Skull fractures are common injuries observed in the setting of both blunt and penetrating trauma. The frontal sinuses are located within the frontal bone, superior and medial to the orbits. The frontal sinuses begin developing around 5 to 6 years old and become fully developed between the ages of 12 to 20. They are innervated by both the supraorbital and supratrochlear nerves, which are supplied by the ophthalmic branch of the trigeminal nerve. Their blood supply comes from the supraorbital and supratrochlear arteries. The frontal sinuses consist of an anterior and posterior table (wall) and drain inferiorly and posteriorly via the frontal recess into either the middle meatus or ethmoid infundibulum depending on the attachment of the uncinate process. If the uncinate process attaches to the lamina papyracea, then the frontal sinus drains into the middle meatus via the semilunar hiatus. If the uncinate process attaches to the skull base or the middle turbinate, the sinus drains into the ethmoid infundibulum before emptying into the middle meatus. The anterior border of the frontal recess is the posterior wall of the agger nasi air cell, while the posterior wall is composed of the ethmoid bulla. The medial wall of the frontal recess is the middle turbinate, and the lateral wall is the orbit.
Frontal cranial bones have a greater thickness than the more lateral temporal bones (6.15 cm in males, 7.13 cm in females compared to 4.33 cm and 4.41 cm, respectively). As a result, these fractures require a more significant mechanism and force than other facial bone injuries, occur less frequently than other forms of skull trauma, and often present with concurrent injuries. These other concurrent injuries include frontal sinus fractures, orbital pathologies, intracranial hemorrhage, and cervical spine pathologies, to name a few. These characteristics make critical evaluation and treatment of these injuries imperative. Additionally, appropriate classification and indications for surgical repair of frontal sinus fractures remain controversial, resulting in a variety of management strategies.
The most common etiologies of frontal bone fractures in adults are motor vehicle collisions (MVCs), falls, assaults, falling objects, and penetrating trauma. One study of 164 patients reported MVCs as the most common etiology (31.7%) followed by sports accidents (28.0%), work accidents (20.1%), violence (3.7%), and domestic accidents (3.1%). Injury severity is variable and depends on the mechanism, fracture pattern, and involvement of surrounding anatomy.
In the pediatric community, MCVs were the most common etiology (25.7%), followed by sports-related injuries (16.1%), assault (14.7%), and falls (10.1%). When grouped by age range, the most common mechanism from 0 to 6.99 years old was falls (28.6%), compared with MVCs from 7 to 12.9 years old (31.9), and assaults from 13 to 18 years old.
Frontal sinus fractures account for approximately 5% to 15% of all facial bone fractures. These injuries most commonly occur in young males (92%) with a mean age of 20 to 31 years old. In pediatric patients, one report noted a male predominance (65%) and a mean age of 11.5 years old, with a majority of patients being teenagers. Parietal bone fractures are the most commonly observed skull injuries. Fractures are often linear, however depressed and basilar patterns can occur. According to Taylor et al., 2.8 million people in the United States suffer from head injuries annually, of which just over 2.1% are fatal.
History and Physical
Obtaining a thorough and comprehensive history is imperative in the initial triage and management of facial trauma patients. Due to the nature of these injuries, patients may not have the capacity to provide this information themselves, making it essential for providers to gather data from family, friends, witnesses, and first responders. Per the Advanced Trauma Life Support (ATLS) protocol, the evaluation of trauma patients begins with an assessment of the patient's airway, respiratory capacity, and circulatory status. While assessing the extent of the patient's disabilities, a thorough neurologic exam should be performed to calculate a Glasgow Coma Scale Score, assessing for cranial nerve function as well as other focal deficits and bony injury to the calvarium. The provider should inspect the entire head and neck for any lesions, abrasions, contusions, or active bleeding. It is important to assess for lacerations superficial to any sinus fractures, indicating the requirement of IV antibiotics. The anterior table of the frontal sinus should be palpated to determine if there is any bony step off, and any wounds or lacerations should be cleaned and explored. Examination of the ears can reveal battle sign, auricular hematomas, cerebrospinal fluid (CSF) otorrhea, or hemotympanum, suggesting the involvement of the skull base. A nasal examination should check for the mobility of the nasal bones, frank epistaxis, CSF rhinorrhea, septal hematomas, or active purulence. Examination of the orbit should include appropriate cranial nerve testing and inspection for raccoon eyes or retrobulbar hematoma.
After obtaining a comprehensive history and physical exam, the most important test to determine structural involvement and subsequent management is a non-contrast computed tomography scan (CT) of the head and facial bones. Various windows are available through CT imaging (osseous, soft tissue, heme windows), which make the evaluation of these and related injuries rapid and reliable. If CT is available and performed, there is no evidence showing any additional benefit from radiographs. Angiography can be considered if the provider is concerned about possible vascular involvement. Ultrasound has the ability to detect fractures with the use of the linear probe in a superficial mode; however, this should be viewed as an adjunct to the previously mentioned modalities.
Currently, there is no general consensus on the classification of frontal sinus fractures. One-third of all frontal sinus fractures include both the anterior and posterior tables of the frontal sinus, whereas two-thirds involve the anterior table only, and less than 1% involve only the posterior table. Below are some widely accepted classification systems of these fractures:
In 1997, Gonty et al. classified frontal sinus fractures into the following categories. A retrospective review of 158 patients by Gerbino et al. was performed using Gonty’s classification system and reported the percentage of patients with each type of fracture.
