scholarly journals Periprosthetic Tissue Removal in Minimally Invasive Hip Refix Procedures

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Gert Kraaij
Keyword(s):  
Minimally Invasive ◽  
Thermal Damage ◽  
Hip Prosthesis ◽  
Fibrous Tissue ◽  
Clinical Situation ◽  
Pulse Frequency ◽  
Periprosthetic Tissue ◽  
Ho:Yag Laser ◽  
Tissue Removal

An alternative to conventional revision surgery of loosened hip prostheses is a new minimally invasive refixation procedure. This procedure requires the removal of periprosthetic fibrous tissue. The aim of this preliminary study is to evaluate which technique is most suitable for minimally invasive periprosthetic tissue removal: a Ho:YAG laser or a VAPR-2 coblation system. The clinical situation of a loosened prosthesis was simulated by several cadaveric femora, each implanted with a hip prosthesis. Artificially created periprosthetic lesions were filled with a fibrous tissue substitute. Using this fibrous tissue substitute, we measured temperatures in vitro at different distances from the site of removal. Temperatures during removal were recorded both inside the fibrous tissue and in the surrounding bone. This study demonstrated that temperatures generated in the bone do not result in thermal damage. Temperatures inside the fibrous tissue are sufficiently high to remove the fibrous tissue. Using the laser instead of the coblation system for the removal of fibrous tissue resulted in higher temperatures, thus, a faster removal of fibrous tissue. Additionally, the laser takes less effort to be integrated with the new surgical instrument and, therefore, we consider it a promising tool. However, when translating the results to clinical practice, the limitations of this study should be kept in mind. The equipment was set to typical presets; different settings (pulse frequency, pulse energy, and activated time) might affect the procedure’s success and risks. Care must be taken with respect to generated temperatures at larger distances from the place of removal. The use of the Ho:YAG laser, as well as VAPR coblation, might form a small risk for thermal damage to healthy surrounding tissues. Further research on apparatus settings and removal strategy is necessary before this technique can be applied for the removal of fibrous tissue in the clinical setting.

scholarly journals Water Jet Applicator for Interface Tissue Removal in Minimally Invasive Hip Refixation: Testing the Principle and Design of Prototype

2019 ◽  
Vol 13 (2) ◽  
Author(s):  
Gert Kraaij ◽  
Arjo J. Loeve ◽  
Jenny Dankelman ◽  
Rob G. H. H. Nelissen ◽  
Edward R. Valstar
Keyword(s):  
Theoretical Analysis ◽  
Minimally Invasive ◽  
Water Pressure ◽  
Minimal Invasive ◽  
Outer Diameter ◽  
Experimental Setup ◽  
Technical Requirements ◽  
Tissue Removal ◽  
Further Development

Mechanical loosening of implants is in the majority accompanied with a periprosthetic interface membrane, which has to be removed during revision surgery. The same is true if a minimal invasive (percutaneous) refixation of a loose implant is done. We describe the requirements for a waterjet applicator for interface tissue removal for this percutaneous hip refixation technique. The technical requirements were either obtained from a literature review, a theoretical analysis, or by experimental setup. Based on the requirements, a waterjet applicator is designed which is basically a flexible tube (outer diameter 3 mm) with two channels. One channel for the water supply (diameter 0.9 mm) and one for suction to evacuate water and morcellated interface tissue from the periprosthetic cavity. The applicator has a rigid tip (length 6 mm), which directs the water flow to create two waterjets (diameter 0.2 mm), both focused into the suction channel. The functionality of this new applicator is demonstrated by testing a prototype of the applicator tip in an in vitro experimental setup. This testing has shown that the designed applicator for interface tissue removal will eliminate the risk of water pressure buildup; the ejected water was immediately evacuated from the periprosthetic cavity. Blocking of the suction opening was prevented because the jets cut through interface tissue that gets in front of the suction channel. Although further development of the water applicator is necessary, the presented design of the applicator is suitable for interface tissue removal in a minimally invasive hip refixation procedure.

