scholarly journals Ultrasonic-Assisted Drilling of Cortical and Cancellous Bone in a Comparative Point of View

2021 ◽  
Author(s):  
Sousan Pourgiv ◽  
Nima Jamshidi ◽  
Aminollah Mohammadi ◽  
Alireza Mosavar
Keyword(s):  
Bone Tissue ◽  
Cancellous Bone ◽  
Healing Process ◽  
Drilling Process ◽  
Drilling Force ◽  
Excessive Heat ◽  
Micro Cracks ◽  
Ultrasonic Assisted ◽  
Conventional Drilling

Abstract Background: A potential method in drilling of bone is ultrasonic-assisted drilling. In addition, during the drilling of bone, which is common in clinical surgeries, excessive heat generation and drilling force may lead to damages in bone tissue, and thus to failure of implants and fixation screws or delay in healing process. The aim of this study was to appraise efficiency of ultrasonic-assisted drilling in comparison to conventional drilling.Methods: In addition to investigating drilling force and temperature elevation, their effects on arising osteonecrosis and micro-cracks were explored in ultrasonic-assisted and conventional drilling through histopathologic assessment and microscopic imaging. In this regard, three drilling speeds and two drilling feed-rates were considered as drilling variables in the in-vitro experiments. Moreover, numerical modeling gave an insight into temperature distribution during drilling process in the both methods and compared three different vibration amplitudes. Results: Although temperature elevations were lower in the conventional drilling, the ultrasonic-assisted drilling had lesser drilling forces. Furthermore, the latter method had smaller osteonecrosis regions, and did not have micro-cracks in cortical bone and destructions in structure of cancellous bone.Conclusions: The ultrasonic-assisted drilling, which caused lesser damages to the bone tissue in both cortical and cancellous bone, was more comparatively advantageous.

scholarly journals Comparative Analysis of Cutting Forces, Torques, and Vibration in Drilling of Bovine, Porcine, and Artificial Femur Bone with Considerations for Robot Effector Stiffness

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Oluseyi Adewale Orelaja ◽  
Xingsong Wang ◽  
Donghua Shen ◽  
Dauda Sh. Ibrahim ◽  
Tianzheng Zhao ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Cutting Forces ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Drilling Process ◽  
Robot Arm ◽  
Drilling Force ◽  
Significant Drop ◽  
Negative Effect ◽  
Conventional Drilling

Bone drilling is known as one of the most sensitive milling processes in biomedical engineering field. Fracture behavior of this cortical bone during drilling has attracted the attention of many researchers; however, there are still impending concerns such as necrosis, tool breakage, and microcracks due to high cutting forces, torques, and high vibration while drilling. This paper presents a comparative analysis of the cutting forces, torques, and vibration resulted on different bone samples (bovine, porcine, and artificial femur) using a 6dof Robot arm effector with considerations of its stiffness effects. Experiments were conducted on two spindle speeds of 1000 and 1500 rpm with a drill bit diameter of 2.5 mm and 6 mm depth of cut. The results obtained from the specimens were processed and analyzed using MATLAB R2015b and Visio 2000 software; these results were then compared with a prior test using manual and conventional drilling methods. The results obtained show that there is a significant drop in the average values of maximum drilling force for all the bone specimens when the spindle speed changes from 1000 rev/min to 1500 rev/min, with a drop from (20.07 to 12.34 N), approximately 23.85% for bovine, (11.25 to 8.14 N) with 16.03% for porcine, and (5.62 to 3.86 N) with 33.99% for artificial femur. The maximum average values of torque also decrease from 41.2 to 24.2 N·mm (bovine), 37.0 to 21.6 N·mm (porcine), and 13.6 to 6.7 N·mm (artificial femur), respectively. At an increase in the spindle speed, the vibration amplitude on all the bone samples also increases considerably. The variation in drilling force, torque, and vibration in our result also confirm that the stiffness of the robot effector joint has negative effect on the bone precision during drilling process.

