Silent Twiddler syndrome despite dual-anchor fixation in deep brain stimulation: two case reports.

Background: Twiddler syndrome (TS) is a rare hardware-related complication in which manipulation or excessive mobility of an implanted pacemaker or implantable pulse generator (IPG) results in device malfunction. Traditionally, TS is diagnosed only after lead coiling, fracture, displacement, or loss of therapeutic efficacy, suggesting that it represents a late-stage manifestation of the condition. Cases: We report 2 patients with deep brain stimulation (DBS) systems who presented with a subjective sensation of increased IPG mobility during changes in body position. Neither patient demonstrated mechanical failure, lead displacement, or deterioration of DBS clinical benefit, and both IPGs had been implanted with two anchoring sutures fixed to the fascia. Furthermore, neither patient reported intentional manipulation of the device. Because of persistent discomfort and abnormal mobility, revision surgery was performed. Intraoperative findings confirmed early-stage TS in both cases. The IPGs were reimplanted into tailored subpectoral pockets and firmly secured to the fascia. Following revision, both patients experienced complete resolution of symptoms and maintained sustained therapeutic benefit from DBS. Conclusion: These cases suggest that a subjective perception of increased IPG mobility may represent a distinct pre-Twiddler clinical syndrome that precedes the development of classic TS and overt hardware failure. Early recognition of this underrecognized presentation and timely surgical intervention through pocket revision and device immobilization may prevent progression to lead damage, device malfunction, and serious neurological adverse events, while ensuring uninterrupted neuromodulation therapy.