Patient-specific puzzle implant preformed with 3D-printed rapid prototype model for combined orbital floor and medial wall fracture

Towards Precision Ophthalmology: The Role of 3D Printing and Bioprinting in Oculoplastic Surgery, Retinal, Corneal, and Glaucoma Treatment

In the forefront of ophthalmic innovation, biomimetic 3D printing and bioprinting technologies are redefining patient-specific therapeutic strategies. This critical review systematically evaluates their application spectrum, spanning oculoplastic reconstruction, retinal tissue engineering, corneal transplantation, and targeted glaucoma treatments. It highlights the intricacies of these technologies, including the fundamental principles, advanced materials, and bioinks that facilitate the replication of ocular tissue architecture. The synthesis of primary studies from 2014 to 2023 provides a rigorous analysis of their evolution and current clinical implications. This review is unique in its holistic approach, juxtaposing the scientific underpinnings with clinical realities, thereby delineating the advantages over conventional modalities, and identifying translational barriers. It elucidates persistent knowledge deficits and outlines future research directions. It ultimately accentuates the imperative for multidisciplinary collaboration to enhance the clinical integration of these biotechnologies, culminating in a paradigm shift towards individualized ophthalmic care.

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

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

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.

A Literature Review of Rapid Prototyping and Patient Specific Implants for the Treatment of Orbital Fractures

Post-traumatic reconstruction of the orbit can pose a challenge due to inherent intraoperative problems. Intra-orbital adipose tissue is difficult to manipulate and retract making visualization of the posterior orbital contents difficult. Rapid prototyping (RP) is a cost-effective method of anatomical model production allowing the surgeon to produce a patient specific implant (PSI) which can be pre-surgically adapted to the orbital defect with exact reconstruction. Intraoperative imaging allows immediate assessment of reconstruction at the time of surgery. Utilization and combination of both technologies improves accuracy of reconstruction with orbital implants and reduces cost, surgical time, and the rate of revision surgery.

3D Printing in Eye Care

Three-dimensional printing enables precise modeling of anatomical structures and has been employed in a broad range of applications across medicine. Its earliest use in eye care included orbital models for training and surgical planning, which have subsequently enabled the design of custom-fit prostheses in oculoplastic surgery. It has evolved to include the production of surgical instruments, diagnostic tools, spectacles, and devices for delivery of drug and radiation therapy. During the COVID-19 pandemic, increased demand for personal protective equipment and supply chain shortages inspired many institutions to 3D-print their own eye protection. Cataract surgery, the most common procedure performed worldwide, may someday make use of custom-printed intraocular lenses. Perhaps its most alluring potential resides in the possibility of printing tissues at a cellular level to address unmet needs in the world of corneal and retinal diseases. Early models toward this end have shown promise for engineering tissues which, while not quite ready for transplantation, can serve as a useful model for in vitro disease and therapeutic research. As more institutions incorporate in-house or outsourced 3D printing for research models and clinical care, ethical and regulatory concerns will become a greater consideration. This report highlights the uses of 3D printing in eye care by subspecialty and clinical modality, with an aim to provide a useful entry point for anyone seeking to engage with the technology in their area of interest.

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.

Custom Interlocking Implants for Primary and Secondary Reconstruction of Large Orbital Floor Defects: Case Series and Description of Workflow

Large fractures of the orbital floor present several technical challenges for the craniomaxillofacial surgeon. One major challenge is limited surgical access as it pertains to the adaption of a large implant within the confines of a small incision. Transfacial approaches or techniques to extend the incision may improve access but have the potential drawback of creating unesthetic scars, nerve injury, and lid contracture. In this series we present a novel solution combining virtual surgical planning and the use of a 2 piece, interlocking patient specific implant to address the problem of limited surgical access.

Comparison of Nasoseptal Cartilage Graft Versus Titanium Mesh in Reconstruction of Pure Orbital Blowout Fractures

PURPOSE

To compare the efficacy of nasoseptal cartilage grafts versus titanium mesh implants in pure orbital blowout fractures.

