Subthalamic nucleus (STN) deep brain stimulation (DBS) is a well established treatment for patients with advanced Parkinson’s disease (PD) with medically intractable levodopa induced motor fluctuations and dyskinesias.1 Its practical limitations include cost, availability and need for specialised training, postoperative programming and periodic pulse generator replacement. Safety and hardware issues include infection, haemorrhage, lead breakage, skin erosions, pulse generator failure and cosmetic effects of the hardware. Complications and hardware issues have required temporary or permanent discontinuation of treatment in as many as 5–10% of patients.1

The efficacy of surgical intervention in STN was first demonstrated by placing subthalamic lesions in primates with MPTP induced parkinsonism.2 3 Parkinsonism was reversed but variable transient or persistent hemichorea resulted.3 Because of concerns that STN lesioning would cause hemiballismus in humans, STN DBS was introduced first in nearly all centres. This effectively alleviated tremor, bradykinesia and rigidity while levodopa dosage and levodopa induced dyskinesias were both reduced.1 However, because of limited availability of DBS in some regions, subthalamotomy has also been explored as a surgical option in PD.4 5 6 7

Alvarez and colleagues8 confirm and update their previous published experience4 5 with subthalamotomy in PD (see page 979). Eighty-nine patients underwent unilateral subthalamotomy, 68 of whom were assessed in an unblinded fashion for 12–36 months following surgery. STN was targeted using semi-microrecording and microstimulation. A thermolytic lesion was placed in the dorsolateral region of the STN with a volume of 40–60 mm³ although postoperative MRI lesion analysis was not provided in this paper. Unified Parkinson’s Disease Rating Scale (UPDRS) motor scores while off medication improved by 50% at 12 months but improvement declined to 18% by 36 months. This magnitude of improvement at 12 months compares favourably with results …