Background: Deep brain stimulation (DBS) is widely used to treat advanced Parkinson’s disease, other movement and psychiatric disorders. DBS implantation requires application of a stereotactic frame throughout a lengthy procedure, making it uncomfortable and tiring. We designed a stereotactic cube to stage the operation, perform frameless microelectrode recording (MER) and fix the DBS. Methods: The 15-mm cube is implanted in a burr hole using bone cement. It contains 5 parallel trajectories (central + 4 around). It is aligned by stereotactic frame so that central trajectory reaches the target. Frameless MER is performed by attaching a micro-driver to the cube using 2–5 cannulae (4 cm). The DBS is fixed to the cube by a mini-plate and 1 screw. Ninety-six cubes were compared with 43 Bennet spheres (BS). Results: No cube moved compared to 2 (5%) BS (p < 0.05). The final trajectory was central in 64.4% of cubes compared to 47.5% of BS, and the final target was >2 mm out in no cubes compared to 12.5% of BS (p < 0.01). Infection and haemorrhage were observed in 2.5% and 3.3% of cubes, respectively, while 5% of BS developed infection, 5% haemorrhage and 7.5% skin erosion. Conclusions: This method is simple and effective in staging DBS procedures, performing frameless MER and DBS implantation, fixation and revision.

Sixty-two cases of thalamic pallidal and subthalamic surgery in Dundee were audited to assess the influence of physiological localisation on the procedure. Methods included microelectrode recording, evoked potential and stimulation techniques. Although anatomical localisation is improving with modern techniques, the physiological information is still modifying the surgery in 67% of cases.

The unforgiving nature of the thalamus, the globus pallidus and the subthalamic nucleus necessitates precise localization of functional targets. This requires the total attention of both the patient and the surgeon. To maximize the concentration of the patient and provide the most accurate localization, we performed staged stereotactic functional procedures. The first stage was performed under general anesthesia to abolish any head movement. We fused CT and MRI images and correlated the fused images with a digitized Talairach brain atlas. We calculated the target coordinates and fixed a modified Bennett Sphere to the skull with the central hole defining the trajectory to the target. The surrounding 12 holes gave parallel trajectories to targets surrounding the anatomical target at 2-mm intervals. The second stage was performed at least a week later under local anesthesia. Microelectrode recording using three simultaneous channels was used to refine the target. Once the microelectrode recordings and macrostimulation confirmed the desired target, a lesion was created or an Activa neurostimulator was inserted. Our early results using this technique in 28 procedures (in 19 patients) indicate a good outcome in 86% and a technical failure in 1 patient.