Innovation in the imaging perianal fistula: a step towards personalised medicine

The role of MRI in perianal fistulizing disease: diagnostic imaging and classification systems to monitor disease activity

Perianal fistulizing disease, commonly associated with Crohn's disease, poses significant diagnostic and therapeutic challenges due to its complex anatomy and high recurrence rates. Radiological imaging plays a pivotal role in the accurate diagnosis, classification, and management of this condition. This article reviews the current radiological modalities employed in the evaluation of perianal fistulizing disease, including magnetic resonance imaging (MRI), endoanal ultrasound, and computed tomography (CT). MRI, recognized as the gold standard, offers superior soft tissue contrast and multiplanar capabilities, facilitating detailed assessment of fistula tracts and associated abscesses. CT, although less detailed than MRI, remains valuable in acute settings for detecting abscesses and guiding drainage procedures. This article discusses the advantages and limitations of each modality, highlights the importance of standardized imaging protocols, and underscores the need for interdisciplinary collaboration in the management of perianal fistulizing disease. Future directions include advancements in imaging techniques and the integration of artificial intelligence to enhance diagnostic accuracy and treatment outcomes.

Clinical applications of 3D printing in colorectal surgery: A systematic review

BACKGROUND

The utilization of three-dimensional printing has grown rapidly within the field of surgery over recent years. Within the subspecialty of colorectal surgery, the technology has been used to create personalized anatomical models for preoperative planning, models for surgical training, and occasionally customized implantable devices and surgical instruments. We aim to provide a systematic review of the current literature discussing clinical applications of three-dimensional printing in colorectal surgery.

METHODS

Full-text studies published in English which described the application of 3D printing in pre-surgical planning, advanced surgical planning, and patient education within the field of colorectal surgery were included. Exclusion criteria were duplicate articles, review papers, studies exclusively dealing with surgical training and/or education, studies which used only virtual models, and studies which described colorectal cancer only as it pertained to other organs.

RESULTS

Eighteen studies were included in this review. There were two randomized controlled trials, one retrospective outcomes study, five case reports/series, one animal model, and nine technical notes/feasibility studies. There were three studies on advanced surgical planning/device manufacturing, six on pre-surgical planning, two on pelvic anatomy modeling, eight on various types of anatomy modeling, and one on patient education.

CONCLUSIONS

While more studies with a higher level of evidence are needed, the findings of this review suggest many promising applications of three-dimensional printing within the field of colorectal surgery with the potential to improve patient outcomes and experiences.

Validation of a 3D-printed model of cryptoglandular perianal fistulas

INTRODUCTION

Visualising the course of a complex perianal fistula on imaging can be difficult. It has been postulated that three-dimensional (3D) models of perianal fistulas improve understanding of the perianal pathology, contribute to surgical decision-making and might even improve future outcomes of surgical treatment. The aim of the current study is to investigate the accuracy of 3D-printed models of perianal fistulas compared with magnetic resonance imaging (MRI).

METHODS

MRI scans of 15 patients with transsphincteric and intersphincteric fistulas were selected and then assessed by an experienced abdominal and colorectal radiologist. A standardised method of creating a 3D-printed anatomical model of cryptoglandular perianal fistula was developed by a technical medical physicist and a surgeon in training with special interest in 3D printing. Manual segmentation of the fistula and external sphincter was performed by a trained technical medical physicist. The anatomical models were 3D printed in a 1:1 ratio and assessed by two colorectal surgeons. The 3D-printed models were then scanned with a 3D scanner. Volume of the 3D-printed model was compared with manual segmentation. Inter-rater reliability statistics were calculated for consistency between the radiologist who assessed the MRI scans and the surgeons who assessed the 3D-printed models. The assessment of the MRI was considered the 'gold standard'. Agreement between the two surgeons who assessed the 3D printed models was also determined.

RESULTS

Consistency between the radiologist and the surgeons was almost perfect for classification (κ = 0.87, κ = 0.87), substantial for complexity (κ = 0.73, κ = 0.74) and location of the internal orifice (κ = 0.73, κ = 0.73) and moderate for the percentage of involved external anal sphincter in transsphincteric fistulas (ICC 0.63, ICC 0.52). Agreement between the two surgeons was substantial for classification (κ = 0.73), complexity (κ = 0.74), location of the internal orifice (κ = 0.75) and percentage of involved external anal sphincter in transsphincteric fistulas (ICC 0.77).

