Spine - 2026-03-15 - Journal Article
Mild Changes in Sternocleidomastoid Muscle Quality Predict Pseudarthrosis After Anterior Cervical Discectomy and Fusion.
Dalton J, Oris RJ, Ezeonu T, Narayanan R, Tomlak A, Heard JC, Lee YA, Farooqi AS, Berthiaume E, Kazantsev M, Hamid A, Khanna A, Mangan JJ, Canseco JA, Kaye ID, Kurd MF, Hilibrand AS, Vaccaro AR, Schroeder GD, Kepler C
Topics
Key Takeaway
Goutallier grade fatty infiltration of the sternocleidomastoid independently increases odds of pseudarthrosis after ACDF by 3.46-fold (OR 3.46, P=0.009), with a 33.7% overall pseudarthrosis rate in this cohort.
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Summary
This study examined whether preoperative SCM cross-sectional area and Goutallier fatty infiltration grade at C5-C6 predict pseudarthrosis and PROMs at 1 year after 1-to-4 level ACDF in 205 patients. Pseudarthrosis occurred in 33.7% of patients; higher Goutallier grade independently predicted pseudarthrosis (OR 3.46, P=0.009) while normalized SCM CSA did not. Greater SCM fatty infiltration correlated with improved PCS scores (P=0.023), but no other PROM differences were identified between pseudarthrosis and fusion groups.
Key Limitation
The 33.7% pseudarthrosis rate substantially exceeds the established benchmark of 1.8% nonunion in the literature, suggesting either a highly selected high-risk cohort or systematic diagnostic criteria differences that limit generalizability.
Original Abstract
STUDY DESIGN
Retrospective cohort.
OBJECTIVE
To investigate the impact of cervical paraspinal muscle mass and quality on the rate of pseudarthrosis and patient-reported outcome measures (PROMs) after anterior cervical discectomy and fusion (ACDF).
SUMMARY OF BACKGROUND DATA
Poor muscle quality has been shown to correlate with inferior outcomes in spine surgery. However, few studies have investigated the impact of paraspinal sarcopenia on pseudoarthrosis following cervical spine surgery.
MATERIALS AND METHODS
Adult patients who underwent primary, elective one-to-four level ACDF with preoperative magnetic resonance imaging (MRI) and postoperative radiographs were included. MRIs were reviewed to assess sternocleidomastoid (SCM) cross-sectional area (CSA) and Goutallier grade at the C5-C6 disc space. Pseudarthrosis was diagnosed on 1-year postoperative flexion-extension radiographs as <1 mm of interspinous motion between each instrumented level. Patient demographic and surgical variables and 1-year patient-reported outcome measures (PROMs) were compared between those with and without pseudoarthrosis on bivariate and multivariate analyses.
RESULTS
A total of 205 patients were included (33.7% with pseudoarthrosis). The pseudoarthrosis group had a higher percentage of patients with 4-level (7.25% vs . 1.47%) and 3-level (30.4% vs . 17.6%, P =0.01) ACDF. The groups were similar in terms of demographics, surgical variables, and SCM area normalized to BMI. After controlling for the SCM CSA group, age, sex, BMI, and number of levels fused, a higher Goutallier grade independently increased the odds of pseudoarthrosis [odds ratio (OR): 3.46, P =0.009]. Patients with greater SCM fatty infiltration experienced greater improvement in PCS scores ( P =0.023), but there were no other differences in PROM scores between groups.
CONCLUSION
Although this analysis did not show an association between SCM muscle size and pseudoarthrosis, even mild fatty infiltration appears to be independently predictive of pseudoarthrosis. In contrast, PROMs were not associated with SCM size or fatty infiltration. Further work is needed to confirm these findings and explore their clinical implications.