Inward Lead Migration Years After Pallidal Deep Brain Stimulation

A woman in her late 60s with advanced Parkinson's disease underwent bilateral pallidal deep brain stimulation (DBS, Fig. 1A), which markedly improved dyskinesias (Table 1). Clinical benefit remained stable for 2 years. After relocation to a remote nursing home, follow-up was limited. Four years postoperatively, right-sided dyskinesias recurred. Head CT revealed ventral migration of the left DBS lead into the crural cistern (Fig. 1B–D). At revision, the burr hole ring and cap fixation system appeared intact; however, the lead had shifted ventrally without any mechanical damage. Repositioning and secure re-anchoring under fluoroscopy restored clinical improvement (Table 1). Although DBS lead migration has been reported,1, 2 inward migration is extremely rare. The initial trajectory may have placed the tip near the subarachnoid space adjacent to the optic tract (Fig. 1A), where cerebrospinal fluid pulsation and current flow gradually displaced it ventrally. Other contributing factors may include insufficient fixation or patient manipulation, as in Twiddler's syndrome.1, 2 Even after long-term stability, DBS leads may undergo delayed inward migration. Long-term surveillance, even with simple X-rays, should be considered, as migration can occur without trauma or device failure and may necessitate surgical revision. (1) Research project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript Preparation: A. Writing of the first draft, B. Review and Critique; Y.K.: 1C, 3A, 3B. H.S.: 1A, 1C, 3B. N.N.: 1C, 3B. Y.S.: 3B. R.T.: 3B. S.K.: 3B. H.T.: 1A, 1B, 1C, 3A, 3B. Ethical Compliance Statement: This study was approved by the Institutional Review Board of Medical Research Institute Kitano Hospital. Written informed consent was obtained from the patient's caregiver and appropriately documented. The authors affirm that they have read the Journal's position on ethical publication and confirm that this work complies with the guidelines outlined therein. Funding Sources and Conflicts of Interest: HT received Grant-in-Aid for Scientific Research (C) 21 K09116 and 24 K12298 from the Japan Society for the Promotion of Science. The authors declare that there are no conflicts of interest relevant to this work. Financial Disclosures for the Previous 12 Months: The authors would like to disclose the following. HS received honoraria from Medtronic for lectures. YT reported personal fees from Boston Scientific, AbbVie, Eisai, Ono Pharmaceutical, Kyowa Kirin, Sumitomo Pharma, Daiichi Sankyo, Takeda Pharmaceutical, Medtronic, Insightec, and Medixpost and grants from AbbVie outside the submitted work. HT reported personal fees from Boston Scientific, Insightec, Abbott, and Medtronic. The other authors declare that there are no additional disclosures to report. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.