Accuracy of various subthalamic nucleus targeting methods and an appropriated formula for Thai patients.

Objective: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has recently been the standard surgical treatment for Parkinson's disease. Besides appropriate selection of patients, precise STN targeting is the most crucial factor for good surgical outcomes. However, there is no single targeting method universally accepted as the most accurate technique. Thus, the authors studied the accuracy of various STN targeting methods and proposed a formula for Thai patients.

Material And Method: Sixteen patients with Parkinson's disease who fulfilled the intraoperative criteria of good STN targeting and had significant clinical improvements, without any stimulation-induced adverse effects, were included in the present study. Positions of the STN were determined by four targeting methods, direct targeting by axial T2W MRI, direct targeting by coronal T2W MRI, indirect targeting by anterior commissure-posterior commissure based formula and indirect targeting by adjustable digital Schaltenbrand-Wahren (SW) atlas, were compared with the final lead positions. The final lead positions by the four targeting methods were averaged to get an appropriate AC-PC based formula for Thai patients.

Results: The most accurate STN targeting method was axial T2W MRL followed by coronal T2W MRI, AC-PC based formula and the SW atlas, respectively. The averaged final lead positions obtained from the four methods was X = 11.5 +/- 1.0, Y = -3.3 +/- 1.0 and Z = -4.8 +/- 0.42 mm.

Conclusion: The direct targeting by axial T2W MRI yielded the highest accuracy and the appropriate STN formula for Thai patients appeared to be X = +/- 11.5, Y = -3.5 (-3.3) and Z = -5.0 (-4.8) mm.