Transoral robotic surgery (TORS) provides a minimally invasive approach to address tumors in selected and challenging anatomical locations. Among the critical areas where TORS demonstrates its prowess is the oropharynx. Oropharyngeal tumors can invade parapharyngeal space (PPS) which contains vital structures such as the carotid artery, internal jugular vein, and cranial nerves IX-XII. A deeper understanding of the endoscopic anatomy of the parapharyngeal space could reduce the morbidity associated with tumor resection in this dense neurovascular area. This video-article provides a step-by-step cadaveric dissection of the lower PPS though a transoral robotic approach.

Backgrounds/Objectives: Parotid gland tumors (PGTs) with parapharyngeal space (PPS) involvement have a specific clinical course and they can be a great challenge for surgeons, especially due to more difficult approaches and the risk of serious complications. The aim of this study is to present the characteristics of PGTs with PPS involvement. Methods: Retrospective, multicenter analysis of 1954 primary PGTs from 5 years (2017-2021) was performed. Comparative analysis was performed between groups with and without PPS involvement and included the following clinical and histopathological data: age, sex, place of residence, tumor size, FNAC result, percentage of malignant tumors, histological diagnosis, radicality of resection, and postoperative facial nerve (FN) dysfunction. Results: PPS involvement was found in 114 patients (5.83%). Secondary tumors affecting the deep lobe or the entire gland were predominant (46 and 60 cases, respectively). In a univariate analysis of tumors with and without PPS involvement, statistically significant differences were found in their size > 4 cm (12.97% vs. 37.72%), percentage of malignant tumors (7.12% vs. 17.55%), incidence of Warthin Tumors (WTs) (43.58% vs. 24.56%), percentage of R1 resection (5.53% vs. 12.50%), and rate of FN paresis (17.15% vs. 53.34%). Multivariate analysis showed that tumors with PPS involvement were statistically significantly characterized by larger size (tumors > 4 cm were 2.9 times more frequent), 2 times less frequent occurrence of WTs, and 1.6 times higher risk of FN paresis. Conclusion: PGTs with PPS involvement show certain clinical and histological differences and require more complex surgical accesses. Therefore, they cannot be treated as \"ordinary\" tumors occupying the deep lobe.

OBJECTIVE: This study aimed to investigate whether multiparametric magnetic resonance imaging (MRI) including dynamic contrast-enhanced (DCE) and diffusion weighted (DW) MRI can differentiate pleomorphic adenoma (PA) from schwannoma in the parapharyngeal space.
METHODS: Forty-six patients with pathologically proven PAs and 47 schwannomas in the parapharyngeal space were enrolled. All patients underwent conventional MRI, and DW-MRI and DCE-MRI were performed in 30 and 33 patients, respectively. Fisher\'s exact, Mann-Whitney-U tests and Independent samples t-test were used to compare variables between PAs and schwannomas. Multivariate logistic regression analysis was used to examine the diagnostic performance of MRI parameters.
RESULTS: The PAs usually show lobulation sign, posterior displacement of ICA and attached to the parotid gland deep leaf, while bird beak configuration, anterior displacement of ICA and involvement of foramen jugular were more commonly seen in the schwannomas(all p < 0.001). The washout rate of PAs was found to be higher than that of schwannomas (p = 0.035), whereas no significance was found in the other DCE-MRI parameters and in ADCs(p > 0.05). Using a combination of conventional MRI features including lobulation sign, bird beak configuration, direction of internal carotid artery(ICA) displacement and attached to the parotid gland in multivariate logistic regression analysis, sensitivity, specificity, and accuracy in differential diagnosis of PAs and schwannomas were 97.8%, 91.5% and 94.6%, respectively.
CONCLUSIONS: Conventional MRI can effectively differentiate PAs from schwannomas in the parapharyngeal space with a high diagnostic accuracy. The DCE-MRI and DWI have limited added diagnostic value to conventional MRI in the differential diagnosis.

