Morphometric Analysis of Stylomastoid Foramen and its Clinical Significance / Análisis Morfométrico del Foramen Estilomastoideo y su Importancia Clínica

SUMMARY: The stylomastoid foramen is located on the inferior surface of the petrous part of the temporal bone between the base of the styloid process and mastoid processes. Through the stylomastoid foramen the facial nerve completes its intracranial part. The aim of this study was to analyze the morphometric parameters, shape and position of the stylomastoid foramen on the skulls in Serbian population, and to correlate it with gender and body side. The study included 44 dry adult skulls (88 stylomastoid foramen). After we determined the gender, the skulls were photographed, and then distances of the stylomastoid foramen from various important landmarks of the skull base were measured in programme ImageJ. The shape and position of the stylomastoid foramen were also noted. The statistical significance was found in male skulls between right and left side in relation to parameter (P2) the shortest distance from the upper end of the anterior margin of the mastoid process (MP) to the center of stylomastoid foramen (CSMF), and on the left side for parameter (P6) the shortest distance between CSMF and the line passing through the tip of the MP in relation to gender. The most common shape of the stylomastoid foramen was round in 46 (52.27 %) cases, and most common position was on the line passing through the upper end of the anterior margin of both MP in 36 (40.91 %) and medially to the line connecting the tips of the MP and styloid process in 88 (100 %) cases. The results of this study will be useful for neurosurgeons during surgeries on the facial nerve trunk or anesthetics to give facial nerve block near the foramen and prevent its complications.

El foramen estilomastoideo se encuentra en la superficie inferior de la parte petrosa del hueso temporal entre la base del proceso estiloides y el proceso mastoides. A través del foramen estilomastoideo el nervio facial completa su parte intracraneal. El objetivo de este estudio fue analizar los parámetros morfométricos, la forma y la posición del foramen estilomastoideo en cráneos de población serbia y correlacionarlos con el sexo y el lado del cuerpo. El estudio incluyó 44 cráneos adultos secos (88 forámenes estilomastoideos). Después de determinar el sexo, se fotografiaron los cráneos y luego se midieron en el programa ImageJ las distancias del foramen estilomastoideo desde varios puntos importantes de la base del cráneo. También se observó la forma y posición del foramen estilomastoideo. La significación estadística se encontró en cráneos de hombres entre el lado derecho e izquierdo en relación al parámetro (P2) la distancia más corta desde el extremo superior del margen anterior del proceso mastoides (PM) hasta el centro del foramen estilomastoideo (CFM), y en el lado izquierdo para el parámetro (P6) la distancia más corta entre CFM y la línea que pasa por la punta del PM en relación al sexo. La forma más común del foramen estilomastoideo era redonda en 46 (52,27 %) casos, y la posición más común estaba en la línea que pasa por el extremo superior del margen anterior de ambos PM en 36 (40,91 %) y medialmente a la línea que conecta las puntas del PM y el proceso estiloides en 88 (100 %) casos. Los resultados de este estudio serán útiles para los neurocirujanos durante las cirugías en el tronco del nervio facial o los anestésicos para bloquear el nervio facial cerca del foramen y prevenir sus complicaciones.

Barrera de reparación de la base craneal en los abordajes endonasales endoscópicos / Skull base reconstruction barrier in endoscopic endonasal approaches

Introducción: Los abordajes endonasales endoscópicos son los procedimientos de elección para tumores mediales en la base craneal por su seguridad y efectividad. La reparación de la base craneal constituye un elevado desafío. Objetivo: Evaluar la efectividad de la construcción de una barrera de reconstrucción de la base craneal en pacientes con tumores de la base craneal operados por procedimientos endonasales endoscópicos. Método: Se realizó un estudio descriptivo, que incluyó a 70 pacientes del Hospital Hermanos Ameijeiras operados de tumores de la base craneal por procedimientos endonasales endoscópicos. Se construyó una barrera de reparación de la base craneal para aislar el compartimiento nasosinusal del intracraneal. Se determinó la eficiencia de la barrera de reparación mediante aspectos clínicos y endoscópicos. Se definieron aspectos a evaluar en relación con la vitalidad de la barrera de reparación con el empleo de la fibrina rica en plaquetas y leucocitos. Resultados: Se evidenció una barrera de reparación eficiente en el 98,6 por ciento. En relación con estado de vitalidad de la barrera se apreció una adherencia, granulación en el 98,6 por ciento de pacientes, mientras una angiogénesis de 97,1 por ciento. La incidencia de fístula de líquido cefalorraquídeo posoperatoria fue de solo 1,4 por ciento. Conclusiones: El presente estudio evidencia el efecto positivo de la construcción de una barrera de reparación eficiente de la base craneal por vía endonasal endoscópica con disminución significativa de fístula de líquido cefalorraquídeo y sus complicaciones(AU)

Introduction: Endoscopic endonasal approaches are the procedures of choice for medial tumors in the cranial base given their safety and effectiveness. Repair of the cranial base constitutes a high challenge. Objective: To evaluate the effectiveness of constructing a cranial base reconstruction barrier in patients with cranial base tumors operated on by endoscopic endonasal approaches. Method: A descriptive study was carried out, which included 70 patients from the Hermanos Ameijeiras Hospital operated on for cranial base tumors using endoscopic endonasal approaches. A cranial base repair barrier was constructed to isolate the sinonasal and intracranial compartments. The efficiency of the repair barrier was determined through clinical and endoscopic aspects. Aspects were defined to be evaluated in relation to the vitality of the repair barrier with the use of fibrin rich in platelets and leukocytes. Results: An efficient repair barrier was evident in 98.6 percent. In relation to the state of vitality of the barrier, adhesion and granulation were observed in 98.6 percent of patients, while angiogenesis was observed in 97.1 percent. The incidence of postoperative cerebrospinal fluid leak was only 1.4 percent. Conclusions: The present study shows the positive effect of the construction of an efficient repair barrier of the cranial base in endoscopic endonasal approaches with a significant reduction in cerebrospinal fluid leak and its complications(AU)

Anatomía microquirúrgica del seno cavernoso: revisión anatómica y manejo multimodal / Microsurgical Anatomy of the Cavernous Sinus: Anatomical Review and Multimodal Management

