A Strange Case of Downward Displacement of a Deep Brain Stimulation Electrode 10 Years Following Implantation: The Gliding Movement of Snakes Theory.

BACKGROUND

Despite the best efforts to ensure stereotactic precision, deep brain stimulation (DBS) electrodes can wander from their intended position after implantation. We report a case of downward electrode migration 10 years following successful implantation in a patient with Parkinson disease.

METHODS

A 53-year-old man with Parkinson disease underwent bilateral implantation of DBS electrodes connected to a subclavicular 2-channel pulse generator. The generator was replaced 7 years later, and a computed tomography (CT) scan confirmed the correct position of both leads. The patient developed a gradual worsening affecting his right side 3 years later, 10 years after the original implantation. A CT scan revealed displacement of the left electrode inferiorly into the pons. The new CT scans and the CT scans obtained immediately after the implantation were merged within a stereotactic planning workstation (Brainlab).

RESULTS

Comparing the CT scans, the distal end of the electrode was in the same position, the proximal tip being significantly more inferior. The size and configuration of the coiled portions of the electrode had not changed. At implantation, the length was 27.7 cm; after 10 years, the length was 30.6 cm.

CONCLUSIONS

These data suggests that the electrode had been stretched into its new position rather than pushed. Clinicians evaluating patients with a delayed worsening should be aware of this rare event.