Extradural resection of the anterior clinoid process: How I do it (original) (raw)
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Anterior clinoidectomy using an extradural and intradural 2-step hybrid technique
Journal of neurosurgery, 2018
Anterior clinoidectomy is a difficult yet essential technique in skull base surgery. Two main techniques (extradural and intradural) with multiple modifications have been proposed to increase efficiency and avoid complications. In this study, the authors sought to develop a hybrid technique based on localization of the optic strut (OS) to combine the advantages and avoid the disadvantages of both techniques. Ten cadaveric specimens were prepared for surgical simulation. After a standard pterional craniotomy, the anterior clinoid process (ACP) was resected in 2 steps. The segment anterior to the OS was resected extradurally, while the segment posterior to the OS was resected intradurally. The proposed technique was performed in 6 clinical cases to evaluate its safety and efficiency. Anterior clinoidectomy was successfully performed in all cadaveric specimens and all 6 patients by using the proposed technique. The extradural phase enabled early decompression of the optic nerve while a...
Selective extradural anterior clinoidectomy for supra- and parasellar processes
Journal of Neurosurgery, 1997
✓ Removal of the anterior clinoid process (ACP) facilitates radical removal of tumors or radical neck clipping of aneurysms in the supra- and parasellar regions by providing a wide operative exposure of the internal carotid artery (ICA) and the optic nerve and by reducing the need for brain retraction. Over a period of 3 years, anterior clinoidectomy was performed in 40 patients, 30 of whom harbored aneurysms (18 of the ICA and 13 of the basilar artery [one patient had two aneurysms]) and 10 of whom had tumors (four large pituitary tumors, four craniopharyngiomas, and two sphenoid ridge meningiomas). The ACP was removed extradurally in 31 cases and intradurally in nine cases. Extradural clinoidectomy was performed in all cases of pituitary adenoma and craniopharyngioma and in most cases of basilar artery aneurysm. Intradural clinoidectomy was performed in two cases of ICA—ophthalmic artery aneurysm, two cases of ICA—posterior communicating artery aneurysm, two cases of ICA cavernous...
Extradural anterior clinoidectomy: Technical nuances from a learner′s perspective
Asian Journal of Neurosurgery, 2014
been debated upon. Extradural anterior clinoidectomy is often perceived as difficult and risky due to the constricted working space and the vulnerability of critical anatomical structures encountered, which includes the clinoidal carotid segment, oculomotor nerve and the optic nerve. However, with proper extradural exposure of the ACP and accurate knowledge of the anatomical relationships in this region, extradural anterior clinoidectomy can be safely accomplished. Illustrating through cadaveric prosection, we intend to describe in this paper the proper technique for extradural clinoidectomy, emphasizing the key steps for optimum exposure and safe removal of the anterior clinoid.
Morphometry of Anterior Clinoid Process: A Cadaveric Study
International Journal of Anatomy and Research, 2016
Surgeries in the paraclinoid region for the clinoid segment of internal carotid artery, periclinoid tumours, lesions of anterior part of cavernous sinus and traumatic optic neuropathy require the removal of anterior clinoid process to increase the accessibility to the important structures in the region. Anterior clinoidectomy is a critical and important procedure and requires utmost knowledge of the morphometry of anterior clinoid process. So, this study was undertaken to record the morphometry of anterior clinoid process (ACP). Materials and Methods: Fifty formalin-fixed cadavers were utilized from a medical college in Mumbai, Maharashtra. The measurements were done bilaterally after removal of the brain and meticulous dissection of cranial fossae was done to reflect the duramater, nerves, vessels and other structures from the field of measurement. Results: The mean distance between the tip of ACP and medial margin of the optic canal on the right side was 11.5 mm and on the left side was 11.6 mm; the mean distance between the tip of ACP and lateral margin of the optic canal on the right side was 5.4 mm and on the left side was 5.4 mm; the mean distance between medial margin of the optic canal and the lateral edge of ACP on the right side was 14.3 mm and on the left side was 14.2 mm; the mean distance between the lateral margin of the optic canal and the lateral edge of ACP on the right side was 3.3 mm and on the left side was 3.4 mm; the mean distance between the tip of ACP and the tip of posterior clinoid process (PCP) on the right side was 4.2 mm and on the left side was 4.3 mm; the mean distance between the tips of ACP was 22.8 mm; the mean distance between the ACPs at the level of lateral margin of the optic canal was 23.9 mm; the mean distance between the ACPs at the level of medial margin of the optic canal was 12.3 mm and mean vertical dimension of the ACP at the level of lateral margin of optic canal was 2.4 mm. Conclusion: The findings of the present study will help the surgeons in surgeries of the cavernous sinus and paraclinoid region requiring anterior clinoidectomy.
