Patients awaiting surgery for neurosurgical diseases during the first wave of the COVID-19 pandemic in Spain: a multicentre cohort study.

OBJECTIVES: The large number of infected patients requiring mechanical ventilation has led to the postponement of scheduled neurosurgical procedures during the first wave of the COVID-19 pandemic. The aims of this study were to investigate the factors that influence the decision to postpone scheduled neurosurgical procedures and to evaluate the effect of the restriction in scheduled surgery adopted to deal with the first outbreak of the COVID-19 pandemic in Spain on the outcome of patients awaiting surgery. DESIGN: This was an observational retrospective study. SETTINGS: A tertiary-level multicentre study of neurosurgery activity between 1 March and 30 June 2020. PARTICIPANTS: A total of 680 patients awaiting any scheduled neurosurgical procedure were enrolled. 470 patients (69.1%) were awaiting surgery because of spine degenerative disease, 86 patients (12.6%) due to functional disorders, 58 patients (8.5%) due to brain or spine tumours, 25 patients (3.7%) due to cerebrospinal fluid (CSF) disorders and 17 patients (2.5%) due to cerebrovascular disease. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was mortality due to any reason and any deterioration of the specific neurosurgical condition. Second, we analysed the rate of confirmed SARS-CoV-2 infection. RESULTS: More than one-quarter of patients experienced clinical or radiological deterioration. The rate of worsening was higher among patients with functional (39.5%) or CSF disorders (40%). Two patients died (0.4%) during the waiting period, both because of a concurrent disease. We performed a multivariate logistic regression analysis to determine independent covariates associated with maintaining the surgical indication. We found that community SARS-CoV-2 incidence (OR=1.011, p<0.001), degenerative spine (OR=0.296, p=0.027) and expedited indications (OR=6.095, p<0.001) were independent factors for being operated on during the pandemic. CONCLUSIONS: Patients awaiting neurosurgery experienced significant collateral damage even when they were considered for scheduled procedures.

Primary central nervous system angiosarcoma with recurrent acute subdural hematoma.

Angiosarcoma is an infrequent tumor among sarcomas, especially presenting as a primary tumor within the central nervous system, which can lead to a rapid neurological deterioration and death in few months. We present a 41-year old man with a right frontal enhancing hemorrhagic lesion. Surgery was performed with histopathological findings suggesting a primary central nervous system angiosarcoma. He was discharged uneventfully and received adjuvant chemotherapy and radiotherapy. At 5 months, the follow-up MRI showed two lesions with an acute subdural hematoma, suggesting a relapse. Surgery was again conducted finding tumoral membranes attached to the internal layer of the duramater around the right hemisphere. The patient died a few days later due to the recurrence of the subdural hematoma. This case report illustrates a rare and lethal complication of an unusual tumor. The literature reviewed shows that gross-total resection with adjuvant radiotherapy seems to be the best treatment of choice.

Impact of the first wave of the SARS-CoV-2 pandemic on the outcome of neurosurgical patients: a nationwide study in Spain.

OBJECTIVE: To assess the effect of the first wave of the SARS-CoV-2 pandemic on the outcome of neurosurgical patients in Spain. SETTINGS: The initial flood of COVID-19 patients overwhelmed an unprepared healthcare system. Different measures were taken to deal with this overburden. The effect of these measures on neurosurgical patients, as well as the effect of COVID-19 itself, has not been thoroughly studied. PARTICIPANTS: This was a multicentre, nationwide, observational retrospective study of patients who underwent any neurosurgical operation from March to July 2020. INTERVENTIONS: An exploratory factorial analysis was performed to select the most relevant variables of the sample. PRIMARY AND SECONDARY OUTCOME MEASURES: Univariate and multivariate analyses were performed to identify independent predictors of mortality and postoperative SARS-CoV-2 infection. RESULTS: Sixteen hospitals registered 1677 operated patients. The overall mortality was 6.4%, and 2.9% (44 patients) suffered a perioperative SARS-CoV-2 infection. Of those infections, 24 were diagnosed postoperatively. Age (OR 1.05), perioperative SARS-CoV-2 infection (OR 4.7), community COVID-19 incidence (cases/105 people/week) (OR 1.006), postoperative neurological worsening (OR 5.9), postoperative need for airway support (OR 5.38), ASA grade ≥3 (OR 2.5) and preoperative GCS 3-8 (OR 2.82) were independently associated with mortality. For SARS-CoV-2 postoperative infection, screening swab test <72 hours preoperatively (OR 0.76), community COVID-19 incidence (cases/105 people/week) (OR 1.011), preoperative cognitive impairment (OR 2.784), postoperative sepsis (OR 3.807) and an absence of postoperative complications (OR 0.188) were independently associated. CONCLUSIONS: Perioperative SARS-CoV-2 infection in neurosurgical patients was associated with an increase in mortality by almost fivefold. Community COVID-19 incidence (cases/105 people/week) was a statistically independent predictor of mortality. TRIAL REGISTRATION NUMBER: CEIM 20/217.

