Acta Neurochir (2011) 153:2337–2341. DOI 10.1007/s00701-011-1130-2
Device-related infection is a common occurrence after deep brain stimulation (DBS) surgery, and may result in additional interventions and a loss of efficacy of therapy. This retrospective review aimed to evaluate the incidence, severity and management of device-related infections in 212 DBS procedures performed in our institute.
Methods Data on 106 patients, in whom 212 DBS procedures were performed between 2001 and 2011 at our institute by a single neurosurgeon (M.P.), were reviewed to assess the incidence, severity, management and clinical characteristics of infections in the first year after the implantation of a DBS system.
Results Infections occurred in 8.5% of patients and 4.2% of procedures. Of the nine infections, eight involved the neurostimulator and extensions, and one the whole system. The infections occurred 30.7 days after implantation: 7 within 30 days and 2 within 6 months. Infected and uninfected patients were comparable in terms of age, sex, indication for DBS implantation and neurostimulator location. In eight cases, the system components involved were removed and re-implanted after 3 months, while in one case the complete hardware was removed and not re-implanted.
Conclusion The overall incidence of postoperative infections after DBS system implantation was 4.2%; this rate decreased over time. All infections required further surgery. Correct and timely management of partial infections may result in successful salvage of part of the system.
Neurosurgery 69:1299–1306, 2011 DOI: 10.1227/NEU.0b013e31822b7069
Introduction of the portable intraoperative CT scanner provides for a precise and cost-effective way of fusing head CT images with high-tesla MRI for the exquisite definition of soft tissue needed for stereotactic targeting.
OBJECTIVE: To evaluate the accuracy of stereotactic electrode placement in patients undergoing deep brain stimulation (DBS) by comparing frame-based postimplantation intraoperative CT (iCT) images fused to a recent 3T-MRI with frame-based postimplantation intraoperative MRI (iMRI) alone.
METHODS: Frame-based DBS surgeries of 46 targets performed from February 8, 2007 to April 28, 2008 in 26 patients with the use of immediate postimplantation iMRI for target localization were compared with frame-based immediate postimplantation iCT fused with a recent 3T brain MRI for DBS localization of 50 targets performed from August 13, 2008 to February 18, 2010 in 26 patients. Pre- and postoperative mid anterior commissure-posterior commissure line coordinates and XYZ coordinates for preoperatively calculated DBS targets (intended target) and for the permanent DBS lead tips were determined. The differences between preoperative DBS target and postoperative permanent DBS lead-tip coordinates based on postimplantation intraoperative MRI for the MRI-alone group and based on postimplantation intraoperative CT fused to recent preoperative MRI in the CTMRI group were measured. The t test and Yuen test were used for comparison.
RESULTS: No statistically significant differences were found between the 2 groups when comparing the pre- and postperative changes in mid anterior commissure-posterior commissure line coordinates and XYZ coordinates.
CONCLUSION: Postimplantation DBS lead localization and therefore targeting accuracy was not significantly different between frame-based stereotactic 1.5T-MRI and framebased stereotactic head CT fused with recent 3T-MRI.
Acta Neurochir (2011) 153:2307–2318. DOI 10.1007/s00701-011-1081-7
The aim of our study was to evaluate discrepancies between the electrophysiologically and MRI-defined subthalamic nucleus (STN) in order to contribute to the ongoing debate of whether or not microelectrode recording (MER) provides additional information to imageguided targeting in deep brain stimulation.
Methods: Forty-four STNs in 22 patients with Parkinson’s disease were investigated. The three-dimensional MRI-defined STN was derived from segmentations of axial and coronal T2-weighted images. The electrophysiological STNs were generated from intraoperative MERs in 1,487 locations. The stereotactical coordinates of positive and negative STN recordings were re-imported to the planning software, where a three-dimensional reconstruction of the electrophysiological STN was performed and fused to the MRI data set. The estimated borders of the MRI- and MERSTN were compared. For statistical analysis Student’s t, Mann-Whitney rank sum and Fisher’s exact tests were used.
