Treatment with individual orbital wall implants in humans - 1-Year ophthalmologic evaluation

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.

Matrixmidface Preformed Orbital Implants for Three-Dimensional Reconstruction of Orbital Floor and Medial Wall Fractures: A Prospective Clinical Study

Study Design

Prospective Interventional study.

Objective

To evaluate the efficiency of Matrixmidface preformed Orbital plates for three-dimensional reconstruction of orbital floor and medial wall fractures.

Methods

This prospective institutional clinical study was conducted on a group of 14 patients who underwent repair of orbital floor and medial wall fracture defects using Matrixmidface Preformed Orbital plates and open reduction and internal fixation of associated fractures. The following parameters were studied preoperative and postoperative enophthalmos, hypoglobus, orbital volume; correction of diplopia, intraoperative and postoperative complications.

Results

All 14 patients were males aged between 19 and 42 years. The most common mode of injury was found to be road traffic accidents (RTAs) followed by self-fall and trauma at workplace. Orbital fractures were associated with other concomitant maxillofacial fractures in 12 patients (85.7%) while 2 patients (14.3%) had pure blowout fractures. Significant improvement of enophthalmos was noted from preoperative period to 1 week, 6 weeks, and 6 months postoperatively (P value .02, .01, and .01, respectively). Out of 11 patients with preoperative hypoglobus, 5 patients (45.45%) had persistent hypoglobus in the immediate postoperative period which reduced to 4 patients (36.36%) at 6 weeks postoperatively (p value .00). The postoperative orbital volume of fractured side ranged from 20.3 cm3 to 26.76 cm3 with a mean of 23.50 cm3 ± 1.74. The mean difference between the volumes of the repaired and uninjured sides was found to be .27 cm3 ± .39 (P value .02) denoting that the reconstruction of the orbit closely approximated that of the uninjured side.

Conclusions

The Matrixmidface Preformed Orbital plate provides exceptional reconstruction of the orbital blowout fracture defects and ensures satisfactory results clinically and radiographically. The plate ensures an approximate recreation of topographical anatomy of the orbit and adequately restores the orbital volume. It provides adequate correction of asymmetry, hypoglobus, enophthalmos and attempts to restore eye movements, without causing any significant postoperative complication.

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.

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.

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.

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.

Prebending of Prefabricated Orbital Implants: Towards Improved Orbital Angle Symmetry Post Craniofacial Trauma Surgery

PURPOSE

Reconstructive surgery after craniofacial trauma aim to restore orbital anatomy for function and aesthetic reasons. The purpose of this study is to improve postoperative orbital symmetry with the use of prebent prefabricated titanium implants.

METHODS

In this retrospective study, patients with combined unilateral medial wall and floor fractures who underwent orbital reconstruction surgery were selected. The angle of inferomedial orbital strut (AIOS) was measured at 3 standard locations on preoperative facial computed tomography guided scans of the nonfractured orbit in the coronal view and used as a guide to bend the prefabricated titanium implants intraoperatively. The corresponding values were measured on the postoperative computed tomography and compared for symmetry.

RESULTS

Out of 83 patients recruited for the study, 54 were in the prebent group while 29 were in the control group. All other demographics were similar among the 2 groups. Anterior AIOS has a difference of 4.9° between 2 orbits in the prebent group whereas a difference of 15.5° was noted in the nonprebent group. For middle AIOS, a difference of 4.7° was noted in the prebent group whereas nonprebent group had a difference of 14.1°. For posterior AIOS, the prebent group had a difference of 3.8° versus 14.1° in the nonprebent group. The difference in AIOS at all 3 points between the prebent and nonprebent group were significant.

CONCLUSIONS

Anatomical prefabricated titanium plates are versatile implants that facilitate orbital reconstruction. Prebending of these implants according to the fellow orbit can achieve better surgical outcomes in a cost-effective manner.

