Spinal Disorders

Question 1

What is the anatomy of the vertebral column?

Answer 1

Question 2

What is the anatomy of the spinal cord?

Answer 2

• approx 45cm long
• originates from medulla
• through foramen magnum
• ends as conus medullaris (L1-2 in adult)
• cauda equina - motor + sensory nerve roots exiting through lumbar and sacral foramina
• meningeal coverings of cord continuous with brain
• cord closely ensheathed by pia mater
• pia mater forms denticulate ligaments
• space between arachnoid + pia → CSF
• dura forms tough sheath; ends distally at S2

Question 3

More anatomy of the spinal nerves

Answer 3

Question 4

Anatomy of the intervertebral disc

Answer 4

Question 5

Describe the dermatome distribution of the upper and lower limb

Answer 5

Question 6

What movements are supplied by which nerve roots in the upper limb?

Answer 6

Question 7

Which are the myotomes of the lower limb?

Answer 7

• Hip flexion → L1-2
• Knee extension → L3
• Ankle dorsiflexion → L4
• Ankle plantarflexion → S1-2
• Foot inversion → L4
• Foot eversion → S1
• Big toe dorsiflexion → L5

Question 8

What are the ascending (sensory) tracts of the spinal cord?

Answer 8

Question 9

What are the descending (motor) tracts of the spinal cord?

Answer 9

Question 10

What does the spinal cord look like on MRI?

Answer 10

Question 11

What red flags are important to look out for when taking a history for back pain / spinal disorders?

Answer 11

• extremes of age <20 / >50
• Hx of cancer
• unexplained weight loss
• immunosuppression
• IV drugs, steroids
• trauma
• faecal incontinence / loss of anal sphincter tone
• saddle anaesthesia
• globa/progressive weakness in legs

Question 12

Why is spinal cord compression an emergency?

Answer 12

• requires swift management to prevent irreversible spinal cord injury + long-term disability
• treatment of acute compression → corticosteroids, surgery, radiotherapy
• diagnosis → x-ray or MRI of spine
• spinal cord injury may occur w/ no findings on imaging
• may be acute, sub-acute, chronic
• occurs due to:
  
  • direct cord damage → compression and/or infiltration
  • cord vascular supply compromise

Question 13

Which part of the spinal cord is most commonly injured?

Answer 13

• Cervical (C1-T1) → 55%
• Thoracic (T1-T11) → 15%
• Thoracolumbar (T11-L2) → 15%
• Lumbosacral (L2-S5) → 15% (not cord, cauda equina)

There is a roughly equal distribution between complete and incomplete paraplegia/quadriplegias. Mortality risk is higher in C1-3 compared to C6-8.

Question 14

What are the causes of spinal cord compression?

Answer 14

• trauma (main cause) → RTAs, falls, sports, knife/gunshot wounds, spontaneous disc protrusions, iatrogenic
• malignancy → extradural, intradural, primary + secondary
• infection → discitis, abscesses, osteomyelitis
• haematoma → AVM, spontaneous, trauma
• cystic lesions → arachnoidal, syringomyelia
• pathological fractures → osteoporosis, steroid therapy

Question 15

Which tumours are most likely to metastasise to the bone?

Answer 15

‘BLT Plus Ketchup’

• Breast
• Lung
• Thyroid
• Prostate
• Kidney

Question 16

What are signs and symptoms of spinal cord compression?

Answer 16

• back pain → associated w/ malignancy, compression fractures, infection etc
• sensory → numbness or parasthesia
• motor → weakness or paralysis, hypotonia
• autonomic → bladder or bowel dysfunction
• spasticity → most often w/ malignancy
• neurogenic shock → if lesions in C-spine, hypotension, bradycardia, warm extremities
• Brown-Sequard syndrome

Question 17

What is the pathophysiology of spinal cord injury?

Answer 17

• injury arises from stretching or from pressure
• injures white matter (myelinated tracts) + grey matter (cell bodies) in cord
• causes loss of some sensory modalities + motor function
• spinal cord nerve roots depend on constant blood supply for appropriate energy stores + substrate, to perform axonal signalling
• conditions that interfere either directly or indirectly w/ blood supply will cause malfunction of transmission pathway
• nerve tracts most vulnerable to mechanical pressure include corticospinal + spinocerebellar tracts, and posterior spinal columns

Question 18

Spinal cord injury can be classified as complete and incomplete.

