Orbital Floor Blowout Fracture Reconstruction Using Moldable Polymethyl Methacrylate: A Report of Two Cases and Their Imaging Findings

Abstract

Background: Blowout fracture is defined as an internal orbital fracture that does not involve the orbital rim. This type of fracture results in the loss of tissue and disruption of the structure of the orbital wall. The symptoms and signs include pain, enophthalmos, diplopia, orbital emphysema, and ecchymosis. The surgeon's main goal is to reconstruct the orbit in the best possible manner to achieve optimal anatomy and functionality of the orbit wall postoperatively. There is no consensus regarding the best material for use in surgical orbital reconstruction, despite the commercial availability of several biological and manufactured materials. Moreover, material selection is often based on the practitioner's preferences/experience and patient safety. This study reported two cases of orbital fracture reconstruction using moldable methyl polymethacrylate as a bone surrogate. This material has already been used in dentistry, neurosurgery, and orthopedic surgery and is potentially hazard-free for orbit surgery.

Case presentation: Two victims of motor vehicle collisions presented with blowout orbital fractures. Cross-sectional imaging revealed inferior fractures involving the orbital wall. High-resolution tomographic modeling was used to plan surgical orbital floor reconstruction using moldable polymethyl methacrylate material. The short-term outcome of the implant appeared favorable at the one-year follow-up, based on regular patient monitoring and cross-sectional imaging assessment. Postoperative improvement with positive clinical outcomes was observed during both patients' follow-up visits.

Conclusion: Moldable polymethyl methacrylate can be used safely and effectively for reconstructive surgeries for the management of blowout orbital fractures. This new technique ensured a satisfactory short-term postoperative orbital configuration and tolerance and good esthetic and functional results without adverse effects. This customizable product is affordable and easy to fabricate.

Keywords: computed tomography; implant; magnetic resonance imaging; oculoplasty; trauma.

Conflict of interest statement

The authors declare that they have no conflicts of interest.

© 2022 AlSubaie et al.

Figures

Figure 1

Preoperative coronal (A) and sagittal (B) computed tomography of the head with the bone algorithm showing a comminuted blowout fracture involving the right orbital floor that approximately measures 0.86 cm × 1.5 cm × 1 cm in maximum orthogonal dimensions, which was associated with fat herniation, inferior rectus muscle entrapment, soft tissue swelling, and intra-orbital gas locules The optic nerve appears unaffected.

Figure 2

Steps for intraoperative custom preparation of polymethyl methacrylate implants. (A) Mixing the PMMA acrylic resin powder with the liquid component (from the set) in a sterile ampoule in a well-ventilated atmosphere. (B) Open the peelable pouch and start emptying the whole contents. (C) Enclose into the sterile foil pouch, ie, plastic sleeves. (D) transfer the plastic sleeves to the sterile surgical area, and when the dough-like material does not adhere to the surgical gloves of the surgeon, the PMMA resin is ready for manipulation. Apply the resin to the osseous defect and remove any excess resin.

Figure 3

Postoperative follow-up magnetic resonance imaging of the globes. Multi-sequential coronal planar images of the orbit, including plain T1 weighted imaging (A, B); T1-weighted imaging with contrast and fat saturation (C); and T2-weighted imaging (D). These images demonstrate the status after right orbital floor oculoplasty and inferior orbital wall PMMA implant placement (*) with interval complete sealing of the prior fracture. The placed implant measures 1.69 cm × 1.9 cm (A and B) and can be seen covering nearly the entire inferior orbital wall [2.8 cm] (A). The implant is seen subjacent to the inferior rectus muscle with satisfactory attachment to the right inferior orbital wall and adequate fat spacing from extraocular muscles. No significant asymmetry is observed in orbital muscles bilaterally, nor are there signs of an inflammatory process.

Figure 4

Postoperative photographs in the primary gaze (A) and supraduction (B) positions showing significant correction of the inferior sulcus after the BOF and resolving enophthalmos. The patient was followed up for one year and showed no complications.

Figure 5

Preoperative sagittal (A) and coronal (B) computed tomography of the head with the bone algorithm show a displaced fracture of the left lamina papyracea, medial orbit, and displaced BOF of the left inferior orbital wall, which approximately measures 1.4 cm × 2 cm × 1 cm in its maximum orthogonal dimensions. The BOF is associated with a small, displaced bone fragment, abnormal superior orientation of the globe, orbital fat herniation, tethered inferior rectus muscle (*), and proptosis of the eye.

Figure 6

Postoperative follow-up images of the globes, as multi-sequential MR coronal planar images of the orbit including T1 weighted images without (A and B) and T1 weighted images with contrast and fat saturation (C), and T2 weighted images (D) Coronal CT with the bone algorithm (E) showing the status after left orbital floor cranioplasty and inferior orbital wall implant placement for a previous inferior orbital wall displaced fracture, none of which were visualized on follow-up images. The implant measured 2.2 cm × 1.4 cm and covered nearly the entire inferior orbital wall (2.8 cm). The implant is seen subjacent to the inferior rectus muscle with satisfactory attachment to the left inferior orbital wall and adequate fat spacing from extraocular muscles. No significant asymmetry was observed in the orbital muscles bilaterally, nor are there signs of an inflammatory process or implant sliding.

Figure 7

Postoperative photographs in the primary gaze (A) and supraduction (B) positions showing significant correction of the inferior sulcus after the BOF and resolving enophthalmos The patient was followed up for one year and showed no complications.