An in-vitro study of cutting force and torque during rotary ultrasonic bone drilling

2016 ◽  
Vol 232 (9) ◽  
pp. 1549-1560 ◽  
Author(s):  
Vishal Gupta ◽  
Pulak Mohan Pandey
Keyword(s):  
In Vitro Study ◽  
Vibrational Amplitude ◽  
Drilling Process ◽  
Bone Drilling ◽  
Surgical Operation ◽  
Confidential Interval ◽  
Drill Diameter ◽  
Ultrasonic Assisted ◽  
Process Factors

Bone drilling is one of the steps in a typical surgical operation that is performed around the world for reconstruction and repair of the fractured bone. During the last decade, various techniques, such as two-step drilling, ultrasonic-assisted bone drilling and laser drilling, have been introduced to control the level of forces and torque during bone drilling. In this research, rotary ultrasonic bone drilling has been successfully attempted to minimize the forces and torque during bone drilling. The drilling experiments were planned and carried out on pig bones using the design of experiments (response surface methodology). Analysis of variance was carried out to find the effect of process factors such as rotational speed, feed rate, drill diameter and ultrasonic vibrational amplitude on the force and torque. Statistical models were developed for the force and torque with 95% confidential interval, and confirmation experiments have been carried out to validate the models. Microcracks developed during drilling process were characterized by scanning electron microscopy. The results revealed that rotary ultrasonic bone drilling process offered a lower force and torque making it a potential process for bone drilling in orthopedic surgery.

scholarly journals Processing of Polyester-Urethane Filament and Characterization of FFF 3D Printed Elastic Porous Structures with Potential in Cancellous Bone Tissue Engineering

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4457
Author(s):  
Agnieszka Haryńska ◽  
Iga Carayon ◽  
Paulina Kosmela ◽  
Anna Brillowska-Dąbrowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
3D Printing ◽  
Bone Tissue ◽  
Cancellous Bone ◽  
Thermoplastic Polyurethane ◽  
Porous Structures ◽  
Fused Filament Fabrication ◽  
Polyester Urethane ◽  
Tissue Structures

This paper addresses the potential of self-made polyester-urethane filament as a candidate for Fused Filament Fabrication (FFF)-based 3D printing (3DP) in medical applications. Since the industry does not provide many ready-made solutions of medical-grade polyurethane filaments, we undertook research aimed at presenting the process of thermoplastic polyurethane (TPU) filament formation, detailed characteristics, and 3DP of specially designed elastic porous structures as candidates in cancellous tissue engineering. Additionally, we examined whether 3D printing affects the structure and thermal stability of the filament. According to the obtained results, the processing parameters leading to the formation of high-quality TPU filament (TPU_F) were captured. The results showed that TPU_F remains stable under the FFF 3DP conditions. The series of in vitro studies involving long- and short-term degradation (0.1 M phosphate-buffered saline (PBS); 5 M sodium hydroxide (NaOH)), cytotoxicity (ISO 10993:5) and bioactivity (simulated body fluid (SBF) incubation), showed that TPU printouts possessing degradability of long-term degradable tissue constructs, are biocompatible and susceptible to mineralization in terms of hydroxyapatite (HAp) formation during SBF exposure. The formation of HAp on the surface of the specially designed porous tissue structures (PTS) was confirmed by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) studies. The compression test of PTS showed that the samples were strengthened due to SBF exposure and deposited HAp on their surface. Moreover, the determined values of the tensile strength (~30 MPa), Young’s modulus (~0.2 GPa), and compression strength (~1.1 MPa) allowed pre-consideration of TPU_F for FFF 3DP of cancellous bone tissue structures.

Finite Element Simulations of Thermal Affected Zone during Bone Drilling

2013 ◽  
Vol 421 ◽  
pp. 76-80 ◽  
Author(s):  
Li Wen Chen ◽  
Kai Szu Luo ◽  
Jik Chang Leong ◽  
Jun Yan Zhuang ◽  
Nan Ming Yeh ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cancellous Bone ◽  
Element Model ◽  
Maximum Diameter ◽  
Drilling Process ◽  
Stress Distributions ◽  
Bone Drilling ◽  
Drilling Force ◽  
Thermal Affected Zone

In this study, an elastic-plastic finite element model is used to simulate the thermal affected bone (TAZ) during bone drilling process under the condition of constant applied drilling force. Various drilling times and measurement depths are investigated to explore the size of TAZ and stress distributions within the bone. The results indicate that the maximum TAZ occurs at the interface of cortical bone and cancellous bone. The maximum diameter of TAZ is found to be 3.5 mm in this study.

