Biomaterials for reconstruction of the internal orbit

Surgical treatment of orbital tumors in a single center: Analysis and results

Background

Orbital tumors, arising within the bony orbit and its contents, present diverse challenges due to their varied origins and complex anatomical context. These tumors, classified as primary, secondary, or metastatic, are further subdivided into intraconal and extraconal based on their relationship with the muscle cone. This classification significantly influences surgical approach and management. This study highlights surgical experiences with orbital tumors, underscoring the importance of tailored surgical approaches based on the lesion's site and its proximity to the optic nerve.

Methods

This retrospective study at the National Institute of Cancer's Head and Neck Department (2005-2014) analyzed 29 patients with orbital tumors treated with surgery, radiotherapy, chemotherapy, or combinations of them. Patient demographics, tumor characteristics, and treatment responses were evaluated using computed tomography (CT), magnetic resonance imaging, and positron emission tomography-CT imaging. Malignant tumors often required orbital exenteration and reconstruction, highlighting the study's commitment to advancing orbital tumor treatment.

Results

29 patients (18 females and 11 males, age 18-88 years, mean 53.5 years) with orbital tumors exhibited symptoms such as decreased vision and exophthalmos. Tumors included primary lesions like choroidal melanoma and secondary types like epidermoid carcinoma. Treatments varied, involving a multidisciplinary team for surgical approaches like exenteration, with follow-up from 1 to 9 years. Radiotherapy and chemotherapy were used for specific cases.

Conclusion

Our study underscores the need for a multidisciplinary approach in treating orbital tumors, involving various surgical specialists and advanced technologies like neuronavigation for tailored treatment. The integration of surgery with radiotherapy and chemotherapy highlights the effectiveness of multidimensional treatment strategies.

Thin PDS Foils Represent an Equally Favorable Restorative Material for Orbital Floor Fractures Compared to Titanium Meshes

Orbital floor fractures (OFFs) are common injuries of the midface and may result in long-term complications. The aim of this study was to compare two restoration materials, PDS foils and titanium meshes, with regards to (1) clinical outcome and (2) reduction in orbital volume. The monocentric discovery cohort was analyzed retrospectively and included 476 patients with OFFs treated between 2010 and 2020. A subcohort of 104 patients (study cohort) with isolated OFFs and available high-resolution imaging material was used for volume measurements. Postoperative complications were not significantly different between patients treated with different restoration materials. Prevalence of revision surgery was significantly higher in patients treated with thick PDS foils (25 mm). OFFs treated with PDS foils and titanium meshes showed a significant reduction in orbital volume (p = 0.0422 and p = 0.0056, respectively), however, this volume decrease was significantly less pronounced in patients treated with PDS foils alone (p = 0.0134). Restoration using PDS foil in an isolated OFF reduces the orbital volume to a lesser extent than titanium mesh. Class III patients according to the classification of Jaquiéry with a missing bony ledge medial to the infraorbital fissure particularly benefit from restoration with PDS foils due to a lower reduction in the orbital volume. Regarding short- and long-term postoperative complications, a PDS foil thickness of 0.15 mm appears equivalent to titanium mesh in the treatment of OFFs.

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.

Management of orbital floor fractures in France: Results of a national online survey

INTRODUCTION

Orbital floor fractures (OFF) are common facial trauma injuries, and there are no official guidelines for their medical and surgical management. The aim of this study was to provide an overview of the management of OFF in France.

MATERIALS AND METHODS

An online questionnaire was sent to 144 surgeons at the 88 French centers involved in the management of OFF (2019 data from the National Health Insurance Body). The questions related to the preoperative clinical and radiographic examinations, the criteria for surgical indication, the materials used, and the elements of the postoperative period.

