Endoscopic trans-eustachian tube approach: identifying the precise landmarks, a novel radiological and anatomical evaluation.

PURPOSE: The endoscopic trans-eustachian approach (ETETA) is a less invasive approach to the infratemporal fossa (ITF), providing superior exposure compared to traditional transcranial approaches. The anatomy of the pharyngotympanic (eustachian) tube and adjacent neurovascular structures is complex and requires in-depth knowledge to safely perform this approach. We present a cadaveric and radiological assessment of critical anatomic considerations for ETETA. METHODS: Six adult cadaveric heads were dissected alongside examination of 50 paranasal sinus CT scans. Key anatomic relationships of the pharyngotympanic tube and adjacent structures were qualitatively and quantitatively evaluated. Descriptive statistics were performed for quantitative data. RESULTS: Anatomical and radiological measurements showed lateralization of the pharyngotympanic tube allows access to the ITF. The pharyngotympanic tube has bony and cartilaginous parts with the junction formed by the sphenoid spine and foramen spinosum. The bony part and tendon of the tensor tympani muscle were located at the posterior genu of the internal carotid artery. The anterior and inferior wall of the carotid canal was located between the horizontal segment of the internal carotid artery and petrous segment of the cartilaginous pharyngotympanic tube. CONCLUSION: The combination of preoperative radiographic assessment and anatomical correlation demonstrates a safe and effective approach to ETETA, which allowed satisfactory visualization of ITF. The morphological evaluation showed that the lateralization of the pharyngotympanic tube and related structures allowed a surgical corridor to reach the ITF. Endoscopic surgery through the pharyngotympanic tube is challenging, and in-depth understanding of the key anatomic relationships is critical for performing this approach.

Post-traumatic transocular retained foreign body in the infratemporal fossa: a near miss.

The infratemporal fossa is an uncommon site for lodgement of foreign bodies. Fast-moving projectiles and displaced teeth may get impacted and have been described in the literature. However, foreign body lodgement in the retromaxillary space after transorbital passage is rare. The trajectory of the foreign bodies in such cases is difficult to predict and may not be suspected in the absence of overt clinical features. The authors present a case of a wooden splinter lodged within the infratemporal fossa after the patient sustained a lid injury with an orbital floor fracture. Imaging was equivocal; hence, endoscopic surgical exploration was undertaken, revealing the foreign body. A high index of clinical suspicion and rapid intervention is needed since unsuspected foreign bodies may cause further visual, infective or neurovascular complications. Approaches should be tailored on a case-by-case basis.

[The efficacy and safety analysis of endoscopic resection for infratemporal fossa benign mass].

Objective: To investigate the efficacy and safety of endoscopic resection of infratemporal fossa mass and to determine the indications for surgery. Methods: A retrospective case series study was conducted, including a total of 29 patients who underwent endoscopic surgery to treat infratemporal fossa mass in the Department of Rhinology of Beijing Tongren Hospital, Capital Medical University, from April 2008 to December 2021. Ten males and 19 females were included in the study, with age of (46.5±13.7) years. Pre-and post-operative sinus CT, sinus or nasopharyngeal enhanced MRI were evaluated, respectively. The main outcome measurements were the total resection of mass and the incidence of surgery-related complications. Results: Among the 29 cases of infratemporal fossa mass, 22 were schwannomas, 3 were cysts, 2 were neurofibromas, 1 was pleomorphic adenoma and 1 was basal cell adenoma. Preoperative imaging showed well-defined lesion boundaries, and postoperative pathology confirmed the benign nature of all cases. The endoscopic transnasal approach was used in 28 patients, while the combination of the transnasal approach and the transoral approach was used in 1 patient. Complete tumor removal was achieved in all cases with a 100% resection rate. The average follow-up time was 38 months (7-168 months), and no tumor recurrence was observed. Conclusions: The Endoscopic transnasal approach is a safe and effective surgical approach for the treatment of benign tumors or masses in the infratemporal fossa.

Anatomic Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Infratemporal Fossa Approach to the Jugular Foramen.

