Introduction
Neurogenic claudication (NC), caused by lumbar spinal stenosis, causes symptoms of pain, numbness and/or weakness in the legs and results in difficulty walking. Surgery aims to improve symptoms and walking yet, for unknown reasons, most people do not increase their walking post-operatively. This means they are at risk of the negative consequences of inactivity. The aim of this study was to identify modifiable factors that could be targeted with rehabilitation and behaviour change strategies so that walking may be improved.
Methods
A prospective longitudinal study recruited adults (≥50 years, listed for surgery to treat NC). Walking capacity and performance was assessed pre-surgery and 12-weeks postoperatively using the six-minute walk distance (6MWD, m) and mean daily step count measured with an accelerometer for seven days (daily step count). A range of measures were collected pre- and 6 and 12 weeks post-operatively including potentially modifiable biopsychosocial variables, mapped to a behaviour change model (COM-B1), e.g. balance and falls, fear of movement, lower limb function, illness perceptions, self-regulation, social support. Analysis included descriptive, correlation and regression statistics.
Results
134 participants were recruited (51% male, mean age 70-years(±8.6)). 116 underwent surgery, 109(94%) provided follow-up data. Mean (standard deviation) pre and post-operative scores were 6MWD 237.5(±113.3)-297.5(±108.2), daily step count 4840.8(±2490.5)-5429.85(±3045.4), Oswestry Disability Index 43.0(±15.1)-27.1(±17.9)(all p<.05). Less than 50% achieved minimum clinically important difference in 6MWD and daily step count. Only 25% walked ≥7000steps/day.
The strongest correlation with post-operative walking was pre-operative walking for all walking measures (6MWD: r=0.774). Pre-operative history of falls (b:-.29; 95%CI-.44,-.13), fear of falling (b:-.55; 95%CI-.69,-.41), fear of movement(b:-.48; 95%CI-.63,-.33), lower limb function (b:.75; 95%CI.64,.86), social support (b:.2; 95%CI.12,.45), self-regulation of exercise (b:.26; 95%CI.09,.42), physical environment (b:.28; 95%CI.12,.45), grip strength (b:.23; 95%CI.05,.41), coherence (b:-.17; 95%CI-.33,-.01) and control of condition (b:.14; 95%CI.02,.31), were associated with pre-operatively walking capacity and performance (p<.05). Pre-operative history of fear of falling (b:-.14; 95%CI-.30,-.02), self-regulation of exercise (b:-.13; 95%CI-.27,-.01) and grip strength (b:-.29; 95%CI-.58,-.01) were associated with change in post-operatively walking capacity and performance (p<.05). At 6-weeks post-operative fear of falling (b:-.20; 95%CI-.36,-.04) and fear of movement (b:-.24; 95%CI-.41,-.06) were associated with less improvement in walking capacity and performance at 12-weeks post-operative(p=.01).
Discussion
Baseline walking capacity and performance explained a large proportion of the residualised change score in walking improvement. Potentially modifiable determinants of walking in adults with NC were: fear of falling and fear of movement, lower limb function, social support, self regulation of exercise, strength, coherence and control of condition.
The majority of people following surgery for NC continue to have limited walking and do not achieve physical activity recommendations. Rehabilitation is required to help people increase their walking to reduce the risks of inactivity. Prehabilitation should be considered to try to optimise pre-operative walking. Rehabilitation should include behavioural change techniques focussing on reducing fear of falls and fear of movement as well as training strategies.