RESULTS

Ultimately, 42 questionnaires were analyzed (32 from oral and maxillofacial surgeons (OMFS), 8 from ophthalmologists, and 2 from ENT or plastic surgeons). For 69% of the surgeons, a systematic ophthalmological examination was carried out, 3-7 days after the trauma, and based on a Lancaster test or visual acuity (97.6% and 83.3% of the responders, respectively). The most important criteria for the therapeutic decision were diplopia or oculomotor disorder that persisted for more than 7 days (76.2%), clinical enophthalmos (54.8%), a large fracture (52.4%), and ptosis of the orbital content on CT scan (38.1%). The mean surgical delay was 7-15 days for 54.8% of the responders. Resorbing sheets were the preferred materials to repair small fractures, while larger fractures required alloplastic implants (titanium mesh).

CONCLUSION

This survey confirms the diversity of practices in France regarding the management of OFF. Further studies are needed before guidelines can be developed.

Management of Orbital Floor Fractures: Our Experience in 10 Years

Purpose

Orbital floor Fractures are the most common fractures involving the facial skeleton and usually occurs after traumatic events. The reconstruction of the orbital floor can be performed with different biocompatible materials. The aim of our retrospective study is to analyze the short- and long-term outcomes of surgically treated patients based on the material used to repair the orbital floor.

Methods

We enrolled 146 patients hospitalized for orbital floor fractures in the Maxillofacial Surgery Unit of the Federico II University of Naples from 1 to 2010 to July 2020. All the fractured orbital floors were reconstructed with non-resorbable (Titanium Mesh, SynPor, SuPor and MedPor implants) or resorbable (collagen membrane, bovinum pericardium membrane, autologous bone graft) materials.

Results

We utilized non-resorbable materials in 56% (82 cases) and resorbable implants in 44% (64 cases). An improvement of the preoperative symptomatology and an aesthetical good outcome was achieved in most cases.

Conclusions

Data obtained supports that both resorbable and non-resorbable materials for orbital floor reconstruction are a safe and effective alternatives and offer satisfactory results in functional and aesthetic evaluations.

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.

"6 Anatomical Landmarks" Technique for Satisfactory Free-Hand Orbital Reconstruction With Standard Preformed Titanium Mesh

Study Design

Retrospective study.

Objective

Resolution of clinical signs and symptoms following orbital fractures depends on the accurate restoration of the orbital volume. Computer-Assisted procedures and Patient Specific Implants represent modern solutions, but they require additional resources. A more reproducible option is the use of standard preformed titanium meshes, widely available and cheaper; with their use quality of results is proportional to the accuracy with which they are positioned. This work identifies 6 reproducible and constant anatomical landmarks, as an intraoperative guide for the precise positioning of titanium preformed meshes.

Methods

90 patients treated at the Maxillofacial Surgery Department, Niguarda Trauma Center, Milan, for unilateral orbital reconstruction (January 2012 to December 2018), were studied. In all cases reconstruction was performed respecting the 6 proposed anatomical landmarks. The outcomes analyzed are: post-operative CT adherence to the 6 anatomical markers and symmetry achieved respect to controlateral orbit; number/year of re-interventions and duration of surgery; resolution of clinical defects (at least 12-months follow-up); incidence of complications.

Results

Satisfactory results were obtained in terms of restoration of orbital size, shape and volume. Clinical defects early recovered with a low incidence of complications and re-interventions. Operating times and radiological accuracy have shown a progressive improvement during years of application of this technique.

Conclusions

The proposed "6 anatomical landmarks" is an easy free-hand technique that allows everyone to obtain high levels of reconstructive accuracy and it should be a skill of all surgeons who deal with orbital reconstruction in daily clinical activity.

Isolated pure orbital blowout fracture - A rare case report

Rationale:

An orbital fracture is said to be a pure blowout when it affects only one internal orbital wall and does not compromise the orbital rim. Pure blowout fracture of the orbital floor without any other associated facial bone fracture is uncommon.

Patient Concerns:

The patient with a history of assault presented with complaints of blurring of vision and diplopia.

Diagnosis:

Computed tomography of paranasal sinus scans and ophthalmologic examination confirmed the right orbital floor fracture.

