Search Results (335)

The development characteristics of primary fractures in coal serve as a prerequisite, influencing reservoir stimulation outcomes. The propagation of experimentally induced tensile cracks in the reservoir is closely related to the coal’s tensile fracture properties and the distribution of natural fractures. The effectiveness of reservoir stimulation directly determines the productivity of coalbed methane (CBM) wells, with clear variations in natural fracture development observed across different macroscopic coal components. Therefore, accurately evaluating the tensile fracture characteristics of different macroscopic coal components and the interaction patterns between experimentally induced and natural fractures is of great importance for deep CBM resources. This study focuses on vitrain, clarain, and durain from the deep #8 coal seam in the Daning-Jixian Block, located in the southern part of the Jinxi Flexural Fold Belt on the eastern margin of the Ordos Basin, which exhibit varying degrees of natural fracture development. Using the Brazilian splitting test and the centrally grooved three-point bending test, the tensile strength and Mode I fracture toughness of different macroscopic coal components were investigated. The study reveals the propagation behavior of pure tensile cracks and the resulting fracture network morphology in coal specimens with developed natural fractures. The presence of natural fractures reduces the tensile strength and fracture toughness of coal while increasing its brittleness. Compared to durain specimens (with average tensile strength of 2.09 MPa and fracture toughness of 0.338 MPa·m⁰·⁵), vitrain (avg. 0.92 MPa, 0.234 MPa·m⁰·⁵) and clarain (avg. 1.40 MPa, 0.185 MPa·m⁰·⁵) exhibit clearly lower tensile strength and fracture toughness, along with more pronounced brittle characteristics. Differences in geomechanical parameters among macroscopic coal components lead to distinct fracture behaviors: high-strength, high-fracture-toughness durain specimens require higher pressure to initiate fractures, which then propagate in a relatively regular manner; in contrast, low-strength, low-fracture-toughness vitrain and clarain fracture more easily, but their fracture paths are clearly influenced by natural fractures, promoting the formation of complex fracture networks. This study quantitatively characterizes the deflection and arrest behavior of experimentally induced tensile cracks interacting with dense natural fractures, providing a mechanistic basis for understanding fracture network complexity in deep coal. Full article

The Block MZ features tight reservoir physical properties and poor interlayer connectivity, making conventional injection-production patterns ineffective for formation energy supplementation. Although high initial production can be achieved after fracturing, stable production is difficult to maintain, resulting in a low ultimate recovery factor. To improve reserve utilization, two rounds of well pattern infilling and well adjustment have been implemented in the block, reducing the well spacing from the original 400 m to less than 50 m. The reservoir development has experienced three stages: depletion development, water huff and puff, and water flooding combined with fracturing. Nevertheless, the current recovery degree remains only approximately 7.0%. No obvious high-pressure main fractures are identified during the drilling, logging, and fracturing operations of infill wells, indicating that a large amount of remaining oil within the well spacing of 50–100 m has not been effectively produced. To further enhance the recovery factor and remaining oil producing degree of the mature tight oil reservoir in Block MZ, a novel combined fracturing technology dominated by pre-CO₂ injection, temporary plugging and diversion, and volume fracturing is innovatively proposed with the well group taken as the overall production enhancement unit. This technology effectively improves fracture complexity and expands the CO₂ sweep volume. Field application results demonstrate that the proposed technology can not only boost the production of a single well but also realize collaborative production enhancement of the entire well group. Compared with the conventional volume fracturing adopted in the early stage, the effective influencing radius of the well group is expanded from 50–150 m to 200–350 m, and the number of affected wells increases from 4 to 6–7. The average daily oil increment per well in the initial 90 days rises from 2.4 t/d to 8.1 t/d, and the average cumulative oil increment per well during the natural flow stage increases significantly from 67 t to 692 t. The remarkable production enhancement effect provides a novel technical approach for EOR (enhanced oil recovery) in mature tight oil blocks. Full article

