The linear and angular dimensions of the L4-L5 facet in healthy  adults: Measurements on the axial and parasagittal-oblique mri planes

Bozkurt Gulek¹*, Behice Durgun², Nazan Alparslan³, Eren Erken⁴, Huseyin Ozer⁴, Tunay Sarpel⁵

¹Adana Numune Teaching and Research Hospital, Department of Radiology.

²Cukurova University School of Medicine, Department of Anatomy.

³Cukurova University School of Medicine, Department of Biostatistics.

⁴Cukurova University School of Medicine, Department of Rheumatology and Immunology.

⁵Cukurova University School of Medicine, Department of Physical Therapy and Rehabilitation.

*Corresponding author E-mail: bozkurtgulek@yahoo.com; Phone: +90 322 355 0101

Accepted 03 April, 2013

Abstract

An understanding of the L4/L5 facet morphology should help in the design of  facet instrumentation and decrease the risk of surgical complications. Despite the use of the axial plane, there are no reported normal values of the facet dimensions using the parasagittal-oblique plane on magnetic resonance imaging (MRI).   The aim of this study was to document the L4/L5 facet joint dimensions in terms of angles and linear distances in healthy subjects using MRI, and to explore both the correlation between the morphological characteristics of the L4-L5 facet joint, and the association  between these characteristics and the parameters of gender, height, and weight, of the subjects. 123 volunteers (51 males and 72 females) participated  in this investigative study. The facet heights and widths were measured on the parasagittal-oblique MRI plane. Since the axial plane clearly depicted the facet joint, this plane was used for the mesurements of the sagittal and transverse facet angles. Intraobserver reliability was found to be high (intraclass correlation coefficient being 99.5 %). The male linear and angular parameters were larger than the female ones. There were significant differences between males and females in terms of the lengths and widths of the L4 facets (p < 0.01 and p < 0.03, respectively). No associations were found between the facet dimensions and the parameters of height and weight. This study provides baseline information about the morphological characteristics of the L4/L5 facet joint, which may well contribute to the success of related surgical interventions and also make possible the accurate simulation of this component of the segment of motion.

Keywords: Lumbar spine, facet joint, facet angle, MRI, functional spinal unit (motion segment)