Comparison of Ho:YAG laser and coblation for interface tissue removal in minimally invasive hip refixation procedures

2012 ◽  
Vol 34 (3) ◽  
pp. 370-377 ◽  
Author(s):  
Gert Kraaij ◽  
Daniel F. Malan ◽  
Huub J.L. van der Heide ◽  
Jenny Dankelman ◽  
Rob G.H.H. Nelissen ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Ho:Yag Laser ◽  
Tissue Removal

Thermal Damage Prediction for Collagenous Tissues Part I: A Clinically Relevant Numerical Simulation Incorporating Heating Rate Dependent Denaturation*

2005 ◽  
Vol 127 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Alptekin Aksan ◽  
John J. McGrath ◽  
David S. Nielubowicz,
Keyword(s):  
Heating Rate ◽  
Thermal Damage ◽  
Element Analysis ◽  
Ho:Yag Laser ◽  
Damage Prediction ◽  
Rate Dependent ◽  
Collagenous Tissue ◽  
The Stability ◽  
Collagenous Tissues

Subablative thermotherapy is frequently used for the treatment of joint instability related diseases. In this therapy, mechanically deformed collagenous tissues are thermally shrunk and the stability of the tissue is re-established. In this research, the thermal damage fields generated by three different clinical heating modalities (monopolar and bipolar radio frequency and Ho:YAG laser) are compared numerically using finite element analysis. The heating rate dependent denaturation characteristics of collagenous tissues are incorporated into the model using experimental data from in vitro experimentation with rabbit patellar tendons. It is shown that there are significant differences among the thermal damage profiles created by these modalities, explaining the main reason for the discrepancies reported in the literature in terms of the efficacy and safety of each modality. In the complementary paper, the accuracy of the model presented here is verified by in vitro experimentation with a model collagenous tissue and by quantifying the denaturation-induced birefringence change using Optical Coherence Tomography and Magnetic Resonance Imaging.

scholarly journals Feasibility of Secondary Follicle Isolation, Culture and Achievement of In-Vitro Oocyte Maturation from Superovulated Ovaries: An Experimental Proof-of-Concept Study Using Mice

2021 ◽  
Vol 10 (13) ◽  
pp. 2757
Author(s):  
Xia Hao ◽  
Amandine Anastácio ◽  
Kenny A. Rodriguez-Wallberg
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Follicular Development ◽  
Clinical Situation ◽  
Experimental Proof ◽  
Secondary Follicle ◽  
17Β Estradiol ◽  
Follicle Size ◽  
And Control

Fertility preservation through ovarian stimulation, aiming at cryopreserving mature oocytes or embryos, is sometimes unsuccessful. This clinical situation deserves novel approaches to overcome infertility following cancer treatment in patients facing highly gonadotoxic treatment. In this controlled experimental study, we investigated the feasibility of in-vitro culturing secondary follicles isolated from superovulated ovaries of mice recently treated with gonadotropins. The follicle yields of superovulated ovaries were 45.9% less than in unstimulated controls. Follicles from superovulated ovaries showed faster growth pace during the initial 7 days of culture and secreted more 17β-estradiol by the end of culture vs controls. Parameters reflecting the outcome of follicular development and oocyte maturation competence in vitro were similar between superovulated and control groups, with a similar follicle size at the end of culture and around 70% survival. Nearly half of cultured follicles met the criteria for in-vitro maturation in both groups and approximately 60% of those achieved a mature MII oocyte, similarly in both groups. Over 60% of obtained MII oocytes displayed normal-looking spindle and chromosome configurations, without significant differences between the groups. Using a validated follicle culture system, we demonstrated the feasibility of secondary follicle isolation, in-vitro culture and oocyte maturation with normal spindle and chromosome configurations obtained from superovulated mice ovaries.

