Pinter, Zachariah W.

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.

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.

OBJECTIVE Patients with ankylosing spinal disorders (ASDs), including ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH), have been shown to experience significantly increased rates of postoperative complications. Despite this, very few risk stratification tools have been validated for this population. As such, the purpose of this study was to identify predictors of adverse events and mortality in ASD patients undergoing surgery for 3-column fractures. METHODS All adult patients with a documented history of AS or DISH who underwent surgery for a traumatic 3-column fracture between 2000 and 2020 were identified. Perioperative variables, including comorbidities, time to diagnosis, and number of fused segments, were collected. Three instruments, including the Charlson Comorbidity Index (CCI), modified frailty index (mFI), and Injury Severity Score (ISS), were computed for each patient. The primary outcomes of interest included 1-year mortality, as well as postoperative complications. RESULTS A total of 108 patients were included, with a mean ± SD age of 73 ± 11 years. Of these, 41 (38%) experienced at least 1 postoperative complication and 22 (20.4%) died within 12 months after surgery. When the authors controlled for potential known confounders, the CCI score was significantly associated with postoperative adverse events (OR 1.20, 95% CI 1.00–1.42, p = 0.045) and trended toward significance for mortality (OR 1.19, 95% CI 0.97–1.45, p = 0.098). In contrast, mFI score and ISS were not significantly predictive of either outcome. CONCLUSIONS Complications in spine trauma patients with ASD may be driven by comorbidity burden rather than operative or injury-related factors. The CCI may be a valuable tool for the evaluation of this unique population.

OBJECTIVE The aim of this study was to analyze risk factors and avoidance techniques for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in the upper thoracic spine with an emphasis on bone mineral density (BMD) as estimated by Hounsfield units (HU). METHODS A retrospective chart review identified patients at least 50 years of age who underwent instrumented fusion extending from the pelvis to an upper instrumented vertebra (UIV) between T1 and T6 and had a preoperative CT, pre- and postoperative radiographs, and a minimum follow-up of 12 months. HU were measured in the UIV, the vertebral body cephalad to the UIV (UIV+1), and the L3 and L4 vertebral bodies. Numerous perioperative variables were collected, including basic demographics, smoking and steroid use, preoperative osteoporosis treatment, multiple frailty indices, use of a proximal junctional tether, UIV soft landing, preoperative dual-energy x-ray absorptiometry, spinopelvic parameters, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, lumbar lordosis distribution, and postoperative spinopelvic parameters compared with age-adjusted normal values. RESULTS Eighty-one patients were included in the study (21 men and 60 women) with a mean (SD) age of 66 years (6.9 years), BMI of 29 (5.5), and follow-up of 38 months (25 months). Spinal fusion constructs at the time of surgery extended from the pelvis to a UIV of T1 (5%), T2 (15%), T3 (25%), T4 (33%), T5 (21%), and T6 (1%). Twenty-seven patients (33%) developed PJK and/or PJF; 21 (26%) had PJK and 15 (19%) had PJF. Variables associated with PJK/PJF with p < 0.05 were included in the multivariable analysis, including HU at the UIV/UIV+1, HU at L3/L4, DXA femoral neck T-score, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, and postoperative lumbar lordosis distribution. Multivariable analysis (area under the curve = 0.77) demonstrated HU at the UIV/UIV+1 to be the only independent predictor of PJK and PJF with an OR of 0.96 (p = 0.005). Patients with < 147 HU (n = 27), 147–195 HU (n = 27), and > 195 HU (n = 27) at the UIV/UIV+1 had PJK/PJF rates of 59%, 33%, and 7%, respectively. CONCLUSIONS In patients with upper thoracic–to-pelvis spinal reconstruction, lower HU at the UIV and UIV+1 were independently associated with PJK and PJF, with an optimal cutoff of 159 HU that maximizes sensitivity and specificity.

Study Design: Retrospective cohort study. Objective: The purposes of this study were to determine the rate of improvement of significant preoperative weakness, identify risk factors for failure to improve, and characterize the motor recovery of individual motor groups. Summary of Background Data: While neck and arm pain reliably improve following anterior cervical discectomy and fusion (ACDF), the frequency and magnitude of motor recovery following ACDF remain unclear. Methods: We performed a retrospective review of patients undergoing 1–4-level ACDF at a single institution between September 2015 and June 2016. Patients were subdivided into 2 groups based upon the presence or absence of significant preoperative weakness, which was defined as a motor grade <4 in any single upper extremity muscle group. Clinical notes were reviewed to determine affected muscle groups, rates of motor recovery, and risk factors for failure to improve. Results: We identified 618 patients for inclusion. Significant preoperative upper extremity weakness was present in 27 patients (4.4%). Postoperatively, 19 of the affected patients (70.3%) experienced complete strength recovery, and 5 patients (18.5%) experienced an improvement in muscle strength to a motor grade ≥4. The rate of motor recovery postoperatively was 85.7% in the triceps, 83.3% in the finger flexors, 83.3% in the hand intrinsics, 50.0% in the biceps, and 25.0% in the deltoids. Risk factors for failure to experience significant motor improvement were the presence of myelomalacia (odds ratio: 28.9, P<0.01) and the performance of >2 levels of ACDF (odds ratio: 10.1, P<0.01). Conclusions: Patients with substantial preoperative upper extremity weakness can expect high rates of motor recovery following ACDF, though patients with deltoid weakness, myelomalacia, and >2 levels of ACDF are less likely to experience significant motor improvement.

