Spinal Cord Compression

Meet the patient

A 68-year-old woman with known breast cancer develops three weeks of progressive mid-back pain that is worse at night and worse lying flat, then two days of heaviness in both legs and difficulty climbing stairs. On examination she has a sensory level at T6, brisk knee and ankle reflexes, extensor plantars, and normal fundi. She can still walk, but only just.[1]

A different patient — a 34-year-old man — presents to the emergency department at 2 am with severe lower-back pain radiating down both legs, numbness around his genitals and buttocks, and an inability to pass urine since that morning. These are two faces of the same emergency, and the rule that governs both is the same: the early, oedematous phase of compression is reversible; the late, infarcted phase is not. Every minute from the first neurological deficit to decompression is nerve tissue that may never recover. Time is cord.[1][8]

What cord compression is — and why the clock governs everything

Spinal cord compression is one of the few true neurological emergencies in which hours, not days, decide whether a patient walks or is paralysed for life. The discipline is to recognise the pattern — progressive back pain plus a neurological deficit — to image urgently with whole-spine MRI rather than CT, to give dexamethasone immediately when the cause is malignant, and to decompress within 24 to 48 hours by surgery or radiotherapy. The most important single clinical sign is bladder dysfunction: once painless urinary retention appears, the window for neurological recovery is closing rapidly.[1][2]

Spinal cord compression is any pathological process that compromises the neural tissue of the cord, the conus medullaris, or the cauda equina within the spinal canal, producing progressive neurological deficit below the level of the lesion. By the time the syndrome is clinically recognisable, the compressing mass — tumour, disc, pus, blood or bone — has already begun the cascade of venous congestion, oedema and ischaemia that, left untreated, terminates in irreversible cord infarction. The early, oedematous phase is pharmacologically and surgically reversible; the late, infarcted phase is not. That biological clock is the reason every guideline treats this as an emergency.[2]

The terms, used precisely

Several overlapping terms appear in the literature and in exam stems, and a candidate must use them precisely. Spinal cord compression is the umbrella clinical syndrome. Malignant spinal cord compression (MSCC) — also called metastatic epidural spinal cord compression (MESCC) when the tumour lies in the epidural space — refers specifically to compression by metastatic cancer, the commonest cause overall and the entity to which the dexamethasone-and-radiotherapy pathway applies.[1][6] Cauda equina syndrome (CES) is compression of the lumbosacral nerve roots below the conus (the cord ends at L1 to L2), producing a lower motor neurone pattern with saddle anaesthesia, retention and areflexia — a different operation and a different urgency.[8]

Classification — level, tempo, cause

Spinal cord compression is classified along three axes that together determine the urgency, the operation and the prognosis. By anatomical level it divides into compression above the conus (true cord compression, UMN signs and a sensory level), at the conus medullaris (mixed UMN and LMN with early sphincter involvement), and below the conus (cauda equina, LMN signs with saddle anaesthesia). By tempo: acute (hours to days — trauma, epidural haematoma, abscess), subacute (days to weeks — typical of malignant compression), or chronic (months — degenerative canal stenosis, slow-growing intradural tumours). By aetiology: neoplastic, degenerative and mechanical, infective, vascular or traumatic.[1]

For malignant epidural disease, radiologists and spine surgeons use the Bilsky epidural spinal cord compression (ESCC) grading scale, a six-point scale grading epidural tumour and cord deformation on axial MRI. Grade 0 is bone-only disease; grade 1 is epidural tumour abutting but not deforming the cord; grade 2 is cord displacement or compression without CSF block; grade 3 is cord compression with a complete CSF block and cord deformation. High-grade (2 and 3) compression, an unstable spine, or a radio-resistant tumour favour surgical decompression.[1]

[1]

How common, and who

Malignant spinal cord compression is overwhelmingly a disease of advanced cancer and one of its most devastating complications. Approximately 5 to 10 percent of all cancer patients develop clinically evident MSCC at some point, rising to as much as 10 percent in myeloma and prostate cancer. In the United Kingdom, MSCC is the second commonest neurological complication of cancer after brain metastasis, with an estimated annual incidence of around 40 to 80 cases per million. The mean age at presentation is the seventh decade, reflecting the age distribution of the common primary tumours.[1][5]

