------------------------------------------------------------------------------- TITLE: FASCIAL COMPARTMENT OF THE NECK SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: December 6, 1994 FACULTY: BRIAN P. DRISCOLL, M.D., ASSISTANT PROFESSOR DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------------- "This material was prepared by physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." The study of the fascial layers of the head and neck and the potential spaces they make-up is both fascinating and confusing. Much of the confusion is a function of the multiple synonymous terms that various authors use, and not the basic anatomical description. The fascial spaces of the neck were first described by Burns in 1811. As early as 1838 the french anatomist Malgaine remarked "the cervical fascias appear in a new form under the pen of each author who attempts to describe them." Over the past 160 years this problem has gotten worse. Presently, not only do anatomists and surgeons attempt to define these spaces but with the advent of CT scans and space specific diagnosis the radiologists are also naming these spaces. I. Fascias of the Head and Neck. A. Superficial Fascia 1. Extends from the head to the thorax, shoulders and axilla. 2. Envelops the platysma muscle and the muscles of facial expression. 3. Completely encircles the neck. B. Superficial layer of deep cervical fascia 1. Enveloping layer, completely surrounds the neck. 2. Extends from the zygoma to the pectoral and axillary regions. 3. Envelops the parotid and submandibular glands and the trapezius and SCM muscles. 4. The space of Burns and the subvaginal space C. Middle layer of deep cervical fascia 1. Divided into a muscular division and visceral division. 2. The Muscular division surrounds the strap muscles. It extends from the hyoid bone to the sternum, clavicle and scapula. 3. The visceral division surrounds the thyroid, trachea and esophagus. Posteriosuperiorly it extends from the skull base, anteriosuperiorly it extends from the hyoid bone. It then becomes continuous with the fibrous pericardium and continues as the covering of the esophagus and trachea in the chest. D. Deep layer of the deep cervical fascia 1. Divided into a prevertebral and alar layer. 2. Prevertebral layer - from the base of the skull to the coccyx. It extends from the transverse process around the deep muscles of the neck and anterior vertebral bodies to re-insert on the spinous processes. 3. Alar layer - Extends from the base of the skull to T-2 and laterally from transverse spinous process to transverse spinous process. It lies between the prevertebral fascia and the posterior visceral fascia to which it fuses to at T-2. E. Carotid sheath The carotid sheath is derived from all three layers of the deep cervical fascia. Mosher called this the "Lincon Highway" of the neck. It extends from the base of the skull to the chest. The fascial spaces of the neck can be arbitrarily divided into three divisions. These are: 1) spaces involving the entire length of the neck, 2) spaces above the hyoid bone and 3) spaces below the hyoid bone. This division is based of the fact that the hyoid bone is the most important structure limiting the spread of infection. II. Spaces above the hyoid bone A. Submandibular space 1. Boundaries- mandible (anterior and lateral), mucosa of the floor of the mouth (superior), Hyoid bone (posterior), superficial layer of the deep cervical fascia (inferior). 2. Divided into a sublingual space (above the mylohyoid) and a submaxillary space (below the mylohyoid). 3. Source of infection - Most are odontogenic. In general periapical abscess anterior to the second molar cause sublingual space infections, while those of the second and third molar break through below the mylohyoid and lead to submaxillary infections. Other common routes of infection include submandibular gland or lymph node infection. 4. Symptoms include severe pain, trismus, swallowing difficulties, respiratory distress, swelling of the neck and floor of the mouth. 5. Ludwig's angina was described in 1836. The infection is usually secondary to a 2nd or 3rd molar infection. It is a cellulitis of the submandibular space, drainage yields a putrid serosanguineous fluid. 6. Treatment- ABC's. Many of these patients will require an awake tracheotomy prior to drainage. Drainage (for ludwig's) is through a horizontal submental incisions which divides the platysma, the mylohyoid is then divided in the midline to relieve tension on the floor of mouth. The area is then opened with a clamp, drains are placed, the wound is not totally closed. Small sublingual abscess may undergo intraoral drainage. One sided submaxillary abscess may undergo drainage through a horizontal submaxillary incision being careful to avoid the marginal mandibular nerve. B. Parapharyngeal space 1. AKA- Pharyngomaxillary space, lateral pharyngeal space and peripharyngeal space. 2. An inverted pyramid in shape, the space is bounded by the base of skull (superior), hyoid bone (inferior), pterygomandibular raphe (anterior), prevertebral fascia (posterior) and fascia of the superior constrictor (medial). 