Radiology: Spine – revised

– hard to see, thin gray line
– L image: should be smooth line from C2 body and dens, instead there’s a break at L right arrow
– R image: lat. view, can see better

1) Anterior subluxation
2) Simple wedge
3) Unstable wedge
4) Unilateral interfacet dislocation
5) Bilateral interfacet dislocation
6) Flexion teardrop fracture
7) ant atlantoaxial dislocation

U/L jumped facet = AKA “perched facet dislocation”

*Fx involving both pars interarticularis of C2
*Image shows fx at bilat lamina & pedicles, and usually anterolisthesis at C2-C3

*looking for indirect sign, change in lat. masses of C1 arch and the dens (L lat mass is further from dens)
(hard to see on XR –> CT)

IV disc spaces
SP
Pedicles
Alignment
VB height

-in Lumbar Oblique

-Nose = TP Process
-Ear = Superior articular facet
-Eye = Pedicle
-Neck = Pars Interarticularis (look for lucency here)
-Front Leg = Inferior articular facet

Pars Interarticularis #, often assoc. with anterolisthesis
–> young pts <30 y/o, sports/stress-related activity

1: 0 – 25%
2: 25 – 50%
3: 51 – 75%
4: 76 – 100%
5 (Spondyloptosis): >100%

*lumbar pars defect
*stress fx from repetitive injury

-usually B/L
-excess bone
-facet jts trying to stabilize themselves

*FLEXION FRACTURES:*
1) *Compression Fracture*: Anterior part of vertebral body breaks/loses height while posterior part of vertebral body is intact. Usually stable.
2) *Axial Burst Fracture*: Vertebra loses height along both anteriorly & posteriorly

*EXTENSION FRACTURES:*
1) *Extension/distraction (Chance) fracture*: Vertebra is pulled apart (distracted). (AKA seatbelt #)

(ROTATION FRACTURES:)
1)Transverse process fracture: Uncommon; from rotation or extreme lateral bending

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2)Fracture-dislocation Involves bone and/or soft tissue in which vertebra may move off an adjacent vertebra (displaced). Unstable injury.

AKA Compression
-ant VB

magnified view on R
– loss of height ant

*Compression injury to ant. vertebral body and transverse # through post. vertebral body

*Vertical disc herniations through the cartilaginous vertebral body endplates

–> concave endplates (vs. parallel like normal)
-can be just inf., just sup., or both
-smooth remodeling

-SI Joints
-Sacral ALA
-Coccyx

-Sacral Coccygeal angle
-Cortical Integrity
-Pre-Sacral soft tissue

(normal SI jt.)

-not at SI jt
-most are vertical

Evaluation of Bony architecture
(limited evaluation of spinal cord and nerve roots)

saggital view
-CT scan: you see more of the bony and soft tissue structures
-white: bone
-gray: fat, muscles, vessels
-black: air

axial view
– C1: complete ring

saggital view
– the worse the scoliosis, the worse the image (you won’t see all vert. clearly)
– bone & soft tissue windows

bone window L, ST window R

L: midline (can’t see #)
Middle: more lateral, start to see defect
R: lateral #

axial
– much better on CT than xray
– facet jts: obliquely oriented defect/lucency
– pars articularis: horizontally oriented defect/lucency
– spinal canal more flute-like/champagne shape (instead of round) –> widening due to ant. slippage that usually goes along w/pars defect

– CT
– vert. lost height, lots of # lines
looking for:
1) retropulsion of bone (bone fragment extending back into spinal canal)?
2) canal stenosis, esp. in thoracic?
–> MRI imaging

– CT, soft-tissue window, bad canal stenoisis

– usually through-and-through #, or just ant. vert. body (rarely just post. vert. body)
– this example: some post. retropulsion (we’re a bit below the conus hopefully, but some folks have conus at L2 –> MRI)

– flattening of thecal sac –> canal stenosis

– more loss of vert. height
– retropulsion: causing more SC stenosis? Pt may have more Sx’s

1) Osteoporosis (most common)
2) Direct acute trauma in healthy vertebra
3) Neoplasms
– Infiltrative neoplasms
(eg multiple myeloma, lymphoma)
– Metastatic neoplams
(eg prostate, breast, lung)
– Primary bone neoplasm
(hemangiomas, giant cell tumors)

