Lower Hounsfield Units and Severe Multifidus Sarcopenia Are Independent Predictors of Increased Risk for Proximal Junctional Kyphosis and Failure Following Thoracolumbar Fusion
Study Design. Retrospective cohort study. Objective. The purpose of the present study was to assess the impact of sarcopenia on the development of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) following thoracolumbar spine fusion surgery using opportunistic evaluation of paraspinal fatty degeneration on preoperative magnetic resonance imaging. Summary of Background Data. While paraspinal sarcopenia has been shown to have detrimental consequences following posterior cervicothoracic fusions, the impact of paraspinal sarcopenia on PJK and PJF following thoracolumbar spine fusion surgery remains unknown. Materials and Methods. We performed a retrospective review of patients who underwent posterior spine fusion surgery that extended caudally to the pelvis and terminated cranially between T10 and L2 between 2010 and 2017. The cohort was divided into three groups: (1) patients without PJK or PJF, (2) patients with PJK but no PJF, and (3) patients with PJF. Univariate and multivariate analyses were performed to determine risk factors for the development of proximal junctional complications. Results. We identified 150 patients for inclusion in this study. Mean Hounsfield Units at the upper instrumented vertebra (UIV) was 148.3±34.5 in the cohort of patients without PJK or PJF, which was substantially higher than values recorded in the PJK (117.8±41.9) and PJF (118.8±41.8) subgroups ( P <0.001). Severe multifidus sarcopenia was identified at a much higher rate in the subgroups of patients who developed PJK (76.0%) and PJF (78.9%) than in the subgroup of patients who developed neither PJK nor PJF (34.0%; P <0.001). Multivariate analysis demonstrated both low HU at the UIV and moderate-severe multifidus sarcopenia to be risk factors for the development of PJK and PJF. Conclusion. The results of this study suggest severe paraspinal sarcopenia and diminished bone density at the UIV impart an increased risk of developing PJK and PJF, while markers of systemic frailty such as modified Frailty Index and Charlson Comorbidity Index are not associated with an increased risk of these complications. Level of Evidence. III.
Semispinalis Cervicis Sarcopenia is Associated With Worsening Cervical Sagittal Balance and Junctional Alignment Following Posterior Cervical Fusion for Myelopathy
Study Design: This was a retrospective cohort study. Objective: The present study is the first to investigate whether cervical paraspinal sarcopenia is associated with cervicothoracic sagittal alignment parameters after posterior cervical fusion (PCF). Summary of Background Data: Few studies have investigated the association between sarcopenia and postoperative outcomes after cervical spine surgery. Methods: We retrospectively reviewed patients undergoing PCF from C2–T2 at a single institution between the years 2017–2020. Two independent reviewers utilized axial cuts of T2-weighted magnetic resonance imaging sequences to perform Goutallier classification of the bilateral semispinalis cervicis (SSC) muscles. Cervical sagittal alignment parameters were compared between subgroups based upon severity of SSC sarcopenia. Results: We identified 61 patients for inclusion in this study, including 19 patients with mild SSC sarcopenia and 42 patients with moderate or severe SSC sarcopenia. The moderate-severe sarcopenia subgroup demonstrated a significantly larger change in C2–C7 sagittal vertical axis (+6.8 mm) from the 3-month to 1-year postoperative follow-up in comparison to the mild sarcopenia subgroup (−2.0 mm; P=0.02). The subgroup of patients with moderate-severe sarcopenia also demonstrated an increase in T1–T4 kyphosis (10.9–14.2, P=0.007), T1 slope (28.2–32.4, P=0.003), and C2 slope (24.1–27.3, P=0.05) from 3-month to 1-year postoperatively and a significant decrease in C1-occiput distance (6.3–4.1, P=0.002) during this same interval. Conclusions: In a uniform cohort of patients undergoing PCF from C2–T2, SSC sarcopenia was associated with worsening cervicothoracic alignment from 3-month to 1-year postoperatively.
Multifidus Sarcopenia Is Associated With Worse Patient-reported Outcomes Following Posterior Cervical Decompression and Fusion
Study Design. Retrospective cohort study. Objective. The present study is the first to assess the impact of paraspinal sarcopenia on patient-reported outcome measures (PROMs) following posterior cervical decompression and fusion (PCDF). Summary of Background Data. While the impact of sarcopenia on PROMs following lumbar spine surgery is well-established, the impact of sarcopenia on PROMs following PCDF has not been investigated. Materials and Methods. We performed a retrospective review of patients undergoing PCDF from C2 to T2 at a single institution between the years 2017 and 2020. Two independent reviewers who were blinded to the clinical outcome scores utilized axial cuts of T2-weighted magnetic resonance imaging sequences to assess fatty infiltration of the bilateral multifidus muscles at the C5–C6 level and classify patients according to the Fuchs Modification of the Goutalier grading system. PROMs were then compared between subgroups. Results. We identified 99 patients for inclusion in this study, including 28 patients with mild sarcopenia, 45 patients with moderate sarcopenia, and 26 patients with severe sarcopenia. There was no difference in any preoperative PROM between the subgroups. Mean postoperative Neck Disability Index scores were lower in the mild and moderate sarcopenia subgroups (12.8 and 13.4, respectively) than in the severe sarcopenia subgroup (21.0, P <0.001). A higher percentage of patients with severe multifidus sarcopenia reported postoperative worsening of their Neck Disability Index (10 patients, 38.5%; P =0.003), Visual Analog Scale Neck scores (7 patients, 26.9%; P =0.02), Patient-Reported Outcome Measurement Information System Physical Component Scores (10 patients, 38.5%; P =0.02), and Patient-Reported Outcome Measurement Information System Mental Component Scores (14 patients, 53.8%; P =0.02). Conclusion. Patients with more severe paraspinal sarcopenia demonstrate less improvement in neck disability and physical function postoperatively and are substantially more likely to report worsening PROMs postoperatively. Level of Evidence. 3.
Intraoperative Fracture of a Dual Modular Delta Ceramic Femoral Head During Total Hip Arthroplasty
Case: A 39-year-old man with cerebral palsy and hip dysplasia status post right Chiari osteotomy presented with right hip osteoarthritis in consultation for total hip arthroplasty (THA). During THA, a Delta ceramic head was misaligned on the taper, but this was obscured by an overlying dual modular polyethylene shell. When we attempted to tap the head onto the taper, fracture occurred requiring revision to a cobalt-chromium head due to slight taper damage. Conclusion: To our knowledge, this is the first reported case of intraoperative fracture of a BIOLOX Delta dual modular head.