A prospective multicenter study to compare the precision of posttraumatic internal orbital reconstruction with standard preformed and individualized orbital implants

Utilization of Computer-Assisted Navigation Technology Within Craniomaxillofacial Fracture Surgery: A Systematic Review

BACKGROUND

Use of intraoperative computer-assisted navigation (iCAN) has been well-established in otolaryngology and neurosurgery; however, its use in surgical management of facial fractures is yet to be reported on a large scale. This study aimed to review the existing literature to determine the outcomes, limitations, risks, and benefits of iCAN use in facial fracture management.

METHODS

A systematic review of iCAN use in craniomaxillofacial fracture surgery was performed by 2 authors in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search was conducted on 3 databases, PubMed, Cochrane Library, and Embase, using the search terms "navigation," "intraoperative," and "brain lab" in combination with "facial fractures" or "facial reconstruction." Study type, demographics, fracture characteristics, surgery characteristics, iCAN devices, intraoperative fracture fixation accuracy, postoperative outcomes, complications, navigation limitations, and risks and benefits were analyzed.

RESULTS

There were 909 studies identified in the initial search, of which 42 were chosen for final use. iCAN use was most commonly reported in unilateral (57.1%) and complex (50%) facial fracture cases. Surgical accuracy ranged from 0.7 to 4 mm and postoperative discrepancy ranged from 0.05 to 8 mm. Benefits included improved intraoperative surgical accuracy (95.2%), improved postoperative surgical discrepancy (52.4%), and decreased total surgical time (35.7%). Limitations reported with iCAN device use included operative technical difficulties (23.8%) and persistent systematic errors during device registration (21.4%). None of the studies discussed cost analysis or risks compared to conventional fixation methods.

CONCLUSIONS

Advancements in and increasing familiarity with iCAN technology have preliminarily shown favorable surgical outcomes in facial fracture fixation, which include improved operative accuracy and discrepancy and decreased surgical time.

Guidelines for Orbital Defect Assessment and Patient-Specific Implant Design: Introducing OA2 (Orbital Assessment Algorithm)

Study Design

This study presents a review of the evolutionary development in reconstructive orbital surgery over the past 3 decades. Additionally, it proposes the Orbital Assessment Algorithm (OA2) to enhance decision-making for intraorbital reconstruction of post-traumatic orbital deformities.

Objective

The objective of this paper is to provide insights into modern post-traumatic orbital reconstruction from a surgeon's perspective, with a specific focus on adult patients. It aims to highlight the advancements in computer-aided design and manufacturing techniques, particularly in the field of reconstructive orbital surgery, and to introduce the OA2 as a tool for improved decision-making in this context.

Methods

The study conducts a comprehensive review of the evolution of reconstructive orbital surgery, focusing on the integration of 3D technology into surgical practices. It also outlines the development and rationale behind the proposed OA2, emphasizing its potential to enhance the accuracy and efficacy of intraorbital reconstruction procedures for post-traumatic deformities.

Results

The review demonstrates the significant progress made in reconstructive orbital surgery, particularly in leveraging 3D technology for virtual modeling, navigation, and the design and manufacturing of patient-specific implants. The introduction of the OA2 provides a structured approach to assessing and addressing post-traumatic orbital deformities, offering potential benefits in decision-making and surgical outcomes.

Conclusions

In conclusion, this paper underscores the pivotal role of computer-aided design and manufacturing in advancing reconstructive orbital surgery. It highlights the importance of integrating innovative design concepts into implant manufacturing processes and emphasizes the potential of the OA2 to guide surgeons in the management of post-traumatic orbital deformities, ultimately contributing to improved patient outcomes.

Does a Point-of-Care 3-Dimensional Printer Result in a Decreased Length of Surgery for Orbital Fractures?

BACKGROUND

Utilization of point-of-care 3-dimensional printing (3DP) has decreased length of surgery in facial trauma. Little is known regarding 3DP's impact on length of surgery in orbital fracture.

PURPOSE

The purpose of this study was to compare length of surgery between 3DP/preadapted (3DPPA) orbital plates and intraoperative adapted plates (IOAP) for orbital fracture reconstruction.

STUDY DESIGN, SETTING, SAMPLE

This was a prospective, non-blinded, randomized clinical study of consecutive subjects with orbital fractures presented to Grady Memorial Hospital in Atlanta, Georgia, between January 2018 and June 2021. Subjects ≥ 18 years, unilateral fracture, no previous orbital surgery, and/or congenital craniofacial anomaly were included. We excluded subjects <18 years and bilateral fractures.

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE

Primary predictor variable was the treatment approach. Randomization software was used, and subjects were randomized to 3DPPA or IOAP groups.

MAIN OUTCOME VARIABLE(S)

Primary outcome variable was length of surgery in minutes. Secondary outcomes were the time required for plate insertion and fixation in minutes, operating room (OR) charges, and orbital volume (OV) calculation.

COVARIATES

Age, sex, race, etiology, laterality, location, dimension, indication for surgery, postoperative enophthalmos, and diplopia.

ANALYSES

Univariate and bivariate analyses were calculated. Statistical significance was P < .05.

RESULTS

Twenty-five subjects met the inclusion criteria. Mean ages in 3DPPA and conventional IOAP groups were 41.5 (±9) and 38.2 (±10, P = .31), respectively. The mean length of surgery was 32.6 (±13.7) in 3DPPA and 53.3 (±12.8, P < .001) in conventional IOAP. The mean time required for plate insertion and fixation was 15.8n (±14.4) in 3DPPA and 41.4 (±9.4, P < .001) in conventional IOAP. The mean OR charges were $1,072.5 (±524.6) in 3DPPA and $1,757.3 (±422.6, P ≤ 0.001) in conventional IOAP. The mean calculated OV of uninjured and reconstructed orbit for the 3DPPA was 23.5 (±3.2)cm3 and 23 (±3.5, P = .37)cm3, respectively. The mean calculated OV of uninjured and reconstructed orbit for conventional IOAP was 28.6 (±3.6)cm3 and 22.8 (±2.6, P < .001)cm3, respectively.

CONCLUSION AND RELEVANCE

Using 3DP to produce a model that enables preoperative plate bending/adaptation reduces the length of surgery, decreases OR charges, and results in predictable OV.

The impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures

PURPOSE

The orbital floor is frequently involved in head trauma. Current evidence on the use of reconstruction materials for orbital floor repair is inconclusive. Accordingly, this study aimed to compare the impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures.

METHODS

Standardized isolated orbital floor fractures were symmetrically created in 11 cadaver heads that provided 22 orbits. PDS foils with thicknesses of 0.25-0.5 mm were inserted. Computed tomography (CT) scans of the native, fractured, and reconstructed orbits were obtained, and orbital volume, orbital height, and foil bending were measured.

RESULTS

Orbital volume and height significantly (p < 0.01) increased after the creation of isolated orbital floor fractures and significantly (p = 0.001) decreased with overcorrection of the orbital geometry after orbital floor reconstruction with PDS 0.25 mm or PDS 0.5 mm. The orbital geometry reconstruction rate did not differ significantly with respect to foil thickness. However, compared to PDS 0.5 mm, the use of PDS 0.25 mm resulted in quantitatively higher reconstructive accuracy and a restored orbital volume that did not significantly differ from the initial volume.

CONCLUSION

Orbital floors subjected to isolated fractures were successfully reconstructed using PDS regardless of foil thickness, with overcorrection of the orbital geometry. Due to its lower flexural stiffness, PDS 0.25 mm appeared to provide more accurate orbital geometry reconstruction than PDS 0.5 mm, although no significant difference in reconstructive accuracy between PDS 0.25 mm and PDS 0.5 mm was observed in this cadaveric study.

Does Intraoperative Navigation Improve Implant Position Accuracy in Orbital Fracture Repair?