Results: MER-STN volumes, which were found outside the MRI-STN, ranged from 0 mm3 to 87 mm3 (mean: 45 mm3). A mean of 44% of the MER-STN volumes exceeded the MRI-STN (maximum: 85.1%; minimum: 15.1 %); 53.4% (n=793) of the microelectrode recordings were concordant and 46.6% (n=694) discordant with the MRI-defined anatomical STN. Regarding the dorsal borders, we found discrepancies between the MER- and MRI-STN of 0.27 mm (= mean; SD: 0.51 mm) on the first operated side and 1.51 mm (SD: 1.5 mm) on the second (p=0.010, t-test).
Conclusions: MER provides additional information to highresolution anatomical MR images and may help to detect the amount and direction of brain shift.
Acta Neurochir (2011) 153:2293–2306. DOI 10.1007/s00701-011-1166-3
The indications for deep brain stimulation (DBS) are expanding, and the feasibility and efficacy of this surgical procedure in various neurologic and neuropsychiatric disorders continue to be tested.
This review attempts to provide background and rationale for applying this therapeutic option to obesity and addiction. We review neural targets currently under clinical investigation for DBS—the hypothalamus and nucleus accumbens—in conditions such as cluster headache and obsessive-compulsive disorder. These brain regions have also been strongly implicated in obesity and addiction. These disorders are frequently refractory, with very high rates of weight regain or relapse, respectively, despite the best available treatments.
Methods We performed a structured literature review of the animal studies of DBS, which revealed attenuation of food intake, increased metabolism, or decreased drug seeking. We also review the available radiologic evidence in humans, implicating the hypothalamus and nucleus in obesity and addiction.
Results The available evidence of the promise of DBS in these conditions combined with significant medical need, support pursuing pilot studies and clinical trials of DBS in order to decrease the risk of dietary and drug relapse.
Conclusions Well-designed pilot studies and clinical trials enrolling carefully selected patients with obesity or addiction should be initiated.
Neurosurgery 69:1124–1130, 2011 DOI: 10.1227/NEU.0b013e3182296a42
The ventralis intermedius (VIM) nucleus of the thalamus is the primary surgical target for treatment of tremor. Most centers rely on indirect targeting based on atlas-defined coordinates rather than patient-specific anatomy, making intraoperative physiological mapping critical. Detailed identification of this target based on patientspecific anatomic features can help optimize the surgical treatment of tremor.
OBJECTIVE: To study colored fractional anisotropic images and diffusion tensor imaging (DTI) tractography to identify characteristic magnetic resonance appearances of the VIM nucleus.
METHODS: Four patients undergoing stereotactic surgery for essential tremor (ET) were retrospectively studied with analysis of magnetic resonance imaging-based colored fractional anisotropy (FA) images and fiber tractography. All were scanned with a 1.5-T magnetic resonance imaging unit, and all sequences were obtained before frame placement. Because the goal of this study was to identify the DTI characteristics of physiologically defined VIM nucleus, we selected and studied patients who had undergone DTI and had efficacious tremor control with intraoperative microlesioning effect and tremor reduction with less than 2.0-V stimulation.
RESULTS: Analysis of color FA maps, which graphically illustrate fiber directionality, revealed consistent anatomic patterns. The region of the VIM nucleus can be seen as an intermediate region where there is a characteristic transition of color. Presumptive VIM nucleus interconnectivity with sensorimotor cortex and cerebellum was identified via the internal capsule and the superior cerebellar peduncle, respectively. FA maps could also be used to distinguish segments of gray matter, white matter, and gray-white matter boundaries.
CONCLUSION: Analysis of DTI and FA maps on widely available 1.5-T magnetic resonance imaging yields clear identification of various structures key to neurosurgical targeting. Prospective evaluation of integrating DTI into neurosurgical planning may be warranted.
