Exam 3 - More Cervical Congenital and Developmental Variants

What are the 4 classic features of block vertebrae? But not all are required

Rudimentary disc

Smotth concave vertebral body margins (wasp waist vertebra)

Comibned vertebra may be of normal height, short or tall

Large foreman seen on lateral view

How can you evaluate the POSSIBLE impact of block vertebra?

Typically minimal impact

Can have have hyper or hypo mobility around region of block vertebra

Etiology of block vertebra

Failure of somite segmentation

Block vertebra is most common at what levels?

C5/C6

C2/C3

L4/L5

What is something that you can see on the posterior aspect of the patient with block vertebra?

Non-segmentation of the posterior elements as welll

Congenital block vertebra has what type of disc

Rudimentary (remnant)

Acquired block vertebra has what type of disc

Obliterated (obscured/hazy) disc

What type of anterior vertebral body margins does congenital block vertebra have?

Smooth concave

What type of anterior vertebral body margins does acquired block vertebra have?

Flat/squared

The vertebral body height of congenital block vertebra may be?

Normal height, short or tall

The vertebral body height of acquired block vertebra may be?

NO CHANGE in the height

The foramen of congenital block vertebra are?

Large on lateral view

The foramen of acquired block vertebra are?

NO CHANGE in size

How can a block vertebra be acquired?

Surgical

Post injury

How can block vertebra be acquired via surgery?

Used to be bone growth in disc, typically from ilium (autograft)

Now more common to us metal

Vertebral body height may be___________ because of infection

Decreased

What is ACDF and ACCF? What is more common?

ACDF= anterior cervical discectomy and fusion (more common)

ACCF= anterior cervical corpectomy and fusion

Multiple blocked vertebra over many "segments" is called

Clipofilic

What is another thing to look for with occipilzation or non-union of the C1 posterior tubercle

Very dense Harrison Ring in C2

What is Kippel-Feil syndrome?

Complex of congenital anomalies

What may Klippel-Feil syndrome include?

Multiple segmentation anomalies of cervical spine

Short webbed neck (pterygium colli)

Low posterior hairline

Reduced cervical range of motion ( more than 1/2 of patients)

What are some associated conditions of Klippel-Feils syndrome

Renal anomalies

Hearing loss, possibly deafness

Arnold Chiari and/or syringomyelia (basilar invagnation >3mm)

Sprengel deformity

What is something that can be seen on a PA or AP cervical xray of someone with klippel-feils syndrome>

Dark spots/line in the middle indicating neural arches didnt come together (spina bifida occulta)

What is something that not all Klippel-Feil patients have but still may occur?

Omovertebra

What is an Omovertebra

Extra bone that goes from cervical spine to medial border of the scapula

What are some other names for posterior ponticle at C1?

Arcuate foramen

Foramen accurate Atlantis

Poniculus posticus

Kimmerle anomly

What is a frequently encountered normal variant of the atlas and is easily appreciated on a lateral film?

Posterior ponticle

Posterior ponticle occurs in _________ of people and is more common in __________

8%

Females

The posterio ponticle develops by ____________________________ between the posterior aspect of the lateral mass and the posterior arch

Calcification of the posterior Atlanta-occipital membrane

What pass through the posterior ponticle

Atlantic portion (V3) of the vertebral arteries

Radiographic features of the posterior ponticle

Complete or incomplete bony arch is seen overt the posterosupeior aspect of the atlas on lateral projection

The posterior ponticle can be?

Complete or incomplete

Unilateral or bilateral

What is a bony extension originating from the transverse process of C1 upward to the skull base

Epitransverse process

An epitransverse process can form what?

An extra articulation with the occiput

What is a variant of the occipital bone where an enlarged bony process extends causally from the paracondylar region towards the transvserse process of the atlas

Paracondylar process

An epitransverse process and paracondylar process are both ______________ of bone growth

Hyperplasia

A large amount of epitransverse or paracondylar processes are?

Asymptomatic

If an epitransverse or paracondylar process are symptomatic, what would they be?

