Keywords
colorectal surgery - 3D-printing - complex fistula - enterocutaneous fistula - ostomy
The rapid advancements in three-dimensional (3D)[1] printing technology has shown great potential for medicine.[2] From its conception in the early 1980s, 3D printing has evolved into a promising
technology with many commercial applications.[3] This method of rapid manufacturing involves the use of software and individual patient
data to create a 3D object from a two-dimensional digital image. The process involves
acquiring patient information through noninvasive imaging techniques, creation of
a 3D model through a computer-aided design (CAD) program, conversion of the CAD file
to a printing file (often STL), and printing with a 3D printing technique.[3] There are many types of 3D printing technologies such as vat photopolymerization,
material extrusion, and material jetting.[4]
[5]
Patient-specific surgical guides are currently in use in other areas of surgery and
in various stages of development.[6]
[7] Although the applications of 3D printing technology are mostly at the proof-of-concept
phase in colorectal surgery, the technology shows promise to transform the practice
of management of complex fistulae and ostomy creation.[8] Applications include creation of prosthetics, tools, and reproducing patient-specific
anatomy for patient counseling and education and also surgical planning.[9]
[10]
[11]
3D physical models can be produced based off volumetric scans such as computed tomography
(CT), magnetic resonance imaging, and ultrasound data to provide additional information
for the surgeon.[12] The use of these models have been widely documented in radiology, with guidance
for radiologists published.[13]
[14] The ability to create personalized and customized items from a wide array of materials
is another benefit. The increasing affordability of 3D printing technology also demonstrates
its economic feasibility.[4]
Although 3D printing research in surgery is mainly focused on plastics, maxillofacial,
and orthopaedic surgery,[9]
[11]
[15] one sector of medicine seeing great potential benefits is colorectal surgery. Due
to the highly variable and complex anatomy of the digestive tract, 3D printing has
the potential to assist patients, surgeons, and health care professionals in improving
patient outcomes. The area of colorectal surgery has seen the applications of this
technology, especially with assisting surgical planning and patient education.[16] Despite discussions by expert groups regarding 3D printing radiological applications
in colorectal surgery, specific stoma creation and fistula management was not discussed.[11] Patient-specific anatomical variation can be considered with the design of implants
that can be personalized to the complex environment encountered during surgery.[17]
Technical challenges of the complex anatomy of the digestive tract and problems faced
by patients with stomas and enterocutaneous (ECF) and enteroatmospheric fistulae (EAF)
are well documented in the literature.[18]
[19] However, the application of 3D printing in the area of stoma care and fistula management
remains relatively limited, and there is no comprehensive overview regarding stoma
creation and complex fistula management and 3D printing in colorectal surgery.
This scoping review encompasses the applications of 3D printing in ostomy creation
and ECF management, with its limitations and a brief overview of future recommendations
for research.
Methods
This scoping review was performed in accordance with the Preferred Reporting Items
for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines.
Search Strategy
An electronic search of all literature from the earliest available date up to and
including March 24, 2022, was done by two independent researchers (M.P. and K.S.).
The search terms used were (3D-print* OR additive manufactur* OR 3D print*) AND (“Colorectal
Surgery” OR Stoma OR Ileostomy OR Colostomy OR ostomy OR “Rectal cancer surgery” OR
Parastomal OR “Enterocutaneous fistula” OR “Enteroatmospheric fistula” OR “Intestinal
failure” OR “Colon cancer surgery”). Databases included PubMed, EMBASE, and CENTRAL.
A manual search of the references lists of articles found through the original search
was done to identify any further relevant studies.
Selection of Relevant Studies
All primary research articles reporting the use of 3D printing in colorectal surgery
or colorectal surgical patients were included. Studies were excluded if: (1) they
were performed in an animal model; (2) no full-text article was available; (3) the
full-text article was in a language other than English; (4) they were a review article;
and (5) they described applications of 3D printing for surgical education and training.
