Synthesis, Properties, and Biological Applications of Metallic Alloy Nanoparticles.

Metallic alloy nanoparticles are synthesized by combining two or more different metals. Bimetallic or trimetallic nanoparticles are considered more effective than monometallic nanoparticles because of their synergistic characteristics. In this review, we outline the structure, synthesis method, properties, and biological applications of metallic alloy nanoparticles based on their plasmonic, catalytic, and magnetic characteristics.

Interwoven Nitinol Stents versus Drug Eluting Stents in the Femoro-Popliteal Segment: A Propensity Matched Analysis.

BACKGROUND: Percutaneous transluminal angioplasty (PTA) is a common procedure in patients with peripheral arterial disease (PAD) affecting the femoropopliteal segment (F-P). Biomimetic nitinol stents (Supera peripheral stent, SPS) and drug eluting stents (DES) were designed to improve the longevity of F-P PTA; however, their performance has not been compared in a pragmatic setting, taking atherosclerotic plaque characteristics into account. METHODS: Overall, 296 consecutive patients (mean age: 73 y, SD: 11 y, 65% male, 68% with chronic limb threatening ischaemia) who underwent F-P PTA using SPS or DES between 2013 and 2018 were identified from a prospectively maintained institutional database. Patient and plaque characteristics, including F-P plaque characterisation based on computed tomography, were collected; 121 case matched pairs were created using a propensity score based on patient and plaque data. RESULTS: During the median two year follow up, 28% of the cohort (32% SPS vs. 24% DES, p = .07) developed target lesion restenosis (TLR) > 50%. Among the 121 case matched pairs of patients, those with SPS vs. DES were not significantly more likely to develop TLR >50% (31% vs. 27%, p = .34), or stent occlusion (13% vs. 12%, p = .85 - secondary patency rate 87% vs. 88%), have a major amputation (10% vs. 6%, p = .16), require re-intervention (14% vs. 9%, p = .12), or die (7% vs.4%, p = .31). Plaque calcification did not predict restenosis or occlusion in either stent group, both in the matched and non matched populations. Multivariable analysis adjusted for patient and plaque characteristics revealed that the main predictors of restenosis >50% at two years were female sex [odds ratio (OR): 2.05, p = .01], hypertension (OR: 2.10, p = .04) and previous F-P occlusion (OR: 1.35, p = .04). CONCLUSION: Medium term results following F-P PTA with either SPS or DES are comparable, regardless of plaque calcification and patient characteristics.

The efficacy of an intramedullary nitinol implant in the correction of claw toe or hammertoe deformities.

INTRODUCTION: A multitude of procedures has been described in the literature for the treatment of lesser toe deformities and there is currently no general consensus on the optimal method of fixation. The aim of this study is to assess the clinical and radiological outcomes of an intramedullary nitinol implant for the correction of lesser toe deformities, and to determine if the distal interphalangeal (DIP) joint and metatarsophalangeal (MTP) joint are modified during patient follow-up after correction of the PIP joint. MATERIALS AND METHODS: A prospective analysis of 36 patients with claw toe or hammertoe who were treated with an intramedullary nitinol implant. Clinical manifestations and angulation of the metatarsophalangeal, proximal and distal interphalangeal (MTP, PIP, DIP) joints were evaluated in radiographic studies preoperatively, at first medical revision post-surgery, and after a minimum of 1 year of follow-up. Complications such as non-union rate, implant rupture, and implant infection were also evaluated during follow-up. RESULTS: All patients were women with an average age of 65.5 (range 47-82) years. The average follow-up time was 2.4 (range 1-5.7) years. Fifty intramedullary nitinol implants were used. The MTP joint extension and PIP joint flexion decreased by 15.9° (95% CI - 19.11 to - 12.63) and 49.4° (95% CI - 55.29 to - 43.52), respectively, at the end of follow-up. Moreover, the DIP joint flexion increased progressively during follow-up (13.7° pre-surgery versus 35.6 in last medical check-up, 95% CI 13.24-30.57). There were four (8%) asymptomatic implant ruptures. The rate of fusion was 98%. CONCLUSION: The reduction of the PIP joint using an intramedullary nitinol implant is a good option in lesser toe deformities, with few complications and a high rate of arthrodesis. Moreover, the PIP joint reduction affects both the MTP and DIP joints.

Influence of clinical use on physical-structural surface properties and electrochemical potential of NiTi endodontic instruments.