CONCLUSIONS

Our 3D-printed anatomical models of perianal fistulas are an accurate reflection of the MRI. Further research is needed to determine the added value of 3D-printed anatomical models in preoperative planning and education.

Exploring methods of improving patient understanding and communication in a complex anal fistula clinic: results from a randomized controlled feasibility study

AIM

Patient understanding of disease can guide decision-making in the management of anal fistula. This prospective feasibility study aimed to assess the acceptability and methods of assessing the impact of viewing realistic models on patients with anal fistula.

METHODS

New referrals to a tertiary clinic participated in this single-centre, parallel-group randomized controlled study. Baseline characteristics, Decisional Conflict Scale and understanding of disease were assessed pre-consultation. Participants were randomized to a standard consultation, where disease and treatment options were explained using magnetic resonance images and drawn diagrams, or a similar consultation supplemented with an appropriate generic three-dimensional (3D) printed model. Understanding of disease and proposed surgery, Decisional Conflict Scale and ratings of visual aids were assessed post-consultation, along with 3D model feedback.

RESULTS

All 52 patients who were approached agreed to be randomized (25 standard, 27 3D consultation). Understanding of disease increased post-consultation in both groups. Post-consultation decisional conflict (0, no; 100, high decisional conflict) was low (median 27 post-standard vs. 24 post-3D consultation). Patients scored highly on measures assessing understanding of proposed surgery. 3D models were rated highly, with 96% of patients wanting to see them again in future consultations.

CONCLUSIONS

Three-dimensional printed fistula models are a welcome addition to outpatient consultations with results suggesting that understanding of surgery is improved. A future trial should be powered to detect whether 3D models result in a significant improvement in understanding beyond traditional methods of explanation and explore the conditions in which models have their maximal utility.

CLINICALTRIALS

GOV REGISTRATION ID

This study was registered on ClinicalTrials.gov (ID: NCT04069728). Registered on 23 August 2019.

Multimodality Imaging to Direct Management of Primary and Recurrent Rectal Adenocarcinoma Beyond the Total Mesorectal Excision Plane

Rectal tumors extending beyond the total mesorectal excision (TME) plane (beyond-TME) require particular multidisciplinary expertise and oncologic considerations when planning treatment. Imaging is used at all stages of the pathway, such as local tumor staging/restaging, creating an imaging-based "roadmap" to plan surgery for optimal tumor clearance, identifying treatment-related complications, which may be suitable for radiology-guided intervention, and to detect recurrent or metastatic disease, which may be suitable for radiology-guided ablative therapies. Beyond-TME and exenterative surgery have gained acceptance as potentially curative procedures for advanced tumors. Understanding the role, techniques, and pitfalls of current imaging techniques is important for both radiologists involved in the treatment of these patients and general radiologists who may encounter patients undergoing surveillance or patients presenting with surgical complications or intercurrent abdominal pathology. This review aims to outline the current and emerging roles of imaging in patients with beyond-TME and recurrent rectal malignancy, focusing on practical tips for image interpretation and surgical planning in the beyond-TME setting. Keywords: Abdomen/GI, Rectum, Oncology © RSNA, 2024.

Introducing 3D modelling of MRI in the preoperative mapping of perianal fistula: How it could help the surgeons?

Background

Surgeons find treating perianal fistula difficult because insufficient drainage and failure to eradicate perianal sepsis could increase the risk of recurrence and postoperative complications. For better planning of the most suitable surgical technique, surgeons must consider the risk factors of recurrence with an accurate pre-operative assessment of perianal fistulae. The most common imaging method for grading primary perianal fistulas, identifying their complications, and locating occult extensions is magnetic resonance imaging (MRI). However, surgeons may find it challenging to read the lengthy reports of complex tracts, particularly for complicated patients. The creation of three-dimensional (3D) models has gained traction recently as a genuinely useful diagnostic tool for pre-operative planning. The authors evaluated the value of these surgical models. Inspecting the 3D models in addition to the routine two-dimensional study caused four out of five skilled colorectal surgeons to re-evaluate how far the fistulae extended. This made promise that 3D models would be helpful, simple to understand, and quick to interpret for colorectal surgeons. The purpose of the study is to assess the value of adding 3D modelling of MRI to standard two-dimensional MRI protocol for more accurate delineation of perianal fistula and its complications aiming at better surgical outcomes.

