# Orbital Fractures and Surgical Repair

## Introduction

Orbital fractures are common sequelae of facial trauma and can result in functional and cosmetic deformity. The orbit is composed of seven bones, with the **floor** (maxillary bone) and **medial wall** (lamina papyracea) being the thinnest and most frequently fractured. Timely evaluation and appropriate surgical intervention are essential to prevent permanent diplopia and enophthalmos.

## Anatomy of the Orbital Walls

**Roof**: frontal bone (thick anteriorly, thins at orbital plate) **Floor**: maxillary bone (0.5 mm thick); contains the **infraorbital nerve** and canal. **Medial wall**: lamina papyracea of the ethmoid (0.2-0.4 mm, thinnest wall) **Lateral wall**: greater wing of sphenoid and zygoma (thickest wall) **Orbital rim**: dense cortical bone providing structural support.

## Classification of Orbital Fractures

### Blowout Fractures

**Pure blowout**: fracture of an orbital wall without rim involvement. Most common locations: floor > medial wall > combined floor and medial wall. Mechanism: **hydraulic theory** (globe transmits force to walls) and **buckling theory** (direct force on orbital rim causes wall buckling)

### Other Fracture Types

**Blow-in fractures**: wall fragments displaced into the orbit (associated with roof fractures) **Tripod (zygomaticomaxillary complex) fractures**: involve lateral wall, floor, and infraorbital rim. **Le Fort fractures**: types II and III involve the orbit. **Trapdoor fractures**: linear fracture with periosteal hinge; common in children (white-eyed blowout); tissue entrapment with minimal radiographic findings. **Naso-orbito-ethmoidal (NOE) fractures**: involve medial wall, nasal bones, and medial canthal tendon.

![CT scan (coronal view) demonstrating a left orbital floor blowout fracture with herniation of orbital contents into the maxillary sinus](/images/ophthalmology/orbital-floor-blowout-ct.jpg)

## Clinical Evaluation

### History

Mechanism and timing of injury. Diplopia (especially in upgaze), pain, numbness, visual change. History of epistaxis (do not blow nose -- risk of orbital emphysema)

### Examination

**Visual acuity** and **pupillary exam** -- rule out associated globe injury. **Forced duction testing** -- differentiate entrapment from muscle edema/hemorrhage. **Hertel exophthalmometry** -- document enophthalmos (may be masked initially by edema) **Infraorbital nerve sensation** -- hypesthesia in V2 distribution. **Extraocular motility** -- restriction (especially upgaze in floor fractures, lateral gaze in medial wall fractures) **Oculocardiac reflex** -- bradycardia, nausea, and syncope suggest tissue entrapment (especially in pediatric trapdoor fractures)

### Imaging

**CT orbit and face** (thin-cut axial and coronal): gold standard. Evaluate fracture location, size, degree of herniation, muscle position. Look for associated injuries: globe rupture, retrobulbar hemorrhage, intracranial injury.

## Indications for Surgical Repair

### Urgent (Within 24-48 Hours)

**Pediatric trapdoor fracture** with muscle entrapment and oculocardiac reflex. Non-resolving oculocardiac reflex with tissue incarceration. Early enophthalmos with large fracture.

### Semi-Urgent (Within 1-2 Weeks)

Persistent diplopia in functional gaze positions with positive forced ductions. CT evidence of muscle or periorbital tissue entrapment. Large floor fracture (>50% of floor or defect >2 cm) predicting late enophthalmos. Significant enophthalmos (>2 mm)

### Observation

Minimal diplopia resolving with conservative management. Small fractures without entrapment or significant herniation. Isolated medial wall fractures with minimal symptoms.

## Surgical Techniques

### Approaches

**Transconjunctival** (preseptal or retroseptal) -- preferred; lower rate of lid retraction and ectropion. **Subciliary** -- good exposure but higher risk of lower lid malposition. **Transantral (Caldwell-Luc)** -- rarely used; endoscopic-assisted approach gaining popularity. **Transcaruncular** -- for medial wall fractures.

### Implant Materials

**Titanium mesh** -- strong, thin, easily contoured; risk of implant palpability. **Porous polyethylene (Medpor)** -- tissue integration; difficult to remove if infected. **Resorbable plates** (PDS, PLLA) -- avoid permanent implant; limited structural support. **Autologous bone** (split calvarial, iliac crest) -- gold standard for large defects but donor site morbidity. **Nylon foil (Supramid)** -- thin, flexible; used for small defects.

| Implant Material | Advantage | Disadvantage | Best Use |
|---|---|---|---|
| Titanium mesh | Strong; easily contoured; radiopaque | Palpability; thermal conductivity | Medium-large defects |
| Porous polyethylene (Medpor) | Tissue integration; stable | Difficult removal if infected | Medium-large defects |
| Resorbable plates (PDS, PLLA) | No permanent implant | Limited structural support | Small defects; pediatric |
| Autologous bone | Biocompatible; gold standard | Donor site morbidity; resorption | Large defects |
| Nylon foil (Supramid) | Thin; flexible; inexpensive | Limited strength | Small defects |

![Intraoperative photograph showing titanium mesh implant placement for orbital floor reconstruction](/images/ophthalmology/orbital-floor-titanium-mesh.jpg)

## Complications

Persistent or new-onset diplopia. Lower lid retraction or ectropion (especially with subciliary approach) Infraorbital nerve injury. Implant infection, extrusion, or migration. Retrobulbar hemorrhage (rare, vision-threatening) Residual enophthalmos.

![3D CT reconstruction showing a right zygomaticomaxillary complex fracture](/images/ophthalmology/zmc-fracture-3d-ct.jpg)

## Key Clinical Pearls

Pediatric trapdoor fractures are surgical emergencies -- muscle necrosis occurs within hours. The "white-eyed blowout" in children can have minimal external signs but severe entrapment. Never instruct a patient with orbital fracture to blow their nose. Enophthalmos may be masked by acute edema; reassess at 1-2 weeks. Forced duction testing under anesthesia is essential to confirm entrapment before repair.

## References

1. Burnstine MA. Clinical recommendations for repair of orbital facial fractures. Curr Opin Ophthalmol. 2003;14(5):236-240.
2. Jordan DR, et al. Intervention within days for some orbital floor fractures: the white-eyed blowout. Ophthalmic Plast Reconstr Surg. 1998;14(6):379-390.
3. Boyette JR, et al. Management of orbital fractures: challenges and solutions. Clin Ophthalmol. 2015;9:2127-2137.
4. American Academy of Ophthalmology. Orbit, Eyelids, and Lacrimal System. BCSC Section 7. 2023-2024.