Evaluation of periprocedural anxiety during Gamma Knife radiosurgery (GKRS) frame fixation for brain lesions

Application of stereotaxy frame for gamma knife under local anesthesia creates anxiety and phobia in many patients. Vasovagal syncopal attacks and events of bradycardia are not infrequently seen. We tried to analyse the various factors affecting these events and set standards and safety recommendations for the procedure.

This prospective study was carried out in Gamma Knife Centre, AIIMS, New Delhi over a 6 month period between June, 2021- November, 2021. All patients coming to Gamma knife for various etiologies were asked to fill Hamilton Anxiety Rating Scale (HAM-A) before frame application. Baseline pulse rate was evaluated and with every pin application pulse rate was recorded. A VAS (visual analogue scale) for pain was also administered after the procedure. Twenty percent fall in pulse rate were considered as significant bradycardia. Intraprocedural syncopal events were also recorded.

A total of 141 patients were studied of which 6% patients had intraprocedural syncopal attacks requiring medical treatment while 32% patients had bradycardia. Having previous surgery, having breakfast before the procedure, duration of pin application, quantity of local anaesthetia, primary diagnosis, sex of patients were not found to alter the syncope or bradycardia events. Patients who were found anxious (score > 18 on HAM-A) had a significantly higher risk of having a procedural event. Previous history of syncope was also associated with 1.7 times more chances of developing Intraprocedural bradycardia.

Frame application for gamma-knife is a relatively safe procedure however procedure rooms should be equipped with emergency drugs and fluids for management of syncope. A Simple anxiety questionnaire can predict 'at risk' patients' for procedural events.