title: Posterior scoliosis correction for adolescent idiopathic scoliosis using side-opening pedicle screw-rod system utilizing the axial translation technique.
abstract: BACKGROUND
  Though adequate literature is present depicting the results of pedicle screw-rod instrumentation using top loading systems for correction of adolescent idiopathic scoliosis (AIS), using the rod rotation technique, few published data is available regarding side loading systems used for a similar purpose. We report a retrospective study of a cohort of patients with strict inclusion criteria who underwent surgical correction of AIS with side-opening pedicle screw-rod posterior instrumentation using the axial translation technique of curve correction to assess the efficacy of side opening system for scoliosis correction with regards to patient satisfaction, Cobb's angle correction and spinal balance.
  
  
  METHODS
  Clinical and radiological outcomes were measured in 14 consecutive patients (3 males, 11 females) with an average age of 14.0 years (range 9 to 23 years). They were followed up for an average period of 13.0 months (range - 2.2 to 28.5). All patients underwent posterior instrumentation only with pedicle screws used as anchor points. Hybrid constructs using hooks/wires or curves requiring anterior release were excluded from the study. All levels were not instrumented - more screws were put on the concavity and in the peri-apical region. Radiological evaluation was done by whole spine standing AP, lateral radiograms preoperatively and 1, 3, 6 and12 months after surgery. Cobb's angles were measured and the spinal balance was noted. Clinical evaluation was done by SRS questionnaire. The complications were documented.
  
  
  RESULTS
  The mean preoperative Cobb's angle was 58.35 degrees (range - 44 to 72 degrees ), which came down postoperatively to 23.45 degrees (range - 10 to 38 degrees ) signifying a mean correction of 59.57% (range - 26.92 to 76.17%). Clinical outcomes were evaluated using the SRS - 30 questionnaires. The values of mean pre- and postoperative scores are 3.68 and 4.18, showing an improvement of 0.5 points. Other than one patient of superficial wound infection, which healed with antibiotics, there was no major complication. No patient had neurological deterioration.
  
  
  CONCLUSIONS
  Side-opening spinal instrumentation systems, using the axial translation technique, achieved good clinical and radiological outcome for patients of AIS.
authors.affiliation: Park Clinic, Neurosciences Division, Kolkata, India.
authors.forename: Saumyajit
authors.initials: S
authors.lastname: Basu
authors.forename: Sreeramalingam
authors.initials: S
authors.lastname: Rathinavelu
authors.forename: Prashant
authors.initials: P
authors.lastname: Baid