Natural-fracture connectivity substantially influences hydraulic-fracture interaction with pre-existing discontinuities, but its quantitative role in fracture-network propagation remains insufficiently constrained. In this study, a coupled LEFM–cohesive-zone hydraulic-fracture propagation model was developed by combining crack-tip deflection criteria, traction-separation damage evolution and fluid–solid coupling. True triaxial hydraulic-fracturing experiments were conducted on artificial fracture networks with I-, V-, Y- and X-shaped connectivity elements to evaluate the model response. The results show that connected natural fractures redirect hydraulic fractures under low horizontal stress differences, producing deflection angles of 30–50 degrees. When the stress difference exceeds 4 MPa, fracture growth becomes more strongly aligned with the maximum principal stress direction. In the true triaxial tests, the total number of connected natural fractures increased from 14 in the I-shaped network to 17 and 21 in the Y- and X-shaped networks, corresponding to increases of 21.4% and 50.0%, respectively. X-shaped networks showed the strongest sensitivity to stress difference and injection rate, while higher elastic modulus reduced fracture width and promoted longer, narrower fractures. Scale-normalized comparisons based on image-derived experimental measurements showed that the predicted propagation length, fracture width and connected-fracture number followed the experimental trend from I-shaped to Y-shaped and X-shaped networks, with relative errors within 7.1% and a mean absolute percentage error of 4.8%. These findings suggest that fracture topology strongly influences pressure transmission and multidirectional activation in the tested models, whereas field-scale extrapolation requires three-dimensional validation and transport analysis. Full article

The development of potash deposits is generally accompanied by large losses of minerals in the subsurface. The main reason for these losses is the use of a room-and-pillar mining system, where left pillars hold the overlying rock strata and aquifers located above the productive seams. Over time, the bearing elements of the mining system begin to deteriorate, leading to a loss of continuity of the water-protective stratum, the formation of water-conducting fractures, salt dissolution, and consequently, the flooding of the potash mine. The most effective method for solving production problems in the field of increasing mineral recovery and mine safety is the introduction of backfilling technology. The aim of the study is to identify the effect of backfilling on the stress–strain state of the rock mass in the vicinity of stopping and backfilling operations, to develop a technology for potash ore extraction with increased recovery, and also to solve the fundamental issue of the proposed technology, namely, the transport and property considerations of the backfill mixture. Numerical modeling methods and analytical derivations of calculation formulas for backfill mixture transport are used in the work. A comparison of dry, hydraulic, and hardening backfill mixtures is carried out. The study established that hardening backfill ensures a faster transition to the stage of mining the remaining reserves. A technology for pillar extraction with the leaving of technologically necessary narrow pillars is proposed, allowing for the safety of mining operations. Formulas are derived for calculating the required strength of the backfill based on the loading degree of the technological pillar. Transportability criteria are formulated, and a calculation procedure for pipeline transport parameters under gravity and gravity-pneumatic modes is developed. The proposed technology for potash ore extraction with hardening backfill allows for increased mineral recovery while maintaining safe conditions for undermining the water-protective stratum. Full article

At the same structural position within the northern part of Block K, the coalbed methane (CBM) wells in the 3^# and 15^# coal seams exhibit marked productivity disparities. This study integrates a correlation analysis of engineering parameters with dynamic diagnosis of production indicator curves to examine two dimensions: static engineering compatibility and dynamic seepage interference. The results show that the degree of matching between engineering parameters and geological conditions is a key factor controlling the productivity variation. The 3^# coal seam has favorable engineering performance, and boosting fracturing scale and drainage rate both help promote gas output. Compared with the 3^# coal seam, the 15^# coal seam has a notable deficiency in engineering compatibility: its effective horizontal section length and coal encounter rate decrease by 8.4% and 5%, respectively, while sidetracking frequency increases approximately fivefold; moreover, enlarging fracturing scale does not bring better gas results. Production indicator curves were established based on the relationship between cumulative water production per unit effective horizontal length and production pressure difference and were classified into upward-convex and downward-concave types. The resulting chart for exogenous water interference enables quantitative characterization of key metrics, including theoretical ultimate gas production, interference level, and gas production efficiency. The theoretical ultimate gas production of the 3^# coal seam reaches 69.454 m³/(d·m), over ten times that of the 15^# coal seam, but the critical interference threshold of the 3^# seam is lower than that of the 15^# seam. Most 3^# wells are stably located in the non-interference zone, indicating high production capacity and strong sensitivity to exogenous water interference. For the 15^# seam, the production indicator curves of most wells deviate toward the interference zone at an early production stage, reflecting strong exogenous water leakage recharge. Therefore, for this block, CBM development must shift from the traditional approach of blindly enlarging stimulation scale to geological compatibility and recognition of exogenous water interference. Full article