What is meant by this?

Answer 18

• INCOMPLETE → any residual motor or sensory function more than 3 segments below level of injury; sensation or voluntary mvmt in legs; sacral sparing; types of lesion = central cord/Brown Sequard/anterior cord/posterior cord
• COMPLETE → no preservation of any motor and/or sensory function more than 3 segments below level of injury; no voluntary anal contraction; no anal sensation; no s4/5 sensation

Complete cord transection syndrome results in a group of symptoms known as spinal shock + when seen at high cervical level → quadriplegia, resp insufficiency, loss of bladder/bowel fxn, anaesthesia below affected level + neurogenic shock.

ASIA classification for pts w/ acute traumatic spinal cord injury.

Question 19

Transverse myelitis (TM) is a pathogenetically heterogeneous focal inflammatory disorder of the spinal cord. Leads to axonal demyelination. Thought to be viral.

How does it clinically present?

Answer 19

• age 10-10 or 30-39
• motor weakness
• paraesthesias or sensory loss
• bladder → urinary frequency, urgency, incontinence, retention
• bowel → incontinence or constipation
• L’hermitte sign → tingling in limbs on neck flexion
• paroxysmal tonic spasms → painful, involuntary limb spasms
• UMN signs → hyper-reflexia, Babinski +ve, spasticity
• back / trunk / limb pain

Question 20

What are differentials for the patient “off their legs”?

Answer 20

• Transverse myelitis
• Guillain-Barre syndrome
• HIV-related myelopathy
• Amyotrophic lateral sclerosis
• Multiple Sclerosis
• Diabetic neuropathy
• Polymyositis
• Hereditary muscular dystrophy
• Peripheral neuropathy
• Cerebellar origin (ataxia)
• Spinal cord (stenosis / malignant compression / syringomyelia)
• Degenerative ataxias
• Metabolic/Nutritional (vit B12 def/drugs/dizziness)

Question 21

What are the investigations for spinal cord compression?

Answer 21

• CT for bony anatomy
• MRI for soft tissue (cord itself)
• CXR, X-ray spine, FBC, U+E, bone profile, ESR, CK, TFTs, plasma electrophoresis, urine (Bence-jones protein), ABPI

Investigate the rest of the body also - is it cancer (primary or mets)? Is it infection (source)? Is it bony degeneration (osteoporosis)? Is it trauma? Any other injuries?

Question 22

What do MRI findings of spinal cord injury look like?

Answer 22

Question 23

Clinical features depend on the site, level and completeness of the compressive lesion. Any residual motor or sensory function more than 3 segments below the level of injury suggest an incomplete lesion - look for signs of preserved long tract function.

What are 5 types of incomplete injury?

Answer 23

• Central cord syndrome
• Anterior cord syndrome
• Brown-Sequard syndrome
• Posterior cord syndrome
• Cauda Equina syndrome

Whereas, complete lesions show no preservation of motor and/or sensory function more than 3 segments below the level of injury.

Question 24

With any severe, acute spinal cord lesion there are usually two clinical stages. What are these?

Answer 24

• Spinal shock → initially, there is loss of all reflex activity below level of lesion w/ flaccid limbs, atonic bladder + overflow incontinence, atonic bowel, gastric dilatation and loss of genital reflexes + vasomotor control
• Heightened reflex activity → occurs after about 1-2wks + is associated w/ spasticity of limbs, brisk reflexes and extensor plantar responses. Pts develop a spastic bladder (small capacity w/ urgency and frequency, and autonomic emptying) and hyperactive autonomic function (sweating + vasomotor changes)

Question 25

A disc protrusion occurs when the disc nucleus bulges but does not rupture. The nucleus remains contained within the disc structure. What causes **disc protrusion** and how does it present?

Answer 25

* most common cause of disc disease → **spondylosis** * _degenerative_ changes within vertebrae + intervertebral discs occur during **ageing** or secondary to **trauma** or **rheum disease** * damaged discs normally protrude _laterally_ + cause compression of nerve roots → **LMN lesion** * discs can protrude **centrally** + **posteriorly** → results in _cord compression_ when it occurs above level of L1 + causes a spastic paraparesis (usually low cervical or thoracic disc) or tetraparesis (high cervical disc) w/ variable sensory loss + sphincter dysfunction

Question 26

What are the features of **central cord syndrome**?

