Thermomechanical damage in cortical bone caused by margins of surgical drill bit: A finite element analysis

BACKGROUND AND OBJECTIVE

Conventional surgical drill bits suffer from several drawbacks, including extreme heat generation, breakage, jam, and undesired breakthrough. Understanding the impacts of drill margin on bone damage can provide insights that lay the foundation for improvement in the existing surgical drill bit. However, research on drill margins in bone drilling is lacking. This work assesses the influences of margin height and width on thermomechanical damage in bone drilling.

METHODS

Thermomechanical damage-maximum bone temperature, osteonecrosis diameter, osteonecrosis depth, maximum thrust force, and torque-were calculated using the finite element method under various margin heights (0.05-0.25 mm) and widths (0.02-0.26 mm). The simulation results were validated with experimental tests and previous research data.

RESULTS

The effect of margin height in increasing the maximum bone temperature, osteonecrosis diameter, and depth were at least 19.1%, 41.9%, and 59.6%, respectively. The thrust force and torque are highly sensitive to margin height. A higher margin height (0.21-0.25 mm) reduced the thrust force by 54.0% but increased drilling torque by 142.2%. The bone temperature, osteonecrosis diameter, and depth were 16.5%, 56.5%, and 81.4% lower, respectively, with increasing margin width. The minimum thrust force (11.1 N) and torque (41.9 Nmm) were produced with the highest margin width (0.26 mm). The margin height of 0.05-0.13 mm and a margin width of 0.22-0.26 produced the highest sum of weightage.

CONCLUSIONS

A surgical drill bit with a margin height of 0.05-0.13 mm and a margin width of 0.22-0.26 mm can produce minimum thermomechanical damage in cortical bone drilling. The insights regarding the suitable ranges for margin height and width from this study could be adopted in future research devoted to optimizing the margin of the existing surgical drill bit.

Parametric study of bone drilling by the Kirschner wire

In order to improve the quality and reduce mechanical damage during bone drilling in surgeries, the three key parameters in drilling by the Kirschner wire are experimentally studied based on the response surface method (RSM). And through response surface analysis, a predictive model of each factor and response value is established. The experimental results found that when the beveled plane angle Φ = 10°, the rotational speed n = 1200 rpm, and the feed speed v_f = 20 mm/min. Not only the drilling force is minimized, the delamination coefficient and the height of the hole exit burr are also the minimum. Therefore, the smaller bevel angle, the feed speed and the higher rotation speed can effectively reduce the drilling force, the delamination factor and the height of the hole exit burr, and significantly improve the drilling quality.

Characterizing the trade-off between range of motion and stability of reverse total shoulder arthroplasty

BACKGROUND

The trade-off between range of motion (ROM) and stability of reverse total shoulder arthroplasty (RSA) has long been hypothesized to exist but has not yet been well characterized. The goal of this study was to use design optimization techniques to obtain a Pareto curve, which quantifies the trade-off between 2 competing objectives and is defined by the performance of optimum designs that maximize one surgical outcome without sacrificing the other.

METHODS

Multi-objective design optimization techniques were used; 4 design and surgical parameters including glenoid lateralization (GLat), neck-shaft angle (NSA), inferior offset of the center of rotation (COR_inf), and humerus lateralization (HLat) were tuned simultaneously. The ROM and stability, the objectives to be optimized, of any candidate design were characterized computationally using a combination of finite element models, musculoskeletal models, analytical equations, and surrogate models. Optimum designs and Pareto curves were determined separately for a standard cup depth and a shallow cup depth. The performance of the optimum designs, in terms of ROM and stability, was compared with a representative commercially available design.

RESULTS

A Pareto curve was obtained for each cup depth, confirming there is a trade-off between ROM and stability of RSA. In comparison to the commercially available design (cup depth, 8.1 mm; GLat, 5 mm; NSA, 155°; COR_inf, 0 mm; HLat, 0 mm), the designs optimized for ROM offered 38.8% (cup depth, 6 mm; GLat, 16 mm; NSA, 163.6°; COR_inf, 4 mm; HLat, 0.6 mm) and 35.2% (cup depth, 8.1 mm; GLat, 16 mm; NSA, 160.5°; COR_inf, 4 mm; HLat, -0.2 mm) improvement in ROM. The designs optimized for stability (cup depth of 6 mm with GLat of 16 mm, NSA of 170°, COR_inf of 4 mm, and HLat of 3 mm and cup depth of 8.1 mm with GLat of 16 mm, NSA of 170°, COR_inf of 4 mm, and HLat of 3 mm) both offered 12.4% improvement in stability over the commercially available design. Designs in the toe region of the Pareto curve offered between 75% and 90% of the maximum possible improvement over the commercially available design for both objectives.