3. Divided by styloid process into a prestyloid or muscular compartment and a retrostyloid or neurovascular compartment. 4. This space is frequently involved with infection because of the lymph nodes contained within it and its integral relationship to most of the other spaces. This space serves as the conduit to allow infection to pass from the spaces above the hyoid to those spaces below the hyoid and then into the chest. 5. Symptoms- Prestyloid space- buldging of peritonsillar region, trismus and angle of jaw swelling. Poststyloid - Parotid space swelling and lateral pharyngeal wall swelling but no trismus. Watch for possible vascular thrombosis or hemorrhage. 6. Drainage - External for vascular control. Use a horizontal incision or an incision along the anterior boarder of the SCM. Elevate submandibular gland and finger dissect toward styloid process. Drain and do not close wound totally. C. Masticator space. 1. Boundaries- The superficial layer of the deep cervical fascia splits at the mandible to ensheathe the muscles of mastication, thus the masticator space is bound on all sides by this layer. 2. Most infections are odontogenic in origin, usual from the 2nd and 3rd molar. 3. Symptoms- Extreme trismus is the hallmark of these infections. There may be swelling of the cheeks or in the mouth along the ramus of the mandible. Frequently the most tender area is along the posterior border of the ramus of the mandible. 4. Treatment- Usually external through a horizontal incision below the angle of the mandible. Drain, and do not close wound all the way. D. Parotid space 1. Boundaries - The gland is bound on all sides by the superficial layer of the deep cervical fascia which splits to encapsulate the gland along with its lymph nodes. The fascia is thought to be deficient superiomedially allowing open communication with the parapharyngeal space. 2. Symptoms - Swelling of the parotid at the angle of the mandible without trismus. 3. Treatment- A small abscess can be drained with an incision in the skin over the swelling parallel to the facial nerve and then bluntly dissecting into the abscess with a clamp. Larger abscesses should be drained through a parotidectomy incision. The wound is drained and partially closed. E. Peritonsillar space 1. Most common deep neck infection. 2. Boundaries - Superior constrictor (medial), anterior and posterior tonsilar pillars (superiorly and interiorly). 3. Early abscesses generally extend superior and anterior. Later, posterior extension allows it to decompress into the parapharyngeal space. Remember, all peritonsillar abscesses are potential parapharyngeal or retropharyngeal abbesses. 4. Symptoms - Tonsillitis that worsens despite antibiotics. Patients are usually unable to swallow and have trismus. Exam reveals one tonsil bulging toward the midline displacing the uvula and causing a convexity of the faucial arch. 5. Treatment: Antibiotics (clindamycin/unasyn/augmentin) with: a. Aspiration - 90% effective, 15% require multiple aspirations. Ten percent need other treatment. May be appropriate in patients over 30 years of age without a history of recurrent tonsillitis. b. I&D with interval tonsillectomy - incision at superior pole and dissect with clamp to inferior pole. c. Quinsy tonsillectomy III. Spaces involving the entire length of the neck A. Superficial space 1. Between the superficial fascia and the deep layer of the deep cervical fascia. 2. Site of superficial cellulitis of the neck usual secondary to suppuration of a lymph node. 3. Signs of infection are obvious as these abscesses point and are fluctuant, as opposed to deep space neck infections. 4. Treatment involves local I&D and antibiotics. B. Retropharyngeal space 1. AKA- Posterior visceral space, retrovisceral spate, retro-esophageal space and posterior part of Grodinsky and Holyoke space #3. 2. Boundaries - Base of skull (superior), T-2 (interior), middle layer of deep cervical fascia (anterior) and alar layer (posterior). At T-2 the alar and middle cervical fascias fuse. 3. Main route of spread of infection from the neck to the chest. Infections here can easily breakthrough into the danger space which extends to the diaphragm. 4. Usually caused by suppuration of retropharyngeal lymph nodes receiving drainage from sinuses, adenoids and nasopharynx. 5. Usually a complication of a URI and more common in children. 6. Signs/symptoms - In children: seen after a URI, may cause swallowing difficulties, respiratory distress and fever. The neck is usually held rigid and tilted to the uninvolved side. On oral exam the lesion is typically seen on one side, although more advanced lesions cross the midline. 7. Treatment - ABC's. Watch for rupture and aspiration. These patients may need a tracheotomy prior to drainage. Localized lesions may undergo peroral I&D, extended lesions will need a external excision. Typically this incision is along the anterior border of the SCM, dissection is then carried between the carotid sheath and the constrictor muscles (Dean approach). Drain the wound and do not close the wound. 