Presurgical rehabilitation program for patients with symptomatic lumbar spinal stenosis: A pilot randomized controlled trial protocol

ABSTRACT Background Symptomatic lumbar spinal stenosis (SLSS) is the most common diagnosis associated with spine surgery for those over the age of 55 years. There is a lack of quality research on the effectiveness of prehabilitation on pain, function, and quality of life in patients undergoing surgery for SLSS. This pilot randomized controlled trial (RCT) will evaluate the feasibility of an eHealth prehabilitation program for individuals undergoing SLSS surgery, and an embedded longitudinal qualitative study explores the perioperative patient experience and recovery trajectory. Methods Participants (n = 60) undergoing spine surgery for LSS will be randomized into the 8-week electronic health (eHealth) prehabilitation program or minimal intervention. The prehabilitation program will be delivered virtually using synchronous (one-on-one) and asynchronous (independent) sessions by an experienced clinician, consisting of motivational interviewing, exercise (graded activity), education, peer support groups, and a 6-week booster session. Participants in the minimal care group will receive usual care and will have access to educational videos. Primary outcomes will include (1) recruitment, (2) patient adherence, (3) acceptability of program content, (4) acceptability and compliance with study questionnaires, and (5) attrition. Outcomes will be assessed at baseline, after the intervention, and 3 and 12 months postoperatively. We will conduct semistructured interviews alongside the RCT with 12 to 15 participants. Discussion The proposed project will include the feasibility testing of an eHealth LSS prehabilitation program with potential to improve surgical outcomes. Results of this study will provide the foundation for future fully powered multicenter RCTs. Trial Registration clinicaltrials.gov NCT05073081


