Hamouda, Abdelrahman M.

OBJECTIVE Lordotic devices have garnered increased attention for improving the segmental lordosis (SL) achieved with transforaminal lumbar interbody fusion (TLIF). However, it is unclear the degree to which surgeons maximize the "ideal" or listed lordosis of the interbody device. METHODS Patients undergoing one- or two-level TLIF for degenerative pathologies were identified and data were extracted on demographics, baseline lumbopelvic radiographic parameters, and TLIF details. The primary outcome of interest was the degree to which postoperative SL approximated the listed cage lordosis (Δtarget). Change in SL was a secondary outcome. Linear mixed-effects modeling was used to identify significant predictors of the percentage of ideal lordosis achieved. RESULTS A total of 239 treated levels were included (median patient age 66.6 years; 56.9% female); 151 levels were part of single-level TLIF constructs. The median segmental corrections were a 2.8° increase in SL and 2.8 mm in disc height. The median difference between listed cage lordosis and postoperative SL (Δtarget) was 0.5°. However, only 56.1% of levels achieved at least the listed cage lordosis. Linear mixed-effects modeling found that independent predictors of Δtarget were lower implant lordosis (estimate −1.01° [95% CI −1.15° to −0.87°] per degree, p < 0.001), greater preoperative SL (estimate 0.38° [95% CI 0.28°–0.48°] per degree, p < 0.001), greater preoperative PI (estimate 0.06° [95% CI 0.02°–0.11°] per degree, p = 0.007), and closer approximation of the anterior apophyseal ring of the caudal vertebrae (estimate −0.27° [95% CI −0.39° to −0.15°] per mm, p < 0.001). Similarly, independent predictors of postoperative SL were larger implant lordosis (estimate 0.16° [95% CI 0.05°–0.27°] per degree, p = 0.004), lower preoperative SL (estimate −0.70° [95% CI −0.79° to −0.62°] per degree, p < 0.001), greater preoperative PI (estimate 0.08° [95% CI 0.04°–0.12°] per degree, p < 0.001), and closer approximation of the anterior apophyseal ring of the cranial vertebrae (estimate −0.15° [95% CI −0.28° to −0.03°] per mm, p = 0.014). CONCLUSIONS The present results suggest that while lordosing, only 56% TLIF operations obtain the listed interbody lordosis ("target" lordosis). Anterior placement within the disc space is the only modifiable intraoperative technical factor for maximizing lordosis for a given interbody, highlighting the importance of effective disc space exenteration.

Background For large vessel occlusion (LVO) ischemic strokes, three major techniques of mechanical thrombectomy (MT) have demonstrated efficacy. Here we compare the safety and efficacy of stent retrievers (SR), contact aspiration (Asp), and a combined mechanical thrombectomy (cMT) for LVO ischemic stroke. Methods Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we queried the PubMed, EMBASE, Scopus, and Web of Science databases for studies published prior to December 2024 describing patients with ischemic stroke who underwent MT using SR, Asp, or cMT. Results Twnety-four studies comprising a total of 12 845 patients were included in the analysis. Compared with cMT, Asp was associated with a lower rate of first pass effect (FPE) (risk ratio (RR) 0.67; 95% CI 0.46 to 0.96), shorter procedure duration (mean difference (MD) −13.35 min; 95% CI −20.83 to –5.87), and lower risk of arterial dissection (RR 0.50; 95% CI 0.29 to 0.87). Additionally, SR use was linked to a higher procedure duration compared with Asp (MD 13.39 min; 95% CI 5.55 to 21.22) and a lower symptomatic intracranial hemorrhage rate (RR 0.75; 95% CI 0.59 to 0.96). No significant differences were observed between groups in terms of number of passes, successful recanalization, 90-day functional outcomes, mortality, arterial perforation, or embolization to new territory. Conclusions All three techniques demonstrated similar recanalization rates and functional outcomes. However, Asp was associated with shorter procedure times and fewer arterial dissection complications, while cMT showed a higher FPE. Given the comparable overall efficacy, the choice of technique should be guided by the physician’s preference, expertise, and confidence, tailored to the individual patient’s profile.

