[An anatomical road map of the parapharyngeal internal carotid artery in lateral and endoscopic ventral approaches].

Objective:To describe the road map of the lateral and endoscopic ventral approaches for the pharyngeal segment of the internal carotid artery, propose a sub-segmentation scheme, systematically and comprehensively understand its anatomical details and relationships with the surrounding structures. Methods:Five fresh cadaveric head specimens（10 sides in total） were dissected through lateral and endoscopic ventral approaches to evaluate the anatomical details of the parapharyngeal internal carotid artery and its relationship with the surrounding structures. Results:From the bifurcation of the common carotid artery to the vertical part of the internal carotid artery, alongside the direction of blood flow, the parapharyngeal internal carotid artery passes through four distinct anatomical tissues. Based on this, the parapharyngeal internal carotid artery can be divided into four sub-segments: nerve, muscle, fascia and osseous sub-segments. The boundaries and important adjacent structures of each segment are described in detail. Conclusion:The anatomical road map of the parapharyngeal internal carotid artery and the sub-segmentation scheme serving as a practical guide to navigate modular endoscopic skull base surgery of the parapharyngeal space while reduce the risk of internal carotid artery injury.

[Research progress in the anatomy and surgical approach of the parapharyngeal space].

The parapharyngeal space, a complex fascial compartment within the head and neck region, encompasses crucial anatomical structures including blood vessels and nerves. Tumors occurring within this space are rare, with the majority being benign in nature. Surgical intervention remains the primary treatment modality; however, managing parapharyngeal space tumors poses significant challenges due to their intricate anatomical configuration. Conventional open surgical approaches have been associated with significant tissue damage and a high prevalence of postoperative complications. Recently, advancements in anatomical studies and surgical techniques have led to significant progress in understanding parapharyngeal space anatomy and improving surgical management. This article aims to provide a comprehensive overview of these developments.

Quantitative Prediction of the Location of Carotid Bifurcation and Neurovascular Structures in the Carotid Region: A Cross-Sectional Cadaveric Study.

INTRODUCTION: The carotid region is encountered in vascular and neurological surgery and carries a potential for vascular and cranial nerve trauma. The carotid bifurcation is an especially important landmark and difficult to predict based on currently established landmarks. This study is a detailed analysis of the carotid region and proposes a novel methodology to predict the height of the bifurcation. MATERIALS AND METHODS: Superficial and deep dissections were performed on the anterior triangle of the neck to expose the carotid region in twenty-one formalin-fixed donor cadavers. Musculoskeletal and neurovascular structures were assessed in relation to the carotid bifurcation and the medial border of the clavicle (MBC). RESULTS: The carotid bifurcation occurred, on average, 11.4 mm higher on the left (p < 0.001; 95% CI: 9.28, 13.54). The superior thyroid artery (p < 0.001), facial vein (p < 0.001), and cranial nerve XII (p < 0.001) were all more distal on the left side when measured from the MBC while the angle of the mandible and stylohyoid muscle remained symmetric. Left- and right-sided vascular structures were symmetric when measured from the carotid bifurcation. CONCLUSIONS: Neurovascular structures within the carotid region are likely to be anatomically superior on the left side while vessels are likely to remain symmetric in relation to the carotid bifurcation. When measured from the MBC, the bifurcation height can be predicted by multiplying the distance between the MBC and mastoid process by 0.65 (right side) or 0.74 (left side). This novel methodological estimation may be easily learned and directly implemented in clinical practice.

Endoscopic Endonasal Approach to the Ventral-Medial Portion of Posterior Paramedian Skull Base: A Morphometric Perspective of Surgical and Radiologic Anatomy.

OBJECTIVE: This study aims to provide morphometric analysis of endoscopic endonasal approach (EEA) to the ventral-medial portion of posterior paramedian skull base. Furthermore, it aims to investigate the surgical exposure obtained through EEA with and without eustachian tube (ET) removal, emphasizing the role of contralateral nostril (CN) access. METHODS: Five fresh adult head specimens were prepared for dissection. A predissection and a postdissection computed tomography study was performed. A surgically oriented classification into 4 regions was used: 1) tubercular region; 2) occipital condyle region; 3) parapharyngeal space (PPhS) region; and 4) jugular foramen (JF) region. The Student t-test was used to compare angulations and measures of EEA with access from the ipsilateral and CN, respectively, with and without ET removal. RESULTS: EEA to the ventral-medial portion of posterior paramedian skull base encompasses 2 medial trajectories (transtubercular and transcondylar) and 2 lateral pathways to the PPhS and JF. The CN access, without removal of the ET, allows a complete exposure of the petrous and intrajugular portion of the JF and superior PPhS without exposition of the parapharyngeal segment of internal carotid artery. The ipsilateral nostril approach with ET removal allows to obtain a wider exposure, reaching the medial sigmoid part of the JF. No significant differences exist in regard to transtubercular and transcondylar approaches. CONCLUSIONS: This study suggests that EEA to posterior paramedian skull base allows the realization of a corridor directed to the jugular tubercle, occipital condyle, medial PPhS, and ventral-medial JF. The CN approach with ET preservation can expose the petrous and intrajugular parts of the JF and PPhS. Case series are needed to demonstrate benefits and drawbacks of these approaches.

