Clinical application of three-dimensional printing technology in craniofacial plastic surgery

The Use and Outcomes of 3D Printing in Pediatric Craniofacial Surgery: A Systematic Review

Three-dimensional (3D) printing has demonstrated efficacy in multiple surgical specialties. As accessibility improves, its use in specific fields deserves further attention. We conducted a systematic review of the implementation and outcomes of 3D printing in pediatric craniofacial surgery, as none has been performed. A systematic review was conducted according to Cochrane and PRISMA guidelines. PubMed, Embase, Cochrane library, and Clinicaltrials.gov were queried with combinations of the terms: "3D printing," "craniofacial," "surgery," and "pediatric." Original human studies containing patients <18 years old implementing 3D printing to aid in craniofacial surgery were included. Study selection, grading, and data extraction were performed independently by multiple authors. After screening 120 articles, 7 (3 case series and 4 case reports) were included, published from 2017 to 2022. All studies addressed patients with different disease processes including craniosynostosis, cleft lip/palate, and mandibular hypoplasia. 3D printing was used to create mock surgical models in 2 studies, intraoperative cutting guides/molds (CGs) in 6 studies, and cranioplasty implants in 2 studies. Two case series determined the accuracy of the CGs was acceptable within historical comparison, while 4 articles included subjective statements on improved accuracy. Five studies noted reduced operating time, 2 noted reduced intraoperative blood loss, and 1 felt the use of 3D printed materials was responsible for shorter hospitalization duration. No adverse events were reported. Despite the limitations of the current literature, all studies concluded that the use of 3D printing in pediatric craniofacial surgery was beneficial. Definitive conclusions cannot be made until further controlled research is performed.

The performance tests of three-dimensional printing titanium alloy craniomaxillofacial bone plate: A preliminary preclinical study

Background/purpose

Because of the complex anatomical structure of the maxillofacial skeleton, bending plates is necessary during surgery. The fast developing three-dimensional printing (3DP) technology has provided a new method for making personalized craniomaxillofacial bone plates. However, the properties of these bone plates remain unknown. This study evaluates the mechanical, fatigue, and morphological properties of these bone plates, which may provide data supporting future clinical applications.

Materials and methods

The 3DP bone plate was fabricated by selective laser melting (SLM) and electron beam melting (EBM) technologies. Mechanical, surface, and defect analyses were performed to compare their properties with a standard machined sample. One-way analysis of variance was applied, with p < 0.05 considered significant.

Results

The 3DP craniomaxillofacial bone plate had better bending strength than that of the standard machined plate (p < 0.01). Whereas the fatigue resistance of the 3DP bone plate needs to be improved in the future. Surface analysis indicated greater roughness of the 3DP bone plate (p < 0.01). However, the surface roughness could be significantly reduced by polishing the surface, which would meet the needs of clinical application after polishing. Further defect analysis revealed the internal defect inside the plate, which should be avoided to improve the mechanical strength of the printed sample in the future.

Conclusion

The 3DP titanium craniomaxillofacial bone plate has good mechanical performance and surface morphology, meeting the requirements of clinical application. However, poorer fatigue resistance and a high number of internal defects should be modified in the future.

Investigation on Filaments for 3D Printing of Nasal Septum Cartilage Implant

Septoplasty is a widely used method in treating deviated septum. Although it is successfully implemented, there are problems with excessive bleeding, septal perforation, or infections. The use of anatomically shaped implants could help overcome these problems. This paper focuses on assessing the possibility of the usage of a nasal septum cartilage implant 3D printed from various market-available filaments. Five different types of laments were used, two of which claim to be suitable for medical use. A combination of modeling, mechanical (bending, compression), structural (FTIR), thermal (DSC, MFR), surface (contact angle), microscopic (optical), degradation (2 M HCl, 5 M NaOH, and 0.01 M PBS), printability, and cell viability (MTT) analyses allowed us to assess the suitability of materials for manufacturing implants. Bioflex had the most applicable properties among the tested materials, but despite the overall good performance, cell viability studies showed toxicity of the material in MTT test. The results of the study show that selected filaments were not suitable for nasal cartilage implants. The poor cell viability of Bioflex could be improved by surface modification. Further research on biocompatible elastic materials for 3D printing is needed either by the synthesis of new materials or by modifying existing ones.

Two-Dimensional Post-Traumatic Measurements of Orbital Floor Blowout Fractures Underestimate Defect Sizes Compared to Three-Dimensional Approaches

Orbital floor fractures represent a common fracture type of the midface and are standardly diagnosed clinically as well as radiologically using linear measurement methods. The aim of this study was to evaluate the accuracy of diagnostic measurements of isolated orbital floor fractures based on two-dimensional (2D) and three-dimensional (3D) measurement techniques. A cohort of 177 patients was retrospectively and multi-centrically evaluated after surgical treatment of an orbital floor fracture between 2010 and 2020. In addition to 2D and 3D measurements of the fracture area, further fracture-related parameters were investigated. Calculated fracture areas using the 2D measurement technique revealed an average area of 287.59 mm², whereas the 3D measurement showed fracture areas with a significantly larger average value of 374.16 mm² (p < 0.001). On average, the 3D measurements were 1.53-fold larger compared to the 2D measurements. This was observed in 145 patients, whereas only 32 patients showed smaller values in the 3D-based approach. However, the process duration of the 3D measurement took approximately twice as long as the 2D-based procedure. Nonetheless, 3D-based measurement of orbital floor defects provides a more accurate estimation of the fracture area than the 2D-based procedure and can be helpful in determining the indication and planning the surgical procedure.

3D bioprinting of emulating homeostasis regulation for regenerative medicine applications

Homeostasis is the most fundamental mechanism of physiological processes, occurring simultaneously as the production and outcomes of pathological procedures. Accompanied by manufacture and maturation of intricate and highly hierarchical architecture obtained from 3D bioprinting (three-dimension bioprinting), homeostasis has substantially determined the quality of printed tissues and organs. Instead of only shape imitation that has been the remarkable advances, fabrication for functionality to make artificial tissues and organs that act as real ones in vivo has been accepted as the optimized strategy in 3D bioprinting for the next several years. Herein, this review aims to provide not only an overview of 3D bioprinting, but also the main strategies used for homeostasis bioprinting. This paper briefly introduces the principles of 3D bioprinting system applied in homeostasis regulations firstly, and then summarizes the specific strategies and potential trend of homeostasis regulations using multiple types of stimuli-response biomaterials to maintain auto regulation, specifically displaying a brilliant prospect in hormone regulation of homeostasis with the most recently outbreak of vasculature fabrication. Finally, we discuss challenges and future prospects of homeostasis fabrication based on 3D bioprinting in regenerative medicine, hoping to further inspire the development of functional fabrication in 3D bioprinting.

Nasoethmoid orbital fracture reconstruction using a three-dimensional printing-based craniofacial plate

The face is one of the most important parts of the body. Untreated facial fractures can result in deformities that can be harmful to patients. Three-dimensional (3D) printing is a rapidly evolving technology that has recently been widely applied in the medical field as it can potentially improve patient treatment. Although 3D printing technology is mostly used for craniofacial surgery, some studies have proved that it can be used to treat nasoethmoid orbital fractures. In this study, a patient-customized plate was constructed using a 3D printer and applied in a simulated surgery for the treatment of nasoethmoid orbital fracture.

