Gender and Population Variation in Craniometry and Freehand Pass Ventriculostomy Nawaporn Techataweewan 1 , Beatrix Dudzik 2 , Amnat Kitkhuandee 3 , Pichayen Duangthongphon 3 , Nancy Tayles 4 - BACKGROUND: Ventriculostomy using the freehand pass method is subject to complications arising from misplacement of the catheter tip. This method may require multiple passes for successful catheterization. Methods of determining the burr-hole location (known as the Kocher point) were derived historically from European patients and may not be appropriate for other populations with different cranial shapes. This study examines the possibility that anatomic variation in interpopulation variation together with sexual dimorphism in cranial size and shape may contribute to this problem. - METHODS: Sagittal and parasagittal measurements of the frontal bone were taken of 300 Thai (150 female, 150 male) crania and 300 American white (150 female, 150 male) crania. These measurements were compared to determine sexual dimorphism and interpopulation variation in size and shape. - RESULTS: The measurements were statistically signifi- cantly larger in males than in females and on the right side than the left in both sexes in both Thai and American white samples. The frontal bone is significantly longer at the sagittal plane in Europeans of both sexes than in Thai, but in the parasagittal plane, there is no difference. This finding indicates a difference in frontal bone shape be- tween the 2 populations and between males and females. - CONCLUSIONS: The dimensions of the frontal bone vary between males and females and can vary among pop- ulations. The optimal location for the burr hole in freehand pass ventriculostomy may depend on both the gender and the ancestry of the patient. INTRODUCTION V entriculostomy, the insertion of an intraventricular cath- eter into one of the ventricles of the brain for diagnostic or therapeutic purposes, is one of the most commonly per- formed procedures in neurosurgery. 1-3 It requires drilling a burr hole in the cranium, most often in the frontal bone, to allow insertion of the catheter and may be used to acquire diagnostic samples of cerebrospinal fluid (CSF), as a means of temporary external ventricular drainage to reduce intracranial pressure 4 or to enable the insertion of a permanent shunt. 5,6 As a life-saving procedure, it is often practiced in emergencies using the free- hand pass technique, with surface anatomic landmarks being used to locate the burr hole and guide the angle of insertion of the catheter. 3,7 The optimal location for the catheter tip for sampling CSF or draining a lateral ventricle is a precise point inside the frontal horn, just anterior to the foramen of Monro. 8,9 This point is not affected by changes in the shape or size of the ventricle after surgery and avoids the choroid plexus so is the location at which the catheter can operate most efficiently. 10 Given the frequency of the need for ventriculostomy, a range of technical means of locating and guiding the angle of insertion of the catheter have been developed. These means include a relatively simple device to guide the angle of insertion, 11-13 endoscopy, 14 stereotactic neuronavigation, 15,16 ultrasonography, 16 and more recently, the Ventriguide 17 and a simple device using magnetic Key words - Cranial sexual dimorphism - Cranial shape - Craniometric genetic variation - External ventricular drain Abbreviations and Acronyms CS: Coronal suture CSF: Cerebrospinal fluid CT : Computed tomography KKU: Khon Kaen University MRI: Magnetic resonance imaging SD: Standard deviation SOR: Midsupraorbital rim From the 1 Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; 2 Department of Anatomy, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, Tennessee, USA; 3 Department of Surgery, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; and 4 Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand To whom correspondence should be addressed: Nawaporn Techataweewan, M.D., Ph.D. [E-mail: nawtec@kku.ac.th] Citation: World Neurosurg. (2018). https://doi.org/10.1016/j.wneu.2018.05.240 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2018 Elsevier Inc. All rights reserved. WORLD NEUROSURGERY -: e1-e10, - 2018 www.WORLDNEUROSURGERY.org e1 Original Article