Effects of stereotactic neurosurgery on postural instability and gait in Parkinson’s disease
Bakker M, Esselink RA, Munneke M, Limousin-Dowsey P, Speelman HD, Bloem BR. (2004) Effects of stereotactic neurosurgery on postural instability and gait in Parkinson’s disease Movement Disorders, Sep;19(9):1092-9
These authors conducted a meta-analysis (large review of relevant research over a certain time) between 1997-2003, looking at postural instability and gait disability in patients that underwent surgery for PD (bilateral [both left and right] internal globus pallidus [area of the brain affected by PD], bilateral subthalamic nucleus [area of the brain affected by PD], and unilateral [either the left or the right side] pallidotomy [area of the brain affected by PD]). They reviewed 36 studies and found that the patients studied were not significantly different demographically (e.g. age, disease duration, medications) to each other, regardless of surgery type, prior to surgery. They also found that all surgeries improved posture instability and gait more predominantly in the OFF state, with a trend towards the greatest improvement with DBS-STN, then bilateral internal globus pallidus stimulation, followed by the unilateral pallidotomy. However, they noted that improvement was also noted in the ON state. Additionally, medication dosage was reduced only after DBS-STN and adverse effects in posture and gait were observed only with the bilateral pallidotomy. These authors also discuss the limitations of their review, including a lack of a control group, nonrandom assignment to surgery type, only looking at the first year after surgery, and inconsistent monitoring of adverse events.