Preauricular transzygomatic anterior infratemporal fossa approach for tumors in or around infratemporal fossa lesions

Interdisciplinary Management of Skull Base Tumors

OBJECTIVE

Endoscopic endonasal skull base surgery has gained acceptance worldwide. Comparative analysis has demonstrated that endoscopic skull base surgery may have advantages for many pathologies of the anterior skull base, e. g., sinonasal malignant tumors; pathologies of the central skull base, e. g., pituitary adenomas, craniopharyngiomas; well-selected cases of planum sphenoidale and tuberculum sellae meningiomas; or for clival lesions, e. g., chordomas, chondrosarcomas, or selected meningiomas. Over the past three decades, interdisciplinary surgical teams, consisting of otolaryngologists and neurosurgeons, have provided detailed anatomical knowledge, suggested new approaches or modifications of established surgical techniques, and offered continued surgical education.

METHOD

A review of pertinent literature was conducted with an emphasis on interdisciplinary endoscopic surgery of skull base lesions.

RESULTS

Based on the authors̓ surgical experience in two different interdisciplinary endoscopic skull base centers, the authors classify approaches for endoscopic endonasal skull base surgery, describe indications, and key anatomic landmarks for common pathologies, and highlight surgical techniques to avoid complications.

CONCLUSION

Interdisciplinary endonasal endoscopic surgery combines surgical expertise, improves resection rates for many pathologies, and minimizes morbidity by reducing the incidence of surgical complications.

Anterior endoscopic sublabial transmaxillary access to middle cranial base lesions

BACKGROUND

Anterior endoscopic access to middle cranial base lesions becomes feasible in the presence of infratemporal fossa (ITF) involvement. Various approaches, including endoscopic endonasal, transoral sublabial, and transorbital methods, have been described for accessing the ITF through a transmaxillary corridor. Among these approaches, endonasal access is the most commonly preferred, while the transorbital approach is a novel technique gaining popularity. The transoral sublabial approach is considered suitable for selected lesions.

METHODS

Patients who underwent the anterior endoscopic transoral/sublabial transmaxillary approach to middle cranial base lesions at a single institute from 2016 to 2023 were included in this retrospective study. Malignant lesions were excluded from the study. The sublabial approach was exclusively performed in all cases, with the exception of one patient who required a combined approach.

RESULTS

The anterior endoscopic transoral sublabial transmaxillary approach to the infratemporal fossa, upper parapharyngeal space, and middle cranial fossa was performed on 14 patients. The underlying conditions for these patients were as follows: trigeminal schwannomas (n = 8), meningiomas (n = 2), juvenile nasopharyngeal angiofibroma, osteochondroma, arachnoid cyst and encephalocele (n = 1 each). Gross total resection was achieved in 11 cases. The most common complication was numbness in the territory of the maxillary and mandibular nerves (n = 4). Two patients needed endoscopic maxillary antrostomy for persistent suppuration. No wound problems or CSF rhinorrhea occurred. The average follow-up time was 26.6 months.

CONCLUSION

The endoscopic sublabial transmaxillary approach provides direct access to the infratemporal fossa and middle cranial base, enhancing the surgical range of maneuverability while sparing the sinonasal cavity. This procedure is safe, less invasive, and could be used as an efficient corridor for the resection of selected infratemporal fossa lesions with or without extension to the middle cranial base and parapharyngeal space.

Intramuscular lipoma of the temporalis muscle extending to the infratemporal fossa: surgical pitfalls and short literature review

Lipomas are benign tumours of mesenchymal origin, representing one of the most common tumours of the body. They are often observed between the fourth and the sixth decade of life and in 13% of the cases they occur in the head and neck region. In case of symptoms, surgical removal is the treatment of choice; when the formation involves the temporal region, the surgical approach is often challenging due to the presence of the neurovascular structures, such as the temporalis branch of the facial nerve and their potential extension to the nearby structures under the zygomatic arch to either the infratemporal fossa or the buccal region. Recurrence can occur frequently only if there is incomplete removal of lipoma. In this paper, the authors discuss surgical pitfalls of a very rare case of a large-sized symptomatic lipoma extended to the infratemporal and pterygomaxillary fossa, surgically removed via trans-zygomatic hemicoronal approach.

