The Role of 3D Printing in Colorectal Surgery: Current Evidence and Future Perspectives

Bioprinting the future using light: A review on photocrosslinking reactions, photoreactive groups, and photoinitiators

Light-based bioprinting is a type of additive manufacturing technologies that uses light to control the formation of biomaterials, tissues, and organs. It has the potential to revolutionize the adopted approach in tissue engineering and regenerative medicine by allowing the creation of functional tissues and organs with high precision and control. The main chemical components of light-based bioprinting are activated polymers and photoinitiators. The general photocrosslinking mechanisms of biomaterials are described, along with the selection of polymers, functional group modifications, and photoinitiators. For activated polymers, acrylate polymers are ubiquitous but are made of cytotoxic reagents. A milder option that exists is based on norbornyl groups which are biocompatible and can be used in self-polymerization or with thiol reagents for more precision. Polyethylene-glycol and gelatin activated with both methods can have high cell viability rates. Photoinitiators can be divided into types I and II. The best performances for type I photoinitiators are produced under ultraviolet light. Most alternatives for visible-light-driven photoinitiators were of type II, and changing the co-initiator along the main reagent can fine-tune the process. This field is still underexplored and a vast room for improvements still exist, which can open the way for cheaper complexes to be developed. The progress, advantages, and shortcomings of light-based bioprinting are highlighted in this review, with special emphasis on developments and future trends of activated polymers and photoinitiators.

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.

3D-printed heart models for hands-on training in pediatric cardiology - the future of modern learning and teaching?

BACKGROUND

This project aims to develop a new concept in training pediatric cardiologists to meet the requirements of interventional cardiac catheterizations today in terms of complexity and importance. This newly developed hands-on training program is supposed to enable the acquisition of certain skills which are necessary when investigating and treating patients in a catheter laboratory.

METHODS

Based on anonymous CT-scans of pediatric patients' digital 3D heart models with or without cardiac defects were developed and printed three-dimensionally in a flexible material visible under X-ray. Hands-on training courses were offered using models of a healthy heart and the most common congenital heart defects (CHD). An evaluation was performed by quantifying fluoroscopy times (FL-time) and a questionnaire.

RESULTS

The acceptance of theoretical and practical contents within the hands-on training was very positive. It was demonstrated that it is possible to master various steps of a diagnostic procedure and an intervention as well as to practice and repeat them independently which significantly reduced FL-time. The participants stated that the hands-on training led to more confidence in interventions on real patients.

CONCLUSION

With the development of a training module using 3D-printed heart models, basic and advanced training in the field of diagnostic cardiac examinations as well as interventional therapies of CHD is possible. The learning effect for both, practical skills and theoretical understanding, was significant which underlines the importance of integrating such hands-on trainings on 3D heart models in education and practical training.

Evaluation of the SYNAPSE VINCENT for lateral lymph node dissection in rectal cancer with robotic surgery: a preliminary report

Background

Even if 3D angiographic images of preoperative contrast-enhanced computed tomography (CT) are created, the coronal and axial sections can be unclear, and thus, it is difficult to achieve projection awareness similar to that of actual laparoscopic images. In recent years, the technology of analyzing and applying medical images has advanced, and surgical simulation and navigation have been widely used to improve the safety of surgical operations. It is important to understand pelvic anatomy in the area of rectal cancer, and use of the SYNAPSE VINCENT makes it possible to simulate the anatomy before surgery, which is very useful in educating surgeons and their assistants.

Materials and methods

An important objective in surgery is to understand the anatomy of the external/internal iliac arteries and lymph nodes in lateral lymph node dissection (LLD) for rectal cancer. In this study, we explored the accuracy and usefulness of SYNAPSE VINCENT images of pelvic anatomy (especially vascular anatomy) analyzed preoperatively in two cases of LLD for rectal cancer in our department.

Results

The patients were two men aged 73 and 57 years, respectively. Both patients underwent robotic abdominal perineal resection and LLD with neoadjuvant chemoradiotherapy. The operating times for LLD were 138 and 106 min, estimated blood loss was less than 10 mL and 20 mL, and the harvested lymph nodes were nos. 21 and 22, respectively. The SYNAPSE VINCENT could be used for simulation and navigation before and during surgery. For experienced surgeons, the system helped them carry out operations more accurately.

Conclusion

In the future, surgical support using virtual reality, augmented reality, and mixed reality based on medical images will be useful and is expected to improve the safety, accuracy, and efficiency of surgery, which is extremely useful for both young and skilled surgeons preparing for difficult operations.

Development of a 3D printed patient-specific neonatal brain simulation model using multimodality imaging for perioperative management

BACKGROUND

Medical-imaging-based three-dimensional (3D) printed models enable improvement in skills training, surgical planning, and decision-making. This pilot study aimed to use multimodality imaging and to add and compare 3D ultrasound as a future standard to develop realistic neonatal brain models including the ventricular system.