Following removal of duplicate abstracts, the remaining titles and abstracts were
screened independently by two reviewers (C.S. and M.P.). Any disagreements between
the two reviewers were resolved by automatic inclusion. Potentially eligible studies
were then retrieved for full-text assessment. All full texts of retrieved articles
were read and reviewed by two authors (C.S. and M.P.) to determine studies meeting
the eligibility criteria. Where there was discrepancy, a third reviewer (M.P.P.) made
the final decision.
Data Charting
Characteristics of the included studies were summarized by two authors (C.S. and M.P.)
in a Microsoft Excel data extraction spreadsheet designed a priori and modified iteratively.
The information extracted included: the primary author, study design, year of publication,
country of study, study population size, name of 3D printer, printer name, type of
surgical procedure concerned, type of 3D printing utilized, 3D printing method description,
name of software used for product design, printing material used, reported outcomes,
cost, main challenges reported, and future areas of study proposed. The descriptive
abstracted summaries of the included articles were reviewed and the two authors (C.S.
and M.P.) met to generate the core themes, which were: (1) applications of 3D printing
in stoma management, (2) applications of 3D printing in ECF management, and (3) applications
of 3D printing in patient education relating to stoma or ECF management.
Results
The literature search identified 106 articles, of which 92 were screened following
removal of duplicates and exclusion of non-English articles. In total, 8 articles
met the inclusion and exclusion criteria. [Fig. 1] illustrates the study selection process.
Fig. 1 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flowchart.
A flowchart describing the screening process of the articles, with n = 8.
Characteristics of the included studies are summarized in [Table 1]. Most of the included studies were conducted in Asia (Japan, Taiwan, and China,
n = 5),[20]
[21]
[22]
[23]
[24] with the others completed in Spain (n = 2)[25]
[26] and the United States (n = 1).[27] Four studies were of descriptive case study design,[22]
[23]
[24]
[27] two were quasi-experimental clinical trials,[25]
[26] and two were laboratory research studies.[20]
[21] Sample sizes were small across the reviewed literature, with only three studies
reporting the use of 3D-printed device in more than one patient.[23]
[25]
[26]
Table 1
Characteristics of articles included in the scoping review
|
Author
|
Year
|
Country
|
Type of study
|
Sample size
|
Disease of interest
|
|
Cosman et al27
|
2021
|
USA
|
Case report
|
1
|
Colostomy
|
|
Tominaga et al23
|
2016
|
Japan
|
Case report
|
5
|
Ileostomy and colostomy
|
|
Zahia et al26
|
2022
|
Spain
|
Quasi-experimental
|
9
|
Colostomy, ileostomy, or urostomy
|
|
Yeh et al20
|
2021
|
Taiwan
|
Laboratory research
|
0
|
Colostomy
|
|
Xu et al22
|
2019
|
China
|
Case report
|
1
|
Enteroatmospheric fistula
|
|
Durán Muñoz-Cruzado et al25
|
2020
|
Spain
|
Quasi-experimental
|
4
|
Enteroatmospheric fistula
|
|
Huang et al24
|
2017
|
China
|
Case report
|
1
|
Enterocutaneous fistula
|
|
Hu et al21
|
2021
|
China
|
Laboratory research
|
0
|
Enteroatmospheric fistula
|
Note: Articles and their details included within the review with basic details.
The applications of 3D printing described in the literature can be broadly divided
into three categories: production of paraphernalia to aid self-management of stoma,[23]
[27] production of ostomy appliances,[20]
[26] and production of appliances for the management of EAF or ECF.[21]
[22]
[24]
[25] The key findings of the included articles are detailed in [Table 2].
