A Comprehensive Training Model for Simulation of Intracranial Aneurysm Surgery Using a Human Placenta and a Cadaveric Head.

BACKGROUND AND OBJECTIVES: Aneurysmal surgery is technically complex, and surgeon experience is an important factor in therapeutic success, but training young vascular neurosurgeons has become a complex paradigm. Despite new technologies and simulation models, cadaveric studies still offer an incomparable training tool with perfect anatomic accuracy, especially in neurosurgery. The use of human placenta for learning and improving microsurgical skills has been previously described. In this article, we present a comprehensive simulation model with both realistic craniotomy exposure and vascular handling consisting of a previously prepared and perfused human placenta encased in a human cadaveric specimen. METHODS: Humans' placentas from the maternity and cadaveric heads from the body donation program of the anatomy laboratory were used. Placentas were prepared according to the established protocol, and aneurysms were created by catheterization of a placental artery. Ten participants, including senior residents or young attendees, completed an evaluation questionnaire after completing the simulation of conventional unruptured middle artery aneurysm clipping surgery from opening to closure. RESULTS: The skin incision, muscle dissection, and craniotomy were assessed as very similar to reality. Brain tissue emulation and dissection of the lateral fissure were judged to be less realistic. Vascular management was evaluated as similar to reality as closure. Participants uniformly agreed that this method could be implemented as a standard part of their training. CONCLUSION: This model could provide a good model for unruptured aneurysm clipping training.

Adolescents and Young Adults with Primary Brain Tumor: Description of the Care Pathway of Patients Diagnosed in Grenoble Between 2013 and 2019.

Purpose: This study was undertaken to describe the Adolescents and Young Adults' (AYA-aged patients') neuro-oncology care pathways at Grenoble Alpes University Hospital according to the French health recommendations. Methods: A retrospective monocentric observational study was conducted between 2020 and 2021, on patients 13-29 years of age, diagnosed from January 2013 to 2019 in our institute with a primary brain tumor, excluding meningiomas, schwannomas, and neurinomas. The detailed analysis took into account the type of care unit (adult or pediatric), whether or not a dedicated AYA support team was involved, and various pretherapeutic actions. Results: Sixty patients were included in this study. Three of the 9 key stages of the care process were completed regardless of the type of management. Management in a pediatric oncology department seems to improve multidisciplinary discussions and access to the AYA team. Collaboration with an AYA team seems to improve the recourse to pediatric advice and supportive care. Conclusions: Increased vigilance at all key steps as defined in the recommendations of the Directorate General of Healthcare Services would significantly improve the overall quality of care for this specific population. In the absence of a dedicated AYA hospitalization unit, interdisciplinary cooperation between the different professionals of the adult and pediatric services is essential, and the involvement of the AYA mobile team is a factor that favors links and exchanges and ultimately an overall improvement in patient care and life. We propose our vision of an ideal AYA neuro-oncology care pathway.

Mechanical Complications of Sophysa SM8 Shunt in Adult Hydrocephalus: A Monocentric Experience.

BACKGROUND: Sophysa SM8 is widely used by neurosurgeons in France. Published studies report shunt malfunction rates in adults between 18% and 29%. However, these studies included multiple valve types and thus entailed a serious confounding factor. OBJECTIVE: To ascertain the incidence the Sophysa SM8 cerebrospinal fluid (CSF) shunt malfunctions in adults. METHODS: We present a retrospective series of adult patients who underwent CSF shunt placement between 2000 and 2013 with Sophysa SM8. RESULTS: In total, 599 patients (329 males and 270 females) were included. The mean age at surgery was 64.15 years (19-90) (SD 16.17; median 68.0). The causes of hydrocephalus were normal pressure hydrocephalus (49%), traumatic hemorrhages (26.5%), tumors (15.7%), cerebral aqueduct stenoses (3%), and arachnoid cysts (2%). The mean follow-up was 3.9 years (0-16) (SD 4.10; median 3 years). The rate of complications was 22.04% (132 of 599). Most frequent causes of complications were disconnection (25%), migration (12.9%), overdrainage (9.1%), and proximal obstruction (6.8%). In 17 cases (12.9%), no failure was diagnosed during revision. Seven infections (5.3%) were reported. The mean delay for the first revision was 1.70 years (0-13.93) (SD 2.67, median 0.35). The risk of shunt failure was 36% at 10 years. Seventeen percent of revisions occurred during the first year after shunt placement. CONCLUSION: Disconnections are a very frequent complication of Sophysa SM8 valve. They are related to the 2-connector system of this valve. Based on these results, we recommend using 1-piece valves.

