This article discusses the classic and contemporary management strategies for treating frontal sinus fractures. The goals of management of frontal sinus fractures are to create a safe sinus by minimizing the likelihood of early and late complications while preserving the function of the sinus and maintaining the cosmetic appearance of the upper face. The assessment and classification of patients with frontal sinus injuries, their management, and the treatment of complications are reviewed.
Key points
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Frontal sinus fractures require a significant amount of force and often present with concomitant intracranial injuries.
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Appropriate initial management helps to prevent complications including infections, cerebrospinal fluid leak, and mucocele formation.
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Management strategies for frontal sinus fractures involve the prevention of early and late complications.
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Minimally invasive approaches and endoscopic techniques are increasingly being used for the effective management of frontal sinus fractures.
Introduction
The frontal sinus is the last of the paranasal sinuses to develop, and takes on a triangular or trapezoidal shape ( Fig. 1 ). Although the functions of the paranasal sinus are not fully understood, theories include lightening the skull and cushioning the brain from blunt forces and traumatic injuries by dispersing incoming forces. The frontal sinus is generally a bilateral structure, but may be unilateral in up to 15% of patients and may be absent in 8% of the population. Lying anteriorly is the frontal table, posteriorly is the posterior table separating the brain from the sinus, and inferiorly is the orbital roof and frontal sinus outflow tract ( Fig. 2 ). The frontal sinus outflow tract is limited anteriorly by the frontal process of the maxilla forming the frontal beak. The medial wall of the outflow tract is the olfactory fossa, and the lateral wall is formed by the lamina papyracea separating the orbit from the sinus. The posterior limit is the bulla ethmoidalis, the roof being formed by the fovea ethmoidalis with the anterior ethmoidal artery coursing across it.
The frontal bones and the resultant frontal sinuses represent one of the strongest structures in the face. As a result, a significant amount of force is required to fracture them in comparison with other structures of the head and neck ( Table 1 ). Frontal sinus fractures are thus frequently associated with multiple concomitant injuries, including intracranial injuries. Frontal sinus fractures account for 5% to 15% of all facial fractures and are associated with various high-velocity and low-velocity causes such as motor vehicle accidents, gunshots, falls, and assaults.
| Location | Force Required for Fracture (lb) |
|---|---|
| Mandible | 425–925 |
| Maxilla | 140–445 |
| Zygoma | 208–475 |
| Frontal bones | 800–2200 |
| Nasal bones | 25–75 |
Injuries to the frontal sinus can be categorized into fractures that involve the anterior table, the posterior table, the outflow tract, or a combination of the 3; they can be further described as nondisplaced, displaced, or comminuted ( Fig. 3 ).
Introduction
The frontal sinus is the last of the paranasal sinuses to develop, and takes on a triangular or trapezoidal shape ( Fig. 1 ). Although the functions of the paranasal sinus are not fully understood, theories include lightening the skull and cushioning the brain from blunt forces and traumatic injuries by dispersing incoming forces. The frontal sinus is generally a bilateral structure, but may be unilateral in up to 15% of patients and may be absent in 8% of the population. Lying anteriorly is the frontal table, posteriorly is the posterior table separating the brain from the sinus, and inferiorly is the orbital roof and frontal sinus outflow tract ( Fig. 2 ). The frontal sinus outflow tract is limited anteriorly by the frontal process of the maxilla forming the frontal beak. The medial wall of the outflow tract is the olfactory fossa, and the lateral wall is formed by the lamina papyracea separating the orbit from the sinus. The posterior limit is the bulla ethmoidalis, the roof being formed by the fovea ethmoidalis with the anterior ethmoidal artery coursing across it.
The frontal bones and the resultant frontal sinuses represent one of the strongest structures in the face. As a result, a significant amount of force is required to fracture them in comparison with other structures of the head and neck ( Table 1 ). Frontal sinus fractures are thus frequently associated with multiple concomitant injuries, including intracranial injuries. Frontal sinus fractures account for 5% to 15% of all facial fractures and are associated with various high-velocity and low-velocity causes such as motor vehicle accidents, gunshots, falls, and assaults.
| Location | Force Required for Fracture (lb) |
|---|---|
| Mandible | 425–925 |
| Maxilla | 140–445 |
| Zygoma | 208–475 |
| Frontal bones | 800–2200 |
| Nasal bones | 25–75 |
Injuries to the frontal sinus can be categorized into fractures that involve the anterior table, the posterior table, the outflow tract, or a combination of the 3; they can be further described as nondisplaced, displaced, or comminuted ( Fig. 3 ).
Assessment and diagnosis
The primary goal when treating frontal sinus fractures depends on the type and severity of the fracture. Cosmetic outcomes and the correction of contour irregularities are a high priority when considering the treatment goals of isolated anterior table fractures. If the posterior table is involved, the primary treatment goal is to separate the intracranial contents from the sinus, minimizing the potential for intracranial complications such as cerebrospinal fluid (CSF) leaks, sinusitis, and intracranial infections. When fractures of the frontal sinus involve the outflow tract or nasal frontal recess, it is imperative to take into account the potential for long-term or late complications such as locally destructive or infectious lesions (eg, mucoceles and mucopyoceles).