Background
Symptomatic lumbar spinal stenosis (SLSS) is a lower back condition that occurs with increasing age and is considered one of the most burdensome spinal conditions. 1 It is estimated that nearly 10% of individuals over the age of 60 experiences LSS. 2 Due to the aging population, it is expected that the prevalence of SLSS will increase by 30% by the year 2031. 3 LSS is characterized by degenerative changes leading to loss of intervertebral disc spaces, joint thickening, and enfolding of the ligaments surrounding the spine. 4 These anatomical changes may cause compression of the spinal cord or nerves, which consequently leads to neurogenic claudication. 5 SLSS, in particular neurogenic claudication, is associated with cramping, numbness, tingling and pain in the leg or lower back, significantly diminished functional capacity, and reduced quality of life. 6,7 There are no clear pathways for management for individuals with SLSS, but the majority of patients often receive conservative interventions that include rehabilitation, steroid injections, and opioids. 1 Lumbar spine surgery is often recommended when there are severe symptoms and functional decline and when conservative management has failed. 1 In fact, SLSS is the most common diagnosis associated with spine surgery in those over the age of 65. It is estimated that approximately 30,000 Canadians undergo spine surgery each year, 8 and this number is increasing. 9 The total per patient cost (at a median of 5 years after surgery) for spinal decompression and spinal decompression with fusion is estimated to be $5754 and $20,856, respectively. 10 Additionally, the median fifth-year incremental cost-utility ratio was estimated to be $12,271/quality-adjusted life year (QALY) for spinal decompression and $35,897/QALY for spinal decompression with fusion. 10 Though the costs associated with spine surgery are below the commonly used threshold of $50,000/QALY for acceptable cost-effectiveness interventions, up to 30% of patients undergoing surgery continue to experience significant pain and disability, have reduced quality of life, and use narcotics postoperatively. 11,12 A recently published systematic review has provided evidence that more than 40% of individuals undergoing lumbar spine surgery remain long-term opioid users. 13,14 Poorer postoperative outcomes have been associated with preoperative risk factors that include chronic opioid use, poor expectations of pain recovery, depression, longer pain duration, worse disability, reduced quality of life, and poor walking capacity. [15][16][17] Identifying and implementing strategies to address modifiable risk factors prior to surgery may improve postoperative outcomes.
Given the high prevalence and economic burden of SLSS, as well as poor surgical outcomes, there has been an increasing interest in identifying strategies to improve patients' surgical outcomes. In Canada, many patients undergoing spine surgery can wait for up to 1 year for a surgical appointment and another year for their surgery. 18 This vulnerable group of patients (older adults with chronic pain) is usually severely deconditioned by the time of surgery, which puts them at greater risk for poorer outcomes. Thus, presurgical rehabilitation (prehabilitation) aimed at preparing patients physically and mentally to undergo surgery has received significant attention over the last few years. 19 A recent systematic review of 15 studies evaluating the effectiveness of prehabilitation for individuals undergoing lumbar spine surgery for a myriad of degenerative disorders found that programs primarily focused on cognitive behavioral therapy (14 studies) were no more effective than usual care in regards to pain, disability, and quality of life. 19 In this review, only one study focused on exercise therapy preoperatively and found a positive effect on short-term physical functioning and reported a shorter length of hospital stay postoperatively. Additionally, the authors of the review concluded that there is a lack of good quality evidence for pain and functional outcomes, as well as lack of clarity on postoperative effects based on type of surgical approach. As such, there is a need to conduct high-quality research that assesses the effectiveness of prehabilitation on clinical outcomes of individuals undergoing surgery for SLSS.
There are significant benefits to the introduction of electronic health (eHealth) interventions, including the provision of care to remote locations that lack access to health care services. Further, considering that patients with LSS about to undergo surgery have significantly mobility limitations, eHealth interventions have the potential to decrease burden for patients and caregivers and reduce time and money associated with travel. 20,21 In addition, eHealth interventions have the potential to address the complex needs of patients who are waiting for surgery (waitlists vary from 6 months to 2 years). They may help decrease fears and anxiety regarding surgery, increase satisfaction with care, and improve preoperative function and postoperative recovery. Given the SARS-CoV-2 (COVID-19) pandemic, there has been an urgent shift in the transition to eHealth rehabilitation interventions (e.g., phone app, computer, etc.). A recent study assessing satisfaction with eHealth interventions in spine care rehabilitation found that patients identified these interventions as very effective and satisfactory. 22 An ongoing Cochrane review assessing the effect of eHealth programs for low back pain found very low certainty evidence that eHealth interventions are superior to usual care for both pain intensity and disability in the intermediate-term follow-up (6 months). 23 Therefore, this study proposes the use of an eHealth prehabilitation program for individuals undergoing lumbar spine surgery for SLSS.
We have developed a comprehensive, patientcentered eHealth prehabilitation program that combines exercise, motivational interviewing, peer support groups, and principles of cognitive behavioral therapy. The intervention was developed in collaboration with patient partners with lived experience with SLSS surgery and a transdisciplinary health care team (i.e., surgeons, physiotherapists, chiropractors, exercise physiologists, physiatrists, and rehabilitation researchers) and current scientific literature. [24][25][26] This patient-centered prehabilitation program has the potential to improve postoperative pain, function, and patient-oriented outcomes and decrease postoperative opioid use and short-and longterm health care costs.
Before moving ahead with a fully powered randomized controlled trial (RCT), we aim to complete a pilot RCT to test the feasibility of the intervention and study protocol. Primary feasibility outcomes will be recruitment and retention of patients, given the difficulties that may arise from sampling a surgical and older adult population. Given the longitudinal design of this study, attrition is important to consider in a future study. Additionally, we anticipate some technological challenges given that research outcomes will be collected through online surveys, and the intervention will be delivered virtually.
The study will aim to answer the following research questions: (1) What is the acceptability and satisfaction with the eHealth prehabilitation intervention for individuals undergoing SLSS surgery? (2) How feasible is the eHealth prehabilitation program in terms of recruitment rate, adherence rate and retention rate, and participant burden? (3) What are barriers and facilitators to the program and the trajectory of recovery of patients following SLSS surgery?

Methods
This study will use a concurrent embedded mixed methods design including a quantitative strand and a qualitative strand to evaluate the feasibility of an eHealth prehabilitation program for persons with SLSS. 27 The quantitative strand will be a two-armed, pilot RCT evaluating an 8-week eHealth prehabilitation program for participants undergoing SLSS surgery versus a minimal intervention group who receive education only. The qualitative strand will comprise a longitudinal qualitative study conducted parallel to the pilot RCT. This trial has been registered on clinicaltrials.gov (Registration No. NCT05073081).

Ethical Considerations
This application has been reviewed by the Health Ethics Research Board at the University of Alberta (Project #RES0052621) and the Hamilton Integrated Research Ethics Board (Project #13,167).

Quantitative Strand: randomized Controlled Trial
This parallel RCT study will include two arms: (1) eHealth prehabilitation program and (2) minimal intervention of education only.