Purpose: Our aim was to determine if intraoperative navigation (ION) improved radiographic outcomes in patients undergoing delayed primary/secondary orbital reconstruction for inferomedial defects, as measured by volume restoration, enophthalmos correction, and positional accuracy of implants. Patients and Methods: A prospective quasiexperimental study was performed to compare two groups of patients requiring orbital reconstruction. Use of ION was the exposure evaluated. Outcome measures were (i) intraorbital volume and enophthalmos evaluated radiologically, (ii) implant position accuracy, and (iii) procedural duration. Data were analyzed statistically to compare variance between groups. Results: Forty patients (6 females and 34 males) were recruited into the study with a mean age of 27.3 years. The study group demonstrated a greater reduction of intraorbital volume (0.49 cu.cm; p = 0.02) and enophthalmos (0.72 mm; p = 0.001). Implant positioning was more accurate using ION, with less mediolateral (p = 0.006) and yaw (p = 0.04) deviations. Surgical time for implant positioning was shorter by 17 min, with navigation (p < 0.001). Conclusion: The use of ION demonstrated radiographic improvements in volume restoration, enophthalmos correction, as well as accuracy of implant positioning, in patients requiring delayed primary/secondary orbital reconstruction.

aXonica: A support package for MRI based Neuroimaging

Magnetic Resonance Imaging (MRI) assists in studying the nervous system. MRI scans undergo significant processing before presenting the final images to medical practitioners. These processes are executed with ease due to excellent software pipelines. However, establishing software workstations is non-trivial and requires researchers in life sciences to be comfortable in downloading, installing, and scripting software that is non-user-friendly and may lack basic GUI. As researchers struggle with these skills, there is a dire need to develop software packages that can automatically install software pipelines speeding up building software workstations and laboratories. Previous solutions include NeuroDebian, BIDS Apps, Flywheel, QMENTA, Boutiques, Brainlife and Neurodesk. Overall, all these solutions complement each other. NeuroDebian covers neuroscience and has a wider scope, providing only 51 tools for MRI. Whereas, BIDS Apps is committed to the BIDS format, covering only 45 software related to MRI. Boutiques is more flexible, facilitating its pipelines to be easily installed as separate containers, validated, published, and executed. Whereas, both Flywheel and Qmenta are propriety, leaving four for users looking for 'free for use' tools, i.e., NeuroDebian, Brainlife, Neurodesk, and BIDS Apps. This paper presents an extensive survey of 317 tools published in MRI-based neuroimaging in the last ten years, along with 'aXonica,' an MRI-based neuroimaging support package that is unbiased towards any formatting standards and provides 130 applications, more than that of NeuroDebian (51), BIDS App (45), Flywheel (70), and Neurodesk (85). Using a technology stack that employs GUI as the front-end and shell scripted back-end, aXonica provides (i) 130 tools that span the entire MRI-based neuroimaging analysis, and allow the user to (ii) select the software of their choice, (iii) automatically resolve individual dependencies and (iv) installs them. Hence, aXonica can serve as an important resource for researchers and teachers working in the field of MRI-based Neuroimaging to (a) develop software workstations, and/or (b) install newer tools in their existing workstations.

Does Integration of Technology and Customization of Implants Produce Better Outcomes in Post-Traumatic Orbital Reconstruction? A Systematic Review and Meta-Analysis

PURPOSE

This review aims to compare and evaluate the outcomes achieved by integrating technological aids and the influence of different implant designs in the reconstruction of post-traumatic orbital defects.

METHODS

Electronic searches of the MEDLINE, Embase, Cochrane Library, and Google Scholar databases until March 2023 were conducted. Clinical controlled trials, observational studies, cohort studies, and retrospective studies were identified and included. The predictor variables were the integration of technological aids namely, computer-assisted surgical planning, mirror image overlay, and intraoperative navigation with the utilization of different orbital implant designs (standard orbital meshes, preformed implants, prebent implants, and patient-specific implant [PSI]) during post-traumatic orbital reconstruction. The primary outcome variables were orbital volume, diplopia, and enophthalmos. Weighted or mean difference and risk ratios at 95% confidence intervals were calculated, where P ＜ .05 was considered significant and a random effects model was adopted.

RESULTS

This review included 7 studies with 560 participants. The results indicate that the difference in postoperative orbital volume between affected and nonaffected eye showed no statistically significant difference between PSI and prebent group (mean difference, -0.41 P = .28, I2 = 46%). PSI group resulted in diplopia 0.71-fold less than that of the standard orbital mesh group but was not statistically significant (P = .15). Standard orbital mesh group is 0.30 times at higher risk of developing enophthalmos as compared to PSI group (P = .010). The literature suggests PSIs are preferred for patients with large defects (Jaquiéry's III-IV), whereas prebent implants are equally effective as PSIs in patients with preserved infraorbital buttress and retrobulbar bulge.

CONCLUSION

PSIs are associated with improved outcomes, especially for correcting enophthalmos. The data suggests the potential efficacy of prebent implants and PSIs in orbital volume corrections. There is a lack of randomized studies. This review should serve as a recommendation for further studies to contribute to the existing literature.

Classical Orbital Floor Post-Traumatic Reconstruction vs. Customized Reconstruction with the Support of "In-House" 3D-Printed Models: A Retrospective Study with an Analysis of Volumetric Measurement

BACKGROUND

Orbital floor fractures (OFFs) represent an interesting chapter in maxillofacial surgery, and one of the main challenges in orbit reconstruction is shaping and cutting the precise contour of the implants due to its complex anatomy.

OBJECTIVE

The aim of the retrospective study was to demonstrate, through pre- and postoperative volumetric measurements of the orbit, how the use of a preformed titanium mesh based on the stereolithographic model produced with 3D printers ("In-House" reconstruction) provides a better reconstruction volumetric compared to the intraoperatively shaped titanium mesh.

MATERIALS AND METHODS

The patients with OFF enrolled in this study were divided into two groups according to the inclusion criteria. In Group 1 (G1), patients surgically treated for OFF were divided into two subgroups: G1a, patients undergoing orbital floor reconstruction with an intraoperatively shaped mesh, and G1b, patients undergoing orbital floor reconstruction with a preoperative mesh shaped on a 3D-printed stereolithographic model. Group 2 (G2) consisted of patients treated for other traumatic pathologies (mandible fractures and middle face fractures not involving orbit). Pre- and postoperative orbital volumetric measurements were performed on both G1 and G2. The patients of both groups were subjected to the measurement of orbital volume using Osirix software (Pixmeo SARL, CH-1233 Bernex, Switzerland) on the new CT examination. Both descriptive (using central tendency indices such as mean and range) and regressive (using the Bravais-Pearson index, calculated using the GraphPad program) statistical analyses were performed on the recorded data.

RESULTS

From 1 January 2017 to 31 December 2021, of the 176 patients treated for OFF at the "Magna Graecia" University Hospital of Catanzaro 10 fulfilled the study's inclusion criteria: 5 were assigned to G1a and 5 to G1b, with a total of 30 volumetric measurements. In G2, we included 10 patients, with a total of 20 volumetric measurements. From the volumetric measurements and statistical analysis carried out, it emerged that the average of the volumetric differences of the healthy orbits was ±0.6351 cm3, the standard deviation of the volumetric differences was ±0.3383, and the relationship between the treated orbit and the healthy orbit was linear; therefore, the treated orbital volumes tend to approach the healthy ones after surgical treatment.

CONCLUSION

This study demonstrates that if the volume is restored within the range of the standardized mean, the diplopia is completely recovered already after surgery or after one month. For orbital volumes that do not fall within this range, functional recovery could occur within 6 months or be lacking. The restoration of the orbital volume using pre-modeled networks on the patient's anatomical model, printed internally in 3D, allows for more accurate reconstructions of the orbital floor in less time, with clinical advantages also in terms of surgical timing.

Sculpting the future: A narrative review of 3D printing in plastic surgery and prosthetic devices

Background and Aims

The advent of 3D printing has revolutionized plastic surgery and prosthetic devices, providing personalized solutions for patients with traumatic injuries, deformities, and appearance-related conditions. This review offers a comprehensive overview of 3D printing's applications, advantages, limitations, and future prospects in these fields.