Introducción: La cirugía del seno cavernoso se consideró durante mucho tiempo inviable (no accesible para el hombre) (5,31) debido al riesgo de sangrado o lesión de estructuras neurovasculares críticas, como la ACI, el nervio oculomotor, troclear y abducens (5.31). Desde entonces, numerosos estudios han contribuido a comprender la anatomía microquirúrgica del seno cavernoso. En 1965, Parkinson (25) realizó el primer abordaje del seno cavernoso para el tratamiento de la fístula carótida-cavernosa. Fue el comienzo de la era moderna en la cirugía del seno cavernoso y abrió la puerta a muchas publicaciones que detallan los abordajes quirúrgicos de diversas lesiones dentro y alrededor del seno cavernoso. Junto al desarrollo y la mejora de la neuroimagen y la anatomía microquirúrgica, permitieron acceder con éxito al seno cavernoso. Nuestro objetivo es presentar una revisión narrativa de vanguardia de la anatomía microquirúrgica del seno cavernoso y el manejo interdisciplinario. Para lograr este propósito, se realizó la disección cadavérica de 2 cabezas (cuatro senos cavernosos) reflejada en 2 casos quirúrgicos, además de una revisión bibliográfica exhaustiva que orienta el manejo multimodal de los tumores que se encuentran dentro o alrededor del seno cavernoso. Objetivo: Describir la anatomía quirúrgica del seno cavernoso a través de disecciones cadavéricas y su aplicación microquirúrgica. Materiales y métodos: Se estudiaron 4 senos cavernosos cadavéricos humanos fijados en formol. Las arterias y venas fueron inyectadas con silicona coloreada, las imágenes fueron tomadas con una cámara DSLR Nikon 3400 profesional de 24,2 megapíxeles. Resultados: El seno cavernoso es un compartimento dural que contiene estructuras neurovasculares críticas, cuya disección debe ser realizada de forma cuidadosa y prolija por el inminente riesgo de lesión de las mismas. Es así que lesiones confinadas por ejemplo a la pared lateral (caso clínico 2) tienen mayor probabilidad de remoción total, por lo tanto mejor pronóstico, no así las lesiones que invaden el seno cavernoso (caso clínico 1) donde la probabilidad de remoción total disminuye y el riesgo de lesión neurovascular aumenta. Conclusiones: El conocimiento preciso de la anatomía microquirúrgica del seno cavernoso y el manejo multimodal son cruciales en el manejo y pronóstico del paciente(AU)

Background: Cavernous sinus surgery was long considered unfeasible (not accessible to humans) (5.31) due to the risk of bleeding or injury to critical neurovascular structures, such as the ICA, oculomotor, trochlear and abducens nerves (5.31). Since then, numerous studies have contributed to understanding the microsurgical anatomy of the cavernous sinus. In 1965, Parkinson (25) performed the first approach to the cavernous sinus for the treatment of carotid-cavernous fistula. This was the beginning of the modern era in cavernous sinus surgery and opens the door to many publications detailing surgical approaches to various injuries in and around the cavernous sinus. Together with the development and improvement of neuroimaging and microsurgical anatomy, they allowed successful access to the cavernous sinus. Our goal is to present a state-of-the-art narrative review of cavernous sinus microsurgical anatomy and interdisciplinary management. To achieve this purpose, cadaveric dissection of 2 heads (four cavernous sinuses) was performed, reflected in 2 surgical cases, in addition to an exhaustive literature review that guides the multimodal management of tumors found within or around the cavernous sinus. Objective: The aim of this study is to describe the surgical anatomy of the cavernous sinus through cadaveric dissections and its microsurgical application. Methods: 4 human cadaveric cavernous sinuses fixed in formalin were studied, the arteries and veins were injected with colored silicone, the images were taken with a 24.2-megapixel Nikon 3400 professional DSLR camera. Results: The cavernous sinus is a dural compartment that contains critical neurovascular structures, whose dissection must be performed carefully and neatly due to the imminent risk of injury to them, so lesions confined, for example, to the lateral wall (clinical case 2 ) have a higher probability of total removal and therefore a better prognosis, but not lesions that invade the cavernous sinus (clinical case 1) itself, where the probability of total removal decreases and the risk of neurovascular injury increases. Conclusions: Precise knowledge of the microsurgical anatomy of the cavernous sinus and multimodal management are crucial in the management and prognosis of the patient

Lipotransferencias en defectos estéticos post neuroquirúrgicos / Lipotransferences in post neurosurgical aesthetic defects

Introducción y objetivo: Existen numerosos procedimientos en los cuales más allá de la adecuada manipulación del músculo temporal y del cierre craneal, los pacientes pueden presentar defecto óseo, muscular por atrofia y asimetría facial consecuente, provocando un malestar psicológico y deterioro funcional. Nuestro equipo decidió aunar los conocimientos de cirugía plástica y aplicarlos a reconstrucciones craneales con lipotranferencias en pacientes post neuroquirúrgicos. El objetivo del siguiente trabajo consiste en presentar los resultados en una serie de pacientes donde se aplicó la mencionada técnica. Materiales y métodos: Durante 2022 se realizaron 45 procedimientos de lipotransferencias para corrección de defectos craneofaciales, de los cuales 29 fueron femeninos y 16 masculinos. Todos presentaban el antecedente quirúrgico de craneotomías pterionales y sus variantes, abordajes orbitocigomáticos y transcigomáticos, con el consiguiente déficit de volumen. Resultados: El procedimiento se realizó de manera ambulatoria, con anestesia local y en un tiempo promedio de 30 a 40 minutos. Se utilizó como zona donante la región hemiabdominal inferior; procesamiento de la grasa mediante técnica de decantación e inyección en la zona receptora a nivel craneo facial. Los pacientes toleraron el procedimiento adecuadamente sin complicaciones intraoperatoria ni eventos sobreagregados. Conclusión: La lipotransferencia constituye una técnica mínimamente invasiva, con baja morbilidad y altas tasas de efectividad en cuanto al resultado estético y a la satisfacción por parte del paciente. Es una herramienta que todo neurocirujano debería considerar ante un defecto secundario a un abordaje anterolateral a la base del cráneo(AU)

Background: There are numerous procedures in which, beyond adequate manipulation of the temporalis muscle and cranial closure, patients may present bone and muscle defects due to atrophy and consequent facial asymmetry, causing psychological discomfort and functional deterioration. Our team decided to combine the knowledge of plastic surgery and apply it to cranial reconstructions with fat transfers in post neurosurgical patients. The objective of the following work is to present the results in a series of patients where the aforementioned technique was applied. Methods: During the year 2022, 45 fat transfer procedures were performed for the correction of craniofacial defects, of which 29 were female and 16 male. All had a surgical history of pterional craniotomies and their variants, orbitozygomatic and transzygomatic approaches, with the consequent volume deficit. Results: The procedure was performed on an outpatient basis, with local anesthesia and in an average time of 30 to 40 minutes. The lower hemiabdominal region was used as the donor area, processing the fat using the decantation technique and injection into the receptor area at the craniofacial level. The patients tolerated the procedure adequately without intraoperative complications or superadded events. Conclusion: Fat transfer is a minimally invasive technique, with low morbidity and high rates of effectiveness in terms of aesthetic results and patient satisfaction. It is a tool that every neurosurgeon should consider when faced with a defect secondary to an anterolateral approach to the skull base(AU)

