Etiologies

Although trauma is a leading cause of death in pediatric age groups, pediatric craniomaxillofacial (CMF) trauma accounts for only about 15% of all CMF trauma, and that number includes teenagers. Younger children probably only account for about 5% of CMF trauma, and maxillofacial injuries in this age group are frequently associated with skull fractures and concomitant neurologic injuries. Unique to the infant are facial fractures caused by traumatic delivery. In the newborn, this facial trauma can be owing to forceps being used to bring the baby down through the birth canal. This can result in neonatal injury, including fractures of the skull and facial skeleton, as well as soft tissue trauma, such as injury to the facial nerve. These injuries are less common today than previously owing to the increased use of Cesarean section when a difficult delivery is anticipated.

In the edentulous and deciduous dentition stage, skull fractures are much more common than maxillofacial fractures because the cranium is more prominent than the face. Falls are the most common cause, but abuse/neglect must remain a cause for which providers are vigilant, particularly with repeated injuries or sketchy histories. In the nonambulatory child, being dropped or rolling off a bed or sofa are likely mechanisms of injury often leading to lateral as well as frontal skull and skull base injuries. Small children also suffer injuries owing to motor vehicle accidents. The early ambulating child is more likely to fall forward, striking the chin and forehead on the ground. The most common soft tissue injuries are owing to dog bites that can be associated with fractures. However, primarily soft tissue injuries are beyond the scope of this article.

As the child grows, sports, motor vehicle, and bicycle accidents and fighting become more common causes. As children approach their teens, they are more likely to be involved in trauma associated with more adult behavior. Teenagers are more likely to engage in risk-taking adventures and substance abuse that might lead to an increased risk of traumatic injury. Falls from heights and vehicular trauma become more frequent during the teen years. Like adults, common causes include recreational accidents, particularly with off-road vehicles like all-terrain vehicles and bicycles. Other sports-related injuries are more common, and interpersonal and industrial traumatic events increase in frequency. Because the management of post puberty teenage trauma is similar to adult trauma, the rest of this article focuses primarily on prepubescent and pubescent patients.

Comparative and Developmental Anatomy

The pediatric age group includes everyone from birth to maturity, which is typically considered to occur around the age of 16 years, although some consider it to continue to age 18. During this time, the pediatric facial skeleton goes through progressive development and major changes. Some of these include :

• •
  

  Change in the size ratio of the cranium to the face;

  
  
• •
  

  Change in the ratio of facial soft tissue to bone, dental eruption → shedding → eruption; and

  
  
• •
  

  Pneumatization of the sinuses.

The softness of the infant bone results in more incomplete (greenstick) fractures in infancy, which changes as the child grows and the solidity of the bone increases. The growth centers are more cellular and therefore even softer and more susceptible to injury.

Skull–Face Ratio

At birth, the cranium is much larger relative to the facial skeleton than it is at maturity. In the small child, the relative proportion of the craniofacial skeleton represented by the face, particularly the lower face, is still much less. As the child grows, the lower face lengthens and widens, developing to represent a greater proportion of the overall craniofacial skeleton. Similarly, the mid face, although larger than the mandible in early childhood, still represents a much smaller area relative to the skull. As the child develops into adulthood, the relative growth of the face exceeds that of the skull, and the relative size of the facial skeleton increases ( Fig. 1 ). Thus, in infancy, cranial injuries are far more common in proportion to those of the facial skeleton, and as children grow and mature, nasal, mid facial, and mandibular fractures become more common. As the facial skeleton comes to represent a larger proportion of the craniofacial skeleton, it becomes more exposed to potential injuries. Therefore, mandible fractures are less frequent, owing to the small area of the mandible relative to the face and skull in the infant. However, the small ambulating child is likely to trip and fall forward, striking the chin and fracturing the mandible even if it is still relatively small. The nose also becomes more prominent with maturation, and the small, diminutive noses of infancy are typically displaced by the larger, adult nasal anatomy. In adulthood, the nose is the most frequently fractured facial bone, followed by the mandible.

Cranial to facial ratio comparison in a neonate, toddler, and adult.