Primary central nervous system angiosarcoma with recurrent acute subdural hematoma.

Angiosarcoma is an infrequent tumor among sarcomas, especially presenting as a primary tumor within the central nervous system, which can lead to a rapid neurological deterioration and death in few months. We present a 41-year old man with a right frontal enhancing hemorrhagic lesion. Surgery was performed with histopathological findings suggesting a primary central nervous system angiosarcoma. He was discharged uneventfully and received adjuvant chemotherapy and radiotherapy. At 5 months, the follow-up MRI showed two lesions with an acute subdural hematoma, suggesting a relapse. Surgery was again conducted finding tumoral membranes attached to the internal layer of the duramater around the right hemisphere. The patient died a few days later due to the recurrence of the subdural hematoma. This case report illustrates a rare and lethal complication of an unusual tumor. The literature reviewed shows that gross-total resection with adjuvant radiotherapy seems to be the best treatment of choice.

Drezotomía en el tratamiento del dolor por desaferentización: revisión de resultados y análisis de factores predictores de éxito / DREZotomy in the treatment of deafferentation pain: review of results and analysis of predictive factors for success

Antecedentes y objetivos El tratamiento del dolor por desaferentización mediante drezotomía espinal es una opción terapéutica contrastada en la literatura. En los últimos años, la drezotomía ha visto relegado su empleo a un segundo plano debido a la eclosión de las terapias neuromoduladoras. Los objetivos de este estudio son demostrar que la drezotomía continúa siendo un tratamiento efectivo y seguro, y analizar aquellos factores predictores de éxito. Pacientes y métodos Se realizó un estudio retrospectivo de todos los pacientes tratados en nuestro servicio mediante drezotomía espinal desde 1998 hasta 2018. Se excluyeron los casos de drezotomía bulbar. Se emplearon la escala visual analógica (EVA) y la reducción de la medicación habitual como variables resultado, y se analizaron variables demográficas, clínicas y quirúrgicas como factores predictores de éxito. Resultados Un total de 27 pacientes (51,9% mujeres) de 53,7 años de edad media fueron tratados mediante drezotomía. La etiología principal del dolor fue por avulsión de plexo braquial (55,6%) seguida de causa tumoral (18,5%). El tiempo medio de evolución del dolor fue de 8,4 años con una intensidad media de 8,7 según la EVA, pese a que el 63% de los pacientes habían recibido tratamiento neuroestimulador previo. Durante el postoperatorio inmediato un 77,8% de los pacientes presentaron una reducción del 50% o más en la EVA. Tras un seguimiento medio de 22 meses posdrezotomía, permaneció una reducción de al menos el 50% en la EVA en el 59,3% de los pacientes (reducción media de 4,9 puntos) permitiendo una reducción del tratamiento analgésico habitual en el 70,4% de ellos. La drezotomía en la avulsión de plexo braquial presentó una tasa de éxito (93%) superior al resto de patologías (41,7%) de manera significativa (p = 0,001) (AU)

Background and objectives The treatment of deafferentation pain by spinal DREZotomy is a proven therapeutic option in the literature. In recent years, use of DREZotomy has been relegated to second place due to the emergence of neuromodulation therapies. The objectives of this study are to demonstrate that DREZotomy continues to be an effective and safe treatment and to analyse predictive factors for success. Patients and methods A retrospective study was conducted of all patients treated in our department with spinal DREZotomy from 1998 to 2018. Bulbar DREZotomy procedures were excluded. A visual analogue scale (VAS) and the reduction of routine medication were used as outcome variables. Demographic, clinical and operative variables were analysed as predictive factors for success. Results A total of 27 patients (51.9% female) with a mean age of 53.7 years underwent DREZotomy. The main cause of pain was brachial plexus injury (BPI) (55.6%) followed by neoplasms (18.5%). The mean time of pain evolution was 8.4 years with a mean intensity of 8.7 according to the VAS, even though 63% of the patients had previously received neurostimulation therapy. Favourable outcome (≥ 50% pain reduction in the VAS) was observed in 77.8% of patients during the postoperative period and remained in 59.3% of patients after 22 months average follow-up (mean reduction of 4.9 points). This allowed for a reduction in routine analgesic treatment in 70.4% of them. DREZotomy in BPI-related pain presented a significantly higher success rate (93%) than the other pathologies (41.7%) (p = .001). No association was observed between outcome and age, gender, DREZ technique, duration of pain or previous neurostimulation therapies. There were six neurological complications, four post-operative transient neurological deficits and two permanent deficits (AU)