Answer 26

* most **common** type of injury * usually follows **hyperextension** injury in presence of osteophytic spurs, often in _older_ people * _motor deficit_ → **upper limb** \>\>\> lower limb → **_weak arms_** (_more_ than legs) * surgery often employed for ongoing compression (non-emergency) * **pathophys** → centremost region of spinal cord is a *vascular watershed zone* - more susceptible to injury from _oedema_; long tract fibres in cervical cord are somatotopically organised such that **upper limbs** are more _medial_ than lower limbs * **sensory** → varying degrees of disturbance below level of lesion; "suspended sensory loss"; "cape like distribution"; myelopathic findings include **sphincter dysfunction** (urinary retention)

Question 27

What are the features of **anterior cord syndrome**?

Answer 27

* cord infarction in region supplied by **anterior spinal artery** * **paraplegia**; *quadriplegia* if _above_ C7 * dissociated sensory loss → **loss of pain + temp**; preserved _dorsal columns_ * **causes** → occlusion of anterior spinal artery; dislocated bone fragment; traumatic herniated disc * *_worst prognosis_* of the incomplete injuries * only **10-20%** recover functional motor control * sensation may return enough to help **prevent injuries** (burns, ulcers)

Question 28

What are the features of **Brown-Séquard syndrome**?

Answer 28

* partial (**unilateral**) cord lesion * **laterally** placed lesion causing compression on _one side_ - spinal cord hemisection * _ipsilateral_ findings → **motor paralysis** (corticospinal tract lesion) below level of lesion; loss of posterior column fxn (**proprioception** + **vibration**) * contralateral findings → dissociated sensory loss; **loss of pain/temp** below level of lesion *(begining 1-2 segments below)* (spinothalamic tract); **preserved light touch** due to redundant ipsilateral + contralateral paths (anterior spinothalamic tract)

Question 29

What are the features of **posterior cord syndrome**?

Answer 29

* AKA "contusio cervicalis posterior" * _rare!_ * produces **pain** + **paraesthesia** (often without a burning quality) in the **neck, upper arms + torso** * may be **mild paresis** of upper limbs * long tract findings are minimal

Question 30

**Cauda equina syndrome** results from _compression_ of the cauda equina nerve roots. It can be caused by any compressive lesion below L1/L2 - prolapsed disc, tumour, abscess, trauma and haematoma. What is the **clinical presentation**?

Answer 30

* **leg pain** → bilateral +/- lower back pain * **sacral anaesthesia** +/- loss of anal reflex * **urinary retention** w/ overflow incontinence * **motor weakness** of L4, L5, S1 + S2 * **sexual dysfunction** Triad of leg pain, saddle anaesthesia and urinary disturbance *isn't* always the case - any pt who has sensory disturbance in S2/3/4 should have **high index of suspicion** - have a low threshold for scanning → _lumbar spine MRI_ **Timing** of symptom onset is critical bc it influences timing of surgery ie. the longer symptoms present, the less likely to regain function. **Completeness** of symptoms also important as strongly correlated w/ recovery potential - pts having incomplete cauda equina have a better prognosis. _Rx → urgent surgery in form of laminectomy_

Question 31

What are the **main goals** of **treatment** for spinal cord injury?

Answer 31

* to prevent **clinical deterioration** from progressive degenerative changes of spinal cord injury * to relieve **pain + symptoms** * to restore **functional ability** The following groups can be considered in the treatment approach → acute, traumatic SCI; epidural abscess; malignant SCC; intervertebral disc compression

Question 32

Acute traumatic SCI is a **medical emergency** and management should be undertaken at a trauma centre w/ experience in SCI and in-house neurosurgical expertise. What is the **management** of (traumatic) spinal cord compression?

