Coronoid-Temporalis Pedicled Flap for Orbital Floor Defect Reconstruction

Summary

This protocol presents a novel coronoid-temporalis pedicled flap (CTPF) technique for reconstructing small-to-medium orbital floor defects. CTPF avoids microvascular risks while maintaining biomechanical stability. Clinical cases demonstrate effective structural restoration, reduced complications, and preserved facial symmetry, offering a viable alternative to traditional grafts or alloplastic materials.

Abstract

Orbital floor defects may result from maxillary trauma or tumor resection. Traditional reconstruction techniques often rely on vascularized or non-vascularized free bone grafts, which carry risks of graft failure due to thrombosis, infection, or poor integration. This protocol introduces a novel technique using a coronoid-temporalis pedicled flap (CTPF) for repairing small-to-medium orbital floor 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. When soft tissue coverage is insufficient, additional options such as local advancement or free flaps can be employed. The CTPF technique offers a biomechanically stable, vascularized solution that avoids the complications associated with microvascular anastomosis. It is particularly suitable for moderate defects, though it may not provide sufficient volume for large or complex orbital reconstructions. A representative clinical case illustrates the technical feasibility of this approach and demonstrates anatomic restoration with preservation of facial contour. While quantitative outcomes are not reported, the procedure shows potential as a viable alternative to conventional bone grafts or alloplastic implants.

Introduction

The orbital floor, anatomically formed by the orbital plates of the maxilla, zygomatic bone, and palatine bone, serves as the principal scaffold for orbital soft tissue support. Defects in this region, commonly resulting from tumor resection or trauma, often lead to enophthalmos and diplopia due to loss of structural continuity¹. Current reconstructive approaches primarily rely on two strategies: alloplastic materials (e.g., titanium mesh) or autologous free bone flaps (e.g., fibula or iliac crest grafts)^2,3,4. Titanium mesh, despite its intraoperative malleability, carries risks of long-term complications including material fatigue, displacement, and foreign body reactions⁵. Structural fatigue fractures may traumatize intraorbital soft tissues, precipitating enophthalmos and diplopia, while chronic inflammatory responses to the implant can lead to titanium plate exposure due to progressive tissue necrosis. Free bone flaps, though avoiding synthetic material-related issues, require microvascular anastomosis with inherent risks of thrombosis, donor-site morbidity, and prolonged operative time^6,7.

To address these limitations, we developed a novel technique: the coronoid-temporalis pedicled flap (CTPF). This method utilizes the coronoid process's spatial proximity to the orbital floor and its intrinsic biomechanical strength as a load-bearing bone. Figure 1 demonstrates the surgical steps of harvesting and transposing the CTPF to the orbital floor. By preserving the natural vascular supply through intact temporalis muscle attachments, the CTPF eliminates dependence on microsurgical anastomosis while maintaining osteogenic viability.

The technique is most applicable to isolated, small-to-medium anterior orbital floor defects that do not involve the medial orbital wall or posterior floor. It is not recommended for large, complex defects requiring significant volume or multi-wall reconstruction due to anatomic limitations of flap reach and size.

Our representative clinical case demonstrates that this pedicled flap enables anatomically sound orbital reconstruction with minimal donor-site morbidity. While this approach offers a promising alternative to traditional grafting or alloplastic materials, quantitative outcome data are not yet available, and further studies are warranted to validate long-term effectiveness.

Protocol

This research is approved by the institutional Ethics Board of West China Hospital of Stomatology (protocol approval number: WCHSIRB-D-2022-343), with informed consent obtained.

1. Dissection of the coronoid process

1. Anatomical identification and initial exposure
   1. Palpate the anterior border of the mandibular ramus intraorally using the index finger.
   2. Use a monopolar electrocautery tip (set to 25-30 watts coagulation mode) to incise the posterior buccal mucosa and the overlying masseter muscle along the anterior ramus border.
   3. Continue the dissection until the lateral surface of the mandibular ramus is exposed. Confirm visualization of the anterior ramus border and coronoid outline.
2. Muscular dissection and lateral exposure
   1. Detach the masseter muscle from its bony attachment on the lateral surface of the mandibular ramus and elevate it subperiosteally.
   2. Stop dissection once the coronoid process and its lateral surface are fully exposed.
      NOTE: Checkpoint: Ensure that the temporalis muscle remains firmly attached to the coronoid process.
3. Osteotomy and neurovascular management
   1. Identify the base of the coronoid process where it joins the mandibular ramus.
   2. Use a reciprocating saw with a fine-toothed blade (0.5 mm thickness) to perform a horizontal osteotomy at the coronoid base.
   3. Maintain shallow blade depth (≤8 mm) 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 hemostatic forceps and ligate to achieve hemostasis.
   4. Preserve the continuity of the temporalis muscle attachment during osteotomy.
   5. Identify the inferior alveolar neurovascular bundle at the osteotomy margin and clamp proximally using curved hemostatic forceps to prevent bleeding.

