Spinal Cord Compression

Neurology Academic ½-day

(Emergency Lecture Series)

Chenjie Xia (PGY-3)

Wednesday, July 22, 2009

Test your knowledge

• The ER staff calls you for: “a 58 yo man, known prostate cancer, presenting with back pain x 2 months and leg weakness x 1 week” The proper response should be:– A) “I will come see the patient immediately”– B) “I’ll come see the patient as soon as I finish

rounding on the floor.”– C) “I haven’t had lunch yet…I’ll come in the

afternoon.”– D) “Just leave me his Medicare and phone #’s, I’ll

book him an appointment with the Urgent Neurology Clinic”

Test your knowledge

• The ER staff calls you for: “a 58 yo man, known prostate cancer, presenting with back pain x 2 months and leg weakness x 1 week” The proper response should be:– A) “I will come see the patient immediately”– B) “I’ll come see the patient as soon as I finish

rounding on the floor.”– C) “I haven’t had lunch yet…I’ll come in the

afternoon.”– D) “Just leave me his Medicare and phone #’s, I’ll

book him an appointment with the urgent neurology clinic”

One of the only true neurological emergencies…

where time is of the essence (i.e. drop everything else you’re doing)

Test your knowledge

• Can you name 2 causes of spinal cord compression and 2 mimickers of spinal cord compression?

Differential Diagnosis• Common causes

– Neoplasm – Fracture– Cervical / lumbar stenosis– Herniated disk– Spinal infection/abscess– Spinal hemorrhage– Conus medullaris lipomas

• Mimickers– Anterior spinal artery infarction– Spinal AVMs – Multiple sclerosis / transverse myelitis– Neurosarcoidosis– Plexopathy

Anatomy review

• Spinal cord ends at L1-L2

• Dural sac ends at S2

• Terminology– Conus medullaris: most

distal bulbous part– Filum termiale: tapering

part of conus medullaris (mostly fibrous tissue)

– Cauda equina: distal collection of nerve roots

http://en.wikipedia.org/wiki/Filum_terminale

The real estate of cord compression…location is key!

• Intradural intramedullary:– astrocytomas, ependymomas,

hemangioblastomas (primary spinal tumours)

• Intradural extramedullary:– Meningiomas– nerve sheath tumours

(schwannomas and neurofibromas)

• Epidural: metastases

http://www.emory.edu/ANATOMY/AnatomyManual/back.html

Test your knowledge

• What is the most common mechanism leading to epidural metastasis?

Pathophysiology - Epidural Mets

1) Hematogenous spread to bone marrow– Most common mechanism – Most at vertebral mass

2) Direct invasion through intervertebral foramina from paravertebral source

– Second most common mechanism– Typical of lymphoma

3) Retrograde venous spread– With increased abdominal pressure, abdo/pelvis venous

system drains via Batson paravertebral plexus to epidural venous plexus

– Common for pelvic tumours (prostate)

Pathophysiology - Cord Damage

• Severity– Mild: minor Asx indentation of thecal sac– Severe: strangulation of cord with paraplegia

• Progression– Epidural venous plexus obstructed BBB breakdown

vasogenic edema PGD (hence utility of steroids)– First WM involved demyelination– Then GM involved cord ischemia / infarction– Irreversible damage if prolonged compression with cord

infarction (> 1 week)

Test your knowledge

• Which of the following is true?– A) Patients with cancer have high likelihood of

developing spinal cord compression– B) Patients with cancer are more likely to

develop vertebral metastases without spinal cord compression

– C) The most common primary cancers responsible for cord compression are similar for adults and children

Test your knowledge

• Which of the following is true?– A) Patients with cancer have high likelihood of

developing spinal cord compression– B) Patients with cancer are more likely to

develop vertebral metastases without spinal cord compression

– C) The most common primary cancers responsible for cord compression are similar for adults and children

Epidemiology

• Most common – Adults: lung, breast, prostate, lymphoma, sarcoma,

kidney– Children: Ewing’s sarcoma, neuroblastoma, germ

cell neoplasms, Hodgkin’s lymphoma

• In cancer patients– likelihood of epidural spinal cord compression 5-yrs

before death = 2.5%– Vertebral metastases >>> ESCC

That being said…

all patients with new back pain and known malignancy have spinal cord compression until proven otherwise

Now that you’ve thought of the Dx, focus Hx and exam on:

1) Back pain

2) Weakness

3) Reflexes

4) Sensory loss

5) Spincter control

Test your knowledge

• Which of the following regarding epidural spinal cord compression is false?– A) Pain is a more common initial presentation

than weakness – B) Initial severity of weakness and ambulation

status are important prognostic factors– C) The sensory level can be 5 levels below the

actual level of compression– D) Pain improves with supine position

Test your knowledge

• Which of the following regarding epidural spinal cord compression is false?– A) Pain is a more common initial presentation

than weakness – B) The sensory level can be 5 levels below the

actual level of compression– C) Initial severity of weakness and ambulation

status are important prognostic factors– D) Pain improves with supine position

Back Pain

• Initial complaint in 96%• May precede neuro Sx by days or years

(duration related to tumour growth rate); average 7 weeks

• Constant, worse with coughing, sneezing, straining, exercise

• Worse when supine (as opposed to disc disease)

• May be radicular (L’hermitte sign in cervical lesion, “tight rope / band around chest” in thoracic lesions)

• Percuss / palpate chest to better localize pain

Weakness

• Present in 80% initially (50% ambulatory; 35% paraparetic; 15% paraplegic)

• Rate of progression depends on tumour growth rate (30% become paraplegic in 1 week)

• Usu. paraplegia = cord infarction (likely irreversible)

• Pattern of weakness depends on site of compression

– e.g. above conus = pyramidal pattern– T6-T10: Beevor sign

Reflexes

• Hyperreflexia, upgoing toes (may not be seen in cauda equina lesions)

• Abdominal reflexes (helpful if present and asymmetric)

Sensory loss

• Present in 78% of patients at diagnosis• “Pins and needles,” “numb” • Look for sensory level

– Begin distally, then ascend (use pin, go all the way up to neck)

– Look for Brown-Sequard syndrome– Usu 1-5 levels below actual compression

• Pattern as per site of compression• Above cauda equina, if intramedullary sparing of sacral

dermatomes • At cauda equina saddle anesthesia

Test your knowledge

• Patients with epidural spinal cord compression may develop:– A) Urinary incontinence– B) Urinary retention– C) Stool incontinence– D) B and C only– E) A, B, and C

Test your knowledge

• Patients with epidural spinal cord compression may develop:– A) Urinary incontinence– B) Urinary retention– C) Stool incontinence– D) B and C only– E) A, B, and C

Spincters

• Urinary– Contraction of detrusor muscle

innervated by S2-3-4– Initially flaccid and distended

bladder retention– Then “decentralized bladder”

becomes active and shrinks, bladder wall hypertrophies incontinence, frequency

– Ask about urination, palpate bladder for fullness, bladder scan and Foley insertion to document urine volume

http://www.accessmedicine.com/content.aspx?aID=707106&searchStr=neurogenic+bladder

Spincters

• Rectal tone– External anal sphincter

and puborectalis muscle innervated by S3-4

– Loss of anal tone stool incontinence

– Similar mechanism for bulbocavernosus reflex

– DRE, anal wink, tugging at Foley http://www.netterimages.com/image/12555.htm

Conus vs Cauda

• Spinal cord ends at L1-L2

• Dural sac ends at S2

• Terminology– Conus medullaris: most

distal bulbous part– Filum termiale: tapering

part of conus medullaris (mostly fibrous tissue)

– Cauda equina: distal collection of nerve roots

http://en.wikipedia.org/wiki/Filum_terminale

Conus vs Cauda

Conus Cauda

Sudden and bilateral onset Gradual and unilateral onset

Radicular pain less prominent Radicular pain more prominent

More low back pain Less low back pain

Symmetric, distal, hyperreflexic paresis

Asymmetric, areflexic paraplegia

Symmetric, bilateral, typically perianal area sensory loss, sensory dissociation occurs

Asymmetric, unilateral, typically saddle area, no sensory dissociation

Early spincter signs Late spincter signs

Intramedullary vs Extramedullary

• Intradural intramedullary:– astrocytomas, ependymomas,

hemangioblastomas (primary spinal tumours)

• Intradural extramedullary:– Meningiomas– nerve sheath tumours

(schwannomas and neurofibromas)

• Epidural: metastases

http://www.emory.edu/ANATOMY/AnatomyManual/back.html

Intramedullary vs Extramedullary

Intramedullary Extramedullary

Poorly localized burning pain Prominent radicular pain

“sacral sparing” Early sacral sensory loss

Corticospinal tract signs appear later

Early spastic weakness in legs

Usually rapid progression (usually malignant lesion)

Usually slow progression (usually benign lesion)

http://www.accessmedicine.com/content.aspx?aID=2904376

Although history and exam are important, one cannot make a

diagnosis without imaging.