Treatment:

Herniated orbital contents were retrieved and the orbital floor was reconstructed with titanium mesh under general anaesthesia.

Outcomes:

The patient was followed up regularly for six months and showed no signs of any visual disturbances.

Take-away Lessons:

Although orbital floor fractures are commonly associated with zygomaticomaxillary complex and midface fractures, it is uncommon as an isolated finding in facial trauma. It can be easily misdiagnosed and left untreated, which can give rise to future complications.

Approach to Orbital Fractures After Athletic Injuries

The bony orbit is commonly involved in athletic injuries. Evaluation should include a comprehensive history and ocular examination. Computed tomography imaging is the gold standard for diagnostic testing. Urgent surgical intervention for orbital floor fractures should occur after "white eye" trapdoor fractures or if oculocardiac response occurs. Most orbital fractures do not require urgent intervention and repair can be completed within 2 weeks of injury. There are many approaches to repair orbital fractures, and consideration of techniques depends on the unique fracture pattern. Intraoperative computed tomography has become frequently used and can lead to increased identification of plate malpositioning intraoperatively.

Cathelicidin LL37 Promotes Osteogenic Differentiation in vitro and Bone Regeneration in vivo

Different types of biomaterials have been used to repair the defect of bony orbit. However, exposure and infections are still critical risks in clinical application. Biomaterials with characteristics of osteogenesis and antibiosis are needed for bone regeneration. In this study, we aimed to characterize the antimicrobial effects of cathelicidin-LL37 and to assess any impacts on osteogenic activity. Furthermore, we attempted to demonstrate the feasibility of LL37 as a potential strategy in the reconstruction of clinical bone defects. Human adipose-derived mesenchyme stem cells (hADSCs) were cultured with different concentrations of LL37 and the optimum concentration for osteogenesis was selected for further in vitro studies. We then evaluated the antibiotic properties of LL37 at the optimum osteogenic concentration. Finally, we estimated the efficiency of a PSeD/hADSCs/LL37 combined scaffold on reconstructing bone defects in the rat calvarial defect model. The osteogenic ability on hADSCs in vitro was shown to be dependent on the concentration of LL37 and reached a peak at 4 μg/ml. The optimum concentration of LL37 showed good antimicrobial properties against Escherichia coli and Staphylococcus anurans. The combination scaffold of PSeD/hADSCs/LL37 showed superior osteogenic properties compared to the PSeD/hADSCs, PSeD, and control groups scaffolds, indicating a strong bone reconstruction effect in the rat calvarial bone defect model. In Conclusion, LL37 was shown to promote osteogenic differentiation in vitro as well as antibacterial properties. The combination of PSeD/hADSCs/LL37 was advantageous in the rat calvarial defect reconstruction model, showing high potential in clinical bone regeneration.

TNF-α-Inhibition Improves the Biocompatibility of Porous Polyethylene Implants In Vivo

Background:

To improve the biocompatibility of porous polyethylene (PPE) implants and expand their application range for reconstructive surgery in poorly vascularized environments, implants were coated with tumor necrosis factor α (TNFα) inhibitor Etanercept. While approved for systemic application, local application of the drug is a novel experimental approach. Microvascular and mechanical integration as well as parameters of inflammation were analyzed in vivo.

Methods:

PPE implants were coated with Etanercept and extracellular matrix (ECM) components prior to implantation into dorsal skinfold chambers of C57BL/6 mice. Fluorescence microscopy analyses of angiogenesis and local inflammatory response were thrice performed in vivo over a period of 14 days to assess tissue integration and biocompatibility. Uncoated implants and ECM-coated implants served as controls.

