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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 19  |  Issue : 3  |  Page : 146-152

Orbital floor reconstruction using prebent titanium mesh or polyetheretherketone patient-specific implant: Comparative study


Department of Oral & Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta, Egypt

Date of Submission15-May-2022
Date of Decision19-Jun-2022
Date of Acceptance20-Jun-2022
Date of Web Publication14-Sep-2022

Correspondence Address:
Maram N Breshah
PhD, Department of Oral & Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tdj.tdj_14_22

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  Abstract 


Purpose
This study was planned to compare between polyetheretherketone patient-specific implant and prebent titanium mesh in orbital floor reconstruction.
Patients and methods
Twelve patients with unilateral orbital floor fracture indicated for reconstruction divided in two equal groups according to the type of implant used. Postoperative evaluation was done for 6 months. Patients of both groups were examined clinically for hypoglobus, enophthalmos, ocular motility and diplopia and radiographically for orbital volume measurement preoperatively and postoperatively. A comparative analysis of the treatment outcomes was performed.
Results
Significant improvement in the external appearance of the eye including hypoglobus, enophthalmos, and ocular motility and diplopia although group II showed one (16.7%) patient with persistent hypoglobus, one (16.7%) patient measured as grade 3 enophthalmos (>2 mm), one (16.7%) patient with marked limitation of ocular motility (grade 3) and diplopia. There was significant improvement in the orbital volume of the affected side in both groups with no significant difference postoperatively between both groups during different follow up periods. There was significant difference between the orbital volume of the affected and nonaffected sides preoperatively and the difference between them was 3.91 ± 0.92 cm3 for group I and 3.64 ± 1.29 cm3 for group II which markedly decreased postoperatively was 0.50 ± 0.72 cm3 for group I and 1.35 ± 0.86 cm3 for group II with no significant difference between affected and nonaffected eyes.
Conclusion
The results of this study showed that polyetheretherketone patient-specific implant is precise, predictable, and demonstrated higher clinical efficacy in comparison to prebent titanium mesh in orbital floor reconstruction. Preformed prebent titanium mesh is not preferred in large defects.

Keywords: orbital reconstruction, polyetheretherketone, patient-specific implant, titanium mesh


How to cite this article:
Beder RR, Breshah MN, Ibrahim MT. Orbital floor reconstruction using prebent titanium mesh or polyetheretherketone patient-specific implant: Comparative study. Tanta Dent J 2022;19:146-52

How to cite this URL:
Beder RR, Breshah MN, Ibrahim MT. Orbital floor reconstruction using prebent titanium mesh or polyetheretherketone patient-specific implant: Comparative study. Tanta Dent J [serial online] 2022 [cited 2022 Dec 1];19:146-52. Available from: http://www.tmj.eg.net/text.asp?2022/19/3/146/356080




  Introduction Top


Traumatic defects of the orbit continue to be a great challenge in maxillofacial surgery due to the intricacy of these injuries, the varying trauma patterns, and the need for an interdisciplinary approach which is usually coupled with aesthetic and functional abnormalities [1].

Traditional procedures for orbital reconstruction often entail the use of standard titanium meshes, plates or polymeric implants [2].

Standard titanium meshes require preoperative or intraoperative bending and correction of their contours, and despite of these adaptations, the proper installation and positioning of the implants within the orbit and their conformance to the individual anatomy of the damaged structures which is considered critical for the overall success rate in orbital reconstruction are still difficult to achieve due to loss of anatomical landmarks and changes in topography of the orbit [3],[4],[5],[6],[7].

The employment of mirror-imaging techniques with the assistance of three-dimensional computed tomographic (3DCT) scanning and 3D printing for reconstruction of orbital fractures might enhance the outcome and optimize the functional and esthetic restoration of traumatic orbital fractures [8],[9].

Salmi et al. [10] reported that 3D printing biomodels are not exact reproductions of natural anatomy and that the dimensional error for their construction ranges from 0.18 to 0.55%, however, this dimensional disparity is minimal and precise adaptation to fractured margins is possible preoperatively. Mispositioning seen with intraoperative imaging usually arises from an inadequately adapted implant or poor surgical technique and hence justifies its utilization.

