Individual preformed titanium meshes for orbital fractures

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.

Titanium Implants Coated with Hydroxyapatite Used in Orbital Wall Reconstruction-A Literature Review

With the increasing incidences of orbital wall injuries, effective reconstruction materials and techniques are imperative for optimal clinical outcomes. In this literature review, we delve into the efficacy and potential advantages of using titanium implants coated with nanostructured hydroxyapatite for the reconstruction of the orbital wall. Titanium implants, recognized for their durability and mechanical strength, when combined with the osteoconductive properties of hydroxyapatite, present a potentially synergistic solution. The purpose of this review was to critically analyze the recent literature and present the state of the art in orbital wall reconstruction using titanium implants coated with nanostructured hydroxyapatite. This review offers clinicians detailed insight into the benefits and potential drawbacks of using titanium implants coated with nanostructured hydroxyapatite for orbital wall reconstruction. The highlighted results advocate for its benefits in terms of osseointegration and provide a novel strategy for orbital reconstruction, though further studies are essential to establish long-term efficacy and address concerns.

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.

Usage of Object Matching Algorithms Combined with Mixed Reality for Enhanced Decision Making in Orbital Reconstruction-A Technical Note

This technical note describes the usage of object matching to virtually compare different modes of reconstruction in orbital trauma and display the results to the surgeon and the patient pre-operatively via mixed reality devices for enhanced surgical decision making and immersive patient education. A case of an orbital floor fracture is presented for which surface and volume matching were implemented to compare orbital reconstruction utilizing pre-fabricated titanium meshes versus patient-specific implants. The results could be visualized by mixed reality devices to further enhance surgical decision-making. The data sets were demonstrated to the patient in mixed reality for immersive patient education and enhanced shared decision making. The advantages of the new technologies are discussed in view of the new possibilities of improved patient education and informed consent processes, as well as new ways of teaching medical trainees.

Comparison of Anatomical Preformed Titanium Implants and Patient-Specific CAD/CAM Implants in the Primary Reconstruction of Isolated Orbital Fractures-A Retrospective Study

BACKGROUND/AIM

Reconstruction of the fractured orbit remains a challenge. The aim of this study was to compare anatomical preformed titanium orbital implants with patient-specific CAD/CAM implants for precision and intraoperative applicability.

MATERIAL AND METHODS

A total of 75 orbital reconstructions from 2012 to 2022 were retrospectively assessed for their precision of implant position and intra- and postoperative revision rates. For this purpose, the implant position after digital orbital reconstruction was checked for deviations by mirroring the healthy orbit at 5 defined points, and the medical records of the patients were checked for revisions.

RESULTS

The evaluation of the 45 anatomical preformed orbital implant cases showed significantly higher deviations and an implant inaccuracy of 66.6% than the 30 CAD/CAM cases with only 10% inaccuracy. In particular, the CAD/CAM implants were significantly more precise in medial and posterior positioning. In addition, the intraoperative revision rates of 26.6% vs. 11% after 3D intraoperative imaging and the postoperative revision rates of 13% vs. 0 for the anatomical preformed implants were significantly higher than for patient-specific implants.

CONCLUSION

We conclude that patient-specific CAD/CAM orbital implants are highly suitable for primary orbital reconstruction. These seem to be preferable to anatomical preformed implants in terms of precision and revision rates.

Outcome of Precontoured Titanium Mesh in the Reconstruction of Orbital Blowout Fractures

Background Orbital blowout fractures are peculiar injuries causing disruption of both ocular function and symmetry. We present our experience with the use of a precontoured titanium mesh in orbital blowout fractures.

Methods A retrospective study of patients undergoing correction of orbital blowout fractures with a precontoured titanium mesh was done at a tertiary care center in Mumbai. Data regarding demographics and pre- and postoperative clinical and radiological attributes were retrieved and compared.

Results A total of 21 patients (19 males and 2 females) underwent correction of blowout fractures with a precontoured titanium mesh. The follow-up period ranged from 6 to 10 months. Road traffic accident (76%) was the most common etiology. Twenty (95%) patients had impure blowout fractures and 1 (5%) patient had a pure blowout. The orbital floor was most commonly fractured (16 [76%]). Associated fractures of the zygomaticomaxillary complex were found in 71% of patients. All patients were operated on within 3 weeks of trauma. A comparison of the operated and uninjured sides on coronal views of computed tomography (CT) scan in nine patients by Photopea application revealed a correction of the increased cross-sectional area in all cases. Enophthalmos was completely corrected in 94% patients, while 92% patients had complete correction of diplopia. One patient with a comminuted zygomatic fracture had persistent diplopia and mild enophthalmos. Infraorbital paresthesia persisted in 58% patients at 6 months of follow-up. No significant postoperative complications were noted.

