Set Of Blades Research Articles

Wear and Damage Study of Straw Chopper Knives in Combine Harvesters

Most of the biomass of cereal straw is chopped and left on the field as organic fertilizer, but its conversion into fertilizer depends on the quality of chopping, which is influenced by the wear of the chopping blades. The aim of the study was to determine the influence of the contamination of the cereal straw on the wear of the combine chopper blades. The study was conducted during the harvest in 2022, when 30 ± 1% of the grain was lodged and contaminated with abrasive soil particles (poor conditions), and in 2023, when the straw was unlodged and clean (excellent conditions). Six sets of blades with different mechanical and geometric properties were selected. The results showed that the wear ranges were very different: 1.47–2.99 g/100 ha in 2022 and 0.72–2.14 g/100 ha in 2023. For micro-abrasive wear, the hardness of the blades (349–568 HV) and the cutting edge angle (20°–29°) were important factors of their wear resistance. When the clean straw was chopped, the influence of the blade hardness and cutting edge angle on wear was not significant, and the wear was less. The wear of the blades had a sinusoidal character, which was related to the position of the blades on the chopping drum. This character depends on the design of the chopper and not on the straw quality.

The Underwater Berlin Research Turbine: A Wind Turbine Model for Wake Investigations in a Water Towing Tank

The design of a three-bladed horizontal axis research wind turbine for wake investigations is described. The turbine has a rotor diameter of 1.3 m and will be operated in a large water towing tank at a submergence depth of 2.5 m, yielding 3.3 % blockage. The test rig is configured to allow for underwater-stereo-particle-image-velocimetry measurements of the near and the far wake at chordwise Reynolds numbers approaching 700 000. The low-Reynolds number airfoil SG6040 is selected to constitute the rotor blades. Cavitation-free operation is assured by assigning a rated angle of attack of 1°. The blades are designed to maintain a constant circulation along the blade span and to minimize tip deflections. The blade pitch angles are adjustable. Various blade designs, with and without passive flow control devices, can be tested by replacing individual blade sections. This eliminates the need for multiple sets of blades. Sensors for acquiring the turbine’s thrust, torque, rotational speed, the azimuthal positions of the blades, and the imposed blade root bending moments are incorporated into the design. The wind turbine simulation suite QBlade is utilized to simulate the turbine characteristics. A model of the entire test rig is derived, representing its structural properties. Results from the analytical verification of the structural model are provided. QBlade is utilized to analyze the test rig design by imposing design loads and calculating the modal properties.

Rapid Composting Using a Novel Agricultural Waste Shredder

Agricultural waste causes social and environmental pollution, affecting global health. Converting agricultural waste to organic manure reduces the problems of pollution. Existing machine used in conversion has low efficiency in terms of throughput capacity and size reduction, leading to slow composting. This study focuses on the evaluation of a specially developed waste shredder for fast composting (maize straw). The machine was designed to handle substantial volumes of agricultural waste, operated at different speeds (i.e. 300, 600, 900, 1200 and 1500 rpm) and time (i.e. 0.5, 10, 1.5, 2.0 and 2.5 hr). The components of the machine included shredding drum equipped with three sets of blades, a feeding tray, sieve, engine seat and an outlet. Performance evaluation carried on the machine includes shredding efficiency and throughput capacity. A standardized Response surface methodology (RSM) was employed to maximize efficiency varying the operational speeds and shredding time. Results showed achieved maximum shredding efficiency of 91% and maximum throughput capacity of 585 kg/hr when the machine was operated at 1,500 rpm for 1.5 hr. In addition, the machine is portable, low energy and easy to operate for any agricultural waste.