Overburden rotation and mining disturbance promote deep coal fracture and spalling, potentially inducing dynamic hazards, while the coal–rock thickness ratio largely governs the composite’s dynamic response and failure severity. Based on the geological conditions of a typical deep coal mine, SHPB tests were performed on coal–sandstone composite specimens with four systematically varied coal-to-rock ratios (C:R = 1:0, 2:1, 1:1, and 1:2). High-speed photography and the digital speckle correlation method (DIC) were integrated to capture displacement, strain, energy, and fragmentation fields throughout progressive dynamic compression. Experimental data revealed four findings: (1) Crack development follows a sequential evolution process of initiation, propagation, and failure. Higher impact air pressure accelerates crack development and coalescence, resulting in a higher degree of specimen fragmentation and fewer large blocks. Within the tested range of coal–rock ratios, an increase in the rock proportion accelerates coal fracture, which is attributed to the significantly higher density and hardness of rock compared to coal. (2) Energy evolution consistently follows three stages: absorption, accumulation, and dissipation. Under identical impact pressure, a higher rock ratio elevates equivalent stiffness and wave impedance, leading to monotonic increases in peak stress, peak strain, absorbed energy, and dissipated energy. (3) The fragmentation degree exhibits a pronounced dependence on impact pressure. Specifically, for the pure coal specimen (C:R = 1:0), when the impact pressure increases from 0.3 MPa to 0.7 MPa, the mass percentage of coarse debris (>30 mm) drops from 73.37% to 18.57%, whereas that of fine particles (<4 mm) rises from 15.69% to 35.24%. (4) Under identical impact conditions, a higher rock proportion leads to increasing trends in all measured indicators, including peak stress, strain, and energy accumulation and dissipation, which are consistent with the superior mechanical properties of the rock. Based on these observations, it can be inferred that the wave impedance mismatch and stiffness ratio at the coal–rock interface play a key role in controlling stress wave transmission/reflection and strain incompatibility; however, the individual contribution of each factor warrants further dedicated investigation. Full article

The paper is the first to highlight what appears to be a unique and unusual failure mechanism that is associated with cracks that nucleated from corrosion pits in aluminium alloy (AA) 7085-T7452 specimens that were tested under a variable amplitude load spectrum. In this study, cracks initially nucleated at corrosion pits and first grew as would be expected, namely at ninety degrees to the surface and perpendicular to the applied load. However, after reaching a depth of approximately 2 mm, these various Mode I cracks transformed into what can be best described as interlayer cracks with their surfaces at an angle of approximately ninety degrees to the initial fatigue crack surface. Analysis of the failures revealed that the maximum value of the stress intensity factor at which this phenomenon occurred, which we have defined as K_IL, was substantially less than the fracture toughness for this material. As such, failure was not due to classical Mode I failure, but rather due to K exceeding what we will term K_IL. Despite the unusual failures, it was found that, up to the point where this phenomenon occurred, the crack growth versus cycles histories could be reasonably accurately predicted using the small crack growth equation developed by the authors in a prior study on AA 7085-T7452 specimens with a fastener hole. Full article

