Abordaje fisioterapéutico de las alteraciones vasculares y su relación con el procesamiento del dolor crónico y la funcionalidad del miembro superior en pacientes con fenómeno de Raynaud

Abstract

ABSTRACT Raynaud's phenomenon manifests as a set of symptoms produced by a vasospastic disorder usually affecting the small vessels near the surface of the skin in the hands and feet and occurs in response to various stimuli such as exposure to cold or emotional stress. It is characterised by an acute, transient and reversible decrease in blood flow, accompanied by a change in skin colour, different levels of pain and functional impotence. It is classified into two main types, primary and secondary Raynaud's. In Raynaud's phenomenon, the alteration at the vascular level should be related to the processes of chronic pain, as well as with lower rates of functionality. These aspects have not yet been studied in depth and there are little known about the possible relationship between levels of vascular damage and the degree of pain, central sensitization and catastrophizing, as well as disability in people suffering from Raynaud's phenomenon. Furthermore, the effects of treatments proposed to manage this process have so far proved inconclusive. In this sense, we consider that iontophoresis treatment may improve the symptoms and upper limb disability in these patients, with minimal side effects; however, we have found no previous studies analysing the efficacy of this type of treatment. The main objectives of this thesis were: 1) To evaluate the relationship between vascular abnormalities and levels of pain, the processes related to chronic pain development (Central Sensitization and Catastrophizing), hand functionality and upper limb disability in people with Raynaud's phenomenon. 2) To evaluate the effectiveness of iontophoresis electrotherapy with tap-water on the severity of vascular symptoms, pain-triggering processes and symptoms and perceived upper limb disability in people with Raynaud's phenomenon. In this thesis, two observational studies and a randomised clinical trial were carried out to achieve the objectives outlined above. The first two studies included 37 people with Raynaud's phenomenon and 20 healthy controls and the third included 34 patients with Raynaud's phenomenon. Firstly, vascular condition were assessed by analysing the thermographic pattern of the hands, pain intensity, level of mechanosensitivity, electrical pain threshold, central sensitization and catastrophizing among people with primary and secondary Raynaud's phenomenon and healthy subjects. Secondly, we assessed the established vascular abnormalities through hand temperature, temperature recovery curve, oxygen saturation and blood flow; using range of motion and hand strength as indicators of hand functionality and the perceived disability in the carrying out activities of daily living at home, work and practising sports or artistic activities in people with Raynaud's phenomenon and healthy subjects. Lastly, 34 participants with Raynaud's phenomenon were randomly assigned either to an experimental group receiving iontophoresis electrotherapy (n=17) or to a control group (n=17) that continued with its usual treatment without receiving electrotherapy. The procedure was performed for 7 weeks, three times a week and with each session lasting 20 minutes. The main measurement tools used were hand temperature, temperature recovery curve, oxygen saturation, blood flow, pain level, central sensitization, catastrophizing and perceived upper limb disability. Each of these variables were assessed at three different times: a baseline assessment before beginning the intervention, a post-treatment assessment and a follow-up assessment, performed two months after the intervention. Our results suggest that people with Raynaud's phenomenon have a lower basal hand temperature (P≤0.012); higher levels of pain (P≤0.001) and lower pain thresholds on pressure (P≤0.05) than healthy people. People with secondary Raynaud's phenomenon showed raised levels of central sensitization compared to those with primary Raynaud and healthy people (P=0.001). Catastrophizing was significantly higher in both groups of subjects with Raynaud's phenomenon (P≤0.001) compared to healthy controls. Disability in the upper extremities was significantly higher (P≤0.01) in both forms of RP compared to the controls with lower blood flow in the radial artery (P=0.006). The multivariate regression analysis confirmed that index finger extension (β=-0.348, P=0.010) and lateral pinch strength (β=-0.427, P=0.001) were significantly associated with the disability presented by people with Raynaud's phenomenon, explaining 55% of the total variance. Ultimately, iontophoresis treatment with tap-water demonstrated a significant improvement in terms of the number of attacks (P<0.001), pain (P=0.002), blood flow (P=0.001), oxygen saturation (P≤0.002), temperature curve recovery (P≤0.014), central sensitization (P<0.003) and upper limb disability (P<0.001) in patients who received this treatment versus the control group. The main conclusions were, firstly, that people with Raynaud's phenomenon had lower hand temperature and a pattern of bilateral pressure pain hypersensitivity. The severity of vascular abnormalities does not, however, appear to be related to the experience of central pain in this population and central sensitization only appearing to occur in secondary Raynaud's. Furthermore, people with Raynaud's phenomenon showed higher levels of catastrophizing than healthy people. These additional pain mechanisms may contribute to maintaining the pain process over time, as well as a worse outcome and a worse response to treatments in these patients. Secondly, participants with Raynaud's phenomenon showed greater perceived hand and upper limb disability in carrying out daily activities at home, at work and when practising sports, especially those with secondary RP. This disability, however, appears to be more related to the loss of range of motion in the hand joints and the decrease in strength than with vascular abnormalities or involvement. Thirdly, iontophoresis treatment with tap-water appears to be effective in improving the symptoms of this disease in its two forms of presentation. Therefore, assessing aspects such as those presented in this thesis relating to pain, chronic pain processing, functionality and disability should be considered in order to take a holistic approach to these patients. Consideration should also be given to including iontophoresis with tap-water in the intervention protocols for people with Raynaud's phenomeno