METHODS

Retrospective computed tomography (CT), magnetic resonance imaging (MRI), and 3D ultrasound-based brain imaging protocols of five neonatal patients were analyzed and subsequently segmented with the aim of developing a multimodality imaging-based 3D printed model. The ventricular anatomy was analyzed to compare the MRI and 3D ultrasound modalities.

RESULTS

A realistic anatomical model of the neonatal brain, including the ventricular system, was created using MRI and 3D ultrasound data from one patient. T2-weighted isovoxel 3D MRI sequences were found to have better resolution and accuracy than 2D sequences. The surface area, anatomy, and volume of the lateral ventricles derived from both MRI and 3D ultrasound were comparable.

CONCLUSIONS

We created an ultrasound- and MRI-based 3D printed patient-specific neonatal brain simulation model that can be used for perioperative management. To introduce 3D ultrasound as a standard for 3D models, additional dimensional correlations between MRI and ultrasound need to be examined.

IMPACT

We studied the feasibility of implementing 3D ultrasound as a standard for 3D printed models of the neonatal brain. Different imaging modalities were compared and both 3D isotropic MRI and 3D ultrasound imaging are feasible for printing neonatal brain models with good dimensional accuracy and anatomical replication. Further dimensional correlations need to be defined to implement it as a standard to produce 3D printed models.

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

BACKGROUND

Three-dimensional (3D) modelling technology translates the patient-specific anatomical information derived from two-dimensional radiological images into virtual or physical 3D models, which more closely resemble the complex environment encountered during surgery. It has been successfully applied to surgical planning and navigation, as well as surgical training and patient education in several surgical specialties, but its uptake lags behind in colorectal surgery. Rectal cancer surgery poses specific challenges due to the complex anatomy of the pelvis, which is difficult to comprehend and visualise.

AIM

To review the current and emerging applications of the 3D models, both virtual and physical, in rectal cancer surgery.

METHODS

Medline/PubMed, Embase and Scopus databases were searched using the keywords “rectal surgery”, “colorectal surgery”, “three-dimensional”, “3D”, “modelling”, “3D printing”, “surgical planning”, “surgical navigation”, “surgical education”, “patient education” to identify the eligible full-text studies published in English between 2001 and 2020. Reference list from each article was manually reviewed to identify additional relevant papers. The conference abstracts, animal and cadaveric studies and studies describing 3D pelvimetry or radiotherapy planning were excluded. Data were extracted from the retrieved manuscripts and summarised in a descriptive way. The manuscript was prepared and revised in accordance with PRISMA 2009 checklist.

RESULTS

Sixteen studies, including 9 feasibility studies, were included in the systematic review. The studies were classified into four categories: feasibility of the use of 3D modelling technology in rectal cancer surgery, preoperative planning and intraoperative navigation, surgical education and surgical device design. Thirteen studies used virtual models, one 3D printed model and 2 both types of models. The construction of virtual and physical models depicting the normal pelvic anatomy and rectal cancer, was shown to be feasible. Within the clinical context, 3D models were used to identify vascular anomalies, for surgical planning and navigation in lateral pelvic wall lymph node dissection and in management of recurrent rectal cancer. Both physical and virtual 3D models were found to be valuable in surgical education, with a preference for 3D printed models. The main limitations of the current technology identified in the studies were related to the restrictions of the segmentation process and the lack of 3D printing materials that could mimic the soft and deformable tissues.

CONCLUSION

3D modelling technology has potential to be utilised in multiple aspects of rectal cancer surgery, however, it is still at the experimental stage of application in this setting.

Minimally invasive gastrointestinal surgery: From past to the future

The improvement of the science and art of surgery began over 150 years ago. Surgical core tasks, “cutting and sewing” with hand and direct contact with the organs, have remained the same. However, in the 21st century, there has been a shifting paradigm in the methodology of surgery. The joint union between innovators, engineers, industry, and patient demands resulted in minimally invasive surgery (MIS). This method has influenced the techniques in every aspect of abdominal surgery, such as surgeons are not required to direct contact or see the structures on which they operate. Advances in the endoscope, imaging, and improved instrumentations convert the essential open surgery into the endoscopic method. Furthermore, computers and robotics show a promising future to facilitate complex procedures, enhance accuracy in microscale operations, and develop a simulation to improve the ability to face sophisticated approaches. MIS has been replacing open surgery due to improved survival, fewer complications, and rapid recoveries in recent years. Minimally invasive surgery's further research in diagnostic and therapeutic modalities is under investigation to achieve genuinely “noninvasive” surgery. Thus, MIS has gained interest in recent days and has been improving with promising outcomes.