Detecting Binocular Diplopia in Orbital Floor Blowout Fractures: Superiority of the Orthoptic Approach

Background and Objectives: In patients with orbital floor blowout fracture (OFBF), accurate diagnosis of ocular motility disorder is important for decisions about conservative or surgical therapy. However, the accuracy of the traditional test for detecting binocular diplopia/ocular motility disorder using a moving pencil or finger (hereinafter, “finger test”) has been generally accepted as correct and has not been subject to scrutiny so far. Hence, its accuracy relative to full orthoptic examination is unknown. Materials and Methods: In this paper, the results of the “finger test” were compared with those derived from a complex examination by orthoptic tests (considered “true” value in patients with OFBF). Results: “Finger test” detected ocular motility disorder in 23% of patients while the full orthoptic examination proved much more efficient, detecting ocular motility disorder in 65% of patients. Lancaster screen test and test with color filters were the most important tests in the battery of the orthoptic tests, capable of identifying 97.7% and 95.3% of patients with ocular motility disorder, respectively. Still, none of the tests were able to correctly detect all patients with ocular motility disorder in itself. Conclusions: As the presence of ocular motility disorder/binocular diplopia is an important indication criterion for the surgical solution of the orbital floor blowout fracture, we conclude that a complex orthoptic evaluation should be always performed in these patients.

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.

Clinical outcome of patients with orbital fractures treated with patient specific CAD/CAM ceramic implants - A retrospective study

The aim of this study was to determine whether patients benefit from a secondary reconstruction since it carries the risks of no improvement or worsening of their current situation. Patients treated with individual computer-aided-design/computer-aided-manufacturing (CAD/CAM) ceramic implants were reviewed. To ascertain changes throughout the secondary reconstruction, the study investigators reviewed ophthalmological examinations, took volumetric measurements of the orbits and asked the patients for evaluation of their situation before and after the reconstruction. Points addressed were double vision, visual acuity, field of vision, limitations in daily life and aesthetic considerations. A total of 14 patients were reviewed and 11 answered the questionnaire. Ophthalmological examinations showed that the physical integrity of the eye was maintained. Volumetric measurements preopeatively (33.94 ± 3.24 cm³) and postoperatively (30.67 ± 2.07 cm³) showed that a statistically significant overcorrection of orbital volume leads to good functional and aesthetic outcomes. Patients' subjective opinions were that they greatly benefitted, especially concerning limitations in daily life, which improved by 4.4 ± 2.8 points out of 10 possible points, and aesthetics, with an improvement of 5.9 ± 1.78 points. Based on these findings, we conclude that secondary reconstructions contribute to improvement of the patients' quality of life and therefore should be considered as an option to improve patients' condition.

Custom-Made Zirconium Dioxide Implants for Craniofacial Bone Reconstruction

Reconstruction of the facial skeleton is challenging for surgeons because of difficulties in proper shape restoration and maintenance of the proper long-term effect. ZrO₂ implant application can be a solution with many advantages (e.g., osseointegration, stability, and radio-opaqueness) and lacks the disadvantages of other biomaterials (e.g., metalosis, radiotransparency, and no osseointegration) or autologous bone (e.g., morbidity, resorption, and low accuracy). We aimed to evaluate the possibility of using ZrO₂ implants as a new application of this material for craniofacial bone defect reconstruction. First, osteoblast (skeleton-related cell) cytotoxicity and genotoxicity were determined in vitro by comparing ZrO₂ implants and alumina particle air-abraded ZrO₂ implants to the following: 1. a titanium alloy (standard material); 2. ultrahigh-molecular-weight polyethylene (a modern material used in orbital surgery); 3. a negative control (minimally cytotoxic or genotoxic agent action); 4. a positive control (maximally cytotoxic or genotoxic agent action). Next, 14 custom in vivo clinical ZrO₂ implants were manufactured for post-traumatologic periorbital region reconstruction. The soft tissue position improvement in photogrammetry was recorded, and clinical follow-up was conducted at least 6 years postoperatively. All the investigated materials revealed no cytotoxicity. Alumina particle air-abraded ZrO2 implants showed genotoxicity compared to those without subjection to air abrasion ZrO₂, which were not genotoxic. The 6-month and 6- to 8-year clinical results were aesthetic and stable. Skeleton reconstructions using osseointegrated, radio-opaque, personalized implants comprising ZrO₂ material are the next option for craniofacial surgery.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Classical versus custom orbital wall reconstruction: Selected factors regarding surgery and hospitalization

PURPOSE

Nowadays, in orbital wall reconstruction, maxillofacial surgeons have the possibility to treat patients in modern ways such as with individual implants. Nevertheless, conventional treatment including standard titanium mesh shaped during the surgical procedure is also widely used. The aim of this study was to compare the above methods of orbital wall reconstructions.