scholarly journals Differential Effects of Gonadotropin-Releasing Hormone (GnRH) Pulse Frequency on Gonadotropin Subunit and GnRH Receptor Messenger Ribonucleic Acid Levels in Vitro*

Endocrinology ◽  
1997 ◽  
Vol 138 (3) ◽  
pp. 1224-1231 ◽  
Author(s):  
Ursula B. Kaiser ◽  
Andrzej Jakubowiak ◽  
Anna Steinberger ◽  
William W. Chin
Keyword(s):  
Gene Expression ◽  
Messenger Rna ◽  
Pulse Frequency ◽  
Gnrh Receptor ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Subunit Gene ◽  
Differential Effects ◽  
Messenger Ribonucleic Acid

Abstract The hypothalamic hormone, GnRH, is released and transported to the anterior pituitary in a pulsatile manner, where it binds to specific high-affinity receptors and regulates gonadotropin biosynthesis and secretion. The frequency of GnRH pulses changes under various physiological conditions, and varying GnRH pulse frequencies have been shown to regulate differentially the secretion of LH and FSH and the expression of the gonadotropin α, LHβ, and FSHβ subunit genes in vivo. We demonstrate differential effects of varying GnRH pulse frequency in vitro in superfused primary monolayer cultures of rat pituitary cells. Cells were treated with 10 nm GnRH pulses for 24 h at a frequency of every 0.5, 1, 2, or 4 h. α, LHβ, and FSHβ messenger RNA (mRNA) levels were increased by GnRH at all pulse frequencies. α and LHβ mRNA levels and LH secretion were stimulated to the greatest extent at a GnRH pulse frequency of every 30 min, whereas FSHβ mRNA levels and FSH secretion were stimulated maximally at a lower GnRH pulse frequency, every 2 h. GnRH receptor (GnRHR) mRNA levels also were increased by GnRH at all pulse frequencies and were stimulated maximally at a GnRH pulse frequency of every 30 min. Similar results were obtained when the dose of each pulse of GnRH was adjusted to maintain a constant total cumulative dose of GnRH over 24 h. These data show that gonadotropin subunit gene expression is regulated differentially by varying GnRH pulse frequencies in vitro, suggesting that the differential effects of varying GnRH pulse frequencies on gonadotropin subunit gene expression occur directly at the level of the pituitary. The pattern of regulation of GnRHR mRNA levels correlated with that of α and LHβ but was different from that of FSHβ. This suggests that α and LHβ mRNA levels are maximally stimulated when GnRHR levels are relatively high, whereas FSHβ mRNA levels are maximally stimulated at lower levels of GnRHR expression, and that the mechanism for differential regulation of the gonadotropins by varying pulse frequencies of GnRH may involve levels of GnRHR. Furthermore, these data suggest that the mechanisms whereby varying GnRH pulse frequencies stimulate α, LHβ, and GnRHR gene expression are similar, whereas the stimulation of FSHβ mRNA levels may be different.

Impact of biomineralization on resin/biomineralized dentin bond longevity in a minimally invasive approach: An “in vitro” 18-month follow-up

2021 ◽  
Vol 37 (5) ◽  
pp. e276-e289
Author(s):  
Kelly Maria Moreira ◽  
Luiz Eduardo Bertassoni ◽  
Robert Phill Davies ◽  
Felipe Joia ◽  
José Francisco Höfling ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Minimally Invasive Approach ◽  
Invasive Approach

Drug-eluting microneedles for self-administered treatment of keloids

TECHNOLOGY ◽  
2014 ◽  
Vol 02 (02) ◽  
pp. 144-152 ◽  
Author(s):  
Peng Xue ◽  
David Chen Loong Yeo ◽  
Yon Jin Chuah ◽  
Hong Liang Tey ◽  
Yuejun Kang ◽  
...  
Keyword(s):  
Clinical Supervision ◽  
Fibrous Tissue ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Keloid Fibroblast ◽  
Culture Models ◽  
Drug Eluting ◽  
Good Potential ◽  
Microneedle Patch

