Drilling Research Articles

Comparison of curved and straight tip radiofrequency cannula deflection in a ballistic model

BackgroundPercutaneous pain and spine procedures play an important diagnostic and therapeutic role in the treatment of various pain diagnoses. Accurate placement of needles or cannulae during these procedures is paramount to the success of these procedures. ObjectiveThe purpose of this study is to examine and quantify the amount of deflection of radiofrequency cannulae based on curved tip versus no curved tip, using a ballistic gel tissue simulant. Materials and methodsSix different types of cannulae commonly used for spinal and peripheral nerve ablations were selected, including 18, 20, and 22 gauge curved and straight radiofrequency cannulae. Ballistic gel samples were made in molds of 40 mm and 80 mm. Each cannula was mounted in a drill press to ensure accurate trajectory. ResultsCurved RFA cannula had increased deflection when compared to straight cannula for 18-, 20-, and 22-gauge cannulae at a depth of 40 mm. Curved RFA cannula had increased deflection when compared to straight cannula for 20- and 22-gauge cannulae at a depth of 80 mm. Overall, the mean deflection for a curved cannula increased 1.9x for 20-gauge cannulae and 2.5x for 22-gauge cannulae when compared to a straight cannula. ConclusionsFor interventionalists, understanding the effects of needle or cannula shape is crucial for accurate placement. When a procedure requires additional steerability, additional deflection up to 2.5x obtained by placing a bend in the needle or cannula tip should be considered.

Learning periodic skills for robotic manipulation: Insights on orientation and impedance

Many daily tasks exhibit a periodic nature, necessitating that robots possess the ability to execute them either alone or in collaboration with humans. A widely used approach to encode and learn such periodic patterns from human demonstrations is through periodic Dynamic Movement Primitives (DMPs). Periodic DMPs encode cyclic data independently across multiple dimensions of multi-degree of freedom systems. This method is effective for simple data, like Cartesian or joint position trajectories. However, it cannot account for various geometric constraints imposed by more complex data, such as orientation and stiffness. To bridge this gap, we propose a novel periodic DMP formulation that enables the encoding of periodic orientation trajectories and varying stiffness matrices while considering their geometric constraints. Our geometry-aware approach exploits the properties of the Riemannian manifold and Lie group to directly encode such periodic data while respecting its inherent geometric constraints. We initially employed simulation to validate the technical aspects of the proposed method thoroughly. Subsequently, we conducted experiments with two different real-world robots performing daily tasks involving periodic changes in orientation and/or stiffness, i.e., operating a drilling machine using a rotary handle and facilitating collaborative human–robot sawing.

Suicide by an Electric Power Drill and Spade Drill Bit: An Unusual Mechanism of Death.

Self-inflicted penetrating brain injuries with drills have been reported but are uncommon and typically involve the use of conventional drill bits. We report an unusual case of a 56-year-old man with a history of psychiatric illness who completed suicide using an electric drill and spade-type drill bit. Multiple superficial scalp and deeper bony injuries were sustained, although without breach of the dura, and death was not from brain injury, but secondary to venous air embolism related to entrainment of air into diploic vessels.

Numerical investigation of rock-breaking mechanisms and influencing factors of different PDC cutters during rotary percussion drilling

While drilling deep or ultra-deep wells in hard rock formations, there are significant problems such as easy wear of drilling cutters and a low rate of penetration (ROP), and rotary percussion drilling technology is one of the essential techniques for improving drilling efficiency. However, there is currently limited research on the compatibility of rotary percussion drilling tools, polycrystalline diamond compact (PDC) cutters, and hard rock formations. Considering the motion mechanism of rotary percussion drilling tools, a three-dimensional rock-breaking numerical model was established for different cutters (planar, axe-shaped, and triple-ridged) under impact loads. Penetration depths, cutting widths, and rock-breaking volumes of different cutters under static and dynamic load coupling were analyzed. Changes in tensile, compressive, and shear stresses during the cutter rock-breaking process were compared, revealing the different cutter rock-breaking mechanisms under impact loads. The cutter rock-breaking laws under different impact amplitudes and frequencies were analyzed quantitatively, and the differences in rock-breaking effects of different cutters under various geological conditions were assessed. The results indicated that cutter penetration depth during rotary percussion drilling could be increased by 16.04% compared to that during conventional drilling. Under the same impact load, the rock-breaking effects of different cutters on hard and soft rocks exhibited similar variation patterns. The penetration depth followed the order axe-shaped > triple-ridged > planar cutters, with an average tangential order of triple-ridged < axe-shaped < planar cutters. When drilling through hard rock, the average penetration depths of planar, axe-shaped, and triple-ridged cutters were 5.57, 6.06, and 3.91 mm, respectively. The average tangential forces were 670.57, 541.76, and 347.89 N, respectively. During the transition from soft to hard rock during drilling, the tangential forces of the planar, axe-shaped, and triple-ridged cutters increased by 8.41%, 3.21%, and 2.64%, respectively. The planar cutter experienced the most significant instantaneous tangential-force change and was more prone to impact damage. Increasing the amplitude of the axial stress waves helps enhance the penetration depth of the drill bit, whereas increasing the frequency of the stress waves can reduce the intensity of fluctuations during drill-bit penetration and increase drill-bit stability. The research results provide insights into optimizing drilling cutters and engineering parameters during rotary percussion drilling.

