Stereotactic and Functional Neurosurgery最新文献

Introduction: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy effectively treats medication-resistant essential tremor (ET). Usually, intracranial calcifications are excluded as no-pass zones because of their low penetrability which may limit the effectiveness of treatment and lead to unintended side effects. This case report illustrates the efficacy of unilateral MRgFUS for tremor control in a patient with extensive basal ganglia calcifications due to Fahr's disease.

Case presentation: A 69-year-old right-handed male with debilitating Fahn-Tolosa-Marin grade 3-4 bilateral hand tremor underwent unilateral left MRgFUS thalamotomy. The treatment involved careful preoperative planning to accommodate his extensive basal ganglia calcifications, element path consideration, and skull density ratio to ensure accurate and effective lesioning. Posttreatment, the patient exhibited complete abolition of tremor on the treated side with minor transient dysarthria and imbalance. Follow-up at 12 weeks posttreatment showed sustained tremor relief and an absence of any adverse effects, validating the procedural adjustments made to accommodate the unique challenges posed by his intracranial calcifications.

Conclusion: MRgFUS can be safely and effectively applied in certain patients with extensive basal ganglia calcifications - in this case, due to Fahr's disease. This case report suggests expanding the application of MRgFUS to patients with extensive intracranial calcifications who previously might not have been considered suitable candidates for MRgFUS.

Introduction: Postherpetic neuralgia (PHN) is a pain syndrome that develops within few months after the acute herpetic outbreak. The pain may be accompanied by specific cutaneous signs in the distribution of affected dermatomes and feel unbearable reaching up to 9-10/10 on visual analog scale (VAS). Despite the introduction of new medications, drug resistance develops in at least 50% of cases. Neuromodulation techniques such as spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS) are considered as ones of the last resorts for PHN treatment, especially in pharmacoresistant patients. Recently, several studies with limited number of cases have shown high efficiency of neuromodulation (regression of pain syndrome in more than 82% of cases) after SCS in PHN patients, but these findings require further confirmation and have not been supported by large RCTs.

Methods: Initially, 32 patients diagnosed with chronic drug-resistant PHN underwent a trial of SCS. Based on the trial results, a decision was made whether to implant a permanent SCS system. The condition of all patients implanted with SCS system was assessed using the VAS, SF-36, Patient Global Impression of Change (PGIC), and Medicine Quantification Scale, version III (MQS) questionnaires before the surgery and in the long-term follow-up. We also conducted systematic follow-up of patients who did not pass the test stimulation stage, using them as a control group to track the levels of pain. The hypothesis of normal distribution for quantitative values was tested using Shapiro-Wilk tests.

Results: During the trial period, tonic spinal stimulation was effective in 16 out of 32 (50%) patients with drug-resistant PHN. Among 14 patients with implanted stimulators, a significant pain reduction (more than 50% from the baseline) was observed in 10 patients (71.4%). The pain level in patients with a tonic SCS was statistically lower than in patients receiving conservative therapy. For the entire group of patients with implanted SCS, a significant improvement was also observed in results of SF-36, PGIC, and MQS.

Conclusion: Our clinical series demonstrates that tonic SCS was effective in 50% of patients with refractory PHN undergoing SCS trial. Significant improvement in pain control obtained during the long-term follow-up in patients treated with tonic SCS improves the quality of life and reduces the need for analgesic medications.

Introduction: One of the challenges in directional deep brain stimulation (DBS) is to determine the orientation of implanted electrodes relative to targeted regions. Post-operative images must be aligned with a model of the implanted lead, usually a computer-based model provided by the manufacturer. This paper shows that models can alternatively be obtained by capturing images of individual leads using micro-CT, a high-resolution CT technique. Contrary to computer-aided design models, lead models generated this way provide realistic X-ray contrast and finer details.

Methods: We scanned DBS leads from various vendors using a Bruker SkyScan 1276 micro-CT system. To reduce beam-hardening artefacts, samples were scanned at maximum X-ray tube voltage (100 kV) and with copper filtering. Images were made publicly available for download and 3D visualisation.

