Figure 1
Archimedes spirals evolution. A: Prior to staged bilateral Vim DBS, the patient was unable to draw Archimedes spirals with either hand due to severe tremor. B: After initial optimization of the left Vim DBS, his right-hand tremor improved. C: After right Vim lead implantation, there was unexpected ipsilateral worsening of right-hand tremor, and he was unable to engage a pen to paper or draw a spiral (similar to the pre-operative state). D: The left-hand tremor improved following right Vim DBS optimization. E: Following optimization of bilateral DBS, with an increase in left Vim amplitude, there was further improvement of tremor documented in both hands. Created with BioRender.com.
Table 1
Vim DBS Side Effect Troubleshooting Guided by Lead Localization.
| DYSARTHRIA | MUSCLE CONTRACTION | ATAXIA | PARESTHESIA | ||
|---|---|---|---|---|---|
| Lead position | Medial | Lateral | Lateral | Ventro-medial | Posterior |
| Structure | Medial Vim | Internal capsule | Cerebello-thalamic input | Vc | |
| Common programming strategies | Lowering amplitude or pulse width Changing electrode configuration (different contacts or bipolar configuration) Using interleaving or cycling | ||||
| Specific strategies | Using a combination of low frequency and high pulse width Choosing more dorsal contacts | Using segments to reduce lateral stimulation | Choosing more dorsal contacts | Using segments to reduce posterior stimulation | |
[i] Vim, ventralis intermedius nucleus; Vc, ventral caudal nucleus.
Figure 2
Dentatorubrothalamic tract (DRTT, solid lines) with non-decussating fibers (nd-DRTT, dashed lines). SCP; superior cerebellar peduncle. Vim; ventralis intermedius nucleus. Created with BioRender.com.