A Nomogram to Predict the Occurrence and Development of Postoperative Neck Tilt in Lenke I and II AIS Patients.

OBJECTIVE

To investigate the risk factors and to construct a nomogram for the prediction of postoperative neck tilt (PNT) in patients with Lenke I and II adolescent idiopathic scoliosis (AIS).

METHODS

A total of 95 patients with Lenke I and II AIS who underwent posterior segmental spinal instrumentation and fusion between the years 2010 and 2018 (with an average 2-year follow-up) at a single institution were retrospectively investigated. The full spine X-rays of patients were measured preoperatively, postoperatively, and at the final follow-up. Variables were compared between the PNT group (n = 33) and the non-PNT group (n = 62), and univariate and multivariate logistic regressions were performed to identify the independent predictors for the occurrence of PNT. The discrimination and calibration of the nomogram were validated by the receiver operating characteristic curve and calibration curve.

RESULTS

Variables including the preoperative neck tilt, postoperative upper instrumented vertebrae imbalance, postoperative T1 tilt, and decreasing values in the main thoracic curve (ΔMTC) minus decreasing values in the proximal thoracic curve (ΔPTC) (ΔMTC - ΔPTC) were identified as the predictors for the nomogram. The area under the receiver operating characteristic curve was 0.900 (95% confidence interval, 0.857-0.932). Meanwhile, the calibration curve revealed good agreement, and the Hosmer and Lemeshow test determined that the model was well fitted.

CONCLUSIONS

Preoperative neck tilt, postoperative upper instrumented vertebrae imbalance, postoperative T1 tilt, and ΔMTC-ΔPTC are predictors for the nomogram. The nomogram can provide surgeons with a simple and effective tool to predict the occurrence and development of patients with PNT in Lenke I and II AIS.