High-precision U-Pb geochronology for the Miocene Climate Optimum and a novel approach for calibrating age models in deep-sea sediment cores

Abstract Scientific ocean drilling cores recovered years ago (legacy cores), especially as recovered by rotary drilling, commonly show incomplete recovery and core disturbance. We present a novel method to date such cores by presenting the first high-precision U-Pb zircon ages targeting the duration of the Miocene Climate Optimum (MCO; ca. 17–14 Ma) from volcanic ashes at Ocean Drilling Program Site 1000 (on the Nicaragua Rise in the Caribbean Sea). We place these ages within a newly developed framework to address incomplete core recovery and use them to calibrate a high-resolution bulk carbonate δ13C and δ18O record. Our Site 1000 ages show that volcanism of the Columbia River Basalt Group (CRBG) large igneous province was coincident with the interval of greatest sustained MCO warmth at this site. However, if the CRBG were the primary driver of the MCO, our chronology may allow for outgassing preceding volcanism as a major source of CO2. We thus document a promising new way to obtain highly resolved, accurate, and precise numerical age models for legacy deep-sea sediment cores that does not depend on correlation to other records.

Influence of drilling technology on wear evolution of impregnated diamond bits

Diamond exposed on the surface of an impregnated diamond bit (IDB) is the key to breaking rock. The exposure conditions of the diamond affect the drilling efficiency and life of the bit. However, scant attention has been directed towards investigating the diamond exposure mechanism of IDBs, particularly under varying drilling process conditions. In this study, drilling experiments were conducted on granite under rotary and rotary-percussive drilling conditions using a self-developed drilling test platform. The evolution of diamond emergence on the surface of the IDB under two drilling technology conditions was evaluated; the typical characteristics of diamond wear and their causes were discussed. The results indicate that under rotary drilling conditions, the primary evolution process of diamond on a slippery IDB surface follows the sequence of Emerging→Whole→Blunt (Flat). The exposed diamond tends to be predominantly blunt and fractured, and a slippery IDB cannot be resharpened by increasing the weight-on-bit. The evolution process of a diamond under rotary-percussive drilling conditions encompasses Emerging→Whole→Fractured→Pull out, and the diamond on the surface of the bit is primarily fractured. Diamond emerges from the matrix in the form of points, lines, and planes, with different emergence states affecting its wear and failure modes. The main form of wear in diamonds is mechanical wear, which is dominated by abrasive and fatigue wear. The proportion of fractured diamonds was notably higher under rotary-percussive conditions than in rotary drilling conditions. The tail of the diamond under rotary-percussive drilling conditions was shorter than that under rotary drilling conditions. The impact effect in rotary-percussive drilling enhances the bit-rock contact, facilitating matrix wear and diamond emergence. These results provide valuable insight for optimizing the IDB design and refining drilling technology.

Investigation of continuous wave/coaxial waterjet-assisted laser combined machining of micro holes in GH3536