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Minimally invasive surgery has interfered with multiple aspects of the surgical approach.

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Advancement in the endoscope, imaging, and other instrumentations shifting the current methodological conventional surgery.

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The benefit over risk is the promising primary outcome to achieve an exceptional quality of life.

Current and possible future role of 3D modelling within oesophagogastric surgery: a scoping review protocol

INTRODUCTION

Three-dimensional (3D) reconstruction describes the generation of either virtual or physically printed anatomically accurate 3D models from two-dimensional medical images. Their implementation has revolutionised medical practice. Within surgery, key applications include growing roles in operative planning and procedures, surgical education and training, as well as patient engagement and education. In comparison to other surgical specialties, oesophagogastric surgery has been slow in their adoption of this technology. Herein the authors outline a scoping review protocol that aims to analyse the current role of 3D modelling in oesophagogastric surgery and highlight any unexplored avenues for future research.

METHODS AND ANALYSIS

The protocol was generated using internationally accepted methodological frameworks. A succinct primary question was devised, and a comprehensive search strategy was developed for key databases (MEDLINE, Embase, Elsevier Scopus and ISI Web of Science). These were searched from their inception to 1 June 2020. Reference lists will be reviewed by hand and grey literature identified using OpenGrey and Grey Literature Report. The protocol was registered to the Open Science Framework (osf.io/ta789).Two independent reviewers will screen titles, abstracts and perform full-text reviews for study selection. There will be no methodological quality assessment to ensure a full thematic analysis is possible. A data charting tool will be created by the investigatory team. Results will be analysed to generate descriptive numerical tabular results and a thematic analysis will be performed.

ETHICS AND DISSEMINATION

Ethical approval was not required for the collection and analysis of the published data. The scoping review report will be disseminated through a peer-reviewed publication and international conferences.

REGISTRATION DETAILS

The scoping review protocol has been registered on the Open Science Framework (https://osf.io/ta789).

Minimally Invasive Surgery for Congenital Abdominal Cystic Lesions in Newborns and Infants

BACKGROUND/AIM

In the variety of congenital abdominal cystic lesions (CACL) of different origin, ovarian cyst is the most common intra-abdominal pathology in female neonates. The prognosis and timing of treatment varies depending on the nature of CACL. This study aimed to assess the results of diagnostics and treatment of CACL.

PATIENTS AND METHODS

A retrospective analysis was performed of 39 cases of CACL, with the spectrum including ovarian, enteric, mesenteric and pancreatic origin. Outcome of minimally invasive surgery, open surgery or conservative approach was analyzed.

RESULTS

Twenty-eight neonates underwent surgery, while 11 were treated conservatively. Twenty patients were treated with a laparoscopic technique and eight with laparotomy combined with laparoscopy. Final diagnosis included: Fifteen cases of ovarian pathology (ovarian torsion in 11 cases), 12 treated laparoscopically and three with laparotomy, six enteric duplications (four laparoscopic and two laparotomic), three mesenteric cysts (one laparoscopic and two laparotomic), two pancreatic cysts (both laparoscopic only), two duodenal stenoses, including duodenal septum (both laparotomies with Heineke-Mikulicz plasty). No blood transfusion apart from two cases requiring re-laparotomy and no early complications were observed in any case; no death occurred.

CONCLUSION

With the strategy of management based on ultrasound and laboratory data, a laparoscopically assisted minimal access approach resulted in minimal risk of complications and complete recovery in all patients, leading to exclusion of oncological risk.

Drug-loading three-dimensional scaffolds based on hydroxyapatite-sodium alginate for bone regeneration

Bone tissue engineering is a promising approach for tackling clinical challenges. Osteoprogenitor cells, osteogenic factors, and osteoinductive/osteoconductive scaffolds are employed in bone tissue engineering. However, scaffold materials remain limited due to their source, low biocompatibility, and so on. In this study, a composite hydrogel scaffold composed of hydroxyapatite (HA) and sodium alginate (SA) was manufactured using three-dimensional printing. Naringin (NG) and calcitonin-gene-related peptide (CGRP) were used as osteogenic factors in the fabrication of drug-loaded scaffolds. Investigation using animal experiments, as well as scanning electron microscopy, cell counting kit-8 testing, alkaline phosphatase staining, and alizarin red-D staining of bone marrow mesenchymal stem cell culture showed that the three scaffolds displayed similar physicochemical properties and that the HA/SA/NG and HA/SA/CGRP scaffolds displayed better osteogenesis than that of the HA/SA scaffold. Thus, the HA/SA scaffold could be a biocompatible material with potential applications in bone regeneration. Meanwhile, NG and CGRP doping could result in better and more positive proliferation and differentiation.