Anatomical 3-dimensional Pre-bent Titanium Implant for Orbital Floor Fractures

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

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

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.

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

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

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.

Surgical repair of large orbital floor and medial wall fractures with destruction of the inferomedial strut: Initial experience with a combined endoscopy navigation technique

The application of navigation and endoscope is an area of intense interest in the surgical repair of orbital fractures. This study explored the advantages of a combined endoscopy navigation technique (ENT) for repairing large orbital floor and medial wall fractures (OFMWFs) with destruction of the inferomedial strut (IMS). Fifty-two consecutive patients with large OFMWFs with the destruction of the IMS underwent ENT-assisted surgical repair from January 2013 to February 2016. Patient demographics, causes of injury, clinical features, imaging data, and follow-up information (diplopia, ocular dysmotility, enophthalmos, infraorbital hypoesthesia, and other conditions) were collected and analyzed. Orbital volumes and implant positions were also evaluated. The median follow-up duration was 21 (range, 16-29) months. At the end of the follow-up visits, orbital reconstruction was demonstrated by orbital computed tomography. Of the 30 patients with diplopia within the 30-degree visual field of gaze, 27 (90%) reached diplopia remission. Of 40 patients, 34 (85%) achieved complete elimination of ocular dysmotility. Of 47 patients with enophthalmos of >2 mm, 43 (91%) acquired good symmetry with a mean improvement of 3.00 ± 1.00 mm. Of 33 patients, 27 (82%) recovered from infraorbital hypoesthesia. The postoperative orbital volumes of the two sides showed no significant differences (p = 0.087, paired t-test). Early surgical repair showed better outcomes of diplopia, ocular motility, and enophthalmos than late repair (p = 0.001, p = 0.007, and p = 0.000, generalized estimated equations). No patient developed surgery-related complications of visual acuity compromise, strabismus, ectropion, entropion, or lacrimal canaliculus injuries. ENT-assisted surgery appears to be safe, precise, and effective for the repair of large OFMWFs with destruction of the IMS.

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.

Controversies and Contemporary Management of Orbital Floor Fractures

Substantial controversy exists regarding the timing of intervention and management of patients with orbital floor fractures. Recent advances in computer-aided technology, including the use of 3-dimensional printing, intraoperative navigational imaging, and the use of novel implants, have allowed for improvement in prospective management modalities. As such, this article aims to review the indications and timing of repair, surgical approaches, materials used for repair, and contemporary adjuncts to repair. Indications for orbital floor fracture repair remain controversial as many of these fractures heal without intervention or adverse sequelae. Intraoperative navigation and imaging, as well as endoscopic guidance, can improve visualization of defects mitigating implant positioning errors, thereby reducing the need for secondary corrective procedures. Patient-specific implants may be constructed to fit the individual patient's anatomy using the preoperative CT dataset and mirroring the contralateral unaffected side and have been shown to improve pre-operative efficiency and minimize postoperative complications. With increased data, we can hope to form evidence-based indications for using particular biomaterials and the criteria for orbital defect characteristics, which may be best addressed by a specific surgical approach.

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

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

Facial defects reconstruction by titanium mesh bending using 3D printing technology: A report of two cases

Introduction

Facial injuries and deformities have received special attention during the previous decades for their functional, esthetic impairment, surgical challenges related to the location of the intervention, and their relationship to a lower survival rate. Moreover, there have been many surgical reconstructive methods due to the different materials and tools available and thus the final results following the surgical intervention.

Case presentation

This study was conducted on two patients with severe war injuries; they both suffered from a significant loss in one or more of the following bones: the zygomatic bone, maxilla, nasal bone, infraorbital rim, and mandible. They were treated using preshaped 3D titanium mesh implants that were made using polylactic acid (PLA) material. The final shape was identified depending on pregenerated multislice 3D modeling using computed tomography (CT) scan.

Clinical discussion and conclusion

The patient-specific titanium implants produced using polylactic acid (PLA) have been an important option for reconstructive surgical interventions in facial injuries. It has achieved a better outcome in comparison with manual bent titanium mesh in terms of anatomical symmetry, overall operating time, functional and esthetic impairment. These points helped achieve better care for both civilian and war injuries associated with bone loss.

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Facial injuries are of significant consideration especially during war time.

