Endonasal endoscopic approach to the pterygopalatine and infratemporal fossae

Transorbital Endoscopic Approach to the Foramen Rotundum for Infraorbital Nerve Stripping

PURPOSE

To develop and evaluate a transorbital endoscopic approach to the foramen rotundum to excise the maxillary nerve and infraorbital nerve branch.

METHODS

Cadaveric dissection study of 10 cadaver heads (20 orbits). This technique is predicated upon 1) an inferior orbital fissure release to facilitate access to the orbital apex and 2) the removal of the posterior maxillary wall to enter the pterygopalatine fossa (PPF). Angulations along the infraorbital nerve were quantified as follows: the first angulation was measured between the orbitomaxillary segment within the orbital floor and the pterygopalatine segment suspended within the PPF, while the second angulation was taken between the pterygopalatine segment and maxillary nerve as it exited the foramen rotundum. With refinement of the technique, the minimum amount of posterior maxillary wall removal was quantified in the final 5 cadaver heads (10 orbits).

RESULTS

The mean distance from the inferior orbital rim to the foramen rotundum was 45.55 ± 3.24 mm. The first angulation of the infraorbital nerve was 133.10 ± 16.28 degrees, and the second angulation was 124.95 ± 18.01 degrees. The minimum posterior maxillary wall removal to reach the PPF was 11.10 ± 2.56 mm (vertical) and 11.10 ± 2.08 mm (horizontal).

CONCLUSIONS

The transorbital endoscopic approach to an en bloc resection of the infraorbital nerve branch up to its maxillary nerve origin provides a pathway to the PPF. This is relevant for nerve stripping in the context of perineural spread. Other applications include access to the superior portion of the PPF in selective biopsy cases or in concurrent orbital pathology.

Transorbital Endoscopic Approach to the Pterygopalatine Fossa: A Less Invasive Alternative to Traditional Access

PURPOSE

The purpose of this article and accompanying video is to demonstrate a transorbital endoscopic approach for accessing the pterygopalatine fossa (PPF). This technique does not require a skin incision, avoids dissection of critical neurovascular structures, and utilizes a comparatively small osteotomy. The 2 cases presented in this article highlight the utility of a transorbital endoscopic approach for accessing an anatomic region that has traditionally required more invasive techniques to reach.

METHODS

Description of surgical technique with 2 illustrative clinical cases and accompanying surgical video.

RESULTS

Surgical technique: A trans-conjunctival approach is taken to the inferior orbital rim, and a subperiosteal dissection is propagated posteriorly. The bone of the posterior orbital floor is then deroofed, and the superior portion of the posterior wall of the maxillary sinus is removed, allowing access to the PPF for an incisional biopsy.

CASE

A 76-year-old male with a history of left cheek squamous cell carcinoma presented with progressive V2 paresthesia and an abnormally enhancing lesion in the left PPF on MRI.

CASE

A 58-year-old male with no significant medical history presented with left facial numbness (V1-V3), ptosis, an abduction deficit, and decreased hearing. Contrast-enhanced MRI demonstrated an abnormally enhanced lesion in the left PPF extending to Meckel's cave.The transorbital approach described was used to successfully obtain a diagnostic biopsy in both cases.

CONCLUSIONS

These cases highlight the utility of a transorbital endoscopic approach to the PPF as a less morbid alternative to traditional access. Patient selection is key to identifying appropriate cases.

Combined Endoscopic Transmaxillary Approach for Resection of an Extracranial V3 Schwannoma: 2-Dimensional Operative Video

Tumours of the pterygopalatine (PPF) and infratemporal fossa (ITF) are rare tumours and are difficult to access. The lateral cervical approach is hampered by the mandibular angle and the vascular nervous elements.1 The classic endonasal endoscopic medial maxillectomy approach has been developed over the past 2 decades but does not allow good control of the most lateral and inferior part of the ITF.2 The surgical video presents a 68-year-old woman with trigeminal neuralgia. The radiologic workup showed a trigeminal V3 schwannoma (TS) into the PPF and ITF. This tumor grew during the follow-up despite fractionated radiosurgery. A 2-dimensional intraoperative video illustrates the gross total removal of the TS through a combined endoscopic endonasal and transgingival transmaxillary approach. The combination of these 2 approaches allows on the one hand, a better view of the lateral and inferior part of the maxillary sinus and ITF and on the other hand, a gain of handling in the operating field and security for our surgical procedure.3 The mini-Caldwell-Luc approach gives good aesthetic results without stomatological complication. Neuralgia disappeared after the surgery, and a gross total resection was achieved, and no recurrence was observed during the follow-up. This combined approach is a good alternative of medial extended maxillectomy, which presents a risk for the lacrimal duct risk and postoperative aesthetic deformity because of the removal of the medial and anterior wall of the maxillary sinus. The patient consented to the procedure and publication of her image.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal and Endoscopic-Assisted Transmaxillary Transpterygoid Approaches

