Variant Innervation of the Medial Pterygoid Muscle from the Lingual Nerve.

During a routine dissection of the infratemporal fossa and lateral face, a branch of the left lingual nerve was observed entering the medial pterygoid muscle. Normally, the nerve to the medial pterygoid is a direct branch from the mandibular nerve, with no communications with the lingual nerve. There are many reports involving variations of the mandibular nerve; however, few reports describe lingual nerve variations involving the medial pterygoid muscle. Reconstructive surgeries for cosmesis and trauma, tumor excision, and impacted third molar removal may all damage the lingual nerve and might, as seen in the present case, affect the medial pterygoid muscle. Given the presumed rarity of this variation, we discuss the possible embryological origins as well as the surgical conflicts that may arise with this type of variation.

Endoscopic Trans-Lateral Molar Approach to Infratemporal Fossa Lesions.

BACKGROUND: To study the endoscopic trans-lateral molar (ETLM) approach to infratemporal fossa (ITF) lesions and analyze the advantages and disadvantages of this method. METHODS: Four cases of ITF lesions were analyzed retrospectively. The clinical features, diagnosis and treatments, the operative process, and clinical applications of this surgical approach were discussed. RESULTS: Postoperative pathologies were 2 pleomorphic adenomas, 1 schwannoma, and 1 inflammatory lesion. All patients had self-resolving cheek swelling and pharyngalgia in the short term, but 2 patients had numbness in the long term. There was no infection or bleeding in the postoperative period, and no difficulty in chewing after disease recovery. There was no tumor recurrence during the follow-up period. CONCLUSION: The ETLM approach is convenient, minimally invasive, and allows complete excision of benign ITF lesions, posterior to the lateral pterygoid muscle and mainly below the level of the hard palate. It is a simple and direct access to the ITF, but it is a narrow access because of the limitations of bones and soft tissues. Appropriate patient selection is mandatory for successful surgery.

Surgical management of carcinomas of the infratemporal fossa and skull base: patterns of failure and predictors of long-term outcomes.

OBJECTIVE: Infratemporal fossa (ITF) tumors are unique in histological characteristics and difficult to treat. Predictors of patient outcomes in this context are not known. The objective of this study was to identify independent predictors of outcome and to characterize patterns of failure in patients with ITF carcinoma. METHODS: All patients who had been surgically treated for anterolateral skull base malignancy between 1999 and 2017 at the authors' institution were retrospectively reviewed. Patient demographics, preoperative performance status, tumor stage, tumor characteristics, treatment modalities, and pathological data were collected. Primary outcomes were disease-specific survival (DSS) and local progression-free survival (LPFS) rates. Overall survival (OS) and patterns of progression were secondary outcomes. RESULTS: Forty ITF malignancies with skull base involvement were classified as carcinoma. Negative margins were achieved in 23 patients (58%). Median DSS and LPFS were 32 and 12 months, respectively. Five-year DSS and OS rates were 55% and 36%, respectively. The 5-year LPFS rate was 69%. The 5-year overall PFS rate was 53%. Disease recurrence was noted in 28% of patients. Age, preoperative performance status, and margin status were statistically significant prognostic factors for DSS. Lower preoperative performance status and positive surgical margins increased the probability of local recurrence. CONCLUSIONS: The ability to achieve negative margins was significantly associated with improved tumor control rates and DSS. Cranial base surgical approaches must be considered in multimodal treatment regimens for anterolateral skull base carcinomas.

Extended Middle Cranial Fossa Approach for Lesions Invading Infratemporal Fossa: Anatomic Study and Clinical Application.

Skull base tumors arising from the middle cranial fossa and invading of the infratemporal fossa (ITF) and middle cranial fossa are challenging for neurosurgeons, because of complex anatomy and critical neurovascular structure involvement. The first pioneering ITF approaches resulted in invasive procedures and carried a high rate of surgical morbidity. However, the acquisition of deep anatomical knowledge, and the development operative skills and reconstruction techniques allowed surgeons to achieve total or near total resection of many ITF lesions with a low morbidity rate. In Video 1 we illustrate our technique for the anterior ITF approach for the surgical treatment of a middle cranial fossa meningioma invading the ITF. This surgical video describes the anterior ITF approach in 2 steps. First, a standard extradural middle fossa approach subtemporal approach is performed on a cadaveric specimen, illustrating the anterior extension to the cavernous sinus. Second, the anterior ITF approach is performed for the surgical treatment of a temporal lobe meningioma with extension to the anterior ITF. This technique provides a minimally invasive approach for treating middle fossa lesions with anterior ITF extension.

Infratemporal fossa surgical approaches to primary/recurrent malignancies of salivary origin: paradigm surgical shift, patient selection, and oncologic outcomes.