Results

Regarding 3D models, the highest degree of accuracy was in detecting supra-levator extension (100%) by both the third radiologist and the surgeon. There was a statistically high diagnostic inter-observer agreement between both, with a p-value < 0.0001. The highest inter-observer agreement was in the supra-levator extension (50/50, 100%), and the lowest agreement was in the side branches detection (44/50, 88%).

Conclusions

Pre-operative 3D MRI modelling provided the surgeon with a pre- and intra-operative road map that improved the surgeon’s orientation and ability to see complex perianal fistulas and their consequences, especially those with supra levator extension, thus helping the surgeon achieve better surgical results and decrease the preoperative risk factors of recurrence. Surgeons should utilise it in complex and recurrent cases reducing preoperative risk factors and improving outcomes. Although this technique is expensive, its cost–benefit ratio is low relative to recurrent hospitalisation and complications.

Three-Dimensional Printed Anatomic Models Derived From Magnetic Resonance Imaging Data: Current State and Image Acquisition Recommendations for Appropriate Clinical Scenarios

Three-dimensional (3D) printing technologies have been increasingly utilized in medicine over the past several years and can greatly facilitate surgical planning thereby improving patient outcomes. Although still much less utilized compared to computed tomography (CT), magnetic resonance imaging (MRI) is gaining traction in medical 3D printing. The purpose of this study was two-fold: 1) to determine the prevalence in the existing literature of using MRI to create 3D printed anatomic models for surgical planning and 2) to provide image acquisition recommendations for appropriate clinical scenarios where MRI is the most suitable imaging modality. The workflow for creating 3D printed anatomic models from medical imaging data is complex and involves image segmentation of the regions of interest and conversion of that data into 3D surface meshes, which are compatible with printing technologies. CT is most commonly used to create 3D printed anatomic models due to the high image quality and relative ease of performing image segmentation from CT data. As compared to CT datasets, 3D printing using MRI data offers advantages since it provides exquisite soft tissue contrast needed for accurate organ segmentation and it does not expose patients to unnecessary ionizing radiation. MRI, however, often requires complicated imaging techniques and time-consuming postprocessing procedures to generate high-resolution 3D anatomic models needed for 3D printing. Despite these challenges, 3D modeling and printing from MRI data holds great clinical promises thanks to emerging innovations in both advanced MRI imaging and postprocessing techniques. EVIDENCE LEVEL: 2 TECHNICAL EFFICATCY: 5.

Education and Training in Transanal Endoscopic Surgery and Transanal Total Mesorectal Excision

There is a paradigm shift in surgical training, and new tool and technology are being used to facilitate mastery of the content and technical skills. The transanal procedures for rectal cancer-transanal endoscopic surgery (TES) and transanal total mesorectal excision (TaTME)-have a distinct learning curve for competence in the procedures, and require special training for familiarity with the "bottom-up" anatomy, procedural risks, and managing complex cases. These procedures have been models for structured education and training, using multimodal tools, to ensure safe implementation of TES and TaTME into clinical practice. The goal of this work was to review the current state of surgical education, the introduction and learning curve of the TES and TaTME procedures, and the established and future models for education of the transanal procedures for rectal cancer.

The use of magnetic resonance imaging technique and 3D printing in order to develop a three-dimensional fistula model for patients with Crohn's disease: personalised medicine

Introduction

Preoperative evaluation of magnetic resonance (MR) images may not be sufficient for the precise planning of anal fistula surgery or for stem cell therapy. Three-dimensional (3D) printing allows one to obtain spatial structures in a 1 : 1 scale with unprecedented precision.

Aim

To combine magnetic resonance imaging (MRI) with 3D printing for more precise visualisation of perianal Crohn’s disease.