MATERIALS AND METHODS

In the first group (39 cases), patients were treated by means of computer-aided design/computer-aided manufacturing (CAD/CAM) milled individual implants made of ultra-high-molecular-weight polyethylene, dioxide zirconium and rapid prototyping titanium mesh pre-bent on an ABS model made by a three-dimensional (3D) printer. In the second group (54 cases), intraoperative bending of titanium mesh was implemented.

RESULTS

Ophthalmologic outcomes were the same in both groups. In patients who had greater destruction of the orbit, surgical procedures were longer regardless of the material used for individual implants (p < 0.05). Time of surgery was shorter in patients in whom individual implants were used. Intraoperative bleeding was higher in patients who were treated using intraoperative bending titanium mesh (p < 0.01).

CONCLUSION

Application of CAD/CAM techniques do not give better ophthalmologic results in reference center but improve patient condition postoperatively. For this reason, CAD/CAM is a safer treatment method for patients.

Evolution of design considerations in complex craniofacial reconstruction using patient-specific implants

Previously published evidence has established major clinical benefits from using computer-aided design, computer-aided manufacturing, and additive manufacturing to produce patient-specific devices. These include cutting guides, drilling guides, positioning guides, and implants. However, custom devices produced using these methods are still not in routine use, particularly by the UK National Health Service. Oft-cited reasons for this slow uptake include the following: a higher up-front cost than conventionally fabricated devices, material-choice uncertainty, and a lack of long-term follow-up due to their relatively recent introduction. This article identifies a further gap in current knowledge – that of design rules, or key specification considerations for complex computer-aided design/computer-aided manufacturing/additive manufacturing devices. This research begins to address the gap by combining a detailed review of the literature with first-hand experience of interdisciplinary collaboration on five craniofacial patient case studies. In each patient case, bony lesions in the orbito-temporal region were segmented, excised, and reconstructed in the virtual environment. Three cases translated these digital plans into theatre via polymer surgical guides. Four cases utilised additive manufacturing to fabricate titanium implants. One implant was machined from polyether ether ketone. From the literature, articles with relevant abstracts were analysed to extract design considerations. In all, 19 frequently recurring design considerations were extracted from previous publications. Nine new design considerations were extracted from the case studies – on the basis of subjective clinical evaluation. These were synthesised to produce a design considerations framework to assist clinicians with prescribing and design engineers with modelling. Promising avenues for further research are proposed.

Orbital fracture repair outcomes with preformed titanium mesh implants and comparison to porous polyethylene coated titanium sheets

BACKGROUND

Restoration of orbital volume after internal orbital fractures can prevent enophthalmos. A variety of allografts are commonly used including titanium mesh with and without porous polyethylene coating. Some controversy exists over the use of uncoated titanium mesh in the orbit. Newer products contoured to the three dimensional orbital anatomy aim to improve reestablishment of the complex orbital shape though studies of outcomes with their use are limited.

METHODS

A retrospective chart review was performed to evaluate surgical outcomes in all patients who underwent orbital fracture repair with DePuy/Synthes titanium MatrixMIDFACE prefabricated implants (PFTi) as compared with porous polyethylene/titanium hybrid implants (PPETi) including Stryker Medpor Titan, MTB, and BTB implants. Incidence of reoperation, diplopia, and movement restriction between PFTi and PPETi groups and the risk ratio of the above outcomes between implant types were compared.

RESULTS

A total of 464 orbital implants were reviewed. Patients were divided by implant type with 195 patients receiving a PFTi implant and 269 patients receiving PPETi implant. (PFTi) and 269 had placement of a porous polyethylene/titanium hybrid implant. Despite statistically significant increased probability of utilization in more complex and delayed fractures, the PFTi implant showed no significant difference in complication profile or reoperation rate compared to the more commonly used PPETi.

CONCLUSIONS

PFTi implants, designed to replicate the native orbital shape, have similar surgical outcomes and no difference in complication profile compared to standard porous polyethylene/titanium implants hybrid plates.

3D-printing techniques in a medical setting: a systematic literature review

BACKGROUND

Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes.

METHODS

Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans.

