The boot camp program for lumbar spinal stenosis: a protocol for a randomized controlled trial

Lumbar spinal stenosis (LSS) refers to an anatomical narrowing of the central and/or lateral spinal canals [1]. It is usually caused by age related degenerative changes in the spine including intervertebral disc thinning, facet joint thickening and in-folding of the ligamentum flavum [2]. These changes contribute to a decrease in cross-sectional area of the spinal canal that can lead to compression and diminished blood flow to the spinal nerves [3, 4]. The clinical syndrome caused by LSS is known as neurogenic claudication. This syndrome is characterized by bilateral or unilateral buttock, lower extremity pain, heaviness, numbness, tingling or weakness, precipitated by walking and standing and [5] relieved by sitting and bending forward [2, 6]. Neurogenic claudication due to LSS is a leading cause of pain, disability and loss of independence in people over the age of 65 [7]. Limited walking ability is the dominant functional impairment caused by LSS [2]. Those afflicted have greater walking limitations than individuals with knee or hip osteoarthritis [8] and greater functional limitations than those with congestive heart failure, chronic obstructive lung disease or systemic lupus erythematosus [7]. Inability to walk among individuals with LSS leads to a sedentary lifestyle and a progressive decline in health status [9, 10]. Furthermore, symptomatic LSS is also associated with increased levels of depression; anxiety and hopelessness that can further perpetuate disability [11–14].

The prevalence and economic burden of LSS is growing exponentially due to the aging population. In Japan where 25 % of the population is over the age of 65, about 12 million people suffer from symptomatic LSS [15]. A similar epidemic is expected in the US by the year 2030 when an estimated 73 million people will be over the age of 65 [16] of which 30 % are projected to have symptomatic LSS [17]. LSS is the most common reason for spine surgery in individuals over the age of 65 [18], however only very few patients receive surgery [19]. The vast majority of individuals with LSS receive non-surgical care. However, what constitutes effective non-surgical care is unknown [20–23].

We have designed and implemented a training program for LSS known as the Boot Camp Program for LSS [24]. This program aims to address the multi-faceted aspects of LSS using a multi-modal non-surgical approach with a focus on self-management and the goals of improved walking ability, overall functional status and quality of life. The program considers the dynamic nature of LSS where symptoms change relative to posture. Reduction of the lumbar lordosis while standing, walking and sitting reduces epidural pressure and improves blood flows to spinal nerves [3, 11]. Enabling patients to introduce inter-segmental lumbar spine flexion (reducing the lumbar lordosis) using anterior pelvic tilt may reduce symptoms and improve walking ability [25–27]. Individuals with LSS tend to be deconditioned due to inability to walk and consequential sedentary lifestyle and may not have the necessary core strength and lumbar flexibility to accomplish this body realignment. They can also have reduced lower extremity strength due to combined nerve root compression and disuse. Specific flexibility, aerobic and core and lower extremity strengthening exercises, manual therapy and postural instruction may overcome these deficiencies.

The program also considers potential psychosocial consequences of LSS and incorporates a cognitive behavioral approach [28, 29]. This approach aims to improve coping and problem solving, build self-efficacy, provide feedback and develop realistic treatment and functional goals. Since LSS is a chronic and often-progressive condition [30] the program emphasizes incorporating learned physical and psychosocial self-management strategies for life. Patients receive an instructional workbook and video as part of the training program. The workbook and video provide education on self-management strategies and instruction on how to perform all the specific exercises and body realignment techniques. The workbook incorporates a schedule outlining the intensity and frequency of each exercise with goals tailored to each patient. The training program also includes a pedometer that provides weekly feedback for both patients and practitioners on walking ability.

In a previous retrospective study we evaluated 49 consecutive patients who completed the Boot Camp Program and assessed the difference in self-report outcomes selected a priori [24]. Outcome measures included the Oswestry Low Back Pain Disability Index, the walking score of the Oswestry Low Back Pain Disability Index, the three subscales of the Zurich Swiss Spinal Questionnaire, and the Numeric Rating Scale for leg and back pain. Following the 6-week intervention there were both statistically and clinically important improvements in all outcomes from baseline. This was a before and after study without a control group and therefore provided low quality preliminary evidence on the effectiveness of the program.