Conservative Management (if they’re simple #’s) for 4-6 wks
-initial and gold standard of treatment
-medical management with or without methods of immobility
-medications (NSAIDS and narcotics)

Complications of medications
-NSAIDS – Gastrointestinal hemorrhage, ulcers
-Narcotics – constipation, nausea, somnolence, addiction

-Most patients with osteoporotic fractures have spontaneous resolution of pain within 4-6 weeks from initial onset, *even without medication!*

– vert. augmentation –> considered if sig. CI’s to pain meds, or are still in sig. pain/compromise to ADL after 6 wks

-Procedures used for palliation of pain related to vertebral compression fractures

-Types of Vertebral Augmentation
1) Percutaneous Vertebroplasty (PV)
2) Balloon-assisted Kyphoplasty

-Both involve injection of an acrylic cement under local anesthesia and either fluoroscopic guidance (or, less commonly, CT guidance) to control the pain of vertebral fractures

-85-90% patients have rapid pain relief

1) Pain localized to a fracture or tumor
2) Pain refractory to medical management
– medical management for at least 6-12 weeks
3) Fracture less than 12 months old
4) Contraindications to medications or requirement for IV narcotics and hospital admission

1) Fracture extending to posterior vertebral cortex retropulsed fragment
2) Cord compression
3) Radiculopathy
4) Fever and/or sepsis
5) Coagulopathy (bleeding disorder)
–> take-home: conservative tx HAS TO BE DONE 1st!!!

-Injection of low-viscosity acrylic cement (methylmethacrylate) directly into vertebral body using a unipedicle or bipedicle needles
-Typically perfomed in an O/P setting
-Objective: treatment of pain (preventing painful motion of vertebral body fragments moving against one another); presence of cement also stabilizes vertebra from suffering another fracture.

-DOES NOT RESTORE VERTEBRAL BODY HEIGHT
-may be done prophylactically for “at-risk” vertebra between two other abnormal vertebrae

take-home –> cement injected, for pain and not height

Low Complication Rate (1-3.9%)

Acute Complications:
-Cement leak (symptomatic or asymptomatic)
-Cement pulmonary embolism (asymptomatic or symptomatic)
-Bleeding/hematoma
-Infection
-Neurological deficiet (transient or permanent)

Delayed Complications:
-New fracture at other levels?
–> diminished compliance of vertebra b/c of cement places remaining vertebral bodies at higher risk for fx?
OR
–> “Clustering of fractures” as natural history of osteoporosis

– Inflation of one or two intravertebral body high pressure balloon tamps to create a cavity in which high-viscosity arcylic cement is then injected

– Performed via unipedicle (1 balloon) or bipedicle (2 balloons)

– Margins of the cavity are lined by the displaced, fragmented trabeculae.

– Usually requires hospitalization (as opposed to Perc Vertebroplasty)
–> pain relief AND restores height loss

-Because the injection of acrylic under pressure is likely to pass through the fracture into the spinal canal, a posterior cortical defect is considered a relative contraindication for vertebroplasty

-Vertebroplasty also is contraindicated in cases involving a bone infection such as diskitis with osteomyelitis.

Need CT delineation of soft tissue structures within spinal canal for:
1) Patient who cannot get MRI
2) Patient with surgical hardware in spine which obscures visualization of spinal canal on MRI and CT scan.

EG: Evaluation for degree of canal stenosis and/or cord compression, disc herniation, arachnoiditis

Injection of contrast material into thecal sac under flouroscopic guidance with subsequent CT imaging of the spine

-Bleeding disorder (elevated PTT/INR)
-Less frequently performed due to the invasive nature of the test and associated risks.