BACKGROUND AND OBJECTIVES: The infratemporal fossa (ITF) is a complex region bounded by the temporal bone, maxilla, sphenoid, pterygoid plates, and mandibular ramus. Containing a high density of neurovascular and musculoskeletal structures, the ITF can house a number of pathologies, and access is challenging. The ITF approach and its variations can be challenging due to complex anatomy and unfamiliarity by many surgeons. The objective of this study was to present a step-by-step 3-dimensional anatomic dissection for the classic Fisch Type A and modified ITF approach from the surgeon's perspective. METHODS: Six sides of 3 formalin-fixed latex-injected specimens were dissected under microscopic magnification (JRD and AMN). Standard Fisch Type A and modified ITF approaches were performed on contralateral sides of each specimen. Representative high-quality 3-dimensional photography was performed for each key step. RESULTS: The ITF approach affords excellent access to the posterior ITF and jugular foramen. Modifications to this approach include preservation of the ear canal and limiting facial nerve transposition, thus limiting morbidity while generally still providing sufficient access to key anatomic structures. CONCLUSION: The ITF approach provides access to the lateral skull base for jugular foramen paraganglioma and other lesions. Modifications of the classic Fisch Type A technique can be used to access pathologies in this region without sacrificing conductive hearing or facial nerve function. Three dimensional operatively oriented neuroanatomy dissections provide surgeons with a valuable resource for learning this complex surgical approach.

Dermoid cyst of the infratemporal fossa: a case report of surgical resection by infratemporal fossa type B approach.

OBJECTIVE: This is a case report of a dermoid cyst located in the infratemporal fossa and its surgical removal using infratemporal fossa type B approach. CASE REPORT: A 15-year-old male was referred from a local clinic after an incidental finding of a mass lesion in the skull base area on computed tomography (CT). Pre-operative magnetic resonance imaging showed a large cystic mass lesion, expanding to the foramen ovale with fat component in the right infratemporal fossa region. The lesion was completely excised using an infratemporal fossa type B approach. CONCLUSION: An extremely rare case of dermoid cysts of the infratemporal fossa was managed with infratemporal fossa type B approach without severe complication.

Predictors of postoperative performance status after surgical management of infratemporal fossa malignancies.

Infratemporal fossa (ITF) tumors are difficult to access surgically due to anatomical constraints. Moreover, aggressive ITF carcinomas and sarcomas necessitate aggressive treatment strategies that, along with tumor-related symptoms, contribute to decreases in patient performance status. To assess factors that predict postoperative performance in patients undergoing surgery for ITF tumors. We reviewed medical records for all patients surgically treated for an ITF malignancy between January 1, 1999, and December 31, 2017, at our institution. We collected patient demographics, preoperative performance, tumor stage, tumor characteristics, treatment modalities, pathological data, and postoperative performance data. The 5-year survival rate was 62.2%. Higher preoperative Karnofsky Performance Status (KPS) score (n = 64; p < 0.001), short length of stay (p = 0.002), prior surgery at site (n = 61; p = 0.0164), and diagnosis of sarcoma (n = 62; p = 0.0398) were predictors of higher postoperative KPS scores. Percutaneous endoscopic gastrostomy (PEG) (n = 9; p = 0.0327), and tracheostomy tube placement (n = 20; p = 0.0436) were predictors of lower postoperative KPS scores, whereas age at presentation (p = 0.72), intracranial tumor spread (p = 0.8197), and perineural invasion (n = 40; p = 0.2195) were not. Male patients and patients with carcinomas showed the greatest decreases in KPS scores between pretreatment and posttreatment. Higher preoperative KPS score and short length of stay were the best predictors of higher postoperative KPS scores. This work provides treatment teams and patients with better information on outcomes for shared decision-making.

Using transfixion irrigation with negative pressure drainage (TINPD) minimally invasive to manage infratemporal fossa (ITF) abscess.

