Reference intervals of C2-C7 lateral spinous process deviation in Chinese adults

Lateral spinous process deviation (LSPD) is a commonly used morphological parameter in the anatomical study of the cervical spinous process. However, quantitative studies on this issue are still lacking. In this study we aimed to establish reference intervals of C2-C7 LSPD in the adult Chinese population and provide decision-making information for clinical practitioners.

This was a retrospective study of 92 adult patients who received neck computed tomography scans, including 42 females and 50 males meeting the inclusion criteria. Three-dimensional reconstruction and anatomical measurements were performed using Mimics Research 19.0 and 3-Matic Research 11.0.

The inter-observer reliability of LSPD measurement in this study was excellent (intraclass correlation coefficient value > 0.93). Only 2 cases of LSPD angles of 90 degrees were found, which means most cervical spinous process exist deviation. The reference interval for the C2-C7 LSPD angle was (85.11, 94.75) degrees. The C2 LSPD showed the different directions to C5 and C7 (p < 0.05). In the C4 vertebrae, the male tends to have greater LSPD angles than the female (T = -2.013, p = 0.047). In the C2 vertebrae, there was a statistically significant but weak correlation between age and LSPD angles (r = 0.24, p = 0.029). There was no statistically significant effect of sex or age on other levels of cervical vertebrae.

Cervical spinous process deviation of less than 5 degrees on either side is a common morphological manifestation in Chinese adults. Thus, LSPD may not be an indicator for clinical care. Moreover, the vertebrae may have opposite directions of LSPD in the upper levels (C2-C4) and lower levels (C5-C7).