Background Guide catheter (GC) placement, whether distal or proximal, may influence the efficacy and safety of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, definitions of placement and procedural strategies vary across studies, limiting clarity. Methods We systematically searched PubMed, Embase, Scopus, and Web of Science from inception to September 1, 2024. Comparative studies of adult patients with anterior circulation AIS-LVO undergoing MT that reported GC placement were included. Both balloon GCs (BGCs) and non-BGCs were eligible. Data were pooled using random-effects models in R. Outcomes included functional independence (modified Rankin Scale 0–2 at 90 days), successful reperfusion (modified thrombolysis in cerebral infarction ≥2b or expanded thrombolysis in cerebral infarction ≥2c), first-pass recanalization (FPR), mortality, puncture-to-recanalization (PTR) time, and complications. Subgroup analyses were performed by thrombectomy technique and catheter type. Results Seven retrospective studies comprising 2148 patients (1042 proximal, 1106 distal) were analyzed. Distal placement was associated with higher rates of functional independence (risk ratio (RR): 1.25, 95% confidence interval (CI): 1.10–1.42), successful reperfusion (RR: 1.13, 95% CI: 1.04–1.22), and FPR (RR: 1.35, 95% CI: 1.15–1.58), as well as lower 90-day mortality (RR: 0.52, 95% CI: 0.28–0.82). PTR time was shorter with distal placement (mean difference: −7.7 min, 95% CI: −10.8 to −4.6). No significant differences were observed for symptomatic intracranial hemorrhage (RR: 0.96, 95% CI: 0.55–1.65) or emboli to new territory (RR: 0.84, 95% CI: 0.28–2.52). Benefits were consistent across both BGCs and non-BGCs. Heterogeneity existed in outcome definitions and techniques, and publication bias could not be excluded. Conclusions Distal GC placement is associated with improved reperfusion, efficiency, and functional outcomes in MT for anterior circulation AIS-LVO, without increased complications. Given the retrospective nature of included studies, anatomic confounding, and inconsistent outcome definitions, findings should be considered preliminary. Multicenter trials are needed to confirm whether catheter position independently predicts MT outcomes.

OBJECTIVE Proximal junctional kyphosis (PJK) affects 5%–61% of patients following thoracolumbar fusion. Many patients are asymptomatic, but a plurality require surgical revision at a cost of $75,000 per case. This analysis sought to analyze the degree to which bone quality and paraspinal muscle sarcopenia influence PJK failure mode. METHODS Patients undergoing thoracolumbar instrumented fusion with an upper instrumented vertebra (UIV) at the thoracolumbar junction (T10–L2) were identified and data were gathered on surgery, bone quality, pre- and postoperative sagittal alignment, and paraspinal muscle cross-sectional area (CSA). PJK was defined as a ≥ 10° increase in proximal junctional angle from the first postoperative radiograph. PJK was classified as discoligamentous failure (type 1), bone failure (type 2), or screw-bone interface failure (type 3) according to the Yagi-Boachie system. Bone quality was assessed by Hounsfield units (HUs) and the vertebral bone quality (VBQ) score at the UIV. RESULTS One hundred fifty patients were identified (median age 67 years, 53.3% female), 46 of whom experienced PJK (22 type 1, 13 type 2, 11 type 3). The median time to onset was most rapid for type 2 events (2.6 months). There were no differences between patients experiencing PJK versus controls regarding bone quality (HUs or VBQ score) or paraspinal muscle CSA on univariate comparison. However, subdivision by PJK type showed patients experiencing bone failure (type 2) PJK had significantly lower HUs at the UIV and UIV+1 relative to those experiencing type 1 PJK or no PJK (all p < 0.05). The VBQ score trended toward being significant, with a higher VBQ score (worse bone quality) in those suffering type 2 PJK, but did not reach statistical significance (p = 0.07). Patients experiencing discoligamentous failure PJK (type 1) had small multifidus CSA (390 mm 2 ) relative to patients experiencing type 2 (516 mm 2 ) or type 3 (440 mm 2 ) PJK and patients who did not experience PJK (481 mm 2 ), although the difference did not reach statistical significance. On time-to-event analysis, low HUs of the UIV/UIV+1 predicted type 2 (hazard ratio [HR] 0.81, 95% CI 0.70–0.93; p = 0.002) and type 2/3 PJK (HR 0.87, 95% CI 0.78–0.96; p = 0.006) but not type 1 PJK. Low UIV multifidus CSA trended toward being a significant predictor of type 1 PJK (HR 0.85, 95% CI 0.69–1.05; p < 0.10). CONCLUSIONS The combination of underlying bone quality and paraspinal musculature CSA at the UIV appeared to influence failure mode among patients who underwent lumbosacral instrumented fusion terminating at the thoracolumbar junction.

