Preoperative calculation of the necessary correction in sagittal imbalance surgery: validation of three predictive methods.
BACKGROUND
Surgery for correction of sagittal imbalance has frequent adverse events and complications. The most frequent cause of failure is inadequate correction of imbalance. The aim of this study is to verify the accuracy of three published methods (exact method by Ondra, FBI method by Le Huec and spinofemoral angle method by Lamartina) to preoperatively calculate the needed correction.


METHODS
This is a retrospective cohort study.


METHODS
Fifteen patients treated for correction of sagittal imbalance, with preoperative and postoperative lateral standing whole spine radiographs, were identified. Preoperative calculation of the amount of needed correction has been done using these methods. In postoperative X-rays, the amount of correction obtained with and the degree of correction of sagittal imbalance have been measured.


CONCLUSIONS
The FBI and SFA methods obtain equivalent calculations of the amount of needed correction. The estimated correction angle with both methods is higher than that calculated with the exact trigonometric method. The difference between the latter and the former methods is equivalent to the observed excess of pelvic tilt.
IVth Spine Surgery Division, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy, pberjano@gmail.com.
P
P
Berjano
R
R
Cecchinato
M
M
Damilano
C
C
Morselli
V
V
Sansone
C
C
Lamartina
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D006801:Humans; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013121:Spinal Curvatures / Q000000981:diagnostic imaging* / Q000601:surgery*; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery*