The Clinical Standards of the Society of NeuroInterventional Sugery (SNIS) are not rules, but rather attempts to define principles of practice that should generally produce high quality care. The physician may exceed an existing standard as determined by the individual patient and available resources. The standards should not be deemed inclusive of all proper methods of care or exclusive of other methods of care that are reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure or course of conduct must be made by the physician in light of all circumstances presented by the individual situation. Adherence to the SNIS standards will not assure a successful outcome in every situation. It may be prudent to document the rationale for any deviation from these suggested standards in the physician’s policies and procedures manual or, if not stated therein, in the patient’s medical record.