Does the composition of meteoritic metal change with forging? An experimental study

AbstractThe use of meteoritic iron in the manufacture of human artifacts since the Bronze Age has been well documented, including the iron blade of Tutankhamun's dagger. Whereas the preservation of textures and mineral inclusions suggest relatively low temperature (<950°C) working of meteoritic metal used in artifacts, higher temperature working—that is, forging—could have occurred, based on studies of Bronze Age slag. The extent to which the forging of meteoritic iron might change the bulk composition, especially the trace elements used for classification of iron meteorites, is largely unknown. Using electron microbeam methods (SEM and EPMA), and trace element analysis (ICP‐MS), we analyze metal obtained at different stages during the modern forging of a set of knife blades from fragments of the Gebel Kamil meteorite, and assess the degree to which bulk element composition, mineral inclusions, and textures are modified. We find that while forging does destroy the original texture and removes mineral inclusions, it does not significantly modify the trace elements typically used in iron meteorite classification, at least for the relatively Ni‐rich composition represented by Gebel Kamil. While we acknowledge that the modern method by which the knife blades were forged from Gebel Kamil would not have occurred in the Bronze Age, our results represent an upper temperature limit relative to the inferred conditions used in ancient forging. The identification of the meteorite (if still in existence) that was used for artifacts is feasible, based on our results and current literature on ancient meteoritic artifacts.

Modeling of electromagnetic propagation inside jet engine environment using statistical electromagnetic approach

In this paper, the distribution of the electromagnetic field inside a complex jet engine environment is analyzed using statistical electromagnetics. The jet engine environment is an extremely complex geometry and exhibits random behavior due to the presence of moving metallic parts. This renders traditional analytical and simulation modeling techniques highly inefficient. To address this issue, two different approaches are proposed to model the propagation characteristics of the jet engine environment. The first is an innovative dynamic system approach based on dynamic system simulation which is inspired by the analysis of mechanically stirred reverberation chambers. In the dynamic system simulation the dynamic system, which is characterized by the rotation of a distinct set of blades, is primarily studied through the simulation program. A dimension scaling method is also introduced along with the dynamic system simulation to solve the complex jet engine environment. In the second approach, a novel statistical excitation method is applied to develop an equivalent model for the dynamic jet engine system. The studied jet engine is considered as a static jet engine system without blade rotation (static blades), but with a random excitation.A small signal analysis method is used to integrate the static and dynamic system parameters to generate random excitation characteristics of the static system. The extracted electric field values from the dynamic jet engine simulation environment and the static system field values from the small signal analysis have been analyzed statistically to prove the statistical equality between the two systems. The numerical results of the static system model are presented and verified through comparison with finite element method simulation packages.

Performance Evaluation of Power Weeder with Different Blade Mechanism in Intra-row Weeding Operation

Aims: Weeding operation is one of the most laborious and time-consuming operation in agriculture. Weeds basically an unwanted plant which competes with crop for light, moisture, and nutrient along with lowering the overall yield. Mechanical weed control methods are preferred among all weeding methods due to many reasons such as timeliness, safety, drudgery and cost effective.
 Study Area and Duration: The experiment was conducted in the farmer’s field of Abhayapuri, Bongaigaon, Assam in the year 2021 to 2023.
 Methodology: This study employed a 5.75 hp self-propelled diesel engine with three blade sets—rotary, non-rotary, and a combination of both, designed for weeding in vegetable fields with row spacing up to 75 cm. One-way ANOVA analysis compared group means for statistical significance.
 Results: Results showed that the field efficiency (90%), fuel consumption (7.7 l/ha), cost of operation (Rs 1217.7 per ha) and plant damage factor (0.01%) was better for rotary blade than non-rotary and combined blade. Whereas effective field capacity (0.07 ha/h), performance index (155.7) and man-hour/ha (14.3) was better for non-rotary blade and the parameters such as depth (4.4 cm) and weeding efficiency (94.2%) was better for combined blade mechanism. From the one-way ANOVA analysis, it showed that blade mechanism showed significant difference on parameters like weeding efficiency, field efficiency, fuel consumption, effective field capacity, cost of operation, man-h/ha and performance index at p<0.05 and non-significant for depth and plant damage factor at P<0.05.
 Conclusion: Study concluded that for intra-row weeding operation, rotary blade along with non-rotary blade was suitable economically whereas combined blade was suitable for weeding performance only besides high cost.

