The role of spinal tissue scarring in the pathogenesis of progressive post-traumatic myelomalacia.

OBJECTIVES

Experimental spinal cord injury (SCI) with focal spinal tissue scarring was studied to better understand the progressive post-traumatic myelomalacia (PPM).

METHODS

Using a stereotactic device, the authors developed an acute compression of spinal cord at Th-10 in the adult rat. In Group A, the rat thoracic spinal cord was compressed epidurally with preservation of local cerebrospinal fluid (CSF) dynamics. In Group B (spinal tissue scarring), the rat thoracic spinal cord was compressed directly after disruption of meninges of dura mater and arachnoid membrane, followed by gelatine sponge sealing. All rats were maintained for 12 weeks after injury.

RESULTS

Imaging analysis revealed the significant increase of cystic cavitation in the contused spinal cord in Group B compared with Group A. Anterograde axonal tracing demonstrated that the labeled corticospinal axons had extended axonal sprouting into the nearby gray matter and displayed prominent dieback at the rostral interface of the spinal cord lesion in both groups. No significant difference in motor and sensory functions between the two groups was noted.

DISCUSSION

The new experimental model of PPM formation was devised. Spinal tissue scarring at the injury site may cause a tethering effect on the spinal cord, which may lead to significant alteration of the spinal cord parenchyma. Although the devastating effect of PPM on motor and sensory functions is still not resolved completely, the results in the present study suggest the importance of careful analysis in the treatment of PPM after SCI.