Table 2
Key findings of included studies
|
Study
|
Application of 3D printing
|
Software applications used
|
Type of 3D printing
|
3D printer utilized
|
Material used
|
Main findings
|
|
Cosman et al27 (2021)
|
Fabrication of flange stabilizer to help with ostomy patch adhesives changes in individuals
with impaired dexterity to minimize risk of stoma leakage
|
Fusion 360
|
Material extrusion
|
Prusa i3 MK2S
|
Polylactic acid (PLA)
|
General findings:
• Ostomy aid would be especially beneficial to ostomates with impaired dexterity
• Model published on open-access site that anyone with access to a 3D printer can
use to print this device
Advantages:
• Low cost of production (< $1)
Limitations:
• PLA neither autoclavable nor dishwasher safe
• Device optimized only for specific flange size
• Durability of device
|
|
Tominaga et al23 (2016)
|
Creating stoma and face plate models for patient education to improve daily stomal
care and reduce complications such as stoma-associated skin problems
|
Geomagic Free Form graphics
|
Vat photopolymerization
|
Objet 260 Connex
|
—
|
General findings:
• 3D-printed models useful for patient education on stomal care, especially so for
patients may find it challenging to learn new skills
• Models facilitate discussions at staff conferences and help in finding solutions
to stoma-related issues
• Could lead to less skin problems associated with daily stomal care
Advantages:
• Self-reliance in stomal care
• 3D models can be kept for use at home or in future outpatient clinic visits
Limitations:
• High cost (∼$100USD per patient)
• Lengthy process
• Change in stoma size during perioperative period
|
|
Zahia et al26 (2022)
|
Production of customized ostomy pouch adhesives to reduce the occurrence of complications
associated with change in parameters of ostomy over time and enhance patient quality
of life
|
3D Slicer, Creo Parametric, Meshlab
|
Vat photopolymerization
|
—
|
—
|
General findings:
• Feasible to use low-cost manual scanners to create 3D-printed stoma barrier rings
with little difference in quality and reliability
Advantages:
• Several benefits of using handheld scanner over CT scan for design of personalized
patch: reduced need for hospital resources and appointment, less complex data files,
quicker processing in design software
Limitations:
• Poor adhesion of ostomy pouch adhesives to skin
• Reported patch rupture and skin irritation
• Concerns regarding patch thickness compared with commercial patches
|
|
Yeh et al20 (2021)
|
Production of customized colostomy base plate to minimize stoma leakage
|
Not specified
|
Material extrusion
|
—
|
Thermoplastic elastomer (TPE)
|
General findings:
• It is possible to calibrate 3D printing parameters to achieve softness using low-cost
materials
Advantages:
• Manufacturing methods are modifiable to achieve desirable properties in 3D-printed
devices
Limitations:
• Only manufacturing materials, methods and 3D printing parameters discussed in this
study
|
|
Xu et al22 (2019)
|
Fabrication of fistula stent for EAF plugging to accelerate fistula closure
|
SolidWorks
|
Material extrusion
|
—
|
Thermoplastic polyurethane (TPU)
|
General findings:
• Novel 3D-printed fistula stent can significantly minimize volume of enteric effluent
loss and speed up rehabilitation
Advantages:
• Enteric effluent loss markedly reduced after stent placement
• Stent acts as temporary tract, allowing restoration of enteral nutrition
Limitations:
• Changes in the morphology and size of fistulous tract during therapy
• Stent may enlarge EAF and reduce likelihood of spontaneous closure
• Limited sample size
|
|
Durán Muñoz-Cruzado et al25 (2020)
|
Manufacturing customized prostheses for patients with complex EAF
|
FreeCad 0.16, Meshmixer, Regemat 3D designer software
|
Material extrusion
|
Regemat 3D
|
Polycaprolactone (PCL)
|
General findings:
• Feasible to design, produce, and use a customized device that suits the patient's
wound through 3D printing to achieve a “floating stoma”
Advantages:
• Reduced enteric effluent and associated skin complications
• Increased patient comfort and reduced need for analgesia
• Device generation process took 4 ± 0.45 h
Limitations:
• Issues with adherence between PCL material and negative pressure wound therapy system
that the stoma was connected to
|
|
Huang et al24 (2017)
|
Fabrication of patient-personalized fistula stent for ECF
|
SolidWorks
|
Material extrusion
