Morphometric analysis of cervical interlaminar space for posterior surgical approach and decompression

The purpose of this study is to provide a morphometric description of the bony margins of the interlaminar spaces by level in the cervical spine for guidance of safe posterior cervical surgical dissection and decompression. We also aim to describe the impact of increasing static cervical lordosis on the overlap between the lamina.

Morphometric measurements of the interlaminar space were performed on 100 consecutive cervical spine CT scans of patients ranging in age from 18 to 50 years were selected. Three raters performed measurements of the interlaminar height measured using two techniques (true interlaminar height and surgical interlaminar height), and interlaminar width from C2-C3 to C7-T1.

In total, 100 patients were included. The true interlaminar height was greatest at C2-3, C3-4, C4-5 (5.2 ± 1.4-1.8 mm) and smallest at C6-7 (4.4 ± 1.3 mm). Surgical interlaminar height was greatest at C3-4 (4.2 ± 1.7) and smallest at C6-7 (3.0 ± 1.3 mm). The widest interlaminar space was observed at C3-4 (27.1 ± 2.1 mm) and most narrow at C7-T1 (20.9 ± 2.4 mm). Following multivariate regression, male gender was associated with greater interlaminar widths at each cervical level between C4 and T1 (Table 2). While greater patient height was associated with larger interlaminar height (true and surgical) and width at C2-3 and C4-5, weight was not independently associated with the interlaminar measurements. Increasing C2-C7 lordosis was significantly associated with decreasing true and surgical interlaminar heights at all levels except C7-T1, but was not associated with differences between interlaminar width.

The study provides a morphometric analysis of interlaminar anatomy in the cervical spine. Surgeons can apply this information in their pre-operative plan to safely approach the posterior cervical spine.