Material and methods

MRI at 1.5T and a 3D printer were used. DICOM (Digital imaging and communications in medicine) images were imported into 3D Slicer v.4.8.0. Firstly, anal fistula was modelled on the basis of axial images. Fistula locations, the anus and anal canal, were marked with different coloured markers. The last step was to mark the skin that was connected to the anus and contact areas of the fistula with the skin. The prepared models were then exported to an STL format file. The anal fistula model was printed using a 3D printer. The development of the model, including printing, took approximately 6 h.

Results and conclusions

The accessibility of a rotatable 3D model before surgery allows for a more precise detection of the location and the degree of perianal disease. Moreover, this may also lower the inter-observer bias connected with interpretation of complex MR imaging before planned surgery. Development of MRI image transfer to 3D printing and the decreasing cost of 3D printers suggests a promising future of this technology in medical applications.

Burden of disease and adaptation to life in patients with Crohn's perianal fistula: a qualitative exploration

BACKGROUND

Perianal fistulas are a challenging manifestation of Crohn's disease. Best medical and surgical therapy results in only about a third of patients remaining in remission at one year on maintenance treatment and sustained healing is often elusive. There is little published data on patient perspective of living with the condition or coping strategies in the face of non-curative/non-definitive treatment. We aimed to understand the experience of living with perianal fistula(s) and their impact on quality of life and routine functioning.

METHODS

This exploratory qualitative study used purposive sampling to recruit participants with current / previous diagnosis of Crohn's anal fistulas, from national IBD / bowel disease charities. The "standards for reporting qualitative research" (SRQR) recommendations were followed. Unstructured individual face-to-face interviews were audio recorded, transcribed and analysed thematically. Early themes were reviewed by the study team including patient advocates, clinicians and qualitative researchers.

RESULTS

Twelve interviews were conducted, achieving apparent data saturation. Three broad themes were uncovered: Burden of symptoms; Burden of treatment; and Impact on emotional, physical and social well-being. Each included several sub-themes, with considerable interplay between these. The impact of perianal fistula(s) on patients with CD is intense and wide reaching, negatively affecting intimate, close and social relationships. Fistulas cause losses in life and work-related opportunities, and treatments can be difficult to tolerate.

CONCLUSION

Crohn's perianal fistulas exert a heavy negative physical and emotional impact on patients. These findings will inform development of a patient reported outcome measure to assess treatment effectiveness and quality of life for patients living with this challenging condition.

Medical-surgical Combined Approach in Perianal Fistulizing Crohn's Disease (CD): Doing it Together

Fistulising perianal Crohn's disease (pCD) is an aggressive phenotype, and patients not only suffer from perianal manifestations but also a worsening course for their luminal disease. This article describes the 6 key steps clinicians need to consider when managing patients with pCD which include; (i) ensuring a prompt diagnosis, (ii) multi-disciplinary management, (iii) psychological support, (iv) using multimodal medical and surgical treatment strategies, (v) continually monitoring and optimising therapy and (vi) ensuring that patients have a way of accessing care if required. Patients with fistulising pCD often have an unpredictable disease course and complete remission can be elusive. As such, a considered and nuanced approach is essential keeping the wider multi-disciplinary team and the patient involved in all decision making.

The Use of Imaging for Synthetic Midurethral Slings

Ultrasound and magnetic resonance imaging can be used to image midurethral slings, which have may have complications such as pain. There is considerable misunderstanding regarding the utility of the different modalities. This article aims to review the current literature to identify the benefits and limitations of each imaging modality and identify the place that each should have for patients with midurethral sling complications. A literature search was performed, and all relevant articles were identified and reviewed. Different imaging modalities are complementary, but more research is required in this area.

Radiological Society of North America (RSNA) 3D Printing Special Interest Group (SIG) clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: abdominal, hepatobiliary, and gastrointestinal conditions

Background

Medical 3D printing has demonstrated value in anatomic models for abdominal, hepatobiliary, and gastrointestinal conditions. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness criteria for abdominal, hepatobiliary, and gastrointestinal 3D printing indications.

Methods

A literature search was conducted to identify all relevant articles using 3D printing technology associated with a number of abdominal pathologic processes. Each included study was graded according to published guidelines.

