The Effect of Early Limited Activity after Bipedicular Percutaneous Vertebroplasty to Treat Acute Painful Osteoporotic Vertebral Compression Fractures

Background: Although percutaneous vertebroplasty (PVP) can effectively relieve the pain for patients with acute osteoporotic vertebral compression fractures (OVCFs), many patients still complain of mild back pain in the early postoperative period. Objectives: The aim of this study was to assess the effect of early limited activity (LA) on prognosis after bipedicular small-cement-volume (i.e., PVP) to treat single-segment acute OVCFs. Study Design: A prospective study and retrospective observations were performed on 125 patients with a minimum of 1 year of follow-up. Setting: A university hospital orthopedics and pathology departments. Methods: All patients were allocated into an LA group (n = 64) and an unlimited activity group (ULA group, n = 61). Patients in the LA group were suggested to keep time of off-bed activity < 4 hours per day in the first 3 weeks postoperatively. Patients in the ULA group did not limit activity. The demographic, clinical, and radiologic outcomes were assessed, such as pain intensity Numeric Rating Scale (NRS-11) and vertebral height ratio (i.e., fractured vertebral height/adjacent nonfractured vertebral height). Based on outcomes following surgery, all patients were classified as responders (NRS-11 score 1-day postoperation < 50% of preoperative NRS-11 score) or low responders (NRS-11 score 1-day postoperation ≥ 50% of preoperative NRS-11 score). Results: The demographic results and complications were similar. In the LA group, NRS-11 scores at 1 and 3 months postoperation respectively were 2.23 ± 0.42 and 1.46 ± 0.40, and corresponding scores respectively were 2.85 ± 0.80 and 1.73 ± 0.77 in the ULA group, and there was a difference in the 2 groups in both time points (P < 0.05). At 12 months postoperation, anterior and middle vertebral height ratio respectively were 78.42% ± 3.52% and 82.37% ± 3.49% in the LA group, which were higher than 76.87% ± 3.68% and 81.10% ± 3.31% in the ULA group (P < 0.05). Thirty-two cases were low responders. Among those, NRS-11 scores at 1 and 3 months postoperation respectively were 2.29 ± 0.45 and 1.53 ± 0.46 in the LA group, which were lower than 3.67 ± 0.80 and 2.56 ± 0.79 in the ULA group (P < 0.05), and at 12 months postoperation, anterior vertebral height ratio was 79.81% ± 3.25% in the LA group and 75.60% ± 3.50% in the ULA group (P < 0.05). Limitations: First, some patients lacked the results of bone mineral density during follow-up; second, the limited time in our study was chosen from our previous working experience, which may lack an objective basis; third, NRS-11 is solely used as an indicator of clinical outcomes in our study; finally, our next studies can increase the sample size to improve the clinically difference. Conclusions: LA in the early period after PVP can help patients achieve more pain relief postoperatively and maintain better vertebral shape, especially for low responders. Key words: Osteoporotic vertebral compression fractures, percutaneous vertebroplasty, Numeric Rating Scale, vertebral height, responders, low responders, limited activity, complications