Facial trauma

2 Facial trauma


Soft tissue injuries







History


Our understanding of the management of maxillofacial injuries is the result of thousands of years of accumulated knowledge and experience by those who came before us. The ancient texts of the Sumerians (5000 bc), and the Egyptians (3500 bc) offer specific advice for the management of a variety of maxillofacial injuries. In particular, they discuss that soft tissue injuries may harbor other deeper injuries to bone or brain and that the surgeon should explore the wound with their finger to feel for these injuries.1,2 The renaissance texts from Europe and Mexico write about the importance of treating life-threatening wounds and not ignoring the restoration of cosmetic appearance: “the wounds of the face … have to be cured with extreme care because the face is a man’s honor.”3 They also understood that infection was uncommon in facial wounds but very common in extremity wounds. Because of this, the usual recommendation for placement of a cotton wick to drain the wounds was not a part of facial wound closure. They also understood that sutures should be removed early to prevent suture marks on the face.


Today we have a better understanding of the science behind the empiric knowledge of the past, but the basic tenets described hundreds and thousands of years ago still stand: look for underlying injuries, cleanse the wound, minimal debridement, and careful anatomic alignment and suture technique.



Basic science


The etiology of facial soft tissue trauma varies considerably depending upon age, sex, and geographic location. Many facial soft tissue injuries are relatively minor and are treated by the emergency department without a referral to a specialist. There are little data regarding the etiology of facial trauma that is subsequently referred to a specialist, but it is weighted towards more significant traumas such as road crashes and assaults. The location of facial soft tissue trauma tends to occur in certain areas of the head depending on the causative mechanism. When taking all etiologies of facial trauma into account, the distribution is concentrated in a “T-shaped” area that includes the forehead, nose, lips and chin. The lateral brows and occiput also have localized frequency increases.4 These areas are more prone to injury because they primarily overlie bony prominences that are at risk from any blow to the face, whether that be an assault, fall, or accident (Fig. 2.1).




Global considerations


Almost all soft tissue injuries of the head involve the skin in some manner. The skin of the head shows more variety than any other area of the body in terms of thickness, elasticity, mobility and texture. Consider the profound differences between the thick, inelastic, hair-bearing skin of the scalp compared with the thin, elastic, mobile skin of the eyelids. Consider also, the transitions from external skin of the face to the orbital, nasal, and oral linings. Significant differences in the structure of the facial skin in different areas require different methods for the repair and reconstruction. In addition, many facial structures are layered with an outer skin layer, central cartilaginous support or muscular layer, and an inner mucosal lining or second skin layer (e.g., eyelids, nose, lips, ears).


Anyone who has suffered a cut lip or scalp knows first hand that the face is well perfused. The dense interconnected network of collateral vessels in the face means that injured tissue with seemingly insufficient blood will in fact survive, whereas the same injury would result in tissue necrosis in another area of the body. The implication is that more (and potentially invaluable) tissue can be salvaged. This is especially important for areas with little or no excess tissue to sacrifice, or areas that are notoriously difficult to recreate later, for example, the oral commissure. When repairing the face, conservative debridement is usually preferable. If a segment of tissue appears only marginally viable, but is indispensable from a reconstructive standpoint, it should be loosely approximated and re-examined in 24–48 h. At that time, a line of demarcation will usually delineate what will survive and what will die. Nonviable tissue may then be debrided during a second look procedure.


Because the face is so well perfused its ability to resist infection is better than other areas of the body. Human bites to the hand treated without antibiotics have approximately a 47% risk of infection,5 whereas if we inadvertently bite our cheeks, lips or tongue we almost never develop an infection. The lower risk of infection in the face has practical applications for management of facial soft tissue injuries. Many a medical student has been told that any wound that has been open for 6 hours cannot be closed primarily. This belief is based on tradition rather that good science. While there is no doubt that the longer a wound is open the more likely it is to become contaminated, there is no magical time cut-off for primary closure.6 Because the face carries such profound cosmetic importance, the small increased risk of infection associated with delayed closure of a wound will be trumped by improved cosmesis associated with primary closure. This author recommends closure of facial wounds at the earliest time possible that will not interfere with the management of other more serious injuries, but do not let time deter you from obtaining primary closure.



