rectal cancer patients undergoing laparoscopic total mesorectal excision after neoadjuvant chemoradiation therapy: the interest of pelvimetry and restaging magnetic resonance imaging studies

BACKGROUND

Locally advanced rectal cancer (LARC) requires a multimodal therapy tailored to the patient and tumor characteristics. Pretreatment magnetic resonance imaging (MRI) is necessary to stage the primary tumor, while restaging MRI, which is not systematically performed, may be of interest to identify poor responders to neoadjuvant chemoradiation therapy (NCRT), and redefine therapeutic approach. The EuMaRCS study group aimed to investigate the role and accuracy of pretreatment (including pelvimetry) and restaging MRIs in predicting surgical difficulties and surgical outcomes in LARC therapy.

METHODS

Patients with mid or low LARC who were administered NCRT, who underwent laparoscopic total mesorectal excision, and for whom pretreatment and restaging MRIs were available, were included.

RESULTS

MRIs of 170 patients (median age: 61 years) were reanalyzed by the same radiologist. Pelvimetry differed significantly between males and females, but no gender difference was noted in the clinical and tumor characteristics. Tumor volume and tumor height assessed on the restaging MRI were associated, respectively, with operative time and estimated blood loss. Conversion was predicted by tumor volume, interischial distance and pubic tubercle height. The quality of the surgical resection was found to be a predictor of overall and disease-free survival. The sensitivity and specificity of tumor regression grade 1 to identify a pathologic complete response were 76.9% and 89.3%, respectively.

CONCLUSIONS

In LARC management, pelvimetry and restaging MRI may be useful to predict surgical difficulties and surgical outcomes. However, the main independent predictor of patient survival appears to be the achievement of a successful surgical resection.

MRI-based score to predict surgical difficulty in patients with rectal cancer

BACKGROUND

Rectal cancer surgery is technically challenging and depends on many factors. This study evaluated the ability of clinical and anatomical factors to predict surgical difficulty in total mesorectal excision.

METHODS

Consecutive patients who underwent total mesorectal excision for locally advanced rectal cancer in a laparoscopic, robotic or open procedure after neoadjuvant treatment, between 2005 and 2014, were included in this retrospective study. Preoperative clinical and MRI data were studied to develop a surgical difficulty grade.

RESULTS

In total, 164 patients with a median age of 61 (range 26-86) years were considered to be at low risk (143, 87·2 per cent) or high risk (21, 12·8 per cent) of surgical difficulty. In multivariable analysis, BMI at least 30 kg/m² (P = 0·021), coloanal anastomosis (versus colorectal) (P = 0·034), intertuberous distance less than 10·1 cm (P = 0·041) and mesorectal fat area exceeding 20·7 cm² (P = 0·051) were associated with greater surgical difficulty. A four-item score (ranging from 0 to 4), with each item (BMI, type of surgery, intertuberous distance and mesorectal fat area) scored 0 (absence) or 1 (presence), is proposed. Patients can be considered at high risk of a difficult or challenging operation if they have a score of 3 or more.

CONCLUSION

This simple morphometric score may assist surgical decision-making and comparative study by defining operative difficulty before surgery.

Influence of pelvic volume on surgical outcome after low anterior resection for rectal cancer

BACKGROUND

Low anterior resection (LAR) for rectal cancer is a potentially challenging operation due to limited space in the pelvis. CT pelvimetry allows to quantify pelvic space, so that its relationship with outcome after LAR may be assessed. Studies investigating this, however, yielded conflicting results. We hypothesized that a small pelvis is associated with a higher rate of incomplete mesorectal excision, anastomotic leakages, and increased rate of urinary dysfunction in patients operated for rectal cancer.

METHODS

In a single-center retrospective analysis, we studied 74 patients that underwent LAR for rectal cancer with primary anastomosis. Thin-layered multi-slice CT datasets were used for slice by slice depiction of the inner pelvic surface, and the inner pelvic volume was automatically compounded. The primary outcome was quality of total mesorectal excision (TME; Mercury grading); secondary outcomes were anastomotic leakage and urinary dysfunction with regard to pelvic dimensions. Univariate analyses and multiple logistic regression analyses were performed for the primary and the secondary outcomes.

