The basic goal of the first aid is to save life of an injured person. First aid can be either technical which removes causes of an injury (rescue work, elimination of physical or chemical influences), or medical. The effectiveness of first aid depends on abilities and equipment of persons who perform it. Delivering the first aid to persons with facial injuries has to follow general rules supplemented with a specific procedure as follows:
Freeing airways from foreign objects, blood and vomits; placing a person at the stabilized position, i.e. lying at his/her side with the head turned aside, or lying on his/her belly with the head bolstered (prevents choking and aspiration of saliva, blood etc.)
Bleeding is stopped with a bandage; bleeding from an artery is stopped by pressing the artery against a bone. Tamponing can be used to stop bleeding from nose or open wound..
Transport of a patient to the nearest medical facility or directly to a specialized clinic.
Injuries of the lower jaw.
The lower jaw with its U-shaped bone is an exposed edge part of the facial skeleton.
The lower jawbone is covered with a compact bone tissue of various thickness. It is the thickest at the chin area outside of the third molars and at the bottom ridge. At the lower part of the jawbone’s branch and its body, there is the mandibular canal that appears as a lighter band inside the spongy tissue on X-ray images.
The knowledge about the canal’s route and position is important for placement of osteo-synthetic materials. The alveolar ridge is seated on the jawbone’s body. The alveolar ridge gets atrophied upon the teeth loss at old age. The mandible is attached to the skull by ligaments and mandibular joints.
Muscles that are attached to the lower jaw play a basic role in shifting pieces of broken bone. A group of depressors attach to the front part of the lower jawbone (m. mylohyoideus, geniohyoideus, genioglossus and the front belly of m. digastricus). These muscles draw the lower jaw downwards and backwards while resting against the hyoid bone positioned opposite to the mandible caudally and dorsally and fixed by draw of muscles downwards. Pieces of bone are drawn by these muscles generally downwards and to the front.
The group of elevators that attach to the back part of the lower jawbone (m. pterygoideus med., m. masseter, m. temporalis) draw pieces of bone upwards and more to the front.
Blood supply to the lower jawbone is ensured by two systems. The central system stems from a. alveolaris inf., and the peripheral system from the periosteum. Heavy bleeding does not occur during fractures of the lower jawbone.
10.3 Mandibular Fractures
Blunt impacts of moderate intensity cause just bruises and tearing of the periosteum or formation of subperiosteal hematoma. Providing the intensity of a hit does not cause complete interruption of a bone integrity, dislocation of bone fragments does not happen. Resulting defect thus does not affect the whole width of a bone. A fracture with no dislocation of fragments has its fracture line extended clearly along the whole bone’s width, no shifting or deformation is apparent on its edges (this has to be evaluated from two perpendicular projections). Breakage is narrow, sharp and has no interspersed fragments. Even during a complete bone interruption at children, parts of the bone may remain entangled and unshifted due to a strong and flexible periosteum which stays unharmed (“green stick” fracture). Fractures with fragments dislocation have their edges visibly shifted, the breakage is widened and often contains a tooth root or a retained tooth. Fragments are mutually shifted to sides - ad latus, in angles - ad axim, the bone may also be extended or shortened.
According to the number of fracture lines, fractures can be divided into single, double, triple and multiple. The breakages character may be either multiple or comminuted. If a bone tissue is lost (such as gunshot wounds), a defective fractures occur.
Mechanism of wounds.
The lower jaw’s prominent position makes it a body part exposed to traumas. The most frequent causes of a trauma are direct impacts of objects onto parts of the lower jaw ridge or body (a hit by fist, kick, moving objects etc.). Other causes include an impact of moving head to a solid obstacle (falling, hitting a steering wheel at road accidents etc.). During impacts onto the chin area or sides of the lower mandibular, an indirect fracture of one or both articular processes occurs by transferring an impact force onto them. Parts of the lower jawbone that have reduced thickness due to deposition of retained teeth (wisdom teeth) or by the length of a canine tooth’s root are predisposed locations for fractures.
Classification of the mandibular fractures.
For a practical use, fractures of the lower jaw can be divided into the following classes:
Fractures of the alveolar ridge
Most often, a fracture appears at the front section. There are usually more fracture lines that descend through the teeth sockets vertically, and a horizontal line divides the ridge from the body at the apex area. Dislocation by an impact appears at the direction towards the tongue. Simple reposition is possible under a good anesthesia, however, teeth roots sometimes prevent from placing a bone fragment into its proper position. Affection of the alveolar ridge is often associated with damages of the teeth.
Fractures of the mandible toothed section
At the middle part of the jawbone, fractures usually do not run perfectly vertically along the symphysis, but rather sideways. In cases of double-sided fractures at the canine teeth area, a fragment of the chin may be pulled backwards by tension of the front depressors. Support of the tongue is thus damaged, causing the tongue to get stuck in the throat followed by suffocation.