Recruitment/Sites
Recruitment for this study will take place across four different surgical centers (Hamilton General Hospital, University Health Network, Alberta Royal Alexandra Hospital, and Foothills Medical Center) across Canada. It is expected that recruitment will take approximately 12 months given COVID-19 restrictions and limitations on surgical procedures.

Participants
A sample size of 60 participants, recruited in Ontario (Hamilton: Hamilton General Hospital and Toronto: University Health Network) and Alberta (Edmonton: Royal Alexandra Hospital and Calgary: Foothills Medical Center). The sample size for this pilot study is of convenience and based on recommendations for pilot studies based on a two-armed trials rule of thumb. 28,29 Given the objectives of this study, a sample size of 30 per province will be adequate to evaluate feasibility. Participants will be included in the study if they (1) are a minimum 20 weeks before their date of surgery, (2) are older than 55 years of age, (3) are scheduled for first spine surgery for SLSS, and (4) have basic English comprehension to complete the study questionnaires. Participants will be excluded if they (1) have a known or suspected pathology (e.g., cancer, cauda equina syndrome), (2) are unable to engage in exercise due to other comorbidities or cognitive issues, (3) do not have access to the Internet, or (4) undergo multiplelevel fusion (more than two levels) or an anterior surgical approach during SLSS surgery. Baseline limitations may be higher for those undergoing multiplelevel fusion (more than two levels) or using the anterior surgical approach, leading to different recovery periods that would require a much larger sample to address variation.

Randomization
The randomization sequence will be created by a statistician who is not involved with other components of the study and will include permuted blocks (two, four, and six blocks) and stratification by site (Hamilton, Toronto, Edmonton, and Calgary). Randomization (1:1) will be performed using REDCap by the treating therapists after informed consent and baseline assessment.

Sources of Bias
Blinding of participants and those delivering the intervention is not possible within an exercise/rehabilitation trial. Further, assessors will not be blinded given that outcomes are self-reported.

Prehabilitation Intervention
The proposed program was developed using best available evidence, results from our preliminary work (manuscripts under review), and in collaboration with patients and our multidisciplinary team ( Table 1). The intervention will be reported using the Consensus on Exercise Reporting Guidelines. 30 All participants will be prescribed exercises (by either a chiropractor or physiotherapist) over a period of 8 weeks using the commercially available web-based Physitrack exercise programming application (https://www.physitrack.ca). Physitrack is a commercially available cloud-based digital platform that allows health professionals to assign exercise programs and education to individuals remotely and allows for videoconferencing. All data sent to and from the Physitrack platform are encrypted. Access to patient data is severely restricted and any person or party that has access to Physitrack patient data is bound by confidentiality agreements. Physitrack provides network security through a virtual private cloud, a bastion host, a firewall, and IP address filtering. The prehabilitation program will consist of synchronous (five one-on-one exercise sessions at 1, 3, 5, and 7 weeks, 6 weeks postoperatively with a clinician) and asynchronous (independent) home exercise sessions (minimum three times a week). The initial synchronous (one-on-one) session with the clinician will include a structured baseline assessment of mobility and balance.
Prehabilitation will consist of exercises and a walking program that will be delivered using graded activity, 31 other cognitive behavioral therapy principles, 32 and motivational interviewing. 33 With graded activity, principles of operant conditioning are used to reinforce healthy behaviors. 31 The program will focus functional activities and goals, identified by the participant at baseline, and progress in a time-contingent manner regardless of pain to achieve functional goals and increased activity. Principles of quotas, pacing, and selfreinforcement are key features of the program. To achieve functional goals, exercises may incorporate global muscle strengthening and stretching, with a focus on improving walking capacity, trunk strength, and general body muscle strength.
Participants will receive educational videos, developed by the research team, through eight short online videos (3-5 minutes). The educational program will include pain education, 34,35 self-management, 35 pacing, 31,36 postoperative expectations, exercise recommendations, and information regarding their upcoming surgery. Educational videos will be provided on Physitrack (asynchronously) at the start of each week (Weeks 1-3: Understanding Your Spinal Stenosis, Parts 1, 2, 3; Week 4: Managing Your Spinal Stenosis with Exercise and Physical Activity; Week 5: Tips and Tricks for Exercise with Spinal Stenosis; Week 6: Self-Managing Your Spinal Stenosis; Weeks 7 and 8: Surgical Expectations). The program will also include online peer support groups, which was indicated to be an important aspect of prehabilitation from our previous qualitative research (manuscripts under review). These peer support groups will be led by our patient partners, which will provide an opportunity for participants to engage with an individual who has lived experience with LSS and surgery. Peer support group sessions will occur every 4 weeks and participants will have the opportunity to attend two sessions.

