Current and future role of three-dimensional modelling technology in rectal cancer surgery: A systematic review

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.

Navigation-Assisted Surgery for Locally Advanced Primary and Recurrent Rectal Cancer

BACKGROUND

In some surgical disciplines, navigation-assisted surgery has become standard of care, but in rectal cancer, indications for navigation and the utility of different technologies remain undetermined.

METHODS

The NAVI-LARRC prospective study (NCT04512937; IDEAL Stage 2a) evaluated feasibility of navigation in patients with locally advanced primary (LARC) and recurrent rectal cancer (LRRC). Included patients had advanced tumours with high risk of incomplete (R1/R2) resection, and navigation was considered likely to improve the probability of complete resection (R0). Tumours were classified according to pelvic compartmental involvement, as suggested by the Royal Marsden group. The BrainlabTM navigation platform was used for preoperative segmentation of tumour and pelvic anatomy, and for intraoperative navigation with optical tracking. R0 resection rates, surgeons' experiences, and adherence to the preoperative resection plan were assessed.

RESULTS

Seventeen patients with tumours involving the posterior/lateral compartments underwent navigation-assisted procedures. Fifteen patients required abdominosacral resection, and 3 had resection of the sciatic nerve. R0 resection was obtained in 6/8 (75%) LARC and 6/9 (69%) LRRC cases. Preoperative segmentation was time-consuming (median 3.5 h), but intraoperative navigation was accurate. Surgeons reported navigation to be feasible, and adherence to the resection plan was satisfactory.

CONCLUSIONS

Navigation-assisted surgery using optical tracking was feasible. The preoperative planning was time-consuming, but intraoperative navigation was accurate and resulted in acceptable R0 resection rates. Selected patients are likely to benefit from navigation-assisted surgery.

Application of a three-dimensional printed pelvic model in laparoscopic radical resection of rectal cancer

Introduction

To investigate the application value of a three-dimensional (3D) printed pelvic model in laparoscopic radical resection of rectal cancer.

Methods

Clinical data of patients undergoing laparoscopic radical rectal cancer surgery in The Second People's Hospital of Lianyungang City from May 2020 to April 2022 were selected. Patients were randomly divided into general imaging examination group (control group, n=25) and 3D printing group (observation group, n=25) by random number table method, and the perioperative situation of patients in the two groups was compared.

Results

There was no significant difference in general data between the two groups (p>0.05). Operation time, intraoperative blood loss, intraoperative time to locate inferior mesenteric artery, intraoperative time to locate left colic artery, first postoperative exhaust time and length of hospital stay in the observation group were all lower than those in the control group (P < 0.05); There were no significant differences in the total number of lymph nodes and complications between the two groups (P > 0.05).

Discussion

The application of 3D printed pelvic model in laparoscopic radical resection of rectal cancer is conducive to understanding pelvic structure and mesenteric vascular anatomy, reducing intraoperative bleeding and shortening operation time, which is worthy of further clinical application.

A systematic review of the application of 3D-printed models to colorectal surgical training

BACKGROUND

The aim of this review was to explore the role of three-dimensional (3D) printing in colorectal surgical education and procedural simulation, and to assess the effectiveness of 3D-printed models in anatomic and operative education in colorectal surgery.

METHODS

A systematic review of the literature was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify relevant publications relating to the use of 3D-printed models in colorectal surgery in an educational context. The search encompassed OVID Medline, Web of Science and EMBASE including papers in English published from 1 January 1995 to 1 January 2023. A total of 1018 publications were screened, and 5 met the criteria for inclusion in this review.

RESULTS

Four distinct 3D models were described across five studies. Two models demonstrated objective benefits in the use of 3D-printed models in anatomical education in academic outcomes at all levels of learner medical experience and were well accepted by learners. One model utilised for preoperative visualisation demonstrated improved operative outcomes in complete mesocolic excision compared with preoperative imaging review, with a 22.1% reduction in operative time (p < 0.001), 9.2% reduction in surgical duration (p = 0.035) and 37.3% reduction in intraoperative bleeding volume amongst novice surgeons (p < 0.01). Technical simulation has been demonstrated in a feasibility context in one model but remains limited in scope and application on account of the characteristics of available printing materials.

CONCLUSIONS

3D printing is well accepted and effective for anatomic education and preoperative procedural planning amongst colorectal surgeons, trainees and medical students but remains a technology in the early stages of its possible application. Technological advancements are required to improve the tissue realism of 3D-printed organ models to achieve greater fidelity and provide realistic colorectal surgical simulations.