Stereotactic and Functional Neurosurgery最新文献

Introduction: DBS efficacy depends on accuracy. CT-MRI fusion is established for both stereotactic registration and electrode placement verification. The desire to streamline DBS workflows, reduce operative time, and minimize patient transfers has increased interest in portable imaging modalities such as the Medtronic O-arm® and mobile CT. However, these remain expensive and bulky. 3D C-arm fluoroscopy (3DXT) units are a smaller and less costly alternative, albeit incompatible with traditional frame-based localization and without useful soft tissue resolution. We aimed to compare fusion of 3DXT and CT with pre-operative MRI to evaluate if 3DXT-MRI fusion alone is sufficient for accurate registration and reliable targeting verification. We further assess DBS targeting accuracy using a 3DXT workflow and compare radiation dosimetry between modalities.

Methods: Patients underwent robot-assisted DBS implantation using a workflow incorporating 3DXT which we describe. Two intra-operative 3DXT spins were performed for registration and accuracy verification followed by conventional CT post-operatively. Post-operative 3DXT and CT images were independently fused to the same pre-operative MRI sequence and co-ordinates generated for comparison. Registration accuracy was compared to 15 consecutive controls who underwent CT-based registration. Radial targeting accuracy was calculated and radiation dosimetry recorded.

Results: Data were obtained from 29 leads in 15 consecutive patients. 3DXT registration accuracy was significantly superior to CT with mean error 0.22 ± 0.03 mm (p < 0.0001). Mean Euclidean electrode tip position variation for CT to MRI versus 3DXT to MRI fusion was 0.62 ± 0.40 mm (range 0.0 mm-1.7 mm). In comparison, direct CT to 3DXT fusion showed electrode tip Euclidean variance of 0.23 ± 0.09 mm. Mean radial targeting accuracy assessed on 3DXT was 0.97 ± 0.54 mm versus 1.15 ± 0.55 mm on CT with differences insignificant (p = 0.30). Mean patient radiation doses were around 80% lower with 3DXT versus CT (p < 0.0001).

Discussion: Mobile 3D C-arm fluoroscopy can be safely incorporated into DBS workflows for both registration and lead verification. For registration, the limited field of view requires the use of frameless transient fiducials and is highly accurate. For lead position verification based on MRI co-registration, we estimate there is around a 0.4 mm discrepancy between lead position seen on 3DXT versus CT when corrected for brain shift. This is similar to that described in O-arm® or mobile CT series. For units where logistical or financial considerations preclude the acquisition of a cone beam CT or mobile CT scanner, our data support portable 3D C-arm fluoroscopy as an acceptable alternative with significantly lower radiation exposure.

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Background: Deep brain stimulation (DBS) is a highly efficient, evidence-based therapy to alleviate symptoms and improve quality of life in movement disorders such as Parkinson's disease, essential tremor, and dystonia, which is also being applied in several psychiatric disorders, such as obsessive-compulsive disorder and depression, when they are otherwise resistant to therapy.

Summary: At present, DBS is clinically applied in the so-called open-loop approach, with fixed stimulation parameters, irrespective of the patients' clinical state(s). This approach ignores the brain states or feedback from the central nervous system or peripheral recordings, thus potentially limiting its efficacy and inducing side effects by stimulation of the targeted networks below or above the therapeutic level.

Key messages: The currently emerging closed-loop (CL) approaches are designed to adapt stimulation parameters to the electrophysiological surrogates of disease symptoms and states. CL-DBS paves the way for adaptive personalized DBS protocols. This review elaborates on the perspectives of the CL technology and discusses its opportunities as well as its potential pitfalls for both clinical and research use in neuropsychiatric disorders.

Introduction: Anterior nucleus of the thalamus (ANT) deep brain stimulation (DBS) is an increasingly promising treatment option for refractory epilepsy. Optimal therapeutic benefit has been associated with stimulation at the junction of ANT and the mammillothalamic tract (mtt), but electrophysiologic markers of this target are lacking. The present study examined microelectrode recordings (MER) during DBS to identify unique electrophysiologic characteristics of ANT and the ANT-mtt junction.

Methods: Ten patients with medically refractory epilepsy underwent MER during ANT-DBS implantation under general anesthesia. MER locations were determined based on coregistration of preoperative MRI, postoperative CT, and a stereotactic atlas of the thalamus (Morel atlas). Several neurophysiological parameters including single unit spiking rate, bursting properties, theta and alpha power and cerebrospinal fluid (CSF)-normalized root mean square (NRMS) of multiunit activity were characterized at recording depths and compared to anatomic boundaries.

Results: From sixteen hemispheres, 485 recordings locations were collected from a mean of 30.3 (15.64 ± 5.0 mm) recording spans. Three-hundred and ninety-four of these recording locations were utilized further for analysis of spiking and bursting rates, after excluding recordings that were more than 8 mm above the putative ventral ANT border. The ANT region exhibited discernible features including: (1) mean spiking rate (7.52 Hz ± 6.9 Hz; one-way analysis of variance test, p = 0.014 when compared to mediodorsal nucleus of the thalamus [MD], mtt, and CSF), (2) the presence of bursting activity with 40% of ANT locations (N = 59) exhibited bursting versus 24% the mtt (χ2; p < 0.001), and 32% in the MD (p = 0.38), (3) CSF-NRMS, a proxy for neuronal density, exhibited well demarcated changes near the entry and exit of ANT (linear regression, R = -0.33, p < 0.001). Finally, in the ANT, both theta (4-8 Hz) and alpha band power (9-12 Hz) were negatively correlated with distance to the ventral ANT border (linear regression, p < 0.001 for both). The proportion of recordings with spiking and bursting activity was consistently highest 0-2 mm above the ventral ANT border with the mtt.