Interdisciplinary management of skull base surgery

Skull base surgery remains one of the challenging areas in the field of cranio-maxillofacial surgery, otolaryngology and neurosurgery. Subsequent reconstruction of bone and soft tissue are an essential component to restore function and appearance after ablative surgery. Establishment of interdisciplinary tumor boards with presentation of the individual patient cases have become standard. Multiplanar reconstruction using MRI or CT imaging techniques combined with virtual 3D planning allow precise planning of the procedures. Intraoperative navigation helps for complete resection of malignant findings with safety margins; surgical approaches provide a good overview of the surgical site. Reconstruction using local flaps have a low complication rate with equally reliable results in reconstruction of small tissue defects. Free flap surgery makes reconstruction of large tissue defects possible. Alloplastic materials are alternatively used for reconstruction of bone defects. Based on selected patients, treatment algorithms and standard surgical procedures in extracerebral skull base surgery will be illustrated. Current techniques and new approaches will be discussed with emphasize on hard and soft tissue reconstruction.

Extradural anterior temporal fossa approach to the paranasal sinuses, nasal cavities through the anterolateral and anteromedial triangles: Combined microscopic and endoscopic strategy

OBJECTIVE

To demonstrate the utility and limitations of the extradural endoscopic-assisted anterior temporal fossa approach to the pterygopalatine fossa (PPF), infratemporal fossa (ITF), paranasal sinuses (PS), parapharyngeal region (PPR), nasal cavities (NC), epipharynx (EP), and clivus.

METHODS

A frontotemporal orbitozygomatic craniotomy is performed. The dura is elevated from the cavernous sinus (CS). The anterior temporal fossa floor is drilled. Foramen rotundum and ovale are opened. The PPF is exposed and the lateral margin of inferior orbital fissure (IOF) is removed. The anterolateral triangle (ALT) is drilled and the vidian nerve (VN) is exposed. Drilling between the maxillary nerve (V2) and the VN provides access to the sphenoid sinus (SphS). The medial pterygoid plate is drilled exposing the EP. The maxillary sinus (MaxS) is opened anterior to the PPF. V2 is transposed laterally to enlarge the anteriomedial triangle (AMT). The orbital muscle of Muller is removed as well as the medial margin of the IOF, which opens the SphS. Anteriorly, the posterior ethmoid air cells are opened. Morphometric measurements evaluating the size of the ALT were done and the PS, NC, EP were explored with the endoscope.

RESULTS

The ALT and AMT triangle provides a wide exposure of the PPF, ITF, PPR. In addition, those triangles represent a deep entry point to explore the PS, NC, and EP.

CONCLUSION

The ALT and AMT are useful corridors to access to the SphS, MaxS, PS, NC, and EP via a transcranial approach. The use of the endoscope through this corridor widely extend the extradural anterior temporal fossa approach which may be considered as a valuable alternative to the extended endoscopic endonasal approach for selected skull base lesions extending both intracranial and into the PS, NC and EP.

Rerouting the Dissection of the Infratemporal and Submandibular Regions

Introduction

Teaching and learning in anatomy are necessarily dependent on cadaveric dissection. Skillful dissection is the tool which helps in proper visualization of structures in a cadaver. Proper understanding about the course of lingual nerve, hypoglossal nerve, nerve to mylohyoid, and relations between structures present in infratemporal and submandibular regions is important for medical students. The aim of this study is to describe a modified technique of dissection and evaluate medical students' and teachers’ response to this approach.

Methods

The comparative observational study was conducted bilaterally on six adult cadavers. We compared the method of dissection given in standard textbooks with the modified method introduced. The validity and reliability of the newer method of dissection for teaching purpose was assessed by first-year undergraduate medical students using a questionnaire-based tool and feedback from postgraduate students and senior residents.

Results

The modified method was described as less time consuming, easy to perform, and allowed extensive exploration of the structures in the infratemporal and submandibular regions.

