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Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms
Published on: August 11, 2015
Bony tunnel formation in the middle meningeal groove: an anatomic study for safer pterional craniotomy
S Shimizu1, H Hagiwara, S Utsuki
1Department of Neurosurgery, Yokohama Stroke and Brain Center, Kanagawa, Japan. Satoru4756@aol.com
Objective:
When the bone flap is removed in a pterional craniotomy, the middle meningeal artery (MMA) should be gently dissected to minimize blood loss. However, when the MMA pierces a bony tunnel in the middle meningeal groove it is easily damaged upon bone flap elevation. We have performed an anatomic study of this tunnel to render pterional craniotomy safer.
Methods:
We examined 78 sides from 39 adult skulls for the presence and length of the tunnel, the distance between the lateral border of the superior orbital fissure and the proximal part of the tunnel, and examined the relationship between the MMA piercing the tunnel to a surface landmark, i.e., the junction of the sphenoparietal, sphenosquamosal, and squamosal sutures.
Results:
We found 59 tunnels on 78 sides (75.6%); 2 were at the branching of the MMA on one side. The tunnels were located on the temporal side of the lesser wing of the sphenoid bone. The length of the tunnel and the distance from the superior orbital fissure were 3-23 mm (mean: 12.2 mm) and 11-33 mm (mean: 18.9 mm), respectively. Most tunnels (86.4%) were bilateral; in 67.8% of the specimens the MMA piercing the tunnel was just beneath the surface landmark.
Conclusion:
As we found a high incidence of bony tunnel formation in the middle meningeal groove, actual findings can be different from the accepted nomenclature. If a tunnel exists, the MMA is easily damaged upon cracking of the lesser wing during bone flap elevation. Recognition of this anatomy may render pterional craniotomy safer.
Insights
A high incidence of bony tunnels in the middle meningeal groove (75.6%) was found, increasing the risk of middle meningeal artery damage during pterional craniotomy. Recognizing this anatomy can improve surgical safety.
Area of Science:
- Neurosurgery
- Anatomy
- Surgical Technique
Background:
- The middle meningeal artery (MMA) is vulnerable to damage during pterional craniotomy, particularly when it traverses a bony tunnel.
- This anatomical variation can lead to significant blood loss and complications.
Purpose of the Study:
- To investigate the anatomical characteristics of the bony tunnel associated with the MMA in the middle meningeal groove.
- To provide data that can enhance the safety of pterional craniotomy procedures.
Main Methods:
- Anatomical examination of 78 sides from 39 adult skulls.
- Assessment of tunnel presence, length, and proximity to the superior orbital fissure.
- Correlation of MMA tunnel location with surface landmarks.
Main Results:
- Bony tunnels were identified in 75.6% of the examined sides.
- Tunnels ranged from 3-23 mm in length, located on the temporal side of the sphenoid bone's lesser wing.
- In 67.8% of cases, the MMA passed beneath a surface landmark at the junction of key cranial sutures.
Conclusions:
- The high prevalence of MMA bony tunnels necessitates awareness among neurosurgeons.
- Understanding this anatomy is crucial for preventing iatrogenic injury to the MMA during pterional craniotomy.
- Recognition of these tunnels can significantly improve surgical outcomes and patient safety.