|
—
|
Thermoplastic polyurethane (TPU)
|
General findings:
• Feasible to produce a stent specific to patient's fistula anatomy to reduce loss
of intestinal effluvium, patient nutrition and recovery, and local wound inflammation
Advantages:
• Less mechanical damage to surrounding mucosa compared with other plugging methods
• Reduction in loss of enteric effluent and greater tolerance to physical rehabilitation
• No endoscopic-guided implantation of stent required
Limitations:
• Limited sample size
|
|
Hu et al21 (2021)
|
Preparation of personalized stents for intestinal fistulas
|
Creo Parametric, CloudCompare
|
5 + 1-axis 3D printing
|
—
|
Thermoplastic polyurethane (TPU)
|
General findings:
• 5 + 1-axis 3D printing method devised through the study showed greater efficiency,
created better stent surface properties and shape, and optimal mechanical strength
and elasticity for human bioprostheses
Advantages:
• Better microstructure of stent produced with five-axis printing method, reducing
likelihood of intestinal fluid leak and electrolyte loss
• Orderly channel arrangement in stents allowing uniform adhesion of cells
Limitations:
• Potential utility, safety and efficacy of stents in vivo yet to be proven
• Biocompatibility of fistula stent with intestinal wall fibroblast lines yet to be
studied
|
Abbreviations: 3D, three-dimensional; CT, computed tomography; EAF, enteroatmospheric
fistulas; ECF, enterocutaneous fistulas.
Note: Describing studies and the main findings from each paper.
Applications of 3D Printing in Patient Education of Stoma Management
There were two studies identified describing the creation of product to aid patient
education and daily stomal care. Cosman et al presented the design and production
of a flange stabilizer that would help patients with impaired dexterity in performing
daily ostomy bag changes correctly, thus reducing the chance of leakage due to improper
pouch reattachment after emptying.[27] In a similar vein, Tominaga et al described the use of 3D-printed stoma models and
baseplates to allow patients to practice cutting their ostomy baseplate with the 3D
stoma model to minimize skin irritation associated with suboptimal daily stomal care.
Stoma care was found to be improved in all 5 patients trained using the 3D-printed
models.[23]
Applications of 3D Printing in Production of Ostomy Appliances
Two studies described the use of 3D printing in producing customized constituents
of the ostomy system.[20]
[26] Zahia et al conducted a clinical trial of the 3D-printed ostomy skin barrier to
evaluate the performance and safety of the devices. The study reported the feasibility
of using low-cost scanners over computed axial tomography (CT scans) to obtain 3D
images of the abdominal surface to design and print ostomy pouch adhesives without
compromising the reliability of the patch. Issues reported by the patients included
poor adhesion of the patch, patch rupture, skin irritation, and inadequate thickness,
but no differences were observed in the incidence of these between the patches printed
using different scanning modalities.[26] Yeh et al described an experiment using the Taguchi method to optimize 3D printing
parameters that would allow low-cost materials to achieve the appropriate softness
needed for an ostomy bag.[20]
Applications of 3D Printing in Production of Fistula Stents
Four studies explored the applications of 3D printing in producing stents for the
management of EAF or ECF.[21]
[22]
[24]
[25] All of the studies describe EAF and ECF as challenging conditions with high associated
morbidity if not managed properly initially. Given the immense variability in the
morphology of the fistulous orifice in patients, the necessity of a tailored approach
has been highlighted.[22]
[24]
[25] The 3D-printed fistula stent was reported to be effective in controlling intestinal
effluvium and achieving wound isolation in conjunction with negative pressure wound
therapy.[25] Hu et al described the development of a novel 5 + 1 axis 3D printing platform to
achieve more high-precision, customized intestinal fistula stents.[21] Scanning electron microscope analysis of stents produced with the traditional three-axis
printing method and those produced with the five-axis printing method showed superiority
of the latter stents in terms of regularity of the stent surface. The stents printed
using the new five-axis printing method devised were reported to be less likely to