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Using titanium plates has increased due to its biocompatibility and rigid fixation.

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A printing model for the skull using polylactic acid is a successful approach.

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Pre-shaped mesh plates reveal better surgical outcomes.

A Stepwise Guide to Freehand Bending of Orbital Floor Mesh

Orbital fractures can often result in enophthalmos or diplopia. Orbital reconstruction with titanium meshes is the current treatment modality. Adapting the titanium orbital floor mesh is often challenging due to the complex anatomy of the orbital floor. Here, a stepwise free hand bending technique of a titanium orbital floor mesh is described. The bending can be done preoperatively, and mesh fit can be checked against a dry anatomical skull before sterilization. The methodical approach to free hand bending of titanium orbital floor mesh minimizes the intraoperative adjustments and permits quick orbital reconstruction. Trainees and less-experienced surgeons can benefit from the methodical approach to free hand bending of titanium orbital floor mesh.

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.

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.

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.

Orbital Implants in Orbital Fracture Reconstruction: A Ten-Year Series

Study Design

Retrospective comparative interventional series of all patients who had undergone orbital fracture repair by 2 senior orbital surgeons in a single tertiary trauma center from January 2005 to December 2014.

Objective

To compare the outcomes of different implants used for various types of orbital fractures.

Methods

Patients were evaluated by age, gender, etiology of fracture, clinical findings, type of fractures, and implant used. Main outcome measures included restoration of premorbid state without morbidity and complications including enophthalmos, diplopia, infraorbital hypoesthesia, and ocular motility restriction 1 year after fracture repair. Implant-related complications were collected for analysis.

Results

There were a total of 274 patients with 307 orbits reconstructed. Thirty-three (12.0%) patients sustained bilateral injuries; 58.0% (n = 178) of orbits had simple fractures (isolated orbital floor, medial wall, or combined floor and medial wall). The distribution of implants used were bioresorbable (n = 117, 38.1%) and prefabricated titanium plates (n = 98, 31.9%) depending upon the nature of fracture. Bioresorbables, titanium plate, and porous polyethylene were used significantly more than titanium mesh for simple fractures, and prefabricated anatomic titanium implants were used significantly more than the other implants for complex fractures. There was a statistically significant improvement in diplopia, enophthalmos, ocular motility, and infraorbital hypoesthesia (p-value < 0.001) 1 year following orbital fracture reconstruction.

Conclusions

When used appropriately, diverse alloplastic materials used in orbital fracture repair tailored to the indication aid orbital reconstruction outcomes with each material having its own unique characteristics.

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

BACKGROUND AND PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Restoration of the inferomedial orbital strut using a standardized three-dimensional printing implant

The inferomedial orbital strut (IOS) is the thin bony junction of the orbital medial wall and floor. Its fracture is common and leads to serious complications, including enophthalmos, globe dystopia and diplopia. However, anatomical restoration of the IOS is challenging owing to reduced structural support; sound anatomical background and accurate implants are therefore essential. The aim of the present study was to incorporate data from cadaveric orbit anatomy into three-dimensional (3D) printing technology and to reconstruct the complex orbital fracture elaborately. After averaging the data from computed tomography (CT) images of 100 adult cadavers, the dimensions of the IOS were extracted, and a tangent sphere was created using a computer-aided design program. The curves were compared with the CT data of 10 adult patients from the simulation test. Based on these data, a standardized 3D implant, 1.15 mm thick, was designed using polycaprolactone. The implant was placed in five patients with complex orbital fractures. The radius of the sphere in contact with the orbit, measuring 33.54 mm, was confirmed to be appropriate. A comparison between the normal side volume (V0) and the postoperative volume (V_post ) showed that they were statistically similar. Furthermore, a comparison between V0 and the preoperative volume (V_pre ), and V_post compared with V_pre also showed a statistically significant difference (P < 0.05). On follow-up, the preoperative ocular symptoms were resolved. The orbital data obtained from 100 cadavers provided standardized orbital anatomy, and 3D printed implants were created. The implants were anatomically accurate with regard to the orbital cavity and adequately covered the simulation model. The implant also showed satisfactory results when applied clinically in actual patients.