( Courtesy of Columbia University Medical Center, New York, NY; with permission.)

Small Sinuses

The paranasal sinuses are small in infancy, and the frontal sinuses in fact do not even begin to develop until the preteen years. The paranasal sinuses develop throughout childhood. The newborn has small ethmoid sinuses and poorly aerated sphenoid sinuses, as well as typically small maxillary sinuses. The frontal sinuses generally do not even begin to form until 9 to 12 years of age. By the teenage years, the maxillary, ethmoid, and sphenoid sinuses tend to be well developed, with the frontals reaching full growth around age 16 to 18 years ( Fig. 2 ). Sinus development corresponds with the enlarging size of the maxillofacial skeleton. As the face develops, it occupies a greater percentage of the head relative to the cranial vault. This is believed to contribute to the greater relative incidence of facial fractures compared with skull fractures as maturity is reached.

Development of paranasal sinuses, birth to adult.

( Courtesy of Dr Russell Faust, Franklin, MI.)

Brain and Ocular Injuries

The facial skeleton is smaller, making the cranial vault more exposed to injury. The sinuses are theorized to provide protection to the cranium, brain and eyes, among other structures, functioning as a “crumple zone” that can lead to facial fractures that might absorb energy upon impact and thereby minimize the damage to more vital structures. The less collapsible facial skeleton may lead to an increased number of cranial and neurologic injuries in infancy and early childhood.

Tooth Buds

As children grow and develop, their facial structures grow and develop. This includes the teeth, which start out as germinal centers within the bones of the maxilla and mandible and occupy most of the bone in the lower maxilla and anterior mandible in early childhood ( Fig. 3 ). As we develop, these form teeth that gradually erupt through the alveolar bone and through the gingiva. There are ultimately 20 deciduous teeth that generally erupt between ages 1 and 6 years, and these are then pushed out by the developing permanent dentition between the ages of 6 and 14 years. The final 4 posterior molars develop later and become the so-called wisdom teeth. There are ultimately 32 teeth in the full adult dentition. These are numbered 1 to 32, counting from the maxillary right posterior molar to the left, 1 to 16, then continuing around from the mandibular left posterior as number 17 to the right posterior molar, which is number 32. The deciduous teeth are designated in the same order with letters, A–J in the maxilla and K–T in the mandible.

Skulls with outer cortex removed showing deciduous and permanent dentition in early childhood.

( Courtesy of McLoughlin Dental Care, Milwaukie, OR; with permission.)

The presence of deciduous and mixed dentition creates unique difficulties for the CMF surgeon, because the conical deciduous teeth do not hold wires and arch bars well. Also, as their roots resorb they are easily extracted with wires. The presence of the unerupted permanent dentition in the bone makes it difficult to properly position plates for repair of fractures. Once the permanent teeth have fully erupted, they provide excellent fixation points for wires that can be used to attach arch bars for stabilization of the occlusal relationships.

As noted, tooth buds are present in the bone of the maxillae and the mandible, making them prone to injury when facial fractures occur. If a tooth bud is injured, it is less likely to develop into a fully formed normal tooth, and eruption may be less likely. Tooth buds can be injured by trauma, particularly fractures, and they can be injured by the surgeon during the repair.

Softer Bone

The developing bone is less calcified and therefore less hard than fully mature calcified bone. The interosseous sutures are also softer and more flexible. This flexibility makes complete through and through fractures less likely, also contributing to the lower frequency of fractures needing repair in the pediatric age group. These incomplete fractures, known as ‘greenstick’ fractures are more often seen in children. This term ‘greenstick’ refers to the greater resilience seen in living (green) branches of a tree, compared with the easy-to-break, dried out dead branches. Greenstick fractures are generally incomplete like bending of the bone, so that little or no reduction of the fracture might be needed. One cortex is fractured, and the fragments are held together by the second cortex of the bone. However, growth centers like the condylar region are relatively hypercellular and therefore softer, leading to greater susceptibility to burst-type fractures. Such fractures are rarely seen in adults.