Recent advances in CAD/CAM technology have demonstrated its efficacy in management of facial bone defects, which has piqued the interest of many surgeons involved in orbital reconstruction who demonstrated the successful application of patient-specific implants (PSI) for orbital reconstructions [1],[5],[6],[7],[11].

Although much research addresses the issues of cranioplasty and frontal bone reconstructions with polyetheretherketone (PEEK) implants, only few papers report the outcomes of the orbital wall reconstructions with PEEK PSI [12],[13]. The aim of this study was to compare between PEEK PSIs and prebent titanium mesh in patients with unilateral orbital floor defects.


  Patients and methods Top


A total of 12 patients with unilateral orbital floor fracture indicated for reconstruction were selected as proven by diplopia within 30°, enophthalmos of more than 2 mm and radiological evidence of extraocular muscle entrapment. After written informed consent from the patient, orbital wall reconstruction was performed with prebent titanium orbital meshes or PEEK custom manufactured orbital implants.

The patient's age ranged from 14 to 55 years old, 10 of them were males and two were females. All patients were divided in two equal groups according to the implant type (PEEK PSI/prebent titanium mesh) used for orbital floor reconstruction. Group I included six patients, who had undergone orbital reconstruction procedures with PSI made of PEEK. Group II included six patients who had been treated with prebent orbital titanium mesh.

Patients of both groups were examined clinically preoperatively and postoperatively for hypoglobus, enophthalmos, and ocular motility and diplopia [Figure 1] and [Figure 2], also examined radiographically by multiaxial CT scan of the face preoperatively for proper diagnosis and treatment planning [Figure 3] and postoperatively after 2 weeks, 1, 3, and 6 months. CT was used for measuring the orbital volume by an automated method using BONELOGIC CMF ORBITAL version 2.1.18-research software for 3D analysis provided by Disior Oy.
Figure 1: Preoperative clinical photograph of case no. 2 group I showing hypoglobus of right eye with limitation of ocular motility in upward and upward lateral gaze.

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Figure 2: Preoperative clinical photograph of case no. 4 group II showing hypoglobus of left eye with limitation of ocular motility in upward and upward medial gaze.

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Figure 3: (a, b) Preoperative coronal, sagittal views of computed tomography radiographs showing right orbital floor fracture with soft tissue herniation into maxillary sinus. (c, d) Preoperative coronal, sagittal views of computed tomography radiographs showing left orbito zygomaticomaxillary fracture with orbital floor fracture.

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3D simulation with mirroring techniques and rapid prototyping orbital modeling was performed for all cases using (3Diagnosys, version 4.1; 3diemme, Como, Italy). 3D printer (Upbox, Tiertime, Korea) was used to print the patient-specific model using the technology of fused deposition modeling.

PSI design was carried out in close collaboration between surgeons and biomedical engineers. Based on preoperative CT data (DICOM files without compression) biomedical engineers created the design of the implant and defined its optimal position inside the orbit with the participation and under decision of surgeons. The implants were made by milling of PEEK blocks using Mimics 10.01 (Materialise, Leuven, Belgium) [Figure 4].
Figure 4: a) Virtual mode of PEEK PSI positioned into the orbit, (b) intraoperative view of PEEK PSI after reduction and fixation, (c) patient-specific printed model onto which a titanium mesh is well adapted, (d) intraoperative view of preadapted titanium mesh and orbital rim plate as part of reduction and fixation of orbito zygomaticomaxillary fracture. PEEK, polyetheretherketone; PSI, patient-specific implant.

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All implants were sterilized preoperatively with standard surgical protocol in both groups. Surgical approach either infraorbital or transconjunctival incision according to the case. Titanium meshes were adapted manually during surgery using individual 3D orbital models until the mesh was fully seated without any rocking [Figure 4].

Statistical analysis was done using Statistical Package for Social Sciences (SPSS) program Version 25, P value was calculated, and data was collected and tabulated.


  Results Top


This study was conducted on twelve patients with unilateral displaced isolated blowout orbital (six patients) or orbitozygomatico maxillary complex fractures (six patients) indicated for orbital floor reconstruction as evidenced clinically and radiographically. The male to female ratio was 5: 1 [10 (83.3%) male and two (16.7%) females]. The most common cause of trauma in this study was road traffic accidents in 58.3% (seven patients) followed by falls in 25% (three patients) followed by assault in 16.7% (two patients).