Methods

A literature search was conducted in PubMed, Google Scholar, and Scopus for studies on 3D printing in plastic surgery.

Results

3D printing has significantly contributed to personalized medical interventions, with benefits like enhanced design flexibility, reduced production time, and improved patient outcomes. Using computer-aided design (CAD) software, precise models tailored to a patient's anatomy can be created, ensuring better fit, functionality, and comfort. 3D printing allows for intricate geometries, leading to improved aesthetic outcomes and patient-specific prosthetic limbs and orthoses. The historical development of 3D printing, key milestones, and breakthroughs are highlighted. Recent progress in bioprinting and tissue engineering shows promising applications in regenerative medicine and transplantation. The integration of AI and automation with 3D printing enhances surgical planning and outcomes. Emerging trends in patient-specific treatment planning and precision medicine are potential game-changers. However, challenges like technical considerations, economic implications, and ethical issues exist. Addressing these challenges and advancing research in materials, design processes, and long-term outcomes are crucial for widespread adoption.

Conclusion

The review underscores the increasing adoption of 3D printing in healthcare and its impact on plastic surgery and prosthetic devices. It emphasizes the importance of evaluating the current state and addressing knowledge gaps through future research to foster further advancements.

Customized orbital implant versus 3D preformed titanium mesh for orbital fracture repair: A retrospective comparative analysis of orbital reconstruction accuracy

This study aimed to compare the accuracy of inferomedial orbital fracture restoration using customized orbital implant versus 3D preformed titanium mesh. Patients were divided into two groups. Group 1 underwent surgery with customized orbital implants and intraoperative navigation, while group 2 was treated using 3D preformed titanium meshes with preoperative virtual surgical planning (VSP) and intraoperative navigation. Reconstruction accuracy was assessed by: (1) comparing the postoperative reconstruction mesh position with the preoperative VSP; and (2) measuring the difference between the reconstructed and unaffected orbital volume. Pre- and postoperative diplopia and enophthalmos were also evaluated. Fifty-two patients were enrolled (25 in group 1 vs 27 in group 2). The mean difference between final plate position and ideal digital plan was 0.62 mm (SD = 0.235) in group 1 and 0.69 mm (SD = 0.246) in group 2, with no statistical difference between the groups (p = 0.282). The mean volume differences between the reconstructed and unaffected orbits were 0.95 ml and 1.02 ml in group 1 and group 2, respectively, with no significant difference between the groups (p = 0.860). Overall clinical improvements, as well as complications, were similar. 3D preformed titanium meshes can reconstruct inferomedial fractures with the same accuracy as customized implants. Therefore, in clinical practice, it is recommended to use 3D preformed meshes for this type of fracture due to their excellent results and the potential for reducing time and costs.

Patient-Specific Implant Customization for Treatment of Internal Orbital Fractures Using Office-Based Three-Dimensional Printing

OBJECTIVE

Three-dimensional (3D) modeling technology aids the reconstructive surgeon in designing and tailoring individualized implants for the reconstruction of complex craniofacial fractures. Three-dimensional modeling and printing have traditionally been outsourced to commercial vendors but can now be incorporated into both private and academic craniomaxillofacial practices. The goal of this report is to present a low-cost, standardized office-based workflow for restoring bony orbital volume in traumatic orbital fractures.

METHODS

Patients with internal orbital fractures requiring open repair were identified. After the virtual 3D models were created by iPlan 3.0 Cranial CMF software (Brainlab), the models were printed using an office-based 3D printer to shape and modify orbital plates to correctly fit the fracture defect. The accuracy of the anatomic reduction and the restored bony orbital volume measurements were determined using postoperative computed tomography images and iPlan software.

RESULTS

Nine patients fulfilled the inclusion criteria: 8 patients had unilateral fractures and 1 patient had bilateral fractures. Average image processing and print time were 1.5 hours and 3 hours, respectively. The cost of the 3D printer was $2500 and the average material cost to print a single orbital model was $2. When compared with the uninjured side, the mean preoperative orbital volume increase and percent difference were 2.7 ± 1.3 mL and 10.9 ± 5.3%, respectively. Postoperative absolute volume and percent volume difference between the orbits were -0.2 ± 0.4 mL and -0.8 ± 1.7%, respectively.

CONCLUSIONS

Office-based 3D printing can be routinely used in the repair of internal orbital fractures in an efficient and cost-effective manner to design the implant with satisfactory patient outcomes.

Can a Point-of-Care 3D Printing Workflow Produce Accurate and Successful Results for Craniomaxillofacial Trauma?

BACKGROUND

Computer-aided design and manufacturing (CAD/CAM) is having a profound impact on craniomaxillofacial surgery, and point-of-care (POC) solutions for repairing facial trauma are starting to emerge.

PURPOSE

The purpose of this study was to demonstrate the success and accuracy of a POC 3D printing workflow for craniomaxillofacial trauma.

STUDY DESIGN, SETTING, SAMPLE

A retrospective cohort study was undertaken to analyze subjects presenting to a level 1 trauma center after sustaining facial trauma and were then treated using the POC 3D printing workflow. Subjects were excluded if they were not treated with the POC 3D printing workflow, were lost to follow-up, or if clinical data were incomplete.

PREDICTOR VARIABLE

Predictor variables included the cause of trauma (mechanism), location of the mandibular fracture, type of fracture, mandibular severity score, and repair error (ie, root mean square error (RMSE) value for planned vs actual outcome).

MAIN OUTCOME VARIABLE(S)

The primary outcome variables were case success and case error. Success was defined as clinical and radiographic evidence of bony stability at 3 months. Case accuracy was calculated overlaying preoperative plan data to postoperative data generating a numerical value (RMSE value, mm).

COVARIATES

Covariates included age (years), gender (male/female), surgery time (mins), and CAD/CAM time (preoperative).

ANALYSES

Descriptive statistics were calculated for each variable. Dependence between rates or counts was established using the Wilcoxon rank sum or Fisher's exact test. Linear regression model was computed to discern how predictor variables influence RMSE. A P value < .05 was considered statistically significant.

RESULTS

The sample included 27 subjects (19 male/8 female). The average age of all subjects was 46.4 ± 18.0 years. Common mechanisms of injury were assault (33%) and self-inflicted gunshots (SIGSW; 30%), and the average severity score for mandible injury was (13.5 ± 3.3). Ninety-three percent of cases were deemed successful. The average repair accuracy (RMSE value) was 3.4 ± 1.8 mm. A linear regression model indicated those injured by a fall (β-coefficient 1.99; P = .010), motor vehicle collision (β-coefficient 1.49; P = .043), or SIGSW (β-coefficient 2.82; P < .001) correlated with RMSE.

CONCLUSION AND RELEVANCE

In-house CAD/CAM technologies can be utilized at the POC to repair complex facial trauma accurately and successfully.