Application of Three-Dimensional Printing Technology for Improved Orbital-Maxillary-Zygomatic Reconstruction

The reconstruction of orbital-maxillary-zygomatic complex (OMZC) on patients suffering from trauma and space-occupying lesions is challenging due to the irregularity of craniomaxillofacial bones. To overcome the challenge in precise OMZC reconstruction, individual three-dimensional (3D) disease models and mirror-imaged 3D reconstruction models were printed on the basis of the computer tomography. Preoperative planning by rehearsing surgical procedures was made on the 3D disease models and the scaffolds including titanium and absorbable meshes or plates were anatomically premolded using the mirror-imaged 3D models as guide. Many benefits were achieved including more precise OMZC reconstruction, fluent and smooth procedures of surgeries, shorter operation time, less blood loss, and improved cosmetic outcomes of craniomaxillofacial shapes. There were no complications such as diplopia, infection, foreign body reaction, exophthalmos, enophthalmos, disordered occlusal relationship, and hematoma. And patients were satisfied with the functional and esthetic outcome during the following-up time. Therefore, OMZC reconstruction can be optimized and successful through preoperative planning and premolded scaffolds with 3D printing bone model by computer-aid design and manufacturing.

A simple method to estimate the linear length of the orbital floor in complex orbital surgery

BACKGROUND

The orbital floor (OrF) and infraorbital rim (IOR) repair in cases of complete destruction is challenging mainly due to the fact that the defect length cannot be measured. The aim of the current study is to develop a method of calculating the Orf length by using the gender and the lengths of the medial, superior and lateral orbital walls (OrW) of the same orbit.

MATERIAL AND METHODS

Ninety-seven (59 male and 38 female) European adult dry skulls were classified according to age: 20-39, 40-59 and 60 years and above. The length of each OrW was measured by using the direct distance between the optic foramen and a landmark in each orbital rim.

RESULTS

A side asymmetry was detected for the lengths of the inferior, superior and medial OrW. Although a gender dimorphism was detected, no correlation with the age was found. Using the Stepwise multiple regression analysis two formulas were developed, one for the right and one for the left OrF with coefficient of determination R² 0.43 and 0.57, respectively.

CONCLUSIONS

The proposed formulas represent a simple, applicable and individualized method to calculate the OrF linear length in cases of complete destruction of the IOR and OrF, with accuracy and without the use of expertise material. Such data may improve the surgery planning of orbital floor fractures and complex orbital reconstructions.

Orbital Fracture Reconstruction Using Prebent, Anatomic Titanium Plates: Technical Tips to Avoid Complications

Orbital fractures are common. In patients where there is significant loss of the medial wall and orbital floor, anatomic prebent 3-dimensional plates allow efficacious restoration of orbital volume. However, the large size of these plates can result in technical difficulties with plate placement, especially in fractures with complete loss of 2 walls of the orbit. In this article, the authors review the pertinent anatomy of the bony orbit with respect to fracture and landmarks in fracture reduction. The authors also note the 3 most commonly encountered problems with the placement of anatomic plates: poor exposure, failure to identify the posterior ledge for the plate, and rotational issues with plate placement resulting in impingement. Technical tips are given to help overcome these issues intraoperatively.

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.

A novel anatomical thin titanium mesh plate with patient-matched bending technique for orbital floor reconstruction

This study developed an anatomical thin titanium mesh (ATTM) plate for Asian orbital floor fracture based on the medical image database. The computer aided stamping analysis was performed on four hole/slot patterns included the control type without hole design, circular hole pattern, slot pattern and hole/slot hybrid patterns within the ATTM plate with upper/lower dies of averaged orbital cavity reconstruction models. The curved-fan ATTM plate with 0.4 mm thickness was manufactured and pre-bent using a patient matched stamping process to verify its feasibility and the interfacial fitness between the plate and bone on the orbital floor fracture model. The stamping analysis found that the hole/slot hybrid patterns design resulted in the most favorable performance among all designs owing to the lowest maximum von-Mises stress/strain and spring-back value. The interfacial adaption results test showed that the average patient-matched stamping bending gap size was only 0.821 mm and the operative time was about 8 s. This study concluded that the curved-fan ATTM plate with hole/slot hybrid pattern design and patient-matched pre-bent technique can fit the ATTM plate/orbital cavity interface well, decrease unstable fracture segment mobility and improve the overall reduction efficiency.

