Investigations

The pertinent investigations for spinal cord and root compression are:

• general - FBC; U and E's - kidney function; LFT's - for liver metastasis
• chest X-ray
• spinal X-rays may provide evidence for cause of spinal cord compression:
  • antero-posterior:
    • erosion of pedicles suggests malignant extradural tumour
    • thinning of pedicles with increased interpedicular distance suggests chronic intradural or intramedullary expansion
  • lateral:
    • 'scalloping' of posterior surface of the vertebral body suggests chronic intradural lesion
      • narrow disc space and canal, hypertrophic joints suggests osteoarthritis / spinal stenosis
      • collapse of vertebral body suggests osteoporosis or malignant infiltration
  • oblique:
    • expansion of intervertebral foramina suggests neurofibroma
  • do not perform plain X-ray of the spine to diagnose or rule out spinal metastases or MSCC (metastatic spinal cord compression)
• MRI - investigation of choice if available; sagittal views most informative
  • perform MRI of the whole spine in patients with suspected metastatic spinal cord compression (MSCC), unless there is a specific contraindication. This should be done in time to allow definitive treatment to be planned within 1 week of the suspected diagnosis in the case of spinal pain suggestive of spinal metastases, and within 24 hours in the case of spinal pain suggestive of spinal metastases and neurological symptoms or signs suggestive of MSCC, and occasionally sooner if there is a pressing clinical need for emergency surgery
    • MRI of the spine in patients with suspected MSCC should be supervised and reported by a radiologist and should include sagittal T1 and/or short T1 inversion recovery (STIR) sequences of the whole spine, to prove or exclude the presence of spinal metastases. Sagittal T2 weighted sequences should also be performed to show the level and degree of compression of the cord or cauda equina by a soft tissue mass and to detect lesions within the cord itself. Supplementary axial imaging should be performed through any significant abnormality noted on the sagittal scan
• CT - valuable once level of lesion is known; intrathecal contrast provides most information - degree of compression and extent
  • NICE suggest that should carry out a CT scan if MRI is contraindicated, for people with suspected spinal metastases or MSCC. Rarely, if more information is needed for diagnosis and to guide management, carry out myelography after CT scanning
  • consider multiplanar viewing or 3-plane reconstruction of recent or new CT images for people with spinal metastases or MSCC to:
    • assess spinal stability and
    • plan vertebroplasty, kyphoplasty or spinal surgery
  • myelography - identifies level of lesion and site, i.e. intra-dural or extra-dural
    • consider myelography if other imaging modalities are contraindicated or inadequate. Myelography should only be undertaken at a neuroscience or spinal surgical centre because of the technical expertise required and because patients with MSCC may deteriorate following myelography and require urgent decompression
• CSF - of limited benefit - increased protein suggests a complete block; leucocytosis suggests abscess or TB; a positive Queckenstedt's test suggests complete block
  

Notes:

• NICE note that should not perform plain radiographs of the spine either to make or to exclude the diagnosis of spinal metastases or MSCC

Reference:

• 1. NICE (November 2008). Diagnosis and management of adults at risk of and with metastatic spinal cord compression.
• 2. NICE (September 2023). Spinal metastases and metastatic spinal cord compression