Introduction: Keyhole craniotomies leverage ever smaller cranial openings and advanced optics for intracranial surgeries. When compared to standard craniotomy, key hole approaches may improve cosmesis, decrease hospital stay, operating time and brain and soft tissue trauma. A subset of keyhole surgeries is the pterional keyhole approach, widely used by neurovascular skull base surgeons. A standard skin incision for this approach, however, is still lacking. Our objective from this manuscript is to detail the anatomic landmarks, technique and added value of a novel extended lateral skin incision for pterional keyhole craniotomies.
Methods: Ten fresh cadaveric heads were dissected. The anatomic landmarks were noted especially with respect to the frontal branch of the facial nerve. Four incisions related to the extended lateral approach were sequentially performed with respective calvarial and intracranial structure exposures annotation.
Results: The central incision (incision A) provided a mean calvarial area exposure of approximately 2.55cm2, length 2.5cm by width 1.3cm. Caudal zigzag extension (incision B) provided a total exposure of 4.95cm2, 3.5cm by 1.8cm. Supraorbital extension (Incision C) provided an exposure of 7.07cm2, 4.5cm by 2.0cm. Medial suprabrow extension (incision D) provided an exposure of 7.85cm2, 5.5cm by 2.0cm. Subsequent craniotomy for incision A provided excellent subfrontal exposure, however limited exposure to the temporal side of the sphenoid ridge and the Sylvian fissure. There was limited visualization of the middle cranial fossa, limited maneuverability and limited accessibility. With caudal zigzag extension craniotomy (Incision B), there was better visualization of the temporal side of the sphenoid ridge and as a result improved exposure to the sylvian fissure, anterior and middle cranial fossa and temporal lobe. Maneuverability and accessibility improved remarkably as well. Added value for incision C extension craniotomy was minute, and negligible for incision D.
Conclusions: The extended lateral incision is a versatile and aesthetic incision for the pterional keyhole approach. Anatomically, it is ideally positioned to provide adequate exposure, accessibility and maneuverability especially when handling Sylvian and middle fossa pathologies.
Patient Care: This research establishes a new versatile incision for minimally invasive keyhole surgery while concomitantly improving aesthetic outcomes.
Learning Objectives: Establish the exposure, accessibility and maneuverability of a new aesthetic incision for pterional keyhole craniotomies.