Results:

TNFα inhibition with Etanercept led to a reduced local inflammatory response: leukocyte-endothelial cell adherence was significantly lowered compared to both control groups (n = 6/group) on days 3 and 14, where the lowest values were reached: 3573.88 leukocytes/mm-2 ± 880.16 (uncoated implants) vs. 3939.09 mm-2 ± 623.34 (Matrigel only) vs. 637.98 mm-2 + 176.85 (Matrigel and Etanercept). Implant-coating with Matrigel alone and Matrigel and Etanercept led to significantly higher vessel densities 7 and 14 days vs. 3 days after implantation and compared to uncoated implants. Mechanical implant integration as measured by dynamic breaking strength did not differ after 14 days.

Conclusion:

Our data show a reduced local inflammatory response to PPE implants after immunomodulatory coating with Etanercept in vivo, suggesting improved biocompatibility. Application of this tissue engineering approach is therefore warranted in models of a compromised host environment.

Electronic supplementary material

The online version of this article (10.1007/s13770-020-00325-w) contains supplementary material, which is available to authorized users.

A prospective study of resolution of post-traumatic orbital complications using PRECLUDE® MVP: A randomized controlled trial

Orbital fractures alone represent 10% up to 25% of all facial fractures, but when they are associated with other fractures of the middle-third of the face, their incidence can increase up to 55%. This study aimed to identify whether the size of the orbital defect based on the classification by Jaquiéry et al. influenced the resolution of post-traumatic complications after orbital wall reconstruction using PRECLUDE®MVP alone or in combination with a titanium mesh or autogenous bone graft. Thirty-five orbits were categorized into four groups on the basis of the size of the defect and the operative techniques: group 1 contained 16 Jaquiéry class I orbits treated only with PRECLUDE®MVP; group 2 included eight class II orbits treated with PRECLUDE®MVP along with autogenous bone graft harvested from the calvaria or a titanium mesh; group 3 included five class III orbits and group 4 included six class IV orbits that were treated the same way as those in group 2. Spearman correlation showed that the use PRECLUDE®MVP didn't improve the post traumatic complications for big orbital defects due to the three-dimensional anatomical changes that occurred by neurologic lesions and lipolysis of the orbital contents.

Reconstruction of the orbital floor using supercritical CO2 decellularized porcine bone graft

Orbital floor fractures subsequently lead to consequences such as diplopia and enophthalmos. The graft materials used in orbital floor fractures varied from autografts to alloplastic grafts, which possess certain limitations. In the present study, a novel porcine bone matrix decellularized by supercritical CO2 (scCO2), ABCcolla® Collagen Bone Graft, was used for the reconstruction of the orbital framework. The study was approved by the institutional review board (IRB) of Kaohsiung Medical University Chung-Ho Memorial Hospital (KMUH). Ten cases underwent orbital floor reconstruction in KMUH in 2019. The orbital defects were fixed by the implantation of the ABCcolla® Collagen Bone Graft. Nine out of ten cases used 1 piece of customized ABCcolla® Collagen Bone Graft in each defect. The other case used 2 pieces of customized ABCcolla® Collagen Bone Graft in one defect area due to the curved outline of the defect. In the outpatient clinic, all 10 cases showed improvement of enophthalmos on CT (computerized tomography) at week 8 follow-up. No replacement of implants was needed during follow-ups. To conclude, ABCcolla® Collagen Bone Graft proved to be safe and effective in the reconstruction of the orbital floor with high accessibility, high stability, good biocompatibility, low infection rate and low complication rate.

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.

Review of Orbital Fractures in an Urban Level I Trauma Center

Objective

To perform a comprehensive review and analysis of surgically treated orbital fractures.

Study Design

Retrospective cohort chart review study for surgically treated orbital fractures during 5 years.

Results

A total of 173 patients (average age 41.6 years) were diagnosed with orbital fractures. Most were male with a ratio of 3.3:1. Most fractures were caused by assault (39.3%); 22.5% of the cases were bilateral. The left orbit (40.5%) was fractured more than the right. The orbital floor (97.1%) was the most common anatomic location and the maxilla (65.3%) was the most commonly involved bone. The average time from trauma to surgical intervention was 8.7 ± 14.6 days and the average time from surgical intervention to discharge was 5.1 ± 9.0 days. The transconjunctival incision (63%) was the most commonly used incision, and nonresorbable implant (92.7%) was the most commonly used implant. Finally, the length of stay for the repair of a simple orbital fracture was less than for complex orbital fracture (1.5 days and 5.9 days, respectively).