Comparison of Thrust Force in Ultrasonic Assisted Drilling and Conventional Drilling of Aluminum Alloy

2016 ◽  
Vol 861 ◽  
pp. 38-43 ◽  
Author(s):  
Xiao Feng Li ◽  
Zhi Gang Dong ◽  
Ren Ke Kang ◽  
Yi Dan Wang ◽  
Jin Ting Liu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Vibration Amplitude ◽  
Complex Shape ◽  
Thrust Force ◽  
Drill Bit ◽  
Twist Drill ◽  
Drilling Force ◽  
Drilling Parameters ◽  
Ultrasonic Assisted ◽  
Conventional Drilling

The origin of drilling force in drilling with twist drill is quite complicated owning to the complex shape of the drill bit cutting edges. In this paper, the drilling experiments both with and without the ultrasonic were designed and conducted on aluminum alloy with pre-drilled hole. The drilling force was tested and the different effects between the cutting edges of the twist drill on the drilling force were analyzed under various drilling parameters including the spindle speed, feed rate and vibration amplitude. The drilling force of conventional drilling (CD) and ultrasonic assisted drilling (UAD) was characterized and the roles of the ultrasonic vibration in drilling were discussed.

In vitro comparison of cortical bone temperature generation between traditional sequential drilling and a newly designed step drill in the equine third metacarpal bone

2009 ◽  
Vol 22 (06) ◽  
pp. 442-447 ◽  
Author(s):  
J. García-López ◽  
L. S. Maranda ◽  
K. A. Bubeck
Keyword(s):  
Heat Generation ◽  
Metacarpal Bone ◽  
Maximum Temperature ◽  
Drilling Force ◽  
Maximum Heat ◽  
Pilot Hole ◽  
Excessive Heat ◽  
Metacarpal Bones ◽  
Step Drill

Summary Objectives: To compare heat generation and time to finish between a new step drill and sequential drilling in order to create a 6.2 mm pilot hole for insertion of a positive profile transfixation pin into the equine third metacarpal bone. Methods: Nine pairs of equine third metacarpal bones from cadavers of adult horses were used. Maximum temperature rise of the bone was measured continuously at the cis- and trans-cortices 1, 2 and 3 mm from the final pilot hole during creation of a 6.2 mm hole using a step drill and sequential drilling with 4.5, 5.5 and 6.2 mm drill bits. Five holes were drilled into the mid diaphysis of each bone in lateral to medial direction, and drilling forces of 60, 80 and 120 N were used (15 holes in each group). Time from start to finish was measured and cortical thickness was recorded for each hole. Results: The maximum heat generation (mean [95% CI]) with step drilling and sequential drilling was not significantly different at 60 N and 120 N of drilling force. However, at 80 N of drilling force, the 2.13 ºC difference between the two drilling techniques was significant. The time to finish (seconds) was significantly shorter for the holes created by step drilling (35.1 [32.06 – 37.59]) than by sequential drilling (145.8 [138.52 – 151.67]) (P < 0.001). Clinical Relevance: Based on our results, we concluded that the step drill is a viable alternative to traditional sequential drilling of equine third metacarpal bone because it did not result in excessive heat generation that can result in bone necrosis.

Hydrogels: A Versatile Drug Delivery Carrier Systems

1970 ◽  
Vol 5 (3) ◽  
pp. 1745-1756
Author(s):  
L H Baldaniya ◽  
Sarkhejiya N A
Keyword(s):  
Drug Delivery ◽  
Protein Delivery ◽  
Structural Integrity ◽  
Healing Process ◽  
Polymer Chains ◽  
Wound Healing Process ◽  
Aqueous Environment ◽  
Preparation Methods ◽  
Control Drug

Hydrogels are the material of choice for many applications in regenerative medicine due to their unique properties including biocompatibility, flexible methods of synthesis, range of constituents, and desirable physical characteristics. Hydrogel (also called Aquagel) is a network of polymer chains that are hydrophilic, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are highly absorbent (contain ~99.9% water), natural or synthetic polymers. Hydrogel also possess a degree of flexibility very similar to natural tissue, due to its significant water content. It can serve as scaffolds that provide structural integrity to tissue constructs, control drug and protein delivery to tissues and cultures. Also serve as adhesives or barriers between tissue and material surfaces. The positive effect of hydrogels on wounds and enhanced wound healing process has been proven. Hydrogels provide a warm, moist environment for wound that makes it heal faster in addition to its useful mucoadhesive properties. Moreover, hydrogels can be used as carriers for liposomes containing variety of drugs, such as antimicrobial drugs. Hydrogels are water swollen polymer matrices, with a tendency to imbibe water when placed in aqueous environment. This ability to swell, under biological conditions, makes it an ideal material for use in drug delivery and immobilization of proteins, peptides, and other biological compounds. Hydrogels have been extensively investigated for use as constructs to engineer tissues in vitro. This review describes the properties, classification, preparation methods, applications, various monomer used in formulation and development of hydrogel products.