Variability of Intraoperative Electrostimulation Parameters in Conscious Individuals: Language Fasciculi.

OBJECTIVE: The authors analyzed the current-intensity thresholds for electrostimulation of language fasciculi and the possible consequences of threshold variability on brain mapping. METHODS: A prospective protocol of subcortical electrostimulation was used in 50 patients undergoing brain mapping, directly stimulating presumed language fasciculi identified by diffusion tensor imaging. RESULTS: The stimulation-intensity thresholds for identification of language fasciculi varied among patients (mean minimum current intensity of 4.4 mA, range = 1.5-10 mA, standard deviation = 1.1 mA), and 23% of fascicular interferences were detected only above 5 mA. Repeated stimulation of the same site with the same intensity led to different types of interferences in 20% of patients, and a higher current intensity led to changes in the type of response in 27%. The mean minimum stimulation intensities did not differ significantly between different fasciculi, between the different types of interference obtained, or with age, sex, or type of tumor. Positive results on cortical mapping were significantly associated with positive results on subcortical mapping (P < 0.001). Subcortical intensity thresholds were slightly lower than cortical ones (mean = 4.43 vs. 5.25 mA, P = 0.034). In 23 of 50 subcortical mappings, fascicular stimulation produced no language interference. CONCLUSIONS: Individual variability of minimum stimulation-intensity thresholds for identification of language fasciculi is frequent. Nevertheless, even when a high current intensity was used, many stimulations on language fasciculi remained negative for various hypothetic reasons. Finding the optimal current intensity for identifying language fasciculi is of paramount importance to refine the clinical results and scientific data derived from brain mapping.

Mechanical complications of cerebrospinal fluid shunt. Differences between adult and pediatric populations: myths or reality?

OBJECTIVE: Shunt malfunctions seem more frequent in children (44 to 81%) than in adults (18 to 29%). Because of discrepancies between studies, it is not possible to affirm this disparity. The objective was to verify whether the incidence of cerebrospinal fluid (CSF) shunt malfunctions is higher in children than adults. METHODS: We present a retrospective series of child and adult patients who underwent CSF shunt placement between 2000 and 2013 with a Sophysa SM8® valve. RESULTS: 599 adults and 98 children (sex ratio 1.28) underwent CSF shunt placement. Age at first surgery ranged between 1 day of life and 90 years (mean of 55.8 years, SD 25.8, median 64.8 years). The mean follow-up was 4 years (SD 4.264, 0-16; median 3 years). The cumulative complication rate was 25.5% (178/697). Mechanical complications were disconnection (25.1%), migration (11.8%), intracranial catheter obstruction (8.9%) and malposition (8.4%). The mean delay for the first revision was 1.90 years (0-13.9), (SD 2.73, median 0.5). The probability of shunt failure was 65% at 10 years in the child group and 36% at 10 years in the adult group. Moreover, in the child group, 33% of revisions occurred during the first year after shunt placement versus 17% in the adult group. Thus, the probability of shunt failure was higher in children than in adults (log-rank test, p < 0.001). CONCLUSIONS: This is the first retrospective study, comparing children and adults undergoing CSF shunt using the same valve, able to confirm the higher rate of complications in children.