Conclusion

Understanding the patterns and mechanisms of injury associated with orbital fractures can assist in developing standardized treatment protocols across all surgical specialties. This would ultimately allow for a uniform high quality of surgical care for patients with maxillofacial fractures.

Extent of Inflammation and Foreign Body Reaction to Porous Polyethylene In Vitro and In Vivo

BACKGROUND/AIM

High-density porous polyethylene (PP) offers possibilities for reconstruction in craniofacial surgery. The purpose of this study was to evaluate the extent of inflammation and foreign body reactions to PP in vitro and in vivo.

MATERIALS AND METHODS

Cell attachment, proliferation and expression of inflammatory cytokines were assessed using murine macrophages (RAW 264.7) on two different PP materials in vitro. In vivo, Balb/c mice received PP implants at their dorsum. After sacrifice, samples were analyzed histologically and real-time PCR was used to assess expression of inflammatory cytokines.

RESULTS

Cells showed a significantly decreased proliferation (p<0.001) after 48 h and a significantly increased expression of TNF-α (p<0.05) at 24, 48 and 72 h. All animals showed foreign body cell reactions and signs of chronic inflammation. Expression of all but one of the investigated cytokines dropped to non-significant levels after an initial increase.

CONCLUSION

Application of porous polyethylene can cause local chronic inflammatory reactions. Although clinical application seems to be immunologically safe, indication and risks should be evaluated carefully when using PP implants.

Four Practical Reconstructive Techniques Using the Transantral Approach to the Orbital Floor Without the Need for an Endoscope

Fractures of the orbital floor have traditionally been treated through transorbital approaches. Transconjunctival approaches risk entropion, whereas transcutaneous approaches risk ectropion or hypertrophic scarring. The intraoral transantral approach to the orbital floor has the advantage of minimizing the risk of any eyelid changes while providing appropriate access to reduce the herniated orbital contents and restore orbital volume. This article describes 4 plating methods for reconstructing a fractured orbital floor using a transantral approach. Many prior descriptions of transantral treatment of the orbital floor have relied heavily on the use of an endoscope. This article describes an osteotomy technique that does not require an endoscope but requires only a high-quality headlight for visualization.

Vitronectin promotes the vascularization of porous polyethylene biomaterials

Rapid implant vascularization is a prerequisite for successful biomaterial engraftment. Vitronectin (VN) is a matricellular glycoprotein well known for its capability to interact with growth factors, proteases, and protease inhibitors/receptors. Since such proteins are highly relevant for angiogenic processes, we hypothesized that VN contributes to the tissue integration of biomaterials. Employing different in vivo and ex vivo microscopy techniques, engraftment of porous polyethylene (PPE) implants was analyzed in the dorsal skinfold chamber model in wild-type (WT) and VN^-/- mice. Upon PPE implantation, vascularization of this biomaterial was severely compromised in animals lacking this matricellular protein. Proteome profiling revealed that VN deficiency does not cause major changes in angiogenic protein composition in the implants suggesting that VN promotes PPE vascularization via mechanisms modulating the activity of angiogenic factors rather than by directly enriching them in the implant. Consequently, surface coating with recombinant VN (embedded in Matrigel®) accelerated implant vascularization in WT mice by enhancing the maturation of a vascular network. Thus, VN contributes to the engraftment of PPE implants by promoting the vascularization of this biomaterial. Surface coating with VN might provide a promising strategy to improve the vascularization of PPE implants without affecting the host's integrity. STATEMENT OF SIGNIFICANCE: Porous polyethylene (PPE) is a biomaterial frequently used in reconstructive surgery. The proper vascularization of PPE implants is a fundamental prerequisite for its successful engraftment in host tissue. Although the overall biocompatibility of PPE is good, there are less favorable application sites for its use in tissue reconstruction mostly characterized by low blood supply. Employing advanced in vivo microscopy methods and proteomic analyses in genetically engineered mice, we here describe a previously unrecognized function of vitronectin (VN) that enables this abundantly present glycoprotein to particularly promote the vascularization of PPE biomaterial. These properties of VN specifically facilitate the formation of a dense vessel network within the implant which relies on modulating the activity of angiogenic mediators rather than on the enrichment of these factors in the implant. Consequently, surface coating with this matricellular protein effectively accelerated and intensified implant vascularization which might be beneficial for its implementation at unfavorable sites for implantation without affecting the host's integrity.

