Desiccation, as the word suggests, refers to the drying up of the inner stuffing of the disc-shaped shock-absorber placed by nature between any two vertebrae. As we age, the contents of the disc suffer degenerative changes with consequent loss of elasticity. One consequence is their tendency to sag and bulge in all directions. When the desiccated disc bulges backward, it may press upon one or more nerves travelling down the spinal canal and result in pain, paresthesiae and weakness of muscles of the lower limbs.
You need to check with your doctor whether the abnormal discs are compressing nerves, and if so, whether there is any abnormality of function of these nerves. If there is compression of nerves, the term slipped disc could be applied here. Further treatment would depend on the degree of compromise of nerve function by the pressure.