Uncovering the Forgotten Effect of Superior Cervical Ganglia on Pupil Diameter in Subarachnoid Hemorrhage: An Experimental Study.
OBJECTIVE
To investigate the relationship between neuron density of the superior cervical sympathetic ganglia and pupil diameter in subarachnoid hemorrhage.


METHODS
This study was conducted on 22 rabbits; 5 for the baseline control group, 5 for the SHAM group and 12 for the study group. Pupil diameters were measured via sunlight and ocular tomography on day 1 as the control values. Pupil diameters were re-measured 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, the brain, superior cervical sympathetic ganglia and ciliary ganglia were extracted with peripheral tissues bilaterally and examined histopathologically. Pupil diameters were compared with neuron densities of the sympathetic ganglia and ciliary ganglia which were examined using stereological methods.


RESULTS
Baseline values were; normal pupil diameter 7.180±620 ?m 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±578 ?m, 5.950±340/mm3 and 123±39/mm3 in the SHAM group and 9.910±840 ?m, 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).


CONCLUSIONS
Highly degenerated neuron density of the ciliary ganglion is not responsible for pupil dilatation owing to parasympathetic pupilloconstrictor palsy, but high neuron density of the pupillodilatatory superior cervical sympathetic ganglia should be considered an important factor for pupil dilatation.
Umraniye Teaching and Research Hospital, Neurosurgery Clinic, Istanbul, Turkey.
Mehmet Resid
MR
Onen
Ilhan
I
Yilmaz
Leyla
L
Ramazanoglu
Mehmet Dumlu
MD
Aydin
Sadullah
S
Keles
Orhan
O
Baykal
Nazan
N
Aydin
Cemal
C
Gundogdu
D000818:Animals; D002946:Cisterna Magna / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D005726:Ganglia, Parasympathetic / Q000473:pathology / Q000503:physiopathology; D008297:Male; D015878:Mydriasis / Q000473:pathology* / Q000503:physiopathology; D009410:Nerve Degeneration / Q000473:pathology / Q000503:physiopathology; D009474:Neurons / Q000473:pathology / Q000502:physiology; D011680:Pupil / Q000502:physiology*; D011817:Rabbits; D013345:Subarachnoid Hemorrhage / Q000473:pathology* / Q000503:physiopathology; D017783:Superior Cervical Ganglion / Q000473:pathology* / Q000503:physiopathology