For clinical evaluation regarding to hypoglobus, in return to the preoperative status at which all patients in each group (100%) showed hypoglobus, postoperatively all six (100%) patients in group I and five (83.3%) patients in group II showed absence of hypoglobus. Only one (16.7%) patient in group II showed persistent hypoglobus [Table 1] [Figure 5] and [Figure 6].
Table 1: Changes in hypoglobus preoperatively and postoperatively in both groups

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Figure 5: First month postoperative clinical photograph of case no. 2 group I showing absence of hypoglobus.

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Figure 6: First month postoperative clinical photograph of case no. 2 group I showing no limitation of ocular motility.

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Regarding to enophthalmos, preoperatively, five (83.3%) patients in each group were measured as grade 3 and one (16.7%) patient in each group was measured as grade 2. Postoperative measurements revealed that all six (100%) patients in group I improved less than or equal to 2 mm in comparison to preoperative measurements while in group II five (83.3%) patients improved less than or equal to 2 mm and one (16.7) patient measured as grade 3 (>2 mm) [Table 2], [Figure 6].
Table 2: Changes in enophthalmos preoperatively and postoperatively in both groups

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For ocular motility the results showed improvement in the limitation of ocular motility of the affected eye in comparison to preoperative status. In group I five (83.3%) patients showed no limitation of ocular motility and one (16.7%) patient showed slight limitation (grade 1). In group II four (66.7%) patients showed no limitation of ocular motility, one (16.7%) patient showed slight limitation (grade 1) and one (16.7%) patient showed marked limitation of ocular motility (grade 3) [Table 3], [Figure 7] and [Figure 8]. For diplopia, three (50%) patients in each group reported diplopia preoperatively which had been resolved postoperatively except one (16.7%) patient in group II reported persistent diplopia.
Table 3: Changes in ocular motility preoperatively and postoperatively

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Figure 7: First month postoperative clinical photograph of case no. 4 group II showing presence of hypoglobus and enophthalmos.

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Figure 8: First month postoperative clinical photograph of case no.4 group II showing limitation of ocular motility in upward gaze.

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In our study there was a significant improvement in the orbital volume of the affected side in both groups as there was significant difference between the orbital volume of the affected and nonaffected sides preoperatively (P = 0.039 for group I and P value 0.047 for group II) and the difference between them was 3.91 ± 0.92 cm3 for group I and 3.64 ± 1.29 cm3 for group II which markedly decreased postoperatively was 0.50 ± 0.72 cm3 for group I and 1.35 ± 0.86 cm3 for group II with no significant difference between affected and nonaffected eyes (P = 0.786 for group I and P = 0.439 for group II). Measurements of orbital volume revealed no significant difference postoperatively between both groups during different follow up periods [Table 4] and [Table 5].
Table 4: Changes in orbital volume in all follow up periods in relation to the preoperative status

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Table 5: Difference in orbital volume between affected and nonaffected eye in both groups

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For radiographic evaluation there was a significant improvement in the orbital volume of the affected side as the difference between the orbital volume of the affected and nonaffected sides preoperatively markedly decreased postoperatively [Figure 9].
Figure 9: (a, b) Sixth month postoperative coronal and sagittal computed tomography radiograph of case no. 2 group I showing accurate orbital floor reconstruction using PEEK PSI without artifact. (c, d, e) Sixth month postoperative coronal and sagittal computed tomography radiograph of case no. 4 group II showing inaccurate orbital floor reconstruction with prebent titanium mesh. PEEK, polyetheretherketone; PSI, patient-specific implant.a

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  Discussion Top


Orbital reconstruction is always a challenge for surgeons due to anatomical complexity, small size, and exceptional importance of the eye for the human life [14] especially for those orbits included in this study with larger or comminuted defects (>50%) as they have significant disruption necessitates intervention with repair because they leave enophthalmos, diplopia or limitation of ocular motility when left unrepaired in accordance to Hammer and Prein [15].

We excluded bilateral orbital fracture cases and included unilateral cases to have a nonpreviously injured intact side as a reference for our study. Also we excluded cases with permanent eye damage such as ruptured globe to avoid non necessary intervention.

The sex distribution showed a clear predominance of males with ratio of male to female of 5: 1 and this in agree with Ji et al. [16] which is due to more physical activity of males.

