Low-Cost, Three-Dimensionally-Printed, Anatomical Models for Optimization of Orbital Wall Reconstruction

Rapid-printed Three-dimensional Models for Craniomaxillofacial Trauma

Background

Advances in surgical planning and 3-dimensional (3D) printing have benefitted the field of craniomaxillofacial surgery by allowing visualization of patient anatomy in settings of otherwise restricted surgical fields. Long 3D print times limit the usability of surgical planning workflows in acute trauma reconstruction. We sought to identify variables affecting print time and produce rapid-printed models with sufficient quality for prebending osteosynthesis plates.

Methods

Three-dimensional printing variables, including resolution, print orientation, and region of interest cropping, were optimized on a single mandibular and midface fracture model to maximize print time efficiency. Five mandibular and 5 midface fractures were printed both in the high-resolution and time-efficient protocol. Fixation plates were contoured to fit the optimized models and computed tomography scan. Distances and volumes between the fracture surface and plate were computed.

Results

High-resolution mandible models were printed in 7.47 hours and maxillae in 7.53 hours. Optimized models were printed in 0.93 and 1.07 hours, respectively. Cropping to regions of interest, rotating the model, and decreasing print resolution significantly reduced print time. The difference (optimized versus high resolution) in distance between the plate and model averaged 0.22 and 0.34 mm for mandibles and maxillae; the air space volume differed by 1.39 and 0.90 mm3, respectively.

Conclusions

Adjusting size, resolution, and position on the printing platform allows rapid fabrication of 3D models for surgical reconstruction without sacrificing surface quality. These edits reduce printing time, enabling the implementation of 3D-printing workflows for surgical planning in acute craniomaxillofacial trauma settings.

Advances in Three-Dimensional Printing for Craniomaxillofacial Trauma Reconstruction: A Systematic Review

Craniomaxillofacial (CMF) fractures present significant challenges for plastic surgeons due to their intricate nature. Conventional methods such as autologous bone grafts have limitations, necessitating advancements in reconstructive surgery techniques. This study reviewed the use of three-dimensional printing for CMF trauma reconstruction using human studies. A systematic search of PubMed, EMBASE, and Google Scholar was conducted in February 2024 for case reports, case series, and clinical trials related to CMF trauma reconstruction using three-dimensional printing technology. The authors' systematic review included 20 studies and a total of 170 participants with CMF bone defects. In general, the authors observed low bias risk in analyzed case reports and series, serious bias risk in nonrandomized controlled trials, and moderate bias risk in randomized controlled trials. The printed objects included CMF structure model prototypes, patient-specific implants, and other custom surgical devices. Studies reveal successful outcomes, including restored facial symmetry and function, restored orbital occlusion, resolved enophthalmos and diplopia, achieved cosmetically symmetrical lower face reconstruction, and precise fitting of surgical devices, enhancing patient and surgeon comfort. However, complications such as local infection, implant exposure, and persistent diplopia were reported. Three-dimensional printed devices reduced surgery time but increased preparation time and production costs. In-house production options could mitigate these time and cost expenditures. Three-dimensional printing holds potential in CMF trauma reconstruction, addressing both functional and esthetic restoration. Nevertheless, challenges persist in implementing this advanced technology in resource-limited environments.

Biomechanical analysis of fixation methods for bone flap repositioning after lateral orbitotomy approach: A finite element analysis

OBJECTIVE

In ophthalmic surgery, different materials and fixation methods are employed for bone flap repositioning after lateral orbitotomy approach (LOA), yet there is no unified standard. This study aims to investigate the impact of different fixation strategies on orbital stability through Finite Element Analysis (FEA) simulations of the biomechanical environment for orbital rim fixation in LOA.

METHODS

A Finite Element Model (FEM) was established and validated to simulate the mechanical responses under various loads in conventional lateral orbitotomy approach (CLOA) and deep lateral orbital decompression (DLOD) using single titanium plate, double titanium plates, and double absorbable plates fixation methods. The simulations were then validated against clinical cases.