Preoperative planning and preparation
A high index of suspicion for frontal sinus injuries is required for all patients presenting with trauma to the upper face. Signs and symptoms that may represent a fracture of the frontal bones and the paranasal sinuses include swelling of the soft tissues, contour irregularities that become more prominent as the edema resolves, hypesthesia in the first trigeminal nerve distribution, anosmia from shearing of the adjacent cribriform plate, and intracranial injuries. More extensive injuries involving both the anterior and posterior table may have leakage of CSF or exposed intracranial contents. Sensation to the forehead is supplied by branches of the first division of the trigeminal nerve through both the supraorbital and supratrochlear nerves; for this reason, sensation should be documented before operative repair. In addition, the frontal branch of the facial nerve courses from lateral to medial in the upper face, and may be damaged with significant lacerations of the upper face. The integrity of this branch should be evaluated and its function documented.
Despite the importance of documenting the physical examination findings, radiographic imaging is the gold standard for diagnosis and classifying fractures of the frontal sinus. To properly assess the fracture, a computed tomography (CT) scan with fine cuts should be obtained. Reconstruction of the images in coronal and sagittal orientations further aids in surgical planning, particularly when assessing the frontal sinus outflow tracts.
Treatment goals for frontal sinus fractures
The primary goal when treating frontal sinus fractures is to prevent the formation of early and late complications while attempting to restore form and function. Early complications have been described as problems that occur with the first 6 months of the injury and include, but are not limited to, sinusitis and meningitis. Late complications, on the other hand, can occur decades after the original traumatic event and may include findings such as bone erosion, mucoceles, mucopyoceles, and brain abscesses.
Although the perceived goals of treatment for frontal sinus injuries have remained relatively constant over the years, the specifics related to intervention and surgical treatments have evolved. For example, traditional philosophies emphasized either obliteration or cranialization when considering the management of frontal sinus fractures involving the frontal recess or outflow tracts. By contrast, current literature leans toward a more conservative approach when treating fractures of the frontal recess, with preservation of form and function.
Debate also surrounds the treatment algorithms when considering fractures of the posterior table. While most will agree that large comminuted fractures of the posterior table are often best treated with cranialization or obliteration, the treatment options for mild to moderately displaced posterior table fractures have a spectrum. Tightly adherent dura combined with deep mucosal invaginations on the posterior table of the frontal sinus increases the potential for CSF leaks and mucosal entrapment, respectively. For this reason, some argue for an obliterative procedure in the presence of any posterior table fracture, whereas others will only intervene in the presence of a persistent CSF leak or if there is significant displacement.
Procedural approach to sinus fractures
Anterior Table Fractures
The goal for treating anterior table fractures is to restore form and improve appearance. The degree of displacement is approximated by visual and palpable contour irregularities and is confirmed by radiologic imaging. When determining the severity of the contour irregularity it is important to allow the soft-tissue swelling to resolve; this process may take 7 to 10 days depending on the nature of the trauma and the severity of the injury.
For fractures that are minimally displaced and have only a slight contour irregularity, injectable fillers such as calcium hydroxyapatite or poly- l -lactic acid can be applied. For more significantly displaced anterior table fractures with moderate contour irregularities, the option of an overlay camouflage graft or open reduction with internal fixation (ORIF) may be exercised ( Fig. 4 ). Camouflage grafts with porous polyethylene and/or titanium mesh can be placed with a minimally invasive endoscopic technique or an open approach.
Fractures and contour irregularities can be visualized from a multitude of approaches such as pretrichial, upper eyelid, or supra-brow. If a laceration is present, this too can be used to visualize the fracture. When using the endoscopic approach, 2 to 3 vertical incisions approximately 1 cm in length are made just behind the hairline. The positioning of the incisions will depend on the location and sidedness of the fracture. The incision is taken down to the subperiosteal plane and an optical cavity is elevated over the forehead to the level of the brow, being sure to avoid damage to the supratrochlear and supraorbital neurovascular bundles. Once the fracture is exposed, a small external incision can be made within a relaxed skin-tension line overlying the fracture site, allowing for placement of a bone hook to assist in elevating and reducing the depressed segment. In addition, an implant can be deployed from any of the endoscopy access ports and secured with screws through small external incisions within the relaxed skin-tension lines of the forehead.
For severely displaced or comminuted fractures of the anterior table, open access to the bony fragments is often necessary. Depending on the severity and location of the fracture and characteristics of the patient such as rhytids, hairline, and expectations, a variety of external approaches are available, which include using the laceration, if available; a butterfly or “open-sky” incision placed above the brow, the direct approach whereby the incision is placed within a rhytid; a pretrichial incision; or a hemicoronal or coronal approach ( Fig. 5 ).