J Neurosurg 115:852–857, 2011.DOI: 10.3171/2011.5.JNS101457
Deep brain stimulation (DBS) is an established neurosurgical technique used to treat a variety of neurological disorders, including Parkinson disease, essential tremor, dystonia, epilepsy, depression, and obsessive-compulsive disorder. This study reports on the use of intraoperative MR imaging during DBS surgery to evaluate acute hemorrhage, intracranial air, brain shift, and accuracy of lead placement.
Methods. During a 46-month period, 143 patients underwent 152 DBS surgeries including 289 lead placements utilizing intraoperative 1.5-T MR imaging. Imaging was supervised by an MR imaging physicist to maintain the specific absorption rate below the required level of 0.1 W/kg and always included T1 magnetization-prepared rapid gradient echo and T2* gradient echo sequences with selected use of T2 fluid attenuated inversion recovery (FLAIR) and T2 fast spin echo (FSE). Retrospective review of the intraoperative MR imaging examinations was performed to quantify the amount of hemorrhage and the amount of air introduced during the DBS surgery.
Results. Intraoperative MR imaging revealed 5 subdural hematomas, 3 subarachnoid hemorrhages, and 1 intraparenchymal hemorrhage in 9 of the 143 patients. Only 1 patient experiencing a subarachnoid hemorrhage developed clinically apparent symptoms, which included transient severe headache and mild confusion. Brain shift due to intracranial air was identified in 144 separate instances.
Conclusions. Intraoperative MR imaging can be safely performed and may assist in demonstrating acute changes involving intracranial hemorrhage and air during DBS surgery. These findings are rarely clinically significant and typically resolve prior to follow-up imaging. Selective use of T2 FLAIR and T2 FSE imaging can confirm the presence of hemorrhage or air and preclude the need for CT examinations
J Neurosurg 115:301–309, 2011. DOI: 10.3171/2011.3.JNS101642
Correct lead location in the desired target has been proven to be a strong influential factor for good clinical outcome in deep brain stimulation (DBS) surgery. Commonly, a surgeon’s first reliable assessment of such location is made on postoperative imaging. While intraoperative CT (iCT) and intraoperative MR imaging have been previously described, the authors present a series of frameless DBS procedures using O-arm iCT.
Methods. Twelve consecutive patients with 15 leads underwent frameless DBS placement using electrophysiological testing and O-arm iCT. Initial target coordinates were made using standard indirect and direct assessment. Microelectrode recording (MER) with kinesthetic responses was performed, followed by microstimulation to evaluate the side-effect profile. Intraoperative 3D CT acquisitions obtained between each MER pass and after final lead placement were fused with the preoperative MR image to verify intended MER movements around the target area and to identify the final lead location. Tip coordinates from the initial plan, final intended target, and actual lead location on iCT were later compared with the lead location on postoperative MR imaging, and euclidean distances were calculated. The amount of radiation exposure during each procedure was calculated and compared with the estimated radiation exposure if iCT was not performed.
Results. The mean euclidean distances between the coordinates for the initial plan, final intended target, and actual lead on iCT compared with the lead coordinates on postoperative MR imaging were 3.04 ± 1.45 mm (p = 0.0001), 2.62 ± 1.50 mm (p = 0.0001), and 1.52 ± 1.78 mm (p = 0.0052), respectively. The authors obtained good merging error during image fusion, and postoperative brain shift was minimal. The actual radiation exposure from iCT was invariably less than estimates of exposure using standard lateral fluoroscopy and anteroposterior radiographs (p < 0.0001).
Conclusions. O-arm iCT may be useful in frameless DBS surgery to approximate microelectrode or lead locations intraoperatively. Intraoperative CT, however, may not replace fundamental DBS surgical techniques such as electrophysiological testing in movement disorder surgery. Despite the lack of evidence for brain shift from the procedure, iCT-measured coordinates were statistically different from those obtained postoperatively, probably indicating image merging inaccuracy and the difficulties in accurately denoting lead location. Therefore, electrophysiological testing may truly be the only means of precisely knowing the location in 3D space intraoperatively. While iCT may provide clues to electrode or lead location during the procedure, its true utility may be in DBS procedures targeting areas where electrophysiology is less useful. The use of iCT appears to reduce radiation exposure compared with the authors’ traditional frameless technique.
