Hamouda, Abdelrahman M.

OBJECTIVE Transforaminal lumbar interbody fusion (TLIF) offers both indirect decompression and segmental correction through restoration of disc height. However, stresses exerted on the vertebral endplates by the interbody device can result in implant subsidence and loss of correction. The present time-to-event analysis aimed to identify predictors of interbody subsidence. METHODS Patients who underwent 1- or 2-level TLIF were identified. Data on demographics, surgical details, preoperative bone quality using CT-based Hounsfield units (HU), and pre- and postoperative lumbopelvic parameters were collected. Univariable analyses were conducted to identify predictors of subsidence (≥ 2-mm intrusion of interbody into cranial or caudal vertebrae) and significant subsidence (≥ 4-mm intrusion). Multivariable Cox regression was performed to identify independent predictors of subsidence, expressed as hazard ratios with 95% confidence intervals. RESULTS A total of 198 patients treated at 241 levels were included (median age 66.6 years, IQR 59.5, 73.7 years; 56.6% were women). In 92 levels (38.2%) there was some subsidence and in 25 (10.4%) there was significant subsidence. Implanted levels demonstrating subsidence (≥ 2 mm) were associated with lower HU in cranial and caudal vertebrae; had interbodies positioned farther from the anterior apophyseal ring; were implanted with taller, more lordotic interbodies; and underwent greater disc height restoration. Those showing significant subsidence (≥ 4 mm) were similarly associated with lower HU in the cranial and caudal vertebrae; had interbodies positioned farther from the anterior apophyseal ring of the caudal vertebrae; and underwent greater disc height restoration. Multivariable Cox regression showed that time to subsidence was predicted by greater implant height (HR 1.20/mm, 95% CI 1.05–1.38; p = 0.009), greater postoperative disc height (HR 1.21/mm, 95% CI 1.09–1.34; p < 0.001), and greater disc height restoration (HR 1.11/mm, 95% CI 1.04–1.19; p = 0.002). The time-to-subsidence analysis for significant (≥ 4 mm) subsidence showed that it was predicted by lower HU in the cranial vertebrae (HR 0.98/unit, 95% CI 0.97–0.99; p = 0.001); increasing number of levels instrumented (HR 1.26, 95% CI 1.04–1.52; p = 0.016); and greater disc height restoration (HR 1.33/mm, 95% CI 1.18–1.51; p < 0.001). CONCLUSIONS This time-to-event analysis suggests that interbody subsidence following TLIF is best predicted by implantation of a taller interbody and aggressive disc height restoration. Significant subsidence is similarly predicted by aggressive disc height restoration along with poor baseline bone quality. The results suggest the need to balance aggressive correction at the time of surgery against the increased risk of subsequent interbody subsidence.

Introduction: Bone health optimization is a key component of the preoperative management of spine surgery patients, as poor bone quality increases the odds of mechanical complications. The present study aimed to achieve the following: (1) compare the relative efficacy of current osteoporosis medications in improving bone quality; (2) identify factors influencing treatment response in preoperative spine surgery patients. Methods: Patients treated at a single, multisite institution who received osteoporosis treatment were identified. Data were gathered on pre- and post-treatment lumbar spine Hounsfield Unit (HU) measurements, patient demographics, frailty scores (modified Frailty Index/mFI, risk analysis index/RAI), and pharmacologic treatment details. The primary outcome was a ≥7 point improvement in lumbar HU, and baseline and logistic regression models were utilized to identify factors associated with this improvement. Medications were grouped as anabolic (teriparatide, romosozumab) and antiresorptive (denosumab, alendronate) therapies. Results: A total of 267 patients were included (median age: 74 years; IQR [66–81]; 67.3% female), with 127 (47.6%) improving by ≥7 HU. The treatment agents used were alendronate (95), denosumab (113), romosozumab (31), and teriparatide (28). Univariable comparisons revealed significant differences across medication groups in age (p < 0.001), sex (p < 0.001), mFI (p < 0.001), RAI (p = 0.004), BMI (p < 0.001), pre-treatment HU (p = 0.022), and treatment duration (p < 0.001). The highest HU improvement rates (ΔHU ≥ 7) were observed in patients receiving the anabolic medications romosozumab (67.7%) and teriparatide (60.7%). Univariable logistic regression identified male sex (OR 0.54, p = 0.019), higher pre-treatment HU (OR 0.99, p = 0.006), and longer treatment duration (OR 0.97, p = 0.003) as factors associated with lower odds of HU improvement. Only romosozumab was associated with significantly higher odds of HU improvement relative to alendronate (OR 3.02, p = 0.012). In our multivariable analysis, male sex (OR 0.53, p = 0.028) and higher pre-treatment HU (OR 0.99, p = 0.002) remained significant predictors of HU improvement. However, medication type was not significant in the multivariable analysis. Conclusions: Our study highlights that male sex and higher pre-treatment HU were independently associated with lower odds of HU improvement, while medication type was not a significant predictor. Additionally, anabolic agents offered superior improvement relative to antiresorptive therapies.