Lateral fractures result either from a direct impact at a place of its effect or on the other side of the jawbone by transferring its force there. Muscle tension is ultimate for dislocation of fragments. In general, a short fragment is pulled upwards, especially when the dental arch is shortened on the affected side and an interdigitation of antagonists is not present. Lateral fractures use to be double, i.e. on both sides of the jawbone. Although the presence of teeth at this part of the lower jaw may cause complications (teeth damage or its presence at fracture line), these fractures can be cured easily and successfully by conservative means, i.e. by a firm intermaxillary fixation for 4 weeks.
Fractures behind rows of teeth
At the teethless distal sections (a retained third molar is often placed here), the bone’s thickness is reduced and its fracture can occur after hitting with a fist (on the left side after a blow of a right-handed person who stands opposite to a victim). If a fracture line runs below the attachments of the strong masseter which encompasses both fragments, a dislocation is not apparent. However, if pulling upwards prevails and if there is a retained tooth present at the fracture line, surgical treatment including the tooth extraction followed by osteosynthesis, is the only correct way of treatment.
Fractures of mandibular rami are less common. Most often they arise from a direct impact. Dislocation is usually not significant, these fractures do not require surgical treatment, and an intermaxillar fixation is sufficient for healing.
Fractures of the articular process
These indirect fractures appear frequently. The lower jawbone is very thin at its neck area which can be regarded as a kind of protective mechanism. This part prevents by its breakage the joint head from penetration into the middle cranial space. A direct fracture of the joint process can result for instance from a gunshot wound. These fractures can be either extracapsular or intracapsular. A fracture with no significant dislocation should be treated by resting for 3 weeks followed by rehabilitation of the mouth opening. Luxation fractures belong to those rare injuries of the articular process that require surgical repositioning and fixation.
Fractures of the muscular process
These fractures are very rare injuries. If the coronoid process under the zygomatic arch blocks opening of mouth, it should be removed from intra-oral access. No fixation of fractures is required, however, an immediate rehabilitation of mouth opening is necessary.
Fractures of a edentulous or sparsely toothed jawbone
After reposition of fragments, it is not possible to make any immobilization with dental splints or intermaxillar fixation. Fixation with the aid of resin occlusal humps, interconnected inside the mouth and reinforced from the outside by “headstall” bandages, is rather symbolical than functional. For this reason, this kind of fractures is often treated surgically, currently using mini-splints or functionally stabilizing bone splints and screws.
Are characterized by a bone loss during a gunshot wounding or an explosion. Reconstruction is made by a combined treatment including the transfer of a bone transplant and fixation of the fracture (autotransplants from the illiac crest or a rib).
Symptoms of fractures
Characteristic signs of the lower jawbone fractures are the following:
Appears in the forms of spontaneous, functional or pressure pain. At the moment of an injury, an affected person feels a blunt or sharp pounding pain. Pain is later sensed during movements of jaws, opening, closing and biting. It is mostly located at the wounded area. In cases of non-dislocated fractures, this pain can be initiated by pulling the jaw forward by a finger hooked in it, thus identification a broken site.
Deformation of the face
Deformation of the lower jaw’s shape can be observed at highly dislocated fractures only. An injured place gets swollen or a subcutaneous hematoma appears shortly after an injury.
Impairment of chewing is always present at fractures of the alveolar ridge or teeth - containing parts of the jaw. Teeth do not touch each other (do not articulate) and the food mastication function is hampered. Mouth opening and closing is restricted mainly while jaw’s branches and articular processes are broken. Swallowing function is restrained mostly by pain which may make difficult even swallowing of the saliva that ooze from the mouth. In cases of bilateral fracture at the canine teeth areas, the tongue gets stuck and breathing problems appear.
Pathological motion and crepitation of fragments
A pathological motion that can be induced upon a patient’s examination is a doubtless evidence of a bone fracture. During friction of ragged bone fragments onto each other, it is possible to hear and feel their crepitation under examining fingers.
Therapy of the lower jaw fractures
Only absolutely non-dislocated fractures with sufficiently firm entanglement of fragments at their normal anatomical positions do not require any repositioning. Simple fractures of teeth-containing jawbones undergo a single manual reposition into a correct mutual position, after needed anesthesia. A gradual, slow repositioning by pulling with rubber hitches or orthodontic appliances is also feasible. In order to keep the resulting position of fragments, fixation by a dental splint is then used. A dental splint is made of a semiround or flat wire, either directly inside a patient’s mouth or indirectly on a dental model. It is necessary to apply a splint to as many firm teeth as possible, to which a splint is attached by wire ligatures (a steel wire 0.4 mm in diameter). A splint provides for fixation of fractures of the alveolar ridge or toothed parts of the jaw body. Sauer’s splint is the most commonly used type at present. Cast metal splints are very firm and functionally suitable, as well.
