Three-Dimensional Printing: Custom-Made Implants for Craniomaxillofacial Reconstructive Surgery

Adoption of additive manufacturing in oral and maxillofacial surgery among university and non-university hospitals in Sweden: findings from a nationwide survey

PURPOSE

Additive manufacturing (AM) is an innovative printing technology that can manufacture 3-dimensional solid objects by adding layers of material from model data. AM in oral and maxillofacial surgery (OMFS) provides several clinical applications such as surgical guides and implants. However, the adoption of AM in OMFS is not well covered. The purpose was to study the adoption of AM in OMFS in university and non-university hospitals in Sweden. Three research questions were addressed: What is the degree of using AM solutions in university and non-university hospitals?; What are AM solutions used?; How are the AM solutions accessed (production mode) in university hospitals and non-university hospitals?

METHODS

A survey was distributed to OMF surgeons in Sweden. The questionnaire consisted of 16 questions. Data were analyzed through descriptive and content analysis.

RESULTS

A total of 14 university and non-university hospitals were captured. All 14 hospitals have adopted AM technology and 11 of the hospitals adopted AM in OMFS. Orthognathic and trauma surgery are two major types of surgery that involve AM technology where material extrusion and vat polymerization are the two most used AM technologies in OMFS. The primary application of AM was in medical models and guides.

CONCLUSION

Majority of Swedish university hospitals and non-university hospitals have adopted AM in OMFS. The type of hospital (university or non-university hospital) has no impact on AM adoption. AM in OMFS in Sweden can be perceived to be a mature clinical application.

Biofabrication methods for reconstructing extracellular matrix mimetics

In the human body, almost all cells interact with extracellular matrices (ECMs), which have tissue and organ-specific compositions and architectures. These ECMs not only function as cellular scaffolds, providing structural support, but also play a crucial role in dynamically regulating various cellular functions. This comprehensive review delves into the examination of biofabrication strategies used to develop bioactive materials that accurately mimic one or more biophysical and biochemical properties of ECMs. We discuss the potential integration of these ECM-mimics into a range of physiological and pathological in vitro models, enhancing our understanding of cellular behavior and tissue organization. Lastly, we propose future research directions for ECM-mimics in the context of tissue engineering and organ-on-a-chip applications, offering potential advancements in therapeutic approaches and improved patient outcomes.

Virtual surgical planning in craniomaxillofacial surgery: a structured review

Craniomaxillofacial (CMF) surgery is a challenging and very demanding field that involves the treatment of congenital and acquired conditions of the face and head. Due to the complexity of the head and facial region, various tools and techniques were developed and utilized to aid surgical procedures and optimize results. Virtual Surgical Planning (VSP) has revolutionized the way craniomaxillofacial surgeries are planned and executed. It uses 3D imaging computer software to visualize and simulate a surgical procedure. Numerous studies were published on the usage of VSP in craniomaxillofacial surgery. However, the researchers found inconsistency in the previous literature which prompted the development of this review. This paper aims to provide a comprehensive review of the findings of the studies by conducting an integrated approach to synthesize the literature related to the use of VSP in craniomaxillofacial surgery. Twenty-nine related articles were selected as a sample and synthesized thoroughly. These papers were grouped assigning to the four subdisciplines of craniomaxillofacial surgery: orthognathic surgery, reconstructive surgery, trauma surgery and implant surgery. The following variables - treatment time, the accuracy of VSP, clinical outcome, cost, and cost-effectiveness - were also examined. Results revealed that VSP offers advantages in craniomaxillofacial surgery over the traditional method in terms of duration, predictability and clinical outcomes. However, the cost aspect was not discussed in most papers. This structured literature review will thus provide current findings and trends and recommendations for future research on the usage of VSP in craniomaxillofacial surgery.

Patient-Specific Implants for Correction of Midfacial Aging

The nasolabial folds (NLFs) may be shallowed with the use of nostril base augmentation. This study aimed to design and customize patient-specific implants (PSIs) with computer-aided design/computer-aided manufacturing (CAD/CAM) to correct NLF deepening caused by midfacial aging. The patient's head computed tomography data obtained and were used for reconstruction. The PSIs were customized by CAD/CAM techniques, which were implanted into a nasal base for shallow NLFs caused by midfacial aging. Preoperative and postoperative photos and a wrinkle severity rating scale were used to evaluate the changes in NLFs. Also, the global esthetic improvement scale was used to investigate the surgical satisfaction of patients. Eleven patients (22 NLFs) received PSIs in the nasal base (22 implants). The customized PSI matched well with premaxilla, reducing the difficulty of operation. After 3 to 12 months of follow-up, PSI was stable without foreign body reaction or inflammatory reaction. Postoperative wrinkle severity rating scale scores showed that NLF severity was reduced in all patients, with a significant esthetic improvement compared with preoperatively ( P < 0.01). The global esthetic improvement scale showed an extremely satisfied improved NLF in 27.27% of patients, much improved in 63.63%, and improved in 9.90% (2/22), and none reported change or poor NLF. Patient satisfaction with their midface appearance differed significantly before and after surgery ( P < 0.01). Individualized PSI designed with high precision and matching degree by CAD and prepared using CAM could be applied to overcome the limitations of noncustomized implants.

