Spinal Metastasis

EpidemiologyThoracic Metastasis

 

80% cancer patients have spinal metastasis at autopsy 

 

Spine is number one site for bony metastasis (50%)

 

Cause

 

Hexagon: PBBLTK

 

                 Prostate    Breast

 

Bronchus      MM     Lymphoma        Bowel

   

                 Renal        Thyroid

 

NHx

 

20% of develop cord compression

30% survive >12/12

 

Pathology

 

Site

- thoracic spine  - 70%

- lumbosacral > cervical spine

 

Usually multilevel 

 

Vertebral body 

- 85%

- usually posterior body near pedicles

- posterior elements uncommon

 

Symptoms

- neural compression - demyelination / ischaemia

- pathological fracture

- spinal instability

 

Method of Spread

 

1.  Arterial metastasis

- haematogenous via nutrient arteries

- lung / breast

 

2.  Direct invasion

- through intervertebral foramen 

- lymphoma

 

3. Venous 

- via Batson's Plexus

- valveless veins from the pelvis to the internal venous plexus of the spine / prostate

- GIT tumours commonly spread to liver first via the portal system 

- then later to bone

 

4.  Lymphatic

 

Clinical

 

Pain

- 95% neoplastic pain (night and rest pain)

 

Weakness

- 75% at diagnosis

- bilateral & symmetrical

 

Sensory loss

- 50% at diagnosis

- ssually affects the feet first 

 

Loss of sphincter control

- 50% at diagnosis

 

X-ray

 

75% have abnormality

 

Winking Owl Sign

- pedicle loss on AP

 

Lytic / Sclerotic lesion

- need 30% bone loss to see lytic area

 

Vertebral body collapse 

 

Lumbar Metastasis XrayCervical Metastasis MRI

 

Bone Scan

 

Very sensitive 

- detect metastasis > 2mm

- screening tool

 

False positive

- crush fracture

 

False negative

- myeloma

 

"Superscan"

- symmetric increased uptake

- metastatic disease

- renal or endocrine abnormality

 

CT Scan 

 

Define

- bony abnormality

- deformity

- potential instability

 

Cervical Lesions

 

Cervical Spine Metastasis CTDens Metastasis

 

Lumbar

 

Lumbar Metastasis CTLumbar Spinal Met CT

 

MRI

 

Define

- soft tissue masses 

- nerve and cord impingement

 

Lumbar Metastasis MRI

 

Metastatic Tumour L1 MRI T1Metastatic Tumour L1 MRI Axial

 

Cervical Metastasis MRI

 

Classification Harrington

 

Class I

- Minimal bone involvement

 

Class II

- Bone destruction < 1/2 body / no instability / no cord compression 

 

Class III

- Spinal canal compromise due to epidural disease / no significant bone involvement

 

Class IV

- Pathological fracture ± deformity / no significant neurological compromise

 

Class V

- pathological fracture with collapse / instability & neurological compromise

 

Management

 

Prognosis

 

Outcome after treatment = Neurological impairment before treatment

- most ambulatory patients remain ambulatory after treatment

- few paraplegic patients are able to walk after treatment

 

Radiotherapy v Surgery

 

Patchell et al Lancet et al

- randomised multicentred trial

- patients with spinal cord compression from metastasis

- trial had to be stopped

- superior results for surgery c.f. radiotherapy and steroids

- improved patient walking ability / retained walking ability

- better maintenance of continence and Frankel grades

 

Goals

 

1. Preserve neurological function

- ambulation

- bladder and bowel 

 

2. Pain relief

 

3. Spinal stability

 

Decision making

 

Team approach

- oncologists

- radiation oncologists

- palliative medicine

 

Issues

- life expectancy

- fitness for surgery

- tumour type

- spinal stability

 

Harrington Classification

 

Group 1 & 2 +/- 3

- radiotherapy +/- chemotherapy

 

Group 4 & 5

- collapse / instability / impending deformity / deformity / neurology

- surgery

 

Radiotherapy

 

Sensitivity

 

Very - myeloma, lymphoma

Moderate - breast, lung, bowel, prostate

Resistant - thyroid, kidney, melanoma

 

Indications

- Harrington 1 & 2 +/- 3 radiosensitive

- no neurology

- neurology with poor prognosis or unfit for surgery

 

Operative Management

 

Indications

- neurology / cord compression

- failure of radiotherapy

- deformity

- instability

- > 3/12 to live

- fit for surgery

 

Instability

- > 50% height loss

- anterior and posterior columns at same level

- bone loss > 2 vertebrae

 

Options

 

1.  Decompressive laminectomy

- historical operative associated with poor outcomes

 

2.  Percutaneous PMMA / Vertebroplasty

 

Indications

- stable lesion

 

Spinal Met Percutaneous PMMA

 

3.  Posterior stabilisation

 

A.  Long segment stabilisation

 

Thoracic Spine Pathological Fracture StabilisationCervical Tumour Posterior Stabilisation

 

B.  Short segment stabilisation + PMMA

 

Lumbar Metastasis Posterior Stabilisation with PMMAVertebral Met Posterior Stabilisation + PMMA

 

3.  Corpectomy / PMMA / Anterior stabilisation

 

Technique

- remove body and disc to dura

- PMMA sufficient if LE < 6 months

- titanium cage and BG / structural graft if LE > 6/12

- stabilised with anterior plates

 

Cervical Spine Metastasis Anterior StabilisationCervical Spine Anterior Stabilisation 2

 

Post op Radiotherapy

 

Week 2 if no bone graft

Week 6 if bone graft used