Mechanoreceptors in Ligamentum Flavum of Lumbar Spine

Rhyu, Kee Won; Shin, Jae Hyuk; Ha, Kee Yong

Abstract

STUDY DESIGN: Histologic analysis of the ligamentum flavum to determine the distribution of mechanoreceptors in the lumbarspine.
OBJECTIVES
To evaluate the distribution of mechanoreceptors in the ligamentum flavum and the quantitative changes according to the presence of degenerative change or segmental instability of the lumbar spine. SUMMARY OF LITERATURE REVIEW: Three types of mechanoreceptors were seen in the ligamentous structures of lumbar spine and they were found mainly in the interspinous/supraspinous ligament complex and the facet joint capsule. The numeric distribution of mechanoreceptors was suggested as the change of proprioception.
MATERIALS AND METHODS
The ligamentum flavums were obtained from forty-four patients who underwent surgical decompression for various spinal diseases. The patients were divided into three groups. Group 1(9 cases) was defined as the patients with-out degenerative changes. Group 2(15 cases) included the patients with degenerative changes without instability. In group 3(20cases), the patients had the degenerative changes and instability. The specimens were stained by modified gold-chloride method. The types and numbers of mechanoreceptor were checked in each group and the result was analysed statistically.
RESULTS
The total numbers of mechanoreceptors were 2.1+/-1.1, 2.0 +/-1.6, and 0.7+/-0.7 in type 1, 2, and 3. In group 1, the numbers of type 1, 2, and 3 were 2.1+/-0.9, 2.2+/-1.5, and 1.0 +/-0.5, respectively. In group 2, the numbers were 2.0 +/-1.3, 2.0 +/-1.9, and 0.5 +/- 0.6, respectively. In group 3, the numbers were 2.3 +/-1.1, 1.8 +/-1.4, and 0.7 +/-0.8, respectively. Statistically, the numbers of type 1 and type 2 had no difference and were greater than that of type 3. The numbers of type 1, 2, and 3 were not affected according to the presence of degenerative change or instability.
CONCLUSION
The mechanoreceptors were seen in ligamentum flavum also as well as interspinous/supraspinous ligament complex and facet joint capsule, and they were mainly slowly or rapidly adapting. The distribution of mechanoreceptors was not affected by the presence of degenerative change or instability. The authors suggest that the degenerative change or instability would not influence to the proprioception of the ligamentum flavum.