If an applied splint is reinforced by a fast-hardening resin, it may itself provide for sufficient fixation of simple fractures of the body or alveolar ridge.
A firm intermaxillary fixation ensures a necessary rest needed for healing of fractures of jaws. Such rest can be achieved with the aid of dental splints, applied to both jaws and fitted with wire loops or hooking pins that connect them. Opening of the mouth is thus prevented, jaws are fixed together at an optimal occlusion. This way of fixing possesses a danger of aspiration of blood, vomits or food, however.
Feeding the patients.
During application of fixtures, the food has to be liquid - blended, supplied more often than a regular food, and substituting it sufficiently by its composition and nutritional values. A patient is fed by means of a glass tube or by drinking. Food can be swallowed normally after passing through retromolar spaces, even if a full number of teeth is present. In serious cases, especially at defective fractures of jaws, a patient receives food by a naso-gastric tube inserted through the nasopharynx. An intermaxillary fixation does not allow a patient to speak, it possesses a social handicap and requires a home stay in majority of cases.
Fixation of edentulous jaws by a mono-block.
If jaws are edentulous and dental splints cannot be used, immobilization of fragments is achieved by laboratory made resin blocks, that are interconnected inside the mouth thus forming a mono-block. Fixation has to be supplemented by an outside by “headstall” bandages - a rubber band or an elastic bandage.
Duration of immobilization.
Immobilization of jaw movements in cases of non-complicated fractures of the body, angle, alveolar ridge or ramus should be for 4 weeks (28 days). Fractures of the articular process should be immobilized for 3 weeks. For children, immobilization times shorter by one week are used. Duration of fixation by the dental splint itself should be determined by a fracture location, its nature and course of healing.
After releasing the intermaxillar fixation, it is necessary to reestablish the mouth opening by chewing muscles exercises and movements of the mandibular joint. Heat effects (“Solux” lamp) and various mechanical mouth props are used.
Wire attachments, splints and intermaxillar fixtures hamper self-cleaning abilities of the teeth and gums and urge a patient or medical personnel to do the teeth cleaning 6 to 8 times a day. A toothbrush and toothpaste are used regularly, an irrigation can be used if there is no injury to soft tissues. Patients who are immobilized or unconscious have to have their teeth cleaned chemically (Chlorhexidin).
The aim of current therapy methods is exposing and release of bone fragments, repositioning them followed by fixation at a proper position, performed under a visual control.
Osteosynthesis means connecting fragments by means of artificial, mostly metal, materials. Connecting elements can be wires, bone splints, screws, clinches and other parts.
Bone fragments are most often joined together directly by bone wire stitches (a soft steel wire 0.3-0.4 mm in diameter). Stitches can be single, double, cross-like etc. They are inserted into apertures made at bone fragments edges. They should hold these fragments together in a mutual contact (adaptive osteosynthesis). Connection of bone fragments cannot be made firm enough to ensure keeping fragments together without dental splints or intermaxillary fixation.
Bone splints that are fixed by screws ensure a firm connection so that no other supporting immobilization of jaws by intermaxillary fixation is needed. A danger of aspiration of foreign objects is thus eliminated and allow for suction from airways of unconscious patients or an intubation for general anesthesia, as well as better communication with a patient and good oral hygiene.
At the end of the sixties, efforts of Swiss orthopedists and engineers resulted in design of instruments for firm connections of broken bones with help of bone splints and screws fastened into screwed holes with sharp threads. This is the only way of preserving the “live” bony tissue around screws and maintaining a long-term stability of fixation. Splints and screws had been made of austenitic (stainless) steels originally. Today, they are made of almost pure titanium. Splints and screws are absolutely biologically inert for tissues. Due to their massiveness, they had to be removed from an organism after a fracture has healed.
Mono-cortical minisplints and screws.
Attempts to minimize bone splints and screws in use has led the authors to design of the miniplate fixation system (Champy, Pape and others) and to determine the most appropriate placement of splints at different types of the lower jaw fractures. Muscle attachments and draw effects of strong chewing muscles are limiting factors for placement, shape and number of splints. A splint is then fixed to a bone with screws, anchored in the compact tissue. Also these splints and screws are removed after a bone heals (4-5 months).
Other means of osteosynthesis.
If a fracture line slit runs oblique, e.g. at the body of a edentulous jaw, it is possible to perform osteosynthesis by a wire sleeve (circlage). It is also possible to connect fragments by a clinch or a nail (Kirschner’s wire) whose one end sticks out from the skin during healing period and facilitates its removal.