The five commonest primary tumours responsible for MSCC, in rough order, are breast, prostate, lung, myeloma or lymphoma, and kidney (renal cell) carcinoma — together over three-quarters of cases. A useful mnemonic that also captures relative frequencies is BLPT-RK: Breast, Lung, Prostate, Thyroid or myeloma, Renal, Kidney. The thoracic spine is the commonest site of metastatic cord compression (around 60 to 70 percent of cases), because it has the most vertebrae and the narrowest canal; the lumbosacral region follows, then the cervical. Prostate cancer has a particular tendency to seed the lumbosacral spine via Batson's venous plexus.[1]

The risk factors for non-malignant compression differ by cause. For spinal epidural abscess, they are intravenous drug use, diabetes mellitus, immunosuppression (including HIV and chronic steroids), bacteraemia or endocarditis, recent spinal procedure or epidural injection, indwelling vascular catheters, and alcohol misuse; Staphylococcus aureus is the causative organism in over half.[7] For cauda equina syndrome from disc herniation, the principal risk factors are a large central or paracentral disc protrusion, older age, heavy occupational loading, and acute trauma on pre-existing degenerative disease. For epidural haematoma, the dominant risk factor is iatrogenic or therapeutic anticoagulation.[1]

Why the cord dies — the compression cascade

The cord is destroyed in a cascade, and the entire clinical urgency flows from a single biological fact: the early stages of compression are reversible, while the late stages are not. This is why time is cord.[1]

Stage one — mechanical deformation. The tumour, disc, abscess, haematoma or bone fragment physically distorts the cord or nerve roots and raises the pressure within the spinal canal. Stage two — venous congestion and vasogenic oedema. Obstruction of the epidural venous plexus produces venous hypertension, capillary leakage and vasogenic oedema, visible on MRI as T2 hyperintensity within the cord. This stage is still reversible — and it is the target of dexamethasone. Stage three — arterial ischaemia and demyelination. Compromise of the arterial supply produces ischaemia and demyelination, with worsening but still potentially salvageable deficit. Stage four — axonal infarction and necrosis. Irreversible. The deficit is now permanent.[1]

Why specific tracts fail in a specific order

The arterial supply explains both the watershed vulnerability and the tract-selective pattern. The cord is supplied by a single anterior spinal artery (derived from the vertebrals, reinforced by segmental medullary arteries, most importantly the artery of Adamkiewicz, which usually enters on the left between T9 and L2) and the paired posterior spinal arteries. The anterior spinal artery perfuses the anterior two-thirds — the corticospinal (motor) and spinothalamic (pain and temperature) tracts and the anterior horns — while the posterior arteries perfuse the posterior third, including the dorsal columns. Because compression compromises the more vulnerable anterior supply first, motor and pain-temperature loss precede proprioceptive loss, and the watershed zone around T4 to T8 is the most ischaemia-vulnerable segment.[1]

The causes — four aetiologic groups

The four broad groups are neoplastic, degenerative and mechanical, infective, and vascular or traumatic. Metastatic cancer is the single commonest cause overall. Metastatic tumour reaches the epidural space most often by haematogenous spread to the vertebral body, then contiguous extension through the posterior vertebral cortex into the anterior epidural space — which is why the typical compressing mass is anterior and decompressive surgery often involves a lateral or posterior approach with vertebral-body resection (corpectomy) and stabilisation.[1]

The commonest cause of acute cauda equina syndrome is a large central or paracentral lumbar disc herniation, typically at L4 to L5 or L5 to S1. Degenerative lumbar canal stenosis produces neurogenic claudication (leg pain, heaviness and paraesthesia brought on by walking and relieved by sitting or spinal flexion) rather than true cord compression; the absence of saddle anaesthesia, retention, or a motor level distinguishes claudication from CES.[8]

Spinal epidural abscess is the prototypical infective cause: a collection of pus in the epidural space, most often from haematogenous spread or contiguous infection (vertebral osteomyelitis, discitis, psoas abscess). Pott's spine (tuberculous spondylodiscitis) merits separate attention in high-burden settings: Mycobacterium tuberculosis seeds the lower thoracic and upper lumbar spine, producing subacute destructive spondylodiscitis with anterior vertebral-body collapse, kyphotic deformity (the classic Pott's gibbus) and an anterior epidural abscess compressing the cord.[7]

Meet the compression at the bedside — pain, deficit, autonomic failure

The presentation is dominated by three cardinal features — pain, neurological deficit, and autonomic dysfunction — whose tempo and pattern localise the lesion and time the emergency. Back pain is the first and most constant symptom, present in approximately 95 percent of MSCC at presentation and often preceding neurological deficit by days to weeks. The pain of malignant compression is characteristically progressive, worse at night, and unrelieved by rest — the inverse of mechanical back pain, which is worse with activity and relieved by lying down.[1]