The Use of Patient-Specific Orbital Reconstruction Implants During Maxillectomy Reconstruction

Background: Reconstruction of the orbital floor after maxillectomy can result in significant functional and aesthetic morbidity. Study Objective: To measure eyelid position, self-reported visual outcomes, and complications in patients undergoing concurrent maxillectomy and reconstruction with a patient-specific orbital reconstruction implant (PSORI). Design Type: Case series. Materials and Methods: Case series including 12 patients who received PSORI for orbital floor reconstruction after tumor extirpation. Primary outcomes gathered were diplopia, ectropion, and wound healing complications. Results: The majority of patients were men (75%) and the mean age was 53.3 years. Ten patients underwent free flap reconstruction with the majority receiving fibula free flaps (n = 6). Median follow-up was 415.5 days. Three patients (25%) experienced long-term complications, including diplopia (n = 1) and hardware extrusion (n = 3). Each of these occurred in the context of total maxillectomy and radiation. This prompted subsequent use of a modified implant design for the final six patients and the preferential use of a midface-degloving approach. These interventions eliminated extrusions in subsequent patients. Conclusion: PSORIs can be used for orbital floor reconstruction following maxillectomy in combination with free tissue transfer. Implant design is critical to reduce complications. The use of a midface degloving approach and a modified low-profile design was associated with a low rate of complications.

Three-dimensional Medical Printing and Associated Legal Issues in Plastic Surgery: A Scoping Review

Three-dimensional printing (3DP) represents an emerging field of surgery. 3DP can facilitate the plastic surgeon's workflow, including preoperative planning, intraoperative assistance, and postoperative follow-up. The broad clinical application spectrum stands in contrast to the paucity of research on the legal framework of 3DP. This imbalance poses a potential risk for medical malpractice lawsuits. To address this knowledge gap, we aimed to summarize the current body of legal literature on medical 3DP in the US legal system. By combining the promising clinical use of 3DP with its current legal regulations, plastic surgeons can enhance patient safety and outcomes.

Value of 3D printing technology combined with indocyanine green fluorescent navigation in complex laparoscopic hepatectomy

Background

Laparoscopic hepatectomy (LH) has achieved rapid progress over the last decade. However, it is still challenging to apply laparoscopy to lesions located in segments I, VII, VIII, and IVa and the hepatic hilar region due to difficulty operating around complex anatomical structures. In this study, we applied three-dimensional printing (3DP) and indocyanine green (ICG) fluorescence imaging technology to complex laparoscopic hepatectomy (CLH) to explore the effects and value of the modified procedure.

Materials and methods

From January 2019 to January 2021, 54 patients with complex hepatobiliary diseases underwent LH at our center. Clinical data were collected from these patients and retrospectively analyzed.

Results

A total of 30 patients underwent CLH using the conventional approach, whereas 24 cases received CLH with 3DP technology and ICG fluorescent navigation. Preoperative data were compared between the two groups. In the 3DP group, we modified the surgical strategy of four patients (4/24, 16.7%) due to real-time intraoperative navigation with 3DP and ICG fluorescent imaging technology. We did not modify the surgical strategy for any patient in the non-3DP group (P = 0.02). There were no significant differences between the non-3DP and 3DP groups regarding operating time (297.7±104.1 min vs. 328.8±110.9 min, P = 0.15), estimated blood loss (400±263.8 ml vs. 345.8±356.1 ml, P = 0.52), rate of conversion to laparotomy (3/30 vs. 2/24, P = 0.79), or pathological outcomes including the incidence of microscopical R0 margins (28/30 vs. 24/24, P = 0.57). Additionally, there were no significant differences in postoperative complications or recovery conditions between the two groups. No instances of 30- or 90-day mortality were observed.

Conclusion

The optimal surgical strategy for CLH can be chosen with the help of 3DP technology and ICG fluorescent navigation. This modified procedure is both safe and effective, but without improvement of intraoperative and short-term outcomes.

Facial defects reconstruction by titanium mesh bending using 3D printing technology: A report of two cases

Introduction

Facial injuries and deformities have received special attention during the previous decades for their functional, esthetic impairment, surgical challenges related to the location of the intervention, and their relationship to a lower survival rate. Moreover, there have been many surgical reconstructive methods due to the different materials and tools available and thus the final results following the surgical intervention.