1) Better to err on side of caution, i.e. obtain imaging even if clinical suspicion low

2) All patients eventually end up having neuroimaging, i.e. MRI

3) Key point is urgency of timing of neuroimaging

Test your knowledge

• If clinical suspicion is high, your next step should be:

A) Call your attending

B) Call the radiologist

C) Call the radiation oncologist

D) Call the neurosurgeon

E) Call the orthopedic surgeon

F) Call the oncologist

Test your knowledge

• If clinical suspicion is high, your next step should be:

A) Call your attending

B) Call the radiologist

C) Call the radiation oncologist

D) Call the neurosurgeon

E) Call the orthopedic surgeon

F) Call the oncologist

Test your knowledge

• In a patient with suspected compression at L3 level, you should order an MRI of:

A) The cervical spine

B) The thoracic spine

C) The lumbar spine

D) The sacral spine

E) The lumbo-sacral spine

F) The entire spine

Test your knowledge

• In a patient with suspected compression at L3 level, you should order an MRI of:

A) The cervical spine

B) The thoracic spine

C) The lumbar spine

D) The sacral spine

E) The lumbo-sacral spine

F) The entire spine

What to image

• Always image entire spine:– Spinal cord is shorter than vertebral spinal

column; imaging LS spine means you’re not imaging the cord at all

– Exam is not always reliable for level of compression

– Multiple sites of deposits are frequent in epidural spinal cord metastases (1/3 of patients)

Test your knowledge

• Which of the following patients may safely undergo MRI:– A) A patient with a metal hip prosthesis– B) A patient with an “MRI-compatible” PPM– C) A patient with a cochlear implant– D) A patient with CKD on dialysis– E) A patient with dental braces

Test your knowledge

• Which of the following patients may safely undergo MRI:– A) A patient with a metal hip prosthesis– B) A patient with an “MRI-compatible” PPM– C) A patient with a cochlear implant– D) A patient with CKD on dialysis– E) A patient with dental braces

MRI contraindications

1) Implanted devices and foreign bodies– Cardiovascular devices (stents, valves, IVC filters, embolization

coils, loop recorder, pacing devices)• Most are MR safe/conditional, depends on specific brand• Timing: If non-ferromagnetic, can scan immediately; If ferromagnetic,

prudent to wait 6 wks for proper tissue anchoring• Usually recommends < 3Tesla• Unsafe: Swann-Ganz catheters, temporary epicardial pacing wires,

transvenous temporary pacing leads, PPM/ICDs, IABP, VADs• Stored information may be affected e.g. loop recorder (download

beforehand)

– Unsafe: nerve stimulators, cochlear implants, ferromagnetic aneurysm clips, intraocular/intraorbial metal fragments

– Safe: dental alloys / wires / prostheses, most orthopedic implants– Image artifacts

MRI contraindications2) Unstable patients

– no MRI, unless urgent clinical indication and no other alternative3) Pregnancy:

– magnetic field and gadolinium probably safe, but unproven– Negative effect of noise on fetus?

4) Other– Claustrophobic and obese patients: open MR machines– Agitated: sedation– Tattoo: usually not a problem– Contrast agents

• Mod-severe CKD: contrast nephropathy (risk <<< iodinated contrast)• Dialysis, hepatorenal syndrome, periooperative liver transplant:

nephrogenic systemic fibrosis

• Decisions best on a case-by-case basis• ALWAYS inform radiologist about ANY possible contraindication

Unfit for MRI…

What next?

CT-Myelogram

http://www.urmc.rochester.edu/smd/Rad/neurocases/Case34/Fig2.jpghttp://www.beliefnet.com/healthandhealing/images/exh57177_97870_1_lumbar_myelogram.jpeg

Diagnosis

• MRI– Test of choice

ADVANTAGES– Non-invasive– No procedural complication (e.g.

risk of herniation with brain mets, hemorrhage with coagulopathies, neuro deterioration with CSF retrieval)

– Visualization of spinal parenchyma, adjacent bone and soft tissues

– Can image entire spine even if subarachnoid block present

– Needed to plan radiation and Sx

• CT myelography– 2nd test of choice

ADVANTAGES– CSF can be obtained for

analysis– Safe for claustrophobic

patients– Safe for ferromagnetic

implant (valves, PM, implants, shrapnel)

– No movement artifact

Treatment

• The obvious…– Abscess: ABX, Sx– Hematoma: correct coagulopathy, Sx– Fracture / stenosis: Sx