Is there more to the clinical outcome in posttraumatic reconstruction of the inferior and medial orbital walls than accuracy of implant placement and implant surface contouring? A prospective multicenter study to identify predictors of clinical outcome

PURPOSE

Reconstruction of orbital wall fractures is demanding and has improved dramatically with the implementation of new technologies. True-to-original accuracy of reconstruction has been deemed essential for good clinical outcome, and reasons for unfavorable clinical outcome have been researched extensively. However, no detailed analysis on the influence of plate position and surface contour on clinical outcome has yet been published.

MATERIALS AND METHODS

Data from a previous study were used for an ad-hoc analysis to identify predictors for unfavorable outcome, defined as diplopia or differences in globe height and/or globe projection of >2 mm. Presumed predictors were implant surface contour, aberrant implant dimension or position, accuracy of reconstructed orbital volume, and anatomical fracture topography according to the current AO classification.

RESULTS

Neither in univariable nor in multivariable regression models were unfavorable clinical outcomes associated with any of the presumed radiological predictors, and no association of the type of implant, i.e., standard preformed, CAD-based individualized and non-CAD-based individualized with its surface contour could be shown.

CONCLUSION

These data suggest that the influence of accurate mechanical reconstruction on clinical outcomes may be less predictable than previously believed, while the role of soft-tissue-related factors may have been underestimated.

Examination of Local Periosteal Microcirculation After Application of Absorbable and Nonabsorbable Membranes

The use of different membranes is common in dentoalveolar surgery. Absorbable and nonabsorbable membranes are used, often beneath the periosteum, to fulfil different functions (as barriers, patches, or spacers). It is still unclear to what extent such membranes affect the biology of the periosteum and what role is played by piezoelectric devices during preparation of the periosteum. We placed two different membranes (absorbable and nonabsorbable) underneath the periosteum of rat calvaria. We prepared the periosteum using different methods (piezoelectric device vs mechanical device). We then examined and analyzed periosteal microcirculation over a period of 28 days. A clear difference was observed between the two methods when used with absorbable membranes: The piezoelectric device offered advantages. Absorbable membranes maintain considerably more local periosteal microcirculation and should be given preference. In addition, we observed an advantage to using a piezoelectric device for periosteal dissection. Therefore, this method should also be used more widely.

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.

Clinical effects of 3-D printing-assisted personalized reconstructive surgery for blowout orbital fractures

PURPOSE

One of the key challenges during orbital fracture reconstructive surgery, due to the complex anatomy of the orbit, is shaping and trimming the precise contour of the implants. The objectives of this study were to describe and evaluate the use of a three-dimensional (3-D) printing technique for personalized reconstructive surgery for repairing orbital fractures.

METHODS

A total of 29 cases which had 3-D technique-assisted surgical reconstruction, and 27 cases which had traditional surgery, were retrospectively analyzed. Preoperative and postoperative CT images were measured using MIMICS software, and the contour of the fracture zone and the Medpor-titanium implant were analyzed and compared. The surgical duration was also compared between the two groups.

RESULTS

There were statistically significant differences in the maximum width, depth and area between fracture zone and implant between the two groups, with the absolute value in the 3-D group markedly lower as compared to the control group. In addition, the difference in the medial-inferior wall angle between the surgical eye and healthy eye was also statistically significant between the groups. The average surgical duration in the 3-D group was substantially shorter than in the control group. Additionally, the postoperative clinical evaluation in the 3-D group was superior to that of the control group.

CONCLUSION

The 3-D printing technique is of great value for predicting the precise fracture zone before, and during, personalized surgery, and can help surgeons achieve accurate anatomical reconstruction for repairs of blowout orbital fractures. Moreover, the simulated bone template produced by 3-D printing models allows for "true-to-original" orbital reconstruction, which can shorten the surgical duration and improve the accuracy and safety of the operation.

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.

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.

Patient-Specific Orbital Implants: Development and Implementation of Technology for More Accurate Orbital Reconstruction

Fracture of the orbital floor is commonly seen in facial trauma. Accurate anatomical reconstruction of the orbital floor contour is challenging. The authors demonstrate a novel method to more precisely reconstruct the orbital floor on a 50-year-old female who sustained an orbital floor fracture following a fall. Results of the reconstruction show excellent reapproximation of the native orbital floor contour and complete resolution of her enopthalmos and facial asymmetry.

