Post Traumatic Cold Intolerance is the most common, and often the most prominent disabilityfrom hand trauma. The discomfort caused by cold is believed to be linked to a dysfunction o f thedigital vasoregulation, but its pathophysiology is poorly understood. Cold induced vasospasm, i.e.the pathologically increased reactivity o f the digital vessels to cold, is commonly found in handsthat have sustained trauma, especially with damage to vascular and neural structures. This thesis is based upon a series o f clinical and laboratory studies on cold induced vasospasm andcold intolerance in 35 patients treated for digital amputation. The replanted digit was used as astudy model, since it represents a body part which at the moment o f reconstruction is devoid o f allinnervation. Replantations were performed according to two different principles o f vascularreconstruction; using long or short vessel grafts. Finger Systolic Pressure (FSP) was used as aparameter o f digital vasoregulation at different temperatures, and cold intolerance was assessedusing a logarithmic rating scale (Borg). Non-injured fingers and amputation stumps were used ascontrols. Clinical and laboratory investigations were performed at different intervals from oneweek to three years after the reconstruction. During the first two weeks following replantation, whole body cold exposure, or cooling o f thereplanted part to 10°C, did not cause serious spasm in the replanted vessels. Follow upinvestigations demonstrated that a cold related vasospastic tendency is established inapproximately 60% o f the replanted parts within one year after trauma. The once establishedpathologic vasoregulation, is unlikely to normalize spontaneously. Whether a cold related arterialspasticity will develop in the replanted digit or not, is not related to the surgeon's choice o ftechnique for vascular reconstruction. Cold related arterial spasticity was more common inamputation stumps than in replanted digits, Our findings suggest that there is a pathologicalreaction to cold in the distal palm vessels but the nature o f this disturbance is not clear. All patients developed some degree o f Post Traumatic Cold Intolerance. Approximately 60% o fthe patients stated that some improvement took place, but none o f the patients was free o f coldintolerance 1-7 years after the injury. Patients with a pathological cold induced vasospasm is likelyto present with severe cold intolerance, which indicates that the vasospasm is involved as one o fthe causes o f Post Traumatic Cold Intolerance. / <p>S. 1-48: sammanfattning, s. 51-110: 5 uppsatser</p> / digitalisering@umu