8. Complications - Include hemorrhage, aspiration and extension into the chest. Mediastinal extension is characterized by chest pain, dyspnea and persistent fever. Initial CT scans must define the inferior extent of the spread of infection. C. Danger space (Grodinsky and Holyoke #4) 1. Boundaries - Between the alar and prevertebral fascia from the base of the skull to the diaphragm. 2. Usually secondary to spread of infection from the parapharyngeal space or the prevertebral space. Allows easy spread into the mediastinum - hence its name: the danger space. 3. Drainage - Similar to that described for the external approach to the retropharyngeal space. D. Prevertebral space (Grodinsky and Holyoke #5) 1. Boundaries - Compact space between the prevetebral fascia and the vertebral bodies, from the base of the skull to the coccyx. 2. Infrequent cause of infection. Generally secondary to TB, osteomyelitis or surgery. 3. Compactness of space generally limits spread into the chest. 4. Drainage is similar to external approach to retropharyngeal space. E. Visceral vascular space (carotid space) 1. The space confined by the carotid sheath, from the base of the skull to the mediastinum. The space is compact and infection does not usually travel within the sheath. 2. Signs/symptoms - Tenderness and induration deep to the SCM along with torticollis toward the uninvolved side. 3. Compilations involve thrombosis or rupture of the great vessels of the neck. A "picket fence" type of fever curve indicates thrombosis of the IJ vein which may require surgical excision of the vein. IV. Spaces limited to below the hyoid. A. Anterior visceral space 1. AKA- Pretracheal space, previsceral space and anterior portion of Grodinsky and Holyoke space #3. 2. Boundaries - Thyroid cartilage (superior), to superior mediastinum at the aortic arch (inferior), between the deep surface of the strap muscles (anterior) and the anterior wall of the esophagus (posterior). In its upper portion it is continuous with the posterior visceral space. 3. Usually infections arise from traumatic perforations of the anterior esophageal wall. 4. Signs/symptoms - Hoarseness, dysphagia, dyspnea, swelling and erythema of the hypopharynx. 5. If the infection is pointing, a localized drainage can be done. For more extensive infections drainage via the Dean approach is useful. V. Treatment A. Microbiology The microbiology of deep neck infections consists of mixed anaerobic and aerobic bacteria with anaerobes predominating. The usual organisms found are those that are normal mouth flora. Despite the anaerobic predominance the most common isolate is aerobic streptococci. The most common anaerobic bacteria are Peptostreptococcus, Fusobacterium and Bacteroides. An important exception to this is the parotid abscess where Staphylocci tend to predominate. Gram-negative rods are not normal oral fora in health adults. The colonization rate is increased in diabetics, hospitalized patients and chronic alcoholics. Thus, these bacteria may participate in the infectious process in these patients. Eikenella corrodens is an emerging pathogen in deep space neck infections, especially when secondary to IVDA. This organism has the distinction of being one of the only anaerobes to be resistant to clindamycin. B. Antibiotics The antibiotic choice should obviously reflect the pathogens. Prior to culture results common pathogens should be covered. This includes gram-positive cocci and anaerobes. Good initial choices include high-dose PCN and metronidazole or chloramphenicol. Clindamycin alone may be a reasonable choice, however the emergence of Eikenella corrodens as a pathogen must be remembered. C. Airway Management The judicious management of the airway is especially important for retropharyngeal and submandibular space infections. Patients with Ludwig's angina can experience rapid deterioration of their airway and expeditious care is crucial to avoid disaster. Techniques of airway management include awake intubation, fiberoptic intubation and awake tracheotomy. Of these, it is the authors' opinion that awake tracheotomy provides the safest airway management. D. Surgical Incision and drainage is almost always part of the treatment. There are two main routes of drainage: intraoral vs. extraoral. Intraoral drainage is appropriate for peritonsillar abscesses and small retropharyngeal or sublingual abscesses. Extraoral drainage is most appropriate for all other abscesses. The incision is either submental (ludwig), submandibular or along the anterior boarder of the SCM. In general the wounds should be drained and left open or only partially closed. ---------------------------------------------------------------------------- BIBLIOGRAPHY 1. Beck HJ, Salassa JR, McCaffrey TV, Hermans PE. Life-Threatening Soft-Tissue Infections of the Neck. Laryngoscope 1984;94:354-361. 2. Blomquist IK, Bayer AS: Life-threatening Deep Fascial Space Infections of the Head and Neck. Infectious Disease Clinics of North America 1988;2(No. 1):237-251. 3. Holt GR, McManus K, Newman RK, Potter JL, Tinsley PP: Computed Tomography in the Diagnosis of Deep-Neck Infections. Arch Otolaryngol 1982;108:693-696. 4. Johnson JT: Abscesses and Deep Space Infections of the Head and Neck. 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