Diagnosis and patient presentation


Our attention is often captured by the obvious external manifestations of craniofacial soft tissue injuries because of the alteration in appearance, however, we should not be distracted from a methodical examination for other injuries. Seemly straightforward wounds often harbor injuries to the facial skeleton, teeth, nerves, parotid duct, eyes, or brain.




Systematic evaluation of the head and neck


Initial observation, inspection and palpation will generally provide most of the information a practitioner will need. Ideally, the examination should be done with adequate anesthesia and sterile technique, as well as good lighting, irrigation, and suction as needed.


Inspection of the skin will reveal abrasions, traumatic tattoos, simple or “clean” lacerations, complex or contusion type lacerations, bites, avulsions, or burns. A careful check for facial symmetry may reveal underlying bone injury. One should systematically palpate the skull, orbital rims, zygomatic arches, maxilla, and mandible feeling for asymmetry, bony step-off, crepitus or other evidence of underlying facial fracture. Palpation within the wound may identify palpable fractures or foreign bodies. Sensation of the face should be tested with a light touch, and motor activity of the facial nerve should be tested before the administration of local anesthetics. If local anesthetics are administered it is important that the time, location, and composition of the anesthetic is well documented in the chart so that subsequent examinations will not be confounded.








Neck examination


The first priority when evaluating a soft tissue injury to the neck is evaluation of the airway. You should be concerned about the patient’s airway if they have garbled speech, dysphonia, hoarseness, persistent oropharyngeal bleeding, or if they appear agitated or struggling for air.7 Once the airway is secured, and the exam shows no compromise, the soft tissue injury should be examined with adequate light and suction to rule out penetration deep to the platysma. If the soft tissue injury penetrates through the platysma then the trauma surgeons must be consulted to evaluate a penetrating neck injury.





Treatment and surgical techniques



Anesthesia for treatment


Good anesthesia is often necessary for patient comfort and the cooperation that is needed to complete a comprehensive evaluation. Most soft tissue injuries of the head and neck can be managed with simple infiltration or regional anesthesia blocks. Patients who are uncooperative because of age, intoxication, or head injury may require general anesthesia. Patients with extensive injuries requiring more involved reconstruction, or who would require potentially toxic doses of local anesthetics will likewise require general anesthesia.


With the exception of cocaine, all of the local anesthetics cause some degree of vasodilatation. Epinephrine is commonly added to anesthetic solutions to counteract this effect, to cause vasoconstriction, to decrease bleeding, and to slow absorption and increase duration of action. Epinephrine should not be use in patients with pheochromocytoma, hyperthyroidism, severe hypertension, or severe peripheral vascular disease or patients taking propranolol. Every medical student has learned that epinephrine should never be injected in the “finger, toes, penis, nose, or ears.” This admonition is based on anecdotal reports or simple assumptions. There is very little data to support the notion, and plastic surgeons routinely use epinephrine in the face including the ears and nose with very rare complications. Unfortunately, from a medico-legal standpoint it is probably best to avoid epinephrine in the above-mentioned areas unless clinical judgment determines that the very small risks of epinephrine are outweighed by the benefits.



Topical


Topical anesthetics are well established for the treatment of children with superficial facial wounds and to decrease the pain of injection. The most widely used topical agent is a 5% eutectic mixture of local anesthetics (EMLA) containing lidocaine and prilocaine.8,9 EMLA has been shown to provide adequate anesthesia for split thickness skin grafting,10 and minor surgical procedures such as excisional biopsy and electrosurgery.11 Successful use of EMLA requires 60–90 min of application for adequate anesthesia. The most common mistake leading to failure is not allowing sufficient time for diffusion and anesthesia. Some areas such as the face with a thinner stratum corneum may have onset of anesthesia more quickly.




Facial field block


Field block of the face can provide anesthesia of a larger area with less discomfort and fewer needle sticks for the patient. A field block may provide better patient tolerance of multiple painful injections of local anesthetic when a local infiltration of an epinephrine containing solution is needed. Field blocks are more challenging to perform, and take time to take effect. Impatient surgeons often fail to wait a sufficient amount of time (at least 10–15 min) for most blocks to take effect.




Lateral nose, upper lip, upper teeth, lower eyelid, most of medial cheek (infraorbital nerve)


Anatomy: The infraorbital nerve exits the infraorbital foramen at a point that is medial of the mid-pupillary line and 6–10 mm below the inferior orbital rim.