Fístula nasal de líquido cefalorraquídeo post-traumática. Resultados de la implementación de un protocolo de trabajo / Post-traumatic cerebrospinal fluid nasal leak. Results of the implementation of a work protocol

Introducción: Los pacientes con fracturas de base de cráneo anterior post traumatismo encéfalo-craneano tienen alto riesgo de fístula de líquido céfalo-raquídeo por las fosas nasales. Es importante el manejo oportuno y apropiado, evitando así complicaciones; razón por la cual se desarrolló el "protocolo HP" para su tratamiento quirúrgico. Objetivo: Comunicar la utilidad del "protocolo HP" en el manejo de la fístula de líquido céfalo-raquídeo de la base de cráneo anterior. Materiales y métodos: Estudio transversal retrospectivo con pacientes ≥ 15 años con diagnóstico de fístula de líquido céfalo-raquídeo nasal post traumatismo encéfalo-craneano, desde 1/1/2016 hasta 31/8/2021 que ingresaron al hospital y requirieron cirugía de reparación, con 28 pacientes incluidos, el valor p ˂0,05 (estadísticamente significativo). Resultados: 96,4% hombres, mayoría adultos jóvenes con traumatismo encéfalo-craneano leve; 82,1% presentó fístula de líquido céfalo-raquídeo temprana. Todos requirieron reparación transcraneal frontal, en 67,9% fue bilateral. La reparación antes de los 7 días fue en el 39,3%, 7-21 días en 46,4% y después de 21 días en 14,3% de los casos. Uso de drenaje lumbar continuo: preoperatorio 10,7%, intraoperatorio 60,7%, postoperatorio 46,4%. En el 89,3% la ubicación de la fístula de líquido céfalo-raquídeo intra-quirúrgica fue congruente con la tomografía. Desde el 2020 se sistematizó el manejo de las fístula de líquido céfalo-raquídeo. La recurrencia fue de 10,7% antes del 2020 (posteriormente fue de 0%), asociándose con Glasgow bajo e inicio de fístula de líquido céfalo-raquídeo 7 días post traumatismo encéfalo-craneano (p˂0,05). Complicaciones encontradas: meningitis 28,6%, convulsión 25%, anosmia 14,3%, neumoencéfalo a tensión 7,1% y absceso 3,6%. Mortalidad por fístula de líquido céfalo-raquídeo: 3,6%. Curación 96,4%. Conclusiones: La aplicación del "Protocolo HP" tuvo resultados satisfactorios. La tasa de recurrencia postoperatoria de fístula de líquido céfalo-raquídeo nasal post traumatismo encéfalo-craneano fue 0%(AU)

Background: Patients with anterior skull base fractures after traumatic brain injury have a high risk of cerebrospinal fluid leak through the nostrils. Timely and appropriate management is important, avoiding complications. The "HP protocol" for surgical treatment was developed. Objectives: To communicate the utility of the "HP protocol" in the management of the anterior skull base cerebrospinal fluid leak. Methods: Retrospective cross-sectional study; patients ≥ 15 years old with a diagnosis of nasal cerebrospinal fluid leak after traumatic brain injury, who were admitted at the hospital from 1/1/2016 to 8/31/2021 and required surgery. Included 28 patients, p value ˂0.05 (statistically significant). Results: 96.4% men, mostly young adults with mild traumatic brain injury; 82.1% presented early cerebrospinal fluid leak. All required frontal transcranial repair, in 67.9% it was bilateral. Repair before 7 days was in 39.3%, 7-21 days in 46.4%, and after 21 days in 14.3%. Use of continuous lumbar drainage: preoperative 10.7%, intraoperative 60.7%, postoperative 46.4%. In 89.3%, the location of the intraoperative cerebrospinal fluid leak was consistent with the CT scan. Since 2020, the management of the cerebrospinal fluid leak was systematized. The recurrence was 10.7% before 2020; after it was 0% and associated with low Glasgow and onset of cerebrospinal fluid leak 7 days after traumatic brain injury (p<0.05). Complications: meningitis 28.6%, seizure 25%, anosmia 14.3%, high tension pneumocephalus 7.1% and abscess 3.6%. Cerebrospinal fluid leak mortality: 3.6%. Cure 96.4%. Conclusions: The application of the "HP Protocol" had satisfactory results. The post traumatic brain injury nasal cerebrospinal fluid leak recurrence rate was 0%

Factores radiológicos predictores de grado de resección en pacientes con schwannomas vestibulares / Radiological factors that predict the degree of resection and functional preservation in patients with vestibular schwannomas

Introducción: Existen diversos factores predictores de grado de resección en la cirugía de los schwannomas vestibulares (SV). Nuestro equipo en Tucumán realizó un estudio sistemático perioperatorio con un protocolo específico de resonancia magnética (RM) en estos pacientes. El objetivo del presente estudio fue determinar la utilidad de la RM como predictor de grado de resección de los SV. Materiales y métodos: Se realizó un estudio de serie, de tipo correlacional, descriptivo y retrospectivo de pacientes operados de SV, por nuestro equipo en Tucumán, entre enero 2014 y diciembre 2020 (n:92). Se realizó correlación estadística, entre las características imagenológicas con el grado de resección. Resultados: Un tumor sólido aumenta 39,19 veces la probabilidad de tener una resección completa en comparación con un tumor quístico. Conclusión: La RM permite definir adecuadamente la consistencia tumoral; un tumor sólido se asocia a una mayor probabilidad de resección total(AU)

Background: There are various predictors of degree of resection surgery for vestibular schwannomas (SV). Our team in Tucumán carried out a systematic perioperative study with a specific magnetic resonance imaging (MRI) protocol in these patients. The objective of the present study was to determine the usefulness of MRI as a predictor of the degree of resection of VS. Methods: A serial, correlational, descriptive, and retrospective study of patients operated on for SV was carried out by our team in Tucumán, between January 2014 and December 2020 (n: 92). Statistical correlation was made between the imaging characteristics with the degree of resection. Results: A solid tumor increases 39.19 times the probability of having a complete resection compared to a cystic tumor. Conclusion: MRI allows to adequately define tumor consistency; a solid tumor is associated with a higher probability of total resection(AU)

Factores que influyen en el grado de resección y propuesta de escala preoperatoria para el manejo de meningiomas de base de cráneo / Predictive factors in the extent of resection and proposal of a preoperative scale for the management of skull base meningiomas