Complications arising from clinical application of composite polycaprolactone/bioactive glass ceramic implants for craniofacial reconstruction: A prospective study

This study aimed to demonstrate the in vitro performance of a novel polymer-ceramic composite incorporating polycaprolactone (PCL) and bioactive glass (BGS-7), and investigate its clinical outcomes in craniofacial reconstruction. After preparation of the material, the biochemical properties of the composite PCL/BGS-7 implant were tested to evaluate apatite formation in simulated body fluid (SBF). Changes in the implant surface after soaking in the SBF were determined using field-emission scanning electron microscopy. For clinical application of the implant, patients with craniofacial defects were prospectively enrolled to receive three-dimensional (3D)-printed PCL/BGS-7 implants. Clinical outcomes were investigated by reviewing postoperative complications, including wound problems, allergic responses, hematoma, seroma, implant displacement, and bone union. The accuracy of reconstruction was assessed by measuring the surface error between the reconstructed and mirrored models. Upon exposure of the PCL/BGS-7 implant to SBF, apatite particles were actively developed on the surface of the PCL/BGS-7 sample, showing favorable bone-binding capacity. Regarding the clinical application, seven patients with craniofacial defects were included. The clinical outcome was favorable in terms of complications, except in one patient, who presented with delayed wound healing due to previous irradiation. The patients showed improvements in symmetry, with a significant change in mean ± SD surface error between preoperative (5 ± 3 mm) and postoperative (1.5 ± 0.65 mm) status (p = 0.018). Wthin the limitations of the study it seems that the PCL/BGS-7 implants might be a relevant option for repairing craniofacial bone defects, owing to its favorable bone-binding property and clinical safety, with few complications.

The Need for Innovation in Rhinoplasty

Rhinoplasty is a challenging surgery and results are not always perfect. There are many obstacles to achieving optimal results. Among these are inadequate instrumentation, the unpredictability of healing, imprecise planning, and many more. Furthermore, selecting patients who can most benefit from surgery is equally important. In this article, some of the more pressing areas of rhinoplasty that need innovation are discussed. From proper patient selection, to advances in education, to the standardization of training programs, to the development of sophisticated implants, the future of rhinoplasty surgery lies in continued creativity and innovation.

Tribo-corrosive behavior of additive manufactured parts for orthopaedic applications

Background

Additive manufacturing (AM) being an integral component of the production offers a wide variety of applications in the production of different components. The medical industry after the introduction of Additive Manufacturing has resulted in several advancements. The production of intricate patient-specific implants is one of such advancements which greatly assist a surgeon during a surgery. Orthopedic implants apart from possessing good mechanical strength are also expected to exhibit good tribological and corrosion behavior. As a result, the development of various orthopaedic implants and tools has become simple with the use of additive manufacturing.

Objectives and Rationale

In the current paper an effort has been made to discuss actual scientific knowledge on the tribo-corrosive behavior of additive manufactured parts for orthopedic applications. Different studies dealing with the mechanisms of lubrication and friction in synovial joints have also been considered. A special focus has also been laid down to study the corrosive effect of implants on the human body. A section dedicated to texturing of orthopedic implants has also been provided. The paper further elaborates the different research challenges and issues related to the use of additive manufacturing for the production of optimized orthopedic implants.

Conclusion

The study revealed that additive manufacturing has greatly aided in the manufacture of different orthopaedic implants with enhanced properties. However, a detailed study of the effect of processes like friction, wear, lubrication and corrosion in these implants needs to be done. The performance of these implants in the presence of various synovial fluids also needs to be addressed. However, the lack of more biocompatible materials, scalability and cost issues hinder the widespread use of AM in the different orthopaedic applications.

The Comparison of Clinical Efficacy of Minimally Invasive Tarsal Sinus Approach and L-Type Incision Approach Combined with 3D Printing Technology in Calcaneal Fracture

Purpose

To explore the comparison of the reduction of the subtalar articular surface and other postoperative effects of the minimally invasive tarsal sinus approach and lateral L-shaped incision conventional approach for the treatment of calcaneal fracture with 3D printing technology.

Methods

Patients who received surgical treatment for calcaneal fractures in the First Affiliated Hospital of Henan University of Science and Technology from June 2019 to December 2020 were collected. 3D printing equipment produced the affected side reduction heel bone fracture model and navigation template model. The tarsal sinus approach was used in the experimental group, and the lateral L-shaped incision approach was used in the control group. Patients were followed up 3 days, 1 month, 3 months, 6 months, and 12 months after the operation. Imaging indicators were measured 12 months after surgery, and scores from American Foot and Ankle Orthopaedic Society (AOFAS) and MSF were performed.

Results

Operation time was 70.52 ± 13.16 in the control group and 55.24 ± 12.25 minutes in the experimental group (P < 0.001). Intraoperative blood loss was 98.77 ± 18.65 in the control group and 89.56 + 17.54 in the experimental group (P > 0.05). The duration of antibiotic use was 5.53 ± 3.24 days in the control group and 5.48 ± 4.18 days in the experimental group (P > 0.05). The frequency of fluoroscopy was 6.56 ± 1.72 in the control group and 3.88 ± 1.05 in the experimental group (P < 0.001). Fracture healing time was 3.24 ± 0.52 months in the control group and 3.08 ± 0.58 months in the experimental group (P > 0.05). The postoperative Böhler angle was 28.31 ± 3.14 in the control group and 29.24 ± 2.76 in the experimental group (P > 0.05). Postoperative subtalar articular displacement (step > 2 mm) was observed in 4 patients in the control group and 1 in the experimental group (P < 0.05). MSF score was 90.12 ± 4.85 in the control group and 91.36 ± 2.58 in the experimental group (P > 0.05).

Conclusion

The study found that the experimental group was significantly better than the control group in terms of the operation time, intraoperative fluoroscopy times, and success rate of reduction of the subtalar articular surface. 3D printing technology can shorten the operation time, accurately reduce the fracture block, and reduce the secondary trauma, which is conducive to the functional recovery of the affected foot.

Mandibular Reconstruction With the Contralateral Vascularized Iliac Flap Using Individual Design: Iliac Crest Used to Reconstruct the Ramus and the Anterior Border of the Iliac Wing Used to Reconstruct the Inferior Border: A Case Report

Mandible defects resulting from resection of benign or malignant lesions, trauma, or radionecrosis are commonly encountered in the oral and maxillofacial department. Vascularized bone flaps, in general, provide the best functional and aesthetic outcome. The iliac crest provides a large piece of curved cortico-cancellous bone, measuring 6–16 cm in length. It has a natural curvature that complements the curve of the lateral and sometimes anterior mandible and can be placed accordingly to fill defects. In the paper, we report a mandibular reconstruction with a vascularized iliac flap using individual virtual preoperative planning and 3D printing technology. We want to offer a new design idea for mandibular defect reconstruction.

Optical scan and 3D printing guided radiation therapy - an application and provincial experience in cutaneous nasal carcinoma

Background

Single field Orthovoltage radiation is an acceptable modality used for the treatment of nasal cutaneous cancer. However, this technique has dosimetric pitfalls and unnecessary excessive exposure of radiation to organs at risk (OAR). We present the clinical outcome of a case series of cutaneous nasal tumours using a novel technique incorporating an optical scanner and a 3-dimensional (3D) printer to deliver treatments using parallel opposed (POP) fields.

Materials and methods

The POP delivery method was validated using ion chamber and phantom measurements before implementation. A retrospective chart review of 26 patients treated with this technique between 2015 and 2019 was conducted. Patients’ demographics and treatment outcomes were gathered and tabulated. These patients first underwent an optical scan of their faces to collect topographical data. The data were then transcribed into 3D printing algorithms, and positive impressions of the faces were printed. Custom nose block bolus was made with wax encased in an acrylic shell; 4 cm thick using the printed face models. Custom lead shielding was also generated. Treatments were delivered using 250 KeV photons POP arrangement with 4 cm diameter circle applicator cone and prescribed to the midplane. Dose and fractionation were as per physician discretion.