Method: Identify the infraorbital foramen along the inferior orbital rim by palpation. An intraoral approach is better tolerated and less painful (Fig. 2.5). Place the long finger of the nondominant hand on the foramen and retract the upper lip with thumb and index finger. Insert the needle in the superior gingival buccal sulcus above the canine tooth root and direct the needle towards your long finger while injecting 2 cc. You may also inject percutaneously by identifying the infraorbital foramen about 1 cm below the orbital rim just medial to the mid-pupillary line. Enter perpendicular to the skin, advance the needle to the maxilla, and inject about 2 cc (Fig. 2.6).12





Lower lip and chin (mental nerve)


Anatomy: The mental nerve exits the mental foramen about 2 cm inferior to the alveolar ridge below the second premolar. The nerve can often be seen under the inferior gingival buccal mucosa when lower lip and cheek are retracted. It branches superiorly and medially to supply the lower lip and chin.


Method: The lower lip is retracted with the thumb and finger of the nondominant hand and the needle inserted at the apex of the second premolar. The needle is advanced 5–8 mm and 2 cc are injected (Fig. 2.7). When using the percutaneous approach, insert the needle at the mid-point of a line between the oral commissure and inferior mandibular border. Advance the needle to the mandible and inject 2 cc while slightly withdrawing the needle (Fig. 2.8).12






Ear (auriculotemporal nerve, great auricular nerve, lesser occipital nerve, and auditory branch of the vagus (Arnold’s) nerve)


Most ear injuries will not require a total ear block and can be managed with local infiltration of anesthetic. While there is a theoretical concern of tissue necrosis when using epinephrine in any appendage (in medical school we learned “finger, toes, penis, nose, and ears”), there is no good data to support this. Most plastic surgeons routinely use 1:100 000 epinephrine in the local anesthetics for ear infiltration. The advantages are prolonged duration of anesthesia and less bleeding. Complications attributed to the anesthetic infiltration are extremely rare.


Anatomy: The anterior half of the ear is supplied by the auriculotemporal nerve that branches from the mandibular division of the trigeminal nerve (CN V3). The posterior half of the ear is innervated by the great auricular and lesser occipital nerves that are both branches from the cervical plexus (C2, C3). The auditory branch (Arnold’s nerve) of the vagus nerve (CN X) supplies a portion of the concha and external auditory canal.


Method: Insert a 1.5 inch needle at the junction of the earlobe and head and advance subcutaneously towards the tragus while infiltrating 2–3 cc of anesthetic (Fig. 2.9). Pull back the needle and redirect posteriorly along the posterior auricular sulcus again injecting 2–3 cc. Reinsert the needle at the superior junction of the ear and the head. Direct the needle along the preauricular sulcus towards the tragus and inject 2–3 cc. Pull back and redirect the needle along the posterior auricular sulcus while injecting. It may be necessary to insert the needle a third time along the posterior sulcus to complete a ring block. Care should be taken to avoid the temporal artery when directing the needle along the preauricular sulcus. If the artery is inadvertently punctured, apply pressure for 10 min to prevent formation of a hematoma.



If anesthesia of the concha or external auditory canal is needed, local infiltration will be required to anesthetize the auditory branch of the Vagus nerve (Arnold’s nerve).



General treatment considerations


The ultimate goal is to restore form and function with minimum morbidity. Function generally takes precedence over form, however the face plays a fundamental role in emotional expression and social interaction, and therefore the separation of facial appearance from function is impossible.



Irrigation and debridement


Once good anesthesia has been obtained, the wound should be cleansed of foreign matter and clearly nonviable tissue removed. This is the process of converting an untidy to a tidy wound. Clean lacerations from a sharp object will result in little collateral tissue damage or contamination, while a wound created by an impact with the asphalt will have significant foreign material and soft tissue damage. The process starts by irrigating the wound with a bulb syringe, or a 60 cc syringe with an 18-gauge angiocatheter attached to forcibly irrigate the wound. More contaminated wounds may benefit from pulse lavage systems.


After irrigation, hemostasis should be secured to give the surgeon a better opportunity to inspect the wound. The use of epinephrine in the local anesthetic will cause some degree of vasoconstriction and assist in this regard. Electrocautery should be applied at the lowest setting conducive to coagulation, and applied to specific vessels. Wholesale indiscriminate application of electrocautery causes unnecessary tissue necrosis. Use electrocautery cautiously when working in areas where important nerves might be located to avoid iatrogenic injury. Remember that nerves often are in proximity to vessels.