AIM: To investigate the surface morphology and electrochemical potential of superelastic (SE), M-Wire (MW) and shape memory technology (SMT) NiTi instruments before and after single clinical use in vivo. METHODOLOGY: A total of 60 ProTaper Universal F2 (PTU-SE), ProTaper Next X2 (PTN-MW), Typhoon (TYP), Hyflex (HF) and Vortex Blue (VB), the last three SMT, and size 25, .06 taper (n = 6 of each type) files were examined. Scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS) and electrochemical potential analysis were employed before and after clinical use. Statistical analysis was performed with one-way analysis of variance and Bonferroni's post hoc test. Significance was determined at the 95% confidence level for both tests. RESULTS: SEM observations of new instruments indicated the presence of marks left by the machining process during manufacturing and EDS revealed the existence of an oxide coating on shape memory instruments. After clinical use, the five types were associated with propagation of transverse cracks 3 mm from the tip. The surface oxide layer of TYP, HF and VB instruments had microcracks in multiple directions, whilst TYP and HF had fragmentation in chip form of the oxide layer. EDS analysis demonstrated a significant reduction of the oxide layer in shape memory instruments, except for VB. Electrochemical potentials were higher for shape memory instruments than for M-Wire and superelastic NiTi instruments, respectively (P < 0.05). CONCLUSIONS: It appears that shape memory technology NiTi instruments have a dysfunctional oxide layer after clinical use. Additionally, they featured higher electrochemical potential relative to NiTi instruments manufactured from M-Wire, and conventional superelastic NiTi alloy.

Evaluation of the Effects of Fluoride Prophylactic Agents on Mechanical Properties of Nickel Titanium Wires using Scanning Electron Microscope.

INTRODUCTION: Orthodontic treatment these days is increasing in demand, and therefore, it is relatively imperative for the orthodontist to prescribe the use of fluoride-containing products, such as mouthwashes and gels, to help prevent dental caries and maintain healthy oral health. The aim of the study was to assess and evaluate the effects of fluoride prophylactic agents on mechanical properties of nickel titanium (NiTi) wires during orthodontic treatment using scanning electron microscope (SEM). MATERIALS AND METHODS: We used the commercially available round preformed NiTi orthodontic archwire (3M company) and three different mouthwash solutions, i.e., Phos-Flur gel (1.1% sodium acidulated phosphate fluoride, APF, 0.5% w/v fluoride, pH = 5.1; Colgate Oral Pharmaceuticals) and Prevident 5000 (1.1% sodium fluoride neutral agent, 0.5% w/v fluoride, pH = 7; Colgate Oral Pharmaceuticals). All the specimens were subjected to a three-point bending test on a universal testing machine. To observe the surface morphological changes, one wire from each group was randomly selected and observed under a SEM. RESULTS: It was observed that there was not much difference in the values of both modulus of elasticity and yield strength obtained after loading of stress on the wires in all the three experimental conditions. A significant difference in both modulus of elasticity and yield strength was observed during unloading of stress. Further, when the surface characteristics were observed for all the specimens using SEM images, it was observed that NiTi wires treated with Phos-Flur showed large surface defects which appeared as round, pitted areas depicting corrosion, numerous white inclusions, and overall damaged surface structure of the wire as compared with the control. CONCLUSION: Thus, fluoridated mouthwashes are essential to maintain good oral hygiene and decrease instance of caries in patients undergoing orthodontic treatment. The prophylactic usage of topical fluoride agents on NiTi wire seems to diminish the mechanical properties of the orthodontic wire that could significantly affect future treatment outcomes. CLINICAL SIGNIFICANCE: It has been proved that fluoride mouthwashes/gels do affect the structural surface qualities and strength of wires used during the orthodontic treatment irrespective of the composition of the wires. Therefore, it is the responsibility of the clinician to prescribe these prophylactic agents carefully while keeping in mind their pH so that the overall result of the treatment may not be hampered and delayed due to change in properties of the wires used.

Evolution of patency rates of self-expandable bare metal stents for endovascular treatment of femoro-popliteal arterial occlusive disease: Does stent design matter?

