Combined Porous-Monolithic TiNi Materials Surface-Modified with Electron Beam for New-Generation Rib Endoprostheses.

TiNi alloys are very widely used materials in implant fabrication. When applied in rib replacement, they are required to be manufactured as combined porous-monolithic structures, ideally with a thin, porous part well-adhered to its monolithic substrate. Additionally, good biocompatibility, high corrosion resistance and mechanical durability are also highly demanded. So far, all these parameters have not been achieved in one material, which is why an active search in the field is still underway. In the present study, we prepared new porous-monolithic TiNi materials by sintering a TiNi powder (0-100 µm) on monolithic TiNi plates, followed by surface modification with a high-current pulsed electron beam. The obtained materials were evaluated by a set of surface and phase analysis methods, after which their corrosion resistance and biocompatibility (hemolysis, cytotoxicity, and cell viability) were evaluated. Finally, cell growth tests were conducted. In comparison with flat TiNi monoliths, the newly developed materials were found to have better corrosion resistance, also demonstrating good biocompatibility and potential for cell growth on their surface. Thus, the newly developed porous-on-monolith TiNi materials with different surface porosity and morphology showed promise as potential new-generation implants for use in rib endoprostheses.

TiNi-Based Material with Shape-Memory Effect for Surgical Treatment of Diseases of Small Intestine in Newborn and Young Children.

Alloys based on TiNi are widely used in various fields of technology and medicine. In the present work, we report on the preparation of TiNi-alloy-based wire with the shape-memory effect, which was used for compression clips for surgery. The composition and structure of the wire and its martensitic and physical-chemical properties were studied using SEM, TEM, optic microscopy, profilometry, mechanical tests, etc. The TiNi alloy was found to consist of B2 and B19' and secondary-phase particles of Ti2Ni, TiNi3 and Ti3Ni4. Its matrix was slightly enriched in Ni (50.3 at.% of Ni). A homogeneous grain structure was revealed (an average grain size of 19 ± 0.3 µm) with equal quantities of grain boundaries of special and general types. The surface oxide layer provides improved biocompatibility and promotes the adhesion of protein molecules. Overall, the obtained TiNi wire was concluded to exhibit martensitic, physical and mechanical properties suitable for its use as an implant material. The wire was then used for manufacturing compression clips with the shape-memory effect and applied in surgery. The medical experiment that involved 46 children demonstrated that the use of such clips in children with double-barreled enterostomies permitted improvement in the results of surgical treatment.

Fertility-Sparing Surgery Using Knitted TiNi Mesh Implants and Sentinel Lymph Nodes: A 10-Year Experience.

OBJECTIVES: The aim of this cohort study is to improve the procedure of fertility-sparing surgery and to assess oncological and reproductive follow-up outcomes after radical trachelectomy (RT) for cervical cancer (T1a2-1bNxM0). METHODS: We have suggested the method combining sentinel lymph nodes (SLNs) and cervicoisthmic cerclage using a superelastic knitted TiNi mesh (KTNM) implant to facilitate the primary biomechanical/retention function of the uterus. Sixty-eight consented patients, who underwent fertility-sparing surgery using both transabdominal and laparoscopic route from 2009 through 2019, were recruited in the study and prospectively followed for a mean of 69 months. RESULTS: There were no intraoperative or postoperative complications. No cervical stenoses or mesh failures were noted in all cases. The 5-year overall and recurrence-free survival rates were 100% and 97%, respectively. Two patients indicated recurrence, it occurred in 3 and 36 months. There were 19 (28%) spontaneous pregnancies, 6 resulted in full-term delivery, whereas 2 and 11 ended in miscarriage and early abortion, respectively. CONCLUSIONS: This sparing-surgery technique is turned out to be feasible and efficient as allows to achieve well oncologic and fertility outcomes, mimicking the effect of the cervix. It complements existing surgical approaches and may provide further insight into how to overcome challenges even in aggravated cases or previously failed procedures.

Biocompatibility and Clinical Application of Porous TiNi Alloys Made by Self-Propagating High-Temperature Synthesis (SHS).

Porous TiNi alloys fabricated by self-propagating high-temperature synthesis (SHS) are biomaterials designed for medical application in substituting tissue lesions and they were clinically deployed more than 30 years ago. The SHS process, as a very fast and economically justified route of powder metallurgy, has distinctive features which impart special attributes to the resultant implant, facilitating its integration in terms of bio-mechanical/chemical compatibility. On the phenomenological level, the fact of high biocompatibility of porous SHS TiNi (PTN) material in vivo has been recognized and is not in dispute presently, but the rationale is somewhat disputable. The features of the SHS TiNi process led to a multifarious intermetallic Ti4Ni2(O,N,C)-based constituents in the amorphous-nanocrystalline superficial layer which entirely conceals the matrix and enhances the corrosion resistance of the unwrought alloy. In the current article, we briefly explore issues of the high biocompatibility level on which additional studies could be carried out, as well as recent progress and key fields of clinical application, yet allowing innovative solutions.

Repair of Orbital Post-Traumatic Wall Defects by Custom-Made TiNi Mesh Endografts.