RATIONALE: The treatment of abscess in the infratemporal space is still controversial and bedside and operative intraoral drainage is often used to resolve the abscess. However, it can be difficult to control the infection quickly.[1] In this report, the authors present a new technique of using transfixion irrigation with negative pressure drainage for minimally invasive management of infratemporal fossa abscess. PATIENT CONCERNS: A 45-year-old man with type 2 diabetes complained of painful swelling and trismus in the right lower facial region for 10 days. The patient was weak, with mild anxiety, and gradually aggravated. DIAGNOSES: The patient was misdiagnosed and received dental pulp treatment for the right mandibular first molar and was given oral cefradine capsules (500 mg 3 times per day). Computed tomography scan and puncture revealed an abscess in the infratemporal fossa. INTERVENTION: The authors used transfixion irrigation with negative pressure drainage from different directions to reach the abscess cavity. Saline solution was infused through 1 tube and allowed to flow out through the other tube to flush out the pus and debris from the abscess. OUTCOME: On day 9, the drainage tube was removed and the patient was discharged. One week later, the patient was followed up in the outpatient clinic and the impacted mandibular third molar was removed. This technique is less invasive and leads to faster recovery times and fewer complications. LESSONS SUBSECTIONS: The report highlights the importance of proper preoperative evaluation, using a thoracic drainage tube as soon as possible, and continuous flushing. A double-lumen drainage tube with a suitable diameter and combined flushing should be designed for future reference. Moreover, the use of drugs can effectively eliminate emboli formation, allowing for faster and more minimally invasive control and removal of the infection.[2].

Enbloc resection of primary oral cancer involving infratemporal fossa: A systematic "out to in and top to bottom" surgical approach and outcomes.

AIM AND INTRODUCTION: The oral cavity Squamous Cell Carcinoma (OCSCC) involving infratemporal fossa (ITF) is considered as cT4b stage per AJCC 8th classification. The treatment of these group of patients is challenging due to the difficulty in achieving negative resection margin status. In this study we have highlighted our surgical technique with oncological outcome of enbloc resection of primary oral cancer involving ITF. METHODOLOGY: - This was a single center retrospective study which included only patients with OCSCC extending into ITF. Our surgical technique of systematic "out to in and top to bottom" approach was detailed. The perioperative outcomes, histopathological details, survival outcomes were measured. RESULTS: - Over the period of 1 year a total of 340 patients with OCSCC reported to our outpatient department, out of which 120 patients belonged to cT4 category and 32 patients were cT4b stage with involvement of ITF. Amongst 32 patients, 2 patients had distant metastasis and were excluded from the study. The 5 patients received neoadjuvant chemotherapy followed by surgery and rest all patients were taken up for upfront curative surgery. There were no significant intraoperative and postoperative complications. None of the margins were found to be involved or close in the final histopathology report. The median DFS and OS were 31 months and 27 months respectively at a median follow up of 29 months. CONCLUSION: - Our systematic approach of enbloc resection of primary oral cancer involving ITF is safe and easily reproducible with high rate of negative resection margin status.

Morphometric analysis of the infratemporal fossa using three-dimensional (3D) digital models.

PURPOSE: The infratemporal fossa contains important neurovascular components and is directly related to other anatomical regions and structures. The morphometric distances between the bones forming its borders have not been thoroughly investigated. The aim of this study was to determine the morphometry of the infratemporal fossa. METHODS: 3D models of the skull of 83 individuals were reconstructed from DICOM datasets, from which length, depth and width measurements were determined and compared between genders and the right and left sides. RESULTS: All measurements obtained were significantly different between males and females. There were also significant differences between the left and right sides for depth and width measurements. CONCLUSION: This is the first study to determine and investigate measurements of the infratemporal fossa; as such it provides a comprehensive view of the morphology of the fossa. It provides valuable information for surgical interventions and differential diagnoses of pathologies in this region, as well as enhancing its understanding in medical education.

Endoscopic Multiport Approach for Exenteration of the Infratemporal Fossa.

OBJECTIVE: To demonstrate anatomic relationships pertinent to the endoscopic multiport approach to the infratemporal fossa (ITF). Discuss advantages and limitations of each individual approach. STUDY DESIGN: Cadaveric study. METHODS: Endoscopic and endoscopic-assisted endonasal transpterygoid, sublabial transmaxillary, endoscopic transorbital, and endoscopic transoral approaches to accessing the ITF were completed in five silicone-injected fresh cadaveric specimens (10 sides) with the assistance of 0, 30, and 450 rods-lens endoscopes. Image guidance was used to confirm and document the anatomical relationships encountered in each approach. RESULTS: The endonasal endoscopic transpterygoid approach provides better visualization and more direct exposure to median structures. Endoscopic-assisted sublabial transmaxillary approach enhances the field of exposure, angle of attack, and ease of instrumentation to the lateral part of the ITF. Endoscopic-assisted transorbital approach via the inferior orbital fissure provided cephalic and anterior access. Endoscopic-assisted transoral approach complements the access to lesions extending inferior to the hard palate or far lateral to the mandibular condyle. CONCLUSIONS: A combination of minimal access infratemporal approaches can provide adequate exposure of the entire ITF while avoiding some of the morbidity associated with open approaches. LEVEL OF EVIDENCE: NA Laryngoscope, 133:1367-1374, 2023.

