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Facial Fracture Management Handbook - Pathophysiologic considerations

last modified on: Thu, 04/26/2018 - 13:49

Facial Fracture Management Handbook

by Dr. Gerry Funk   return to: Facial Fracture Management Handbook

 

see also: Introduction, Bibliography, and other Sections.

Pathophysiologic considerations in bony facial trauma

Facial trauma is predominantly an occurrence in the young male. Eighty to 90% of facial trauma victims are male, the majority are between the ages of 15 to 30 years. The most frequent etiology of severe facial trauma is motor vehicle accident related. If nasal fractures are included the most common etiology overall is interpersonal conflict. A lesser number of facial fractures are the result of sports injuries and industrial accidents as well as miscellaneous injuries (1,2).

There are a number of different types of facial fractures. For a particular patient one or more fractures may be present which defy exact categorization, and it is useful to group the different facial fractures into classes based primarily on the bones involved and the architecture of the fracture. With some degree of overlap, each fracture type presents with its own particular set of pathophysiologic concerns, work up considerations and definitive management. For example, management of frontal sinus fractures requires special attention to intracranial injury and prevention of mucocele formation in the sinus at a later date. In mandible fractures occlusion is a major concern.

Severe trauma to the facial bones may impact on nearly every physiologic function occurring in the head, including: mentation, vision, lacrimation, hearing, the sense of smell, respiration via a patent airway, mastication and swallowing, drainage of the sinuses, spinal canal integrity and cranial nerve function. Facial trauma may also have a profound effect on facial aesthetics and thereby exert an influence on the psychological well being of the trauma victim. Challenges in the comprehensive management of facial trauma are not simply how to best put the bones back together, but to understand and manage all of the problems that have occurred because the bones are broken. Later sections of this manual will present the management of each particular type of fracture in some detail, but first a review of the major pathophysiologic concerns involved in facial trauma is important as a foundation on which to add that knowledge.

Airway Management

In the acute management of multitrauma victims with possible life threatening thoracic, cardiovascular, abdominal or intracranial injuries the definitive repair of facial fractures is appropriately given a lesser priority. However, the presence of facial fractures may significantly affect the most important acute intervention of all, securing an airway. Therefore, all physicians involved in the emergency management of trauma patients must be aware of the potential for airway difficulties in the facial trauma patient and how to safely manage them. Thompson, et al reported on 117 LeFort fractures, 26.5% of patients presented with airway obstruction, decreased respiration or both requiring endotracheal intubation or tracheostomy to secure an airway (5).

As well as recognizing the potential for airway compromise in the facial trauma patient the managing physician must be aware of the special considerations involved in establishing an airway in these patients.

Oral endotracheal intubation cannot be performed without cervical spine manipulation and should not be attempted prior to clearance of the cervical spine. Orotracheal intubation of patients with mandible and midfacial fractures may also be difficult if significant edema or bleeding is present in the oral cavity or pharynx. Frequently these patients are combative and attempted oral intubation is a dangerous struggle with a tenuous airway. While occasionally necessary in extreme situations oral intubation of the awake facial trauma patient is not the best choice to secure the airway.

Severe skull base trauma as may be present in LeFort III fractures may result in tears of the nasopharyngeal mucosa and musculature, blind nasotracheal intubation in these cases may result in worsening pharyngeal tears, exacerbation of bleeding, possible intracranial penetration of the endotracheal tube and unfortunately the airway may not be secured. In most facial fracture cases nasotracheal intubation is a reasonable option, however it should be done over a flexible bronchoscope with visualization of the path of the endotracheal tube. Adequate suction must be available to deal with blood in the oral cavity and pharynx. Nasal intubation over a bronchoscope can be done with no motion of the cervical spine and therefore is reasonable if the cervical spine has not been formally cleared. For all but the most skilled operator, intubation of a thrashing, intoxicated trauma victim over a bronchoscope, may be quite difficult. If time permits, calming the patient down and obtaining good anesthesia and vasoconstriction of the nasal passages may prevent a dangerous situation from developing if several failed attempts result in brisk bleeding from the nasal passages.