The purpose of this study is to assess the effectiveness of the Boot Camp Program in improving outcomes using a randomized controlled trial (RCT) design. Our main objective is to compare the effectiveness of a comprehensive 6-week self-management training program that includes a patient instructional workbook, video and pedometer to a single training session with provision of a patient workbook, video and pedometer. We hypothesize that the self-management training program will be more effective in improving walking capacity and functional outcomes than a single training session.

We selected a pragmatic RCT design for our study to reflect a more real world clinical setting. LSS is a varied and multi-faceted condition and in practice, the approach is to tailor care to the patient’s individual needs and tolerances. Participants randomized to Group 1 will receive the standard approach provided at the Spinal Stenosis Clinic at Mount Sinai Hospital; however tailoring will be required with respect to the intensity and type of exercise and manual therapy techniques used, not unlike usual practice. We selected a RCT design because it is the study design of choice when comparing the effectiveness of interventions.

We considered the SPWT to be the appropriate primary outcome measure to address our primary aim. The SPWT is the current gold standard for measuring objective walking capacity in LSS as it assesses walking ability in a real life setting [43]. We also included the functional scale of the ZCQ which is a self-report measure of walking ability that is highly correlated (r = 0.80) to the SPWT [31]. The SPWT is logistically more challenging to perform because of the need of a large walking area and added personnel, time and expense of conducting the test, and added time, expense and inconvenience for participants travelling to the study site for follow-ups. This may result in a higher dropout rate for follow-up assessments. To mitigate this possibility of non-compliance to follow-up SPWTs we included the self-report functional scale of the ZCQ that can easily be assessed by phone. Moreover, we can compare our findings to other studies using this self-report outcome measure.

At our centre we have two long and wide hallways connected by two shorter hallways forming a large rectangular area (140 m long) where participants easily can perform the SPWT.

However, the SPWT has a ceiling effect in that the test measures distance traveled for a maximum of a 30-min period. For this reason we will only include participants who are more severely impaired and cannot complete the SPWT during the baseline assessment.

We have included a 1-month booster session following the 6-week training program. This emulates our current practice protocol at our Spinal Stenosis Clinic at Mount Sinai Hospital. The rationale being that LSS is a chronic condition and patients may benefit from periodic monitoring of their self-management skills and abilities. Periodic reassurance and positive reinforcement may also be of benefit especially among patients with underlying psychosocial barriers such as poor coping skills that accentuate functional limitations. Periodic monitoring and coaching may help to improve longer-term outcomes.

A leading cause of failure of RCTs is the lack of enrollment of sufficient number of participants into the study. We have enlisted a large referral source for potential participants. LSS is a very common condition seen by neurosurgeons and orthopedic spine surgeons, rheumatologists, physiatrists, family physicians and chiropractors. If our enrollment is deemed slow, we will expand our referral source to the University of Toronto vascular surgeons who also see a large number of patients with neurogenic claudication caused by LSS. We will also advertise in local newspapers and seniors publications. In addition, we will distribute pamphlets to be placed in-patient waiting areas at participating hospital clinics and in community clinics. Compliance to follow-ups may be problematic and we plan to provide incentives in the form of covering transportation costs up to $25 per day.

We anticipate that assessor blinding (to assigned intervention) during follow-up assessments will be challenging. We will implement strict rules preventing the communication, regarding participant allocation among participants, the research coordinator and blinded assessors.

Study design limitations include the lack of blinding of both practitioners and patients and this can introduce bias. The multi-modal and pragmatic nature of the design prohibits the determination of the component(s) of the intervention that may be responsible for potential improvements. There is potential for participants to receive other interventions during the intervention and between follow-up periods, which may impact the results. We will compare co-interventions receive between group and comment on the potential impact they may have on the results.

There is a high risk of falls in the LSS population and we need to ensure safety of participants while performing the SPWT. We will train assessors accompanying participants during the SPWT and practice procedures to reduce the risk of falls during the SPWT.

Participants randomized to the single instructional session may not follow the provided instructions, or may perform the exercises incorrectly leading to potential for injury. We will incorporate a safety monitoring protocol and provide participants the opportunity to contact us in an effort to reduce the risk of harm to participants randomized to this intervention.

LSS is a chronic arthritic condition whose prevalence, personal and economic burden is growing exponentially due to the aging population. The vast majority of individuals with LSS receive non-surgical care however, what constitutes effective non-surgical care is unknown. A multi-modal approach with a focus on self-management strategies as outlined in this proposal may be a practical and effective means to improve walking ability, functional status and quality of life in this population.