Are spinal cord and medulla samples from embalmed donors suitable for histological examination? A pilot study

A general belief exists that tissue from anatomical donors, especially from the central nervous system (CNS), may not be suitable for histological investigation. This is based on the idea that fixation routinely used in embalming whilst optimal for enabling dissection, insufficiently preserves tissue architecture at the cellular level. However, anatomical donors represent a precious resource for microscopical investigation, provided that preservation is sufficient to enable recognition of structures at the histological level. This could considerably extend the biomedical knowledge currently gained from donations. In this study, we addressed this question and examined histologically, samples of medulla and spinal cord from donors from the Anatomical Gift Programme of RCSI in Dublin. Samples of medulla and spinal cord in the cervical, thoracic and lumbar regions were obtained with appropriate permissions from four different donors that had been previously embalmed for routine anatomical examination. The tissue obtained was processed for paraffin embedding and routine histology. Analysis revealed that several features were identifiable with good histological detail. A scoring system was applied to evaluate the level of histological preservation in the various samples by assessing the following parameters: tissue integrity, presence of leptomeninges along the entire section surface, distinction/adherence grey/white matter, identification of neurons, other cell nuclei, neuropil pattern, capillaries and other intraneural vessels. Lumbar spinal cord and to a lesser extent medulla and cervical spinal cord showed on average good quality of preservation. Conversely, thoracic spinal cord tended, in general, to be less well preserved. We can conclude that spinal cord and medulla samples from embalmed donors can be suitable for histological examination. These findings open new avenues of study of spinal cord and brain stem anatomy on cadaveric tissue from donors already existing in anatomy donation programmes. These results also pave the way for the potential development of new human models of study useful to spinal cord and brain stem researchers. Finally, this expands considerably the impact of the generosity of anatomical donors for the advancement of biomedical knowledge.