Conclusion The precontoured titanium mesh restores orbital wall anatomy and is safe, quick, fairly easy, and reproducible with a shorter learning curve. With proper patient selection and execution, prefabricated titanium mesh can serve as an excellent reconstructive option in blowout fractures of the orbit.

Patient-Specific Orbital Implants Vs. Pre-Formed Implants for Internal Orbital Reconstruction

PURPOSE

To compare the outcome of orbital blowout fracture repair by means of pre-formed porous-polyethylene titanium implants (PFI) vs patient-specific porous-polyethylene implants (PSI).

METHODS

Retrospective cohort study. Baseline characteristics, ophthalmic examination results, ocular motility, fracture type, the timing of surgery, implant type, and final relative enophthalmos of all patients operated on for blow-out fractures in a single center were collected and analyzed.

RESULTS

Twenty-seven patients (mean age 39 years, 9 females) were enrolled. Sixteen underwent fracture repair with PFI and 11 with PSI at 11 months (median) post-trauma. Mean follow-up duration was 1.1 years. Both groups showed significant postoperative improvement in primary or vertical gaze diplopia (P = .03, χ²). Relative enophthalmos improved from -3.2 preoperative PFI to -1.7 mm postoperative PFI, and from -3.0 mm preoperative PSI to -1.1 mm postoperative PSI (P= .1). PSI patients had non-significantly less postoperative enophthalmos and globe asymmetry than PFI patients. The outcome was not influenced by previous surgery, age, sex, number of orbital walls involved in the initial trauma, or medial wall involvement (linear regression). Both groups sustained complications unrelated to implant choice.

CONCLUSION

Both PSI and PFI yielded good outcomes in this study. PSI may be a good alternative to PFI in primary or secondary orbital blowout fracture repair with less enophthalmos and globe asymmetry, in spite of the possible disadvantages of production time, a relatively larger design, and challenging insertion. Since it is a mirror image of the uninjured orbit, it may be beneficial in extensive fractures.

Management of Infraorbital Rim Fracture Through Intraoral Approach

Purpose

The aim of our study was to evaluate the feasibility of an intraoral approach in the management of infraorbital rim fracture.

Patients and Methods

A total of 12 patients of which four were female and five were male with isolated unilateral zygomaticomaxillary complex (ZMC) fractures, essentially involving the infraorbital foramen (right or left), were included in this study. Indications for surgical intervention were cosmetic deformity, disturbance of vision, persistent paresthesia, or impaired mandibular movement. All the patients were subjected to thorough preoperative evaluation. A three-point fixation was performed in all the patients. Various parameters such as time required for exposure and the amount of accessibility were assessed intraoperatively, while the stability of the fixation and paresthesia pertaining to the distribution of the infraorbital nerve were assessed postoperatively.

Results

A total of 12 patients with a mean age of 35.75 ± 12.7 years were included in the study. The mean time recorded for exposure and fixation was 21.33 ± 2.8 min. The accessibility was rated as "excellent" in 92% (11 patients) of the operated cases and rated "satisfactory" in 8% (1 patient) of the operated cases. The fixation was found to be stable in 100% of the cases. By the end of 8 months, normal mechanoreceptor response was elicited in 42% (five patients) of the cases and normal nocireceptor response was elicited in 92% (11 patients) of the cases.

Conclusion

The intraoral approach for fixation of the infraorbital rim is versatile and can be mastered even by novice surgeons. The virtual lack of complications and short learning curve make this approach an invincible modus operandi in a surgeon's repertoire.

Analyzing the Fitting of Novel Preformed Osteosynthesis Plates for the Reduction and Fixation of Mandibular Fractures

Purpose: The known preformed osteosynthesis plates for the midface are helpful tools for a precise and fast fixation of repositioned fractures. The purpose of the current study is to analyze the precision of newly developed prototypes of preformed osteosynthesis plates for the mandible. Methods: Four newly designed preformed osteosynthesis plates, generated by a statistical shape model based on 115 CT scans, were virtually analyzed. The used plates were designed for symphyseal, parasymphyseal, angle, and condyle fractures. Each type of plate has three different sizes. For analysis, the shortest distance between the plate and the bone surface was measured, and the sum of the plate-to-bone distances over the whole surface was calculated. Results: A distance between plate and bone of less than 1.5 mm was defined as sufficient fitting. The plate for symphyseal fractures showed good fitting in 90% of the cases for size M, and in 84% for size L. For parasymphyseal fractures, size S fits in 80%, size M in 68%, and size L in 65% of the cases. Angle fractures with their specific plate show good fitting for size S in 53%, size M in 60%, and size L in 47%. The preformed plate for the condyle part fits for size S in 75%, for size M in 85%, and for size L in 74% of the cases. Conclusion: The newly developed mandible plates show sufficient clinical fitting to ensure adequate fracture reduction and fixation.

