Primary jugular foramen fibrous dysplasia: surgically nuanced video of extradural infratemporal transjugular approach. Illustrative case.

BACKGROUND: Fibrous dysplasia of the bone is a disease caused by a somatic GNAS mutation that affects craniofacial bones and can have a mass effect on different neurovascular structures. The authors present the first case of primary jugular foramen fibrous dysplasia with occlusion of the transverse and sigmoid sinuses. OBJECTIVE: A 33-year-old man presented with a history of dizziness and occasional dysphagia over the past year. Magnetic resonance imaging showed a uniform enhanced mass in the left jugular foramen, with complete blockage of the adjacent transverse and sigmoid sinuses. The computed tomography scan revealed a cystic bone lesion of the jugular foramen. The patient underwent a gross-total removal of the tumor through an infratemporal transjugular approach with complete preservation of the lower cranial nerves. LESSONS: This first reported case of primary jugular foramen fibrous dysplasia highlights the importance of considering this diagnosis when evaluating jugular fossa lesions. Understanding the anatomy of the infratemporal and jugular fossae, along with proficiency in microsurgical techniques, is essential for removing such tumors while preserving cranial nerve functions and the patient's quality of life. https://thejns.org/doi/10.3171/CASE24396.

Anatomical Basis of the Zygomatic-Transmandibular Approach: Operative Video.

Tumor growth in infratemporal fossa (ITF) and parapharyngeal space (PPS) is generally slow and generates very few clinical manifestations, so it is not uncommon for tumors to reach large dimensions at the time of diagnosis, making necessary to perform ample approaches. In zygomatic-transmandibular approach (ZTMA), the access of the ITF and PPS is obtained by a combination of a pterional craniotomy plus a zygomatic-mandibular osteotomy. Tumor excision is achieved by its initial dissection from all of the neurovascular structures of the middle fossa by the neurosurgical team and the final resection by the head and neck team from below. In the first part of this video, we present a brief anatomical-surgical description of the ITF and PPS and in the second part, we show case of a trigeminal schwannoma that could be successfully removed through a ZTMA. Using this approach, an ample and safe exposure of the ITF and PPS is achieved, without affecting the chewing or facial nerve function and with excellent cosmetic results, so it can be considered as a reliable surgical option, particularly in cases of giant tumors that affect these regions ( Figs. 1 and 2 ). The link to the video can be found at: https://youtu.be/oxVFhzT8HsQ .

Remoción diferida de un tercer molar superior impulsado a la región infratemporal / Deferred removal of a third upper molar driven to the infratemporal region

La cirugía de los terceros molares retenidos puede ser considerada una intervención de rutina para el cirujano bucomaxilofacial. Como todo procedimien-to quirúrgico, puede presentar complicaciones intra y postoperatorias. Las más frecuentes son el dolor, edema, trismus, hemorragia y fracturas de las piezas dentarias a extraer, o de las tablas óseas. Pero tam-bién se pueden presentar otras complicaciones ines-peradas, como la impulsión o desplazamiento de la pieza dentaria a espacios anatómicos vecinos, entre los que podemos encontrar al espacio pterigomandi-bular, la celda submaxilar, el seno maxilar, el espacio infratemporal, según se trate de terceros molares retenidos inferiores o superiores. En el presente ar-tículo, se describe una situación clínica de un tercer molar superior, que fue accidentalmente impulsado a la región infratemporal, y removido en una segunda cirugía realizada 3 semanas después del primer in-tento de exodoncia. Se analizan también los estudios preoperatorios para su correcto diagnóstico, y las maniobras clínicas e instrumentales tendientes a po-sibilitar su remoción minimizando las complicaciones intra y postquirúrgicas (AU)

Surgery of retained third molars can be considered a routine intervention for the oral surgeon. Like any surgical procedure, it can present intra and posto-perative complications. The most frequent are pain, edema, trismus, hemorrhage and fractures of the teeth to be extracted or of the bone tables. But other unexpected complications can also occur, such as the impulsion or displacement of the tooth to neighbo-ring anatomical spaces, among which we can find the pterygomandibular space, the submaxillary cell, the maxillary sinus, the buccal space, the infratemporal space and the lateral pharyngeal space, depending on whether they are lower or upper retained third mo-lars. In this article, the clinical case of a third upper molar is described, which was accidentally driven to the infratemporal region, which was removed in a second surgery performed 3 weeks after the first attempt at exodontics. It should be noted the impor-tance of diagnostic imaging as an indispensable com-plement to the correct location of the displaced tooth and its subsequent removal (AU)

