Malignant Spinal Cord Compression

What is it?

A real emergency. Tumour, usually a bony metastasis in the vertebra grows and presses on the spinal cord. Initially there may be pain and tenderness at the site of the metastasis. 95% give a history of back pain in the preceding 6-7 weeks. As the tumour grows, increasing pressure on the spinal cord reaches a critical point and often suddenly produces:

Weakness (usually bilateral)
Sensory Disturbance (late sign)
Sphincter Disturbance (late sign)

If undetected or untreated this can rapidly progress to:

Paralysis (very late sign)
Numbness (very late sign)
Double Incontinence (very late sign)

Why is it important?

Early detection and treatment can prevent paralysis and double incontinence. It is not a fatal condition and 30% of patients will survive at least a year. Although rare, it is devastating if diagnosed too late as irreversible paraplegia ensues.

70% of patients walking at the time of diagnosis retain their mobility.
Less than 5% of patients with paraplegia at the time of diagnosis regain any mobility.

How common is it?

Cord compression affects 5% of all cancer patients. CANCER OF THE BREAST, LUNG AND PROSTATE account for 2/3 cases.

Symptoms

		% patients complaining	% found on examination
Central back pain ± vertebral tenderness 80%-95%	Then sudden onset of Weakness	76%	87%
	Sphincter Disturbance	0%	57%
	Sensory Deficit	51%	78%

Patients do not always complain - suspect and ask.
(Kramer JA (1992) Palliative Medicine 6 202-211)

What sort of pain?

Local bone pain in the back, particularly the thoracic spine (80%) often worse lying down, better sitting up.
Nerve root compression pain (radicular pain). Unilateral (cervical or lumbar) or bilateral (thoracic) sharp, may be jabbing or stabbing.
Cord compression pain (funicular pain) cuff or garter pain, often in kness, calves or thighs. Diffuse, cold, unpleasant sensation.

Both radicular and funicular pain is made worse by:

Flexing the neck
Straight leg raising
Coughing, sneezing or straining

This is the stage to suspect and diagnose.

Once weakness, sphincter disturbance and sensory deficit have arisen they progress rapidly. The likelihood of a good outcome from treatment reduces rapidly.

What sort of tests?

Plain x-ray of the spine has diagnostic accuracy of 80% (60% for bone scan), x-ray cervical, thoracic, lumbar spine and pelvis.

MRI scan (urgently) - is the imaging modality of choice. A normal plain X-ray and bone scan do NOT exclude malignant cord compression.

Treatment

Always indicated unless the patient is moribund.

Emergency treatment Dexamethasone

16mg over 24hrs I/V or oral
Reduced after 48-72hrs
May need sedatives as these high doses can be very excitatory
Can administer while awaiting investigation

Definitive treatment (urgent)
Surgery particularly if histology suggests non-radiotherapy sensitive tumours e.g. melanoma or spinal instability, histology is uncertain or previous radiotherapy.	Laminectomy ± radiotherapy. (Vertebrae intact)
	Anterior decompression ± radiotherapy. (Vertebrae significantly eroded)
Radiotherapy particularly if histology suggests radiotherapy sensitive tumours.

Functional Outcome

Mobility at present	% Mobile after treatment
Ambulant	50-80%
Paretic	30-40%
Paraplegic	5%
25% relapse within 6 months

Key Points

Always suspect with thoracic back pain.
Ask patient about weakness, sensory disturbance, sphincter disturbance.
Act rapidly.
Any patient with cancer is at risk

Especially cancers of breast, lung, prostate, myeloma
Especially with bony metastases
Especially with thoracic spine pain

If in doubt, discuss with the palliative care physicians or clinical oncologist.

Useful Links

Patient information on Spinal Cord Compression

North of England cancer network guidelines on spinal Cord Compression - PDF file

Lothian Palliative Care guideline on Spinal Cord Compression - PDF file

NICE guideline on metastatic spinal cord compression 2008 - PDF file