A deep learning method for automatic segmentation of the bony orbit in MRI and CT images

This paper proposes a fully automatic method to segment the inner boundary of the bony orbit in two different image modalities: magnetic resonance imaging (MRI) and computed tomography (CT). The method, based on a deep learning architecture, uses two fully convolutional neural networks in series followed by a graph-search method to generate a boundary for the orbit. When compared to human performance for segmentation of both CT and MRI data, the proposed method achieves high Dice coefficients on both orbit and background, with scores of 0.813 and 0.975 in CT images and 0.930 and 0.995 in MRI images, showing a high degree of agreement with a manual segmentation by a human expert. Given the volumetric characteristics of these imaging modalities and the complexity and time-consuming nature of the segmentation of the orbital region in the human skull, it is often impractical to manually segment these images. Thus, the proposed method provides a valid clinical and research tool that performs similarly to the human observer.

Surgical instrument to improve implant positioning in orbital reconstruction: a feasibility study

Adequate positioning of an orbital implant during orbital reconstruction surgery is essential for restoration of the pre-traumatised anatomy, but visual appraisal of its position is limited by the keyhole access and protruding soft tissues. A positioning instrument that attaches to the implant was designed to provide feedback outside the orbit. The goal of this study was to evaluate the accuracy of placement with the instrument and compare it with the accuracy of placement by visual appraisal. Ten orbits in five human cadaver heads were reconstructed twice: once using visual appraisal and once using the instrument workflow. No significant improvement was found for the roll (5.8° vs 3.4°, respectively, p=0.16), pitch (2.1° vs 1.5°, p=0.56), or translation (2.9 mm vs 3.3 mm, p=0.77), but the yaw was significantly reduced if the instrument workflow was used (15.3° vs 2.9°, p=0.02). The workflow is associated with low costs and low logistical demands, and may prevent outliers in implant positioning in a clinical setting when intraoperative navigation or patient-specific implants are not available.

Customized Orbit and Frontal Bone Implants

Orbitocranial reconstruction objectives include creation of a solid barrier between intracranial contents and the environment allowing restoration of physiologic homeostasis and restoration of aesthetic craniofacial contours. Historically, bone grafts have been used for reconstruction but were fraught with unpredictable resorption and imperfect contouring given the complex anatomy of the orbitofrontal bones. With advances in three-dimensional modeling technology, alloplastic custom implants in orbital and frontal bone reconstruction have allowed for rapid fixation reducing surgical times and improved cosmesis.

Intraoperative Image-Guided Navigation in Craniofacial Surgery: Review and Grading of the Current Literature

INTRODUCTION

Image-guided navigation has existed for nearly 3 decades, but its adoption to craniofacial surgery has been slow. A systematic review of the literature was performed to assess the current status of navigation in craniofacial surgery.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) systematic review of the Medline and Web of Science databases was performed using a series of search terms related to Image-Guided Navigation and Craniofacial Surgery. Titles were then filtered for relevance and abstracts were reviewed for content. Single case reports were excluded as were animal, cadaver, and virtual data. Studies were categorized based on the type of study performed and graded using the Jadad scale and the Newcastle-Ottawa scales, when appropriate.

RESULTS

A total of 2030 titles were returned by our search criteria. Of these, 518 abstracts were reviewed, 208 full papers were evaluated, and 104 manuscripts were ultimately included in the study. A single randomized controlled trial was identified (Jadad score 3), and 12 studies were identified as being case control or case cohort studies (Average Newcastle-Ottawa score 6.8) The most common application of intraoperative surgical navigation cited was orbital surgery (n = 36), followed by maxillary surgery (n = 19). Higher quality studies more commonly pertained to the orbit (6/13), and consistently show improved results.

CONCLUSION

Image guided surgical navigation improves outcomes in orbital reconstruction. Although image guided navigation has promise in many aspects of craniofacial surgery, current literature is lacking and future studies addressing this paucity of data are needed before universal adoption can be recommended.