Limited sharp debridement should be used to remove clearly nonviable tissue. In areas where there is minimal tissue laxity, or irreplaceable structures (e.g., tip of nose, oral commissure) debridement should be kept to a minimum and later scar revision undertaken if needed. Areas such as the cheek or lip have significant tissue mobility debridement and will tolerate more aggressive debridement.


After the preliminary debridement and irrigation, a methodical search for foreign material should be undertaken. Small fragments of automobile glass become embedded through surprisingly small external wounds. They are usually evident on X-ray or CT scan or by careful palpation. Patients thrown from vehicles will often have dirt, pebbles, or plant material embedded in their wounds. Patients who have blast injuries from firearms or fireworks may have paper, wadding, or bullet fragments present. One should not undertake a major dissection for the sake of retrieving a bullet fragment, however one should make sure that other identifiable pieces of foreign matter are removed. Failure to do so may result in later infection.




Traumatic tattoo


There are two basic types of traumatic tattoo; those that result from blast injuries and those result from abrasive injuries. In either case various particles of dirt, asphalt, sand, carbon, tar, explosives, or other particulate matter is embedded into the dermis.


Abrasive traumatic tattoos are more common. Typically, a person is ejected from a vehicle, or thrown from a bicycle and subsequently grinds their face into the pavement. This causes a simultaneous traumatic dermabrasion of the epidermis and superficial dermis, and embedding of the pigment (dirt). If left untreated, the dermis and epidermis heal over the pigment resulting in a permanent tattoo (Fig. 2.11).



Blast type injuries seen in military casualties and civilian powder burns, as well as firework, and bomb mishaps produce numerous particles of dust, dirt, metal, combustion products, un-ignited gunpowder, and other foreign materials that act like hundreds of small missiles, each penetrating the wound to various depths. The entry wounds collapse behind the particle, trapping them within the dermis.


Regardless of the mechanism of injury, prompt removal of the particulate matter results in a far better outcome than later removal. Once the skin has healed the opportunity to remove the particles with simple irrigation and scrubbing is lost. The initial treatment is vigorous scrubbing with a surgical scrub brush or gauze and copious irrigation.1317 Wounds treated within 24 hours show substantially better cosmetic outcome than those treated later,15 however some improvement has been seen as late as 10 days.18 Larger particles should be searched for and removed individually with fine forceps or needles, loupe magnification, and generous irrigation.19 The tedious and time consuming nature of this procedure may require serial procedures over several days to complete, nonetheless meticulous debridement of the acute injury is the best opportunity for optimal outcome.


The treatment of a traumatic tattoo remains an unresolved problem in plastic surgery, and as such, there are multiplicities of techniques, none of which are perfect. Some of the treatment options include surgical excision and microsurgical planning,20,21 dermabrasion,2225 salabrasion,26 application of various solvents such as, diethyl ether,16 cryosurgery, electrosurgery, and laser treatment with carbon dioxide, argon lasers,13,14,16,27 Q-switched Nd:YAG laser,28,29 erbium-YAG laser,30 Q-switched alexandrite laser,31,32 and Q-switched ruby laser.33,34 The mechanism for laser removal is not entirely understood but is thought to involve the fragmentation of pigment particles, rupture of pigment containing cells, and subsequent phagocytosis of the tattoo pigment.35,36 Laser therapy for pigment tattoos will require slightly higher fluencies than those used for removal of professional tattoos.33


A note of caution is in order when treating gunpowder traumatic tattoos. Several authors have noted ignition of retained gunpowder during laser tattoo removal,29,37 resulting in spreading of the tattoo or creation of significant dermal pits. If initial laser treatment suggests the presence of un-ignited gunpowder in the dermis, laser removal should be discontinued in favor of other treatments such as dermabrasion or surgical micro-excision of the larger particles.