Case presentation

This study was conducted on two patients with severe war injuries; they both suffered from a significant loss in one or more of the following bones: the zygomatic bone, maxilla, nasal bone, infraorbital rim, and mandible. They were treated using preshaped 3D titanium mesh implants that were made using polylactic acid (PLA) material. The final shape was identified depending on pregenerated multislice 3D modeling using computed tomography (CT) scan.

Clinical discussion and conclusion

The patient-specific titanium implants produced using polylactic acid (PLA) have been an important option for reconstructive surgical interventions in facial injuries. It has achieved a better outcome in comparison with manual bent titanium mesh in terms of anatomical symmetry, overall operating time, functional and esthetic impairment. These points helped achieve better care for both civilian and war injuries associated with bone loss.

•

Facial injuries are of significant consideration especially during war time.

•

Using titanium plates has increased due to its biocompatibility and rigid fixation.

•

A printing model for the skull using polylactic acid is a successful approach.

•

Pre-shaped mesh plates reveal better surgical outcomes.

Custom 3D-printed Titanium Implant for Reconstruction of a Composite Chest and Abdominal Wall Defect

Background

Three-dimensional (3D) printing of implantable materials is a recent technological advance that is available for clinical application. The most common medical application of 3D printing in plastic surgery is in the field of craniomaxillofacial surgery. There have been few applications of this technology in other areas.

Methods

Here, we discuss a case of a large, symptomatic composite thoracic and abdominal defect resulting from the resection of a chondrosarcoma of the costal marginand sections of the abdominal wall, diaphragm, and sternum. The initial and second attempts at reconstruction failed, resulting in a massive hernia. Given the size of the defect, the contiguity with a large abdominal wall defect, and the high risk of recurrence, a rigid thoracic reconstruction was essential to durably repair the thoracic hernia and serve as a scaffold to which both the diaphragm and the abdominal mesh could be secured. A custom-made plate offered the most durable and anatomically accurate reconstruction in this particular clinical scenario. This technology was used in concert with a single section of coated mesh for reconstruction of the diaphragm, chest wall, and abdominal wall.

Results

There were no post-operative complications. The patient has improvement of his symptoms and increased functional capacity. There is no evidence of hernia recurrence 1.5 years after repair.

Conclusions

3D printing technology proved to be a useful and effective application for reconstruction of this large thoracic defect involving the costal margin. It is an available technology that should be considered for reconstruction of rigid structures with defect-specific precision.

Procedure Increasing the Accuracy of Modelling and the Manufacturing of Surgical Templates with the Use of 3D Printing Techniques, Applied in Planning the Procedures of Reconstruction of the Mandible

The application of anatomical models and surgical templates in maxillofacial surgery allows, among other benefits, the increase of precision and the shortening of the operation time. Insufficiently precise anastomosis of the broken parts of the mandible may adversely affect the functioning of this organ. Applying the modern mechanical engineering methods, including computer-aided design methods (CAD), reverse engineering (RE), and rapid prototyping (RP), a procedure used to shorten the data processing time and increase the accuracy of modelling anatomical structures and the surgical templates with the use of 3D printing techniques was developed. The basis for developing and testing this procedure was the medical imaging data DICOM of patients treated at the Maxillofacial Surgery Clinic of the Fryderyk Chopin Provincial Clinical Hospital in Rzeszów. The patients were operated on because of malignant tumours of the floor of the oral cavity and the necrosis of the mandibular corpus, requiring an extensive resection of the soft tissues and resection of the mandible. Familiarity with and the implementation of the developed procedure allowed doctors to plan the operation precisely and prepare the surgical templates and tools in terms of the expected accuracy of the procedures. The models obtained based on this procedure shortened the operation time and increased the accuracy of performance, which accelerated the patient’s rehabilitation in the further course of events.

3D Printing of Physical Organ Models: Recent Developments and Challenges

Physical organ models are the objects that replicate the patient-specific anatomy and have played important roles in modern medical diagnosis and disease treatment. 3D printing, as a powerful multi-function manufacturing technology, breaks the limitations of traditional methods and provides a great potential for manufacturing organ models. However, the clinical application of organ model is still in small scale, facing the challenges including high cost, poor mimicking performance and insufficient accuracy. In this review, the mainstream 3D printing technologies are introduced, and the existing manufacturing methods are divided into "directly printing" and "indirectly printing", with an emphasis on choosing suitable techniques and materials. This review also summarizes the ideas to address these challenges and focuses on three points: 1) what are the characteristics and requirements of organ models in different application scenarios, 2) how to choose the suitable 3D printing methods and materials according to different application categories, and 3) how to reduce the cost of organ models and make the process simple and convenient. Moreover, the state-of-the-art in organ models are summarized and the contribution of 3D printed organ models to various surgical procedures is highlighted. Finally, current limitations, evaluation criteria and future perspectives for this emerging area are discussed.