Magnetic resonance imaging for three-dimensional printing of the bony orbit: is clinical use imminent?

The aim of this study was to examine the accuracy of three dimensionally (3D) printed models of the bony orbit derived from magnetic resonance imaging (MRI) for the purpose of preoperative plate bending in the setting of orbital blowout fracture. Retrospective computed tomography (CT) and MRI data from patients with suspected orbital fractures were used. Virtual models were manually generated and analysed for spatial accuracy of the fracture margins. 3D-printed models were produced and orbital fan plates bent by a single operator. The plates were then digitized and analysed for spatial discrepancy using reverse engineering software. Seven orbital blowout fractures were evident in six orbits. Analysis of the virtual models revealed high congruence between blowout fracture margins on CT and MRI (n=7, average deviation 0.85mm). Three zygomaticomaxillary complex fractures were seen, for which MRI did not demonstrate the same accuracy. For plates bent to the 3D-printed models of blowout fractures (n=6), no significant difference was found between those bent to CT versus those bent to MRI when compared for average surface and average border deviation (Wilcoxon signed rank test). Orbital blowout fractures can be defined on MRI with clinically acceptable accuracy. 3D printing of orbital biomodels from MRI for bending reconstructive plates is an acceptable and accurate technique.

Generation of customized orbital implant templates using 3-dimensional printing for orbital wall reconstruction

OBJECTIVES

To describe and evaluate a novel surgical approach to orbital wall reconstruction that uses three-dimensionally (3D) printed templates to mold a customized orbital implant.

METHODS

A review was conducted of 11 consecutive patients who underwent orbital wall reconstruction using 3D-printed customized orbital implant templates. In these procedures, the orbital implant was 3D pressed during surgery and inserted into the fracture site. The outcomes of this approach were analyzed quantitatively by measuring the orbital tissue volumes within the bony orbit using computed tomography.

RESULTS

All 11 orbital wall reconstructions (6 orbital floor and 5 medial wall fractures) were successful with no post operative ophthalmic complications. Statistically significant differences were found between the preoperative and post operative orbital tissue volumes for the affected orbit (24.00 ± 1.74 vs 22.31 ± 1.90 cm³; P = 0.003). There was no statistically significant difference found between the tissue volume of the contralateral unaffected orbit and the affected orbit after reconstruction (22.01 ± 1.60 cm³ vs 22.31 ± 1.90 cm³; P = 0.182).

CONCLUSION

3D-printed customized orbital implant templates can be used to press and trim conventional implantable materials with patient-specific contours and sizes for optimal orbital wall reconstruction. It is difficult to design an orbital implant that exactly matches the shape and surface of a blowout fracture site due to the unique 3D structure of the orbit. The traditional surgical method is to visually inspect the fracture site and use eye measurements to cut a two-dimensional orbital implant that corresponds to the anatomical structure of the fracture site. However, implants that do not fit the anatomical structure of a fracture site well can cause complications such as enophthalmos, diplopia and displacement of the implant.

New and emerging patient-centered CT imaging and image-guided treatment paradigms for maxillofacial trauma

This article reviews the conceptual framework, available evidence, and practical considerations pertaining to nascent and emerging advances in patient-centered CT-imaging and CT-guided surgery for maxillofacial trauma. These include cinematic rendering-a novel method for advanced 3D visualization, incorporation of quantitative CT imaging into the assessment of orbital fractures, low-dose CT imaging protocols made possible with contemporary scanners and reconstruction techniques, the rapidly growing use of cone-beam CT, virtual fracture reduction with design software for surgical pre-planning, the use of 3D printing for fabricating models and implants, and new avenues in CT-guided computer-aided surgery.

Low-Cost 3D Printing Orbital Implant Templates in Secondary Orbital Reconstructions

PURPOSE

Despite its increasing use in craniofacial reconstructions, three-dimensional (3D) printing of customized orbital implants has not been widely adopted. Limitations include the cost of 3D printers able to print in a biocompatible material suitable for implantation in the orbit and the breadth of available implant materials. The authors report the technique of low-cost 3D printing of orbital implant templates used in complex, often secondary, orbital reconstructions.

METHODS

A retrospective case series of 5 orbital reconstructions utilizing a technique of 3D printed orbital implant templates is presented. Each patient's Digital Imaging and Communications in Medicine data were uploaded and processed to create 3D renderings upon which a customized implant was designed and sent electronically to printers open for student use at our affiliated institutions. The mock implants were sterilized and used intraoperatively as a stencil and mold. The final implant material was chosen by the surgeons based on the requirements of the case.