A two-step combined processing technique, combining a continuous-wave laser with a waterjet-assisted nanosecond laser, has been introduced to enhance the quality and efficiency of laser micro-hole processing for nickel-based superalloys. Initially, a through-hole was created using a continuous-wave laser, followed by hole refinement with a coaxial waterjet-assisted nanosecond laser. In the first step, orthogonal testing methods were employed to investigate the impact of various parameters, including power, duty ratio, frequency, defocusing amount, and processing time, on the entrance and exit apertures, as well as the hole taper. Through the analysis of variance (ANOVA) method, the optimal parameter combination A2B1C4D3E1 was identified, achieving the minimal hole taper. This combination comprised a power level of 80 %, a duty ratio of 15 %, a frequency of 400 Hz, a defocusing amount of 2 mm, and a processing time of 10 ms. In the second step, a comparison was made between scanning and trepan drilling machining methods. The results unequivocally demonstrated that scanning drilling achieves superior entrance and exit morphologies. Furthermore, the effect of water jet velocity on the morphology of micropores was thoroughly analyzed. The voltage range of the water pump was adjusted from 10 V to 24 V, revealing that a voltage of 20 V produced the smallest hole taper. The scanning filling diameter was accurately preset according to the preformed hole aperture as well as the thickness of the recast layer. Finally, after coaxial waterjet-assisted laser precision machining, the inner wall of the hole is free of cracks, and the recast layer and oxide layer are effectively minimized. The initial hole prefabrication with the continuous-wave laser took merely 0.01 s, and the subsequent fine-tuning with the coaxial waterjet-assisted laser took 2 min and 25 s.

Parameter optimization based on deepwater drilling system simulation: A pre-salt exploration well in Brazil

The vibration of downhole drilling tools is the primary factor that limits the ROP of deep-water salt drilling. Pre-drilling modeling is an essential method for analyzing the dynamic characteristics of the drilling system. Currently, there is limited research on coupling models between the single riser model and drill string model in deepwater drilling dynamics, which hampers offshore drilling dynamics development. In this study, we integrated the dynamic riser model with the flexible drillstring dynamic model, optimized the system's boundary conditions through experiments, and established an advanced full-scale deepwater drilling system. Through virtual drilling simulation analysis and energy flow calculations of the drilling process, we investigated the movement trajectory of the drillstring system at different positions and its correlation with downhole vibration in deepwater drilling. Finally, we performed parameter optimization on Brazil exploration well salt formation. The results indicate that the rotational speed significantly influences the vibration intensity and motion state of both the drill string and downhole drilling tool. Moreover, the kinetic energy and strain energy of BHA effectively reflect the motion state of the downhole drilling tool. When drilling salt and salt intercalation in the Brazil exploration well, the WOB was controlled within 200 kN and 180 kN, and the rotational speed was controlled within 180 rpm and 140 rpm, respectively. This ensured optimal stability and minimized vibrations within the drill string system. The virtual simulation work based on deepwater drilling systems can provide guidance for designing and planning actual drilling operations, as well as proposing reasonable drilling parameters to enhance stability and ROP in the drilling process.

Research on optimizing the drilling rate for through-tubing drilling and sand pumping tools

The efficient, cost-effective removal of sand in low-pressure and prone-to-leakage oil and gas wells poses a significant challenge that is currently being researched. The limited size of the newly developed through-tubing drilling and sand pumping tool leads to sand plugging when the drilling rate is too fast and low sand cleaning efficiency when the drilling rate is too slow. To address this issue, this paper utilizes FLUENT to simulate the migration behavior of sand-laden fluid within the drilling and sand extraction tool. The DDPM discrete phase model is employed to examine the trajectory and motion of sand particles within the fluid. Through theoretical calculations, it is determined that when the average particle size of the sand solution is 0.05 mm and the inner diameter of the tubing is 50.3 mm, the drilling rate should be kept below 687 mm/min to prevent sand plugging. The validity of the theoretical analysis is confirmed through the construction of a testing platform. This study offers practical guidance for the implementation of the new through-tubing drilling and sand pumping tool in engineering applications. To provide a new solution for addressing the problem of low pressure and easily leaking oil and gas wells.

Key Technologies for One-Time Installation of Super-Long Pipe Sheds in Tunnel Support Construction: A Case Study on Songhuai Youyuan Station (Line 9) in Zhengzhou Metro

In recent years, the pipe shed advanced support method has emerged as a new technique for excavating tunnels in weak surrounding rock. However, the necessity to maintain a certain inclination angle when constructing large pipe sheds unavoidably increases the excavation and lining quantities. Consequently, as the length of the pipe shed increases, construction errors also grow, resulting in larger excavations and backfilling works, thereby making it difficult to control the quality of pipe shed installations and limiting the development of the pipe shed method. Faced with the challenges presented by tunnel support construction as part of subway tunnel construction, this paper is based on the Songhuai Youyuan Station tunnel project involving Zhengzhou Metro Line 9. Field experiments were conducted, using high-torque horizontal drilling machines and pipe shed guiding technology to successfully complete the installation of a 208 m long pipe shed in a single operation (the longest in the world). Through case analysis and technological innovation, a feasible and effective drilling technology scheme was proposed. Compared with traditional methods, the key technology for installing super-long pipe sheds in a single operation reduced the construction time by 35% and construction costs by 25%, providing valuable insights for similar projects.

