Facial Transplantation: An Anatomic and Surgical Analysis of the Periorbital Functional Unit:

Microanatomy of the Temporal Division of the Facial Nerve in the Periorbital Region Applied to Minimally Invasive Keyhole Approaches

BACKGROUND

Minimally invasive keyhole approaches to the anterior skull base and circle of Willis require small incisions near distal branches of the temporal division (TD) of the facial nerve. Few studies have focused on planning the incision to avoid the TD branches and maximize exposure in these approaches. This study aimed to define a safe zone away from the TD branches for skin incision during minimally invasive keyhole approaches using reliable and practical skin landmarks.

METHODS

In 5 cadaveric heads (10 sides), a Cartesian system was established with the orbitomeatal line connecting the lateral canthus and the external acoustic meatus (x-axis). A perpendicular line was drawn to the x-axis at the lateral canthus (y-axis). TD branches were dissected proximally to distally until the nerve-muscle junction of the orbicularis oculi and fronto-occipitalis muscles. Nerve-muscle junction points were registered in the Cartesian system. Probabilistic heat maps were generated to define a periorbital safe zone.

RESULTS

A median of 3 branches each innervated the orbicularis oculi and fronto-occipitalis. A semicircular area centered on the lateral canthus with a radius of 10 mm was found to have low (<10%) chance of containing a TD branch. This safe zone could be extended posteriorly to 15 mm inferior to the orbitomeatal line.

CONCLUSIONS

Identifying a safe zone for preserving TD branches is crucial for surgical incisions planned in the superolateral region of the orbit. This study provides a clinically applicable and reproducible landmark for planning incisions commonly used during minimally invasive keyhole approaches.

Donors for nerve transplantation in craniofacial soft tissue injuries

Neural tissue is an important soft tissue; for instance, craniofacial nerves govern several aspects of human behavior, including the expression of speech, emotion transmission, sensation, and motor function. Therefore, nerve repair to promote functional recovery after craniofacial soft tissue injuries is indispensable. However, the repair and regeneration of craniofacial nerves are challenging due to their intricate anatomical and physiological characteristics. Currently, nerve transplantation is an irreplaceable treatment for segmental nerve defects. With the development of emerging technologies, transplantation donors have become more diverse. The present article reviews the traditional and emerging alternative materials aimed at advancing cutting-edge research on craniofacial nerve repair and facilitating the transition from the laboratory to the clinic. It also provides a reference for donor selection for nerve repair after clinical craniofacial soft tissue injuries. We found that autografts are still widely accepted as the first options for segmental nerve defects. However, allogeneic composite functional units have a strong advantage for nerve transplantation for nerve defects accompanied by several tissue damages or loss. As an alternative to autografts, decellularized tissue has attracted increasing attention because of its low immunogenicity. Nerve conduits have been developed from traditional autologous tissue to composite conduits based on various synthetic materials, with developments in tissue engineering technology. Nerve conduits have great potential to replace traditional donors because their structures are more consistent with the physiological microenvironment and show self-regulation performance with improvements in 3D technology. New materials, such as hydrogels and nanomaterials, have attracted increasing attention in the biomedical field. Their biocompatibility and stimuli-responsiveness have been gradually explored by researchers in the regeneration and regulation of neural networks.

Evaluation of facial artery course variations and depth by Doppler ultrasonography

BACKGROUND

As deep nasolabial folds (NLF) are associated with facial aging, there is an increasing demand for esthetic correction with filler injections. Understanding the anatomy of the angular artery (AA) and facial artery (FA) around the NLF region is essential for ensuring the safety of dermal filler injections into the NLF. The purpose of this study was to provide detailed vascular anatomical information on the course and depth of AA and FA around NLF using Doppler ultrasound on live cases.

METHODS

FA was observed from the origin level adjacent to the mandible corpus to the end of its terminal branch AA in 168 hemifaces of 84 cases with Doppler ultrasonography.

RESULTS

We made a classification of the FA course based on the NLF. The minimum and maximum depths of the FA along its course were measured in 84 cases. The results showed that its course may be highly superficial (2.5 mm at the mandibular origin, 3.7 mm at the cheilion, 3.7 mm at the nasal ala) or it may follow a very deep course near the periosteum (15.0 mm at the mandibular origin, 18.7 mm at the cheilion, 23.5 mm at the nasal ala). FA depth was varied between 5.98 mm and 6.62 mm at the mandibular origin, between 8.36 mm and 9.20 mm at the cheilion, between 9.52 mm and 10.51 mm at the nasal ala at a 95% confidence interval.