OBJECTIVE The aim of this study was to determine independent risk factors for vertebral compression fracture (VCF) following stereotactic body radiation therapy (SBRT) in metastatic spine disease. METHODS Patients treated with SBRT for spinal metastasis at a single tertiary care center between 2008 and 2019 were retrospectively identified. Patients with CT scans obtained within 1 year of SBRT completion were included. Variables collected included demographics, Spine Instability Neoplastic Score (SINS), primary tumor pathology, Weinstein-Boriani-Biagini (WBB) classification, chemoradiation treatment details, and bone quality as assessed by Hounsfield units (HUs) on CT. HUs were measured for the medullary bone of the metastatic level, the tumor, and the vertebral bodies cephalad and caudal to the metastasis. Multivariable logistic regression was used to identify predictors of post-SBRT pathological fracture. RESULTS A total of 292 patients (mean age 66 years) with 392 unique lesions were included. The most common pathologies were prostate (n = 193), kidney/renal cell (n = 46), and lung (n = 33). The most common tumor levels were thoracic (n = 206 lesions) and lumbar (n = 128 lesions). SBRT was generally delivered in 1–3 fractions with doses ranging from 16 to 24 Gy in 1 fraction and 24–36 Gy in 3 fractions. Of the 392 lesions, 73 suffered VCF: 21 (29%) with < 25% height loss, 15 (21%) with 25%–40% height loss, and 37 (51%) with > 40% height loss. On univariate analysis, patients with VCF had lower average HUs (156 ± 52 vs 202 ± 89, p < 0.001), more WBB sectors involved (3 ± 2 vs 3 ± 1, p < 0.001), higher SINSs (8 ± 3 vs 6 ± 2, p < 0.001), were more commonly female (33% vs 22%, p = 0.05), and more commonly had nonprostate pathology (67% vs 47%, p = 0.003). VCF rates were similar between moderate (< 20 Gy in 1 fraction, < 30 Gy in 3 or 5 fractions) and high-dose (> 20 Gy in 1 fraction, > 30 Gy in 3 or 5 fractions) radiation schema (15% VCF vs 16% no VCF, respectively; p = 0.99). On multivariable logistic regression, independently significant predictors of VCF were HUs ≤ 229 (OR 6, p < 0.001), affected levels ≥ 3 WBB segments (OR 3, p < 0.001), and an SINS ≥ 8 (OR 2, p = 0.02). CONCLUSIONS Low pre-radiation HUs, involvement of more WBB sectors, and a higher SINS were independent predictors of VCF following SBRT for metastatic spine disease.

BACKGROUND AND OBJECTIVES: Transforaminal lumbar interbody fusion (TLIF) allows for direct and indirect decompression and segmental lordosis in sagittal plane correction. This study compares the effectiveness of “Bullet” type and “Banana” type devices for sagittal plane correction. METHODS: Patients who underwent 1-level or 2-level TLIF for degenerative pathology at a single tertiary care center were identified. Details were extracted on demographics, interbody dimensions, and preoperative and postoperative lumbopelvic parameters from upright radiographs. Cages were categorized as “Bullet” or “Banana” type based on morphology and manufacturer description of optimal position. Univariable comparisons between levels treated with “Bullet” and “Banana” type interbodies were performed. Multivariable linear regression was performed to identify independent predictors of postoperative segmental lordosis and change in segmental lordosis. RESULTS: One hundred and ninety eight unique patients (median 66.6 years; [IQR 59.5, 73.7]; 56.6% female) were included with 241 levels treated, of which 114 (52.7%) were treated with “Banana” type interbodies and 127 (47.3%) with “Bullet” type. “Banana” type interbodies afforded both greater postoperative segmental lordosis (8.1 [6.2, 10.7] vs 7.5 [5.2, 9.6]; P = .048) and greater increase in segmental lordosis (3.3 [0.7, 7.0] vs 2.3 [0.1, 4.2]; P = .015). On multivariable linear regression, only preoperative segmental lordosis (β = 0.322 per degree; [0.244, 0.399]; P < .001), implant listed lordosis (β = 0.146 per degree; 95% CI [0.048, 0.244]; P = .004), preoperative pelvic incidence (0.072 per degree; [0.034, 0.111]; P < .001), and use of bilateral TLIF windows (β = 3.133; [1.213, 5.053]; P = .001) were predictive of postoperative segmental lordosis. CONCLUSION: The present analysis suggests that baseline lumbopelvic anatomy, interbody lordosis, and the use of bilateral TLIF windows are the most important predictors of postoperative segmental lordosis. Use of “Banana” vs “Bullet” type interbodies was not predictive of segmental lordosis achieved on immediate postoperative upright radiographs. Further work is merited to determine whether the 2 interbody types demonstrate differences regarding subsidence risk or maintenance of correction.