Keloid is a long-term dermatological scarring disease characterized by disfiguring lesions resulting from overgrowth of dense fibrous tissue. Current therapeutics are ineffective, require clinical supervision and can be costly. This study investigated the use of microneedle technology in the self-management of keloid lesions. Specifically, a microneedle patch comprising of polyethylene glycol diacrylate (PEGDA) and encapsulating 5-fluorouracil (5-FU) has been developed for transdermal delivery. The microneedle patches showed requisite mechanical strength (hardness 45 ± 11 MPa, elastic modulus 0.66 ± 0.16 GPa) and were able to puncture porcine epidermis. The choice of PEGDA substrate enabled conformability to non-planar anatomical regions (e.g. elbow), with about 50% of the loaded 5-FU released during the first 12 hours. Thereafter, the microneedle efficacy was evaluated on in vitro keloid fibroblast culture models, where 5-FU loaded microneedles effectively abolished keloid fibroblast proliferation activity. In summary, we have developed a microneedle device with a good potential as an effective, economical and self-applied therapy for keloid scars.

scholarly journals The State of the Art and Prospects for Osteoimmunomodulatory Biomaterials

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1357
Author(s):  
Andreea-Mariana Negrescu ◽  
Anisoara Cimpean
Keyword(s):  
Foreign Bodies ◽  
Structural Characteristics ◽  
Critical Role ◽  
Fibrous Tissue ◽  
Bioactive Molecules ◽  
New Bone Formation ◽  
Recent Developments

The critical role of the immune system in host defense against foreign bodies and pathogens has been long recognized. With the introduction of a new field of research called osteoimmunology, the crosstalk between the immune and bone-forming cells has been studied more thoroughly, leading to the conclusion that the two systems are intimately connected through various cytokines, signaling molecules, transcription factors and receptors. The host immune reaction triggered by biomaterial implantation determines the in vivo fate of the implant, either in new bone formation or in fibrous tissue encapsulation. The traditional biomaterial design consisted in fabricating inert biomaterials capable of stimulating osteogenesis; however, inconsistencies between the in vitro and in vivo results were reported. This led to a shift in the development of biomaterials towards implants with osteoimmunomodulatory properties. By endowing the orthopedic biomaterials with favorable osteoimmunomodulatory properties, a desired immune response can be triggered in order to obtain a proper bone regeneration process. In this context, various approaches, such as the modification of chemical/structural characteristics or the incorporation of bioactive molecules, have been employed in order to modulate the crosstalk with the immune cells. The current review provides an overview of recent developments in such applied strategies.

Assessment of Possible Thermal Damage of Tissue due to Atherectomy by Means of a Mechanical Debulking Device

2008 ◽  
Author(s):  
Ryang D. Lovik ◽  
John P. Abraham ◽  
Eph M. Sparrow
Keyword(s):  
Numerical Simulations ◽  
Thermal Injury ◽  
Thermal Damage ◽  
Threshold Value ◽  
Posterior Tibial Artery ◽  
Artery Wall ◽  
Flow Rates ◽  
Injury Index ◽  
Orbital Atherectomy

In vitro and cadaver experiments, coupled with numerical simulations, were performed to assess the possibility that orbital atherectomy might cause thermal damage of tissue. The experiments involved debulking operations on a surrogate artery and on the plaque-lined posterior tibial artery of a cadaver. Temperatures and coolant flow rates measured during these experiments enabled a numerical simulation of the debulking of a plaque-lined artery in a living human. The temperature variations from the numerical simulations were used to evaluate a thermal injury index. The resulting values of the index were found to be several orders of magnitude below the threshold value for thermal injury. It is concluded that it is extremely unlikely that the use of an orbital debulking device, the Diamondback 360°™ (Cardiovascular Systems, Inc.), can lead to thermal injury of the artery wall.

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