More Soft Tissue

Children have more soft tissue both subcutaneously and in localized fat pads (baby fat) covering the maxillofacial skeleton than normal adults, which results in a greater likelihood of soft tissue injury. As might be expected, owing to greater padding of the skeleton, this leads to fewer fractures. (Of course, the softer bone is less likely to break, adding to this effect.) However, severe soft tissue injuries are still common, and the facial nerve is in a more superficial anatomic position in the infant and young child.

Fracture Patterns

As in adults, any part of the pediatric CMF skeleton can be fractured, but certain fractures are more common. The difference in fracture patterns seen in children relative to adults is owing to a combination of the noted factors, namely, the mechanisms of injury, the softness and compliance of the bone, the presence of tooth buds, the smaller size of the paranasal sinuses, the relatively small size of the face compared with the skull, and the greater amount of facial soft tissue. Because of these differences between adult and pediatric anatomy and the differences in likely mechanisms of injury (low-energy short falls vs high-energy sports and motor vehicle injuries), the fracture mechanisms and patterns are different as well. All of these factors affect the exposure of the facial skeletal bones to trauma as well as their response to impact.

Skull fractures are more common than facial fractures, but orbital roof and other skull base fractures without calvarial fractures are also more likely. Upper facial fractures are typically associated with cranial vault fractures and are, therefore, often associated with more serious intracranial injuries.

Midface fractures are uncommon until the mixed dentition stage, becoming more common in puberty; when they do occur before mixed dentition, they do not typically follow Le Fort fracture patterns because of tooth buds and underdeveloped sinuses. Orbital floor fractures become more common as the maxillary sinus pneumatizes.

Nasal fractures are probably the most common facial fracture in children, but many are probably missed owing to decreased nasal prominence in the child or not studied owing to noncentralized and/or minimal management.

The mandible is the next most commonly fractured facial bone with symphyseal and condylar fractures leading. The frequency of forward falling, the softness of the condylar growth center, and underdevelopment of the menton are likely contributors. Dental and dentoalveolar fractures start to become more common as the teeth erupt. Children who are victims of high-energy injuries can suffer pan facial fractures, as can adults.

Etiologies

Although trauma is a leading cause of death in pediatric age groups, pediatric craniomaxillofacial (CMF) trauma accounts for only about 15% of all CMF trauma, and that number includes teenagers. Younger children probably only account for about 5% of CMF trauma, and maxillofacial injuries in this age group are frequently associated with skull fractures and concomitant neurologic injuries. Unique to the infant are facial fractures caused by traumatic delivery. In the newborn, this facial trauma can be owing to forceps being used to bring the baby down through the birth canal. This can result in neonatal injury, including fractures of the skull and facial skeleton, as well as soft tissue trauma, such as injury to the facial nerve. These injuries are less common today than previously owing to the increased use of Cesarean section when a difficult delivery is anticipated.

In the edentulous and deciduous dentition stage, skull fractures are much more common than maxillofacial fractures because the cranium is more prominent than the face. Falls are the most common cause, but abuse/neglect must remain a cause for which providers are vigilant, particularly with repeated injuries or sketchy histories. In the nonambulatory child, being dropped or rolling off a bed or sofa are likely mechanisms of injury often leading to lateral as well as frontal skull and skull base injuries. Small children also suffer injuries owing to motor vehicle accidents. The early ambulating child is more likely to fall forward, striking the chin and forehead on the ground. The most common soft tissue injuries are owing to dog bites that can be associated with fractures. However, primarily soft tissue injuries are beyond the scope of this article.

As the child grows, sports, motor vehicle, and bicycle accidents and fighting become more common causes. As children approach their teens, they are more likely to be involved in trauma associated with more adult behavior. Teenagers are more likely to engage in risk-taking adventures and substance abuse that might lead to an increased risk of traumatic injury. Falls from heights and vehicular trauma become more frequent during the teen years. Like adults, common causes include recreational accidents, particularly with off-road vehicles like all-terrain vehicles and bicycles. Other sports-related injuries are more common, and interpersonal and industrial traumatic events increase in frequency. Because the management of post puberty teenage trauma is similar to adult trauma, the rest of this article focuses primarily on prepubescent and pubescent patients.