Efficacy and Safety of Expanded Polytetrafluoroethylene Implantation in the Correction of Long-Term Posttraumatic Enophthalmos

SUMMARY

Long-term enophthalmos is a common orbital fracture sequela. Various autografts and alloplastic materials have been studied in posttraumatic enophthalmos repair. However, expanded polytetrafluoroethylene (ePTFE) implantation in late enophthalmos repair has rarely been reported. The authors report novel use of ePTFE for late posttraumatic enophthalmos repair. This retrospective study included patients with posttraumatic long-term enophthalmos who underwent hand-carved ePTFE intraorbital implantation for enophthalmos correction. Computed tomography data were collected preoperatively and at follow-up. The volume of ePTFE, the degree of proptosis (DP), and enophthalmos were measured. Postoperative and preoperative DP and enophthalmos were compared using the paired t test. The correlation between ePTFE volume and DP increment was established using linear regression. Complications were identified by chart review. From 2014 to 2021, 32 patients were included, with a mean follow-up of 19.59 months. The mean volume of implanted ePTFE was 2.39 ± 0.89 mL. After surgery, the DP of the affected globe improved significantly, from 12.75 ± 2.12 mm to 15.06 ± 2.50 mm ( P < 0.0001). A significant linear correlation was found between ePTFE volume and DP increment ( P < 0.0001). Enophthalmos was substantially ameliorated from 3.35 ± 1.89 mm to 1.09 ± 2.07 mm ( P < 0.0001). Twenty-five patients (78.23%) had postoperative enophthalmos of less than 2 mm. Infection and implant dislocation were not observed. The authors concluded that ePTFE intraorbital implantation exhibited long-term efficacy and safety for late posttraumatic enophthalmos repair and represents an effective and predictable alternative.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Modified individualized titanium mesh in orbital floor reconstruction for preventing exposure

Objective

To describe a novel method of medial fixation of titanium mesh with a right-angled screwdriver for orbital floor and maxillary reconstruction and to compare the reconstruction outcome of orbital floor reconstruction with modified and traditional methods.

Methods

The data of 23 patients who underwent maxillectomy and orbital floor defect reconstruction by individualized titanium mesh in Peking University School and Hospital of Stomatology between 2018 and 2021 were retrospectively reviewed. While eight patients received modified orbital floor reconstruction with titanium mesh and angled screwdriver (group A), 15 patients received traditional orbital floor reconstruction (group B). The contact area with buccal flap for titanium mesh in groups A and B was calculated. Titanium mesh deformation, fracture or exposure was recorded. Postoperative ophthalmic function and success of esthetic restoration were assessed.

Results

Mean follow-up was for 15.7 months (range, 9-22 months). The contact area with buccal flap for the modified titanium mesh in group A (13.11 ± 1.41 cm2) was significantly less than that of the traditional titanium mesh in group B (21.83 ± 1.23 cm2; p < .05). The exposure of titanium mesh occurred in two patients in group B. The self-evaluation of facial symmetry for 23 patients showed no significant difference between group A (7.75 ± 0.71) and group B (6.68 ± 1.30; p > .05). No specific complications were reported.

Conclusion

We propose a novel method of zygomatic medial fixation of titanium mesh with a right-angled screwdriver for orbital floor and maxillary reconstruction, which has the potential to prevent the postoperative exposure of titanium mesh.

Level of Evidence

Level III (Retrospective comparative study).

Accuracy of Orbital Shape Reconstruction-Comparative Analysis of Errors in Implant Shape Versus Implant Positioning: A Cadaveric Study

INTRODUCTION

Orbital blowout fractures are commonly reconstructed with implants shaped to repair orbital cavity defects, restore ocular position and projection, and correct diplopia. Orbital implant shaping has traditionally been performed manually by surgeons, with more recent use of computer-assisted design (CAD). Accuracy of implant placement is also key to reconstruction. This study compares the placement accuracy of orbital implants, testing the hypothesis that CAD-shaped implants indexed to patient anatomy will better restore orbit geometry compared with manually shaped implants and manually placed implants.

METHODS

The placement accuracy of orbital implants was assessed within a cadaveric blowout fracture model (3 skulls, 6 orbits) via 3-dimensional CT analysis. Defects were repaired with 4 different techniques: manually placed-manually shaped composite (titanium-reinforced porous polyethylene), manually placed CAD composite, indexed placed CAD composite, and indexed placed CAD titanium mesh.

RESULTS

Implant placement accuracy differed significantly with the implant preparation method ( P =0.01). Indexing significantly improved the placement accuracy ( P =0.002). Indexed placed titanium mesh CAD implants (1.42±0.33 mm) were positioned significantly closer to the intact surface versus manually placed-manually shaped composite implants (2.12±0.39 mm).

DISCUSSION

Computer-assisted design implants indexed to patient geometry yielded average errors below the acceptable threshold (2 mm) for enophthalmos and diplopia. This study highlights the importance of adequately indexing CAD-designed implants to patient geometry to ensure accurate orbital reconstructions.

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.

Is the Pre-Shaping of an Orbital Implant on a Patient-Specific 3D-Printed Model Advantageous Compared to Conventional Free-Hand Shaping? A Systematic Review and Meta-Analysis

This study aimed to perform a systematic review and meta-analysis to compare pre-shaped implants on a patient-specific 3D-printed (3DP) model to manual free-hand shaping (MFS) for orbital wall reconstruction. The PRISMA protocol was followed in this study, and the review was registered in the PROSPERO database (CRD42021261594). A search was conducted in MEDLINE (PubMed), Embase, Cochrane Library, Clinicaltrials.gov, Google Scholar, and the grey literature. Ten articles were included, and six outcomes were analyzed. In total, 281 patients were in the 3DP group and 283 were in the MFS group. The studies had an overall high risk of bias. 3DP models resulted in a better accuracy of fit, anatomical angle reproduction, and defect area coverage. The correction of orbital volume was also superior with statistical significance. There was a higher percentage of the correction of enophthalmos and diplopia in the 3DP group. Intraoperative bleeding and hospital stay were reduced in the 3DP group. The meta-analysis of operative time showed a reduction in the average operative time by 23.58 min (95% CI: -43.98 to -3.19), which was statistically significant (t(6) = -2.8299, p = 0.0300). The 3DP models appear advantageous for an accurate orbital wall reconstruction, with fewer complications than those for conventional free-hand-shaped implants.

A retrospective comparison between one-stage and two-stage orbital reconstruction in patients suffering from combined injuries of the midface

Reconstruction of the bony orbit in patients with combined midface injuries is frequently discussed in the current literature. Two main concepts can be distinguished: single-stage reconstruction, usually with a hand-bent titanium orbital mesh, and two-stage reconstruction, in which osteosynthesis of the zygomaticomaxillary complex (ZMC) is followed by orbital reconstruction with a virtually-planned, patient-specific titanium implant in a second surgery. This study aimed to compare one-stage and two-stage surgical approaches on combined midface fractures regarding postoperative diplopia. A total of 58 patients treated with one-stage (n = 29) or two-stage (n = 29) reconstruction of the ZMC and orbit were included, and their postoperative course over five months was retrospectively analysed. A descriptive quantitative analysis of the course of occurrence of diplopia was recorded to calculate the success of orbital repair in complex midface fractures including the orbit. The two workflows differed in the prevalence of postoperative clinical diplopia and eyelid complications. Multiple factors affect the decision whether or not to reconstruct the orbit first, and in the same intervention as the associated midface fracture. Thorough evaluation of each individual patient with a patient-specific choice of surgical concept is crucial, and includes multiple factors.

Comparison of Postoperative Enophthalmos Between Fresh and Delayed Unilateral Orbital Fractures After Orbital Reconstruction With Titanium Mesh Using Computer-Assisted Navigation

This study compares postoperative enophthalmos between fresh and delayed unilateral orbital fractures after orbital reconstruction with titanium mesh using computer-assisted navigation. The sample was composed of 45 patients with post-traumatic unilateral enophthalmos who were divided into the fresh fracture group and the delayed fracture group. They underwent orbital reconstruction with standard preformed orbital implants and computer-assisted navigation system. The following parameters were measured with computed tomography images: the degree of enophthalmos, orbital volume, and fracture defect area. Patients were reviewed preoperatively (T0), 1 week postoperatively (T1), and 6 months postoperatively (T2). Computed tomography measurements showed that in both groups, the degree of enophthalmos decreased after surgery but increased significantly from T1 to T2 ( P <0.05). ΔE (difference in the degree of enophthalmos between T1 and T2) was similar in patients with fresh and delayed fractures. There was a significant difference in the degree of ΔE between patients with single-wall orbital fractures and those with two-wall orbital fractures. The findings indicate that postoperative enophthalmos is common in both the groups and is closely related to the degree of preoperative enophthalmos. Furthermore, the recurrence of enophthalmos is similar between the 2 groups, but it is higher in patients with orbital fractures involving 2 walls.