Condylar Dislocation for Intracranial Fossa: a Review of the Last 10 Years

The displacement of the mandibular condyle into the cranial fossa is an uncommon event; when it occurs, there is a need for immediate and multidisciplinary surgical intervention. Due to its rare advent, there is still no consolidated service dynamics, as this condition has not yet been described in a sedimented way in the literature databases. In the present article, we performed a literature review of condylar dislocation for the intracranial fossa described in the past 10 years in the PubMed and Lilacs search databases.

Desplazamiento de Tercer Molar Superior a Fosa Infratemporal: reporte de Casos y Revisión de Literatura / Maxillary Third Molar Displacement into the Infratemporal Fossa: case Report and Literature Review

RESUMEN: Dentro de las complicaciones transoperatorias de una cirugía de tercer molar se encuentra el desplazamiento del diente a espacios anatómicos adyacentes. Dicho accidente representa un porcentaje muy bajo de las complicaciones y se atribuye a una planeación y manejo clínico inadecuado. En este reporte se abordará específicamente el desplazamiento accidental de terceros molares superiores a la fosa infratemporal. Se realizó una búsqueda de información en la plataforma PubMed con las palabras claves "third molar displacement", obteniendo un total de 22 artículos según los criterios de inclusión. Se presentan dos casos de desplazamiento de tercer molar superior a fosa infratemporal manejados en el Centro Académico de Atención Odontológica (CAAD) del Tecnológico de Monterrey. El propósito del presente escrito es proponer un protocolo de manejo para dicha complicación.

ABSTRACT: One of the intraoperative complications of third molar surgery is the displacement of the tooth to adjacent anatomical spaces. This accident represents a small percentage of complications and is attributed to inadequate clinical planning and management. This report will specifically address the accidental displacement of upper third molars to the infratemporal fossa. A search was conducted by using the PubMed database with the keywords "third molar displacement", a total of 22 articles were included according to the inclusion criteria. Two cases of displacement of the upper third molar to the infratemporal fossa managed at the Centro Academico de Atencion Odontologica (CAAD) of the Tecnologico de Monterrey will be reported. The aim of this paper is to present a management protocol for this complication.

Cauterización transoral de la arteria maxilar interna en la fosa infratemporal: informe de un caso / Transoral cauterization of the internal maxillary artery in the infratemporal fossa: case report

Se describe el caso clínico de una paciente de 84 años que tuvo epistaxis recidivante por padecer enfermedad de Rendu-Osler-Weber. Tuvo antecedentes de diversos tratamientos quirúrgicos que incluyeron el cierre de la fosa nasal izquierda (operación de Young). Por la persistencia de epistaxis izquierda se indicó una angiografía y embolización. Esta última no se hizo porque se diagnosticaron anastomosis entre el sistema carotídeo externo y el interno. Se realizó un abordaje intraoral paramaxilar asistido con endoscopios para cauterizar la arteria maxilar interna en la fosa infratemporal y un abordaje externo para cauterizar la arteria etmoidal anterior solucionando la epistaxis. (AU)

The clinical case of an 84-year-old patient who had recurrent epistaxis due to Rendu-Osler- Weber disease is described. She had a history of various surgical treatments including closure of the left nostril (Young's operation).Due to the persistence of left epistaxis, angiography and embolization were indicated. The latter was not done because anastomosis between the external and internal carotid system was diagnosed. An intraoral paramaxillary approach assisted with endoscopes was performed to cauterize the internal maxillary artery in the infratemporal fossa and an external approach to cauterize the anterior ethmoidal artery solving the epistaxis. (AU)

Preservation of the facial and lower cranial nerves in glomus jugulare tumor surgery: modifying our surgical technique for improved outcomes.