Comparative and Developmental Anatomy

The pediatric age group includes everyone from birth to maturity, which is typically considered to occur around the age of 16 years, although some consider it to continue to age 18. During this time, the pediatric facial skeleton goes through progressive development and major changes. Some of these include :

• •
  

  Change in the size ratio of the cranium to the face;

  
  
• •
  

  Change in the ratio of facial soft tissue to bone, dental eruption → shedding → eruption; and

  
  
• •
  

  Pneumatization of the sinuses.

The softness of the infant bone results in more incomplete (greenstick) fractures in infancy, which changes as the child grows and the solidity of the bone increases. The growth centers are more cellular and therefore even softer and more susceptible to injury.

Skull–Face Ratio

At birth, the cranium is much larger relative to the facial skeleton than it is at maturity. In the small child, the relative proportion of the craniofacial skeleton represented by the face, particularly the lower face, is still much less. As the child grows, the lower face lengthens and widens, developing to represent a greater proportion of the overall craniofacial skeleton. Similarly, the mid face, although larger than the mandible in early childhood, still represents a much smaller area relative to the skull. As the child develops into adulthood, the relative growth of the face exceeds that of the skull, and the relative size of the facial skeleton increases ( Fig. 1 ). Thus, in infancy, cranial injuries are far more common in proportion to those of the facial skeleton, and as children grow and mature, nasal, mid facial, and mandibular fractures become more common. As the facial skeleton comes to represent a larger proportion of the craniofacial skeleton, it becomes more exposed to potential injuries. Therefore, mandible fractures are less frequent, owing to the small area of the mandible relative to the face and skull in the infant. However, the small ambulating child is likely to trip and fall forward, striking the chin and fracturing the mandible even if it is still relatively small. The nose also becomes more prominent with maturation, and the small, diminutive noses of infancy are typically displaced by the larger, adult nasal anatomy. In adulthood, the nose is the most frequently fractured facial bone, followed by the mandible.

Cranial to facial ratio comparison in a neonate, toddler, and adult.

( Courtesy of Columbia University Medical Center, New York, NY; with permission.)

Small Sinuses

The paranasal sinuses are small in infancy, and the frontal sinuses in fact do not even begin to develop until the preteen years. The paranasal sinuses develop throughout childhood. The newborn has small ethmoid sinuses and poorly aerated sphenoid sinuses, as well as typically small maxillary sinuses. The frontal sinuses generally do not even begin to form until 9 to 12 years of age. By the teenage years, the maxillary, ethmoid, and sphenoid sinuses tend to be well developed, with the frontals reaching full growth around age 16 to 18 years ( Fig. 2 ). Sinus development corresponds with the enlarging size of the maxillofacial skeleton. As the face develops, it occupies a greater percentage of the head relative to the cranial vault. This is believed to contribute to the greater relative incidence of facial fractures compared with skull fractures as maturity is reached.

Development of paranasal sinuses, birth to adult.

( Courtesy of Dr Russell Faust, Franklin, MI.)

Brain and Ocular Injuries

The facial skeleton is smaller, making the cranial vault more exposed to injury. The sinuses are theorized to provide protection to the cranium, brain and eyes, among other structures, functioning as a “crumple zone” that can lead to facial fractures that might absorb energy upon impact and thereby minimize the damage to more vital structures. The less collapsible facial skeleton may lead to an increased number of cranial and neurologic injuries in infancy and early childhood.

Tooth Buds

As children grow and develop, their facial structures grow and develop. This includes the teeth, which start out as germinal centers within the bones of the maxilla and mandible and occupy most of the bone in the lower maxilla and anterior mandible in early childhood ( Fig. 3 ). As we develop, these form teeth that gradually erupt through the alveolar bone and through the gingiva. There are ultimately 20 deciduous teeth that generally erupt between ages 1 and 6 years, and these are then pushed out by the developing permanent dentition between the ages of 6 and 14 years. The final 4 posterior molars develop later and become the so-called wisdom teeth. There are ultimately 32 teeth in the full adult dentition. These are numbered 1 to 32, counting from the maxillary right posterior molar to the left, 1 to 16, then continuing around from the mandibular left posterior as number 17 to the right posterior molar, which is number 32. The deciduous teeth are designated in the same order with letters, A–J in the maxilla and K–T in the mandible.