Conclusions

Proper understanding of the course and relations between structures present in infratemporal and submandibular regions is important for medical students.The modified approach to infratemporal and submandibular regions will facilitate better understanding of the human anatomy.

The orbitopterygoid corridor as a deep keyhole for endoscopic access to the paranasal sinuses and clivus

OBJECTIVE

The anteromedial triangle (AMT) is the triangle formed by the ophthalmic (V1) and maxillary (V2) nerves. Opening of this bony space offers a limited access to the sphenoid sinus (SphS). This study aims to demonstrate the utility of the orbitopterygopalatine corridor (OPC), obtained by enlarging the AMT and transposing the contents of the pterygopalatine fossa (PPF) and V2, as an entrance to the SphS, maxillary sinus (MaxS), and nasal cavity.

METHODS

Five formalin-injected cadaveric specimens were used for this study (10 approaches). A classic pterional approach was performed. An OPC was created through the inferior orbital fissure, between the orbit and the PPF, by transposing the PPF inferiorly. The extent of the OPC was measured using neuronavigation and manual measurements. Two illustrative cases using the OPC to access skull base tumors are presented in the body of the article.

RESULTS

Via the OPC, the SphS, MaxS, ethmoid sinus (EthS), and nasal cavity could be accessed. The use of endoscopic assistance through the OPC achieved better visualization of the EthS, SphS, MaxS, clivus, and nasal cavity. A significant gain in the area of exposure could be achieved using the OPC compared to the AMT (22.4 mm2 vs 504.1 mm2).

CONCLUSIONS

Opening of the AMT and transposition of V2 and the contents of the PPF creates the OPC, a potentially useful deep keyhole to access the paranasal sinuses and clival region through a middle fossa approach. It is a valuable alternative approach to reach deep-seated skull base lesions infiltrating the cavernous sinus and middle cranial fossa and extending into the paranasal sinus.

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.

Contemporary management of primary parapharyngeal space tumors

The parapharyngeal space is a complex anatomical area. Primary parapharyngeal tumors are rare tumors and 80% of them are benign. A variety of tumor types can develop in this location; most common are salivary gland neoplasm and neurogenic tumors. The management of these tumors has improved greatly owing to the developments in imaging techniques, surgery, and radiotherapy. Most tumors can be removed with a low rate of complications and recurrence. The transcervical approach is the most frequently used. In some cases, minimally invasive approaches may be used alone or in combination with a limited transcervical route, allowing large tumors to be removed by reducing morbidity of expanded approaches. An adequate knowledge of the anatomy and a careful surgical plan is essential to tailor management according to the patient and the tumor. The purpose of the present review was to update current aspects of knowledge related to this more challenging area of tumor occurrence.

The maxillary artery as a recipient vessel option for complex midface and anterior skull base microsurgical repair: A cadaveric study

INTRODUCTION

Variations in the operative situation for complex head and neck defect reconstructions resulting from mechanisms such as trauma, oncologic resection, and prior radiation exposure can result in situations of a vessel-depleted neck. This requires an awareness of alternate, innovative options for use in reconstructive repairs. The purpose of this study was to provide characterization of the third segment of the maxillary artery necessary to consider its use as a recipient vessel in free flap repair of complex midface defects.

MATERIALS AND METHODS

Seventeen cadaver hemifaces were used for anatomic demonstration of the maxillary artery third segment by a transmaxillary approach to obtain descriptive measures for statistical analysis.

RESULTS

The average artery intraluminal cross-section diameter was obtained for the sphenopalatine (1.39 ± 0.12 mm) descending palatine (0.94 ± 0.10 mm), and terminal maxillary (1.68 ± 0.17 mm) arterial vessels. The mean transmaxillary depth with was (43 ± 1.2 mm). Mean mobilizable lengths for sphenopalatine, descending palatine, and terminal maxillary arteries were (30 ± 2 mm), (29 ± 2 mm), and (20 ± 2 mm), accordingly. Vessel patterns were characterized using Morton and Kahn classification for sphenopalatine-descending palatine bifurcation as well as the Kwak classification for maxillary artery third segment morphology.