New Urban Vertical Axis Wind Turbine Design

A different approach for enhancing the performance of a Vertical Axis Wind Turbines (VAWT) for the use in the urban or rural environment and remote isolated residential areas is developed in this study. Recently the small VAWT became more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. By adding a second set of blades (3 x 2=6 blades) that following the rules of biplane airplanes we aim to enhance the overall performance of the VAWT. The model has been made to operate at a maximum power in the range of the TSR between 2 to 2.5. The performances of the VAWT were investigated numerically and experimentally to justify the new proposed design.

Research on Vibration Response of Shrouded Blades Based on Contact State

The shrouded is widely used in vibration reduction of turbine blades. In this study, the damping characteristics of the shrouded blade in gas turbine were studied. Firstly, a finite element model of the shrouded blade was established, and the full set of blades was reduced to a single sector based on the principle of cyclic symmetry. The contact state of the contact surface of the blade at different interference and speeds was calculated based on the displacement extraction method. Secondly, a microslip friction contact model was established based on the contact state of the contact surface. The nonlinear vibration response of shrouded blades was calculated based on the harmonic balance method. The results indicate that the shrouded has excellent vibration reduction performance. The interference and rotational speed of the blade will affect the damping efficiency.

Spar Cap/Shear Web Debonding Under Fatigue Loading Studied On The DTU 12.6m Wind Turbine Blade

Understanding fatigue damage initiation and propagation of composite wind turbine blades is an essential step towards the design of reliable prognostic and health management systems (PHM) and to improve lifetime predictions. This study presents a numerical investigation of the debonding process in the spar cap/shear web region of a full-scale composite wind turbine blade under fatigue loading and presents the manufacturing approach for creating initial debondings. For this purpose, numerical simulations have been performed to design and specify the size and locations of artificial defects to provoke steady, controllable damage growth in the adhesive bondline between the rear shear web and cap region of the DTU 12.6m wind turbine blade under fatigue loading. Subsequently, these artificial defects are embedded into the manufacturing process of the composite wind turbine blade with the help of slip foils and partially perforated slip foils to create regions with no bonding, 30% and 50% bonding of the contact surfaces of the adhesive joint, respectively.The numerical predictions as well as the manufactured and instrumented blade sets the framework to subsequently execute experimental tests of damage growth in the adhesive joint of the bondline in order to compare numerical and experimental data. The experimental demonstration will allow to better understand the complexity of damage growth of composite structures under fatigue loading and the necessity of accurate numerical prediction tools for reliable prognostic health management systems.

Performance and Acoustics of a Stacked Rotor with Differential Collective Pitch

Performance and acoustics of a 1.108-m radius stacked rotor in hover with an axial spacing between the upper and lower rotors of 0.73 chords were measured. The differential collective pitch of the rotor system, de ned as half the difference between the upper rotor pitch and lower rotor pitch was varied along with the azimuthal spacing between the upper and lower blade sets. Coupled comprehensive analysis and acoustics simulations were conducted using the Rotorcraft Comprehensive Analysis System, the acoustic solver PSU-WOPWOP, and the Brooks, Pope, and Marcolini method implemented in ANOPP2. Increased sensitivity to azimuthal spacing was measured for large, negative differential collectives, resulting in a 76.5% change in total rotor thrust and a 46% change in total rotor power over 11.25 ° change in azimuthal spacing. The trends in individual and total system thrust were predicted with good accuracy, but the total power was overpredicted. Overall sound pressure level decreased by 3.5 dB at – 2° differential collective and 90° azimuthal spacing due to reduced broadband levels, indicating a possible quiet mode of operation for this type of rotor. By assessing the highest performance and lowest noise, an optimum rotor con guration was observed at an azimuthal spacing of – 45° and differential collective of 2°. Acoustic predictions captured tonal and broadband noise trends in most conditions. Conditions where broadband noise was underpredicted could be a result of vortex interactions not modeled by the broadband simulations.

