A factor analysis was performed on eleven variables derived from scores on the McGill Pain Questionnaire, Oswestry Activity Rating Scale, graphic rating scales designed to assess the average pain intensity, frequency of leg pain, back pain, numbness and tingling in legs, and weakness in legs, as well as bothersomeness of back pain, leg pain, numbness and tingling in legs and weakness of legs. A composite Pain Index was created on the basis of three factors: leg pain, back pain, and overall pain complaints. Extraclassificatory variables, such as negative affect including depression and anxiety, cognitions regarding health status and expectation of recovery, bodily awareness/somatization and demographic variables such as smoking or non-smoking, compensation status, litigation status, use of narcotic and non-narcotic medication, use of alcohol, and time off of work were analyzed in combination and independently in relationship to the Pain Index.

Background: Chronic pain, defined as non-malignant pain emanating from the musculoskeletal system, may limit everyday activities, social functioning and the quality of social and working life for individuals, creating disability as well as incurring high economic and public costs for society. Controlled studies show that cognitive-behavioural interdisciplinary rehabilitation has a positive effect on functioning in patients who have been disabled by chronic non-malignant pain conditions. Positive outcomes described include lower pain intensity, less preoccupation with pain, greater independence and lower consumption of healthcare. On the other hand, the return to work rate varies. To facilitate comparisons on the national level and to enable audit spirals for single programmes as part of the ongoing quality assurance in healthcare the Swedish Quality Registry for Pain Rehabilitation (SQRP) has aggregated data since 1998 on all patients referred to the majority of Swedish rehabilitation units. The aim of this dissertation was to improve the knowledge base of pain rehabilitation in Sweden using the validated self-reported instruments of pain and its consequences included in the SQRP. Methods: The SQRP data were collected before, at the end and 1 year after the intervention for all individuals included, and concerns self-reported demographic variables, pain intensity, activities, thought patterns, impact of pain on daily life and life satisfaction. Individual sick leave data were collected from the Swedish Social Insurance after 1 year. Data collected from 19833 patients (6002 men and 13831 women) of which 7289 participate in work ability improving programmes, were used. Results: The results of four studies included in this thesis showed that the SQRP provided a basis for scientific works since it use the validated self-report instruments of pain and its consequences and contain a large amount of patient’s data. However, a lack of follow-up data from some units influenced the opportunity of to analyse long-term outcomes. Nevertheless, the SQRP was a useful tool to audit and evaluate as well as to propose optimising of pain rehabilitation. It seemed that contextual factors such as patients’ own beliefs and expectations, education, gender, actual sick leave and employment situation had more importance for the effect of rehabilitation programme than pain characteristics, depression or activity limitation. The Multidimensional Pain Inventory (MPI) scale scores and MPI coping profiles might be used for assessing the outcomes of treatment interventions. A reduction of MPI scale scores for Pain severity and Interference decreased the risk of being on full-time sick leave. On the other hand, the MPI coping profiles Dysfunctional, among both men and women, and Interpersonally distressed, among women, were associated with higher odds of being on full-time sick leave. Conclusions: Attending cognitive-behavioural interdisciplinary pain rehabilitation programmes in Sweden resulted in improvements of the MPI scales after completing a pain rehabilitation programme and this improvement was sustained after 1 year. Moreover, these programmes decreased the levels of full-time sick leave 1 year after completed programme. The findings suggest also the need to tailor rehabilitative strategies differently for men and women as well as for different pain coping profiles.

The overall aim of this thesis was to study the daily process of coping, potential prognostic factors for recovery and evaluating an individually tailored behavioural medicine intervention in the acute stage of Whiplash Associated Disorders (WAD). The studies comprised three samples of patients with acute Whiplash Associated Disorders (WAD). All patients were included within the first month after the whiplash occurrence and were recruited from hospital emergency wards in six Swedish communities. Study I and II included 51 participants generating 260 daily coping diaries (WAD-DCA) during seven days in the acute stage of WAD. In Study I daily stressors and primary appraisal were analysed and in Study II patterns between stressors, appraisals, coping strategy profiles, daily activity level and well-being were described. The results showed a large variety of situations that the individuals perceive as stressful, not only pain itself. High self-efficacy was associated with high degree of physical/mental well-being. Threatening stressors and catastrophic thoughts were associated with low degree of physical and mental well-being. In Study III potential prognostic factors for good as well as poor recovery were studied more closely in a mildly affected sample (MIAS) (n=98) from within the first month after the accident up to one year later. Pain-related disability at baseline emerged as the only indicator of prognosis after 12 months in MIAS. Study IV (n=55) was a randomised control study, were current clinical recommendations of standard self-care instructions (SC) for the management of acute WAD was compared to an individually tailored behavioural medicine intervention delivered via Internet or face-to-face. The results showed that SC was not as effective as the behavioural medicine intervention. By early identification of situation-specific factors and potential behavioural (physical, cognitive and affective) determinants of activity performance, it seems possible to tailor a self-management intervention that decreases pain-related disability, fear of movement and catastrophising and increases self-efficacy. The use of innovative methods such as the Internet of distributing treatment interventions showed to be a good alternative to more traditional forms. The results of this thesis uncover new insights in understanding the individual’s specific perspective as applied in a behavioural medicine approach in acute WAD.