Rate of Rebleed and Retreatment of Previously Treated Intracranial Aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) can be treated through endovascular treatment (EVT) or microsurgery (MS). Treated IAs can recanalize, which can lead to rupture or retreatment. OBJECTIVE: The aim of our study was to evaluate the natural history of previously treated IA, by evaluating the risk of rupture and the risk of retreatment. METHODS: All patients treated for an IA between 2007 and 2017 in 4 hospitals were included. The rate of (recurrent) hemorrhage and the rate of prophylactic retreatment were retrospectively evaluated. Kaplan-Meier survival analysis with log-rank tests was used to compare the rates of rupture or retreatment. Patients with ruptured and unruptured aneurysms were separated, and we compared the risk of retreatment between EVT and the surgical treatment. RESULTS: A total of 4997 IAs were included in the study, corresponding to 20,489 patient-years. Overall, 28 (0.6%) aneurysms that had been previously treated demonstrated hemorrhage. Moreover, 237 (4.7%) aneurysms were retreated for recanalization without hemorrhage. The rate of retreatment was higher in the EVT-treated IAs as compared with the MS-treated IAs (LogRank: P < 0.0001) and higher in the previously ruptured IAs versus unruptured IAs (LogRank: P < 0.0001). However, the rate of posttreatment hemorrhage/IA rupture was similar for both groups. CONCLUSIONS: The rate of IA retreatment is low; however, the rate of hemorrhage/rupture from treated IAs is even lower. A higher rate of retreatment was noted in EVT-treated IAs versus MS-treated IAs and in ruptured IAs versus unruptured IAs; however, the rate of hemorrhage or rerupture was comparable between the groups.

Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part II: Success of Multiple Fenestrations: Two-Dimensional Operative Video.

Premature infants with severe germinal matrix/intraventricular hemorrhage are at high risk of posthemorrhagic ventricular dilation and hydrocephalus (Video 1). We report a 4-month-old premature infant with grade III intraventricular hemorrhage and compartmentalized hydrocephalus with an unusual craniospinal cyst. The cyst extended anteriorly from the mesencephalon to the posterior wall of C6, causing severe compression of the brainstem and spinal cord. An endoscopic procedure was performed first to achieve a unique cranial fenestration, which is detailed in "Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part I: Failure of Unique Fenestration." One month later the clinical picture recurred. Magnetic resonance imaging revealed hydrocephalus and cyst recurrence. A second procedure with endoscopic fenestration and shunt revision was needed. The same right transfontanellar approach was chosen, using a straight 30° endoscope. The procedure and surgical technique are explained in a step-by-step fashion. Extreme care was taken to align the head and the cervical spine. This allowed access to the extreme caudal cyst membrane posterior to C6 to create multiple transfixing fenestrations of the cyst. At 18-month follow-up, the child demonstrated almost normal neurological and psychomotor development with no cyst recurrence or hydrocephalus. Our report underlines the importance of performing multiple fenestrations of such cysts. We believe that performing a transfixing fenestration through the cyst allows cerebrospinal fluid flow and prevents recurrence, as, for instance, has been shown for suprasellar arachnoid cysts.

Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part I: Failure of Unique Fenestration: 2-Dimensional Operative Video.

Premature infants with severe germinal matrix intraventricular hemorrhage (IVH) are at high risk of posthemorrhagic ventricular dilation and hydrocephalus (Video 1). We report the case of a 3-month-old premature infant referred for posthemorrhagic multilocated hydrocephalus. He presented with somnolence, hypotonia, and a bulging fontanelle. His past medical history included an IVH grade III with hydrocephalus initially treated by temporary ventriculosubgaleal shunting. Magnetic resonance imaging (MRI) showed persistent hydrocephalus associated to a cyst extending anteriorly from the mesencephalon to the posterior wall of the sixth cervical vertebra, causing severe brainstem and spinal cord compression. A two-step surgery was performed, consisting of an endoscopic procedure and a ventriculo peritoneal shunt placement, to achieve hydrocephalus treatment and cyst fenestration. A right transfontanellar approach with the head flexed was chosen, using a straight 30-degree endoscope. The procedure and surgical technique are explained in a step-by-step fashion in the original conditions. A large unique fenestration was performed with no postoperative complications and improvement of the neurological status. One month later the patient presented again with symptomatic intracranial hypertension with compatible clinical and imagery findings. MRI showed cyst recurrence and hydrocephalus. We therefore revised our strategy and performed an additional procedure, which is detailed in the second part of the video (Part II: Success of Multiple Fenestrations). Our report underlines the high risk of recurrence of such cysts in post-hemorrhagic arachnoiditis. Cyst recurrence may be explained by the absence of crossing flow when a unique perforation is made.

Using Smartphones for Clinical Assessment in Cervical Spondylotic Myelopathy a Feasibility Study.

