Study of Impact of Stereotactic parameters on Microelectrode recording in Parkinson’s disease patients who underwent Subthalamic nucleus Deep brain stimulation

AIM: To study the impact of trajectory parameters on Microelectrode recording during Subthalamic nucleus deep brain stimulation surgery in PD patients MATERIALS AND METHODS: This is a retrospective study. On the day of surgery MRI was taken with frame on which planning was done using stereocalc and navigation systems and final coordinates of X, Y, Z, mid sagittal angle, axial angles were obtained. During surgery Microelectrode recording (MER) was done and with bed side examination final lead placement decided. Impact of trajectory angles on MER was studied using appropriate statistical analysis. RESULTS: Among 40 patients studied,mean age of patients and duration of disease were 55.65years and 7.95 years. Mean UPDRS OFF and ON scores were 60.7 and 15.4 respectively and mean MOCA score was 26.6. Distribution of type of recording differs significantly across mid sagittal angles among <15o vs >15o (P <0.05). Group of <15o for midsagittal angle and >75o for axial angle had highest percentage (60%) showing no recording when compared to others. Significantly higher proportion of cases with higher duration of PD had higher incidence of no recording and vice-versa (P <0.05). CONCLUSION: The study found a correlation between approach angle and the quality of MER. Results showed that a midsagittal angle > 15o and an axial angle < 75o produced better MERs. Although not statistically significant, this could suggest approach angles may have a role to achieve good microelectrode recordings. Larger prospective studies may be helpful to understand this further.