Spinal Cord Compression

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 plexusto 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

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: Back pain Weakness Reflexes Sensory loss 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

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

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

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

Although history and exam are important, one cannot make a diagnosis without imaging. Better to err on side of caution, i.e. obtain imaging even if clinical suspicion low All patients eventually end up having neuroimaging, i.e. MRI Key point is urgency of timing of neuroimaging

Test your knowledge • If clinical suspicion is high, your next step should be: • Call your attending • Call the radiologist • Call the radiation oncologist • Call the neurosurgeon • Call the orthopedic surgeon • Call the oncologist

Test your knowledge • In a patient with suspected compression at L3 level, you should order an MRI of: • The cervical spine • The thoracic spine • The lumbar spine • The sacral spine • The lumbo-sacral spine • 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

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 informationmay 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 contraindications 2) Unstable patients • no MRI, unless urgent clinical indication and no other alternative 3) 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.jpg http://www.beliefnet.com/healthandhealing/images/exh57177_97870_1_lumbar_myelogram.jpeg

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 Diagnosis

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

Steroids (Decadron)

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)

Spinal Cord Compression