RESULTS

Under similar conditions, the maximum equivalent stress (MES) on titanium alloy fixations was greater than that on absorbable plate materials. Both under static and physiological conditions, all FEM groups ensured structural stability of the system, with material stresses remaining within safe ranges. Compared to CLOA, DLOD, which involves the removal of the lateral orbital wall, altered stress conduction, resulting in an increase of MES and maximum total deformation (MTD) by 1.96 and 2.62 times, respectively. Under a horizontal load of 50 N, the MES in FEM/DLOD exceeded the material's own strength, with an increase in MES and MTD by 3.18 and 6.64 times, respectively, compared to FEM/CLOA. Under a vertical force of 50 N, the MES sustained by each FEM was within safe limits. Bone flap rotation angles remained minimally varied across scenarios. During follow-up, the 12 patients validated in this study did not experience complications related to the internal fixation devices.

CONCLUSION

Under static or physiological conditions, various fixation methods can effectively maintain stability at the orbitotomy site, and absorbable materials, with their smoother stress transmission properties, are more suited for application in CLOA. Among titanium plate fixations, single titanium plates can better withstand vertical stress, while double titanium plates are more capable of handling horizontal stress. Given the change in the orbital mechanical behavior due to DLOD, enhanced fixation strength should be considered for bone flap repositioning.

3D printing materials and 3D printed surgical devices in oral and maxillofacial surgery: design, workflow and effectiveness

Oral and maxillofacial surgery is a specialized surgical field devoted to diagnosing and managing conditions affecting the oral cavity, jaws, face and related structures. In recent years, the integration of 3D printing technology has revolutionized this field, offering a range of innovative surgical devices such as patient-specific implants, surgical guides, splints, bone models and regenerative scaffolds. In this comprehensive review, we primarily focus on examining the utility of 3D-printed surgical devices in the context of oral and maxillofacial surgery and evaluating their efficiency. Initially, we provide an insightful overview of commonly utilized 3D-printed surgical devices, discussing their innovations and clinical applications. Recognizing the pivotal role of materials, we give consideration to suitable biomaterials and printing technology of each device, while also introducing the emerging fields of regenerative scaffolds and bioprinting. Furthermore, we delve into the transformative impact of 3D-printed surgical devices within specific subdivisions of oral and maxillofacial surgery, placing particular emphasis on their rejuvenating effects in bone reconstruction, orthognathic surgery, temporomandibular joint treatment and other applications. Additionally, we elucidate how the integration of 3D printing technology has reshaped clinical workflows and influenced treatment outcomes in oral and maxillofacial surgery, providing updates on advancements in ensuring accuracy and cost-effectiveness in 3D printing-based procedures.

Presurgical Virtual Planning and Intraoperative Navigation with 3D-Preformed Mesh: A New Protocol for Primary Orbital Fracture Reconstruction

PURPOSE

This pilot study aims to evaluate the feasibility and effectiveness of computer-assisted surgery protocol with 3D-preformed orbital titanium mesh (3D-POTM), using presurgical virtual planning and intraoperative navigation in primary inferomedial orbital fracture reconstruction.

METHODS

Between March 2021 and March 2023, perioperative data of patients undergoing surgery for unilateral inferomedial orbital fracture treated with 3D-POTM were analyzed. Presurgical virtual planning with a Standard Triangle Language file of preformed mesh was conducted using the mirrored unaffected contralateral side as a reference, and intraoperative navigation was used. The reconstruction accuracy was determined by: correspondence between postoperative reconstruction mesh position with presurgical virtual planning and difference among the reconstructed and the unaffected orbital volume. Pre- and postoperative diplopia and enophthalmos were assessed.

RESULTS

Twenty-six patients were included. Isolated orbital floor fracture was reported in 14 (53.8%) patients, meanwhile medial wall and floor one in 12 (46.1%) cases. The mean difference between final plate position and ideal digital plan was 0.692 mm (95% CI: 0.601-0.783). The mean volume difference between reconstructed and unaffected orbit was 1.02 mL (95% CI: 0.451-1.589). Preoperative diplopia was settled out in all cases and enophthalmos in 19 (76.2%) of 21 patients.

CONCLUSION

The proposed protocol is an adaptable and reliable workflow for the early treatment of inferomedial orbital fractures. It enables precise preoperative planning and intraoperative procedures, mitigating pitfalls and complications, and delivering excellent reconstruction, all while maintaining reasonable costs and commitment times.

