Nassr, Ahmad

OBJECTIVE The purpose of this study was to determine the effect of osteoporosis medications on opportunistic CT-based Hounsfield units (HU). METHODS Spine and nonspine surgery patients were retrospectively identified who had been treated with romosozumab for 3 to 12 months, teriparatide for 3 to 12 months, teriparatide for > 12 months, denosumab for > 12 months, or alendronate for > 12 months. HU were measured in the L1–4 vertebral bodies. One-way ANOVA was used to compare the mean change in HU among the five treatment regimens. RESULTS In total, 318 patients (70% women) were included, with a mean age of 69 years and mean BMI of 27 kg/m 2 . There was a significant difference in mean HU improvement (p < 0.001) following treatment with romosozumab for 3 to 12 months (n = 32), teriparatide for 3 to 12 months (n = 30), teriparatide for > 12 months (n = 44), denosumab for > 12 months (n = 123), and alendronate for > 12 months (n = 100). Treatment with romosozumab for a mean of 10.5 months significantly increased the mean HU by 26%, from a baseline of 85 to 107 (p = 0.012). Patients treated with teriparatide for > 12 months (mean 23 months) experienced a mean HU improvement of 25%, from 106 to 132 (p = 0.039). Compared with the mean baseline HU, there was no significant difference after treatment with teriparatide for 3 to 12 months (110 to 119, p = 0.48), denosumab for > 12 months (105 to 107, p = 0.68), or alendronate for > 12 months (111 to 113, p = 0.80). CONCLUSIONS Patients treated with romosozumab for a mean of 10.5 months and teriparatide for a mean of 23 months experienced improved spinal bone mineral density as estimated by CT-based opportunistic HU. Given the shorter duration of effective treatment, romosozumab may be the preferred medication for optimization of osteoporotic patients in preparation for elective spine fusion surgery.

OBJECTIVE The aims of this study were to 1) define the incidence of transforaminal lumbar interbody fusion (TLIF) interbody subsidence; 2) determine the relative importance of preoperative and intraoperative patient- and instrumentation-specific risk factors predictive of postoperative subsidence using CT-based assessment; and 3) determine the impact of TLIF subsidence on postoperative complications and fusion rates. METHODS All adult patients who underwent one- or two-level TLIF for lumbar degenerative conditions at a multi-institutional academic center between 2017 and 2019 were retrospectively identified. Patients with traumatic injury, infection, malignancy, previous fusion at the index level, combined anterior-posterior procedures, surgery with greater than two TLIF levels, or incomplete follow-up were excluded. Interbody subsidence at the superior and inferior endplates of each TLIF level was directly measured on the endplate-facing surface of both coronal and sagittal CT scans obtained greater than 6 months postoperatively. Patients were grouped based on the maximum subsidence at each operative level classified as mild, moderate, or severe based on previously documented < 2-mm, 2- to 4-mm, and ≥ 4-mm thresholds, respectively. Univariate and regression analyses compared patient demographics, medical comorbidities, preoperative bone quality, surgical factors including interbody cage parameters, and fusion and complication rates across subsidence groups. RESULTS A total of 67 patients with 85 unique fusion levels met the inclusion and exclusion criteria. Overall, 28% of levels exhibited moderate subsidence and 35% showed severe subsidence after TLIF with no significant difference in the superior and inferior endplate subsidence. Moderate (≥ 2-mm) and severe (≥ 4-mm) subsidence were significantly associated with decreases in cage surface area and Taillard index as well as interbody cages with polyetheretherketone (PEEK) material and sawtooth surface geometry. Severe subsidence was also significantly associated with taller preoperative disc spaces, decreased vertebral Hounsfield units (HU), the absence of bone morphogenetic protein (BMP) use, and smooth cage surfaces. Regression analysis revealed decreases in Taillard index, cage surface area, and HU, and the absence of BMP use predicted subsidence. Severe subsidence was found to be a predictor of pseudarthrosis but was not significantly associated with revision surgery. CONCLUSIONS Patient-level risk factors for TLIF subsidence included decreased HU and increased preoperative disc height. Intraoperative risk factors for TLIF subsidence were decreased cage surface area, PEEK cage material, bullet cages, posterior cage positioning, smooth cage surfaces, and sawtooth surface designs. Severe subsidence predicted TLIF pseudarthrosis; however, the causality of this relationship remains unclear.