Neurosurgery 69:294–300, 2011 DOI: 10.1227/NEU.0b013e318214abda
Deep brain stimulation (DBS) at the subthalamic nucleus (STN) is an effective treatment for the motor manifestations of advanced medically refractory Parkinson disease. Because of the medial location of the target, surgical trajectories to the STN may violate the ipsilateral lateral ventricle.
OBJECTIVE: To determine whether violating the ventricle during STN DBS surgery is associated with postoperative confusion.
METHODS: A retrospective chart review of all STN implantation procedures for Parkinson disease performed by 1 surgeon between January 2005 and September 2008 was performed. Postoperative magnetic resonance imaging was performed in all cases, and each scan was reviewed for evidence of ventricular wall violation. All charts were reviewed for postoperative confusion and/or increased length of hospital stay.
RESULTS: A total of 145 leads were implanted in 81 patients over 102 admissions. Fortythree patients underwent contemporaneous bilateral lead implantation; 23 underwent unilateral implantation; and 18 underwent staged bilateral implantation. The cases of 8 patients were complicated by postoperative confusion and increased length of stay. Sixteen magnetic resonance imaging scans demonstrated evidence of ventricular wall violation including all 8 patients with postoperative confusion. The relative risk of having postoperative confusion after traversing the ventricle is 87 (P , .001).
CONCLUSION: Violating the ventricular system during STN DBS surgery correlated significantly with postoperative altered mental status and subsequent increased length of hospital stay. This finding may explain why cognitive complications are observed more frequently in Parkinson disease patients undergoing DBS at the STN compared with the internal globus pallidus.
Neurosurgery 69:207–214, 2011 DOI: 10.1227/NEU.0b013e318218c7ae
Knowledge of the anatomic location of the deep brain stimulation (DBS) electrode in the brain is essential in quality control and judicious selection of stimulation parameters. Postoperative computed tomography (CT) imaging coregistered with preoperative magnetic resonance imaging (MRI) is commonly used to document the electrode location safely. The accuracy of this method, however, depends on many factors, including the quality of the source images, the area of signal artifact created by the DBS lead, and the fusion algorithm.
OBJECTIVE: To calculate the accuracy of determining the location of active contacts of the DBS electrode by coregistering postoperative CT image to intraoperative MRI.
METHODS: Intraoperative MRI with a surrogate marker (carbothane stylette) was digitally coregistered with postoperative CT with DBS electrodes in 8 consecutive patients. The location of the active contact of the DBS electrode was calculated in the stereotactic frame space, and the discrepancy between the 2 images was assessed.
RESULTS: The carbothane stylette significantly reduces the signal void on the MRI to a mean diameter of 1.4 6 0.1 mm. The discrepancy between the CT and MRI coregistration in assessing the active contact location of the DBS lead is 1.6 6 0.2 mm, P < .001 with iPlan (BrainLab AG, Erlangen, Germany) and 1.5 6 0.2 mm, P < .001 with Framelink (Medtronic, Minneapolis, Minnesota) software.
CONCLUSION: CT/MRI coregistration is an acceptable method of identifying the anatomic location of DBS electrode and active contacts.
Neurosurgery 68:E1501–E1505, 2011 DOI: 10.1227/NEU.0b013e318210c859
Camptocormia is characterized by abnormal flexion of the thoracolumbar spine that increases during upright posture and abates in the recumbent position and has been reported to occur in patients with Parkinson disease. Camptocormia causes significant spinal and abdominal pain, impairment of balance, and social stigma.
CLINICAL PRESENTATION: A 57-year-old woman with Parkinson disease developed severe camptocormia, which did not improve with trials of antiparkinsonian and muscle relaxant medications. The patient was successfully treated with bilateral globus pallidus interna deep brain stimulation surgery under general anesthesia. High-frequency neuromodulation afforded relief of camptocormia and improvement in Parkinson disease symptoms.