RESULTS

227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure.

CONCLUSION

3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D-printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis.

Advantages and disadvantages of 3-dimensional printing in surgery: A systematic review

BACKGROUND

Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D printing applied in surgery.

METHODS

We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded.

RESULTS

A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing.

CONCLUSION

The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.

Repair of the Orbital Wall Fractures in Rabbit Animal Model Using Nanostructured Hydroxyapatite-Based Implant

Cellular uptake and cytotoxicity of nanostructured hydroxyapatite (nanoHAp) are dependent on its physical parameters. Therefore, an understanding of both surface chemistry and morphology of nanoHAp is needed in order to be able to anticipate its in vivo behavior. The aim of this paper is to characterize an engineered nanoHAp in terms of physico-chemical properties, biocompatibility, and its capability to reconstitute the orbital wall fractures in rabbits. NanoHAp was synthesized using a high pressure hydrothermal method and characterized by physico-chemical, structural, morphological, and optical techniques. X-ray diffraction revealed HAp crystallites of 21 nm, while Scanning Electron Microscopy (SEM) images showed spherical shapes of HAp powder. Mean particle size of HAp measured by DLS technique was 146.3 nm. Biocompatibility was estimated by the effect of HAp powder on the adhesion and proliferation of mesenchymal stem cells (MSC) in culture. The results showed that cell proliferation on powder-coated slides was between 73.4% and 98.3% of control cells (cells grown in normal culture conditions). Computed tomography analysis of the preformed nanoHAp implanted in orbital wall fractures, performed at one and two months postoperative, demonstrated the integration of the implants in the bones. In conclusion, our engineered nanoHAp is stable, biocompatible, and may be safely considered for reconstruction of orbital wall fractures.

Inaugural Survey on Practice Patterns of Orbital Floor Fractures for American Oral and Maxillofacial Surgeons

PURPOSE

In recent years, several studies have reported on practitioners' preferences for the treatment of orbital floor fractures, showing widely varying practice patterns. The purpose of the present study was to identify the practice patterns among oral and maxillofacial surgeons involved in the management of orbital floor fractures in the United States and compare them with the available published data.

MATERIALS AND METHODS

An anonymous survey was created and electronically mailed to surgeons. We also reviewed the published data on orbital floor fractures using a PubMed and MEDLINE search. The responses to the survey were analyzed using descriptive statistics.

RESULTS

The factors that had the greatest influence on the surgeon's decision to operate were a defect size > 2 cm2, enophthalmos, entrapment, and persistent diplopia. The most common surgical approach reported was a preseptal transconjunctival approach (32.0%), followed by the subciliary (27.9%) and postseptal transconjunctival (26.2%) approaches. The most commonly reported implant for orbital reconstruction was titanium (65.4%), followed by Medpor (43.7%) and composite Medpor and titanium (26.4%). The review of the published data showed a consensus among many of the operative indications mentioned, including a large defect size, enophthalmos, clinical entrapment, and persistent diplopia.

CONCLUSIONS

Oral and maxillofacial surgeons in the United States have a wide range of practice habits in the management of orbital floor fractures. Although the quality of the available evidence is poor, it supports a consistent approach to the management of orbital floor fractures in terms of the indications and surgical approach. The choice of reconstructive material and timing of repair remain more controversial. A clear need exists for improvement in the available data to help guide and set standards of care for the specialties managing orbital floor fractures.

Orbital Wall Reconstruction with Two-Piece Puzzle 3D Printed Implants: Technical Note

The purpose of this article is to describe a technique for secondary reconstruction of traumatic orbital wall defects using titanium implants that act as three-dimensional (3D) puzzle pieces. We present three cases of large defect reconstruction using implants produced by Xilloc Medical B.V. (Maastricht, the Netherlands) with a 3D printer manufactured by LayerWise (3D Systems; Heverlee, Belgium), and designed using the biomedical engineering software programs ProPlan and 3-Matic (Materialise, Heverlee, Belgium). The smaller size of the implants allowed sequential implantation for the reconstruction of extensive two-wall defects via a limited transconjunctival incision. The precise fit of the implants with regard to the surrounding ledges and each other was confirmed by intraoperative 3D imaging (Mobile C-arm Systems B.V. Pulsera, Philips Medical Systems, Eindhoven, the Netherlands). The patients showed near-complete restoration of orbital volume and ocular motility. However, challenges remain, including traumatic fat atrophy and fibrosis.