Objetivos: identificar factores que intervienen en el grado de resección de los meningiomas de base de cráneo y proponer una escala para calcular la probabilidad de resección total. Materiales y métodos: estudio unicéntrico, observacional, retrospectivo, de pacientes operados en el período 06/2018 ­ 06/2022. Se utilizaron como variables: edad, clínica, localización, tamaño, embolización previa, edema perilesional, calcio intratumoral, características en T2 y T1 e invasión ósea. El grado de resección se midió con la clasificación de Simpson tradicional y también se dividió en resección total (Simpson I, II y III) y subtotal (Simpson IV y V). Con los resultados se propuso una escala teniendo en cuenta las variables con significación estadística (p < 0.05). Se realizó una revisión bibliográfica del tema. Resultados: Se operaron un total de 23 pacientes. Fueron estadísticamente significativas asociadas con el grado de Simpson, la localización (p 0,002) y el tamaño (p 0,001). Asociada con resección total y subtotal, la invasión ósea (p 0,013). Para la escala utilizamos: localización (anterior 1 punto, posterior 2 puntos, medial 2 puntos y medial que involucra seno cavernoso 3 puntos), tamaño (<5 cm 1 punto, >5 cm 2 puntos) e invasión ósea (no 1 punto y si 2 puntos). Realizamos un análisis inferencial y se observó asociación entre la escala realizada y el grado de resección (p 0,005). Conclusión: En nuestro estudio se observó una asociación entre el tamaño, la localización y la invasión ósea con el grado de resección conseguido. Propusimos una escala para medir la probabilidad de resección total(AU)

Objectives: identify factors that intervene in the degree of resection of skull base meningiomas and propose a scale to calculate the probability of total resection. Materials and methods: single-center, observational, retrospective study of patients operated in the period 06/2018 - 06/2022. The following variables were used: age, symptoms, location, size, previous embolization, perilesional edema, intratumoral calcium, characteristics in T2 and T1 and bone invasion. The degree of resection was measured using the traditional Simpson scale and was also divided into total (Simpson I, II, and III) and subtotal (Simpson IV and V) resection. With the results, a scale was proposed taking into account the variables with statistical significance (p < 0.05). A bibliographic review of the subject was carried out. Results: A total of 23 patients were operated. They were statistically significant associated with Simpson's grade the location (p 0.002) and size (p 0.001). Associated with total and subtotal resection, the bone invasion (p 0.013). For the scale we use: location (anterior 1 point, posterior 2 points, medial 2 points and medial involving the cavernous sinus 3 points), size (<5 cm 1 point, >5 cm 2 points) and bone invasion (no 1 point and yes 2 points). We performed an inferential analysis and an association was observed between the scale used and the degree of resection (p 0.005). Conclusion: In our study, an association was observed between the size, location and bone invasion with the degree of resection achieved. We proposed a scale to measure the probability of total resection(AU)

Diagnosis and treatment of rare malignant temporal bone tumors / 临床耳鼻咽喉头颈外科杂志

Objective:To analyze the diagnosis, treatment and prognosis of patients with rare malignant tumors of the temporal bone. Methods:Four cases of rare temporal bone malignant tumors in our hospital between March 2014 and December 2020 were reviewed, including two cases of chondrosarcoma, one case of fibrosarcoma and one case of endolymphatic cystic papillary adenocarcinoma. There were three males and one female, ages between 28 and 56 years at the time of surgery. Common symptoms included hearing loss, facioplegia, tinnitus, and headache. All patients underwent imaging examinations to evaluate the extent of the lesions. Tumors were removed by subtotal temporal bone resection or infratemporal fossa approach, and postoperative adjuvant radiotherapy was applied if necessary. Results:One of the two chondrosarcoma patients was cured by complete resection of the tumor for 75 months, the other one recurred after the first excision of the tumor and underwent infratemporal fossa approach resection of skull base mass again with no recurrence found yet for 112 months. One patient with fibrosarcoma survived for 28 months after surgery with a positive margin and post-operative radiotherapy. One patient with endolymphatic cystic papillary adenocarcinoma recurred 12 months after subtotal lithotomy, and underwent subtotal temporal bone resection again, combined with radiotherapy. No recurrence was found for 63 months. Conclusion:The incidence of rare temporal bone malignant tumors is extremely low, the location is hidden, and the symptoms are atypical. Attention should be paid for early detection and early treatment. Surgical resection is the main treatment, and radiotherapy can be supplemented in the advanced stage or with a positive margin.

Current diagnosis and treatment of skull base osteomyelitis / 临床耳鼻咽喉头颈外科杂志

Skull base osteomyelitis is a rare, refractory, and potentially fatal disease primarily caused by otogenic and sino rhinogenic infections. At times, it can mimic neoplasia complicating the diagnosis. With the use of antibiotics, advancements in diagnostic methods, and skull base surgical techniques, the mortality rate has significantly improved. However, the successful diagnosis and treatment of the disease is still challenging due to delayed diagnosis, lengthy treatment course, a tendency for relapse and lack of guidelines. Therefore, this article aims to review the progress in the diagnosis and treatment of skull base osteomyelitis.

Impact of sinonasal anatomic changes after endoscopic anterior skull base surgery on nasal airflow and air conditioning: a computational fluid dynamics study / 中华耳鼻咽喉头颈外科杂志

Objective: To analyze the impact of the sinonasal anatomic changes after endonasal endoscopic anterior skull base surgery on the nasal airflow and heating and humidification by computational fluid dynamics (CFD), and to explore the correlation between the postoperative CFD parameters and the subjective symptoms of the patients. Methods: The clinical data in the Rhinology Department of the First Affiliated Hospital of Zhengzhou University from 2016 to 2021 were retrospectively analyzed. The patients received the endoscopic resection of the anterior skull base tumor were selected as the case group, and the adults whose CT scans had no sinonasal abnormalities were chosen as the control group. The CFD simulation was performed on the sinonasal models after reconstructed from the patients' sinus CT images during the post-surgical follow-up. All the patients were asked to complete the Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) to assess the subjective symptoms. The comparison between two independent groups and the correlation analysis were carried out by using the Mann-Whitney U test and the Spearman correlation test in the SPSS 26.0 software. Results: Nineteen patients (including 8 males and 11 females, from 22 to 67 years old) in the case group and 2 patients (a male of 38 years old and a female of 45 years old) in the control group were enrolled in this study. After the anterior skull base surgery, the high-speed airflow moved to the upper part of the nasal cavity, and the lowest temperature shifted upwards on the choana. Comparing with the control group, the ratio of nasal mucosal surface area to nasal ventilation volume in the case group decreased [0.41 (0.40, 0.41) mm-1 vs 0.32 (0.30, 0.38) mm-1; Z=-2.04, P=0.041], the air flow in the upper and middle part of the nasal cavity increased [61.14 (59.78, 62.51)% vs 78.07 (76.22, 94.43)%; Z=-2.28, P=0.023], the nasal resistance decreased [0.024 (0.022, 0.026) Pa·s/ml vs 0.016 (0.009, 0.018) Pa·s/ml; Z=-2.29, P=0.022], the lowest temperature in the middle of the nasal cavity decreased [28.29 (27.23, 29.35)℃ vs 25.06 (24.07, 25.50)℃; Z=-2.28, P=0.023], the nasal heating efficiency decreased [98.74 (97.95, 99.52)% vs 82.16 (80.24, 86.91)%; Z=-2.28, P=0.023], the lowest relative humidity decreased [(79.62 (76.55, 82.69)% vs 73.28 (71.27, 75.05)%; Z=-2.28, P=0.023], and the nasal humidification efficiency decreased [99.50 (97.69, 101.30)% vs 86.09 (79.33, 87.16)%; Z=-2.28, P=0.023]. The ENS6Q total scores of all patients in the case group were less than 11 points. There was a moderate negative correlation between the proportion of the inferior airflow in the post-surgical nasal cavity negatively and the ENS6Q total scores (rs=-0.50, P=0.029). Conclusions: The sinonasal anatomic changes after the endoscopic anterior skull base surgery alter the nasal airflow patterns, reducing the efficiency of nasal heating and humidification. However, the post-surgical occurrence tendency of the empty nose syndrome is weak.

