Original ArticleMultilevel Posterior Column Osteotomies Are Not Inferior For the Correction of Rigid Adult Spinal Deformity Compared with Pedicle Subtraction Osteotomy
Introduction
Posterior column osteotomy (PCO) refers to resection of bilateral facets and the ligament flavum, followed by posterior compression.1, 2 PCO includes Smith-Petersen osteotomy (SPO) and Ponte osteotomy. Between 9.3° and 10.7° can be corrected per level using PCO to treat a kyphotic deformity.2, 3, 4, 5, 6 In Scheuermann kyphosis, deformities can be effectively corrected with PCO.4, 5, 7 Moreover, PCO can be useful for correcting spinal deformities at the scoliotic apex in adolescent idiopathic scoliosis.8, 9, 10, 11
Degenerative changes in the spine include disc degeneration, osteophyte formation, facet hypertrophy, ligament thickening, and ligament calcification. As a result of these changes, patients with adult spinal rigid or fixed deformity (ASD) have rigid spinal segments. Typically, pedicle subtraction osteotomy (PSO) has been used in ASD surgery.12, 13
PCO is a shortening procedure of the posterior column between the vertebral bodies. Therefore, the ability to perform a PCO depends on the following factors: an elastic intervertebral disk, appropriate disc height, and relatively high flexibility of the disk. Because of these factors, many patients with ASD do not meet the requirements for the use of PCO. However, because the criteria regarding the required flexibility of spinal segments before PCO are not available, PCO may be used for the treatment of patients with ASD. Few reports have explored the use of PCO in less flexible or rigid ASDs. The purpose of this study was to show the usefulness of PCOs for the treatment of rigid ASDs. We analyzed radiographic and clinical outcomes to assess the corrective potential of multilevel PCO. We compared outcomes with those from single-level PSOs, because this surgery is widely used in the treatment of ASD.
Section snippets
Patient Population
Data from 70 patients with spinal deformity who had undergone spinal deformity surgery in a single institution between June 2012 and May 2016 were analyzed. The inclusion criteria were as follows: 1) age at surgery ≥50 years; 2) sagittal vertical axis (SVA) >5 cm; 3) pelvic incidence (PI)–lumbar lordosis (LL) in whole-spine lateral standing radiograph (LL(Stand)) >10°; 4) rigid spinal deformity with mobile segments in the lumbar spine; 5) performance of either a multilevel PCO or a single-level
Demographics
The mean age of the patients included in this study was 69.7 ± 6.3 years. No significant differences in age at surgery, gender, fused level, or bone mineral density T score were observed between the 2 groups (Table 1). However, in terms of diagnosis, the number of patients with degenerative flat back was significantly larger in the PCO group than in the PSO group (PCO, 26 [74.3%] vs. PSO, 15 [42.9%]; P = 0.015). The number of patients with postoperative flat back was lower in the PCO group than
Discussion
In this study, relatively older patients (69.7 ± 6.3 years at surgery) were investigated. Compared with in younger patients, the adult spine is characterized by degenerative changes. Zibrel et al.21 reported that as intervertebral disc degeneration progresses, the stiffness of spinal movement in the flexion-extension, axial rotation, and lateral bending increases. In addition to disc degeneration, the degenerative changes include facet joint hypertrophy and osteophyte formation, as well as
Conclusions
Multilevel PCOs for the correction of rigid ASDs were found to be slightly superior in terms of clinical outcomes, but similar in radiographic outcomes, compared with PSO. Thus, multilevel PCOs can be a viable surgical option for the treatment of rigid ASDs with a mobile segment.
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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.