Reconstruction of orbital floor blow-out fractures with autogenous iliac crest bone: a retrospective study including maxillofacial and ophthalmology perspectives

This is a 10-year retrospective study of patients with an isolated unilateral orbital floor fracture reconstructed with an autogenous iliac crest bone graft. The following inclusion criteria applied: isolated orbital floor fracture without involvement of the orbital rim or other craniofacial injuries, pre-/post-operative ophthalmological/orthoptic follow-up, pre-operative CT. Variables recorded were patient age and gender, aetiology of injury, time to surgery, follow-up period, surgical morbidity, diplopia pre- and post-operatively (Hess test), eyelid position, visual acuity, and the presence of en-/or exophthalmos (Hertel exophthalmometer). Twenty patients met the inclusion criteria. The mean age was 29 years. The mean follow up period was 26 months. No patient experienced significant donor site morbidity. There were no episodes of post-operative infection or graft extrusion. Three patients had diplopia in extremes of vision post-operatively, but no interference with activities of daily living. One patient had post-operative enophthalmos. Isolated orbital blow-out fractures may be safely and predictably reconstructed using autogenous iliac crest bone. The rate of complications in the group of patients studied was low. The value of pre- and post-operative ophthalmology consultation cannot be underestimated, and should be considered the standard of care in all patients with orbitozygomatic fractures, in particular those with blow-out fractures.

A case series of rapid prototyping and intraoperative imaging in orbital reconstruction

In Christchurch Hospital, rapid prototyping (RP) and intraoperative imaging are the standard of care in orbital trauma and has been used since February 2013. RP allows the fabrication of an anatomical model to visualize complex anatomical structures which is dimensionally accurate and cost effective. This assists diagnosis, planning, and preoperative implant adaptation for orbital reconstruction. Intraoperative imaging involves a computed tomography scan during surgery to evaluate surgical implants and restored anatomy and allows the clinician to correct errors in implant positioning that may occur during the same procedure. This article aims to demonstrate the potential clinical and cost saving benefits when both these technologies are used in orbital reconstruction which minimize the need for revision surgery.

Infraorbital nerve block for isolated orbital floor fractures repair: review of 135 consecutive cases

BACKGROUND

Orbital blowout fractures can be managed by several surgical specialties including plastic and maxillofacial surgery, otolaryngology, and ophthalmology. Recommendations for surgical fracture repair depend on a combination of clinical and imaging studies to evaluate muscle/nerve entrapment and periorbital tissue herniation.

METHODS

The aim of this study was to verify the applicability of regional anesthesia when repairing orbital floor fractures. A retrospective chart review was performed for isolated orbital floor fractures treated at the Department of Maxillofacial Surgery in Florence between May 2011 and July 2012. The study included 135 patients who met the inclusion criteria: 96 subjects were male (71%) and 39 were female (29%). The mean age was 45.3 years, ranging from 16 to 77 years.

RESULTS

The results revealed that isolated anterior orbital floor fractures can be safely repaired under regional and local anesthesia. Regional and local anesthesia should be combined with intravenous sedation when the fracture involves the posterior floor. The surgical outcome was comparable to the outcome achieved under general anesthesia. There was a lower rate of surgical revisions due to concealed malposition or entrapment of the inferior rectus muscle (19% vs 22%). However, this result was not statistically significant (P > 0.05).

CONCLUSIONS

THERE ARE SEVERAL ADVANTAGES TO SURGICALLY REPAIRING ISOLATED ORBITAL FLOOR FRACTURES UNDER REGIONAL AND LOCAL ANESTHESIA THAT INCLUDE THE FOLLOWING: surgeons can check the surgical outcome (enophthalmos and extrinsic ocular muscles function) intraoperatively, thereby reducing the reoperation rate; patient discomfort due to general anesthesia is eliminated; and the hospital stay is reduced, thus decreasing overall healthcare costs.

