Stereotactic and Functional Neurosurgery最新文献

Introduction: Meningiomas are the most common primary intracranial tumour. Gamma knife radiosurgery (GKRS) is a frequently employed non-invasive method of treatment, with good remission rates and low morbidity in literature. However, the role of GKRS in the management of "large" meningiomas is unclear, with reported outcomes that vary by centre. We aimed to assess the factors that influence long-term outcomes following GKRS in meningiomas >10 cc in volume.

Methods: A retrospectively analysed all patients with meningiomas exceeding 10 cc in volume who underwent GKRS between January 2006 and December 2021 at the National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru. Demographic, clinical, radiological, and follow-up data were acquired, and factors associated with progression following GKRS were assessed.

Results: The cohort comprised 76 patients 29 males (38.2%) and 47 females (61.8%) with a mean age of 46.3 ± 11.02 years. Thirty-nine patients had been previously operated (51.3%). Meningiomas were most frequently located in the parasagittal region (26 tumours, 34.2%) and sphenopetroclival region (23 tumours, 30.3%), with mean lesion volume of 12.55 ± 5.22 cc, ranging 10.3 cc-25 cc. The mean dose administered to the tumour margin was 12.5 Gy ± 1.2 Gy (range 6-15 Gy). The median duration of clinical follow-up was 48 months, over which period radiological progression occurred in 14 cases (20%), with unchanged tumour volume in 20 cases (28.6%) and reduction in size of the tumour in 36 cases (51.4%). Progression-free survival after GKRS was 72% at 5 years, was significantly poorer among meningiomas with tumour volume >14 cc (log-rank test p = 0.045), tumours presenting with limb motor deficits (log-rank test p = 0.012), and tumours that underwent prior Simpson grade 3 or 4 excision (log-rank test p = 0.032).

Conclusions: Meningiomas >10 cc in volume appear to display a high rate of progression and subsequent need for surgery following GKRS. Primary surgical resection, when not contraindicated, may be considered with GKRS serving an adjuvant role, especially in tumours exceeding 14 cc in volume, and presenting with limb motor deficits. Long-term clinical and radiological follow-up is essential following GKRS as the response of large meningiomas may be unpredictable.

Introduction: Deep brain stimulation (DBS) requires a consistent electrical supply from the implantable pulse generator (IPG). Patients may struggle to monitor their IPG, risking severe complications in battery failure. This review assesses current literature on DBS IPG battery life management and proposes a protocol for healthcare providers.

Methods: A literature search using four databases identified best practices for DBS IPG management. Studies were appraised for IPG management guidelines, categorized as qualitative, quantitative, or both.

Results: Of 408 citations, only seven studies were eligible, none providing clear patient management strategies. Current guidelines lack specificity, relying on clinician suggestions.

Conclusion: Limited guidelines exist for IPG management. Specificity and adaptability to emerging technology are crucial. The findings highlight the need for specificity in patients' needs and adaptability to emerging technology in future studies. To address this need, we developed a protocol for DBS IPG management that we have implemented at our own institution. Further research is needed for effective DBS IPG battery life management, preventing therapy cessation complications.

Introduction: L-2-hydroxyglutaric aciduria (L2HGA) is a rare neurometabolic disorder marked by progressive and debilitating psychomotor deficits. Here, we report the first patient with L2HGA-related refractory dystonia that was managed with deep brain stimulation to the bilateral globus pallidus internus (GPi-DBS).

Case presentation: We present a 17-year-old female with progressive decline in cognitive function, motor skills, and language ability which significantly impaired activities of daily living. Neurological exam revealed generalized dystonia, significant choreic movements in the upper extremities, slurred speech, bilateral dysmetria, and a wide-based gait. Brisk deep tendon reflexes, clonus, and bilateral Babinski signs were present. Urine 2-OH-glutaric acid level was significantly elevated. Brain MRI showed extensive supratentorial subcortical white matter signal abnormalities predominantly involving the U fibers and bilateral basal ganglia. Genetic testing identified a homozygous pathogenic mutation in the L-2-hydroxyglutarate dehydrogenase gene c. 164G>A (p. Gly55Asp). Following minimal response to pharmacotherapy, GPi-DBS was performed. Significant increases in mobility and decrease in dystonia were observed at 3 weeks, 6 months, and 12 months postoperatively.

