Step activity monitoring in lumbar stenosis patients undergoing decompressive surgery

Abstract

Symptomatic degenerative central lumbar spinal stenosis (LSS) is a frequent indication for decompressive spinal surgery, to reduce spinal claudication. No data are as yet available on the effect of surgery on the level of activity measured with objective long-term monitoring. The aim of this prospective, controlled study was to objectively quantify the level of activity in central LSS patients before and after surgery, using a continuous measurement device. The objective data were correlated with subjective clinical results and the radiographic degree of stenosis. Forty-seven patients with central LSS and typical spinal claudication scheduled for surgery were included. The level of activity (number of gait cycles) was quantified for 7 consecutive days using the StepWatch Activity Monitor (SAM). Visual analogue scales (VAS) for back and leg pain, Oswestry disability index and RolandMorris score were used to assess the patients' clinical status. The patients were investigated before surgery and 3 and 12 months after surgery. In addition, the radiographic extent of central LSS was measured digitally on preoperative magnetic resonance imaging or computed tomography. The following results were found preoperatively: 3,578 gait cycles/day, VAS for back pain 5.7 and for leg pain 6.5. Three months after surgery, the patients showed improvement: 4,145 gait cycles/day, VAS for back pain 4.0 and for leg pain 3.0. Twelve months after surgery, the improvement continued: 4,335 gait cycles/day, VAS for back pain 4.1 and for leg pain 3.3. The clinical results and SAM results showed significant improvement when preoperative data were compared with data 3 and 12 months after surgery. The results 12 months after surgery did not differ significantly from those 3 months after surgery. The level of activity correlated significantly with the degree of leg pain. The mean cross-sectional area of the spinal canal at the central LSS was 94 mm 2 . The radiographic results did not correlate either with objective SAM results or with clinical outcome parameters. In conclusion, this study is the first to present objective data on continuous activity monitoring/measurements in patients with central LSS. The SAM could be an adequate tool for performing these measurements in spine patients. Except for leg pain, the objective SAM results did not correlate with the clinical results or with the radiographic extent of central LSS.

Prospective evaluation of physical activity in patients with idiopathic scoliosis or kyphosis receiving brace treatment

“…Previous studies have documented the validity and reliability of this monitor in children and adolescents [21,23]. The SAM was also used in a previous study to evaluate step activity in lumbar spine patients [36], justifying its application in spine patients. It carries out measurements without providing feedback to the patient, thus minimizing test bias.…”

Objective Measurement of Free-Living Physical Activity (Performance) in Lumbar Spinal Stenosis: Are Physical Activity Guidelines Being Met?

“…It is recognized clinically that neurogenic claudication limits consecutive walking in people with LSS [56]. In studies of LSS, individuals walk until forced to stop because of symptoms, and almost never sustain physical activity over a long period of time [2,3,17,56]. It follows that recommending an increase in physical activity throughout the day, in whatever way possible (shorter bouts), may be more realistic than requiring an activity to be over an extended period of time, like 10 minutes.…”

“…Lumbar spinal stenosis (LSS) is a painful, debilitating condition [1][2][3][4][5][6][7][8] with an estimated prevalence of 9% in the general population, and up to 47% in people over age 60 [9]. Lumbar spinal stenosis is the most common reason for spine surgery in patients over 65 [10], with a current estimated 2-year cost of $4 billion in the United States [11,12].…”

“…Lumbar spinal stenosis is characterized by neurogenic claudication and mobility limitations [1][2][3]17,18]. Yet, despite the fact that neurogenic claudication is the hallmark of LSS, the effects of symptoms on free-living physical activity (performance) are not well understood.…”

“…Fortunately, recent advances in wearable technology have provided us with the tools to objectively measure free-living physical activity (performance) in people with LSS. Using accelerometers, we are beginning to understand more about performance in this population [1][2][3]20,21]. Some preliminary work with pedometers demonstrated that people with LSS take an average of around 4,000 steps/day [17], which is considered sedentary [22].…”