SyfteUndersöka påverkan av kronisk orofacial smärta och psykologiska faktorer på sömnkvalitet vid käkmuskelmyalgi.Material och metoderDenna retrospektiva studie omfattade 37 patienter (6 män, 31 kvinnor, medelålder: 49 år) med käkmuskelmyalgi. Sömnkvalitet (Pittsburgh Sleep Quality Index), smärtintensitet och smärtrelaterad funktionsnedsättning (Graded Chronic Pain Scale), depression (Patient Health Questionnaire-9), ångest (General Anxiety Disorder-7), stress (Perceived Stress Scale-10) och katastrofiering (Patient Catastrophizing Scale) undersöktes med varierade formulär. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) användes för att identifiera patienter med myalgi i käkmuskulatur.Resultat75% av patienterna rapporterade dålig sömnkvalitet, 73% rapporterade minst mild depressionsgrad, 54% rapporterade minst mild ångest, 59% rapporterade måttlig stressnivå och 38% rapporterade kliniskt relevant katastrofiering. Försämrad sömnkvalitet var relaterad till depression (rs = 0.45, n = 37, p = 0.008) ångest (rs = 0.46, n = 37, p = 0.007), stress (rs = 0.43, n = 37, p = 0.014) och katastrofiering (rs = 0.37, n = 37, p = 0.034). Multivariat logistisk regression visade att smärtintensitet, smartrelaterad funktionsnedsättning, depression, ångest, stress, katastrofiering och antal käkmuskler med refererad palpationssmärta förklarade dålig sömnkvalitet signifikant (p = 0.031).KonklusionSömnkvaliteten hos patienter med käkmuskelmyalgi påverkas i hög grad av kronisk smärtintensitet, smärtrelaterad funktionsnedsättning, antal käkmuskler med refererad palpationssmärta och depression samt ångest, stress och katastrofiering. / AimInvestigate the influence of chronic orofacial pain and psychological factors on sleep quality in patients with myalgia of the masticatory muscles.Material and methodsThis retrospective study included 37 patients (6 men, 31 women, mean age: 49 years) with masticatory muscle myalgia. Sleep quality (Pittsburgh Sleep Quality Index), pain intensity and pain-related disability (Graded Chronic Pain Scale), depression (Patient Health Questionnaire-9), anxiety (General Anxiety Disorder-7), stress (Perceived Stress Scale-10) and catastrophizing (Patient Catastrophizing Scale) were assessed by questionnaires. The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were used to identify patients with myalgia.Results75% of the patients reported poor sleep quality, 73% reported at least mild depression degree, 54% reported at least mild degree of anxiety, 59% reported at least a moderate stress level and 38% reported a clinically relevant degree of catastrophizing. Impaired sleep quality was related to degree of depression (rs = 0.45, n = 37, p = 0.008), anxiety (rs = 0.46, n = 37, p = 0.007), stress (rs = 0.43, n = 37, p = 0.014) and catastrophizing (rs = 0.37, n = 37, p = 0.034). Multivariate logistic regression showed that characteristic pain intensity, degree of pain-related disability, depression, anxiety, stress, catastrophizing and number of masticatory muscle sites with referred pain significantly explained poor sleep quality (p = 0.031).ConclusionSleep quality in patients with masticatory myalgia is influenced by chronic pain intensity and related disability, number of masticatory muscle sites with referred pain as well as depression, anxiety, stress and catastrophizing.