Study Design Retrospective cohort analysis. Objective (1) Develop a novel computed tomography (CT)-based assessment of endplate bone density (EP-HU), (2) Determine if EP-HU was a stronger predictor than trabecular HU for subsidence after transforaminal lumbar interbody fusion (TLIF). Methods All adult patients who underwent single-level TLIF for lumbar degenerative conditions at an academic center between 2017-2022 were retrospectively identified. EP-HU was calculated from a 2 mm superior and inferior endplate region on the preoperative mid sagittal CT scans, accounting for surface undulations. Lumbar vertebral HUs (trabecular region) were determined in a standard fashion on axial CT. EP-HU + vertebral HU served as an aggregate bone quality metric. Interbody subsidence (≥2 mm threshold) was directly measured on the endplate-facing surface of 1 year CT scans. Univariate and multivariate analysis compared subsidence based on CT bone metrics. Results A total of 114 patients met the inclusion/exclusion criteria. There was no significant difference in fusion or reoperation rate based on subsidence occurrence. Both vertebral HU ( P = .012) and EP-HU ( P < .001) were associated with subsidence. In receiver operating curves, EP-HU was more optimal for subsidence prediction than vertebral HU, but the aggregate metric further optimized the specificity and total area under the curve. In a predictive logistic regression model EP-HU + vertebral HU (aggregate HU < 515 odds ratio: 7.82, P < .001) was a strong independent predictor of subsidence. Conclusion Preoperative calculation of EP-HUs in addition to vertebral HUs may enhance prediction of TLIF subsidence where aggregate endplate and vertebral HU < 515 can be used to identify high risk patients.

OBJECTIVE Idiopathic normal pressure hydrocephalus (iNPH) is characterized by gait deterioration, cognitive disturbances, and urinary incontinence. Gait deficits pose safety hazards due to frequent falls, yet objective investigations of gait improvement following ventriculoperitoneal shunt (VPS) placement are limited. Therefore, the aim of this study was to assess objective improvement in gait parameters for patients with iNPH after VPS placement. METHODS All patients treated with a VPS for iNPH by the senior author at a single tertiary care center from December 2017 to January 2023 were retrospectively reviewed. Patients who underwent detailed motion analysis testing before surgery with > 1 follow-up assessment were included. Analyzed parameters included gait velocity, gait cadence, stride length, stride width, gait stability ratio, total support, and single support. Time-dependent linear mixed-effects models and generalized additive mixed-effects models (GAMMs) were used to model short-term and longitudinal gait parameter changes, respectively. RESULTS A total of 212 patients (137 male, median age was 75.2 years) who underwent VPS placement for iNPH were included, with a total of 747 gait analyses performed at a median last-gait analysis follow-up duration of 12.0 months. Statistically significant changes in all gait parameter values were seen between the preoperative time point and first postoperative follow-up (within 3 months) time point (paired Wilcoxon p < 0.001), with a statistically significant majority of patients experiencing improvement (binominal p < 0.0001). Longitudinal analyses using a GAMM showed increased gait velocity, single support, and stride length, with decreased stability ratio, step width, and total support at early time points, while a plateau was achieved around 6 months. CONCLUSIONS A detailed gait analysis demonstrated significant improvements in objective ambulation metrics, particularly in the gait velocity, stride length, and gait stability ratio, following VPS placement in patients with iNPH. Most patients maintained marked improvement from baseline to the last follow-up assessment, although a plateau of the benefit was experienced over longer follow-up.

OBJECTIVE The purpose of this study was to evaluate the risks and benefits of removing painful pelvic/iliac screws in spine fusion surgery patients. METHODS A retrospective review identified patients who had traditional iliac and S2-alar-iliac (S2AI) screws removed for pain. The minimum follow-up was 24 months. RESULTS Fifty-two patients (75% women) were included with a mean age of 63 years, BMI of 28, and follow-up of 65 months. Most of the removed screws were S2AI (83%) compared with traditional iliac screws (17%). Forty-three patients (83%) had improvement in their pelvic screw related–pain following removal. Eight patients (15%) experienced lumbosacral mechanical complications following pelvic screw removal including sacral fracture (n = 3, 6%) and/or L4–5 or L5–S1 rod fracture (n = 7, 13%). On multivariable analysis, risk factors for mechanical complications following pelvic screw removal included a longer fusion construct (OR 1.34, p = 0.035), greater postoperative L4–S1 lordosis (OR 1.14, p = 0.04, ideal cutoff > 40°), and lack of bone morphogenetic protein (BMP; OR 0.03, p = 0.02). Ten patients (19%) underwent subsequent SI joint fusion following pelvic screw removal, and higher standing pelvic incidence (OR 1.10, p = 0.03) was the only independent predictor of SI fusion. CONCLUSIONS Removal of painful pelvic screws resulted in a high rate of postoperative pain relief, albeit with a risk of lumbosacral mechanical complications and subsequent SI joint fusion. Patients at risk for lumbosacral mechanical complications following pelvic screw removal included those with longer fusion constructs, more lordosis from L4 to S1 (> 40°), and lack of BMP. Patients at risk for receiving an instrumented SI joint fusion following pelvic screw removal included those with a higher pelvic incidence.

