Changes in flexion-relaxation phenomenon and lumbo-pelvic kinematics following lumbar disc replacement surgery

Julie O’Shaughnessy,Martin Descarreaux,Jean-François Roy

doi:10.1186/1743-0003-10-72

Abstract

BackgroundA single group prospective study. Disc prostheses are believed to contribute to the restoration of the segmental movement and the preservation of the adjacent segments. The study’s main objective was to determine if changes in neuromuscular patterns assessed using the flexion-relaxation phenomenon (FRP) can be observed following disc replacement surgery.MethodsFifteen subjects participated in this study; they were evaluated before and after lumbar disc replacement surgery. Both assessments included ten repetitions of a trunk flexion and extension movement (with and without a load), where the surface electromyography (EMG) and kinematic data were recorded.ResultsFollowing the disc replacement procedure (17.3 weeks ± 8.4), participants reported a significant reduction in their ODI and FABQ - physical activity scores. Increases in pelvic flexion as well as in erector spinae (ES) muscle activity at L5 in the flexion phase were observed. Following the disc replacement surgery, ES activity at L2 decreased during the quiet standing position.ConclusionThe results of this study suggest that although improvements in disability scores and fear-avoidance related to physical activities scores were noted after a disc replacement surgery, the lumbar ROM was not modified. Nevertheless, a significant increase in the hip ROM during the flexion-extension task as well as an increase in ES muscle activity in flexion was observed following surgery. The VAS, FABQ I and ODQ scores were positively correlated with change in the muscular activities during the FRP.

Highlights

The participants included in the present study were all scheduled for elective disc replacement surgery for chronic low back pain (CLBP) and were all recruited from the same orthopaedic clinic
Clinical outcomes All participants had a history of CLBP for more than 24 months
The 1.4 points decrease observed for the Visual Analogue Pain Scale (VAS) scores indicates clinical improvement (clinically important difference (CID) of 1.20 to 1.74 point) but did not reach statistical difference [44,45]

Summary

Introduction

Disc replacement surgery was developed as an alternative to fusion’s long term complications such as the increase of mechanical stress and load on the adjacent segments. These increased loads can lead to postsurgical vertebral instability, early disc degeneration and pain. Symptomatic adjacent segment disease (ASD) is found in 5.2 to 18.5% of the patients who present with CLBP after a fusion and can lead to a second surgical intervention, often with limited results [14,15]. In a systematic literature review on symptomatic ASD (only four articles reported), Harrop et al.[16] estimated that this type of complication was only present in 1% of the patients at 8.7 to 13.2 years following arthroplasty. Disc replacement might preserve or increase the segmental range of motion (ROM), keeping the physiologic lumbar spinal kinematic properties [10,11,18,19,20]

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Discussion

Conclusion