Coronoid-Temporalis Pedicled Flap for Orbital Floor Defect Reconstruction

This protocol introduces a novel technique using a coronoid-temporalis pedicled flap for repairing small to medium orbital flow defects. The protocol involves harvesting the coronoid process with its attached temporalis muscle pedicle, transposing the flap to the orbital floor, contouring the bone to fit the defect, and achieving rigid fixation. Use a monopolar electrocautery tip to incites the posterior buccal mucosa and the overlying masseter muscle along the anterior ramus border.

Continue the dissection until the lateral surface of the mandibular ramus is exposed. Confirm visualization of the anterior ramus border and coronoid outline. Detach the masseter muscle from its bony attachment on the lateral surface of their mandibular ramus and elevate it subperiosteally.

Stop dissection once the coronoid process and its lateral surface are fully exposed. Use a reciprocating saw with a fine-toothed blade to perform a horizontal osteotomy at the coronoid base. Maintain shallow blade depth to avoid injury to the maxillary artery, located posterior to the sigmoid notch.

If the maxillary artery or its branches are inadvertently injured, immediately clamp the bleeding end with the hemostatic forceps and ligate to achieve hemostasis. Preserve the continuity of the temporalis muscle attachment during osteotomy. Identify the inferior alveolar neurovascular bundle at the osteotomy margin and clamp proximally using curved hemostatic forceps to prevent bleeding.

Grasp the harvested coronoid segment using Kocher or bone-holding forceps. Gently pose the flap superiorly to the orbital floor defect site. Rotate the segment in three dimensions to achieve optimal anatomy contouring related to the defect.

Elevate the perinasal soft tissue flap via the existing extraoral incision to expose the residual anterior maxillary wall. Smooth the residue edges of the maxillary bone or bone graft surrounding the defect to ensure flush contact with the coronoid graft. Select a one millimeter titanium mini-plate and manually contour it to conform closely to the surface of the bone at the fixation site.

Fix the plate using five millimeter length self-tapping screws with pilot holes drilled with 1.6 millimeter bit. Laterally, use a one millimeter extended-interval plate to bridge the coronoid graft and the zygomatic body. Confirm that the fixation provides firm immobilization of the flap.

Ensure that the orbital contents are adequately supported by the graft. Given the patient's combined hemi maxillectomy defect and planned postoperative radiotherapy, the latissiumus dorsi myocutaneous flap was selected to achieve three critical objectives, reconstructing maxillary volume, restoring facial contour, and providing vascularized soft tissue coverage over the titanium implants to prevent post-radiation exposure. Elevate and harvest the latissimus dorsi muscle free flap using standard technique.

Perform microvascular anastomosis between the flap vessels and the recipient vessels in the neck region under microscope magnification. Insert the flap to fill the defect in the maxillary region, ensuring full coverage of the coronoid graft and titanium hardware. Suture the distal edge of the flap to the surrounding soft tissue along the inferior optical rim using interrupted 3-0 polypropylene sutures, ensuring stable coverage of the hardware and eliminating dead space.

Suture the intraoral margin of the flap to the remaining oral mucosal edge using interrupted 3-0 absorbable sutures. We demonstrated the representative results of the protocol. The patient declared no diplopia or enopthalmos after surgery.

The facial symmetry was also basically maintained. The intraoral images showed that the soft tissue flap established an anatomical barrier between oral and nasal cavities to prevent oronasal communication. 3D reconstruction of post-operation CT scan displayed well fixes of the bone flap three months after surgery.

This article demonstrated the surgical steps of the CTPF reconstructing orbital floor defect. The results show that the CTPF could reconstruct medium to small defect of orbital floor, ensuring approximate symmetry of bilateral eyeballs. Unfortunately, due to limited bone volume, the CTPF could not reconstruct large defect of orbital floor.

For such patients, titanium mesh or free bone flap grafting may be better choices.