Supine Position for the Prevention of Brain Shift in DBS Surgery: Technical Note and Novel Hypothesis “Water in the Inverted Cup” Mechanism

Research Article

Austin Neurosurg Open Access.2015;2(1): 1027.

Supine Position for the Prevention of Brain Shift in DBS Surgery: Technical Note and Novel Hypothesis “Water in the Inverted Cup” Mechanism

Miyagi Y1,2*, Samura K3, Kishimoto J4 and Chen X5

1Department of Stereotactic and Functional Neurosurgery, Kaizuka Hospital, Japan

2Department of Clinical Neurophysiology, Faculty of Medical Sciences, Kyushu University, Japan

3Department of Neurosurgery, Fukuoka University Hospital, Japan

4Center for Clinical and Translational Research, Kyushu University Hospital, Japan

5Department of Mechanical Engineering, Faculty of Engineering, Yamaguchi University, Japan

*Corresponding author: Miyagi Y, Department of Stereotactic and Functional Neurosurgery, Kaizuka Hospital, 7-7-27 Hakozaki, Higashi-ku, Fukuoka, 812-0053 Japan

Received: May 04, 2015; Accepted: June 11, 2015; Published: June 15, 2015


Many neurosurgeons perform DBS implantation in semi-sitting position and perforate a burr hole at the top of the cranium. We have empirically found that the supine position is the best position to minimize CSF leakage, intracranial air invasion and brain shift. The dynamics of brain shift can be explained by the “water in the inverted cup” hypothesis and the significance of the simultaneous fulfillment of three conditions: 1) supine position to minimize negative intracranial pressure; 2) arachnoid sealing to maximize surface tension of CSF; and 3) lower burr hole level to keep the balance of intra/extracranial pressures. Although 1) and 3) sound totally contradictory to conventional ideas, a simple but novel hypothesis the “water in the inverted cup” mechanism successfully explains the dynamics of CSF and air, the brain shift and the phenomena related to various procedures during stereotactic surgery.

Keywords: Brain shift; Supine position; Deep brain stimulation; Stereotactic neurosurgery; Intracranial pressure; Cerebrospinal fluid; Pneumocephalus; Surface tension


DBS: Deep Brain Stimulation; CSF: Cerebrospinal Fluid; MER: Microelectrode Recording; MR: Magnetic Resonance; AC: Anterior Commissure; PC: Posterior Commissure; CT: Computerized Tomography


Brain shift, which affects the clinical accuracy of a neuronavigation system in open craniotomy [1], has been recognized as one of significant factors which introduce error in DBS surgery as well [2-8]. Because brain shift is associated with outflow of CSF and intracranial air invasion, past research has indicated the significance of preventing CSF outflow using a head-up position [3,4,7-12] or arachnoid sealing around an inserted cannula and microelectrode [9,10,13-15]. Since we found that a brain shift occurs due to intracranial air invasion alone, even without significant CSF outflow [7], we have performed DBS surgeries at various angles of head elevation (ranging from supine to semi-sitting position) in order to find the optimal angle which would minimize the brain shift, and we have empirically recognized the significance of the simultaneous fulfillment of three conditions: supine position, arachnoid sealing, and burr-hole perforation around coronal suture. We report our findings of brain shift using these techniques and describe the details of two representative cases (the case with the largest brain shift in this series and the case with marked brain atrophy and large arachnoid cysts). The dynamics of brain shift during surgery are well explained by the “water in the inverted cup” phenomenon.


The three important points in this procedure were 1) supine position, 2) the burr hole perforation at the coronal suture level, and 3) minimal arachnoid penetration and arachnoid sealing.

The patient wore a stereotactic frame (Leksell model G, Elekta) on the head after local infiltration with 1% lidocaine hydrochloride. The frame was secured perpendicular to the facial plane (including forehead and bilateral zygomatic processes). After the localizer box was mounted on the head, 1.5-T MR images were obtained (Achieva 1.5T SE; PHILIPS). A 3D multiplanar T1-weighted scan (145 slices; voxel size 1.0 x 1.0 x 2.0 mm; TR 25.0 msec; TE 4.6 msec) and a T2- weighted coronal scan (40 slices; voxel size 0.0.53 x 0.53 x 2.0 mm; TR 2000 msec; TE 131 msec) were obtained. The head was secured to the frame holder of the operative table and the patient was placed in a completely supine position without any head flexion. Using stereotactic planning software (Leksell SurgiPlan® ver. 10.1.1, Elekta), the 3D coordinates of the AC and PC, bilateral targets and the stereotactic trajectory were determined.

The entry point was placed within 1cm of the coronal suture. Under a local infiltration with 1% lidocaine hydrochloride, the curved skin incision and dual-floor burr hole (14 mm) [16] was perforated at the entry point, and the dura mater was cauterized using a bipolar coagulator and cut in cruciform within 5 mm in diameter. After mounting two BenGun cannulas with multi-channel microelectrodes on the stereotactic arc, the pia mater was perforated with the 5mm tip of microelectrodes on the avascular point of the gyral surface, and the outer cannula was advanced ahead of the microelectrode tip. After setting two-channel cannulas with microelectrodes, the arachnoid around the penetration points was carefully sealed with fibrin glue to prevent CSF leakage. The MER was performed along two tracks 2 mm apart; first, central and lateral tracks for the right MER, followed by the second central and posterior tracks for the left MER. After the physiological localization of the target by both MER and macrostimulation methods [17], a DBS lead (model 3387 for pallidal simulation and model 3389 for subthalamic stimulation, Medtronic, Inc.) was inserted and anchored with the standard bur hole caps included in DBS kits [18]. With each procedure, the site and direction of the tip of the microelectrodes and DBS leads, as well as the intracranial air, were monitored with stereotactic X-ray films. The distal end of the lead was introduced subcutaneously to the parietal region by a tunneling tool and was embedded under the scalp. The subcutis of the incision was closed using a buried continuous suture with an absorbable suture, and the skin was closed with 4-0 Nylon.

Soon after the surgery, the patient was transferred to the CT and MR imaging units while being kept in a supine position. The postoperative 3D T1-weighted MR images were reconstructed and co-registered with the preoperative 3D images using Leksell SurgiPlan® software [19]. The information of lead location in each patient was utilized for contact selection and parameter setting in the postoperative DBS management. A neurostimulator with its extension cable was implanted under a general anesthesia on the second day postoperatively. The differences in 3D coordinates (ΔX, ΔY and ΔZ) of AC and PC were measured to directly analyze the brain shift. All values were expressed as the mean ± SD in the text, and the Box-Whisker graph (median, 1st and 3rd quartiles, lowest and highest) was used in Figure 1.