The study is a parallel-group RCT with three, six and 12 months follow-up. Patients will be randomized 1–2 days post-surgery (1:1) to either usual care or GAPE in addition to usual care.
The trial is reported according to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) Statement (27) (see Additional file 1 and Figure 1).
Study setting
GAPE will be provided by telephone, in the patient’s home, and in the training facilities of the Department of Occupational Therapy and Physiotherapy, Rigshospitalet, Glostrup. At the hospital, the explorative interview will be carried out when the patient is still hospitalized at the Centre for Rheumatology and Spine Diseases.
Patients
Eligibility criteria:
Patients undergoing LSF at the Centre for Rheumatology and Spine Diseases, Rigshospitalet, Glostrup from 1 October 2019 to 31 January 2021 who fulfil the following criteria:
- Low back pain ≥ six months
- ≥ 18 years of age
- Undergoing an instrumented posterolateral spinal fusion of 1–2 levels, with or without an intervertebral cage placed, performed from anterior approach, posterior approach or from a lateral access, for degeneration of the lumbar spine. Degenerative conditions include disc degeneration, spinal stenosis with spondylolisthesis, and substantial spondylosis with or without spondylolisthesis (28)
- Read and understand Danish
- Live no more than 1.5 hours’ travel time by car from Rigshospitalet, Glostrup
Exclusion criteria:
- Previous LSF
- One or more of following the conditions: infection, neoplasm, metastasis, metabolic bone disease, fractures, post-traumatic vertebral compression/deformity, other known autoimmune arthropathies
- Cognitively (or otherwise) unable to give informed consent and adhere to the study programme
- Other special conditions where a patient is judged to be unable to participate in the intervention by the surgeon or PI (HT) (fragile due to very high age, extreme poor functional level, psychiatric disease or other serious comorbidities)
Recruitment, screening and enrolment
All spine surgeons at Rigshospitalet Glostrup will recruit patients to the trial. The surgeons will provide verbal and written information to the eligible patient at the preoperative consultation. If the patient accepts, the PI (HT) will contact the patient by telephone to check inclusion and exclusion criteria. If the patient is interested in participating in the trial, s/he will be invited to a meeting at the hospital with an independent assessor. The independent assessor will repeat information, and if the patient agrees to participate, s/he will sign an informed consent form. The independent assessor will hand out the baseline questionnaire and provide the patient with instructions in how to wear the accelerometer used to measure sedentary behaviour (29). The meeting will be scheduled for the same day as the patient attends a pre-surgery back seminar to lessen burden and time spent by the patients.
Intervention
All patients (intervention and control) will receive usual care pre-operatively and postoperatively from the Department of Rheumatology and Spine diseases and Department of Occupational Therapy and Physiotherapy, Rigshospitalet, Glostrup. An overview of the two groups is shown in Figure 2. The description of GAPE and usual care in this protocol follows the TIDieRs checklist (30).
Control group: Usual care
Pre-surgery:
Before surgery (1–2 weeks), the patient is invited to participate in a pre-surgery seminar, where s/he receives information about the time before, during and after the LSF. The information covers anesthesia, surgery, medication, mobilization and how to use various aids. The seminar will be led by a nurse, surgeon, an anesthesiologist, an occupational therapist and a physiotherapist. The aim of the seminar is to gather the interdisciplinary team in one place for the patients and in this way give the best possible information regarding the surgery-procedure and the time just after surgery. The interdisciplinary team is blinded to patient randomization and the content of GAPE.
During hospitalization:
After surgery, the patient will be hospitalized for an average of three-four days. During hospitalization a physiotherapist consults the patient one to three times to provide information and guidance on mobilization and instructions in gradually progressing movement. The patient will have no restrictions on movement after surgery and is instructed by the physiotherapist to gradually return to their normal activity level. The patient will not receive any specific home exercise programme from the physiotherapist.
After discharge:
Following discharge, the patient consults the nurse after 10–12 days at the outpatient clinic to remove stitches, talk about medication, and to answer any questions s/he might have regarding the period post-surgery. This will be repeated six weeks post-surgery.