Results

Phantom measurements at mid-plane were found to match the prescribed dose within ±0.5%. For the 26 cases in this review, the median age was 78.5 years, with 15 females and 11 males. 85% of cases had Basal cell carcinoma (BCC); 1 had squamous cell carcinoma (SCC), one had synchronous BCC + SCC, and 1 had Merkel cell carcinoma. Twenty-one cases had T1N0 disease, 4 had T2N0, and 1 had T3N0. Dose and fractionation delivered were 40Gy in 10 fractions for the majority of cases. The complete response rate at a median follow-up of 6 months was 88%; 1 patient had a refractory tumour, and one patient had a recurrence. Toxicities were minor with 81% with no reported side effects. Three patients experienced grade 3 skin toxicity.

Conclusions

Utilization of optic scanner and 3D printing technology, with the innovative approach of using POP orthovoltage beams, allows an effective and efficient way of treatment carcinomas of the nose with a high control rate and low toxicity profiles.

Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations

Three-dimensional printing (3DP) has recently gained importance in the medical industry, especially in surgical specialties. It uses different techniques and materials based on patients' needs, which allows bioprofessionals to design and develop unique pieces using medical imaging provided by computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, the Department of Biology and Medicine and the Department of Physics and Engineering, at the Bioastronautics and Space Mechatronics Research Group, have managed and supervised an international cooperation study, in order to present a general review of the innovative surgical applications, focused on anatomical systems, such as the nervous and craniofacial system, cardiovascular system, digestive system, genitourinary system, and musculoskeletal system. Finally, the integration with augmented, mixed, virtual reality is analyzed to show the advantages of personalized treatments, taking into account the improvements for preoperative, intraoperative planning, and medical training. Also, this article explores the creation of devices and tools for space surgery to get better outcomes under changing gravity conditions.

Evolution of midface microvascular reconstruction: three decades of experience from a single institution

PURPOSE

Midface reconstruction poses a complex set of challenges for reconstructive surgeons. The optimal midface reconstruction must possess a durable underlying bone construct capable of integrating dental implants. Facial contour is restored by the overlying microvascular soft tissue reconstruction with reestablishment of the oral cavity. A plethora of microvascular flaps used in clinical practice have been described including those harvested from the iliac crest, scapula, fibula, forearm and back (latissimus dorsi). The objective was to share our experiences with each of these treatment options that have continued to evolve over time for the benefit of patients.

METHODS

Our institution has over three decades of experience in reconstructing complex midface defects and this article summarizes midface reconstruction from an evolutionary perspective (for type II, III and IV defect; Browns classification, Supplementary Table I). We broadly divide this into (i) flaps supplied by the subscapular system (ii) autologous reconstruction with titanium mesh and (iii) fibula microvascular flaps using 3D planning.

RESULTS

The advantages and disadvantages for each approach are discussed (Supplementary Table II).

CONCLUSION

In the future, it is expected that 3D planning coupled with rapid prototyping, intraoperative navigation and CT imaging will become standard procedural practice.

Accuracy of the Application of 3-Dimensional Printing Models in Orbital Blowout Fractures-A Preliminary Study

BACKGROUND

Application of 3-dimensional (3D) printing technology has grown in the medical field over the past 2 decades. In managing orbital blowout fractures, 3D printed models can be used as intraoperative navigators and could shorten the operational time by facilitating prebending or shaping of the mesh preoperatively. However, a comparison of the accuracy of computed tomography (CT) images and printed 3D models is lacking.

MATERIAL AND METHODS

This is a single-center retrospective study. Patients with unilateral orbital blowout fracture and signed up for customized 3D printing model were included. Reference points for the 2D distance were defined (intersupraorbital notch distance, transverse horizontal, sagittal vertical, and anteroposterior axes for orbital cavity) and measured directly on 3D printing models and on corresponding CT images. The difference and correlation analysis were conducted.

RESULTS

In total, 9 patients were reviewed from June 2017 to December 2020. The mean difference in the intersupraorbital notch measurement between the 2 modules was -0.14 mm (P = 0.67). The mean difference in the distance measured from the modules in the horizontal, vertical, and anteroposterior axes of the traumatic orbits was 0.06 mm (P = 0.85), -0.23 mm (P = 0.47), and 0.51 mm (P = 0.32), whereas that of the unaffected orbits was 0.16 mm (P = 0.44), 0.34 mm (P = 0.24), and 0.1 mm (P = 0.88), respectively. Although 2D parameter differences (<1 mm) between 3D printing models and CT images were discovered, they were not statistically significant.

CONCLUSIONS

Three-dimensional printing models showed high identity and correlation to CT image. Therefore, personalized models might be a reliable tool of virtual surgery or as a guide in realistic surgical scenarios for orbital blowout fractures.

Assessment of an Artificial Intelligence Mandibular Osteotomy Design System: A Retrospective Study

BACKGROUND

In this study, an AI osteotomy software was developed to design the presurgical plan of mandibular angle osteotomy, which is followed by the comparison between the software-designed presurgical plan and the traditional manual presurgical plan, thus assessing the practicability of applying the AI osteotomy software in clinical practices.

METHODS

(1) Develop an AI osteotomy software: design an algorithm based on convolutional neural networks capable of learning feature point and processing clustering segmentation; then, select 2296 cases of successful 3D mandibular angle osteotomy presurgical plans, followed by using those 2296 cases to train the deep learning algorithm; (2) compare the osteotomy presurgical plan of AI osteotomy software and that of manual: first step: randomly selecting 80 cases of typical female head 3D CTs, and designing those 80 cases by means of AI osteotomy software designing (group A) and manually designing (group B), respectively; second step: comparing several indexes of group A and those of group B, including the efficiency index (time from input original CT data to osteotomy presurgical plan output), the safety index (the minimum distance from the osteotomy plane to the mandibular canal), the symmetry indexes (bilateral difference of mandibular angle, mandibular ramus height and mandibular valgus angle) and aesthetic indexes (width ratio between middle and lower faces (M/L), mandibular angle and mandibular valgus angle).

RESULTS

The efficiency index: the design time of group A is 1.768 ± 0.768 min and that of group B is 26.108 ± 1.137 min, with P = 0.000; the safety index: The minimum distances from the osteotomy plane to the mandibular canal are 3.908 ± 0.361mm and 3.651 ± 0.437mm, p = 0.117 in groups A and B, respectively; The symmetry indexes: Bilateral differences of mandibular angle are 1.824 ± 1.834° and 1.567 ± 1.059° in groups A and B, respectively, with P = 0.278; bilateral differences of mandibular ramus height are 2.083 ± 1.263 and 2.965 ± 1.433, respectively, with P = 0.119 in groups A and B; Aesthetic indexes: M/L in groups A and B is 1.364 ± 0.074 and 1.371 ± 0.067, respectively, with P = 0.793; mandibular angles in groups A and B are 127.724 ± 5.800° and 127.242 ± 5.545°, respectively, with P = 0.681; Valgus angles in groups A and B are 11.474 ± 5.380 and 9.743 ± 4.620, respectively, with P = 0.273.

CONCLUSIONS

With high efficiency, as well as safety, symmetry and aesthetics equivalent to those of a manual design, the AI osteotomy software designing can be used as an alternative method for manual osteotomy designing.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The application of additive manufacturing / 3D printing in ergonomic aspects of product design: A systematic review

Additive Manufacturing (AM) facilitates product personalization and iterative design, which makes it an ideal technology for ergonomic product development. In this study, a systematic review was conducted of the literature regarding the use of AM in ergonomic-product design, and methodological aspects of the studies were analyzed. A literature search was performed using the keywords "3D print*," "additive manufacturing," "ergonomic*" and "human factors". Included were studies reporting the use of AM specifically in ergonomic design of products/prototypes including the detailing of an ergonomic testing methodology used for evaluation. Forty studies were identified pertaining to the fields of medicine, assistive technology, wearable technology, hand tools, testing devices and others. The most commonly used technology was fused deposition modeling with polylactic acid, but the overall preferred material was acrylonitrile butadiene styrene. Various combinations of objective/subjective and qualitative/quantitative product evaluation methods were used. Based on the findings, recommendations were developed to facilitate the choice of most suitable AM technologies and materials for specific applications in ergonomics.