Accuracy of anatomic 3-dimensionally printed canine humeral models

OBJECTIVE

To evaluate the accuracy of various three-dimensional print (3DP) technologies using morphometric measurements.

STUDY DESIGN

Experimental.

SAMPLE POPULATION

Cadaveric canine humeri and size-matched 3DP models.

METHODS

Fiduciary radiopaque markers were affixed to canine humeri of three different sizes (4, 13, 29 kg) at predetermined anatomical landmarks. 3DP models were created using one of three printers; desktop printers Form 3L and Ultimaker 5S, and industrial printer Objet Connex (n = 5/group/printer). Marker based morphometric dimensions between cadavers and 3DP models were statistically compared using 2-factor repeated measures ANOVA followed by Tukey's post-hoc test (p < .05).

RESULTS

Bone size and printer type both significantly affected 3DP accuracy, with size having the larger effect (p < .0001 and p < .02, respectively). Regardless of printing technology, model size was smaller than native bone in most cases. At the humeral condylar level, the best accuracy was seen in the medium-sized humerus with the Ultimaker printer ([0.09 mm], p < .03). Accuracy was reduced in the proximal humerus in all groups.

CONCLUSION

Desktop printers were overall more accurate than the industrial printer. Although significant differences were identified between models of different sizes, the submillimetric magnitude of these differences is unlikely to be clinically relevant.

CLINICAL SIGNIFICANCE

While preoperative planning using 3DP models is becoming mainstream, accurate representation of the actual bone is critical. This study demonstrates that common desktop printers are suitable for this purpose.

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.

Prospective Evaluation of Two Wall Orbital Fractures Involving the Medial Orbital Wall: PSI Reconstruction versus PDS Repair—Worth the Effort?

Proper treatment of the two-wall fractured orbit is still controversial. Specifically, there is no consensus on the issue of the necessity of medial orbital wall repair. With anatomically critical structures at risk during the surgical approach, surgeons’ view on the necessity of medial orbital wall repair often is restricted and an aesthetically disturbing enophthalmos is more likely to be accepted. Therefore, treatment options range from leaving the medial wall without repair to reconstruction with autogenous tissue or alloplastic materials, which can lead to moderate to severe side effects. However, emerging technologies such as patient-specific implants (PSI) offer a reliable and anatomically correct reconstruction of the bony orbit. This study aimed to evaluate the outcome of full orbital reconstruction using PSIs compared to only orbital floor repair using PDS (bioresorbable polydioxanone) foils leaving the medial orbital wall untouched in traumatic two-wall orbital fractures. Of all patients treated at the University Hospital of Düsseldorf between 2017 and 2019 who suffered from traumatic orbital fracture, only patients with a two-wall orbital fracture involving both the orbital floor and the medial wall (n = 68) were included. Patients were treated either with a PSI (n = 35) or a PDS foil (n = 33). Primary outcome parameters were ophthalmological disturbances analyzed via clinical investigation and intra-orbital angles, volumes and implant position analyzed with radiological 3D-datasets. While a two-wall reconstruction using PSIs led to a significant improvement of the enophthalmos, the rate of postoperative enophthalmos was significantly increased in cases of only orbital floor repair with PDS foils. Radiologically, a significant reconstruction of the three-dimensional bony orbit succeeded with the simple use of PSIs leading to a significant reduction in the traumatically enlarged orbital volume. PSI also led to a significant reduction in the traumatically enlarged medial angle of the orbit. This was not the case for single-floor repair with PDS foil. The results of this study suggest that complex orbital fractures can be reconstructed at an even higher degree of accuracy with selective laser-melted PSIs than PDS foils. In order to achieve a true to original reconstruction of the bony orbit, surgical treatment of the medial orbital wall can be advocated for in the long term depending on the indication.

Personalized Medicine Workflow in Post-Traumatic Orbital Reconstruction

Restoration of the orbit is the first and most predictable step in the surgical treatment of orbital fractures. Orbital reconstruction is keyhole surgery performed in a confined space. A technology-supported workflow called computer-assisted surgery (CAS) has become the standard for complex orbital traumatology in many hospitals. CAS technology has catalyzed the incorporation of personalized medicine in orbital reconstruction. The complete workflow consists of diagnostics, planning, surgery and evaluation. Advanced diagnostics and virtual surgical planning are techniques utilized in the preoperative phase to optimally prepare for surgery and adapt the treatment to the patient. Further personalization of the treatment is possible if reconstruction is performed with a patient-specific implant and several design options are available to tailor the implant to individual needs. Intraoperatively, visual appraisal is used to assess the obtained implant position. Surgical navigation, intraoperative imaging, and specific PSI design options are able to enhance feedback in the CAS workflow. Evaluation of the surgical result can be performed both qualitatively and quantitatively. Throughout the entire workflow, the concepts of CAS and personalized medicine are intertwined. A combination of the techniques may be applied in order to achieve the most optimal clinical outcome. The goal of this article is to provide a complete overview of the workflow for post-traumatic orbital reconstruction, with an in-depth description of the available personalization and CAS options.

Prospective Evaluation of Intraorbital Soft Tissue Atrophy after Posttraumatic Bone Reconstruction: A Risk Factor for Enophthalmos

Orbital fractures are a common finding in facial trauma, and serious complications may arise when orbital reconstruction is not performed properly. The virtual planning can be used to print stereolithographic models or to manufacture patient-specific titanium orbital implants (PSIs) through the process of selective laser melting. This method is currently considered the most accurate technique for orbital reconstruction. Even with the most accurate techniques of bone reconstruction, there are still situations where enophthalmos is present postoperatively, and it may be produced by intraorbital soft tissue atrophy. The aim of this paper was to evaluate the orbital soft tissue after posttraumatic reconstruction of the orbital walls’ fractures. Ten patients diagnosed and treated for unilateral orbital fractures were included in this prospective study. A postoperative CT scan of the head region with thin slices (0.6 mm) and soft and bone tissue windows was performed after at least 6 months. After data processing, the STL files were exported, and the bony volume, intraorbital fat tissue volume, and the muscular tissue volume were measured. The volumes of the reconstructed orbit tissues were compared with the volumes of the healthy orbit tissues for each patient. Our findings conclude that a higher or a lower grade of fat and muscular tissue loss is present in all cases of reconstructed orbital fractures. This can stand as a guide for primary or secondary soft tissue augmentation in orbital reconstruction.

Customised products for orbital wall reconstruction: a systematic review

The purpose of this systematic review was to critically analyse the recent literature and present the state of the art in customised reconstruction of orbital fractures. Three electronic databases and manual search approaches were used to identify relevant articles. Only controlled clinical studies were included. Primary outcome was defined as the status of recovery (complete/partial functional, and aesthetic disturbances). The benefit of intrasurgical navigation should be described. The secondary outcome was defined as the time of surgery, post-surgical events, and hospitalisation. Of the 552 records identified, eight met the inclusion criteria. Post-surgical results regarding recovery were superior in the customised group, and were comparable to the control group in five studies. The time of surgery was shorter in the customised groups, and liquid infusion and time of hospitalisation were reduced. Four studies documented more accurate reconstruction with the use of navigation. All the studies presented at least one bias, and considerable heterogeneity was evaluated. This review found that the use of customised meshes in combination with surgical navigation resulted in more accurate reconstruction. A significant reduction in surgical time was revealed.