Below the level of a true cord compression, the motor examination reveals progressive UMN weakness — initially heaviness, stiffness and difficulty climbing stairs, evolving to overt paraparesis or tetraparesis. The weakness is typically symmetric for cord lesions (in contrast to the asymmetric, radicular weakness of cauda equina). Tone is increased, deep tendon reflexes are brisk, and the plantar responses are extensor (Babinski); clonus may be present at the ankles. Sensory examination reveals a sensory level — a horizontal line on the trunk below which pinprick and temperature is lost — which is the single most useful clinical sign for localising the lesion.[1]

Autonomic dysfunction is a late and ominous feature. The earliest autonomic sign is urinary retention with overflow incontinence — the bladder becomes palpable, the patient describes passing small volumes or dribbling, and a post-void residual is markedly raised. Faecal incontinence from anal sphincter denervation, erectile dysfunction, and reduced anal sphincter tone follow. The appearance of sphincter disturbance signals that the damage has reached the conus or sacral roots and that the window for neurological recovery is closing; once complete retention is established, the prognosis for bladder recovery is poor even after decompression.[1]

The reflex pattern is a high-yield discriminator. In true cord compression above the conus, reflexes below the lesion are brisk with clonus and extensor plantars. In cauda equina, by contrast, reflexes below the lesion are depressed or absent — specifically the ankle jerks (S1 to S2) and often the knee jerks (L3 to L4) — and the plantars are flexor; the weakness is flaccid. The spinal epidural abscess classically presents with a triad of severe back pain, fever, and progressive neurological deficit — although only a minority have all three at first presentation, which is why the absence of fever never excludes it.[7]

Cauda equina syndrome — the commonest acute spinal emergency on call

Cauda equina syndrome deserves dedicated attention because it is the commonest acute spinal emergency a junior doctor will encounter on call, because its recognition is time-critical, and because its medicolegal consequences when missed are severe. The cauda equina ('horse's tail') is the leash of lumbosacral nerve roots below the conus medullaris, which marks the caudal end of the cord at approximately the L1 to L2 vertebral level in adults. Compression — most often by a large central lumbar disc herniation at L4 to L5 or L5 to S1 — produces a characteristic picture every final-professional candidate must recite.[8]

The four cardinal features of cauda equina syndrome are: saddle anaesthesia (loss of sensation over the perineum, buttocks, posterior thighs and genitalia — the dermatomes of S2 to S4, which contact the saddle in a rider); bilateral sciatica or bilateral radicular leg pain; bladder dysfunction (urinary retention, incontinence, or loss of urethral sensation); and bowel and sexual dysfunction (faecal incontinence, reduced anal tone, erectile dysfunction). To these are added the lower motor neurone signs of flaccid weakness, hypotonia and areflexia, and a markedly raised post-void residual volume. The rectal examination is the key bedside investigation: reduced anal sphincter tone, absent anal wink, and perianal numbness confirm the syndrome.[8]

CES-R versus CES-I — the timing distinction

A clinically important subclassification, increasingly used in guidelines and emphasised in the Lavy consensus, distinguishes cauda equina syndrome with retention (CES-R) — the complete syndrome with painless urinary retention and overflow incontinence, a palpable bladder and a post-void residual well above 200 mL — from cauda equina syndrome incomplete (CES-I), in which the patient has bilateral neurological symptoms and signs (saddle anaesthesia, bilateral sciatica, motor or sensory deficit) but voluntary bladder control is preserved and retention is not yet established.[8]

The distinction matters because CES-I is the urgent window: a patient with CES-I can still recover full bladder and motor function if decompressed promptly, whereas once retention is established (CES-R) the chance of a continent bladder falls steeply even with prompt surgery. Decompress CES-I as urgently as CES-R to prevent progression to a permanent neurogenic bladder.[8]

The post-void residual (PVR) is quantified by bladder ultrasound or catheterisation: a residual above 100 to 200 mL in the setting of suspected cauda equina is abnormal and requires urgent imaging; residual above 500 mL with a palpable bladder is consistent with established retention and full CES-R. New bilateral sciatica, new urinary symptoms, or any saddle sensory disturbance in a patient with back pain must trigger urgent MRI within hours, not days.[8]

Cord, conus and cauda — the face-off

The three compressive syndromes of the thoracolumbar spine must be distinguished at the bedside, because each carries a different urgency, a different operation, and a different prognosis.[2][8]

[2] [8]

