Anatomy of Lamina of Subaxial Spine Based on Computerized Tomographic Measurement
Jittipong Sanpote MD*, Thanwa Sudsang MD**, Kriangsak Saetia MD*
Affiliation : * Division of Neurosurgery, Department of Surgery, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand ** Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Background : Translaminar screw fixation of C2 has been widely used because of the safety and the ease of surgical technique.
However, there were only few reports regarding anatomy of subaxial cervical spine for translaminar screw fixation.
Objective : To collect the database of morphometric parameters of lamina of subaxial cervical spines and determine the
feasibility of translaminar screw fixation at subaxial cervical spines.
Material and Method: The authors analyzed CT scans of cervical spines of 100 patients at Ramathibodi Hospital between
June and December 2016. Morphometric study of each lamina from C3 to C7 was done. The feasibility of translaminar screw
placement was determined and analyzed.
Results : There were 61 male and 39 female patients. The largest laminar thickness was at C7 while the smallest was at C5.
C7 translaminar screw placement provided a high success rate of 97% and 89% by unilateral and bilateral screw placement,
respectively. C3 and C6 had a moderate chance of success but relatively poor chance of success at C4 and C5. There were no
statistical differences between genders, left and right side in terms of morphometric parameters, and feasibility of screw
placement.
Conclusion : C7 translaminar screw placement offers an alternative method of posterior fixation in subaxial cervical spine.
There are variations in thickness of lamina of C3 and lamina of C6, therefore, a CT scan of cervical spine is recommended
before the attempt of screw placement. C4 and C5 translaminar screw should be avoided due to the small diameter of lamina.
Keywords : Translaminar screw, Cervical spine, Cervical fixation, Anatomy
