Retrospective analysis of prospectively collected multicenter series.
To evaluate the sagittal profile of surgically treated adolescent idiopathic scoliosis (AIS) patients.
With the increasing popularity of segmental pedicle screw spinal instrumentation, thoracic kyphosis (TK) is often sacrificed to achieve coronal and axial plane correction.
Radiographs of AIS patients with a Lenke type 1 deformity and minimum 2-year follow-up after selective thoracic fusion (lowest instrumented vertebra of T11, T12, or L1) were evaluated. Changes in TK were correlated with changes in lumbar lordosis (LL). Patients were divided according to approach (open/thoracoscopic anterior vs. posterior). Analysis of variance was used to compare pre and postoperative radiographic measures.
Two hundred fifty-one patients (age: 14 ± 2 years) were included. Sixty seven percentages of the patients had anterior surgery (97 open anterior, 71 thoracoscopic) and 33% (83 patients) had posterior spinal fusion. A decrease in postoperative TK was significantly correlated (P ≤ 0.001) with a decrease in LL at first erect (r = 0.3), 1 year (r = 0.4) and 2 years (r = 0.4), independent of surgical approach. LL decreased significantly at the first erect regardless of approach (P = 0.003); however, at 2-year postoperative TK and LL were significantly decreased after a posterior approach (P ≤ 0.001) when compared with an anterior approach that added kyphosis. The decrease in LL (5.6° ± 9.7°) was nearly twice the decrease in TK (2.8° ± 11.4°) in the posterior group at 2-years.
Given that thoracic AIS is often associated with a preexisting reduction in TK, ideal surgical correction should address this deformity. Procedures which further reduce TK also reduce LL. It is unclear if the loss of LL from thoracic scoliosis correction will compound the loss of LL that occurs with age and lead to further decline in sagittal balance. With this concern, we recommend a posterior column lengthening and/or an anterior column shortening to achieve restoration of normal TK and maximal LL.
Analysis of changes in the sagittal profile in surgically treated patients with adolescent idiopathic scoliosis showed that a decrease in postoperative thoracic kyphosis results in a decrease in lumbar lordosis. A premature, iatrogenic loss of lumbar lordosis may predispose patients to develop flat back deformity and unbalanced forward sagittal alignment.
From the *Department of Orthopedic Surgery, University of California, San Diego; †Department of Orthopedics, Rady Children's Hospital-San Diego, CA; ‡Department of Orthopedics, WA University, St. Louis, MO; §Department of Orthopedics, Woodridge Spine Orthopedics, Wheat Ridge, CO; ¶Department of Orthopedics, Cincinnati Children's Hospital, Cincinnati, OH; ∥Department of Orthopedics, Shriners Hospital for Children, Philadelphia, PA; and **Scoliosis Associates, New York, NY.
Acknowledgment date: March 20, 2009. First revision date: June 18, 2009. Second revision date: July 24, 2009. Acceptance date: July 27, 2009.
The device(s)/drug(s) that is/are the subject of this manuscript is/are not FDA-approved for this indication and is/are commercially available in the United States (off-label use in pediatrics).
Corporate/Industry funds were received in support of this work. One or more of the author(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript: e.g., honoraria, gifts, consultancies, royalties, stocks, stock options, decision making position.
This study was conducted at Rady Children's Hospital and Health Center San Diego, CA.
Supported by a grant to the Harms Study Group from DePuy Spine Inc.
Thomas Lowe, MD, is deceased.
Address correspondence and reprint requests to Peter O. Newton, MD, 3030 Children's Way, Ste 410, San Diego, CA 92123; E-mail: email@example.com