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157 Cards in this Set

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What was the perivertebral space previously called?
The prevertebral space
Why was the name changed?
Because only a portion of the prevertebral space is indeed prevertebral (i.e. in front of the vertebrae).
What are the different portions of the perivertebral space?
The perivertebral space has a prevertebral portion, and two paraspinal portions.
What fascial layer forms the perivertebral space?
The deep layer of deep cervical fascia
How does this fascia run?
The deep layer of deep cervical fascial forms the prevertebral portion of the perivertebral space as it arches anteriorly from the transverse process to the opposite transverse process.


This fascia then continues posteriorly to completely enclose the paraspinal muscles, and attaches to the nuchal ligament of the spinous process of the vertebral body. This is the paraspinal portion of the perivertebral space.
In essence, what does the deep layer of deep cervical fascia do?
It completely encircles the perivertebral space, sectioning it off into three separate portions.
What is the craniocaudal extent of the perivertebral space?
Skull base (clivus) to T4
What do some anatomists believe about the perivertebral space?
That it extends in some form all the way down to the coccyx.
In the suprahyoid neck, what is contained within the prevertebral portion of the perivertebral space?
Prevertebral muscles


Vertebral artery and vein


Vertebral body
In the suprahyoid neck, what is contained within the paraspinal portion of the perivertebral space?
Paraspinal muscles



Posterior elements of vertebrae



Fat
In the infrahyoid neck, what is contained within the prevertebral portion of the perivertebral space?
Pervertebral muscles


Scalene muscles


Phrenic nerve


Roots of the brachial plexus


Vertebral body
In the infrahyoid neck, what is contained within the paraspinal portion of the perivertebral space?
Paraspinal muscles



Posterior elements of vertebrae



Fat
We frequently are referring to prevertebral muscles. What are the more specific names of some of these?
Longus capitis


Longus colli
Where does disease that begins in the perivertebral space usually spread?
Usually spreads into deeper recesses within the perivertebral space, like the epidural space.
Why is that?
Because the deep layer of deep cervical fascia is very very tenacious, and does not usually allow spread of disease through it.
What is another name for the deep layer of deep cervical fascia that surgeons use?
Carpet. They call it that because it appears like a smooth, flat, carpetlike surface when they approach it surgically.
What structure(s) pass through the deep layer of deep cervical fascia?
Only the roots of the brachial plexus.
How can the roots of the brachial plexus be identified on imaging?
They are laterally extending structures which pass directly posterior to the anterior scalene muscle on their way to pierce the deep layer of deep cervical fascia.
Once they pierce the deep layer of deep cervical fascia, where are the roots located?
They are now within the posterior cervical space
What are the different scalene muscles?
Anterior


Middle



Posterior
What space is directly anterior to the prevertebral portion of the perivertebral space?
The retropharyngeal/danger space
When does disease from the RPS spread into the prevertebral portion of the perivertebral space?
Only in the most extreme cases
What space is anterolateral to the pervertebral portion of the perivertebral space?
Carotid space
What space is directly lateral to the paraspinal portion of the perivertebral space?
Posterior cervical space
What space is directly posterior to the paraspinal portion of the perivertebral space?
Nothing. Just skin and the outside world.
What do clinicians sometimes confuse on their exam?
Thinking that a normal (i.e. transverse process) or abnormal mass in the paraspinal portion of the perivertebral space is in the posterior cervical space.
When features allow a mass to be considered primary to the prevertebral portion of the perivertebral space?
1) The center of the mass is within the prevertebral muscles or vertebral body.


.........AND/OR..........



2) The mass lifts the prevertebral muscles anteriorly.
In most cases, what does the anterior displacement of the prevertebral muscles by a mass in the prevertebral portion of the perivertebral space distinguish it from?
A mass in the retropharyngeal space
What features define a lesion as primary to the paraspinal portion of the perivertebral space?
1) The center of the mass is within the substance of the paraspinal musculature



........AND/OR.........