Three months post-operatively, the patient will participate in a course of physical rehabilitation delivered by physiotherapists in a local community care centre. The post-surgical rehabilitation offered at the community care centres may vary in content and duration, although a typical course of post-surgical rehabilitation will contain an individual session with a physiotherapist followed by group training, in which the focus will be on stability, strength and endurance of the back muscles. The patient will consult the surgeon at three and 12 months post-surgery, to discuss the surgical outcome, undergo a medical examination and an x-ray monitoring.
Intervention: Usual care supplemented by GAPE
In the intervention group, the patient will receive usual care, as described above, supplemented by GAPE distributed across nine sessions over a 10-week period. As described earlier, GAPE is based on a cognitive behavioural perspective. This builds on the assumption that human behaviour is effected by behavioural, cognitive and affective factors, which include the patient’s perception of and response to pain (31).
The fear avoidance model is one such cognitive behavioural model, recognized for understanding the development of chronic pain (32). GAPE will use a modified version of the fear avoidance model inspired by Woby et al. (33) and Lundberg et al. (35), as shown in Figure 3. The patients’ and physiotherapists’ former experiences, knowledge, and beliefs are factors influencing the patients’ experience of pain and thereby their self-efficacy for exercise and fear of movement.
Components of GAPE
Graded activity:
Graded activity is a technique based on the theory of operant conditioning, and in the area of pain introduced by the American psychologist Wilbert Fordyce in 1976 (35). The aim of graded activity is to improve the patient’s functional ability by positive reinforcement of health behaviours and activity levels (36, 37). By positive reinforcement means reinforcers such as attention, praise, rest from activities and schedules which illustrate occurrence of health behaviour. Graded activity has been tested in physiotherapy settings and has been found effective for the treatment of LBP (21, 38).
In GAPE, the role of the physiotherapist is to capture the patient’s thoughts and beliefs about pain and movement and the consequences of pain in the patient’s social life. The physiotherapist will capture this by an explorative interview (session 1) and observe the patient’s pain and/or health behaviours (sessions 1 and 2). Pain and health behaviours are the patient’s movement strategies despite the pain (e.g., duration of movement, way of moving, resting, breathing, grimacing, etc.).
The patient will be asked to set three-five short-term goals for the next 10 weeks in close collaboration with the physiotherapist (session 2) (39). The goals should involve physical activities that are specific, measurable, achievable, realistic, and time-targeted (SMART goals). The goals will be registered on the Patient Specific Function Scale (PSFS) and will be the focal point for the activity/exercise programme which the physiotherapist plans for the patient (40, 41).
The patient’s current baseline tolerance level of each activity/exercise in the programme will be tested. Quotas will be set for the activities/exercises, balancing between the baseline tolerance level, the load of activities, and the knowledge provided through the interview and observation of the patient (35, 40). Quotas will be lower than baseline tolerance level, to secure a positive experience of performing the programme, and to give the patient a sense of being in control. In subsequent sessions, quotas are systematically increased.
Pain education:
The patient will have 1 session of pain education in GAPE (session 2) (42). The underlying theoretical model for pain education is the modified fear avoidance model (Fig. 3), as an approach to challenging the patient’s maladaptive pain cognition and to modify beliefs about movement despite pain (23, 43). The pain education will target four overall questions:
- What is pain?
- Is my pain normal?
- What can affect my pain?
- What can I do to relieve my pain?
The pain education will be individually adapted to each patient, so the patient’s context and concerns regarding pain and movement are included. The educational material will be in the form of laminated worksheets. The educational material illustrates a simple explanation of the neurophysiology behind pain and suggestions of ways to manage pain in everyday life.
The outlined intervention in GAPE
The outlined intervention will start just before discharge (session 1), and the final session (session 9) will take place 10 weeks postoperatively. The sessions will be held at the hospital, in the patient’s home and by telephone. The nine sessions are outlined in additional File 2. Each session will be followed by home exercises matching the patient’s goals and quotas. The patient will be responsible for performing the programme until following session is scheduled.
To improve adherence to the intervention, some of the sessions are placed on days where the patient is going to the usual check-up visit with the nurse at the hospital (sessions three and seven). Furthermore, three sessions (sessions four, six and eight) will be of shorter duration and delivered by telephone.
