Slawomir Daniluk

Boston University, Boston, Massachusetts, United States

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Publications (6)16.9 Total impact

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    ABSTRACT: Targeting of the subthalamic nucleus (STN) during deep brain stimulation (DBS) surgery using standard atlas coordinates is used in some centers. Such coordinates are accurate for only a subgroup of patients, and subgroup size depends on the extent of inter-individual variation in STN position/size and degree to which atlas represents average anatomical relations. Few studies have addressed this issue. Sixty-two axial T(2)-weighted magnetic resonance (MR) images of the brain (1.5 T) were obtained before STN-DBS in 62 patients (37 males) with Parkinson's disease using a protocol optimized for STN visualization. Image distortion was within sub-millimeter range. Midcommissural point (MCP)-derived coordinates of STN borders, STN center, and other brain landmarks were obtained using stereotactic software. MR-derived measurements were compared to Schaltenbrand and Wahren Atlas. We evaluated 117 best-visualized STNs. STN dimensions and coordinates of its center were highly variable. STN lateral coordinate ranged 8.7 mm-14.5 mm from MCP, A-P coordinate 3.5 mm posterior to 0.5 mm anterior to MCP, and vertical coordinate 1.3 mm-6 mm below MCP. The antero-posterior nucleus dimension varied by 8 mm and lateral-medial dimension by 5.8 mm. Differences between mean values of MR-derived data sets and Atlas values were statistically significant but moderate, excluding AC-PC length, for which the Atlas value was below the 1st percentile of the MR data set. The STN lateral coordinate strongly correlated with the width of the third ventricle (r = 0.73, p < 0.001). It is now possible to directly evaluate STNs at 1.5 T with minimal image distortion, which reveals variation in STN position and dimensions in the range of nucleus size. This puts under question the rationale of use of standard STN coordinates during DBS surgery.
    No preview · Article · Oct 2009 · Acta Neurochirurgica
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    ABSTRACT: Although a few studies have quantified errors in the implantation of deep brain stimulation electrodes into the subthalamic nucleus (STN), a significant trend in error direction has not been reported. We have previously found that an error in axial plane, which is of most concern because it cannot be compensated for during deep brain stimulation programming, had a posteromedial trend. We hypothesized that this trend results from a predominance of a directionally oriented error factor of brain origin. Accordingly, elimination of nonbrain (technical) error factors could augment this trend. Thus, implantation accuracy could be improved by anterolateral compensation during target planning. Surgical technique was revised to minimize technical error factors. During 22 implantations, targets were selected on axial magnetic resonance imaging scans up to 1.5 mm anterolateral from the STN center. Using fusion of postoperative computed tomographic and preoperative magnetic resonance imaging scans, implantation errors in the axial plane were obtained and compared with distances from the lead to the STN to evaluate the benefit of anterolateral compensation. Twenty errors and the mean error had a posteromedial direction. The average distances from the lead to the target and to the STN were 1.7 mm (range, 0.8-3.1 mm) and 1.1 mm (range, 0.1-1.9 mm), respectively. The difference between the 2 distances was significant (paired t test, P < 0.0001). The lower parts of the lead were consistently bent in the posteromedial direction on postoperative scout computed tomographic scans, suggesting that a brain-related factor is responsible for the reported error. Elimination of the technical factors of error during STN deep brain stimulation implantation can result in a consistent posteromedial error. Implantation accuracy may be improved by compensation for this error in advance.
    No preview · Article · May 2009 · Neurosurgery
  • Keith G Davies · Slawomir Daniluk

    No preview · Article · Nov 2008 · Stereotactic and Functional Neurosurgery
  • Slawomir Daniluk · Keith Davies
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    ABSTRACT: Object. The subthalamic nucleus (STN) is currently recognized as the preferred target for deep brain stimulation (DBS) in patients with Parkinson disease (PD). If there is agreement in the literature that DBS improves motor symptoms significantly, the situation is less clear with respect to the side effects of this procedure. The goal of this study was to correlate the coordinate values of active electrode contacts with the amplitude of residual clinical symptoms and side effects using a mathematical approach. Methods. In this study the investigators examined a cohort of 41 patients with PD who received clinical benefits from DBS after stimulating electrodes had been implanted bilaterally into the STN. The combined scores of residual clinical symptoms plus side effects, including speech disturbance, postural instability, and weight gain, were fitted by using either inverted ellipsoidal exponentials or smooth splines. These analyses showed evidence of lower combined scores for stimulating contacts at an x coordinate approximately 12.0 to 12.3 mm lateral to the anterior commissure-posterior commissure (AC-PC) line and at a z coordinate approximately 3.1 to 3.3 mm under the AC-PC line. There was insufficient evidence for a preferred y coordinate location. Conclusions. The authors propose a "best" therapeutic ellipse area that is centered at an x, z location of 12.5 mm, 23.3 mm and characterized by an extension of 1.85 mm in the x direction and 2.22 mm in the z direction. Therapeutic electrode contacts located within this area are well correlated with the lowest occurrence of residual symptoms and the lowest occurrence of side effects independent of STN anatomical considerations. The lack of a significant result in the y direction remains to be explored further.
    No preview · Article · Mar 2008 · Journal of Neurosurgery
  • Keith G Davies · Slawomir Daniluk

    No preview · Article · Feb 2008 · Stereotactic and Functional Neurosurgery
  • Peter Novak · Slawomir Daniluk · Samuel A Ellias · Jules M Nazzaro
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    ABSTRACT: Accurate and fast localization of the subthalamic nucleus (STN) during intraoperative electrophysiological monitoring can improve the outcome of deep brain stimulation surgery. The authors show a simple method of detecting the STN that is based on an analysis of the high-frequency (> 500 Hz) background (HFB) activity of neurons. The HFB reflects multiunit spiking activity close to the recording electrode, and its characteristic profile, which is higher in the STN than in neighboring structures, and facilitates delineation of both the dorsal and ventral STN borders.
    No preview · Article · Feb 2007 · Journal of Neurosurgery