RESULTS

Five orbital reconstructions were performed with this technique: 3 tumor reconstructions and 2 orbital fractures. Four of the 5 cases were secondary reconstructions. Molded Medpor Titan (Stryker, Kalamazoo, MI) implants were used in 4 cases and titanium mesh in 1 case. The stenciled and molded implants were adjusted no more than 2 times before anchored in place (mean 1). No case underwent further revision.

CONCLUSIONS

The technique and cases presented demonstrate 1) the feasibility and accessibility of low-cost, independent use of 3D printing technology to fashion patient-specific implants in orbital reconstructions, 2) the ability to apply this technology to the surgeon's preference of any routinely implantable material, and 3) the utility of this technique in complex, secondary reconstructions.

Three dimensional reconstruction of late post traumatic orbital wall defects by customized implants using CAD-CAM, 3D stereolithographic models: A case report

Aim

Purpose of this case report is to highlight the precision and accuracy obtained with patient specific implants for orbital reconstruction designed on the basis of volumetric analysis of orbital computed tomographic scan (CT) scans using virtual planning, computerised designing and manufacturing and stereolithographic models to correct late post-traumatic orbital deformities such as enophthalmos and diplopia.

Material and methods

This case report describes a patient who visited our outpatient clinic for correction of enophthalmos and persistent diplopia in upward gaze, seven months post trauma. Three dimensional (3D) virtual treatment planning was carried out by using the 3D CT data. The unaffected orbit of the contralateral side was superimposed on the deformed orbit to highlight the defect and a customized implant was designed in the desired size and shape on the virtual model using computer aided designing and manufacturing (CAD-CAM) and milled in titanium mesh for precise anatomic orbital reconstruction.

Results

There was a marked improvement in both the diplopia in upward gaze and enophthalmos post surgery when the customized patient specific orbital implant was used.

Conclusion

The concept of using customized implant with the help of 3D virtual treatment planning, 3D stereolithographic models and CAD-CAM greatly improves the correction of extremely difficult late post-traumatic orbital deformities.

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.

Quantitative Assessment of Orbital Implant Position--A Proof of Concept

Introduction

In orbital reconstruction, the optimal location of a predefined implant can be planned preoperatively. Surgical results can be assessed intraoperatively or postoperatively. A novel method for quantifying orbital implant position is introduced. The method measures predictability of implant placement: transformation parameters between planned and resulting implant position are quantified.

Methods

The method was tested on 3 human specimen heads. Computed Tomography scans were acquired at baseline with intact orbits (t0), after creation of the defect (t1) and postoperatively after reconstruction of the defect using a preformed implant (t2). Prior to reconstruction, the optimal implant position was planned on the t0 and t1 scans. Postoperatively, the planned and realized implant position were compared. The t0 and t2 scans were fused using iPlan software and the resulting implant was segmented in the fused t2 scan. An implant reference frame was created (Orbital Implant Positioning Frame); the planned implant was transformed to the reference position using an Iterative Closest Point approach. The segmentation of the resulting implant was also registered on the reference position, yielding rotational (pitch, yaw, roll) as well as translational parameters of implant position.

Results

Measurement with the Orbital Implant Positioning Frame proved feasible on all three specimen. The positional outcome provided more thorough and accurate insight in resulting implant position than could be gathered from distance measurements alone. Observer-related errors were abolished from the process, since the method is largely automatic.

Conclusion

A novel method of quantifying surgical outcome in orbital reconstructive surgery was presented. The presented Orbital Implant Positioning Frame assessed all parameters involved in implant displacement. The method proved to be viable on three human specimen heads. Clinically, the method could provide direct feedback intraoperatively and could improve postoperative evaluation of orbital reconstructive surgery.

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 the orbital floor with polydioxanone: a long-term clinical survey of up to 12 years

Fractures of the orbital floor are common in injured patients, who often require operation to prevent complications and, among other materials, polydioxanone is widely used. The aim of this study was to evaluate the long-term outcomes of fractures of the orbital floor that had been reconstructed with polydioxanone foil. A total of 101 patients (73 men and 28 women) who had reconstruction of the orbital floor for defects of 2cm(2) or smaller with polydioxanone implants, over a mean (SD) time period of 8 (2) years were evaluated. Sensitivity of the infraorbital nerve, ocular motility, and diplopia were evaluated and correlated with perioperative values. Persistent hyperaesthesia was found in 15 patients, whereas in another 15 the hyperaesthesia recovered completely over time. Three patients had double vision during follow-up. Twenty patients with preoperative diplopia had no persistent double vision postoperatively, and 15 patients with disturbed ocular motility recovered completely. Two patients had persistently disturbed motility, and one patient had enophthalmos. There was a significant association between hyperaesthesia preoperatively and postoperatively (p= 0.005). In most patients reconstruction of the orbital floor with polydioxanone was successful. Long-term complications such as diplopia, compromised bulbar motility, and hyperaesthesia of the cheek were seen in a few cases, but might not have been solely related to the use of polydioxanone.

