Preoperative Planning for Pedicle Subtraction Osteotomy: Does Pelvic Tilt Matter?

Virginie Lafage; Benjamin Blondel; Justin S Smith; Oheneba Boachie-Adjei; Richard A Hostin; Douglas Burton; Gregory Mundis; Eric Klineberg; Christopher Ames; Behrooz Akbarnia; Shay Bess; Frank Schwab; International Spine Study Group

doi:10.1016/j.jspd.2014.05.006

Preoperative Planning for Pedicle Subtraction Osteotomy: Does Pelvic Tilt Matter?

Spine Deform. 2014 Sep;2(5):358-366. doi: 10.1016/j.jspd.2014.05.006. Epub 2014 Aug 27.

Affiliations

¹ Spine Division, NYU Hospital for Joint Diseases, 306 E 15th Street, New York, NY 10003, USA. Electronic address: virginie.lafage@gmail.com.
² Spine Division, NYU Hospital for Joint Diseases, 306 E 15th Street, New York, NY 10003, USA; Universite Aix-Marseille, Marseille, 3 Place Victor Hugo, 13331 Marseille Cédex 3, France.
³ Neurological Surgery, University of Virginia, 1215 Lee Street, Charlottesville, VA 22903, USA.
⁴ Orthopedic Surgery, Hospital for Special Surgery, 535 E 70th St, New York, NY 10021, USA.
⁵ Orthopedic Surgery, Baylor Scoliosis Center, 4708 Alliance Blvd #800, Plano, TX 75093, USA.
⁶ Department of Orthopedic Surgery, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, USA.
⁷ San Diego Center for Spinal Disorders, 4130 La Jolla Village Dr, La Jolla, CA 92037, USA.
⁸ Department of Orthopedic Surgery, University of California, Davis Medical Center, 2315 Stockton Blvd, Sacramento, CA 95817, USA.
⁹ Department of Neurological Surgery, University of California San Francisco, 505 Parnassus Ave, San Francisco, CA 94143, USA.
¹⁰ Orthopedic Center, Rocky Mountain Hospital for Children, 1719 E 19th Ave, Denver, CO 80218, USA.
¹¹ Spine Division, NYU Hospital for Joint Diseases, 306 E 15th Street, New York, NY 10003, USA.

PMID: 27927333
DOI: 10.1016/j.jspd.2014.05.006

Abstract

Study design: Multicenter, retrospective radiographic analysis.

Objectives: To evaluate the impact that preoperative spinopelvic parameters have on postoperative sagittal vertical axis (SVA). The researchers hypothesized that patients with a large preoperative pelvic tilt (PT) would require more extensive lumbar pedicle subtraction osteotomy (LPSO) procedures to reestablish anatomic postoperative SVA than patients with normal preoperative PT.

Summary of background data: Restoration of anatomic sagittal spinal alignment has been demonstrated to improve clinical outcomes. However, the degree to which spinopelvic parameters contribute to sagittal spinal malalignment is poorly understood.

Methods: Multicenter, retrospective analysis of 183 consecutively enrolled adult spinal deformity patients treated with LPSO procedures for correction of sagittal malalignment. Preoperative and postoperative freestanding full-length sagittal X-rays were analyzed for regional curves, pelvic parameters, and global alignment. Only patients with a preoperative SVA greater than 10 cm and a postoperative SVA less than 5 cm were retained for analysis. Patients were divided into 2 groups according to preoperative PT (low PT, less than 30°; and high PT, ≥30°). Independent t test analysis was used to determine differences in correction required to achieve postoperative SVA less than 5 cm.

Results: A total of 55 patients were identified for analysis. Low PT (n = 30) had lower preoperative PT than high PT (n = 25; 25° vs. 42°, respectively; p < .001). Analysis of the osteotomy performed demonstrated that the high PT group required a larger osteotomy resection (30° vs. 23°; p = .039) and a larger correction of lumbar lordosis (-43° vs. -31°; p = .006) to achieve an acceptable postoperative SVA (less than 5 cm).

Conclusions: This study demonstrates that patients with high PT in conjunction with sagittal spinal malalignment require larger lumbar osteotomy procedures, including a greater osteotomy resection and larger lumbar lordosis correction, to obtain a satisfactory postoperative SVA. Surgeons performing LPSO procedures must evaluate preoperative spinopelvic parameters, including PT, to avoid undercorrection and residual deformity after complex sagittal realignment procedures.

Keywords: Osteotomy; Pelvic tilt; Preoperative planning; Radiographic outcomes; Sagittal malalignment.