Skulls with outer cortex removed showing deciduous and permanent dentition in early childhood.

( Courtesy of McLoughlin Dental Care, Milwaukie, OR; with permission.)

The presence of deciduous and mixed dentition creates unique difficulties for the CMF surgeon, because the conical deciduous teeth do not hold wires and arch bars well. Also, as their roots resorb they are easily extracted with wires. The presence of the unerupted permanent dentition in the bone makes it difficult to properly position plates for repair of fractures. Once the permanent teeth have fully erupted, they provide excellent fixation points for wires that can be used to attach arch bars for stabilization of the occlusal relationships.

As noted, tooth buds are present in the bone of the maxillae and the mandible, making them prone to injury when facial fractures occur. If a tooth bud is injured, it is less likely to develop into a fully formed normal tooth, and eruption may be less likely. Tooth buds can be injured by trauma, particularly fractures, and they can be injured by the surgeon during the repair.

Softer Bone

The developing bone is less calcified and therefore less hard than fully mature calcified bone. The interosseous sutures are also softer and more flexible. This flexibility makes complete through and through fractures less likely, also contributing to the lower frequency of fractures needing repair in the pediatric age group. These incomplete fractures, known as ‘greenstick’ fractures are more often seen in children. This term ‘greenstick’ refers to the greater resilience seen in living (green) branches of a tree, compared with the easy-to-break, dried out dead branches. Greenstick fractures are generally incomplete like bending of the bone, so that little or no reduction of the fracture might be needed. One cortex is fractured, and the fragments are held together by the second cortex of the bone. However, growth centers like the condylar region are relatively hypercellular and therefore softer, leading to greater susceptibility to burst-type fractures. Such fractures are rarely seen in adults.

More Soft Tissue

Children have more soft tissue both subcutaneously and in localized fat pads (baby fat) covering the maxillofacial skeleton than normal adults, which results in a greater likelihood of soft tissue injury. As might be expected, owing to greater padding of the skeleton, this leads to fewer fractures. (Of course, the softer bone is less likely to break, adding to this effect.) However, severe soft tissue injuries are still common, and the facial nerve is in a more superficial anatomic position in the infant and young child.

Fracture Patterns

As in adults, any part of the pediatric CMF skeleton can be fractured, but certain fractures are more common. The difference in fracture patterns seen in children relative to adults is owing to a combination of the noted factors, namely, the mechanisms of injury, the softness and compliance of the bone, the presence of tooth buds, the smaller size of the paranasal sinuses, the relatively small size of the face compared with the skull, and the greater amount of facial soft tissue. Because of these differences between adult and pediatric anatomy and the differences in likely mechanisms of injury (low-energy short falls vs high-energy sports and motor vehicle injuries), the fracture mechanisms and patterns are different as well. All of these factors affect the exposure of the facial skeletal bones to trauma as well as their response to impact.

Skull fractures are more common than facial fractures, but orbital roof and other skull base fractures without calvarial fractures are also more likely. Upper facial fractures are typically associated with cranial vault fractures and are, therefore, often associated with more serious intracranial injuries.

Midface fractures are uncommon until the mixed dentition stage, becoming more common in puberty; when they do occur before mixed dentition, they do not typically follow Le Fort fracture patterns because of tooth buds and underdeveloped sinuses. Orbital floor fractures become more common as the maxillary sinus pneumatizes.

Nasal fractures are probably the most common facial fracture in children, but many are probably missed owing to decreased nasal prominence in the child or not studied owing to noncentralized and/or minimal management.

The mandible is the next most commonly fractured facial bone with symphyseal and condylar fractures leading. The frequency of forward falling, the softness of the condylar growth center, and underdevelopment of the menton are likely contributors. Dental and dentoalveolar fractures start to become more common as the teeth erupt. Children who are victims of high-energy injuries can suffer pan facial fractures, as can adults.