Many Moving Pieces: Virtual Preoperative Surgical Planning for Traumatic Occlusal Splints

INTRO

Achieving anatomic reduction and re-establishing premorbid occlusion in patients with complex maxillomandibular fractures is challenging even for seasoned surgeons. Historically, surgeons have utilized occlusal splints to help establish occlusal relationships before fracture reduction and fixation. These acrylic splints are fabricated from dental impressions and require manual repositioning of tooth bearing segments along the fracture line to reapproximate premorbid occlusion. The process is laborious, requires a dental lab, and is less efficacious in edentulous patients or those with significantly comminuted fractures; as such it has largely fallen out of practice. Recently, with advances in virtual 3D modeling and printing, we demonstrate that occlusal splints can be designed from computed tomography scans, manipulated virtually, and printed without obtaining impressions from the patient.

METHODS/RESULTS

In our series of 3 patients with complex maxillomandibular fractures, occlusal splints were created by 1) obtaining maxillofacial computed tomography scans, 2) reducing the fractures virtually, and 3) using orthognathic virtual surgery software to create the splint. The time between planning and delivery of the splint was 4 to 7 days. These splints were successfully utilized to help establish premorbid occlusion in conjunction with maxillomandibular fixation and aided in expeditious intraoperative fracture reduction and fixation.

CONCLUSIONS

In the treatment of complex facial fractures, occlusal splints can be a useful adjunct in the operative reduction and fixation of fractures. With the advent of virtual preoperative surgical planning via 3D modeling and 3D printing, these occlusal splints can be created of a sufficient fidelity to avoid the strict need for dental impressions.

Role of Three-dimensional Printing in Neurosurgery: An Institutional Experience

Background:

Recent advancements in three-dimensional (3D) printing technology in the field of neurosurgery have given a newer modality of management for patients. In this article, we intend to share our institutional experience regarding the use of 3D printing in three modalities, namely, cranioplasty using customized 3D-printed molds of polymethylmethacrylate, 3D-printed model-assisted management of craniovertebral (CV) junction abnormalities, and 3D model-assisted management of brain tumors.

Materials and Methods:

A total of 55 patients were included in our study between March 2017 and December 2019 at S. M. S Medical College, Jaipur, India. 3D-printed models were prepared for cranioplasty in 30 cases, CV junction anomalies in 18 cases, and brain tumors in 7 cases. Preoperative and postoperative data were analyzed as per the diagnosis.

Results:

In cranioplasty, cranial contour and approximation of the margins were excellent and esthetic appearance improved in all patients. In CV junction anomalies, neck pain and myelopathy were improved in all patients, as analyzed using the visual analog scale and the Japanese Orthopedic Association Scale score, respectively. Our questionnaire survey revealed that 3D models for brain tumors were useful in understanding space interval and depth intraoperatively with added advantage of patient education.

Conclusion:

Rapid prototyping 3D-printing technologies provide a practical and anatomically accurate means to produce patient-specific and disease-specific models. These models allow for surgical planning, training, simulation, and devices for the assessment and treatment of neurosurgical disease. Expansion of this technology in neurosurgery will serve practitioners, trainees, and patients.

Benefits and Biosafety of Use of 3D-Printing Technology for Titanium Biomedical Implants: A Pilot Study in the Rabbit Model

BACKGROUND

Titanium has been used in osteosynthesis for decades and its compatibility and safety is unquestioned. Studies have shown that there is release and collection of titanium in the organ systems with little note of toxicity. The gold standard is considered to be titanium osteosynthesis plate produced by milling methods. The use of customized titanium plates produced with 3D printing, specifically direct metal laser sintering, have found increasing use in recent years. It is unknown how much titanium is released in these printed titanium implants, which is known to be potentially porous, depending on the heat settings of the printer. We hypothesize that the amount of titanium released in printed titanium implants may be potentially more or equal compared to the gold standard, which is the implant produced by milling.

METHODS

We studied the biosafety of this technology and its products by measuring serum and organ titanium levels after implantation of 3D-printed versus traditionally fabrication titanium plates and screws in a pilot study using the rabbit model. A total of nine rabbits were used, with three each in the control, milled and printed titanium group. The animals were euthanized after six months. Serum and organs of the reticuloendothelial system were harvested, digested and assayed for titanium levels.

RESULTS

Organ and serum titanium levels were significantly higher in rabbit subjects implanted with titanium implants (milled and printed) compared to the control group. However, there was no significant difference in organ and serum titanium levels of subjects implanted with milled and traditionally fabricated titanium implants.

CONCLUSIONS

The biosafety of use of 3D-printed titanium implants and traditionally fabricated titanium implants are comparable. With this in mind, 3D-printed custom implants can not only replace, but will very possibly surpass traditionally fabricated titanium implants in the mode and extent of use.

Application of Three-Dimensional Imaging in Asian Rhinoplasty with Costal Cartilage

BACKGROUND

3D computer-simulated technology is becoming popular in China. Rhinoplasty with costal cartilage is a good option for Asians. However, the application of 3D imaging in Asian rhinoplasty with costal cartilage has not been systematically assessed.

OBJECTIVE

To analyze the effect of 3D imaging in Asian rhinoplasty with costal cartilage.

METHODS

In this study, 44 patients were included and randomly divided into 3D and non-3D imaging groups. We performed a prospective survey on the aesthetic scores for preoperative, simulated, and postoperative images and calculated the relative nasal index scores of patients in both groups. Additionally, surveys on satisfactions with surgical outcomes and doctor-patient communication in both groups were conducted.

RESULTS

The actual postoperative result was well consistent with the preoperative simulation result. The 3D computer simulation did not impact the satisfaction with surgical outcomes but increased that with doctor-patient communication. The 3D computer-simulated technology was an effective tool for doctor-patient communication and surgery planning in Asian rhinoplasty with costal cartilage.

LEVEL OF EVIDENCE II

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Customized Surgical Protocols for Guided Bone Regeneration Using 3D Printing Technology: A Retrospective Clinical Trial

ABSTRACT

3D printing is one of the most significant technological advancements of the modern era. Among the various surgical disciplines, this new technology has shown significant improvements in the diagnosis and treatment of many diseases. The application of 3D printing has many benefits in training, preoperative planning and education.A retrospective study was conducted at the European University of Madrid (UEM). Patients were selected in this study using the following inclusion criteria: age over 18 years old, a preoperative cone beam computed tomography (CBCT), patients with moderate or severe vertical or horizontal defects, presence or absence of the tooth in the area to regenerate, no bone regeneration surgery before. Bone defects were measured: in the CBCT using White Fox Imaging, on the 3D printed model and then intraoperatively from the area to be regenerated. The average of the bone defects on the 3D measurements was statistically compared with the average of the bone defect measurements in the patient's mouth to evaluate the model reliability.The mean age of the patients was 53,07 years old, with a range from 45 to 63. Females were more affected than males, with a ratio of 12/13 (92%). The most frequent side affected was maxilla 10/13 (77%) and the most type of defect reported was horizontal 10/13 (77%). The means in width (x = 8,2923) and height (x = 6,9615) of the 3D model, were close and clinically acceptable if compared with the means obtained from the measurements in width (x = 7,9230) and height (x = 6,8076) of the patients' bone defects. None of the patients underwent further surgeries or needed intraoperative surgical corrections obtaining reliable results in terms of presurgical planning.It is possible to affirm that the use of 3D printed models can be a crucial complement when planning guided bone regeneration procedures, due to high reliability, and representing a turning point in many aspects of oral surgery.