Conclusion: This is the first utilization of DBS as treatment for L2HGA-related dystonia. The resulting significant improvements indicate that pallidal neuromodulation may be a viable option for pharmaco-resistant cases, and possibly in other secondary metabolic dystonias.

Introduction: Adoption of robotic techniques is increasing for neurosurgical applications. Common cranial applications include stereoelectroencephalography (sEEG) and deep brain stimulation (DBS). For surgeons to implement robotic techniques in these procedures, realistic learning curves must be anticipated for surgeons to overcome the challenges of integrating new techniques into surgical workflow. One such way of quantifying learning curves in surgery is cumulative sum (CUSUM) analysis.

Methods: Here, the authors present retrospective review of stereotactic cases to perform a CUSUM analysis of operative time for robotic cases at a single institution performed by 2 surgeons. The authors demonstrate learning phase durations of 20 and 16 cases in DBS and sEEG, respectively.

Results: After plateauing of operative time, mastery phases started at cases 132 and 72 in DBS and sEEG. A total of 273 cases (188 DBS and 85 sEEG) were included in the study. The authors observed a learning plateau concordant with change of location of surgery after exiting the learning phase.

Conclusion: This study demonstrates the learning curve of 2 stereotactic workflows when integrating robotics as well as being the first study to examine the robotic learning curve in DBS via CUSUM analysis. This work provides data on what surgeons may expect when integrating this technology into their practice for cranial applications.

Introduction: The aim of this study was to present a novel technique for subthalamic nucleus (STN) deep brain stimulation (DBS) implantation under general anesthesia by using intraoperative motor-evoked potentials (MEPs) through direct lead stimulation and determining their correlation to the thresholds of postoperative stimulation-induced side effects.

Methods: This study included 22 consecutive patients with advanced Parkinson's disease who underwent surgery in our institution between January 2021 and September 2023. All patients underwent bilateral implantation in the STN (44 leads) under general anesthesia without microelectrode recordings (MERs) by using MEPs with electrostimulation directly through the DBS lead. No cortical stimulation was performed during this process. Intraoperative fluoroscopic guidance and immediate postoperative computed tomography were used to verify the electrode's position. The lowest MEP thresholds were recorded and were correlated to the postoperative stimulation-induced side-effect threshold. The predictive values of the MEPs were analyzed. Five DBS leads were repositioned intraoperatively due to the MEP results.

Results: A moderately strong positive correlation was found between the MEP threshold and the capsular side-effect threshold (RS = 0.425, 95% CI, 0.17-0.67, p = 0.004). The highest sensitivity and specificity for predicting a side-effect threshold of 5 mA were found to be at 2.4 mA MEP threshold (sensitivity 97%, specificity 87.5%, positive predictive value 97%, and negative predictive value 87.5%). We also found high sensitivity and specificity (100%) at 1.15 mA MEP threshold and 3 mA side-effect threshold. Out of the total 44 leads, 5 (11.3%) leads were repositioned intraoperatively due to MEP thresholds lower than 1 mA (4 leads) or higher than 5 mA (1 lead). The mean accuracy on postoperative CT was 1.05 mm, and there were no postoperative side-effects under 2.8 mA.

Conclusion: Intraoperative MEPs with electrostimulation directly through the contacts of the DBS lead correlate with the stimulation-induced capsular side effects. The lead reposition based on intraoperative MEP may enlarge the therapeutic window of DBS stimulation.

Introduction: Hemispheric surgery is a multistep, highly effective, and radical surgical procedure in the treatment of drug-resistant epilepsy due to extensive unilateral hemispheric disease. The procedure ranges from a resective procedure (hemispherectomy) to disconnection (hemispherotomy) and has developed substantially over the last century from morbid to elegant, minimally invasive, and routinely practiced procedures. Bearing in mind the numerous articles that have been published on hemispherectomy and hemispherotomy, we aimed to highlight the top 100 cited and impactful articles to create familiarity with the topic. We anticipate that this will be a helpful guide for clinicians and academics navigating the literature on this subject.

