Search Results (73)

Background/Objectives: To determine whether ESS provides superior clinical, radiologic, or perioperative outcomes compared with non-ESS surgical strategies in lumbar spondylolisthesis. Methods: We conducted a PRISMA-guided systematic review and meta-analysis comparing ESS with non-ESS strategies specifically for lumbar spondylolisthesis. PubMed, Web of Science, Scopus, and CENTRAL were searched from inception to December 2025, plus reference-list screening. Primary outcomes were mean change in VAS back pain, VAS leg pain, and Oswestry Disability Index (ODI); secondary outcomes included radiologic measures (disc height, lumbar lordosis angle, fusion rate) and perioperative outcomes (blood loss, operative time, length of stay, complications). Results: Eighteen studies (16 retrospective cohorts, 1 RCT, 1 case–control) involving 1200 patients with lumbar spondylolisthesis (2019–2025) were included. ESS showed no significant differences versus non-ESS in mean change in VAS back pain (13 studies; MD −0.07), VAS leg pain (14 studies; MD 0.08), or ODI (12 studies; MD 0.51). No statistically significant differences were detected in radiological outcomes (disc height, lumbar lordosis angle, and fusion rate). ESS was associated with reduced blood loss (MD −132.98) and shorter hospital stay (MD −2.86 days), with no difference in operative time (MD 3.96) or postoperative complications (RR 0.86). Subgroup analyses compared endoscopic fusion with MIS fusion, open fusion, and non-endoscopic decompression. Endoscopic versus MIS fusion showed lower blood loss (MD: −50.9 mL) and shorter hospital stay (MD: −1.4 days) but longer operative time (MD: +17.2 min), with no differences in clinical outcomes. Comparisons involving decompression and open fusion were limited by the small number of studies and should be considered exploratory. Conclusions: For lumbar spondylolisthesis, no statistically significant differences were detected between ESS and non-endoscopic approaches in pain, disability, radiologic outcomes, or complication rates, with potential perioperative advantages in blood loss and length of stay. However, these findings should be interpreted cautiously because the available evidence is predominantly retrospective, procedurally heterogeneous, and affected by substantial variation in follow-up duration. Full article

Background: Cage subsidence after minimally invasive transforaminal lumbar interbody fusion raises revision risk and costs. Intraoperative computed tomography (CT) provides high-resolution, three-dimensional visualization of the endplate–cage interface and serves as a practical—though itself imperfect—reference standard for early subsidence, but it is not available at all institutions. Plain X-ray is widely available and inexpensive, but lower in resolution. The clinically relevant question is therefore not whether CT and X-ray are equivalent, but rather which X-ray protrusion depth measurement most reliably identifies CT-confirmed subsidence, and whether a positive intraoperative CT meaningfully predicts later radiographic subsidence. Objective: Using intraoperative CT as reference, we aimed to (1) determine the optimal X-ray protrusion depth threshold for CT-confirmed early subsidence; (2) test whether intraoperative CT predicts late radiographic subsidence; and (3) examine how early X-ray depth relates to intervertebral disc height (IVDH) and segmental lordosis (SL) loss. Methods: In a retrospective single-surgeon cohort (March 2015–July 2023), subsidence was defined as ≥2.0 mm endplate penetration on CT and measured on X-ray by parallax technique. Sensitivity, specificity, accuracy, and Cohen’s κ were calculated. Receiver operating characteristic (ROC) analysis evaluated X-ray depth as a continuous predictor and identified the Youden-optimal cutoff. Intraoperative CT was tested against late radiographic subsidence; no-intercept linear models estimated per-millimeter IVDH and SL loss. Results: Of 100 patients, 93 had paired imaging (mean age 66.7 years; body mass index 26.8 kg/m²). Subsidence appeared on CT in 16.1% and on X-ray in 15.1%. X-ray showed 80.0% sensitivity, 97.4% specificity, 94.6% accuracy, and κ = 0.80; ROC analysis demonstrated strong discrimination (area under the curve 0.91; 95% confidence interval 0.81–1.00), Youden-optimal cutoff 1.90 mm. Intraoperative CT predicted late subsidence (n = 76) with only 45.8% sensitivity and 96.2% specificity; missed cases had penetration depths indistinguishable from non-subsiders. Each 1 mm of early X-ray depth corresponded to 0.45 mm IVDH and 0.37° SL loss. Conclusions: An X-ray protrusion depth of 2.0 mm reliably identifies CT-confirmed early subsidence, providing a preliminary diagnostic cutoff for use when CT is unavailable. Intraoperative CT is highly specific but insensitive for late subsidence; meaningful risk stratification will require additional inputs. These hypothesis-generating findings warrant prospective validation. Full article

