Selective application of navigation templates in idiopathic scoliosis: technical and hronometric features

Abstract

Objective. To evaluate short-term result of selective navigation templates application in idiopathic scoliosis surgery.Material and Methods. A total of 12 patients aged 14–17 years with idiopathic scoliosis were included in the study. Group A included 6 patients treated with selective application of navigation templates for pedicle screws insertion in the most difficult zones. Group B (control) included 6 patients in whom all the pedicle screws were placed with free-hand technique. Number of screws inserted was 16–20 per patient. There was no significant difference between the groups in sex, age, Cobb angle, number of vertebrae instrumented, number of pedicle screws and laminar hooks. Surgery duration, blood loss, absolute and relative correction were compared. In Group A, duration of the 3D-objects fabrication and printing, as well as pedicle screw accuracy based on 2-mm increment grading system were evaluated.Results. Selective application of navigation templates as compared with total free hand screws placement significantly reduced surgery duration. Difference in blood loss and deformity correction was not significant. A total of 107 pedicle screws were placed in Group A, 48 of them with navigation templates and 59 by free-hand technique. Average pedicle width in screw installation with navigation templates was 4.28 ± 1.43 mm, and in that with free-hand technique 6.53 ± 1.72 mm, with significant difference. Accurate screw placement with navigation templates and by free-hand technique were 93.7 % and 88.0 %, respectively, with no significant difference. Duration of 3D-objects manufacturing was 1419 ± 190 minutes. Active operator’s involvement was required in about 10 % of the while.Conclusion. Selective application of a pair of two-level navigation templates for most difficult pedicles in idiopathic scoliosis significantly reduces surgery duration. Difference in blood loss and deformity correction is insignificant. Refusal of total templates usage for combination of navigation templates for selected difficult pedicles and free-hand technique for the rest is an option for shortening the preoperative preparation, but provides screw placement accuracy comparable with total templates usage (92.5–97.6 % as reported).