Lonner, Baron S. MD*; Newton, Peter MD†; Betz, Randy MD‡; Scharf, Carrie BA§; O’Brien, Michael MD§; Sponseller, Paul MD∥; Lenke, Lawrence MD¶; Crawford, Alvin MD‡‡; Lowe, Tom MD**; Letko, Lynn MD††; Harms, Jurgen MD††; Shufflebarger, Harry MD§
Study Design. A retrospective multicenter review of 78 patients with Scheuermann’s kyphosis treated operatively was conducted.
Objective. The purpose of this study was to evaluate correction of sagittal alignment, maintenance of correction, and occurrence of, and etiologic factors associated with, junctional kyphosis in patients managed operatively for Scheuermann’s kyphosis.
Summary of Background Data. There is a paucity of literature regarding the surgical treatment of Scheuermann’s kyphosis using current implant systems and operative techniques. Junctional kyphosis has been shown to occur in up to one third of patients. Factors causing junctional kyphosis have not been clearly elucidated. Loss of correction has been variable based on the technique used. No clear-cut advantages or disadvantages have been shown for the use of anterior release.
Methods. Kyphosis, lordosis, C7 sagittal plumbline, apical translation, junctional sagittal alignment, and pelvic incidence were assessed among other radiographic parameters from a centralized database. The incidence of junctional kyphosis and its association to the above parameters and to fusion levels were assessed. Complication rates and differences between patients undergoing combined anteroposterior surgery and those having posterior surgery alone were evaluated.
Results. Of the 78 patients, 42 underwent combined anteroposterior procedures (Group 1) and 36 had posterior surgery only (Group 2). Mean age was 16.7 years. Overall, the greatest Cobb kyphosis of 78.8° was corrected to 51.4° at follow-up. Preoperative kyphosis was 82.6° and 74.4° for Groups 1 and 2, respectively (P < 0.001) and 55.8° and 46.2° at follow-up (P = 0.000). Loss of correction was 3.2° (not significant) and 6.4° (P = 0.000), respectively. Lordosis corrected from −65.5° to −51.7°.Proximal and distal junctional kyphosis of ≥10° occurred in 25 (32.1%) and 4 (5.1%), respectively. The development of a proximal junctional kyphosis correlated directly with kyphosis at follow-up and indirectly with percent correction. Among patients with proximal junctional kyphosis, the magnitude of junctional kyphosis correlated directly with the degree of pelvic incidence. Pelvic incidence correlated directly with lumbar lordosis but not kyphosis. Twelve complications occurred in 12 patients, including posterior wound infection (1), distal (2), and proximal (1) junctional kyphosis, and pseudarthrosis (1), those requiring reoperation.
Conclusion. This is one of the largest reported series of Scheuermann’s kyphosis treated operatively to our knowledge. A high rate of junctional kyphosis, especially at the proximal end, is associated with surgery for Scheuermann’s kyphosis using current techniques. Proximal junctional kyphosis is associated with higher magnitude of kyphosis at follow-up, less percent correction; its magnitude correlated directly with pelvic incidence. Loss of correction is less in patients undergoing combined anteroposterior surgery. Pelvic incidence correlates directly with lordosis but not kyphosis, suggesting that these parameters are not causative of Scheuermann’s kyphosis.
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Spine: 15 November 2007 – Volume 32 – Issue 24 – pp 2644-2652