Analysis of the efficacy of endoscopic transnasal surgery for sinonasal and skull base adenoid cystic carcinoma / 中华耳鼻咽喉头颈外科杂志

Objective: To evaluate the efficacy of endoscopic transnasal surgery for sinonasal and skull base adenoid cystic carcinoma (ACC), and to analyze the prognostic factors. Methods: Data of 82 patients (43 females and 39 males, at a median age of 49 years old) with sinonasal and skull base ACC who were admitted to XuanWu Hospital, Capital Medical University between June 2007 and June 2021 were analyzed retrospectively. The patients were staged according to American Joint Committee on Cancer (AJCC) 8th edition. The disease overall survival(OS) and disease-free survival(DFS) rates were calculated by Kaplan-Meier analysis. Cox regression model was used for multivariate prognostic analysis. Results: There were 4 patients with stage Ⅱ, 14 patients with stage Ⅲ, and 64 patients with stage Ⅳ. The treatment strategies included purely endoscopic surgery (n=42), endoscopic surgery plus radiotherapy (n=32) and endoscopic surgery plus radiochemotherapy (n=8). Followed up for 8 to 177 months, the 5-year OS and DFS rates was 63.0% and 51.6%, respectively. The 10-year OS and DFS rates was 51.2% and 31.8%, respectively. The multivariate Cox regression analysis showed that late T stage and internal carotid artery (ICA) involvement were the independent prognostic factors for survival in sinonasal and skull base ACC (all P<0.05). The OS of patients who received surgery or surgery plus radiotherapy was significantly higher than that of patients who received surgery plus radiochemotherapy (all P<0.05). Conclusions: Endoscopic transonasal surgery or combing with radiotherapy is an effective procedure for the treatment of sinonasal and skull base ACC. Late T stage and ICA involvement indicate poor prognosis.

Acupuncture of revised acupoint combination around the skull base for post-stroke mild cognitive impairment: a randomized controlled trial / 中国针灸

OBJECTIVE@#To observe the clinical efficacy of acupuncture of revised acupoint combination around the skull base in treating post-stroke mild cognitive impairment (PSMCI), and preliminary explore its action mechanism.@*METHODS@#A total of 76 PSMCI patients were randomly divided into an observation group (38 cases, 4 cases dropped off) and a control group (38 cases, 3 cases dropped off, 1 case was removed). In the observation group, acupuncture of revised acupoint combination around the skull base (bilateral Fengchi [GB 20], Wangu [GB 12], Tianzhu [BL 10] and Yamen [GV 15], Baihui [GV 20]) was used for treatment. In the control group, 8 non-meridian and non-acupoint points at the distal end were selected for shallow puncture treatment. Retaining the needles of 30 min, once every other day,3 times a week for 4 weeks in both groups. The scores of Montreal cognitive assessment (MoCA), mini-mental state examination (MMSE), Barthel index (BI) and serum levels of cystatin C (Cys-C) and homocysteine (Hcy) were compared in the two groups before and after treatment, and the clinical efficacy was evaluated.@*RESULTS@#After treatment, the scores of MoCA were increased compared with those before treatment in the two groups (P<0.05), and the score in the observation group was higher than that in the control group (P<0.05). The scores of MMSE and BI were increased compared with those before treatment in the observation group (P<0.05), and the score of MMSE in the observation group was higher than that in the control group (P<0.05). After treatment, the serum levels of Cys-C and Hcy were decreased compared with those before treatment in the observation group (P<0.05), and lower than those in the control group (P<0.05). After treatment, the serum level of Cys-C was increased compared with that before treatment in the control group (P<0.05). The total effective rate of the observation group was 88.2% (30/34), which was higher than 32.4% (11/34) of the control group (P<0.05).@*CONCLUSION@#Acupuncture of revised acupoint combination around the skull base can improve cognitive function and daily living ability of PSMCI patients, which may be related to the down regulation of serum levels of Cys-C and Hcy.

Clinical study of endoscopic surgery for recurrent nasopharyngeal carcinoma / 临床耳鼻咽喉头颈外科杂志

Objective:To compare the clinical effects and complications of surgery + chemotherapy and radiotherapy + chemotherapy in patients with nasopharyngeal carcinoma recurrence, so as to compare the safety and efficacy of two different therapeutic methods. Methods:A retrospective analysis was performed on 40 patients with recurrent nasopharyngeal carcinoma after radiotherapy and chemotherapy admitted to our hospital from January 2016 to June 2020. Among them, 26 patients were treated with surgery. The recurrent tumor was removed under nasal endoscope, and the frozen resection margin was negative during the operation. Chemotherapy was continued for stage Ⅲ and Ⅳ patients from 3 to 5 weeks after surgery. Fourteen patients received secondary radiotherapy and chemotherapy. Postoperative complications and survival rate were observed. Results:There were 14 patients in the secondary chemoradiotherapy group（control group） and 26 patients in the nasal endoscopic surgery group（observation group）. Among the 26 patients, 19 patients underwent nasal septal mucosal repair, 5 patients underwent temporal muscle flap repair, 2 patients underwent submental flap repair, 2 patients had nasal septal mucosal flap necrosis and cerebrospinal fluid leakage, and the temporal muscle flap was used for secondary repair in the second stage operation, and 8 patients needed cervical lymph node dissection. The patients recovered well after surgery, and the patients in stage Ⅲ and Ⅳ were treated with chemotherapy after 3 weeks to 5 weeks according to the patient's wound condition. There were significant differences in the incidence of complications and 1-, 2-, and 3-year survival rates between the two groups（P<0.05）. Conclusion:Patients with recurrent nasopharyngeal carcinoma can be treated by nasal endoscopic surgery to remove the tumor, and the use of pedicled nasal septal mucosal flap or temporal muscle flap for skull base reconstruction, The operation can effectively prevent major complications such as internal carotid artery rupture and hemorrhage, and improve the survival rate and quality of life of patients. It provides a safe and effective treatment for patients with recurrent nasopharyngeal carcinoma.