Endoscopic spine surgery (ESS)—including full-endoscopic transforaminal and interlaminar techniques, and unilateral biportal endoscopy (UBE)—offers patients smaller incisions, preserved paraspinal muscle, and faster recovery. Because the working corridor is narrow, intraoperative fluoroscopy plays a larger role than in open or microscopic approaches, making radiation exposure worthy of attention for both patients and surgeons. This narrative review aims to be a practical resource for the endoscopic spine surgeon. We synthesize the available literature on typical radiation doses across the main ESS techniques, compare them with minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open alternatives, review the factors that drive exposure, and walk through the full menu of dose-optimization options—from simple measures such as collimation, pulsed fluoroscopy, and leaded eyewear, through navigation platforms, to robotic guidance. A consistent practical observation is that the simplest, least expensive interventions often deliver the largest dose reductions. Capital-intensive technologies add real value, particularly for endoscopic interbody fusion, and work best alongside rather than in place of these basics. With routine dosimetry and straightforward as-low-as-reasonably-achievable (ALARA) practices, surgeons can continue to build on the already favourable profile of ESS while keeping radiation exposure low. Conclusions are tempered by the largely retrospective and heterogeneous nature of the underlying evidence. Full article

Adjacent segment degeneration remains a major biomechanical concern after lumbar fusion, whereas fully dynamic topping-off constructs may provide an alternative strategy by preserving segmental motion and unloading degenerated discs. In this study, a three-dimensional nonlinear finite element model of the L1-L5 lumbar spine with L3-L5 double-segment degeneration was developed to compare transforaminal lumbar interbody fusion (TLIF)-based pedicle screw fixation systems (PSFS) and Bioflex-based pedicle screw dynamic stabilization systems (PSDSS). Three interspinous process spacers, namely DIAM, Wallis, and Coflex-F, were implanted at L3-L4, and three pedicle screw diameters of 6.5, 5.5, and 4.5 mm were evaluated under flexion and extension to quantify screw-rod parameter sensitivity. The results showed that both TLIF- and Bioflex-based topping-off constructs reduced intradiscal pressure (IDP) and restricted excessive range of motion (ROM) at the transition segment, especially during extension, with a maximum L3-L4 IDP reduction of 39.49% compared with the degenerated model. Compared with fusion-based constructs, Bioflex-based PSDSS provided greater surgical-segment unloading, reducing L4-L5 IDP by 55.07% in extension and 25.30% in flexion. However, this motion-preserving effect was accompanied by higher pedicle screw stress sensitivity; in the 4.5 mm Bioflex model, the average L4 screw stress reached 15.62 MPa in flexion, representing a 51.71% increase compared with the 6.5 mm screw. In contrast, PSFS constructs showed greater stress variation in the rigid connecting rods. Overall, under the present modeling assumptions, Bioflex-based fully dynamic topping-off constructs showed more favorable disc unloading and transition-segment motion regulation than fusion-based configurations, but their biomechanical benefit should be balanced against diameter-dependent pedicle screw stability. Full article

Objective: To investigate the association between pelvic incidence (PI) and fixation failure following single-level transforaminal lumbar interbody fusion (TLIF) for low-grade spondylolisthesis and to identify risk factors for pedicle screw loosening. Methods: This retrospective study included 80 patients who underwent single-level TLIF and were divided into a high PI group (n = 40) and a normal/low PI group (n = 40). Radiographic parameters including PI, lumbar lordosis (LL), pelvic tilt (PT), sacra l slope (SS), listhesis magnitude, and PI-LL mismatch were evaluated pre- and postoperatively. Screw loosening and fusion status were assessed at 6, 12, and 24 months. Multivariate logistic regression analysis was performed to identify independent risk factors for screw loosening. Results: The high PI group demonstrated significantly higher screw loosening rates than the normal/low PI group at all follow-up time points, with a rate of 57.5% versus 28.2% at 24 months (p = 0.012). Fusion rates were comparable between groups. Multivariate analysis identified high PI and residual listhesis were independent risk factors for screw loosening (Odds ratio 1.05 and 1.35). PI-LL mismatch > 10° showed higher odds but were not statistically significant. Conclusions: High PI is associated with an increased risk of pedicle screw loosening after single-level TLIF. Careful preoperative assessment and postoperative monitoring may help reduce fixation-related complications. Full article