Analysis of Contra-Rotating Brushless Integrated Flux-Modulation Machine With Open-Slot Structure for Wind Power Generation

This paper presents a contra-rotating (CR) brushless integrated flux-modulation (BIFM) machine with open-slot structure for wind power generation, termed CR-BIFM machine. The presented machine employs two contra-rotating rotors coupled with two sets of wind turbine blades, thus being able to capture more wind energy than conventional single-rotor wind turbines. Due to the dual flux-modulation effect and flux-bridge effect, the presented machine exhibits high torque/power density, making it suitable for direct-drive wind power generation without issues related to mechanical gearboxes. As two sets of windings share the same stator slots in the presented machine, the decoupling design of windings is systematically investigated from the perspective of air-gap modulated magnetic field, considering the influence of both stator and rotors. The advantages of the presented machine are comprehensively evaluated compared to the baseline machine, showing that the presented machine exhibits higher torque/power density, higher efficiency, higher power factor, higher PM utilization, and better vibration performance. Finally, a prototype is fabricated and tested to validate the analysis.

INVESTIGASI EFEK SOLIDITAS RUNNER TERHADAP PERFORMA TURBIN CROSSFLOW

The crossflow turbine is a popular type of hydropower generator used to convert water energy into electricity. It offers several advantages, including a simple design, reliable performance, and suitability for low-head water flows. This study investigates the effect of runner solidity on the performance of a crossflow turbine. The designed turbine will operate at a three-meter head with a flow rate of 41.55 litters and a runner speed of 300 rpm. The runner design is straightforward, using blades made from four-inch pipes for easy availability and simple manufacturing and repair processes. Variations in runner solidity are achieved by adjusting the number of blades. The investigation uses runners with 15, 20, 25, 30, and 33 blades, representing solidities of 11.7%, 14.6%, 17.5%, and 19.2%, respectively. The results show that the runner developed from a set of blades produced by four-inch pipes, operating under the designed conditions, achieves maximum performance with an efficiency of 81.42% at a solidity of 17.5%, or 30 blades

Design Methodology for a Low-Shear Rotating Swirler

The tubular dynamic hydrocyclone (TDH) holds great potential for the pre-deoiling of offshore oil platforms. However, the shear and turbulence in the flow field can cause the oil droplets, the dispersed phase in water, to break up when the swirling flow is produced by the swirler. A design method is proposed for the low-shear rotary swirler (LSRS) of TDH, the aim of which is to reduce the shear force and local turbulence during the fluid forming swirling flow. The blade setting angle of the LSRS is calculated based on the relative velocity vector between the fluid and the swirler. The distribution characteristics of the tangential velocity and turbulence in the TDH with LSRS are simulated by Computational Fluid Dynamics (CFD). The maximum stable droplet diameter is analyzed. The results show that the shear stress and turbulence energy dissipation rates are reduced by 74.6% and 68.5%, respectively, and that the stable droplet diameter is increased by more than 60%, compared to the conventional rotating swirler. In addition, a TDH prototype with LSRS was tested in an offshore oil field by continuous operation for more than 36 h. The average separation efficiency was 83%, and the average underflow oil concentration was 27 mg/L. The research also found that the drastic changes in the tangential velocity along the axial direction were critical to shear. Moreover, the results make up for the deficiency of the spatial variation of the tangential velocity in the dynamic cyclone separator.

Decohesion of a polyolefin overlay from a substrate high density polyethylene layer by impact induced stress waves

High-density polythene (HDPE) is difficult to separate from food packaging waste for recycling because the packaging occasionally has multilayer plastic labels attached. Solvents are employed in the current separation techniques to remove undesirable layers from HDPE substrates. The possibility of separating HDPE via the impact-delamination phenomenon was explored both theoretically and experimentally. Using the cohesive zone model (CZM), the decohesion of layers in a model two-layer laminate made of HDPE and LDPE layers was studied theoretically. According to this study, stress waves emerge and severely damage the adhesion between the layers as a cutting blade strikes the laminate at speeds greater than 40 m/s. The damage can be enhanced by increasing the strike velocity and the apex radius of the blade. These findings show that a novel plastic delaminator that can cut and delaminate the laminates simultaneously can be designed. The proposed machine will feature two sets of blades with varying edge apex radii. One set of blades can be designed to cause the most adhesion damage while the other blades cut the laminate. This unique combination of cutting and delamination operations has several benefits, including less solvent waste and downstream processes, greater environmental friendliness, and faster HDPE separation.Laminates from HDPE milk bottles were cut using a high-speed cutter-blender with six blades to test the predicted results. The cut HDPE flakes were separated pneumatically. According to FTIR analysis and SEM, only a trace of adhesive was present on the cut and separated HDPE flakes.

