Marshall Guy, M.D.

Disclaimer: The information contained within the Grand Rounds Archive is intended for use by physicians and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at Baylor College of Medicine in Houston, Texas. No warranties, either express or implied, are made with respect to accuracy, completeness or timeliness of this material. This material does not necessarily reflect the current or past opinions of the faculty of Baylor College of Medicine and should not be used as a basis for diagnosis or treatment, and is not a substitute for professional consultation and/or peer-reviewed medical literature.

We will begin with a case presentation, discuss some of the history of deep space neck infections, and go over the relevant anatomy including the fascial planes and deep spaces, as well as review current trends in treatment modalities for deep space neck infections.

We were consulted to evaluate for a peritonsillar abscess in a patient who had previously had a tonsillectomy. The patient was a 17-year-old female with a remote history of a tonsillectomy and two endoscopic sinus surgeries, who presented to the TCH ER with a 9-day history of odynophagia. Six days prior to presentation, the pain peaked and the mother treated the patient symptomatically with Advil and the pain improved but did not resolve. Then, 4 days prior to presentation, the patient developed a “head cold” which was treated with Afrin, Nasonex, and nasal saline, which improved. However, 2 days prior to presentation, the odynophagia worsened once again and the patient began to have significant left otalgia. At that time, she was seen in the TCH ER and given Amoxil for a presumed left ear infection. The patient did not tolerate the antibiotics and presented back to the TCH ER with temperature of 101.5°F and inability to tolerate PO.

Physical exam was significant for minimal fullness of left posterior oropharynx without erythema but the patient did have limited range of neck motion to the left and tenderness in left level II. CT was performed, which showed a paravertebral phlegmon. As you can see on this slide, the hypodensity touches the vertebrae.

The patient was admitted to the pediatric inpatient service for IV antibiotics. Neurosurgery was consulted but deemed no operations necessary. The patient continued to symptomatically improve and was discharged home on hospital day 3 to finish a course of antibiotics.

Having spent 3 months at Texas Children’s, I would imagine that since there have been children with necks, there have been deep space neck infections. However, the literature dates back to 1811 when Burns first described cervical fascia, although not in its current form. Part of the difficulty in the description was something a second year resident knows quite well: it is difficult to dissect out the fascial planes without creating false tracts. The confusion regarding the fascia continued until 1838 when the French anatomist Malgaine best described the situation by saying: “The cervical fascias appear in a new form under the pen of each author who attempts to describe them.” It wasn’t until 1882 when Tillaux described the fascia as having 3 separate layers. Our current understanding was aided by contributions from Grodinsky and Holyoke, and Levitt.

Fascia comes from the Latin word for band or bandage. This is a great description, given the resistance by the fascia to create the various compartments. There are a total of four “fascias” of the neck. The superficial fascia, not to be confused with the superficial layer of the deep cervical fascia, is possibly a misnomer. It is more developed in other mammals, but in humans it is a relatively minimal layer. It is a fibrofatty tissue connecting the skin to the underlying fascia and includes the platysma muscle. Another term is the panniculus adiposus.

However, the cervical fascia we generally refer to includes the three layers of the deep cervical fascia. These layers vary in thickness and consistency with the thickest components in the nonexpansile areas, such as over the sternocleidomastoid, and thinnest over the expansile areas such as the pharynx. The purpose of the fascia is to create planes for the tissues to glide by, for example, with swallowing. This, unfortunately, also creates the potential for infections to develop in the various neck spaces. Once infections do develop, the route of spread depends on numerous factors in addition to the normal fascial planes: previous trauma, surgery, radiotherapy, and infections.

The proposed mechanisms of spread include direct extension, spread via lymphatic drainage, and finally, hematogenous spread.

The superficial layer of the deep cervical fascia is also known as the investing layer. A helpful way of remembering what it encompasses is by remembering the rule of two’s—two pairs of muscles and two pairs of glands: the sternocleidomastoid and trapezius muscles and the parotid and submandibular glands. This diagram shows an excellent representation of this fascial layer with the overlying platysma seen. A further representation of an axial section from the neck clearly shows the encompassing of the muscular groups into the superficial layer of deep cervical fascia.

The middle layer of the deep cervical fascia includes both a muscular and visceral division. The muscular division envelops the strap muscles, attaches to the hyoid bone and thyroid cartilage superiorly, and attaches to the sternum, clavicle, and scapula inferiorly.

The visceral layer envelops the organs in this region including the trachea, esophagus, and thyroid gland. Inferiorly it is in connection with the pericardium. As you look in the midline on this anterior view, you can see the visceral fascia as well as the fascial layer covering the strap muscles. On the cross sectional view you can see the representation of the two divisions. On the sagittal view you can see it extending posteriorly to the esophagus.