[Anatomy of the deep circumflex iliac artery perforators and reconstruction of complex mandibular defects with chimeric deep circumflex iliac artery perforator flap]

OBJECTIVE

To investigate the anatomy of the perforator vessels of the deep circumflex iliac artery (DCIA) and the techniques for repairing mandibular complex defect using chimeric deep circumflex iliac artery perforator flap (DCIAPF).

OBJECTIVE

We analyzed the origin, distribution, number and courses of the perforator vessels of the DCIA, and measured the outside diameters of the vessels at the origin in 6 adult cadaveric specimens (12 sides) with latex perfusion. From July, 2018 to September, 2019, based on the results of anatomical study and imaging findings and using the digital surgical guide plate, we harvested DCIAPF from 4 patients for repairing mandibular body or angle defects and oral soft tissue defects.

OBJECTIVE

The perforating vessels of the DCIA included abdominal muscular branches, osteomusculocutaneous branches and terminal musculocutaneous branches. The abdominal muscle branches originated from the DCIA inguinal segment in 4 and from both the inguinal and iliac segments in 2 of the specimens. The osteomusculocutaneous branches all originated from the internal iliac crest in 75% and from both the inguinal and internal iliac crest segments in 25% of cases; the inguinal segment gave rise to only one perforating branch. The number of the musculocutaneous perforating branches was 1 (58.3%) or 2 (41.7%). In the 4 patients undergoing mandibular reconstruction, the DCIAPF survived in all cases with good recovery of the donor site wound. Satisfactory facial appearance with good oral morphology and occlusal relationship was achieved at 1 month postoperatively in all the patients. None of the patients experienced obvious functional abnormalities at the donor site, and imaging examination confirmed successful reconstruction of the oromandibular defects in all the cases.

OBJECTIVE

A good understanding of the anatomic characteristics of the perforator vessels of the DCIA combined with imaging examinations and digital surgery technology facilitates the harvest of DCIAPF for repairing mandibular body or angle defects complicated by oral soft tissue defects.

Osteogenesis of 3D-Printed PCL/TCP/bdECM Scaffold Using Adipose-Derived Stem Cells Aggregates; An Experimental Study in the Canine Mandible

Three-dimensional (3D) printing is perceived as an innovative tool for change in tissue engineering and regenerative medicine based on research outcomes on the development of artificial organs and tissues. With advances in such technology, research is underway into 3D-printed artificial scaffolds for tissue recovery and regeneration. In this study, we fabricated artificial scaffolds by coating bone demineralized and decellularized extracellular matrix (bdECM) onto existing 3D-printed polycaprolactone/tricalcium phosphate (PCL/TCP) to enhance osteoconductivity and osteoinductivity. After injecting adipose-derived stem cells (ADSCs) in an aggregate form found to be effective in previous studies, we examined the effects of the scaffold on ossification during mandibular reconstruction in beagle dogs. Ten beagles were divided into two groups: group A (PCL/TCP/bdECM + ADSC injection; n = 5) and group B (PCL/TCP/bdECM; n = 5). The results were analyzed four and eight weeks after intervention. Computed tomography (CT) findings showed that group A had more diffuse osteoblast tissue than group B. Evidence of infection or immune rejection was not detected following histological examination. Goldner trichrome (G/T) staining revealed rich ossification in scaffold pores. ColI, Osteocalcin, and Runx2 gene expressions were determined using real-time polymerase chain reaction. Group A showed greater expression of these genes. Through Western blotting, group A showed a greater expression of genes that encode ColI, Osteocalcin, and Runx2 proteins. In conclusion, intervention group A, in which the beagles received the additional ADSC injection together with the 3D-printed PCL/TCP coated with bdECM, showed improved mandibular ossification in and around the pores of the scaffold.

Method, Material, and Machine: A Review for the Surgeon Using Three-Dimensional Printing for Accelerated Device Production

BACKGROUND

Physicians are at the forefront of identifying innovative targets to address current medical needs. 3D printing technology has emerged as a state-of-the-art method of prototyping medical devices or producing patient-specific models that is more cost-efficient, with faster turnaround time, in comparison to traditional prototype manufacturing. However, initiating 3D printing projects can be daunting due to the engineering learning curve, including the number of methodologies, variables, and techniques for printing from which to choose. To help address these challenges, we sought to create a guide for physicians interested in venturing into 3D printing.

STUDY DESIGN

All commercially available, plug-and-play, material and stereolithography printers costing less than $15,000 were identified via web search. Companies were contacted to obtain quotes and information sheets for all printer models. The qualifying printers' manufacturer specification sheets were reviewed, and pertinent variables were extracted.

RESULTS

We reviewed 309 commercially available printers and materials and identified 118 printers appropriate for clinicians desiring plug-and-play models for accelerated device production. We synthesized this information into a decision-making tool to choose the appropriate parameters based on project goals.

CONCLUSIONS

There is a growing clinical need for medical devices to reduce costs of care and increase access to personalized treatments; however, the learning curve may be daunting for surgeons. In this review paper, we introduce the "3Ms of 3D printing" for medical professionals and provide tools and data sheets for selection of commercially available, affordable, plug-and-play 3D printers appropriate for surgeons interested in innovation.

Three-dimensional Printing in Plastic Surgery: Current Applications, Future Directions, and Ethical Implications

Background

Three-dimensional printing (3DP) is a rapidly advancing tool that has revolutionized plastic surgery. With ongoing research and development of new technology, surgeons can use 3DP for surgical planning, medical education, biological implants, and more. This literature review aims to summarize the currently published literature on 3DP's impact on plastic surgery.

Methods

A literature review was performed using Pubmed and MEDLINE from 2016 to 2020 by 2 independent authors. Keywords used for literature search included 3-dimensional (3D), three-dimensional printing (3DP), printing, plastic, surgery, applications, prostheses, implants, medical education, bioprinting, and preoperative planning. All studies from the database queries were eligible for inclusion. Studies not in English, not pertaining to plastic surgery and 3DP, or focused on animal data were excluded.

Results

In total, 373 articles were identified. Sixteen articles satisfied all inclusion and exclusion criteria, and were further analyzed by the authors. Most studies were either retrospective cohort studies, case reports, or case series and with 1 study being prospective in design.

Conclusions

3DP has consistently shown to be useful in the field of plastic surgery with improvements on multiple aspects, including the delivery of safe, effective methods of treating patients while improving patient satisfaction. Although the current technology may limit the ability of true bioprinting, research has shown safe and effective ways to incorporate biological material into the 3D printed scaffolds or implants. With an overwhelmingly positive outlook on 3DP and potential for more applications with updated technology, 3DP shall remain as an effective tool for the field of plastic surgery.