DREZotomy in the treatment of deafferentation pain: review of results and analysis of predictive factors for success. / Drezotomía en el tratamiento del dolor por desaferentización: revisión de resultados y análisis de factores predictores de éxito.

BACKGROUND AND OBJECTIVES: The treatment of deafferentation pain by spinal DREZotomy is a proven therapeutic option in the literature. In recent years, use of DREZotomy has been relegated to second place due to the emergence of neuromodulation therapies. The objectives of this study are to demonstrate that DREZotomy continues to be an effective and safe treatment and to analyse predictive factors for success. PATIENTS AND METHODS: A retrospective study was conducted of all patients treated in our department with spinal DREZotomy from 1998 to 2018. Bulbar DREZotomy procedures were excluded. A visual analogue scale (VAS) and the reduction of routine medication were used as outcome variables. Demographic, clinical and operative variables were analysed as predictive factors for success. RESULTS: A total of 27 patients (51.9% female) with a mean age of 53.7 years underwent DREZotomy. The main cause of pain was brachial plexus injury (BPI) (55.6%) followed by neoplasms (18.5%). The mean time of pain evolution was 8.4 years with a mean intensity of 8.7 according to the VAS, even though 63% of the patients had previously received neurostimulation therapy. Favourable outcome (≥50% pain reduction in the VAS) was observed in 77.8% of patients during the postoperative period and remained in 59.3% of patients after 22 months average follow-up (mean reduction of 4.9 points). This allowed for a reduction in routine analgesic treatment in 70.4% of them. DREZotomy in BPI-related pain presented a significantly higher success rate (93%) than the other pathologies (41.7%) (p=.001). No association was observed between outcome and age, gender, DREZ technique, duration of pain or previous neurostimulation therapies. There were six neurological complications, four post-operative transient neurological deficits and two permanent deficits. CONCLUSION: Dorsal root entry zone surgery is effective and safe for treating patients with deafferentation pain, especially after brachial plexus injury. It can be considered an alternative treatment after failed neurostimulation techniques for pain control. However, its indication should be considered as the first therapeutic option after medical therapy failure due to its good long-term results.

Reanimación cardiopulmonar en prono a propósito de un caso / Case report cardiopulmonary resuscitation in prone position

Prone position is necessary for some neurosurgical and othopedic procedures. Cardiopulmonary resuscitation (CPR) in prone position was first described by McNeil in 1989, since then several successful cases have been published. We report the case of a 72-year-old patient with history of stage IV breast cancer who presented acute spinal cord compression due to a vertebral fracture at T10 level. Surgical spinal cord decompression and posterior arthrodesis was performed. After three hours of surgery, cardiorespiratory arrest occur while patient was in prone position. Unestable spine and fixed head made turning the patient into supine position very difficult, consequently prone CPR manoeuvres were started with recovery of spontaneous circulation. In case of cardiorespiratory arrest in prone position, the intense fixation and the extent of the surgical incision make the change to supine a time-consuming and technically complex procedure. If cardiorespiratory arrest occurs in the prone position, CPR in the prone position might be reasonable.

La posición de decúbito prono es necesaria para la realización de algunos procedimientos neuroquirúrgicos y traumatológicos. La reanimación cardiopulmonar (RCP) en prono fue descrita por primera vez por McNeil en 1989, desde entonces se han publicado varios casos de RCP en prono con buen resultado. Presentamos el caso de una paciente de 72 años con antecedentes de carcinoma de mama estadio IV que presenta síndrome de compresión medular por fractura patológica a nivel de T10. Se decide realizar descompresión medular y artrodesis por vía posterior. A las 3 horas de la cirugía se produjo parada cardiorrespiratoria en prono. Dada la inestabilidad espinal y la fijación de la paciente, el cambio a supino era complejo por lo que se iniciaron maniobras de RCP en prono con posterior recuperación de circulación espontánea. En caso de parda cardiorrespiratoria en prono, la intensa fijación y la extensión de la incisión quirúrgica hace que el cambio a supino consuma tiempo y sea técnicamente complejo. Si la PCR ocurre en prono, está justificado iniciar las maniobras de RCP en esta posición.

