The following SQL script will delete unused practice areas.

--Delete any practice areas that are not used
UPDATE
    __M_Matters_PracticeAreas
SET
    Final_Status = 'Deleted'
WHERE 1=1
    AND Id NOT IN(
        SELECT
            Final_PracticeArea_Id
        FROM
            __M_Matters
        WHERE
            Final_Status != 'Deleted'
    )