Background: Low back pain (LBP) and comorbid post-traumatic stress symptoms (PTSS) are common after traumatic injuries, and a high level of PTSS is associated with more severe pain and pain-related disability. Few randomised controlled trials (RCT) exist targeting comorbid PTSS and chronic pain, and only one has assessed the effect of Somatic Experiencing®. Objective: The aim of this study was to assess the effect of Somatic Experiencing® (up to 12 sessions) + physiotherapeutic intervention (4-8 sessions) (SE+PT) compared with the physiotherapeutic intervention alone (4-8 sessions) (PT) for pain-related disability in LBP with comorbid PTSS. Methods: The study was a two-group RCT in which participants (n = 114) were recruited consecutively from a large Danish Spine Centre. Patients were randomly allocated to either SE+PT or PT alone. Outcomes were collected at baseline before randomisation, 6 and 12month post-randomisation. The primary outcome was pain-related disability as measured with the modified version of the Roland Morris Disability Questionnaire at 6-month postrandomisation. Secondary outcomes were PTSS, pain intensity, pain-catastrophising, kinesiophobia, anxiety and depression. Results: No significant group differences were found on any of the outcomes at any timepoints. Both groups achieved a significant reduction in pain-related disability (20-27%) as measured by the Roland Morris Disability Questionnaire at 6 and 12-month follow up. Also, both groups achieved a small reduction in PTSS. Conclusions: Although significant effects were achieved for both groups, the additional SE intervention did not result in any additional benefits in any of the outcomes. Experiencia Somática® para pacientes con lumbalgia y síntomas comórbidos de estrés postraumático-un ensayo clínico aleatorizado Antecedentes: La lumbalgia y los síntomas comórbidos de estrés postraumático (SCET) son comunes luego de lesiones traumáticas, y un alto nivel de los SCET está asociado con dolor más severo y con discapacidad asociada al dolor. Existen escasos ensayos clínicos aleatorizados enfocados en los SCET y en dolor crónico, y solo uno ha evaluado el efecto de la Experiencia Somática®. Objetivo: El objetivo de este estudio fue el de evaluar el efecto de la Experiencia Somática® (hasta un máximo de 12 sesiones) adicionada a la intervención fisioterapéutica (entre 4 a 8 sesiones) (ES+IF), comparada con la intervención fisioterapéutica sola (entre 4 a 8 sesiones) (IF), sobre la discapacidad asociada al dolor en lumbalgia con SCET. Métodos: El estudio consistió en un ensayo clínico aleatorizado de dos grupos para el que se reclutó a participantes (n=144) consecutivamente de un gran Centro Danés de Columna Vertebral. Los pacientes fueron distribuidos aleatoriamente al grupo de ES+IF o al grupo de solo IF. Los puntos de corte se realizaron de base antes de la aleatorización, y a los 6 y 12 meses luego de la aleatorización. El resultado principal era la discapacidad asociada a dolor, medida mediante la versión modificada del Cuestionario de Dis...