1) DEGENERATIVE DISEASE
-Disc herniation
-Spinal stenosis and Cord compression
-Nerve Root Impingement (Radiculopathy/Sciatica)

2) OSSEOUS AND EXTRAOSSEOUS INFECTION
-Discitis/Osteomyelitis
-Epidural and Paraspinal Abscess

3) NEOPLASM
-Osseous Metastasis
-Spinal cord, epidural or nerve root mass

4) DEMYELINATING/INFLAMMATORY DISEASES:
-Eg. Multiple sclerosis lesions (cervical & thoracic)

5) TRAUMA
-Acute versus Chronic Fractures
-Epidural/Subdural Hematomas
-Ligamentous rupture

6) POSTOPERATIVE SPINE:
-Recurrent disc herniation versus Postoperative
-Granulation tissue

-No ionizing radiation

Contraindications:
>> Absolute
– Ferromagnetic Aneurysm clip
– Cardiac pacemaker
– Orbital metallic foreign body, cochlear implant, IVC filter

>> Relative
– Metal fragments (depending on location -> soft tissue burn)
– First trimester pregnancy (risks vs. benefits)
– Transcutaneous nerve stimulators
– Severe claustraphobia

-Degenerative Disease
-Lumbar back pain
-Radiculopathy
-Preoperative Planning

-Patient with EGFR <30 (measure of kidney function), contrast is considered contraindicated due to increased risk of Nephrogenic Sytemic Fibrosis (NSF)

– Postoperative spine recurrent back pain evaluation:
>> to see granulation tissue vs. recurrent/new disc herniation
– Metastatic Bone disease (bone and spinal cord)
– Primary Spinal Cord lesions (tumor, demyelinating disease, )
– Spinal Infection (discitis/osteomyelitis, epidural abscess)

typical protocols:

*MRI Cervical Spine*
-T1 weighted images (Sag & Ax)
-T2 weighted images (Sag & Ax)
-STIR (Sag)
-Gradient Echo (Axial) –> bone black, fluid bright, *accentuates bony structures* b/c there’s so much bony path. in C-spine

*MRI Thoracic & Lumbar Spine*
T1 weighted images (Sag & Ax)
T2 weighted images (Sag & Ax)
STIR (Sag)

*Water: T1 hypointense (dark), T2 & STIR hyperintense (white)*
-CSF
-normal disc space
-bone or soft tissue edema
-fluid collections (postoperative seroma, synovial cysts, abscesses)

*Fat: T1 & T2 hyperintense (bright), STIR hypointense (dark)*
-Subcutaneous fat, yellow (fatty) bone marrow,
-“Yellow” (fatty) bone marrow: age-related; degenerative
-Fat-containing lesions (eg Lipoma)

*Normal Bone: T1, T2 & STIR hypointense (dark)*
-Vertebral bodies and posterior elements of spine

*Sclerotic Bone: T1, T2, and STIR markedly hypointense (very dark)*
-Degenerative sclerosis, Sclerotic Metastasis, Calcified ligament or disc

T2 & STIR: fluid bright
– CSF, thecal sacs

STIR: fat dark (“suppressed”)
T2: fat bright

“signal intensity” of the structures in MR
– general rule: disk space should always be darker than vertebral bodies, normal “marrow intensity”, in T1
– as we age, the signal changes (more fat) –> but this rule still applies
– if it’s darker –> abnormal. Tumor? Sclerosis (bone getting denser d/t degen. or malignancy)?

– general rule: disk space will always be bright on T2 & stir (b/c most of the disc is fluid)

– keyhole structures at level of disc space
– contain fat & nerve roots
– want to ensure they’re ~symmetrical w/in their region (C, T, L)
– T1&2: bright signal (fat) surrounding dark signal (nerve root)
– STIR: vessels around nerve root (a little bright), but fat supressed –> STIR not a great view of foramina
–> looking for any encroachment/narrowing (facet arthropathy, disc herniation, etc)

axial view
– can see thecal sac and CE nerve roots (vs. CT imaging)
–> can tell is there’s any compression

through the disc space
– neural foramena: fat (bright) + n. roots (dark)

– moving down through bodies, coming into disc space in middle images
– T2: body is gray, disc space is brighter (fluid)

Cervical spine:
– exiting nerve root at the disc space is from the level below (eg at C5-C6, C6 exiting nerve roots noted; at C7-T1, C8 exiting nerve roots noted)

Thoracic & Lumbar spine:
– exiting nerve root at the disc space is from the level above (eg at T1-T2, exiting nerve roots are T1)
*Cervical Spine: You have Uncovertebral Joints*
*Thoracic/Lumbar Spine: No uncovertebral joints*

-Articulation point of the vertebra
-Composed of inferior and superior articular processes and the facet joint

