Posterior disc protrusion at lumbar4?

Usually time heals: 90% of disc herniations including extrusions heal over time without surgery. One study looked at mris in people with symptomatic disc herniations & then repeated a MRI 6 months later & the disc herniation was no longer present or significantly reduced in size. For most, it is not only the actual compression of the nerve by the disc, but the inflammation caused by the herniation that resolves.

L4 Radiculopathy: Disk herniations at l4-5, could cause pressure to either the L4 or L5 nerves or both. L4 would cause pain or numbness along the front and inside if the shin stopping at the ankle. L5 would cause the outside of the calf and top of the foot to be affected. Weakness bringing the toes and ankle up may be present with both, but L4 could cause thigh/quads weakness. Mri would answer definitively.

It is a Herniation: By definition a disc protrusion is a herniated disk.