Degenerative cervical myelopathy (DCM) is characterized by a progressive deterioration in spinal cord function. Its evaluation requires subjective clinical examination with wide interobserver variability. Objective quantification of spinal cord function remains imprecise, even though validated myelopathy-grading scales have emerged and are now widely used. We created a Smartphone Application, the N-Outcome App, with the aim of quantifying accurately and reliably spinal cord dysfunction using a 5-minute Test. A patient suffering from DCM was clinically evaluated before surgery, at 3 and 6 months follow-up after surgical decompression of the cervical spinal cord. Standard scores (Nurick grade, modified Japanese Orthopedic Association (mJOA) score) were documented at these time points. A 5-minute motor and proprioceptive performance test aided by a smartphone with the N-outcome App was also performed. Motor performance in rapid alternating movements and finger tapping improved in correlation with improvements in standard grading scale scores. Clinical improvements were seen in maximum reflex acceleration and in Romberg testing which showed less closed/open eyes variation, suggesting pyramidal and proprioceptive function recovery. We demonstrate that using the N-Outcome App as an adjunct to clinical evaluation of compressive myelopathy is feasible and potentially useful. The results correlate with the results of clinical assessment obtained by standard validated myelopathy scores.

Indications, Techniques, and Outcomes of Robot-Assisted Insular Stereo-Electro-Encephalography: A Review.

Stereo-electro-encephalography (SEEG) is an invasive, surgical, and electrophysiological method for three-dimensional registration and mapping of seizure activity in drug-resistant epilepsy. It allows the accurate analysis of spatio-temporal seizure activity by multiple intraparenchymal depth electrodes. The technique requires rigorous non-invasive pre-SEEG evaluation (clinical, video-EEG, and neuroimaging investigations) in order to plan the insertion of the SEEG electrodes with minimal risk and maximal recording accuracy. The resulting recordings are used to precisely define the surgical limits of resection of the epileptogenic zone in relation to adjacent eloquent structures. Since the initial description of the technique by Talairach and Bancaud in the 1950's, several techniques of electrode insertion have been used with accuracy and relatively few complications. In the last decade, robot-assisted surgery has emerged as a safe, accurate, and time-saving electrode insertion technique due to its unparalleled potential for orthogonal and oblique insertion trajectories, guided by rigorous computer-assisted planning. SEEG exploration of the insular cortex remains difficult due to its anatomical location, hidden by the temporal and frontoparietal opercula. Furthermore, the close vicinity of Sylvian vessels makes surgical electrode insertion challenging. Some epilepsy surgery teams remain cautious about insular exploration due to the potential of neurovascular injury. However, several authors have published encouraging results regarding the technique's accuracy and safety in both children and adults. We will review the indications, techniques, and outcomes of insular SEEG exploration with emphasis on robot-assisted implantation.

Reversible Focal Dystonia Secondary to Giant Perivascular Spaces.

Giant perivascular spaces (PVS) are rare, CSF-filled, dilated cavities lined by the pia mater that are most often asymptomatic radiological findings but can sometimes cause neurological symptoms. We present two exceptional cases of secondary focal dystonia induced by the mass effect on the basal ganglia caused by giant diencephalic PVSs. In both cases, we chose a surgical stereotactic drainage approach as a treatment strategy that allowed controlling the movement disorders. The beneficial therapeutic effect was sustained at long-term follow-up. We believe that similar cases could be addressed successfully with this method.

Foot Drop After Iliocaval Vein Stenting: Radicular Syndrome from Stent Misplacement in Spinal Canal.

BACKGROUND: Endovascular procedures have become more and more prevalent in both general vascular and neurosurgical practices. Because these procedures rely on real-time bidimensional control through fluoroscopic guidance, they can be prone to spatial misplacement in the third dimension when not controlled in 2 different radiologic planes. CASE DESCRIPTION: We report a unique complication of an iliocaval vessel stenting procedure with misplacement of a venous stent in the spinal canal. This case illustrates the close vascular relationship between the large venous vessels of the abdomen and pelvis and epidural plexus of the spinal canal. CONCLUSIONS: The complex venous anatomy of the lumbar region and lumbar epidural space is illustrated in this unique case. We believe this may serve both vascular surgeons and neurosurgeons in their daily practice.

Frameless ROSA® Robot-Assisted Lead Implantation for Deep Brain Stimulation: Technique and Accuracy.

