29th December 2024

Malignant spinal cord compression (MSCC)

Overview of MSCC

Malignant spinal cord compression arises when a tumour infiltrates the spinal canal and compresses the spinal cord. It is a medical emergency that requires urgent initiation of treatment to prevent progressive neurological compromise. You should, therefore, have a high index of suspicion for MSCC in a patient with a history of cancer who presents with back pain and/or neurological signs or symptoms.

Pathophysiology of MSCC

MSCC tends to arise in tumour types that spread to or originate from bone (Table 9). It may be the first presenting feature of malignancy, particularly in tumour types that readily metastasise to bone, e.g. prostate, breast, myeloma.

Most commonly, MSCC is caused by tumour soft tissue extension into the canal space or by vertebral fractures and/or bone propulsion into the canal. Less commonly, the spinal cord may be compressed by other routes, such as progressive lymphadenopathy or extension from extradural (non bone-related) masses.

Presentation of MSCC

Pain

Back pain may precede neurological symptoms and may be constant and severe. This may be acute or subacute. In patients with known bony metastases with back pain, any sudden change in back pain should prompt investigation.

Neurological symptoms

The patient may notice any degree of weakness, sensory loss or paraesthesia in their arms (if cervical lesion) or legs (if lesion is thoracic or lower). They may describe new faecal incontinence with or without saddle anaesthesia. They may also have symptoms of urinary retention – difficulty passing urine, suprapubic pain, dribbling and overflow incontinence. These neurological symptoms are usually late signs of cord compromise.

Examination findings

In all patients presenting with suspected MSCC, it is essential to perform a full neurological examination, including a bladder scan to assess for urinary retention and a digital rectal examination to assess anal tone. Regular neurological examinations should be performed thereafter to monitor for any neurological deterioration.

On examination, there may be point tenderness on palpation of a vertebra overlying the compressive lesion.

There may be a pattern of complete or incomplete spinal cord neurological compromise. If complete, there will be a sensory level just below the level of compression, and below this there will be complete sensory loss and an upper motor neuron pattern of weakness. This would also be accompanied by bowel and bladder dysfunction.

The spinal cord ends at L1-2, and lesions below this may compress the cauda equina. This would characteristically result in sciatic pain, sexual dysfunction, urinary retention, saddle anaesthesia and loss of anal tone.

Investigation of MSCC

The gold standard investigation is an MRI of the whole spine, which should be performed within 24 hours of presentation. Even where there are localising signs, the whole spine should be imaged as there may be other sites of cord compression (or impending compression) above or below the symptomatic lesion.

In 15-20% of cases there may be no abnormalities on a plain X-ray, and this should not be used to rule out MSCC.

In addition, CT imaging of the spine may be considered, to guide decisions on bony stability and surgical options.

In cases where MRI is contraindicated or unavailable, CT may be considered with or without concurrent myelography. This should be performed only in specialist centres, as myelography may cause neurological deterioration, requiring urgent decompression.

Management of MSCC

Swift action is required when MSCC is suspected, to prevent further neurological decline. Treatment involves high-dose corticosteroids, ensuring spinal stability, and definitive treatment with surgery or radiotherapy (Table 10).

Corticosteroids

Immediate treatment with high-dose corticosteroids reduces perilesional oedema and should be initiated prior to confirmation of MSCC with imaging.  The steroid of choice is dexamethasone, initially 16 mg stat. Ongoing dosing may be 16 mg OD (once daily) or 8 mg BD (twice daily) (8am and noon).

Thought should be given to co-prescription of gastroprotection (e.g. proton pump inhibitors such as omeprazole) and, in the longer term, bone protection with bisphosphonates and calcium supplementation. In breast cancer and myeloma with vertebral deposits, bisphosphonates should be started empirically to help with pain and stability.

Spinal surgery versus radiotherapy

Urgent discussion with the clinical oncology MSCC coordinator and neurosurgical team should follow. In confirmed MSCC, the optimal treatment is surgery (decompression of the cord and spinal fixation/stabilisation) followed by postoperative radiotherapy after surgical healing is complete.

Suitability for surgery depends on the following:

• The patient being fit enough for surgery
• An operation being technically possible
• Predicted prognosis from the underlying tumour likely to outlast operative recovery
• Prospect of neurological recovery; good chance if paralysis is acute onset (< 24-48 hours)
• In cases where MSCC is the presenting complaint, resection may provide a biopsy for tissue diagnosis
• Radioresistant tumour type or progression or relapse of MSCC after previous radiotherapy
• Patient choice or preference

Where spinal surgery is not possible, the patient should be considered for urgent (within 24 hours) radiotherapy.

After surgery and radiotherapy, high-dose dexamethasone can be weaned slowly.

Spinal stability

Spinal stability must also be considered; tumour burden, vertebral fractures and bone retropulsion may cause further cord compression with spinal movement. Until stability is confirmed, the patient should be nursed with full spinal precautions with flat bed rest and log-roll technique when repositioning.

If the spine is deemed unstable and spinal fixation is not appropriate or the patient is experiencing significant pain, the neurosurgical team may advise the use of external supports, collars or braces.

Supportive treatment

If there is pain, appropriate analgesia should be provided.

Patients are at high risk of venous thromboembolism due to malignancy and immobility, and appropriate prophylaxis should be prescribed – ideally prophylactic-dose low molecular weight heparin and compression stockings.

Bowel and bladder function should be monitored, with urgent catheterisation for urinary retention and bowel management systems considered for faecal incontinence. Prevent pressure sores with regular repositioning.

If there is significant neurological impairment, rehabilitation and appropriate discharge planning are paramount.

References

• Cassidy J, Bissett D, Spence RAJ, Payne M, Morris-Stiff GJ. Oxford Handbook of Oncology. 4th ed. Oxford: Oxford University Press; 2015
• National Institute for Health and Clinical Excellence. Metastatic spinal cord compression in adults [Internet]. NICE. 2008 [cited 2022 Apr 17]. Available from: https://www.nice.org.uk/guidance/cg75
• Patchell RA, Tibbs PA, Regine WF, Payne R, Saris S, Kryscio RJ, et al. Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial. The Lancet. 2005 Aug;366(9486):643–8