Combined endoscopic endonasal & transoral approach to transpatial lesion involving the infratemporal fossa and masticator space: A case study and literature review.

Transpatial skull base lesions involving the infratemporal fossa (ITF) are challenging due to the complex neurovascular structures of the region. Open approaches have traditionally been utilized to access these spaces. We present a 55-year-old woman presented with a mesenchymal mass involving the left ITF and masticator space. A combined endoscopic endonasal transpterygoid approach was performed followed by an endoscopic transoral-transmandibular corridor to access and resect the tumor. The post-operative course was unremarkable with no recurrence during her follow-up. Combined endoscopic approaches for transpatial tumor resection offered sufficient exposure to access safely each space.

Management of a recurrent right juvenile nasopharyngeal angiofibroma using direct tumorous puncture embolisation and a subtemporal-preauricular infratemporal fossa surgical approach.

A juvenile nasopharyngeal angiofibroma (JNA) is a benign vascular tumour that arises from the pterygopalatine fossa. It is seen near exclusively in young males though female cases have been reported. Symptoms are due to their high vascularity and mass effect. Commonly reported symptoms include: nasal obstruction, epistaxis and nasal discharge. The mainstay of treatment is surgical resection either via an endonasal endoscopic approach or open surgical resection. Preoperative embolisation has been shown to decrease intraoperative bleeding. Embolisation may be undertaken via a transarterial (TA) approach or, more recently, via direct tumorous puncture (DTP). Options for recurrent or residual disease may include revision surgery, radiotherapy or close clinical surveillance. The following case presentation describes the management of a recurrent JNA in an adult male using preoperative embolisation via a combination of TA and DTP embolisation and an open surgical resection via a subtemporal-preauricular infratemporal fossa approach.

Access to the infratemporal fossa: A modified transzygomatic approach with preservation of masseter attachment and a long-term follow-up period.

This study aimed to introduce and evaluate the feasibility of a modified transzygomatic approach with preservation of masseter attachment for the management of infratemporal fossa tumors. This retrospective study included 20 patients treated at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, between June 2007 and August 2017. Pre- and postoperative radiological findings (magnetic resonance imaging and computed tomography) were obtained from all patients. During an average 67 months of follow-up, no clinical or radiographic signs were found of recurrence or absorption of zygomatic arch defects. The mean visual analog scale score changed from 5.5 preoperatively to 0.6 postoperatively (P<0.001), while the mean maximum inter-incisal opening improved from 21.5 mm preoperatively to 38.7 mm postoperatively (P<0.001). Thus, managing infratemporal lesions using the modified transzygomatic approach may provide functional and esthetically established outcomes.

Granulomatous Mucormycosis of the Temporal Bone extending Into Temporomandibular Joint and Infratemporal Fossa: A Case Report.

Mucormycosis of temporal bone is extremely rare. They are usually associated with host immunodeficiency, are difficult to diagnose, and many cases are fatal. We performed a literature review and found only 10 reported cases of temporal bone mucormycosis. We present a case of temporal bone mucormycosis involving the temporomandibular joint and infratemporal fossa in a 53-year-old woman with diabetes mellitus who presented with unbearable otalgia. Computed tomography and magnetic resonance imaging demonstrate inhomogeneous density mass in the parapharyngeal and retropharyngeal space accompanied with lytic bone destruction on the temporomandibular joint. After undergoing a biopsy of the left infratemporal fossa, the patient's pathology exhibited fungal hyphae consistent with mucormycosis. To our knowledge, this is the first report of temporal bone mucormycosis with extensive involvement of temporomandibular joint and its adjacent structures, which exhibited no otologic or rhinologic signs. A definitive diagnosis is made by biopsy.

