Neurosurgical Approach Research Articles

Acetazolamide modulates intracranial pressure directly by its action on the cerebrospinal fluid secretion apparatus

BackgroundElevated intracranial pressure (ICP) is observed in many neurological pathologies, e.g. hydrocephalus and stroke. This condition is routinely relieved with neurosurgical approaches, since effective and targeted pharmacological tools are still lacking. The carbonic anhydrase inhibitor, acetazolamide (AZE), may be employed to treat elevated ICP. However, its effectiveness is questioned, its location of action unresolved, and its tolerability low. Here, we determined the efficacy and mode of action of AZE in the rat .MethodsWe employed in vivo approaches including ICP and cerebrospinal fluid secretion measurements in anaesthetized rats and telemetric monitoring of ICP and blood pressure in awake rats in combination with ex vivo choroidal radioisotope flux assays and transcriptomic analysis.ResultsAZE effectively reduced the ICP, irrespective of the mode of drug administration and level of anaesthesia. The effect appeared to occur via a direct action on the choroid plexus and an associated decrease in cerebrospinal fluid secretion, and not indirectly via the systemic action of AZE on renal and vascular processes. Upon a single administration, the reduced ICP endured for approximately 10 h post-AZE delivery with no long-term changes of brain water content or choroidal transporter expression. However, a persistent reduction of ICP was secured with repeated AZE administrations throughout the day.ConclusionsAZE lowers ICP directly via its ability to reduce the choroid plexus CSF secretion, irrespective of mode of drug administration.

Specialised Surgical Instruments for Endoscopic and Endoscope-Assisted Neurosurgery: A Systematic Review of Safety, Efficacy and Usability.

Simple SummaryThe greatest technical barrier in endoscopic and endoscope-assisted neurosurgery is the instruments employed for these approaches. This systematic review aimed to identify specialised instruments for this type of surgery and evaluate their safety, efficacy and usability. We identified 50 instruments over 60 studies that were broadly safe and effective and generally considered to be ergonomic, though the learning curve was often noted as a disadvantage. Only eight studies compared the new instrument to standard instruments and comparisons were generally favourable to the new instrument. The development of novel and specialised instruments for endoscopic and endoscope-assisted neurosurgery is an area of interest for the field, but these instruments do not meet the need for improved articulation and future development should be based on established guidelines for neurosurgical innovation.While there have been great strides in endoscopic and endoscope-assisted neurosurgical approaches, particularly in the treatment of deep-sited brain and skull base tumours, the greatest technical barrier to their adoption has been the availability of suitable surgical instruments. This systematic review seeks to identify specialised instruments for these approaches and evaluate their safety, efficacy and usability. Conducted in accordance with the PRISMA guidelines, Medline, Embase, CENTRAL, SCOPUS and Web of Science were searched. Original research studies that reported the use of specialised mechanical instruments that manipulate tissue in human patients, cadavers or surgical models were included. The results identified 50 specialised instruments over 62 studies. Objective measures of safety were reported in 32 out of 62 studies, and 20 reported objective measures of efficacy. Instruments were broadly safe and effective with one instrument malfunction noted. Measures of usability were reported in 15 studies, with seven reporting on ergonomics and eight on the instruments learning curve. Instruments with reports on usability were generally considered to be ergonomic, though learning curve was often considered a disadvantage. Comparisons to standard instruments were made in eight studies and were generally favourable. While there are many specialised instruments for endoscopic and endoscope-assisted neurosurgery available, the evidence for their safety, efficacy and usability is limited with non-standardised reporting and few comparative studies to standard instruments. Future innovation should be tailored to unmet clinical needs, and evaluation guided by structured development processes.