CONCLUSION: Camptocormia in Parkinson disease may represent a form of dystonia and can be treated effectively with chronic pallidal neuromodulation.
Acta Neurochir (2011) 153:1087–1095 DOI 10.1007/s00701-011-0953-1
Microelectrode recording (MER) is widely used during deep brain stimulation (DBS) procedures because MER can identify structural borders and eloquent structures, localize somatotopic arrangements, and provide an outline of the three-dimensional shapes of target nuclei. However, MER may cause intracranial hemorrhage. We performed single track MER during DBS procedures, analyzed the accuracy of electrode positioning with MRI, and compared the amount of air and the potential risk of intracranial hemorrhage.
Method A total of 46 electrodes were placed in 23 patients who suffered from advanced Parkinson’s disease and who underwent bilateral subthalamic nucleus DBS using single track MER. Each patient’s Unified Parkinson’s Disease Rating Scale (UPDRS) score and levo-dopa equivalent dosage (LED) were estimated pre- and postoperatively. The accuracy of electrode positioning and fontal air thickness was measured by a pre- or postoperative magnetic resonance imaging (MRI) merging technique.
Findings The mean electrode positioning error was 0.92 mm (0.3–2.94 mm). The mean frontal air thickness on postoperative MRI was 3.85 mm (0–10.3 mm), which did not affect the electrode accuracy statistically (p=0.730). A total of nine electrodes required repositioning after single-track MER because they affected microstimulation or because an abnormally short STN length was observed during MER. In this series, one patient suffered from an intracranial hemorrhage after surgery that appeared to be due to venous infarction rather than related to MER.
Conclusions Although MER can facilitate accurate positioning of electrodes, multi-track MER may increase the risk of intracranial hemorrhage. The accuracy of electrode positioning appears to be acceptable under single track MER during STN DBS with careful electrophysiological and neurological monitoring. The risk of intracranial hemorrhage appears to be minimal, especially in elderly patients with atrophic brains.
Neurosurgery 68:1069–1076, 2011 DOI: 10.1227/NEU.0b013e31820a1a20
Deep brain stimulation (DBS) has been proven to alleviate tremor of various origins. Distinct regions have been targeted. One explanation for good clinical tremor control might be the involvement of the dentatorubrothalamic tract (DRT) as has been suggested in superficial (thalamic) and inferior (posterior subthalamic) target regions. Beyond a correlation with atlas data and the postmortem evaluation of patients treated with lesion surgery, proof for the involvement of DRT in tremor reduction in the living, the scope of this work, is elusive.
OBJECTIVE: To report a case of unilateral refractory tremor in tremor-dominant Parkinson disease treated with thalamic DBS.
METHODS: Preoperative diffusion tensor imaging (DTI) was performed. Correlation with individual DBS electrode contact locations was obtained through postoperative fusion of helical computed tomography (CT) data with DTI fiber tracking.
RESULTS: Tremor was alleviated effectively. An evaluation of the active electrode contact position revealed clear involvement of the DRT in tremor control. A closer evaluation of clinical effects and side effects revealed a highly detailed individual fiber map of the subthalamic region with DTI fiber tracking.
CONCLUSION: This is the first time the involvement of the DRT in tremor reduction through DBS has been shown in the living. The combination of DTI with postoperative CT and the evaluation of the electrophysiological environment of distinct electrode contacts led to an individual detailed fiber map and might be extrapolated to refined DTI-based targeting strategies in the future. Data acquisition for a larger study group is the topic of our ongoing research.
Neurosurgery 68[ONS Suppl 1]:ons114–ons124, 2011. DOI: 10.1227/NEU.0b013e31820781bc
The efficacy of deep brain stimulation (DBS) is highly dependent on the accuracy of lead placement.
OBJECTIVE: To describe the use of intraoperative computed tomography (iCT) to confirm lead location before surgical closure and to study the accuracy of this technique.