2) The mass bows the fat of the posterior cervical space away from the posterior elements of the spine.
In the case of most lesions of the perivertebral space, what is abnormal at the time of imaging?
The vertebral body.
Why?
Because the vast majority of lesions of the perivertebral space originate from the vertebral body.
What are these most typical lesions?
Infection and metastases
Clarification: What does a mass pushing on the paraspinal muscles do?
It deviates (anteriorly or posteriorly, depending if lesion is in RPS or PVS) but also flattens the prevertebral muscles
When a lesion fills the prevertebral portion of the perivertebral space, where does it often decompress or escape to?
The epidural space.
How does it get to the epidural space?
It moves in from the lateral recess
What else does it have the potential to cause much harm to?
The vertebral artery
In the infrahyoid neck, what other structures can be invaded by the mass in the prevertebral portion of the perivertebral space?
The brachial plexus roots, as they head laterally towards the scalene muscles.
In the paraspinal portion of the perivertebral space, what does the mass usually do?
If it arises in the bone, it displaces the paraspinal muscles away from the spine.



If it arises in the muscles themselves, then there will be irregularity of the muscles, blurring of fat planes, and possibly lateral deviation of the fat of the posterior cervical space.
What sometimes occurs with an infiltrative mass (infection or malignancy) of the perivertebral space?
It can traverse the fascial separation between the prevertebral and paraspinal portions of the space. But it will still remain confined by the deep layer of deep cervical fascia.
What is the first question to be asked once a mass is placed within the perivertebral space?
Is there epidural extension.
Which more commonly occurs first: Epidural extension or superficial extension through the deep layer of deep cervical fascia?
Epidural extension usually occurs LONG BEFORE a mass invades outside the bounds of the perivertebral space.
What is the categorical differential diagnosis for lesions of the perivertebral space?
1) Vascular


2) Inflammatory



3) Pseudomass



4) Benign tumor



5) Malignant tumor
What are the vascular lesions occuring within the perivertebral space?
Vertebral artery dissection
What is the clinical setting?
Posttraumatic neck pain


A variety of associated neurologic symptoms
What happens if the distal vertebral artery is involved with thrombosis?
PICA may be involved
What can occur if PICA is involved?
Lateral medullary syndrome
What is the eponym for lateral medullary syndrome?
Wallenburg syndrome
What are the MRI findings in vertebral artery dissection?
Crescentic region of high signal on T1W images within the wall of the affected artery
What will be seen in more severe cases?
Absence of flow
What may be seen if disease extends to the PICA origin?
Lateral medullary


AND


Inferior cerebellar



INFARCTION
What are inflammatory lesions of the perivertebral space?
Vertebral body osteomyelitis with associated perivertebral space abscess
What are the clinical indications of perivertebral space abscess?
Fever, neck pain, and tenderness
What is a sign of impending catastrophe?
Development of paresis
How severe can the paresis be?
May be quadriparesis
What are these neurological symptoms caused by?
Pus gaining access to the epidural space and compressing the cord
What is a common cause of vertebral body infection in the urban setting?
Tuberculosis
What is the most common cause of pyogenic vertebral body infection?
Staph
What is the second most common cause?
Enterobacter
How do most cases of vertebral osteomyelitis get into the bone?
Bacteremia
Why are the vertebral bodies especially susceptible to osteomyelitis?
The bone marrow acts as a filter for pathogens
What are the typical radiographic features in vertebral body osteomyelitis/diskitis?
Destruction of adjacent vertebral bodies and intervening disk space
What percentage of cases of vertebral osteomyelitis/diskitis have involvement of the perivertebral space (i.e. perivertebral space abscess)?
20%
What does this appear as?
Abscess cavity/fluid in the adjacent perivertebral space
What happens when the osteomyelitis spreads posteriorly?
Epidural pus, with possible cord compression
What occasionally occurs in infection of the perivertebral space, when the prevertebral portion is involved.
Extension through the deep layer of deep cervical fascia into the retropharyngeal space
What is the modality of choice for evaluation of suspected osteomyelitis/diskitis?
Contrast enhanced MRI
Why?
Because of sensitivity of MRI to:

1) Epidural disease


2) Cord compression
What is the most common pseudomass of the perivertebral space?
1) Vertebral body osteophyte
What are the other pseudomasses of the perivertebral space?
2) Anterior disk herniation


3) Levator scapulae hypertrophy


4) Large or asymmetric transverse process


5) Cervical rib


6) Hypertrophic facet joint
What is the clinical presentation of anterior vertebral body osteophyte?
Usually incidentally detected on plain films.
What is clinical presentation of anterior vertebral body osteophyte when very large?
Dysphagia
What is clinical history in most patients with anterior disk herniation?
History of prior severe head trauma
What is the finding of anterior disk herniation on imaging?
Disk material protruding anteriorly into the prevertebral portion of the perivertebral space
What is the cause of hypertrophic levator scapulae?
Spinal accessory nerve injury
What does injury to the spinal accessory nerve cause?
Atrophy of the sternocleidomastoid and trapezius
So why is this associated with hypertrophy of the levator scapulae?
The levator scapulae tries to take up the slack from the other two denervated muscles, providing lift of the shoulder that normally comes from the other two muscles.