The management of naso-orbital-ethmoid (NOE) fractures

The bony naso-orbital-ethmoid (NOE) complex is a 3-dimensional delicate anatomic structure. Damages to this region may result in severe facial dysfunction and malformation. The management and optimal surgical treatment strategies of NOE fractures remain controversial. For a patient with NOE trauma, doctors should perform comprehensive clinical examination and radiographic analysis to assess the type and extent of fracture. The results of assessment will assist doctors to make a patientspecific program for the sake of reducing post-operation complications and restoring normal appearance and function as much as possible. This review focuses on the advancement of management of NOE fractures including symptoms, classifications, diagnosis, approaches, treatment and new techniques in this field.

Assessing the bilateral geometrical differences of the tibia--are they the same?

Contralateral bones are often used in many medical applications but it is assumed that their bilateral differences are insignificant. Previous studies used a limited number of distance measurements in quantifying the corresponding differences; therefore, little is known about their bilateral 3D surface asymmetries. The aim of the study is to develop a comprehensive method to quantify geometrical asymmetries between the left and right tibia in order to provide first results on whether the contralateral tibia can be used as an equivalent reference. In this study, 3D bone models were reconstructed from CT scans of seven tibiae pairs, and 34 variables consisting of 2D and 3D measurements were measured from various anatomical regions. All 2D measurements, and lateral plateau and distal subchondral bone surface measurements showed insignificant differences (p>0.05), but the rest of the surfaces showed significant differences (p<0.05). Our results suggest that the contralateral tibia can be used as a reference especially in surgical applications such as articular reconstructions since the bilateral differences in the subchondral bone surfaces were less than 0.3mm. The method can also be potentially transferable to other relevant studies that require the accurate quantification of bone bilateral asymmetries.

Traditional and contemporary surgical approaches to the orbit

Traditional orbital approaches are nearly a century old and still comprise the foundation of techniques used today. Computer-assisted planning and intraoperative navigation have recently been reported with more prevalence in the literature. The purpose of this article was to review commonly used approaches to the orbit: old and new.

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.

Reconstruction of Post-traumatic Internal Orbital Wall Defects with Titanium Mesh

INTRODUCTION

The management of orbital injuries is one of the most interesting and difficult areas in facial trauma. The improper reconstruction of the orbit frequently results in ophthalmic complications. Though a number of materials are available for use in orbital wall reconstruction, at present titanium mesh could be considered to be the ideal orbital floor repair material.

MATERIALS AND METHODS

The study involved patients with symptomatic zygomatico-orbital fractures requiring orbital wall reconstruction. Under general anaesthesia the floor of orbit was explored and reconstructed with contoured titanium mesh after repositioning of the entrapped orbital contents. The patients were on periodic follow-up for 6 weeks where clinical and radiographic data were recorded.

RESULT

Ten male patients age ranging from 22 to 53 years (mean 29.88 years) received titanium implants for impure orbital fractures (eight patients) and pure orbital floor fractures (two patients). The main cause of fractures was road traffic accidents. They also complained of enophthalmos (n = 7), diplopia (n = 4), infraorbital nerve paresthesia (n = 6), dystopia (n = 1) and epiphora (n = 2). No implant extrusion or infection was seen. The symptoms were corrected in six patients with enophthalmos, three with diplopia, four with infraorbital nerve paresthesia and all patients with epiphora. Dystopia persisted post-surgically in one patient.

CONCLUSION

Titanium orbital implants were used to confirm titanium as a useful repair material for orbital floor fractures. Their use leads to less morbidity as no donor site operation is needed. Also it provides favourable healing as it is biocompatible.