OBJECTIVE: To analyse the patency rates of femoro-popliteal stenting with different self-expandable Nitinol stent-designs. METHODS: Two hundred and twenty-two patients (142 (64%) male; age 72.4 ± 11.6 years) with symptomatic femoro-popliteal peripheral arterial occlusive disease (PAOD) underwent percutaneous transluminal angioplasty (PTA) and stenting with three different Nitinol stents (interwoven IW: n = 70; closed-cell CC: n = 85; open-cell OC: n = 67). One-year post-procedural target lesion revascularization (TLR_12M) rates were investigated with regard to co-morbidities: diabetes (DBM), hyperlipidaemia (HLP), hypertension (RR), coronary artery disease (CAD) and degree of calcification. RESULTS: Twelve-month follow-up data were available for 60, 69 and 50 patients in the IW, OC and CC groups (179 patients in total). The cumulative patency (IW: 52 (86.7%); OC: 50 (72.5%); CC: 23 (46.0%); P < 0.001) and the TLR_12M rates (IW: 8 (13.3%); OC: 19 (27.5%); CC: 27 (54.0%); P < 0.001) differed significantly, as did the subgroup analyses (DBM: P = 0.05; RR: P = 0.003; HLP: P = 0.005; CAD: P = 0.02; localization: P < 0.001; calcification: P < 0.001), with the best patency for the IW stent and the highest TLR_12M for the CC stent. CONCLUSION: The interwoven stent-design was superior to the standard open- and closed-cell stent-designs in endovascular treatment of femoro-popliteal PAOD in a follow-up period of 12 months. KEY POINTS: • Results of femoro-popliteal stenting are still unsatisfactory. • Comparative studies for currently available different Nitinol stent-designs are lacking. • This is a first comparative study on long-term patency of different Nitinol stent-designs. • Interwoven stent-design leads to improved long-term patency. • Interwoven stent-design leads to lower TLR than other stent-designs.

Effect of Self-Expanding Carotid Stents on Plaque Thickness and Vessel Diameter.

BACKGROUND: In vitro models have suggested that stents affect atherosclerotic plaques symmetrically because of their outward radial forces. We evaluated the effects of stents on carotid plaque and the arterial wall using carotid ultrasound in carotid stenting patients to see whether these effects were borne out in vivo. METHODS: From a carotid stent database, 30 consecutive patients were selected. All had carotid Doppler ultrasound performed pre- and poststenting. The diameters of the lumen at the level of stenotic plaque pre- and poststenting, the dorsal and ventral plaque thickness, and of the outer arterial wall diameter were measured. Plaque thickness was measured at the level of maximal stenosis. Nonparametric tests were used to determine whether the stent effect and luminal enlargement were based on wall remodeling or on total arterial expansion. RESULTS: The patients were followed for an average of 22 months. Eighteen patients were male, with an average age of 70 years. A total of 87% of patients were symptomatic ipsilateral to the side of stenosis. Nine patients had angioplasty intraprocedurally. The luminal diameter increased poststenting in the region of severe stenosis. Plaque thickness, both ventrally and dorsally, decreased poststenting, with no significant difference between the ventral and dorsal plaque effects. The outer arterial wall diameters did not change. The measured lumen in the stent increased over time poststenting. CONCLUSIONS: Self-expanding nitinol stents alter the baseline ventral and dorsal plaque to a significant degree and do not significantly affect the native arterial wall and the overall arterial diameter.

Segmental vs non-segmental thoracic pedicle screws constructs in adolescent idiopathic scoliosis: is there any implant alloy effect?

PURPOSE: The aim of this study is to understand how many anchor sites are necessary to obtain maximum posterior correction of idiopathic scoliotic curve and if the alloy of instrumentation, stainless steel or titanium, may have a role in the percent of scoliosis correction. METHODS: We reviewed 143 consecutive patients, affected by AIS (Lenke 1-2), who underwent a posterior spinal fusion with pedicle screw-only instrumentation between 2002 and 2005. According to the implant density and alloy used we divided the cohort in four groups. RESULTS: All 143 patients were reviewed at an average follow-up of 7, 2 years, the overall final main thoracic curve correction averaged 61.4%, whereas the implant density within the major curve averaged 71%. A significant correlation was observed between final% MT correction and preoperative MT flexibility and implant density. CONCLUSIONS: When stainless steel instrumentation is used non-segmental pedicle screw constructs seem to be equally effective as segmental instrumentations in obtaining satisfactory results in patients with main thoracic AIS. When the implant alloy used is titanium one, an implant density of ≥60% should be guaranteed to achieve similar results.

Temporary implantable nitinol device (TIND): a novel, minimally invasive treatment for relief of lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH): feasibility, safety and functional results at 1 year of follow-up.