In our study we used titanium mesh because it showed better results than bone grafts for orbital reconstruction according to Ellis and Tan [17] as it is malleable and adaptable to the shape of the defect, the most biocompatible of all available material, connective tissue can grow around and through the implant and prevent its migration, also according to Goldberg et al. [18] and Kelly et al. [19] who showed that bone grafts were associated with donor site morbidity, variable degree of resorption, prolonged total operating time, postoperative pain, scaring, usually rigid and cannot be bend to match the concave–convex shape of the orbital floor, and provide less drainage from the orbit than with titanium.

In order to avoid the main problem associated with the use of the preformed titanium mesh which is the complex process of their adaptation to the parameters of the damaged orbits which leads to more time consuming and less accuracy according to Totir et al. 5 [2] and Mommaerts et al. [7] and with the evolution of the technology of computer-guided surgery and 3D modeling and the recent advances in CAD/CAM technology and construction of PSI with their successful application for orbital reconstruction according to many authors [1],[7],[11], so, the hypothesis of this study was to compare between the prebent titanium mesh and PSI for orbital floor reconstruction.

We used PEEK for reconstruction of PSI as it is a semicrystalline thermoplastic material with good imaging properties as it is translucent to radiograph and nonmagnetic so they do not create artifacts in CT or MRI and because of its stiffness, light weight, chemical resistance, durability, and modulus of elasticity close to the cortical bone. There were no complications related to the implants such as infections, extrusions, seromas, or allergic reactions. These findings were consistent with those of Gerbino et al. [20] and Jalbert et al. [21].

Our results suggest that PEEK PSIs are more clinically effective than prebent titanium implants in orbital volume reconstruction as the mean difference between the intact/damaged orbital volume is within the range of 0.50 ± 0.72 cm3 for peek PSI and this was in acceptance with Chepurnyi et al. [13] who demonstrated results with 0.74 ± 0.6 cm3 of mean difference between damaged and intact orbit after surgery. Our results revealed that the mean difference between the intact/damaged orbital volume is within the range of 1.35 ± 0.86 cm3 for prebent titanium mesh and this was in acceptance with Zhang et al. [22], Zimmerer et al. [23] and Chepurnyi et al. [13] demonstrated the mean difference between the intact/damaged orbital volume for prebent titanium mesh is within the range of 1.6 ± 2.4 and 1.9 ± 1.4 cm3.

The difference in the measurements of the orbital volume between our study and the previous studies may be attributed to the different software used for orbital volume measurement, the sample size or demographic differences.

In this study, there were no significant differences in ocular motility and diplopia between both groups 6 months after surgery with significant improvement due to adequate subperiosteal dissection of the orbital floor and release of any incarcerated tissues which was confirmed by intraoperative forced duction test. However, the motility disorder was totally absent in five patients and was mild in only one (16.7%) patient after orbital reconstruction with PEEK PSI which correlate with Zieliński et al. [24] who showed the presence of motility disorders after CAD/CAM-assisted orbital reconstructions in 29 and 13% of cases 1 and 6 months after surgery, respectively. The motility disorder was totally absent in four patients and was mild in one patient and marked in another one (33.4%) after reconstruction with prebent orbital mesh. For diplopia, only one (16.7%) patient in group II reported persistent diplopia. This marked motility limitation and persistent diplopia may be due to inaccurate reconstruction or muscle fibrosis.

The results obtained regarding both hypoglobus and enophthalmos postoperatively showed significant resolution after orbital reconstruction with PEEK PSI because of the stiffness in PSIs makes it more stable dimensionally and prevents its deformation during placement, this was in acceptance with Gander et al. [25]. While after reconstruction with prebent titanium mesh one patient showed hypoglobus and enophthalmos which may be due to that the defect was large and the risk of malposition increases significantly with the fracture size and extension, this was in acceptance with Schlittler et al. [26] who mentioned that preformed titanium meshes are often insufficient to completely cover the defect so, they are at risk of implant malposition and also in acceptance with Jalbert et al. [21] who mentioned that large defects exposes mechanical weakness of preformed titanium mesh.


  Conclusion Top


PEEK PSI demonstrated higher clinical efficacy in comparison to prebent titanium mesh in orbital reconstruction especially in restoring the volume and shape and function of the damaged orbit which makes it precise and predictable in the treatment of orbital defects preformed prebent titanium mesh is not preferred in large defects.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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