Customized titanium reconstruction of post-traumatic orbital wall defects: a review of 22 cases

The authors present the clinical results of their method of customized reconstruction of orbital wall defects using titanium mesh or sheet. High resolution computed tomography (CT) data are imported and processed to create a three-dimensional (3D) image which is used to reconstruct the orbital defect. Mirror imaging of the air in the contralateral maxillary sinus is used to overcome artefact defects in the floor. A stereolithographic model is constructed, from which titanium mesh or sheet is shaped and sized to the required contours for implantation. Twenty-two patients were treated using this technique from 2003 to 2008. Postoperatively 10 patients reported early resolution of their diplopia. Six patients noticed significant improvement of their symptoms with mild residual diplopia in one direction only and at the extremes of gaze at final review. One patient required ocular muscle surgery. Enophthalmos resolved in eight of the nine cases. No patients developed enophthalmos or diplopia as a postoperative complication. The use of titanium mesh for orbital floor reconstruction has been shown to be safe and effective. Customized titanium implants accurately reproduce orbital contours thus restoring orbital volume. This reduces operative time and improves the functional and aesthetic outcomes of post-traumatic orbital reconstruction.

Orbitozygomatic fractures with enophthalmos: analysis of 64 cases treated late

PURPOSE

To present our treatment experience in delayed orbitozygomatic fracture with enophthalmos and compare the results of traditional surgery, navigation-guided surgery, and 3-dimensional (3D) model-guided surgery in the Departments of Oral and Maxillofacial Surgery and Ophthalmology, Shanghai Ninth People's Hospital, Shanghai, China.

PATIENTS AND METHODS

This is a retrospective review of a consecutive clinical case series. From 2008 to 2010, 64 patients diagnosed with delayed orbitozygomatic fractures with enophthalmos were treated in the departments. Computed tomography (CT) scan and ophthalmologic examination were performed before surgery. Traditional surgery and computer-assisted treatment (navigation and 3D model) were used for zygoma reduction. Three materials were applied for orbital reconstruction: hydroxyapatite (HA), porous polyethylene (Medpor; Porex Surgical Inc, Newnan, GA), and titanium mesh. Zygomatic reduction and globe projection of different treatment methods were evaluated by postoperative CT scan and clinical follow-up visits.

RESULTS

Thirty-nine cases with enophthalmos (mean, 4.96 mm) had traditional surgery for fracture reduction and orbital reconstruction, whereas the other twenty-five cases with enophthalmos (mean, 5.71 mm) had computer-assisted surgery consisting of 3D models to pre-bend the titanium mesh for orbital reconstruction and plates for fracture fixation (n = 25) and navigation-guided surgery (n = 11). Postoperative CT with 3D reconstruction showed good zygomatic reduction in 74.3% of the cases with traditional surgery, 85.7% with computer-assisted 3D models only, and 100% with navigation-guided surgery. In the traditional surgery group, 74.2% of the cases had good postoperative globe projection (≤2 mm), 19.4% had mild enophthalmos (≤3 mm), and 6.5% had moderate enophthalmos (≤4 mm). In the group undergoing computer-assisted 3D model surgery, 75% of the cases had good globe projection and 25% had mild enophthalmos. In the navigation-guided surgery group, 90.9% of the cases had good globe projection and 9.1% had mild enophthalmos. Titanium mesh was used for orbital reconstruction in 47 cases (among which, 12 combined with Medpor or HA), whereas 12 had Medpor only and 5 had HA only. Good globe projection was acquired in 74% of the cases with titanium mesh only, 83% with combined materials, 67% with Medpor only, and 20% with HA only.

CONCLUSIONS

Computer-assisted surgery can improve the treatment results of delayed orbitozygomatic fracture with enophthalmos. Navigation-guided surgery with a 3D model and titanium mesh with Medpor are the best ways to treat delayed orbitozygomatic fractures with severe enophthalmos.

[Post-traumatic orbital reconstruction comparing preformed versus non preformed titanium mesh plates]

AIM

We compared, clinically and radiologically, the accuracy and reliability of two types of titanium mesh plates used for orbital reconstruction. The first were non-preshaped mesh plates (NPMP) and the second were three-dimensionally preformed mesh plates (PMP).

METHODS

Two groups were created, each including 15 patients treated with NPMP and the second formed by 15 patients treated with PMP. The volume of each orbit was computed from coronal CT-scans using the OsiriX medical imaging software (version 3.3.2, www.osirix-viewer.com). Measurements were done for both, healthy and reconstructed sides. The other studied parameters were: sex, age, fracture distribution, and complications (diplopia and enophthalmia).

RESULTS

The orbital volume difference between the reconstructed and the healthy contralateral side was not statistically significant in either group (NPMP: p=0.991 PMP: p=0.200). The mean orbital volume of reconstructed orbits was not statistically significant in either group (NPMP: 21.76 cm(3) and PMP: 20.28 cm(3), p=0.441).