Neurosurgery Practice During the COVID-19 Pandemic

Background and Aim: The viral agent in severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) is the cause of the novel coronavirus disease 2019 (COVID-19). It was first identified in December 2019 in the city of Wuhan, Hubei, China, and the World Health Organization declared it as an outbreak and a Public Health Emergency of International Concern on 30 January 2020, and a pandemic on 11 March 2020. Neurosurgeons are not prime in COVID-19 management but they continue for caring, visiting, and operating neurosurgical patients. In neurosurgical cases that need non-urgent operation, systematic SARS-CoV-2 testing of low-risk patients should be considered. In cases with positive SRAS-COV-2 testing, the procedures should be delayed until they are cured. The high-risk settings in the neurosurgical operation room are endotracheal intubation and extubation, operations in the vicinity of sinuses and/or mastoids, operations with accidental injury to respiratory or digestive tracts, and usage of aerosol-generating instruments on virioncontaminated tissues. The risk of SARS-COV-2 infection is decreased by delaying all nonemergent cases, replacing general anesthesia with other anesthesia methods, replacing neurosurgical approaches with alternative approaches that bypass the respiratory tract, and decreasing the usage of aerosol-generating instruments. Methods and Materials/Patients: This is a narrative study about COVID-19 infection in neurosurgery. Using the keywords SARS-COV2, neurosurgery, and COVID-19, all the relevant articles (about 52) were retrieved from Google Scholar, Medline, and PubMed and reviewed and critically analyzed. Results: Neurosurgeons can change neurosurgical routines in COVID-19 patients such as delaying all nonemergent cases, replacing general anesthesia with other anesthesia methods, replacing neurosurgical approaches with alternative approaches that bypass the respiratory tract, decreasing the usage of aerosol-generating instruments, and doing preoperative SRAS-COV-2 testing. Conclusion: For decreasing the risk of COVID-19 transmission in neurosurgery, we can change routine neurosurgical protocols. Without the prevention of COVID-19 transmission, all neurosurgeons, personnel, and patients will contract COVID-19.

LGG-11. Analysis of neurosurgical complications in pediatric supratentorial midline low-grade glioma – results from the German LGG studies

OBJECTIVE: Around 80% of all pediatric low-grade glioma (LGG) patients undergo at least one tumor surgery. Interventions in the supratentorial midline (SML) are particularly challenging due to the proximity of eloquent areas, yet associated complications are scarcely reported. We investigated the frequency of neurosurgical complications and related impairments and aimed at identifying risk factors for their appearance related to patient characteristics or the procedure. PATIENTS AND METHOD: Records were retrospectively analyzed from 321 patients with SML-LGG from the successive multicenter German LGG studies, who underwent neurosurgery at 63 hospitals between May 12th,1998 and June 27th, 2020. RESULTS: 543 operations (235 resections, 168 biopsies, 140 non-tumor interventions) were performed on 321 patients (54% male, median age 9 years, 11% NF1 positive, 43% visual pathway glioma). Surgical mortality rate was 0,93% (n=3). Applying the Drake classification postoperative surgical morbidity was observed in 259 cases (47,7%), medical morbidity in 103 cases (19%). 30-day persistence rate of newly developed neurological deficits was 44,8% (65/165 cases); neuroendocrine impairment affected 57 patients (17,8%), visual deterioration 34 (10,6%). Complications/impairments following resections were associated with patient age below 3 years at operation, tumor volume above 80 cm3, presence of hydrocephalus prior to surgery, complete resection, intervention in centers with fewer reported resections and surgery performed between 1998-2006 by univariate analysis. In contrast, the neurosurgical approach, tumor location, NF1 status as well as previous antineoplastic treatment were not associated with the frequency of complications. Regarding biopsies, open biopsies showed significantly more surgery-associated complications/impairments compared with stereotactic procedures. CONCLUSIONS: Neurosurgery-associated complications and impairments were frequent in pediatric patients with supratentorial midline LGG undergoing open surgery in the German LGG-studies. We identified six patient- and institution-associated factors that may increase the risk for surgical complications. Skills at the treating center and extent of resection should be considered appropriately prior to intervention.

