Prevention of the Crankshaft Phenomenon with Posterior Pedicle Screw Fixation in Scoliosis of the Skeletally-Immature Spine / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate the results of posterior segmental pedicle screw fixation in skeletally immature patients with scoliosis. SUMMARY OF LITERATURE REVIEW Scoliosis correction, in the immature spine, frequently necessitates additional anterior surgery to prevent the crankshaft phenomenon. With the advent of posterior segmental pedicle screw fixation, it is unclear whether an additional anterior procedure will be required. MATERIAL AND METHODS: Seventeen scoliosis patients (10 idiopathic, 4 congenital and 3 others; 3 males and 14 females) were treated with segmental pedicle screw fixation only. Their results were reviewed for a deformity progression of more than 10 degrees, a rib vertebra angle difference (RVAD) progression of more than 10 degrees, and evidence of adding-on. All the patients had a 0 Risser index at the time of the operation. The mean age and follow-up times were 10.4, ranging from 7.2 to 11.8 years old, and 4.0, ranging from 3.0 to 5.4 years, respectively. RESULTS: The mean preoperative thoracic curve of 55 degrees was corrected to 22 degrees (58% correction) at last follow-up and the nonstructural lumbar curve of 31 degrees was corrected to 10 degrees (67% correction) at last follow-up. Preoperative thoracic kyphosis of 28 degrees was improved to 34 degrees at last follow-up. The RVAD were 23 degrees and 13 degrees, preoperatively and postoperatively, respectively. No patient showed a progression of 10 degrees or more in the postoperative coronal curve or RVAD. One patient had a progression of the deformity caudal to the instrumented segments. There were no neurological or screw-related complications. CONCLUSIONS: Posterior segmental pedicle screw fixation in skeletally immature patients with scoliosis may be effective in preventing the crankshaft phenomenon.