INTRODUCTION: The treatment of low back pain (LBP) with de novo degenerative lumbar scoliosis (DLS) is the subject of much debate. We speculate that bone marrow edema (BME) frequently found in the endplates at the concave side of scoliosis on MRI is strongly associated with LBP. We developed a targeting operative therapy; percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI) for LBP associated with DLS in the elderly. The aim of this study is to report long-term outcomes of PIPI as a treatment for LBP in the elderly DLS patients.
METHODS: We included de novo DLS patients aged 65 years and over who had LBP (VAS >50) at least 6 months with intervertebral vacuum phenomenon and BME defined on MRI. 80 patients who underwent PIPI could be followed more than 2 years. The outcomes were evaluated using Visual analog scale (VAS) of LBP, and the Oswestry Disability Index (ODI). As the objective changes, we measured BME score on MRI. Mean follow-up period was 54.6±21.0 months.
RESULTS: The mean VAS and ODI scores were 81.5±14.9 and 52.0±15.3 at the baseline. These scores were significantly improved at 1 month after PIPI (29.9±21.6, 29.3±18.1). These scores were 26.7±24.9, 32.5±17.2 at 2 years after PIPI and 29.7±18.6, 32.9±14.0 at final follow-up. After PIPI, mean BME score was significantly decreased (P<0.001), and correlated with the VAS and the ODI scores (VAS: r=0.502, P<0.001, ODI: r=0.372, P<0.001). During final follow-up, LBP was recurred in 28 patients (mean 32.3 months after PIPI) due to recurrence of BME in the same level of PIPI (10 patients), adjacent level disorder (10 patients), and other level disorders (8 patients). The recurrences of BME were significantly appeared at lateral slip levels (p<0.001). For the salvage surgery, we added PIPI for 18 patients and PIPI and posterior fusion for 1 patient, and the VAS scores were improved from 80.0±12.4 to 34.3±17.8.
DISCUSSION: PIPI achieved a positive effect in terms of LBP relief. For the salvage surgery, a secondary PIPI after the initial PIPI was also effective for the recurrence of LBP. PIPI can be recommended as an effective and repeatable treatment for elderly DLS patients.