The discriminator line: cord above the conus gives brisk reflexes and a sensory level with late sphincter loss; cauda below the conus gives areflexia, saddle anaesthesia and early severe retention; conus gives a mix with the earliest and worst sphincter involvement.[8]

The bedside assessment — localise, then image

A focused but complete neurological examination is required whenever cord compression is suspected — both to confirm the syndrome and to localise the level, which directs the MRI and the surgical approach. The examination has four components: motor, sensory, reflex, and autonomic (sphincter). Motor documents tone, power (MRC grade 0 to 5 in each myotome), and the distribution of weakness. Sensory maps pinprick and light touch on each dermatome to identify a sensory level — the single most reliable bedside localising sign. Reflex documents the pattern. Autonomic includes the rectal examination — anal tone, anal wink, bulbocavernosus reflex, and perianal sensation — and a bedside bladder scan for post-void residual.[1]

The named signs and manoeuvres examined here include the Babinski sign, ankle clonus, the Lhermitte sign (electric-shock sensation down the spine on neck flexion — classically in MS but also in cervical cord compression), and the anal wink (contraction of the external anal sphincter on pricking the perianal skin, reflecting S2 to S4 integrity; its absence indicates sacral root or conus involvement). The bulbocavernosus reflex — contraction of the bulbocavernosus on squeezing the glans or tugging the urinary catheter — tests S2 to S4 integrity; its return after spinal shock marks the end of the acute phase in traumatic injury.[1]

A general examination often reveals the underlying cause: cachexia, a mastectomy scar, a prostate or breast mass, lymphadenopathy, stigmata of intravenous drug use, fever and a heart murmur suggesting endocarditis, or the bruising of anticoagulation. The candidate who presents the examination by system, then level, then likely cause, then urgency — and explicitly states the bladder and sphincter findings — covers every domain an examiner marks.[1]

The differential — exclude the compressive lesion first

A compressive lesion must be excluded first: every patient with a possible sensory level or progressive leg weakness gets an urgent whole-spine MRI before any other diagnosis is entertained, because the cost of missing a decompressible cord lesion is permanent paraplegia. Once imaging excludes compression, the differential of a subacute myelopathy or progressive leg weakness opens up.[1][2]

[1] [2]

Investigations — one imperative test

The investigation of suspected cord compression has one imperative test, several adjunctive blood tests for aetiology, and one bedside test for cauda equina. The imperative test is urgent whole-spine magnetic resonance imaging (MRI) — the gold standard and the only imaging modality that reliably demonstrates the cord, the cauda equina roots, the compressing mass, and the cord signal change that predicts prognosis. A protocol of sagittal and axial T1 and T2 sequences, with gadolinium if an abscess, a primary tumour or leptomeningeal disease is suspected, demonstrates the level, the cause and the cord signal change in a single study. Whole-spine rather than limited imaging is required because metastatic disease is often multisegmental.[1]

Plain CT of the spine shows bone beautifully but cannot assess the cord, the roots, or the soft-tissue mass, and is therefore insufficient to exclude cord compression — a fact the examiner tests repeatedly. CT is valuable for assessing vertebral-body destruction, fracture and instability, and is used in surgical planning. CT myelography is the alternative when MRI is contraindicated (a non-MRI-compatible pacemaker, certain aneurysm clips, cochlear implants, severe claustrophobia). Plain radiographs are insensitive and have no role in excluding cord compression.[1]

Blood tests and the bedside bladder scan

Blood tests serve three purposes: to identify the cause, to assess fitness for intervention, and to monitor for complications. The panel for suspected malignant compression includes full blood count (anaemia of chronic disease, leucoerythroblastic picture in marrow infiltration), ESR and CRP (raised in infection, malignancy and inflammation — a near-obligate finding in epidural abscess), renal function and electrolytes (dehydration, hypercalcaemia), liver function and albumin, coagulation screen, serum calcium and albumin (hypercalcaemia of malignancy, myeloma), PSA in men if prostate cancer is possible, and a myeloma screen — serum protein electrophoresis, serum free light chains and urine Bence-Jones protein.[1]

The bedside bladder scan — a portable ultrasound measurement of bladder volume after attempted micturition — is the practical test for cauda equina. A post-void residual above 100 mL raises concern, above 200 mL is significantly abnormal, and above 500 mL with a palpable bladder and overflow incontinence is consistent with established retention (CES-R). Cerebrospinal fluid analysis (lumbar puncture) has essentially no role in suspected acute cord compression: a lumbar puncture below a complete spinal block can precipitate neurological deterioration, and it is contraindicated until imaging has excluded a compressive lesion.[1]

[1] [8]