Conclusion: We observed several electrophysiological markers demarcating the ANT superior and inferior borders including multiple single cell and local field potential features. A local maximum in neural activity just above the ANT-mtt junction was consistent with the previously described optimal target for seizure reduction. These features may be useful for successful targeting of ANT-DBS for epilepsy.

Introduction: Colloid cysts often occur in the third ventricle, and they are considered benign, slowly growing lesions. They commonly present with symptoms of intracranial hypertension and rarely sudden death due to acute hydrocephalus. The management options include cerebrospinal fluid diversion procedure by shunt, endoscopic or transcranial surgical excision, and stereotactic aspiration. Complications associated with excisional procedures make them undesirable to some patients. Stereotactic radiosurgery has emerged as a noninvasive less risky treatment option. To date, there is no clinical series in the literature reporting on this treatment modality. The aim of the study was to determine the efficacy and safety of gamma knife (GK) radiosurgery in the treatment of third ventricular colloid cysts.

Methods: This is a retrospective study involving 13 patients with third ventricular colloid cysts who underwent GK radiosurgery. GK radiosurgery was used as a primary treatment in all the patients. The median prescription dose was 12 Gy (11-12 Gy). The cyst volumes ranged from 0.2 to 10 cc (median 1.6 cc).

Results: The median follow-up was 50 months (18-108 months). Cyst control was achieved in 100% of the patients. Complete or partial response was observed in 12 patients (92%). Eight patients (62%) had hydrocephalus on imaging at the initial diagnosis. Seven of these patients had VP shunt insertion before GK. One patient required shunt insertion after GK.

Conclusion: GK for third ventricular colloid cysts is a promising treatment, regarding its efficacy and safety, to be added to other treatment options. A longer follow-up is required to confirm long-term control.

Introduction: With recent advancements in deep brain stimulation (DBS), directional leads featuring segmented contacts have been introduced, allowing for targeted stimulation of specific brain regions. Given that manufacturers employ diverse markers for lead orientation, our investigation focuses on the adaptability of the 2017 techniques proposed by the Cologne research group for lead orientation determination.

Methods: We tailored the two separate 2D and 3D X-ray-based techniques published in 2017 and originally developed for C-shaped markers, to the dual-marker of the Medtronic SenSight™ lead. In a retrospective patient study, we evaluated their feasibility and consistency by comparing the degree of agreement between the two methods.

Results: The Bland-Altman plot showed favorable concordance without any noticeable systematic errors. The mean difference was 0.79°, with limits of agreement spanning from 21.4° to -19.8°. The algorithms demonstrated high reliability, evidenced by an intraclass correlation coefficient of 0.99 (p < 0.001).

Conclusion: The 2D and 3D algorithms, initially formulated for discerning the circular orientation of a C-shaped marker, were adapted to the marker of the Medtronic SenSight™ lead. Statistical analyses revealed a significant level of agreement between the two methods. Our findings highlight the adaptability of these algorithms to different markers, achievable through both low-dose intraoperative 2D X-ray imaging and standard CT imaging.

Introduction: Essential tremor (ET) is the most common movement disorder, characterized by an action tremor in the upper limbs. Neurosurgical techniques targeting the thalamic ventrointermediate nucleus (VIM) including thermocoagulation demonstrated a potential risk for gait and posture worsening. This study evaluates the potential effect of VIM Gamma Knife radiosurgery (GKR) in ET on gait and posture performances.

Methods: We conducted a prospective study to quantitatively assess gait and balance in severe ET patients before and 1 year after unilateral GKR. Seventy-three patients were included in this series.

Results: First, we confirmed the unilateral GKR efficacy in severe ET patients: global tremor score and impairments in activities of daily living improved, respectively, by 67% and 71.7%. The global gait and posture analysis found no significant differences before and 1 year after GKR. Three patients (4.1%) developed mild to moderate gait and posture impairment with proprioceptive ataxia. All of these AEs were induced by a hyper-response to radiosurgery.

Conclusions: Gait and posture performances were not statistically significant at the population. Nevertheless, gait and posture worsened in 4% of patients after GKR, all in the setting of hyper-response. This study shows that GKR may be a safe neurosurgical alternative to improve ADL in a population of patients with TE.

Introduction: Focused ultrasound (FUS) pallidotomy is a promising new therapy for Parkinson's disease (PD). The efficacy, motor outcomes, and side effects of FUS pallidotomy compared to radiofrequency (RF) pallidotomy are unknown.

Methods: We performed a systematic review of the outcomes and side effect profiles of FUS versus RF pallidotomy in patients with PD.

Results: Across four RF reports and one FUS report, putative contralateral UPDRS III scores were not significantly different following RF versus FUS pallidotomy. Across 18 RF and 2 FUS reports, the mean failure rate was 14% following RF pallidotomy versus 24% following FUS pallidotomy. Across 25 RF and 3 FUS reports, cognitive deficit was significantly more prevalent following RF pallidotomy (p = 0.004).

Conclusion: At present, limited data and heterogeneity in outcome reporting challenges comparisons of FUS and RF pallidotomy efficacy and safety. Available evidence suggests FUS pallidotomy may have broadly similar efficacy and a lower risk of cognitive impairment relative to RF pallidotomy. Standardized reporting of post-lesion outcomes in future studies would improve power and rule out potential confounders of these results.