Surgical anatomy and nuances of the expanded transpterygoid approach to the pterygopalatine fossa and upper parapharyngeal space: a stepwise cadaveric dissection.

BACKGROUND: Superb knowledge of anatomy and techniques to remove the natural barriers preventing full access to the most lateral aspect of the skull base determines the ease of using the transpterygoid approach (ETPA) as the main gateway for all the coronal planes during endonasal surgeries. METHODS: Throughout stepwise image-guided cadaveric dissections, we describe the surgical anatomy and nuances of the ETPA to the pterygopalatine fossa (PPF) and upper parapharyngeal space (UPPS). CONCLUSION: The ETPA represents a lateral extension of the midline corridor and provides a valuable route to access the PPF/UPPS. Major landmarks for this EEA are the infraorbital canal, sphenopalatine foramen, and vidian nerve. It comprises the removal of the palatine bone, posterior wall of the maxillary sinus, and PPF transposition to drill the pterygoid process.

Preauricular retromandibular trans tympanic plate and styloid process keyhole approach to parapharyngeal lesions: a laboratory study.

BACKGROUND: The surgical removal of the infratemporal parapharyngeal lesions (IPL) is challenging due to its anatomical complexity. Previous surgical approaches have often been too invasive and necessitated sacrifice of normal function and anatomical structures, particularly in the retromandibular nerve region. Therefore, we sought to identify an approach corridor to this area that requires less sacrifice and report an innovative approach through a retromandibular fossa route to the IPL. METHODS: Five cadaveric specimens were dissected bilaterally with a trans-tympanic plate and styloid process approach. These specimens were investigated microanatomically and morphometrically to examine the extent of the approach in the parapharyngeal space. The clinical application of this approach was compared to previous approaches to the IPL used in our clinical series of 20 cases. RESULTS: Using this novel approach, the inferior alveolar nerve was identified in all specimens, while the chorda tympani and lingual nerve were identified in 6 (60%) and 4 (40%) dissections, respectively. In all specimens, the petrous portion of the internal carotid artery and the exit of the lower cranial nerve were identified. The average length of the exposed lower cranial nerves was 16.6 ± 3.8 mm (range: 11-25 mm). CONCLUSIONS: The described approach is feasible for accessing the IPL at the retromandibular nerve and is less invasive than conventionally used approaches.

Endoscopic transnasal transmaxillary approach to the upper parapharyngeal space and the skull base.

PURPOSE: Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application. METHODS: Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS. RESULTS: The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery. CONCLUSIONS: Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS.

Characterization of Anatomical Landmarks for Exposing the Internal Carotid Artery in the Infratemporal Fossa Through an Endoscopic Transmasticator Approach: A Morphometric Cadaveric Study.

BACKGROUND: The Eustachian tube and sphenoid spine have been previously described as landmarks for endonasal surgical identification of the most distal segment of the parapharyngeal internal carotid artery (PhICA). However, the intervening space between the sphenoid spine and PhICA allows for error during exposure of the artery. In the present study, we have characterized endoscopic endonasal transmasticator exposure of the PhICA using the sphenoid spine, vaginal process of the tympanic bone, and the "tympanic crest" as useful anatomical landmarks. METHODS: Endonasal dissection was performed in 13 embalmed latex-injected cadaveric specimens. Two open lateral dissections and osteologic analysis of 10 dry skulls were also performed. RESULTS: A novel and palpable bony landmark, the inferomedial edge of the tympanic bone, referred to as the tympanic crest, was identified, leading from the sphenoid spine to the lateral carotid canal. Additionally, the vaginal process of the tympanic bone, viewed endoscopically, was a guide to the PhICA. The sphenoid spine was bifurcate in 20% of the skulls, with an average length of 5.98 mm (range, 3.9-8.2 mm), width of 5.81 mm (range, 3.0-10.6 mm), and distance to the carotid canal of 4.48 mm (range, 2.5-6.1 mm). CONCLUSION: The sphenoid spine and pericarotid space has variable anatomy. Using an endoscopic transmasticator approach to the infratemporal fossa, we found that the closest landmarks leading to the PhICA were the tympanic crest, sphenoid spine, and vaginal process of the tympanic bone.