BACKGROUND: Frameless robotic-assisted surgery is an innovative technique for deep brain stimulation (DBS) that has not been assessed in a large cohort of patients. OBJECTIVE: To evaluate accuracy of DBS lead placement using the ROSA® robot (Zimmer Biomet) and a frameless registration. METHODS: All patients undergoing DBS surgery in our institution between 2012 and 2016 were prospectively included in an open label single-center study. Accuracy was evaluated by measuring the radial error (RE) of the first stylet implanted on each side and the RE of the final lead position at the target level. RE was measured on intraoperative telemetric X-rays (group 1), on intraoperative O-Arm® (Medtronic) computed tomography (CT) scans (group 2), and on postoperative CT scans or magnetic resonance imaging (MRI) in both groups. RESULTS: Of 144 consecutive patients, 119 were eligible for final analysis (123 DBS; 186 stylets; 192 leads). In group 1 (76 patients), the mean RE of the stylet was 0.57 ± 0.02 mm, 0.72 ± 0.03 mm for DBS lead measured intraoperatively, and 0.88 ± 0.04 mm for DBS lead measured postoperatively on CT scans. In group 2 (43 patients), the mean RE of the stylet was 0.68 ± 0.05 mm, 0.75 ± 0.04 mm for DBS lead measured intraoperatively; 0.86 ± 0.05 mm and 1.10 ± 0.08 mm for lead measured postoperatively on CT scans and on MRI, respectively No statistical difference regarding the RE of the final lead position was found between the different intraoperative imaging modalities and postoperative CT scans in both groups. CONCLUSION: Frameless ROSA® robot-assisted technique for DBS reached submillimeter accuracy. Intraoperative CT scans appeared to be reliable and sufficient to evaluate the final lead position.

Pulse generator battery life in deep brain stimulation: out with the old in with the less durable?

BACKGROUND: Battery life of the most commonly used implantable pulse generators in deep brain stimulation is limited. Device replacement is costly and may expose patients to additional risks. Driven by the observation that in our experience newer generation devices seemed to need earlier replacement than the older generation, we aimed to retrospectively analyze the battery life of two generations of non-rechargeable devices, manufactured by a single company (Medtronic, USA). METHODS: Battery life of 281 devices in 165 patients was taken into account for data analysis. This represented 243 older generation devices (Kinetra and Soletra) and 38 newer generation devices (Activa). RESULTS: The battery life of older generation stimulators was 2-fold longer than the newer generation. CONCLUSIONS: Newer devices are more versatile than the older generation. Their battery life is however significantly shorter. Development of next-generation devices needs to address this issue in order to limit health risks and reduce financial costs.

Anatomical predictors of cognitive decline after subthalamic stimulation in Parkinson's disease.

We investigated whether pre-operative MRI measures of focal brain atrophy could predict cognitive decline occurring after deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with Parkinson's disease (PD). For that purpose, we prospectively collected data of 42 consecutive patients with PD who underwent bilateral STN-DBS. Normalized brain structure volumes and cortical thicknesses were measured on pre-operative T1-weighted MRI. Patients were tested for their cognitive performances before surgery and 1 year after. After controlling for age, gender, pre-operative disease severity, change in dopaminomimetic dose after surgery and contact location, we found correlations: (1) between the variation of the total Mattis dementia rating scale (MDRS) score and left lateral ventricle volume (p = 0.032), (2) between the variation of the initiation/perseveration subscore of the MDRS and the left nucleus accumbens volume (p = 0.042) and the left lateral ventricle volume (p = 0.017) and (3) between the variation of the backward digit-span task and the right and left superior frontal gyrus thickness (p = 0.004 and p = 0.007, respectively). Left nucleus accumbens atrophy was associated with decline in the initiation/perseveration subscore with the largest effect size (d = - 1.64). Pre-operative left nucleus accumbens volume strongly predicted postoperative decline in the initiation/attention subscore (AUC = 0.92, p < 0.001, 96.3% sensitivity, 80.0% specificity, 92.9% PPV and 92.9% NPV). We conclude that the morphometric measures of brain atrophy usually associated with cognitive impairment in PD can also explain or predict a part of cognitive decline after bilateral STN-DBS. In particular, the left accumbens nucleus volume could be considered as a promising marker for guiding surgical decisions.