Results

Evidence-based appropriateness guidelines are provided for the following areas: intra-hepatic masses, hilar cholangiocarcinoma, biliary stenosis, biliary stones, gallbladder pathology, pancreatic cancer, pancreatitis, splenic disease, gastric pathology, small bowel pathology, colorectal cancer, perianal fistula, visceral trauma, hernia, abdominal sarcoma, abdominal wall masses, and intra-abdominal fluid collections.

Conclusion

This document provides initial appropriate use criteria for medical 3D printing in abdominal, hepatobiliary, and gastrointestinal conditions.

Inflammatory bowel disease position statement of the Italian Society of Colorectal Surgery (SICCR): Crohn's disease

The Italian Society of Colorectal Surgery (SICCR) promoted the project reported here, which consists of a position statement of Italian colorectal surgeons to address the surgical aspects of Crohn's disease management. Members of the society were invited to express their opinions on several items proposed by the writing committee, based on evidence available in the literature. The results are presented, focusing on relevant points. The present paper is not an alternative to available guidelines; rather, it offers a snapshot of the attitudes of SICCR surgeons about the surgical treatment of Crohn's disease. The committee was able to identify some points of major disagreement and suggested strategies to improve quality of available data and acceptance of guidelines.

Magnetic resonance imaging findings in patients with initial manifestations of perianal fistulas

BACKGROUND

Crohn's disease (CD) is a serious cause of perianal disease and the incidence is increasing in Saudi Arabia. MR imaging may document specific features that may help to foresee Crohn's disease in patients making an initial presentation.

OBJECTIVE

Present MR imaging findings of perianal fistulas in patients making an initial presentation.

DESIGN

Retrospective, observational.

SETTING

Radiology clinic in in Dhahran.

PATIENTS AND METHODS

All previously undiagnosed and untreated patients who presented for the first time to the outpatient clinics from September 2015-2018 with perianal fistulas were retrospectively evaluated. Previously diagnosed CD patients, post-surgical or intervention cases were excluded. Fistulas were categorized as low or high anal, simple or complex, and were graded per St. James University Hospital Classification. Imaging was interpreted by two experienced readers based on the Van Assche score.

MAIN OUTCOME MEASURES

Fistula features on MR imaging and diagnosis of CD.

SAMPLE SIZE

171 patients.

RESULTS

Of 171 patients, 139 (81.3%) were males with mean age of 37.2 (12.7) years; the 32 females had a mean age of 35.8 (10.6) years. Twenty-one patients (12.3%) had CD. Fourteen (40.4%) patients with complex fistulas had CD in comparison to only 5 (4.8%) simple fistula patients ( P=.0005). More than half of patients with complex and high anal fistulas had CD ( P=.0005). Females were more affected than males ( P=.0005).

CONCLUSION

Complex or high anal fistula on MR imaging may be the initial presentation of CD and warrant further work up to establish the diagnosis.

LIMITATIONS

Retrospective, small sample, single center, and short duration study.

CONFLICT OF INTEREST

None.

Preoperative MRI of perianal fistula evaluation and its impact on surgical outcome

Background

Perianal fistula (PAF) is an abnormal tract communicating an external cutaneous opening in the perianal region to the anal canal. PAF is one of the common anorectal disorders in surgical practice with high prevalence. The current study aimed to determine the ability of preoperative MRI for preoperative evaluation of perianal fistula.

Results

This is a retrospective evaluation of 65 patients with perianal fistula. MRI fistula imaging-related data were revised, and fistula severity was scored using criteria of both local extension of fistulas and active inflammation for a total maximum score of 22. Preoperative MRI could predict the severity of perianal disease with sensitivity, specificity, and accuracy rates of 75%, 92%, and 84.6%, respectively. Surgical findings concerning PAF severity correlated significantly with MRI findings. Diffusion-weighted magnetic resonance imaging (DW-MRI) provided high sensitivity and accuracy with 100% specificity for fistula visualization and highest sensitivity, specificity, and accuracy for detection of cavities > 3 mm in diameter. DW-MRI provided the highest specificity rate on ROC curve analysis among the three MRI pulse sequences (DW-MRI, short tau inversion recovery (STIR), and T1 post-contrast).

