Single-trajectory deep brain stimulation of the posterior subthalamic area and subthalamic nucleus for dopamine-resistant parkinsonian tremor: A case report

Background

The subthalamic nucleus (STN) deep brain stimulation (DBS) usually requires high energy stimulation in the treatment of Parkinson's disease (PD) with medically refractory tremor, which may lead to axial disturbances compromising the anti-tremor effect.

Methods

One patient with PD developed from essential tremor suffered from severe levodopa-unresponsive tremor. He received bilateral DBS surgery targeting the posterior subthalamic area (PSA) and dorsal STN simultaneously using one single lead. A conventional frontal approach was applicable. Using standard clinical scales and objective gait analysis, we explored and compared the efficacy of PSA DBS, STN DBS, and PSA-STN co-stimulation.

Results

No severe adverse event was documented in this case. At the 2-year follow-up, having comparable efficacy on rigidity and bradykinesia, PSA stimulation, compared with STN stimulation, provided greater improvement in the tremor sub-score of the MDS Unified Parkinson’s Disease Rating Scale part III (UPDRS-III), the total score of the MDS UPDRS-III, and the score of Fahn-Tolosa-Marin tremor rating scale (FTM-TRS) part A&B. In addition, some of the gait parameters (i.e., turning duration and cadence) were better under PSA stimulation.

Conclusion

Single-trajectory simultaneous PSA and STN DBS with conventional frontal approach is feasible and is highly effective in one case with PD suffering from medically refractory tremor. This case provides insight into DBS targets selection for treatment-refractory tremor-dominant PD and suggests the potential for PSA as a complementary or alternative target in these cases.