It is important to study anatomy of the face to understand the pathophysiology of facial fractures and to perform facial blocks as well as airway management.
The facial skeleton consists of the frontal bone superiorly, the bones of the midface, and the mandible inferiorly.
Soft tissues described, from superficial to deep, in the following order:
• Superficial fat compartments Superficial musculo-aponeurotic system (SMAS )• Retaining ligaments
• Mimetic muscles
• Deep plane, including the deep fat compartments
Cutaneous (sensory) innervation of the face and anterosuperior part of the scalp is provided primarily by the trigeminal nerve (cranial nerve V), whereas motor innervation to the facial muscles is provided by the facial nerve (cranial nerve VII).
The skin and soft tissue of the face receive their arterial supply from branches of the facial, maxillary, and superficial temporal arteries, all are branches of the external carotid artery. The exception is a mask-like area, including the central forehead, eyelids, and upper part of the nose, which are supplied through the internal carotid system by the ophthalmic arteries.
More than three million facial injuries occur in the United States each year. Sports, accidental falls, motor vehicle accidents,
assaults, and work-related accidents account for the majority of maxillofacial injuries.
Faciomaxillary fractures are more common in adults, relatively uncommon in children and adolescents. This low incidence may reflect the underdeveloped facial skeleton and paranasal sinuses as well as the unerupted dentition which provide additional strength to the mandible and maxilla.
The nose is the most frequently injured facial structure, accounting for approximately 40% of bony injuries in facial trauma due to several factors as nasal bones and underlying cartilage are more prominent and occupy central position in the face.
Trauma to the face can cause a fracture along the weak points of the orbit. The patterns of fractures are well described: orbital-zygomatic, naso-orbito-ethmoid and internal orbital. Indeed, the thinnest and weakest area of the orbit is the floor. Typically, the fracture occurs in the posteromedial region of the orbital floor so called “blow-out” fracture.
Zygomatic fracture and dislocation not only causes cosmetic defects but also disrupts ocular and mandibular functions too. The zygomatic region is a prominent portion of the face next only to the dorsum of the nose, which predisposes this bone to various traumas. Fractures can involve any of the four articulations of zygoma which include zygomatico-maxillary complex, zygomatic complex proper,
orbitozygomatic complex. Fractures involving zygoma should be repaired as early as possible because it can cause both functional and cosmetic defects.
The mandible is the tenth most commonly injured bone in the body and the second most commonly injured bone in the face. Fractures of the mandible can be found in the symphysis, body, angle, ramus, and condyle or subcondylar areas.
Maxillary fractures are less common than mandibular fractures and are often associated with other facial fractures. Complaints such as, “My bite isn‟t right” are common as most maxillary fractures involve the dental occlusion.
René Le Fort in 1901 described a classification of maxillary fractures which is still used today, although fractures are usually of mixed types, three predominant types were described: I, II, III.
Frontal sinus injuries in both adults and children often result from blunt trauma, such as an unrestrained passenger hitting the dashboard or windshield in a motor vehicle collision. Lacerations frequently accompany frontal sinus fractures and may obscure the deeper part of the injury, and the examiner should be wary when dealing with a patient who has been struck in the forehead. These injuries should be carefully explored to ensure that any fractures are found. A CT scanning of the head is indicated for complete evaluation, since patients can have a displaced posterior table fracture without palpable anterior fractures.
The key points for diagnosis of facial fractures include detailed history taking that may reveal site and type of injury before doing investigations, followed by physical examination, careful physical examination is paramount for the diagnosis of craniofacial injury, since additional and potentially life-threatening injuries are not uncommon.
The airway is the first critical injury that may be associated with facial trauma. The patient who has sustained a maxillofacial fracture may have airway compromise due to loss of tongue support secondary to facial fractures or obstruction of the airway due to blood or debris. The patient who has sustained a significant facial fracture should be assumed to have an associated cervical spine injury. Studies have shown that approximately 10% of patients with facial fractures have injuries of the cervical spine.
The clinical examination of the face begins with a detailed examination of the area for localized tenderness, numbness, bleeding, deformity, ecchymosis, periorbital edema, otorrhea, rhinorrhea, and facial asymmetry. Facial asymmetry is often easy to examine by looking down from the head of the bed. The superior and inferior orbital rims, zygomatic arches, nose, maxilla, mandible, and both alveolar ridges should be palpated and evaluated.