[Metastatic Tumor of the Uterine Cervical Cancer Occurred in the Infratemporal Fossa].

A 46-year-old woman presented with discomfort in her right lateral gaze, right-sided headache, and facial numbness 17 days after concurrent chemoradiotherapy(CCRT)for a Stage ⅢB cervical cancer. The initial imaging investigations, maxillofacial and otolaryngology reviews did not reveal a diagnosis. After 54 days of CCRT, her symptoms deteriorated. Magnetic resonance imaging(MRI)showed a tumor in the right infratemporal fossa and its biopsy confirmed a metastatic cervical cancer. In view of the rapid deterioration and the potential visual loss, palliative intensity-modulated radiotherapy(IMRT) was given. Although the symptoms improved temporarily, multiple metastases were subsequently found. Despite chemotherapy, the patient died 11 months after developing the symptoms of infratemporal fossa metastasis.

[Clinical practice of infratemporal fossa benign tumor endoscopic transnasal/oral surgery in 36 patients].

Objective:According to the characteristics of endoscopic transnasal and transoral surgery for infratemporal fossa tumors, we divided and named subzones of the infratemporal fossa, to explore the approaches of endoscopic transnasal and transoral surgery for infratemporal fossa tumors, and to analyze their advantages and disadvantages. Methods:We retrospectively analyzed the clinical data of 36 patients with benign tumors of infratemporal fossa successfully resected through nose or mouth under endoscope, summarized and analyzed the localization characteristics of these tumors in infratemporal fossa, and made a subzone naming rule of infratemporal fossa. We also summarized the selection principles, advantages and disadvantages of endoscopic transnasal and transoral surgical approaches. Results:The infratemporal fossa area is divided into ABC area. Area A is the fat pad area posterolateral of maxillary sinus. Area B is further divided into B1 （above the plane of maxillary sinus floor, anterior styloid process）, B2 （below the plane of maxillary sinus floor, anterior styloid process）, and B3 （posterior styloid process to anterior vertebra）; Area C is retropharyngeal and eustachian tube area. The location of the tumor in the infratemporal fossa determines the choice of transnasal and transoral approaches. All tumors were completely removed, and no tumor recurred during the follow-up. A few patients had temporary local sensory function decline, and recovered during the follow-up. Conclusion:The infratemporal fossa region naming rule according to the characteristics of endoscopic transoral and transnasal surgery approach is simple and practical, which can effectively guide the operation of the infratemporal fossa region and has clinical application value.

Combined endoscopic endonasal transpterygoid and sublabial transmaxillary approaches for a large infratemporal fossa trigeminal schwannoma.

BACKGROUND: Trigeminal schwannomas (TSs) with solitary extracranial location are rare, and surgical excision is challenging. In recent years, the endoscopic endonasal transmaxillary transpterygoid approach (EETPA) has been advocated as an effective strategy for TSs in the infratemporal fossa (ITF). METHOD: We describe the steps of the EETPA combined with the sublabial transmaxillary approach for the surgical excision of a giant mandibular schwannoma of the ITF. Indications, advantages, and approach-specific complications are also discussed. The main surgical steps are shown in an operative video. CONCLUSION: A combined EETPA and sublabial transmaxillary approach represents a safe and effective option for the surgical excision of extracranial TSs.

Transnasal Endoscopy and Combined Approach to Infratemporal Fossa Abscess and Parapharyngeal Abscess.

The infratemporal fossa is a very important anatomical space that is relatively closed with an irregular shape and is adjacent to the parapharyngeal space. Infratemporal fossa abscess is rare clinically. It can occur as a complication of maxillary sinusitis, maxillary sinus fracture, or odontogenic infection. If not handled in time, it may endanger the lives of patients. This paper reports the diagnosis and treatment of infratemporal fossa abscess in 2 diabetic patients. Computed tomography and magnetic resonance imaging are the best methods to diagnose suspected cases of this disease. The key treatment is to combine sensitive antibiotic treatment with endoscopic abscess drainage. Different approaches can be selected according to the range of lesions. If necessary, a combined approach to drain the pus is needed. Early diagnosis, timely initiation of antibiotics, and surgical intervention are essential for curing this disease.