PURPOSE: To describe the neurological results obtained in six patients with large Fisch C glomus jugulare tumors (GJT) in which a less aggressive, nerve-preserving surgical strategy was used to reduce surgical morbidity. METHODS: Prospective study of six patients with Fisch C GJT who underwent surgery in a tertiary care referral center from February 2015 to August 2017 with an average follow-up of 18 months. The intervention is the surgical technique used and the main outcome measures are recurrence and the functional preservation of the facial and lower cranial nerves. RESULTS: Gross total removal was obtained in the six patients with preservation of the medial wall of the jugular bulb protecting the lower cranial nerves. After follow-up, we obtained a House-Brackmann (H-B) grade II in three patients who were managed with an inferior facial nerve transposition. One patient managed with a facial bridge technique preserved a normal facial function and two patients who presented a H-B III before surgery went to H-B V after surgery and recovered to a H-B III after 4 months. Four patients were presented with dysphagia after surgery and required nasogastric tube placement. The average time for removal with return to normal oral feeding was 4.3 weeks. Three patients with preoperative Xth nerve dysfunction showed an adequate compensation of the opposite vocal fold in the postoperative period without dysphonia or aspiration. CONCLUSION: The surgical techniques used in these patients provided good functional preservation without recurrence after an 8-30-month follow-up.

Unusual origin and relations of the accessory meningeal artery: a case report / Origen inusual y relaciones de la arteria meníngea accesoria: reporte de un caso

SUMMARY: Accessory meningeal artery is a branch of the first part of the maxillary artery. It supplies the structures in the infratemporal fossa and the dura mater in the middle cranial fossa. Accessory meningeal artery arose from the middle meningeal artery, 25 mm below the base of the skull and entered the middle cranial fossa through the foramen ovale. The two roots of the auriculotemporal nerve looped around it. The knowledge of the variant origin and relations may be useful during the surgeries of the infratemporal fossa. It might also be useful to the radiologists.

RESUMEN: La arteria meníngea media es una rama accesoria que emerge al inicio de la arteria maxilar. Suministra la vascularización a nivel de la fosa infratemporal y la duramadre en la fosa craneal media. En este trabajo, surgió una arteria meníngea accesoria de la arteria meníngea media, a una 25 mm por debajo de la base del cráneo, accediendo en la fosa craneal media a través del foramen oval. Las dos raíces del nervio auriculotemporal la rodeaban. El conocimiento de esta variación y sus relaciones pueden ser útiles durante las cirugías de la fosa infratemporal, como así también puede ser útil para los radiólogos.

Frequency and characterization of the infratemporal spine in a sample of Chilean human skulls / Frecuencia y caracterización de la espina infratemporal en una muestra de cráneos humanos chilenos

The infratemporal spine, or sphenoidal tubercle, is a bony structure described in both classical anatomical literature and contemporary literature. However, the available literature does not mention the specific anatomical characteristics or the distribution of this bony element in the population. The aim of this study was to define this structure, identify its presence, and identify its morphology in a sample of Chilean human skulls. Fifty-seven dry skulls, obtained from the morphology unit at Universidad de los Andes, were used. The great wings of the sphenoid bone on both sides of the skull were evaluated in search of the infratemporal spine. These spines were classified according to their morphological characteristics of either laminar, pyramidal, or truncated pyramidal, as they related to the infratemporal crest and as they related to the pterygoid process. The presence of the infratemporal spine was found in 100 % of the studied skulls, unilaterally or bilaterally. The most common morphology was found to be laminar (40 %), followed by pyramidal (35 %), and, finally, truncated pyramidal (24 %). The majority (73 %) of these infratemporal spines was closely associated with the pterigoyd process with a complete or partial relation, with fewer (34 %) being associated with the infratemporal crest.

La espina infratemporal o tubérculo esfenoidal es un reparo óseo mencionado tanto en la literatura anatómica clásica como en los artículos más actuales. Las publicaciones disponibles no mencionan las características anatómicas ni la distribución en la población de este elemento óseo. El objetivo de este trabajo fue definir, identificar la presencia y describir la morfología de la espina infratemporal en una muestra de población chilena. Se utilizaron 57 cráneos secos de la unidad de anatomía de la Universidad de los Andes. Se evaluaron las alas mayores del hueso esfenoides tanto derechas como izquierdas en búsqueda de la espina infratemporal. Se clasificaron según sus características morfológicas, siendo piramidal, piramidal truncada o laminar, según su relación con la cresta infratemporal y según su relación con el proceso pterigoideo. Se encontró la presencia de la espina infratemporal en un 100 % de los cráneos estudiados, ya sea de manera uni o bilateral. La morfología más común correspondió a laminar con un 40 %, seguido de piramidal con un 35 % y finalmente un 24 % de morfología piramidal truncada. Se relacionaron más bien con el proceso pterigoideo ya sea de manera completa o media (73 %) y en menor medida con la cresta infratemporal (34 %).