Minimal Intervention
Participants in both the minimal intervention and prehabilitation groups will continue to receive preoperative care as per usual clinical practice. This generally consists of one preoperative session with an anesthesiologist and a nurse to discuss the surgery, including a pamphlet regarding preand postoperative instructions and recommended exercises. Participants in the minimal intervention group will also have access to the educational content shared with the prehabilitation group to ensure standardization of treatment.

Training
Clinicians (chiropractor or physiotherapist) who will deliver the intervention underwent a 1-day 4-hour training workshop. The workshop, titled Choices and Changes: Motivating Healthy Behaviours, was developed and implemented by the Institute for Healthcare Communication. 37 The purpose of this training was to provide clinicians with Table 1. Overview of the prehabilitation intervention.

Prehabilitation Intervention
Week 1 • Initial assessment with clinician prior to the start of the intervention • Motivational interviewing at each synchronous clinical interaction • Therapist will help identify treatment goals (action planning). Participants will be asked to identify three achievable goals (what), identify how much they want to achieve in terms of frequency and intensity (how), identify when they will do the activity (when), and rate their confidence in successfully completing the activity (confidence). Participants will be asked to rate their confidence in completing their goals on a scale from 0 to 10 and modify their goals if their confidence is <7.
• Therapist will conduct baseline assessment of exercise capacity to determine the patient's capability. This will also include pain levels during the activity. Initial levels of activity should be set at 60%-75% of capacity or when pain increases greater than 2 points on a 0-to 10-point scale (where 0 is no pain and 10 is the worse pain possible). Baseline levels will be set in a discussion with the patient using motivational interviewing principles.
• Therapist will prescribe exercises to the patient based on defined goals (e.g., carrying a garbage can, going up the stairs); segmentation may be important (e.g., work on quadriceps strength when goal is lifting).
• Each exercise will be completed at 10-12 repetitions for three sets. The program should lead toward independence and, thus, the goal is to exercise at least three times a week at home.
• Patient to continue with individualized home exercise plan asynchronously • Educational content: Understanding Your LSS Part 1 Week 2 • Patient to continue with individualized home exercise plan asynchronously • Educational content: Understanding Your LSS Part 2 Week 3 • Therapist and patient will review goals to ensure timely progression of exercises through a synchronous session.
• Therapist and patient will discuss any challenges experienced and modify exercises accordingly.
• Motivational interviewing at each synchronous clinical interaction • Patient to continue with individualized home exercise plan asynchronously • Educational content: Understanding Your LSS Part 3 Week 4 • Patient to continue with individualized home exercise plan asynchronously • Educational content: Managing LSS with Exercise and Physical Activity • Peer café 1 a Week 5 • Therapist and patient will review goals to ensure timely progression of exercises through a synchronous session.
• Therapist and patient will discuss any challenges experienced and modify exercises accordingly.
• Motivational interviewing at each synchronous clinical interaction • Patient to continue with individualized home exercise plan asynchronously • Educational content: Tips/Tricks for Exercise with LSS Week 6 • Patient to continue with individualized home exercise plan asynchronously • Educational content: Self-Managing Your LSS Week 7 • Therapist and patient will review goals to ensure timely progression of exercises through a synchronous session.
• Therapist and patient will discuss any challenges experienced and modify exercises accordingly.
• Motivational interviewing at each synchronous clinical interaction • Patient to continue with individualized home exercise plan asynchronously • Educational content: Surgical Expectations Week 8 • Patient to continue with individualized home exercise plan asynchronously • Therapist will discharge patient from the intervention. • Therapist will advise patient to continue with the exercise postoperatively.
• Educational content: Surgical Expectations • Peer café 2 a Post-Op (6 Weeks) Booster • Therapist will review patient progress and provide exercise advice as needed. a Participants will be invited to attend two peer cafés: cafés will run every 4 weeks continuously and thus all participants will be able to attend two cafés. These cafés will be an opportunity for participants to interact with peers who are either undergoing the prehabilitation program or have completed their surgery. These sessions will be led by a patient partner with lived experience with LSS surgery. tools and strategies to motivate patients' health behaviors and improve adherence to treatment recommendations. Clinicians delivering the intervention have 3 to 4 years of experience in prescribing exercise and rehabilitation therapy. To ensure fidelity between clinicians, the principal investigator will drop in on a session and review patient charts. Patient partners involved in providing the peer support group sessions also underwent a 2-hour peer support training session that was developed by the research team. This workshop included information on what peer support is, the importance of peer support, the core values of peer support (e.g., mutuality, dignity, trust, etc.), and overview of pre-and postoperative SLSS surgery, as well as an example of a peer support session. [38][39][40][41][42][43] Outcomes Outcomes will be evaluated at four time points: at baseline (~20 weeks before SLSS surgery), immediately after the intervention (8 weeks), and 3 and 12 months postoperatively. All outcomes will be collected through online surveys using the REDCap platform.

