Preoperative sport improves the outcome of lumbar disc surgery: a prospective monocentric cohort study

A lumbar disc herniation is considered a major source of low back pain and radiculopathy by mechanical compression of the corresponding lumbar nerve root. The annual costs in terms of lost productivity, medical expenses, and worker’s compensation benefits are significant. [1] A minority of patients affected require surgical treatment by lumbar sequestrectomy, especially in medical refractory pain or in the presence of neurological deficits. [2, 3]

A lumbar disc herniation prompting surgery may be an incisive event in a patient’s everyday life. The patient’s recovery and improvement of pain after lumbar spine surgery may be influenced by several factors. [4] It is known that a physically active lifestyle is crucial for a variety of health-related benefits. It has also been suggested that regular physical activity can lower pain perception and improve outcome after surgery. [5] In contrast, reduced exercise has been linked to various chronic health disorders particularly to musculoskeletal complaints. [6] Physical activity in the management of low back pain is therefore widely recommended. [7]

Nevertheless, the influence of regular physical activity prior to lumbar spine surgery on postoperative outcome has not yet been investigated in a prospective clinical trial. Thus, we hypothesized that patients who perform sports regularly before lumbar disc surgery might have less pain and disability thereafter. Therefore, the objective of this study was to prospectively assess the effect of baseline physical activity level on pain, satisfaction, and disability after lumbar disc surgery.

Fifty-two consecutive patients met the inclusion criteria and could be enrolled in the trial. By chance, they were divided symmetrically into patients with regular physical activity (group S; n = 26) and those without (group NS; n = 26). The loss to postoperative 6-month follow-up was 1.9% and to 12-month follow-up was 3.8%. A recurrent disc herniation occurred in six (23%) patients in group NS and in three (11.5%) patients in group S (p = 0.465). An accidental durotomy occurred in one patient in group NS. These patients were excluded from further statistical analysis, as these factors could have influenced the outcome data.

The preoperative demographic data is described in Table 1. The most common Pfirrmann grade was IV° in both groups and there was not statistically significant difference between groups. 80.7% of group NS and 46.1% of group S showed Modic changes in MRI (p = 0.006). There were no significant differences in total muscle size or fatty degeneration (p > 0.05). Study participants preferred sports with high dynamic and moderate intensity (see Fig. 1).

EQ-5D index, COMI, and ODI showed a remarkable increase in the quality of life, overall outcome, and disability 12 months after lumbar sequestrectomy in both groups (p < 0.005) (Table 2).

The overall ODI differed 6 months postoperatively: group NS 11.9 ± 11 vs. group S 5.0 ± 6 (p < 0.05). Differences were found particularly in pain intensity (group NS: 1.0 ± 0.8 vs. group S: 0.5 ± 0), lifting (group NS: 1.0 ± 0 vs. group S: 0.3 ± 0), walking (group NS: 0.2 ± 0 vs. group S: 0.0 ± 0), and standing (group NS: 0.8 ± 1 vs. group S: 0.3 ± 0) (p < 0.05). Group S showed a significantly higher quality of life 6 months postoperatively, group NS 0.93 ± 0 vs. group S 0.96 ± 0, respectively (p < 0.05). COMI also revealed differences between the two groups 6 and 12 months postoperatively (p < 0.05).

VAS for leg and back pain improved significantly in both groups after 12 months (p < 0.005). Leg and back pain on VAS was rated significantly lower in group S than in group NS 12 months postoperatively (p < 0.05, Fig. 2). Preoperative motor deficits improved significantly in both groups after 12-month follow-up (p ≤ 0.005). Seventy percent in the NS group and 62% in the S group took analgesics on a regular basis before surgery (Table 3). No permanent pain medication was used postoperatively.

The authors present the first prospective clinical trial investigating the influence of preoperative sports on the patient’s satisfaction and recovery after lumbar sequestrectomy. Disc surgery resulted in an overall significant improvement after 12-month follow-up, whereas patients doing preoperative sports on a regular basis showed a significantly better outcome. Leg and back pain 1 year after surgery was worse in the group of patients who did not perform preoperative regular sports. The differences found not only proved to be statistically significant, but also seem to be clinically relevant according to recent literature on the minimal clinical important difference. [16]

A lumbar disc herniation prompting surgery may be an incisive event in a patient’s everyday life. The patient’s recovery and improvement of pain after lumbar spine surgery may be influenced by various factors. [4]