Surgical treatment of projectile in the infratemporal fossa. Case report / Tratamento cirúrgico de um projétil na fossa infratemporal. Relato de caso

ABSTRACT BACKGROUND AND OBJECTIVES: Gunshot wounds may have fatal results. Even when not causing major injuries to soft and hard tissues, there may be other severe problems. This study aimed at reporting the case of a projectile located in the left infratemporal fossa and at discussing treatment, risks and complications. CASE REPORT: Male patient, 18 years old, suffered a gunshot wound which has penetrated the face by the left zygomatic region, and was lodged in the homolateral infratemporal fossa. This has caused jaw function impairment and pain. Foreign body was surgically removed by preauricular access and patient was then submitted to physiotherapy. After treatment, temporomandibular joint function was reestablished and esthetic results were considered excellent without sequelae. CONCLUSION: Management of patients hit by projectiles is more complex when these are located in an area of difficult access and close to noble structures. Radiographic techniques obtained by means of different planes allow the accurate location of the object. There may be major deformity and functional incapacity, especially if the facial nerve is affected during bullet trauma or during surgery. Although there were no nervous injuries, functional impairment of orofacial structures was decisive to indicate the surgical procedure. Surgical removal of the projectile from the infratemporal fossa, combined with postoperative physiotherapy, has shown to be an effective treatment.

RESUMO JUSTIFICATIVA E OBJETIVOS: Ferimentos causados por arma de fogo podem ter resultados fatais. Mesmo que a bala não cause grandes lesões para os tecidos moles e duros, outros problemas graves podem ocorrer. O objetivo deste estudo foi relatar o caso de um projétil localizado na fossa infratemporal esquerda, discutir o tratamento cirúrgico, seus riscos e complicações. RELATO DO CASO: Paciente do gênero masculino, 18 anos, sofreu um ferimento por arma de fogo que penetrou na face pela região zigomática esquerda, alojando-se na fossa infratemporal homolateral. Esse ocasionou comprometimento da função mandibular e dor. O corpo estranho foi removido cirurgicamente por meio do acesso pré-auricular e o paciente foi posteriormente submetido a sessões de fisioterapia. Após o tratamento, foi reestabelecida a função da articulação temporomandibular, a dor desapareceu e os resultados estéticos foram considerados excelentes, sem sequelas. CONCLUSÃO: O manuseio dos pacientes acometidos por projétil torna-se mais complexo quando esse está localizado em uma área de difícil acesso e ao lado de estruturas nobres. Técnicas radiográficas, obtidas por meio de diferentes planos, permitem uma localização precisa do objeto. Grande deformidade e incapacidade funcional podem ocorrer, especialmente, se o nervo facial é afetado durante o trauma balístico ou durante o ato cirúrgico. Apesar de não haver lesões nervosas, o comprometimento funcional das estruturas orofaciais foi decisivo para indicar o procedimento cirúrgico. A remoção cirúrgica do projétil da fossa infratemporal combinado com a fisioterapia, pós-operatória, mostraram ser um tratamento eficaz.

Eliminación quirúrgica de tercer molar desde la fosa infratemporal por trismus severo / Surgical removal from third molar infratemporal maxillary by severe trismus

La limitación severa de la apertura bucal, Trismus corresponde a un cuadro clínico que puede tener etiología diversa. En este caso, nos referiremos a un paciente de género femenino, de 42 años de edad, que acude al Servicio de Cirugía Máxilofacial del Hospital del Trabajador de Santiago de Chile, quien consulta por un cuadro de limitación severa de la apertura bucal (8 mm.) de 5 años de evolución. Relata atenciones previas e intentos de eliminación quirúrgica del tercer molar superior izquierdo, lo cual no asocia a su limitación de apertura. Informa que ha recibido terapia kinésica, sin resultados favorables. Se realizan exámenes imagenológicos, distinguiéndose la presencia de un molar ectópico a nivel de la fosa infratemporal izquierda, bajo el arco cigomático y en relación con la apófisis coronoides ipsilateral. Se planifica la eliminación quirúrgica quirúrgica del cuerpo extraño mediante un abordaje intraoral bajo anestesia general. Se presenta el caso incluyendo el tratamiento quirúrgico y su evolución hasta la séptima semana del postoperatorio.