RESULTS

Shorter obstetric conjugate diameters were associated with a higher probability of a worse TME quality (110.8 ± 10.2 vs. 105.0 ± 8.6 mm; OR 0.85; 95% CI 0.73-0.99; p = 0.038). Short interspinous distance showed a trend towards an increased risk for deteriorated TME quality (OR 0.88; 95% CI 0.76-1.0; p = 0.06). Anastomotic leakage was associated with anemia (OR 2.77; 95% CI 1.0-7.7; p = 0.047). Association between pelvic diameters or pelvic volume and anastomotic leakage or urinary dysfunction was not observed. Perioperative blood transfusions were administered more often in patients with postoperative urinary dysfunction (OR 17.67; 95% CI 2.44-127.7; p = 0.004).

CONCLUSION

Shorter obstetric conjugate diameter might be a risk factor for incompleteness of total mesorectal excision. Anastomotic leakage seems to be influenced more by clinical factors such as anemia rather than pelvic dimensions. Further studies have to prove the influence of pelvic diameter on local recurrence of rectal cancer after LAR.

Prediction of Anastomotic Leakage After Laparoscopic Low Anterior Resection in Male Rectal Cancer by Pelvic Measurement in Magnetic Resonance Imaging

OBJECTIVE

Anastomotic leakage after laparoscopic low anterior resection in male rectal cancer patients with a narrow pelvis cannot be easily resolved. The objective of this study is to assess numerical information of narrow pelvis and to determine whether prediction of morbidity can be possible.

METHODS

Retrospective medical record review was performed. From July 2007 to January 2013, 43 consecutive male patients with low rectal cancer who underwent laparoscopic low anterior resection were divided into the anastomotic leakage-negative group and anastomotic leakage-positive group. Eleven anatomic parameters were measured from preoperative magnetic resonance imaging of pelvis and a new index called "pelvic index" was calculated.

RESULTS

The pelvic index (difference between the interspinous distance and the diameter of the mesorectum divided by the depth of the cavity of the lesser pelvis) in the leakage-positive group was significantly smaller than that in the negative group (P=0.038). Comparison between those 2 groups at the border of the cut-off value of the pelvic index (13.0) showed a significant difference.

CONCLUSIONS

Preoperative assessment by the pelvic index can predict the narrow pelvis and risk of anastomotic leakage.

CT-based measurement of the inner pelvic volume

Background Surgery in the lesser pelvis is associated with a high complication rate as surgeons are spatially limited by solid anatomic structures and soft tissue borders. So far, only two-dimensional (2D) parameters have been used for risk stratification. Purpose To precisely measure the inner pelvic volume a computed tomography (CT)-based three-dimensional (3D) approach was established and compared to approximations by 2D parameter combinations. Material and Methods Thin-layered multi-slice CT datasets were used retrospectively for slice by slice depiction of the inner pelvic surface. The inner pelvic volume was then automatically compounded. Combinations of two to four 2D dimensions determined in 3D volume rendered reconstructions were correlated with the inner pelvic volume. Pearson's correlation coefficient and Chi square test were used for statistical calculations. Significance level was set at P < 0.05. Results In total 142 patients (91 men, 51 women) aged 64.8 ± 10.6 years at surgery were included in the study. Mean calculated pelvic volume was 1031.13 ± 180.06 cm³ (men, 996.57 ± 172.43 cm³; women, 1093.34 ± 178.39 cm³). Best approximations were obtained by combination of the 2D measurements transverse inlet and pelvic height for men (r = 0.799, P < 0.05) as well as transverse inlet, obstetric conjugate, interspinous distance and pelvic depth for women (r = 0.855, P < 0.05). Conclusion We describe a precise and reproducible CT-based method for pelvic volumetry. A less time consuming but still reliable approximation can be achieved by combination of two to four 2D dimensions.

