Supramastoid crest, safety landmark for craniotomy?

Area of Science:

• Neurosurgery
• Anatomy
• Surgical Landmarks

Background:

• Bony landmarks are crucial for surgical navigation and reducing complications.
• Limited studies exist on the temporooccipital region's bony anatomy for safe craniotomy.

Purpose of the Study:

• To evaluate the supramastoid crest as a bony landmark.
• To determine its relationship with the transverse and sigmoid sinuses and Labbe's vein.

Main Methods:

• Study conducted on 20 fresh cadaveric heads (40 sides).
• Vessels injected with colored silicone for visualization.
• Measurements taken using a digital caliper to assess distances from the supramastoid crest to nearby venous structures.

Main Results:

• Supramastoid crest identified in 100% of cadavers.
• Craniotomy along the crest proved 100% safe from venous sinus injury.
• Anterior border of the crest aligns with the middle cranial fossa floor in 85-90% of cases.
• Average distance from supramastoid point to transverse sinus: 12.94 mm (right), 11.87 mm (left).
• Average distance from supramastoid point to Labbe's vein: 17.23 mm (both sides).

Conclusions:

• The supramastoid crest is an easily identifiable bony landmark in adult cadavers.
• Craniotomy along this crest ensures safety from injuring venous sinuses and Labbe's vein.
• The anterior border of the supramastoid crest consistently relates to the middle cranial fossa floor.