Each intervention session will be registered by the physiotherapist as completed/not completed, to control for compliance to the scheduled intervention sessions.
Physiotherapists’ training to deliver the intervention:
Four physiotherapists from the Department of Occupational and Physiotherapy, Rigshospitalet, Glostrup will perform the intervention (including the PI, i.e. HT). All physiotherapists managing the GAPE intervention have over six years of experience in treating patients with complex LBP based on a cognitive behavioural perspective.
To attain skills in delivering graded activity, the physiotherapists have attended three training sessions with the PI (HT). During the sessions, theory and specific management approaches for graded activity will be discussed and a training manual handed out (44). Each physiotherapist will have observed the PI (HT) perform graded activity during an intervention period of one patient each (sessions 1 to 9). Furthermore, HT will supervise the three physiotherapists throughout the intervention period to ensure that the GAPE manual is followed.
To attain skills in delivering pain education, the physiotherapists will attend a course in pain mechanisms and pain education ("Basic course in Pain Neuroscience”) (42). The physiotherapists will also participate in a 1-day refresher course regarding pain theory and discuss and agree upon the exact pain education to be delivered in the intervention.
To ensure further treatment fidelity, all physiotherapists will be supervised by an experienced psychologist with expertise in the psychological treatment of chronic pain. Each physiotherapist will be supervised by the psychologist during one of their patient interviews (1st session). After two months the psychologist will undertake a group supervision (lasting three hours) again for intervention fidelity.
Criteria for discontinuance
Patients allocated to the intervention group will be discontinued if he/she:
- Withdraws his/her consent
- Is scheduled for re-surgery
- Falls ill during the intervention period in such a way that it is not possible to continue the intervention.
Outcomes and assessment
Data will be collected on four occasions during the trial: at baseline and at three, six, and 12 months post-surgery (see also Additional File 3). Patient-reported outcomes (PROs) will be completed at the hospital at baseline and at three and 12 months follow-up, using an online data capture application (REDCap) (45). At six months follow-up the patient will receive an email with a link also via REDCap.
To prevent missing data, non-responders will be contacted by telephone shortly after data collection time-points at three, six, and 12 months follow-up, with a maximum of two reminders by email.
Primary outcome measure
The primary outcome is “reduction in sedentary behaviour” and will be measured at three months post-surgery. Sedentary behaviour will also be measured at 12 months follow-up as a secondary outcome.
Sedentary behaviour will be defined as: “Any waking behaviour characterized by a sitting or reclining/lying posture” (46). Sedentary behaviour will be assessed objectively as the number of minutes per day the patient is sedentary (lying down and sitting) measured with the SENS motion activity measurement system (29). SENS is a small accelerometer placed within a small plaster to be worn discretely on the patient’s thigh (Figure 4). The SENS motion system is considered a reliable and valid device for measuring sedentary behaviour (47). The patients will wear the accelerometer for seven consecutive days during the week before surgery, and for seven days at three and 12 months post-surgery.
Secondary outcome measures
Disability will be measured using the Oswestry Disability Index (ODI). ODI measures condition-specific disability, and was developed for patients with LBP (48). The Danish version of ODI has shown acceptable responsiveness, reliability, and validity (49, 50). The ODI consists of ten items, covering pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sex life, social life, and travelling. For each item, the patient chooses one of six answers, with 0 representing no difficulty in the activity and 5 representing maximal difficulty (49–51).
Pain in the back and legs is assessed using a visual analogue scale (VAS) with a possible score of 0 ('‘no pain’') to 100 (“the worst pain imaginable”) (52, 53). The wording in the questionnaire is "Indicate your pain level for the past week by a mark on each line below, as shown in the example. The far-left side of the line corresponds to pain-free and the far-right corresponds to the worst possible pain. By placing a mark on the line you register how your pain has been within the past week”.
Fear of movement will be assessed using the 11-item short version of the Tampa Scale of Kinesiophobia (TSK–11). The TSK–11 has shown satisfactory validity, reliability and responsiveness in a surgical spine population and in patients with chronic pain (9, 54). Respondents are asked to indicate to what extent the items are a true description of the assumed association between movement and (re)injury on a 4-point Likert scale, ranging from strongly disagree to strongly agree.