Multiscale sterilizable 3D printed auricular templates to guide cartilaginous framework sizing and sculpture during autologous microtia reconstruction

Microtia reconstruction using autologous costal cartilage can be one of the most challenging tasks in reconstructive surgery. An intraoperative guide using 2-dimentional drawing of the contralateral ear on an x-ray film remains the current standard of care. In this paper, we present the use of computer-aided design and desktop 3D printing to fabricate low cost, sterilizable auricular carving templates to serve as a peri-operative reference for microtia reconstruction. The design was made as a single component which incorporated the usual anatomic reference points of the ear based on Nagata technique as a Stereo-lithography file format (. STL) for 3D printing. The templates were created in sizes ranging from 55 mm to 70 mm with a 2 mm increment with an average production cost of 0.26 US dollars per material per template and about 4.5 US dollars for the whole set. Individual templates were then 3D-printed using a thermoplastic polyurethane (TPU 95A) semiflexible filament on a desktop fused deposition modeling, Ultimaker 2 + 3D printer. The produced template tolerated the sterilization process with no structural changes as compared to its pre-sterilization condition. In conclusion, we present cost-effective, sterilizable, multiscale auricular templates to guide the pre- and intra-operative carving of the cartilaginous framework during microtia reconstruction with more accuracy in a time efficient manner, thereby overcoming the drawbacks of using the traditional x-ray film. The templates are readily accessible and sharable for free through open-source software and can be directly 3D-printed using an affordable desktop 3D printer.

The effect of three-dimensional (3D) printing on quantitative and qualitative outcomes in paediatric orthopaedic osteotomies: a systematic review

Three-dimensional (3D) printing technology is increasingly being utilized in various surgical specialities. In paediatric orthopaedics it has been applied in the pre-operative and intra-operative stages, allowing complex deformities to be replicated and patient-specific instrumentation to be used. This systematic review analyses the literature on the effect of 3D printing on paediatric orthopaedic osteotomy outcomes.A systematic review of several databases was conducted according to PRISMA guidelines. Studies evaluating the use of 3D printing technology in orthopaedic osteotomy procedures in children (aged ≤ 16 years) were included. Spinal and bone tumour surgery were excluded. Data extracted included demographics, disease pathology, target bone, type of technology, imaging modality used, qualitative/quantitative outcomes and follow-up. Articles were further categorized as either 'pre-operative' or 'intra-operative' applications of the technology.Twenty-two articles fitting the inclusion criteria were included. The reported studies included 212 patients. There were five articles of level of evidence 3 and 17 level 4.A large variety of outcomes were reported with the most commonly used being operating time, fluoroscopic exposure and intra-operative blood loss.A significant difference in operative time, fluoroscopic exposure, blood loss and angular correction was found in the 'intra-operative' application group. No significant difference was found in the 'pre-operative' category.Despite a relatively low evidence base pool of studies, our aggregate data demonstrate a benefit of 3D printing technology in various deformity correction applications, especially when used in the 'intra-operative' setting. Further research including paediatric-specific core outcomes is required to determine the potential benefit of this novel addition. Cite this article: EFORT Open Rev 2021;6:130-138. DOI: 10.1302/2058-5241.6.200092.

3D Printed Biomimetic Rabbit Airway Simulation Model for Nasotracheal Intubation Training

Rabbit inhalation anesthesia by endotracheal intubation involves a higher risk among small animals owing to several anatomical and physiological features, which is pathognomonic to this species of lagomorphs. Rabbit-specific airway devices have been designed to prevent misguided intubation attempts. However, it is believed that expert anesthetic training could be a boon in limiting the aftermaths of this procedure. Our research is aimed to develop a novel biomimetic 3D printed rabbit airway model with representative biomechanical material behavior and radiodensity. Imaging data were collected for two sacrificed rabbit heads using micro-computed tomography (μCT) and micro-magnetic resonance imaging for the first head and cone beam computed tomography (CBCT) for the second head. Imaging-based life-size musculoskeletal airway models were printed using polyjet technology with a combination of hard and soft materials in replicates of three. The models were evaluated quantitatively for dimensional accuracy and radiodensity and qualitatively using digital microscopy and endoscopy for technical, tactic, and visual realism. The results displayed that simulation models printed with polyjet technology have an overall surface representation of 93% for μCT-based images and 97% for CBCT-based images within a range of 0.0-2.5 mm, with μCT showing a more detailed reproduction of the nasotracheal anatomy. Dimensional discrepancies can be caused due to inadequate support material removal and due to the limited reconstruction of microstructures from the imaging on the 3D printed model. The model showed a significant difference in radiodensities in hard and soft tissue regions. Endoscopic evaluation provided good visual and tactile feedback, comparable to the real animal. Overall, the model, being a practical low-cost simulator, comprehensively accelerates the learning curve of veterinary nasotracheal intubation and paves the way for 3D simulation-based image-guided interventional procedures.

Three-dimensional (3D) synthetic printing for the manufacture of non-biodegradable models, tools and implants used in surgery: a review of current methods

The advent of three-dimensional (3D) printing in the 1980s ushered in a new era of manufacturing. Original 3D printers were large, expensive and difficult to operate, but recent advances in 3D printer technologies have drastically increased the accessibility of these machines such that individual surgical departments can now afford their own 3D printers. As adoption of 3D printing technology has increased within the medical industry so too has the number of 3D printable materials. Selection of the appropriate printer and material for a given application can be a daunting task for any clinician. This review seeks to describe the benefits and drawbacks of different 3D printing technologies and the materials used therein. Commercially available printers using fused deposition modelling or fused filament fabrication technology and relatively inexpensive thermoplastic materials have enabled rapid manufacture of anatomic models and intraoperative tools as well as implant prototyping. Titanium alloys remain the gold-standard material for various implants used in the fixation of craniofacial or extremity fractures, but polymers and ceramics are showing increasing promise for these types of applications. An understanding of these materials and their compatibility with various 3D printers is essential for application of this technology in a healthcare setting.

Toward Biomimetic Scaffolds for Tissue Engineering: 3D Printing Techniques in Regenerative Medicine

Three-dimensional (3D) printing technology allows fabricating complex and precise structures by stacking materials layer by layer. The fabrication method has a strong potential in the regenerative medicine field to produce customizable and defect-fillable scaffolds for tissue regeneration. Plus, biocompatible materials, bioactive molecules, and cells can be printed together or separately to enhance scaffolds, which can save patients who suffer from shortage of transplantable organs. There are various 3D printing techniques that depend on the types of materials, or inks, used. Here, different types of organs (bone, cartilage, heart valve, liver, and skin) that are aided by 3D printed scaffolds and printing methods that are applied in the biomedical fields are reviewed.

Staged reconstruction of a chronically infected large skull defect using free tissue transfer and a patient-specific polyetheretherketone implant

Reconstructions of extensive composite scalp and cranial defects are challenging due to high incidence of postoperative infection and reconstruction failure. In such cases, cranial reconstruction and vascularized soft tissue coverage are required. However, optimal reconstruction timing and material for cranioplasty are not yet determined. Herein, we present a large skull defect with a chronically infected wound that was not improved by repeated debridement and antibiotic treatment for 3 months. It was successfully treated with anterolateral thigh (ALT) free flap transfer for wound salvage and delayed cranioplasty with a patient-specific polyetheretherketone implant. To reduce infection risk, we performed the cranioplasty 1 year after the infection had resolved. In the meantime, depression of ALT flap at the skull defect site was observed, and the midline shift to the contralateral side was reported in a brain computed tomography (CT) scan, but no evidence of neurologic deterioration was found. After the surgery, sufficient cerebral expansion without noticeable dead-space was confirmed in a follow-up CT scan, and there was no complication over the 1-year follow-up period.