Análisis del impacto clínico de la reclasificación diagnóstica de gliomas cerebrales según la clasificación de la Organización Mundial de la Salud (2016) / Analysis of the clinical impact of the diagnostic reclassification of brain gliomas according to the World Health Organization classification (2016)

Introducción: Desde la introducción de los criterios genéticos y moleculares en la clasificación de la Organización Mundial de la Salud (OMS) de tumores cerebrales de 2016, se ha producido una reclasificación diagnóstica entre determinados astrocitomas y oligodendrogliomas con discordancias histológicas y genéticas, cuyo pronóstico se desconoce. Objetivo: Analizar las implicaciones de la reclasificación diagnóstica de los gliomas cerebrales según los criterios de la OMS de 2016, especialmente según la mutación de la isocitrato deshidrogenasa (IDH) y la codeleción 1p19q. Pacientes y métodos. Estudio retrospectivo de los gliomas tratados desde el 1 de enero de 2012 hasta el 31 de diciembre de 2016, con análisis de los aspectos clinicorradiológicos y pronósticos, y con seguimiento disponible y completo hasta el 31 de marzo de 2019. Resultados: De 147 gliomas cerebrales, en 69 (astrocitomas u oligodendrogliomas de grados II-IV) se realizaron un diagnóstico molecular y una reevaluación diagnóstica. Se detectaron 24 gliomas reclasificados, habitualmente oligodendrogliomas que pasaron a astrocitomas, y que mostraron mayores supervivencias, derivadas de la no reclasificación en grado IV. Los gliomas reclasificados, todos de grados II/III, comenzaron mayoritariamente con crisis, sin focalidad, con lesiones únicas, <17 cm3 y con edema, aunque con similar supervivencia. Los factores pronósticos fueron: edad joven, focalidad, grado II y no captación de contraste o necrosis, o multiplicidad. No se detectaron variaciones según el patrón molecular con mutación en la IDH o codeleción. Conclusión: Los cambios diagnósticos tras la clasificación de la OMS de 2016 presentan características clinicorradiológicas específicas en esta serie, aunque no mayores supervivencias, si bien, por la supervivencia habitual en estos casos, precisarían un mayor tiempo de seguimiento

Introduction: Since the introduction of genetic and molecular criteria in the 2016 World Health Organization (WHO) classification of brain tumours, there has been a diagnostic reclassification between certain astrocytomas and oligodendrogliomas with histological and genetic discordances, the prognosis of which is unknown. Aim: To analyse the implications of the diagnostic reclassification of brain gliomas according to the 2016 WHO criteria, especially depending on isocitrate dehydrogenase (IDH) mutation and 1p19q codeletion. Patients and methods: We conducted a retrospective study of gliomas treated from 1 January 2012 to 31 December 2016, with analyses of clinicoradiological aspects and prognoses, and with available and complete follow-up until 31 March 2019. Results: From a total of 147 brain gliomas, a molecular diagnosis and a diagnostic re-evaluation were carried out in 69 cases (grade II-IV astrocytomas or oligodendrogliomas). Twenty-four reclassified gliomas were detected, usually oligodendrogliomas that became astrocytomas, and which showed greater survival, derived from their not being classified as grade IV. The reclassified gliomas, all grades II/III, mostly began with seizures, without focus, with single lesions, <17 cm3 and with oedema, although with similar survival rates. The prognostic factors were: young age, focus, grade II and no contrast enhancement or necrosis, or multiplicity. No variations were detected according to the molecular pattern with IDH mutation or codeletion. Conclusion: The changes in diagnosis after the WHO classification of 2016 present specific clinical-radiological characteristics in this series, but no greater survival, although, due to the habitual survival in these cases, they would require a longer follow-up time

Evaluación del impacto del cambio diagnóstico de los gliomas aplicando la nueva clasificación de la OMS de 2016 sobre una serie de casos / Assessment of the impact of glioma diagnostic reclassification following the new 2016 WHO classification on a series of cases

