G Finco

Functional plasticity in the human primary somatosensory cortex following acute lesion of the anterior lateral spinal cord: neurophysiological evidence of short-term cross-modal plasticity.

&NA; The primary somatosensory cortex (S1) in adult animals and humans is capable of rapid modification after deafferentation. These plastic changes may account for a loss of tonic control by nociceptive inputs over inhibitory mechanisms within structures of the dorsal column‐medial lemniscal system. Most studies, however, have been performed under conditions where deafferentation of C and A&dgr; fibres coexists with large‐diameter fibres deafferentation. In this study the effect of the acute lesion of one ascending anterior lateral column on neuronal activity within the dorsal column‐medial lemniscal system was assessed by recording somatosensory evoked potentials (SEPs) in seven patients who underwent unilateral percutaneous cervical cordotomy (PCC) as treatment for drug‐resistant malignant pain. Spinal, brainstem and cortical SEPs were recorded 2 h before and 3 h after PCC by stimulating the posterior tibial nerve at both ankles. Amplitudes of cortical potentials obtained by stimulation of the leg contralateral to PCC were significantly increased after PCC. No significant changes in spinal or brainstem potentials were observed. PCC did not affect SEP components obtained by stimulation of the leg ipsilateral to PCC. Our results suggest that nociceptive deafferentation may induce a rapid modulation of cortical neuronal activity along the lemniscal pathway, thus providing the first evidence in humans of short‐term cortical plasticity across the spinothalamic and lemniscal systems.

Radiofrequency treatment of cancer pain.

An accurate analysis of the pain experienced by the patient is now the sine qua non for an accurate pain therapy. The type of pain (somatic, visceral, neurogenic), the temporal pattern (continuous or incident pain), the intensity and the site of pain, and the site and the evolution of the painful lesions constitute the basis of the therapeutic analgesic approach in cancer patients. Moreover, aspects which should always be borne in mind are the patient survival curves, the time from onset of pain, the point at which pain fails to respond to nonsteroidal anti-inflammatory drugs and requires opioid treatment, and the likely duration of the efficacy of the treatment. In the light of these very basic considerations, it is clear that the mainstay of cancer pain treatment is the pharmacological therapy. 1 Cancer related pain can be adequately treated in most patients using relatively simple methods such as the regular administration of non opioid or opioid analgesics. 2 The remaining patients, especially those with neurogenic or incident-type pain, are less responsive to these methods and may require more aggressive approaches, such as neuroinvasive or neuroablative procedures. 3

Guidelines on chronic pain management

Chronic pain represents a topic of medicine to which an univocal and especially efficacious solution has not yet been found. The lack of unequivocally efficacious medical devices pressures physicians into searching for personal solutions which often have no clinical rationale and may expose the patients to useless, and sometimes increased, suffering. Moreover, many physicians attempt a pain therapy without adequate technical and scientific preparation. It is, therefore, of major importance to establish some guidelines for the treatment of chronic pain which are based on the demonstration of the efficacy of each device or, if this is not possible, on a physiopathologic rationale which suggests their use. The aim of this paper is to identify, based on the international literature and on our own clinical and scientific experience, criteria on which an adequate treatment of different types and clinical presentations of pain can be developed.