Unilateral variation in the origin of the inferior alveolar and buccal arteries: a case report / Variación unilateral en el origen de las arterias alveolar inferior y bucal: reporte de un caso

The maxillary artery (MA) is one of the terminal branches of the external carotid artery (ECA) and is located in the infratemporal fossa (IF). Some of the branches in this region are the inferior alveolar artery (IAA) and the buccal artery (BA), both descending branches. Here, we report an unusual unilateral origin of the IAA and the BA from a common trunk directly from the ECA. We conducted a routine dissection of both IF in a 54-year-old hispanic male cadaver. Fixed with Universidad de los Andes® conservative solution and red latex for vascular filling. On each side, the MA is observed superficially located over the lateral pterygoid muscle. On the right side, the IAA and the BA originate from a common trunk from the ECA approximately 5 mm prior to the bifurcation into their terminal branches. On the left side, the IAA originates from the MA that is immediately next to its origin, making a common trunk with the pterygoid branches. Knowing the morphology of the MA and its branches at the IF is important for oral and maxillofacial surgery procedures; and any variation in the origin or course of these arteries may result in the patient's increased morbidity during some invasive procedure in the area.

La arteria maxilar (AM) es una rama terminal de la arteria carótida externa (ACE), y se ubica en la región infratemporal (RI). Algunas de sus ramas en esta región son la arteria alveolar inferior (AAI) y la arteria bucal (AB), ambas ramas descendentes. En este trabajo informamos de un inusual origen unilateral de la AAI y de la AB a partir de un tronco común desde la ACE. Se realizó una disección de rutina de ambas regiones infratemporales en un cadáver de 54 años, sexo masculino, caucásico. Fijado con solución conservadora Universidad de los Andes® y repleción vascular con látex rojo. A cada lado, se observa la AM en ubicación superficial sobre el músculo pterigoideo lateral. Al lado derecho, la AAI y la AB se originan de un tronco común desde la ACE aproximadamente 5 mm antes de la bifurcación en sus ramas terminales. Al lado izquierdo la AAI se origina de la AM inmediato a su origen, formando un tronco común con los ramos pterigoideos. El conocimiento de la morfología de la AM y de sus ramas en la RI es de importancia en procedimientos odontológicos, de cirugía oral y maxilofacial. Por lo que cualquier variación en el origen o trayecto de estas arterias puede predisponer a un paciente a una mayor morbilidad durante algún procedimiento invasivo en la zona.

Anatomical study of the pterygospinous and pterygoalar bony bridges and foramens in dried crania and its clinical relevance / Estudio anatómico de los puentes óseos y forámenes pterigoespinoso y pterigoalar en cráneos secos y su relevancia clínica

The ossification of the intrinsic ligaments of the sphenoid bone has been reported in the literature. The presence of bony bridges by ossification of the pterygospinous and pterygoalar ligaments has clinical significance in the infratemporal fossa contents. The purpose of this study is to analyze the prevalence of ossification of these ligaments and assess morphometrically the pterygospinous (Civinini's) and pterygoalar (crotaphitico-buccinatorius) foramens. A total of 312 human skulls from the collection of Universidade Federal de São Paulo (UNIFESP) were used to assess the presence of total or partial ossification in pterygospinous (Types I and II) and pterygoalar (Types III and IV) ligaments. Of the sample, 37.18 percent had some degree of ossification; in Type I, ossification was found in 1.6 percent, while Types II, III and IV had 13.14, 3.84, and 22.43 percent, respectively. The pterygospinous foramen presented an average diameter between 10.626ð7.366 mm, whereas for the pterygoalar foramen it was between 5.202ð3.793 mm. The presence of these formations must be considered in the therapeutic procedures that are performed in the infratemporal region, in assessing pain affecting the territory innervated by the mandibular nerve.