The deep layer of the deep cervical fascia also has two components. Posteriorly is the prevertebral fascia, which fuses with the transverse processes and spinous processes of the spine and includes the muscles in the area. It also forms the posterior border of the danger space.  Just anterior to the prevertebral fascia is the alar fascia, which is the second component of the deep layer. It is immediately posterior to the visceral fascia and forms the anterior border of the danger space. And this is again represented on these diagrams.

The carotid sheath is made up of contributions from all three deep cervical fascias and houses the carotid artery, internal jugular vein, and vagus nerve.

Here is a summary slide showing all of the different compartments, which gives a better representation of the alar and prevertebral fascia. You can also see all three layers contacting the carotid sheath.

One useful way of classifying the neck spaces is in their relationship to the hyoid bone. The more serious infections involve the entire neck and extend into the mediastinum. These include, from anterior to posterior, the retropharyngeal, the danger space, and the prevertebral. Laterally you have the visceral vascular or carotid sheath. Superior to the thyroid is the bulk of the spaces. They include the parapharyngeal, submandibular, submental, parotid, masticator, peritonsillar, and temporal. Inferior to the thyroid are the pretracheal and suprasternal spaces

The retropharyngeal space is a common location for deep space neck infections. Its borders include anteriorly, the pharyngeal constrictors, and posteriorly, the alar fascia. Laterally it is bound by the parapharyngeal space and carotid sheaths. It is a space that extends the length of the neck from the skull base to the mediastinum. The reason for the bulge being off midline with this type of infection is that there is a midline raphe. On either side of this are the nodes of Rouviere, which tend to spontaneously regress around age 5. The areas that drain to these nodes include the nose, nasopharynx, paranasal sinuses, oropharynx, and middle ear. It is thought that the nodes are the source of abscesses in the pediatric age group.

A paper by Grisaru-Soen showed that 80% of retropharyngeal abscesses occur before age 5 with a slight male predilection. When an adult gets an infection it is generally secondary to trauma

This is an axial CT of a patient I saw at TCH who had a retropharyngeal abscess, but hers was actually secondary to a foreign body ingestion which lacerated the posterior pharynx.

The danger space is an area located between the retropharyngeal space and the prevertebral space with the alar fascia as the anterior border and the prevertebral fascia as the posterior border. And just as the retropharyngeal space anterior to it and the prevertebral space posteriorly, it extends from the base of the skull to the mediastinum. Infections in this area are difficult to cause as there are no lymph nodes. Infections generally result from a posterior rupture of a retropharyngeal abscess or from trauma.

The prevertebral space is formed from the prevertebral fascia anteriorly and the vertebral bodies posteriorly. Infections in this space are generally a result of an infection of the vertebral body, especially tuberculosis. However, other causes include trauma, which can include a traumatic intubation, or cervical instrumentation from our neurosurgery or orthopedic colleagues. Infections generally cause midline edema, which distinguishes them from retropharyngeal infections, which are generally off of midline. Of note, Patel published a case study showing a prevertebral abscess 6 weeks following a routine tonsillectomy. Here is the CT from our case showing the prevertebral phlegmon. Again, you can see it in direct contact with the vertebral body.

The carotid sheath is again, made up of contributions from all three deep cervical fascial planes, which allows infections from other spaces to easily spread into this space and extend into the mediastinum. Here is a CT showing a peritonsillar abscess and the arrow is pointing to a jugular vein thrombophlebitis with an intramural thrombus.

The parapharyngeal space is also known as the pharyngomaxillary or lateral pharyngeal space. It is shaped as an inverted cone with the skull base forming the base and the greater cornu of the hyoid forming the apex. Medially it is bounded by the visceral deep cervical fascia, laterally by the superficial layer of deep cervical fascia, anteriorly by the pterygoid mandibular raphe, and posteriorly by the prevertebral fascia. The styloid process penetrates the space and divides it into a pre and post styloid space. It does communicate with the retropharyngeal space and distinguishing an infection between the two can often be difficult. Here is a CT demonstrating a parapharyngeal abscess.

The submandibular and submental spaces are separated by the anterior belly of the digastric, but freely communicate with each other. They are located between the floor of the mouth and the superficial layer of deep cervical fascia, with the non compressible mandible forming the anterior and lateral borders. Infections are generally secondary to odontogenic etiology. Teeth infections anterior to the oblique line of the mandible, which corresponds to the first molar, generally cause infections in the submental space first, whereas infections posteriorly cause infections of the submandibular space.