CT pelvimetry and clinicopathological parameters in evaluation of the technical difficulties in performing open rectal surgery for mid-low rectal cancer

The present study aimed to evaluate the predictive value of pelvic anatomical and clinicopathological parameters for use in the estimation of the likely technical difficulties that may be encountered when performing open rectal surgery for mid-low rectal cancer. Sixty consecutive patients, undergoing open rectal surgery for mid-low rectal cancer were recruited between June 2009 and April 2014. All of the surgical procedures conducted, were low anterior resection (LAR) or abdominoperineal resection (APR). The operations were performed by the same surgeon and surgical team. Pelvic dimensions and angles were measured using three-dimensional reconstruction of spiral computerized tomography (CT) images. Operative time and intraoperative blood loss were used as indicators of operative difficulty. The independent variables were pelvic anatomical and clinicopathological parameters, and the dependent variables were operative time and intraoperative blood loss. Univariate and multivariate analyses were performed in order to determine the predictive significance of these variables. The pelvis width was significantly wider in females than in males (P<0.05), while the sacrococcygeal bending degree was significantly greater in males than in females (P<0.05). No significant difference were detected between the pelvis depth of females and males (P>0.05). Multivariate analyses showed that body mass index (BMI), tumor height, lymph node metastasis, anteroposterior diameter of the pelvic inlet, anteroposterior diameter of the pelvic outlet, height of the pubic symphysis, the sacrococcygeal distance, sacrococcygeal-pubic angle and diameter of the upper pubis to the coccyx were the main factors affecting the operative time (all P<0.05), while the maximum diameter of the tumor was the primary factor affecting intraoperative blood loss (P<0.05). Between the two procedures, the clinicopathological parameters appeared to be more valuable for predicting difficulty in LAR, in which operative time was associated with tumor height and tumor staging (R_C²=0.312; P<0.001). By contrast, the pelvic anatomical parameters appeared to be more valuable predictors of variation in APR, in which intraoperative blood loss was associated with the anteroposterior diameter of the mid-pelvis, the anteroposterior diameter of the pelvic outlet, the interspinous diameter, the depth of the sacral curvature and the sacropubic distance (R_C²=0.608; P=0.002). BMI, tumor height and the maximum diameter of the tumor may be used to predict the operative difficulty in performing open rectal surgery for mid-low rectal cancer. In addition to the associated clinicopathological parameters, wider, shallower and less curved pelvises may make the greatest contribution to reducing operative time and intraoperative blood loss. Operative difficulty is likely to be increased in deeper and narrower pelvises, or in those with greater sacrococcygeal curvature.

CT/MRI pelvimetry as a useful tool when selecting patients with rectal cancer for transanal total mesorectal excision

BACKGROUND

The quality of a total mesorectal excision (TME) is one of the most important prognostic factors for local recurrence of rectal carcinoma. The aim of this study was to clarify the manner in which lesser pelvis dimensions affect the quality of TME via the transabdominal approach, while simultaneously defining the criteria for selecting patients most likely to have Grade 3 TME outcomes for a transanal approach using the TaTME technique.

METHODS

An analysis from the registry was conducted using 93 of total 198 patients with rectal cancer of the mid- and lower third of the rectum who underwent: (1) a low anterior resection, (2) an ultra-low resection with coloanal anastomosis, or (3) an intersphincteric rectal resection, all with total mesorectal excision. The procedures were carried out at the Department of Surgery at the University Hospital Hradec Králové between 2011 and 2014. Rectal specimens were histopathologically examined according to a standardized protocol. Pelvimetry data were obtained using anteroposterior, transverse, and sagittal CT or MRI scans.

RESULTS

A correlation was found between the quality of the TME and pelvimetry parameter A5, i.e., the angle between the longitudinal axis of the symphysis, and the lines between the symphysis and the promontory (R(2) = -0.327, p < 0.001). The ordinal regression method was used to identify parameters of the model describing levels of probability for TME quality. These relationships were described by equations that provide probability of the achievement of each grade of TME.