DISCUSSION

There is no difference in orbital volume reconstructions measured by the OsiriX software between non-preshaped and three-dimensionally preformed titanium mesh plates.

Comparison of collagen membranes and polydioxanone for reconstruction of the orbital floor after fractures

Orbital floor fractures, often combined with zygomatic fractures, are common fractures of the midface. Surgery of orbital fractures is done to free incarcerated or prolapsed orbital tissue and to restore the anatomic skeletal size of the orbit. Lyodura was a standard for the reconstruction of the orbital floor until cases of Creutzfeldt-Jakob disease were reported, so that polydioxanone (PDS) is widely used today. However, infections around the implant are reported. In a randomized controlled clinical study on 24 patients with orbital floor defects of approximately 1 cm, we evaluated the use of a collagen membrane compared with a PDS foil. Computed tomography controls and ophthalmologic examinations were performed after 6 months in 10 patients per group.Intraoperative complications occurred neither in the collagen membrane group nor in the PDS group. In case of orbital rim fractures, the collagen membrane could additionally cover these defects. Perioperatively and postoperatively, no complications such as infections were observed. After 6 months, computed tomography controls revealed a complete reposition of orbital tissue and even bone regeneration in both groups. Diplopia and hypoesthesia were completely reversed after half a year.Smaller defects (up to 1 cm) of the orbital floor can be restored with a PDS foil or a collagen membrane. However, for larger defects, stability may not be sufficient.

Evaluation of the application of computer-aided shape-adapted fabricated titanium mesh for mirroring-reconstructing orbital walls in cases of late post-traumatic enophthalmos

PURPOSE

Computer-aided individually shape-adapted fabricated titanium mesh for the mirroring-reconstruction of the orbit is a promising method for the correction of post-traumatic enophthalmos. The purpose of this study was to evaluate the application of this technique and assess the treatment outcomes.

PATIENTS AND METHODS

Twenty-one patients with delayed treatment of unilateral impure orbital fracture and post-traumatic enophthalmos were included in this study. Computed tomography-based mirroring-reconstruction images of the orbit were obtained for each individual to fabricate anatomically adaptive titanium mesh by computer-aided design and computer-aided manufacturing techniques. After exposing the areas of orbital defect and reducing the herniated soft tissue, the titanium mesh was inserted to reconstruct the internal orbit with a mean deep extension of 29.33 mm. Measurements were performed to assess the change in the degree of enophthalmos and orbital volume before and after surgery. Paired samples t test and Pearson correlation coefficient were employed for statistical analysis.

RESULTS

Follow-up examinations revealed that the degree of enophthalmos decreased to less than 2 mm in 11 patients, 2 to 4 mm in 9 patients, and remained greater than 7 mm in 1 patient. Statistical analysis revealed that post-traumatic enophthalmos in this series was 4.05 +/- 2.02 mm, which was associated with an orbital volume increment of 6.61 +/- 3.63 cm(3), with a regression formula of enophthalmos = 0.446 x orbital volume increment + 2.406. Orbital reconstruction effected a orbital volume decrease of 4.24 +/- 2.41 cm(3) and enophthalmos correction of 2.01 +/- 1.46 mm, the regression formula being enophthalmos = 0.586 x orbital volume decrease + 0.508. After surgery, the degree of unresolved enophthalmos was 2.03 +/- 1.52 mm, and the retained orbital volume expansion was 2.23 +/- 2.86 cm(3), and the regression formula was enophthalmos = 0.494 x orbital volume expansion + 1.415.

CONCLUSION

Application of the individual fabricated titanium mesh for orbital reconstruction reduced the trauma-induced orbital volume increment by 65% and corrected 50% of severe late enophthalmos. Additional augmentation of orbital contents was required for further correction. The related treatment parameters were suggested.

Computer planning and intraoperative navigation in cranio-maxillofacial surgery

Preoperative computer design and stereolithographic modeling combined with intraoperative navigation provide a useful guide for and possibly more accurate reconstruction of a variety of complex cranio-maxillofacial deformities. Although probably not necessary for routine use, the author's early experience confirms that of other surgeons with more than a decade of experience: computer-assisted surgery is indicated for complex posttraumatic or postablative reconstruction of the orbits, cranium, maxilla, and mandible; total temporomandibular joint replacement; orthognathic surgery; and complex dental/craniofacial implantology. Further study is needed to provide outcomes data and cost-benefit analyses for each of these indications.