CONCLUSIONS

In situations where primary recipient vessel sites are unavailable, the maxillary artery represents an innovative option to be considered with suitable recipient artery characteristics.

Combined Transzygomatic and Pterional Approach for Resection of a Dermoid Cyst of the Foreman Ovale

Dermoid cysts are rare, benign intracranial lesions commonly located in the posterior fossa. We describe a uniquely located dermoid cyst in the foreman ovale resected via a combined pterional and transzygomatic approach.

Middle infratemporal fossa less invasive approach for radical resection of parapharyngeal tumors: surgical microanatomy and clinical application

Surgery of the infratemporal fossa (ITF) and parapharyngeal area presents a formidable challenge to the surgeon due to its anatomical complexity and limited access. Conventional surgical approaches to these regions were often too invasive and necessitate sacrifice of normal function and anatomy. To describe a less invasive transcranial extradural approach to ITF parapharyngeal lesions and to determine its advantages, 17 patients with ITF parapharyngeal neoplasms who underwent tumor resection via this approach were enrolled in the study. All lesions located in the ITF precarotid parapharyngeal space were resected through a small operative corridor between the trigeminal nerve third branch (V3) and the temporomandibular joint (TMJ). Surgical outcomes and postoperative complications were evaluated. Pathological diagnosis included schwannoma in eight cases, paraganglioma in two cases, gangliocytoma in two cases, carcinosarcoma in one case, giant cell tumor in one case, pleomorphic adenoma in one case, chondroblastoma in one case, and juvenile angiofibroma in one case. Gross total resection was achieved in 12 cases, near-total and subtotal resection were in 3 and 2 cases, respectively. The most common postoperative complication was dysphagia. Surgical exposure can be customized from minimal (drilling of retrotrigeminal area) to maximal (full skeletonization of V3, removal of all structures lying lateral to the petrous segment of internal carotid artery) according to tumor size and location. Since the space between the V3 and TMJ is the main corridor of this approach, the key maneuver is the anterior translocation of V3 to obtain an acceptable surgical field.

Japanese neurosurgeons and microsurgical anatomy: a historical review

Research in microneurosurgical anatomy has contributed to great advances in neurosurgery in the last 40 years. Many Japanese neurosurgeons have traveled abroad to study microsurgical anatomy and played major roles in advancing and spreading the knowledge of anatomy, overcoming their disadvantage that the cadaver study has been strictly limited inside Japan. In Japan, they initiated an educational system for surgical anatomy that has contributed to the development and standardization of Japanese neurosurgery. For example, the Japanese Society for Microsurgical Anatomy started an annual educational meeting in the middle of 1980s and published its proceedings in Japanese every year for approximately 20 years. These are some of the achievements that bring worldwide credit to Japanese neurosurgeons. Not only should Japanese neurosurgeons improve their educational system but they should also contribute to the international education in this field, particularly in Asia.

Microsurgical anatomy of subtotal temporal bone resection en bloc with the parotid gland and temporomandibular joint

BACKGROUND

Subtotal temporal bone resection (STBR) has been used for half a century to remove temporal bone malignancies. However, there are few reports on the detailed anatomy involved in the resection.

OBJECTIVE

To describe the microsurgical anatomy of STBR combined en bloc with the resection of the parotid gland and temporomandibular joint (TMJ).

METHODS

Cadaveric specimens were dissected in a stepwise manner using 3× to 40× magnification.

RESULTS

STBR can be combined with the total parotidectomy and the resection of the TMJ if the tumor extends into the parotid gland, TMJ, or facial nerve. In this study, we describe the step-by-step microsurgical anatomy of STBR en bloc with the parotid gland and TMJ. The surgical technique described combines 3 approaches: the high cervical, subtemporal-infratemporal fossa, and retromastoid-paracondylar approaches. Combining these 3 approaches aided in efficiently completing this modified approach.

CONCLUSION

STBR is a complicated and technically challenging procedure. This study highlights the importance of understanding the surgical anatomy of STBR and will serve as a catalyst for improvement of the surgical technique for temporal bone resection.