Health-Related Quality of Life will be assessed using the EuroQol 5 Dimensions three levels (EQ–5D–3L) (55). EQ–5D–3L consists of the following five dimensions: Mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension is divided into three levels: no problems, some problems or extreme problems. EQ–5D–3L also includes a 20-cm vertical scale, were the respondent is asked to describe his/her own health with endpoints of ‘best imaginable health state’ set at 100 and ‘worst imaginable health state’ set at 0 (56). The EQ–5D–3L has been validated in Danish, including the development of preference values (57) and Danish population norms (58).
“Self-efficacy for exercise” will be assessed using the questionnaire Self-efficacy for Exercise Scale (SEES). The SEES consists of nine items that measure how confident the patient is in doing exercise under different circumstances. The total range is from 0 to 90 points, where higher scores indicate a higher degree of self-efficacy for exercise. SEES has been found valid and reliable in a Scandinavian population (59).
Additional information
The following data will be retrieved from the patient’s (a) medical record and (b) a questionnaire developed for this trial.
Information from the patient’s electronic medical record will be: sex, age, diagnosis and type of surgery (transforaminal lumbar interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF), posterolateral fusion (PLF), oblique lateral interbody fusion (OLIF), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF)). Comorbidity will be registered using the Charlson comorbidity index (CCI) (60, 61).
Information from the questionnaire will be:
- Baseline data: height, weight, smoking, alcohol intake, employment, education status and previous spine surgery.
- Satisfaction with the results after surgery: satisfaction will be used to evaluate the patient’s satisfaction regarding the achieved movement and pain after surgery. Patients will be asked to assess both their capacity to move their back and whether they feel safe moving their back on a VAS. The far-left side of the line corresponds to “very satisfied with my capacity to move my back post-surgery” and the far-right corresponds to “Not at all satisfied with my capacity to move my back post-surgery”. Regarding pain, patients will be asked to compare back/leg pain before surgery until now. The patient can mark in five boxes, from “The pain has disappeared” to “The pain has worsened”. The patient will also be asked to evaluate the overall result of the operation, from “Satisfied” to “Not satisfied”.
- Adverse events: Adverse events are defined as limitations in daily activities, sport activities or work limitations, together with symptoms that cause patients to seek medical care. The events may be unrelated to the back (such as development or exacerbation of comorbidities) and the events are not necessarily causally linked to the LSF. The adverse events will be self-reported using a line with ample space for free text.
- Received guidance/training in physical exercise: To control for the received guidance/training in physical exercise during the time after surgery, both groups will be asked if they have received any guidance/training regarding physical activity, from whom, and the content, amount and duration of exercise.
Randomization
Accordingly, one to two days after surgery, the patients will be allocated in a 1:1 ratio to either usual care (control group) or usual care together with GAPE (intervention group), taking into account type of LSF (posterior versus anterior surgery approach) and smoking habits (i.e. block-randomization). A co-investigator (MH) will be in charge of setting up the block-randomization, whereas the actual randomization of the patients will be administered by HT (see Figure 5, Flow diagram).
Allocation and blinding
The patient will receive the allocation number just before discharge, so health professionals administering the usual postoperative care during hospitalization (surgeons, nurses, occupational therapists and physiotherapists) will be blinded to randomization. The group allocation numbers will be delivered in sealed envelopes by HT.
Two blinded assessors (physiotherapists) will collect informed consents and will be responsible for the entire outcome assessment (at baseline pre-surgery and at three, six, and 12 months follow-up). These assessors will be trained by HT in requirements of the trial and the standardized measurement procedures, including a manual for the procedures in the trial.
Due to the nature of the intervention, neither the patients, the intervention physiotherapists nor the PI will be blinded to group allocation.
Analyses
Sample size
The power calculation is based on the primary outcome, sedentary behaviour. A mean difference of 60 minutes per day is considered a clinically significant difference, with a standard deviation of 115 (62). A sample size of 59 per group is required to obtain a power of at least 80% to detect the mean difference of 60 minutes. To account for a 20% drop-out, we will include 144 patients in total.
