FRONTAL BONE FRACTURE

FRONTAL BONE FRACTURE IN
ORAL & MAXILLOFACIAL SURGERY
DETAILED

1. FRONTAL BONE FRACTURE PRESENTED BY – Dr.ANKITA RAJ (MDS Reader) Oral & Maxillofacial Surgery Department Rama Dental College, Kanpur

2. INTRODUCTION Fractures of the frontal bone occur among 2 to 15% of patients with facial fractures. Its fracture can cause devastating complications because of its close proximity to the brain, eyes, and nose . Most victims are male (66–91%) and young (usually 20–30 yr of age, range 6–72 yr) Injuries are sustained in motor vehicle or motorcycle collisions (44–85%) The frontal bone is like half of a shallow, irregular cap forming the forehead or frons . It has three parts and contains two cavities, THE FRONTAL SINUSES.

3. EMBRYOLOGY The frontal bone is an intramembranous bone that develops from 2 paired structures that begin to ossify at the 8th or 9 th week in utero . The ossification begins in the frontal processes of the squamous regions, progresses to the orbital and squamous regions, and reaches the frontal and temporal regions by the 12th week. The metopic suture in the midline closes during the second year of life. The forehead is displaced anteriorly by sutural growth, inner table resorption , and outer table deposition

4. The frontal sinus is Absent at birth The frontal sinuses are derived from the frontal recess portion of the middle meatus or occasionally from an air cell of the ethmoid infundibulum Initial pneumatization begins during the 4 th month in utero . Secondary pneumatization begins at the age of 6 months to 2 years and develops laterally and vertically. The sinuses are radiologically evident at 5 to 6 years of age. Most pneumatization is completed by the time the child is 12 to 16 years old but it continues until the age of 40 .

5. SURGICAL ANATOMY From the nasion the bone extends approximately 12.5 cm superiorly,8.0 cm laterally, and 5.5 cm posteriorly . Two frontal tuberosities are noted lateral to the midline and superior to the supraorbital rim. The thickest area of the bone is the supraorbital rim from the frontozygomatic process to the nasal bones.

6. The supraorbital foramen are located at the most superior portion of the orbital rim. The supratrochlear foramen is located medial to the supraorbital foramen or notch and lateral to the nasal bones. A spine or concavity exists on the frontal bone along the medial anterior orbital roof; the trochlea of the superior oblique muscle is attached to this spine

7. FRONTAL SINUSES are paired air filled asymmetric triangular cavity lined by pseudo stratified ciliated columnar epithelium found within the frontal bones and are separated by a frontal septum. The dimensions are- Height 32mm Width 26mm Depth 17mm Surface area 720 mm2 The outer and inner bony walls are referred to as inner and outer tables . The anterior wall of the sinus is stronger than the posterior wall, but it also has low resistance to either low-energy or high- energy impact. The posterior wall of the sinus is thinner and weaker and separates the sinus from the dural covering of the brain in the ACF

8. The sinus floor consists of membranous bone and is the thinnest of the sinus boundaries. Importantly, the floor of the frontal sinus is on average 3.1 mm below the nasion (i.e., the frontonasal suture). Drainage of the frontal sinus is variable. A true FND exists in only 15% of the population, varying from a few millimeters to 1 cm in length. In the remaining 85%, the frontal sinus drains directly into the anterosuperior portion of the middle meatus via an ostium without a true duct or occasionally by a communication through the ethmoids .

9. FUNCTIONS OF FRONTAL SINUS Production and storage of mucus Resonator for voice Humidification and warming of inhaled air Accesory area of olfaction. Conservation of heat from the nasal fossae Definition of facial contour Surge tank to dampen the pressure differential that develops during inspiration.

10. DIAGNOSIS The diagnosis of the frontal sinus fracture based on the proper history and physical examination of the patient which includes inspection and palpation of the affected area. The detailed history includes the following points: 1. Information about events 2. Visual difficulties 3. Numbness 4. Pain 5. Rhinorrhea 6. Sense of smell 7. Previous history of nasal or sinus disease surgery.

11. Clinical Features 1. Forehead laceration 2. Forehead pain 3. Swelling 4. Frontal bone depression 5. Periorbital ecchymosis 6. CSF rhinorrhea

12. Today computed tomography (CT) scans are the gold standard for imaging these fractures

13. CLASSIFICATIONS 1) Stanley’s Classification of Frontal Sinus Fracture • Type I: Anterior Table Fracture –– Isolated to anterior table –– Accompanied by supraorbital rim fracture –– Accompanied by naso-ethmoid complex fracture • Type II: Anterior and Posterior Table Fractures –– It is a linear fracture either on transverse direction or in vertical direction • Type III: Comminuted Fractures –– Isolated to both tables –– Accompanied by naso-ethmoid complex fracture

14. 2) Gonty Et al. Classification of Frontal Sinus Fracture • Type I: Anterior Table Fracture –– Isolated to anterior table –– Accompanied by supraorbital rim fracture –– Accompanied by naso-ethmoid complex fracture • Type II: Anterior and Posterior Table Fractures –– A linear fracture either on transverse direction or in vertical direction –– Comminuted fracture either isolated to both tables or accompanied by naso-ethmoid complex fracture • Type III: Posterior Table Fracture • Type IV: Through and Through Frontal Sinus Fracture

15. MANAGEMENT

16. REFERENCES Maxillofacial trauma by Peter Ward Booth Petersons Principles of Oral and Maxillofacial Surgery 2 Vol. set by Michael Miloro , G. E. Ghali , Peter E. Larsen Fonseca Volume 3 –Trauma Grays anatomy – 41 ST Edition McMinn and Abrahams' Clinical Atlas of Human Anatomy

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