Simple lacerations


Sharp objects cutting the tissue usually cause simple or “clean” lacerations. Lacerations from window and automobile glass, or knife wounds are typical examples (Fig. 2.12). Simple lacerations may be repaired primarily after irrigation and minimal debridement, even if the patient’s condition has delayed closure for several days. When immediate closure is not feasible, the wound should be irrigated and kept moist with a saline and gauze dressing. Prior to repair, foreign bodies such as window glass should be removed. Wounds of this type usually require little or no debridement. A few well placed absorbable 4-0 or 5-0 sutures will help align the tissue and relieve tension on the skin closure. The temptation to place numerous dermal sutures should be avoided because excess suture material in the wound will only serve to incite inflammation and impair healing. The skin should be closed with 5-0 or 6-0 nylon interrupted or running sutures; alternatively, 5-0 nylon or monofilament absorbable running subcuticular pullout sutures can be placed. Any suture that traverses the epidermis should be removed from the face in 4–5 days. If sutures are left in place longer than this epithelization of the suture tracts will lead to permanent suture marks know as “railroad tracks”. Sutures of the scalp may be left in place for 7–10 days. Pullout sutures should usually be removed following the same guidelines, however there less risk of permanent suture marks.




Complex lacerations


When soft tissue is compressed between a bony prominence and an object, it will burst or fracture resulting in a complex laceration pattern and significant contusion of the tissue. Typical examples of these types of lacerations are a brow laceration sustained when a toddler falls onto a coffee table, or an occupant is ejected from a vehicle in a crash striking an object (Fig. 2.13). Many wounds on first impression suggest that there is significant tissue loss, however after irrigation, minimal debridement, and careful replacement of the tissue fragments piece by piece it becomes apparent that most of the tissue is present (Fig. 2.14). Contused and clearly nonviable tissue should be debrided. Tissue that is contused, but has potential to survive should usually be returned to anatomic position. Elaborate repositioning of tissue with Z-plasties and the like should usually be reserved for secondary reconstructions after primary healing has finished. Limited undermining may be used to decrease tension and achieve closure, however wide undermining is rarely indicated. It is probably better to accept a modest area of secondary intention healing and plan for later scar revision rather than risk tissue necrosis from overzealous undermining of already injured tissue.





Avulsions


Many wounds of the face suggest tissue loss upon initial inspection, but closer examination reveals that the tissue has simply retracted or folded over itself. Avulsive injuries that remain attached by a pedicle will often survive, and the likelihood of survival depends on the relative size of the pedicle to the segment of tissue it must nourish. Fortunately, the remarkably good perfusion of the face allows for survival of avulsed parts on surprisingly small pedicles. If there is any possibility that the avulsed tissue may survive it should be repaired and allowed to declare itself. If venous congestion develops it should be treated with medicinal leeches until the congestion resolves. Reconstruction of a failed reattachment can always be undertaken later, but a discarded part can never be replaced.


Many avulsed and amputated parts are amenable to replantation provided that the patient does not have underlying injuries or medical conditions that would preclude a lengthy operation. Examples of facial parts that have been successfully replanted include: scalp, nose, lip, ear, cheek. Vein grafts are often needed to complete the replantation, and venous congestion is a common complication that can be successfully manages with leeches or bleeding the part.


If tissue is truly missing such that primary repair cannot be accomplished then a more complex repair with an interpolation flap or other reconstruction may be needed. These specific techniques for specific areas are covered elsewhere.




Treatment of specific areas



Scalp


Most scalp injuries are the result of blunt force injuries sustained in road crashes, assaults, and falls. Motor vehicle crashes cause most of the avulsive injuries, while complete avulsion of the scalp happens in industrial or farm accidents when the hair becomes entangled around a rotating piece of machinery.


Scalp injuries can generally be evaluated with inspection and palpation of the scalp. One should determine if there is underlying unrecognized skull or frontal sinus fracture by palpation of the wound or X-ray examination.


The thickness of the skin of the scalp ranges from 3 to 8 mm making it some of the thickest on the body.40 The galea is a strong relatively inelastic layer that is an important structure in repair of scalp wounds. It plays a role in protecting the skull and pericranium from superficial subcutaneous infections, provides a strength layer when suturing, and limits elastic deformation of the scalp often making closure more difficult.


The subgaleal fascia is a thin loose areolar connective tissue that lies between the galea and the pericranium and allows scalp mobility. The emissary veins cross this space as they drain the scalp into the intracranial venous sinuses. This is a potential site of ingress for bacteria contained within a subgaleal abscess leading to meningitis or septic venous sinus thrombosis although the incidence is very low.4144

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Feb 21, 2016 | Posted by in General Surgery | Comments Off on Facial trauma

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