Importance The modified Japanese Orthopaedic Association (mJOA) scale is the most common scale used to represent outcomes of degenerative cervical myelopathy (DCM); however, it lacks consideration for neck pain scores and neglects the multidimensional aspect of recovery after surgery. Objective To use a global statistical approach that incorporates assessments of multiple outcomes to reassess the efficacy of riluzole in patients undergoing spinal surgery for DCM. Design, Setting, and Participants This was a secondary analysis of prespecified secondary end points within the Efficacy of Riluzole in Surgical Treatment for Cervical Spondylotic Myelopathy (CSM-PROTECT) trial, a multicenter, double-blind, phase 3 randomized clinical trial conducted from January 2012 to May 2017. Adult surgical patients with DCM with moderate to severe myelopathy (mJOA scale score of 8-14) were randomized to receive either riluzole or placebo. The present study was conducted from July to December 2023. Intervention Riluzole (50 mg twice daily) or placebo for a total of 6 weeks, including 2 weeks prior to surgery and 4 weeks following surgery. Main Outcomes and Measures The primary outcome measure was a difference in clinical improvement from baseline to 1-year follow-up, assessed using a global statistical test (GST). The 36-Item Short Form Health Survey Physical Component Score (SF-36 PCS), arm and neck pain numeric rating scale (NRS) scores, American Spinal Injury Association (ASIA) motor score, and Nurick grade were combined into a single summary statistic known as the global treatment effect (GTE). Results Overall, 290 patients (riluzole group, 141; placebo group, 149; mean [SD] age, 59 [10.1] years; 161 [56%] male) were included. Riluzole showed a significantly higher probability of global improvement compared with placebo at 1-year follow-up (GTE, 0.08; 95% CI, 0.00-0.16; P = .02). A similar favorable global response was seen at 35 days and 6 months (GTE for both, 0.07; 95% CI, −0.01 to 0.15; P = .04), although the results were not statistically significant. Riluzole-treated patients had at least a 54% likelihood of achieving better outcomes at 1 year compared with the placebo group. The ASIA motor score and neck and arm pain NRS combination at 1 year provided the best-fit parsimonious model for detecting a benefit of riluzole (GTE, 0.11; 95% CI, 0.02-0.16; P = .007). Conclusions and Relevance In this secondary analysis of the CSM-PROTECT trial using a global outcome technique, riluzole was associated with improved clinical outcomes in patients with DCM. The GST offered probability-based results capable of representing diverse outcome scales and should be considered in future studies assessing spine surgery outcomes.

