Spinal Cord Model Essay

Three different general types of spinal cord models consist of contusion, compression and transection \cite{rosenzweig2004}. Each model contains the different advantages and disadvantages depending on the observing study. When a blunt force exposes to the spinal cord without the destruction of the dura, it develops the contusion model which is the most general case in human \cite{jackson2004,calancie2005}. The impactor is the confined tool to induce the contusion model with repeatability because this device can control the weight or solenoid delivering to the spinal cord coupled with the computer monitoring. The advance of this equipment generates the superior erudition of the injury degree by the measurement of biomechanics information such as velocity, energy, etc. This model conducts the mimicking of the lesions in human case better than the transection model \cite{anderson1992}. The disadvantage of the contusion model is the difficulty to differentiate between the regenerated and spare tissue compared with the transection model.
The compression model is incurred by the aneurysm clip \cite{rivlin1978}, compression balloon \cite{vanicky2001} and forceps \cite{borgens2000}. The different degree of SCI can be obtained by the compression time and compression strength adjustment. A neuropathology of SCI in human can be studied by this model since the beginning phase which is the spreading hemorrhagic necrosis and edema until the ending phase which is the formation of the central cyst at the chronic phase. Generally, the observation of this compression model is the SCI pathophysiology \cite{fehlings1989}, neuroprotective agents \cite{schwartz2001} and decompression time \cite{guha1987}. The transection model is hardly found in the human case.
However, many studies which are used the implantation device use this model for observing the axon regeneration. The opening of dura is the necessary for this model and a sharp penetrating force penetrates into the spinal cord for cutting some or all spinal cord \cite{rosenzweig2004}. Normally, the lateral hemisection or dorsal hemisection is preferred than full transection. Because the function of bladder and bowel are sufficiently preserved. Then, the post-operative care is easier than full transection model and the survival rate is increased. In dorsal hemisection procedure, the major components of the corticospinal tract, the dorsal column, and rubrospinal tract are damaged leading to the impairment of the paw placement during walking and overground locomotion. Therefore, the accuracy, strength, and velocity in left and right hindlimbs are affected
\cite{zorner2010}.