Introduction  The endoscopic endonasal transpterygoid approach (EETPA) with or without the addition of the endoscopic-assisted sublabial anterior transmaxillary approach (ESTA) has become increasingly utilized for lesions posterior to the pterygopalatine fossa (PPF), including infratemporal fossa (ITF), lateral recess of the sphenoid sinus, Meckel's cave, petrous apex, and parapharyngeal space. The main goal of this study is to develop an educational resource to learn the steps of the EETPA for trainees. Methods  EETPA and ESTA were performed in 12 specimens by neurosurgery trainees, under supervision from the senior authors. One EETPA and one ESTA were performed on each specimen on opposite sides. Dissections were supplemented with representative cases. Results  After a wide unilateral sphenoidotomy, ethmoidectomy, and partial medial maxillectomy, the anteromedial bone limits of the PPF were identified and drilled out. The pterygoid progress was modularly removed. By enlarging the opening of the posterior and lateral walls of the maxillary sinus through EETPA and ESTA, respectively, the neurovascular and muscular compartments of the PPF and ITF were better identified. The EETPA opens direct corridors to the PPF, medial ITF, middle cranial fossa, cavernous sinus, Meckel's cave, petrous apex, and internal carotid artery. If a more lateral exposure of the ITF is needed, the ESTA is an appropriate addition. Conclusion  Despite the steep learning curve of the EETPA, granular knowledge of its surgical anatomy and basic surgical steps are vital for those advancing their learning in complex endoscopic approaches to the ventral skull base when expanding the approach laterally in the coronal plane.

Endoscopic endonasal transpterygoid nasopharyngectomy: Anatomical considerations and technical note

BACKGROUND

The study was designed to identify new landmarks in the parapharyngeal segment of the internal carotid artery (ICA) for nasopharyngectomy and describe a surgical procedure of endoscopic endonasal transpterygoid nasopharyngectomy (EETPN).

METHODS

Four cadaveric specimens were injected with colored silicone and subjected to CT scanning before dissection. The nasopharyngeal skull base was exposed using the endoscopic endonasal transpterygoid approach. The clinical data of four patients with nasopharyngeal malignances who underwent EETPN were reviewed.

RESULTS

The lateral edge of the longus capitis muscle medially; the foramen lacerum, petrous apex spine and the stump of the levator veli palatini muscle superior laterally; and the upper parapharyngeal ICA laterally constitute the ICA-longus capitis muscle-petrous apex spine triangle which was a novel landmark for the upper parapharyngeal segment of the ICA.

CONCLUSION

The ICA-longus capitis muscle-petrous apex spine triangle are important landmarks of the upper parapharyngeal segment of the ICA.

Endoscopic Endonasal Surgery to Resect a Solitary Trigeminal Neurofibroma Involving the Infratemporal Fossa: A Case Report

Trigeminal neurofibromas are rarely reported, and even rarer when involving the infratemporal fossa. We describe the case of a 58-year-old man incidentally found through magnetic resonance imaging to have a tumor situated mainly in the infratemporal fossa. The tumor derived from the third branch of the trigeminal nerve and was totally removed by endoscopic endonasal surgery. Final pathology confirmed a diagnosis of neurofibroma. The patient had no intraoperative or postoperative complications except for numbness of the face. During the 6 years of follow-up, there has been no tumor progress or recurrence. We consider that endoscopic endonasal surgery is feasible in treating trigeminal neurofibromas involving the infratemporal fossa.

