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Updated: Jun 3, 2026
Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms
Published on: August 11, 2015
The impact of minimizing brain retraction in aneurysm surgery: evaluation using magnetic resonance imaging
Niklaus Krayenbühl1, Minna Oinas, Eren Erdem
1Department of Neurosurgery, University Hospital Zürich, Zürich, Switzerland. nkrayenbuehl@bluewin.ch
Background:
Recent advances in skull base and microsurgical techniques minimize the need for brain retraction.
Objective:
We studied the impact of such techniques in 36 patients (51 aneurysms) using magnetic resonance imaging (MRI).
Methods:
Preoperative and 24 hours postoperative MR imaging was performed in patients undergoing microsurgical clipping of intracranial aneurysms. Images were evaluated for parenchymal signal changes. During surgery, use and time of brain retraction were recorded. The degree of cortical injury was quantified using a 0 to 3 scale (grade 0 = normal surface; 1 = pial/arachnoidal damage; 2 = gray matter injury; 3 = contusion/necrosis).
Results:
Brain retraction by use of a brain spatula was used in all patients. Retraction times ranged from 14 to 290 minutes (mean, 84.1). Cortical surface changes were grade 0 in 86% and grade 1 in 14%; none showed grade 2 or 3 changes. In the postoperative MRI, 4 patients presented with parenchymal alterations, 4 with edema (11.1%), and 1 patient had additional contusion (2.8%). All lesions were confined to the temporal pole. The grade of cortical surface changes was not related to lesions found on MR imaging. No patients showed retraction-related neurological deficits.
Conclusion:
The incidence of evident mechanical parenchymal injury (infarction or contusion) is very low when appropriate microsurgical and skull base techniques are used. Minor pia-arachnoid injury should nevertheless continue to be attended through future advances.
Insights
Advanced skull base surgery significantly reduces brain injury. Microsurgical techniques for aneurysm clipping resulted in minimal cortical damage and low incidence of parenchymal injury, ensuring patient safety.
Area of Science:
- Neurosurgery
- Microsurgery
- Skull Base Surgery
Background:
- Recent advancements in skull base and microsurgical techniques aim to reduce the necessity of brain retraction during intracranial procedures.
- Minimizing brain retraction is crucial for preventing neurological deficits and improving patient outcomes.
Purpose of the Study:
- To evaluate the impact of modern skull base and microsurgical techniques on brain injury.
- To assess parenchymal changes using magnetic resonance imaging (MRI) after microsurgical clipping of intracranial aneurysms.
Main Methods:
- Prospective study involving 36 patients with 51 intracranial aneurysms.
- Preoperative and postoperative MRI scans were utilized to detect parenchymal signal alterations.
- Cortical injury was graded intraoperatively (0-3 scale), and brain retraction duration was recorded.
Main Results:
- Brain retraction was employed in all cases, with mean retraction time of 84.1 minutes.
- 86% of patients showed no cortical surface changes (grade 0), and 14% had minor pial/arachnoidal damage (grade 1).
- Postoperative MRI revealed minimal parenchymal alterations, including edema in 11.1% and contusion in 2.8%, predominantly at the temporal pole. No retraction-related neurological deficits were observed.
Conclusions:
- The use of appropriate microsurgical and skull base techniques leads to a very low incidence of evident mechanical parenchymal injury.
- While significant injury is rare, minor pia-arachnoid damage warrants continued attention and refinement of surgical approaches.