Research progress of necrotizing otitis externa / 临床耳鼻咽喉头颈外科杂志

Necrotizing otitis externa is a progressive infectious disease involving the external auditory canal and even the skull base, which can lead to serious complications and even death if not treated in time. In this paper, the latest advances in etiology, pathogenesis, clinical manifestations, diagnosis and treatment were reviewed based on previous literature, providing reference for clinical diagnosis, treatment and future research.

Radiologic evaluation of the anterior and posterior ethmoidal foramen and optic canal by paranasal sinus computed tomography scan among adult Filipinos

Objective@#To measure the average distances from anterior lacrimal crest (ALC) to anterior ethmoidal foramen (AEF), anterior ethmoidal foramen to posterior ethmoidal foramen (PEF) and posterior ethmoidal foramen to optic canal (OC) using plain paranasal sinus (PNS) computed tomography (CT) scans of adults in a tertiary private hospital in the Philippines. @*Methods@#Design: Retrospective review of plain PNS CT scans. Setting: Tertiary Private Teaching Hospital. Participants: One hundred four (104) plain PNS CT scans from January 2018 to December 2020 were considered for inclusion. @*Results@#Of the 104 PNS CT scans, 35 were excluded - seven for age less than eighteen, six for undistinguishable PEF and twenty-two for chronic rhinosinusitis. The remaining 69 PNS CT scans demonstrated identifiable structures, with overall average distances from ALC to AEF of 23.71 ± 2.43 mm, AEF to PEF of 10.87 ± 2.39 mm and PEF to OC of 7.39 ± 2.28 mm. @*Conclusion@#Our study suggests average distances for localization of vital structures such as the anterior ethmoidal artery, posterior ethmoidal artery and optic nerve among Filipinos. Because of considerable variation between and within sexes, individual measurements should still be obtained for each patient in performing endonasal, skull base and orbital surgery.

Pediatric SMARCB1/INI1-deficient poorly differentiated chordoma of the skull base: report of five cases and review of literature / 中华病理学杂志

Objective: To investigate the clinicopathological characteristics and differential diagnosis of pediatric SMARCB1/INI1-deficient poorly differentiated chordoma (PDC) of the skull base. Methods: Five cases of SMARCB1/INI1-deficient PDC were identified in 139 cases of chordoma diagnosed in Sanbo Brain Institute, Capital Medical University, Beijing, China from March 2017 to March 2021. The clinical and imaging data of the 5 PDCs were collected. H&E and immunohistochemical staining, and DNA methylation array were used, and the relevant literatures were reviewed. Results: All 5 PDCs were located at the clivus. The average age of the patients was 6.4 years, ranging from 3 to 16 years. Three patients were female and two were male. Morphologically, in contrast with classical chordomas, they presented as epithelioid or spindle tumor cells organized in sheets or nests, with necrosis, active mitoses, and infiltration into surrounding tissue. All cases showed positivity of CKpan, EMA, vimentin and brachyury (nuclear stain), and loss of nuclear SMARCB1/INI1 expression. S-100 protein expression was not frequent (2/5). Ki-67 proliferative index was high (20%-50%). All cases had over-expressed p53. It was necessary to differentiate SMARCB1/INI1-dificient PDC from SMARCB1/INI1-dificient tumors occurring at skull base of children or the tumors with epithelial and spindle cell morphological features. The 3 PDCs with DNA methylation testing showed the methylation profiles different from the pediatric atypical teratoid/rhabdoid tumors. They formed an independent methylation profile cluster. The clinical prognosis of the 5 patients was poor, and the overall survival time was 2-17 months. Conclusions: PDC is a special subtype of chordoma, which often affects children and occurs in the clivus. The PDC shares epithelioid or spindle cell morphologic features which are different from the classic chordoma. Besides the typical immunohistochemical profile of chordoma, PDC also has loss of nuclear SMARCB1/INI1 expression and distinct epigenetic characteristics.

Brainstem auditory evoked potential combined with high resolution cranial base CT can optimize the diagnosis of auditory nerve injury / 中华创伤杂志(英文版)

PURPOSE@#Auditory nerve injury is one of the most common nerve injury complications of skull base fractures. However, there is currently a lack of auxiliary examination methods for its direct diagnosis. The purpose of this study was to find a more efficient and accurate means of diagnosis for auditory nerve injury.@*METHODS@#Through retrospectively analyzing the results of brainstem auditory evoked potential (BAEP) and high-resolution CT (HRCT) in 37 patients with hearing impairment following trauma from January 1, 2018 to July 31, 2020, the role of the two inspection methods in the diagnosis of auditory nerve injury was studied. Inclusion criteria were patient had a clear history of trauma and unilateral hearing impairment after trauma; while exclusion criteria were: (1) severe patient with a Glasgow coma scale score ≤5 because these patients were classified as severe head injury and admitted to the intensive care unit, (2) patient in the subacute stage admitted 72 h after trauma, and (3) patient with prior hearing impairment before trauma. According to Goodman's classification of hearing impairment, the patients were divided into low/medium/severe injury groups. In addition, patients were divided into HRCT-positive and negative groups for further investigation with their BAEP results. The positive rates of BEAP for each group were observed, and the results were analyzed by Chi-square test (p < 0.05, regarded as statistical difference).@*RESULTS@#A total of 37 patients were included, including 21 males and 16 females. All of them were hospitalized patients with GCS score of 6-15 at the time of admission. The BAEP positive rate in the medium and severe injury group was 100%, which was significantly higher than that in the low injury group (27.27%) (p < 0.01). The rate of BEAP positivity was significantly higher in the HRCT-positive group (20/30, 66.7%) than in the HRCT-negative group (1/7, 14.3%) (p < 0.05). Twenty patients (54.05%) were both positive for BEAP and HRCT test, and considered to have auditory nerve damage. Six patients (16.22%) were both negative for BEAP and HRCT test, and 10 patients (27.03%) were BAEP-negative but HRCT-positive: all the 16 patients were considered as non-neurological injury. The rest 1 case (2.70%) was BAEP-positive but HRCT-negative, which we speculate may have auditory nerve concussion.@*CONCLUSION@#By way of BAEP combining with skull base HRCT, we may improve the accuracy of the diagnosis of auditory nerve injury. Such a diagnostic strategy may be beneficial to guiding treatment plans and evaluating prognosis.