The presence of depression might have a negative effect of the improvement after surgery. [17] Patients with mental disorders were excluded from our trial. Thus, BDI scores did not differ between the two investigated groups and this could be ruled out as a confounding factor. Furthermore, gender plays an important role in patients with radiculopathy caused by a lumbar disc herniation, as female gender might influence the patient’s pain perception in a negative way. The distribution of sexes was equal between our two study groups. Additionally, the surgical technique itself may be crucial for the patient’s outcome after surgery. Sequestrectomy as the standard surgical technique in our department and invariably used in this trial previously demonstrated superior results than lumbar discectomy. Lower recurrent back pain and superior satisfactory rates were observed in the short- as well as long-term follow-up. [3, 18]

Nevertheless, the influence of regular preoperative physical activity on postoperative outcome has not yet been investigated prospectively. Few studies could show that physiotherapy improves the patients’ reported outcome and healthcare consumption after surgery. [19] In general, there is evidence that a higher amount of physical activity is associated with less low back pain. [20] Endurance exercise for example, as preferred sports in our trial, is known to promote antinociceptive effects more likely on central processing rather than on peripheral pain. [21] It has to be kept in mind, however, that not only physical activity prior to surgery but as well thereafter may have an impact on surgical outcome. This can be within a rehabilitation program or by resuming preoperative sports. While postoperative rehabilitation did not differ between groups in our study, it is likely that preoperatively active patients resumed their activity postoperatively, which may be even more important for their respective outcome. Although sports on a regular basis seem to reduce pain perception, it does not decrease the risk to develop a lumbar disc herniation as the disc degeneration itself is multifaceted and traditionally attributed to age, mechanical loading, gender, trauma, and other factors impairing disc nutrition. [22, 23] Furthermore, a higher prevalence of structural abnormalities was reported in adolescent athletes compared to adolescent non-athletes, whereas an association to disc degeneration was not found. [24] Disc degeneration grades in our study population were equally distributed in the two investigated groups. On the contrary, Modic changes were less in the sports group. It could be speculated that regular physical activity may have a positive effect on disc and endplate nutrition resulting in less Modic changes in contrast to the mentioned negative effect of excessive exercise in adolescent athletes. The impact of Modic changes on postoperative clinical outcome, especially low back pain, however, is still a matter of debate, although an association with patient satisfaction has been reported. [25] These radiological differences between groups might explain some of the differences in clinical outcome.

In summary, regular exercise may positively influence regeneration of a disc degeneration early in the degenerative cascade by enabling a better disc nutrition. [26] It may be important that our patients were no professional athletes, as over-exercise may accelerate disc degeneration. [24]

Obviously, the treating surgeon cannot influence the patients’ baseline characteristics, namely preoperative physical activity and preoperative sports will not have an impact on surgical indications. Nevertheless, our results indicate that resumption or adoption of physical activity after disc surgery may be encouraged. Plus, the data support health promotion programs, which have gained popularity in the last decades to reduce health-related expenses by alleviating musculoskeletal pain. [27].

A recurrent lumbar disc herniation is the most prevalent cause for postoperative radicular pain. Rates quoted range from 3 to 19% with the higher rates usually in series with a longer follow-up. Multiple risk factors for recurrent disc herniations exist and are discussed controversially. Beneath young age, severe disc degeneration, traumatic events and gender seems to play a major role for the development of a recurrent disc herniation. [28] There was a trend towards higher reherniation rates in the NS group in our study. Large anular defects have been associated with higher reherniation rates [29] and technical nuances particularly concerning aggressiveness of disc removal also influence reherniation. [3, 18, 30] Our department’s standard operating procedure involves pure sequestrectomy in absence of a clear anular defect and limited discectomy in case of larger anular defects, so that there were no differences in surgical technique between groups. The sizes of the anular defects were not assessed in our study, but could have influenced the results. We postulate, however, that regular sports might even reduce the risk of recurrent disc herniations. Obviously, larger comparative studies are needed to confirm these findings.

Strengths of our study include the use of the validated, standardized comprehensive questionnaires like ODI, COMI or EQ-5D. Furthermore, we are able to present a homogenous study population, while we excluded individuals with major depression or chronic pain/neurological disorders. However, the small patient cohort is a limitation that might have introduced selection bias. The assessment of physical activity in our trial was based on self-reported values. This may have led to over-reporting of quality and quantity of physical activity. [31] Therefore, data would be more accurate when using activity measuring devices like an actigraph.

Our data suggests that preoperative regular physical activity is an important influencing factor on the overall satisfaction and disability after lumbar disc surgery. It potentially has the capacity to reduce not only low back pain, but also leg pain after sequestrectomy. Therefore and because of many more health advantages humans may gain, physical activity should be an essential element in everyday’s life. The importance of sports may have been underestimated for surgical outcomes in general.