脊椎ジャーナル

Effect of Growing Systems on Hyperkyphotic Deformities

Abstract

Greggi T, Maredi E, Vommaro F, Lolli F, Martikos K, Giacomini S, Di Silvestre M, Baioni A, Scarale A, Morigi A and Bacchin MR

Study Design: Retrospective mini case series, single centre.

Objective: To report the efficacy of growing spine distraction-based implants in the treatment of hyperkyphotic and kyphoscoliotic early-onset deformities during initial surgery and lengthening.

Background: Growth-sparing implants, such as growing rod and VEPTR-like systems, are distraction-based systems involving repetitive lengthening procedures, which mean that hyperkyphosis may be a relative contraindication in the treatment of early onset deformities. The role of growing implants in the treatment of coronal deformities is now acknowledged, but there are very few studies on the effect of both primary surgery and several lengthening procedures on sagittal balance.

Methods: Twenty paediatric patients affected with kyphoscoliosis and surgically treated with growing systems were retrospectively reviewed. Etiology was heterogeneous; there were 10 males and 10 females, aged 7 yrs on average. The dual growing rod technique was used in 9 cases, VEPTR in 11. Preoperative main thoracic scoliosis averaged 64° (range, 10° to 100°) and thoracic kyphosis 71° (60° to 90°),67° in patients with Growing Rods and 77° in those with VEPTR with a history of EOS (Early Onset Scoliosis). At Follow-up ranging from 6 months to 7 years, 31 lengthening procedures had been performed (1.9 per patient). For the purpose of this study, patients were divided into two groups: Growing-Rod Group (GR-group) and VEPTR-like-Group (VL-group); preoperative and postoperative degrees of scoliosis and kyphosis were measured, as well as final results at follow-up.

Results: A significant decrease in scoliosis and kyphosis was observed during initial surgery, then a significant loss of correction occurred during the FU period, first on coronal and then on sagittal plane, both in GR-group and in VL-group; however, in the VL-group the loss of correction in terms of kyphosis was significantly higher than in the other group. In particular, after initial surgery, in GR-group thoracic kyphosis was corrected from 67° to 44°, whereas in VLgroup from 77° to 60°. After the lengthening procedures, a loss of correction occurred: in GR-group, thoracic kyphosis increased from 44° to 50° (p<0.05), whereas in VL-group from 58° to 68°. 15 minor complications occurred in 8 patients and revision surgery was performed in 7.

Conclusion: Growing implants can be safely used in the treatment of EOS, even in the presence of hyperkyphosis. Distraction procedures inevitably led to the loss of some correction on sagittal plane which was observed at follow-up and was higher in the VL-group. In any case, the final result was mostly related to the correction of kyphosis achieved during initial surgery and in any case the loss of correction was always lower than the first correction obtained. When the cantilever maneuver is performed during initial surgery, growing rods seem to grant a better sagittal plane restoration compared to VEPTR. The complication rate turned out to be a little higher (30%) than the rate observed after general surgical treatment of EOS, thus confirming an increase in complication rate when hyperkyposis is present; the most frequently encountered complication was proximal failure.