Answer 32

* **_ABCDE_** * _immobilisation_ w/ **cervical collar** + backboard/head strap while clinical exam/imaging done * confirmed spinal injury? → refer for **neurosurg evaluation** for decompression + stabilisation _within 24hrs_ * monitor pt in **ICU** → cardiac / haemodynamic / resp monitoring * management depends on site + **_stability_** of injury\*\* * **_unstable_** → risks further damage to spinal cord + roots, requires operative fixation eg. screws/rods or non-surgical immobilisation eg. traction, HALO or plaster jacket * **_stable_** → can try to manage conservatively eg. w/ rigid collar * after initial management, pt may require **long-term spinal rehab** so transfer to appropriate speicalised spinal injury centre ## Footnote *\*\***Stability** = ability of the spine under physiological loads to limit displacement as to prevent injury or irritation of the spinal cord and nerve roots and to prevent incapacitating deformity or pain due to structural changes*

Question 33

What are **other considerations/further management** for traumatic spinal cord compression, following initial management?

Answer 33

* **DVT/PE prevention** * **steroids** → high-dose **methylprednisolone** (given within 8hrs) * treatment of autonomic dysfunction + prevention of hypotension * **NG tube** (prevent vomiting/aspiration) * prevention of gastric stress ulceration * **supportive therapies:** * nutritional support * mechanically assisted ventilation or manually assisted cough * bladder + bowel management: catheterisation/laxatives/bowel evacuation * pressure sore prevention: regular turning + physio

Question 34

What is the specific **management** of an **epidural abscess**, in relation to spinal cord compression?

Answer 34

* same principles as trauma → *does spinal cord need decompression? does spine need stabilisation?* * take sample of abscess during surgery → send to lab for **MC+S** * treat w/ empirical ABx _initially_ then _adjust_ according to culture results * **ABx treatment** advised for at least **12 weeks** * pathogens → *Staph aureus* (most common) * identify **underlying source** of infection * dental X-rays * cardiac ECHO * swabs from any wounds * blood cultures * urine culture

Question 35

**Malignanct spinal cord compression** is one of the most _devastating_ + dreaded complications of cancer. Occurs in 5% of all cancer patients and amounts for 50% of adult acute myelopathies. Rapid neuro deterioration can result in paralysis and loss of sphincter function. **Early diagnosis + treatment** of condition is *vital* to keep patients ambulatory and thus have a positive impact on quality of life. We mentioned the source of primary cancerous sites previously, **where** do these **metastasize** to in the bone most commonly?

Answer 35

* **thoracic** most often * usually involves vertebral body + pedicles

Question 36

MSSC: All patients should be referred to specialist neuro-onco spinal MSCC teams for discussion. All patients require steroids + biopsy if no prior diagnosis exists. **Steroids** provide relief from pain, reduce tumour-associated oedema and may be oncolytic for some tumours. What are **factors** _supporting_ the following methods of treatment?: * **decompressive suergery (plus radiotherapy)** * **just radiotherapy**

Answer 36

Question 37

What are features of the **intervertebral disc**?

Answer 37

* **function** → permit stable motion of spine while supporting + distributing loads under movement * **annulus fibrosus** → multilaminated ligament encompasses periphery of disc space, tough + collagenous * **nucleus pulposus** → jelly like, central portion, remnant of notochord * **ageing** → w/ age the nucleus becomes _less_ _hydrated_ + more collagenous, it discolours, changing from white to yellow-brown in colour through accumulation of product of non-enzymatic glycosylation; these **_reduce flexibility_**

Question 38

What is a **myelopathy** and its common features?

Answer 38

* pathological condition of **_spinal cord_** * clinical features depend on which *level* affected + *extent* (anterior, posterior, lateral) of the pathology * may include: * UMN signs (weakness, spasticity, clumsiness, altered tone) * pathological hyperreflexia + upgoing plantars * sensory deficits * bowel/bladder symptoms + sexual dysfunctions

Question 39

What is a **radiculopathy** and its common features?

Answer 39

* pathological condition of **_nerve root_** * **pain** in distribution of that nerve root * dermatomal **sensory** disturbances * **weakness** of muscle innervated by that nerve root * hypoactive muscle stretch reflexes of same muscles

Question 40

**Disc prolapse** is the most common cause of nerve root compression. What is **disc prolapse** and who is at risk?

Answer 40

* **ie. slipped disc** * occurs when outer ring becomes weak or torn + allows inner portion to **slip out** * this can happen w/ age or certain motions may also cause it, esp twisting or turning to lift an object * **overweight** individuals are also at increased risk bc their discs must support additional weight * more common in **men** * rupture usually occurs in **posterior-lateral** direction

Question 41

**Sciatica** is the most common lesion in the **lumbar** region causing compression of L5 and S1 roots due to lateral prolapse of L4/5 and L5/S1. What are the **clinical features** of sciatica?

