Clinical application of automated virtual orbital reconstruction for orbital fracture management with patient-specific implants: A prospective comparative study

Orbital Patient-Specific (Customized) Implants: A Report by the American Academy of Ophthalmology

PURPOSE

To review systematically the literature on the efficacy and safety of the use of patient-specific implants (PSIs) in orbital reconstructive surgery.

METHODS

A literature search was last conducted in January 2025 in the PubMed database for English language original research that assessed the use of any PSI reported for orbital reconstructive surgery. Of the 219 articles identified, 51 met the inclusion criteria for this assessment and were selected for full-text review and data abstraction. A total of 19 studies met the study criteria, and the panel methodologist assigned a level III rating to each study.

RESULTS

No study met the criteria for level I or II evidence. Eight of the 19 studies compared a PSI group with a control group (other forms of implants such as preformed, prebent sheets)-5 studies involved acute fracture repair and 3 involved a mixture of acute, delayed, or revision surgery. The remaining 11 studies did not have a comparison group, and indications included acute fracture repair (n = 2), delayed or secondary fracture repair (n = 3), or an after-tumor resection (n = 5). One study compared outcomes using PSIs designed using automated software with PSIs designed manually. Patient-specific implant material included titanium (n = 12), polyether ether ketone (PEEK) (n = 3), porous polyethylene (n = 2), and ceramic (n = 2). Time to manufacture implants ranged from 1 to 35 days, with most under 10 days. Volumetric analysis generally reported greater improvement in postoperative orbital volume for PSIs compared with non-PSIs. Clinical improvement in diplopia, enophthalmos, and extraocular motility was variably reported and largely not statistically analyzed or significant. Complications were variably reported and included expected complications after orbital fracture repair.

CONCLUSIONS

The existing literature on PSIs for orbital surgery contains a heterogeneity of indications, designs, materials, and reporting. Because all studies met level III criteria for evidence, definitive conclusions were limited. Although anecdotal and low-quality evidence reports showed possible improved outcomes with PSIs compared with non-PSIs, determination of the best applications, designs, outcomes, and safety will require well-designed prospective studies with sufficient postoperative follow-up and outcome metrics.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Efficacy of 3D-printed patient specific implant for orbital wall fracture repair in a series of 40 patients

This study was aimed to evaluate the efficacy of a 3D-printed patient specific implant (PSI) made of polycaprolactone (PCL) in repairing orbital wall fractures. We retrospectively reviewed patients who underwent surgical repair for unilateral orbital wall fractures using a 3D-printed PCL PSI. Computed tomography scans were used to compare the orbital tissue volumes and the morphological similarity (root-mean-square [RMS] conformance distance) between the fractured wall and the mirrored counterpart before and after surgery. All orbital fractures (inferior wall, 19; medial wall, 9; and combined inferior and medial walls, 12) were successfully repaired without postoperative complications. The mean time for implant insertion during surgery was 19.8 s (range, 3-60). The mean orbital tissue volume ratio between the fractured orbit and the contralateral normal orbit significantly decreased after surgery (109.0% preoperatively vs. 100.6% at postoperative 6 months, P < 0.001, paired t-test). The median RMS conformance distance significantly decreased after surgery (3.426 mm preoperatively vs. 1.073 mm at postoperative 6 months, P < 0.001, Wilcoxon signed-rank test). Our findings suggest that using a 3D-printed PCL PSI could effectively restore the original volume and shape of the orbit, thus being a valuable addition to the surgeon's armamentarium for managing orbital wall fractures.

Intelligent surgical planning for automatic reconstruction of orbital blowout fracture using a prior adversarial generative network

Orbital blowout fracture (OBF) is a disease that can result in herniation of orbital soft tissue, enophthalmos, and even severe visual dysfunction. Given the complex and diverse types of orbital wall fractures, reconstructing the orbital wall presents a significant challenge in OBF repair surgery. Accurate surgical planning is crucial in addressing this issue. However, there is currently a lack of efficient and precise surgical planning methods. Therefore, we propose an intelligent surgical planning method for automatic OBF reconstruction based on a prior adversarial generative network (GAN). Firstly, an automatic generation method of symmetric prior anatomical knowledge (SPAK) based on spatial transformation is proposed to guide the reconstruction of fractured orbital wall. Secondly, a reconstruction network based on SPAK-guided GAN is proposed to achieve accurate and automatic reconstruction of fractured orbital wall. Building upon this, a new surgical planning workflow based on the proposed reconstruction network and 3D Slicer software is developed to simplify the operational steps. Finally, the proposed surgical planning method is successfully applied in OBF repair surgery, verifying its reliability. Experimental results demonstrate that the proposed reconstruction network achieves relatively accurate automatic reconstruction of the orbital wall, with an average DSC of 92.35 ± 2.13% and a 95% Hausdorff distance of 0.59 ± 0.23 mm, markedly outperforming the compared state-of-the-art networks. Additionally, the proposed surgical planning workflow reduces the traditional planning time from an average of 25 min and 17.8 s to just 1 min and 35.1 s, greatly enhancing planning efficiency. In the future, the proposed surgical planning method will have good application prospects in OBF repair surgery.

Re-establishing Facial Aesthetics - Patient-specific Orbital Implant for Post-traumatic Deformity

Rationale

Complex fractures of the maxillofacial region can require staged interventions to achieve optimal outcomes. A significant example of this are complex fractures of the orbital floor, which may be difficult to restore during primary treatment. The secondary correction is often required which can be using stock- or customised implants.

Patient Concerns

A previously operated case of panfacial trauma presented with an aesthetic concern regarding the asymmetrical appearance of his eyes.

Diagnosis

On clinical and radiological evaluation, the patient was diagnosed with enophthalmos of the left eye secondary to orbital floor fracture.

