The Eyebrow versus the Eyelid Approach for Supraorbital Craniotomy: Anatomical and Surgical Considerations

Aim: To compare the eyebrow and eyelid approaches for supraorbital craniotomy with regard to anatomical exposure und surgical indications.

Methods: We performed an anatomical study on 6 cadavers and 4 skulls. The measurements were recorded with photo and video documentation. Neuroendoscopy was used to enhance the visualization of deep-seated structures. A CT scan with 3D reconstruction was performed to measure and compare the working angles of the two approaches.

Results: For the eyebrow approach, we made a 3cm skin incision (traveling laterally from the supraorbital notch to the lateral end of the eyebrow). For the eyelid approach, we made a 4cm skin incision (a curvilinear incision along the supratarsal fold with a short lateral extension). With the eyebrow incision, the skin can be retracted 2.5cm upward from the lower edge of the orbital rim, whereas it can be retracted 1.5cm with the eyelid incision. To achieve an equal craniotomy size of 2.5x1.5cm, the orbital rim has to be removed with the eyelid approach, but this is not necessary with the eyebrow approach. With the eyebrow approach, a craniotomy measuring 2.5x2cm can be achieved if the orbital rim is removed. With the eyelid approach, the craniotomy measures 2.5x1.0cm if the orbital rim is not removed. The craniotomy obtainable by a “standard” eyebrow approach (without orbital osteotomy)(1) is located 1 cm farther superior to that obtainable by a “standard” eyelid approach (with orbital osteotomy)(2). This yields a craniocaudal working angle of 15.7° (with the skull base as reference and the anterior clinoid process as target) for the eyebrow approach, and 10° for the eyelid approach.

Conclusions: The supraorbital craniotomy through an eyebrow approach yields a more superiorly located bony opening than an equal sized craniotomy through an eyelid approach. As a result, the eyebrow approach gives a larger craniocaudal working angle, which will provide better access to aneurysms of the anterior circulation and skull base lesions. For larger frontal lesions, an orbital osteotomy can be performed in addition to extend upward access. The eyelid approach gives a flatter working angle which may limit dissection of the basal cisterns. It is most useful for high-riding aneurysms of the anterior communicating artery, suprasellar lesions and orbital roof lesions. The eyelid approach remains an acceptable alternative in case of sparse eyebrow growth that would make an eyebrow incision cosmetically unacceptable.