Demographic and Clinical Information
We will collect demographic and condition-specific information that includes sex/gender, age, ethnicity, marital status, weight, height, history of lower back pain, education, employment history, and medication and interventions used to manage lower back pain.

Outcome Measures
Feasibility outcomes are (1) recruitment rate, (2) patient adherence to the program and attrition rates, (3) acceptability of program content, and (4) acceptability of study procedures and completion of study questionnaires. A priori cutoffs for feasibility have been established and are presented in Table 2. Patient-reported outcomes will be used to inform feasibility and study burden.

Disability
The Oswestry Disability Index (ODI) is a ten-item scale that will be used to assess functional disability. 44 The  Burden of study questionnaires will also be assessed by percentage of data completion if each questionnaire.

Qualitative results
A main theme of acceptability and satisfaction is identified in the analysis of transcripts regarding program content and format of delivery.
ODI is a disease-specific questionnaire designed to evaluate pain and function in patients with lumbar spinal stenosis. 45 The ODI has been shown to have high testretest reliability (r = 0.83 and 0.89), high internal consistency (Cronbach's alpha = 0.71 and 0.87), and high concurrent validity with other pain measures such as the visual analog scale (VAS; r = 0.62) and Roland-Morris scores (r = 0.77). 44 The ODI has also been shown to have good responsiveness measured by the minimum detectable change (12.67), the effect site (0.53), the standardized response mean (0.80), and anchor-based methods (receiver operating characteristic curves: 0.71). 46

Pain
Back and leg pain will be assessed using a numeric rating scale (NRS). 45,47 The NRS for the measurement of pain has shown to have high test-retest reliability in patients with LSS (intraclass correlation coefficient [ICC] = 0.52 for back or buttock symptoms and ICC = 0.49 for thigh/ leg symptoms). 45 The NRS has been shown to be highly correlated to the VAS in patients with chronic pain conditions, with correlations ranging from 0.86 to 0.95. We will assess pain using three questions: average pain over the past week, worst pain in the last 24 hours, and average pain in the last 24 hours. 48

Balance
The Balance section (three items) of the Swiss Spinal Stenosis Questionnaire will be used to assess balance. 49 The test-retest reliability has been shown to be high for the Swiss Spinal Stenosis Questionnaire with an ICC of 0.92 and internal consistency with a Cronbach's alpha of 0.91 in this patient population. 50

Health-Related Quality of Life
The 12-Item Short Form Health Survey (SF-12) is the most recommended scale to assess quality of life in patients with LSS 51 and has been shown to have good reliability, validity, and responsiveness. [52][53][54] The SF-12 will be assessed based on the two subscales (Mental Health, MCS12, and Physical Health, PCS12). In addition, the European Quality of Life Five Dimension (EQ-5D) will be used because it has been shown to assess important aspect of health in patients with LSS. 55

Psychological Measures
A significant component of our intervention will address beliefs, fear of movement, and the psychosocial aspects of LSS. We will use the following validated measures: • Patient Health Questionnaire Depression Scale (PHQ-9): a nine-item scale that has been used to assess depression in patients with LSS. 56 The PHQ-9 has been shown to be a reliable and valid measure of major depression, with a PHQ-9 score ≥10 having a sensitivity of 88% and a specificity of 88%. 57 • Pain Catastrophizing Scale (PCS): a 13-item scale used to identify attitudes and behaviors toward low back pain. 58 The PCS has high internal consistency with a Cronbach's alpha of 0.92. 59 The PCS has also been shown to have a high correlation with perception of pain severity (r = 0.51), 59  item scale used to evaluate kinesiophobia and associated activity anxiety. 63 The questionnaire has been shown to have good concurrent validity (ranging from r = 0.33 to 0.59) and test-retest reliability (ranging from r = 0.64 to 0.80) in patients with chronic musculoskeletal pain, including lumbar spine pain. 64 • We will also include questions developed by the research team regarding satisfaction with specific components of the intervention and the platform used using a numerical rating scale.