There are many situations in which a tracheostomy or cricothyrotomy is the most rapid and safe means of securing an airway. If there is evidence of laryngotracheal trauma and the integrity of the laryngeal and subglottic mucosa is in question, endotracheal intubation may be extremely dangerous or further injure the larynx. In some cases of massive facial trauma with significant bleeding, an oral or nasal intubation may simply not be possible. In many cases of multiple trauma the patient will eventually require a tracheostomy and it is reasonable to simply secure the airway with a controlled tracheostomy at the time of admission. If possible, it is best to perform the tracheostomy in the operating room under local anesthesia with the patient awake. If a cricothyrotomy is done as an emergency intervention because time would not permit a formal tracheostomy, it should be converted to a tracheostomy within 24 hours to prevent the possibility of cricoid cartilage infection.

Neurological Injury

Impact forces sufficient to fracture facial bones, particularly if delivered to the upper third of the face, should always be assumed to have caused a cervical spine and intracranial injury until proven otherwise. In a large series of severe frontal sinus fractures 75% were accompanied by a loss of consciousness; prolonged loss of consciousness (coma) was present in 25%. In this same series 31% of patients presented with CSF leaking from the wound or nose and an additional 13% had brain tissue visible in the wound (3). Mid-facial fractures of the LeFort type are also associated with CSF leak, presumably via disruption of the skull base in the cribriform plate area. CSF rhinorrhea following LeFort fractures has been reported to occur in from 24% to 66% of cases. The natural history of CSF rhinorrhea following mid-facial fractures is different than the CSF leaks resulting from severe trauma to the cranial vault, as for example in severe frontal sinus fractures. Appreciating this difference is crucial to the management in both cases. CSF rhinorrhea following mid-facial fractures will frequently resolve spontaneously following fracture reduction and a period of bed rest. CSF leak resulting from gross damage to the anterior cranial fossa, with or without pneumocephalus is unlikely to stop spontaneously and the surgical plan should include dural repair (4).

Varying degrees of closed head trauma are also frequently associated with severe bony facial trauma. Neurosurgical consultation and CT scanning of the brain should be performed if the history suggests a loss of consciousness lasting any more than several minutes. Because facial trauma is frequently associated with intoxication, a reliable history, mental status exam and neurologic exam may be difficult, requiring the use of a brain CT to exclude intracranial trauma in the uncooperative patient.

As stated above a cervical spine injury must be assumed to exist in all facial fracture patients until it has been excluded with high quality cervical spine films read by an attending radiologist. The emergency department resident holding them up to the overhead light will not do. If satisfactory C-spine films cannot be obtained the patient must remain in a hard collar. Occasionally a CT scan of the neck will be required to clear the spine.

Associated Ocular Injury

In a large series of facial fracture patients, some degree of ocular injury was sustained in 67%. Of those patients with eye injuries 18% had serious injuries and 3% were blinded (6). The subject of ocular injury associated with facial trauma is quite broad. The goal here is to present fundamental knowledge required to diagnose various ocular injuries and define the role of the nonophthalmologist in the management of facial trauma patients with ocular injuries. Given the high incidence of associated ocular injuries with facial fractures the physician managing facial trauma should always have a very low threshold for calling an ophthalmologist to evaluate the patient. In any case with positive findings on ocular exam or a complaint of an abnormality of vision of any kind, involving an ophthalmologist is mandatory. A detailed description of the ocular exam is included in the physical exam section below.

Severe lid laceration, in particular any lid laceration medial to the lacrimal punctae requires the attention of an ophthalmologist. Corneal or scleral lacerations, ocular foreign bodies and injury to the lacrimal drainage apparatus need to be ruled out in these cases.

Penetrating trauma as well as extensive fractures involving the orbital walls may result in rupture of the globe, this is an ophthalmologic emergency. The eye will often appear flat and small and may be soft. No further ocular exam should be performed. The eye should be covered with a protective shield and an ophthalmologist called. In some cases of globe rupture usable vision may be restored if a small scleral rupture is repaired soon after the injury.