METHODS: Fifteen patients underwent awake microelectrode-guided DBS surgery in a stereotactic frame. A portable iCT scanner (Medtronic O-arm) was positioned around the patient’s head throughout the procedure and was used to confirm lead location before fixation of the lead to the skull. Images were computationally fused with preoperative magnetic resonance imaging (MRI), and lead tip coordinates with respect to the midpoint of the anterior commissure-posterior commissure line were measured. Tip coordinates were compared with those obtained from postoperative MRI.
RESULTS: iCT was integrated into standard frame-based microelectrode-guided DBS surgery with a minimal increase in surgical time or complexity. Technically adequate 2-dimensional and 3-dimensional images were obtained in all cases. Head positioning and fixation techniques that allow unobstructed imaging are described. Lead tip measurements on iCT fused with preoperative MRI were statistically indistinguishable from those obtained with postoperative MRI.
CONCLUSION: iCT can be easily incorporated into standard DBS surgery, replaces the need for C-arm fluoroscopy, and provides accurate intraoperative 3-dimensional confirmation of electrode tip locations relative to preoperative images and surgical plans. iCT fused to preoperative MRI may obviate the need for routine postoperative MRI in DBS surgery. Technical nuances that must be mastered for the efficient use of iCT during DBS implantation are described.
Neurosurgery 67:1745–1756, 2010 DOI: 10.1227/NEU.0b013e3181f74105
Deep brain stimulation (DBS) surgery is used for treating movement disorders, including Parkinson disease, essential tremor, and dystonia. Successful DBS surgery is critically dependent on precise placement of DBS electrodes into target structures. Frequently, DBS surgery relies on normalized atlas-derived diagrams that are superimposed on patient brain magnetic resonance imaging (MRI) scans, followed by microelectrode recording and macrostimulation to refine the ultimate electrode position. Microelectrode recording carries a risk of hemorrhage and requires active patient participation during surgery.
OBJECTIVE: To enhance anatomic imaging for DBS surgery using high-field MRI with the ultimate goal of improving the accuracy of anatomic target selection.
METHODS: Using a 7-T MRI scanner combined with an array of acquisition schemes using multiple image contrasts, we obtained high-resolution images of human deep nuclei in healthy subjects.
RESULTS: Superior image resolution and contrast obtained at 7 T in vivo using susceptibility-weighted imaging dramatically improved anatomic delineation of DBS targets and allowed the identification of internal architecture within these targets. A patient-specific, 3-dimensional model of each target area was generated on the basis of the acquired images.
CONCLUSION: Technical developments in MRI at 7 T have yielded improved anatomic resolution of deep brain structures, thereby holding the promise of improving anatomicbased targeting for DBS surgery. Future study is needed to validate this technique in improving the accuracy of targeting in DBS surgery.
Neurosurgery 67:957–963, 2010 DOI: 10.1227/NEU.0b013e3181ec49c7
Bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) was shown to be effective in cervical dystonia refractory to medical treatment in several small short-term and 1 long-term follow-up series. Optimal stimulation parameters and their repercussions on the cost/benefit ratio still need to be established.
OBJECTIVE: To report our long-term outcome with bilateral GPi deep brain stimulation in cervical dystonia.
METHODS: The Toronto Western Spasmodic Torticollis Rating Scale was evaluated in 10 consecutive patients preoperatively and at last follow-up. The relationship of improvement in postural severity and pain was analyzed and stimulation parameters noted and compared with those in a similar series in the literature.
RESULTS: The mean (standard deviation) follow-up was 37.6 (16.9) months. Improvement in the total Toronto Western Spasmodic Torticollis Rating Scale score as evaluated at latest follow-up was 68.1% (95% confidence interval: 51.5-84.6). In 4 patients, there was dissociation between posture severity and pain improvement. Prevalently bipolar stimulation settings and high pulse widths and amplitudes led to excellent results at the expense of battery life.