Delayed treatment of traumatic eyeball dislocation into the maxillary sinus and treatment algorithm: a case report and literature review

Orbital floor fractures are commonly encountered, but the dislocation of the eyeball into the maxillary sinus is relatively rare. When it does occur, globe dislocation can have serious consequences, including vision loss, enucleation, and orbito-ocular deformity. Immediate surgical intervention is typically attempted when possible. However, severe comorbidities and poor general health can delay necessary surgery. In this report, we present the surgical outcomes of a 70-year-old woman who received delayed treatment for traumatic eyeball dislocation into the maxillary sinus due to a subarachnoid hemorrhage and hemopneumothorax. Additionally, we propose a treatment algorithm based on our clinical experience and a review of the literature.

Orbitalization of Ethmoidal Sinus With Stacked Cross-linked Acellular Dermal Matrix: A New Strategy to Reconstruct Medial Orbital Wall Fracture

BACKGROUND

The use of an acellular dermal matrix (ADM) has not been reported in medial orbital wall fracture reconstruction previously. This study aimed to share our early experience with the cross-linked ADM as an allograft material for medial orbital wall reconstruction.

METHODS

In this study, the author evaluated the medical records and serial facial computed tomography scans of 27 patients with pure medial orbital wall fractures reconstructed by a single surgeon between May 2021 and March 2023. The author routinely approached the medial orbital wall with a retrocaruncular incision. Five out of 27 patients were reconstructed with trimmed, multiple folded, 1.0-mm-thick cross-linked ADM (MegaDerm; L&C Bio, South Korea).

RESULTS

All cases reconstructed with cross-linked ADM improved clinically and radiologically without complications. The serial computed tomography findings revealed that implanted cross-linked ADM successfully covered the defect while providing a significant volumizing effect.

CONCLUSIONS

This is the first study to show the efficacy of cross-linked ADM for orbital medial wall fracture reconstruction. Our strategy of orbitalization of ethmoidal sinus with stacked cross-linked ADM would be an excellent surgical option.

Automatic orbital segmentation using deep learning-based 2D U-net and accuracy evaluation: A retrospective study

The purpose of this study was to verify whether the accuracy of automatic segmentation (AS) of computed tomography (CT) images of fractured orbits using deep learning (DL) is sufficient for clinical application. In the surgery of orbital fractures, many methods have been reported to create a 3D anatomical model for use as a reference. However, because the orbit bone is thin and complex, creating a segmentation model for 3D printing is complicated and time-consuming. Here, the training of DL was performed using U-Net as the DL model, and the AS output was validated with Dice coefficients and average symmetry surface distance (ASSD). In addition, the AS output was 3D printed and evaluated for accuracy by four surgeons, each with over 15 years of clinical experience. One hundred twenty-five CT images were prepared, and manual orbital segmentation was performed in all cases. Ten orbital fracture cases were randomly selected as validation data, and the remaining 115 were set as training data. AS was successful in all cases, with good accuracy: Dice, 0.860 ± 0.033 (mean ± SD); ASSD, 0.713 ± 0.212 mm. In evaluating AS accuracy, the expert surgeons generally considered that it could be used for surgical support without further modification. The orbital AS algorithm developed using DL in this study is extremely accurate and can create 3D models rapidly at low cost, potentially enabling safer and more accurate surgeries.

The Usefulness of the Navigation System to Reconstruct Orbital Wall Fractures Involving Inferomedial Orbital Strut

BACKGROUND

Little attention has been paid to combined orbital floor and medial wall fractures with the involvement of the inferomedial orbital strut. Managing this particular fracture can prove challenging. However, various innovative techniques have been introduced to assist with the process. Our study focuses on sharing our approach to orbital wall reconstruction using navigation guidance and titanium-reinforced porous polyethylene plates, specifically cases involving the inferomedial orbital strut. We believe that implementing a navigation system can effectively lead surgeons to the fracture site with utmost safety. Also, we hypothesized that this navigation system is beneficial to use singe fan titanium-reinforced porous polyethylene plates with orbital wall fractures involving IOS while minimizing possible complications.