lead to intestinal fluid leakage and electrolyte loss following implantation, as well
as provide a more favorable surface for adhesion of cells from the intestinal wall.[21]
3D Printing Technology
In terms of the 3D printing technology employed, material extrusion, also known as
fused deposition modeling (n = 5) and vat photopolymerization (n = 2) were most commonly used. The material used for device production was highly
variable, as different material properties were needed for the device described in
each study. Among the four studies that described the fabrication of a stent for EAF
or ECF management, three of them used thermoplastic polyurethane (TPU). This was attributed
to the biocompatibility and flexibility of the material.[21]
[22]
[24] Several factors are important to consider during material selection for medical
device production using 3D printing, including the physical properties of the material,
its printing difficulty, cost, sustainability, and environmental impact of the chosen
material.[20] The adherent property of the material used was also noted to be poor by several
authors and suggested the need for further developments in this area.[25]
[26]
Challenges and Recommendations
[Fig. 2] summarizes the main challenges and respective recommendations developed from the
literature with regards to future research being conducted in the field of 3D printing
and their applications in colorectal surgery.
Fig. 2 Graphic on challenges and recommendations. The figure describes the challenges and
solutions for implementation of three-dimensional (3D) printing in colorectal surgery.
Quality of Studies Found
Most research was low-grade with seven of the publications at or below level III evidence.
No randomized control trials (RCTs) were found with full information. A Cochrane-registered
trial was identified investigating the effect of having a preoperative education session
with the fitting of a 3D-printed stoma on the patients' quality of life compared with
felt-tip marking of the ostomy site. However, this study was excluded as it is still
ongoing with no results reported yet.[28]
Discussion
This scoping review provides the first summary of the applications of 3D printing
in the field of device creation in ostomy and ECT and EAF fistula management within
the field of colorectal surgery. The current level of knowledge remains limited with
only a small number of studies identified, despite there being a larger base of literature
for other applications of 3D printing within colorectal surgery with two existing
systematic reviews. Although the review's results demonstrate successes within different
approaches in the field, these must be considered in the context of their limitations
such as small sample sizes and recent applications. Many applications in colorectal
surgery remain at the “proof-of-concept” stage, and literature remains limited to
case reports. More focused research and larger scale trials involving larger patient
groups must be conducted to progress to adoption of these applications in clinical
practice. Health care professionals must be prepared to adopt 3D printing into health
practice, as usability and cost-effectiveness of these technologies increase with
new developments in the field, and to shape the new landscape in which 3D printing
is used in medicine. Current abdominal appropriateness criteria and guidelines by
specialist groups have not addressed our applications beyond anal fistulae.[1]
The studies could be subdivided into ostomy, ECF/EAF fistula, and patient education
devices. Most devices were designed to be personalized to each patient and used TPU
as materials. The specific technologies used were diverse, with a wide range of techniques
and approaches employed to design each device. However, the principles of 3D printing
remained consistent throughout, with many different modalities used to derive information
via scanning, design of the device, and subsequent printing and application.
Ostomy
Zahia et al show that ostomy pouch adhesives can be created via 3D printing technology
from information derived from different 3D scanning modalities.[26] Yeh et al demonstrate the design of a low-cost ostomy bag using 3D printing, although
it was not tested on any patients.[20] These studies demonstrate the proof-of-concept ideas that can be applied to future
studies with patient cohorts.
