Deep Brain Stimulation (DBS) is a neurosurgical procedure that involves implanting electrodes into specific brain regions to deliver continuous electrical impulses. A small device, called an internal pulse generator (IPG), is placed beneath the collarbone to power these electrodes, which are primarily used to treat movement disorders like Parkinson’s disease and essential tremor. While DBS can offer significant symptom relief, it is an invasive therapy that carries distinct risks and limitations, which patients must understand before considering the procedure.
Risks Associated with the Surgical Procedure
The initial risks of DBS relate to the surgery itself, which involves opening the skull and placing leads deep within the brain. The most serious, though rare, acute complication is intracranial hemorrhage, or bleeding in the brain, with an incidence generally ranging from 0.5% to 3% of cases. This bleeding can potentially lead to a stroke, though the rate of major hemorrhage requiring intervention is lower, around 0.7%.
Infection is another acute risk, with reported rates between 2.8% and 9.95%, often localized at incision sites or involving the implanted hardware. Serious infections may necessitate the removal of the entire DBS system, followed by antibiotics. Furthermore, precise targeting is challenging, and a slightly misplaced electrode may compromise the therapeutic effect or cause unintended side effects.
Complications Related to the Implanted Device
After surgery, patients face potential mechanical and electrical complications related to the hardware. The electrode lead can shift or migrate out of its optimal position (0.6% to 5.1%). Lead migration reduces therapy effectiveness and often requires an additional surgical procedure to reposition the electrode.
The physical components can also break, with lead or extension cable fractures occurring in 1% to 15.2% of patients. These fractures disrupt the electrical circuit, leading to a sudden loss of therapeutic benefit and requiring surgical revision. Skin erosion, where the hardware wears through the skin near the pulse generator or cable path, is also reported (1.3% to 7.7%).
Adverse Physical Side Effects from Stimulation
Once activated, the electrical current can cause physical side effects if the stimulation spreads beyond the intended target to adjacent neural tissue. One common side effect is dysarthria, or difficulty with speech, manifesting as a strained voice or slurred words. Other motor symptoms, such as gait disturbances causing unsteadiness, can be induced, particularly in patients with bilateral implants.
Patients may also experience paresthesia (tingling or numbness) or involuntary muscle contractions in the face or limbs. These effects suggest the stimulation is too high or is reaching sensory or motor pathways outside the therapeutic zone. These side effects are often transient and can be reversed or eliminated by adjusting the IPG programming settings.
Behavioral and Mood Changes Following Therapy
DBS can affect non-motor aspects of a patient’s life, including mood, behavior, and cognition. A frequently reported psychological change is apathy (a lack of motivation or interest), which is a post-operative risk. Depression and anxiety are also reported; while linked to the disease, their severity can be influenced by the stimulation or the post-surgical reduction of medications.
In some instances, stimulation can lead to impulse control disorders, such as increased gambling, excessive shopping, or hypersexuality, particularly when near reward-system circuits. Conversely, a shift toward elevated mood states, including hypomania, has been observed. These behavioral changes necessitate careful psychiatric management and adjustments to the DBS programming or medication regimen.
Practical and Long-Term Management Drawbacks
Living with a DBS system involves significant long-term management and practical burdens. The financial cost is substantial, with initial surgery and device implantation costing approximately $30,000 to $100,000 in the US. Patients also face ongoing expenses, including an additional $17,000 to $28,000 in DBS-related healthcare costs annually in the first few years.
Regular clinic visits are necessary for programming adjustments, which maintain the optimal therapeutic effect and manage side effects. These visits can be frequent, sometimes averaging nearly seven follow-up appointments in the first year, representing a significant commitment. All DBS devices contain a battery that must be surgically replaced when depleted, typically every three to five years for non-rechargeable models.
Another major practical drawback is the restriction on certain medical procedures, most notably Magnetic Resonance Imaging (MRI) scans. While modern DBS systems are often “MRI-conditional,” they require specific protocols, such as using an “MRI Mode” and adhering to strict limits on magnetic field strength to prevent device heating and tissue damage. The DBS system is a management tool, not a cure, and requires continuous engagement with the healthcare team for the duration of its use.