Details of fibroligamentous structures in the cervical unco-vertebral region: an obscure corner

Abstract

Vertebral bone, joints and ligaments on the cervical spine are structures that maintain the stability of the spine and protect the neurovascular structures. Determining the detailed anatomical location of the intervertebral foramen and unco-vertebral (UV) region with respect to the vertebral bone, joint and ligaments is critical when choosing the safest surgical approach to the cervical spine. We studied the microscopic detailed anatomy of the dural covering and posterior longitudinal ligament (PLL) in eight cadaver specimens and the relevance of these structures in the UV region from C4 to C7. The uncinate process (UP) and its covering ligaments are mechanical barriers that prevent the nerve root and the vertebral artery against unintentional surgical damage. Dissection at the posterolateral surface of the UP revealed a separate perivascular fibroligamentous tissue (PVFLT) that originates from the PLL. The recognition of the PVFLT may provide for safe surgery by protecting the neural and vascular structures during decompression in the UV region.

Morphometric evaluation of the uncinate process and its importance in surgical approaches to the cervical spine: a cadaveric study

“…(27) In Russo et al's study, the height of the UP was 5.4 ± 1.5 mm on the left side and 5.6 ± 1.2 mm on the right side at the C2-3 level, 5.9 ± 1.3 mm on the left side and 6.0 ± 1.3 mm on the right side at the C3-4 level, 5.7 ± 1.2 mm on the left side and 6.1 ± 0.7 mm on the right side at the C4-5 level, 6.3 ± 2.2 mm on the left side and 6.2 ± 1.8 mm on the right side at the C5-6 level on cadavers. (24) The results of the present study support the findings of Uğur et al (8) and Yilmazlar et al, (20) in which the height of the UP increased from C3 to C7, with the maximum height recorded at C7 (Table III).…”

“…For this reason, this tissue must be dissected completely before resection. (11,16,19,20) Cervical spondylosis also narrows the foramen, making surgery more challenging in patients with this pathology. (11,19,21) Some authors refer to the line between the UP and the medial border of the uncovertebral joint as a safety line, although the short distance between the UP and vertebral artery reduces the safety of surgery.…”

“…At different cervical levels, the surgical method may be changed. (20) As the UP forms the lateral border of a corpectomy, knowledge of the distance between the right and left apex of the UP is important, so as to determine the width of the UP during corpectomy. The distance between the right and left apex of the UP decreases gradually from C6 to C3.…”

“…An increase in the width of the UP due to osteophyte formation in the UP may result in intervertebral foraminal stenosis and neural compression. (20) Resection of the UP or osteophyte is generally done mediolaterally, and the desired width of the UP is approximately 20%-25% of the vertebral body. (25) The medial border length of the UP on CT was also noted in the present study.…”

Clinical anatomy and clinical significance of the cervical intervertebral foramen: a review

“…The uncinate process and its covering ligaments are barriers that prevent the nerve root and the vertebral artery against damage [51]. The posterior longitudinal ligament lies posteriorly of the vertebral bodies and has two loosely connected layers named the anterior layer and the posterior layer [6,20] …”