Tactile, thermal and pain sensibility in burned patients with and without chronic pain and paresthesia problems

Abnormal return of cutaneous sensibility is common after burn injuries and many patients complain of painful and/or paresthetic sensations in their healed wounds. However, little is known about the exact nature and severity of these problems. The present study was designed to provide a quantitative evaluation of the cutaneous sensibility in burned patients. Tactile, thermal and pain thresholds were measured in 121 patients with healed burns paired-matched to 121 control healthy subjects more than 18 months after the burns. Testing was confined to both upper limbs and was performed in a healed burn area and its contralateral burned or unburned counterpart. The tested sites were also divided into symptomatic and asymptomatic ones, depending on the presence or not of pain or paresthesia at the site. The results showed significantly higher sensory thresholds in burned patients than control subjects. Severity of the deficits of the various sensory modalities was, however, a function of burn depth. Deep burn injuries which had required skin grafts to heal were more seriously affected than superficial burns which had healed spontaneously. Significant sensory losses were found not only in burn sites but also in the non-injured areas suggesting changes in the central nervous system. When symptomatic and asymptomatic sites were compared, significant deficits were observed in the tactile modality (touch-pressure). Other significant predictors of chronic sensory problems were burn depth and patients' age. Pathophysiological mechanisms of diminished sensibility in burned and unburned skin as long as several years after the injury are discussed along with those implicated in pain and paresthesia problems reported by the patients.