Fistula
The management of complex ECFs had the highest number of case reports, with a majority
originating from Asia. The reports describe the use of material extrusion alongside
thermoplastic urethane and polylactic acid to custom design patches that were personalized
to each patient's fistula. These proof-of-concept studies seek to block the EAF to
manage the condition in the short and long term, although challenges included wide
clinical variability and the device potentially changing the shape of the wound.[21]
[22]
[24]
[25]
Patient Models
Cosman et al describe a 3D-printed flange stabilizer for patients with spinal cord
injury.[27] Tominaga et al describe a case in which 3D-printed stoma models are used to discuss
care and problems with patients.[23] This study highlighted the effectiveness of 3D-printed models in teaching patients
with dementia management of ostomy devices. 3D-printed models can facilitate self-management
of ostomies in patients who might otherwise struggle due to their physical or mental
disabilities, which can lead to better compliance, patient autonomy, and outcomes.
Advantages and Disadvantages
Advantages and Disadvantages
3D printing has many advantages to traditional methods of device creation in the context
of colorectal surgery. Advantages described in the included papers were reduced hospital
length of stay, quicker recovery, and restoration of bowel function through the use
of an ostomy. Patients were able to be discharged at an earlier date and this has
additional advantages for the hospital. The studies also identified the quick process
of creation and manufacturing the devices using 3D printing, alongside the availability
of the materials used. Most studies described using thermoplastic materials, which
has mechanical strength, flexibility, and biocompatibility.[29] One study described modifications in printing technique to optimize the material
properties of the devices used to fabricate the products. The general desirable characteristics
were materials that were lightweight and strong to allow patients to continue with
normal life with comfort and reduce the strain placed on the delicate tissues. Much
consideration is given to the setup of the 3D printers and the thickness and infill
settings, alongside optimization of the software files used. The files were stored
digitally and modified as required, with changing patient measurements. This customization
allows a more accurate fidelity and representation of the device required for the
patients. The accuracy of the replication of these models are yet to be studied, with
potential error factors such as limitations of the technology and model inaccuracies.[8] In addition, cost considerations and waste reduction using the process of 3D printing
in comparison to traditional manufacturing methods makes it an advantageous avenue
to continue research. Cost savings in other fields of medicine such as orthopaedic
surgery and general medicine have been attributed to reduction in procedural and operative
times, although one must be careful with extending this assumption to colorectal surgery
as the needs for printing applications vary.[30]
[31]
Nevertheless, the limitations of 3D printing technology are that it is yet to be employed
on a wider scale in clinical practice. A common drawback observed in the articles
included issues with fit within changing anatomy and compromised viability of the
skin and soft tissues. The relative inaccessibility of the software used to novices
or untrained clinicians, as noted in many of the studies involved collaboration with
engineering departments and expert consultants, may be a potential barrier to its
adoption. The process of designing a customized product with complex dimensions without
the necessary engineering expertise may be a long and arduous process. Although open-source
designs exist for free online, concerns regarding lack of regulation and expertise
limit its use. Studies on the viability and long-term safety of these devices are
yet to be conducted.
Publication Bias
A recognized source of bias in reviews is publication bias, which describes the trend
that studies with statistically and clinically significant findings tend to be more
likely to be published than their counterpart with no or little significant findings.
In addition, the potential detrimental statistical false positive influence of publication
bias, particularly in small to medium samples, together with high heterogeneity in
study methods and 3D printing methods, has meant that conducting a meta-analysis would
have not been feasible.
Future Directions
The lack of literature and robust evidence available on 3D printing in colorectal
surgery is a significant limitation. A common issue is the lack of patient data and
the low level of evidence, as many of the studies were case descriptions with single
individuals. It is not possible to extrapolate such data, and more trials and studies
must be conducted with 3D printing and colorectal surgery. A recommendation for future
research is to automate the 3D printing process for the novice user, and to make these
technologies available in developing countries as an accessible low-cost tool.[25]
[26]
Conclusion
This scoping review has reaffirmed that 3D printing has a promising role in terms
of management of complex intestinal fistulae and in ostomy creation. It has been shown
to improve outcomes in terms of recovery, fluid loss, and function with no increase
in complications. However, the use of 3D printing in colorectal surgery remains nascent
and further research in the form of RCTs to improve methodological robustness will
reveal its true potential.