OBJECTIVES: To report the first clinical experience with a temporary implantable nitinol device (TIND; Medi-Tate(®) ) for the treatment of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: In all, 32 patients with LUTS were enrolled in this prospective study, which was approved by our Institutional Ethics Committee. Inclusion criteria were: age >50 years, International Prostate Symptom Score (IPSS) of ≥10, maximum urinary flow rate (Qmax ) of ≤12 mL/s, and prostate volume of <60 mL. The TIND was implanted within the bladder neck and the prostatic urethra under light sedation, using a rigid cystoscope. The device was removed 5 days later in an outpatient setting. Demographics, perioperative results, complications (according to the Clavien system), functional results and quality of life (QoL) were evaluated. Follow-up assessments were made at 3 and 6 weeks, and 3, 6 and 12 months postoperatively. The Student's t-test, analysis of variance (anova), Kruskall-Wallis test, and simple and multiple linear regression models were used in the statistical analyses. RESULTS: The mean patient age was 69.4 years, the mean (standard deviation, sd) prostate volume was 29.5 (7.4) mL and the Qmax was 7.6 (2.2) mL/s. The median (interquartile range, IQR) IPSS was 19 (14-23) and QoL score was 3 (3-4). All the implantations were successful, with no intraoperative complications recorded. The mean operative time (sd) was 5.8 (2.5) min and the median (IQR) postoperative stay was 1 (1-2) day. All but one of the devices (96%) was removed 5 days at after implantation in an outpatient setting. Four complications (12.5%) were recorded, including urinary retention (one, 3.1%), transient incontinence due to device displacement (one, 3.1%), prostatic abscess (one, 3.1%), and urinary tract infection (one, 3.1%). Multiple regression analysis failed to identify any independent prognostic factor for complications. There were statistically significant differences in the IPSS, QoL score and Qmax when comparing pre- and postoperative results at every time point. After 12 months, the median (IQR) IPSS and QoL score were 9 (7-13) and 1 (1-2), respectively, and the mean (sd) Qmax was 12 (4.7) mL/s. The mean variations with respect to baseline conditions at the same time points were -45% for the IPSS and +67% for Qmax . At 12 months after surgery (last follow-up visit), no patients required medical therapy or surgical procedures for BPH. CONCLUSION: TIND implantation is a feasible and safe minimally invasive option for the treatment of BPH-related LUTS. The functional results are encouraging and the treatment significantly improved patient QoL. Further studies are required to assess durability of TIND results and to optimise the indications of such a procedure.

COMPRES: a prospective postmarketing evaluation of the compression anastomosis ring CAR 27(™) /ColonRing(™).

AIM: Preclinical studies have suggested that nitinol-based compression anastomosis might be a viable solution to anastomotic leak following low anterior resection. A prospective multicentre open label study was therefore designed to evaluate the performance of the ColonRing(™) in (low) colorectal anastomosis. METHOD: The primary outcome measure was anastomotic leakage. Patients were recruited at 13 different colorectal surgical units in Europe, the United States and Israel. Institutional review board approval was obtained. RESULTS: Between 21 March 2010 and 3 August 2011, 266 patients completed the study protocol. The overall anastomotic leakage rate was 5.3% for all anastomoses, including a rate of 3.1% for low anastomoses. Septic anastomotic complications occurred in 8.3% of all anastomoses and 8.2% of low anastomoses. CONCLUSION: Nitinol compression anastomosis is safe, effective and easy to use and may offer an advantage for low colorectal anastomosis. A prospective randomized trial comparing ColonRing(™) with conventional stapling is needed.

Effect of Slip Time in Forming Neo-Esophageal Stenosis After Replacement of a Thoracic Esophagus With Nitinol Artificial Esophagus.

Attempts have been made to investigate the effect of slip time of nitinol artificial esophagus for forming neo-esophageal stenosis after replacement of a thoracic esophagus with nitinol artificial esophagus in 20 experimental pigs. The pigs whose slip time was less than 90 days postoperatively had severe dysphagia (Bown's III) immediately after they were fed, and the dysphagia aggravated gradually later on (Bown's III-IV). The pigs whose slip time was more than 90 days postoperatively had mild/moderate dysphagia (Bown's I-II) immediately after they were fed, and the dysphagia relieved gradually later on (Bown's II-I-0). The ratios between the diameter of neo-esophagus in different slip time and normal esophagus were 25% (at 2 months postoperatively), 58% (at 4 months postoperatively), and 93% (at 6 months postoperatively), respectively. The relationship between nitinol artificial esophagus slip time and neo-esophageal stenosis showed a positive correlation. After replacement of a thoracic esophagus with nitinol artificial esophagus, the artificial esophageal slip time not only affected the original diameter of the neo-esophagus immediately, but also affected the neo-esophageal scar stricture forming process later on. The narrowing of neo-esophagus is caused by overgrowth of scar tissue. But there is the positive correlation between artificial esophagus slip time and neo-esophageal stenosis, so this can be a way of overcoming neo-esophageal stenosis by delaying slip time of artificial esophagus.