BACKGROUND: Computed tomography (CT) reconstruction algorithms can improve image quality, especially deep learning reconstruction (DLR). We compared DLR, iterative reconstruction (IR), and filtered back projection (FBP) for lesion detection in neck CT.
METHODS: Nine patient-mimicking neck phantoms were examined with a 320-slice scanner at six doses: 0.5, 1, 1.6, 2.1, 3.1, and 5.2 mGy. Each of eight phantoms contained one circular lesion (diameter 1 cm; contrast -30 HU to the background) in the parapharyngeal space; one phantom had no lesions. Reconstruction was made using FBP, IR, and DLR. Thirteen readers were tasked with identifying and localizing lesions in 32 images with a lesion and 20 without lesions for each dose and reconstruction algorithm. Receiver operating characteristic (ROC) and localization ROC (LROC) analysis were performed.
RESULTS: DLR improved lesion detection with ROC area under the curve (AUC) 0.724 ± 0.023 (mean ± standard error of the mean) using DLR versus 0.696 ± 0.021 using IR (p = 0.037) and 0.671 ± 0.023 using FBP (p < 0.001). Likewise, DLR improved lesion localization, with LROC AUC 0.407 ± 0.039 versus 0.338 ± 0.041 using IR (p = 0.002) and 0.313 ± 0.044 using FBP (p < 0.001). Dose reduction to 0.5 mGy compromised lesion detection in FBP-reconstructed images compared to doses ≥ 2.1 mGy (p ≤ 0.024), while no effect was observed with DLR or IR (p ≥ 0.058).
CONCLUSIONS: DLR improved the detectability of lesions in neck CT imaging. Dose reduction to 0.5 mGy maintained lesion detectability when denoising reconstruction was used.
CONCLUSIONS: Deep learning enhances lesion detection in neck CT imaging compared to iterative reconstruction and filtered back projection, offering improved diagnostic performance and potential for x-ray dose reduction.
CONCLUSIONS: Low-contrast lesion detectability was assessed in anatomically realistic neck CT phantoms. Deep learning reconstruction (DLR) outperformed filtered back projection and iterative reconstruction. Dose has little impact on lesion detectability against anatomical background structures.

UNASSIGNED: This study compared sequential changes in skeletal stability and the pharyngeal airway following mandibular setback surgery involving fixation with either a titanium or a bioabsorbable plate and screws.
UNASSIGNED: Twenty-eight patients with mandibular prognathism undergoing bilateral sagittal split osteotomy by titanium or bioabsorbable fixation were randomly selected in this study. Lateral cephalometric analysis was conducted preoperatively and at 1 week, 3-6 months, and 1 year postoperatively. Mandibular stability was assessed by examining horizontal (BX), vertical (BY), and angular measurements including the sella-nasion to point B angle and the mandibular plane angle (MPA). Pharyngeal airway changes were evaluated by analyzing the nasopharynx, uvula-pharynx, tongue-pharynx, and epiglottis-pharynx (EOP) distances. Mandibular and pharyngeal airway changes were examined sequentially. To evaluate postoperative changes within groups, the Wilcoxon signed-rank test was employed, while the Mann-Whitney U test was used for between-group comparisons. Immediate postoperative changes in the airway were correlated to surgical movements using the Spearman rank test.
UNASSIGNED: Significant changes in the MPA were observed in both the titanium and bioabsorbable groups at 3-6 months post-surgery, with significance persisting in the bioabsorbable group at 1 year postoperatively (2.29°±2.28°; P<0.05). The bioabsorbable group also exhibited significant EOP changes (-1.21±1.54 mm; P<0.05) at 3-6 months, which gradually returned to non-significant levels by 1 year postoperatively.
UNASSIGNED: Osteofixation using bioabsorbable plates and screws is comparable to that achieved with titanium in long-term skeletal stability and maintaining pharyngeal airway dimensions. However, a tendency for relapse exists, especially regarding the MPA.

