Patients with severe low back pain exhibit a low level of physical activity before lumbar fusion surgery: a cross-sectional study

Low back pain (LBP) causes more disability than any other condition, and the years lived with disability due to LBP lead to huge costs for society [1]. The number of patients who undergo elective spinal surgery for lumbar degenerative conditions is increasing worldwide [2]. Lumbar degenerative disease, including disc herniation, spinal stenosis and chronic low back pain due to degenerative disc disease, constitutes the major reason for elective lumbar spine surgery [3]. Despite increasingly better outcomes after surgery over the past years, 40% of patients still report dissatisfaction and experience problems with their function 1 year after spinal fusion surgery [4]. Patients with higher levels of disability before lumbar spine surgery are at a greater risk of poor surgical outcome [2, 5]. Moreover, self-reported poor health at the time of surgery has a negative impact on its outcome [2].

Physical activity has well-documented positive effects on health, it reduces premature mortality and should be recommended to all people regardless of condition [6‐8]. People with LBP are at a higher risk of poor health (higher body mass index, higher blood pressure and a lower level of physical activity) due to this condition [9, 10]. In a recently published call for action on LBP, a stronger health focus was advocated [11]. The authors recommend that all actions in relation to LBP should be in synergy with the World Health Organization’s (WHO) action plans to prevent and control non-communicable diseases, such as having people reach the recommended level of physical activity. WHO recommends 150 min of at least moderate-intensity physical activity per week, performed in bouts of at least 10-min [12], equivalent to 7500 steps per day [13]. A prognostic longitudinal study, on patients seeking care for chronic LBP, showed that the group engaged in a higher activity level at baseline had less pain and disability at 12 months follow-up than the sedentary group [14]_. Moreover, a meta-analysis concluded that patients with chronic LBP who also have high levels of disability are most likely to have a low physical activity level [15]. Patients with severe LBP waiting for lumbar fusion surgery are assumed to be physically inactive and deconditioned, and their physical activity status before surgery can be used as an indicator of health status, but there is a lack of data on the level of physical activity before surgery measured objectively.

There are some studies available that have studied physical activity in relation to lumbar spine surgery [16‐20]. To our knowledge four studies have assessed the preoperative physical activity level [16, 18, 19, 21], in various lumbar degenerative conditions. None of these has investigated physical activity specifically for patients with degenerative disc disease. Since these patients differ from patients with spinal stenosis in that they are on average younger and have less leg pain [3], we hypothesised that the physical activity pattern would differ. Moreover, all but Norden et al. used self-reported data [18, 19, 21], which are considered less valid than those collected by objective measures such as an accelerometer [22]. We will therefore use accelerometers, considered to be one of the most valid measure, to accurately estimate levels of physical activity in daily life.

Various factors explain a low level of physical activity; the strongest correlates being age, sex, poor health status, low self-efficacy, and low motivation [23]. Moreover, pain itself is a barrier to being physically active. Factors included in the fear-avoidance model (e.g. catastrophizing, fear of movement and poor self-efficacy) can also be barriers to being physically active [24, 25]. Fear-avoidance beliefs have been found to be significant predictors of pain and functional outcomes for up to 2 years after lumbar spine surgery [26]. Until now, no studies have investigated the association between physical activity and fear-avoidance factors for patients with severe LBP scheduled for lumbar fusion surgery.

This cross-sectional observational study was conducted and reported according to the Strengthening the Report of Observational Studies in Epidemiology (STROBE Statement) [27]. The data in this study are baseline data collected in a randomised controlled trial before any treatment [28].

The study comprised 63 women and 55 men with a mean age of 46 (SD = 8) years. Forty-one (35%) patients were on sick leave, and 11 (9%) patients had had previous lumbar spine surgery (Table 1).

Eighty-seven (74%) patients had suffered from back pain for more than 2 years. On average, the patients had a moderate disability (ODI), moderate level of back pain (VAS), high fear of movement (TSK), moderate pain catastrophizing thoughts (PCS), and reduced health-related quality of life (EQ5D index) (Table 2).

This study demonstrates that the majority of the patients, scheduled for lumbar fusion surgery, were insufficiently active, according to the variable of “physical activity intensity” (10-min bouts). Further, more than half of the patients did not reach the level of a physically-active lifestyle measured by the variable “steps per day”. Moreover, their steps per day was negatively associated with both fear of movement and disability.

