Coronal balance and surgical strategy of pediatric lumbar and lumbosacral hemivertebrae

English Keywords:Pediatric spinal deformity  Congenital scoliosis  Coronal balance  Lumbosacral vertebra  Hemivertebrae

English Abstract:

  【Abstract】 Objectives: To asses the coronal balance in pediatric lumbar and lumbosacral hemivertebrae(HV), and to evaluate the surgical outcome of one stage posterior hemivertebra resection and pedicle screw instrumentation. Methods: A retrospective review of 14 pediatric patients receiving surgical treatment in our department from January 2015 to December 2013 was carried out. The mean age at the time of surgery was 7.8±3.3 years(range, 3-10 years). The hemivertebrae involved L4 in four cases, L5 in seven cases and S1 in three cases. Patients were classified into three groups according to the preoperative coronal balance. Group A had coronal balance, the distance between C7 plumb line and central sacral vertical line(CSVL) was less than 2cm. Group B was termed as C7 plumb line located at contralateral side of HV and deviated from CSVL of more than 2cm. Group C was also C7 plumb line deviated from CSVL of more than 2cm but located at ipsilateral side of HV. All patients underwent one stage posterior HV resection and pedicle screw instrumentation. In group A, distraction at concavity and compression at convex side were used equally to maintain coronal balance. In group B, compression and gap closing following HV resection was the main procedure. In group C, additional distraction at convex and compression at concave side were used at L5-S1 segment, following HV resection and gap closing. Results: The mean follow-up period was 33±12 months(range, 24-68 months). 4 cases(29%) had preoperative coronal balance, while the other 10 cases had preoperative imbalance. The coronal Cobb angle improved form 36.8°±6.9° at preoperation to 12.1°±8.0° at final follow-up(P=0.000), with a correction rate of 67.1%. The coronal balance improved from 30.6mm(range, 6-53mm) at preoperation, to 10.7±10.9mm(range, 0-4mm) at final follow-up(P=0.001). There were 4 cases in group A, 6 cases in group B, 4 cases in group C. All patients retained coronal balance except one case in group B developed coronal decompensation postoperatively. Conclusions: There is a high rate of coronal imbalance in pediatric lumbar and lumbosacral hemivertebra patients. One stage posterior hemivertebra resection and pedicle screw instrumentation is of highly satisfied.