CONCLUSION

It was confirmed that a trade-off exists between ROM and stability of RSA, in which maximizing one outcome requires a sacrifice in the other. The relative gains and sacrifices in the competing outcomes when traversing the Pareto front could aid in understanding clinically optimum designs based on patient-specific needs.

Power-Tool Use in Orthopaedic Surgery: Iatrogenic Injury, Its Detection, and Technological Advances: A Systematic Review

Power tools are an integral part of orthopaedic surgery but have the capacity to cause iatrogenic injury. With this systematic review, we aimed to investigate the prevalence of iatrogenic injury due to the use of power tools in orthopaedic surgery and to discuss the current methods that can be used to reduce injury.

Non-Fourier bioheat model for bone grinding with application to skull base neurosurgery

Bone grinding is used to remove the skull bone and access tumors through the nasal passage during cranial base neurosurgery. The generated heat of the spherical diamond tool propagates and could damage the nerves or coagulate the arteries blood. Little is known about the non-Fourier behavior of heat propagation during bone grinding. Therefore, this study develops an analytical model of the hyperbolic Pennes bioheat transfer equation (HPBTE) to calculate the three-dimensional temperature and necrosis in the grinding region. In vitro experimental investigations were carried out, and the contact zone temperature was measured using an infrared thermography system to validate the proposed thermal model. The results demonstrate that the HPBTE provides more reliable temperature evaluation and thermal damage than Fourier or parabolic heat transfer equation (PHTE). Due to the low thermal diffusivity of the bone, the lower grinding feed rate leads to higher temperature amplitude and a smaller radius of the affected zone in the surface and depth of the bone. Also, the intensity of bone necrosis decreases with the increase of the feed rate, and the shape of the damage zone becomes stretched. This analytical model can assess the potential risk of the surgery before clinical trials. Also, it could be used for comparing the different operating conditions to minimize bone necrosis and improve the control process in neurosurgeries.

Comparative statement for diametric delamination in drilling of cortical bone with conventional and ultrasonic assisted drilling techniques

Drilled hole quality is a significant parameter for successful orthopedic surgery. The present investigation is an effort to reduce the delamination produced drilling with state-of-the-art hybrid drilling i.e. ultrasonically-assisted drilling. A comparative analysis has carried out as per experimental design to assess the ultrasonic drilling with conventional drilling. The novelty of the work is the use of coordinate measuring machine (CMM) for characterization of the delamination during bone drilling. The results revealed that ultrasonically-assisted drilling caused lesser delamination than conventional drilling. The maximum percentage delamination during conventional drilling was found to be 9.153% and 8.541% during ultrasonically-assisted drilling.

Surface quality and pullout strength of ultrasonically-assisted drilling cortical bone

Bone surgery is a complex process involving sustainable and healthy human recuperation, but poor surface quality and loose implant fixtures can affect the recovery time of orthopedic patients. However, it has been demonstrated that the application of ultrasonic vibration during drilling procedures can improve the success of bone remediation procedures. The focus of the present paper was on the investigation of surface quality and pullout strength of drilled holes. After analyzing the special kinematic characteristics of the ultrasonically-assisted drilling (UAD), UAD testing using fresh cortical bone was carried out and compared with the results obtained after conventional drilling (CD) procedures. Surface roughness measurements and microscope examination were used to evaluate surface quality, and an electro-mechanical tensile machine was used to measure pullout resistance. The test findings indicated that surface roughness was reduced by 17-68.7% when using UAD; the axial pullout strength of screws inserted into UAD holes was significantly increased by 4.28-30.1% compared to that of CD. It was found also that low spindle speeds and high feed rates reduced surface quality and the stability of the inserted cortical screws. The findings demonstrated that UAD produced better surface quality and higher pullout strengths, which could provide greater stability for implants and improved post-operative recovery.