Análise do retorno venoso intra e extracraniano em pacientes com craniossinostoses complexas e sindrômicas / Analysis of intra and extracranial venous return in patients with complex and syndromic craniosynostosis

Introdução. Retorno venoso extracraniano anormal é um importante fator relacionado às craniossinostoses complexas, sendo responsável por alta morbimortalidade. Associa-se a essa circulação, a estenose ou atresia do forame jugular, existindo dúvida na literatura se a presença de circulação colateral venosa é causa da estenose de forame, gerando hipertensão venosa; se o desenvolvimento da circulação venosa acontece como consequência da hipertensão intracraniana ou se existem componentes intrínsecos levando à formação de veias anômalas. Objetivo. Analisar o retorno venoso completo (intra e extracraniano) pré-operatório de pacientes com craniossinostoses complexas e sindrômicas e avaliar a sua relação com a: morfologia da base do crânio, funcionalidade dos forames e seios durais, hipertensão intracraniana e diagnostico sindrômico e molecular. Método. Estudo Retrospectivo e prospectivo de pacientes com craniossinostose complexa ou sindrômica submetidos à angiotomografia com fase venosa no Instituto Fernandes Figueira a partir de 2014. Para avaliação da gravidade do retorno venoso extracraniano foi elaborada uma classificação vascular, categorizando os pacientes em leves, moderados e graves. Essa classificação consistiu em uma pontuação em cada região de circulação colateral estudada, variando de 0 a 3. Desta forma, sendo 9 regiões de interesse (frontais, parietais, mastoides, condilares esquerda e direita e circulação transoccipital), a classificação variou entre 0 quando ausência completa de circulação colateral até 27, considerado a possibilidade mais grave apresentada. De acordo com o Cluster Hierárquico, os pacientes foram classificados em 3 categorias de circulação venosa extracraniana: Leve ­ pontuação vascular entre 0 e 9; Moderada ­ pontuação vascular entre 10 e 18; Grave ­ pontuação vascular entre 19 e 27. Os 3 grupos Moderada ­ pontuação vascular entre 10 e 18; Grave ­ pontuação vascular entre 19 e 27. Os 3 grupos foram comparados quanto à morfologia da base do crânio (áreas, medidas anteroposteriores e volumes do forame jugular, forame magno e fossa posterior), quanto ao retorno venoso intracraniano (seios venosos durais, funcionalidade do forame jugular), quanto à hipertensão intracraniana (número de suturas acometidas, presença de malformação de Chiari I, hidrocefalia, ventriculomegalia) e quanto às síndromes apresentadas (manifestações fenotípicas e estudo molecular). Resultados. Dentre o total de 45 pacientes, 44,4% (n= 20) pertenciam ao grupo leve, 37,8% (n= 17) ao grupo moderado e 17,8% (n= 8) ao grupo grave. A circulação venosa extracraniana não se correlacionou com as medidas anteroposteriores, transversas, de área e de volume dos forames jugulares, forame magno ou da fossa posterior, com o número de suturas acometidas, com a classificação dos seios venosos intracranianos e da fossa posterior, com a hidrocefalia ou ventriculomegalia. A malformação de Chiari I é mais frequente em pacientes mais graves (p valor <0,001). As mutações identificadas se correlacionaram com a gravidade da circulação venosa extracraniana (pvalor <0,001). Conclusões. A estratificação de pacientes em uma classificação vascular permite a avaliação mais adequada dos fatores que historicamente são relacionados à circulação venosa colateral em Craniossinostoses complexas e sindrômicas. As alterações venosas extracranianas não se correlacionaram diretamente com as alterações morfológicas da base do crânio, com a funcionalidade dos seios durais ou com sinais de hipertensão intracraniana. Essas alterações parecem ser resultado de manifestações intrínsecas relacionadas ao genótipo, sendo as mutações no gene FGFR2 mais gravemente relacionadas à circulação venosa extracraniana. Pacientes com síndrome de Pfeiffer apresentaram a classificação venosa extracraniana mais grave, seguido pelas síndromes de Crouzon, Apert, Jackson-Weiss, Saerthre-Chotzen e craniossinostoses complexas negativas. As veias emissárias mais frequentemente encontradas foram as condilares e mastóides, seguidas da circulação transóssea occipital. Atresia funcional do forame jugular se correlaciona com a gravidade da circulação venosa extracraniana e pode ser consequência da atividade molecular intrínseca no endotélio durante a formação do sistema venoso.

Introduction. Abnormal extracranial venous outflow is an important factor related to complex craniosynostosis, that can lead to high morbidity and mortality. It has been associated with stenosis or atresia of the jugular foramen. In fact, there is doubt in the literature if the collateral venous circulation is caused by Jugular foramen stenosis, generating venous hypertension or if the development of the venous circulation happens as a consequence of intracranial hypertension or whether if there are intrinsic components leading to the formation of anomalous veins. Objective. To analyze the preoperative complete venous outflow (intra and extracranial) of patients with complex and syndromic craniosynostosis and to evaluate its relationship with: morphology of the skull base, functionality of the jugular foramina and dural sinuses, intracranial hypertension and syndromic and molecular diagnosis. Method. A retrospective and prospective study of patients with complex or syndromic craniosynostosis on CT angiography with venous phase at Instituto Fernandes Figueira from 2014 to 2022. To assess the severity of extracranial venous drainage, a vascular classification was developed, categorizing patients into mild, moderate and severe. The classification consisted of a score in each region of collateral circulation studied, ranging from 0 to 3. Thus, with 9 regions of interest (frontal, parietal, mastoid, left and right condylar and transoccipital circulation), the classification ranged from 0 when absence collateral circulation up to 27, considered the most serious possibility presented. According to the Hierarchical Cluster, patients were in 3 extracranial circulation categories: Mild ­ vascular assessment between 0 and 9; Moderate ­ vascular assessment between 10 and 18; Severe ­ vascular assessment between 19 and 27. The 3 groups were compared regarding skull base morphology (areas, measurements of jugular foramen and foramen magnum, and posterior fossa volumes), intracranial venous outflow (dural venous sinuses, jugular foramen functionality), and intracranial hypertension (number of affected sutures, presence of Chiari I malformation, hydrocephalus, ventriculomegaly) and the syndromes presented (phenotypic manifestations and molecular study). Results. Among the 45 patients, 44.4% (n=20) belonged to the mild group, 37.8% (n=17) to the moderate group and 17.8% (n=8) to the severe group. The extracranial venous circulation does not correlate with the anteroposterior, transverse, area and volume measurements of the jugular foramen, foramen magnum or posterior fossa, with the number of affected sutures, with the intracranial venous sinuses and the posterior fossa, with the hydrocephalus or ventriculomegaly. Chiari I malformation correlates with the most severe patients (p value <0.001). The mutations identified correlate with the severity of the extracranial venous circulation (p-value <0.001). Conclusions. The stratification of patients in a vascular classification allows a more adequate evaluation of the factors that are historically related to the collateral venous circulation in complex and syndromic craniosynostosis. Extracranial venous changes did not directly correlate with morphological changes in the skull base, functionality of the dural sinuses, or with signs of intracranial hypertension. These alterations seem to be the result of intrinsic manifestations related to the genotype, with mutations in the FGFR2 gene most severely related to extracranial venous circulation. Patients with Pfeiffer syndrome had the most severe extracranial venous classification, followed by Crouzon, Apert, Jackson-Weiss, Saerthre-Chotzen and complex negative craniosynostosis. The emissary veins most frequently found were the condylar and mastoid veins, followed by the occipital transosseous circulation. Functional atresia of the jugular foramen correlates with the severity of extracranial venous circulation and may be a consequence of intrinsic molecular activity in the endothelium during formation of the venous system.