3D modeling, custom implants and its future perspectives in craniofacial surgery

Custom implants for the reconstruction of craniofacial defects have gained importance due to better performance over their generic counterparts. This is due to the precise adaptation to the region of implantation, reduced surgical times and better cosmesis. Application of 3D modeling in craniofacial surgery is changing the way surgeons are planning surgeries and graphic designers are designing custom implants. Advances in manufacturing processes and ushering of additive manufacturing for direct production of implants has eliminated the constraints of shape, size and internal structure and mechanical properties making it possible for the fabrication of implants that conform to the physical and mechanical requirements of the region of implantation. This article will review recent trends in 3D modeling and custom implants in craniofacial reconstruction.

Comparison of pre-bent titanium mesh versus polyethylene implants in patient specific orbital reconstructions

Introduction

Computerized tomography DICOM file can be relatively easily transformed to a virtual 3D model. With the help of additional software we are able to create the mirrored model of an undamaged orbit and on this basis produce an individual implant for the patient Authors decided to apply implants with any thickness, which are authors own invention to obtain volumetric support and more stable orbital wall reconstruction outcome. Material of choice was ultra-high molecular weight polyethylene (UHMWPE).

Objective

The aim of this study was to present and compare functional results of individual reconstructions of orbital wall using either titanium mesh or ultra-high molecular weight polyethylene.

Materials and methods

57 consecutive patients affected by orbital wall fracture (46 males, 11 females, mean age 34±14 year) were treated in Department of Maxillofacial Surgery from 2010 to 2012. In the first group we used patient specific treatment by titanium mesh shaped on a 3D printed model of a mirrored intact orbit (37 orbits) or by individually manufactured UHMW-PE implantby CAM milling in second group (20 orbits). All of these patients were subjected to preoperative helical computerized tomography and consultation of an ophthalmologist (including binocular single vision loss test - BSVL). Further on, patients were operated under general anaesthesia using transconjuctival approach. BSVL was again evaluated post-operationally in 1 month and 6 months later.

Results

Functional treatment results (BSVL) for both groups were similar in 1 month as well as 6 months post operational time. There was no statistically significant difference between these two groups.

Conclusions

This study of 6 months functional result assessment of pre-bent individual implants and CNC milled ultra-high molecular weight polyethylene of the orbital wall has shown it to be a predictable reconstruction method. Individually shaped UHMWPE seems to be as good as pre-bent titanium mesh.

Computer-aided orbital wall defects treatment by individual design ultrahigh molecular weight polyethylene implants

Despite of well-known advantages of high molecular weight polyethylene (Medpor, Synpore) in orbital reconstructions, the thickness of those implants significantly exceeds 0.5 mm and precise modification of thickness is limited. The aim of this study was to present the application of a self-developed method of treatment orbital wall fracture by custom implant made of ultrahigh molecular weight polyethylene (UHMW-PE).

MATERIAL AND METHOD

First, the test of influence of sterilization process upon implant deformation was performed (autoclaving, ethylene oxide, gas plasma, irradiation). Next, ten cases for delayed surgical treatment of orbital fracture were included into this study (7 males, 3 females). Based on CT scan and mirrored technique, a CAD model of virtual implant for repairing orbital wall was made. Then, an implant was manufactured with a computer numerical controlled milling machine from UHMW-PE block, sterilized and used during a surgical procedure. Clinically used implants had thickness from 0.2 to 4.0 mm.

RESULTS

The best method of sterilization is ethylene oxide process, and the worst is autoclaving. In this series of delayed surgical cases, functional results of orbital surgery are worse than in simpler, early treated cases, but long-term subsidence of diplopia is noticeable [10% poor results]. The results of the treatment depend on the initial level of diplopia where severe initial diplopia to be corrected requires thicker implants (p < 0.01). It also leads to longer surgical procedures (p < 0.01), but prolongation of the surgery had no negative influence upon results of any investigated follow-up examinations. Obviously, the orbital destruction intensity is related to injury-evoked initial diplopia but it also influences whole results of treatment up to 12 months post-op. Interesting result is presented by the relation of maximal implant thickness to 12-month diplopia evaluation. Thicker implants used result in lower residual diplopia (p < 0.05). This is important because of the correlation between the higher orbital destruction intensity with a thicker UHMW-PE implant (p < 0.05) applied in this series.

CONCLUSION

Patient-specific ultrahigh molecular weight polyethylene implants enable precise reconstructions of orbital wall. One should not be afraid of a significant eye globe reposition caused by these thickness modulated implants, as such repositioning is essential for an efficient correction of enophthalmos.