Operative Neurosurgery, 2015
BACKGROUND: Drilling of the anterior clinoid process (ACP) is an integral component of surgical approaches for central and paracentral skull base lesions. The technique to drill ACP has evolved from pure intradural to extradural and combined techniques. OBJECTIVE: To describe the computerized morphometric evaluation of exposure of optic nerve and internal carotid artery with proposed tailored intradural (IDAC) and complete extradural (EDAC) anterior clinoidectomy. METHODS: We describe a morphometric subdivision of ACP into 4 quadrangles and 1 triangle on the basis of fixed bony landmarks. Computerized volumetric analysis with 3dimensional laser scanning of dry-drilled bones for respective tailored IDAC and EDAC was performed. Both approaches were compared for the area and length of the optic nerve and internal carotid artery. Five cadaver heads were dissected on alternate sides with intradural and extradural techniques to evaluate exposure, surgical freedom, and angulation of approach. RESULTS: Complete anterior clinoidectomy provides a 2.5-times larger area and 2.7times larger volume of ACP. Complete clinoidectomy deroofed the optic nerve to an equal extent as by proposed the partial tailored clinoidectomy approach. Tailored IDAC exposes only the distal dural ring, whereas complete EDAC exposes both the proximal and distal dural rings with complete exposure of the carotid cave. CONCLUSION: Quantitative comparative evaluation provides details of exposure and surgical ease with both techniques. We promote hybrid/EDAC technique for vascular pathologies because of better anatomic orientation. Extradural clinoidectomy is the preferred technique for midline cranial neoplasia. An awareness of different variations of clinoidectomy can prevent dependency on any particular approach and facilitate flexibility.
Endoscopic extradural anterior clinoidectomy and optic nerve decompression through a pterional port
Journal of Clinical Neuroscience, 2014
Since the first description of the intradural removal of the anterior clinoid process, numerous refinements and modifications have been proposed to simplify and enhance the safety of the technique. The growing use of endoscopes in endonasal and transcranial approaches has changed the traditional management of many skull base lesions. We describe an endoscopic extradural anterior clinoidectomy and optic nerve decompression through a minimally invasive pterional port. Minimally invasive optic nerve decompression, with endoscopic extradural anterior clinoidectomy, through a pterional keyhole craniotomy was performed on five preserved cadaveric heads. The endoscopic pterional port provided a shorter and more direct route to the anterior clinoid region, and helped avoid unnecessary and extensive bone removal. An extradural approach helped minimize complications associated with infraction of the subdural space and allowed for the maintenance of visibility while drilling with continuous irrigation. Adequate 270°bone decompression of the optic canal was achieved in all specimens. Endoscopic extradural anterior clinoidectomy and optic nerve decompression is feasible through a single minimally invasive pterional port.
Neurosurgery, 2015
Drilling of the anterior clinoid process (ACP) is an integral component of surgical approaches for central and paracentral skull base lesions. The technique to drill ACP has evolved from pure intradural to extradural and combined techniques. To describe the computerized morphometric evaluation of exposure of optic nerve and internal carotid artery with proposed tailored intradural (IDAC) and complete extradural (EDAC) anterior clinoidectomy. We describe a morphometric subdivision of ACP into 4 quadrangles and 1 triangle on the basis of fixed bony landmarks. Computerized volumetric analysis with 3-dimensional laser scanning of dry-drilled bones for respective tailored IDAC and EDAC was performed. Both approaches were compared for the area and length of the optic nerve and internal carotid artery. Five cadaver heads were dissected on alternate sides with intradural and extradural techniques to evaluate exposure, surgical freedom, and angulation of approach. Complete anterior clinoidec...
Anterior Clinoidectomy: Intradural Step-by-Step En Bloc Removal Technique
World Neurosurgery, 2021
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World neurosurgery, 2017
Surgical management of lesions located in the upper clival region remains challenging. Indeed, complex open transcranial approaches have been used to reach surgical targets in these areas. From all of them, the fronto-temporo-zygomatic (FTOZ) approach combined with an intradural posterior clinoidectomy has been recently proposed as the most reliable route to manage such lesions. The aim of our study is to investigate the possibility to combine a minimally invasive endoscopic endonasal extradural posterior clinoidectomy (EPC) with a standard frontolateral approach in order to expand the working area within the upper clival region. Investigators dissected ten human cadaveric heads at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona (Spain). The heads were positioned to simulate a supine position, thus enabling the simultaneous use of both endonasal and frontolateral routes. The dissections were divided in three steps: 1) standard frontolateral approach; 2) EPC; 3...
Neurosurgery Quarterly, 2011
This study was undertaken to determine the morphometry of the anterior clinoid process (ACP), optic strut (OS), caroticoclinoid foramen, and interclinoid osseous bridge in skulls of Turkish adults. Measurements were taken from 34 dry skulls of unknown age and sex. The overall means, and associated standard deviations, of the distances measured are: basal width of the ACP at the medial margin of the optic canal (OC) 12.4 ± 2.1 mm; from the anterior clinoid tip (ACT) to the base of the ACP 11.5 ± 1.9 mm; from the ACT to the posterior margin of the OS 6.9 ± 1.6 mm; thickness of the ACP 4.3 ± 1.2 mm; from the ACT to the junction of the medial edge of the ACP and the posterolateral edge of the OC roof 8.9 ± 1.6 mm; from the ACT to the center point of the posterior edge of the OC roof 11.4 ± 1.7 mm; from the ACT to the lateral end of the superior orbital fissure 23.7 ± 3.9 mm; from the ACT to the anterior edge of the OS base 8.6 ± 1.7 mm; from the ACT to the posterior edge of the OS base 6.5 ± 1.5 mm; from the ACT to the posterior clinoid process 10.6 ± 2.4 mm; between the ACTs 25.8 ± 2.7 mm. In addition, the presence of a caroticoclinoid process and interclinoid bridge was identified and the types were classified. Knowledge of the morphometry of the parasellar and suprasellar regions is extremely important for neurosurgeons.