Choice of Lowest Instrumented Vertebras for Lenke I Adolescent Idiopathic Scoliosis Orthopedics

To discuss the impact of different lowest instrumented vertebras on the effect of posterior spinal pedicle screw-rod orthopedics for treatment of Lenke I adolescent idiopathic scoliosis. 45 patients with adolescent idiopathic scoliosis (AIS) who received posterior pedicle screw-rod orthopedics from July 2011 to September 2015 were analyzed retrospectively. All patients were divided into touched vertebra group (n=21 cases; 6 M and 15 F) and stable vertebra group (n=24 cases; 7 M and 17 F) according to the choice of different lowest instrumented vertebras. The indexes of the coronal and sagittal spinal imaging before and after operation as well as in the last follow-up were analyzed and SRS-22 questionnaire was performed to evaluate the curative effect. Through a 6-36-month follow-up visit, no significant difference was found in the pre-operative indexes (Cobb angle and pre-operative TS, SVA, TK and LL) of the coronal and sagittal spinal imaging between the two groups (P>0.05). Meanwhile, there was no statistical difference in the spinal coronal parameters (i.e., Cobb angle, TS, pre-operative thoracic-waist/waist scoliosis, pre-operative flexibility of thoracic scoliosis, correction rate and loss rate) after operation and in the last follow-up visit between the two groups (P>0.05). In touched vertebra group, the coronal spinal parameters (e.g., thoracic-waist/waist scoliosis) after operation and in the last follow-up visit were significantly higher than those of stable vertebra group (P<0.05) while there was no statistical difference in postoperative SVA between the two groups (P>0.05). In the aspect of fusion segments, the touched vertebra group saved one centrum relative to stable vertebra group (P<0.05). The postoperative SRS-22 scores for living quality of both groups were significantly decreased compared with the pre-operative, in which the score was decreased from the preoperative 51.0 to 29.0 in touched vertebra group and from 50.9 to 28.7 in stable vertebra group (both P<0.05), but both the preand post-operative scores were not significantly different between the two groups (P>0.05). In order to treat Lenke I AIS patients with posterior pedicle screw-rod orthopedics, touched vertebra should be used as lowest instrumented vertebra as it can not only obtain the similar therapeutic effect to stable vertebra, but also shorten the fixed segments.