### Abstract

Object. This study was designed to determine if the "keyhole concept," proposed by Perneczky's group, can be verified quantitatively. Methods. Fourteen (3 bilateral and 8 unilateral) sides of embalmed latex-injected cadaveric heads were dissected via 3 sequential craniotomy approaches: supraorbital keyhole, frontotemporal pterional, and supraorbital. Threedimensional cartesian coordinates were recorded using a stereotactic localizer. The orthocenter of the ipsilateral anterior clinoid process, the posterior clinoid process, and the contralateral anterior clinoid process are expressed as a center point (the apex). Seven vectors project from the apex to their corresponding target points in a radiating manner on the parasellar skull base. Each 2 neighboring vectors border what could be considered a triangle, and the total area of the 7 triangles sharing the same apex was geometrically expressed as the area of exposure in the parasellar region. Results. Values are expressed as the mean SD (mm2). The total area of exposure was as follows: supraorbital keyhole 1733.1 336.0, pterional 1699.3 361.9, and supraorbital 1691.4 342.4. The area of exposure on the contralateral side was as follows: supraorbital keyhole 602.2 194.7, pterional 595.2 228.0, and supraorbital 553.3 227.2. The supraorbital keyhole skull flap was 2.0 cm2, and the skull flap size ratio was 1:5:6.5 (supraorbital keyhole/ pterional/supraorbital). Conclusions. The area of exposure of the parasellar region through the smaller supraorbital keyhole approach is as adequate as the larger pterional and supraorbital approaches. The keyhole concept can be verified quantitatively as follows: 1) a wide area of exposure on the skull base can be obtained through a small keyhole skull opening, and 2) the side opposite the opening can also be visualized.

Original language | English (US) |
---|---|

Pages (from-to) | 264-269 |

Number of pages | 6 |

Journal | Journal of Neurosurgery |

Volume | 118 |

Issue number | 2 |

DOIs | |

State | Published - Feb 2013 |

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### Keywords

- Diagnostic and operative techniques
- Keyhole approach
- Pterional approach
- Supraorbital approach

### ASJC Scopus subject areas

- Clinical Neurology
- Surgery

### Cite this

*Journal of Neurosurgery*,

*118*(2), 264-269. https://doi.org/10.3171/2012.9.JNS09186

**Quantitative verification of the keyhole concept : A comparison of area of exposure in the parasellar region via supraorbital keyhole, frontotemporal pterional, and supraorbital approaches ; Laboratory investigation.** / Cheng, Cheng Mao; Noguchi, Akio; Dogan, Aclan; Anderson, Gregory; Hsu, Frank P K; Mcmenomey, Sean O.; Delashaw, Johnny B.

Research output: Contribution to journal › Article

*Journal of Neurosurgery*, vol. 118, no. 2, pp. 264-269. https://doi.org/10.3171/2012.9.JNS09186

}

TY - JOUR

T1 - Quantitative verification of the keyhole concept

T2 - A comparison of area of exposure in the parasellar region via supraorbital keyhole, frontotemporal pterional, and supraorbital approaches ; Laboratory investigation

AU - Cheng, Cheng Mao

AU - Noguchi, Akio

AU - Dogan, Aclan

AU - Anderson, Gregory

AU - Hsu, Frank P K

AU - Mcmenomey, Sean O.

AU - Delashaw, Johnny B.

PY - 2013/2

Y1 - 2013/2

N2 - Object. This study was designed to determine if the "keyhole concept," proposed by Perneczky's group, can be verified quantitatively. Methods. Fourteen (3 bilateral and 8 unilateral) sides of embalmed latex-injected cadaveric heads were dissected via 3 sequential craniotomy approaches: supraorbital keyhole, frontotemporal pterional, and supraorbital. Threedimensional cartesian coordinates were recorded using a stereotactic localizer. The orthocenter of the ipsilateral anterior clinoid process, the posterior clinoid process, and the contralateral anterior clinoid process are expressed as a center point (the apex). Seven vectors project from the apex to their corresponding target points in a radiating manner on the parasellar skull base. Each 2 neighboring vectors border what could be considered a triangle, and the total area of the 7 triangles sharing the same apex was geometrically expressed as the area of exposure in the parasellar region. Results. Values are expressed as the mean SD (mm2). The total area of exposure was as follows: supraorbital keyhole 1733.1 336.0, pterional 1699.3 361.9, and supraorbital 1691.4 342.4. The area of exposure on the contralateral side was as follows: supraorbital keyhole 602.2 194.7, pterional 595.2 228.0, and supraorbital 553.3 227.2. The supraorbital keyhole skull flap was 2.0 cm2, and the skull flap size ratio was 1:5:6.5 (supraorbital keyhole/ pterional/supraorbital). Conclusions. The area of exposure of the parasellar region through the smaller supraorbital keyhole approach is as adequate as the larger pterional and supraorbital approaches. The keyhole concept can be verified quantitatively as follows: 1) a wide area of exposure on the skull base can be obtained through a small keyhole skull opening, and 2) the side opposite the opening can also be visualized.

AB - Object. This study was designed to determine if the "keyhole concept," proposed by Perneczky's group, can be verified quantitatively. Methods. Fourteen (3 bilateral and 8 unilateral) sides of embalmed latex-injected cadaveric heads were dissected via 3 sequential craniotomy approaches: supraorbital keyhole, frontotemporal pterional, and supraorbital. Threedimensional cartesian coordinates were recorded using a stereotactic localizer. The orthocenter of the ipsilateral anterior clinoid process, the posterior clinoid process, and the contralateral anterior clinoid process are expressed as a center point (the apex). Seven vectors project from the apex to their corresponding target points in a radiating manner on the parasellar skull base. Each 2 neighboring vectors border what could be considered a triangle, and the total area of the 7 triangles sharing the same apex was geometrically expressed as the area of exposure in the parasellar region. Results. Values are expressed as the mean SD (mm2). The total area of exposure was as follows: supraorbital keyhole 1733.1 336.0, pterional 1699.3 361.9, and supraorbital 1691.4 342.4. The area of exposure on the contralateral side was as follows: supraorbital keyhole 602.2 194.7, pterional 595.2 228.0, and supraorbital 553.3 227.2. The supraorbital keyhole skull flap was 2.0 cm2, and the skull flap size ratio was 1:5:6.5 (supraorbital keyhole/ pterional/supraorbital). Conclusions. The area of exposure of the parasellar region through the smaller supraorbital keyhole approach is as adequate as the larger pterional and supraorbital approaches. The keyhole concept can be verified quantitatively as follows: 1) a wide area of exposure on the skull base can be obtained through a small keyhole skull opening, and 2) the side opposite the opening can also be visualized.

KW - Diagnostic and operative techniques

KW - Keyhole approach

KW - Pterional approach

KW - Supraorbital approach

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UR - http://www.scopus.com/inward/citedby.url?scp=84873633034&partnerID=8YFLogxK

U2 - 10.3171/2012.9.JNS09186

DO - 10.3171/2012.9.JNS09186

M3 - Article

C2 - 23140145

AN - SCOPUS:84873633034

VL - 118

SP - 264

EP - 269

JO - Journal of Neurosurgery

JF - Journal of Neurosurgery

SN - 0022-3085

IS - 2

ER -