This study aimed to investigate the relationship between neuron density of superior cervical sympathetic ganglia and pupil diameter in subarachnoid hemorrhage.Material and Methods:
This study was conducted on 22 rabbits; 5 for baseline control, 5 SHAM group and 12, study group. Pupil diameters were measured via sunlight and ocular tomography on day 1 as the control values. Pupil diameters were remeasured after injecting 0.5 cc saline to the SHAM group, and autologous arterial blood into the cisterna magna of the study group. After 3 weeks, brain, superior cervical sympathetic ganglia and ciliary ganglia were extracted with peripheral tissues bilaterally and examined histopahologically. Pupil diameter values were compared with neuron densities of the sympathetic ganglia and ciliary ganglia were examined using stereological methods.Results:
Baseline values were, normal pupil diameter 7.180±620µm and mean neuron density of the superior cervical sympathetic ganglia, 6.321±510/mm3, degenerated neuron density of ciliary ganglia was 5±2/mm3 after histopathological examination in the control group. These values were measured as 6.850±578µm, 5.950±340/mm3 and 123±39/mm3 in the SHAM group and 9.910±840µm, 7.950±764/mm3 and 650±98/mm3 in the study group. A linear relationship was determined between neuron density of the superior cervical sympathetic ganglia and pupil diameters(p<0.005). Degenerated ciliary ganglia neuron density had an inverse effect on pupil diameters in all groups(p<0.0001).Conclusion:
Highly degenerated neuron density of ciliary ganglion is not responsible for pupil dilatation owing to parasympathetic pupilloconstructor palsy but high neuron density of pupillodilatatory superior cervical sympathetic ganglia should be considered an important factor on pupil dilatation.