Biportal endoscopic (BE) spine surgery has gained increasing attention as a minimally invasive alternative to conventional spinal procedures, yet the distribution of procedural applications and anatomic targets within influential BE-specific publications has not been clearly synthesized. This study aimed to synthesize influential publications on BE spine surgery to describe the evolution of procedural applications, anatomic focus, and clinically relevant themes reflected in the literature. A comprehensive search of the Web of Science database was performed using terms related to biportal and multiportal endoscopic spine techniques. Influential articles were identified using citation frequency as a screening criterion, and relevant study characteristics, including publication year, authorship, institutional affiliation, geographic region, journal, and spinal region addressed, were extracted. Full-text screening confirmed inclusion of true biportal endoscopic spinal procedures and categorized the anatomical region and surgical technique addressed. Publications spanned 1997 to 2023, with a marked increase after 2018 and peak productivity in 2022. Influential publications were most frequently published in World Neurosurgery, with substantial contributions originating from South Korea, including work by Dae-Jung Choi. Most studies focused on lumbar procedures, primarily decompression techniques and transforaminal lumbar interbody fusion. Overall, this review highlights the rapid clinical growth of BE spine surgery, with influential literature emphasizing lumbar applications and underscoring the need for further research on outcomes, learning curves, and broader international adoption. Full article

Background: Autologous bone graft is widely used for lumbar interbody fusion but may increase operative time and donor-site morbidity. Gene-activated grafts combining an osteoconductive scaffold with pro-angiogenic signaling may provide comparable fusion without graft harvesting. The aim of this paper is to compare radiographic fusion and health-related quality of life after single-level transforaminal lumbar interbody fusion (TLIF) using a gene-activated octacalcium phosphate graft containing plasmid DNA encoding vascular endothelial growth factor (OCP/VEGF) versus an autologous bone graft. Methods: 200 adults undergoing first-time single-level TLIF for degenerative lumbar stenosis were allocated 1:1 to OCP/VEGF (n = 100) or autograft (n = 100), prospectively. CT-based fusion assessment and SF-36 outcomes were evaluated at 6 and 12 months follow-up. Results: At 12 months after surgery, mean fusion-zone density was 617.6 ± 180.9 HU in the OCP/VEGF group versus 599.8 ± 181.9 HU in the autograft group (mean difference 17.8 HU; p = 0.484). Complete fusion on qualitative CT grading occurred in 77% versus 73%, respectively (risk difference 4%; p = 0.583). SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) improved significantly from baseline in both groups (p < 0.001), without clinically meaningful between-group differences at follow-up. Revision surgery occurred in 3% versus 5%. Conclusions: In single-level TLIF for degenerative lumbar stenosis, OCP/VEGF produced radiographic fusion and patient-reported outcomes comparable to autograft at 12 months, supporting its use as an autograft-sparing alternative. Full article

Background/Objectives: Posterior cage migration is a clinically relevant complication after lumbar interbody fusion. Most reported risk factors are derived from open techniques, whereas evidence specific to minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is limited. We evaluated factors associated with cage migration and symptomatic retropulsion in a large MIS-TLIF cohort. Methods: We retrospectively reviewed 650 consecutive patients undergoing MIS-TLIF, comprising 1126 fused motion segments. Cage migration was defined as posterior displacement > 3 mm compared with early postoperative radiographs. Demographic, clinical, surgical, and radiographic variables were compared between segments with and without migration. Cases with migration were further stratified by revision requirement. Results: Cage migration occurred in 27 of 1126 levels (2.4%). Seven cases required revision surgery for symptomatic cage retropulsion, corresponding to a level-based incidence of 0.6%. More posterior initial cage placement was significantly associated with subsequent migration. Age, body habitus, smoking, diabetes, endplate violation, and multilevel fusion were not associated with migration. Among migration cases, male sex was associated with higher odds of revision, and no radiographic or mechanical parameter predicted progression from radiographic migration to symptomatic retropulsion. In revision cases, the migrated cage was removed via the original approach, followed by contralateral placement of a new interbody cage using a minimally invasive technique. Conclusions: In this MIS-TLIF cohort, posterior initial cage placement was the primary factor associated with cage migration, consistent with prior open-series findings. Progression from migration to symptomatic retropulsion was not explained by mechanical parameters alone, suggesting a multifactorial process. These findings underscore the importance of meticulous cage positioning during MIS-TLIF and provide practical insights for postoperative surveillance and revision decision-making. Full article