Reinforced concrete (RC) structures are susceptible to crack initiation and propagation during service, making accurate numerical simulation of crack behavior essential for assessing structural durability and safety. Current numerical approaches for simulating concrete cracking include smeared/continuum approaches, extended finite element method (XFEM), phase-field methods, and meso-mechanical models. In particular, smeared/continuum approaches (e.g., smeared crack and plastic-damage models such as CDP) indirectly reflect cracking through diffusive damage fields without providing explicit geometric information on crack locations and propagation paths. The XFEM module in commercial software is further restricted to first-order elements and encounters difficulties in simulating multi-crack propagation. These limitations indicate that further development of complementary crack-simulation frameworks is warranted. To this end, this paper presents a cracking simulation framework for RC members within the theoretical framework of the Specified Stress Method, adopting an adaptive degree-of-freedom strategy to balance computational accuracy and efficiency. The method introduces inelastic strain as an additional unknown and establishes a variational principle and the corresponding virtual work equation. Concrete cracking is described by specifying the stress on the crack plane to zero, so that the crack-surface stress remains zero after cracking, thereby avoiding the issue of damage reversibility and improving computational convergence. The method requires neither a predefined crack path nor remeshing after cracking. Unlike smeared/continuum approaches that rely on diffusive damage fields, the crack propagation paths, distribution characteristics, and evolution of multiple cracks are characterized through the spatial distribution of cracked integration points within the finite element mesh. In the present implementation, crack initiation is governed by the maximum tensile stress criterion, and a linear elastic constitutive model is adopted for concrete as a deliberate simplification to establish and verify the core computational mechanism of the framework. The proposed method was examined through three numerical examples. First, comparison with theoretical solutions confirmed the algorithm’s correctness in simulating cracking in heterogeneous RC tension members. Second, comparison with experimental results demonstrated qualitatively consistent crack propagation trends and load–displacement responses for RC beams under mixed-mode cracking; the calculated ultimate load of the plain concrete beam is lower than the experimental value, which is attributable to the use of the maximum tensile stress criterion without fracture energy considerations, and certain crack morphology deviations are observed due to the neglect of reinforcement–concrete bond-slip. Third, a multi-crack simulation of an under-reinforced RC beam showed that, whereas the XFEM module in ABAQUS captures only a single dominant crack near the mid-span, the proposed algorithm predicts multiple distributed cracking zones on both sides of the mid-span, qualitatively consistent with the typical flexural cracking behavior of under-reinforced RC beams; the algorithm also supports second-order elements (e.g., C3D20R) unavailable in the ABAQUS XFEM implementation. While the method is still in an exploratory stage, these results confirm the feasibility and potential of the Specified Stress Method as a complementary framework for RC cracking simulation, providing a basis for further development. Full article

Concrete readily develops cracks under service loads, which poses severe risks to the overall safety of engineering structures. In this work, the discrete element method (DEM) integrated with PFC2D 5.0 numerical software is adopted to construct a mesoscale concrete numerical model containing pre-existing internal fractures, and uniaxial compressive loading simulations are subsequently carried out. Unlike previous studies that predominantly examined isolated fracture parameters, this work systematically investigates the coupled effects of fracture inclination angle, length, and quantity on crack propagation mechanisms at the mesoscale, and for the first time establishes a quantitative relationship between microcrack spatial distribution patterns and macroscopic mechanical degradation. Parametric analyses are performed to quantify the influences of fracture geometric characteristics, including fracture inclination angle (30°, 45°, 60°), fracture length (short, long and extra-long), fracture quantity (4, 8 and 16), as well as the comparison between intact and fractured concrete specimens. The fracture quantities of 4, 8, and 16 are selected to represent low, medium, and high levels of initial defect density within the concrete matrix, corresponding to approximately 1%, 2%, and 4% of the total specimen area, respectively, thereby enabling a systematic investigation into the progressive deterioration of mechanical performance with increasing internal damage severity. The whole evolution process of crack initiation, crack propagation and ultimate failure patterns of concrete is systematically explored. Numerical results reveal that specimens with larger fracture angles exhibit higher compressive strength yet generate abundant newly formed microcracks, whereas low-angle prefabricated fractures are prone to triggering abrupt brittle failure. Specimens embedded with shorter fractures achieve superior mechanical strength and develop denser, more intensive microcrack distributions; in contrast, long pre-existing fractures drastically degrade compressive strength while limiting the generation of secondary cracks. Reducing the number of internal defects simultaneously improves compressive strength and expands the coverage range of the induced fracture network. Specimens with 16 prefabricated fractures deliver the weakest mechanical performance, owing to the excessively high initial defect density inside the matrix. In comparison with fractured samples, intact concrete without pre-set fractures achieves better comprehensive performance in terms of compressive strength, deformation compatibility and uniform microcrack development. A core conclusion drawn from this study is that the total quantity of microcracks cannot serve as a direct indicator to evaluate the damage degradation degree of concrete; instead, the spatial distribution pattern of microcracks dominates the deterioration level. Evenly scattered microcrack populations maintain relatively high residual strength, whereas the concentrated coalescence of microcracks into continuous penetrating macrocracks leads to an abrupt decline in structural load-carrying capacity. The findings of this research can provide theoretical references for stability evaluation and safety diagnosis of defective concrete structures in practical engineering. Full article