scholarly journals Enterococcus faecalis exploits the human fibrinolytic system to drive excess collagenolysis: implications in gut healing and identification of druggable targets

2020 ◽  
Vol 318 (1) ◽  
pp. G1-G9 ◽  
Author(s):  
Richard A. Jacobson ◽  
Kiedo Wienholts ◽  
Ashley J. Williamson ◽  
Sara Gaines ◽  
Sanjiv Hyoju ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Healing Process ◽  
Abdominal Sepsis ◽  
Infectious Complications ◽  
Fibrinolytic System ◽  
Clinical Safety ◽  
High Concentrations ◽  
Clinically Significant

Perforations, anastomotic leak, and subsequent intra-abdominal sepsis are among the most common and feared complications of invasive interventions in the colon and remaining intestinal tract. During physiological healing, tissue protease activity is finely orchestrated to maintain the strength and integrity of the submucosa collagen layer in the wound. We (Shogan, BD et al. Sci Trans Med 7: 286ra68, 2015.) have previously demonstrated in both mice and humans that the commensal microbe Enterococcus faecalis selectively colonizes wounded colonic tissues and disrupts the healing process by amplifying collagenolytic matrix-metalloprotease activity toward excessive degradation. Here, we demonstrate for the first time, to our knowledge, a novel collagenolytic virulence mechanism by which E. faecalis is able to bind and locally activate the human fibrinolytic protease plasminogen (PLG), a protein present in high concentrations in healing colonic tissue. E. faecalis-mediated PLG activation leads to supraphysiological collagen degradation; in this study, we demonstrate this concept both in vitro and in vivo. This pathoadaptive response can be mitigated with the PLG inhibitor tranexamic acid (TXA) in a fashion that prevents clinically significant complications in validated murine models of both E. faecalis- and Pseudomonas aeruginosa-mediated colonic perforation. TXA has a proven clinical safety record and is Food and Drug Administration approved for topical application in invasive procedures, albeit for the prevention of bleeding rather than infection. As such, the novel pharmacological effect described in this study may be translatable to clinical trials for the prevention of infectious complications in colonic healing. NEW & NOTEWORTHY This paper presents a novel mechanism for virulence in a commensal gut microbe that exploits the human fibrinolytic system and its principle protease, plasminogen. This mechanism is targetable by safe and effective nonantibiotic small molecules for the prevention of infectious complications in the healing gut.

scholarly journals Development of a Topical Insulin Polymeric Nanoformulation for Skin Burn Regeneration: An Experimental Approach

2021 ◽  
Vol 22 (8) ◽  
pp. 4087
Author(s):  
Maria Quitério ◽  
Sandra Simões ◽  
Andreia Ascenso ◽  
Manuela Carvalheiro ◽  
Ana Paula Leandro ◽  
...  
Keyword(s):  
Wound Healing ◽  
Healing Process ◽  
In Vitro Release ◽  
Peptide Hormone ◽  
Plga Nanoparticles ◽  
Wound Healing Process ◽  
Target Area ◽  
Encapsulation Process

Insulin is a peptide hormone with many physiological functions, besides its use in diabetes treatment. An important role of insulin is related to the wound healing process—however, insulin itself is too sensitive to the external environment requiring the protective of a nanocarrier. Polymer-based nanoparticles can protect, deliver, and retain the protein in the target area. This study aims to produce and characterize a topical treatment for wound healing consisting of insulin-loaded poly-DL-lactide/glycolide (PLGA) nanoparticles. Insulin-loaded nanoparticles present a mean size of approximately 500 nm and neutral surface charge. Spherical shaped nanoparticles are observed by scanning electron microscopy and confirmed by atomic force microscopy. SDS-PAGE and circular dichroism analysis demonstrated that insulin preserved its integrity and secondary structure after the encapsulation process. In vitro release studies suggested a controlled release profile. Safety of the formulation was confirmed using cell lines, and cell viability was concentration and time-dependent. Preliminary safety in vivo assays also revealed promising results.

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