High-Resolution CT Modeling for Facial Reconstruction Surgery

Such implants appear to provide excellent aesthetic results and are well tolerated over the long term, according to new research.

Severe facial and eye cavity abnormalities may be present at birth or can occur following facial trauma or another medical procedure, such as the removal of a tumor, according to the investigators. Surgery to correct such defects aims to restore anatomic integrity, to increase the function of the eyelids and face, and to improve a patient's appearance by inserting an implant made either of the individual's own bone and tissue or synthetic materials.

Characteristically, use of these implants, which are shaped during surgery, has failed to recreate ideal three-dimensional (3D) contours in the face. Designing synthetic implants beforehand may improve precision and contours, but concerns have been raised about the long-term implant stability and risk of infection associated with plastics and other non-organic materials.

Michael J. Groth, M.D., and colleagues from the Jules Stein Eye Institute (Los Angeles, CA, USA) evaluated long-term outcomes following the use of acrylic implants in nine patients with complex facial and eye cavity defects caused by facial trauma. The five men and four women were between the ages of 28 and 63 years, with an average age of 48.7. Between one month and 40 years had elapsed since their facial injuries, which included a boating accident, motor vehicle crashes, falls, and a snowboarding accident. All patients had previously undergone reconstructive procedures.

For the current study, which was published in the November/December 2006 issue of the journal Archives of Facial Plastic Surgery, the patients underwent 3D high-resolution CT scanning of the face and head. This information was used to create a stone mold, from which a customized implant made of polymethyl methacrylate (PMMA, also known as acrylic) was cast. The implant was surgically placed and fixed using screws.

During an average of 4.3 years of follow-up, none of the patients experienced significant complications, such as infection, extrusion (forcing out), or displacement of the implant. "In all of the patients, wound healing was uneventful, with antibiotics given perioperatively,” the authors wrote in their article. "All of the patients demonstrated long-term sustained improvement of facial deformities, including facial symmetry and eyelid function. Many types of implant materials have been used for reconstructive orbitofacial surgery. Autogenous [from the patient's body] materials such as bone grafts provide many advantages, including excellent biocompatibility and low infection and extrusion rates. However, these materials have pertinent limitations, such as the potential for a prolonged operative procedure, limited supply, significant resorption, donor site morbidity, and minimal malleability and customization.”

Surgeons have been using compounds such as PMMA to make implants for more than 45 years, and creating them beforehand provides even more advantages, including precision and improved function, according to the researchers.



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