A new criterion for the instability threshold of a square tube bundle subject to an air–water cross-flow

In this paper, we investigate the fluid-elastic instability of a square tube bundle subject to two-phase cross-flow. A dimensional analysis is carried out, leading to a new criterion of instability. This criterion establishes a direct link with the instability thresholds in single-phase flows. In parallel to the dimensional analysis, experimental work is carried out to i) determine the instability thresholds in single-phase flows (new relation between the Scruton, Stokes and Reynolds number), ii) to test the validity of the two-phase flow instability criterion, derived from the dimensional analysis. The experiments are carried out on a square tube bundle (pitch ratio of 1.5) consisting on 5 rows of 3 tubes (plus two end-rows of half tubes). The central tube is mounted on two flexible blades allowing a vibration in the transverse direction only, whereas all the other tubes are rigid. The instability threshold in single-phase (water) flow is obtained from a method of direct measurement of the fluid-elastic forces, in which the motion of the central tube is imposed. The instability threshold in two-phase (air–water) flow is obtained from a method of indirect measurement, with an active system stability control, of the fluid-elastic forces, in which the central tube vibrates freely. Three sets of blades with different stiffnesses are tested to investigate the stability of the central tube. The criterion of instability is in very good agreement with air–water experiments, predictive for all homogeneous void fractions, and so for all flow regimes (identified in our experiments with an optical probe). This new criterion is of theoretical interest for the understanding of complex two-phase flow excitations, as well as of practical significance for the predictive analysis of industrial components.

Preliminary performance assessment from towing tank testing of a horizontal-axis turbine

Following the Norwegian government’s goal to be a ‘low emission society’ by 2050, there is a significant push to develop offshore renewable energy; principally offshore wind, but also wave and tidal stream. The MarinLab towing tank at the Western Norway University of Applied Sciences, Norway is 50 m long with a 3.0×2.2 m section and was inaugurated in 2016 as an educational and research facility, supporting local industry to achieve a low-carbon transition.
 To advance knowledge of aero- or hydrodynamic interaction of future turbines for both wind and tidal stream energy, a model scale test-bed horizontal axis turbine has been developed. This turbine will enable testing of rotor diameters typically in the range of 500-600 mm. The turbine is instrumented with a torque-thrust sensor of 5 Nm/100 N capacity, custom-manufactured by Marin in the Netherlands. The turbine is speed regulated via a 4096 counts angular encoder connected to a 200 W Maxon EC-i brushless motor.
 Before testing new rotor geometries, a benchmarking study is being undertaken with an existing known geometry. The benchmark rotor has diameter, D=700 mm and employs the same NACA 63418 airfoil as Mycek et al. (2014), allowing comparison. Unlike Mycek et al. (2014), the nacelle has a nominal diameter of 90 mm and length 760 mm. The size of the rotor risks exceeding the capacity of the torque sensor, such that maximum tow-speed is limited to 0.8 m/s. The benchmark blades are machined from solid aluminium in a four-axis CNC milling machine, following a method similar to Payne et al. (2017). Due to machining limitations, the minimum trailing edge thickness is specified as 0.2 mm. The final surface finish is achieved by manual polishing, and the final dimensions, quantified using a Hexagon ROMER Absolute laser scanner, are found to be within ±0.2 mm accuracy. Future blade sets will typically have a smaller diameter, allowing for 3D printing and consistency of surface finish.
 A blade-element momentum model has been run with Prandtl tip and hub losses and 0° pitch (Fig. I). Lift and drag coefficients were calculated for a range of chord Reynolds numbers using XFOIL, for angles of attack between -5 to 16° and extrapolated to ±180° with Viterna’s method. Due to difficulties in estimating laminar-turbulent transition around critical Reynolds numbers, there is uncertainty in the XFOIL coefficients. At peak TSR, the chord-based Reynolds number is approximately 280k at 3/4 span. Curves for both Rec =250k (solid) and 500k (dashed) with Ncrit = 9 are presented, showing a significant drop in performance for lower Reynolds numbers, due to a collapse in Cl/Cd. Initial tests were conducted in near- zero ambient turbulence, though passive turbulence grids are available for future testing. Reasonable agreement on CT is observed when corrected for blockage according to Bahaj (2007), and further assessment will provide results on CP, tower loads and wake recovery.

