J Cerebrovasc Endovasc Neurosurg.  2013 Sep;15(3):164-170. 10.7461/jcen.2013.15.3.164.

Two Indices Affecting the Directions of the Sylvian Fissure Dissection in Middle Cerebral Artery Bifurcation Aneurysms

• Park HW
• Chung SY
• Park MS
• Kim SM
• Yoon BH
• Kim HK

• KMID: 1491434
• DOI: http://doi.org/10.7461/jcen.2013.15.3.164

Abstract

OBJECTIVE
This study proposes more objective methods for deciding the appropriate direction of the sylvian fissure dissection during surgical clipping in middle cerebral artery (MCA) bifurcation aneurysms.
METHODS
We reviewed data of 36 consecutive patients with MCA bifurcation aneurysms. We measured 2 indices preoperatively on 3-dimensional computed tomography angiography (3D-CTA). Analysis of the calculated data allowed us to select the appropriate direction of sylvian fissure dissection for ease of proximal control of M1. Statistically, Mann-Whitney test was used.
RESULTS
We classified subjects into 2 groups based on the technical level of M1 exposure during surgical clipping. When it was difficult to expose M1, subjects were assigned to Group I, and Group II were subjects in whom M1 exposure was easy. The mean difference between the distances extending from the limbus sphenoidale (LS) line to the internal carotid artery bifurcation and extending from the LS line to the MCA bifurcation was 1.00 +/- 0.42 mm in group I and 4.39 +/- 2.14 mm in group II. The mean M1 angle was 9.36 +/- 3.73degrees in the group I and 34.05 +/- 16.71degrees in the group II (M1 slope gap p < 0.05, M1 angle p < 0.05).
CONCLUSION
We have found an objective method for preoperatively verifying ease of exposure of M1 artery during surgical clipping. Therefore, we suggest use of the preoperative M1 slope gap and M1 angle as indicators in 3D-CTA selecting the direction of sylvian fissure dissection for easy proximal control of M1.

Keyword

Middle cerebral artery; Intracranial aneurysm; Dissecting; Three-dimensional cerebral angiography

MeSH Terms

Aneurysm
Angiography
Arteries
Carotid Artery, Internal
Humans
Intracranial Aneurysm
Middle Cerebral Artery
Surgical Instruments

Figure

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  Fig. 1 The distance extending from the limbus sphenoidale line (LS; dotted line) to the internal carotid artery (ICA) bifurcation (A) and that extending from the limbus sphenoidale line to middle cerebral artery (MCA) bifurcation (B).

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  Fig. 2 M1 angle (Asterisk) between the straight segment of distal M1 at aneurysmal neck (Dotted line) and LS line.

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  Fig. 3 The distance from the LS line to the ICA bifurcation is 2.41 mm (A). The distance from the LS line to the MCA bifurcation is 3.72 mm (B) and the difference between 2 lines is 1.31 mm. The M1 angle is 10.2 (Asterisk).

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  Fig. 4 An intra-operative view of the left MCA bifurcation aneurysm (a), M2 branches (b). It is difficult to identify M1 vessel.

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  Fig. 5 The distance from the LS line to the ICA bifurcation is 8.64 mm (A). The distance from the LS line to the MCA bifurcation is 2.11 mm (B) and the difference between 2 lines is 6.53 mm. The M1 angle is 51.7 (Asterisk).

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  Fig. 6 An intraoperative view of the right MCA bifurcation aneurysm (a), M2 branches (b), M1 (c). It is easy to identify M1 vessel (c).

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