Decreased extraocular movements (EOM) following facial trauma may be due to several etiologies. Small decreases in EOM following facial trauma are most frequently the result of edema and pain during attempted extreme lateral, up or down gaze. If an orbital blowout fracture is suspected, forced duction exam will rule in or out mechanical entrapment of intraorbital structures, most frequently the inferior rectus muscle or orbital fat surrounding it. Abnormal EOM may also indicate injuries of cranial nerves III, IV or VI. In the case of a neurologic etiology forced duction exam will be negative. Complete ophthalmoplegia (inability to move the globe) associated

with facial fractures suggests a severe trauma to the orbital apex and may indicate compression of the superior orbital fissure. If this is accompanied by ptosis and anesthesia in the distribution of cranial nerve V1 a superior orbital fissure syndrome exists. In many cases this may be reversible with surgical disimpaction of bone fragments compressing the superior orbital fissure. These patients are also frequently treated with high dose steroids to decrease edema (7,8). Prompt consultation with an ophthalmologist is essential in facial fracture cases presenting with an abnormal EOM exam.

Traumatic injuries of the optic nerve can be roughly broken into three classes: 1) compressive, 2) ischemic contusion and 3) crush or transection. These injuries most frequently present with a significant subjective and objective decrease in vision. Frequently the optic nerve has sustained a combination of the above types of injuries. As well as decreased vision one hallmark of an acute optic nerve injury is an afferent pupillary defect (APD) indicating decreased or absent conduction of afferent signals via the optic nerve to the brain. An APD may be complete with no pupillary response to light or partial indicating some remaining afferent conduction. A partial APD is also known as the Gunn pupil sign or positive swinging flashlight test which is described in the exam section (9).

Compressive injuries may be due to anything compressing the optic nerve, this may include bone fragments, hematoma or edema fluid. This type of optic nerve injury may be reversible with removal of the compressing entity surgically or pharmacologically with steroids and mannitol, and it therefore demands prompt evaluation and treatment. One characteristic of compressive injuries of the optic nerve, either in the orbit or optic nerve canal, is that they may not occur immediately following the trauma and therefore seeking a history of a progressive or delayed loss of vision following the trauma is essential.

It is well recognized that blunt trauma to the lateral, upper orbital rim can cause immediate blindness even in the absence of obvious fractures (10,11). The mechanism is felt to be an ischemic contusion of the optic nerve within the optic canal due to the disruption of small arterioles within the optic canal resulting from a transient deformation of the bone of the optic canal. In many cases actual fractures are not present, however this type of injury may also accompany orbital fractures or even facial fractures which are not adjacent to the affected eye. The management of an ischemic contusion injury to the optic nerve is controversial. One of the problems in clearly defining a management protocol is that a pure ischemic contusion injury is unlikely and some element of reversible compression may be present. Documenting the time and manner of onset of the visual loss is crucial, a progressive onset or even a short delay of onset following the trauma suggests a much better prognosis for visual return than blindness occurring immediately following the trauma. High dose corticosteroids have shown benefit in some of these cases and should be instituted immediately. Surgical decompression may play a role in selected cases and prompt consultation with a physician capable of performing optic nerve decompression should be made (11,12).

Optic nerve transection or severe crush injury presents a grave prognosis for any return of useful vision. In most such cases severe trauma to the orbital apex is evident. Optic nerve transection is more frequently associated with penetrating trauma than blunt trauma. In the case of a severe crush injury to the optic nerve with preservation of nerve continuity, steroids may be considered, however the return of useful vision would be very unlikely.

The role of the nonophthalmologist in cases of suspected optic neuropathy is to quickly make the diagnosis, begin the work up to identify a potentially treatable optic neuropathy and in many cases to institute steroid treatment while awaiting consultation with the ophthalmologist. Once a visual loss and positive APD have been identified the next crucial diagnostic intervention is a high resolution bone window CT scan of the orbits (8). The CT will allow the identification of compressing bone fragments or hematoma; if there has been a severe optic nerve crush injury this too will be evident. The CT is also useful if no fractures are seen. In that event it is clear that the etiology is likely to be an ischemic contusion injury as described above. The reader is referred to the selected references for a more detailed discussion of this interesting topic.