Background: The comparative effectiveness of decompression plus lumbar facet arthroplasty versus decompression plus instrumented lumbar spinal fusion in patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis is unknown. Methods: In this randomized, controlled, Food and Drug Administration Investigational Device Exemption trial, we assigned patients who had single-level lumbar spinal stenosis and grade-I degenerative spondylolisthesis to undergo decompression plus lumbar facet arthroplasty (arthroplasty group) or decompression plus fusion (fusion group). The primary outcome was a predetermined composite clinical success score. Secondary outcomes included the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg pain, Zurich Claudication Questionnaire (ZCQ), Short Form (SF)-12, radiographic parameters, surgical variables, and complications. Results: A total of 321 adult patients were randomized in a 2:1 fashion, with 219 patients assigned to undergo facet arthroplasty and 102 patients assigned to undergo fusion. Of these, 113 patients (51.6%) in the arthroplasty group and 47 (46.1%) in the fusion group who had either reached 24 months of postoperative follow-up or were deemed early clinical failures were included in the primary outcome analysis. The arthroplasty group had a higher proportion of patients who achieved composite clinical success than did the fusion group (73.5% versus 25.5%; p < 0.001), equating to a between-group difference of 47.9% (95% confidence interval, 33.0% to 62.8%). The arthroplasty group outperformed the fusion group in most patient-reported outcome measures (including the ODI, VAS back pain, and all ZCQ component scores) at 24 months postoperatively. There were no significant differences between groups in surgical variables or complications, except that the fusion group had a higher rate of developing symptomatic adjacent segment degeneration. Conclusions: Among patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis, lumbar facet arthroplasty was associated with a higher rate of composite clinical success than fusion was at 24 months postoperatively. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Study Design: Retrospective observational study of consecutive patients Objective: The purpose of the study was to evaluate VBQ as a predictor of interbody subsidence and to determine threshold values that portend increased risk of subsidence. Summary of Background Data: Many risk factors have been reported for the subsidence of interbody cages in anterior cervical discectomy and fusion (ACDF). MRI Vertebral Bone Quality (VQB) is a relatively new radiographic parameter that can be easily obtained from preoperative MRI and has been shown to correlate with measurements of bone density such as DXA and CT Hounsfield Units. Methods: All patients who underwent 1- to 3-level ACDF using titanium interbodies with anterior plating between the years 2018 and 2020 at our tertiary referral center were included. Subsidence measurements were performed by 2 independent reviewers on CT scans obtained 6 months postoperatively. VBQ was measured on pre-operative sagittal T1 MRI by 2 independent reviewers, and values were averaged. Results: Eight-five fusion levels in 44 patients were included in the study. There were 32 levels (38%) with moderate subsidence and 12 levels with severe subsidence (14%). The average VBQ score in those patients with severe subsidence was significantly higher than those without subsidence (3.80 vs. 2.40, P<0.01). A threshold value of 3.2 was determined to be optimal for predicting subsidence (AUC=0.99) and had a sensitivity of 100% and a specificity of 94.1% in predicting subsidence. Conclusions: VBQ strongly correlates with the subsidence of interbody grafts after ACDF. A threshold VBQ score value of 3.2 has excellent sensitivity and specificity for predicting subsidence. Spine surgeons can use VBQ as a readily available screening tool to identify patients at higher risk for subsidence. Level of Evidence: Level—IV

Study Design: Retrospective cohort analysis. Objective: To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications. Background: In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF. Patients and Methods: All adult patients who underwent C2–T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale–Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups. Results: A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P = 0.005) and more likely to have bone morphogenic protein (P < 0.001) and C2 pars screws (P = 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2–C3 segmental lordosis, C2–C3 listhesis, C0–C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2–C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2–C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups. Conclusions: Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF. Level of Evidence: Level III.

Study Design. Retrospective cohort study of prospectively accrued data. Objective. To evaluate a large, prospective, multicentre dataset of surgically treated degenerative cervical myelopathy (DCM) cases on the contemporary risk of C5 palsy with surgical approach. Summary of Background Data. The influence of surgical technique on postoperative C5 palsy after decompression for DCM is intensely debated. Comprehensive, covariate-adjusted analyses are needed using contemporary data. Methods. Patients with moderate to severe DCM were prospectively enrolled in the multicenter, randomized, Phase III CSM-Protect clinical trial and underwent either anterior or posterior decompression between Jan 31, 2012 and May 16, 2017. The primary outcome was the incidence of postoperative C5 palsy, defined as the onset of muscle weakness by at least one grade in manual muscle test at the C5 myotome with slight or absent sensory disruption after cervical surgery. Two comparative cohorts were made based on the anterior or posterior surgical approach. Multivariate hierarchical mixed-effects logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI) for C5 palsy. Results. A total of 283 patients were included, and 53.4% underwent posterior decompression. The total incidence of postoperative C5 palsy was 7.4% and was significantly higher in patients who underwent posterior decompression compared with anterior decompression (11.26% vs. 3.03%, P=0.008). After multivariable regression, the posterior approach was independently associated with greater than four times the likelihood of postoperative C5 palsy (P=0.017). Rates of C5 palsy recovery were comparable between the two surgical approaches. Conclusion. The odds of postoperative C5 palsy are significantly higher after posterior decompression compared to anterior decompression for DCM. This may influence surgical decision-making when there is equipoise in deciding between anterior and posterior treatment options for DCM. Level of Evidence. Therapeutic Level—II