Background/Objectives: Both poor bone quality and paraspinal sarcopenia have been suggested as risk factors for proximal junctional kyphosis (PJK) at the upper instrumented vertebra (UIV) following long-segment thoracolumbar fusion. Methods: Adults ≥50 with a T1-6 UIV were identified, and data were gathered on pre- and postoperative spinopelvic parameters, bone quality (using Hounsfield units and vertebral bone quality score), and paraspinal cross-sectional area at L3 and the UIV. PJK was defined by a ≥10° increase in the proximal junctional angle. Cox regressions were performed to identify PJK risk factors; PJK was subdivided into types 1–3 based on the Yagi–Boachie classification. Results: In total, 15/76 patients (median age 66; 72.4% female) experienced PJK; 10 experienced type 1, 4 experienced type 2, and one experienced type 3. Univariable Cox regression showed that PJK was negatively correlated with total paraspinal muscle CSA at the UIV (HR 0.74/100 mm2; 95% CI [0.57, 0.6]; p = 0.02). Lower total paraspinal CSA at L3 (HR 0.94/100 mm2; p = 0.07) and higher postoperative global tilt (HR 1.03; p = 0.09) also trended toward significance. Similarly, type 1 PJK was predicted by smaller total paraspinal CSA at the UIV (HR 0.64/100 mm2; [0.45, 0.92]; p = 0.02). Paraspinal CSA was not predictive of type 2 PJK, but lower HU at the UIV and UIV + 1 trended toward significance (HR 0.98/unit; p = 0.16). A comparison of type 1 and 2 PJK showed a higher average of paraspinal CSA and a lower average of HU at the UIV. Conclusions: Global alignment and paraspinal sarcopenia were most predictive of PJK, though paraspinal sarcopenia was only predictive of type 1. Type 2 may be better predicted by bone quality.

Background For unruptured intracranial aneurysms (UIAs), conservative management is often possible. However, when direct treatment is warranted, endovascular treatments (EVTs) provide an effective minimally invasive approach. These procedures still necessitate careful patient monitoring, frequently in the Intensive Care Unit (ICU). The factors leading to ICU admission for these patients remains an area of debate. Objective This systematic review aims to highlight existing literature and identify gaps in understanding the factors contributing to ICU admission following EVTs for UIAs. Methods We utilized the Nested Knowledge Autolit semi‐automated software to gather studies published before April 2024. We followed the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines, and included studies that met predetermined population, intervention, control, and outcomes (PICO) criteria. Statistical analysis was performed using R software. Results We retrieved 181 studies and 9 met our inclusion criteria. There was significant variability across these studies on what factors they reported. Across included studies there were 8,098 patients, with 5,620 requiring ICU admission following EVTs for UIAs. Analysis revealed that anterior aneurysm location, aneurysm‐related symptoms, and procedure length were significant factors leading to ICU admission. The overall ICU admission rate was approximately 24.61 per 100 patients. Conclusion This review underscores the need for further research to understand what factors lead to ICU admission following EVTs for UIAs. Additional studies are needed that use a standardized approach to collect data on patient demographics, aneurysm characteristics, procedural details, and postoperative outcomes. Such studies will allow for concrete recommendations to be made on ICU needs and prognostic calculators to be developed in order to support clinical decisions and lower healthcare costs.