Adherence Diary
Given that there is no gold standard to measure exercise adherence and a lack of evidence surrounding selfreported questionnaires, adherence will be measured using a weekly diary. 65 Participants will be given a handwritten weekly diary and will be asked to record the number of times per day they completed each of the recommended exercises.

Monitoring Variables
Adverse events will be collected by a weekly patient diary and during the synchronous (one-on-one) sessions. A serious adverse event will be defined as an event leading to death, hospitalization, or serious deterioration in health. 66 A nonserious adverse event will be defined as pain, fatigue, or edema. Co-interventions (e.g., medication, manual therapy, etc., exercise adherence (e.g., accelerometry, self-reported exercise diary, online metrics from Physitrack) will also be collected.

Accelerometry Physical Activity
An important aspect of symptomatic LSS is its impact on walking ability and daily pain. Thus, we have included an ecological momentary assessment, using activity monitors to evaluate physical activity, pain, and fatigue. Ecological Momentary Assessment (EMA) involves repeated sampling of participants' current behaviors and experiences in real time in their natural environment. 67 EMA was highlight advocated by our patient partners. Total weekly minutes of physical activity will be captured with a wearable triaxial accelerometer device (Actiwatch Spectrum Pro Startup, Philips, USA) worn for seven consecutive days. 68 This battery-powered device records time-varying accelerations, which provide an accurate assessment of physical activity across different dimensions (e.g., frequency, intensity, and duration) and domains (occupation, domestic, transportation, and leisure time). 68 We will collect information on maximum time of continuous activity, volume of activity (total activity counts/week), intensities of energy expenditure, and maximum intensity (maximum number of activity counts/minute).
In addition to providing data on daily physical activity, the Actiwatch allows for two questions (pain and fatigue) to be asked on a 0-10 rating scale (0 = no pain/fatigue, 10 = worst imaginable pain/fatigue) and is programmed with a reminder alarm. Participants will be asked to rate the severity of their pain and fatigue three times per day for 7 days. This unidimensional single-item measure of pain intensity and fatigue has been used in adult populations and is reliable and valid. 69,70 Participants will wear the activity monitor for 7 consecutive days before the beginning of the intervention, at the end of the intervention, and at 3 months of follow-up. The Actiwatch will be either mailed to the participant, including a stamped return envelope, or will be delivered to each participant by a member of the research team.

Qualitative Strand
For the qualitative component, we will follow an interpretive descriptive approach for qualitative studies. [71][72][73] Developed by Sally Thorne, interpretive description is a research design that allows researchers to use an inductive approach to assess clinically relevant knowledge connected with the health care setting. 73 More specifically, the researchers can examine a particular clinical objective (i.e., implementation of the SLSS prehabilitation program) in a specific context (i.e., eHealth).
We will use purposive sampling to conduct in-depth semistructured qualitative interviews at baseline (~20 weeks before SLSS surgery), 8 weeks after the intervention, and 3 and 12 months postoperatively. We will aim to recruit a convenient sample of 12 to 15 participants who completed the prehabilitation intervention to be interviewed at each time point (four interviews per participant). 73 The longitudinal qualitative study will assess the barriers and facilitators that influence engagement in prehabilitation from the patient perspective, as well as the changes in pain and health that occur over time and how these are related to the program and personal (e.g., sex/ gender, age, comorbid health, pain profile) or contextual factors (psychosocial, environmental, health systems). This longitudinal analysis will allow us to gain a deeper understanding of how and why changes in outcomes occur and the factors that influence these changes over time. 74

Data Collection
Data will be collected using one-on-one, in-depth semistructured interviews following an interview guide of open-ended questions based on relevant topics of interest (e.g., the effects of prehabilitation). The interview guide for this study was developed based on previous literature that has assessed implementation and dissemination of an intervention as well as the authors' prior understanding of LSS and clinical experience. Data collection and analysis for the qualitative study will be iterative, meaning the interview guide may be updated based on responses from each interview.
Qualitative interviews, approximately 60-90 minutes in length, will be scheduled at a time that is convenient to study participants and health care providers. Interviews will be conducted using the clouded-based service Zoom and audio-recorded and transcribed. Interested participants will be given a study information sheet by the interviewer prior to the interview. Verbal consent for participation in the study and permission for the audio recording will be conducted by the interviewer at the start of the interview.