Antecedentes y objetivo: El objetivo de este trabajo es evaluar el cambio del diagnóstico molecular sobre el histológico de una serie de tumores gliales al revisar el diagnóstico con la clasificación de la OMS de 2016. Materiales y métodos: Se realiza un estudio retrospectivo de los tumores gliales (oligodendrogliomas y astrocitomas) tratados en nuestro centro entre enero de 2012 y junio de 2016, y una revisión diagnóstica según su estudio molecular. Se lleva a cabo el análisis estadístico de variables epidemiológicas, histológicas y de genética molecular (mutaciones en IDH y presencia de codeleción 1p19q), variación en el diagnóstico al introducir la nueva clasificación tumoral e impacto clínico de dicha reclasificación. Resultados: De los 147 casos de tumores gliales revisados, se obtuvo el diagnóstico molecular en 74 casos (50,3%). En 23 casos (31%) cambió el diagnóstico, predominando en 20 (87%) el diagnóstico previo de oligodendroglioma (69,6% grado II y 17,4% grado III). Solo 3 de los 23 casos cambiaron de diagnóstico inicial astrocitario al oligodendroglial. Respecto al patrón molecular en estos 23 casos, se detectó IDH mutado en 16 (69,6%) y codeleción 1p19q negativa en 20 (87%). Según la estirpe celular, de los 27 oligodendrogliomas de esta serie, 20 (74%) cambiaron de diagnóstico por tener la codeleción negativa, pasando a ser astrocitomas. Se observó una tendencia a un mayor cambio de diagnóstico en pacientes jóvenes (<40 años), p=0,065, mayoritariamente con diagnóstico previo de oligodendrogliomas, sin relación con el sexo. Además, se detectó una mayor frecuencia de cambio de diagnóstico entre los tumores con IDH mutado (69,6%), p=0,003. Respecto a la supervivencia o el patrón clínico, no se detectaron cambios significativos entre los tumores con o sin cambio diagnóstico, a pesar de no recibir tratamiento de elección, tras un seguimiento medio de 16 meses, en probable relación con el bajo grado lesional. Conclusiones: Dentro del espectro de tumores astrocitarios y oligodendrogliales en nuestro centro, la clasificación diagnóstica con genética molecular evidencia importantes cambios respecto al diagnóstico morfológico. Estos cambios afectan especialmente a los diagnósticos previos de oligodendrogliomas y a los pacientes jóvenes en los casos revisados, y con patrones moleculares de mutación en la IDH y de ausencia de codeleción 1p19q. Si bien se pueden plantear dudas respecto a la clínica, el pronóstico y el tratamiento realizado en estos casos, se requieren estudios específicos en estos aspectos para lograr unas conclusiones apropiadas

Background and objectives: The aim of this project is to assess diagnostic reclassification based on molecular data over morphology in a series of glial tumours since the introduction of the 2016 WHO classification of brain tumours. Materials and methods: Retrospective review of glial tumours (oligodendrogliomas and astrocytomas) treated in our centre between January 2012 and June 2016 in which a review of diagnosis was performed when molecular studies were added. Statistical analysis included evaluation of variables of epidemiology, morphology and molecular data (mainly IDH mutation and 1p19q codeletion), diagnostic changes after new classification was considered, and clinical impact in cases of diagnostic reclassification. Results: From a total of 147 glial tumours reviewed in our centre, molecular diagnosis was obtained in 74 cases (50.3%). Initial diagnosis changed in 23 cases (31%), and 20 (87%) of them had a prior histological diagnosis of oligodendroglioma (69.6% grade II - and 17.4% grade III). Only 3 of these 23 cases diagnosis changed from astrocytoma to oligodendroglioma. Among reclassified tumours, there was a common molecular pattern, as findings showed mutant IDH in 16 cases (69.6%) and no codeletion in 20 cases (87%). According to the cell of origin, of the whole group of 27 oligodendrogliomas in our series (reclassified and non-reclassifed), 20 cases (74%) became astrocytomas, despite typical oligodendroglial morphology, due to absence of 1p19q codeletion. There was a trend for diagnosis reclassification in younger patients (<40 years), P=.065, mainly in those with a prior diagnosis of oligodendroglioma, with no statistical differences based on gender or clinical data. Besides, reclassification was more common among tumours with mutant IDH (69.6%), P=.003, than those with wild type IDH. In terms of survival, despite receiving different treatments, no significant changes were detected between reclassified and non-reclassified tumours after a mean follow-up of 16 months, partly related to lower grade of these lesions. Conclusions: Within the spectrum of the glial tumours treated in our institution, this new classification including molecular genetics over morphological data has provided marked diagnostic changes. These changes appear mainly in tumours previously diagnosed as oligodendrogliomas and in younger patients, with molecular patterns of mutant IDH and 1p19q codeletion. Although diagnosis reclassification may affect clinic, prognosis or therapeutic management of these tumours, deeper and prospective studies on these specific aspects are needed