UNASSIGNED: Metastasis to parapharyngeal space in papillary carcinoma of the thyroid is rare and often missed in routine clinical and radiological investigations. Although contrast CT /MRI can be done to locate the parapharyngeal lesion, the diagnosis of metastasis mostly deepened upon aspiration cytology, which is a challenge in difficult anatomical locations. Here, we have emphasized the management dilemma of parapharyngeal metastasis in papillary carcinoma of the thyroid.
UNASSIGNED: A 30-year-old female presented with multiple right-side neck swelling for two months. Ultrasonography of right thyroid showed TIRAD V and left thyroid showed TIRAD II. Aspiration cytology of the right thyroid showed Bethesda III and aspiration cytology revealed thyroid follicles. Due to the diagnostic ambiguity, contrast-enhanced CT scan was advised. It revealed a hypervascular lymph node in the parapharyngeal space besides multiple right cervical lymph nodes and later changed the treatment plan.
UNASSIGNED: - Metastasis to parapharyngeal space in Papillary carcinoma of the thyroid is rare and often missed on routine evaluation. Contrast-enhanced CT/MRI can be added as a primary investigation in challenging cases of suspicious malignancy of the thyroid.

A case of pleomorphic adenoma of deep lobe of parotid in parapharyngeal space presented as intra oral swelling. FNAC showed features of pleomorphic adenoma. Surgery done through transcervical route. HPE of excised mass confirmed pleomorphic adenoma.

UNASSIGNED: Medullary thyroid carcinoma constitutes 5% to 10% of all thyroid cancers. Metastatic adenopathies may pose challenges in intricate anatomical locations, such as the parapharyngeal space. A rare case of metastatic medullary thyroid carcinoma in the parapharyngeal space has been treated in our unit using combined trans-cervical trans-oral robotic surgery. Our objective was to provide a detailed description of the surgery performed on this patient.
UNASSIGNED: We reported a singular case report worth of interest.
UNASSIGNED: A 42-year-old woman was addressed in our unit for the management of a medullary thyroid carcinoma adenopathy located in the right parapharyngeal space. A parapharyngeal 40.0 mm × 25.0 mm × 12.0 mm adenopathy was removed using a combined trans-cervical and trans-oral robotic approach without sacrifice or injury of vascular or nervous structure. Neither the tracheostomy nor the feeding tube was implemented. Feeding was resumed on postoperative day 1 and hospitalization spanned 7 days.
UNASSIGNED: An innovative combined trans-cervical and trans-oral robotic surgery approach was conducted to address a metastatic medullary thyroid carcinoma in the parapharyngeal space. This surgical technique allowed us to circumvent the need for a trans-mandibular approach, tracheostomy, and feeding tube and enabling successful tumor removal without fragmentation. Postoperative care was significantly eased. The sole complication observed was dysphonia, likely resulting from intra-operative stretching of the vagus nerve during the dissection of the carotid artery.

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.
摘要: 咽旁间隙是头颈部复杂的筋膜间隙，其内包含血管、神经等重要解剖结构。发生于咽旁间隙的肿瘤少见，以良性病变为主，手术是主要治疗方法。由于解剖结构复杂，咽旁间隙肿瘤手术具有挑战性。传统咽旁间隙肿瘤手术以开放入路为主，手术创伤大、术后并发症发生率高。随着解剖研究的深入和手术技术的发展，近年咽旁间隙解剖和手术入路研究取得一定进展，本文将围绕这一主题进行综述。.

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.
目的：描述外侧入路和内镜腹侧入路咽旁段颈内动脉的解剖路图，提出亚分段方案，系统全面地理解该段动脉解剖以及其与周围结构的毗邻关系。 方法：对5例（共10侧）新鲜尸头标本分别进行外侧入路和内镜腹侧入路解剖对照，评估咽旁段颈内动脉解剖及毗邻关系。 结果：自颈总动脉分叉到颈内动脉管后垂直部，顺血流方向，咽旁段颈内动脉穿行通过4种截然不同的解剖组织，据此，该段颈内动脉可以划分为神经段、肌肉段、筋膜段、骨段4个亚分段。每个亚分段的边界和毗邻的重要解剖结构被详细描述。 结论：咽旁段颈内动脉的解剖路图描述和亚分段方案，为降低颈内动脉损伤风险，模块化开展经外侧和内镜腹侧入路咽旁间隙等颅底手术，提供了应用解剖学依据。.