Interviewer Experience
Qualitative interviews will be conducted by N.B., who is a chiropractor with 3 years of clinical experience and a PhD candidate in health sciences. N.B. has previous experience in conducting qualitative interviews and has undergone training in qualitative research methods.

Rigor and Trustworthiness
Several well-established techniques to ensure methodological rigor and trustworthiness for interpretive description will be used, including member checking (participants' comments on any developed themes), verification (researchers converge on recognizing "identical patterns" in the data), referential adequacy (providing enough quotes to ensure the findings fit the data), maintaining an audit trail (records of decisions made), and maintaining a reflexive journal (to help the interviewers identify how their experience may influence the study results). 73,75 Data Analysis

Quantitative
All quantitative analyses will be conducted using STATA BE 17. 76 Descriptive statistics will be used to report feasibility outcomes including recruitment rate, patient adherence to the program and attrition rates, acceptability of program content, and acceptability of study procedures and completion of study questionnaires.
(1) Recruitment Rate: We will proceed with the larger trial if we are able to recruit 60 participants within 12 months and if 50% of eligible participants consent to participate. (2) Adherence: Adherence to the exercise program will be considered adequate if 80% of all participants attend all four exercise sessions and 60% report exercise at least three times per week. (3) Attrition Rate: Follow-up will be considered adequate if 90% of participants are retained at the end of the intervention and 85% at 3 and 12 months of follow-up. We will also use the same cutoffs to measure data completion as a metric of attrition bias. (4) Content Acceptability: Content acceptability will be assessed using a VAS, where acceptability will be considered adequate if 60% of participants found the treatment useful and helpful with a score of 7/10. (5) Study Acceptability: Similarly, if 60% of participants found the treatment delivery acceptable and reported being likely to use this treatment again and recommend it to others with a VAS score of 7/ 10, the format will be considered acceptable. (6) Burden of the Questionnaire: We will assess participant burden of completing the questionnaires if more than 60% of participants scored >3/10 on the VAS scale indicating significant burden.
If any of the feasibility and acceptability criteria fall below the aforementioned thresholds, minimal or significant amendments to the study protocol will be required.
Additionally, we will identify trends in effectiveness using the patient-reported outcomes. According to the Sex and Gender Equity in Research guidelines, research findings should be separated by sex and/or gender, and an analysis of sex and/or gender differences/similarities should be described. 77 Given that this is a pilot study, we will assess trends in study outcomes based on sex and gender differences.

Qualitative
Audio transcripts obtained from Zoom will be reviewed for accuracy by a member of the research team. Interview transcripts will then be uploaded to the qualitative software Dedoose 78 to store and manage the data. Given the iterative process of data collection and analysis, each step will serve to inform the other. We will use thematic analysis to develop, understand, and examine patterns that are directed by the data. 72,79 Interview notes will be taken following each interview to capture salient points about the process and content. Analysis will continue with line-by-line readings of each transcript. Within each interview, meaningful sections of text will be given a conceptual code. Once codes are saturated, two members of the research team will develop overarching themes and subthemes based on reoccurring concepts. Themes will be compared within each participant, at each time point, and then will be compared between participants across all time points. The themes will be discussed and reviewed by all research members to ensure a holistic understanding of the findings from the lens of a surgeon, chiropractor, physiotherapist, and health researchers, and all feedback will be integrated into the study findings.

Discussion
The proposed prehabilitation study aims to evaluate the feasibility of evaluating an eHealth intervention to improve outcomes and understand the trajectory of recovery following SLSS surgery. The elevated levels of postoperative pain in this patient group and associated high levels of opioid use (i.e., 30%-60% of patients) are of concern, especially considering the older population. A patient-centered prehabilation program will shed light on the important and current public health problem of chronic pain in older adults and will address mandates of healthy aging particularly related to improving mobility and function.
The longitudinal qualitative component will allow us to assess trajectories of recovery over time as well as understand implementation-related factors. Given the complexity of the intervention, personal and contextual factors may impact the outcome of the intervention (e.g., adherence to exercise). We will be able to assess the barriers and facilitators that influence engagement in prehabilitation, as well as the changes in pain and health occurring over time and how these are related to the program and personal (e.g., sex and gender, age, comorbid health, pain profile) or contextual factors (psychosocial, environmental, health systems). This novel methodology will allow us to gain a deeper understanding of how and why changes in outcomes occur. 74,80 The qualitative component will help to develop a more comprehensive intervention that addresses long-term outcomes in patients postoperatively.
The potential challenge to the successful completion of this study is related to participant recruitment and adherence to the intervention protocol. The study is a longitudinal design, which may lead to increased dropouts that may affect the research outcomes. However, given that the study will be conducted primarily online, this may improve adherence and decrease overall dropouts. Further, the virtual nature of the intervention and data collection procedures may impose technological challenges to the older adult population that is the target in this study. We will ensure proper communication and time spent with participants to address any challenges with technology and access to resources.