CONCLUSIONS

This study suggests that there is no absolutely safe depth or region for nasolabial fold filler injections.

Anatomic study of the arterial territories of the face depending on the external carotid artery branches

AIM OF THE STUDY

Blood supply of the skin of the face is mainly provided by 3 branches of the external carotid artery: facial artery (FA), superficial temporal artery (STA) and transverse facial artery (TFA) which is a branch of the STA. The aim of the study was to describe the arterial territories of the skin of the face depending on the external carotid branches.

MATERIAL AND METHODS

After dissection of the first two centimeters of these arteries on one side, we performed an injection of India ink of different colors in the arteries in order to describe the arterial territories (angiosomes) of the face on 24 embalmed cadavers.

RESULTS

The lips and the tip of the nose were vascularized in most cases by the FA. The STA vascularizes the temporal and frontal areas and a part of the auricle. The buccal area blood supply is coming from the FA with a participation of the TFA which is variable (10/24 cases), and the zygomatic area blood supply is coming from the STA with a participation of the TFA (9/24 cases).

CONCLUSIONS

Variations in the angiosomes of the face have to be considered in reconstructive surgery, and in face transplantation.

Treatment of Periorbital and Palpebral Arteriovenous Malformations

Objectives: To clarify clinically challenging palpebral arteriovenous malformations (AVMs) and to propose a novel therapeutic modality, we developed a multi-disciplinary approach for the management of AVMs with ulcer. Approach: First, the central retinal artery was secured with embolization by the transophthalmic arterial, a terminal branch of the internal carotid artery (ICA), and then, the branches of the external carotid artery (ECA) were embolized to cause a response in the AVM vasculature followed by sclerotherapy and surgery. Results: Over a 3-year follow-up of palpebral and periorbital AVMs in four females and one male 20 to 50 years of age with a mean age of 38 years, complete remission of the lesions were seen with no major complication, such as blindness, ptosis, or cerebral infarction, with functionally sound and esthetically acceptable results, with no recurrence or worsening even with one case of ulceration postembolization. Innovation: Planned treatment of palpebral and periorbital AVMs, which have been often left untreated because of their complex vasculature and a risk of total blindness due to occlusion of the central retinal artery. A "wait-and-watch" approach is frequently taken. It is important to secure the periphery to the bifurcation of the central retinal artery of the ICA, and then, embolization through the ECA results in complete remission of the lesion, followed by sclerotherapy and surgery, which are successful both in terms of function and esthetics. Conclusion: First, securing the central retinal artery leads to safer and complete resolution of palpebral and periorbital AVMs; wounding or therapeutic complications such as skin necrosis may be seen, but this approach results in complete remission in 3 years with no major complications.

Nose and Lip Graft Variants: A Subunit Anatomical Study

BACKGROUND

In the field of vascularized composite tissue allotransplantation, the surgical design of facial subunit grafts is an evolving concept. The purpose of the present article is to study the possibility of dividing the historical nose and lip face transplant into several morphologic and functional subunit grafts, depending on their respective supply.

METHODS

This study was conducted in 20 adult cadavers. The facial artery and its branches were dissected bilaterally in 16 fresh and four embalmed heads. Nasolabial perfusion was assessed by selective injection of methylene blue and eosin (n = 2) or India ink (n = 2) in the superior labial and distal facial arteries. Dynamic perfusion through the distal facial artery was illustrated by fluoroscopy (n = 3). Three nose-upper lip grafts were harvested and injected with barium sulfate for microangiography computed tomographic analysis. Finally, three isolated nasal and bilabial grafts were procured and their vascular patency assessed by fluoroscopy.

RESULTS

The distal facial artery can perfuse the entire nose, septum, and upper lip, without any contribution of the superior labial artery. A dense anastomotic network indeed exists between the respective distal rami of both vessels. Furthermore, the exclusion of the superior labial artery from the harvested nasal subunit allowed safe bilabial subunit procurement, from the same specimen.

CONCLUSIONS

The authors' results demonstrate the feasibility of harvesting nasal and labial subunits, in an isolated or a combined manner. These results can find applications in subunit autologous replantation, allotransplantation, allogenic face partial retransplantation, and the emerging field of vascularized composite tissue engineering.

