Transorbital and supraorbital uniportal multicorridor approach to the orbit, anterior, middle and posterior cranial fossa: Anatomic study

Deep Temporal Muscle Pedicled Flap: A Novel Reconstruction Technique Following Transorbital Approach, Anatomic Study, and Surgical Implications

BACKGROUND AND OBJECTIVES

The temporalis muscle flap has historically been used for repairing defects from orbital procedures and is commonly used in cranial, oral, and facial reconstructions. However, its application for reconstructing the skull base after a transorbital approach has not been explored. Reconstruction after a transorbital intradural approach is still object of preclinical and clinical investigation, with various techniques emerging recently. This study introduces a novel method suitable for extensive resections of the skull base, including intradural resections of the anterior, middle, and posterior cranial fossae.The study aimed to investigate the feasibility of rotating a vascularized myofascial flap from the anterior third of the temporalis muscle onto the skull base, exploring its extension into the middle cranial fossa after drilling the greater wing of the sphenoid.

METHODS

Six endoscopic dissections were performed on formalin-fixed heads to illustrate the feasibility of preparing a deep fascia flap from the temporalis muscle. Red silicone latex was injected into the external carotid artery to confirm the vascular integrity of the deep temporal branches of the maxillary artery.

RESULTS

The deep temporalis myofascial flap offers a large, well-vascularized tissue that can be easily rotated to cover skull base defects after transorbital approaches. Its coverage extends from the middle and anterior cranial fossae to the infratemporal fossa and the lateral wall of the cavernous sinus. It also effectively covers dural defects at the temporal pole.

CONCLUSION

With an appropriate temporal bony window and sufficient exposure, it is feasible to endoscopically prepare a rotation flap from the anterior third of the temporalis muscle, minimizing the need for resecting the lateral orbital margin. This approach is a favorable alternative to traditional reconstruction techniques, offering quick setup in a single operative procedure. Future studies are needed to confirm minimal donor site morbidity regarding masticatory function.

Is It Time for a Paradigm Shift in the Surgical Management of Trigeminal Schwannomas? Evaluating the Role of the Transorbital Approach: An Anatomo-Clinical Study and Systematic Literature Review

BACKGROUND

Endoscopic transorbital approach emerged in recent years as an effective, minimally invasive route to access Meckel's cave area. Several case series proved its effectiveness in the surgical treatment of trigeminal schwannomas. This route provides the advantages of a minimally invasive approach associated with low morbidity rates. In this anatomo-clinical study we illustrate the usefulness of the superior eyelid transorbital approach for the surgical treatment of trigeminal schwannoma guiding the clinical applicability of the anatomical findings into real surgical practice.

METHODS

Superior eyelid transorbital endoscopic approach was performed on 8 cadaveric specimens, and the surgical results were confirmed in a retrospective review of all the surgical cases of transorbital surgery performed by the senior authors providing an illustrative case. Finally, we performed a literature review of all the case series of trigeminal schwannomas operated through an endoscopic transorbital approach.

RESULTS

Stepwise dissection was divided in 3 phases: skin, endo-orbital, and endocranial. The illustrative case provided demonstrate gross total resection of a cavernous sinus type trigeminal schwannomas treated through this route. Literature review revealed 68 cases of trigeminal schwannomas that were successfully treated using the transorbital approach.

CONCLUSIONS

The endoscopic transorbital approach may offer a valuable alternative for the surgical treatment of trigeminal schwannomas. This technique provides a minimally invasive, direct and natural "interdural" route to the lateral wall of the cavernous sinus and Meckel's cave.

Endoscopic transorbital approach for recurrent spheno-orbital meningiomas: single center case series

Endoscopic transorbital approaches (ETOAs) are finding wide application for skull base lesions, particularly for spheno-orbital meningiomas (SOMs). These tumors have high recurrence rates, and second surgery can often represent a challenge. In this study we analyze our experience of management of recurrent SOMs through a slightly modified eyelid crease approach. Between May 2016 and September 2023, in the Department of Neurosurgery of Fondazione IRCCS Policlinico San Matteo (Pavia, Italy), five consecutive recurrent SOMs have been treated using an endoscopic transorbital approach. Demographic data, preoperatory deficits, lesions characteristics, histology, grade of resection, eventual adjuvant treatments, complications, outcome in terms of symptoms improvement and cosmesis, and hospitalization are described. One patient maintained a right lateral rectus muscle palsy that was already present in the preoperatory, no cerebrospinal fluid (CSF) leaks were reported. All patients had postoperative periorbital edema, but no other systemic complication was found. All patients had proptosis improvement, two had visual acuity improvement, and best cosmetic outcome was obtained in all cases. Hospitalization varied between 4 and 6 days. ETOAs in the management of recurrent SOMs are safe and have good outcome. Right selection of patients is mandatory, but when feasible, endoscopic surgery can allow a virgin route to a previously operated tumor, guaranteeing a good strategic option.