SURG-07. The impact of early targeted therapy on the neurosurgical approach to pediatric low-grade glioma

We report two cases of pediatric low-grade glioma (pLGG) treated with vemurafenib, an oral BRAF-inhibitor: a 12-year-old girl with involvement of basal ganglia, hypothalamus, and diencephalic junction; a 3-year-old boy, with an optic pathway/hypothalamic glioma extending along the left optic tract and basal ganglia. Both received a biopsy and molecular analysis was performed in the girl’s tumor, showing BRAF V600E mutation. Therefore, instead of surgical removal planned by neurosurgeons, first-line treatment with vemurafenib was started: after one month 45% reduction of the mass according to RANO criteria was found, as well as better balance control and strong reduction of the right arm paresis; five months later, a 70% shrinkage was detected, stabilized to 76% after a year. The young boy first started chemotherapy with vincristine and carboplatin, but at the end of the induction phase the tumor had increased and ascites, hydrocephalus, and visual impairment occurred. Molecular testing showing BRAF V600E mutation on the initial tumor biopsy was obtained; therefore, the surgical option was postponed and therapy with vemurafenib started. After only three days, visual acuity and muscle tone improved; brain MRI showed a 34% reduction of the mass after one week, increased up to 65% after six months. Therefore, no ulterior surgery was necessary. In pLGG, the neurosurgical biopsy is essential to let an early and rapid molecular diagnosis of BRAF mutations and guide subsequent targeted therapies. Our cases demonstrate how a prompt radiological response to vemurafenib and the related clinical improvement can influence both therapeutic and surgical decisions, hopefully reducing the occurrence of second neurosurgery with associated risks of neurological sequelae. To our knowledge, this is the first report assessing such a quick shrinkage in pLGG treated with vemurafenib, highlighting the importance of an early investigation of BRAF status in all cases of LGG in children.

Virtual-Augmented Reality and Life-Like Neurosurgical Simulator for Training: First Evaluation of a Hands-On Experience for Residents.

BackgroundIn the recent years, growing interest in simulation-based surgical education has led to various practical alternatives for medical training. More recently, courses based on virtual reality (VR) and three-dimensional (3D)-printed models are available. In this paper, a hybrid (virtual and physical) neurosurgical simulator has been validated, equipped with augmented reality (AR) capabilities that can be used repeatedly to increase familiarity and improve the technical skills in human brain anatomy and neurosurgical approaches.MethodsThe neurosurgical simulator used in this study (UpSurgeOn Box, UpSurgeOn Srl, Assago, Milan) combines a virtual component and a physical component with an intermediate step to provide a hybrid solution. A first reported and evaluated practical experience on the anatomical 3D-printed model has been conducted with a total of 30 residents in neurosurgery. The residents had the possibility to choose a specific approach, focus on the correct patient positioning, and go over the chosen approach step-by-step, interacting with the model through AR application. Next, each practical surgical step on the 3D model was timed and qualitatively evaluated by 3 senior neurosurgeons. Quality and usability-grade surveys were filled out by participants.ResultsMore than 89% of the residents assessed that the application and the AR simulator were very helpful in improving the orientation skills during neurosurgical approaches. Indeed, 89.3% of participants found brain and skull anatomy highly realistic during their tasks. Moreover, workshop exercises were considered useful in increasing the competency and technical skills required in the operating room by 85.8 and 84.7% of residents, respectively. Data collected confirmed that the anatomical model and its application were intuitive, well-integrated, and easy to use.ConclusionThe hybrid AR and 3D-printed neurosurgical simulator could be a valid tool for neurosurgical training, capable of enhancing personal technical skills and competence. In addition, it could be easy to imagine how patient safety would increase and healthcare costs would be reduced, even if more studies are needed to investigate these aspects. The integration of simulators for training in neurosurgery as preparatory steps for the operating room should be recommended and further investigated given their huge potential.

