Endoscopic transorbital ligation of the maxillary artery through the inferior orbital fissure

Inferior orbital fissure release to access the inferolateral orbital apex

OBJECTIVE

To describe release of the inferior orbital fissure (IOF) as a novel surgical technique that will improve access to the inferior and inferolateral orbital apex.

DESIGN

Laboratory investigation.

PARTICIPANTS

Human cadaver heads.

METHODS

Cadaveric dissection study whereby the technique of an IOF release was performed. A swinging eyelid preseptal approach was used to enable a subperiosteal dissection to the orbital floor without obstruction from orbital fat prolapse. A plane was dissected between periorbita and Muller's muscle, the smooth muscle that overlies the entire length of the IOF. Measurements were taken in the sagittal plane from a point on the inferior orbital rim directly above the infraorbital foramen to the most posterior aspect of the orbital floor.

RESULTS

Fifteen orbits from 8 cadaver heads were dissected with the aid of a rigid 0-degree endoscope and microsurgical instruments. This study demonstrated that an additional 10.93 ± 2.10 mm of access to the orbital apex was gained after the release of periorbita from the IOF.

CONCLUSION

We propose that the IOF release can be adopted as an adjunctive technique to orbital surgery of the inferior and inferolateral orbital apex.

Surgical Anatomy of the Microscopic and Endoscopic Transorbital Approach to the Middle Fossa and Cavernous Sinus: Anatomo-Radiological Study with Clinical Applications

BACKGROUND

The transorbital approaches (TOAs) have acquired growing notoriety, thanks to their ability to offer alternative corridors to the skull base. However, the limited access and the unfamiliarity with this surgical perspective make recognition of key landmarks difficult, especially for less experienced surgeons. The study wants to offer a detailed description of the anatomy to comprehend the potential and limitations of TOAs.

METHODS

Measurements of the orbit region and the surrounding areas were performed on two hundred high-resolution CT scans and thirty-nine dry skulls. Five specimens were dissected to illustrate the TOA, and one was used to perform the extradural clinoidectomy. Three clinical cases highlighted the surgical applications.

RESULTS

A step-by-step description of the key steps of the TOA was proposed and a comparison with the transcranial anterior clinoidectomy was discussed. The mean work distance was 6.1 ± 0.4 cm, and the lateral working angle increased 20 ± 5.4° after removing the lateral orbital rim.

CONCLUSIONS

TOAs are indicated in selected cases when tumor involves the lateral portion of the cavernous sinus or the middle skull base, obtaining a direct decompression of the optic nerve and avoiding excessive manipulation of the neurovascular structures. Comprehension of surgical anatomy of the orbit and its surrounding structures is essential to safely perform these approaches.

Through the orbit and beyond: Current state and future perspectives in endoscopic orbital surgery on behalf of the EANS frontiers committee in orbital tumors and the EANS skull base section

Introduction

Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery.

Research question

Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection.

Material and methods

A PRISMA based literature search was performed to select the most relevant papers on the topic.

Results

Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery.

Discussion and conclusion

This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.

Transuncal Selective Amygdalohippocampectomy by an Inferolateral Preseptal Endoscopic Approach Through Inferior Eyelid Conjunctival Incision: An Anatomic Study

BACKGROUND

Transorbital endoscopic approaches have been described for pathologies of anterior and middle fossae. Standard lateral orbitotomy gives access to mesial temporal lobe, but the axis of work is partially obscured by the temporal pole and working corridor is limited.

OBJECTIVE

To evaluate the usefulness of an inferolateral orbitotomy to provide a more direct corridor to perform a transuncal selective amygdalohippocampectomy.

METHODS

Three adult cadaveric specimens were used for a total of 6 dissections. A step-by-step description and illustration of the transuncal corridor for a selective amygdalohippocampectomy were performed using the inferolateral orbitotomy through an inferior eyelid conjunctival incision. The anatomic landmarks were demonstrated in detail. Orbitotomies and angles of work were measured from computed tomography scans, and the area of resection was illustrated by postdissection MRI.

RESULTS

Inferior eyelid conjunctival incision was made for exposure of the inferior orbital rim. Inferolateral transorbital approach was performed to access the transuncal corridor. Endoscopic selective amygdalohippocampectomy was performed through the entorhinal cortex without damage to the temporal neocortex or Meyer's loop. The mean horizontal diameter of the osteotomy was 14.4 mm, and the vertical one was 13.6 mm. The mean angles of work were 65° and 35.5° in the axial and sagittal planes, respectively. Complete amygdalohippocampectomy was achieved in all 6 dissections.

CONCLUSION

Transuncal selective amygdalohippocampectomy was feasible in cadaveric specimens using the inferolateral transorbital endoscopic approach avoiding damage to the temporal neocortex and Meyer's loop. The inferior eyelid conjunctival incision may result in an excellent cosmetic outcome.

Recent progress in endoscopic skull base surgery: Functional preservation and multiportal approaches

Over the past couple of decades, endoscopic skull base surgery (ESBS) has significantly evolved and is applied to a broad range of skull base pathologies, including sinonasal malignancies. Recent studies have demonstrated remarkable progress of ESBS in complete resection with low morbidity and extension of its application to larger and more complex lesions. In this review, we focus on the evolution of functional preservation and multiportal approaches. Progress in preoperative assessments and surgical techniques improved the preservation of olfactory function after ESBS. The technical feasibility of olfaction preservation even after resection of olfactory groove lesions has been reported. To overcome the limitations of extending use of the endoscopic endonasal approach in surgical fields, various types of multiportal approaches, including combinations of the endoscopic endonasal and transorbital, transmaxillary, or transoral approach, have been reported, as they are useful for complete resection of extensive pathologies while limiting morbidity. These innovative techniques are still in the process of maturation. Hence, an ongoing critical evaluation is essential to ensure efficacy.