-Function: carry axial load of body limit range of motion of the spine
-Form back border of the intervertebral foramen
–> *can cause LATERAL CANAL STENOSIS when hypertrophied from osteoarthritis*

-Foramen through which the spinal nerves exit the spinal canal.
-Within foramen, the motor & sensory nerve roots merge into single Spinal Nerve (sensory and motor fibers). Termed “Exiting Nerve”
-

-Spinal cord typically terminates at L1-L2 (Conus Medullaris);

-Inferior to conus medullaris, thecal sac contains pia-wrapped 3-5 lumbar, 5 sacral and 1 coccygeal nerves collectively called *CAUDA EQUINA*

-Cauda Equina = nerves hang like a “horse tail” inferior to L2 within the thecal sac

– CT Myelogram: thecal sac is bright, b/c w/contrast!
– MR: soft tissue easier to see
– facet jts: should look smooth, like a hamburger bun (inf. is top of bun, sup. is bottom of bun) –> some facet arthropathy seen in these images

– similar to last slide

[Supplies whole skin of the leg, the muscles of the back of the thigh and those of the leg & foot

Comprised of spinal nerves L4 through S3

Contains fibers from both the anterior and posterior division of the lumbosacral plexus]

*Type I:*
-T1 hypointense (dark) and T2 hyperintense (bright)
-Bone marrow edema & inflammation
[-Strongly associated w/active low back sxs and segmental instability
-Predicts excellent outcome post lumbar fusion surgery]

*Type II:*
-T1 hyperintense and T2 iso/mildly hyperintense (bright spots)
-Conversion of normal hemopoietic (red) bone marrow into fatty (yellow) marrow
[-Less clearly associated w/LBP
-Indicates more biomechanically stable state
-Superimposed stress may induce conversion to Type I]

*Type III:*
-T1 and T2 hypointense (dark)
-Subcondral bone sclerosis

*Type I:*
-T1 hypointense (dark) and T2 hyperintense (bright)
-bright: bone marrow edema & inflammation

[-Strongly associated w/active low back sxs and segmental instability
-Predicts excellent outcome post lumbar fusion surgery]

*Type II:*
-T1 hyperintense and T2 iso/mildly hyperintense (bright spots)
-Conversion of normal hemopoietic (red) bone marrow into fatty (yellow) marrow
[-Less clearly associated w/LBP
-Indicates more biomechanically stable state
-Superimposed stress may induce conversion to Type I]

*Type III:*
-T1 and T2 hypointense (dark)
-Subcondral bone sclerosis

-“Naked bone” of outer periphery of vertebral body
-Outer fibers of disc (Sharpey’s Fibers) anchor themselves into this region
-*Bone spurs (osteophytes) arise form this region* as a result of prolonged pulling/tugging of Sharpey’s fibers

Nucleus Pulposus:
-*water-rich* gelatinous center of disc
-bear axial load of body; pivot point for movt

Annulus Fibrosus:
-more *fibrous* than nucleus, higher collagen / lower water content
-hold in place the highly pressurized nucleus
-composed of 15-25 concentric sheets of collagen named LAMELLAE.
-outer lamellae = SHARPEY’S FIBERS

Facets = Synovial Joints
-Prone to osteoarthritis
-*Osseous overgrowth can results in lateral canal stenosis (neural foraminal stenosis)*

-Associated with facet synovial cysts and degenerative disc disease

Axial view (lose the nice hamburger shape, excess bone formation)

*Uncovertebral joints (Luschka’s joints)*
-formed between uncinate processes above and uncus below
-exist from C3 to C7
-allow for flexion and extension; limit lateral flexion

*Uncovertebral joint hypertrophy*
-osteophytes (bone spurs) form in response to degeneration of the spine to try to maintain stability of the spine
-can lead to lateral canal (foraminal stenosis) in the cervical spine

Ligamentum Flavum
-provides stability and protection to spine
-connects the vertebral bodies together
-flexible
>> normally thicker when standing or leaning back and thinner when sitting or bending forward

Hypertrophy/Thickening of the Ligamentum Flavum
-natural part of aging process
-spine is trying to provide itself with additional support when injury or aging occurs
-thickened ligament becomes less flexible and weaker and can encroach on the spinal canal

*Radicular pain:*
-Pain arising from the spinal root level (vs referred pain from facet joint, SI joint, etc..)

