Which of the following is used to treat pain

There are various modalities of treatment which are tried for chronic pain:- i) Pharmacotherapy:- The various drugs (mentioned above) are used for chronic pain syndrome. The various routes can be used:- oral, intravenous, epidural, or Transcutaneous. ii) Neuro-surgical:- Anterolateral cordotomy, dorsal root entry zone lesion, selective rhizotomy, commissural myelotomy, sympathectoning mesencephalic tractomy, cordectomy iii) Chemical neurolysis:- Glycerol, alcohol, phenol e.g. intrathecal hyperbaric phenol. iv) Other:- Acupuncture, transcutaneous electric nerve stimulation, neuromodulation procedures (intracranial stimulation:- deep brain/subcortical and motor cortex stimulation), cryoablation.