Optimized Design of a Multistage Centrifugal Pump Based on Volumetric Loss Reduction by Auxiliary Blades

Throat ring leakage is a major factor deteriorating the performance of multistage centrifugal pumps. This paper focuses on the optimization of multistage centrifugal pumps by incorporating the principle of the Tesla valve and adding an auxiliary set of blades to the impeller body. By changing the direction and magnitude of the leaking fluid’s flow, the leakage volume of the impeller throat ring is reduced. The study results demonstrate that the experimental error in head calculation with numerical simulation at the optimal working condition was 0.65%, verifying the accuracy of the numerical simulation method. The leakage volume of the throat ring decreased by up to approximately 28.99% compared to the original structure, which significantly increased the pump’s head and overall efficiency. Near the optimal operating point, the pump’s head and overall efficiency increased by approximately 8.1% and 8.7%, respectively. The larger the flow rate, the greater the improvement in the pump’s head and total efficiency. Near high-flow operating conditions, the pump’s head and overall efficiency increased by approximately 116.45% and 110.84%, respectively. The auxiliary blade structure introduces a non-contact seal which, compared to traditional seal structures, improves seal life and reduces seal costs. Additionally, the auxiliary blades can shift the optimal operating point of the multistage centrifugal pump towards a higher flow rate, improving the pump’s delivery capability.

Design and comparative analysis of beater knife mechanism for mango pulp extraction

The purpose of this research work was to design, fabricate and evaluate an enhanced fruit pulp extraction unit to convert the available fruit into pulp to increase profitability and to limit post-harvest losses. This study introduced a newly developed mechanism with beater-type blades having serrated knives. As compared to the existing screw-type pulpers this newly developed pulping machine is quite lightweight, cheap, easy to fabricate, requires low maintenance, and has a low running cost. The major factors that were considered while planning included cost-effectiveness, manufacturing ease, high efficiency and user-friendly operation. The machine works by applying shearing and centrifugal forces on the fed fruits through an innovatively designed set of blades. The data like mass of fruits and residual waste, extracted juice volume and time taken for juice extraction were collected and used to calculate the key performance indicators (KPIs) which included juice yield, extraction efficiency and extraction loss of the unit. The mango types like Sindhri, Chaunsa and Langra were used and maximum average juice yield and extraction efficiency were obtained for Chaunsa variety at 600 rpm with 700-micron diameter sieve mesh size and 25 mm beater and sieve mesh clearance. The beater-type and screw-type pulpers have juice yield percentages of 63.40% & 34.56%, extraction efficiencies of 56.70% & 54.15%, power consumption of 1HP & 2.5HP and manufacturing costs of USD1275 & USD2000 respectively. The processing capacity of this pulp processing unit is 60-70kg/h.