The emergency bundle — recognise, protect, image, steroid, refer

[1]

The immediate management of suspected cord compression is a time-critical bundle that should begin the moment the syndrome is recognised, in parallel with — not after — arranging the MRI. The bundle has six components: recognise and protect, image, steroid, analgesia, nursing and bladder care, and refer.[1][6]

Recognise and protect. The diagnosis is made clinically; it should not await imaging. The patient is nursed flat with log-rolling for all movements to avoid displacing an unstable spine (especially in traumatic or destructive malignant collapse), and strict pressure-area care is begun immediately — paralysed or weak patients develop pressure ulcers within hours. Vital signs, cardiac monitoring, and intravenous access are established; cervical and high thoracic lesions can cause autonomic instability and respiratory compromise.[1]

Image. Arrange urgent whole-spine MRI — within 24 hours of suspicion for MSCC (NICE NG12 standard), and within hours for cauda equina syndrome, rapidly progressive deficit, or suspected epidural abscess or haematoma. While the MRI is arranged, take the bloods and a bladder-scan reading.[1]

Steroid. For malignant spinal cord compression, give dexamethasone 16 mg as a loading dose intravenously (or orally) immediately, followed by a maintenance regimen of 16 mg per day (commonly 8 mg twice daily, then taper) — the goal is to reduce vasogenic cord oedema, relieve pain and protect the cord from ischaemic injury during the wait for definitive decompression. Steroids are not routinely given for cauda equina of disc origin (no proven benefit and possible harm), nor as standard for epidural abscess or haematoma.[1]

Analgesia, nursing and bladder care, and refer. Give analgesia following the WHO ladder, escalating from paracetamol and an NSAID (if not contraindicated) to a weak then a strong opioid; for neuropathic or radicular pain add gabapentin or pregabalin. Insert a urinary catheter for established retention, and institute venous thromboembolism prophylaxis because the immobile cancer patient is at very high risk of DVT and pulmonary embolism. Finally, refer urgently to the spinal surgery and oncology teams via the MSCC or cauda equina pathway.[1]

[1]

Definitive treatment — surgery versus radiotherapy for MSCC

The definitive treatment of malignant spinal cord compression is a choice between direct decompressive surgery followed by radiotherapy and radiotherapy alone, made by the multidisciplinary team on the basis of performance status, the number of compressive levels, the tumour's radiosensitivity, spinal instability, prognosis, and the patient's wishes. The framework the modern decision rests on is the landmark randomised trial of Patchell and colleagues (2005).[3][1]

The Patchell trial and what it changed

Patchell and colleagues randomised 101 patients with a single level of metastatic cord compression to either direct decompressive surgical resection followed by radiotherapy (30 Gy in 10 fractions) within 14 days or radiotherapy alone. The trial was closed early at interim analysis because of a clear benefit of surgery: significantly more patients in the surgery arm remained ambulatory or regained ambulation (84 percent versus 57 percent), more regained the ability to walk after losing it (62 percent versus 19 percent), surgery patients retained the ability to walk for longer, and they had a significantly longer median survival (126 days versus 100 days). The trial established that, for the single-level, fit patient with metastatic cord compression, direct decompressive surgery plus radiotherapy is superior to radiotherapy alone.[3]

Indications for surgery and for radiotherapy

The indications for surgical decompression (with or without instrumented stabilisation) in MSCC are: a single level of compression in a fit patient; spinal instability or a retropulsed bone fragment; an unknown primary tumour for which histology is needed; a radio-resistant tumour (renal cell carcinoma, melanoma, sarcoma, some non-small-cell lung cancers); recurrence after prior radiotherapy; or neurological deterioration during or after radiotherapy. The indications for radiotherapy alone are: multiple compressive levels; a radiosensitive tumour (breast, prostate, myeloma, lymphoma, small-cell lung cancer); a patient unfit for surgery; or a very poor projected survival.[1]

The radiotherapy fractionation schedules in common use are 8 Gy in a single fraction (the commonest palliative regimen, providing rapid pain relief and equivalent ambulation to longer courses in patients with short prognosis), 20 Gy in 5 fractions, or 30 Gy in 10 fractions (used for better-prognosis patients and radiosensitive tumours).[5]

Cauda equina, abscess and haematoma — the definitive treatments

For cauda equina syndrome from a large central lumbar disc herniation, the definitive treatment is emergency surgical decompression — microdiscectomy, hemilaminectomy or laminectomy — within 24 to 48 hours of the onset of complete retention; the goal is to relieve root compression before irreversible root infarction. Steroids are not routinely given for cauda equina of disc origin (no proven benefit and possible harm). Decompression within 48 hours is associated with markedly better motor, bladder and sensory recovery than decompression after 48 hours of complete paralysis.[8]