Conclusion: Detailed images of single DBS leads can be generated using standard micro-CT systems. Their use as reference models could improve lead orientation algorithms, in particular those dedicated to X-ray modalities. Furthermore, the possibility to share models online could broaden access for clinical research.

Introduction: Spinal cord stimulation (SCS) is an effective treatment for patients with refractory chronic pain. Despite its efficacy, rates of reoperation after initial implantation of SCS remain high. While revision rates after index SCS surgeries are well reported, less is known about rates and risk factors associated with repeat reoperations. We sought to evaluate patient, clinical, and surgical characteristics associated with repeat reoperation among patients who underwent an initial SCS revision procedure.

Methods: We performed a retrospective review of patients who underwent SCS revision surgery performed at a single institution between 2008 and 2022. Patients were stratified by whether they underwent a single revision (SR) or multiple revision (MR) surgeries. Multivariate logistic regression was performed to determine risk factors associated with repeat SCS revision. Kaplan-Meier survival analysis was used to compare rates of devices requiring revision across groups.

Results: A total of 54 patients underwent an initial SCS revision. Of these, 15 (28%) underwent a second revision. The most common indication for revision surgery was lead migration (65%). No significant differences were observed in age, body mass index, comorbidities, lead type, and revision indication among the SR and MR groups. On multivariate adjusted analysis, only cervical lead position was significantly associated with repeat reoperation (OR 7.10, 95% CI [1.14, 44.3], p = 0.036). Time to reoperation after a single and MR SCS surgeries did not differ.

Conclusions: Among patients who undergo SCS reoperation, a substantial portion requires additional revisions. Cervical lead placement may be associated with a higher risk of repeat revision surgery compared to thoracic lead positioning. Consideration of lead positioning in the decision to perform and undergo reoperation may therefore result in lower revision rates and improved clinical outcomes among SCS patients with MRs.

Introduction: Cerebellar deep brain stimulation (DBS) is gaining traction as a potential treatment for movement disorders and stroke, and there is renewed interest in the cerebellum as a target for neuromodulation. Despite the safety and accuracy of frame-based approaches to the posterior fossa, unconventional stereotactic frame placement may be necessary to allow for low posterior fossa trajectories. Current literature lacks a comprehensive protocol detailing inverted frame placement and targeting.

Methods: Preoperative imaging was acquired prone. An inverted Leksell G frame was applied along with an open-topped CT fiducial box, followed by a prone CT with the scanner set to the "legs first, nose up" configuration. Target coordinates were extracted from navigation software after image fusion. Intraoperatively, the patient was positioned prone, and the stereotactic arc was mounted in the lateral-right orientation, with inverted arc supports. Confirmatory stereotaxy to a scalp staple was performed, and the DBS leads were then inserted.

Conclusion: Our standardized protocol provides a flexible platform for posterior fossa DBS, allowing for low trajectories and multiple electrodes. Unlike conventional upright frame placement, an inverted frame permits an unobstructed view of suboccipital entry sites and incision placement. A conventional frame and regular planning software are sufficient, with no additional mathematical calculations required.

Introduction: Rising NHS waiting lists are a major problem following the COVID-19 pandemic. In our institution, surgical waiting time for elective functional neurosurgical procedures, such as deep brain stimulation (DBS) and radiofrequency ablation (RFA), reached >1.5 years by the end of 2022. During 2023, reduced operating room availability, intraoperative MRI (iMRI) suite closure for refurbishment, and ongoing strikes threatened to increase waiting times further.

Methods: Our previous surgical workflow for DBS and RFA procedures was examined. Several aspects were identified, and changes implemented to increase efficiency. Procedure numbers, waiting times, lead placement accuracy, and complication rates before and after these changes were compared.

