Skull Base 2007; 17 - A073
DOI: 10.1055/s-2007-981778

Quantification of the Frontotemporal Orbitozygomatic (FTOZ) Approach Using a Three-Dimensional Visualization and Modeling Application

Anthony L D'Ambrosio 1(presenter), J. Mocco 1, Todd C Hankinson 1, Harry R van Loveren 1, Jeffrey N Bruce 1
  • 1Tampa and New York, USA

Objectives: To simulate the frontotemporal orbitozygomatic (FTOZ) craniotomy in a three-dimensional (3D) virtual environment on patient-specific data. To quantify the exposure afforded by the FTOZ while simulating controlled amounts of brain retraction.

Methods: Four computed tomography angiograms were reconstructed using commercial software (Amira 4.1.1) and virtual FTOZ craniotomies were performed bilaterally (n = 8). Brain retraction was simulated at 1 and 2 cm. “Surgical freedom” and “projection angle” were measured at each stage of the FTOZ and compared.

Results: At 1 cm of retraction, surgical freedom increased by 27 ± 14% for the frontotemporal orbital (FTO) and by 31 ± 18% for the FTOZ (p < 0.01) when compared to the frontotemporal (FT) craniotomy. At 2 cm of retraction, surgical freedom increased by 15 ± 5% and 26 ± 8% for the FTO and FTOZ, respectively (p < 0.01). With increased retraction, surgical freedom increased by 100 ± 26%, 81 ± 15%, and 82 ± 27% for the FT, FTO, and FTOZ craniotomy, respectively (p < 0.001). Projection angle increased by 24.2% when orbital rim removal was added to the FT craniotomy (p < 0.01).

Conclusions: Surgical freedom increases significantly at every step of the FTOZ craniotomy. This effect is less robust when brain retraction is increased. Brain retraction has a greater impact on surgical freedom than bone removal alone. Projection angle is significantly increased when orbital rim removal is added to the FT craniotomy. This model overcomes two major limitations of cadaver-based models: quantification of brain retraction and incorporation of patient-specific anatomy.