Orbit malar construction with vascularized bone graft

The typical deformity of TCS is a lateral cleft through the orbit and zygoma, with loss of ocular support. This is corrected utilizing bone grafts.

The zygomatico-orbital complex is best approached through a coronal approach. When choosing the location of the incision, an eventual ear construction should be considered.

It is imperative that the plane of dissection in the area where the bone graft will be harvested is supra periosteal.

Access to the orbital floor is gained through a lower eyelid transconjunctival approach.

A complete circumferential subperiosteal dissection of the orbit and periorbital skeleton is performed.

The following pages provide general information regarding orbital anatomy and dissection

• Preoperative considerations
• Anatomy of the bony orbit
• Correlation of surface and cross sectional anatomy
• Introduction to periorbital dissection
• Orbital floor dissection
• Medial orbital wall dissection
• Lateral orbital wall dissection
• Orbital roof dissection
• Adjunctive access procedures (orbitotomies)
• Retrobulbar hemmorage

A template of the proposed zygomatic complex is made and taken to the skull. A T-shape calvarial bone graft serving to reconstruct the body of the zygoma, zygomatic arch, and the inferior orbital rim is outlined with an electrocautery needle through the periosteum.

The vascularity or blood supply of the bone graft is based on the temporalis pedicle and around 2/3 of the bone harvested for the horizontal arm of the T should be attached to the temporalis muscle.

Parallel incisions through the temporalis muscle to allow mobilization of the pedicled bone graft are necessary.

A small tunnel/portion of the muscle is elevated at the inferior osteotomy line to allow for the osteotomy.

One burr hole is made and the desired shaped graft is harvested using a craniotome. Care is taken not to damage the periosteum overlaying the bone flap.

The bone flap is carefully lifted making sure that no dural lacerations occur.

The periosteum must remain attached to the bone and can be facilitated by drilling small holes at the periphery of the graft and suturing it in place.

A split thickness cranial bone graft is harvested from an adjacent area of the skull for the reconstruction of the lateral orbital wall/floor/rim. Harvesting of split thickness cranial bone is described in the coronal approach.

The lateral and infraorbital rims may need to be adjusted to conform to the corresponding regions of the bone graft. This can be done by the use of saws and burrs.

The bone graft is then rotated into position and attached with plates and screws to the zygoma and lateral orbital rim (resorbable plates and screws in children). The neo-orbital rim is trimmed and smoothened with a contouring burr.

The prolapsed contents of the orbit are separated and retrieved from the inferior orbital fissure or cleft.

A split thickness cranial bone graft is adapted to cover the internal orbital defects and may be secured either with screw fixation only or with plate and screw fixation (as illustrated). Resorbable plate and screw fixation is recommended in children.

Reconstruction of the donor defect is necessary not only to restore the contour but to protect the brain. Reconstructive options include split thickness calvarial bone graft, cranial bone graft shavings in children, and titanium mesh, porous polyethylene or polymethylmethacrylate (PMMA) in adults.

Cranial reconstruction in adults is discussed in the section on postablative reconstruction.

Apply ice packs (may be effective in a short term to minimize edema).

Eye lid incisions should be kept well lubricated with ophthalmic antibiotic ointment. A temporary tarsorrhaphy may be useful to help protect the globe.

The sterile dressing placed over the incisions is maintained for a minimum of 48 hours. Thereafter routine wound care should be instituted.

Antibiotic prophylaxis is continued for 1-5 days depending on the nature, complexity, and duration of the surgical procedure.

Remove sutures from skin after approximately 7-10 days if nonresorbable sutures have been used.

Regular follow up examinations to monitor healing are required.

Avoid sun exposure and tanning to skin incisions for several months.