In doing so, it hypertrophies.
In what clinical setting does spinal accessory nerve injury most commonly occur?
Neck dissection
What is the clinical setting by which a prominent transverse process is detected by the referring clinician?
Palpates an asymptomatic deep mass
At what level is this "mass" most commonly palpated?
At the level of the parotid gland. The clinician is concerned about a mass deep to the parotid.
What is seen on imaging when the referring physician palpates a prominent transverse process?
Nothing.
How is the diagnosis made, then.
There is no mass found on imaging, and the imager gently suggests to the referring clinician that what he is feeling may actually be a transverse process.
When the "mass" is palpated deep to the parotid, at what level is this transverse process?
C2
What percentage of people have cervical ribs?
1%
What is the clinical presentation of cervical rib?
Asymptomatic deep mass, usually in low cervical region
What do some patients with cervical ribs develop?
Thoracic outlet syndrome
What percent of patients with cervical rib develop throracic outlet syndrome?
10%
Imaging features of cervical rib?
No mass is identified. The cervical rib is found, and the referring clinician is informed of the finding.
From what tissues do benign tumors of the perivertebral space originate?
Just think about what is there. The main constituents are NERVES and BONES. Muscles too, but there are not so many benign tumors of muscle.
What are benign tumors of the perivertebral space?
1) Nerve sheath tumors


2) Benign tumors of the vertebrae
Where do schwannomas of the perivertebral space occur?
Again, think of the primary nervous structures within the perivertebral space:


1) Cervical roots


2) Brachial plexus
What are the characteristics of schwannoma in the perivertebral space?
Painless, slow growing mass
So how do they come to clinical attention?
They are palpated
Where are they usually palpated?
1) Lateral neck


2) Retroclavicular area


3) Axillary apex
In what clinical setting can schwannoma be multiple?
NF II
Where can schwannoma be found on imaging?
1) Anywhere along the course of spinal roots

--epidural space
--neural foramen


..........OR..........



2) Anywhere along the course of the brachial plexus:

--from the the spinal nerves contributing to the plexus,

--to the gap between anterior and middle scalenes,

--to the posterior cervical space,

--to the axillary apex.
What can schwannoma look like on coronal images when it involves the neural foramen?
Dumbell lesion
What does schwannoma do to the adjacent bone at the neural foramen?
Smoothly enlarges it
What is the MRI appearance of schwannoma?
-Enhancement-
Uniformly enhancing
What is the MRI appearance of schwannoma?
-Borders-
Well circumscribed
What is the MRI appearance of schwannoma?
-Shape-
Fusiform
What imaging plane best demonstrates the fusiform appearance of schwannoma of the brachial plexus?
Coronal
What are neurofibromas associated with
NF 1
What is the other name for NF 1?
von Recklinghausen syndrome
What age group is most likely to have solitary neurofibromas?
Young (20-30)
So what should be done when a neurofibroma is found in an older patient?
Look for other neurofibromas
What are the symptoms of neurofibromas?
Depend on the nerve involved
What are the imaging features of neurofibroma?
Same as for schwannoma
What is the one imaging difference?
May have low density appearance on CT
What is the low density appearance due to?
Fatty degeneration
What are the benign bony tumors occuring in the vertebrae?
1) Aneurysmal bone cyst



