Pain and disability following fusion for idiopathic adolescent scoliosis: prevalence and associated factors.

 The high percentage of patients reporting no pain or mild pain may suggest overall success of the procedures. Although an association between instrument type and pain was seen, unmeasured factors that contributed to the decision of what instrument to use may confound the relationship. From these data a causal inference cannot be made.Final class of evidence-prognosisSTUDY DESIGNProspective CohortRetrospective Cohort•Case controlCase seriesMETHODSPatients at similar point in course of treatment•F/U ≥ 85%Similarity of treatment protocols for patient groupsPatients followed up long enough for outcomes to occur•Control for extraneous risk factors•*Overall class of evidenceIIIThe definiton of the different classes of evidence is available on page 55.*Potentially confounding factors were systematically explored and considered for stratified analysis as appropriate.