An Anatomical Feasibility Study for Revascularization of the Ophthalmic Artery. Part II: Intraorbital Segment

Combined Face and Whole Eye Transplantation: Cadaveric Rehearsals and Feasibility Assessment

Background

In properly selected patients, combined face and whole eye transplantation (FWET) may offer a more optimal aesthetic and potentially functional outcome while avoiding the complications and stigma of enucleation and prosthetics. This study presents the most comprehensive cadaveric assessment for FWET to date, including rehearsal allograft procurement on a brain-dead donor.

Methods

Over a 2-year period, 15 rehearsal dissections were performed on 21 cadavers and one brain-dead donor. After identification of a potential recipient, rehearsals assessed clinical feasibility and enabled operative planning, technical practice, refinement of personalized equipment, and improved communication among team members. Operative techniques are described.

Results

Facial allograft procurement closely followed previously described face transplant techniques. Ophthalmic to superficial temporal (O-ST) vessel anastomosis for globe survival was assessed. Craniectomy allowed for maximal optic nerve and ophthalmic vessel pedicle length. Appropriate pedicle length and vessel caliber for O-ST anastomosis was seen. Research procurement demonstrated collateral blood flow to the orbit and surrounding structures from the external carotid system as well as confirmed the feasibility of timely O-ST anastomosis. Personalized cutting guides enabled highly accurate bony inset.

Conclusions

This study formalizes an approach to FWET, which is feasible for clinical translation in judiciously selected patients. O-ST anastomosis seems to minimize retinal ischemia time and allow perfusion of the combined allograft on a single external carotid pedicle. Although restoration of vision likely remains out of reach, globe survival is possible.

Supraorbital artery: Anatomical variations and neurosurgical applications

Background

The supraorbital artery (SOA) originates from the ophthalmic artery in a superomedial aspect of the orbit, exiting through the supraorbital groove to emerge onto the forehead. The SOA has important neurosurgical considerations regarding different approaches and bypasses. The SOA is poorly described in the standard anatomical textbooks. Therefore, we present this article to describe the anatomical variations of the SOA and their implications on the neurosurgical field.

Methods

We conducted a literature review in PubMed and Google Scholar databases to review the existing literature describing the SOA anatomy and its neurosurgical applications.

Results

While reading the available articles and original works regarding SOA, we identified 22 studies that discuss the SOA. We noticed the anatomical variations of the SOA in terms of origin, course, diameter, branches, depth, and distance in relation to the midline and vertical glabellar line. We also discussed certain applications of SOA and its importance in neurosurgical approaches, bypass, photoplethysmography, aneurysms, and reconstruction of cranial fossa defects.

Conclusion

The variable anatomy of the SOA has a paramount impact on performing different neurosurgical approaches. Therefore, cadaveric studies of the SOA are important to explore potential methods for the preservation of the artery in different neurosurgical applications.

The entry point of the central retinal artery into the outer meningeal sheath of the optic nerve

INTRODUCTION

The entry point of the central retinal artery (CRA) into the outer meningeal sheath of the optic nerve posterior to the globe has been studied and debated for more than one hundred years. The authors have supervised an orbital anatomy course for more than two decades. This article summarizes previous studies of the CRA and presents the results of dissections of 67 orbits.

MATERIALS AND METHODS

Heads were hemisected prior to dissection at the Vagelos College of Physicians and Surgeons of Columbia University. The authors measured the entry point of the CRA with a caliper and noted the meridional orientation of the CRA.

RESULTS

The mean entry point was 10.65 mm posterior to the globe, with a range of 5 to 18 mm. Most commonly, the CRA entered the sheath in the inferior meridian, but some entered slightly inferomedially or inferolaterally.

CONCLUSIONS

The entry point of the CRA into the sheath of the optic nerve is variable, and without detailed angiography the clinician cannot know the course of the CRA prior to performing invasive intraorbital procedures. Knowledge of common variations in CRA entry into the outer meningeal sheath of the optic nerve should help to minimize injury during surgery.