Unpublished Neuropathologic Mechanism Behind the Muscle Weakness/Paralysis and Gait Disturbances Induced by Sciatic Nerve Degeneration After Spinal Subarachnoid Hemorrhage: An Experimental Study

BACKGROUND: Adamkiewicz arteries vasospasm in spinal cord subarachnoid hemorrhage (SAH) can affect the spinal cord. Although muscle dysfunction of extremities is a common problem after spinal cord ischemia induced by SAH, to our knowledge there are no studies on degenerative changes in peripheral nerves. We studied the histopathologic changes in sciatic nerves after spinal SAH. METHODS: This study was carried out on 19 rabbits. Five of them were used as control animals, 5 were in the sham group, and 9 were in the study group. For the procedure, 0.5 cm(3) of serum saline for the sham group and autologous arterial blood for the study group was injected into the lumbar subarachnoid space at the L5 level. After 2 weeks of follow-up, the sciatic nerve roots at the L5-S3 levels with spinal cords and sciatic nerves were bilaterally extracted to the levels of the collum femoris. The specimens were evaluated by stereologic methods, and degenerated sciatic nerve axons were estimated by Cavalieri methods. Kruskal-Wallis and Mann-Whitney U tests were used for data analysis. Differences of P < 0.005 were evaluated as significant. RESULTS: The mean number of degenerated axon density per square millimeter of sciatic nerve at the collum femoris level was 7 +/- 2/mm(2) in the control group, 23 +/- 7/mm(2) in the sham group (P < 0.005), and 125 +/- 32/ mm(2) in the SAH group (P < 0.00005). Statistical analysis showed that spinal SAH may cause axonal degeneration in the peripheral nerves. CONCLUSIONS: We concluded that SAHs frequently affect the spinal cord and result in axonal injury to peripheral nerves, of which there is no mention in the literature.