Hoof Trimming as a Major Issue in Cattle Farming… Indian Scenario

Abstract: India has the largest number for cattle farming about 302.79 million, and as the part of managing the cattle health Hoof cutting is the major issue when it comes to taking care of cattle. Improper cutting of hoof can lead to harm to the cattle and it may sometimes turn into severe disease, in this case cattle may be prone to lameness. The cutting of hoof is done by traditional way by using tools like chisel, grinder, pincer etc. these tools have their own specific applications, but still it is used to cut hoofs, It is observed that there is no specific tool for cutting hoof of cattle and available tools not having tool Replacement. In literature review, researcher also neglected the issue and it is rarely found the development of new special tool for hoof cutting. So there is scope of working on this tool. Under this project activity, the designed and developed portable hand operated hoof cutter, new developed tool has the various blade settings adjustment which increase versatility of cutter, and it can cut 4”, 6”, and 8” length of hoof by using this cutter. The new developed cutter has 30% more efficiency compared to all the traditional cutting methods. This Project presents the design and fabrication of a hoof cutter for cattle. New Developed hoof cutter is designed to be efficient, safe, and user-friendly. The hoof cutter is fabricated using readily available materials that are easy to source and assemble. The tool is portable and easy to use, making it ideal for use in the field by farmers and veterinarians. The hoof cutter is tested to evaluate its efficiency and safety. The results showed that the hoof cutter is both efficient and safe to use

MP13-08 HOLMIUM LASER ENUCLEATION OF THE PROSTATE (HOLEP) OUTCOMES AFTER MINIMALLY INVASIVE SURGICAL THERAPIES (MIST) FOR BPH

You have accessJournal of UrologyCME1 Apr 2023MP13-08 HOLMIUM LASER ENUCLEATION OF THE PROSTATE (HOLEP) OUTCOMES AFTER MINIMALLY INVASIVE SURGICAL THERAPIES (MIST) FOR BPH Mark Assmus, Nick Dean, Matthew Lee, Jenny Guo, and Amy Krambeck Mark AssmusMark Assmus More articles by this author , Nick DeanNick Dean More articles by this author , Matthew LeeMatthew Lee More articles by this author , Jenny GuoJenny Guo More articles by this author , and Amy KrambeckAmy Krambeck More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003233.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The 2021 American Urologic Association benign prostate hyperplasia (BPH) guideline recommends several minimally invasive surgical therapies (MIST). We look to describe outcomes of individuals undergoing holmium laser enucleation of the prostate (HoLEP) after failing prior minimally invasive BPH procedures, specifically prostatic urethral lift (PUL), water vapor thermal therapy (WVTT), robotic waterjet treatment (RWT) or prostatic artery embolization (PAE). METHODS: We retrospectively examined patients within our IRB approved clinical database that underwent HoLEP over a 19-month period (March 2021 – Oct 2022). Patient demographics, surgical BPH treatments, operative variables, and perioperative courses were examined. Patients with a prior neurological diagnosis or prior bladder cancer were excluded from the analysis. Descriptive statistics, two-tailed T-Tests, and ANOVA were performed with SPSS (p<0.05). Although PAE is not an office-based procedure, due to its minimally invasive nature we included it in the MIST category. RESULTS: We identified 600 HoLEP patients who met inclusion criteria, with 24.2% (n=145) of patients having undergone a prior BPH procedure. Of these procedures, 31.7% (n=46) were MISTs including PUL (n=22), WVTT (n=11), RWT (n=3), and PAE (n=10) and the remaining 68.3% (n=99) of procedures were TURP (n=63) and photo-selective vaporization of the prostate (PVP) (n=36). Time from original treatment to HoLEP did not differ between MIST procedures (p>0.05), but was significantly shortened comparing MISTs to TURP and PVP (2.9 versus 6.8 years, p<0.01). Patients with a prior BPH procedure were older (72.4 versus 69.7 years, p<0.01) than those without a history of BPH procedures; however, there were no other differences in pre-operative patient variables or post-operative functional outcomes including catheter free status, anti-cholinergic requirements, and continence rates, or 90-day complications (all p>0.05). Patients with a prior PUL had a significantly worse morcellation efficiency (7.3 vs 9.0 grams/min, p=0.03) and required more sets of morcellator blades per case (1.3 vs 1.0, p=0.03) compared to other prior BPH treatments. CONCLUSIONS: Patients undergoing HoLEP after prior failed BPH surgery experienced equivalent outcomes to patients without prior BPH surgery. Patient functional outcomes after HoLEP were maintained regardless of prior treatment modality. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e176 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mark Assmus More articles by this author Nick Dean More articles by this author Matthew Lee More articles by this author Jenny Guo More articles by this author Amy Krambeck More articles by this author Expand All Advertisement PDF downloadLoading ...