Treatment

A patient-specific implant (PSI) was fabricated and placed for orbital floor reconstruction.

Outcomes

Postoperatively, aesthetic and functional outcomes were satisfactory.

Take-away Lessons

This case report highlights the use of PSIs in orbital floor reconstruction, made possible due to the advent of virtual surgical planning and three-dimensional printing in the field of oral and maxillofacial surgery.

Automated 3-D Computer-Aided Measurement of the Bony Orbit: Evaluation of Correlations among Volume, Depth, and Surface Area

(1)The study aimed to measure the depth, volume, and surface area of the intact human orbit by applying an automated method of CT segmentation and to evaluate correlations among depth, volume, and surface area. Additionally, the relative increases in volume and surface area in proportion to the diagonal of the orbit were assessed. (2) CT data from 174 patients were analyzed. A ball-shaped mesh consisting of tetrahedral elements was inserted inside orbits until it encountered the bony boundaries. Orbital volume, area depth, and their correlations were measured. For the validation, an ICC was used. (3) The differences between genders were significant (p < 10-7) but there were no differences between sides. When comparing orbit from larger to smaller, a paired sample t-test indicated a significant difference in groups (p < 10-10). A simple linear model (Volume~1 + Gender + Depth + Gender:Depth) revealed that only depth had a significant effect on volume (p < 10-19). The ICCs were 1.0. (4) Orbital volume, depth, and surface area measurements based on an automated CT segmentation algorithm demonstrated high repeatability and reliability. Male orbits were always larger on average by 14%. There were no differences between the sides. The volume and surface area ratio did not differ between genders and was approximately 0.75.

Clinical and radiographic assessment of patient-specific transantral reconstruction of orbital floor fractures: A case series

To clinically and radiographically evaluate patient-specific titanium meshes via a trans-antral approach for correction of enophthalmos and orbital volume in patients with recent unilateral orbital floor fracture. Seven patients with unilateral orbital floor fractures received patient-specific titanium meshes that were designed based on a mirror-image of the contralateral intact orbit. The patient-specific implants (PSIs) were inserted via a trans-antral approach without endoscopic assistance. The patients were evaluated clinically for signs of diplopia and restricted gaze as well as radiographically for enophthalmos and orbital volume correction. Diplopia was totally resolved in two of the three patients who reported diplopia in the upward gaze. Whereas enophthalmos significantly improved in all but two patients, with a mean value of 0.2229 mm postoperatively compared to 0.9914 mm preoperatively. CT scans showed excellent adaptation of the PSIs to the orbital floor with a mean reduction of the orbital volume from 29.59 cc to 27.21 cc, a mean of 0.6% smaller than the intact orbit. It can be concluded that the proposed PSI can offer good reconstruction of the orbital floor through an isolated intraoral transantral approach with minimal complications. It could of special benefit in extensive orbital floor fractures.

Efficacy and feasibility of a forehead flap surgical guide for nasal reconstruction

For successful nasal reconstruction using a forehead flap, three-dimensional (3D) nasal defects need to be translated into a two-dimensional (2D) forehead surface. For this study, a patient-specific 3D-printed forehead flap guide that could precisely translate a virtually simulated nasal shape into a 2D flap template was developed. The study aimed to evaluate the feasibility and efficacy of a 3D-printed forehead flap guide for nasal reconstructions. The 3D nasal surface was scanned using a 3D camera, and a 'digital clay' process was performed to correct the nasal deformity. The 3D morphology was flattened into a 2D forehead flap guide. The guide was 3D-printed and used for the forehead flap design. Photographic records were used to conduct anthropometric and aesthetic evaluations. Between October 2016 and August 2020, forehead flaps were performed using the forehead flap guide (guide group) and traditional templating method (control group) in 16 and 15 patients, respectively. The alar shape was more symmetric in the guide group than in the control group, with smaller right-to-left differences in alar width (p = 0.01) and height (p = 0.05). Regarding aesthetic evaluations, nose contour (p = 0.02) and nasal symmetry (p = 0.033) were better in the guide group than in the control group. The mean operative time was significantly shorter (91.9 ± 10.7 min) in the guide group than in the control group (116.4 ± 13.6 min) (p = 0.001). Our findings suggest that a 3D-printed forehead flap surgical guide can be effectively used in nasal reconstruction to reduce operative time and improve aesthetic outcomes.

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.

Augmented and Virtual Reality for Preoperative Trauma Planning, Focusing on Orbital Reconstructions: A Systematic Review

BACKGROUND

This systematic review summarizes recent literature on the use of extended reality, including augmented reality (AR), mixed reality (MR), and virtual reality (VR), in preoperative planning for orbital fractures.

METHODS

A systematic search was conducted in PubMed, Embase, Web of Science and Cochrane on 6 April 2023. The included studies compared extended reality with conventional planning techniques, focusing on computer-aided surgical simulation based on Computed Tomography data, patient-specific implants (PSIs), fracture reconstruction of the orbital complex, and the use of extended reality. Outcomes analyzed were technical accuracy, planning time, operative time, complications, total cost, and educational benefits.

RESULTS

A total of 6381 articles were identified. Four articles discussed the educational use of VR, while one clinical prospective study examined AR for assisting orbital fracture management.

CONCLUSION

AR was demonstrated to ameliorate the accuracy and precision of the incision and enable the better identification of deep anatomical tissues in real time. Consequently, intraoperative imaging enhancement helps to guide the orientation of the orbital reconstruction plate and better visualize the precise positioning and fixation of the PSI of the fractured orbital walls. However, the technical accuracy of 2-3 mm should be considered. VR-based educational tools provided better visualization and understanding of craniofacial trauma compared to conventional 2- or 3-dimensional images.

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.