Is Preoperative Sarcopenia a Risk Factor for Loss of Cervical Lordosis Following Laminoplasty?

Study Design: Retrospective cohort study (2014–2022). Objective: This study aimed to assess the impact of sternocleidomastoid (SCM) muscle sarcopenia on preoperative and postoperative cervical alignment following laminoplasty. Summary of Background Data: Postlaminoplasty loss of lordosis can lead to poor outcomes, but its risk factors, including SCM sarcopenia, are not fully understood. Materials and Methods: After approval of an Institutional Review Board, we retrospectively identified patients who underwent elective primary cervical laminoplasty for myelopathy (2014–2022). Revision, trauma, infection, or malignancy cases were excluded. Sarcopenia at C5-C6 was quantified on preoperative MRI by measuring the BMI-adjusted SCM cross-sectional area (CSA). The Goutallier grade (GG) for fatty infiltration was recorded at the same level. Patients were stratified into high or low SCM groups based on the 50th percentile for BMI-adjusted SCM CSA, and by zero versus nonzero SCM GG. Preoperative and postoperative cervical alignment (C2-C7 Cobb angle, C2-C7 sagittal vertical axis, C2 tilt, C2 slope) and patient-reported outcomes were compared between groups. Bivariate analyses were employed as appropriate for continuous and discrete data. Results: Fifty-six patients were included. High CSA patients were younger (59.7 vs. 66.0 yr, P =0.029), predominantly male (82.1% vs. 42.9%, P =0.006), and had lower CCI (2.54 vs. 3.75; P =0.002). When stratified by BMI-adjusted SCM CSA and by GG, there were no significant differences in postoperative sagittal alignment or surgical outcomes. Patients with higher fatty infiltration (nonzero GG) reported significantly worse Neck Disability Index (NDI) scores at all timepoints ( P <0.05). Conclusions: Neither SCM muscle size nor fatty infiltration was associated with changes in postoperative sagittal alignment or surgical outcomes following laminoplasty. However, patients undergoing laminoplasty with higher Goutallier fatty infiltration scores had worse preoperative and postoperative NDI scores. This suggests that muscle quality, rather than muscle bulk or its effect on alignment, may be a relevant determinant of functional outcomes. However, these findings were observed in a limited range of GGs with an overall mild severity. Thus, this topic needs further exploration in patients with more severe sarcopenia. Level of Evidence: Level III.