Can E12 sheet plastination be used to examine the presence and incidence of intra-articular spinal meniscoids?

Objectives: The role of intra-articular meniscoids in spinal pathology is unclear, and their anatomy not well understood. Spinal meniscoids have been identified in research using dissection and imaging. No previous studies have identified these structures using E12 sheet plastination; such methods of visualising meniscoids are likely of value in research and education. Our aim was to examine the presence of spinal meniscoids in cadaver sections that had undergone E12 sheet plastination. Methods: The lateral atlantoaxial and cervical, thoracic and lumbar zygapophyseal joints were inspected in two female cadavers (65, 86 years) that had undergone E12 sheet plastination in 2 mm sagittal and transverse sections. Each slice was photographed on a light-box then inspected under magnification to identify individual joints, then each joint assessed for the presence of meniscoids. Results: From 281 photographs, 92 zygapophyseal and four lateral atlantoaxial joints were identified. In sagittal sections, 24 meniscoids were identified in atlantoaxial and cervical joints and 32 meniscoids in the thoracic spine. In transverse sections, 14 meniscoids were identified in the thoracic spine and 12 meniscoids in the lumbar spine. Meniscoids were identified in all atlantoaxial and cervical joints, 78.9% of thoracic joints, and 80% of lumbar joints. Conclusion: Spinal meniscoids were effectively visualised on E12 sheet plastinates in all spinal regions. Meniscoid frequency was similar to previous reports for the atlantoaxial and cervical joints, and higher for thoracic and lumbar joints. Sheet plastinations can therefore be utilised in research and education exploring the anatomy and clinical significance of the meniscoids.