Numerical validation of a novel cuttings bed impeller for extended reach horizontal wells

To reduce the risk of downhole accidents resulting from poor wellbore cleaning during the drilling of extended reach horizontal wells, a new cuttings bed impeller is developed. The performance of existing cuttings bed impellers on wellbore cleaning efficiency is analyzed by multiphase numerical simulation. Based on this analysis, a new type of cuttings bed impeller is proposed, and its key structure parameters are optimized. Its cuttings removal performance under different working conditions is verified. The results show that the spiral impellers have the highest annular velocity, promoting the movement of the cuttings bed. Increasing the rotation speed of the impeller causes the cuttings bed to move further from the low side of the wellbore, facilitating the cuttings removal. Two major improvements are introduced to the new cuttings bed impeller: a positive displacement motor that enables the self-rotation of the impeller, and the elastic contacts on the spiral blades that stir cuttings bed and reduce friction with the wellbore. The optimized parameters of the new impeller are: helix angle of 60°, 4 blades, elastic contacts arranged in crossed pattern, and self-rotation speed of 60 r/min. It is also demonstrated that the new impeller achieves satisfactory cleaning results in both rotary drilling (84.71%) and sliding drilling (71.07%) conditions. This work provides a new solution for the efficient removal of cuttings in extended reach horizontal wells.

Drilling Process Monitoring for Predicting Mechanical Properties of Jointed Rock Mass: A Review

Reliably assessing the quality and mechanical properties of rock masses is crucial in underground engineering. However, existing methods have significant limitations in terms of applicability and accuracy. Therefore, a field measurement method that meets the real-time monitoring and safety requirements for the quality of engineering rock masses is needed. Firstly, the research findings of domestic and international scholars on the application of drilling process monitoring technology are comprehensively analyzed. Rotary cutting penetration tests are conducted on tuff rock masses containing fractures and joints. Various rock mass classification and evaluation standards are integrated with rotary penetration tests. Rotary cutting penetration tests are used to determine the residual strength of rock, based on this review. The rationality of the calculated mi parameter values is validated. The peak strength, residual strength, and errors of the rock are obtained based on the penetration method. The rock quality index rock quality designation from drilling (RQDd) is redefined, based on the drilling process monitoring apparatus (DPMA). Rock mass classification is conducted, based on the correlation between the standard deviation of rotary drilling energy and the rock quality designation (RQD). Additionally, a new relational formula is introduced to determine the RQD from variations in drilling energy, based on discontinuity frequency. This field measurement method undoubtedly provides a crucial scientific basis for rock design and construction, ensuring long-term safety in engineering applications.

Model establishment and flow field simulation analysis of high torque screw motor in ultra-deep well

Abstract To explore the distribution law of the flow field in the inner annular flow channel of the stator-rotor of the high-torque screw drill tool and determine the key performance parameters of the tool under different drilling fluid densities and flow rates, a physical model for fluid simulation was established with the 7/8 head screw motor as the research object to study the distribution law of the flow field and the output torque of the rotor at different flow rates and densities, and a comparative analysis was made with the actual test. The results show that the pressure of the internal flow channel is mainly concentrated at the entrance of the flow channel and the wall of the flow channel. The flow rate in the thick fluid domain is high, the flow rate in the thin fluid domain is low, and the flow rate in the thinnest area is about zero. The relationship between displacement pressure drop and output torque presents a positive correlation. When displacement increases, the output torque of the screw increases, and the relationship between displacement and torque presents a linear increase. The torque and displacement of fluid simulation under ideal conditions are larger than the actual test parameters. In the actual test, the drilling fluid temperature and experimental equipment factors affect the performance of the screw motor. In the process of fluid simulation, the setting of boundary conditions should refer to the real situation as much as possible to improve the accuracy of simulation results. The difference between fluid simulation and actual test parameter values is small and the trend is the same, so fluid simulation can guide practical application and reduce cost to a certain extent.