• Goals of treatment for epidural metastases

– Pain control– Preserve or improve neurological function

Test your knowledge

• Which of the following is false regarding treatments for ESCC:– A) There is no significant difference in survival between

high dose and low dose Decadron– B) There is no significant difference in survival between

short- and protracted-course radiation therapy– C) There is no significant difference between surgery

followed by radiation therapy and radiation therapy alone

– D) Anterior approach is superior to posterior approach in vertebral metastasis removal

Test your knowledge

• Which of the following is false regarding treatments for ESCC:– A) There is no significant difference in survival between

high dose and low dose Decadron– B) There is no significant difference in survival between

short- and protracted-course radiation therapy– C) There is no significant difference between surgery

followed by radiation therapy and radiation therapy alone

– D) Anterior approach is superior to posterior approach in vertebral metastasis removal

Steroids (Decadron)

Initial presentation Dose recommended

Mild disease, no neurological Sx Forgo steroids

Moderate disease, minimal neurological dysfunction, < 80% spinal block

Low dose: 10mg x1 IV

then 4mg q6h;

then taper rapidly when definitive Rx underway

Severe disease, significant neurological dyxfunction (paraparetic, paraplegic); > 80% spinal block

High dose: 100mg x1 IV

then 24mg q6h x at least 72 hours

then taper gradually when definitive Rx underway

Steroids

• Clearly improve neurological outcome

• It seems no difference b/w initial dose of 10mg or 100mg for mild disease

• Adverse effects (gastric ulcers, hyperglycemia, psychosis, life threatening infections, etc)

Radiotherapy

• RT portal: centered on spine, 2 vertebral bodies above and below myelographic block

• No difference in functional outcome or overall survival b/w different dosing regimens

• Protracted course had better local control of tumour (less recurrence within field)

• Overall success depends on inherent radiosensitivity of tumour, neuro status at onset of RTX, timing of RTX (earlier better)

Surgery

• Needed for tissue Dx if 1st presentation of cancer or if spine instability

• Adverse effects (wound closure, infection, spinal instability, nonfusion)

• May worsen pain• Older trials (posterior approach):

– Sx + RTX = RTX alone

• Recent trials (anterior approach):– Sx + RTX > RTX alone

• Future direction more geared toward Sx?• Careful case-by-case selection

Supportive

• Pain management (steroids usually relieve pain, opioids help)

• Bedrest not helpful (except if has spine instability)

• VTE prophylaxis: heparin sc, TED stockings, compression

• Catheterization, laxatives

• Pressure sores

Prognosis

• Most important Px factors: weakness at presentation• Duration of Sx prior to presentation correlate with Px• Sparing of sphincter and sacral sensory = good Px• Px depends on radiosensitivity of tumour• Children overall prognosis better than adults• Median survival 6 months• Recurrence rate 20%

Take Home Messages

• Suspect spinal cord compression in all patients with cancer and back pain, +/- weakness, sphincter signs

• Goal of history and exam: – assess severity of neuro deficits (weakness, sensory, sphincter)– localize lesion (pattern of weakness, sensory level)

• MRI if no contraindication, image whole spine• Involve all relevant consultants• No difference between high and low dose Decadron• Act fast, prognosis directly related to duration and

severity of neuro deficits• Overall poor prognosis, but pain control and optimize

neuro status crucial for palliation

References.• Medlink: Metastatic epidural spinal cord compression. www.medlink.com. Accessed

2009/07/19• Cole JS and Patchell, RA.. Metastatic epidural spinal cord compression. Lancet Neurol.

2008 May;7(5):459-66• Uptodate: Principles of Magnetic Resonance Imaging (MRI). www.uptodate.com Accessed

2009/07/19• Uptodate: Treatment and prognosis of epidural spinal cord compression, including cauda

equina syndrome. www.uptodate.com Accessed 2009/07/19• Uptodate: Clinical features and diagnosis of epidural spinal cord compressio, including

cauda equina syndrome. www.uptodate.com Accessed 2009/07/19• Medlink: http/www.uptodateonline.com/online/content/topic.do?topicKey=noninvas/

16985&selectedTitle=3~150&source=search_result, accessed 2009/07/19• eMedicine Online http://emedicine.medscape.com/article/1148690-overview, accessed

2009/07/19• Raaijmakers, E. et al. Acta Oncologia 2001;40(1):88-91. Always on a Friday? Time pattern

of referral for spinal cord compression.• Harrison’s Online. Access Medicine.

http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4 Diseases of the spinal cord