Prevalence and key radiographic spinal malalignment parameters that influence the risk for gastroesophageal reflux disease in patients treated surgically for adult spinal deformity

BACKGROUND Gastroesophageal reflux disease (GERD) is a factor that has a significant negative impact on the quality of life (QoL). Vertebral fractures and/or spinal malalignment may influence the frequency of GERD. However, the epidemiology and pathology of GERD in patients with adult spinal deformity (ASD) are still largely unknown. To establish the optimal surgical strategy for GERD in patients treated surgically for ASD, we sought to clarify the GERD prevalence, determine radiographically which spinal malalignment parameters influence GERD risk, and evaluate GERD improvement postoperatively. METHODS Seventy-one consecutive patients with ASD who were treated with thoracolumbar corrective surgery and followed up for at least 1 year were enrolled. GERD was diagnosed by a gastroenterologist based on proton pump inhibitor medication response and/or an FSSG score > 8 points. Full-length lateral radiographs in a standing posture and in a supine, fulcrum backward-bending (FBB) position were taken preoperatively and 1 year postoperatively, and radiographic parameters were obtained. Correlations between radiographic parameters and FSSG scores were determined by Pearson's correlation coefficient. Multivariate logistic regression analyses were performed to evaluate the odds ratio (OR) with a 95% confidence interval (95% CI) for potential risk factors for GERD. RESULTS Patients were classified into two groups based on GERD symptoms, with 37 (52%) in the GERD+ group. Thoracolumbar kyphosis (TLK) in the FBB position was significantly more common in the GERD+ versus the GERD- group. Multivariate logistic regression analysis showed that lumbar lordosis (LL) and TLK curve in the FBB position significantly influenced the presence of GERD. Other factors showed no association with GERD. Significant improvements in FSSG scores were noted 1 year postoperatively. However, 20 (28.2%) patients still had GERD symptoms. The postoperative TLK curve was highly significantly correlated with FSSG scores 1 year postsurgery. CONCLUSIONS Of the 71 patients treated surgically for ASD, 37 (52%) had a high frequency of GERD symptoms. An inflexible thoracolumbar curve with increased TLK in the FBB position was significantly associated with GERD symptoms. Despite significant improvements in FSSG scores postoperatively, insufficient correction of TLK might be a risk factor for persistent GERD symptoms.