Experimental investigation and theoretical modeling of cutting mechanics using serrated tines in drilling lunar regolith simulant

Drilling is a widely used method for exploring extra-terrestrial bodies and seeking information on astrobiology, material composition, and evolution of the universe. The bit cutter of the drill tool is the main component that is in intense contact with the regolith and is of great importance for guaranteeing the cutting performance during drilling. The tine is a special type of cutter, and currently, there is no theoretical model describing its interaction with a lunar regolith simulant during cutting. To address this gap, semi-tine and full-tine cutting tests were performed at different cutting speeds, cutting depths, regolith densities, and tip angles. The experimental results showed that the regolith failure zone has an elliptical shape in the top view and a logarithmic spiral shape in the side view. Based on the failure pattern, a tine cutting mechanics model was built, and its results were compared with those of the experiments. The model exhibited good prediction accuracy for the cutting force, with a maximum error not exceeding 30.96% and an average error of 13.81%. To apply the model to extra-terrestrial drilling, a conical drill bit with multi-row serrated tines was designed. By analyzing the error between the theoretical and experimental values of the rotational torque, the model was further refined to provide a better match with the actual cutting results. The proposed cutting mechanics model describing the tine-regolith interaction mechanism can provide a reference for predicting drilling loads during planetary exploration.

Devising measures to reduce multi-frequency noise load on employees in machining area

The object of this study is the process of determining and managing the risks of noise exposure (NE) for employees at the mechanical department when machining metals on a drilling machine (DM). The problem relates to the increase in the risk of an employee receiving an industrial injury because of NE at the workplace of a machine tool. The impact of noise on the human body depends on the duration of exposure, the level of sound pressure, and its intensity. An important characteristic of noise is its frequency composition, as it can affect the perception of sounds and the human body. Prolonged exposure to noise can damage various systems in the human body or cause pain. Therefore, it is important to understand the impact of NE on workers and devise measures to reduce the negative impact on their health and work productivity. The research is based on real-time noise measurements followed by their decomposition into octave frequencies and modeling of noise propagation in the room with and without the use of various types and designs of soundproof barriers (SB). In the course of the study of NE propagation during drilling on the machine, an excess of noise levels at medium and high frequencies near the noise source was found. An employee who works on DM is exposed to high-frequency noise that exceeds the established normative indicators. Therefore, it is necessary to use personal protective equipment for the machine operator and install safety equipment to protect other workplaces. The use of the latter makes it possible to significantly reduce the impact of NE on workers, in particular, at low frequencies by 20.8 %, at medium frequencies by 15.6 %, and at high frequencies by 17.3 %

Unsupervised learning-enabled pulsed infrared thermographic microscopy of subsurface defects in stainless steel

Metallic structures produced with laser powder bed fusion (LPBF) additive manufacturing method (AM) frequently contain microscopic porosity defects, with typical approximate size distribution from one to 100 microns. Presence of such defects could lead to premature failure of the structure. In principle, structural integrity assessment of LPBF metals can be accomplished with nondestructive evaluation (NDE). Pulsed infrared thermography (PIT) is a non-contact, one-sided NDE method that allows for imaging of internal defects in arbitrary size and shape metallic structures using heat transfer. PIT imaging is performed using compact instrumentation consisting of a flash lamp for deposition of a heat pulse, and a fast frame infrared (IR) camera for measuring surface temperature transients. However, limitations of imaging resolution with PIT include blurring due to heat diffusion, sensitivity limit of the IR camera. We demonstrate enhancement of PIT imaging capability with unsupervised learning (UL), which enables PIT microscopy of subsurface defects in high strength corrosion resistant stainless steel 316 alloy. PIT images were processed with UL spatial–temporal separation-based clustering segmentation (STSCS) algorithm, refined by morphology image processing methods to enhance visibility of defects. The STSCS algorithm starts with wavelet decomposition to spatially de-noise thermograms, followed by UL principal component analysis (PCA), fine-tuning optimization, and neural learning-based independent component analysis (ICA) algorithms to temporally compress de-noised thermograms. The compressed thermograms were further processed with UL-based graph thresholding K-means clustering algorithm for defects segmentation. The STSCS algorithm also includes online learning feature for efficient re-training of the model with new data. For this study, metallic specimens with calibrated microscopic flat bottom hole defects, with diameters in the range from 203 to 76 µm, were produced using electro discharge machining (EDM) drilling. While the raw thermograms do not show any material defects, using STSCS algorithm to process PIT images reveals defects as small as 101 µm in diameter. To the best of our knowledge, this is the smallest reported size of a sub-surface defect in a metal imaged with PIT, which demonstrates the PIT capability of detecting defects in the size range relevant to quality control requirements of LPBF-printed high-strength metals.