METHODS

A retrospective review was performed on 48 patients who had surgical repair of an orbital fracture. Patients who underwent pure orbital blowout fracture repair with either nasoseptal cartilage grafts or titanium mesh implants and at least 1 year postoperative follow-up were included in the study. The clinical features and treatment outcomes were analyzed.

RESULTS

Twenty-five patients fulfilled our study criteria and were included in the analyses. Nasoseptal graft was used in 12 patients (48%) while titanium mesh was preferred in 13 patients (52%). Preoperative clinical features including age, size of the floor defect, and preoperative clinical findings (enophthalmos, diplopia, and restriction of ocular motility) were similar between 2 groups. Mean postoperative follow-up was 14.7 ± 2.3 months in the nasoseptal group while it was 16.1 ± 2.5 months in the titanium group (P = 0.84). Diplopia and ocular motility limitation were resolved in all patients at the last postoperative follow-up visit, while 1 patient in each group had enophthalmos (8.3% versus 7.6%, P = 1.0). No patient in the nasoseptal group experienced postoperative complications while 2 patients in the titanium group (15.3%) developed material-related complications (P = 0.48).

CONCLUSIONS

Long-term clinical results of nasoseptal cartilage grafts and titanium mesh implants in pure orbital blowout fractures with preoperative floor defects smaller than 4 cm2 were comparable. Nasoseptal cartilage grafts may be preferred in patients with septal deviation and no spurs or turbinate hypertrophy.

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.

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

BACKGROUND

Orbital blowout fracture reconstruction often requires an implant, which must be shaped at the time of surgical intervention. This process is time-consuming and requires multiple placement trials, possibly risking complications. Three-dimensional printing technology has enabled health care facilities to generate custom anatomical models to which implants can be molded to precisely match orbital anatomy. The authors present their early experience with these models and their use in optimizing orbital fracture fixation.

METHODS

Maxillofacial computed tomographic scans from patients with orbital floor or wall fractures were prospectively obtained and digitally reconstructed. Both injured-side and mirrored unaffected-side models were produced in-house by stereolithography printing technique. Models were used as templates for molding titanium reconstruction plates, and plates were implanted to reconstruct the patients' orbital walls.

RESULTS

Nine patients (mean age, 15.5 years) were included. Enophthalmos was present in seven patients preoperatively and resolved in six patients with surgery. All patients had excellent conformation of the implant to the fracture site on postoperative computed tomographic scan. Postoperative fracture-side orbital volumes were significantly less than preoperative, and not significantly different from unfractured-side orbital volumes. Total model preparation time was approximately 10 hours. Materials cost was at most $21. Plate bending time was approximately 60 seconds.

CONCLUSIONS

Patient-specific orbital models can speed the shaping of orbital reconstruction implants and potentially improve surgical correction of orbital fractures. Production of these models with consumer-grade technology confers the same advantages as commercial production at a fraction of the cost and time.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Reconstruction of Combined Orbital Floor and Medial Wall Fractures Using Custom-Made Titanium Alloy Implant

ABSTRACT

The reconstruction of combined orbital floor and medial wall fractures is challenging due to the surgical approach and implant stability. A 0.5 mm thickness rigidity custom made titanium alley implant was created by 3-dimensional printing with electron-beam additive manufacturing. The implant was designed to cover the entire surface of the inferomedial orbit based on the flipped the contralateral orbit images. Although the cost was expensive, the use of three-dimensional printed implants for extensive orbital wall fractures was useful for decreasing operative time, and can be accessed with a limited surgical approach with a precise fit.

Treatment of orbital blowout fracture using a customized rigid carrier

PURPOSE

This study aimed to examine the usefulness of treating orbital blowout fracture using a customized rigid carrier.