Dental Considerations and Occlusion

Both LeFort and Mandible fractures have the potential to change existing occlusion, therefore restoration of functional occlusion is an important consideration in many bony facial trauma cases. Even quite small post-traumatic occlusal disharmonies may result in chewing difficulty, chronic temporomandibular pain as well as annoying discomfort for the patient. In order to understand dental and occlusal management and be able to communicate with dental colleagues effectively regarding facial trauma patients, an appreciation of some fundamental dental concepts and definitions is needed. This section describes the dental and occlusal considerations central to the management of bony facial trauma patients.

Human dentition is composed of two sets of teeth, the primary or deciduous dentition and the permanent dentition. Between the ages of approximately 6 and 12 years both primary and permanent dentition exist. This is the age of mixed dentition. We will later see that patients with mixed dentition and facial fractures require special consideration with regard to the method of fracture fixation. The primary dentition consists of 20 teeth and a universal lettering scheme is applied to them.

Fortunately, the overwhelming majority of facial fractures occur in patients beyond the age of 12 - 13 years and therefore we will concern ourselves primarily with the permanent dentition. There are 32 permanent teeth each with a name and given a number according to the universal numbering system.

"Zahnschema OK 1" and "Zahnschema UK 1" by Partynia - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons -

It is important that the universal numbering system be used in the description and charting of injuries involving the dentition. Correct terminology regarding the location of dental injuries is also necessary. Figure 3 defines the terms mesial, distal, buccal, labial and lingual as they refer to dentition.

The mesiodistal relationship of the mandibular and maxillary occlusal arches is classically grouped using the Angle classification shown here.

TYPE I
"Class1type2" and " Type2by Dr. Vipin C. P. - http://en.wikipedia.org/wiki/File:Class1type2.jpg. Via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Class1type2.jpg#mediaviewer/File:Class1type2.jpg

 - "Class II" by Dr. Vipin C. P. / Challiyan at en.wikipedia - Transferred from en.wikipedia. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Class_II.jpg#mediaviewer/File:Class_II.jpg
                                                                            

The three classes include: Class I (neutroclusion, 73%), Class II (distoclusion, 24%) and Class III (mesioclusion, 3%). The Angle classification defines skeletal occlusal relationships resulting from size differences between the mandible and maxilla. This classification is based on the relationship of the maxillary and mandibular first molars. Because in the "normal" situation the maxillary central incisor is twice as wide as the mandibular central incisor, the mesiobuccal cusp of the maxillary first molar should rest in the buccal groove of the mandibular first molar in Class I occlusion. Mandibular retrognathism (Class II) occurs when the mesiobuccal cusp of the maxillary first molar rests mesial to the buccal groove of the mandibular first molar and mandibular prognathism (Class III) occurs when the mesiobuccal cusp of the maxillary first molar rests distal to the buccal groove of the mandibular first molar. Knowledge of the preinjury occlusive class for patients with severe facial trauma may be very important in establishing a functional occlusal relationship in the operating room. Preinjury photos and dental records may provide this valuable information.

There are several other occlusive relationships which should be familiar. Centric occlusion is the position of maximal dental contact between the maxilla and mandible. An anterior open bite occurs when the molars contact prematurely leaving a space between the upper and lower mesial dentition. This is frequently seen following LeFort fractures and results from the downward displacement of the posterior maxilla. Normally the maxillary dentition rests approximately one half tooth width buccal to the mandibular dentition. If the buccal cusps of the maxillary dentition rest lingual to the buccal cusps of the mandibular dentition then a state of crossbite exists. Overjet refers to the horizontal relationship and overbite refers to the vertical relationship of the incisors (13).

Because of their position and rigid anchorage to the mandible and maxilla the teeth themselves are prone to trauma. Teeth may be traumatically impacted, luxated, avulsed or fractured. The important anatomic elements of the dental gingival complex are shown here.