For spinal epidural abscess, definitive treatment combines urgent surgical decompression with prolonged intravenous antibiotics directed at the cultured organism for 4 to 6 weeks. Empiric therapy before culture must cover Staphylococcus aureus (including MRSA) and Gram-negatives; a typical regimen is IV vancomycin plus a third-generation cephalosporin such as ceftriaxone (or vancomycin plus piperacillin-tazobactam if Pseudomonas is likely). Selected patients with small abscesses, no neurological deficit and a surgically-correctable source may be managed with antibiotics alone under close observation.[7]

For epidural haematoma, definitive treatment is urgent surgical evacuation with reversal of anticoagulation (vitamin K and prothrombin complex concentrate for warfarin; specific reversal agents for the direct oral anticoagulants). The window for neurological recovery is the same — within 24 to 48 hours for the best outcome. For Pott's spine with neurological deficit, severe kyphosis or instability, treatment combines prolonged anti-tubercular therapy (the standard four-drug regimen: isoniazid, rifampicin, pyrazinamide, ethambutol for two months, then isoniazid and rifampicin for at least seven more months) with surgical decompression and stabilisation.[1]

The subtypes and scenarios that change the operation

Traumatic cord injury and the NASCIS controversy. In traumatic spinal cord injury with persistent cord compression by bone fragment or haematoma, urgent surgical decompression and stabilisation is performed once the patient is resuscitated. The NASCIS-2 and NASCIS-3 trials examined high-dose intravenous methylprednisolone given within 8 hours of injury — the NASCIS-3 regimen being a 30 mg/kg IV bolus over 15 minutes, followed after a 45-minute pause by a 5.4 mg/kg/hour infusion for 23 hours (or for 48 hours in selected patients). The trials reported a modest neurological benefit in subgroup analyses, but the magnitude and clinical meaningfulness of that benefit, and the risks (infection, gastrointestinal bleeding), remain contentious; high-dose methylprednisolone is not a standard of care and is used selectively, if at all, in many centres.[4]

Cervical cord compression is more dangerous than thoracic or lumbar for three reasons: the cervical cord carries the pathways to all four limbs (quadriparesis rather than paraparesis); high cervical lesions (above C5) compromise the phrenic nerve roots (C3 to C5) and the diaphragm, producing respiratory failure; and the cervical sympathetic outflow traverses this segment, so high lesions can produce Horner syndrome, autonomic instability and neurogenic shock (hypotension with bradycardia from loss of sympathetic tone).[1]

Pregnancy, age and the immunocompromised. In pregnancy, the same urgency applies but MRI can be performed safely (without gadolinium) in any trimester; the patient is positioned in the left lateral decubitus position to avoid aortocaval compression, and a multidisciplinary plan addresses the timing of delivery relative to decompression. In the elderly, degenerative cervical myelopathy — chronic cord compression from cervical spondylosis and ligamentum-flavum hypertrophy — is the commonest cause of non-traumatic myelopathy in older adults, presenting with hand clumsiness, gait disturbance and UMN signs in the legs.[1]

Complications and rehabilitation

The complications divide into those caused by delayed decompression and those caused by the resulting immobility and neurological deficit. The principal disease complication is permanent paraplegia or quadriplegia — the direct consequence of cord infarction from delayed decompression — with permanent bladder and bowel dysfunction from sacral cord or cauda equina damage, and chronic neuropathic pain below the compression level. Spasticity develops below the lesion in the weeks after injury.[1]

The complications of immobility must be prevented aggressively from the day of admission: pressure ulcers (turn every two hours, pressure-relieving mattress); deep-vein thrombosis and pulmonary embolism (mechanical and pharmacological prophylaxis); urinary tract infection from catheterisation (use intermittent catheterisation where possible); contractures (passive range-of-movement exercises); pneumonia (deep-breathing exercises, incentive spirometry); and constipation and faecal impaction.[1]

Rehabilitation begins from the day of admission, not after discharge: early physiotherapy for chest, joint range and strength; occupational therapy for activities of daily living and home modification; bladder and bowel retraining (intermittent self-catheterisation, a structured bowel programme); psychological support; and a coordinated discharge plan involving the community spinal-cord-injury or rehabilitation team. Patients with significant residual deficit are best managed through a regional spinal injuries or rehabilitation centre.[1]