CONCLUSION

The correlation described by obtained equations between pelvimetry parameters and the quality of TME represents a new tool for use in preoperative decision-making with regard to resection via the transanal approach (TaTME).

The new approach to the rectal cancer: 'down-to-up' double endolaparoscopic pelvic access. Preliminary evaluation of outcomes

Laparoscopic access in low anterior rectal resection is widely adopted, performing an 'up-to-down' dissection. The aim of this study is to present and analyze the outcomes of a novel surgical 'down-to-up' total mesorectal excision technique that could obviate to the well-known issues of the standard treatment. 18 suitable patients underwent double endolaparoscopic pelvic access (DEPA) 'down-to-up' technique. DEPA TME was completed in all patients, with intact mesorectum. Mean operative time was 365 min (range 280-510 min). The morbidity rate was 22%, including three radiologically detected leakage (grade A) and one pelvic abscess, requiring only a conservative management. Mortality rate at 30 and 90 days was 0%. Resection margins were negative in all patients. A median of 11 nodes (range 5-19) was retrieved per specimen. Mean length of hospital stay was 9 days (range 7-19 days). Patients were followed for an average of 14 months (range 0-42 months), with no recurrence. Despite exiguous patient's sample in this pilot study, transanal endoscopic TME with laparoscopic assistance seems to be feasible and safe, and is a promising alternative to open and laparoscopic TME. However, a conspicuous functional and oncologic long-term evaluation is required, before the widespread adoption could be recommended.

Impact of pelvic biometric measurements, visceral and subcutaneous adipose tissue areas on trifecta outcome and surgical margin status after open radical retropubic prostatectomy

OBJECTIVE

There is no sufficient evidence to demonstrate whether more challenging pelvic anatomy affects the functional and oncological outcomes of radical retropubic prostatectomy (RP). The aim of this study was to investigate the impact of pelvic biometric measurements, visceral and subcutaneous adipose tissue areas on trifecta outcome (cancer control, continence and potency) and surgical margin status after open RP.

MATERIALS AND METHODS

A retrospective study was performed on 270 patients who were diagnosed with clinically localized prostate cancer between 2005 and 2011 and underwent computed tomography imaging before RP. Pelvic bony and soft-tissue measurements, and visceral and subcutaneous adipose tissue area calculations were performed. Patients were evaluated for trifecta outcome and surgical margin status on univariate and multivariate analyses. Subgroup analysis was performed for prostate volume, body mass index (BMI) and D'Amico risk classification.

RESULTS

Univariate analysis revealed that patients with trifecta were younger, and had lower prostate-specific antigen (PSA) levels, wider symphysis angle, and narrower prostate width and soft-tissue width (p < 0.05). Patients with positive surgical margins were older, and had higher PSA levels, lower prostate volume and narrower prostate width (p < 0.05). Visceral adipose tissue area was lower in patients with trifecta when BMI was below 25 kg/cm² (p < 0.05). In multivariate analysis, PSA level and symphysis angle were statistically significant for trifecta while PSA level was the only statistically significant variable for positive surgical margins (p < 0.05). Interfemoral index was significant in the low-risk group of D'Amico classification for trifecta outcome.

CONCLUSION

Pelvic biometric measurements and adipose tissue area calculations may help in preoperative planning and the management of RP.

Robotic surgery for rectal cancer can overcome difficulties associated with pelvic anatomy

INTRODUCTION

Total mesorectal excision (TME) for rectal cancer can be challenging to perform in the presence of difficult pelvic anatomy. In our previous studies based on open and laparoscopic TME, we found that pelvic MRI-based pelvimetry could well reflect anatomical difficulty of the pelvis and operative time increased in direct proportion to the difficulty. We explored different outcomes of robotic surgery for TME based on classifications of difficult pelvic anatomies to determine whether this method can overcome these challenges.

METHODS

We reviewed data from 182 patients who underwent robotic surgery for rectal cancer between January 2008 and August 2010. Patient demographics, pathologic outcomes, pelvimetric results, and operative and postoperative outcomes were assessed. The data were compared between easy, moderate, and difficult groups classified by MRI-based pelvimetry.

