Purpose
Blindness during spinal surgery is rare, previous reports have attributed this complication to patient positioning, blood loss, hypotension or shock. Ophthalmoplegia after spinal surgery is even more unusual than visual loss, and only few reports exist in the literature. Moreover,magnetic resonance image (MRI) studies to differentiate between cavernous sinus thrombosis and direct compression of orbital contents have not been previously described. In this case we also did visually evoked potential(VEP), and fundus photography(first time ever) to achive deeper details about etiology of post operative visual loss (POVL).
Methods
A 52 year old male of atlantoaxial joint dislocation, for that spinal surgery was done in prone position, postoperative patient complaint of sudden painless decrease in vision in right eye. On examination the patient had perception of light(PL) - ve, and presence of relative afferent pupillary defect and decreased extra ocular movements in all gazes in right eye. There was also pallor of retina,attenuated arteries and central cherry red spot. Immediately ocular massage and paracentesis done, Nitroglycerine patch applied, intravenous methyl prednisolone started. MRI showed edema in right medial rectus and inferior oblique muscles. Visual evoked potentials (VEP) showed decreased amplitude and delayed latency. Fundus photography also done. At three month follow up there was no improvement.
Results
The causes of blindness was likely ischemia of the retina after venous congestion or temporary arterial occlusion resulting from prolonged prone with slight head down position and possibility of orbital compression by the headrest, could have contributed to impaired venous drainage, increase in IOP ( intra ocular pressure) and reduction in perfusion pressure.
Conclusions
Blindness during spinal surgery is irreversible and incurable. Mainly occurs due to prone position of the patient to prevent it a right position should be maintained so that facial and ocular compression can be avoided. Any change to the patient’s position must be reported to the anesthetist. Bradyarrhythmia or illnesses of heart conduction must be noted, as they may be signals of vagal stimulation of increased intraorbital pressure. Some minor precautiouns can prevent this dreadful complication.
Keywords: 688 retina •
613 neuro-ophthalmology: optic nerve