Background/Objectives: Transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are widely utilized techniques for degenerative lumbar diseases. This study compared radiological and clinical outcomes of LLIF and TLIF in patients undergoing lumbar fusion. Methods: This non-randomized prospective observational study enrolled 117 patients (LLIF: n = 17; TLIF: n = 100), with an inherent imbalance in group sizes, who underwent one- or two-level lumbar interbody fusion. Primary outcome was segmental lordotic angle (SLA) at the operated level. Secondary outcomes included disc height, lumbar lordotic angle, sagittal vertical axis, and patient-reported outcomes. Assessments were conducted at baseline, 3, 6, 12, and 24 months. Linear mixed models analyzed longitudinal data. Results: Mean SLA improvement was not significantly different between the groups (LLIF: 3.04° vs. TLIF: 3.18°, p = 0.782). No significant differences were observed for disc height (p = 0.518), lumbar lordotic angle (p = 0.718), or sagittal vertical axis (p = 0.866). Patient-reported outcomes improved significantly in both groups. Linear mixed model analysis revealed no significant between-group effects for Oswestry Disability Index (p = 0.335) or low back pain (p = 0.069). TLIF showed higher rates of dural tears and wound complications, while LLIF had more sympathetic chain injuries and transient psoas weakness. Overall complication rates were comparable (p > 0.05). Conclusions: TLIF and LLIF demonstrate comparable radiographic and clinical outcomes at 24-month follow-up. Surgical technique selection should be individualized based on patient-specific anatomical and clinical factors, considering distinct approach-specific complication patterns. Full article

Background/Objectives: Postoperative opioid exposure after lumbar fusion remains a key clinical concern. Understanding which perioperative factors are associated with lower postoperative opioid use may help optimize recovery after minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF). This study aimed to determine if patients undergoing MIS-TLIF under spinal anesthesia (SA) showed lower postoperative opioid use compared to those undergoing MIS-TLIF under general anesthesia (GA). Methods: We retrospectively studied all adult patients (>18 years) undergoing 1- and contiguous 2-level MIS-TLIFs performed by a single surgeon. Patients undergoing the procedure under GA were compared to those undergoing the procedure under SA. Postoperative oral opioid use, up to 3 months post discharge, was collected. A 1:1 propensity score matching (PSM) protocol was implemented. Each outcome variable was initially assessed using univariate regression. Predictor variables with a p-value < 0.2 were included in the multivariate regression model. This was a retrospective, non-randomized study, and residual confounding cannot be excluded despite PSM. Results: The matched groups (n = 50 in each group) did not differ significantly depending on demographics or levels fused. Before regression, mean number of postoperative opioid prescriptions (p = 0.03), mean total operating room (OR) time in minutes (p < 0.01), and median length of stay (LOS) in days (p = 0.03) were significantly different. Multivariate regression showed that the GA group received 216.5 more total morphine milligram equivalents than the SA group (95% CI = 0.7–432.2, p = 0.049). The days of opioid use were higher in the GA group by 3.8 days (95% CI = 0.5 to 7.1, p = 0.025). On multivariate regression, LOS in hours was greater in the GA group by 14.1 h (p = 0.042). Conclusions: SA is an effective anesthetic modality for spinal surgery with the advantages of reduced postoperative opioid use, reduced OR time, and shorter LOS compared to GA. Full article