Surgical anatomy of the parapharyngeal space: Multiperspective, quantification-based study.

BACKGROUND: Several surgical approaches to the parapharyngeal space (PPS) have been proposed. An objective description of advantages and limitations of the surgical routes is lacking. METHODS: Ten cadaver heads were dissected using the transnasal (medial, lateral), sublabial, transoral (transpharyngeal, transvestibular, transmandibular), transcervical (transcervical, transparotid, transmandibular, transmastoid), and type C and D infratemporal approaches. Neurovascular and musculoskeletal structures encountered were analyzed. A navigation-based quantification of working volume and exposure of PPS compartments was accomplished. RESULTS: Transnasal approaches exposed the upper PPS, though with limited working volume. Transoral approaches exposed the middle PPS, minimizing neurovascular structures crossed. Only transcervical and skull base approaches exposed the entire PPS, crossing several neurovascular structures. CONCLUSION: A tentative systematization of the surgical approach(es) to PPS in relation to different targets is provided: unicompartmental resection can be performed with a single, conservative access, whereas multicompartmental dissections frequently require a wider or multiportal approach.

Resección transoral-transnasal de tumores del espacio parafaríngeo / Transoral-transnasal approach to parapharyngeal space tumors

Objetivos: Determinar la tasa de resección quirúrgica completa en tumores seleccionados del Espacio parafaríngeo tratados por vía transoral o transnasal o por ambas. Diseño: descriptivo, retrospectivo. Materiales y métodos: Se incluyeron en este estudio los pacientes que tuvieron neoplasias localizadas en el espacio parafaríngeo y que fueron tratados con cirugía por vía transoral o transnasal. El abordaje transoral consistió en realizar una incisión con cauterio en la zona de mayor protrusión del tumor (pilar amigdalino y paladar), disección de la mucosa y del tumor de los planos profundos, traccionándolo hacia la cavidad oral. Para disecar el límite superior (rinofaringe) y lateral se utilizaron endoscopios que fueron introducidos por la incisión y por la cavidad nasal. El abordaje transnasal consistió en realizar una incisión en la pared lateral de la rinofaringe y disecar el tumor del plano profundo traccionándolo hacia el cavum. Resultados: Fueron tratados 3 pacientes por vía transoral y uno por vía endonasal por padecer tumores del espacio parafaríngeo. Tres tumores se originaron en glándulas salivales menores localizadas una en el espacio. Preestiloideo (1/3), otra en el espacio masticador (1/3) y otra en el sector superior del espacio preestiloideo (1/3). La histología dio como resultado dos adenoma pleomorfo y un carcinoma mucoepidermoide de bajo grado (1/3). (Está bien así? Qué es 1/3?). Una neoplasia se originó en el lóbulo profundo de la parótida y se extendió al espacio preestiloideo, su histología fue carcinoma mucoepidermoide de grado moderado. Conclusiones: La tasa de resección completa en pacientes con tumores del espacio parafaríngeo seleccionados tratados por vía transoral y endonasal fue del 100%. (AU)

Objectives: To determine the rate of complete surgical resection in parapharyngeal space selected tumors treated with transoral and / or transnasal approach. Design: Descriptive, retrospective. Materials and methods: Patients who had tumors localized in parapharyngealspace and who were treated with transoral or transnasal surgery. were included in this study. The transoral approach consisted in performing an incision with cautery in the area of greates tumor protrusion (tonsillar pillar and palate), dissection of the mucosa and tumor of the deep planes, pulling it into the oral cavity. To dissect the upper limit (nasopharynx) and lateral we used endoscopes that were inserted by the incision and the nasal cavity. The transnasal approach consisted in making an incision in the side wall of the nasopharynx and dissect the tumor of the deep plane pulling it towards the cavum. Results: Three patients were treated with transoral and one byendonasalapproacheswho had parapharyngeal space tumors. Three tumors originated in minor salivary glands located in prestyloidspace (1/3), masticator space (1/3) and upper sector of pree-styloid space (1/3). Histology was in two pleomorphic adenoma, and another onelow degree mucoepidermoid carcinoma (1/3). A neoplasm was originated in the deep lobe of the parotid gland and was extended to the prestyloid space, was a moderate degree of mucoepidermoid carcinoma. Conclusions: Complete resection rate in patients with selected parapharyngeal space tumors, treated by transorally and endonasal approach was 100%. (AU)