Does anyone know what stenosis of the spinal canal is?

JackieA

My husband has stage iv bc with mets to all bones including spine. My question is what is

mild to moderate stenosis of the spinal canal is present with primarily related to a bony expansile lesion...

Opinion of mri

1. Mildly expansile skeletal lesion involving right posterior L$ vertebral boy and medial right L4 pedicle., with some invasion of the spinal canal and effacement of the dural sac anterolaterally to the right as noted. This result is mild to moderate setenosis of the spinal canal. There is also bilateral L3 and L4 neroforaminal stenosis?

This is just one of the opinions of the Lumbar. Do you know what effects it will bring? if so please explain. Thank you