OVERVIEW
Frontal Sinus fractures in the adult make up 5-15% of all facial fractures, about 9/100,000 adults.
A force of 800-2200lbs of force is required to cause a frontal sinus fracture.
Frontal sinus is usually a paired structure measuring 3.5×2.5×1.5cm (variable).
Pneumatization occurs late in the 2nd trimester and can be seen radiographically at about 6yrs old.
ANATOMY
Arterial blood supply: Supraorbital artery, Anterior ethmoidal artery
Venous supply: Supraorbital vein, Anterior ethmoidal vein, diploic veins of Breschet, Superior sagittal sinuses
Cell Lining: Pseudostratified ciliated columnar respiratory epithelium
Draining: Mucin cleared by ciliary flow through the nasofrontal ducts. Nasofrontal ducts located at medial aspect of floor and drains into middle meatus of nose.
EVALUATION:
Signs of fracture: History of trauma to forehead with or without depression in forehead, laceration, periorbital ecchymosis, contusions, hematoma, supraorbital/supratrochlear nerve distribution numbness, subconjunctival hematoma, subcutaneous air crepitus, and cerebrospinal fluid (CSF) rhinorrhea.
CSF leak: Clear fluid from nose (may be red and mixed with blood). Double Halo or Ring test – Nasal drainage drop is placed on cotton sheet or filter paper. If a red central dot (blood) is surrounded by a clear halo (CSF) suspect a CSF leak. This test is not 100% accurate. If suspected gather samples and test for chloride, glucose, and ß2-transferrin. CSF shows high chloride, low glucose, and ß2-transferrin is a protein marker found only in CSF.
Axial and coronal CT views are the best. +/- contrast (contrast to r/o intracranial bleeding)
CLASSIFICATION:
Anterior table only
+/- nasofrontal duct involvement
Posterior table only
Combination of the above.
Non displaced or displaced. Displaced fractures are classified when the bones are displaced more than the width of the tables. They can be classified as right, left, or bilateral.
SURGICAL CONSIDERATIONS:
Layers of the scalp acronym: “SCALP”
S – Skin
C – SubCutaneous layer
A – Muscularaponeurosis (Galea is aponeurosis only – 0.5mm thick) -> Extends laterally as temporoparietal fascia/superficial temporal fascia/suprazygomatic SMAS (superficial musculoaponeurotic system) -> conects to SMAS of face
L – Loose connective tissue/Subaponeurotic layer/subgaleal fascia
P – Pericranium
COMPLICATIONS:
Acute: wound infection, sinus infection (osteomyelitis, infection of new contents from obliteration, retrograde intracranial), meningitis, CSF leaks
Chronic: Mucocele, mucopyocele (purulent mucocele), cosmetic deformity (from osteomyelytic defect), chronic headaches, neuro defects (supraorbital numbness)