CONCLUSION: Improvement in all 3 subscale scores of the Toronto Western Spasmodic Torticollis Rating Scale with bilateral GPi deep brain stimulation seems to be the rule. Refinement of stimulation parameters might have a significant impact on the cost/ benefit ratio of the treatment. The dissociation of improvement in posture severity and pain provides tangible evidence of the complex nature of cervical dystonia and offers interesting insight into the complex functional organization of the GPi.
Neurosurgery 67:1088–1093, 2010 DOI: 10.1227/NEU.0b013e3181ecc887
Image-guided neuronavigation has largely replaced stereotactic frames when precise, real-time anatomic localization is required during neurosurgical procedures. However, some procedures, including placement of deep-brain stimulation (DBS) leads for the treatment of movement disorders, are still performed using frame-based stereotaxy. Despite the demonstration of comparable accuracy between frame-based and ‘‘frameless’’ image-guided approaches, the clinical efficacy of frameless DBS placement has never been reported.
OBJECTIVE: To analyze the outcomes of subthalamic nucleus (STN) DBS using the frameless technique for the treatment of Parkinson’s disease (PD).
METHODS: Of 31 subjects (20 men) with PD for 10 6 4 years, 28 had bilateral STN DBS and 3 had unilateral STN DBS. The Unified Parkinson’s Disease Rating Scale (UPDRS) motor scale (III) and total medication doses were assessed before surgery on and off medication and off medication/ON DBS (off/ON) after 6 to 12 months of STN DBS.
RESULTS: There was a 58% improvement from bilateral STN DBS in the UPDRS III (40 6 16 preoperatively off, 17 6 11 off/ON) 9.6 6 1.9 months after surgery (P , .001). This compared favorably with the published outcomes using the frame-based technique. All motor subscores improved significantly (P , .01). The mean reduction in medication was 50%. No intraoperative complications occurred, but one subject with hypertension died of a delayed hemorrhage postoperatively. Two subjects developed postoperative infections that required lead removal and antibiotics.
CONCLUSIONS: Bilateral STN DBS for PD performed by an experienced team using a frameless approach results in outcomes comparable to those reported with the use of the frame-based technique.
J Neurosurg 113:639–647, 2010.DOI: 10.3171/2010.3.JNS091385
A challenge associated with deep brain stimulation (DBS) in treating advanced Parkinson disease (PD) is the direct visualization of brain nuclei, which often involves indirect approximations of stereotactic targets. In the present study, the authors compared T2*-weighted images obtained using 7-T MR imaging with those obtained using 1.5- and 3-T MR imaging to ascertain whether 7-T imaging enables better visualization of targets for DBS in PD.
Methods. The authors compared 1.5-, 3-, and 7-T MR images obtained in 11 healthy volunteers and 1 patient with PD.
Results. With 7-T imaging, distinct images of the brain were obtained, including the subthalamic nucleus (STN) and internal globus pallidus (GPi). Compared with the 1.5- and 3-T MR images of the STN and GPi, the 7-T MR images showed marked improvements in spatial resolution, tissue contrast, and signal-to-noise ratio.
Conclusions. Data in this study reveal the superiority of 7-T MR imaging for visualizing structures targeted for DBS in the management of PD. This finding suggests that by enabling the direct visualization of neural structures of interest, 7-T MR imaging could be a valuable aid in neurosurgical procedures.
Neurosurg Focus 29 (2):E3, 2010. (DOI: 10.3171/2010.4.FOCUS10103)
Deep brain stimulation (DBS) is the treatment of choice for otherwise healthy patients with advanced Parkinson disease who are suffering from disabling dyskinesias and motor fluctuations related to dopaminergic therapy. As DBS is an elective procedure, it is essential to minimize the risk of morbidity. Further, precision in targeting deep brain structures is critical to optimize efficacy in controlling motor features. The authors have already established an operational checklist in an effort to minimize errors made during DBS surgery. Here, they set out to standardize a strict, step-by-step approach to the DBS surgery used at their institution, including preoperative evaluation, the day of surgery, and the postoperative course. They provide careful instruction on Leksell frame assembly and placement as well as the determination of indirect coordinates derived from MR images used to target deep brain structures. Detailed descriptions of the operative procedure are provided, outlining placement of the stereotactic arc as well as determination of the appropriate bur hole location, lead placement using electrophysiology, and placement of the internal pulse generator. The authors also include their approach to preventing postoperative morbidity. They believe that a strategic, step-by-step approach to DBS surgery combined with a standardized checklist will help to minimize operating room mistakes that can compromise targeting and increase the risk of complication.
