General
- NICE consider cauda equina compression from a metastatic source the same as spinal cord compression
Numbers
- The spine is the most common osseous site for metastatic deposits
- 40% of patients dying from cancer have spinal disease on autopsy
- Incidence: 5–8/100 000
- patients with MSCC have a poor prognosis and in a population-based study,
- 74% had died within 3 months of admission (McLinton and Hutchison, 2006)
- 20% of spine metastases represent the first presentation of the patient’s disease (Cahill, 1996)
- Investigate via
- CT TAP
- Myeloma screen
- PSA in men
- Examination of the breasts in women
Primary tumour source
- Breast cancer (16.5%)
- Lung cancer (15%)
- Prostate cancer (10%)
- Renal cell carcinoma (7%)
- 10-20% will have no known primary
- Myeloma deposits may indeed be metastatic but have been considered here with primary tumours of bone
Mechanism
- Growing tumour compromise spinal cord through
- Tumour invasion the epidural space
- causes pathological fracture of a vertebral body
- Sudden onset deficits may represent cord infarction
- a relatively poor prognosis compared to gradual onset deficit.
- Cancer inc. RANK stimulation causing osteoclastic activity
Spread
- Hematogenous spread:
- Includes venous hematogenous spread and arterial spread, spread through Batson's plexus system is the most common route, usually results in multicentric disease of the spine.
- Direct tumour extension:
- More commonly the tumour spreads backward often involving pedicles, which is an important point of understanding surgical management as screw fixation through the involved pedicles often is nonoptimal and requires extending fusion of several segments above and below the lesion.
- CSF seeding:
- Also results in multicentric disease and usually responsible for the very rare Intradural extramedullary and intramedullary metastases.
Clinical presentation
- Numbers
- 95% pain
- Local
- (periosteal stretching and inflammation, often nocturnal wakes the patient from sleep , usually deep ache, highly localizing)
- Mechanical
- (impending or established spinal instability due to deformity or collapse of vertebrae)
- Radicular
- (nerve root compression directly from tumor or narrowing of intervertebral foramen due to vertebral collapse, sharp and shooting in a specific dermatomal distribution)
- 50% not ambulant
- 20% of spine metastases represent the first presentation of the patient’s disease
- 2 types of presentation
- spinal pain only
- midline
- nocturnal
- worse on staining
- need MRI within 1 wk
- Neurological deterioration → spinal cord compression
- Radicular pain
- bladder and bowel symptoms
- weakness
- numbness
- bowel and bladder
- Anatomy
- sympathetic (hypogastric plexus)
- detrusor sensation
- parasympathetic (pudendal nerve)
- detrusor
- somatic
- Cortical control
- paracental lobule
- upper motor lesion incomplete
- no distention
- upper motor lesion complete
- Distention of bladder
- reflex arc for defecation
- disorder of bowel
- complete or partial cord lesion
- bowel atony → faecal retention
- conus lesion
- cauda equina lesion
- Sexual function
- complete / partial cord lesion
- men: loss of fertility
- priaprism
- cant ejaculate
- woman
- vaginal sensation and lubrication lost
- can still have orgasm
- fertility retained
- conus or cauda equina lesion
- loss of genital sensation
- loss of
- Sudden onset deficits may represent cord infarction and carry a relatively poor prognosis compared to gradual onset deficit.
investigation
- General
- Myeloma screen
- PSA in men
- Examination of the breasts in women
- Screening CT of the chest, abdomen, and pelvis
- MRI
- Timing NICE
- 1 week of the suspected diagnosis in the case of spinal pain suggestive of spinal metastases,
- 24 hours in the case of spinal pain suggestive of spinal metastases and neurological symptoms or signs suggestive of MSCC
- Out of hours MRI should only be performed in clinical circumstances where there is an emergency need and intention to proceed immediately to treatment, if appropriate.
- Thoracic spine the most common
- Contrast: to rule out infection (epidural abscess)
- T1
- hypo
- vertebral body expansion
- if pedicle involved generally because the posterior half vertebral body is where the Mets starts first
- T2
- hyper
- hypo in osteoblastic (prostate/osteoblastoma)
- halo
- Flair
- DWI
- Help distinguish benign and pathological compression fractures
- if cant
- CT scan
- Myelography
- Removal of fluid can worsen compression due to removal of csf
- SPECT nuclear bone scan
- provides 3D imaging of suspected vertebral metastases
- can be used to differentiate between metastatic and benign lesions.
- Nuclear scintigraphy (bone scan)
- identifying areas of increased metabolic activity throughout the skeletal system.
- They are not specific for metastatic lesions, because this activity may be related to inflammation or infection.
- 2D scan
- PET with FDG
- used for
- Whole-body surveillance in the detection of metastatic disease
- Cancer staging
- To identify cystic or necrotic areas of tumour
- assist planning of surgical intervention/biopsy to increase diagnostic yield
- Resolution of PET is limited, and correlation with CT or MR imaging is required.
- DSA
- Met secondary to primary tumours with abundant vascularity
- Eg
- Renal cell
- Thyroid
- Angiosarcoma
- Leiomyosarcoma
- Hepatocellular
- Neuroendocrine tumours
- Aim
- Gain knowledge of the vascular anatomy of metastases
- preoperative embolization of metastases
- To reduce size of tumour for patients who are not surgical candidates
- Reduces intraoperative blood loss which can
- facilitates complete resection of the lesion
- Shorten operating times
- prevent the development of postoperative hematomas which can lead to
- wound breakdown
- neurological decline.
DDX
- Osteoporotic fracture
- fluid sign on FLAIR
- vertebral haemangioma
- Modic changes
- primary bone tumours
- Discitis
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