2) Giant cell tumor



3) Osteoblastoma
What part of the vertebrae does aneurysmal bone cyst involve?
Posterior elements
What is the typical clinical presentation of cervical vertebral aneurysmal bone cyst?
Posterolateral neck swelling
What age group is most commonly affected with cervical vertebral aneurysmal bone cyst?
5 -- 20 years old
What percentage of patients with cervical vertebral aneurysmal bone cyst are within this age range?
70%
What percentage of patients with cervical vertebral aneurysmal bone cyst had a preexisting osseous lesion before formation of the ABC?
50%
What may be seen within the osseous lesion?
Multicystic lesion, which may have fluid/fluid levels
What do the fluid fluid levels represent?
Layering of blood
What is typical age for vertebral giant cell tumor?
20 -- 40 years
What percentage of patients with vertebral giant cell tumor fall into this range?
70%
What is the clinical presenting sign?
Symptoms of cord or nerve root compression


Or, bony expansion detected on plain film
Where are vertebral giant cell tumors found?
Vertebral bodies


Sacrum
Where are vertebral giant cell tumors rarely found?
Posterior elements
What are the imaging features of vertebral giant cell tumors?
Lytic lesion


(+/-) Narrow zone of transition


No sclerotic margin
What percentage of patients with vertebral giant cell tumors have an associated soft tissue component?
25%
What is the common age group for verebral osteoblastoma?
20 -- 40
Where are vertebral osteoblastomas located?
Posterior elements
What is the clinical presentation of vertebral osteoblastoma?
Posterolateral neck swelling
What are the imaging findings of osteoblastoma?
Expansile mass of the posterior elements


Lucent or sclerotic
What does the histology of osteoblastoma show?
Same as osteoid osteoma
What is the difference between osteoid osteoma and osteoblastoma, then?
Osteoblastoma is greater than 2 cm in diameter
What are the common malignant tumors of the perivertebral space?
1) Chordoma


2) Vertebral body or epidural metastasis
What are the other malignant tumors of the perivertebral space?
3) Primary malignant tumor of the vertebra



4) NHL



5) Direct invasion of SCCa
Where does chordoma occur?
At the ends of the previous neural tube:

Sacrum


Clivus


Lower lumbar spine


Upper cervical spine
What is the clinical presentation of clival chordoma?
Headache, facial pain, nasal stuffiness, progressive cranial nerve malfunction.
What is chordoma pathologically?
Low grade malignant neoplasm


Arises from notochordal cell rests = physalipherous cells
What is the imaging appearance of chordoma?
Destructive clival mass
What does clival chordoma typically involve early on?
Nasopharyngeal perivertebral space
What is a characteristic feature of chordoma?
100% are calcified on CT
What is the modality of choice in evaluating clival chordoma?
MRI

Even though CT demonstrates the calcium better, MRI allows:

1) Delineation of the clivus as the site of tumor origin


2) Demonstration of adjacent neurovascular structures
What are the most common tumors to metastasize to the cervical vertebral bodies?
1) Lung


2) Breast


3) Prostate


4) NHL
What are the radiologic features associated with vertebral metastatic disease?
Vertebral body destruction, in association with a perivertebral space mass.
What else is commonly present and must be looked for carefully?
Epidural extension
What is the modality of choice in evaluation of vertebral mets?
MRI
What are the primary vertebral malignancies?
1) Ewing sarcoma


2) Osteosarcoma
What is the typical age range for Ewings's?
5 -- 25 years
What percentage of patients fall in this age range?
95%
What is the presentation in 1/3 of cases?
Presents symptomatically like an infection
What are the imaging features in Ewing's?

--Zone of transition--
Wide. Aggressive margins.
What are the imaging features in Ewings's?

--Matrix--
Non-matrix producing
What are the imaging features in Ewings's?

--Soft tissue component--
Extensive soft tissue component
How is osteosarcoma differentiated from Ewing's?
Osteoid matrix
What is seen in NHL of the perivertebral space?
Soft tissue mass infiltrating the tissue planes of the involved portion of the perivertebral space
What is the appearance of NHL of the perivertebral space indistinguishable from?
Metastatic disease
What is helpful in distinguishing NHL from metastatic disease?
Clinical history
What is the clinical setting in which direct invasion of SCCa into the perivertebral space occurs?
Known invasive SCCa involving the posterior wall of the nasopharynx, oropharynx, or hypopharynx (pharyngeal mucosal space)
What are the radiologic features of direct invasion of SCCa?
Mass is seen extending from the pharyngeal mucosal space, through the retropharyngeal and danger spaces, through the deep layer of deep cervical fascia, and finally into the perivertebral space.
In direct extension of SCCa into the perivertebral space, when is the vertebral body affected?
Not until very late in the process