Conclusion
The proposed study aims to evaluate a prehabilation program for individuals undergoing surgery for SLSS using best available evidence. This study will address chronic pain and disability in older adults with SLSS and will address mandates of healthy aging particularly related to improving mobility and function. The results of this study will be used to inform a larger, fully powered, RCT.

Ethics Approval and Consent to Participate
This application has been reviewed by the Hamilton Ethics Research Board at University of Alberta (Project #RES0052621) and the Hamilton Integrated Research Ethics Board (#13167).

Competing Interests
Nora Bakaa received funding from the Michael DeGroote Institute for Pain Research and Care (IPRC), the Canadian Institute of Health Research (CIHR) Doctoral Award, and the Canadian Chiropractic Research Foundation. Douglas P. Gross is an Editor-in-Chief of the Journal of Occupational Rehabilitation. He is chief investigator or co-investigator on multiple previous and current research grants from government research agencies in Canada (e.g., CIHR Alberta Innovates, Alberta Labour and Immigration) and the Netherlands (e.g., TechForFuture Centre of Expertise HTSM Oost). His research has also received funding from philanthropy and quasigovernmental agencies (e.g., Alberta Spine Foundation, Workers' Compensation Board of Alberta, Workers' Compensation Board of Manitoba, WorkSafeBC) and charities linked to professional body membership (e.g., Physiotherapy Foundation of Canada, Canadian Occupational Therapy Foundation). Additionally, he has received research grants from industry (Medtronic). His travel expenses have been covered when he has been an invited speaker at conferences and he has received honoraria for talks and reviewing grants and theses (no honoraria or travel expenses from pharmaceutical or device companies). Lisa Carlesso reports funding from the McMaster Institute for Research on Aging (MIRA), IPRC, Alberta Spine Foundation, the Arthritis Society STARS grant, as well as honoraria from EPG Health and the Canadian Orthopaedic Foundation. She also serves on the editorial board of the Pain Medicine Journal. Joy MacDermid's research is funded by CIHR. She receives royalties from Slack Inc. for co-editing a textbook and honoraria from Elsevier for serving as Editorin-Chief of the Journal of Hand Therapy. Maxi Miciak is an Associate Editor with the journal Physiotherapy Canada. She has worked as a research impact consultant for charities and nonprofit organizations in Canada (e.g., Multiple Sclerosis Society of Canada, Canadian Health Services and Policy Research Alliance, Alberta Strategy for Patient Oriented Research SUPPORT Unit, Alberta Bone and Joint Health Strategic Clinical Network). She is co-investigator on previous and current research grants from the Canadian Institutes for Health Research, a government research agency in Canada. Her research has also received funding from philanthropy and quasi-governmental agencies (e.g., Alberta Spine Foundation, Canadian MSK Rehab Research Network, WorkSafeBC, Kule Institute for Advanced Study). Additionally, she has received travel expenses and/or honoria as an invited speaker (e.g., Institute of Musculoskeletal Health and Arthritis, Canadian Institutes of Health Research, Physio Austria, Münster University of Applied Sciences). Luciana Macedo is an associate editor for BMC Musculoskeletal Disorders. She has grants from CIHR, the Canadian Musculoskeletal Rehab Network, MIRA, and the Chronic Pain Centre for Excellence for Canadian Veterans. Kenneth Thomas, Florence Slomp, Alison Rushton, Rob Smeets, Raja Rampersaud, Andrew Nataraj, Brian Drew, Pahuta Markian, Daipayan Guha, and Aleks Cenic report no conflicts of interest.

Disclosure Statement
No potential conflict of interest was reported by the authors.

Funding
This study is funded by the Alberta Spine Foundation. NB was also supported by the McMaster Michael DeGroote IPRC and the CHIR Doctoral Award. The authors also received an inkind donation from Physitrack for the use of the platform in this study.