Eye Socket (Orbit)

The eye sockets are the osseous structures containing the eye and its blood vessels, as well as the nerves and muscles that move the eyeball. This structure, on its superior side, forms part of the base of the cranium, and the interior side faces the nasal aperture and the hollow cells (sinuses) of the ethmoid bone.

On its inferior side, the eye socket forms the roof of the space (sinus) of the upper jaw (maxilla). The eye sockets are covered by the upper and lower eyelids, which protect the eyeball. Damage to the walls of the eye socket can be caused by a wound, or as a result of the removal of a tumor that penetrates and destroys the fragile osseous structure of the eye socket or the soft tissue surrounding it. Reconstruction of the osseous structure is sometimes important to restore the symmetry of the face, and sometimes in order to restore balance between the eyes. Reconstruction of the soft tissue surrounding this structure is important for the covering of the osseous structure, or, similar to the reconstruction of the eyelid, for the protection of the eyeball. In cases where the eyeball is lacking, it is important to preserve the eye socket in order to enable the introduction of a suitable prosthetic eye.

Osseous reconstruction is possible by using cranial bone that is moved as a bone graft or as a bone flap together with the blood vessels which supply it. The choice between these two options is usually determined by the condition of the patient. In any case, they can each only use a relatively small quantity of bone, and the potential for shaping the bone is limited when the defect is three dimensional and complex. In this type of defect, synthetic implants are usually used, with a titanium mesh that can be molded intra-operatively for an optimum fit to the defect, or as a custom-made implant designed with CT imaging from polyethylene (Medpor), or from a methyl methacrylate polymer and calcium hydroxide (HTR). The use of such implants is possible only in cases where there is a defect prior to the reconstructive surgery. In instances where there is a need to repair a defect in one of the walls of the eye socket, it is possible to use sheets of cartilage that are taken from the cartilaginous nasal septum. Likewise, it is possible to use synthetic implants for the purpose of providing internal support to the eye socket. 

The roof of the eye socket is unique in that it is also the local base of the skull, and therefore requires a reconstruction that will prevent the cerebral tissue from descending into the orbit, or the dripping of cerebro-spinal fluid (CSF), which is accompanied by the danger of life-threatening infection of the cerebral meninges or the brain itself. In these cases, it is necessary to fully seal the base of the skull using appropriate soft tissues. The meninges in this area can be repaired by implanting a thin sheet of the connective tissue that envelopes the muscles of the thigh and is sewn onto the borders of the defect within the brain envelope sheath (dura) overlying the roof of the orbit. In such cases, it is also necessary to add an additional protective layer to the area by rotating the temporalis muscle from the temporal cranial area, or by free transferring a section of muscle with the blood vessels supplying it, and connecting it to the recipient blood vessels in the area of the temple using microsurgical techniques. It is also possible to transfer muscle envelope connective tissue from the thigh, with the blood vessels supplying it, as a free flap and therefore achieve a multi-layered reconstruction with direct blood supply.

In all cases where osseous reconstruction is performed, it is important to reconstruct the local cover with soft tissue. It is possible to use flaps of soft tissue that can be transferred from the area of the temporal bone or scalp. Not infrequently, the need arises to transfer free flaps of muscle or skin along with the blood vessels supplying them, which are then connected to recipient blood vessels in the area using microsurgical techniques.

Full reconstruction of the eyelids is extremely complex, and it is difficult to achieve full functionality of these delicate structures. Partial reconstruction of the eyelids is possible by using local flaps from the neighboring eyelid or from proximal areas such as the forehead or temple. In certain cases, it is also necessary to make use of cartilage grafts taken from the cartilaginous nasal septum or from cartilage taken from the ears to support the reconstructed eyelids. In those cases where the eyeball is lacking, in addition to the lack of eyelids, reconstruction with an eyeball prosthetic is not possible, and therefore it is optional to reconstruct using an external prosthetic made of silicone, which can be attached with glue or connected with metal pins fixed to the bones of the eye socket for the rapid attachment with magnets or other appropriate coupling devices.