PURPOSE OF REVIEW: To review, the surgical approaches available on diagnosing a patient with salivary gland malignancy in the infratemporal fossa (ITF). To comment on patient evaluation and method of treatment selection. To identify and report on patient outcome data and make recommendations on future needs. RECENT FINDINGS: There is a need to define the anatomic boundaries contents of the ITF, masticator space, parapharyngeal space (PPS), pterygopalatine fossa, ventral skull base, and paramedian skull base, as evidence from publications. The pathological subtypes identified mainly include adenoid cystic and mucoepidermoid carcinomas. The source of these tumours originates from primary disease in the sinonasal tract and nasopharynx superiorly, and the PPS/deep lobe of parotid inferiorly. Current surgical options available, in suitable selected patient, available in tertiary head and neck cancer hospitals, which have available facilities and staffing is the endoscopic endonasal approach. This approach offers patients a 'complete margin-free surgical excision', minimal complications, shorter hospital stay, and no delay with commencement of any adjuvant treatment compared with the traditional 'open transcutaneous' approach. SUMMARY: The current evidence specifically to the surgical management of salivary gland malignancy involving the ITF is sparse, with great difficult identifying treated patients and their details among a heterogeneous group of patients with many lesions. There is a need for patient data that have specific pathologic conditions to be amalgamated from such centers and publish on outcome events.

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.

Giant Cell Tumour of Temporal Bone and Infratemporal Fossa: A Rare Case.

Giant cell tumours (GCT) of the bone are uncommon primary bone neoplasms that occur mainly in the epiphysis of long bones. GCT of the skull is rarely encountered, particularly of the temporal bone. We report a rare case of giant cell tumour of the squamous portion of the temporal bone extending to the infratemporal fossa in a 38-year old male. The patient presented with progressive trismus, and swelling and pain in the right temporal region. The patient underwent excision of the mass by maxillary swing approach. The treatment of choice for GCT is complete surgical excision. Based on the location and extent of the GCT in the infratemporal fossa, several surgical approaches have been tried for its excision.

Successful management of recurrent adenoid cystic carcinoma in the deep infratemporal fossa by maxillo-orbito-zygomatic approach.

OBJECTIVE: In the case of deep invasion of an infratemporal fossa (ITF) tumor, surgeons find it difficult to gain sufficient visualization and working space by conventional surgical approaches. To overcome these limitations, we have developed a novel surgical technique, maxillo-orbito-zygomatic (MOZ) approach, by combining partial lateral maxillectomy with the conventional orbito-zygomatic approach. METHODS: A 63-year-old male presented with the fifth recurrent adenoid-cystic carcinoma in the right deep ITF. Using a Weber-Ferguson-type incision and partial dismasking, we elevated the skin and scalp flap, while preserving the facial nerve and orbicularis oculi muscle intact in the flap. Then, we performed MOZ osteotomy using three cut lines, the zygomatic arch, the frontozygomatic suture, and from the inferior orbital fissure to the anterolateral wall of the maxilla. Following this, we temporarily elevated the bone flap by partially opening the lateral maxillary sinus. We obtained an excellent surgical view of the ITF, middle skull base, and pterygopalatine fossa with this technique, which facilitated the safe removal of the tumor. RESULTS: The postoperative course remained almost uneventful, and we obtained favorable cosmetic results. CONCLUSIONS: Our novel MOZ approach could be a robust approach to remove deep ITF tumors.

Minimally Invasive Exposure of the Maxillary Artery at the Anteromedial Infratemporal Fossa.

BACKGROUND: The maxillary artery (MA) has been described as a reliable donor for extracranial-intracranial high-flow bypass. Existing techniques to harvest MA require brain retraction and drilling of the middle fossa (with or without a zygomatic osteotomy), carrying the potential risks of venous bleeding, injury to the branches of the maxillary or mandibular nerves, muscular transection, or temporomandibular junction disorders. OBJECTIVE: To describe a novel technique to expose the MA without bony drilling and with minimal impact to surrounding structures. METHODS: A conventional curvilinear incision was performed in 10 cadaveric specimens, prior to elevating the scalp to expose the zygomatic root and lateral orbital rim. The sphenozygomatic suture was followed to the anterolateral edge of the inferior orbital fissure (IOF) to locate and harvest the pterygoid segment of the MA. Topographic anatomy was assessed using surrounding landmarks and 3D Cartesian coordinates to define the surgical area. The number of visible MA branches and their lengths were recorded. RESULTS: The MA was successfully exposed in all specimens. This approach allowed 6 branches of MA to be exposed. The average length of exposure was 23.3 ± 8.3 mm and the average surgical area was 2.8 ± 0.9 cm2. The IOF was 11.5 ± 4.2 mm from the MA. CONCLUSION: Our technique provides landmarks to identify the distal pterygoid segment of MA as a donor for extracranial-intracranial bypasses without the need for additional craniectomies. Clear anatomical landmarks, including the sphenozygomatic suture, anterolateral edge of IOF, infraorbital artery, and the pterygomaxillary fissure defined a trajectory to efficiently localize the MA with minimal risk to surrounding structures.