Elsevier

World Neurosurgery

Volume 105, September 2017, Pages 249-256
World Neurosurgery

Original Article
Anterior Column Realignment has Similar Results to Pedicle Subtraction Osteotomy in Treating Adults with Sagittal Plane Deformity

https://doi.org/10.1016/j.wneu.2017.05.122Get rights and content

Objective

Anterior column realignment (ACR) is a minimally invasive surgical technique used for the correction of adult sagittal plane deformity. ACR is performed via a minimally invasive lateral transpsoas approach with anterior longitudinal ligament release and hyperlordotic cage placement. The objective of this study was to compare radiographic outcomes and complications in patients treated by ACR or Pedicle subtraction osteotomy (PSO).

Methods

Patients who underwent ACR were matched with patients from a retrospective PSO dataset, by pelvic incidence, lumbar lordosis, and thoracic kyphosis. Inclusion criteria included pelvic incidence and lumbar lordosis mismatch > 10°, pelvic tilt > 25°, and/or C7 sagittal vertical axis >5 cm, and minimum 1-year follow-up.

Results

All (n = 17) patients who underwent ACR underwent second-stage open posterior instrumented fusion. There were no differences in baseline demographic or radiographic parameters. Both groups were found to have significant improvement from preoperative to final follow-up for lumbar lordosis, T1 spinopelvic inclination, and T1 pelvic angle. Pelvic tilt did not improve with PSO (31° to 28°) at final follow-up but did improve in ACR group (34° to 25°). No differences were identified at 3-month or final follow-up for lumbar lordosis (51° vs. 47°), pelvic tilt (25° vs. 28°), and T1 pelvic angle (23° vs. 24°). The group undergoing PSO achieved greater T1 spinopelvic inclination correction (8° vs. 1.9°). Patients who underwent ACR had significantly less estimated blood loss than patients who underwent PSO (1.6 vs. 3.6 L, respectively), but no difference in the overall major complication rates was found (35.3% vs. 41.2%, respectively).

Conclusions

ACR achieved similar radiographic results as PSO in a matched cohort with significantly less estimated blood loss and similar overall complication rate.

Introduction

Sagittal plane malalignment is common in adult spinal deformity (ASD) and is associated with significant disability.1 With increasing life expectancy, there are now a greater number of patients with ASD seeking operative treatment. Several radiographic parameters correlate with poor health-related quality of life (HRQOL) measures, including sagittal vertical axis (SVA) greater than 5 cm, a mismatch between pelvic incidence (PI) and lumbar lordosis (LL) of greater than 10°, a pelvic tilt (PT) greater than 25°, and T1 spinopelvic inclination (T1SPi) greater than 1°.2, 3

Restoration of these radiographic parameters to physiologic norms is necessary for achieving favorable surgical outcomes. For severe sagittal plane deformity, 3-column osteotomies, such as pedicle subtraction osteotomy (PSO), traditionally have been performed and result in significant improvements in HRQOL measures.4, 5 However, 3-column osteotomies also are associated with long operative times, significant blood loss, and major complication rates approaching 50%.4, 5, 6, 7, 8

There has been growing interest in applying minimally invasive surgical techniques to ASD correction in an effort to minimize complications. However, minimally invasive surgical techniques, particularly lateral lumbar transpsoas interbody fusion (LLIF), have been associated with inadequate restoration of sagittal plane radiographic parameters, which can lead to suboptimal clinical outcomes.9, 10, 11 In an attempt to address the high complication rates associated with PSO and to improve the corrective potential of the LLIF technique, the anterior column realignment (ACR) procedure was developed. ACR uses a standard LLIF approach with the addition of anterior longitudinal ligament (ALL) and annulus release and placement of a 20° or 30° lordotic interbody cage.12, 13, 14, 15, 16

In the current study, we compared the radiographic outcomes and complication rates of the ACR technique with PSO for the treatment of ASD. Propensity matching was applied generate 2 groups of patients with similar preoperative spinopelvic sagittal plane deformities. The primary objective of this study was to better understand the efficacy and safety of ACR in restoring spinopelvic alignment compared with a more traditional technique.

Section snippets

Study Design and Database

Seventeen adult patients with sagittal plane deformity (pelvic incidence and lumbar lordosis mismatch > 10°, PT > 25°, and/or C7 SVA > 5 cm) were identified in a single-center ACR database. Patients who underwent ACR were propensity matched with patients in a multicenter PSO database (N = 100 patients) by PI, LL, and thoracic kyphosis (TK). All patients had a minimum of 1-year postoperative follow-up. Patients with ACR and PSO had the respective corrective procedure performed at a single level

Demographic Information

Propensity matching established 2 groups of 17 patients for analysis. All patients who underwent ACR underwent second-stage open posterior instrumented fusion. Baseline demographics were similar between ACR and PSO groups regarding age (ACR: 62.9 vs. PSO: 56.5 years, P = 0.14), sex (ACR: 88.2% female vs. PSO: 70.6%, P = 0.398), and primary versus revision surgery (ACR: 89% revision, vs. PSO: 94%).

Surgical Strategy

The analysis of the surgical strategy revealed no significant difference in terms of number of

Discussion

Three-column osteotomies, such as PSO, are performed commonly for the correction of sagittal plane deformities. PSO is effective in reestablishing spinopelvic harmony and results in favorable long-term clinical outcomes. However, PSO is also associated with a very high complication rate. The incidence of major complications after 3-column osteotomy surgery has been reported to range from 25% to 59%.4, 5, 6, 7, 8

The ACR procedure was introduced as an alternative to the PSO for correcting

Conclusions

ACR is a minimally invasive technique that has been developed as alternative approach to sagittal plane deformity correction. In propensity-matched patients, ACR achieves similar sagittal plane correction as PSO with less blood loss. ACR is associated with a distinct complication profile, although with overall similar complication rates as PSO. The power of ACR and associated complication rate are both expected to improve with greater experience.

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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.

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