Importance of neurosurgical expertise and multidisciplinary approach in pituitary patients

Importance of neurosurgical expertise and multidisciplinary approach in pituitary patients

Referred Trigeminal Pain from Greater Occipital Nerve Entrapment: Importance of Accurate Greater Occipital Nerve Decompression

Trigeminocervical complex (TCC) sensitization by chronic entrapment of the greater occipital nerve (GON) often causes difficult-to-understand referred trigeminal facial pain along with occipital neuralgia. This report emphasizes the importance of accurate diagnosis and GON decompression by describing a case of a 51-year-old female patient with referred trigeminal pain from occipital neuralgia misdiagnosed as chronic migraine. The patient underwent incomplete decompression surgery. She presented with a relentless stinging and stabbing pain in her left hemiface and temporo-occipital area for 8 years. The pain occurred suddenly without improvement after long-term medical and injection treatment. She was diagnosed with chronic migraine and underwent so-called “migraine surgery” three years ago, but to no avail. Incomplete decompression of the bilateral GONs within the trapezial tunnel was confirmed under a microscopic oblique-paramedian approach. After accurate decompression, the chronic stabbing pain in the left facial and temporo-occipital region disappeared. Only intermittent numbness was felt. It is important to recognize occipital neuralgia caused by chronic GON entrapment and referred facial pain caused by TCC sensitization. Referred pain still often seems to be misunderstood as various other diseases. Direct decompression of the trapezial tunnel using a neurosurgical microscopic approach based on an accurate assessment of anatomical considerations may be important for GON decompression.

Morphometric and Morphological Variants of Pterion with its Clinical Importance in South Indian Population

Background: Pterion is a critical neuroanatomical landmark in various neurosurgical approaches, including for the placement of burr holes. In addition, it also holds significance from radiological, anthropological, and forensic point of view. Thus, we undertook the current study to investigate the prevalence of different morphological types of pterion along with their morphometric parameters from adjacent bony landmarks in the south Indian population. Methodology: A total of 64 adult dry human skulls of unknown gender and age were included for the study. All skulls were grossly normal. The types of pterions were classified on both sides based on Murphy's classification. The vertical linear distance from the center of the pterion to the zygomatic arch (PZ) and to the anterior border of the frontozygomatic suture (PF) was measured with a digital vernier caliper. Data were statistically analyzed. Results: All four varieties of pterion were noticed. The sphenoparietal variety was found as most predominant bilaterally (81%), followed by epipteric (12.5%) stellate (3.9%) and frontotemporal (2.39%). One of the epipteric varieties consists of an unusually large ossicle. Pterion was typically located 3.59 ± 0.43cm behind the fronto zygomatic suture and 3.71 ± 0.34 cm above the zygomatic arch. Conclusion: The sphenoparietal variant of pterion was predominant on both sides, followed by epipteric variety.

Plastic closure of bone defects of anterior cranial fossa floor in surgery of benign and malignant craniofacial tumors

