Residency · Residency · Otolaryngology

Frontal Sinus Fractures

Introduction

Frontal sinus fractures account for approximately 5-12% of all facial fractures and result from high-impact trauma to the forehead. The frontal sinus occupies a unique position at the interface of the cranium and facial skeleton, making these injuries potentially dangerous due to the risk of intracranial complications. Management decisions hinge on which anatomic components are involved: the anterior table, posterior table, and nasofrontal outflow tract (NFOT).

Anatomy

Frontal Sinus Structure

Paired, irregularly shaped sinuses separated by an intersinus septum. Anterior table: thick cortical bone providing contour to the forehead. Posterior table: thin bone forming the anterior wall of the anterior cranial fossa; lined by dura. Nasofrontal outflow tract (NFOT): drainage pathway connecting the sinus to the middle meatus; may be a true duct (nasofrontal duct) or a recess. The NFOT is the narrowest portion and is most vulnerable to obstruction from fracture, edema, or scarring.

Important Relationships

Dura is tightly adherent to the posterior table. Anterior ethmoidal artery courses along the skull base near the posterior table. Pneumatization is variable; approximately 5% of adults have aplastic or hypoplastic frontal sinuses.

Mechanism of Injury

High-velocity blunt trauma: motor vehicle accidents, assault, falls, sports injuries. Force required to fracture the anterior table: approximately 800-1600 Newtons. Force required to fracture the posterior table: approximately 800-2000 Newtons (despite being thinner, it is supported by intracranial contents).

Classification

By Anatomic Involvement

Anterior table only: most common pattern. Posterior table involvement: indicates potential dural injury. NFOT involvement: risk of mucocele formation if not addressed. Combined anterior and posterior table with NFOT involvement: most complex.

By Displacement

Non-displaced: <1 table width of displacement. Displaced: significant step-off or comminution. Comminuted: multiple fracture fragments.

Associated Injuries

CSF leak: indicates dural tear (posterior table fracture). Pneumocephalus: air in the intracranial cavity. Orbital fractures: commonly associated. Naso-orbito-ethmoid (NOE) fractures: suggest NFOT involvement. Intracranial injuries: epidural hematoma, brain contusion.

Evaluation

Clinical Assessment

Forehead laceration or contusion overlying the frontal sinus. Frontal depression: palpable step-off. Periorbital ecchymosis: raccoon eyes. CSF rhinorrhea: clear nasal drainage; test with beta-2 transferrin. Subcutaneous emphysema. Full neurologic examination; GCS assessment.

Imaging

CT face and head with thin cuts (1 mm): axial, coronal, and sagittal reformats. Evaluate: anterior table integrity, posterior table displacement, NFOT patency, pneumocephalus, intracranial hemorrhage. CT angiography if trajectory suggests vascular injury.

Management Algorithm

Anterior Table Fractures

Non-displaced: observation, serial clinical and radiographic follow-up. Displaced (cosmetically significant): open reduction internal fixation (ORIF) via coronal approach or endoscopic-assisted reduction. Comminuted with NFOT involvement: ORIF + NFOT evaluation and possible obliteration.

Posterior Table Fractures

Non-displaced, no CSF leak: observation with close follow-up. Displaced or CSF leak present: surgical exploration. Minimal displacement: craniotomy, dural repair, posterior table reconstruction. Significant comminution: cranialization (removal of posterior table, stripping of sinus mucosa, dural repair, allowing brain to fill the sinus space).

NFOT Obstruction

Obstruction of the outflow tract risks mucocele formation (may present years later). If NFOT is patent: no intervention needed. If NFOT is obstructed: sinus obliteration (removal of all mucosa, filling with fat, bone, or hydroxyapatite) or cranialization.

Surgical Techniques

ORIF of Anterior Table

Coronal incision with subperiosteal dissection. Reduction of fracture fragments with low-profile titanium plates and screws. Preserve or reconstruct periosteum over the repair.

Sinus Obliteration

Complete removal of all sinus mucosa (meticulous stripping with diamond burr). Obliterate with abdominal fat, bone, hydroxyapatite, or other biocompatible material. Plugging of the NFOT with bone or fascia.

Cranialization

Removal of the posterior table, Complete stripping of all mucosa. Pericranial flap rotated to cover the floor of the anterior cranial fossa. Dural repair (primary or with graft), Brain expansion fills the former sinus space.

Complications

Mucocele/mucopyocele: from retained mucosa; may present years to decades later with frontal swelling, orbital displacement, or intracranial extension. CSF leak: persistent leak may require surgical repair. Meningitis and brain abscess: from contaminated sinus communicating with intracranial space. Frontal contour deformity: from malreduction or bone resorption. Chronic frontal sinusitis: from NFOT obstruction without obliteration. Osteomyelitis: Pott puffy tumor (subperiosteal abscess of the frontal bone).

Key Clinical Pearls

The management of frontal sinus fractures is dictated by involvement of three structures: anterior table, posterior table, and NFOT. CSF rhinorrhea with a frontal sinus fracture indicates posterior table and dural injury — requires surgical intervention if persistent. Mucocele is the most feared long-term complication; meticulous mucosal stripping is essential during obliteration or cranialization. Non-displaced anterior table fractures without NFOT involvement can be safely observed. Long-term follow-up (annual imaging for 5+ years) is recommended after obliteration or cranialization to monitor for mucocele.

References

1. Bell RB, Dierks EJ, Brar P, et al. A protocol for the management of frontal sinus fractures emphasizing sinus preservation. J Oral Maxillofac Surg. 2007;65(5):825-839.
2. Rodriguez ED, Stanwix MG, Nam AJ, et al. Twenty-six-year experience treating frontal sinus fractures: a novel algorithm based on anatomical fracture pattern and failure of conventional techniques. Plast Reconstr Surg. 2008;122(6):1850-1866.
3. Metzinger SE, Guerra AB, Garcia RE. Frontal sinus fractures: management guidelines. Facial Plast Surg. 2005;21(3):199-206.
4. Xie C, Mehendale N, Barrett D, et al. 30-year review of frontal sinus fractures: shifting paradigms. Laryngoscope. 2008;118(7):1110-1115.

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