Background: Multisegmental pathologic autofusion occurs in patients with ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH). It may lead to reduced vertebral bone density due to stress shielding. Methods: This study aimed to determine the effects of autofusion on bone density by measuring Hounsfield units (HU) in the mobile and immobile spinal segments of patients with AS and DISH treated at a tertiary care center. The mean HU was calculated for five distinct regions—cranial adjacent mobile segment, cranial fused segment, mid-construct fused segment, caudal fused segment, and caudal adjacent mobile segment. Means for each region were compared using paired-sample t-tests. Multivariable regression was used to determine independent predictors of mid-fused segment HUs. Results: One hundred patients were included (mean age 76 ± 11 years, 74% male). The mean HU for the mid-construct fused segment (100, 95% CI [86, 113]) was significantly lower than both cranial and caudal fused segments (174 and 108, respectively; both p < 0.001), and cranial and caudal adjacent mobile segments (195 and 115, respectively; both p < 0.001). Multivariable regression showed the mid-construct HUs were predicted by history of smoking (−30 HU, p = 0.009). Conclusions: HUs were significantly reduced in the middle of long-segment autofusion, which was consistent with stress shielding. Such shielding may contribute to the diminution of vertebral bone integrity in AS/DISH patients and potentially increased fracture risk.

Background: Pedicle subtraction osteotomy (PSO) is a powerful tool for sagittal plane correction in patients with rigid adult spinal deformity (ASD); however, it is associated with high intraoperative blood loss and the increased risk of durotomy. The objective of the present study was to identify intraoperative techniques and baseline patient factors capable of predicting intraoperative durotomy. Methods: A tri-institutional database was retrospectively queried for all patients who underwent PSO for ASD. Data on baseline comorbidities, surgical history, surgeon characteristics and intraoperative maneuvers were gathered. PSO aggressiveness was defined as conventional (Schwab 3 PSO) or an extended PSO (Schwab type 4). The primary outcome of the study was the occurrence of durotomy intraoperatively. Univariable analyses were performed with Mann–Whitney U tests, Chi-squared analyses, and Fisher’s exact tests. Statistical significance was defined by p < 0.05. Results: One hundred and sixteen patients were identified (mean age 61.9 ± 12.6 yr; 44.8% male), of whom 51 (44.0%) experienced intraoperative durotomy. There were no significant differences in baseline comorbidities between those who did and did not experience durotomy, with the exception that baseline weight and body mass index were higher in patients who did not suffer durotomy. Prior surgery (OR 2.73; 95% CI [1.13, 6.58]; p = 0.03) and, more specifically, prior decompression at the PSO level (OR 4.23; 95% CI [1.92, 9.34]; p < 0.001) was predictive of durotomy. A comparison of surgeon training showed no statistically significant difference in durotomy rate between fellowship and non-fellowship trained surgeons, or between orthopedic surgeons and neurosurgeons. The PSO level, PSO aggressiveness, the presence of stenosis at the PSO level, nor the surgical instrument used predicted the odds of durotomy occurrence. Those experiencing durotomy had similar hospitalization durations, rates of reoperation and rates of nonroutine discharge. Conclusions: In this large multisite series, a history of prior decompression at the PSO level was associated with a four-fold increase in intraoperative durotomy risk. Notably the use of extended (versus) standard PSO, surgical technique, nor baseline patient characteristics predicted durotomy. Durotomies occurred in 44% of patients and may prolong operative times. Additional prospective investigations are merited.