Risk factors of implant?related complications in adult degenerative scoliosis with posterior long segment internal fixation / 中华骨科杂志

ABSTRACT

Objective To analyze the risk factors of implant?related complications in adult patients with adult degenera?tive scoliosis (ADS) who underwent long?level internal fixation. Methods This was a retrospective study that analyzed 99 cases of adult degeneration scoliosis patients who underwent long level posterior pedicle screw fixation in our hospital between June 2013 and January 2016. The internal fixation and related complications were evaluated by measuring and analyzing the radiograph?ic data of the postoperative X?ray films. The timepoints of measurement were pre?operation, before discharge, half a year, 1 year, when complications occur and the final follow?up after operation. Implant?related complications included proximal junctional ky?phosis (PJK), proximal junctional failure (PJF), distal junctional kyphosis/failure (DJK/DJF), rod breakage in addition to other ra?diographic implant?related complications (that were not related to PJF) such as screw loosening, breakage or pullout, or interbody graft and hook or set screw dislodgements seen on follow?up radiographs. The incidence of postoperative implant?related complica?tions was counted. All the cases included in the study were divided into the complication group and the non?complication group. Statistical difference between groups at different follow?up time point was analyzed. Potential risk factors were identified using uni?variate testing. Multivariate Logistics regression was used to analyze the independent risk factors for implant?related complica?tions. The postoperative functional scores were assessed using the Oswestry Disability Index (ODI), Japanese Orthopaedic Associa? tion Scores (JOA), Visual Analogue Scale (VAS), and Lumbar Stiffness Disability Index (LSDI). Functional scores were tested us?ing group t tests. Patients were divided into groups according to PI-LL<10°, 10°-20°and>20°. The preoperative and postoper?ative radiographical parameters and clinical function score among each groupwere compared.The best PI-LL matching value was verified by analyzing the effect of long?segment fusion orthopedics on ADS. Results Ninety?nine ADS patients who underwent long level posterior fixation were included. The incidence of patients with mechanical complications was 30.3%. Univariate analy?sis showed that chronic risk factors of postoperative implant?related complications after surgery of ASD included diabetes ( OR=3.52, P=0.001) and blood transfusion ( OR=2.61, P=0.030); surgical risk factor isosteotomy ( OR=4.33, P=0.000); preoperative im?aging risk factor was preoperative SVA ( OR=1.03, P=0.000); the risk factors for increased risk of the implant?related complications included anemia ( OR=1.17, P=0.810), cardiac complications ( OR=1.80, P=0.290) and hospital stay ( OR=1.11, P=0.110). Indepen?dent predictors identified on multivariate Logistics regression modeling included osteotomy ( OR=3.05,P=0.032), and preoperative SVA ( OR=1.03,P=0.007). The radiographical parameters and clinical function scores of the PI-LL 10°-20° group were better than or partially superior to those of the PI-LL<10°group and the PI-LL>20°group. The postoperative SVA of the PI-LL 10°-20°group was significantly lower than that of the PI-LL<10°group (t=2.399, P=0.020) and the PI-LL>20°group (t=-3.074, P=0.005). The incidence of implant?related complications in the PI-LL 10°-20°group was significantly lower than that in the PI-LL<10°group (t=1.584, P=0.003). Survival analysis showed that the PI-LL 10°-20°group was significantly better than the PI-LL<10°group (χ2=7.782, P=0.005), while the PI-LL 10°-20°group had better survival than PI-LL>20°group, althoughthatwas not statistically significant (χ2=2.542, P=0.111). Conclusion Risk factors of postoperative implant?related complications after sur?gery of ASD included osteotomy and preoperative SVA. Patients with one or more of these risk factors should be informed of the risk increase with informed consent. Patients with PI-LL between 10°and 20°had better postoperative radiographical parame?ters and clinical functional scores. They should be optimized preoperatively and followed up closely during the postoperative period.