Prognosis — the strongest predictor is what they could do before treatment

The single strongest predictor of post-treatment ambulatory outcome in malignant spinal cord compression is the pre-treatment ambulatory status — replicated across every cohort and trial. Patients walking before treatment overwhelmingly remain ambulatory after treatment (around 80 to 90 percent); patients non-ambulatory but with some motor function may regain ambulation in roughly 30 to 60 percent; patients completely paraplegic before treatment rarely regain ambulation (under 10 percent). The duration and severity of the deficit before treatment also matter: a deficit of less than 24 to 48 hours carries a far better outlook than one of a week or more.[1]

The median survival after a diagnosis of malignant spinal cord compression is approximately 3 to 6 months, varying markedly with the primary tumour (prostate and breast cancer patients often survive a year or more; lung cancer patients a few months; myeloma patients variable) and with performance status and burden of visceral metastases. This median survival is the reason the treatment decision must weigh the burden of surgery against the projected benefit in remaining life.[1]

For cauda equina syndrome from disc herniation, decompression within 48 hours is associated with markedly better motor, sensory and bladder recovery than decompression after 48 hours of complete paralysis. The recovery of bladder function is strongly time-dependent: patients decompressed within 24 to 48 hours often regain a continent bladder, while those decompressed late frequently have a permanent neurogenic bladder requiring lifelong intermittent catheterisation. The risk of permanent bladder and bowel dysfunction once established retention has occurred is substantial even with prompt surgery, which is why preventing progression from CES-I to CES-R is the single most impactful clinical decision in the pathway.[8]

Prevention, screening and oncology follow-up

Because the outcome is so dependent on pre-treatment neurological status, early recognition before neurological deficit develops is the single most effective intervention. Two strategies are central. The first is patient and primary-care education: every patient with a cancer that has a high propensity for spinal metastasis (breast, prostate, lung, myeloma, kidney) should be told, in writing and verbally, the red-flag features of incipient cord compression — new or progressive back pain, night pain, radicular pain, limb weakness, numbness, difficulty walking — and instructed to present urgently. The second is a low threshold for proactive spinal MRI in patients with high-risk cancer and new back pain.[1]

Bone-modifying agents have a specific preventive role. Bisphosphonates (zoledronic acid, pamidronate) and the RANKL inhibitor denosumab reduce the rate of skeletal-related events — pathologic fracture, spinal cord compression, the need for radiotherapy or surgery to bone, and malignant hypercalcaemia — in patients with bone metastases from breast, prostate, myeloma and other solid tumours.[1]

The medicolegal importance of acting on red-flag back pain cannot be overstated. Missed or delayed cauda equina syndrome is one of the commonest and most costly sources of medical negligence litigation. The legal duty is to document the presence or absence of red flags explicitly, to perform and record the neurological and rectal examination, to arrange urgent imaging and refer within the recommended timeframe, and to communicate clearly with the patient about the warning signs and when to return.[8]

Evidence, guidelines and regional deltas

Spinal cord compression sits at the intersection of neurology, oncology, spinal surgery, infectious diseases and emergency medicine. The United Kingdom NICE NG12 guideline and the Spinal Cord Impairment pathway standardise the cancer-back-pain referral and the 24-hour MRI standard for suspected MSCC. In the United States, the AANS/CNS guidelines endorse direct decompressive surgery plus radiotherapy for single-level MSCC in the fit patient (Patchell framework), with radiotherapy alone for multiple levels, radiosensitive tumours or unfit patients.[1][3]

The dexamethasone evidence remains the most contentious element. The standard 16 mg loading dose derives from observational series and the systematic review by Loblaw and colleagues (2005); no large modern randomised trial has established the optimal corticosteroid regimen, and some centres have moved to a lower routine dose (for example 8 to 10 mg loading) on the grounds that the higher-dose evidence is observational and the side-effect burden is dose-dependent. The 16 mg dose remains the widely cited standard and the dose a candidate should state in an exam.[5]

The radiotherapy fractionation debate has been largely settled by randomised trials showing that 8 Gy in a single fraction is equivalent to longer fractionation for pain control and ambulation in patients with short prognosis, although retreatment is more often needed after single-fraction treatment.[5]

[1] [1] [3] [1]

The mnemonics, and the mantra

[1] [1] [1]

The mantra: time is cord — dexamethasone 16 mg for malignant compression, whole-spine MRI, decompress within 24 to 48 hours; cauda equina gets surgery and no steroids; pre-treatment ambulatory status is the strongest predictor of outcome; decompress CES-I as urgently as CES-R.[1][8]