These are some of the first results in the world, based on objective measures, investigating the physical activity status in patients with severe LBP scheduled for lumbar fusion surgery. As many as 83% did not reach the WHO recommendations of physical activity for health. As compared to a “healthy population” in Sweden [43] and Germany [44] this suggests a large proportion of the patients in our study has therefore an increased risk of developing additional disease and poor health [7]. This suggests that a majority of the patients in our study do not reap the health benefits of being sufficiently physically active and are therefore at risk of developing additional disease and poor health [7]. Similar findings have been found by Mobbs et al., [16] and Norden et al., [21]. Mobbs et al. studied a mixed group of patients with degenerative lumbar disorders and found that the mean value for the variable “steps per day” (5255 steps) was below the threshold for a physically active lifestyle [16]. They also used an accelerometer but only presented the variable as “steps per day”. Norden et al. showed that only 4% of their patients with spinal stenosis met the physical activity recommendations before decompression surgery [21]. Moreover, a recently published systematic review and meta-analysis by Koenders et al., [45], concluded that “research should provide more information regarding the clinical care pathway, psychosocial and physical conditions of the patients undergoing first time lumbar fusion surgery, and without this information, it remains impossible to improve lumbar fusion surgery management”. We would argue that the new knowledge presented in our manuscript will help clinicians in structuring the rehabilitation program including the prehabilitation phase. Our results indicate that the physical activity level was low for a high proportion of our study group. If these patients remain inactive after surgery, maintaining their preoperative low activity levels and sedentary lifestyles, they will increase their risk of developing additional disease. By accurately measuring the physical activity level before surgery, the patient’s physical activity behaviour might be addressed preoperatively, increasing the chance of a healthier outcome of surgery.

There is a dose-response relationship between physical activity and health, i.e., the more physical activity, the better the health improvements. The largest health effect is gained by encouraging the most physically-inactive persons to become more physically active [46]. A high proportion of our study population was physically active at a lower level, and 19 patients (16%) were identified as having a sedentary life style, using the variable “steps per day”. The largest health effects are potentially to be gained by encouraging this subgroup to be more physically active. There was a large variation in physical activity levels in our patient group. Twenty patients (17%) were highly physically active and reached the WHO recommendations, and nearly half of the study group (46%) reached the physically-active lifestyle, as measured by the variable “steps per day”. “Steps per day” is not part of the WHO recommendations but offers a new way of translating the WHO guidelines in to a measurement that is easy to understand and communicate to the patient [13]. This measurement of physical activity is a valuable tool when designing personalised physical activity goals for patients that need or want to improve their physical activity levels.

The results in the present study showed a negative association between the amount of steps per day and both fear of movement and disability. This means that, if the levels of fear of movement and disability decrease, the number of steps per day might increase. Similar results were seen in a study by Donnarumma et al. of patients awaiting lumbar decompression and fusion surgery [47]. Their results demonstrated a significant correlation between self-reported low levels of physical activity and higher levels of disability, as well as higher levels of fear of movement [47]. Physical activity is, however, a complex behaviour and increasing physical activity is part of a behaviour change process. We also found that our study group presented with fear of movement (kinesiophobia), catastrophizing thoughts and reduced self-efficacy for exercise. Factors such as fear of movement and low self-efficacy are identified as barriers to physical activity. It has been suggested elsewhere that targeting fear of movement before surgery will increase the likelihood of a better functional outcome [48]. Since the largest health benefits are potentially gained by people with a less active or sedentary lifestyle, it is important to identify such patients, as well as those with fear-avoidance behaviours in the prehabilitation phase. A person-centred approach in the prehabilitation phase could help guide clinicians in structuring a personalised prehabilitation plan, focusing on each patient’s needs and preferences. Such an intervention program has been set up by the authors [28], and its results are under investigation.

The current study shows that a high proportion of the patients do not match the WHO health recommendations on physical activity and are therefore at risk of poor health due to insufficient physical activity. Moreover, we also found a negative association between both fear of movement and disability, and the amount of steps per day. Actions need to be taken to motivate patients to be more physically active before surgery. To successfully address low physical activity in patients with severe LBP awaiting lumbar fusion surgery, a better understanding of the reasons behind this low level may be important as an aid to increase the chance of a healthier outcome following surgery. There is a need for interventions aiming at increasing physical activity and to reduce barriers to physical activity in the prehabilitation phase for this patient group.