Background: Biportal endoscopic transforaminal lumbar interbody fusion (BESS-TLIF) is an emerging minimally invasive technique. This study aimed to evaluate the two-year radiological fusion outcomes of single-level BESS-TLIF using a specific banana-shaped, porous titanium interbody cage. Methods: This retrospective study reviewed 51 patients who underwent the specified procedure. The primary endpoint was the radiological fusion rate, assessed by computed tomography (CT) over 24 months using a three-grade system. Factors influencing fusion, particularly bone graft composition (demineralized bone matrix [DBM] only vs. DBM with I-factor), were also analyzed. Results: The final complete fusion rate at two years was 96.1% (49/51; 95% Confidence Interval (CI), 86.5–99.5%). Bony fusion occurred predominantly in the posterior and intracage regions. The only significant factor influencing fusion was the bone graft material. The ‘DBM with I-factor’ group achieved complete fusion significantly faster than the ‘DBM only’ group (log-rank test, p < 0.001), with a higher final fusion rate (100% vs. 83.3%, p = 0.045). Conclusions: Single-level BESS-TLIF using a banana-shaped, porous titanium cage provides favourable two-year radiological fusion rates. The selective addition of I-factor as an osteoinductive supplement can significantly accelerate the time to achieve solid arthrodesis. Full article

Reconstruction of large and complex hard tissue defects remains a major clinical challenge, as conventional autografts and allografts are often limited in availability, biological compatibility, and long-term efficacy, particularly for extensive defects or poor bone quality. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a potent osteoinductive factor capable of initiating the complete cascade of bone formation. However, its clinical use is restricted by dose-dependent complications such as inflammation, ectopic ossification, and osteolysis. This review synthesizes current evidence on the safety profile of rhBMP-2 and examines strategies to enhance its therapeutic index. Preclinical and clinical data indicate that conventional collagen-based carriers frequently cause rapid burst release and uncontrolled diffusion, aggravating adverse outcomes. It is noteworthy that low doses of rhBMP-2 (0.5–0.7 mg/level in anterior cervical discectomy and fusion (ACDF) or 0.5–1.0 mg/level in transforaminal lumbar interbody fusion (TLIF)) provide the optimal balance of efficacy and safety. Advanced biomaterial-based platforms, such as bioceramic–polymer composites, injectable hydrogels, and 3D-printed scaffolds, enable spatially and temporally controlled release while maintaining osteogenic efficacy. Molecular delivery approaches, including chemically modified messenger RNA (cmRNA) and regional gene therapy, provide transient, site-specific rhBMP-2 expression with reduced dosing and minimal systemic exposure. By integrating mechanistic insights with translational advances, this review outlines a framework for optimizing rhBMP-2-based regenerative protocols, emphasizing their potential role in multidisciplinary strategies for reconstructing complex hard tissue defects. Full article

Background/Objectives: Utilization of polyetheretherketone (PEEK) cages for spinal fusion has surged in the U.S., yet comprehensive comparisons evaluating its postoperative effectiveness with alternative materials remain limited. This systematic review investigates the efficacy of PEEK cages against traditional fusion materials across various surgery types, elucidating PEEK’s impact on fusion rates, postoperative outcomes, and long-term success. Methods: A systematic search of PubMed, CINAHL, Scopus, Embase, and Web of Science was conducted through 14 October 2024. Included studies were randomized controlled trials (RCTs) comparing PEEK cages with titanium, silicon nitride, and metal-coated PEEK cages for anterior cervical discectomy and fusion (ACDF), posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF). Article quality was assessed using GRADE criteria. Results: From 288 initially screened articles, 25 RCTs involving 2046 patients (mean follow-up 23.1 ± 18.2 months) met inclusion criteria and were determined as moderate (n = 21) or high (n = 4) quality. Fusion rates by cage material for PEEK (n = 1041), Ti-PEEK (n = 291), and titanium (n = 53) were 85.63 ± 18.00%, 80.05 ± 19.9%, and 92.75 ± 11.31%, respectively. In ACDF, titanium cages achieved higher fusion rates than PEEK (100% vs. 94%). In PLIF and TLIF, coated PEEK outperformed uncoated PEEK (75% vs. 71% and 94% vs. 84%, respectively). Uncoated PEEK achieved fusion rates of 94.04 ± 5.04% for ACDF, 71.21 ± 21.93% for PLIF, and 83.50 ± 24.66% for TLIF, with titanium outperforming PEEK in early fusion outcomes. Coated PEEK demonstrated potential improvements in fusion rates over uncoated PEEK in PLIFs and TLIFs. Conclusions: Selection of cage material for spinal fusions should be tailored to surgical requirements and patient needs. While titanium and PEEK are effective, their performance varies across contexts. New materials and surface modifications may enhance these outcomes further, warranting future research in long-term studies and development of novel materials. These findings can help surgeons choose cage materials according to procedure type, patient characteristics, and imaging needs. Full article