Orbital reconstruction: a systematic review and meta-analysis evaluating the role of patient-specific implants

The purpose of this study is to execute an evidence-based review answering the following question (PICO): "Do patient-specific implants (PSI), manufactured or designed using computer-assisted technology, improve outcomes (orbital volume change, enophthalmos, diplopia, and operative duration) compared to conventional methods in orbital reconstruction following traumatic orbital injury in the adult patient population?" We performed a systematic review and meta-analysis in accordance with PRISMA guidelines. Inclusion criteria included any comparative paper whereby computer-assisted technology was used in the prefabrication or design process of implants for use in post-traumatic orbital reconstruction. Paediatric patient populations were excluded. Eight databases were systematically searched for relevant studies. Risk of bias was assessed through the NOS and RoB2 tools. Random-effects models were used to identify differences in outcomes between groups where possible. Analysis was performed using R 4.0.0. Eleven of 4784 identified studies were included, comprising 628 adult patients, with 302 and 326 patients in the patient-specific and conventional groups, respectively. Weighted mean difference between unaffected and post-operative orbital volume was 0.32 ml (SD 0.75) and 0.95 ml (SD 1.03) for patient-specific and conventional groups, respectively. Significant improvement was identified in post-operative orbital volume reconstitution with the use of PSI, compared to conventional implants, in 3 of the 5 reporting studies. Equally, post-operative enophthalmos trended towards lower severity in the patient-specific group, with 11.2% of patients affected in the patient-specific group and 19.2% in the conventional group, and operative duration was significantly reduced with the use of PSI in 3 of the 6 reporting studies. Despite a tendency to favour PSI, no statistically significant differences in key outcomes were identified on meta-analysis. Although there is some encouraging data to support improved outcomes with the use of patient-specific orbital implants in post-traumatic reconstruction, there is, at present, no statistically significant evidence to objectively support their use over conventional implants based on the currently available comparative studies. Based on the results of this study, the choice of implant used should, thus, be left to the discretion of the surgeon.

Preliminary outcomes of the surgical navigation system combined with intraoperative three-dimensional C-arm computed tomography for zygomatico-orbital fracture reconstruction

This study analyzed the outcomes of zygomatico-orbital fracture reconstruction using the real-time navigation system with intraoperative three-dimensional (3D) C-arm computed tomography (CT). Fifteen patients with zygomatico-orbital or isolated orbital/zygoma fractures were enrolled in this prospective cohort. For zygoma reduction, the displacement at five key sutures and the differences between preoperative and intraoperative CT images were compared. For orbital reconstruction, the bilateral orbital volume differences in the anterior, middle, and posterior angles over the medial transitional buttress were measured. Two patients required implant adjustment once after the intraoperative 3D C-arm assessment. On comparing the preoperative and postoperative findings for the zygoma, the average sum of displacement was 19.48 (range, 5.1–34.65) vs. 1.96 (0–3.95) mm (P < 0.001) and the deviation index was 13.56 (10–24.35) vs. 2.44 (0.6–4.85) (P < 0.001). For the orbit, the mean preoperative to postoperative bilateral orbital volume difference was 3.93 (0.35–10.95) vs. 1.05 (0.12–3.61) mm³ (P < 0.001). The mean difference in the bilateral angles at the transition buttress was significantly decreased postoperatively at the middle and posterior one-third. There was no significant difference in orbital volume, angle of the transition zone, and the sum of five zygoma distances between post operative results and preoperative virtual planning. The surgical navigation system with the intraoperative 3D C-arm can effectively improve the accuracy of zygomatico-orbital fracture reconstruction and decrease implant adjustment times.

Outcome and Quality of Life after Individual Computer-AssistedReconstruction of the Midface

Often, midfacial defects are not only relevant regarding functional aspects but also esthetics of such congenital or acquired deformities impair significantly the patients' quality of life. Reconstructions of the midface do not only include replacing lost or non-developed tissue but moreover to achieve predictable results with regard to esthetics as well as function for the individual patient. Digital planning modalities including different surface and volume data in combination with modern additive manufacturing techniques for biomodel and implant production and intraoperative support by using real and virtual 3D volume data for navigation and intraoperative imaging, but also securing the outcome based on postoperative analysis have been implemented in modern midface reconstruction and represent new standards for medical care. The objective of this paper is to describe modern options of patient-specific midfacial reconstruction with integration of computer-assisted planning and production techniques.

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.

Biocompatible Materials for Orbital Wall Reconstruction-An Overview

The reconstruction of an orbit after complex craniofacial fractures can be extremely demanding. For satisfactory functional and aesthetic results, it is necessary to restore the orbital walls and the craniofacial skeleton using various types of materials. The reconstruction materials can be divided into autografts (bone or cartilage tissue) or allografts (metals, ceramics, or plastic materials, and combinations of these materials). Over time, different types of materials have been used, considering characteristics such as their stability, biocompatibility, cost, safety, and intraoperative flexibility. Although the ideal material for orbital reconstruction could not be unanimously identified, much progress has been achieved in recent years. In this article, we summarise the advantages and disadvantages of each category of reconstruction materials. We also provide an update on improvements in material properties through various modern processing techniques. Good results in reconstructive surgery of the orbit require both material and technological innovations.

"6 Anatomical Landmarks" Technique for Satisfactory Free-Hand Orbital Reconstruction With Standard Preformed Titanium Mesh

Study Design

Retrospective study.

Objective

Resolution of clinical signs and symptoms following orbital fractures depends on the accurate restoration of the orbital volume. Computer-Assisted procedures and Patient Specific Implants represent modern solutions, but they require additional resources. A more reproducible option is the use of standard preformed titanium meshes, widely available and cheaper; with their use quality of results is proportional to the accuracy with which they are positioned. This work identifies 6 reproducible and constant anatomical landmarks, as an intraoperative guide for the precise positioning of titanium preformed meshes.

Methods

90 patients treated at the Maxillofacial Surgery Department, Niguarda Trauma Center, Milan, for unilateral orbital reconstruction (January 2012 to December 2018), were studied. In all cases reconstruction was performed respecting the 6 proposed anatomical landmarks. The outcomes analyzed are: post-operative CT adherence to the 6 anatomical markers and symmetry achieved respect to controlateral orbit; number/year of re-interventions and duration of surgery; resolution of clinical defects (at least 12-months follow-up); incidence of complications.

Results

Satisfactory results were obtained in terms of restoration of orbital size, shape and volume. Clinical defects early recovered with a low incidence of complications and re-interventions. Operating times and radiological accuracy have shown a progressive improvement during years of application of this technique.

Conclusions

The proposed "6 anatomical landmarks" is an easy free-hand technique that allows everyone to obtain high levels of reconstructive accuracy and it should be a skill of all surgeons who deal with orbital reconstruction in daily clinical activity.

Do Patient-Specific Implants Decrease Complications and Increase Orbital Volume Reconstruction Accuracy in Primary Orbital Fracture Reconstruction?

PURPOSE

Patient-specific titanium implants are increasingly used in orbital trauma as a means of achieving improved surgical outcomes as well as decreasing postoperative complications; however, the data to support their use remain limited. The purpose of this study is to compare the complication rates and accuracy of orbital reconstruction using preformed titanium mesh implants and patient-specific implants.

METHODS

The authors conducted a retrospective cohort study consisting of patients with orbital floor and/or medial wall fractures treated by reconstruction with either preformed or patient-specific implants from August 1, 2015 to December 31, 2020. The primary predictor variable was the implant type. Outcome variables were the percent volume difference between the reconstructed and uninjured orbital volume and complications. Statistical analysis was performed using Fisher exact test and Wilcoxon rank-sum test.

RESULTS

Of the 85 patients in the study, 73% were male and the average age was 38.7 ± 16.6 years. Sixty-one patients (72%) were treated with preformed implants and 24 (28%) with patient-specific implants. Complications occurred in 8.3% of the patient-specific implant group and 26.2% of the preformed implant group (P = .08). Percent volume difference between the reconstructed and nontraumatized orbit was 4.2% and 6.8% in the patient-specific and preformed implant group, respectively (P = .03).

CONCLUSIONS

Patient-specific implants improved orbital volume reconstruction accuracy but did not decrease complications when compared to preformed implants.