MATERIAL AND METHODS

Patients who underwent surgery for orbital blowout fractures in our department from April 2016 to March 2019 were recruited in the study. We molded a rigid thermoplastic material into the same shape as the reconstruction material according to the 3D model and transplanted it into the orbital space along with the reconstruction material. We assessed Hertel exophthalmometry, awareness of diplopia, and the Hess area ratio (HAR%).

RESULTS

We performed this procedure in 15 patients with blowout fractures. Reconstruction materials used were iliac bone, absorbable plates, and titanium mesh in 12, 2, and 1 patient, respectively. None of the patients showed a difference of more than 2 mm on Hertel exophthalmometry. Only one patient had diplopia after surgery. The average preoperative and postoperative HAR% were 83.1 and 90.6, respectively. HAR% was more than 85% in 6 of 7 postoperative cases.

CONCLUSIONS

This method can be applied for surgery using various reconstructive materials and can be a useful method, especially in patients with a wide range of orbital bone defects.

Overview of tools for the measurement of the orbital volume and their applications to orbital surgery

There are numerous applications in craniofacial surgery with orbital volume (OV) modification. The careful management of the OV is fundamental to obtain good esthetic and functional results in orbital surgery. With the growth of computer-aided design - computer-aided manufacturing (CAD-CAM) technologies, patient-specific implants and custom-made reconstruction are being used increasingly. The precise measurement of the OV before surgery is becoming a necessity for craniofacial surgeons. There is no consensus on orbital volume measurements (OVMs). Manual segmentation of computed tomography (CT) images is the most used method to determine the OV, but it is time-consuming and very sensitive to operator errors. Here, we describe the various methods of orbital volumetry validated in the literature that can be used by surgeons in preoperative planning of orbital surgery. We also describe the leading software employed for these methods and discuss clinical use (posttraumatic enophthalmos prediction and orbital reconstruction) in which OVMs are important.

Analysis of Orbital Morphology and its Relationship With Eyelid Morphology

Correct anatomical reconstruction of the orbital wall for function and cosmesis is important; however, this is difficult because of the structure's complexity. The authors aimed to analyze and classify orbital morphology from computed tomography (CT) images and examine the relationship between orbital morphology and eyelid morphology in the Japanese population. CT images of 60 men (right side, 29; left side, 31) and 44 women (each side, 22) were included. The lengths of the orbital medial wall and floor in the coronal plane at the anterior, middle, and posterior planes of the orbit; angle between them; simotic index; and the thickness of upper eyelid were measured. Additionally, the presence or absence of double eyelids was evaluated. Non-paired Student's t test and Pearson correlation coefficient test were used for analysis. Orbital morphology was symmetrical on both sides, and men had a larger orbit than women. Orbital morphology was classified into 2 groups according to the posterior angle, and there was a difference between the groups in the simotic index. The difference between groups may represent a genetic difference between the Jomon and Yayoi people and not only provide a new classification for the orbit of the population but also be useful in orbital reconstruction.

Functional and Aesthetic Outcome of Extensive Orbital Floor and Medial Wall Fracture via Navigation and Endoscope-assisted Reconstruction

BACKGROUND AND PURPOSE

Extensive orbital floor and medial wall fractures compared with isolated orbital wall fractures are more likely to require surgical correction because of a higher possibility of complications like diplopia, enophthalmos, or numbness. The unique and complex contours of the orbital anatomy limit the intraoperative view of the intraorbital anatomy, and complex orbital fractures involving the buttress of the transition zone area all make orbital reconstruction surgery more challenging. The aim of this study was to describe our experience with surgical approaches using navigation- and endoscope-assisted guidance for extensive orbital floor and medial wall fracture reconstruction.

PATIENTS AND METHODS

A retrospective study was conducted on consecutive 17 patients from 2015 to 2017 presenting with unilateral extensive orbital floor and medial wall fractures at the Chang Gung Memorial Hospital, Linkou Branch. The fractures were treated surgically with a preformed mesh plate and layered Medpor (Porex Surgical Inc, Atlanta, Ga) through navigation and endoscopy. The preoperative and postoperative functional and aesthetic outcomes were described.