Objective: to analyze the results of using various methods of plastic closure of bone defects of the anterior cranial fossa (ACF) floor when removing craniofacial tumors of the ACF floor depending on the size of the defect. Materials and methods. A retrospective analysis of treatment outcomes of 122 patients with craniofacial tumors of the ACF floor was carried out. According to the nature of the lesions malignant craniofacial tumors were detected in 98 (80.3%) patients, and benign ones in 24 (19.7%) patients. The following neurosurgical approaches to craniofacial tumors of the ACF floor were used: bifrontal - in 58 (47.5%) patients, subcranial - in 49 (40.2%), transbasal Derome - in 8 (6.5%), frontotemporal - in 4 (3.25%), expanded endoscopic - in 3 (2.45%). In 52 (42.6%) cases, endoscopic endonasal assistance was used, most often in the case of plasty of large ACF floor defects to revise the surgical defect, assess the sufficiency of plasty and tamponade of the nasal cavity with balloon catheters. Results. Patients were divided into groups depending on the bone defect of the ACF floor: median - in 27 (22.1%), middle-expanded - in 71 (58.2%), middle-lateral - in 24 (19.7%). The following types of plasty of the bone defect of the ACF floor were used: pedicle flap - 83 (68.0%) cases, free flap - 22 (18.1%), pedicled periosteal flap with reinforcement - 17 (13.9%). Postoperative complications occurred in 17 (13.9%) patients: nasal liquorrhea in 10 (8.2%) patients (of which 6 underwent reoperation to eliminate it), in 7 patients it was complicated by meningoencephalitis, in other 7 (5.7 %) - meningoencephalitis without signs of nasal cerebrospinal fluid. Postoperative mortality was 0.71% (1 patient). The frequency of nasal cerebrospinal fluid in the group of plasty using a free flap was 13.6% (3 cases), meningoencephalitis - 4.5% (1 observation), in the group of plasty using pedicle flap - 4.8% (4 cases) and 6.0% (5 observations), in the group of plasty using a pedicle flap with reinforcement - 17.6% (3 cases) and 11.7% (2 observations). In 33 (27.1%) cases the use of the author's method of bone defect plasty of the ACF floor with duplication of complications were not registered. Conclusions. Significant size and spread of bone defects of the ACF floor increase the risk of postoperative complications. The use of free flaps for plasty of the bone defect of the ACF floor is ineffective and is associated with a high risk of complications. The proposed method of plasty of the posterior parts of the ACF floor by duplication of the periosteal flap promotes the sealing of the posterior parts, where suturing causes certain difficulties. Reinforcement of plasty from the side of the nasal cavity due to endoscopic technique using tamponade or balloon catheters reduces the incidence of postoperative complications.

137 A Review of Current Criteria for Risk of Aneurysmal Subarachnoid Haemorrhage

Abstract Introduction There is a need to evaluate the existing guidelines regarding the size criteria for the risk of rupture of intracranial aneurysms. The current understanding is that small intracranial aneurysms (less than 7 mm) are not at significant risk for rupture according to the ISUIA 1 & 2 trials. However, there have been several published series of rupture and subarachnoid haemorrhage from aneurysms less than 5 mm in both, anterior and posterior cerebral circulation. Methods We conducted a systematic review of aneurysmal subarachnoid haemorrhage, specifically to identify their size and the anatomical location at the time of rupture, using the healthcare databases advanced search. Results Our search yielded 1438 results matching our inclusion criteria. Our results demonstrated that 50.4 – 76.8% of aneurysms were under 7 mm in diameter at the time of rupture. Subarachnoid haemorrhage from smaller aneurysms (<5 mm) was also shown to present with poor prognoses (Hunt and Hess grades 4–5). There were no significant differences observed between the anterior and posterior circulation. Conclusions The existing criterion to determine the risk of rupture of intracranial aneurysms need to be updated, accounting for multiple clinical factors including, but not limited to, the size. With advances in endovascular treatments in recent years, the associated intra-procedural risks are greatly reduced compared to traditional neurosurgical approaches, making the argument for intervention at earlier presentations.

Prognosis in Traumatic Brain Injury

Abstract Objective To characterize the profile of TBI victims who required neurosurgical approach in two reference hospitals in the metropolitan area of Florianópolis, state of Santa Catarina, Brazil, and to identify the prognostic increase in the Pupil Reactivity Score when subtracted from the Glasgow Coma Score, found in the Glasgow-P. Additionally, to present demographic, etiological, clinical, and tomographic data, and associate them with the outcome of death. Methods Medical record data and computed tomography (CT) scans of patients with TBI undergoing neurosurgical procedures from January 2014 to April 2019, at 2 reference hospitals in the metropolitan area of Florianópolis, state of Santa Catarina, Brazil – Hospital Regional de São José Dr. Homero de Miranda Gomes (HRSJ-HMG, in the Portuguese acronym) and Hospital Governador Celso Ramos (HGCR, in the Portuguese acronym). Results The results of the 318 cases studied indicated that the male gender predominated (87.7%). The most affected age group was between 35 and 65 years old (47.5%). The main cause was motorcycle accidents (26.1%), followed by a fall from a height (16.4%). Most patients required admission to the intensive care unit (ICU) (85.8%), with an average duration of 13 days. The average total hospital stay was 28 days. Most cases needed external ventricular drain (EVD) (64.8%). The predominant tomographic classification was Marshall II (43.4%), followed by Marshall IV (26.1%). Most patients presented with extra-axial hematoma (64.2%), with subdural hematoma (SDH) being the most frequent (45%). Most patients presented with sequelae at hospital discharge (43.4%). Conclusion There was no clinically relevant increase between the Glasgow and Glasgow-P scores for the tested outcomes (need for decompressive craniectomy, midline shift, presence of basal cisterns obliteration, need for ICU admission, and death).