Orbital reconstruction

PURPOSE OF REVIEW

Post-traumatic orbital reconstruction is a complex issue that involves both the soft tissue and bony injury. The current literature focuses primarily on bony reconstruction, with fewer investigators evaluating soft-tissue injuries. This article will review recent advances in orbital reconstruction, including presurgical planning software, intra-operative navigation, patient-specific implants, and intra-operative imaging.

RECENT FINDINGS

Traditional techniques for diagnosis and orbital injuries continue to be refined; however, advances in computer-aided surgery are allowing surgeons to significantly improve the anatomic accuracy of orbital reconstruction.

SUMMARY

While not all surgeons currently have access to computer-aided applications for orbital reconstruction, these techniques will continue to be refined, resulting in lower cost and greater access.

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.

Trauma of the midface

Fractures of the midface pose a serious medical problem as for their complexity, frequency and their socio-economic impact. Interdisciplinary approaches and up-to-date diagnostic and surgical techniques provide favorable results in the majority of cases though. Traffic accidents are the leading cause and male adults in their thirties are affected most often. Treatment algorithms for nasal bone fractures, maxillary and zygomatic fractures are widely agreed upon whereas trauma to the frontal sinus and the orbital apex are matter of current debate. Advances in endoscopic surgery and limitations of evidence based gain of knowledge are matters that are focused on in the corresponding chapter. As for the fractures of the frontal sinus a strong tendency towards minimized approaches can be seen. Obliteration and cranialization seem to decrease in numbers. Some critical remarks in terms of high dose methylprednisolone therapy for traumatic optic nerve injury seem to be appropriate. Intraoperative cone beam radiographs and preshaped titanium mesh implants for orbital reconstruction are new techniques and essential aspects in midface traumatology. Fractures of the anterior skull base with cerebrospinal fluid leaks show very promising results in endonasal endoscopic repair.

The Role of Computer-Assisted Technology in Post-Traumatic Orbital Reconstruction: A PRISMA-driven Systematic Review

Post-traumatic orbital reconstruction remains a surgical challenge and requires careful preoperative planning, sound anatomical knowledge and good intraoperative judgment. Computer-assisted technology has the potential to reduce error and subjectivity in the management of these complex injuries. A systematic review of the literature was conducted to explore the emerging role of computer-assisted technologies in post-traumatic orbital reconstruction, in terms of functional and safety outcomes. We searched for articles comparing computer-assisted procedures with conventional surgery and studied outcomes on diplopia, enophthalmos, or procedure-related complications. Six observational studies with 273 orbits at a mean follow-up of 13 months were included. Three out of 4 studies reported significantly fewer patients with residual diplopia in the computer-assisted group, while only 1 of the 5 studies reported better improvement in enophthalmos in the assisted group. Types and incidence of complications were comparable. Study heterogeneities limiting statistical comparison by meta-analysis will be discussed. This review highlights the scarcity of data on computer-assisted technology in orbital reconstruction. The result suggests that computer-assisted technology may offer potential advantage in treating diplopia while its role remains to be confirmed in enophthalmos. Additional well-designed and powered randomized controlled trials are much needed.

Virtual Surgical Planning for Orbital Reconstruction

The advent of computer-assisted technology has revolutionized planning for complex craniofacial operations, including orbital reconstruction. Orbital reconstruction is ideally suited for virtual planning, as it allows the surgeon to assess the bony anatomy and critical neurovascular structures within the orbit, and plan osteotomies, fracture reductions, and orbital implant placement with efficiency and predictability. In this article, we review the use of virtual surgical planning for orbital decompression, posttraumatic midface reconstruction, reconstruction of a two-wall orbital defect, and reconstruction of a large orbital floor defect with a custom implant. The surgeon managing orbital pathology and posttraumatic orbital deformities can benefit immensely from utilizing virtual planning for various types of orbital pathology.

Rapid prototyping-assisted maxillofacial reconstruction

Rapid prototyping (RP) technologies have found many uses in dentistry, and especially oral and maxillofacial surgery, due to its ability to promote product development while at the same time reducing cost and depositing a part of any degree of complexity theoretically. This paper provides an overview of RP technologies for maxillofacial reconstruction covering both fundamentals and applications of the technologies. Key fundamentals of RP technologies involving the history, characteristics, and principles are reviewed. A number of RP applications to the main fields of oral and maxillofacial surgery, including restoration of maxillofacial deformities and defects, reduction of functional bone tissues, correction of dento-maxillofacial deformities, and fabrication of maxillofacial prostheses, are discussed. The most remarkable challenges for development of RP-assisted maxillofacial surgery and promising solutions are also elaborated.