Infra-Temporal and Pterygo-Palatine Fossae Tumors: A Frontier in Endoscopic Endonasal Surgery—Description of the Surgical Anatomy of the Approach and Report of Illustrative Cases

Infratemporal and pterygopalatine fossae (ITF and PPF) represent two complex paramedian skull base areas, which can be defined as jewelry boxes, containing a large number of neurovascular and osteomuscular structures of primary importance. They are in close communication with many craniofacial areas, such as nasal/paranasal sinuses, orbit, middle cranial fossa, and oral cavities. Therefore, they can be involved by tumoral, infective or inflammatory lesions spreading from these spaces. Moreover, they can be the primary site of the development of some primitive tumors. For the deep-seated location of ITF and PPF lesions and their close relationship with the surrounding functional neuro-vascular structures, their surgery represents a challenge. In the last decades, the introduction of the endoscope in skull base surgery has favored the development of an innovative anterior endonasal approach for ITF and PPF tumors: the transmaxillary-pterygoid, which gives a direct and straightforward route for these areas. It has demonstrated that it is effective and safe for the treatment of a large number of benign and malignant neoplasms, located in these fossae, avoiding extensive bone drilling, soft tissue demolition, possibly unaesthetic scars, and reducing the risk of neurological deficits. However, some limits, especially for vascular tumors or lesions with lateral extension, are still present. Based on the experience of our multidisciplinary team, we present our operative technique, surgical indications, and pre- and post-operative management protocol for patients with ITF and PPF tumors.

Anatomical Computerized Exploration to Excise Malignancies in Deep Facial Compartments: An Advanced Virtual Reality Protocol for a Tailored Surgical Approach

Objective/Hypothesis

This study describes the design and application of a novel advanced protocol for virtual three-dimensional anatomical reconstruction of the deep facial compartments, aiming to improve the preoperative understanding and the intraoperative assistance in complex resective surgeries performed for malignant diseases which extend in complex spaces, including the pterygomaxillopalatine fossa, the masticator space, and the infratemporal fossa.

Methods

This study is a non-profit, retrospective, and single-institution case series. The authors clearly describe in detail imaging acquisition protocols which are suitable to segment each target, and a multilayer reconstruction technique is presented to simulate anatomical structures, with particular focus on vascular networks. Virtual surgical planning techniques are individually designed for each case to provide the most effective access to the deep facial compartments. Intraoperative guidance systems, including navigation and virtual endoscopy, are presented, and their role is analyzed.

Results

The study included seven patients with malignant disease located in the deep facial compartments requiring radical resection, and all patients underwent successful application of the protocol. All lesions, except one, were subject to macroscopically radical resection. Vascular structures were identified with overall reconstruction rates superior to 90% for major caliber vessels. Prominent landmarks for virtual endoscopy were identified for each case.

Conclusions

Virtual surgical planning and multilayer anatomical reconstruction are valuable methods to implement for surgeries in deep facial compartments, providing the surgeon with improved understanding of the preoperative condition and intraoperative guidance in critical phases for both open and endoscopic phases. Such techniques allow to tailor each surgical access, limiting morbidity to strictly necessary approaches to reach the disease target.

Combined endoscopic endonasal and transorbital multiportal approach for complex skull base lesions involving multiple compartments

PURPOSE

This study defines the specific areas that connect the surgical corridors of the endoscopic endonasal (EEA) and transorbital approach (TOA) to identify adequate clinical applications and perspectives of this combined multiportal approach.

METHODS

Consecutive patients who underwent combined EEA and TOA procedures for various pathologies involving multiple compartments of the skull base were enrolled.

RESULTS

A total of eight patients (2 chondrosarcomas, 2 meningiomas, 2 schwannomas, 1 glioma, and 1 traumatic optic neuropathy) were included between August 2016 and April 2021. The cavernous sinus (CS) was targeted as the connection area of the combined approach in four patients with tumors infiltrating the middle cranial fossa (MCF) and central skull base through the CS. For two patients with MCF tumors extending into the infratemporal fossa (ITF), the horizontal portion of the greater sphenoid wing and the foramen ovale were utilized as the connection area. In the remaining 2 patients, connection was achieved through the optic canal (OC). Gross total and near total resection was achieved in 5 patients with tumors, and circumferential removal of bone composing the OC was performed in one patient with traumatic compressive optic neuropathy. Postoperative complications included one cardiac arrest due to underlying cardiovascular disease and one case of oculomotor nerve palsy.

CONCLUSIONS

The combined EEA and TOA procedure is a useful strategy for complex lesions involving multiple compartments of the skull base. Herein, we identified the specific areas connecting the two surgical approaches, allowing a common path for EEA and TOA procedures.