ABSTRACT
Introduction: There are various diseases and anomalies in humans which require occipitocervical fusion using medial orlateral occipital screw placement along with rod or plate placement.[1] There are many ongoing arguments regarding the safearea for screw placement on the occiput during fusion techniques. Morphological analysis of occipital bone thickness providesconfidence in placing screws. Here, we try mapping occipital bone using computed tomography (CT) which would benefit forsafe fusion in population of southern Tamil Nadu.Materials and Methods: We randomly selected the CT scans of 50 patients in the age group of 20–60 years, and occipitalbone thickness mapping is done and tabulated and compared with the previous studies from different demographical areas.Results: The maximum thickness of the occipital bone was at the level of the external occipital protuberance (EOP) at 16.2 mm.Areas with thicknesses >8 mm were more frequent at the EOP and up to 2 cm in all directions, as well as up to 1 cm in alldirections at a height of 1 cm inferiorly, and up to 3 cm from the EOP inferiorly in males and it’s up to 2 cm in females. Themale group tended to have a thicker occipital bone than the female group, and the differences were significant around the EOP.Based on these data, there are 10 safe points for males which include: M0, M1, M2, M3, L1, L2, R1, R2 at level 0, L1, and R2at level 1 and 9 safe points for female which include all the above except M3.Conclusion: There is variability in the thickness of occipital bone in adult people from different demographic areas andthere is also a significant difference between male and female patients. Hence, this study helps in pre-operative planning inoccipitocervical fusion in people of this region.
ABSTRACT
Aim: The aim of the study is to analyze the usefulness of lamina terminalis fenestration (LTF) in hydrocephalus secondary tosubarachnoid hemorrhage while performing surgical interventions for anterior circulation aneurysm and to know the limitationsof this procedure in patients who undergo clipping of these aneurysms.Materials and Methods: A total of 81 aneurysms in 78 patients were included in this study from the year 2001 to 2018. Patientsin the age range of 12–80 years were included. Male-female ratio was 1:1.1. Until February 2011, LTF was done for 9 patientswho had any degree of hydrocephalus as an adjuvant to clipping of the anterior circulation aneurysms. After March 2011, insteadof LTF, intraoperative ventricular tapping was done in patients with hydrocephalus.Results: Among the 9 cases who had undergone LTF, two patients developed frontoparietal subdural hygromas with masseffect. From March 2011 till date after stopping LTF, only 2 of 47 patients required ventriculoperitoneal shunt who ultimatelydeveloped chronic hydrocephalus.Conclusion: LTF can lead to potential complications such as subdural hygromas due to poor absorption in blood cloggedsubarachnoid spaces. This procedure must be adopted with caution as it has its own limitations.