Novel approaches for quantifying beta synchrony in Parkinson's disease.

Despite the clinical and financial burden of Parkinson's disease (PD), there is no standardized, reliable biomarker to diagnose and track PD progression. Instead, PD is primarily assessed using subjective clinical rating scales and patient self-report. Such approaches can be imprecise, hindering diagnosis and disease monitoring. An objective biomarker would be beneficial for clinical care, refining diagnosis, and treatment. Due to widespread electrophysiological abnormalities both within and between brain structures in PD, development of electrophysiologic biomarkers may be feasible. Basal ganglia recordings acquired with neurosurgical approaches have revealed elevated power in the beta frequency range (13-30Hz) in PD, suggesting that beta power could be a putative PD biomarker. However, there are limitations to the use of beta power as a biomarker. Recent advances in analytic approaches have led to novel methods to quantify oscillatory synchrony in the beta frequency range. Here we describe some of these novel approaches in the context of PD and explore how they may serve as electrophysiological biomarkers. These novel signatures include (1) interactions between beta phase and broadband (> 50Hz, "gamma") amplitude (i.e., phase amplitude coupling, PAC), (2) asymmetries in waveform shape, (3) beta coherence, and (4) beta "bursts." Development of a robust, reliable, and readily accessible electrophysiologic biomarker would represent a major step towards more precise and personalized care in PD.

A distal anterior cerebral artery tripod branching to a bihemispheric pericallosal artery.

The anterior cerebral artery (ACA) branching pattern may be particularly complex and variant including bifurcations, trifurcations or quadrifurcations, thus leading to typical or atypical vessels. The bihemispheric ACA (BhACA) variant crosses the midline to supply the contralateral hemisphere. The current case highlights a left-sided ACA trifurcation into a bihemispheric pericallosal artery, and two ipsilateral atypical arteries: a callosomarginal artery of short course and a left-sided pericallosal artery of an aberrant course into the cingulate sulcus. The depicted trifurcation was characterized as a distal ACA tripod. The bihemispheric branch supplied the contralateral pericallosal area and coursed into the cingulate sulcus. Deviations from the typical ACA pattern, especially when they coexist are quite rare and may complicate neurosurgical approaches or raise diagnostic difficulties. The BhACA may be implicated in aneurysm formation and bilateral ischemia after its occlusion. Knowledge of such variants, as well as awareness of the complications they may be related to, is of great significance.

Special Report: Ethical Decision-Making in Contemporary Psychiatric Practice—An Evolving Challenge

Special Report: Ethical Decision-Making in Contemporary Psychiatric Practice—An Evolving Challenge

Central Nervous System Tumors in Children.

Central Nervous System Tumors in Children.