- Anterior table involvement (61.4%)
- Anterior and posterior table involvement (33%)
- Posterior table involvement (0.6%)
- “Through and through,” which are defined as comminuted with the involvement of the orbit, ethmoids, and nasal base (2.5%)
- Fractures involving nasofrontal duct (2.5%)
In 2014, Torre et al. presented a classification and treatment schema that is based on maximal metric dislocation and involvement of surrounding structures (nasolacrimal system, orbit, CSF leak, or surrounding bone fracture). In their study of 164 patients, they classified fracture patterns into four types with Type A being most common (38.4%) followed by type B (22.6%), type C (14%), and type D (25%).
- Type A: No displacement
- Type B: 0 to 2 mm displacement
- No concomitant injury - observation
- Concomitant injury - surgical repair
- Type C: 2 to 5 mm displacement
- No concomitant injury - observation
- Concomitant injury - surgical repair
- Type D: greater than 5 mm displacement
- Nasoorbitoethmoid (NOE) fracture
- Nasal bone fracture
- Temporal bone fracture
- Parietal bone fracture
- Pott puffy tumor
Clinical prognosis is related to the extent of the injuries sustained as well as the clinical condition of the patient. If there are many injuries, various specialists and subspecialists may be required to treat the underlying pathology. Ultimately, isolated frontal sinus fractures have a good prognosis, regardless of whether or not the nasofrontal outflow tract or posterior table is involved. Advancements in surgical technique and equipment have improved the preservation of the frontal sinuses as well as the patients’ quality of life.
Complications of frontal sinus fractures are typically divided into two categories based on chronicity: acute (less than 6 weeks) or chronic (greater than 6 weeks), but complications overlapping these timeframes can happen. These include but are not limited to:
- Frontal sinusitis
- Cerebrospinal fluid leak
- Poor aesthetic outcome
- Brain abscess
- Chronic frontal headaches
- Extrusion of graft material
- Intracranial hemorrhage
- Paresthesia of the supraorbital, infraorbital, and/or supratrochlear nerves
- Hypoesthesia or paresthesia of the ophthalmic nerve (V1) or maxillary nerves (V2)
- Facial deformity
The list of possible consultations below varies per the injury to the frontal sinus itself as well as it's surrounding structures.
- Trauma surgery
- Oral and maxillofacial surgery
- Facial plastic surgery
- Neurology - if associated traumatic brain injury (TBI) is present
- Intensivist - depending on injury severity and clinical condition
- Physical medicine and rehabilitation (PM&R) - depending on concurrent injuries and disease progression
Deterrence and Patient Education
Frontal sinus fractures are often caused by unanticipated trauma, so it is difficult to provide definitive guidelines on how to deter these situations. The authors recommend obeying safety precautions with vehicles and other machinery, which can help to reduce the severity of these injuries. Avoiding precarious situations can help to prevent assaults or falls.
Pearls and Other Issues
- The most common etiologies of frontal bone fracture are motor vehicle collisions (MVCs), falls, assaults, falling objects, and penetrating trauma. These injuries most commonly occur in young males (92%) with a mean age of 20 to 31 years old.
- Trauma patients, especially those who have sustained cranial and facial injuries, must be critically evaluated based on ATLS protocols. It is important to avoid distraction by obvious or deforming injuries and focus on establishing or maintaining a definitive airway, preserving respiratory status, and supporting circulatory volume. After the initial stabilization, a thorough history and physical needs to be performed. The most important test to determine structural involvement and to plan management is a non-contrast computed tomography scan (CT) of the head and facial bones. If a frontal sinus fracture is observed on CT, this indicates significant trauma, and it is imperative to search for corresponding injuries.
- Multiple classification systems have been proposed since 1999, but there is currently no universally agreed-upon system to follow. These protocols can guide treatment based on classification.
- Based on concurrent injuries, surgical intervention can vary immensely. Options can include frontal sinus ablation/obliteration, cranialization, open reduction internal fixation (ORIF), minimally invasive techniques, and conservative management with observation.
- Complications vary per the extent of the injury but can include frontal sinusitis, meningitis, CSF leak, mucocele, poor aesthetic outcome, brain abscess, frontal headaches, ophthalmoplegia, and/or local paresthesia.
- A multidisciplinary team will be necessary for the diagnosis and treatment of frontal sinus fractures depending on the local structures affected.
Enhancing Healthcare Team Outcomes
Frontal sinus fractures could require an interprofessional team depending on the extent of the injury. The emergency response team will be necessary to identify any life-threatening injuries and stabilize the patient upon presentation. Surgical reconstruction will need to be carried out by the proper surgical specialists, which could vary depending on any associated injuries and surgeon availability. One or multiple board-certified surgeons may be needed to treat these patients, which could include an otolaryngologist, facial trauma surgeon, oral and maxillofacial surgeon, facial plastic surgeon, neurosurgeon, and/or ophthalmologist. The operating room (OR) staff, including surgical technicians and circulating nurses, will be imperative to keep the OR moving smoothly and improve surgical outcomes. An intensive care unit or critical care team made up of physicians, advanced practice providers, nurses, and other staff may be needed to manage the patient medically either pre- or postoperatively.