Five-Year Follow-Up of Bilateral Epidural Prefrontal Cortical Stimulation for Treatment-Resistant Depression.

Background: Epidural prefrontal cortical stimulation (EpCS) represents a novel therapeutic approach with many unique benefits that can be used for treatment-resistant depression (TRD).
Objective: To examine the long-term safety and efficacy of EpCS of the frontopolar cortex (FPC) and dorsolateral prefrontal cortex (DLPFC) for treatment of TRD.
Methods: Adults (N = 5) who were 21-80 years old with severe TRD [failure to respond to adequate courses of at least 4 antidepressant medications, psychotherapy and ≥20 on the Hamilton Rating Scale for Depression (HRSD24)] were recruited. Participants were implanted with bilateral EpCS over the FPC and DLPFC and received constant, chronic stimulation throughout the five years with Medtronic IPGs. They were followed for 5 years (2/1/2008-10/14/2013). Efficacy of EpCS was assessed with the HRSD24 in an open-label design as the primary outcome measure at five years.
Results: All 5 patients continued to tolerate the therapy. The mean improvements from pre-implant baseline on the HRSD24 were [7 months] 54.9% (±37.7), [1 year] 41.2% (±36.6), [2 years] 53.8% (±21.7), and [5 years] 45% (±47). Three of 5 (60%) subjects continued to be in remission at 5 years. There were 5 serious adverse events: 1 electrode 'paddle' infection and 4 device malfunctions, all resulting in suicidal ideation and/or hospitalization.
Conclusion: These results suggest that chronic bilateral EpCS over the FPC and DLPFC is a promising and potentially durable new technology for treating TRD, both acutely and over 5 years.
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