FASCIAL SPACE INFECTIONS
‘I he spaces that are involed directly are known as the of primary involvement, The principal rnaxu. lary primary spaces arc the canirio, buccal, and infratemporal spaces (Box 16·1). The principal mandibular primilry spaces arc the buccal, and sublil guill spaces, Infections can extend beyond these primary spaces into additional fascial space, nr svcondary spaces.
Spaces Involved in Odontogenic Infection
Primary Maxillary Spaces
Primary Mandibular Spaces
Seco”iary Fascial Spaces
• Masseteric ‘
• Superficial and deep temporal
• lateral pharyngeal
The canine space is a thin potential space between the levator angulioris and the levator labii superioris muscles: The canine space becomes involved primarily as the result of infections from the maxillary canine tooth.
This is the only tooth with a root, sufficiently long to allow erosion to occur through the alveolar bone superior to the muscles of facial expression. The infection erodes superior to the origin of the levator anguli oris muscle and below the origin of the levator labii supcrioris muscle. When this space is infected, swelling of t hc anterior face obliterates the nasolabial fold Spontaneous drainage of Infections of this space COIllmonly occurs just Infenor to the medial canthus of till” eye.
Involvement of ‘the buccal space usually results, In swelling below the zygomatic arch and above the i.nferior border of the ‘mandible. Thus both the zygornattc arch and the inferior border of the mandible are palpable in buccal space infections.
Cavernous sinus thrombosis may also occur as the result of superior spread of odontogenic infection a a hematogenous route (Fig. 16-5). Bacteria may travel from the maxilla posteriorly via the pterygoid plexus and emissary veins or anteriorly via the angular vein and inferior or superior ophthalmic veins to the cavernous sinus. The veins of the face and orbit lack valves, which permits blood to flow in either direction. Thus bacteria can travel via the venous drainage system and contaminate the cavernous inus, which results in thrombosis. Cavernous sinus hrombosis is an unusual occurrence that is rarely the result of an infected tooth. Like orbital cellulitis, cavernous sinus thrombosis is a serious; life-threatening infection that requires aggressive medical and surgical care. Cavernous sinus thrombosis has a high mortality even today.
Although most Infcctlons of the mandibular teeth erode into the buccal vestibule, they may also spread in a fascial spaces. The.four primary mandibular spaces re 1) the submental, (2) the buccal, (3) the sublingual, and (4) the submandibular spaces.
The sublingual and submandibular spaces haw the medial border of the mandible as their lateral boundary. These two involved primarily by lingual perforation of infection from the mandibular molars, although they may be involved by premolars, as well. The factor, that determines whether the infection is submilLlQ,ibular or sublingual is the attachment of the mylohyoid muscle on the mylohyoid ridge of the medial aspect of the mandible (Fig. 16-7). If the infection erodes through the medial aspect of the mandible above this line, the infection wiII be in the sublingual space and is most commonly seen with premolars .and the lirst molar. If the infection erodes through the medial aspect of the mandible inferior to the mylohyoid line; the submandibular space will be involved. The mandibular third molar is the tooth that most commonly involves the submandibular space” primarily. The second molar may involve either the sublingual or submandibular space, depending on the length of the individual roots, and may involve both spaces primarily.
l he submandibular space between the mylohyoid muse k- and the overlying skin and superficial fascia posterior boundary of the submandibular space communicates with the secondary spaces of the jaw posteriorly. Infection of the submandibular space causes swelling that begins at the inferior border of the, mandihle and extends medially to the digastric muscle and posteriorly to the hyoid bone (Fig. 16·10).
The patient usually has trismus, drooling of saliva, and difficulty with swallowing and sometimes breathing. The patient often experiences severe anxiety concerning the inability to swallow and maintain an airway, This infection may pogress with alarming speed and thus may produce upper airway obstruction that often leads to death. The most common cause of Ludwig’s angina is an odontogenic infection, usually as the-result of streptococci. This infection must be aggressively managed with vigorous I&D procedures and aggressive antibiotic therapy. Special attention must be given to maintenance of the AIRWAY.
Secondary Fascial Space
The primary spaces discussed so far are immediately adjacent to the tooth-bearing portions of the maxilla and mandible. If proper treatment is not received for infections of the primary space 1 the infections may extend posterioriy to involve the secondary fascial spaces. When these spaces are involved, the infections frequently
become more severe, cause greater complications and greater morbidity, and are more difficult to treat. Because a connective tissue fascia that has a poor blood supply surrounds these spaces, infections involving these spaces are difficult to treat without surgical inter ention to drain the purulent exudate.