To address ecological security challenges in karst urban agglomerations, this study proposes a green infrastructure network (GIN) optimization framework that integrates geological characteristics with complex network theory. A fracture-modified minimum cumulative resistance (FM-MCR) model, coupled with an ant colony algorithm, was developed to enhance GIN extraction accuracy. Using a cascade failure model, the structural response of the GIN under simulated attack scenarios was systematically evaluated across four edge enhancement strategies, enabling spatial layout optimization. Network clustering and node centrality assessments were further applied to identify critical corridors and strategic nodes. Results identified 108 ecological sources, with Qiannan contributing the largest area (3141.97 km², 23.96% of the total), and 162 corridors in the original GIN. Among the four edge enhancement strategies, the low-degree-first (LDF) strategy significantly improved network robustness, decreasing percolation thresholds by 20.9%, 22.98%, and 16.99% under random, degree, and betweenness attacks, respectively. Network cluster analysis further delineated 45 GIN clusters, 19 critical corridors, and 11 strategic nodes, revealing cross-scale ecological hubs linking the Wumengshan–Daloushan corridor with Guiyang’s urban green wedge. This framework, characterized by geological correction, dynamic edge enhancement, and cluster-based management, offers a scientific basis for improving GIN resilience in karst regions. Full article

Carbonate gas reservoirs are characterized by strong heterogeneity and a complex combination of pores, fractures, and caves. The productivity of gas wells is controlled by many factors, including geology, development, and engineering factors. The traditional one-point productivity evaluation method is insufficient to accurately characterize the productivity differences in gas wells with different reservoir types. In this paper, the carbonate gas reservoir of the MK Formation in the HS 4 block is taken as the research object. Based on core characteristics, thin sections, dolomite content, and permeability data, the two main reservoir types, vuggy and fracture-vuggy, are systematically categorized. The influence of geological, development, and engineering factors on gas well productivity is analyzed using SHAP values. At the same time, to improve the accuracy and engineering practicability of gas reservoir productivity evaluation, the one-point productivity equation was refined, and open-flow capacity prediction charts for vuggy and fracture-vuggy reservoirs were constructed by combining the improved equation with the steady-state productivity equation. The results show that the dolomitization degree of vuggy reservoirs is lower than that of fracture-vuggy reservoirs, and the reservoir space types are mainly small dissolution pores or intergranular dissolution pores. The lithology of the fracture-vuggy reservoir is dolomite. The reservoir space of this type of reservoir is mainly composed of large dissolution pores and fractures, with a good matching relationship between fractures and pores. Based on the SHAP interpretation and analysis method, it is clear that cumulative water production, total acid fracturing fluid volume, gas-layer thickness, and porosity are the main factors affecting gas well productivity. Among them, the influence of cumulative water production and total acid fracturing fluid volume is the most significant, indicating that changes in the gas-water relationship and the effect of acid fracturing factors during development have a greater impact on gas well productivity. Based on the improved one-point productivity equation and the steady-state productivity equation, the open-flow prediction chart of vuggy and fracture-vuggy reservoirs is established. In predicting the gas well productivity of medium-deep reservoirs, with reconstruction scale and geological conditions similar to those of the HS 4 block, the chart’s predictions are in good agreement with field gas test and production test results. The single-well prediction error ranges from 2.2% to 6.5%, with an average error of 4.3%, indicating that the established chart has good applicability and predictive reliability. The research results can provide a theoretical and technical basis for reservoir classification evaluation, reasonable production allocation optimization, and new-well productivity prediction for carbonate gas reservoirs in the HS 4 block. Full article

The mechanical behavior of bamboo scrimber dowel-bearing under sustained loading was investigated via the Stepped Isothermal Creep Deformation (SICD) method using a 30-ton multi-field coupling system, with the test conducted over a duration of 51.5 h. Experimental results revealed three typical failure modes: material failure, local compression failure, and crushing failure. The damage degree increased linearly with stress level. SEM microstructural analysis further indicated that failure originated from progressive fracture and bending of fiber bundles, as well as layer compression and cracking induced by mechanical loading. The deformation process of bamboo scrimber dowel-bearing under sustained loading comprises four distinct stages, namely short-term deformation, initial creep, stable creep, and divergent creep. The divergent creep stage manifests exclusively at stress levels of S_L = 0.6, while at lower-stress levels, S_L = 0.2 and S_L = 0.4, only the first three stages are observed within the 51.5 h test duration. In addition, a preliminary analysis was conducted on the stiffness and strength reduction in bamboo scrimber dowel-bearing under sustained loading. These research findings elucidate the mechanical behavior of bamboo scrimber dowel-bearing under sustained loading, providing preliminary insights to inform future durability assessment and design methodology development for bamboo scrimber joint connections. Full article