General statistical approach
A detailed statistical analysis plan (SAP) will be produced before enrolment of the last patient.
Assessments of outcomes and construction of confidence intervals (CIs) for continuous measures will be based on an analysis of covariance (ANCOVA; including group as the main factor and baseline measure as covariate).
Superiority will be claimed if the computed 95% CI of the estimated group difference in the time spent in a sedentary position does not include 0 in the intention-to-treat (ITT) population.
All statistical tests will be two-sided and statistical significance will be claimed if the computed p-value is equal to or less than 0.05.
Analysis of population sets:
For the assessment of superiority, we will use the ITT population in the primary analysis, as it is the most conservative approach.
Study population definitions:
ITT population:
This consists of all randomized patients in the groups to which they were randomly assigned, regardless of the treatment they actually receive.
Per-protocol (PP) population:
All patients that adhere to the planned protocol, defined by the following criteria for the two groups:
Intervention-group (GAPE) has:
- a baseline measurement, AND
- at least one post-baseline measurement (three, six or 12 months post-surgery), AND
- attended the first two sessions at the hospital and in the patient’s home, respectively (sessions 1 and 2), AND
- attended at least two of the scheduled graded activity appointments; this does not include telephone sessions (a GAPE intervention attendance record will be used for documentation)
Control group (Usual care) has:
- a baseline measurement, AND
- at least one post-baseline measurement (three, six or 12 months post-surgery), AND
- has not received other kinds of active cognitive behavioural treatment during the first three months post-surgery.
Data management
The blinded assessor will give each participant a trial identification number and all data will be de-identified. The identification list with participant information and trial study number will be kept in REDCap. HT and MH will have access to the final dataset in REDCap. The signed consent will be kept in locked filing cabinets behind double locked doors.
Risks, side effects and inconvenience
Participation in the trial is expected to be associated with a minimal risk of side-effects. The project is planned so that hospital visits should disturb the patients as little as possible. The patients will have to visit Rigshospitalet, Glostrup 1–2 extra times and documented travel expenses will be refunded on request (63).
Former studies of early post-surgical rehabilitation following LSF have not reported any risks or side effects (18). In addition, co-investigator, spine surgeon RBA, has assessed the intervention description for any possible risks regarding the fusion material, and does not consider that the GAPE intervention entails an increased risk of stress on the pedicle screw fixation system. In the event that any patient shows signs of new neurological symptoms, such as paresis, unexpected worsening of preoperative lumbar or radicular pain or sensitivity changes, or unexpected changes in the surgery wound during the intervention period, the physiotherapist will contact the surgeon.
Regarding the SENS accelerometer, this might entail some discomfort, when the accelerometer is removed, similar in magnitude to taking off normal plaster. Furthermore, there is a small risk of allergic reaction to the plaster holding the SENS accelerometer. Patients will receive specific skin care advice if this should happen.
Patients are covered by the “Patient-compensation agreement”, if anything unexpected should happen during the intervention.
Patients included in the project cannot participate in other kinds of research projects with active interventions or receive other kinds of active cognitive behavioural treatment during the first three months post-surgery. This is to ensure that the intervention and the control group are comparable and only differ by the GAPE intervention being evaluated.
Patient involvement in the study
Prior to the development of the GAPE intervention, HT conducted semi-structured informal interviews with five volunteer patients—both immediately after LSF and one month postoperatively. The interviews were performed to include the patients’ perspective of pain, movement and thoughts after LSF, and to incorporate their ideas of an ideal early postoperative intervention.
To ensure that the patient’s perspective remains a vital part of this project, a patient operated in 2015 with LSF, has agreed to participate as a patient research partner (PRP) throughout the entire project period. The PRP has read, commented on and approved the participant information. Furthermore, on several occasions the PRP has commented on drafts of the intervention and the choice of outcomes.
The outlined intervention has also been pilot tested by HT on four patients with LSF.
Dissemination
The outlined project is expected to produce three scientific articles in internationally peer reviewed journals, whether the results be positive, negative or inconclusive. Additionally, results of the project will be communicated in both academic and public fora.