The pterygomandibular space lies medial to the mandible and lateral to the medial pterygoid muscle (see Fig. 16-4). This is the space into which local anesthetic solution is injected when an inferior alveolar nerve block is performed. Infections of this space spread primarily from the sublingual and submandibular spaces. When the pterygomandibular space alone is Involved, little or no facial swelling is observed; howev r, the patient almost always has significant trismus. Therefore trismus without swelling is a valuable diagnostic due for pterygomandibular space infection,. The most common occur
rcnce of this clinical picture is caused by needle tract infection from a mandibular block.
When taken as a group, the masseteric, pterygomandibular, and temporal spaces are known as the masticator space, because the rnuscles and fascia of mastication bound them. These spaces communicate freely with one another, so.when.one becomes involved the others may also. The term masticator space does have some general clinical usefulness, but it lacks spedftctty and is therefore less useful than specific space designations.
Cervical Fascial Spaces
Extension of odontogenic infections beyond the primary and secondary mandibular spaces is an uncommon occurrence. However, when it does happen, spread to deep cervical spaces rnay have serious life-threatening sequelae. These sequelae may be the ‘result of locally induced complications, such as upper airway obstructions, or of distant’ problems, such as mediastinitis.
The clinical findings of lateral pharyngeal space infection include severe trismus as the result of involvement of the rnedial pterygoid muscle; lateral swelling of the neck, especially inferior to the angle of the mandible and swelling of the lateral pharyngeal wall, toward the midline. Patients who have lateral pharyngeal space infections have difficulty swallowing and usually have a high temperature and become quite sick.
Patients who have infection of the lateral pharyngeal space have several serious potential problems. Whep the lateral pharyngeal space is involved, the odontogenic infection is severe and may be progressing at a rapid rate.
Anotlier possible problern is the direct effect of the infection on the contents of the space, especially those of the posterior compartment. These problems include thrombosis of the internal jugular vein, erosion of the carotid artery or it~ branches, and interference with cranial nerves IX through XII.A third serious complication arises if the infection progresses from the lateral pharyngeal space to the retropharyngeal space.
When a patient has extension of infection into the cervical region, the retropharyngeal space must be evaluated with lateral radiographs of the neck to determine if the space is enlarged and thereby compromising the airway (Fig. 16-13).
When the retropharyngeal or prevertebral fascial spaces (or both) are involved as a result of odontogenic infection, the patient is almost always seriously ill. The following are the three greatest potential complications;(1) the serious po sibility of upper-airway obstruction as a result of anterio displacement of the posterior pharyngeal wall into the oral pharynx: (2) rupture of the retropharyngeal space abscess, with aspiration of pus into the lungs and subsequent asphyxiation; and (3) spread of the infection from the retropharyngeal spaces into the mediastinum, which results in severe infection in the thorax.
Management of Fascial Space infections
Management of infections, mild or severe, always has five general goals: (J) medical support of the patient. with special at termon to correcting host defense compromises where they exist: (2radministration of proper antibiotics in appropriate doses; (3) surgical removal of the source of infection as early as possible; (-l) surgical drainage of the infection, with placement of proper drains; and (5) constaut. recvaluatlon of the resolution of the .infcction. The principles of surgical and medical management of fascial space infections are the same as those tor less sericus infections, However, fascial space infections require more extensive and aggressive treatment .
Surgical management of fascial space infections almost always requires a generous Inclsion and aggressive exploration of the involved fascial spaces with a hemostat. One or more drains are usually re-quired to provide adequate drainage and decompression of the infected area. Because i&D must be extensive, they are usually done in an operating room, with the patient under general anesthesia. The locations’ of various I&D sites are depicted in Fig. 16-1-1. Ample clinical experience and experimental evidence indicate that, although no pus formation can be detected by palpation or even by needle aspiration, even the serious cellulitis will resolve more rapidly if incised. The surgeon must not wait for unequivocal evidence of pus formation. In the preantibiotic era, surgical treatment was the only method of therapy for infections, and early and aggressive surgical therapy was frequently curative for these severe infections. It is important to remember, . that aggressive surgical exploration is still the primary method of therapy for serious odontogenic infections of the head and neck.