Loss of descending inhibition of segmental reflex control leads to urinary urgency and incontinence. Acutely, however, lesions may be associated with a flaccid bladder and urinary retention, be segmental reflexes become active. Long tract findings, however, are prominent. Bladder function may be spared since bilateral lesions are required to interfere with bladder function. Extrinsic compression Extrinsic spinal cord compression from neoplasms or other masses affects the spinal cord by direct compression and by interference with blood supply.
Segmental findings are variable, and again depend on the level and extent of the lesion.
Sometimes, these are minimal. The long tract findings are clinically more important, since they indicate that there is spinal cord, rather than just nerve root, involvement. The lateral columns and intermediolateral columns are particularly prone to damage, so urinary urgency and lower extremity long tract motor signs are often the earliest manifestation of spinal cord compression. Loss of pain and temperature sensation may begin in the sacral region, and slowly ascend as the compression gets more severe, because the spinothalamic tract is laminated with the fibers from the sacral regions being most lateral and thus most vulnerable to compression. If a lesion in the center of the spinal cord extends over many segmental levels, segmental findings are prominent.