Methods: A Scopus title-based search on the top 100 most-cited articles on "hemispherectomy" and "hemispherotomy" was performed in September 2023 with no restrictions. The top 100 most-cited articles were then retrieved. The article title, first author, first author's specialty, country of origin, first author's institution at the time of publication, journal of publication, year of publication, citation count, and citations per year were collected. The Google Scholar database citation count for each paper was added for correlation and comprehensive coverage.

Results: The top 100 most-cited articles were cited 92 times per paper on average. The publication dates ranged from 1949 to 2016. The most frequently cited article "Clinical outcomes of hemispherectomy for epilepsy in childhood and adolescence" with 307 citations was published by A.M. Devlin et al. (2003) in the journal Brain. The USA was the highest publishing country (41 articles). The highest-publishing journal was Neurology. The most prolific first authors were A. Smith, J. Schramm, and J. Villemure, each with four publications. The institution with the most contributions was McGill University and its affiliated Health Centers, with nine publications in total. Neurosurgery was the most common specialty among the first authors. Most of the included studies were cohort studies or case series.

Conclusion: We identified the top 100 cited articles on hemispherectomy and hemispherotomy using the Scopus database and supplemented our results with Google Scholar. We highlighted the most prominent authors, institutions, countries, journals, and study designs and illuminated the historical development of hemispherectomy and hemispherotomy procedures, in addition to landmark and currently trending papers.

Introduction: Deep brain stimulation (DBS) is a routine neurosurgical procedure utilized to treat various movement disorders including Parkinson's disease (PD), essential tremor (ET), and dystonia. Treatment efficacy is dependent on stereotactic accuracy of lead placement into the deep brain target of interest. However, brain shift attributed to pneumocephalus can introduce unpredictable inaccuracies during DBS lead placement. This study aimed to determine whether intracranial air is associated with brain shift in patients undergoing staged DBS surgery.

Methods: We retrospectively evaluated 46 patients who underwent staged DBS surgery for PD, ET, and dystonia. Due to the staged nature of DBS surgery at our institution, the first electrode placement is used as a concrete fiducial marker for movement in the target location. Postoperative computed tomography (CT) images after the first electrode implantation, as well as preoperative, and postoperative CT images after the second electrode implantation were collected. Images were analyzed in stereotactic targeting software (BrainLab); intracranial air was manually segmented, and electrode shift was measured in the x, y, and z plane, as well as a Euclidian distance on each set of merged CT scans. A Pearson correlation analysis was used to determine the relationship between intracranial air and brain shift, and student's t test was used to compare means between patients with and without radiographic evidence of intracranial air.

Results: Thirty-six patients had pneumocephalus after the first electrode implantation, while 35 had pneumocephalus after the second electrode implantation. Accumulation of intracranial air following the first electrode implantation (4.49 ± 6.05 cm3) was significantly correlated with brain shift along the y axis (0.04 ± 0.35 mm; r (34) = 0.36; p = 0.03), as well as the Euclidean distance of deviation (0.57 ± 0.33 mm; r (34) = 0.33; p = 0.05) indicating statistically significant shift on the ipsilateral side. However, there was no significant correlation between intracranial air and brain shift following the second electrode implantation, suggesting contralateral shift is minimal. Furthermore, there was no significant difference in brain shift between patients with and without radiographic evidence of intracranial air following both electrode implantation surgeries.

Conclusion: Despite observing volumes as high as 22.0 cm3 in patients with radiographic evidence of pneumocephalus, there was no significant difference in brain shift when compared to patients without pneumocephalus. Furthermore, the mean magnitude of brain shift was <1.0 mm regardless of whether pneumocephalus was presenting, suggesting that intracranial air accumulation may not produce clinical significant brain shift in our patients.

Introduction: MRI-guided focused ultrasound (FUS) is an incisionless thermo-ablative procedure that may be used to treat medication-refractory movement disorders, with a growing number of potential anatomic targets and clinical applications. As of this article's publication, the only US Food and Drug Administration (FDA)-approved uses of FUS for movement disorders are thalamotomy for essential tremor (ET) and tremor-dominant Parkinson's Disease (PD), and pallidotomy for other cardinal symptoms of PD. We present a state-of-the-art review on all non-FDA approved indications of FUS for movement disorders, beyond the most well-described indications of ET and PD. Our objective was to summarize the safety and efficacy of FUS in this setting and provide a roadmap for future directions of FUS for movement disorders.