"Tooth Section" by User:Indolences - Based on Image:ToothSection.jpg. Licensed under Creative Commons Attribution-Share Alike 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Tooth_Section.svg#mediaviewer/File:Tooth_Section.svg

A detailed discussion of dental trauma is beyond the scope of this manual. However, it is important that you be aware of basic dental trauma management because in most hospitals a general dentist will not be available for consultation. The overall health, dental hygiene and associated injuries of the patient frequently dictate decisions made concerning the acute management of dental injury associated with facial fractures.

In most cases impacted or luxated teeth can be gently repositioned and secured to an arch bar in anticipation of future definitive dental attention. As a general rule, an attempt should be made at reimplantation of most avulsed teeth. The tooth should be gently cleaned with saline, do not scrape the fragments of periodontal membrane from it. The avulsed tooth is repositioned in the socket and secured to an arch bar. If a tooth is fractured without pulp exposure no immediate care is needed. For a fracture that has exposed the pulp, involvement of a dentist as soon as possible may permit salvage of the tooth. Small pulp exposures may acutely require only coverage with calcium hydroxide. Endodontic therapy will usually be needed for larger pulp exposures resulting from fractures of the crown and root or root alone. If pulp is exposed and dental care will need to be put off, the patient should be on antibiotics. In this situation the exposed pulp should not be manipulated and the defect will serve as a drain for the contaminated pulp cavity, definitive dental attention should be sought as soon as possible.

The question of removing teeth which are in a fracture line is controversial, again the overall health and dental hygiene of the patient play a role in the decision making. Common wisdom in the past dictated that teeth in fracture lines be removed. This position has been challenged with several series demonstrating excellent results with selected retention of teeth in mandibular fracture lines (14). As a guideline, the following are situations in which the tooth or fragment within a fracture line should be extracted: 1) gross mobility of the tooth within the bone, 2) presence of existing periapical infection, 3) root fracture, 4) presence of nonrestorable carious lesions and 5) the tooth interferes with fracture reduction (15).

Sinus Drainage

Problems of sinus drainage in association with facial fractures are confined largely to the frontal sinus. Trauma to the nasofrontal duct area may result in obstruction of mucus flow through the nasofrontal ducts to the nose. This situation then results in the collection of mucus and formation of a mucocele, which is an expansile cyst capable of destroying bone and prone to infection of its contents. Donald has maintained that the cuboidal mucosa of the frontal sinus is more apt to form mucoceles following trauma than mucosa in other areas of the sinonasal tract and he therefore takes an aggressive approach to the obliteration or cranialization of the frontal sinus in cases where there is any possibility of nasofrontal duct obstruction (3,16,17). The formation of a mucocele and its clinical presentation may take 10 to 20 years. Because of this, patients who have had frontal sinus or nasoethmoid fractures need to be warned that some type of lifelong follow up is advisable.

Facial Aesthetics

(related to bony trauma)

In the management of facial trauma our underlying mission is to restore function and form. We have looked at some of the basics of function and it is appropriate that we briefly discuss the restoration of facial form. The most important underlying foundation in the restoration of facial contour in cases of bony facial trauma is anatomic reduction of bone fragments whenever possible. Unfortunately, the midfacial, orbital and nasoethmoid bones are frequently comminuted and perfect replacement of all fragments is often not possible. Several guides exist which allow approximation of the position of the more obvious elements of facial form. The anterior projection of the malar eminences, can be gauged by reconstruction of the arch of the zygoma. Midfacial height is restored by placing the patient into intermaxillary fixation, which establishes the preinjury plane of occlusion, using the ramus and condyle of the mandible to "set" the location of the occlusal plane and thereby the midfacial height. If the mandibular ramus or condyle have been fractured they must be anatomically reduced before this can be done. One of the most difficult post-traumatic deformities to correct is telecanthus (medial canthi too far apart). There are several methods used to approximate the normal intercanthal distance and a number of techniques used to repair traumatic telecanthus, these will be discussed in detail in the section on nasoethmoid fractures. Of course meticulous attention to soft tissue injuries of the face plays a crucial role in the restoration of facial aesthetics.