Neither Sagittal Nor Spinopelvic Malalignment Determinative?

New work from a team of Canadian researchers has determined that neither sagittal nor spinopelvic malalignment vastly affect patient-reported outcomes in patients with degenerative lumbar spondylolisthesis. Their work, “Preoperative Patient-reported Outcomes are not Associated With Sagittal and Spinopelvic Alignment in Degenerative Lumbar Spondylolisthesis,” is published in the August 15, 2022 edition of Spine.

Dr. Christopher Bailey, co-author and associate professor in surgery at the London Health Sciences Center in Ontario explained the background of this very intriguing study to OTW. “To our understanding the correlation between preoperative patient reported outcomes with sagittal and spinopelvic alignment has not been studied in the specific population of lumbar degenerative spondylolisthesis, although this topic has been investigated in postoperative patients and other spinal diagnoses.”

“Our study group is interested in the treatment, particularly surgical, of lumbar degenerative spondylolisthesis, and those factors that may influence the outcomes of that treatment. To that end, sagittal and spinopelvic alignment is a radiographic factor that may play an important role. This study is looking at the importance of that factor in preoperative outcomes, while future publications will examine the association between these radiographic parameters and postoperative patient reported outcomes.”

The researchers enrolled patients in the Canadian Spine Outcomes Research Network prospective degenerative lumbar spondylolisthesis study at seven centers between January 2015 and May 2018.

In all, the team assessed 320 patients (61% female) with a mean age of 66.1 years. Mean standard deviations and preoperative patient reported outcomes were:

• numeric rating scale leg pain 7.4 (2.1),
• numeric rating scale back pain 7.1 (2.0), and
• Oswestry Disability Index 5 (14.5).

Preoperative radiographic parameters included:

• sagittal vertical axis 27.1 (33.4) mm,
• lumbar lordosis 45.7 (13.4°),
• pelvic incidence 6 (11.9), and
• pelvic incidence-lumbar lordosis 11.8 (14.0°).

The team found “weak but statistically significant correlations” between leg pain and pelvic tilt and pelvic incidence, and T9 spinopelvic inclination with back pain.

They found “no significant differences among the three groups stratified by pelvic incidence-lumbar lordosis and pelvic tilt. No significant differences in PROs were observed between patients with sagittal vertical axis <50 mm compared to those with sagittal vertical axis ≥50 mm.”

“Our most important finding,” explained Dr. Bailey to OTW, “is that radiographic sagittal and spinopelvic alignment do not appear to significantly influence preoperative patient reported outcome (PRO) measures for patients with degenerative lumbar spondylolisthesis. Importantly, all the enrolled patients had concurrent spinal stenosis and we suspect that the lack of correlation may be due to the influence that the symptoms of spinal stenosis have on patient reported outcomes relative to the influence that may be resulting from sagittal malalignment.”

“The degree of the sagittal malalignment in our patient cohort is relatively small compared to other diagnosis such as adult deformity, for which other publications have demonstrated positive correlations. We however recognize that pre- and postoperative sagittal and spinopelvic alignment may be an important factor in postoperative outcome and should be further evaluated. Postoperatively, the spinal stenosis has been decompressed and perhaps those associated symptoms will no longer overshadow those associated with sagittal and spinopelvic alignment.”