gms | German Medical Science

Objective: Intraoperative microelectrode-recording (MER) for the exact localization of the target within the STN is a well-established procedure during Deep Brain Stimulation (DBS) in Parkinson's disease (PD). Autopsy findings showed histological changes surrounding the DBS-electrode as well as the MER-tracts (Sun, 2008). The aim of our study was to correlate the number of MERs to the reduction of the daily levodopa equivalent doses (LEDD) and to the improvement in the UPDRS to evaluate a potential tissue trauma with persisting supression of PD-symptoms.

Method: 48 patients with PD (13 female, 35 male) with a mean age of 63.2 years treated with DBS were included in our retrospective analysis. Based on patient charts and operation reports we analyzed age, gender, subtype of PD, number of intraoperative MERs, clinically tested trajectories, LEDD and UPDRS III preoperative and at 1 year follow-up. Data were studied by using linear regression analysis.

Results: The mean disease duration was 14.2 years. Preoperatively we found a mean LEDD of 1110.7 mg, postoperatively the LEDD was reduced to 557.27 mg. The UPDRS was 16.4 preoperatively in the ON state and 52.4 in the OFF state. Postoperatively the UPDRS was 11.1. There was no significant correlation between number of intraoperative MERs or clinically tested trajectories and the postoperative reduction of LEDD. As well as there was no correlation between the number of MERs or clinically tested electrodes and the improvement in the UPDRS. Also in a side separate analysis there was no significant effect.

Conclusions: Contrasting previous histological findings our data suggest, that the tissue trauma by the electrodes does not cause a clinically relevant persisting lesioning effect suppressing PD-symptoms. However, prospective clinical evaluations including the patients' OFF-state will be necessary to corroborate these data.