Mirror-Imaged Rapid Prototype Skull Model and Pre-Molded Synthetic Scaffold to Achieve Optimal Orbital Cavity Reconstruction

PURPOSE

Reconstruction of traumatic orbital wall defects has evolved to restore the original complex anatomy with the rapidly growing use of computer-aided design and prototyping. This study evaluated a mirror-imaged rapid prototype skull model and a pre-molded synthetic scaffold for traumatic orbital wall reconstruction.

PATIENTS AND METHODS

A single-center retrospective review was performed of patients who underwent orbital wall reconstruction after trauma from 2012 to 2014. Patients were included by admission through the emergency department after facial trauma or by a tertiary referral for post-traumatic orbital deformity. Three-dimensional (3D) computed tomogram-based mirror-imaged reconstruction images of the orbit and an individually manufactured rapid prototype skull model by a 3D printing technique were obtained for each case. Synthetic scaffolds were anatomically pre-molded using the skull model as guide and inserted at the individual orbital defect. Postoperative complications were assessed and 3D volumetric measurements of the orbital cavity were performed. Paired samples t test was used for statistical analysis.

RESULTS

One hundred four patients with immediate orbital defect reconstructions and 23 post-traumatic orbital deformity reconstructions were included in this study. All reconstructions were successful without immediate postoperative complications, although there were 10 cases with mild enophthalmos and 2 cases with persistent diplopia. Reoperations were performed for 2 cases of persistent diplopia and secondary touchup procedures were performed to contour soft tissue in 4 cases. Postoperative volumetric measurement of the orbital cavity showed nonsignificant volume differences between the damaged orbit and the reconstructed orbit (21.35 ± 1.93 vs 20.93 ± 2.07 cm(2); P = .98). This protocol was extended to severe cases in which more than 40% of the orbital frame was lost and combined with extensive soft tissue defects.

CONCLUSION

Traumatic orbital reconstruction can be optimized and successful using an individually manufactured rapid prototype skull model and a pre-molded synthetic scaffold by computer-aid design and manufacturing.

Increasing the accuracy of orbital reconstruction with selective laser-melted patient-specific implants combined with intraoperative navigation

PURPOSE

Advances in technology have allowed increasing degrees of accuracy in the treatment of orbital deformities. The purpose of this study was to compare the accuracy of pre-bent titanium mesh (PBTM) and selective laser-melted patient-specific implants (PSIs) in unilateral orbital reconstruction after traumatic injury. The authors hypothesized that selective laser-melted PSIs would more accurately reconstruct the orbit.

MATERIALS AND METHODS

A retrospective review of 34 cases of primary reconstruction of unilateral orbital fractures treated using selective laser-melted PSIs (group 1, n = 17) or PBTM (group 2, n = 17) was performed. The primary outcome measurements were orbital volume excess and the anterior, medial, and posterior intraorbital angles. The Mann-Whitney U test was used to assess the difference in orbital volume and angular deviation between the 2 groups. The level of statistical significance was set at .05. All P values were 2-sided.

RESULTS

The comparison of mean values for the 2 groups showed significant differences for the anterior angle (PBTM: mean, 11.3; standard deviation [SD], 1.8; PSI: mean, 4.1; SD, 0.7; P = .001), but not the medial (PBTM: mean, 11.6; SD, 2.0; PSI: mean, 8.2; SD, 1.9; P = .170) and posterior (PBTM: mean, 10.8, SD, 2.8; PSI: mean, 8.2, SD, 1.4; P = .760) angles between the unaffected and reconstructed orbits. The postoperative difference in volume between the unaffected and reconstructed orbits differed significantly between the 2 study groups (PBTM: mean, 0.6; SD, 0.1; PSI: mean, 0.4; SD, 0.1; P = .029).

CONCLUSION

The results of this study suggest that complex orbital fractures can be reconstructed with an even higher degree of accuracy with selective laser-melted PSIs than with PBTM.