Author(s): Adrian B. Catbagan, M.D, Glenn Marc G. Ignacio M.D, Byron C. Gaffud M.D.a and Imarzen V. Elepano, M.D
Studies have shown that Asian cervical pedicles are significantly smaller, thus increasing the technical difficulty of screw insertion when using standard 3.5 mm pedicle screws. Cervical pedicle morphology of a sample of Filipino patients was assessed using computed tomographic measurements.
The study was carried out to measure the cervical pedicles and assess the feasibility of transpedicular screw fixation in the local setting.
CT scans of bilateral C2 to C7 pedicles of 94 Filipinos with a mean age 52.9 years old (range: 18 to 82) composed of 37 females and 57 males were evaluated for inner diameter, lateral wall, and medial wall thickness.
The inner diameter of male pedicles was significantly wider compared to females. The medial wall and lateral wall thickness of males was also significantly greater except for C2-C5 and C2 & C6 respectively. C3 to C5 of male pedicles had a mean inner diameter of < 3.1 mm compared to C2 to C6 in females. For mean lateral wall thickness, only the right C4 and C5 lateral wall thickness in females was< 1.0 mm. All cervical spine levels in both males and females had a mean medial wall thickness of > 1.0 mm (range 1.47 to 1.89mm).
The cervical pedicles of Filipinos are smaller than those reported in Euro-American populations and may be too small to adequately accommodate transpedicular screw fixation using 3.5 mm screws. It is recommended that pre-operative imaging for all levels should be performed when transpedicular screw insertion is indicated.
Key words: cervical spine, morphometry, transpedicular fixation, computed tomography