Occipitocervical pain

Functional limitations of head and neck movement or even torticollis

Clinical significance of epitransverse process

May create lateral head tilt

May affect adjusting technique (effectively results in fusion of C1 to occiput)

How would you best see an epitransverse process?

CT scan is the best way

Or well positioned APOM

What is the failure of union of the secondary ossification found at the tip of the dens?

Os terminale

What are some other names for os terminale?

Ossiculum terminale

Bergman ossicle

When does an os terminale appear?

Between ages 3-6

An os terminale is not considered an anomaly unless?

It persists after the age of 12

TRUE or FALSE

Os terminale is not associated with instability

TRUE

What is the difference between an Os Terminale and just an open growth plate in a young person

Os terminale has the tip fully separate and away from the dens

Open growth plate the pieces are still close together

What could cause an allusion fracture of the tip of the dens?

Apical and Alar ligaments attach at the tip of the Dens

What is it when there is a fracture of of the odontoid synchondrosis (growth plate), most likely during early childhood that goes unrecognized at the time?

Os Odontoideum

How can the anterior tubercle of C1 give hints towards Os Odontoideum?

It typically should be flat or concave but with Os Odontoideum it can be more round cause it had no dens to articulate with

Describe the "Molding Defect" (hypertrophy of the atlas anterior tubercle)

Change in shape of the atlas anterior tubercle that results in long standing altered articulation with the den of C2

When it occurs more round than normal

What is something that can occur with Os Odontoideum? Why?

Spinal canal stenosis

From anterior slippage of atlas cause of nothing for the transverse ligament to attach to with no Dens there

What is something else on C2 that can point towards Os Odontoideum?

A very round and cortical dense Harrison Ring

What is something that can point you towards NOT diagnosing Os Odontoideum when it's actually a fracture?

There is a lack of cortication and the odontoid is of normal size and shape

TRUE or FALSE

A fracture of the dens that still has cortication and normally shaped has the possibility to not be Os Odontoideum

TRUE

What is the clinical significance of os Odontoideum?

Possibly none

Neck, shoulder pain, headaches, torticollis

Transient to frequent neurological sympomts

Increased C1-C2 motion

Why could you get increased C1-C2 motion with Os Odontoideum?

Transverse ligament can't hold C1 to the dens of C2

What are some transient to frequent neurological symptoms that could occur with os Odontoideum?

Paresthesia of neck and upper extremities

Lower limb weakness, gait alterations

Increased C1-C2 motion with os Odontoideum can lead to?

Ventral artery occlusion

Ischemia and brainstem

-seizures

-syncope

-vertigo

-visual changes

-sudden death

Why is the "significance" of os Odontoideum so varied? Talk in terms of motion and trauma

Motion= the anatomy may not move as much in some compared to others

Trauma= may have no symptoms prior to trauma to "set it loose"

What type of odontoid fractures involve avulsion off the tip of the odontoid?

Type I fractures

What type of odontoid fractures occur at the odontoid base (at the synchondrosis)

Type II fractures

What type of odontoid fractures extend into the C2 body and typically involve the superior C2 facet joints

Type III fractures

Which features can be assessed to aid in deterring acute from healed odontoid fractures?

MRI can show marrow edema on new fractures

Shape of bone

Cortication or lack of cortication

Most Os Odontoideum are a result of?

An old un-united odontoid fracture (pediatric undiagnosed fracture)

Most old in-united odontoid fractures are?

Not an an Os Odontoideum

Treatment options for os Odontoideum

Vary from no therapy to surgical treatment depending on symptoms and atlantoaxial instability

What is recommended for asymptomatic Os Odontoideum patients with no evidence of C1-C2 instability?

Avoidance of all contact sports is recommended

What is recommended for asymptomatic Os Odontoideum patients with atlantoaxial instability? What are the negatives

Surgery

-loss of normal neck rotation as much as 50%

All symptomatic Os Odontoideum patients are candidates for?

Surgical treatment

The treatment strategies for Os Odontoideum can be put in what 4 steps?

1. Determine pathology causing symptoms

2. Define whether atlantoaxial subluxation is reducible or not

3. Decide whether the lesion requires decompression or not

4. Select the surgical option for stabilization and fusion