Paratrigeminal, Paraclival, Precavernous, or All of the Above?€¦ · Paratrigeminal, Paraclival,...
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Paratrigeminal, Paraclival, Precavernous, or All of the Above? Circumferential anatomic study of the C3-C4 transitional segment of the internal carotid artery Eleonora Marcati 1 , Sebastien Froelich 4 , Norberto Andaluz 1,3 , James Leach 5 , Lee Zimmer 1-3 , Almaz Kurbanov 1 , Jeffrey Keller 1,3 Departments of 1 Neurosurgery and 2 Otolaryngology Head & Neck Surgery, University of Cincinnati (UC) College of Medicine; 3 Comprehensive Stroke Center at UC Neuroscience Institute, Cincinnati, Ohio; 4 Department of Neurosurgery, Lariboisière Hospital, Paris, France; 5 Department of Radiology and Medical Imaging, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio Background Our cadaveric study used an integrated anatomic approach to reconcile various internal carotid artery (ICA) nomenclature schemas, from both transcranial and endonasal perspectives. Our aims were two fold: 1) describe a distinct precavernous, or C3C4 transitional segment of the ICA and 2) establish a circumferential anatomical correlation of the loosely described paraclival ICA with its surrounding relevant anatomical structures. Results • A meningeal membrane covering the superior border of V2 was consistently identified as the lateral aspect of the cavernous sinus floor. • In 18 (69%) of 26 sides, venous channels were absent on the paratrigeminal quadrilateral area. Area averaged 25.8 ± 9.6 mm 2 and 23.8 ± 9.1 mm 2 by transcranial and endonasal perspectives, respectively. • Medially, the precavernous ICA corresponded with the paraclival ICA. Conclusions CIRCUMFERENTIAL ANATOMIC ANALYSIS: showed the paraclival ICA represents the medial aspect of the precavernous, or C34 transitional segment of the ICA. It is not a distinct segment by itself. NEW C3C4 TRANSITIONAL ICA SEGMENT: our revised classic antegrade ICA classification introduces this new transitional segment. It corresponds to the paratrigeminal ICA (seen transcranially and endonasally) whereas the paraclival ICA is seen only endonasally. Materials & Methods In 13 adult cadaveric formalinfixed heads injected with colored silicone, bilateral transcranial extradural and endonasal endoscopic CTguided dissections were performed. Transcranial: defined a quadrilateral area medial to Meckel’s cave (MC) between CN VI, antero and posterolateral borders of the ICA, and posterior longitudinal ligament (PLL). Endoscopic: exposed the area through the “door” between MC and ICA using an angled 45 degree endoscope. Measurements: made in situ for both approaches. Anatomical correlations were made using 6μm coronal histological sections of the sellar region and neuroradiological images. Figure 1. Anatomic dissections. A: Transcranial exposure of the precavernous ICA and surrounding structures. B: Membrane limiting the lateral aspect of the floor of the cavernous sinus (CS). C: 3D schema of paratrigeminal border of the precavernous ICA. Figure 2. Endoscopic views. AC: Endoscopic exposure of the precavernous ICA and surrounding structures. D: MRI, CT, MRA, CTA coronal representation of ICA segments. E: 3D view of C1C7 segments. F: Histological coronal section of the precavernous ICA.
Transcript of Paratrigeminal, Paraclival, Precavernous, or All of the Above?€¦ · Paratrigeminal, Paraclival,...
Paratrigeminal, Paraclival, Precavernous, or All of the Above? Circumferential anatomic study of the C3-C4 transitional segment of the internal carotid artery
Eleonora Marcati1, Sebastien Froelich4, Norberto Andaluz1,3, James Leach5, Lee Zimmer1-3, Almaz Kurbanov1, Jeffrey Keller1,3
Departments of 1Neurosurgery and 2Otolaryngology Head & Neck Surgery, University of Cincinnati (UC) College of Medicine; 3Comprehensive Stroke Center at UC Neuroscience Institute, Cincinnati, Ohio; 4Department of Neurosurgery, Lariboisière Hospital, Paris, France; 5Department of Radiology and Medical Imaging, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
Background Our cadaveric study used an integrated anatomic approach to reconcile various internal carotid artery (ICA) nomenclature schemas, from both transcranial and endonasal perspectives. Our aims were two-fold: 1) describe a distinct precavernous, or C3-C4 transitional segment of the ICA and 2) establish a circumferential anatomical correlation of the loosely described paraclival ICA with its surrounding relevant anatomical structures.
Results• A meningeal membrane covering the superior border of V2 was consistently identified as the lateral aspect of the cavernous sinus floor.
• In 18 (69%) of 26 sides, venous channels were absent on the paratrigeminal quadrilateral area. Area averaged 25.8 ± 9.6mm2 and 23.8 ± 9.1 mm2 by transcranial and endonasal perspectives, respectively.
• Medially, the precavernous ICA corresponded with the paraclival ICA.
ConclusionsCIRCUMFERENTIAL ANATOMIC ANALYSIS: showed the paraclival ICA represents the medial aspect of the precavernous, or C3-4 transitional segment of the ICA. It is not a distinct segment by itself. NEW C3-C4 TRANSITIONAL ICA SEGMENT: our revised classic antegrade ICA classification introduces this new transitional segment. It corresponds to the paratrigeminal ICA (seen transcranially and endonasally) whereas the paraclival ICA is seen only endonasally.
Materials & Methods In 13 adult cadaveric formalin-fixed heads injected with colored silicone, bilateral transcranial extradural and endonasal endoscopic CT-guided dissections were performed. Transcranial: defined a quadrilateral area medial to Meckel’s cave (MC) between CN VI, antero- and posterolateral borders of the ICA, and posterior longitudinal ligament (PLL). Endoscopic: exposed the area through the “door” between MC and ICA using an angled 45- degree endoscope. Measurements: made in situ for both approaches. Anatomical correlations were made using 6-μm coronal histological sections of the sellar region and neuroradiological images.
Figure 1. Anatomic dissections. A: Transcranial exposure of the precavernous ICA and surrounding structures. B: Membrane limiting the lateral aspect of the floor of the cavernous sinus (CS). C: 3D schema of paratrigeminal border of the precavernous ICA.
Figure 2. Endoscopic views. A-C: Endoscopic exposure of the precavernous ICA and surrounding structures. D: MRI, CT, MRA, CTA coronal representation of ICA segments. E: 3D view of C1-C7 segments. F: Histological coronal section of the precavernous ICA.