Prediction of Drilling Efficiency for Rotary Drilling Rig Based on an Improved Back Propagation Neural Network Algorithm

Accurately predicting the drilling efficiency of rotary drilling is the key to achieving intelligent construction. The current types of principle analysis (based on traditional interactive experimental methods) and efficiency prediction (based on simulation models) cannot meet the requirements needed for the efficient, real-time, and accurate drilling efficiency predictions of rotary drilling rigs. Therefore, we adopted a method based on machine learning to predict drilling efficiency. The extremely complex rock fragmentation process in drilling conditions also brings challenges to predicting drilling efficiency. Therefore, this article went through a combination of mechanism and data analysis to conduct correlation analysis and to clarify the drilling characteristic parameters that are highly correlated with drilling efficiency, and it then used them as inputs for machine learning models. We propose a rotary drilling rig drilling efficiency prediction model based on the GA-BP neural network to construct an accurate and efficient drilling efficiency prediction model. Compared with traditional BP neural networks, it utilizes the global optimization ability of a genetic algorithm to obtain the initial weights and thresholds of a BP neural network in order to avoid the defect of ordinary BP neural networks, i.e., that they easily fall into local optimal solutions during the training process. The average prediction accuracy of the GA-BP neural network is 93.6%, which is 3.1% higher than the traditional BP neural network.

Enhancing Pencak Silat Education through Application-Based Learning Media: A Comparative Study on Teaching Effectiveness and Student Outcomes

This examination is advancement research that expects to configuration learning media that contains appraisals in hand to hand fighting contests, particularly combative techniques and particularly aiding the field of sports science, particularly in the field of refereeing and sports accomplishments in North Sumatra. An application that contains assessments in both legal and illegal pencak silat competitions is the form of the developed media. These assessments are presented in the form of videos and match scoring. Additionally, the application includes a useful assessment of fundamental martial arts and martial arts techniques for use in classes. This thought emerged when specialists wanted to expect to discover that was more viable and proficient, as well as valuable for selecting contender for combative techniques and hand to hand fighting officials. The distribution of training materials for martial arts referees can also benefit from this application, particularly in the field of refereeing. The information displayed in this study is a correlation of the viability of the learning model for every mark of the evaluation of the new learning model (in the wake of utilizing the application) more successful than the old learning model (prior to utilizing the application). The new learning model has an efficiency of 85.71 percent, while the old learning model has an efficiency of 60 percent. The old learning model's average effectiveness of implementation indicators was 50%, while the new model's average effectiveness was 70%. Therefore, it can be concluded that the new learning model is superior to the old learning model (previous to using a drill machine) after using a drill machine.

Adaptive fixed-time fault-tolerant tracking control for rotary steerable drilling tool systems

In this paper, the problem of adaptive fixed-time fault-tolerant tracking control is investigated for rotary steerable drilling tool systems (RSDTSs). Markov jump system (MJS) is used to describe the RSDTS with varying parameters which are induced by the changing environment. By employing the smooth projection operator technique, adaptive laws are established to estimate the faults. Based on the fault compensation strategy, a new adaptive fixed-time fault-tolerant tracking control scheme is proposed to ensure that the RSDTS is globally stochastically practically fixed-time stable. In addition, to reduce the computational burden in the backstepping framework, the derivatives of the virtual control are directly derived using command filters. Finally, the experiment performed on the rotary steerable drilling tool systems prototype is exploited to demonstrate the feasibility and effectiveness of the proposed method.

Standardized Testing for Thermal Evaluation of Bone Drilling: Towards Predictive Assessment of Thermal Trauma.

To ensure the prevention of thermal trauma and tissue necrosis during bone drilling in surgical procedures, it is crucial to maintain temperatures below the time- and temperature-dependent threshold of 50 °C for 30 s. However, the absence of a current standard for assessing temperatures attained during bone drilling poses a challenge when comparing findings across different studies. This article aims to address this issue by introducing a standardized testing method for acquiring thermal data during experimental bone drilling. The method requires the use of three controlled variables: infrared thermography, standard bone blocks, and a regulated drilling procedure involving a drill press with irrigation that simulates a surgeon. By utilizing this setup, we can obtain temperature data that can be effectively applied in the evaluation of other variables, such as surgical techniques or drill bit design, and translate the data into bone damage/clinical outcomes. Two surgical drill bits (2.0 mm-diameter twist drill bit and 3.3 mm-diameter multi-step drill bit) are compared using this experimental protocol. The results show the 2.0 mm bit reached significantly higher temperatures compared to the 3.3 mm bit when preparing an osteotomy (p < 0.05). The 2.0 mm drill bit reached temperatures over 100 °C while the 3.3 mm drill bit did not exceed 50 °C.