I read your question and I understand your concern. From your description of the episodes they can indeed be a case of seizures. They shouldn t be related to the back surgery itself. The EEG being normal doesn t exclude the diagnosis as it can be the case in the interval without seizures. Regarding the tests I think apart from routine lab tests (including electrolytes and tests for autoimmune disease), brain imaging is also required as at this age usually seizures have an identifiable cause. Also the EEG can be repeated because repeated EEGs increase the chance of chancing upon epileptiform anomalies. If the seizures are frequent i would consider being admitted to a neurology clinic, in order for the seizures to be seen by personnel which is used to the features of epilepsy and more qualified to distinguish seizures from other attacks like psychogenic ones or syncope. There are specialized clinics where prolonged EEG accompanied by video recordings side by side make for a better evaluation. If the seizures are rare, you live in a remote area and the doctor never happens to see one, you could also yourself film the episodes (with your smartphone if you have one) and show them to your doctor to facilitate his evaluation of them. If the clinical signs are convincing a normal EEG shouldn t be an obstacle to starting treatment. I hope to have been of help.