Pitfalls of Surgeon-Engineer Communication and the Effect of In-House Engineer Training During Digital Planning of Patient-Specific Implants for Orbital Reconstruction

PURPOSE

The use of patient-specific implants for reconstruction of complex orbital floor defects is increasing and requires communication with an industry partner, which warrants investigation. Therefore, the aim of this study was to evaluate the effects of in-house training of engineers on such communication as well as to identify frequent sources of problems and their solutions for improvement of the implant-planning workflow.

METHODS

We conducted a retrospective cross-sectional study and enrolled a sample of patients who had undergone orbital reconstruction with patient-specific implants between 2017 and 2020. The predictor variables were in-house training (additional training completed in hospital or not) and implant complexity (complex [multiwalled implants] vs less complex [isolated orbital floor reconstructions]). The outcome variables were duration of communication, message length, and need for synchronous communication or modifications to the original design. Descriptive, univariate, and multivariate statistics were computed, and statistical significance was set at a P value of < 0.05.

RESULTS

This study included the data of 66 patients (48 men and 18 women, average age: 42.27 years). The complexity of the implant statistically significantly increased the duration of the communication (8.76 vs 16.03 days; P = .004). In 72.73%, the initial design had to be changed. Engineers trained in house required less communication to plan less-complex implants and generally needed fewer corrections to the original design (P = .020 and P = .036, respectively). Problems during planning were observed in 25.76% of the cases, with an insufficient diagnostic 3-dimensional data set being the most common (15.15%).

CONCLUSIONS

In-house training of engineers is time-saving while planning the workflow for patient-specific implants, especially in less-complex cases, given that design changes are not needed often. The high rate of data sets that were insufficient for planning patient-specific implants suggests that diagnostic 3-dimensional data sets should already meet the requirements for such planning.

Contemporary Management of Zygomaticomaxillary Complex Fractures

Zygomaticomaxillary complex fracture is one of the most commonly treated facial fractures. Accurate reduction and stable fixation of the zygoma are required to restore facial symmetry and projection and avoid functional sequalae from changes in orbital volume. Achieving optimal outcome is challenging due to the complex three-dimensional anatomy and limited visualization of all affected articulations of the zygoma. This article provides an updated overview of the evaluation and management of zygomaticomaxillary complex fractures based on available evidence and clinical experience at our center. The importance of soft tissue management is emphasized, and approaches to internal orbital reconstruction are discussed. While evidence remain limited, intraoperative imaging and navigation may prove to be useful adjuncts in the treatment of zygomaticomaxillary fractures.

Technical Note on Three- and Four-Wall Orbital Reconstructions with Patient-Specific Implants

ABSTRACT

Orbital reconstruction is one of the most complex procedures in maxillofacial surgery. It becomes even more complex when all references to the original anatomy are lost. The purpose of this article is to provide an overview of techniques for complex three- and four-wall orbital reconstructions. Preoperative virtual surgical planning is essential when considering different reconstruction possibilities. The considerations that may lead to different approaches are described, and the advantages and drawbacks of each technique are evaluated. It is recommended to reconstruct solitary three-wall or four-wall orbital defects with multiple patient-specific implants. Optimizations of this treatment protocol are suggested, and their effects on predictability are demonstrated in a case presentation of a four-wall defect reconstruction with multiple patient-specific implants.

Advances in the Resection and Reconstruction of Midfacial Tumors Through Computer Assisted Surgery

Curatively intended oncologic surgery is based on a residual-free tumor excision. Since decades, the surgeon’s goal of R0-resection has led to radical resections in the anatomical region of the midface because of the three-dimensionally complex anatomy where aesthetically and functionally crucial structures are in close relation. In some cases, this implied aggressive overtreatment with loss of the eye globe. In contrast, undertreatment followed by repeated re-resections can also not be an option. Therefore, the evaluation of the true three-dimensional tumor extent and the intraoperative availability of this information seem critical for a precise, yet substance-sparing tumor removal. Computer assisted surgery (CAS) can provide the framework in this context. The present study evaluated the beneficial use of CAS in the treatment of midfacial tumors with special regard to tumor resection and reconstruction. Therefore, 60 patients diagnosed with a malignancy of the upper jaw has been treated, 31 with the use of CAS and 29 conventionally. Comparison of the two groups showed a higher rate of residual-free resections in cases of CAS application. Furthermore, we demonstrate the use of navigated specimen taking called tumor mapping. This procedure enables the transparent, yet precise documentation of three-dimensional tumor borders which paves the way to a more feasible interdisciplinary exchange leading e.g. to a much more focused radiation therapy. Moreover, we evaluated the possibilities of primary midface reconstructions seizing CAS, especially in cases of infiltrated orbital floors. These cases needed reduction of intra-orbital volume due to the tissue loss after resection which could be precisely achieved by CAS. These benefits of CAS in midface reconstruction found expression in positive changes in quality of life. The present work was able to demonstrate that the area of oncological surgery of the midface is a prime example of interface optimization based on the sensible use of computer assistance. The fact that the system makes the patient transparent for the surgeon and the procedure controllable facilitates a more precise and safer treatment oriented to a better outcome.

Application of Patient-Specific Implants as Alternative Approach to Zygoma Defect Management - A Retrospective Study

Introduction:

Zygoma defects are a challenging clinical problem and are frequently connected with the alteration of facial harmony, horizontal asymmetry of the face, and significant functional deficit. The application of patient-specific implants (PSIs) has the potential to improve the effectiveness of zygoma defect management. The aim of this study was to evaluate the anatomic, esthetic, and functional outcomes of PSI application for zygoma reconstruction.

Materials and Methods:

A retrospective study was conducted on data from 11 patients with zygoma defects who underwent a reconstruction procedure in which a PSI was applied and was followed for >1 year after surgery with the evaluation of esthetic and functional outcomes. Precision of PSI position and anatomy reconstruction was estimated by superimposition of the models with automatic point-to-point measurement and determination of the existing deviations between models.

Results:

The mean follow-up period in our study was 21.6 ± 6.2 months (range 14–39 months). No major complications occurred in the postoperative period: There were no clinical or computed tomography symptoms of maxillary sinusitis, implant-related infection, or implant exposure. The mean deviation between the planned and real positions of PSIs in our series was 0.72 ± 0.41 mm. The mean deviation between the reconstructed zygomatic complex and the mirrored intact side in our series was 1.45 ± 0.7 mm. The mean volume difference between the intact and damaged orbits was 1.7 ± 0.8 mm³.

Discussion:

The results of the present study support the wider clinical application of PSIs in orbital and zygoma reconstructions, as it is an effective option to achieve precise reconstruction of the complex zygoma anatomy.

[Complex reconstructions in the facial and cranial regions]

Posttraumatic reconstruction of the neurocranium and viscerocranium is an essential part of modern oral and maxillofacial surgery, in addition to oncological surgery, surgery of congenital craniofacial deformities and dental surgery. Due to the complex anatomy of the facial skull and significant esthetic and functional demands on its reconstruction, reconstructive trauma surgery in this area places the highest demands on the surgeon. This is all the more true if definitive craniomaxillofacial surgical treatment can sometimes only be performed with considerable delays for the benefit of other life-threatening injuries. In order to take these prerequisites into account, achievements of modern biomedical technology, such as intraoperative real-time navigation, computer-assisted planning and computer-assisted manufacturing (CAD/CAM) of patient-specific biomodels and implants, came up early for use in oral and maxillofacial surgery. In combination with intraoperative three-dimensional imaging, these methods result in a treatment pathway tailored to the individual patient, which is directly checked for quality at every step and thus ensures the best possible result for the patient. The use of these technologies extends far beyond the original indications in the area of orbital reconstruction and restoration of bony defects with simple geometry, such as skull defects. Nowadays, even the most complex pan-facial fractures can be restored esthetically and functionally by means of digitalized preliminary planning and individualized skull, orbital and zygomatic implants as well as total temporomandibular joint prostheses.

Accuracy of free-hand positioned patient specific implants (PSI) in primary reconstruction after inferior and/or medial orbital wall fractures

BACKGROUND

To assess the accuracy with which CAD/CAM-fabricated patient-specific titanium implants (PSI) are positioned for inferior and/or medial orbital wall reconstruction without the use of intraoperative navigation.

