Abstract
The “Wallis” implant is indicated to stabilize symptomatic degenerative lumbar spine segments, relieving low back pain related to instability and thus delaying the need for irreversible, more invasive surgical management. The purpose of this study was to provide the first objective clinical evaluation of the “Wallis” lumbar dynamic stabilisation system.
An independent prospective observational study was carried out utlising SF-36, Oswestry Disability Index (ODI) and visual analogue pain scores (VAS). Surgical pathologies in which this technique was used, the intra-operative and post-operative complications and length of post-op stay were recorded. 102 patients underwent Wallis insertion between June 2007- May 2009, Median age 51.5 (range 28-108). 94% of patients completed questionnaires and were followed up at 3, 6 and 12 month time points. ODI scores decreased from pre-op 39 to 27 at twelve months (p<.0016). VAS back pain scores decreased 59 to 36 (p<0.0001). Leg scores decreased 50 to 39 (p<0.0002). SF 36 scores improved significantly, physical functioning 46 to 59, physical health 30 to 54 and social functioning 47 to 68. 50% of patients believed their health to be better 12 months post-op. Pre-operatively 28% of patients were employed and working with 26% off work due to back problems. This rate increased steadily with 42% employed at 12 months. Two implants were removed, one due to non-benefit with subsequent arthrodesis and one due to infection. One superficial wound infection occurred.
The Wallis dynamic stabilization system provides a superficial and easily reversible surgical procedure with a lower complication rate than conventional athrodesis. Used in patients with painful degenerative lumbar conditions their quality of life objectively approached values of the age- and gender-matched general population.