Study Design: This was a multicenter retrospective cohort study. Objective: The purpose of this study was to compare the surgical and radiographic outcomes of patients undergoing posterior cervical fusion (PCF) with constructs extending from C2 to T2 to patients with constructs extending from C3 to T1. Summary of Background Data: Limited evidence exists regarding the appropriate level of proximal and distal extension of PCF constructs. Methods: A multicenter retrospective cohort study of patients who underwent PCF between 2012 and 2020 was performed. Surgical and radiographic outcomes were compared between those who had C3–T1 or C2–T2 constructs. Results: A total of 155 patients were included in the study (C2–T2: 106 patients, C3–T1: 49 patients). There were no significant differences in demographics or preoperative symptoms between cohorts. Fusion rates were significantly higher in the C2–T2 (93%) than the C3–T1 (80%, P=0.040) cohort. When comparing the C2–T2 to the C3–T1 cohort, the C3–T1 cohort had a significantly greater rate of proximal junctional failure (2% vs. 10%, P=0.006), distal junctional failure (1% vs. 20%, P<0.001) and distal screw loosening (4% vs. 15%, P=0.02). Although ∆C2–C7 sagittal vertical axis increased significantly in both cohorts (C2–T2: 6.2 mm, P=0.04; C3–T1: 8.4 mm, P<0.001), correction did not significantly differ between groups (P=0.32). The C3–T1 cohort had a significantly greater increase in ∆C2 slope (8.0 vs. 3.1 degrees, P=0.03) and ∆C0–C2 Cobb angle (6.4 vs. 1.2 degrees, P=0.04). Conclusion: In patients undergoing PCF, a C2–T2 construct demonstrated lower rates of pseudarthrosis, distal junctional failure, proximal junctional failure, and compensatory upper cervical hyperextension compared with a C3–T1 construct.

Transdiscal screw fixation through the Boachie screw technique at the lumbosacral junction is a well-accepted procedure in the treatment of high-grade spondylolisthesis. This technique allows for partial reduction of the spondylolisthesis, decompression of the neural elements, and reliable posterior lumbosacral fixation. When performed properly, this procedure produces reliable results and high rates of arthrodesis with relief of preoperative neurological symptoms.

Study Design Retrospective cohort study Objective Substantial variability in both the measurement and classification of subsidence limits the strength of conclusions that can be drawn from previous studies. The purpose of this study was to precisely characterize patterns of cervical cage subsidence utilizing computed tomography (CT) scans, determine risk factors for cervical cage subsidence, and investigate the impact of subsidence on pseudarthrosis rates. Methods We performed a retrospective review of patients who underwent one- to three-levels of anterior cervical discectomy and fusion (ACDF) utilizing titanium interbodies with anterior plating between the years 2018 and 2020. Subsidence measurements were performed by two independent reviewers on CT scans obtained 6 months postoperatively. Subsidence was then classified as mild if subsidence into the inferior and superior endplate were both ≤2 mm, moderate if the worst subsidence into the inferior or superior endplate was between 2 to 4 mm, or severe if the worst subsidence into the inferior or superior endplate was ≥4 mm. Results A total of 51 patients (100 levels) were included in this study. A total of 48 levels demonstrated mild subsidence (≤2 mm), 38 demonstrated moderate subsidence (2-4 mm), and 14 demonstrated severe subsidence (≥4 mm). Risk factors for severe subsidence included male gender, multilevel constructs, greater mean vertebral height loss, increased cage height, lower Taillard index, and lower screw tip to vertebral body height ratio. Severe subsidence was not associated with an increased rate of pseudarthrosis. Conclusion Following ACDF with titanium cervical cages, subsidence is an anticipated postoperative occurrence and is not associated with an increased risk of pseudarthrosis.

Abstract BACKGROUND Low bone mineral density (BMD) on dual energy x-ray absorptiometry (DXA) is likely a risk factor for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). However, prior instrumentation and degenerative changes can preclude a lumbar BMD measurement. Hounsfield units (HU) represent an alternative method to estimate BMD via targeted measurements at the intended operative levels. OBJECTIVE To determine if patients with lower HU at the upper instrumented vertebrae (UIV) and vertebral body superior to the UIV (UIV + 1) are at greater risk for PJK and PJF. METHODS A retrospective chart review identified patients at least 50 yr of age who underwent instrumented lumbar fusion with pelvic fixation, a UIV from T10 to L2, and a preoperative computed tomography (CT) encompassing the UIV. HU were measured at the UIV, UIV + 1, and the L3-L4 vertebral bodies. RESULTS A total of 150 patients (80 women and 70 men) were included with an average age of 66 yr and average follow-up of 32 mo. Multivariable logistic regression analysis with an area under the curve (AUC) of 0.89 demonstrated HU at the UIV/UIV + 1 as the only independent predictor of PJK/PJF with an odds ratio of 0.94 ( P -value = .031) for a change in a single HU. Patients with HU at UIV/UIV + 1 of <110 (n = 35), 110 to 160 (n = 73), and >160 (n = 42) had a rate of PJK/PJF of 63%, 27%, and 12%, respectively ( P -value < .001). CONCLUSION Patients with lower HU at the UIV and UIV + 1 were significantly associated with PJK and PJF, with an optimal cutoff of 122 HU that maximizes sensitivity and specificity.