Introduction: Currently, static interbody cages are the gold standard for achieving solid arthrodesis in the spine, enhancing segmental stability, obtaining neuroforaminal decompression, and improving as well as maintaining segmental lordosis. It is well known that restoring sagittal balance and segmental lordosis is crucial for long-term outcomes in lumbar spine fusion. For some cases, expandable interbody cages are emerging as an alternative to static cages. This study aims to evaluate the radiographic outcomes and complications of standard open transforaminal lumbar interbody fusion (TLIF). Methods: A standard open TLIF procedure using expandable cages was performed at 1 to 3 levels in 71 patients (129 levels in total), with a follow-up of two years. All patients underwent radiological assessments preoperatively, immediately postoperatively, and at one and two years postoperatively. Radiological evaluation was conducted using standing lateral X-rays. Results: Segmental lordosis (SL) increased significantly from the preoperative value (9.0° ± 3.6°) to 24 months postoperatively (15.4° ± 3.0°), with improvements maintained throughout the 24-month follow-up period (p < 0.001). Similarly, anterior disc height (ADH), posterior disc height (PDH), and foraminal height (FH) each increased significantly from preoperative to immediate postoperative measurements, and these gains were maintained over the two-year follow-up (p < 0.001 each). Lumbar lordosis increased significantly from the preoperative value (41.9° ± 10.5°) to the immediate postoperative period (45.7° ± 10.8°); however, this improvement decreased slightly at the one- and two-year follow-ups. No revisions were required for cage-related complications. One patient experienced a surgical site infection, and two patients had mechanical complications (screw loosening and proximal junctional kyphosis). Conclusions: Expandable interbody cages enable excellent restoration and maintenance of disc height and segmental lordosis in a standard open TLIF procedures at two-year. Achieving these outcomes depends on several factors, including proper preparation of the vertebral endplates, accurate cage placement and expansion, posterior facet osteotomy, and the application of posterior compression prior to final fixation. These steps are essential to fully maximize the potential of expandable cage technology. Full article

Objective: Bilateral facetectomy (BF) within minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) remains debated regarding its advantages over unilateral facetectomy (UF) in restoring segmental lordosis, addressing spondylolisthesis and decompressing both neural foramina. The evidence is limited. We sought to determine the benefits of contralateral facetectomy on radiographic and clinical outcomes. Methods: We conducted a single-center retrospective analysis on patients with lumbar degenerative disease who underwent single-level percutaneous instrumentation and MI-TLIF with either UF or BF. Plain radiographs, CT and MRI were utilized for comparative radiographic analysis. Various intraoperative and clinical parameters were evaluated to assess surgical effort and clinical outcomes. Results: We included 81 UF and 23 BF cases; complete radiological data were available for 27 and 13 patients, respectively. Both techniques demonstrated a comparable increase in segmental lordosis (UF 2.1° ± 5.3° vs. BF 4.3° ± 5.4°, p > 0.1), which is below the study’s minimum detectable effect (MDE ≈ 5.1° at 80% power). Spondylolisthesis reduction was similar, with UF achieving a mean of 2.8 ± 2.2 mm and BF 2.4 ± 1.9 mm (p > 0.1). Mean posterior disc height did not differ significantly between groups (p > 0.1). The mean intraoperative blood loss was significantly higher with BF (803 ± 347 mL) compared to UF (437 ± 207 mL, p < 0.001). The mean duration of surgery was significantly longer for BF (240 ± 48 min) compared to UF (197 ± 37 min, p = 0.001). Conclusions: This study found no evidence of a large advantage of BF over UF in restoring segmental lordosis, spondylolisthesis and posterior disc height in monosegmental MI-TLIF surgery. Given the higher blood loss and longer operative time observed with BF, its use should be selective for specific indications. Full article