Is there tratment for spasticity due to cervical myelopathy ?

Spasticity: There's no 100% cure. Most effective treatment I am aware of is a medication called Baclofen (lioresal), that is dosed as 10-20 mg 3 times a day. For more severe spasms there are surgical releases or nerve eradication procedures.

Many: Physical therapy, oral medicine, Botox and phenol treatment, intrathecal Baclofen pump in graded fashion.

Yes: Taking pressure off the spinal cord can reduce spasticity in some cases. Medication can help as well. For some, an pump can be implanted to put drug directly into the spinal fluid to reduce spasticity. See a physician who specializes in care of myelopathy (spine surgeons, many neurosurgeons, spinal cord injury specialists, rehabilitation specialists).