Chordoma as a neurosurgical pathology

Assess the significance of chordoma as a neurosurgical pathology, taking into account the latest edition of the WHO classification of soft tissues and bone tumors (2020). An analysis of 28 chordomas was carried out. All chordomas were histologically verified, including using immunohistochemical markers of notochordal differentiation (S100, EMA, keratin, brachiuria protein). Patients with chordomas accounted for 0.25% of the total number of neurosurgical patients. The vast majority (27) of chordomas had a cranio-vertebral localization. Sacral localization (S3-S5) of the tumor was detected in 1 patient. In 4 (15%) cases, operations were performed for the recurrence of chordoma. The tumors tended to grow into the structures of the skull, overgrown the vessels and nerves, and compress the adjacent brain structures. This was manifested by pain syndrome, neurological symptoms, impaired liquorodynamics. According to histopathological criteria, 27 (96%) cases of tumors were classified as conventional (usual) chordoma type, among them 7 corresponded to the chondroid subtype of the chordoma. In 1 case (4%), a dedifferentiated chordoma was detected. Chordoma, due to its axial localization, naturally involves adjacent structures of the nervous system, has clinically significant neuropathological manifestations, and often provides direct indications for a special neurosurgical approach. This requires its consideration not only as a bone, but also as a neurosurgical oncological pathology, along with other non-meningothelial (mesenchymal) tumors of the CNS.

Postoperative complications in endoscopic frontal transcortical surgery of lateral and third ventricle tumours

Neurosurgical approaches to lesions of the lateral and the third ventricles are divided into two fundamentally different groups: transcortical neurosurgical approaches, including - endoscopic and interhemispheric transcallosal micro-neurosurgical approaches. Complications in surgery of lateral and third ventricle tumours are often associated with the specific approach technique and could be transient. We analyzed postoperative neurological complications and the approach criteria on MRI or CT scans in the postoperative period such as localization of corticotomy, distance from corticotomy to the coronal suture, “angle of attack” after the frontal transcortical approach to the lateral and third ventricle based on 54 cases and presume transient nature of specific to approach complications and approaches’ factors that have a role in postoperative mutism.

Postoperative complications in endoscopic frontal transcortical surgery of lateral and third ventricle tumours

Neurosurgical approaches to lesions of the lateral and the third ventricles are divided into two fundamentally different groups: transcortical neurosurgical approaches, including - endoscopic and interhemispheric transcallosal microneurosurgical approaches. Complications in surgery of lateral and third ventricle tumours are often associated with the specific approach technique and could be transient. We analyzed postoperative neurological complications and the approach criteria on MRI or CT scans in postoperative period such as localization of corticotomy, distance from corticotomy to coronal suture, “angle of attack” after the frontal transcortical approach to the lateral and third ventricle based on 54 cases and presume transient nature of specific to approach complications and approaches’ factors that have role in postoperative mutism.

Functional Topography of the Human Subthalamic Nucleus: Relevance for Subthalamotomy in Parkinson's Disease.

The subthalamic nucleus (STN) is considered a key structure in motor, behavioral, and emotional control. Although identification of the functional topography of the STN has therapeutic implications in the treatment of the motor features of Parkinson's disease (PD), the details of its functional and somatotopic organization in humans are not well understood. The aim of this study was to characterize the functional organization of the STN and its correlation with the motor outcomes induced by subthalamotomy. We used diffusion-weighted imaging to assess STN connectivity patterns in 23 healthy control subjects and 86 patients with PD, of whom 39 received unilateral subthalamotomy. Analytical tractography was used to reconstruct structural cortico-subthalamic connectivity. A diffusion-weighted imaging/functional magnetic resonance imaging-driven somatotopic parcellation of the STN was defined to delineate the representation of the upper and lower limb in the STN. We confirmed a connectional gradient to sensorimotor, supplementary-motor, associative, and limbic cortical regions, spanning from posterior-dorsal-lateral to anterior-ventral-medial portions of the STN, with intermediate overlapping zones. Functional magnetic resonance imaging-driven parcellation demonstrated dual segregation of motor cortico-subthalamic projections in humans. Moreover, the relationship between lesion topography and functional anatomy of the STN explains specific improvement in bradykinesia, rigidity, and tremor induced by subthalamotomy. Our results support an interplay between segregation and integration of cortico-subthalamic projections, suggesting the coexistence of parallel and convergent information processing. Identifying the functional topography of the STN will facilitate better definition of the optimal location for functional neurosurgical approaches, that is, electrode placement and lesion location, and improve specific cardinal features in PD. © 2021 International Parkinson and Movement Disorder Society.