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Clinical Trial
. 2023 Aug;165(8):2121-2129.
doi: 10.1007/s00701-023-05693-5. Epub 2023 Jul 5.

Is the presence of foraminal stenosis associated with outcome in lumbar spinal stenosis patients treated with posterior microsurgical decompression

Jørn Aaen  1   2 , Hasan Banitalebi  3   4 , Ivar Magne Austevoll  5   6 , Christian Hellum  7 , Kjersti Storheim  8 , Tor Åge Myklebust  9 , Masoud Anvar  10 , Clemens Weber  11   12 , Tore Solberg  13   14 , Oliver Grundnes  15 , Helena Brisby  16   17 , Kari Indrekvam  5   6 , Erland Hermansen  18   5   6
Affiliations
Clinical Trial

Is the presence of foraminal stenosis associated with outcome in lumbar spinal stenosis patients treated with posterior microsurgical decompression

Jørn Aaen et al. Acta Neurochir (Wien). 2023 Aug.

Abstract

Background: We aim to investigate associations between preoperative radiological findings of lumbar foraminal stenosis with clinical outcomes after posterior microsurgical decompression in patients with predominantly central lumbar spinal stenosis (LSS).

Methods: The study was an additional analysis in the NORDSTEN Spinal Stenosis Trial. In total, 230 men and 207 women (mean age 66.8 (SD 8.3)) were included. All patients underwent an MRI including T1- and T2-weighted sequences. Grade of foraminal stenosis was dichotomized into none to moderate (0-1) and severe (2-3) category using Lee's classification system. The Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), and numeric rating scale (NRS) for back and leg pain were collected at baseline and at 2-year follow-up. Primary outcome was a reduction of 30% or more on the ODI score. Secondary outcomes included the mean improvement on the ODI, ZCQ, and NRS scores. We performed multivariable regression analyses with the radiological variates foraminal stenosis, Pfirrmann grade, Schizas score, dural sac cross-sectional area, and the possible plausible confounders: patients' gender, age, smoking status, and BMI.

Results: The cohort of 437 patients presented a high degree of degenerative changes at baseline. Of 414 patients with adequate imaging of potential foraminal stenosis, 402 were labeled in the none to moderate category and 12 in the severe category. Of the patients with none to moderate foraminal stenosis, 71% achieved at least 30% improvement in ODI. Among the patients with severe foraminal stenosis, 36% achieved at least 30% improvement in ODI. A significant association between severe foraminal stenosis and less chance of reaching the target of 30% improvement in the ODI score after surgery was detected: OR 0.22 (95% CI 0.06, 0.83), p=0.03. When investigating outcome as continuous variables, a similar association between severe foraminal stenosis and less improved ODI with a mean difference of 9.28 points (95%CI 0.47, 18.09; p=0.04) was found. Significant association between severe foraminal stenosis and less improved NRS pain in the lumbar region was also detected with a mean difference of 1.89 (95% CI 0.30, 3.49; p=0.02). No significant association was suggested between severe foraminal stenosis and ZCQ or NRS leg pain.

Conclusion: In patients operated with posterior microsurgical decompression for LSS, a preoperative severe lumbar foraminal stenosis was associated with higher proportion of patients with less than 30% improvement in ODI.

Trial registration: The study is registered at ClinicalTrials.gov (22.11.2013) under the identifier NCT02007083.

Keywords: Disk degeneration; Foraminal stenosis; LSS; NORDSTEN; Outcome.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Flow chart of the NORDSTEN-SST investigating influence of foraminal stenosis. DST, Degenerative Spondylolisthesis Trial; SST, Spinal Stenosis Trial
Fig. 2
Fig. 2
Baseline data. Illustration of the percentage of patients with worst dichotomy score (orange) in each radiological classification system
See this image and copyright information in PMC

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References

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