RESULTS

Comparing the three groups, there was no difference between the groups in terms of operative and pathologic outcomes, including operation time. High BMI, history of preoperative chemoradiotherapy, and lower tumor levels were significantly associated with longer operation time (p < 0.001, p < 0.001, p = 0.009), but the pelvimetric parameter was not.

CONCLUSION

There was no difference between the easy, moderate, and difficult groups in terms of surgical outcomes, such as operation time, for robotic rectal surgery. The robot system can provide more comfort during surgery for the surgeon, and may overcome challenges associated with difficult pelvic anatomy.

Feasibility of single-port laparoscopic surgery for sigmoid colon and rectal cancers and preoperative assessment of operative difficulty

PURPOSE

Single-port laparoscopic surgery is more difficult for sigmoid colon and rectal cancers than for right-sided colon cancer. We sought to analyze the feasibility of this procedure for sigmoid colon and rectal cancers and to estimate its difficulty.

METHODS

We analyzed prospectively collected data from 63 consecutive patients with sigmoid colon or rectal cancers who underwent single-port laparoscopic surgery at our institution from June 2009 to December 2011. Patient and tumor characteristics, including patients' pelvic anatomy which was assessed on CT scan imaging, were evaluated to elucidate what factors would affect the difficulty of the procedure and the necessity of using an additional trocar.

RESULTS

Overall, the median operative duration was 190 min and blood loss was 20 ml, with no postoperative complications. The median number of lymph nodes harvested was 17 and the distal margin was 58 mm. The tumor was located significantly closer to the anus in cases in which an additional trocar was required in the right lower quadrant (9.5 vs 18 cm, p < 0.0001). Procedural difficulty was significantly increased in cases in which the sacral promontory protruded ventrally (odds ratio 0.779 [95% confidence interval 0.613 to 0.945], p = 0.0236).

CONCLUSIONS

Depending on tumor location and sacral promontory shape, the introduction of an additional trocar might render single-port laparoscopic surgery feasible for sigmoid colon and rectal cancer resection.

Analysis of the Anatomical Characteristics of the Pelvis in Koreans to Aid in Development of a NOTES Platform

Transanal endoscopic microsurgery (TEM) is a minimally invasive technique affording full-thickness resection of rectal tumors and can also be used as a platform for transrectal access to the peritoneal cavity for NOTES (natural orifice transluminal endoscopic surgery) procedures. The authors investigated the anatomical characteristics of the pelvis in Koreans to develop an ergonomically designed NOTES platform. A total of 256 patients (156 men and 100 women) who underwent pelvic magnetic resonance imaging for evaluating rectal neoplasms were enrolled for analysis. The authors retrospectively reviewed and calculated anatomical lengths and angles on pelvic magnetic resonance images and analyzed differences in pelvic anatomy in terms of patient gender, age, and body mass index. Various angulations were noted from the anal canal to the sacral promontory, attributable to the shape of the sacral bone. Minimal difference in pelvic anatomy was evident between men and women. In conclusions, the authors expect that their data will be useful in the development of ergonomic TEM-NOTES platforms.

The Importance of the Pathologist's Role in Assessment of the Quality of the Mesorectum

Total mesorectal excision (TME) is considered standard of care for rectal cancer treatment. Failure to remove the mesorectal fat envelope entirely may explain part of observed local and distant recurrences. Several studies suggest quality of the mesorectum after TME surgery as determined by pathological evaluation may influence prognosis. We aimed to determine the prognostic value of the plane of surgery as well as factors influencing the likelihood of a high-quality specimen by reviewing the literature. A pooled meta-analysis of relevant outcome data was performed where appropriate. A muscularis propria resection plane was found to increase the risk of local recurrence (RR 2.72 [95 % CI 1.36 to 5.44]) and overall recurrence (RR 2.00 [95 % CI 1.17 to 3.42]) compared to an (intra)mesorectal plane. Plane of surgery is an important factor in rectal cancer treatment and the documentation by pathologists is essential for the improvement of TME quality and patient outcome.