La osificación de los ligamentos intrínsecos del hueso esfenoides ha sido reportada en la literatura. La presencia de puentes óseos por osificación de los ligamentos pterigoespinoso y pterigoalar tiene importancia clínica debido a las relaciones que éstas formaciones establecen con el contenido de la fosa infratemporal. El propósito de este estudio fue analizar la prevalencia de la osificación de estos ligamentos y evaluar morfométricamente los forámenes pterigoespinoso (Cinivini's) y pterigoalar (crotaphitico-buccinatorius). Se utilizaron 312 cráneos humanos de la colección de la UNIFESP, se evaluó la presencia de osificación total o parcial de los ligamentos pterigoespinoso (Tipos I y II) y pterigoalar (Tipos III y IV). Un 37,18 por ciento de la muestra presentó algún grado de osificación, el tipo I se encontró en un 1,6 por ciento por ciento, el tipo II en un 13,14 por ciento, el tipo III en un 3,84 por ciento por ciento y el tipo IV en un 22,43 por ciento. El foramen pterigoespinoso presentó un diámetro medio de entre 10,626 ð 7,366 mm, mientras que para el foramen pterigoalar estuvieron entre 5,202 ð 3,793 mm. La presencia de estas formaciones debe ser considerada en los procedimientos terapéuticos que se realicen en la región infratemporal y en la evaluación de cuadros dolorosos que afectan al territorio inervado por el nervio mandibular.

An unusual relationship between the inferior alveolar nerve, lingual nerve and maxillary artery / Una inusual relación entre los nervios alveolar inferior y lingual y la arteria maxilar

The knowledge of the neurovascular relationships of the infratemporal region is relevant in odontostomatology practice. In this article we present a case of atypical communication between the inferior alveolar nerve and lingual nerve associated with a change in relations with the maxillary artery, and discusses some clinical implications that these relations have on the development of the suplementary innervation and the anesthesia.

El conocimiento de las relaciones entre los elementos neurovasculares de la región infratemporal es relevante en la práctica odontoestomatológica. En el presente artículo presentamos el caso de una comunicación atípica entre el nervio alveolar inferior y el nervio lingual asociados a una variación en las relaciones con la arteria maxilar, y sediscut en algunas implicancias clínicas que estas relaciones tienen en el desarrollo de inervación suplementaria y en la práctica anestésica.

Estudio Anatómico en Relación a los Sitios Comprometidos en la Técnica de Implantes Cigomáticos / Anatomical Study in Relation to the Implicated Sites in the Zygomatic Implants Technique

La técnica de implantes cigomáticos fue introducida por Branemark et al. (1997) en la búsqueda de una solución simple para pacientes desdentados totales de maxilares sin reborde residual. La tasa de éxito comunicada por estos autores fue de 96.5%. La técnica descrita Branemark et al. comienza a nivel de la zona palatina de los 2º premolares, cruzando el reborde alveolar hacia el seno maxilar y a través de éste hacia el borde postero superior del hueso cigomático (ángulo yugal), logrando la estabilización del implante a ese nivel. La presente investigación se realizó en cráneos completos del Departamento de Anatomía Humana de la Facultad de Odontología de la Universidad Mayor, en los cuales se efectuaron mediciones bilaterales de las diferentes estructuras óseas comprometidas en el recorrido del implante cigomático, con el propósito de determinar el recorrido intraóseo de este tipo de implante y su relación con las estructuras que atraviesa. Independiente del tipo de cráneo analizado, la relación de contacto hueso- implante en el recorrido de éste, es de aproximadamente un tercio de su longitud y así se tiene que en distancias promedio de 40 mm de recorrido, no más de 10 a 12 mm de tejido óseo están en contacto con el implante.

The technique of zygomatic implants introduced by Branemark et al. (1997) in search of a simple solution for total maxillary toothless patients without a residual margin. The rate of success communicated by these authors was of 96.5%. The technique Branemark et al. describes, begins at the level of the palatine area of the 2° premolars crossing the alveolar margin toward the maxillary sinus and throughout the same toward the posterosuperior margin, obtaining the stabilization of the implant at that level. The present investigation was realized in complete cranium of the Department of Human Anatomy of the Dentistry Department of the Universidad Mayor, S antiago, Chile, during which bilateral measurements of the different bone structures affected in the zygomatic implant, with the purpose of determining the intra bone trajectory in this type of implant and its relation with the structures that it crosses. Independently of the type of cranium analyzed, the relation of the bone-implant contact in itstrajectory, is approximately one third of its longitude and it is determined that in an average distance of 40 mm or trajectory, no more than 10 to 12 mm of bone tissue is in contact with the implant.