-Sciatica (most common type of radiculopathy)
-Burning, stinging &/or numbness in buttock, thigh, leg, &/or foot; +/- Back pain

*Non-radicular pain:*
-Pain radiating in a non-dermatomal pattern

Specific type of Radiculopathy where pain is caused by impingement/irritation of one of the three lowest lumbar nerve roots (L4, L5 & S1) which make up the Sciatic Nerve

[Causes of Radiculopathy/Sciatica:
1) Disc herniation induced radiculopathy/sciatica
2) Grade V annular tear induced radiculopathy/sciatica (chemical radiculopathy)
3) Discogenic radiculopathy/sciatica (“referred pain) – irritation of the sinuvertebral nerves along annulus which is perceived as pain]

Treatment is often nonsurgically unless concurrent cauda equina symptoms present or not responding to conservative therapy

Normal annulus fibrosus:
-Strong and keeps pressurized nucleus pulposus from escaping outward

Annular Tears/Fissures:
-Separations between one of more of the annular lamellae
-Avulsion of fibers from the vertebral insertion

Gold Standard = Discography (no longer performed)

MRI: can pick up some annular tears, but not all
-Will affect nearly 40% of chronic back pain sufferers, but often difficult to diagnose

-Contrast MRI better than noncontrast MRI
-NonContrast MRI: *T2 hyperintensity along annulus*
-Contrast MRI: *”lights up” granulation tissue in healing/healed annular disc tear*

free fragment, AKA sequestration

-Displacement of disc material circumferentially (50-100%) beyond edges of ring apophyses
-*Not a type of disc herniation*
-Types:
(1) Symmetrical
(2) Asymmetrical

circumferential

-*Localized (<50%) displacement of disc material beyond limit of disc space* -Disc material may be nucleus, cartilage, fragmented apophyseal bone, anular tissue or combination of aforementioned structures -What defines borders of Disc Space? (1) Cranio-caudad: vertebral body endplates (2) Anterior-Posterior: outer edges of ring apophyses, exclusive of osteophytes

1) Intravertebral disc herniation (Schmorl’s node)
2) Protrusion
3) Extrusion
4) Sequestration

-Intravertebral disc herniation
-Disc extends vertically (up or down) into the vertebral body through a defect in the endplate
-Rarely symptomatic

-Greatest distance (in any plane) between edges of disc material beyond disc space is less than distance between edges of disc material at the base in the same plane.
-PLL is ALWAYS intact (contained disc herniation)
(1) *Focal*: size of protrusion is <25% of disc circumference (2) *Broad-based*: size of protrusion is 25-50% of disc circumference

-In at least one plane, distance between the edges of the disc material beyond disc space is greater than distance between edges of disc material at the base (Dome of herniation is greater in width than base of herniation)
OR
-No continuity exists between the herniated disc material and the disc space

-*PLL is disrupted (uncontained disc herniation)*

axial

saggital: T1 & T2 ONLY
– ID neural foramina region (key-hole structures)

Sequestration
-Extruded disc material completely loses continuity with disc space

Migration
-Extruded disc material migrates away from site of extrusion
-Can be contiguous or noncontinguous (sequestration) with disc space

Based upon sagittal planes through the axial plane

Central Zone:
-Zone between sagittal planes passing through medial edges of each facet (based on Sag Plane)
-Zones on either side of center plane:
(1) Right central
(2) Left central

Subarticular Zone:
-Zone between sagittal planes passing though medial edge of facet and medial edge of pedicle

Foraminal Zone:
-Zone between sagittal planes passing through medial and lateral edges of pedicle

Extraforaminal Zone:
-Zone beyond sagittal plane passing through lateral edge of pedicle

[Sample exam Q:
protrusion in left subarticular zone of L5: descending n root compression symptoms at L5]

Characteristic pattern of neuromuscular and urogenital symptoms resulting from simultaneous compression of multiple lumbosacral nerve roots below the level of the conus medullaris.

Symptoms:
Low back pain
Sciatica (unilateral or bilateral)
Saddle sensory disturbances
Bladder and bowel dysfunction
Variable lower extremity motor and sensory loss

-Immediate referral for MRI or CT
-*Surgical Emergency – immediate surgical consult needed*

– she’ll have an arrow to the issue!