Objetivos: A dor neuropática crônica origina-se em consequência direta de uma lesão ou doença que afete o sistema somato-sensitivo. Pacientes que são refratários ao tratamento conservador são considerados candidatos a procedimentos invasivos, principalmente de ordem neuro-modulatória. A estimulação do gânglio da raiz dorsal é uma técnica recente de neuromodulação utilizada para o tratamento das dores neuropáticas crônicas de diferentes etiologias. Apesar do sucesso clínico da estimulação do gânglio da raiz dorsal no tratamento de dor neuropática já ter sido relatado em diversos trabalhos da literatura, os mecanismos neurofisiológicos responsáveis pelo alivio da dor ainda permanecem pouco esclarecidos. O presente trabalho avalia o efeito da estimulação do gânglio da raiz dorsal no processamento cortical da dor através do método de potenciais evocados a laser (PELs). Métodos: Avaliamos prospectivamente por 3 anos 34 doentes com dor inguinal (grupo 1), 62 doentes com dores neuropáticas diversas (grupo 2) que foram submetidos a estimulação do gânglio da raiz dorsal. Nestes 2 grupos foram analisadas variáveis relacionadas a intensidade da dor, incapacidade relacionada a dor, níveis de depressão e pensamentos catastróficos relacionados a dor. Adicionalmente, um subgrupo de 12 pacientes submetidos à cirurgia de estimulação do gânglio da raiz dorsal para tratamento de dor neuropática crônica unilateral da região inguinal, joelho ou perna por lesão direta de nervo periférico após procedimento cirúrgico, síndrome do insucesso da cirurgia espinhal ou síndrome dolorosa regional complexa tipo II foi avaliado de forma prospectiva (grupo 3). O lado normal foi utilizado como controle. PELs foram evocados por meio de estimulação a laser de CO2 na área desaferentada e normal. Latências e amplitudes dos componentes N2 e P2 e amplitudes do complexo N2-P2 foram correlacionados à intensidade da dor antes da terapia e após 1 e 6 meses de tratamento com estimulação do gânglio da raiz dorsal. Testes sensitivos quantitativos, escalas de intensidade da dor, incapacidade relacionada a dor, qualidade de vida, e depressão foram avaliadas. Resultados: Houve aumento significante das amplitudes do complexo N2-P2, igualando-se ao lado normal, e em paralelo diminuição significativa da intensidade de dor e na incapacidade relacionada à dor após 1 e 6 meses de tratamento em comparação com o estado pré-tratamento. Houve melhora significativa em 2 dos 8 itens de qualidade de vida avaliados. Não houve alteração significativa nos testes sensitivos quantitativos e na escala de depressão. Conclusão: A estimulação do gânglio da raiz dorsal restabeleceu as amplitudes dos PELs oriundos do giro do cíngulo anterior, ínsula e áreas temporais mediais, restaurando o processamento cortical fisiológico de dor em pacientes com dor neuropática crônica / Objectives: Chronic neuropathic pain originates as a direct consequence of an injury or disease that affects the somatosensory system. Patients who are refractory to conservative treatment are considered candidates for invasive procedures, mainly of neuro-modulatory order. Dorsal root ganglion stimulation is a recent neuromodulation technique used for the treatment of chronic neuropathic pain of different etiologies. Although the clinical success of dorsal root ganglion stimulation in the treatment of neuropathic pain has already been reported in several studies in the literature, the neurophysiological mechanisms responsible for pain relief remain unclear. The present study evaluates the effect of dorsal root ganglion stimulation on cortical pain processing through the use of laser evoked potentials (LEP). Methods: We evaluated prospectively during 3 years 34 patients with groin pain (group 1), 62 patients with various forms of neuropathic pain (group 2) who underwent dorsal root ganglion stimulation. In these 2 groups, variables related to pain intensity, pain-related disability, depression levels and painrelated catastrophic thoughts were analyzed. In addition, we prospectively analyzed a subgroup of 12 patients treated with dorsal root ganglion stimulation for treatment of chronic unilateral neuropathic pain of the groin region, knee or leg caused by direct injury of the peripheral nerve after surgical procedure, failed back surgery syndrome or complex regional pain syndrome type II (group 3). The healthy side was used as control. LEPs were evoked by means of CO2 laser stimulation in the deafferented and normal areas. Latencies and amplitudes of the N2 and P2 components and amplitudes of the N2-P2 complex were correlated to the pain intensity before therapy and after 1 and 6 months of treatment with dorsal root ganglion stimulation. Quantitative sensory testing, pain intensity scales, pain-related disability, quality of life, and depression were assessed. Results: There was a significant increase in N2-P2 complex amplitudes, matching the normal side, and in parallel a significant decrease in pain intensity and pain-related disability after 1 and 6 months of treatment compared to the pre-treatment state. There was a significant improvement in 2 out of 8 quality of life domains evaluated. There was no significant change in quantitative sensory testing and depression levels. Conclusion: Stimulation of the dorsal root ganglion reestablished the amplitudes of the LEPs originated from the anterior cingulate gyrus, insula, and medial temporal areas, restoring physiological cortical pain processing in patients with chronic neuropathic pain