Repairs of orbital post-traumatic and extensive malignant defects remain a major surgical challenge, in view of follow-up outcomes. Incorrect surgical management of injured facial structures results in cosmetic, ophthalmic, and social aftereffects. A custom-made knitted TiNi-based mesh (KTNM) endograft was employed to overcome post-surgical complications and post-resected lesions of the orbital area. Preoperative high-resolution computed tomography (CT) imaging and CAD modelling were used to design the customized KTNM in each case. Twenty-five patients underwent surgery utilizing the suggested technique, from 2014 to 2019. In all documented cases, resolution of the ophthalmic malfunction was noted in the early period. Follow-up observation evidenced no relapsed enophthalmos, hypoglobus, or diplopia as late complications. The findings emanating from our clinical observations allow us to claim that the KTNM indicated a high level of biocompatibility. It is simply modified intraoperatively to attach any desired shape/size for implantation and can also be screw-fixed, providing a good supporting ability. The KTNM precisely renders orbitozygomatic outlines and orbital floor, thus recovering the anatomical structure, and is regarded as an attractive alternative to Ti-based meshes and plates. Additionally, we report one of the studied cases, where good functional and cosmetic outcomes have been achieved.

Sparing Surgery for the Successful Treatment of Thyroid Papillary Carcinoma Invading the Trachea: A Case Report.

Published reports on salvage treatment for trachea reconstruction after total thyroidectomy or partial tracheotomy are available, some of them using structures of the trachea itself, auricular cartilage, a musculocutaneous flap, or other methods. In our report, we emphasize the importance of a search for a new material and approach for sparing surgery. The purpose of this article is to describe a case of a successful sparing surgery in a patient with advanced thyroid papillary carcinoma invading the trachea. After total thyroidectomy in 2012, partial resection of the trachea was performed in 2014. The lesion defect was 5.5 × 2.3 cm in size, located between 4 (2nd-6th) tracheal cartilaginous rings and involving about a semicircumference. It was reconstructed with the aid of the knitted TiNi-based mesh endograft, which has been prefabricated in the sternocleidomastoid muscle and further covered with the skin draped over the wound. The tracheostoma was fully closed 6 weeks after the surgery. There were neither side effects nor complications. This kind of tracheal surgery for extensive lesions demonstrates good functional and cosmetic outcomes.

In vitro and in vivo evaluation of porous TiNi-based alloy as a scaffold for cell tissue engineering.

This study aims to look into the applicability of a porous TiNi-based shape memory alloy (SMA) scaffold as an incubator for bone marrow mesenchymal cells, hepatocytes, and pancreatic islet cells. The porous TiNi-based SMA used was fabricated using a self-propagating high-temperature synthesis (SHS) technique, in which scaffold blocks measuring 4 × 4 × 10 mm were prepared. In vitro tests were done using mesenchymal stem cells (MSC) isolated from mature bone marrow of CBA/j inbred mice, and cultured in 3 different culture media - Control medium, Osteogenic medium, and Chondrogenic medium. Hepatocytes and islet cells were isolated from the livers and pancreatic glands of Wistar rats respectively, seeded on porous TiNi-based SMA scaffolds, and cultured. The scaffolds were then implanted into the abdominal cavity of Wistar rats and later harvested, at days 7, 14, 21, and 28, post-implantation. SEM imaging was performed with pre-implanted scaffolds at day 0 and harvested scaffolds at days 7, 14, 21, and 28, post-implantation. Based on weight increase percentages, the in vitro study revealed that the osteogenic group showed a 2-fold increase, and the chondrogenic group showed a 1.33-fold increase, compared to the control group. The in vivo study, on the other hand, showed that from day 7 post-implantation, the cellular in-growth gradually invaded the inner porous structure from the periphery towards the center, and at day-28 post-implantation, all pores were closed and completely filled with cells and the extracellular matrix. The results show that porous TiNi-based SMA is a unique biocompatible incubator for cell cultures and can be successfully used for tissue bioengineering and artificial organs.

Sparing surgery with the use of TiNi-based endografts in larynx cancer patients.

BACKGROUND AND OBJECTIVES: Purpose of this study was to improve a technique of sparing surgery in patients with laryngeal cancer by using TiNi-based endografts and to achieve well functional and oncological results after laryngectomy. METHODS: Totally 120 patients with laryngeal cancer were observed (T2-3 N0-1 M0 ). We have developed a method of laryngeal reconstruction using TiNi-based endografts. All endografts show the superelastic behavior recovering the shape. All patients have undergone different types of sparing surgeries with simultaneous replacement with endografts. RESULTS: Voice function was completely saved in 112 cases and partially in 8 ones. Respiratory function was fully restored in 106 patients. The protective function of the larynx was achieved in 116 patients. CONCLUSION: The technique allowed to achieve well oncological (the 5-year and overall recurrence-free survival rates of all 120 patients were 83% and 76%, respectively) and functional (larynx function was saved in 93% of cases) outcomes after extensive and subtotal resections in patients with locally distributed larynx cancer.