Results: Prior to 2023, an average of 0.8 new procedures were performed per surgical list. Introduction of a new workflow in 2023 allowed an average of 1.6 new procedures per surgical list (100% increase in productivity). In 2023, 95 DBS and 31 RFA procedures were performed on 79 surgical lists. This represents a 52% increase over "pre-pandemic" activity in 2019 (74 DBS, 9 RFA) on 102 available surgical lists. Mean (SD) targeting accuracy (0.8 [0.4] mm) was comparable to previous years (0.9[0.3] mm). In 2023, there were no infections requiring hardware removal and only one asymptomatic haemorrhage following an RFA procedure. The surgical waiting time was reduced from >1.5 years to <4 months by the end of 2023.

Conclusion: Changes in surgical workflow, with neurosurgeons working in parallel, maximise surgical efficiency and productivity, significantly increasing the number of DBS and RFA procedures without compromising accuracy and safety.

Introduction: Direct targeting in deep brain stimulation (DBS) has remarkably impacted the patient's experience throughout the surgery and the overall logistics of the procedure. When the individualised plan is co-registered with a 3D image acquired intraoperatively, the electrodes can be safely placed under general anaesthesia. How this applies to a general practice scenery (outside clinical trials and in a moderate caseload centre) has been scarcely reported.

Methods: Prospective single-centre study of patients treated with asleep subthalamic DBS for Parkinson's disease between January 2021 and December 2022. Clinical, motor, medication-dependence, and quality-of-life outcomes were evaluated after optimal programming (6 months). Wilcoxon test was used to compare pre- versus post-repeated measures. Surgical-related parameters were also analysed.

Results: Eighty-nine patients primarily operated for DBS were included in the study. Intraoperative electrode replacement was not necessary. Mean surgical duration was 217 (SD 44) minutes, including the implantation of the generator; and mean length of stay was 3 (SD 1) days. There was one surgical-related complication (delayed infection). Significant and clinically relevant improvement was seen in UPRS III (mean decrease 62%) (p < 0.001) and PDQ-8 (50% increase) (p < 0.001) after 6 months. Daily doses of medication were decreased by a mean of 68%, p < 0.001).

Conclusion: DBS can be safely performed under general anaesthesia in a pragmatic clinical environment, provided a multidisciplinary committee for patient selection and a dedicated surgical and anaesthetic team are available. The effectiveness in ameliorating motor symptoms, the ability to reduce the drug load, and the improvement in quality of life demonstrated in clinical trials could be reproduced under more generalised conditions as in our centre. The need for a team learning curve and the progressive evolution in, and adaptation to, trajectory planning software, anaesthetic management, intraoperative imaging, DBS device upgrades, and programming schemes should be contemplated in the transition process to direct targeting.

Introduction: Freezing of gait (FOG) is a clinical phenomenon with major life impairments and significant reduction in quality of life for affected patients. FOG is a feature of Parkinson's disease and a hallmark of primary progressive FOG, currently reclassified as Progressive Supranuclear Palsy-progressive gait freezing (PSP-PGF). The pathophysiology of FOG and particularly PGF, which is a rare degenerative disorder with a progressive natural history of gait decline, is poorly understood. Mechanistically, changes in oscillatory activity and synchronization in frontal cortical regions, the basal ganglia, and the midbrain locomotor region have been reported, indicating that dysrhythmic oscillations and coherence could play a causal role in the pathophysiology of FOG. Deep brain stimulation and spinal cord stimulation (SCS) have been tested as therapeutic neuromodulation avenues for FOG with mixed outcomes.

Methods: We analyzed gait and balance in 3 patients with PSP-PGF who received percutaneous thoracic SCS and utilized magnetoencephalography (MEG), electroencephalography, and electromyography to evaluate functional connectivity between the brain and spine.

Results: Gait and balance did not worsen over a 13-month period. This observation was accompanied by decreased beta-band spectral power in the whole brain and particularly in the basal ganglia. This was accompanied by increased functional connectivity in and between the sensorimotor cortices, basal ganglia, temporal cortex, and cerebellum, and a surge in corticomuscular coherence when SCS was paired with visual cues.

Conclusion: Our results suggest synergistic activity between brain and spinal circuits upon SCS for FOG in PGF, which may have implications for future brain-spine interfaces and closed-loop neuromodulation for patients with FOG.