Enhanced radiographic visualization of resorbable foils for orbital floor reconstruction: A proof of principle

PURPOSE

Despite the advantages and broad applications of alloplastic resorbable implants, postoperative radiological control is challenging due to its radiolucency. The aim of the present study was to evaluate the radiographic visibility of newly developed materials for orbital floor reconstruction.

MATERIALS AND METHODS

The radiographic visibility of four different material combinations consisting of poly-(L-lactic acid)/poly-glycolic acid (PLLA/PGA) or poly(D,L-lactic acid) (PDLLA) enriched with magnesium (Mg), hydroxyapatite (HA) or β-tricalcium phosphate (β-TCP) with various layers of thicknesses (0.3, 0.6, and 1 mm), surgically placed above the orbital floor of a human head specimen, was evaluated using computed tomography (CT) and cone beam computed tomography (CBCT). The visibility was rated on a scale of 0-10 in CT/CBCT and by Hounsfield Units in CT for each subject.

RESULTS

All of the materials were clearly detectable in CT scans. Visibility was significantly higher (p < 0.001) in the standard soft tissue window (mean score: 7.3, ranging from 2 to 10) in comparison to the standard bone window (mean score: 5.2, ranging from 1 to 10). In CBCT (mean score: 3.3, ranging from 0 to 7), there was significantly lower but still sufficient visibility of the materials compared to the CT soft tissue window (p < 0.001) and CT bone window (p < 0.001). Comparing the different materials' visibility among the group of same layer thicknesses with each other, in the majority of cases, PDLLA enriched with β-TCP appeared to be most visible in both CT and CBCT.

CONCLUSION

The incorporation of radiopaque elements to PLLA/PGA and PDLLA polymers is a promising strategy to improve their visibility in CT and CBCT. Our data suggest that the reconstruction of the orbital floor with these new materials could provide an advantageous postoperative radiographic control.

Reconstruction of Orbital Floor With Auricular Concha

Orbital floor fractures of varying sizes commonly occur after orbital injuries and remain a serious challenge. Serious complications of such fractures include enopthalmos, restriction of extraocular movement, and diplopia. There is a dearth of literature that can be applied widely, easily, and successfully in all such situations, and therefore there is no consensus on the treatment protocol of this pathology yet. Autogenous grafts and alloplastic and allogenic materials with a wide variety of advantages and disadvantages have been discussed. The value of preoperative and postoperative ophthalmological examination should be standard of care in all orbital fracture patients. An ideal reconstructed orbital floor fracture should accelerate the restoration of orbital function with acceptable cosmetic results. Management parameters of orbital fractures such as timing of surgery, incision type, and implant materials, though widely discussed, remain controversial. In this study, 55 patients with orbital floor fractures surgically reconstructed with conchal cartilage grafts between 2008 and 2014 were retrospectively evaluated. Complications and long-time follow-up visit results have been reported with clinical and radiographic findings. The aim of this study was to present the authors' clinical experiences of reconstruction of blow-out fractures with auricular conchal graft and to evaluate the other materials available for use.

Lower Eyelid Retraction Repair with Resorbable Polydioxanone Implants

PURPOSE:

To report a unique technique to repair lower eyelid retraction using resorbable polydioxanone implants.