Methods: A state-of-the-art review was conducted on use of FUS for non-FDA approved movement disorders. All movement disorders excluding FDA-approved uses for ET and PD were included.

Results: A total of 25 studies on 172 patients were included. In patients with tremor plus dystonia syndromes (n = 6), ventralis intermediate nucleus of the thalamus (VIM)-FUS gave >50% tremor reduction, with no improvement in dystonia and worsened dystonia in 2/6 patients. Ventral-oralis complex (VO)-FUS gave >50% improvement for focal hand dystonia (n = 6) and 100% return to musical performance in musician's dystonia (n = 6). In patients with multiple sclerosis (MS) and tremor (n = 3), improvement in tremor was seen in 2 patients with a favorable skull density ratio; no MS disease change was noted after VIM-FUS. In patients with tremor and comorbid ataxia syndromes (n = 3), none were found to have worsened ataxia after VIM-FUS; all had clinically significant tremor improvement. Subthalamic nucleus (STN)-FUS for PD (n = 49) gave approximately 50% improvement in PD motor symptoms, with dystonia and mild dyskinesias as possible adverse effects. Cerebellothalamic tract (CTT-FUS) for ET (n = 42) gave 55-90% tremor improvement, with gait dysfunction as a rare persistent adverse effect. Pallidothalamic tract (PTT-FUS) for PD (n = 50) gave approximately 50% improvement in motor symptoms, with mild speech dysfunction as a possible adverse effect.

Conclusion: VIM-FUS appeared safe and effective for heterogenous tremor etiologies, and VO-FUS appeared most effective for isolated segmental dystonia. STN-FUS was effective for PD symptom reduction; postoperative dystonia and mild on-medication dyskinesias required medical management. Tractography-based targeting with CTT-FUS for ET and PTT-FUS for PD demonstrated promising early results. Larger prospective trials with long-term follow-up are needed to the evaluate the safety and efficacy non-FDA approved indications for FUS.

Introduction: This study aimed to assess the impact of gamma knife radiosurgery on brainstem cavernous malformations (CMs).

Methods: A total of 85 patients (35 females; median age 41.0 years) who underwent gamma knife radiosurgery for brainstem CMs at our institute between 2006 and 2015 were enrolled in a prospective clinical observation trial. Risk factors for hemorrhagic outcomes were evaluated, and outcomes were compared across different margin doses.

Results: The pre-radiosurgery annual hemorrhage rate (AHR) was 32.3% (44 hemorrhages during 136.2 patient-years). The median planning target volume was 1.292 cc. The median margin and maximum doses were 15.0 and 29.2 Gy, respectively, with a median isodose line of 50.0%. The post-radiosurgery AHR was 2.7% (21 hemorrhages during 769.9 patient-years), with a rate of 5.5% within the first 2 years and 2.0% thereafter. The post-radiosurgery AHR for patients with margin doses of ≤13.0 Gy (n = 15), 14.0-15.0 Gy (n = 50), and ≥16.0 Gy (n = 20) was 5.4, 2.7, and 0.6%, respectively. Correspondingly, transient adverse radiation effects were observed in 6.7 (1/15), 10.0 (5/50), and 30.0% (6/20) of cases, respectively. An increased margin dose per 1 Gy (hazard ratio: 0.530, 95% CI: 0.341-0.826, p = 0.005) was identified as an independent protective factor against post-radiosurgery hemorrhage. Margin doses of ≥16.0 Gy were associated with improved hemorrhagic outcomes (hazard ratio: 0.343, 95% confidence interval [CI]: 0.157-0.749, p = 0.007), but an increased risk of adverse radiation effects (odds ratio: 3.006, 95% CI: 1.041-8.677, p = 0.042).

Conclusion: The AHR of brainstem CMs decreased following radiosurgery, and our study revealed a significant dose-response relationship. Margin doses of 14-15 Gy were recommended. Further studies are required to validate our findings.