464 CHAPTER 10 Trauma to the urinary tract

Spinal cord and cauda equina compression

Spinal cord compression due to spinal metastases from urological cancers

This is a urological oncological emergency; failure to diagnose and treat promptly can lead to permanent paraplegia and autonomic dysfunction (failure of bladder and bowel emptying; inability to achieve an erection).

Due to epidural compression arising from vertebral body metastasis in the majority of cases, 95% of patients will complain of back pain and have a positive bone scan. Ten percent of cases do not exhibit these features because their disease is paravertebral.

Patients with back pain should be examined neurologically and evaluated radiologically. Pain usually precedes cord compression by about 4 months. Other clinical features include sensory changes and muscle weakness in the lower limbs and bladder and bowel dysfunction, and these can progress rapidly to become irreversible.

If cord compression is suspected, the investigation of choice is spinal MRI, which will reveal the deposits (multiple in 20% of cases).

Treatment

Initial treatment is with high-dose intravenous corticosteroids (e.g., dexamethasone 10 mg followed by 4 mg q6h for 2–3 weeks). If the patient has prostate cancer but has not had prior androgen deprivation therapy, ketoconazole should be started to lower circulating androgen levels.

Without delay, further treatment with direct spinal radiotherapy or, less frequently, neurosurgical decompression is carried out. Surgery should be considered preferable if there is a pathological fracture, unknown tissue diagnosis, or previous history of radiotherapy.

Cauda equina compression

The adult spinal cord tapers below L2 vertebral level into the conus medullaris. The cauda equina consists of nerve roots of spinal cord segments below L2, as they run in the subarachnoid space to their exit levels in the lower lumbar and sacral spines.

Pathophysiology

The cauda equina may be compressed by a central intervertebral disc prolapse, spinal stenosis, or a benign or malignant tumor within the lower lumbar or sacral vertebral canal.

Symptoms

The diagnosis should be considered in any female or young male presenting with difficulty voiding or in urinary retention. There may be back pain.

Signs

These include palpable bladder, loss of perianal (S2–4) and lateral foot sensation (S1–2), reduced anal tone, and priapism.

Treatment is intermittent self-catheterization.