Quantitative sensory tests in patients with neuralgia 11 to 25 years after injury

In a previous study quantitative sensory tests were used to characterize the symptoms in patients with post-traumatic neuralgia in the hand. Two types of pain syndromes were identified, sympathetically maintained pain (SMP), and sympathetically independent pain (SIP). These two syndromes had different sensory profiles with regard to temperature discrimination and cold and heat pain thresholds. The aim of the present study was to investigate the development of symptoms 10 years later. Eighteen previously investigated patients were contacted and all answered questions concerning their symptoms. Of these, two SIP and eight SMP patients agreed to undergo quantitative sensory testing. The outcome of these tests and the patients' own reports indicated that patients with SMP, who were not repeatedly treated with sympathetic blocks, did not show any remarkable spontaneous improvement of symptoms over a decade. The SMP patients still exhibited their characteristic sensory profile with moderate impairment of temperature discrimination and allodynia to cold, heat and vibratory stimuli. However, some changes with time were observed with respect to warm-cold difference limen and vibration allodynia. Comparison with data obtained from an age-matched group of healthy individuals indicated that these changes were due to age-related factors.