Rinosinusitis micótica alérgica con destrucción de base de cráneo / Allergic fungal rhinosinusitis with skull base destruction

La sinusitis micótica alérgica es una enfermedad inflamatoria de la mucosa rinosinusal producida por hongos que pueden aislarse de la cavidad de nasal de individuos sanos. Se produce indirectamente por los hongos que actúan como antígeno y desencadenan una reacción inmunológica mediada por IgE que origina pólipos y una secreción mucosa espesa con detritus e hifas denominada mucina. Su presentación clínica más frecuente es una sinusitis crónica unilateral o bilateral con pólipos. Con menos frecuencia, las sustancias originadas por la desgranulación de los eosinófilos producen remodelación o destrucción ósea y la sinusitis puede simular una neoplasia. Se describe el caso clínico de un paciente que padeció una sinusitis micótica alérgica con destrucción ósea masiva de la base del cráneo y que tuvo extensión intracraneal extradural e intraorbitaria de la enfermedad. Fue tratado con éxito mediante cirugía y corticoides. (AU)

Allergic fungal sinusitis is an inflammatory disease of the rhinosinusal mucosa caused by fungi that can be isolated from the nasal cavity of healthy individuals. The pathology is produced indirectly by the fungus that acts as an antigen and triggers an IgE-mediated allergic reaction that causes polyps and a thick mucous discharge with detritus and hyphae called mucin. Its most common clinical presentation is unilateral or bilateral chronic sinusitis with polyps. Less commonly, substances originated by the degranulation of eosinophils cause bone remodeling or destruction, and sinusitis can simulate a neoplasia. We describe the clinical case of a patient who suffered from allergic fungal sinusitis with massive bone destruction of the skull base and who had intracranial, extradural and intraorbital extension of the disease. He was successfully treated with surgery and corticosteroids.Key words: allergic fungal sinusitis, intracranial extension, endoscopic surgery, transorbital transpalpebral approach. (AU)

Extracranial landmarks for surgical skull base approaches / Puntos de referencia extracraneales para abordajes quirúrgicos de la base del cráneo

SUMMARY: Surgical operations regarding to skull base are challenging and reliable anatomical landmarks are required. There is a lack of knowledge on anatomical variations in this region. The aim of this study was to determine the safe extracranial landmarks for surgical approach to the skull base. In this study, 23 adult dry skulls were evaluated: the age and sex of the specimens were unknown. All measurements were taken from external surface of inferior aspect of the skull by using digital calipers accurate to 0.01 mm. In right and left sides; the distances between the external acoustic meatus (EAM) and the following anatomical landmarks were measured: articular tubercle (AT); anterior margin of squamous suture (ASS); superior margin of squamous suture (SSS); posterior margin of squamous suture (PSS); end point of styloid process (SP); midpoints of pterygomaxillary fissure (PMF); foramen ovale (FO); foramen spinosum (FS); and of carotid canal (CC).The distances of the external acoustic meatus to the anatomical structures on the right and left sides were: EAM-SP; 24.24±3.19 mm, 23.16±3.17 mm; EAM-PMF; 46.56±4.51mm, 46.25±3.96 mm; EAM-FO; 27.57±2.87 mm, 28.70±2.85 mm; EAM-FS; 22.53±3.19 mm, 22.72±3.47 mm; EAM-CC; 17.35±3.56 mm, 17.19±3.39 mm; EAM-AT; 19.31±3.79 mm, 18.95±3.42 mm; EAM-ASS; 43.14±4.80 mm, 46.82±4.61 mm; EAM-SSS; 49.17±4.74 mm, 48.83±3.34 mm and EAM-PSS; 36.15±4.24 mm, 35.39±4.25 mm, respectively. We think that the findings obtained from this study related to external acoustic meatus can be an important reference for surgical anatomy and surgical procedures in skull base.

RESUMEN: Las cirugías relacionadas con la base del cráneo son un desafío, las cuales requieren puntos de referencia anatómicos confiables. Existe una falta de conocimiento sobre las variaciones anatómicas en esta región. El objetivo de este estudio fue determinar los puntos de referencia extracraneales seguros para el abordaje quirúrgico de la base del cráneo. En este estudio se evaluaron 23 cráneos secos adultos: se desconocía la edad y el sexo de los ejemplares. Las medidas se tomaron de la superficie externa de la cara inferior del cráneo utilizando calibradores digitales con una precisión de 0,01 mm. En lados derecho e izquierdo se midieron las distancias entre el meato acústico externo (MAE) y los siguientes puntos de referencia anatómicos: tubérculo articular (TA); margen anterior de la sutura escamosa (MASE); margen superior de sutura escamosa (MSSE); margen posterior de sutura escamosa (MPSE); punto final del proceso estiloides (PFPE); puntos medios de la fisura pterigomaxilar (PMFP); foramen oval (FO); foramen espinoso (FE); y del canal carotídeo (CC). Las distancias del meato acústico externo a las estructuras anatómicas de los lados derecho e izquierdo fue- ron: MAE-PFPE; 24,24 ± 3,19 mm, 23,16 ± 3,17 mm; MAE-PMFP; 46,56 ± 4,51 mm, 46,25 ± 3,96 mm; MAE-FO; 27,57 ± 2,87 mm, 28,70 ± 2,85 mm; MAE-FE; 22,53 ± 3,19 mm, 22,72 ± 3,47 mm; MAE-CC; 17,35 ± 3,56 mm, 17,19 ± 3,39 mm; MAE-TA; 19,31 ± 3,79 mm, 18,95 ± 3,42 mm; MAE-MASE; 43,14 ± 4,80 mm, 46,82 ± 4,61 mm; MAE-MSSE; 49,17 ± 4,74 mm, 48,83 ± 3,34 mm y MAE-MPSE; 36,15 ± 4,24 mm, 35,39 ± 4,25 mm, respectivamente. Creemos que los hallazgos obtenidos de este estudio relacionados con el meato acústico externo pueden ser una referencia importante para la anatomía quirúrgica y los procedimientos quirúrgicos en la base del cráneo.