Subscribe to NON-INTERVENTIONAL RETROSPECTIVE EVALUATION OF TOLERABILITY AND EFFICACY OF TYPICAL ORAL LONG-ACTING WHO-STEP III OPIOID ANALGESICs UNDER REAL-WORLD CONDITIONS IN PATIENTS SUFFERING FROM (LOW) BACK PAIN AFTER FAILURE OF A PREVIOUS TREATMENT WITH EITHER NONOPIOID, MILD OR STRONG OPIOID ANALGESICS (123TOWHO3)