Background An increasing number of patients with chronic low back pain (CLBP) undergo lumbar spinal fusion (LSF). Unfortunately, a substantial part of the patients still has persistent pain, functional disability and poor quality of life after surgery. Research in the field of rehabilitation after LSF call for high quality research to focus on active approaches which incorporate an early bio-psycho-social focus. A focus which include the patient's context, experiences and thoughts even more in the clinical decision making.

The primary objective of this trial is to examine the effect of an early active rehabilitation-intervention consisting of Graded Activity and Pain Education (GAPE) on sedentary behavior in a population of patients undergoing LSF. The secondary objectives are to examine the effect of GAPE on disability, pain, fear of move-ment, self-efficacy for exercise and health related quality of life.

Methods:

The study is a randomized controlled trial planned to include 144 patients after LSF caused by degeneration of the lumbar spine (including spondylolisthesis). The patients will be randomly assigned to receive either usual care or usual care plus GAPE. GAPE consists of 9 individual sessions, with an overall purpose to influence the patient beliefs and thoughts about movement and pain towards increased self-efficacy for exercise and decreased fear of movement. A physiotherapist will in close collaboration with the patient plan GAPE based on an in-depth pain-anamnesis, individually set functional goals and observations of the patients in their homes. The primary outcome will be "reduction in sedentary behavior" measured by an accelerometer. Sec-ondary outcome will include disability, pain, fear of movement, self-efficacy for exercise and quality of life. Data will be collected at baseline (pre-surgery), and at 3, 6- and 12-months post-surgery.

Introduction:

Over half a Billion people worldwide report low back pain (LBP), and it is the leading cause of disability at all levels of income and age groups. For the majority of people with LBP the condition has a natural course and the pain will diminish over time, but for a small percentage the conditions turns into a chronic state with significant levels of life disruption, healthcare costs and economic losses and even premature death. Lumbar spinal fusion (LSF) is a widely adopted surgical procedure for the treatment of persistent LBP, with the aim of relieving pain and increasing functional ability. Over recent decades a substantially increasing number of patients with chronic low back pain (CLBP) undergo LSF in the western world.

Unfortunately, a substantial part of the patients undergoing spine surgery still have persistent pain, functional disability and poor quality of life 4 and 8-10 years after surgery. A report from the Swedish Spine register shows that pain level remains the same 1-5 years after LSF for 25 % of the patients, and consumption of medication remains unchanged in almost 50 % of the patients.

Rationale:

The majority of patients (70 %) planned for spine surgery have fear of movement, and it is well supported in the literature that fear of movement, avoidance coping, negative affect and depression postoperative are associated with persistent pain and function after spine surgery up to 3 years postoperative. Individual differences of pain related coping strategies after LSF also seems to have an influence on the patient's sedentary behavior postoperative.

Research in the field of rehabilitation after LSF have thereby resulted in a growing consensus that a bio-psycho-social approach to rehabilitation is needed. An approach which should start quite early after surgery, and which should focus on the patient's diverse way of living with a disease and the interrelationship between both the biological, psychological and social factors.

A systematic review found that "complex interventions" comprising of exercise and cognitive behavioral therapy offers short and long term functional benefits to patients following LSF. Another RCT confirmed that an early intervention using a cognitive behavioral approach performed by a physiotherapist decreased fear of movement, increased self-efficacy and improved patient-reported and performance-based outcomes in patients after lumbar spine surgery six months after surgery. Research in the field of rehabilitation after LSF call for high quality research to confirm the importance of including an early active approach with a cognitive and behavioral perspective, and advocate for interventions to incorporate the patients context, experiences and thoughts even more in the clinical decision making.

Intervention:

Graded activity is an exercise paradigm which takes a behavioral approach using the principles of operant conditioning. The principles of operant conditioning are to modify negative pain behaviors and disrupt the fear avoidance cycle and thereby increase the patient's physical activity or functioning. Relevant information about pain, healing and the effects of disuse can likely influence what a patient anticipate about movement despite pain. Several studies have investigated the effect of pain education to patients with CLBP and found it efficient. A combination of pain education and exercise for patients with CLBP are furthermore showing promising results. Therefore, a combination of Graded Activity and Pain Education (GAPE) seems to be a suitable approach for early post-operative rehabilitation for patients with LSF, as behavioral, cognitive and physical factors will be addressed in one intervention.

Objective and hypothesis The primary objective of this randomized controlled trial is to examine the effect of an early active intervention consisting of Graded Activity and Pain Education (GAPE) on sedentary behavior in a population of patients undergoing LSF. The secondary objectives are to examine the effect of GAPE on disability, pain, fear of movement, self-efficacy for exercise and health related quality of life.

Inclusion Criteria:

Patients from the Capital Region of Denmark undergoing LSF at Centre for Rheumatology and Spine Diseases, Rigshospitalet, Glostrup from 23st of September 2019 to 30st marts 2021 and fulfilling the following criteria:

1. Low back pain > six months

2. >18 years

3. Undergoing an instrumented spinal posterior fusion of 1-2 spinal segments for degeneration of the lumbar spine, with or without an intervertebral cage placed from the anterior approach, posterior approach or from a lateral access.

   Degenerative conditions include disc herniation, spinal stenosis, spondylosis with or with-out myelopathy and spondylolisthesis.

4. Read and understand Danish

5. Lives no more than 1 ½ hour of transportation from Rigshospitalet, Glostrup

Exclusion Criteria:

1. Has previously been through an LSF
2. One or more of following conditions (infection, neoplasm, metastasis, metabolic bone dis-ease, fractures, post-traumatic vertebral compression/deformity or other known autoimmune arthropathies)
3. Are cognitively or otherwise unable to give informed consent and adhere to the study program
4. Other special conditions where a patient is judged not able to participate in the intervention by the surgeon or researcher (HT) (weakness caused by very high age, extreme poorly functional level, other serious comorbidities)