RESULTS

All extensive orbital floor and medial wall fractures were successfully reconstructed. Of the 17 patients, 11 experienced diplopia preoperatively, and for 2 of the 11 patients, diplopia improved immediately after surgery. In the remaining 9 patients, diplopia still persisted after surgery; however, diplopia recovered after an average of 3.44 months (range, 1-9 months). Average enophthalmos among the 10 patients, evaluated by postoperative follow-up computed tomography scan, improved from 2.99 to 0.68 mm. There were no major complications during follow-up, and all patients were satisfied with their final appearance and function.

CONCLUSIONS

On the basis of the results, our surgical approach using preformed titanium mesh plates and Medpor under the assistance of navigation and endoscopy can be a safe, accurate, and effective method for the management of extensive orbital floor and medial wall fractures and clearly optimizes functional and aesthetic outcomes.

3D titanium implant for orbital reconstruction after maxillectomy

The surgical treatment of maxillary tumours often consists of an open subtotal or total maxillectomy with a subsequent significant defect. Reconstruction is, therefore, a major challenge for head and neck surgeons. Along with 3D printing development, titanium pre-bent implants have been created for orbital wall and floor reconstruction. The aim of this study was to evaluate the post-operative tolerance of these implants in patients who had undergone this procedure in our department. Implant tolerance was the primary endpoint, evaluated by whether or not surgery was required for infection or extrusion 6 months after the procedure. The secondary endpoints were satisfactory functional and aesthetic characteristics of the reconstruction as well as the quality of life. Eleven patients underwent a maxillectomy with orbital floor resection for tumours and reconstruction using the titanium PorousiTi® (Materialise®, Leuven, Belgium) implant beginning in 2013 in Lariboisière Hospital, Paris. The mean follow-up time was 17 months (range, 6-34). During the follow-up period, two patients (n = 2/11; 18.2%) were operated again for implant extrusion and exposure through the skin 1 month later or during their radiotherapy course. During the follow-up period, no post-operative infection occurred in any of the patients. In our experience, the implant was well-tolerated with few post-operative complications and satisfactory aesthetic and functional results.

Clinical Application of a Specific Simulation Software for 3-Dimensional Orbital Volume Modeling for Orbital Wall Reconstruction

In this study, we developed a new 3-dimensional (3D) preoperative planning software and investigated its effectiveness by measuring orbital volume change. Fifty-six patients who underwent unilateral orbital wall reconstruction between December 2015 and February 2018 in our institute were recruited. We developed an orbit-specific automatic 3D modeling software (Osteopore CMF 3D) that can automatically detect orbital fracture site, process mirroring, measure volume, and then produce a customized orbital implant. Using preoperative and postoperative 3D computed tomography, orbital volume was measured and compared between Osteopore CMF 3D and the widely used Mimics. Intraclass correlation coefficient between Osteopore CMF 3D and Mimics showed 90.6% concordance for preoperative injured site orbital volume and 86.7% concordance for postoperative orbital volume, both being statistically significant (preoperative intraclass correlation coefficient, 0.906 [confidence interval {CI}, 0.840-0.945; P < 0.000]; postoperative intraclass correlation coefficient, 0.867 [CI, 0.773-0.922; P < 0.000]). For uninjured sites, the 2 software packages showed 76.6% preoperative concordance and 83.9% postoperative concordance, both being statistically significant (preoperative intraclass correlation coefficient, 0.766 [CI, 0.600-0.863; P < 0.000]; postoperative intraclass correlation coefficient, 0.839 [CI, 0.725-0.905; P < 0.000]). This study introduces our newly developed 3D surgical planning software specialized for orbital wall reconstruction and demonstrates its performance to be comparable with that of a widely used software.