Ludwig’s angina, which is named after Wilhelm Friedrich von Ludwig who was the first to describe it in 1836, is caused by swelling in the floor of the mouth. As the swelling worsens the tongue is displaced posteriorly, which can eventually lead to suffocation and death. Other than odontogenic infections, other sources of infections of the submandibular/submental spaces include following frenulectomy, oral lacerations, sialadenitis, mandibular fractures, and even an infected lymphangioma. Here is another TCH CT showing a submental abscess, and one showing a submandibular phlegmon.

The peritonsillar space is not actually a deep space of the neck, but infections here are quite common and can spread into the parapharyngeal area which makes it worth mentioning. This space is formed between the superior pharyngeal constrictor and the tonsillar capsule. Anteriorly and posteriorly it is bounded by the palatoglossus and palatopharyngeus, respectively. Although it is something we commonly see, its presentation can be similar to a parapharyngeal abscess, which warrants careful scrutiny for an otherwise routine ER consult. Here is a CT showing a right peritonsillar abscess.

The anterior visceral space or pretracheal space extends from the thyroid cartilage superiorly to the superior mediastinum at the level of the 4th thoracic vertebrae. Anteriorly it is limited by the strap muscles and visceral fascia.

As the name suggests, the suprasternal space is located just above the sternum, between the two heads of the sternocleidomastoid muscles. It is formed from the visceral fascia splitting. Its contents include a lymph node and a vein that connects to the anterior jugular veins.

So how does one go about recognizing that a patient has an infection of the deep spaces of the neck? After reviewing multiple studies regarding the presentation, several common themes were seen. As you can see in this chart by Chang, fever was the most common finding, followed by odynophagia and a neck mass. Another study compared its findings with three other papers regarding the presentation of deep space neck infections and found the most common findings to be fever, neck mass and lymphadenopathy, and odynophagia. And these findings remained consistent in Grisaru-Soen’s paper, showing fever and neck pain to be the most common symptom and lymphadenopathy and limited neck range of motion to be the most common signs.

Once the patient presents, what are some findings in the history you should attempt to elicit to determine the etiology? As previously mentioned, odontogenic sources remain the most common identifiable source, with recent upper respiratory tract infections, suppurative lymphadenitis, and sialolithiasis also remaining prominent. Other less common sources include parotitis, otogenic, trauma, foreign body ingestion, HIV/AIDs, and tuberculosis.

A retrospective study of 210 cases by Parhiscar also showed odontogenic sources as the predominant etiology, with IV drug abuse and pharyngotonsillitis a distant second and third. Hasegawa went on to show that being a diabetic or being a male are independent risk factors that tend to worsen deep space neck infections.

In addition to the history and physical, several imaging modalities have been tested to determine efficacy in diagnosing deep space neck infections. Coulthard showed that lateral radiographs have an 88 percent sensitivity. Findings to look for include:

  • Increased prevertebral soft tissue thickness of >7mm in the retropharyngeal area, or
  • increased soft tissue thickness of >14mm for children and >22mm for adults in the retrotracheal area
  • Presence of air in the prevertebral soft tissues
  • Loss of normal lordotic curvature of the spine
  • Presence of a foreign body
  • Displacement or loss of the prevertebral fat line

Lazor tested the efficacy of CT and showed they had an 88-90% sensitivity but only a 61% specificity, with both a moderate false positive and false negative rate. Smith managed to increase the specificity of CT to 75% if surgery was undertaken with 24 hours of the scan. However, what this goes to show is that we should rely on our clinical judgment based on the history and physical and not just on radiographic findings. Of course, the radiographs can help direct our surgical intervention.

So what organisms should we be covering for when a patient comes in with a deep space neck infection? In 1995, the largest group was gram negatives and anaerobes followed up staph aureus. Other causes included Klebsiella and group A strep. A study from 2001 shows streptococcus viridans, the source of most dental caries, to be the most common cause of abscesses followed by staph epidermidis and aureus and the anaerobe bacteroides.

So how does one go about treating deep space neck infections? The first thing to do is secure the airway, if needed. Then the decision comes down to surgery vs. medical therapy. The old adage was that these required surgical drainage, but several recent studies have provided us with other options.

A retrospective study from Mayor in 2001 consisted of 31 patients who were all treated with IV antibiotics only: either Cefotaxime plus flagyl, Augmentin, or Clindamycin. They also received aggressive hydration and high dose methylprednisolone. Only 3 of the 31 patients required eventual surgical drainage for failure to improve within 48 hours. Of note though, 4 patients had spontaneous drainage into the oral pharynx, but no complications arose. The mean hospital stay was about 8 days, with three patients requiring a 20 day stay.