Assessment of the impact of glioma diagnostic reclassification following the new 2016 WHO classification on a series of cases. / Evaluación del impacto del cambio diagnóstico de los gliomas aplicando la nueva clasificación de la OMS de 2016 sobre una serie de casos.

BACKGROUND AND OBJECTIVES: The aim of this project is to assess diagnostic reclassification based on molecular data over morphology in a series of glial tumours since the introduction of the 2016 WHO classification of brain tumours. MATERIALS AND METHODS: Retrospective review of glial tumours (oligodendrogliomas and astrocytomas) treated in our centre between January 2012 and June 2016 in which a review of diagnosis was performed when molecular studies were added. Statistical analysis included evaluation of variables of epidemiology, morphology and molecular data (mainly IDH mutation and 1p19q codeletion), diagnostic changes after new classification was considered, and clinical impact in cases of diagnostic reclassification. RESULTS: From a total of 147 glial tumours reviewed in our centre, molecular diagnosis was obtained in 74 cases (50.3%). Initial diagnosis changed in 23 cases (31%), and 20 (87%) of them had a prior histological diagnosis of oligodendroglioma (69.6% grade ii and 17.4% grade iii). Only 3 of these 23 cases diagnosis changed from astrocytoma to oligodendroglioma. Among reclassified tumours, there was a common molecular pattern, as findings showed mutant IDH in 16 cases (69.6%) and no codeletion in 20 cases (87%). According to the cell of origin, of the whole group of 27 oligodendrogliomas in our series (reclassified and non-reclassifed), 20 cases (74%) became astrocytomas, despite typical oligodendroglial morphology, due to absence of 1p19q codeletion. There was a trend for diagnosis reclassification in younger patients (<40 years), P=.065, mainly in those with a prior diagnosis of oligodendroglioma, with no statistical differences based on gender or clinical data. Besides, reclassification was more common among tumours with mutant IDH (69.6%), P=.003, than those with wild type IDH. In terms of survival, despite receiving different treatments, no significant changes were detected between reclassified and non-reclassified tumours after a mean follow-up of 16 months, partly related to lower grade of these lesions. CONCLUSIONS: Within the spectrum of the glial tumours treated in our institution, this new classification including molecular genetics over morphological data has provided marked diagnostic changes. These changes appear mainly in tumours previously diagnosed as oligodendrogliomas and in younger patients, with molecular patterns of mutant IDH and 1p19q codeletion. Although diagnosis reclassification may affect clinic, prognosis or therapeutic management of these tumours, deeper and prospective studies on these specific aspects are needed.

A Novel and Freely Available Interactive 3d Model of the Internal Carotid Artery.

We describe a new and freely available 3D interactive model of the intracranial internal carotid artery (ICA) and the skull base that also allows to display and compare its main segment classifications. High-resolution 3D human angiography (isometric voxel's size 0.36 mm) and Computed Tomography angiography images were exported to Virtual Reality Modeling Language (VRML) format for processing in a 3D software platform and embedding in a 3D Portable Document Format (PDF) document that can be freely downloaded at http://diposit.ub.edu/dspace/handle/2445/112442 and runs under Acrobat Reader on Mac and Windows computers and Windows 10 tablets. The 3D-PDF allows for visualisation and interaction through JavaScript-based functions (including zoom, rotation, selective visualization and transparentation of structures or a predefined sequence view of the main segment classifications if desired). The ICA and its main branches and loops, the Gasserian ganglion, the petrolingual ligament and the proximal and distal dural rings within the skull base environment (anterior and posterior clinoid processes, silla turcica, ethmoid and sphenoid bones, orbital fossae) may be visualized from different perspectives. This interactive 3D-PDF provides virtual views of the ICA and becomes an innovative tool to improve the understanding of the neuroanatomy of the ICA and surrounding structures.