Background: The long term radiological status of screw fixation following scoliosis surgery with all pedicle screw\nconstruct is not previously studied.\nAim: To evaluate the incidence of loosening (implant failure) evaluated with low-dose CT two years following scoliosis\nsurgery.\nStudy design: Retrospective study.\nMethods: 81 consecutive patients with adolescent idiopathic scoliosis (AIS), aged 18 Ã?± 3 years at 2 years follow-up\n(83% were female), subjected for scoliosis corrective surgery with all pedicle screw construct (total of 1666 screws) has\nbeen examined with plain radiography and with low dose CT 6 weeks and 2 years postoperatively.\nResults: In 26 out of 81 (32%) patients there were signs of loosening of one or more screws, a maximum 3 screws.\n47 out of 1666 (2.8%) screws showed evidence of loosening. Preoperative Cobb angle was 56Ã?° among patients with\nloosening compared with 53Ã?° among patients with no evidence of loosening (P = 0.288). In males there were signs of\nloosening in 8 out of 14 (57%) and in females 18 out of 67 (27%), (P = 0.027). Among cases with loosening, 14% had\nsuboptimal screw placement at the first postoperative CT compared with 11% among patients with no evidence of\nloosening (P = 0.254). One patient with a loosened L4 screw had neurological deficit and subjected for revision of the\nconstruct. Out of 26 patients with evidence of loosening, 5 patients reported minor pain or discomfort, 1 patient had a\nminor proximal junctional kyphosis of about 15Ã?° and 3 patients showed evidence of pull-out of 3ââ?¬â??5 mm at the upper\nend of the construct but no clinical complaint. With plain radiography loosening could be observed only in 11 out of\n26 cases, 5 were in the lumbar region.\nConclusions: In a consecutive series of 81 cases with AIS who had underwent scoliosis surgery, one third showed,\n2 years after the intervention, minor screw loosening. Males were more prone to develop screw loosening. In CT\nsystem that enables low-dose protocol, CT is recommended for the evaluation of evidence of screw loosening.
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