What is the ICD-9 code for chronic back pain?

The ICD-9 code for chronic back pain is 338.4 as related to psychosocial functions, according to Health Research Funding. Chronic back pain is defined as back pain that persists for over three months. Causes for the pain may include injury, disease, structure of the backbone or general back stressors.

Chronic back pain may also be classified under the ICD-9 code 338.29, which covers chronic pains not listed elsewhere in the ICD-9, according to ICD9Data. It may also be listed under the code 724.5 in the ICD-9 code, which covers backaches generally, including those lasting both shorter or longer than three months.