Aplicaciones de la impresión 3D en cirugía plástica reconstructiva

La impresión 3D es una tecnología interesante en constante evolución. También conocida como manufactura aditiva, consiste en la conversión de diseños digitales a modelos físicos mediante la adición de capas sucesivas de material. En años recientes, y tras el vencimiento de múltiples patentes, diversos campos de las ciencias de la salud se han interesado en sus posibles usos, siendo la cirugía plástica una de las especialidades médicas que más ha aprovechado sus ventajas y aplicaciones, en especial la capacidad de crear dispositivos altamente personalizados a costos accesibles. Teniendo en cuenta lo anterior, el objetivo del presente artículo es describir los usos de la impresión 3D en cirugía plástica reconstructiva a partir de una revisión de la literatura.Las principales aplicaciones de la impresión 3D descritas en la literatura incluyen su capacidad para crear modelos anatómicos basados en estudios de imagen de pacientes, que a su vez permiten planificar procedimientos quirúrgicos, fabricar implantes y prótesis personalizadas, crear instrumental quirúrgico para usos específicos y usar biotintas en ingeniería tisular.La impresión 3D es una tecnología prometedora con el potencial de implementar cambios positivos en la práctica de la cirugía plástica reconstructiva en el corto y mediano plazo.

Simulation Surgery Using 3D 3-layer Models for Congenital Anomaly

We made realistic, three-dimensional, computer-assisted 3-layered elastic models of the face. The surface layer is made of polyurethane, the intermediate layer is silicone, and the deep layer is salt, representing the skin, subcutaneous tissue, and the bone. We have applied these 3-layer models to congenital anomaly cases and have understood that these models have a lot of advantages for simulation surgery.

Methods

We made 8 models. The models consisted of 2 models of 2 cases with Crouzon disease, 1 model of Binder syndrome, 1 model of facial cleft, 2 models of one case with Goldenhar syndrome, 1 model of cleft lip and palate, and 1 model of the hemifacial macrosomia.

Results

We could try several methods, could recognize whether the graft size is adequate, and could visualize the change of the facial contour. We could analyze how to approach the osteotomy line and actually perform osteotomy. The changes of the lower facial contour can be observed. We grafted the models of the graft and confirmed that the incisions could be closed well. We were able to visualize the change in the soft tissue contour by simulating distraction.

Conclusions

The most versatile merit of our models is that we could visualize the change of the soft tissue by movement of the hard tissue with bone graft, distraction osteogenesis, and so on. We must improve the model further to make it more realistic.

Three-Dimensional Diagnosis in Orbital Reconstructive Surgery

Introduction

Orbital floor fractures are common among mid-face fractures. The general aim of treatment is to restore orbital volume and anatomy with grafts or reconstructive materials. Malpositioning of the implants and inadequate volume restorations are common complications of these procedures. The aim of our study is to present the surgical outcomes of orbital reconstruction aided by our algorithm of patient-specific virtual planning.

Materials and Methods

The current study was performed on 77 patients with orbital wall fractures who were categorized into two groups: Group A - 42 patients (virtual planning) and Group B - 35 patients (traditional approach). Criteria of analysis included the presence of diplopia postoperatively and duration of surgical procedures.

Results

Diplopia was recorded right after surgery in 16 cases (38.1%) of Group A and in 12 cases (34.3%) of Group B. However, 6 months postreconstruction, residual diplopia was recorded in 4 cases (9.5%) of Group A and in 12 cases (34.3%) of Group B. Mean operation time in Group A for the patients with isolated zygoma fracture was 2.23 h; for isolated orbital wall fracture was 1.98 h; and for combined zygoma, orbital wall, and facial bone fracture was 3.07 h. In Group B, these indexes were 3.47, 2.05, and 3.31 h, respectively.

Conclusions

Application of virtual planning could significantly improve postoperative outcomes in orbital reconstruction. However, application of this technology could be limited by complicated defects of the orbital walls, which would require complex shape of the implant that might be difficult to be prevent virtually.

3D printing in pharmaceuticals: An emerging technology full of challenges

Although in its infancy, when compared with the other sectors, year 2005 marked the rapid evolution of 3 Dimensional printing (3DP) technologies in pharma sector with a huge potential in the dosage form designing and personalisation of the medication. 3DP is an innovative and highly promising way for the instant manufacturing in contrast with the tailored made conventional manufacturing. Various 3DP technologies are categorized into the various areas on the basis of the type of material used, deposition techniques and the solidification/fusion techniques. 3DP technologies have multiple pharmaceutical applications including formulation of the precise and unique dosage forms, medical research, personalization of medicine, tissues engineering and surgical application. In the present article, we have accentuated the comparative merits and demerits of various 3DP technologies used in the pharmaceutical sector. An insight in to the challenges, apropos availability and the choice of the excipients, as well as the printer, regulatory and safety concern of the product is provided.

Layer-by-Layer Printing of Photopolymers in 3D: How Weak is the Interface?

Additive manufacturing or, as also called, three-dimensional (3D) printing is considered as a game-changer in replacing traditional processing methods in numerous applications; yet, it has one intrinsic potential weakness related to bonding of layers formed during the printing process. Prior to finding solutions for improvement, a thorough quantitative understanding of the mechanical properties of the interface is needed. Here, a quantitative analysis of the nanomechanical properties in 3D printed photopolymers formed by digital light processing (DLP) stereolithography (SLA) is shown. Mapping of the contact Young's modulus across the layered structure is performed by atomic force microscopy (AFM) with a submicrometer resolution. The peakforce quantitative nanomechanical mapping (PF-QNM) mode was employed in the AFM experiments. The layered specimens were obtained from an acrylate-based resin (PR48, Autodesk), containing also a light-absorbing dye. We observed local depressions with values up to 30% of the maximum stiffness at the interface between the consecutively deposited layers, indicating local depletion of molecular cross-link density. The thickness values of the interfacial layers were approximately 11 μm, which corresponds to ∼22% of the total layer thickness (50 μm). We attribute this to heterogeneities of the photopolymerization reaction, related to (1) atmospheric oxygen inhibition and (2) molecular diffusion across the interface. Additionally, a pronounced stiffness decay was observed across each individual layer with a skewed profile. This behavior was rationalized by a spatial variation of the polymer cross-link density related to the variations of light absorption within the layers. This is caused by the presence of light absorbers in the printed material, resulting in a spatial decay of light intensity during photopolymerization.

Low-Cost Desktop-Based Three-Dimensional-Printed Patient-Specific Craniofacial Models in Surgical Counseling, Consent Taking, and Education of Parent of Craniosynostosis Patients: A Comparison With Conventional Visual Explanation Modalities

BACKGROUND

Craniosynostosis is a complex craniofacial deformity. Surgical decision, if needed, is always hard on the parent and requires the use of multimodalities of explanation. To the authors' knowledge, there have been no studies tackling family counseling about the deformity and surgical decision-making process with the use of low-cost patient-specific three-dimensional (3D)-printed models.

METHODS

A cross-sectional study investigating the utility of patient-specific 3D-printed models using a desktop-based 3D printer. Questionnaire was constructed and validated screening the demographics, knowledge, expectation, and surgical decision-making process supplied using Likert. Data were collected consecutively from each parent first after explanation with conventional 3D computed tomography (CT) images, and then repeated after the 3D-printed model has been presented.

RESULTS

Fourteen parents were screened. Majority of parents considered the pathology to have a potential effect of child's functional and aesthetic outcomes. After using the 3D-printed models, the participants had a clear vision and needed not to read any more about the condition (P = 0.05, P = 0.019, respectively). Agreement for surgical management was in favor of the 3D-printed models compared with CT images (P = 0.028). Explanation with CT images yielded higher mean score in knowledge about potential complications compared with 3D models (P value = 0.007). For the 3D models, average printing time was 26 hours, and a mean cost of 5.2$.

CONCLUSION

The utility of desktop 3D printing is an affordable modality to provide adequate information about craniosynostosis and can assist surgical decision-making. Knowledge and adaptation of such cheap technology represents a great skill aiding clinical practice.

