Research highlights the importance of spinal alignment in all, not just deformity, lumbar fusions


alignmentThe results of a report looking at the rates of spinopelvic malalignment in nearly 600 patients show that malalignment is common both before and after short-segment degenerative fusions. These findings are detailed in the first peer-reviewed publication from the NuVasive-sponsored multicentre integrated global alignment (iGA) study, currently in press in Spine.

This initial study evaluated the preoperative prevalence and incidence of postoperative spinopelvic malalignment in patients who underwent one- or two-level lumbar fusions for degenerative (non-deformity) indications.

Spinopelvic malalignment (defined as pelvic incidence (PI) minus lumbar lordosis (LL) greater than or equal to 10°) following lumbar fusion has been shown to be associated with lower postoperative health-related quality of life and elevated risk of adjacent segment failure; however, the incidence of this in short-segment degenerative lumbar fusions from a large sample of patients had been previously unreported.

The measurements of the nearly 600 patients involved in the study were retrospectively acquired. Researchers measured lateral preoperative and postoperative lumbar radiographs of one- or two-level lumbar fusion patients using the iGA platform (NuVasive). The study was conducted at 18 institutions with 24 treating investigators in the USA. Patients were grouped as either aligned (PI-LL<10°) or malaligned (PI-LL≥10°) both pre- and postoperatively.

Malalignment was found to be common. Preoperatively, 173 (30%) patients undergoing one- or two-level lumbar fusion surgery for degenerative conditions exhibited malalignment and postoperatively, 161 (28%) patients were malaligned. These relatively high rates of pre- and postoperative malalignment, even in degenerative cases, demonstrate this is not a deformity-only problem and alignment should be measured in all cases.

“This study further demonstrates that incorporating alignment measurements using iGA into our surgical planning directly translates to our patients and the clinical benefits/outcomes we know are influenced by achieving global spinal alignment,” says Jean-Christophe Leveque (Neuroscience Institute, Virginia Mason Hospital and Medical Center, Seattle, USA). “Alignment in deformity procedures has been relevant for years, but this is the first multicentre study to show just how common malalignment is both before and after short-segment, degenerative fusions. We need to shift our mind set as spine surgeons, recognise these results from simple degenerative cases and start measuring spinopelvic parameters in all of our lumbar fusion cases, especially those that involve L4 through S1.”

The conclusion of the study was that alignment preservation and restoration considerations should be incorporated into the decision-making of all lumbar spinal fusions. Prior to this research, spinal alignment considerations were only thought necessary for spinal deformity cases.

The published results of this study and two additional iGA studies evaluating 1) changes between preoperative standing and intraoperative recumbent alignment and 2) the role of pre- and intraoperative alignment planning on surgical execution and outcomes, will be on the podium at the North American Spine Society (NASS) Annual Meeting in September.


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