METHODS

We retrospectively reviewed 131 patients with medial orbital wall and orbital floor fractures with or without combined other facial bone fractures who underwent orbital wall reconstruction by a single surgeon from May 2021 to May 2023. Amongst, we identified fourteen orbital wall fractures involving the inferomedial orbital strut. We used a subciliary incision as the only approach method for performing titanium-reinforced porous polyethylene plates for navigation-guided orbital wall reconstruction. Patients were followed up for at least three months.

RESULTS

All cases were effectively resolved using titanium-reinforced porous polyethylene plates. There were no complications during the patient's complete recovery, confirmed clinically and radiologically. Based on the serial CT results, it was discovered that implanted titanium-reinforced porous polyethylene plates successfully covered the defect.

CONCLUSION

Based on our retrospective analysis, it has been determined that among the 131 recorded cases of orbital fractures, 14 of them (or 10.7%) involved the inferomedial orbital strut. Navigation-guided reduction using titanium-reinforced porous polyethylene (TR-PPE) plates can lead to predictable, reliable, and excellent outcomes for treating orbital fractures involving the inferomedial orbital strut without complications.

Printing in Time for Cranio-Maxillo-Facial Trauma Surgery: Key Parameters to Factor in

Study Design

retrospective cohort study.

Objective

3D printing is used extensively in cranio-maxillo-facial (CMF) surgery, but difficulties remain for surgeons to implement it in an acute trauma setting because critical information is often omitted from reports. Therefore, we developed an in-house printing pipeline for a variety of cranio-maxillo-facial fractures and characterized each step required to print a model in time for surgery.

Methods

All consecutive patients requiring in-house 3D printed models in a level 1 trauma center for acute trauma surgery between March and November 2019 were identified and analyzed.

Results

Sixteen patients requiring the printing of 25 in-house models were identified. Virtual Surgical Planning time ranged from 0h 08min to 4h 41min (mean = 1h 46min). The overall printing phase per model (pre-processing, printing, and post-processing) ranged from 2h 54min to 27h 24min (mean = 9h 19min). The overall success rate of prints was 84%. Filament cost was between $0.20 and $5.00 per model (mean = $1.56).

Conclusions

This study demonstrates that in-house 3D printing can be done reliably in a relatively short period of time, therefore allowing 3D printing usage for acute facial fracture treatment. When compared to outsourcing, in-house printing shortens the process by avoiding shipping delays and by having a better control over the printing process. For time-critical prints, other time-consuming steps need to be considered, such as virtual planning, pre-processing of 3D files, post-processing of prints, and print failure rate.

Effectiveness of Cross-Linked Acellular Dermal Matrix to Correct Post-Traumatic Enophthalmos

BACKGROUND

The use of an acellular dermal matrix is rarely reported in orbital wall fracture reconstruction. This study aimed to share the author's experience with the cross-linked acellular dermal matrix as an allograft material for enophthalmos correction.

METHODS

In this retrospective study, the author evaluated the medical records and 3-dimensional facial computed tomography scans of patients with enophthalmos caused by neglected orbital fractures between May 2021 and June 2022. Facial computed tomography scans confirmed the clinical diagnosis of enophthalmos. A single surgeon performed all surgical operations. In all patients, the author accessed the orbital floor via subciliary incision while approaching the medial wall with a retrocaruncular incision. After fully exposing the lesion, the author used a 1.0-mm-thick cross-linked acellular dermal matrix (ADM) (MegaDerm; L&C Bio, South Korea). After trimming the cross-linked ADM to a proper size, the author implanted the ADM into the lesion.

RESULTS

During May 2021 and June 2022, 3 cases of enophthalmos were successfully corrected with cross-linked ADM at the author's hospital. All patients were improved clinically and radiologically.

CONCLUSION

This is the first study to show the effectiveness of cross-linked ADM for the correction of enophthalmos.