Simplifying Bony Midface Reconstruction with Patient-specific Titanium Plates

Virtual surgical planning and patient-specific osteosynthesis plates provide reconstructive surgeons with the ability to proceed with facial reconstruction of expanding complexity. Moreover, these advances have been shown to reduce the energy, effort, and operating time while helping guide the surgeon toward anatomically correct results. The currently available literature regarding custom-milled plates pertains mostly to reconstructive surgery of the mandible. This small 3-patient series illustrates the use of patient-specific titanium plating to simplify complex reconstruction of the midface. Composite defects requiring multiple bony and soft tissue segments are difficult to reconstruct intraoperatively without prior planning. Custom plates and associated cutting guides based on patient-specific anatomy allow for a more streamlined, stepwise protocol for assembly of intricate constructs. Custom-manufactured hardware will precisely fit bony contours and minimize additional manipulation of both the bone and plate, maximally preserving internal strength and allowing for improved stability, dental occlusion, and spatial positioning. In addition to these mechanical benefits, the ease of mind and overall cost reduction through a reduction in procedural time are significant advantages offered by pre-designed plates. We hope that this series illustrates the value of custom-printed plates for midface reconstruction.

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.

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.

Identifying a commercially-available 3D printing process that minimizes model distortion after annealing and autoclaving and the effect of steam sterilization on mechanical strength

BACKGROUND

Fused deposition modeling 3D printing is used in medicine for diverse purposes such as creating patient-specific anatomical models and surgical instruments. For use in the sterile surgical field, it is necessary to understand the mechanical behavior of these prints across 3D printing materials and after autoclaving. It has been previously understood that steam sterilization weakens polylactic acid, however, annealing heat treatment of polylactic acid increases its crystallinity and mechanical strength. We aim to identify an optimal and commercially available 3D printing process that minimizes distortion after annealing and autoclaving and to quantify mechanical strength after these interventions.

METHODS

Thirty millimeters cubes with four different infill geometries were 3D printed and subjected to hot water-bath annealing then immediate autoclaving. Seven commercially available 3D printing materials were tested to understand their mechanical behavior after intervention. The dimensions in the X, Y, and Z axes were measured before and after annealing, and again after subsequent autoclaving. Standard and strength-optimized Army-Navy retractor designs were printed using the 3D printing material and infill geometry that deformed the least. These retractors were subjected to annealing and autoclaving interventions and tested for differences in mechanical strength.

RESULTS

For both the annealing and subsequent autoclaving intervention, the material and infill geometry that deformed the least, respectively, was Essentium PLA Gray and "grid". Standard retractors without intervention failed at 95 N +/- 2.4 N. Annealed retractors failed at 127.3 N +/- 10 N. Autoclave only retractors failed at 15.7 N +/- 1.4 N. Annealed then autoclaved retractors failed at 19.8 N +/- 3.1 N. Strength-optimized retractors, after the annealing then autoclaving intervention, failed at 164.8 N +/- 12.5 N.

CONCLUSION

For 30 mm cubes, the 3D printing material and infill geometry that deformed the least, respectively, was Essentium PLA and "grid". Hot water-bath annealing results in increased 3D printed model strength, however autoclaving 3D prints markedly diminishes strength. Strength-optimized 3D printed PLA Army-Navy retractors overcome the strength limitation due to autoclaving.

Fabrication of Naftopidil-Loaded Tablets Using a Semisolid Extrusion-Type 3D Printer and the Characteristics of the Printed Hydrogel and Resulting Tablets

The production of three-dimensional (3D)-printed drugs holds promise for future personalized medicine. Here, we prepared tablets containing naftopidil as a model drug using a semisolid extrusion-type 3D bioprinter applicable for tissue engineering. A hydrogel is typically used as the printer ink for 3D bioprinters, and we incorporated various amounts of hydroxypropyl methylcellulose hydrogel (30%, 40%, and 50% gel) into the printer ink. The resulting 3D-printed gel product was dried to obtain tablets. The rheological properties of the printer ink changed as its composition was changed, and tablets were prepared successfully from several formulations. Increasing the amount of hydroxypropyl methylcellulose hydrogel in the printer ink led to delayed drug dissolution, decreased weight, and decreased hardness of the tablets. Delayed drug dissolution was also observed when the amount of disintegrating agent typically used in powder compression tablets was increased in the ink, and increasing the incorporated amount of the disintegrating agent crospovidone increased the hardness of the tablets. Our results will provide useful information for the preparation of tablets using semisolid extrusion-type 3D printers.