[1] [3] [8]

Ward-round test — three stems, thirty seconds each

Stem 1 — the woman with breast cancer and a sensory level (answer)

A 68-year-old with known breast cancer has three weeks of progressive nocturnal mid-back pain, then two days of bilateral leg heaviness. Examination shows a sensory level at T6, brisk reflexes and extensor plantars. She can still walk. What is the diagnosis, the first drug, the imperative test, and the definitive treatment? Model: This is malignant spinal cord compression at the thoracic level. Give dexamethasone 16 mg IV immediately to reduce vasogenic cord oedema. Order urgent whole-spine MRI within 24 hours (CT is insufficient — it shows bone, not cord). Then decompress within 24 to 48 hours — by the Patchell framework, direct decompressive surgery plus radiotherapy (30 Gy in 10 fractions) is superior to radiotherapy alone for single-level disease in a fit patient; radiotherapy alone is chosen for multiple levels, a radiosensitive tumour, or an unfit patient. Her pre-treatment ability to walk is the strongest predictor that she will remain ambulatory — act now.[1][3]

Stem 2 — saddle anaesthesia and retention at 2 am (answer)

A 34-year-old man presents with severe lower-back pain radiating down both legs, numbness around his genitals and buttocks, and inability to pass urine since the morning. Examination shows reduced anal tone, absent ankle jerks, saddle anaesthesia, and a palpable bladder. What is the syndrome, the bedside test, the imperative investigation, and the treatment — and is there a role for steroids? Model: This is cauda equina syndrome with retention (CES-R) from a presumptive large central lumbar disc herniation. The bedside test is a bladder scan for post-void residual (above 200 mL significantly abnormal; above 500 mL with a palpable bladder is established retention). The imperative investigation is urgent whole-spine MRI with lumbar emphasis within hours. The treatment is emergency surgical decompression — microdiscectomy or laminectomy within 24 to 48 hours. There is no role for routine steroids in cauda equina of disc origin — no proven benefit and possible harm. Document the neurological and rectal findings explicitly; missed cauda equina is one of the commonest sources of medical negligence litigation.[8]

Stem 3 — back pain, fever and a rapidly rising ESR (answer)

A 55-year-old with diabetes and recent intravenous drug use has five days of severe back pain, fever, and progressive leg weakness. ESR is 110, CRP 280. What is the likely diagnosis, the organism, the imaging, and the treatment? Model: This is spinal epidural abscess until proven otherwise — the triad of severe back pain, fever and progressive neurological deficit (though all three are present in only a minority at first presentation). The likely organism is Staphylococcus aureus (over half of cases, including MRSA in at-risk groups). The imaging is urgent whole-spine MRI with gadolinium (rim-enhancing collection with central low signal and surrounding phlegmon). The treatment combines urgent surgical decompression with prolonged intravenous antibiotics for 4 to 6 weeks — empirically vancomycin plus a third-generation cephalosporin (ceftriaxone), or vancomycin plus piperacillin-tazobactam if Gram-negatives including Pseudomonas are likely. Do not delay decompression for culture results in a patient with neurological deficit.[7]

References

1. [1]Lawton AJ, Lee KA, Cheville AL, et al. Assessment and Management of Patients With Metastatic Spinal Cord Compression: A Multidisciplinary Review J Clin Oncol, 2019.PMID 30395488
2. [2]Wu J, Ranjan S. Neoplastic Myelopathies Continuum (Minneap Minn), 2018.PMID 29613896
3. [3]Patchell RA, Tibbs PA, Regine WF, et al. Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial Lancet, 2005.PMID 16112300
4. [4]Bracken MB, Shepard MJ, Holford TR, et al. Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury. Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study JAMA, 1997.PMID 9168289
5. [5]Loblaw DA, Perry J, Chambers A, Laperriere NJ. Systematic review of the diagnosis and management of malignant extradural spinal cord compression: the Cancer Care Ontario Practice Guidelines Initiative's Neuro-Oncology Disease Site Group J Clin Oncol, 2005.PMID 15774794
6. [6]Byrne TN. Metastatic epidural spinal cord compression: update on management Semin Oncol, 2006.PMID 16769419
7. [7]Tuchman A, Pham M, Hsieh PC. The indications and timing for operative management of spinal epidural abscess: literature review and treatment algorithm Neurosurg Focus, 2014.PMID 25081968
8. [8]Lavy C, Marks P, Dangas K, et al. Cauda equina syndrome-a practical guide to definition and classification Int Orthop, 2022.PMID 34862914