Virtual Planning and 3D Printing in the Management of Acute Orbital Fractures and Post-Traumatic Deformities

Virtual surgical planning (VSP) and three-dimensional (3D) printing have advanced surgical reconstruction of orbital defects. Individualized 3D models of patients' orbital bony and soft tissues provide the surgeon with corrected orbital volume based on normalized anatomy, precise location of critical structures, and when needed a better visualization of the defect or altered anatomy that are paramount in preoperative planning. The use of 3D models preoperatively allows surgeons to improve the accuracy and safety of reconstruction, reduces intraoperative time, and most importantly lowers the rate of common postoperative complications, including over- or undercontouring of plates, orbital implant malposition, enophthalmos, and hypoglobus. As 3D printers and materials become more accessible and cheaper, the utility of printing patient-specific implants becomes more feasible. This article summarizes the traditional surgical management of orbital fractures and reviews advances in VSP and 3D printing in this field. It also discusses the use of in-house (point-of-care) VSP and 3D printing to further advance care of acute orbital trauma and posttraumatic deformities.

Point-of-Care Virtual Surgical Planning and 3D Printing in Oral and Cranio-Maxillofacial Surgery: A Narrative Review

This paper provides an overview on the use of virtual surgical planning (VSP) and point-of-care 3D printing (POC 3DP) in oral and cranio-maxillofacial (CMF) surgery based on a literature review. The authors searched PubMed, Web of Science, and Embase to find papers published between January 2015 and February 2022 in English, which describe human applications of POC 3DP in CMF surgery, resulting in 63 articles being included. The main review findings were as follows: most used clinical applications were anatomical models and cutting guides; production took place in-house or as "in-house-outsourced" workflows; the surgeon alone was involved in POC 3DP in 36 papers; the use of free versus paid planning software was balanced (50.72% vs. 49.27%); average planning time was 4.44 h; overall operating time decreased and outcomes were favorable, though evidence-based studies were limited; and finally, the heterogenous cost reports made a comprehensive financial analysis difficult. Overall, the development of in-house 3D printed devices supports CMF surgery, and encouraging results indicate that the technology has matured considerably.

Patient-specific Implants for Orbital Fractures: A Systematic Review

PURPOSE

Orbital fractures are common facial fractures that can be challenging to repair and require careful attention to avoid unacceptable ophthalmic complications. Customized implants that are unique to an individual patient, or patient-specific implants (PSIs), have been increasingly used to repair orbital wall fractures. This systematic review summarizes the current evidence regarding custom-made orbital wall implants.

METHODS

A keyword search of published literature from January 2010 to September 2021 was performed using Ovid MEDLINE, PubMed, and the Cochrane Library databases. Original articles that included more than 3 human subjects with an orbital fracture repaired with a PSI were included. The search results were reviewed, duplicates were removed and relevant articles were included for analysis.

RESULTS

Fifteen articles meeting the inclusion criteria. The articles were categorized into 3 separate groups based on the method of PSI fabrication: manual molding of a PSI on a 3D-printed orbital model (53%), directly from a 3D printer (27%), or via a template fabricated from a 3D printer (20%). Three primary postoperative outcomes were assessed: rates of diplopia, enophthalmos, and orbital volume. Postoperative rates of diplopia and enophthalmos improved regardless of the PSI technique, and postoperative orbital volumes were reduced compared with their preoperative state. When PSIs were compared to conventional implants, patient outcomes were comparable.

CONCLUSIONS

This review of existing PSI orbital implant literature highlights that while PSI can accurately and safely repair orbital fractures, patient outcomes are largely comparable to orbital fractures repaired by conventional methods, and PSI do not offer a definitive benefit over conventional implants.

Comparison of the decompressive effect of different surgical procedures for dysthyroid optic neuropathy using 3D printed models

PURPOSE

To compare the decompressive effect around the optic nerve canal among 3 different decompression procedures (medial, balanced, and inferomedial) using 3D printed models.

METHODS

In this experimental study, based on data obtained from 9 patients (18 sides) with dysthyroid optic neuropathy, a preoperative control model and 3 plaster decompression models were created using a 3D printer (total, 72 sides of 36 models). A pressure sensor was placed at the optic foramen, and the orbital space was filled with silicone. The surface of the silicone was pushed down directly, and changes in pressure were recorded at 2-mm increments of pushing.