Surgical Drill Bit Design and Thermomechanical Damage in Bone Drilling: A Review

As drilling generates substantial bone thermomechanical damage due to inappropriate cutting tool selection, researchers have proposed various approaches to mitigate this problem. Among these, improving the drill bit design is one of the most feasible and economical solutions. The theory and applications in drill design have been progressing, and research has been published in various fields. However, pieces of information on drill design are dispersed, and no comprehensive review paper focusing on this topic. Systemizing this information is crucial and, therefore, the impetus of this review. Here, we review not only the state-of-the-art in drill bit designs-advances in surgical drill bit design-but also the influences of each drill bit geometries on bone damage. Also, this work provides future directions for this topic and guidelines for designing an improved surgical drill bit. The information in this paper would be useful as a one-stop document for clinicians, engineers, and researchers who require information related to the tool design in bone drilling surgery.

INVESTIGATION OF BONE DRILLING FOR SECURE IMPLANT FIXATION IN HUMAN FEMURS: TAGUCHI OPTIMIZATION AND PREDICTIVE FORCE MODELS WITH EXPERIMENTAL VALIDATION

Drilling procedures are important to optimize and ensure the strongest fixation in bone fracture treatment and reconstruction surgery. The mechanistic force models currently available for bovine bones, human spines and human mandibles are not relevant to perform drilling through human femurs. The present study addresses this lack of information and aims to develop the predictive force models for drilling human femurs at different regions and directions. In this study, 10 freshly harvested cadaveric human femurs were included, and a surgical drill bit of 3.2[Formula: see text]mm diameter was used to make 4[Formula: see text]mm deep holes. Different spindle speeds (500, 1000 and 1500[Formula: see text]rpm), feed rates (40, 60 and 80[Formula: see text]mm/min), and apparent density between 0.98 and 1.98[Formula: see text]g/cm3were considered. The optimal parameters [Formula: see text], [Formula: see text], and [Formula: see text] respectively obtained for longitudinal, radial, and circumferential direction could minimize the thrust forces in bone drilling by up to 7.70, 10.50, and 16.20 N, respectively. Validation study demonstrated that the force model developed could predict the thrust force from computed tomography data sets of the patient, only with 5.05%, 6.74%, and 4.91% as a maximum error in longitudinal, radial, and circumferential direction. This important tool can assist to perform complicated surgical operations.

Parametric effect of vibrational drilling on osteonecrosis and comparative histopathology study with conventional drilling of cortical bone

Drilling to the bones is required to re-fix them at their appropriate location using the implants. During drilling some thermal and mechanical losses may be faced by the bone and surrounding tissues which may lead to the serious issue in terms of osteonecrosis. Osteonecrosis is one of the reasons for impaired healing process for the fractured bone and causes further complications like low pullout strength of cortical screws and bone crush. In order to maintain the low temperature during bone drilling, this study focused the thermal damages observed by the bone and its surrounding during bone drilling and compared the results of conventional and vibrational drilling techniques. Parametric optimization under the influence of vibrations was also studied. Drilling has been done with the both drilling technique, and results were recorded in terms of temperature raise. Optimal solution for drilling the bone has been accessed using Taguchi optimization technique. The morphological comparison has been done for conventional and vibrational drilled holes using histopathology of drilled bones sections. From Taguchi optimization, it was observed that R1F1A1 is the parametric combination which gives minimum thermal injury to the bone in case of vibrational bone drilling. Analysis of variance cleared that the all parameters involved significantly affect the results (P ≤ 0.05). Rotational speed was found to be the most influential factor among the all with 80.53%. Histopathology studies of bone specimens help to understand how heat generation affects the bone morphology during drilling. The specimens drilled with vibrational drilling show less damage in terms of osteonecrosis near the drill site which shows the significance of vibrational drilling in case of orthopedic surgeries. The raise in temperature during drilling is collective result of different drilling parameters. Vibrational drilling was observed a helping tool to control the thermal damage in bone drilling.

Parameters affecting mechanical and thermal responses in bone drilling: A review

Surgical bone drilling is performed variously to correct bone fractures, install prosthetics, or for therapeutic treatment. The primary concern in bone drilling is to extract donor bone sections and create receiving holes without damaging the bone tissue either mechanically or thermally. We review current results from experimental and theoretical studies to investigate the parameters related to such effects. This leads to a comprehensive understanding of the mechanical and thermal aspects of bone drilling to reduce their unwanted complications. This review examines the important bone-drilling parameters of bone structure, drill-bit geometry, operating conditions, and material evacuation, and considers the current techniques used in bone drilling. We then analyze the associated mechanical and thermal effects and their contributions to bone-drilling performance. In this review, we identify a favorable range for each parameter to reduce unwanted complications due to mechanical or thermal effects.