Conclusion

MRI is valuable and accurate for preoperative investigation for PAF evaluation and abscess localization. MRI allowed accurate detection of internal fistula opening and its relation to sphincters. DW-MRI is a valuable sequence with highest diagnostic yield, and its addition to STIR WI improves sensitivity and specificity for determination of fistula activity and extension.

An overview on 3D printing for abdominal surgery

BACKGROUND

Three-dimensional (3D) printing is a disruptive technology that is quickly spreading to many fields, including healthcare. In this context, it allows the creation of graspable, patient-specific, anatomical models generated from medical images. The ability to hold and show a physical object speeds up and facilitates the understanding of anatomical details, eases patient counseling and contributes to the education and training of students and residents. Several medical specialties are currently exploring the potential of this technology, including general surgery.

METHODS

In this review, we provide an overview on the available 3D printing technologies, together with a systematic analysis of the medical literature dedicated to its application for abdominal surgery. Our experience with the first clinical laboratory for 3D printing in Italy is also reported.

RESULTS

There was a tenfold increase in the number of publications per year over the last decade. About 70% of these papers focused on kidney and liver models, produced primarily for pre-interventional planning, as well as for educational and training purposes. The most used printing technologies are material jetting and material extrusion. Seventy-three percent of publications reported on fewer than ten clinical cases.

CONCLUSION

The increasing application of 3D printing in abdominal surgery reflects the dawn of a new technology, although it is still in its infancy. The potential benefit of this technology is clear, however, and it may soon lead to the development of new hospital facilities to improve surgical training, research, and patient care.

Systematic review of the applications of three-dimensional printing in colorectal surgery

AIM

Three-dimensional (3D) printing has been recognized as a revolutionary technological innovation that has benefitted numerous disciplines, including medicine. The present systematic review aimed to demonstrate the current applications of 3D printing in colorectal surgery along with the limitations and potential future applications of this innovation.

METHOD

A PRISMA-compliant systematic literature search of studies that applied 3D printing in colorectal surgery in the period from January 1990 to July 2018 was conducted. Electronic databases including PubMed/Medline, Scopus and the Cochrane Library were searched. All full-text original articles were eligible for inclusion.

RESULTS

Nine studies including 58 patients with a median age of 60.7 years were reviewed. The studies assessed 3D printing in patients with planned stoma construction, colon cancer with liver metastasis, right colon cancer, rectal cancer, intractable constipation and anal fistula. The applications of 3D printing were classified into three categories: patient education, preoperative planning and evaluation of response of colorectal liver metastasis to chemotherapy. 3D printed models aided in planning resection of colorectal liver metastasis, facilitating D3 lymphadenectomy in complete mesocolic excision, improving the understanding of pelvic anatomy in laparoscopic rectal cancer treatment, guiding electrode implantation in sacral neuromodulation for intractable constipation, and elucidating the morphology of anal fistula tract and anal sphincter muscles.

CONCLUSION

Colorectal surgery may benefit from 3D printing in enhancing patient education before stoma construction, preoperative planning and evaluation of the response of liver metastasis to chemotherapy using 3D ultrasonography.

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

BACKGROUND

Three-dimensional (3D) printing is an emerging and evolving technology with a variety of possible applications in surgery. The purpose of this study was to examine its potential applications in the field of colorectal surgery, as a tool in pre-operative planning and peri-operative navigation, as well as in training. Its cost-efficiency was also examined.

MATERIALS AND METHODS

A literature review was conducted on articles specifically presenting various applications of 3D printing in the field of colorectal surgery. PubMed was the primary database researched.

RESULTS

A total of seven studies were found to meet the inclusion criteria. The majority of the articles employed 3D printing technology to produce patient-specific anatomic replicas to enhance pre-operative planning, providing satisfactory results. One study used 3D printing technology as a therapy tool, stating superior results over traditional methods.

CONCLUSION

3D printing is a novel technology with a broad spectrum of possible applications in colorectal surgery. Anatomic replicas specific to the anatomy of a patient with acceptable dimensional correlations can be produced using the currently available technology. Surgical and patient training can also be enhanced. Depending on the technology used, costs greatly vary and can thus hinder popularization of this technology in surgery.