gms | German Medical Science

Objective: To analyze surgical exposure to different artificial lesions from frontolateral and pterional and combined frontopterional approach.

Method: Two fixed cadaver heads were injected with silicone. The frontolateral approach followed by the pterional were performed sequentially. The bony flaps were fixed, to reconstruct the frontolateral, the pterional and the combined frontopterional approach. Three colored spheres (diameter 4 mm) were placed around the optic chiasm:

1.

Between the optic nerves over the sellar diaphragm (blue);

2.

Between the right optic nerve and the right internal carotid artery (yellow);

3.

Lateral of the internal carotid artery and medial of the oculomotor nerve on the sphenoid wing (green).

The different approaches were compared with regard to the surgical exposures to these structures (from maximally lateral and medial working angle, respectively).

Results:

4.

Blue sphere: From the frontolateral and the combined frontopterional approach the total area of surgical exposure between the two optic nerves to the sellar diaphragm and to the blue sphere is greater than from the pterional approach because of the straight perspective. Because of the larger vertical angle, it was also possible to reach the blue sphere from the lateral side between the right optic nerve and the internal carotid artery from frontopterional and pterional, but not from frontolateral approach.

5.

Yellow sphere: Frontopterional and pterional approach enable exposure of a larger part of the surface of the yellow sphere than the frontolateral approach.

6.

Green sphere: Frontopterional and pterional approach allow a better exposure of lateral structures such as the oculomotor nerve. In addition, they enable better exposure of the green sphere in comparison with the frontolateral approach.

Conclusions: Because of a greater vertical angle, the pterional approach provides a larger exposure of the area under the optic chiasm from a lateral view than the frontolateral approach, whereas the frontolateral approach is superior for the way between the two optic nerves.