Spinal Posture as a Trigger for Episodic Headache within a Biopsychosocial context? An explorative study

Abstract

Although cervicogenic headache (CeH) is one of the most commonly seen headaches in primary care, scientific evidence for effectiveness of therapeutic approaches in the management of this headache disorder is scarce and inconsistent. Low therapy success rates in CeH might be related to its definition. The latter is general and gives the impression that CeH is a homogenous headache-type, purely based on pathoanatomical biomechanical features of the cervical spine. Since the episodic CeH-population could be more heterogeneous than originally thought, multidimensional subgrouping is suggested to increase therapeutic success. Based on the results of our first study: ‘Is There Support for the Paradigm Spinal Posture as a Trigger for Episodic Headache? A Comprehensive Review’ we proposed a potential multidimensional subgroup within the episodic CeHpopulation. Such subgroup, referred to as ‘Spinal Posture Induced Episode Headache’ or ‘SPIEH’, is presumed to consist patients, where based on multidimensional profiling, interactions between psychosocial, lifestyle, pain processing, and sitting posture characteristics can be established. To date, no clinical studies addressed such profiling in episodic CeH. Hence, the current doctoral thesis was designed as a novel contribution to scientific research to test this experimental hypothesis. The main objective being: To explore a potential multidimensional subgroup within episodic CeH, i.e. SPIEH. Three work packages (WP) were designed to analyse different dimensions of SPIEH within a biopsychosocial spectrum: WP1 Psychosocial and lifestyle, WP2 Pain processing, and WP3 Spinal sitting posture characteristics. Comparisons were made between the patients with SPIEH (SPIEHg) (n = 18) [40.2 (±10.9) years] and a matched (age, sex, BMI, socio-economic status) control-group (Cg) (n = 18) [39.2 (±13.1) years] before, during and after a 30-minute-desk-task. WP1. Psychosocial analysis showed a higher stress level and lower headacherelated quality of life in SPIEHg compared to Cg. Higher stress rates were related to more reported symptoms of central sensitisation. Lifestyle was related to outcomes of each work package in both groups. At SPIEHg, being less physical active was related to less thoracic extension and disturbed pain processing [i.e. lower extra-cephalic pressure pain thresholds (PPTs)]. Longer screen-time was related to more habitual thoracic flexion and end-range cervical protraction. At Cg, higher levels of physical activity and shorter sedentary-time were related to Abstract VIII higher extra-cephalic PPTs. Shorter sedentary-time was related to less symptoms of central sensitization and more upright thoracic postures. WP2. SPIEHg showed features of central sensitization within their pain processing characteristics. More reported symptoms of central sensitisation and lower cephalic and extra-cephalic PPTs compared to Cg supported a disturbance in pain processing. WP3. Analysis of spinal sitting posture revealed differences in baseline spinal posture between SPIEHg and Cg. Patients with SPIEH showed at the upper-thoracic spine less active-assisted maximal upper-thoracic extension and less end-range flexion, and at the upperlumbar spine more end-range flexion during habitual sitting compared to Cg. Additionally, postural awareness was influenced by the laptop-desk-task; patients with SPIEH showed a more flexed perceived optimal posture of the upper-thoracic spine after the task compared to before it. Next, spinal postural variability depended on the participant’s multidimensional baseline profile (i.e. psychosocial, lifestyle, pain processing characteristics, and baseline end-range spinal postures) at baseline and during the 30-minute-desktask. It can be concluded that variables of the three WPs interact. Such interactions between multidimensional characteristics and spinal postural variability seem to add new insights to the current research on episodic CeH. Psychosocial, lifestyle, pain processing, spinal postural characteristics and their interactions need to be explored to better comprehend spinal postural variability. Based on our results we propose within CeH a new subgroup, SPIEH. Characteristics of SPIEH can be summarized as: (1) disturbed pain processing, (2) flexed habitual spinal sitting postures and disturbed spinal postural awareness, (3) heterogeneous spinal sitting postural variability, and (4) interactions between lifestyle, psychosocial, pain processing and spinal sitting posture characteristics. These novel findings support the multidimensional nature of episodic CeH and the presence of different patient profiles within SPIEH. More research on other headache types is suggested to determine if SPIEH is a subgroup restricted to episodic CeH. For therapists new insights from this doctoral work, although to be cautiously interpreted, can be summarized as four key-messages for clinical practice. When Abstract IX examining patients with episodic CeH it is essential to: (1) consider the entire spinal column and spinal postural variability, (2) gather knowledge about psychosocial and lifestyle characteristics, (3) assess spinal posture both at baseline as well as during the provocative task, and (4) consider expressing habitual posture referred to its end-range. Based on this study, a multidimensional method is presented to approach the complex pain problem of episodic CeH. Yet, such method could also be translated to other pain problems. Patient profiling based on determinants could eventually contribute to more targeted or individual-specific therapy. Further, a new outcome measure (i.e. spinal postural variability) is proposed to analyse spinal posture in episodic CeH. However, longitudinal outcome research is needed to further test these findings on its full clinical validity. Identifying determinants of SPIEH is important for prevention, but also within the context of reversibility of SPIEH. In a stepwise process, case-control (n = 1) studies could be the next step, followed by randomised controlled studies before the discovery of this knowledge can be integrated into evidence-based clinical practice