Aim This study aims to assess the effectiveness of an early intervention comprising individually tailored physiotherapy, including dialogue, education, and graded activity, following lumbar spinal fusion surgery. The effectiveness will be evaluated on patient-specific goals, physical activity, pain intensity, pain interference, fear of movement, and pain self-efficacy for patients after a lumbar spinal fusion.

In 2023, above 1400 patients underwent lumbar spinal fusion (LSF) in Denmark to treat CLBP. LSF aims to relieve pain by eliminating movement between joints by fusing one or more adjacent vertebrae. The use of LSF has been increasing because of the ageing population and because of improvements in surgical techniques and technologies.

Unfortunately, despite LSF surgery, many patients are not improving their physical activity level post-surgery, and inactivity is associated with an increased risk of disease mortality.

Therefore, healthcare professionals must address physical activity in post-surgical rehabilitation to help patients achieve healthy behaviour after surgery.

To perform physical activity, both physiological, psychological, and social factors have an influence. Further, qualitative interviews with patients undergoing LSF reveal significant concerns about engaging in physical activity after surgery. It thereby seems important that a rehabilitation approach includes a bio-psycho-social approach to incorporate the complexity of physical activity.

Rehabilitation involving physical exercises combined with a cognitive behavioural approach (CBA) has shown beneficial effects on short- and long-term functional outcomes in patients undergoing LSF. The purpose of CBA is to provide patients with techniques that can lead to a sense of control over their lives, despite pain. The approaches have no sharply defined treatment modalities but include a range of techniques that modify the behavioural, cognitive, affective, and sensory aspects of pain. Tegner et al. supported the evidence of a CBA in an RCT by showing that CBA was safe to start with just after LSF and significantly affected fear of movement and sedentary behaviour compared to usual care.

Despite the increasing consensus regarding an early CBA for patients after LSF, several problems remain unsolved. First, in many studies, the beneficial effect of an early approach consisting of CBA post-surgery is not above the minimal clinically important change.

Secondly, a huge concern is that rehabilitation, including CBA, is complex and time-consuming and thereby difficult to implement in a clinical setting where time and resources are sparse. Thirdly, it is still uncertain what drives the beneficial effects of CBA, what constitutes optimal intervention timing, and which components moderate and mediate change in physical activity behaviour.

To investigate these problems, several initiatives are needed, among others, the use of alternative research methods which include the individual patients much closer. Furthermore, a close collaboration between health sectors is important to integrate each responsible partner in the rehabilitation process, to incorporate the essential expertise and experience, and finally to be able to design an intervention that is realistic and manageable to implement in clinical practice.

Therefore, in this project, the investigators will implement an early CBA in close collaboration between partners from the hospital and a rehabilitation centre. Further, the investigators would like to test the effect of the intervention closely on patients after surgery based on function, physical activity and pain response by a single-case experimental study design (SCED) in the setting where the rehabilitation in clinical practice will be performed.

Aim and hypothesis This study aims to test the effectiveness of an early intervention consisting of a CBA on a patient-specific goal, physical activity, pain intensity, pain interference, fear of movement, and pain self-efficacy for patients after an LSF. An intervention planned between sectors and delivered in a community care centre.

The investigators will in total include 12 patients undergoing an LSF from the Centre for Rheumatology and Spine Diseases at Rigshospitalet, Denmark.

Before inclusion, a pilot of three participants will be performed.

Inclusion Criteria for all included:

• ≥ 18 years of age
• Low back pain (LBP) > 3 months
• Read and understand the Danish language
• The participants should be a part of Frederiksberg Municipality and Copenhagen Municipality (in Denmark)

Exclusion Criteria:

• Post-traumatic vertebral compression/deformity
• Patients with the following conditions (infection, neoplasm, metastasis, metabolic bone disease, fractures or other known autoimmune arthropathies)
• Patients with patient-related circumstances (physical or mental status) that impede their ability to give informed consent and adhere to the study program (e.g., dementia, developmental disorders, or substance-induced cognitive impairment)
• Other special conditions, where the patient is judged by the surgeon as inappropriate to participate

On reasonable request

Starting 6 months after publication

De-identified individual participant data will be shared with qualified researchers who have a scientifically relevant research question. Data sharing will be subject to approval of a written research proposal describing the planned analyses. Access will require the signing of a data sharing agreement outlining the purpose of use, data protection, and confidentiality. Requests can be submitted by contacting the study investigators.

Full blinding is not feasible in this MBD. Allocation to baseline length will be concealed until the intervention is initiated. The randomisation schedule will be generated by co-investigator Jan Christensen.