[Predictive factors of resistance to treatment of neuropathic pain].

The aim of this retrospective study was to examine factors related to symptomatic pain treatment in 992 hospitalized patients referred to the pain clinic. These patients accounted for 1440 different pains (1.5 pains/patient), of nociceptive (59%), or neuropathic (24%) origin, a combination of both (16%) and of unidentified (1%) origin. Patients resistant to therapy did not differ from nonresistant patients (62%) in terms of age, sex, or number of pains. Although recommended pharmacological treatments were pursued, the neuropathic origin of pain was a factor in resistance to treatment. Among the neuropathic pains resistant to treatment (42%) a central nervous origin is more frequently found. Resistance to pain was more frequently encountered after strokes, primitive tumor of the central nervous system or traumatic plexopathy, whereas peripheral lesions of the nervous system were more easily controlled by symptomatic treatment. This study shows that central neuropathic pain is more frequently associated with resistance to recommended pharmacological symptomatic treatments. This observation underlines the limits of conventional medical therapy.