2. Coronoid process flap transfer and fixation

1. Flap positioning and orientation
   1. Grasp the harvested coronoid segment using Kocher or bone-holding forceps.
   2. Gently transpose the flap superiorly to the orbital floor defect site through the created tunnel.
   3. Rotate the segment in three dimensions to achieve optimal anatomical contouring relative to the defect.
      ​NOTE: Checkpoint: Confirm that the coronoid process conforms closely to the curvature of the anterior orbital floor.
2. Osseous contouring
   1. If the coronoid segment exceeds the dimensions of the orbital floor defect, use a high-speed diamond burr (5 mm tip) to trim the protruding bone edges for better adaptation.
   2. Smooth the residual edges of the maxillary bone or bone graft surrounding the defect to ensure flush contact between the graft and maxillary bone.
   3. Irrigate the area thoroughly to remove bone debris.
3. Rigid internal fixation
   1. Elevate the paranasal soft tissue flap via the existing extraoral incision to expose the residual anterior maxillary wall.
   2. Select a 1.0 mm titanium mini-plate and manually contour it to conform closely to the surface of the bone at the fixation site.
   3. Fix the plate using 5 mm length self-tapping screws (pilot holes drilled with a 1.6 mm bit).
   4. Laterally, use a 1.0 mm extended-interval L-shaped plate to bridge the coronoid graft and the zygomatic body.
   5. Confirm that the fixation provides firm immobilization of the flap.
      NOTE: Checkpoint: Ensure that the orbital contents are adequately supported by the graft, and gently palpate the globe to confirm that intraocular pressure is approximately symmetrical between both sides.

3. Soft tissue reconstruction

1. Free flap transferring
   1. Elevate and harvest the latissimus dorsi muscle free flap using the standard technique.
   2. Perform microvascular anastomosis between the flap vessels and recipient vessels in the neck region (e.g., facial artery and vein) under microscope magnification.
   3. Insert the flap to fill the soft tissue defect in the maxillary region, ensuring full coverage of the coronoid graft and titanium hardware.
   4. Suture the distal edge of the flap to surrounding soft tissue along the inferior orbital 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.
      NOTE: Checkpoint: Verify that the flap fully covers the reconstructed orbital floor and internal fixation material, and that microvascular flow is intact (confirmed by vascular patency test).
2. Alternative soft tissue management
   1. Place an iodoform gauze dressing over the intraoral soft tissue defect to serve as a temporary spacer and infection barrier.
   2. Secure the gauze in place using a tie-over dressing to prevent displacement.
   3. Reposition the labial-buccal flap over the defect area.
   4. Perform layered closure by suturing the infraorbital orbicularis oculi muscle, subcutaneous tissue, and skin sequentially with absorbable and non-absorbable sutures as appropriate.
      NOTE: Checkpoint: Confirm that the iodoform gauze is fully covered, with no exposed graft or implant, and that tension-free closure is achieved across all layers.

Results

A representative case was selected to demonstrate the clinical application of the CTPF combined with the latissimus dorsi free flap for orbital floor and maxillary reconstruction. Figure 2 shows the preoperative contrast-enhanced computed tomography evaluation of the patient. The patient presented with maxillary gingival squamous cell carcinoma invading the maxillary sinus, necessitating tumor resection that resulted in hemimaxillary and partial orbital floor...

Discussion

This article demonstrated the surgical steps of the CTPF reconstruction of the orbital floor defect. The results showed that the CTPF could be used to reconstruct medium to small defects of the orbital floor, ensuring approximate symmetry of bilateral eyeballs. Unfortunately, due to limited bone volume, the CTPF could not be used to reconstruct large defects of the orbital floor. For such patients, titanium mesh or free bone flap grafting may be better choices.

Meanwhile, because the volume an...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3-0 antibaterial vicryl absorbable suture	Johnson (Suzhou) Medical Devices Co., Ltd.	VCP1772D	For tissue suturing
DSRobot 4K-Station	Digital Vision	-	Surgery video recording
High-Frequency Electrosurgical Unit	Guangdong Baisheng Medical Equipment Co., Ltd.	OBS-350A	Precise tissue cutting and coagulation
Operating microscope	Zumax	OMS3200Pro	For microvascular anastomosis
POWERED MAXILLOFACIAL SURGERY SYSTEM	CROWN EAGLE	DSQ-3L ZD3	For osteotomy
Ultrasonic cutting and hemostasis system	Tianjin Ruiqi Surgical Instrument Company	CSUS6000	For cutting and hemostasis