Neurosurg Focus 29 (2):E13, 2010. DOI: 10.3171/2010.5.FOCUS1094
The aim of this study was to review the indications for and results of deep brain stimulation (DBS) of the posterior hypothalamus (pHyp) in the treatment of drug-refractory and severe painful syndromes of the face, disruptive and aggressive behavior associated with epilepsy, and below-average intelligence. The preoperative clinical picture, functional imaging studies, and overall clinical results in the literature are discussed.
Methods. All patients underwent stereotactic implantation of deep-brain electrodes within the pHyp. Data from several authors have been collected and reported for each clinical entity, as have clinical results, adverse events, and neurophysiological characteristics of the pHyp.
Results. The percentage of patients with chronic cluster headache who responded to DBS was 50% in the overall reported series. The response rate was 100% for short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and for chronic paroxysmal hemicrania, although only 2 patients and 1 patient, respectively, have been described as having these conditions. None of the 4 patients suffering from refractory neuropathic trigeminal pain benefited from the procedure (0% response rate), whereas all 5 patients (100%) affected with refractory trigeminal neuralgia (TN) due to multiple sclerosis (MS) and undergoing pHyp DBS experienced a significant decrease in pain attacks within the first branch of cranial nerve V. Six (75%) of 8 patients presenting with aggressive behavior and mental retardation benefited from pHyp stimulation; 6 patients were part of the authors’ series and 2 were reported in the literature.
Conclusions. In carefully selected patients, DBS of the pHyp can be considered an effective procedure for the treatment of refractory trigeminal autonomic cephalalgias, aggressive behavior, and MS-related TN in the first trigeminal branch. Only larger and prospective studies along with multidisciplinary approaches (including, by necessity, neuroimaging studies) can lead us to better patient selection that would reduce the rate of nonresponders.
Acta Neurochir DOI 10.1007/s00701-010-0742-2
The safe and reversible nature of deep brain stimulation (DBS) has allowed movement disorder neurosurgery to become commonplace throughout the world. Fundamental understanding of individual patient’s anatomy is critical for optimizing the effects and side effects of DBS surgery. Three patients undergoing stereotactic surgery for movement disorders, at the institution’s intraoperative magnetic resonance imaging operating suite, were studied with fiber tractography. Stereotactic targets and fiber tractography were determined on preoperative magnetic resonance imagings using the Schaltenbrand–Wahren atlas for definition in the BrainLab iPlan software (BrainLAB Inc., Feldkirchen, Germany). Subthalamic nucleus, globus pallidus interna, and ventral intermediate nucleus targets were studied. Diffusion tensor imaging parameters used ranged from 2 to 8 mm for volume of interest in the x/y/z planes, fiber length was kept constant at 30 mm, and fractional anisotropy threshold varied from 0.20 to 0.45. Diffusion tensor imaging tractography allowed reliable and reproducible visualization and correlation between frontal eye field, premotor, primary motor, and primary sensory cortices via corticospinal tracts and corticopontocerebellar tracts. There is an apparent increase in the number of cortical regions targeted by the fiber tracts as the region of interest is enlarged. This represents a possible mechanism of the increased effects and side effects observed with higher stimulation voltages. Currently available diffusion tensor imaging techniques allow potential methods to characterize the effects and side effects of DBS. This technology has the potential of being a powerful tool to optimize DBS neurosurgery
Acta Neurochir (2011) 153:2337–2341. DOI 10.1007/s00701-011-1130-2
