Spinal Cord Compression

Spinal cord compression, though relatively rare, demands immediate attention to prevent permanent consequences. It complicates 4-7% of childhood malignancies from diagnosis to the end of treatment. Most cases of spinal cord compression occur in the terminal stages of relapsed or progressive cancer, but 25% present in children who have not yet been diagnosed. Other causes include infections such as osteomyelitis and abscesses, vertebral collapse, and hematomas or infarction, which can arise in oncology patients during treatment.

Approximately half of all SCC cases are caused by neuroblastoma or Ewing’s tumours. Thereafter, rhabdomyosarcoma, other soft tissue sarcomas and osteosarcoma account for the majority of the remaining incidences, although almost any metastatic tumour can result in SCC.

Pathophysiology

• Direct extension of the tumor.
• Metastatic spread to the vertebrae with secondary cord compression.
• Spread to the epidural space via infiltration of the vertebral foramina.
• Subarachnoid spread down the spinal cord from primary CNS tumor (such as medulloblastoma).

Clinical presentation

In older children, back pain is often the initial symptom, preceding any neurological dysfunction. Weakness tends to be symmetrical, manifesting as an unsteady gait, paraplegia, or quadriplegia, and it may coincide with sensory dysfunction and a gradual loss of sphincter control. The signs correspond to the level of spinal cord compression (SCC), including a defined sensory level, muscle weakness, heightened muscle tone, clonus, and extensor plantar reflexes. Palpation often reveals tenderness, and a palpable bladder is considered a grave sign in this scenario.

It is crucial to carefully assess potential spinal cord compression in young, ambulatory children, as the symptoms can be understated. Distinguishing between the loss of motor milestones (regression) and developmental delay is particularly vital, as the former raises significant concerns for spinal pathology. In older children, while lower limb weakness may stem from Guillain-Barré Syndrome, the possibility of spinal cord compression should also be contemplated, and an MRI of the spine is recommended.

Evaluation

• A thorough history and neurologic examination should be included in the evaluation.
• Spinal radiographs are useful if the compression is due to vertebral metastases, but they will miss epidural disease in 50% of cases.
• MRI with and without gadolinium is necessary to detect the presence and extent of epidural involvement.
• Cerebrospinal fluid analysis is important in the evaluation of subarachnoid disease, but it is not helpful in localizing epidural disease.

Treatment

• Because the potential for permanent neurologic damage is high, it is crucial to initiate treatment immediately.
• Dexamethasone is initiated to decrease local edema, prior to diagnostic studies.
• In the presence of neurologic abnormalities, immediately start dexamethasone 1-2 mg/kg/day loading dose. Follow with 1.5 mg/kg/day divided every 6 h and obtain emergent MRI.
• With back pain and the absence of neurologic symptoms, start dexamethasone 0.25-1 mg/kg/dose every 6 h and perform MRI within 24 h.
• If an epidural mass is identified, treatment is aimed at rapid decompression. Chemotherapy, radiation therapy, or surgical decompression may be used.
• Specific chemotherapy can be instituted in addition to the use of dexamethasone in lymphoma, leukemia, and neuroblastoma.
• If tumor is known to be radiosensitive, give local radiation including the full volume of the tumor plus one vertebra above and below the lesion. Consult a radiation oncologist for daily dosing fractions and total dose.
• Surgical emergent laminotomy or laminectomy may be indicated for paralysis requiring rapid decompression, especially in lesions expected to be less radio responsive (e.g., sarcoma) or no symptomatic improvement with emergent steroids, chemotherapy, and/or radiation.

References

• Philip Lanzkowsky (2022). Lanzkowsky’s Manual of Pediatric Hematology and Oncology. 7^th edition. London, UK: Elsevier
• Paediatric Haematology & Oncology: Supportive Care Protocols. A collaborative publication from Great Ormond Street Hospital for Children NHS Foundation Trust, The Royal Marsden NHS Foundation Trust, University College London Hospitals NHS Foundation Trust.