Here is a recent retrospective study over 11 years of pediatric patients with either retropharyngeal or parapharyngeal abscesses. The study showed that, of the 39 patients, 48% were treated with IV antibiotics and surgery but the remaining patients were treated with IV antibiotics alone. The study showed no significant differences in length of hospital stay and neither group had a death. Some notable differences between the groups showed that younger patients, those who had not been on an extended course of previous antibiotics, and those with a higher white count tended to require surgical drainage. The author’s conclusion was that if there is no airway compromise, then consider IV antibiotics for 48 hours to evaluate for clinical improvement before deciding on surgery.

Boscolo-Rizzo performed a similar study, but in the adult population. In this study, 30% underwent immediate surgery upon presentation as a result of the size and proximity to the airway, evidence of mediastinitis, pneumonia, or jugular venous thrombosis. Of the remaining patient, 22.5% failed to improve on IV antibiotics and underwent delayed surgical drainage; however, none of these patients developed any life-threatening complications. And, the remainder, 47.5%, were cured on antibiotics alone, using either Clindamycin, Augmentin, or a combination of a third generation cephalosporin plus flagyl. Diabetes was a predictor for failure with conservative management and all diabetics required surgical drainage. The mean hospital stay was about 12 days with those with diabetes, those requiring surgery, and those with multiple neck spaces requiring a statistically significant longer stay.

Despite advancements in medical therapy, several findings are consistent with the requirement for surgical drainage. These include: airway compromise, a septic patient, diabetes mellitus, a descending infection, failure to improve within 48 hours of IV antibiotics, an abscess larger than 3 cm, and if either the danger space or multiple spaces involved.

So what are the surgical options? The goal of the surgery is to get to the abscess through the shortest and safest route possible. Areas amenable to an intraoral approach include the retropharyngeal space, if the infection is confined medial to the great vessels; sublingual space (but stay medial to avoid major neurovascular structures; and, peritonsillar space. The remaining areas can be drained by the external approach. The posterior approach is more desirable if possible, as the incision is posterior to the sternocleidomastoid and the major vascular structures of the neck can be avoided.

However, if an anterior approach is required, a transverse incision is made along the anterior border of the sternocleidomastoid muscle at the desired level between the hyoid bone and the sternum. The sternocleidomastoid muscle and carotid sheath are retracted laterally, and the thyroid gland and superior thyroid vessels and superior laryngeal nerve are retracted medially, exposing the abscess generally at the level of the hypopharynx. The middle thyroid vein, inferior thyroid artery, and omohyoid muscle may be sectioned as needed. The abscess is opened between the carotid sheath which lies laterally, and the inferior constrictor muscles, which lie medially, by using a blunt closed clamp that is thrust into the abscess and then opened by spreading the jaws of the clamp. If the abscess has extended down into the neck, the dissection is extended down along the carotid sheath to the sternum, exposing the trachea and esophagus. A finger is inserted into the mediastinum along the esophagus and a drain is left in place. If the infection has spread below the level of the clavicle into the chest, drainage by external thoracotomy may be necessary.

Here are two algorithms for managing patients who present with deep space neck infections. The more recent of the two shows that even if there is a small abscess, you can continue to watch for 48 hours with IV antibiotics before proceeding with surgery, assuming there are no signs of respiratory distress.

Here is a summary slide showing how all of the spaces can communicate with each other.

In summary, we reviewed a case of a patient with a prevertebral phlegmon, went over some of the history of the cervical fascia as well as relevant anatomy, and reviewed some of the modern treatment options for deep space neck infections.

Case Presentation

A 17-year-old female with a remote history of a tonsillectomy and ESS x 2 who presented to the TCH ER with a 9 day history of odynophagia. Six days prior to presentation the pain peaked and the mother treated the patient symptomatically with Advil and the pain improved but did not resolve. Four days prior to presentation the patient developed a “head cold” which was treated with Afrin, Nasonex, and nasal saline which improved. Two days prior to presentation the odynophagia began to worsen and the patient began to have significant left ear pain. At that time she was seen in the TCH ER and given Amoxil for a presumed ear infection. The patient vomited up the antibiotic and presented back to the TCH ER for a temperature of 101.5 and inability to tolerate PO.

  • VS: Tc: 98.7 HR: 114 BP: 138/66
  • Gen: No acute distress, no drooling
  • Head: normocephalic, atraumatic
  • Ears: minimal left preauricular tenderness, external auditory canals clear, tympanic membranes intact, no evidence of infection
  • Nose: no rhinorrhea
  • Oral Cavity/Pharynx: Minimal trismus, absent tonsils, no uvular deviation, minimal fullness of left posterior oropharynx but no erythema
  • Neck: supple, limited range of motion to the left, tenderness in left level II
  • Prevertebral Phlegmon

Patient was admitted to the pediatric service for IV antibiotics. Patient improved symptomatically and was discharged home on hospital day 3. Neurosurgery was consulted given the location and recommended IV antibiotics.

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