Biomaterials for repair of orbital floor blowout fractures: a systematic review

PURPOSE

To evaluate the reported use and outcomes of implant materials used for the restoration of post-traumatic orbital floor defects in adults.

MATERIALS AND METHODS

A systematic search of the English literature was performed in the databases of PubMed, Cochrane Library, and EMBASE. The study selection process was adapted from the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement, and 55 articles complied with the study inclusion criteria. The primary outcome measures were diplopia, enophthalmos, graft extrusion/displacement, and infection related to the graft material. The secondary outcome measures were infraorbital paresthesia, orbital dystopia, orbital soft tissue entrapment, and donor-site complications.

RESULTS

Of 55 articles, 41 (74.5%) evaluated were retrospective case series, 9 (16.4%) were retrospective case-control studies, 3 (5.5%) were controlled trials, and 2 (3.6%) were prospective case series. Autogenous graft materials were predominantly used in 19 studies, alloplastic materials were used in 33 studies, and the remaining 3 articles reported on allogeneic materials. Overall, 19 different types of implant materials were used in 2,483 patients. Of 827 patients with diplopia before surgery, 151 (18.3%) had diplopia postoperatively. Of 449 patients with enophthalmos before surgery, 134 (29.8%) had enophthalmos postoperatively. Only 2 patients (0.1%) and 14 patients (0.6%) had graft extrusion/displacement and infection related to the graft material, respectively; alloplastic biomaterials were used in all of these cases.

CONCLUSIONS

All graft materials used were successful to variable degrees because all studies reported improvement in terms of the recorded outcome measures. A guideline for choice of implant material based on defect size was developed.

Accuracy of medical models made by additive manufacturing (rapid manufacturing)

BACKGROUND

Additive manufacturing (AM) is being increasingly used for producing medical models. The accuracy of these models varies between different materials, AM technologies and machine runs.

PURPOSE

To determine the accuracy of selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet technologies in the production of medical models.

MATERIAL

3D skull models: "original", "moderate" and "worse". SLS, 3DP and PolyJet models, and a coordinate measuring machine (CMM).

METHODS

Measuring balls designed for measurements were attached to each 3D model. Skull models were manufactured using SLS, 3DP and PolyJet. The midpoints of the balls were determined using CMM. The distances between these points were calculated and compared with the 3D model.

RESULTS

The dimensional error for the PolyJet was 0.18 ± 0.12% (first measurement) and 0.18 ± 0.13% (second measurement), for SLS 0.79 ± 0.26% (first model) and 0.80 ± 0.32% (second model), and for 3DP 0.67 ± 0.43% (original model, first measurement) and 0.69 ± 0.44% (original model, second measurement), 0.38 ± 0.22% (moderate model) and 0.55 ± 0.37% (worse model). Repeatability of the measurement method was 0.12% for the PolyJet and 0.08% for the 3DP.

CONCLUSION

A novel measuring technique was developed and its repeatability was found to be good. The accuracy of the PolyJet was higher when compared with SLS or 3DP.

The use of modern imaging techniques in the diagnosis and treatment planning of patients with orbital floor fractures

BACKGROUND

Ocular motility impairment associated with orbital trauma may have several causes and manifest with various clinical symptoms. In some cases orbital reconstructive surgery can be very challenging and the results are often unsatisfactory. The use of modern imaging techniques aids proper diagnosis and surgical planning.

CASE REPORT

The authors present the case of a 29-year-old male who sustained trauma to the left orbit. Orthoptic examination revealed limited supra- and infraduction of the left eye. The patient reported diplopia in upgaze and downgaze with primary position spared. Dynamic magnetic resonance imaging (dMRI) was performed, which revealed restriction of the left inferior rectus muscle in its central section. A patient-specific anatomical model was prepared on the basis of 3-dimensional computed tomography (CT) study of the intact orbit, which was used to prepare a custom pre-bent titanium mesh implant. The patient underwent reconstructive surgery of the orbital floor.

CONCLUSIONS

Modern imaging techniques such as dMRI and 3-dimensional CT reconstruction allow us to better understand the pathophysiology of orbital floor fractures and to precisely plan surgical treatment.