Optimizing Reconstruction with Periorbital Transplantation: Clinical Indications and Anatomic Considerations

Complex periorbital subunit reconstruction is challenging because the goals of effective reconstruction vary from one individual to another. The purpose of this article is to explore the indications and anatomic feasibility of periorbital transplantation by reviewing our institutional repository of facial injury.

METHODS

Institutional review board approval was obtained at the R Adams Cowley Shock Trauma Center for a retrospective chart review conducted on patients with periorbital defects. Patient history, facial defects, visual acuity, and periorbital function were critically reviewed to identify indications for periorbital or total face (incorporating the periorbital subunit) vascularized composite allotransplantation. Cadaveric allograft harvest was then designed and performed for specific patient defects to determine anatomic feasibility. Disease conditions not captured by our patient population warranting consideration were reviewed.

RESULTS

A total of 7 facial or periorbital transplant candidates representing 6 different etiologies were selected as suitable indications for periorbital transplantation. Etiologies included trauma, burn, animal attack, and tumor, whereas proposed transplants included isolated periorbital and total face transplants. Allograft recovery was successfully completed in 4 periorbital subunits and 1 full face. Dual vascular supply was achieved in 5 of 6 periorbital subunits (superficial temporal and facial vessels).

CONCLUSIONS

Transplantation of isolated periorbital structures or full face transplantation including periorbital structures is technically feasible. The goal of periorbital transplantation is to re-establish protective mechanisms of the eye, to prevent deterioration of visual acuity, and to optimize aesthetic outcomes. Criteria necessary for candidate selection and allograft design are identified by periorbital defect, periorbital function, ophthalmologic evaluation, and defect etiology.

Morphometrical aspect on angular branch of facial artery

Anatomic variability and anastomosis of the angular artery of the facial artery with the other arteries are important for both anatomists and surgeons. In particular, the angular artery is a significant landmark in dacryocystorhinostomy. Because of variations on anatomy of the angular artery, there are limited numbers of anatomic studies on the flaps of facial region. Hence, the aim of the cadaveric study was to evaluate the anatomic features of the angular artery in detail to help surgical procedures.The artery was represented under ×4 loop magnification in 32 sides of 16 formalin-fixed adult cadavers. The angular artery's position, diameter, and branch patterns relevant to the nose arterial supply were evaluated. The facial artery ended symmetrically in 10 (62.5%) of the cadavers. The facial artery was terminated as angular artery in all of the cases. The types of the angular artery were as follows: classical angular type in 8 cases (25.0%), nasal type in 15 cases (46.9%), alar type in 4 cases (12.5%), and labial type in 5 cases (15.6%) on the facial halves. We studied the topographic anatomic features of the angular artery for increasing reliability of the flaps on the region. The angular arterial anatomic details are critical and essential for surgical cosmetic and functional results.

A functional periorbital subunit allograft: vascular, anatomic, and technical considerations for future subunit facial transplantation

BACKGROUND

Injury to the face can result in the loss of critical specialized structures (the eyelids, lips, ears and nose). Vascularized composite allotransplantation (VCA) allows the surgeon to replace exactly what has been lost. The success of the clinical face transplants suggests the possibility of transplanting specialized units of the face. In this study we explore the neurovascular anatomy and technical specifics for harvest of a functional composite eyelid subunit flap.

METHODS

12 fresh cadaver heads were studied, each yielding two flaps (N = 24). The facial (FA) and superficial temporal arteries (STA) were cannulated and injected with a gelatin/acrylic dye mixture. 6 cadaver heads were evaluated via high-resolution three-dimensional CT scans with contrast.

RESULTS

The dye injected into the STA uniformly stained the tissue of the eyelid/periorbital subunit. Injection into the FA resulted in staining of the skin and soft tissues in the medial canthal region and superior eyelid skin in 66% of specimens. CT scan studies confirm our findings with injection into the STA resulting in contrast infiltration of the palpebral arterial arcades in all cases. Injection of the FA resulted in contrast infiltration of the palpebral arterial arcades in 2 of 3 cases.

CONCLUSIONS

Based this study, a periorbital flap can be based on the STA. Motor innervation of the flap is via the zygomatic and buccal branches of the facial nerve with sensory innervation via the infraorbital, supraorbital and supratrochlear nerves. FA could be used, but its ability to perfuse the entire flap was inconsistent.