PATIENTS AND METHODS:

This was a retrospective, consecutive, nonrandomized interventional case series. Patients with lower eyelid retraction after trauma repaired facial fracture, thyroid eye disease, lower eyelid blepharoplasty, and long-standing facial palsy were treated with middle lamellar spacer using absorbable polydioxanone implant. All patients were recruited from the King Abdulaziz University Hospital, Riyadh, Saudi Arabia. Only patients with minimum follow-up of 12 months were included in the study.

RESULTS:

Eight patients (4 males and 4 females) underwent lower eyelid retraction repair using absorbable polydioxanone implant. The mean age was 43 years (range, 23–63 years). All patients noted improved ocular surface symptoms. The improvement in eyelid retraction ranged from 1.5 to 4 mm with an average of 2.7 mm postoperatively. The implant was well tolerated with no major complications.

CONCLUSIONS:

Several options for spacer materials are available. Absorbable polydioxanone implants seem to be an effective middle lamellar spacer that is a good alternative for repairing middle lamella related lower eyelid retraction and lower eyelid support.

Use of bioresorbable implants for orbital fracture reconstruction

PURPOSE

Bioresorbable implants offer several advantages over permanent implants and serve as a useful alternative in the reconstruction of orbital fractures. Our aim of the study was to evaluate the clinical effectiveness and safety of various bioresorbable implants in the repair of orbital fractures.

METHODS

A retrospective review of all patients who had undergone orbital fracture repair with bioresorbable implants in a single tertiary trauma centre from January 2005 to December 2014 was performed. Main outcome measures included improvement in ocular motility, diplopia, enophthalmos and infraorbital hypoaesthesia, as well as complication rates.

RESULTS

Our study comprised 94 patients and 98 orbits. The types of fractures included orbital floor blow-out fractures (56.1%), zygomaticomaxillary complex fractures (20.4%), combined orbital floor and medial wall fractures (15.3%) and medial wall blow-out fractures (5.1%). The implants evaluated included poly-L/DL-lactide implants (P[L/DL]LA) 85/15 (Rapidsorb), (P[L/DL]LA) 70/30 (PolyMax), polycaprolactone (Osteomesh) and (P[L/DL]LA) 70/30 (MacroPore). There was significant improvement in ocular motility, diplopia, enophthalmos and infraorbital hypoaesthesia postoperatively at week 1, 1 month and 6 months (p<0.001). Comparison of results between the various implants and types of fractures showed no significant difference in postoperative outcome and complications. Late postoperative imaging at 15-24 months showed complete resorption of implants and features of neobone formation in all patients.

CONCLUSION

Our experience with bioresorbable implants shows them to be safe and clinically effective in the reconstruction of orbital fractures.

Orbital floor fractures--short- and intermediate-term complications depending on treatment procedures

Background

Many reconstruction materials for orbital floor fractures have been described in the past including autologous bone transplants, resorbable polymers and titan meshes. So far evidence is missing which material is used successfully regarding indication and particular size of defect. Therefore the aim of this study was to evaluate which reconstruction technique produces best clinical outcome and least complications associated with indication.

Methods

Retrospectively, surgical and ophthalmological data plus CT scans from a collective of 775 patients between 2005 and 2012 were analyzed. Furthermore included patients were sounded on satisfaction and potential problems postoperatively.