Answer 41

* **back pain** progressing to **leg pain**, **radiating** down buttock * pain _worse_ on **coughing** * weakness + numbness * **bladder** problems * paravertebral muscle spasm * antalgic **gait** * reduced passive straight leg raise * motor + sensory disturbance dependent on level, eg. weak EHL (L5)

Question 42

For sciatica, _investigations_ include **MRI**, **nerve conduction studies** and **myelography**. What is the **treatment** for sciatica?

Answer 42

* **conservative management** → analgesia, physio * **pain clinic** → nerve root injections / epidural injections * 85% w/ acute disc herniation will improve without surgery in 6wks * 70% within 4 weeks * _surgical_ treatment → **lumbar decompression** (discectomy/microdiscectomy), indicated if: * failed conservative treatment * severe pain * progressive motor deficit * cauda equina syndrome

Question 43

**Lumbar spinal stenosis** is a condition in which the central canal is narrowed by tumour, disk prolapse or other similar degenerative changes. What **clinical features** will patients present with?

Answer 43

* **back pain** * **neurogenic claudication** → progressive bilateral leg pain, numbness, weakness * **limitation of walking distance** * **postural relief** → sitting is better than standing + pt may find it easier to walk up rather than downhill * **bladder** symptoms * examination may be unremarkable

Question 44

What is the **pathophysiology** of lumbar spinal stenosis?

Answer 44

**Degenerative** disease is the commonest underlying cause. Degeneration is believed to begin in the intervertebral disk where biochemical changes such as cell death and **loss** of **proteoglycan** and **water** content lead to progressive disk bulging and collapse. This process leads to an increased stress transfer to the **posterior facet joints**, which accelerates cartilaginous degeneration, hypertrophy, and **osteophyte** formation; this is associated with thickening and distortion of the ligamentum flavum. The combination of the **ventral disk bulging**, **osteophyte formation** at the dorsal facet, and **ligamentum flavum hyptertrophy** combine to circumferentially _narrow_ the spinal canal and the space available for the neural elements. The compression of the nerve roots of the cauda equina leads to the characteristic clinical signs and symptoms of lumbar spinal stenosis.

Question 45

What are the **investigations** and **treatment** for lumbar spinal stenosis?

Answer 45

* **INVESTIGATIONS** → Plain X-Ray and _MRI_ (most accurate) * **CONSERVATIVE MX** → analgesia, physio, osteopathy, chiropractic, facet joint injections, epidural injections * **SURGERY MX** → _lumbar laminectomy_, laminectomy + fusion, interspinous distraction procedure

Question 46

Degenerative cervical myelopathy (DCM) has a number of risk factors, which include smoking due to its effects on the intervertebral discs, genetics and occupation - those exposing patients to high axial loading. What are the **clinical features** of cervical myelopathy?

Answer 46

* **pain** → neck, upper or lower limbs * loss of motor function → digital **dexterity**, preventing simple tasks such as holding a fork or doing **up their shirt buttons**, arm or leg weakness/stiffness leading to impaired gait + balance * loss of sensory fxn → urinary or faecal **incontinence** + impotence * **Hoffman's sign** → reflex test to assess for cervical myelopathy: gently flick one finger on a patient's hand, a positive test results in reflex twitching of the other fingers on the same hand in response to the flick MRI of spine is gold standard → may reveal disc degeneration + ligament hypertrophy w/ accompanying cord signal change.

Question 47

As with lumbar disc herniation, cervical disc herniation can cause compression of the *_nerve root_*. This results in radicular pain down the arm in the corresponding dermatome (**_brachalgia_**). What are other features of cervical **radiculopathy**?

Answer 47

* almost all herniated cervical discs cause **painful limitation of neck movement** * some pts find relief **elevating arm** + cupping back or top of head with their hand * **Lhermitte's sign** → electric-shock like sensation radiating down spine may be present * **Spurling's sign** → radicular pain reproduced when examiner exerts downward pressure on vertex tilting head towards sympomatic side, this causes narrowing of intervertebral foramen + possibly increases disc bulge