RESULTS

At 10 mm of pushing, there was significantly lower pressure in the medial (19,782.2 ± 4319.9 Pa, P = 0.001), balanced (19,448.3 ± 3767.4 Pa, P = 0.003), and inferomedial (15,855.8 ± 4000.7 Pa, P < 0.001) decompression models than in the control model (25,217.8 ± 6087.5 Pa). Overall, the statistical results for each 2-mm push were similar among the models up to 10 mm of pushing (P < 0.050). At each push, inferomedial decompression caused the greatest reduction in pressure (P < 0.050), whereas there was no significant difference in pressure between the medial and balanced decompression models (P > 0.050).

CONCLUSION

All 3 commonly performed decompression procedures significantly reduced retrobulbar pressure. Because inferomedial decompression models obtained the greatest reduction in pressure on the optic nerve canal, inferomedial decompression should be considered the most reliable procedure for rescuing vision in dysthyroid optic neuropathy.

Differences in anthropometric measures of the orbit between Serbian and Roma populations of the Central Serbia

Introduction/Objectives. The shape and size of the orbital cavity are important parameters in planning surgical interventions and have significance in anthropology and forensic medicine. The aim of this study was to determine the morphometric characteristics of orbital cavity in Serbian population and to examine if there are differences in examined parameters between Serbs and the Roma Community of Serbia. Methods. Using computer tomography and subsequent multiplanar reconstruction we analyzed orbits from 76 Serbian and 18 Roma healthy volunteers. There was no significant difference in age between the ethnicities. Results. The height and width of the left orbit and the height of the right orbit were significantly higher in Roma group, whereas the width of the right orbit was not statistically different between ethnicities. Orbital indices, however, for both left and right orbit did not significantly differ between Serbian and Roma examinees. Right orbital volume did not differ between the groups, but left orbits had significantly larger volumes in Roma population. Finally, biorbital and interorbital width were both significantly higher in Roma than in Serbian examinees. We could not show differences between sexes except for the biorbital width, which had lower values in Serbian, but not Roma women than in men. Conclusion. Taken together, our results indicate larger orbits, as well as greater distances between the eyes in Roma than in Serbian examinees.

In-house 3D Model Printing for Acute Cranio-maxillo-facial Trauma Surgery: Process, Time, and Costs

Three-dimensional (3D) printing is used extensively in cranio-maxillo-facial (CMF) surgery, but its usage is limited in the setting of acute trauma specifically, as delays in outsourcing are too great. Therefore, we developed an in-house printing solution. The purpose of this study was to describe this process for surgeons treating acute CMF trauma. This series describes the printing process, time required, and printing material costs involved for in-house printing applied to a variety of acute CMF trauma cases involving the upper, middle, and lower thirds of the face and skull. All consecutive patients requiring in-house 3D printed models in a level 1 trauma center for acute trauma surgery in mid-2019 were identified and analyzed. Nine patients requiring the printing of 12 in-house models were identified. The overall printing time per model ranged from 2 hours, 36 minutes to 26 hours, 54 minutes (mean = 7h 55 min). Filament cost was between $0.20 and $2.65 per model (mean = $0.95). This study demonstrates that in-house 3D printing can be done in a relatively short period of time, therefore allowing 3D printing usage for various acute facial fracture treatments. The rapid improvements in the usability of 3D software and printing technology will likely contribute to further adoption of these technologies by CMF-trauma surgeons.

Establishing a point-of-care additive manufacturing workflow for clinical use

Additive manufacturing, or 3-Dimensional (3-D) Printing, is built with technology that utilizes layering techniques to build 3-D structures. Today, its use in medicine includes tissue and organ engineering, creation of prosthetics, the manufacturing of anatomical models for preoperative planning, education with high-fidelity simulations, and the production of surgical guides. Traditionally, these 3-D prints have been manufactured by commercial vendors. However, there are various limitations in the adaptability of these vendors to program-specific needs. Therefore, the implementation of a point-of-care in-house 3-D modeling and printing workflow that allows for customization of 3-D model production is desired. In this manuscript, we detail the process of additive manufacturing within the scope of medicine, focusing on the individual components to create a centralized in-house point-of-care manufacturing workflow. Finally, we highlight a myriad of clinical examples to demonstrate the impact that additive manufacturing brings to the field of medicine.