Orbital floor Reconstruction with Custom Made plates - A New Approach

Reconstruction of the orbital floor can present a challenge in both trauma and ablative surgery for malignancies. According to the available literature, orbital floor fractures represent 67% to 84% of all cases of orbital fractures. There are a wide ranges of autogenous and alloplastic materials used when reconstructing the defective orbit. The use of a physical 3D model of the patient has been a great advantage in planning and infomed patient consent prior to surgical reconstruction. 3D CT reconstruction scans are used in producing the 3D model. However because of the minimal thickness of the orbital floor and medial wall and the variability in orbital soft tissue displacement, the resulting model can often be a poor reproduction of the remaining structures.. We describe an improved technique in producing accurate orbital floor reproduction for custom made plates.

 We are presenting 3 cases, 2 traumatic orbital floor defects and 1 case of post ablative surgery medial orbital wall defect reconstruction. All the patients had 3D reconstruction CT scans; this was converted to plane Dicom data. MIMICS (V.12, Materialise, Belgium) software was used to convert the file and identify and threshold the various tissues. The volume of air in the maxillary and ethmoid air sinus of the normal side was isolated from the threshold images. This was cropped form the images, converted into a CAD file STL (standard triangulation language) and then superimposed on to the injured side. When correctly aligned the final bone and air images were combined and saved. The merged repaired model and the original defect 3D models were printed (ZCorp 310 Plus Printer,USA) and compared for accuracy. This repaired model is waxed up to fill minor flaws and then 0.3mm swaged titanium plate (Titanium International, Birmingham, UK) fabricated to the casts. These plates were sterilised and used to reconstruct the orbital floor defects.

 All three patients had their orbital floor reconstructed using the fabricated custom made titanium plates had good aesthetic and functional outcome.  

Reconstruction of the orbital walls in trauma and ablative surgery can be challenging. The accurate reconstruction is vital in producing good functional results. The advantages of 3D models has been widely reported, in our unit they provide advantages in terms of planning, consent and production (3).. This new technique has negated the problems created by low orbital wall thickness and variable soft tissue replication of the orbits. The laboratory technique is readily available and easy to replicate. This can reduce the post operative morbidity; reduce the cost and operative time.

 1. The Custom-made titanium orbital floor prosthesis in reconstruction for orbital floor fractures. Br J Oral maxillofacial Surg 2003; 41, 50-53

2. Development of in-house rapid manufacturing of three-dimensional models in maxillofacial surgery. Wesam Aleid , Jason Watson, Andrew J. Sidebottom, Philip Hollows

Br J Oral Maxillofacial Surg 2010; 48, 479–481