Deep coal reservoirs commonly exhibit strong multiscale heterogeneity, which directly affects coalbed methane (CBM) storage, diffusion, and flow. In this study, deep No. 8 coal samples from the Daning–Jixian block, Ordos Basin, were comprehensively and quantitatively characterized using low-pressure CO₂ adsorption, low-temperature N₂ adsorption, mercury intrusion porosimetry (MIP), and nuclear magnetic resonance (NMR). A method-constrained calibration framework was developed to assign reliable fractal dimensions to different pore-size intervals and to calculate a volume-weighted comprehensive fractal index. The scale-dependent pore structure was evaluated, and its relationships with coal quality, maceral composition, and maximum vitrinite reflectance (R_o,max) were analyzed. The results show that deep anthracite has a trimodal pore-size distribution, with micropores dominating both specific surface area and pore volume. Fractal behavior is strongly scale-dependent, and calibrated full-pore-size fractal dimensions provide a more reliable measure of reservoir heterogeneity than single-method interpretations. Pore development and heterogeneity are closely associated with coalification degree, coal quality, and maceral composition. Ash tends to inhibit pore development, whereas fixed carbon and vitrinite promote micropore development; inertinite mainly contributes to macropores and fractures. These findings provide a quantitative basis for evaluating pore-structure heterogeneity and optimizing deep CBM reservoir development. Full article

Cemented natural fractures are widely developed in unconventional reservoirs and play a key role in controlling hydraulic fracture propagation and fracture network evolution. However, their mechanical effects are often oversimplified in conventional numerical models, limiting the reliability of fracture prediction. A numerical framework was established to investigate hydraulic fracture propagation in reservoirs containing cemented natural fractures. Cementation effects are quantitatively characterized using two parameters—cementation degree ($C_d$) and cementation strength ($C_s$)—representing the filling condition and interfacial resistance of natural fractures. Based on this formulation, both single-fracture and multiple-fracture models are constructed to analyze the influence of cementation properties and fracture density on fracture propagation. The results show that $C_d$ mainly controls fracture activation and propagation mode. Lower $C_d$ promotes fracture diversion and branching, whereas higher $C_d$ favors fracture penetration through the interface. $C_s$ governs interfacial resistance, with higher $C_s$ leading to more stable propagation. Increasing fracture density enhances fracture network complexity but also intensifies stress interference, affecting propagation stability and connectivity. These findings provide mechanistic insights into the role of cemented natural fractures in hydraulic fracturing and may support a more reliable interpretation of fracture propagation behavior in naturally fractured reservoirs. Full article

Objective: Perform endoscopic surgery for radiculopathy caused by compression fractures and evaluate the results. Methods: A total of 20 patients who underwent biportal endoscopic foraminotomy and unilateral screw fixation using a dynamic rod for radiculopathy secondary to osteoporotic compression fractures were included in this study. All surgeries were performed between July 2021 and January 2025. Patient demographic data, operated level, length of hospital stay, intraoperative blood loss, and operative time were reviewed. Radiological follow-up included assessment of segmental kyphosis, scoliosis, subsidence, and adjacent-level fractures. Complications and pain patterns—separately evaluated for back pain and radiculopathy—were assessed using the visual analog scale (VAS) preoperatively and during follow-up. Only single-level cases were included. Patients with infections, significant stenosis, instability, tumors, prior revision surgery, multilevel pathology, or ambiguous symptoms were excluded. Results: The mean age of the patients was 78.8 years (range, 69–89 years), reflecting an elderly cohort. The mean follow-up period was 13.0 ± 11.9 months (range, 1–41 months). The mean operative time was 164.8 ± 25.7 min, and the mean hospital stay was 10.2 ± 4.6 days (range, 4–25 days). The mean intraoperative blood loss was 126.5 ± 77.6 mL (range, 50–400 mL). One female patient developed postoperative pneumonia, which resolved after appropriate treatment; no other medical complications were observed. Radiculopathy improved significantly immediately after surgery and continued to improve during follow-up. Back pain also improved, but tended to persist to a mild degree. Radiologic evaluation revealed no significant changes in segmental lordosis, and there were no cases of subsidence, scoliosis, or symptomatic screw loosening during the available follow-up period. Conclusions: Biportal endoscopic foraminotomy with unilateral screw fixation may be an effective solution for radiculopathy caused by compression fractures. Full article