METHODS

Patients who underwent a primary reconstruction of the orbital walls with PSI due to fractures were enrolled in this retrospective cohort analysis. The primary outcome variables were the mean surface distances (MSD) between virtually planned and postoperative PSI position and single linear deviations in the x-, y- and z-axis at corresponding reference points. Secondary outcome variables included demographic data, classification of orbital wall defects and clinical outcomes.

RESULTS

A total of 33 PSI (orbital floor n = 22; medial wall, n = 11) were examined in 27 patients. MSD was on a comparable level for the orbital floor and medial wall (median 0.39 mm, range 0.22-1.53 mm vs. median 0.42 mm, range 0.21-0.98 mm; p = 0.56). Single linear deviations were lower for reconstructions of the orbital floor compared to the medial wall (median 0.45 vs. 0.79 mm; p < 0.05). There was no association between the occurrence of diplopia and the accuracy level (p = 0.418).

CONCLUSIONS

Free-hand positioning of PSI reaches a clinically appropriate level of accuracy, limiting the necessity of navigational systems to selected cases.

Functional and Cosmetic Outcome after Reconstruction of Isolated, Unilateral Orbital Floor Fractures (Blow-Out Fractures) with and without the Support of 3D-Printed Orbital Anatomical Models

The present study aimed to analyze if a preformed "hybrid" patient-specific orbital mesh provides a more accurate reconstruction of the orbital floor and a better functional outcome than a standardized, intraoperatively adapted titanium implant. Thirty patients who had undergone surgical reconstruction for isolated, unilateral orbital floor fractures between May 2016 and November 2018 were included in this study. Of these patients, 13 were treated conventionally by intraoperative adjustment of a standardized titanium mesh based on assessing the fracture's shape and extent. For the other 17 patients, an individual three-dimensional (3D) anatomical model of the orbit was fabricated with an in-house 3D-printer. This model was used as a template to create a so-called "hybrid" patient-specific titanium implant by preforming the titanium mesh before surgery. The functional and cosmetic outcome in terms of diplopia, enophthalmos, ocular motility, and sensory disturbance trended better when "hybrid" patient-specific titanium meshes were used but with statistically non-significant differences. The 3D-printed anatomical models mirroring the unaffected orbit did not delay the surgery's timepoint. Nonetheless, it significantly reduced the surgery duration compared to the traditional method (58.9 (SD: 20.1) min versus 94.8 (SD: 33.0) min, p-value = 0.003). This study shows that using 3D-printed anatomical models as a supporting tool allows precise and less time-consuming orbital reconstructions with clinical benefits.

Accuracy of Patient-Specific Meshes as a Reconstruction of Orbital Floor Blow-Out Fractures

ABSTRACT

Computer-aided design and manufacturing (CAD-CAM)-based techniques are developing fast in facial reconstruction and osteosynthesis. Patient-specific implant (PSI) production is already sufficiently fast for everyday use and can be utilized even for primary trauma surgery such as orbital floor reconstruction after blowout fracture. Purpose of our study is to retrospectively analyze the 3-dimensional (3D) success of PSI reconstructions of orbital floor fractures in our unit. The authors analyzed retrospectively a 1-year cohort (n = 8) of orbital floor blow-out fractures that have been reconstructed using virtual surgical plan and CAD-CAM PSI. Postoperative computed topographies of patients were compared to their original virtual surgical plans. The 3D outcome and fitting of the PSI was good in all patients. Mean error for 3D position of the PSI was 1.3 to 1.8 mm (range 0.4 to 4.8 mm) and postoperative orbital volume was successfully restored in all of the patients. Use of CAD-CAM PSI for reconstruction of orbital floor blow out fracture is reliable method and thus recommended.

Patient-Specific Implants in Oculofacial Plastic Surgery

PURPOSE

To investigate how patient-specific implants (PSIs) are being utilized for periocular facial skeletal reconstruction. Specifically, to characterize indications for custom implants, areas of reconstruction, intraoperative variables impacting implant placement, as well as to report on postoperative outcomes.

MATERIALS AND METHODS

A retrospective chart review was performed for patients who received a PSI for periocular skeletal reconstruction between 2015 and 2019. Three independent academic centers were included in this study, which encompassed 4 different primary surgeons. Medical records, radiographic imaging, and operative reports were reviewed.

RESULTS

Eleven patients, 8 females and 3 males, ages ranging from 15 to 63 years old received PSIs. The average duration of follow up was 16 months ± 6.6 months (range: 9-30 months). The most common underlying etiology for reconstruction was prior trauma (54.5%) followed by benign tumor resection (18.2%). The most frequent area of reconstruction involved the inferior orbital rim and adjacent maxilla (63.6%). Implant materials included porous polyethylene, polyetheretherketone, and titanium. Six implants required intraoperative modification, most commonly accommodate critical neurovascular structures (66.6%) or improve contour (33.3%). Two postoperative complications were noted, both in the form of infection with 1 implant requiring removal.

CONCLUSIONS

Reconstruction of complex facial skeletal defects can be achieved by utilizing computer-assisted design software and 3D printing techniques to create PSIs. These implants represent the most customizable option for symmetric restoration of the facial skeleton by not only addressing structural deficits but also volumetric loss. This was particularly apparent in reconstruction of the orbital rim and midface. PSIs were found to be of most benefit in patients with prior trauma or complex skeletal defects after tumor resection.

Implant malposition and revision surgery in primary orbital fracture reconstructions

The aim of the study was to assess factors leading to revision surgery and implant position of primary orbital fracture reconstructions. A retrospective cohort included patients who underwent orbital floor and/or medial wall fracture reconstruction for recent trauma. Demographics, fracture type, surgery and implant-related variables, and postoperative implant position were analyzed. The overall revision surgery rate was 6.5% (15 of 232 surgeries). The rate was highest in combined midfacial fractures with rim involvement (14.0%), lower in zygomatico-orbital fractures (8.7%), and lowest in isolated blowout fractures (3.8%). Fracture type, orbital rim fixation and implant malposition predicted revision. The best positioning was achieved with patient-specific milled titanium implants (mtPSI) and resorbable materials, whereas the poorest with preformed three-dimensional titanium plates. Combined midfacial fractures with rim involvement in particular have a high risk for orbital revision surgery. Within the limitations of the present study, mtPSIs should be preferred in the reconstruction of primary orbital fractures if possible.

Comparison of additive manufactured models of the mandible in accuracy and quality using six different 3D printing systems

The aim of this study was to analyze and compare the accuracy and quality of six 3D printing systems available on the market. Data acquisition was performed with 12 scans of human mandibles using an industrial 3D scanner and saved in STL format. These STL files were printed using six different printing systems. Previously defined distances were measured with a sliding caliper on the 72 printed mandibles. The printed models were then scanned once again. Measurements of volumes and surfaces for the STL files and the printed models were compared. Accuracy and quality were evaluated using industrial software. An analysis of the punctual aberration between the template and the printed model, based on a heat map, was also carried out. Secondary factors, such as costs, production times and expendable materials, were also examined. All printing systems performed well in terms of accuracy and quality for clinical usage. The Formiga P110 and the Form 2 showed the best results for volume, with average aberrations of 0.13 ± 0.23 cm³ and 0.12 ± 0.17 cm³, respectively. Similar results were achieved for the heat map aberration, with values of 0.008 ± 0.11 mm (Formiga P110) and 0.004 ± 0.16 mm (Form 2). Both printers showed no significant difference from the optimal neutral line (Formiga P110, p = 0.15; Form 2, p = 0.60). The cheapest models were produced by the Ultimaker 2+, with an average of 5€ per model, making such desktop printers affordable for rapid prototyping. Meanwhile, advanced printing systems with sterilizable and biocompatible printing materials, such as the Formiga P110 and the Form 2, fulfill the high expectations for maxillofacial surgery.