Background Diagnostic Cerebral Angiography (CA) is a relatively common procedure that provides detailed evaluation of the brain's blood vessels. With the growing preference for Transradial artery (TRA) access over Transfemoral artery (TFA) access, our review aims to compare clinical outcomes and complications associated with these two approaches. Methods We carried out a systematic review using PubMed, Embase, Web of Science, Scopus databases, following the Preferred Reporting Items for Systematic reviews and Meta‐Analyses (PRISMA) guidelines. Inclusion was limited to studies that exclusively compared TRA versus TFA approaches for cerebral diagnostic purposes. Results Our study included 27 studies encompassing a total of 12,806 patients. The TRA arm comprised 6,284 patients with a median age of 57.9 years (range: 13.6‐78.2), and 46.4% were male (range: 27.8%‐82%). The TFA arm included 6,522 patients with a median age of 59.0 years (range: 13.0‐79.3), and 44.8% were male (range: 20.7%‐78.4%). Our analysis revealed that the TFA group had a higher successful Cerebral Angiography (CA) rate (OR= 0.62, CI [0.40; 0.95], p=0.03), and lower crossover rate (OR: 2.85, CI [1.39; 5.84], p<0.01) compared to the TRA group. However, the TRA group demonstrated a significantly lower rate of total complications (OR: 0.52, CI [0.33; 0.82], p<0.01, I 2 =59%, p< 0.001) and shorter hospital length of stay (LOS) in hours ([MD]: ‐33.25, CI [‐51.40; ‐15.11], p< 0.001) compared to the TFA group. There were no significant differences between groups in terms of puncture time, procedural time, mean contrast dose, radiation exposure, and radiation dose. Conclusion The choice of access site for cerebral angiography depends on various factors, including facility protocol, provider preference, vascular anatomy, and patient preferences. Our review highlighted the superiority of the transfemoral artery approach in terms of success rates and lower crossover rates. However, transradial artery access may be preferred due to its association with lower complication rates and shorter hospital stays, aligning with patient‐centered outcomes.

OBJECTIVE Hounsfield units (HUs) may better predict biomechanical complications of instrumented fusion than conventional bone quality measures. Typically, noncontrast axial slices are used. This study aims to address the influence of reconstruction plane and contrast administration on measured HUs in patients undergoing lumbar spine imaging. METHODS Patients without prior spine surgery, infection, or tumor were identified for 3 groups: 1) 150 patients with high-resolution noncontrast lumbar CT, 2) 109 patients with noncontrast and contrast-enhanced lumbar CT, and 3) 100 patients with noncontrast lumbar CT and lumbar CT myelograms. Noncontrast HU measures in group 1 were compared between axial, sagittal, and coronal reconstructions. HU measures for groups 2 and 3 were compared on axial slice averages. HU measures between groups were compared using the Wilcoxon signed-rank test to investigate the presence of a statistically significant difference between groups (α = 0.05). Linear regression was also used to determine the degree of correlation between HU measures on noncontrast axial CT slices and HU measures on other sequences. RESULTS The mean patient age was 58.8 ± 15.9 years for group 1 (54.0% male), 65.5 ± 15.9 years for group 2 (61.5% male), and 65.2 ± 14.2 years (53.5% male) for group 3. Comparison of HU measures in group 1 showed significant differences across measurement modalities with the exception of axial average versus coronal average measures (p = 0.257) and sagittal average versus midsagittal measures (p = 0.726). There were significant differences in average axial HUs for each vertebral body between contrast and noncontrast lumbar CT and between CT myelography and noncontrast CT. Linear regression analysis demonstrated an extremely high correlation between measures for all methodologies (r2 = 0.950–0.986, all p < 0.001), and between contrast-enhanced and noncontrast studies (r2 = 0.870, p < 0.001). Measurements on CT myelography were significantly correlated with those in noncontrast studies, although to a lesser degree (r2 = 0.745, p < 0.001). CONCLUSIONS HU measures on noncontrast CT appear similar across multiple different planes, suggesting that a simpler methodology such as single-slice measurement on midsagittal reconstruction may allow for more rapid assessment of underlying bone quality. Consistent with prior work, contrast-enhanced CT sequences appear to reliably mirror underlying bone quality, although CT myelogram measures may vary in a more unpredictable way that precludes their use to interpret underlying bone quality. HU measures on contrast-enhanced studies are on average greater, suggesting the need for higher cutoff values.