The Use of a Three-Dimensional Printed Model for Surgical Excision of a Vascular Lesion in the Head and Neck

Facial vascular lesions are considered a great therapeutic challenge due to the considerable variability of clinical presentations. Surgical removal requires precise planning and advanced visualization to understand the three-dimensional anatomical relationships better.The aim of the study was to evaluate the feasibility of three-dimensional printed models, based on computed tomography angiography (CTA), in planning and guiding surgical excision of vascular lesions.A patient with a suspected vascular malformation in the face was recruited for participation in this feasibility study. Two personalized three-dimensional models were printed based off 2 separate CTA examinations. These constructs were used in preoperative planning and navigating surgical excision. The three-dimensional constructs identified the vicinity of the lesion and highlighted significant anatomical structures including the infraorbital nerve and vessels supplying the area of vascular anomaly. On postoperative follow-up the patient reported no recurrence of swelling and no sensory deficits.A personalized three-dimensional printed model of a facial vascular lesion was developed based on CTA images and used in preoperative planning and navigating surgical excision. It was most useful in establishing dangerous areas during the dissection process, including critical anatomical structures such as the infraorbital nerve. Combining conventional imaging techniques with three-dimensional printing may lead to improved diagnosis of vascular malformations and should be considered a useful adjunct to surgical management.

Three-dimensional printing in the preoperative planning of thoracoscopic pulmonary segmentectomy

Background

The purpose of this study is to explore whether 3D printing has a better clinical value for making a preoperative plan than three-dimensional computed tomography (3D-CT) in thoracoscopic pulmonary segmentectomy.

Methods

We collected a total of 124 patients' clinical data who underwent thoracoscopic pulmonary segmentectomy from October 2017 to August 2018. According to the preoperative examination, the patients were divided into three groups: general group, 3D-CT group, and 3D printing group. The clinical data of each group were analyzed and compared.

Results

Compared with the general group, intraoperative blood loss in 3D-CT group and 3D printing group decreased significantly (P<0.05). Operation time in 3D-CT group and 3D printing group was significantly shorter than in the general group (P<0.05). Between 3D-CT group and 3D printing group intraoperative blood loss and operation time had no significant differences (P>0.05). Postoperative chest tube duration and postoperative hospital stay had no significant differences between each group P>0.05). The incidence of postoperative hemoptysis in the general group occurred higher than in the 3D-CT group and 3D printing group, but the differences were not statistically significant (P>0.05). Postoperative complications of pneumonia, atelectasis, and pulmonary air leakage (>6 d) had no significant differences between each group (P>0.05).

Conclusions

3D printing and 3D-CT for making a preoperative plan have an equivalent effect in thoracoscopic pulmonary segmentectomy for experienced surgeons. Preoperative simulations using 3D printing for the assessment of pulmonary vessel and bronchi branching patterns is beneficial for the safe and efficient performance of thoracoscopic pulmonary segmentectomy.

Developing a 3D composite training model for cranial remodeling

OBJECTIVE

Craniosynostosis correction, including cranial vault remodeling, fronto-orbital advancement (FOA), and endoscopic suturectomy, requires practical experience with complex anatomy and tools. The infrequent exposure to complex neurosurgical procedures such as these during residency limits extraoperative training. Lack of cadaveric teaching tools given the pediatric nature of synostosis compounds this challenge. The authors sought to create lifelike 3D printed models based on actual cases of craniosynostosis in infants and incorporate them into a practical course for endoscopic and open correction. The authors hypothesized that this training tool would increase extraoperative facility and familiarity with cranial vault reconstruction to better prepare surgeons for in vivo procedures.

METHODS

The authors utilized representative craniosynostosis patient scans to create 3D printed models of the calvaria, soft tissues, and cranial contents. Two annual courses implementing these models were held, and surveys were completed by participants (n = 18, 5 attending physicians, 4 fellows, 9 residents) on the day of the course. These participants were surveyed during the course and 1 year later to assess the impact of this training tool. A comparable cohort of trainees who did not participate in the course (n = 11) was also surveyed at the time of the 1-year follow-up to assess their preparation and confidence with performing craniosynostosis surgeries.

RESULTS

An iterative process using multiple materials and the various printing parameters was used to create representative models. Participants performed all major surgical steps, and we quantified the fidelity and utility of the model through surveys. All attendees reported that the model was a valuable training tool for open reconstruction (n = 18/18 [100%]) and endoscopic suturectomy (n = 17/18 [94%]). In the first year, 83% of course participants (n = 14/17) agreed or strongly agreed that the skin and bone materials were realistic and appropriately detailed; the second year, 100% (n = 16/16) agreed or strongly agreed that the skin material was realistic and appropriately detailed, and 88% (n = 14/16) agreed or strongly agreed that the bone material was realistic and appropriately detailed. All participants responded that they would use the models for their own personal training and the training of residents and fellows in their programs.

CONCLUSIONS

The authors have developed realistic 3D printed models of craniosynostosis including soft tissues that allow for surgical practice simulation. The use of these models in surgical simulation provides a level of preparedness that exceeds what currently exists through traditional resident training experience. Employing practical modules using such models as part of a standardized resident curriculum is a logical evolution in neurosurgical education and training.

Accuracy of external measurements of 3-dimensional (3D) printed biomodels of the canine radius used in an in-hospital setting

The objective of this study was to determine if biomodels printed on a fused deposition modeling (FDM) device from computed tomography (CT) data are accurate by comparing external measurements to the native bone, considering that the clinical usefulness of the printed biomodels in an in-hospital setting depends on their verified accuracy and consistency. Using canine cadaveric radii previously stripped of all soft tissues, 7 parameters of the actual bone and the 3-dimensional (3D) printed biomodels were measured and compared to determine how accurately the models represent the cadaveric bone. A total of 28 canine radii were collected, in which the landmarks for measurements were established. Radiographs were then taken to determine the frontal center of rotation of angulation (CORA) and CT scans were carried out. Finally, a 3D virtual reconstruction was done and converted into a stereolithography (STL) format file, from which 2 biomodels were printed per bone. Measurements for biomodels were compared for equivalence to cadaveric measurements. For the 7 measured parameters, the mean difference between biomodel and cadaveric parameters ranged from an increase of +0.66% in cranial-caudal proximal (CrCdP)-CORA to a decrease of -1.32% in distal width of the radius. For all 7 measured parameters, measurements for biomodels were statistically equivalent to their corresponding cadaveric bone (P < 0.001). The 7 measured parameters in the 3D models printed with an FDM device were not significantly different than those in the original bone. In fact, these measurements closely approximated original bone measurements (within 1.5%); therefore, validating their application in future presurgical planning for various orthopedic procedures.

Temporal Hollowing Augmentation With Polyetheretherketone Patient-Specific Implant

Temporal hollowing is a common complication of surgical dissection in the temporal region. As it is a serious cosmetic problem, the need for reconstruction is increasing. Advances in medical imaging, computer software, 3-dimensional printing technology, and biochemistry have enabled surgeons to use patient-specific implants for correction of craniofacial deformities. Titanium, polymethylmethacrylate, and polyetheretherketone are representative materials of the alloplastic implant. In this article, the authors report the first case of temporal hollowing augmentation using a polyetheretherketone patient-specific implant.

3-DIEPrinting: 3D-printed Models to Assist the Intramuscular Dissection in Abdominally Based Microsurgical Breast Reconstruction

Supplemental Digital Content is available in the text.

Harvest of the deep inferior epigastric vessels for microsurgical breast reconstruction can be complicated by an intricate and lengthy subfascial dissection. Although multiple preoperative imaging modalities exist to help visualize the vascular anatomy and assist in perforator selection, few can help clearly define the intramuscular course of these vessels. The authors introduce their early experience with 3D-printed anatomical modeling (to-scale) of the infraumbilical course of the deep inferior epigastric subfascial vascular tree to better assist in executing the intramuscular dissection.