Results

Overall 593 patients offered full pre- and postoperative short-time data appropriate to inclusion criteria – of these 507 (85,5 %) underwent primary surgical treatment. Smallest average defect size was found in cases with no indication for surgical treatment (81 mm²), largest in cases indicating titanium mesh reconstruction (601.5 mm²). In 15 cases exact fragment reposition was possible without insertion of alloplastic material. Best clinical results obtained reconstruction using polydioxanone foil (PDS). 0.15 mm PDS-foil: 444 patients, reduced diplopia pre to postoperative 16 to 6 % (p < 0.01), ex- and enophthalmus < 2 % after surgery. 0.25 mm PDS-foil: 26 patients, reduced diplopia from pre- to postoperative 34,6 to 3,8 % (p < 0.01), postoperative exophthalmus rate was higher than preoperative (3,8 to 7,7 %). In comparison to reconstruction with PDS-foil a higher percentage of patients reconstructed with titanium meshes (n = 22) revealed no significant reduction of diplopia (45,5 to 31,8 %; p = 0.07). Furthermore 63 of all included patients agreed to complete a questionnaire on intermediate-term postoperative symptoms and surgical contentedness. Remarkably 50 % of the patients reconstructed with titanium meshes indicated foreign body sensations and cold feeling in the long-term.

Conclusions

Short- and intermediate-term results of clinical outcome in our patients with surgical treated orbital floor fractures (i.e. diplopia, en- or exophthalmus) reveal that thin resorbable foils, particularly 0.15 mm diameter PDS-foil seem to generate best results referring to orbital floor defects with a size of 250 to 300 mm².

Trial registration

Study number 4222, year 2013, ethics committee of the medical faculty of the Heinrich Heine university of Duesseldorf.

Reconstruction of Orbital Floor Fractures with Porous Polyethylene Implants: A Prospective Study

PURPOSE

The main aim of our study was to assess and evaluate the efficacy, long standing outcome and infection of porous polyethylene implants in treatment of orbital floor fractures.

PATIENT AND METHODS

Twelve patients with fractures of orbital floor were included in the study. The cause of fracture was road traffic accident, self fall and cow hit respectively. They also complained of enophthalmos (n = 9), diplopia (n = 3), restricted eye movement (n = 2), impairment of infraorbital nerve (n = 3) and dystopia (n = 6). All the fractures were reconstructed with thin porous polyethylene sheets.

RESULTS

No implants were extruded and there were no signs of inflammatory reactions against porous polyethylene implant. In all nine patients with pre-op enophthalmos it was corrected post-operatively with p value = 0.000 and was statistically significant; diplopia in one patient was corrected; persistence of double vision was noted in two patients. Restricted eye movement was corrected in all patients, dystopia was corrected in four patients and in two patients have persisting dystopia. Paresthesia persisted in all three patients.

CONCLUSION

Our experience was that reconstruction of orbital floor fracture using porous polyethylene implant is reliable, safe and effective and may be used for reconstruction of the orbital floor fracture with no donor site morbidity.

Components of the plasminogen activation system promote engraftment of porous polyethylene biomaterial via common and distinct effects

Rapid fibrovascularization is a prerequisite for successful biomaterial engraftment. In addition to their well-known roles in fibrinolysis, urokinase-type plasminogen activator (uPA) and tissue plasminogen activator (tPA) or their inhibitor plasminogen activator inhibitor-1 (PAI-1) have recently been implicated as individual mediators in non-fibrinolytic processes, including cell adhesion, migration, and proliferation. Since these events are critical for fibrovascularization of biomaterial, we hypothesized that the components of the plasminogen activation system contribute to biomaterial engraftment. Employing in vivo and ex vivo microscopy techniques, vessel and collagen network formation within porous polyethylene (PPE) implants engrafted into dorsal skinfold chambers were found to be significantly impaired in uPA-, tPA-, or PAI-1-deficient mice. Consequently, the force required for mechanical disintegration of the implants out of the host tissue was significantly lower in the mutant mice than in wild-type controls. Conversely, surface coating with recombinant uPA, tPA, non-catalytic uPA, or PAI-1, but not with non-catalytic tPA, accelerated implant vascularization in wild-type mice. Thus, uPA, tPA, and PAI-1 contribute to the fibrovascularization of PPE implants through common and distinct effects. As clinical perspective, surface coating with recombinant uPA, tPA, or PAI-1 might provide a novel strategy for accelerating the vascularization of this biomaterial.