Study Design Retrospective Cohort Study. Objectives To determine if 3D printed porous titanium (Ti) cages compared to non-porous polyetheretherketone (PEEK) cages predicted improved fusion rate or clinical outcomes after transforaminal lumbar interbody fusion (TLIF). Methods All adult patients who underwent one- and two-level TLIF for degenerative conditions by a single surgeon at an academic center between 2017-2021 were retrospectively identified. Patients were dichotomized into porous Ti and non-porous PEEK interbody cage groups. Fusion status was assessed by at 6-months and 1-year postoperatively by CT Bridwell scale and flexion/extension X-Rays. Postoperative complications (CT-based subsidence, adjacent segment disease, reoperation rates) and interval changes in lumbar radiographic alignment at short- and long-term follow-up were determined. Univariate and multivariate analysis compared patient and surgical factors, fusion rates, alignment, and complications across interbody groups. Results A total of 136 patients with 169 unique fusion levels (125 Ti cages, 44 PEEK cages) met the inclusion/exclusion criteria. Ti relative to PEEK interbodies had significantly decreased surface area and increased height and lordosis. Ti cage use was associated with greater subsidence ( P < 0.001) but did not independently predict maximum subsidence on regression ( P = 0.109). In the overall cohort, there were no significant differences in fusion rates or lumbopelvic alignment between interbody groups. Reoperation (Ti: 10.9% vs PEEK: 28.6%, P = 0.026) and reoperation for pseudoarthrosis (Ti: 2.0% vs PEEK: 11.4%, P = 0.038) was significantly more likely in the PEEK relative to the Ti group. Conclusions Use of 3D printed porous Ti cages relative to non-porous PEEK cages may mitigate pseudoarthrosis related reoperation after TLIF.

OBJECTIVE Pelvic incidence (PI) is a key parameter of sagittal alignment. While conventionally held to be fixed, increasing evidence suggests PI may be variable. This study aimed to identify predictors of change in PI with patient position and to assess the association of preoperative radiographic characteristics and intraoperative maneuvers with postoperative PI. METHODS Patients who underwent thoracolumbosacral fusion were identified, and data were gathered on preoperative spinopelvic parameters, patient demographic characteristics, and operative details. Preoperative spinopelvic parameters were measured on upright, supine, and prone radiographs. Univariable comparisons of PI between the different patient positions were performed. Multivariable analysis was performed to identify variables independently correlated with PI on 6-week postoperative radiographs. Change in PI was defined as ≥ 5° change between positions. RESULTS In total, 138 patients were identified (mean ± SD age 66.0 ± 8.7 years; 38.4% male). Statistically significant differences in PI were noted between preoperative standing and supine (mean −3.2° ± 4.2°, p < 0.001), preoperative supine and prone (3.5° ± 4.7°, p < 0.001), preoperative and 6-week postoperative standing (1.5° ± 6.2°, p = 0.01), and immediate and 6-week upright (1.1° ± 3.9°, p = 0.007) radiographs. Univariable comparisons showed PI decrease from standing to supine was predicted only by weight (87.0 ± 15.0 vs 81.1 ± 19.3 kg, p = 0.04); there were no significant predictors of increase in PI from standing to prone. Increase in PI from preoperative to 6-week standing radiographs was predicted by lower preoperative PI class (p < 0.001), L5/S1 interbody placement (74.4% vs 52.0%, p = 0.02), and change in PI from preoperative standing to supine (12.8% vs 39.8%, p = 0.002) and from standing to prone (51.3% vs 13.3%, p < 0.001). Multivariable analysis showed that 6-week postoperative PI was associated with only preoperative supine PI (B = 0.293, 95% CI 0.10–0.48, p = 0.003) and prone PI (B = 0.647, 95% CI 0.44–0.85, p < 0.001). CONCLUSIONS There are position-dependent changes in PI among patients without prior pelvic fixation. Statistically significant changes in PI are seen even after pelvic fixation with a single S2-alar-iliac screw bilaterally. Postoperative PI was best predicted by preoperative PI on supine and prone radiographs rather than upright radiographs, suggesting that preoperative prone and supine radiographs may provide surgeons with the best information for achieving PI–lumbar lordosis mismatch < 10°.