The Transorbital Approach: A Comprehensive Review of Targets, Surgical Techniques, and Multiportal Variants

The transorbital approach (TOA) is gaining popularity in skull base surgery scenarios. This approach represents a valuable surgical corridor to access various compartments and safely address several intracranial pathologies, both intradurally and extradurally, including tumors of the olfactory groove in the anterior cranial fossa (ACF), cavernous sinus in the middle cranial fossa (MCF), and the cerebellopontine angle in the posterior cranial fossa (PCF). The TOA exists in many variants, both from the point of view of invasiveness and from that of the entry point to the orbit, corresponding to the four orbital quadrants: the superior eyelid crease (SLC), the precaruncular (PC), the lateral retrocanthal (LRC), and the preseptal lower eyelid (PS). Moreover, multiportal variants, consisting of the combination of the transorbital approach with others, exist and are relevant to reach peculiar surgical territories. The significance of the TOA in neurosurgery, coupled with the dearth of thorough studies assessing its various applications and adaptations, underscores the necessity for this research. This extensive review delineates the multitude of target lesions reachable through the transorbital route, categorizing them based on surgical complexity. Furthermore, it provides an overview of the different transorbital variations, both standalone and in conjunction with other techniques. By offering a comprehensive understanding, this study aims to enhance awareness and knowledge regarding the current utility of the transorbital approach in neurosurgery. Additionally, it aims to steer future investigations toward deeper exploration, refinement, and exploration of additional perspectives concerning this surgical method.

Transorbital approach to the cavernous sinus: an anatomical study of the related cranial nerves

Background

The cavernous sinus (CS) is a demanding surgical territory, given its deep location and the involvement of multiple neurovascular structures. Subjected to recurrent discussion on the optimal surgical access, the endoscopic transorbital approach has been recently proposed as a feasible route for selected lesions in the lateral CS. Still, for this technique to safely evolve and consolidate, a comprehensive anatomical description of involved cranial nerves, dural ligaments, and arterial relations is needed.

Objective

Detailed anatomical description of the CS, the course of III, IV, VI, and V cranial nerves, and C3-C7 segments of the carotid artery, all described from the ventrolateral endoscopic transorbital perspective.

Methods

Five embalmed human cadaveric heads (10 sides) were dissected. An endoscopic transorbital approach with lateral orbital rim removal, anterior clinoidectomy, and petrosectomy was performed. The course of the upper cranial nerves was followed from their apparent origin in the brainstem, through the middle fossa or cavernous sinus, and up to their entrance to the orbit. Neuronavigation was used to follow the course of the nerves and to measure their length of surgical exposure.

Results

The transorbital approach allowed us to visualize the lateral wall of the CS, with cranial nerves III, IV, V1-3, and VI. Anterior clinoidectomy and opening of the frontal dura and the oculomotor triangle revealed the complete course of the III nerve, an average of 37 (±2) mm in length. Opening the trigeminal pore and cutting the tentorium permitted to follow the IV nerve from its course around the cerebral peduncle up to the orbit, an average of 54 (±4) mm. Opening the infratrochlear triangle revealed the VI nerve intracavernously and under Gruber's ligament, and the extended petrosectomy allowed us to see its cisternal portion (27 ± 6 mm). The trigeminal root was completely visible and so were its three branches (46 ± 2, 34 ± 3, and 31 ± 1 mm, respectively).

Conclusion

Comprehensive anatomic knowledge and extensive surgical expertise are required when addressing the CS. The transorbital corridor exposes most of the cisternal and the complete cavernous course of involved cranial nerves. This anatomical article helps understanding relations of neural, vascular, and dural structures involved in the CS approach, essential to culminating the learning process of transorbital surgery.