Distinguishing between CSF and serous nasal secretions may be difficult. Blood from head injured patients may mix with CSF and mask the recognition of a leak. Several tests can be done to
differentiate between nasal secretions and CSF the most accurate of which is beta 2 transferrin.
All clinicians involved in trauma care should be competent in carrying out a primary survey and initiating resuscitative procedures. When managing facial injuries, this involves assessment and maintenance of the airway and control of obvious bleeding. Early consideration of vision-threatening injuries (for instance retrobulbar hemorrhage, or loss of eyelid integrity) is also important, but should not distract from the initial assessment and resuscitation. Although the aim of the primary survey is to identify and treat life-threatening problems, the early identification of a sight-threatening condition may be possible during „„D‟‟ = disability (once „„A‟‟, „„B‟‟ and „„C‟‟ have been addressed and the pupils are assessed).
A difficult airway is generally defined as a situation in which a clinician experiences difficulty with face mask ventilation, laryngoscopy, or intubation. It is important to recognize circumstances that may cause airway problems or difficult laryngoscopy.
Inadequate mask seal, excessive gas leak, or excessive resistance to the ingress or egress of gas are the main mechanisms of difficult mask ventilation. The validated indicators of difficult BMV can be easily recalled by using the mnemonic MOANS (Mask seal, Obesity/Obstruction, Age, No teeth and Stiff lungs). Difficulty with tracheal intubation is predominantly a consequence of failure to see the larynx. The most widely used classification describing view of the larynx is that described by Cormack and Lehane. An airway assessment mnemonic, LEMON (Look externally, Evaluate the 3-3-2 rule, Mallampati, Obstruction and Neck mobility), takes into account many of the anatomic factors associated with difficult intubation. Difficulty in
placing an EGD or performing cricothyrotomy are assessed from the mnemonics RODS and SHORT consequently. Laboratory and radiologic evaluation may be needed in airway assessment.
Proper management of a patient‟s airway during elective and emergency situations is of vital importance for any clinician. Because of this, the anesthesiologist should be familiar with airway aids and devices available for airway management. Regarding ventilation devices, many different types of face masks are available e.g. the Rendell-Baker face mask. An oral or a nasal airway may be used to achieve ventilation. Supraglottic airway devices also may be needed. The most important SGD is the LMA. A variety of types have been introduced into practice since the development of the original, now called the LMA Classic.
Although it is usually assumed that the „„gold standard‟‟ for airway maintenance is the tracheal tube, but inserting a tracheal tube in maxillofacial trauma patient is technically more challenging. Regarding intubation devices, Fiberoptically assisted intubation is one of the most important advances in difficult airway management since the introduction of the laryngoscope. One significant recent development in advanced airway management has been the emergence of video and optical laryngoscopy. Moreover, optical and illuminating stylets are important aids in difficult airway management.
Proper preoperative planning and preparation is the most important process for managing the difficult airway patient. At least one portable storage unit that contains specialized equipment for difficult airway management should be readily available. If the airway is predicted to be difficult to manage, a primary, preferred approach should be developed, followed by the identification of alternative approaches if the primary
approach fails or is not feasible. Emergency surgical airway access can be life saving in the cannot ventilate, cannot intubate arm of the ASA DA algorithm. A simple step-wise algorithm for the unexpected difficult pediatric airway based on an adult Difficult Airway Society (DAS) protocol has been proposed.
During airway management in trauma patient, physiologic differences should be considerd such as: rapid de-satauration during period of apnea in addition to full stomach and brain protection in TBI.
The preffered methods for airway management in faciomaxillary trauma patient include awake fiberoptic intubation if no bleeding in the field and surgical airway (cricothyroidotomy and tracheostomy) especially if a well trained physician for surgical airway is available.
Nerve blocks in the head and face are useful for the repair of lacerations and for scrubbing and debriding „roasties‟. Nerve blocks in this region are less painful to the patient than local infiltration and they do not distort the anatomy. The supraorbital nerve, the infraorbital nerve and the mental nerve all exit their foramina along a line that can be drawn 25 mm lateral to the midline of the face through the pupil and the labial angle.
General anesthesia when compared to regional anesthesia in some selected cases was found to be a safe alternative technique.
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