Accuracy of frame-based and frameless systems for deep brain stimulation: A meta-analysis.

Deep brain stimulation (DBS) is an effective treatment for movement disorders. It relies on the accurate placement of leads within small nuclei in the basal ganglia. Traditionally, this has been done with great success using frame-based stereotaxy. More recently, frameless systems have been introduced, and several studies have investigated whether they can achieve a similar accuracy. The objective of this meta-analysis was to assess the difference in targeting accuracy between frameless and frame-based systems in deep brain stimulation, using prior studies reporting error in all cardinal directions. We recorded the mean error and standard deviation, and calculated the composite mean difference in error between frame-based and frameless methods using standard difference of means. A total of 76 papers were screened, 25 papers were further assessed, and 5 papers were included in the meta-analysis for a total of 425 DBS electrode placements evaluated. Standard difference of means analysis revealed a statistically significant benefit to frame-based stereotaxy for the x and y coordinates with p = 0.036 and p = 0.0025, respectively. There was no significant difference in the z coordinate. However, the mean differences between frame-based and frameless stereotaxy was small and the composite mean differences were found to be 0.3037 mm, 0.0305 mm, and 0.1630 mm in the x, y and z direction. Our analysis shows that frameless systems represent a reasonable alternative to frame-based methods. Though there was a statistically significant loss of accuracy with frameless methods, the size of this effect was very small and of questionable clinical significance.