Laparoscopic Inguinal Hernia Repair With a Novel Hernia Mesh Incorporating a Nitinol Alloy Frame Compared With a Standard Lightweight Polypropylene Mesh.

BACKGROUND: Numerous mesh materials are available for laparoscopic inguinal hernia repair. The role of fixation of mesh in laparoscopic inguinal hernia repair remains controversial. Mesh materials have been engineered to anatomically conform to the pelvis to potentially reduce or eliminate the need for fixation. This study evaluates the outcomes of laparoscopic inguinal hernia utilizing a device consisting of a lightweight polypropylene mesh with a nitinol frame (Rebound HRD) compared with repair with lightweight polypropylene mesh with permanent tack fixation. METHODS: A prospective randomized trial evaluating the outcomes of laparoscopic inguinal hernia repair with a lightweight polypropylene mesh with a nitinol frame (N-LWM) compared with standard lightweight polypropylene mesh (LWM) was conducted. Randomization was performed at an N-LWM to LWM ratio of 2:1. Repairs were standardized to a laparoscopic extraperitoneal approach without fixation for N-LWM and titanium tack fixation for LWM repairs. Follow-up assessments were performed at 7 days, 6 months, and 1 year. Outcome measures include visual analog pain scale (VAS), Short Form 36 (SF-36), Carolinas Comfort Scale (CCS), operative details, complications, and recurrences. RESULTS: There were 47 patients that underwent laparoscopic inguinal hernia repair and adhered to study protocol (31 N-LWM, 16 LWM). The groups did not differ significantly in age, body mass index, ethnicity, or employment. The N-LWM group had bilateral mesh placed in 51.6% and LWM 43.8% (P = .76). Operative duration was similar, 59.6 ± 23.1 minutes for LWM and 62.4 ± 26.7 minutes for N-LWM (P = .705) as was mesh handling time was 5.4 ± 3.1 minutes LWM versus 7.3 ± 3.9 minutes N-LWM (P = .053). VAS, CCS, and SF-36 survey results were similar between groups. There was one recurrence (0.03%) in the N-LWM group. CONCLUSIONS: Nitinol-framed lightweight polypropylene mesh may be safely used during laparoscopic inguinal hernia repair with outcomes comparable to LWM at 1 year. N-LWM does not impact operating room time, mesh handling time, pain, recurrences, or complications.

KTP laser stapedotomy with a self-crimping, thermal shape memory Nitinol piston: follow-up study reporting intermediate-term hearing.

The aim of this study was an evaluation of the mid-term hearing results after the implantation of a self-crimping heat memory Nitinol piston in stapes surgery. The 12-month postoperative results were compared with those at a minimum of 3 years (maximum 6.7, average 4.4 years). The medical records of all 44 patients who underwent surgery with a Nitinol piston for stapes fixation between November 2005 and January 2007 were evaluated retrospectively. The prostheses used in all cases measured either 4.5 or 4.75 × 0.6 mm. We hypothesized that the 12-month postoperative hearing results would be permanent after an average follow-up of 4.4 years. Thirty-two of the 44 consecutive patients were females and 12 were males. Their mean age was 40.4 years (range 27-69). All underwent a 12-month postoperative audiometric evaluation. 38 (30 females, 8 males, average age 45, range 28-77 years) of the 44 were available for mid-term 4.4-year (minimum 3 years, maximum 6.7 years) postoperative audiometric evaluation. The mean air-bone gap (ABG) for the frequencies 0.5, 1, 2 and 3 kHz at the 12-month postoperative follow-up was 11 dB (SD 4.1) and that after an average 4.4-year postoperative evaluation was 6.4 dB (SD 3.6). The mean decrease in ABG after 12 months was 19.5 dB, and that after the average 4.4 years was 21.3 dB. ABG closure within 10 dB was achieved in 77.2 % after 12 months and in 89.5 % after the average 4.4 years. No patient with an ABG > 20 dB was recorded after the average 4.4 years. The mean air conduction threshold at 4 kHz was examined pre and postoperatively so as to indicate any possible inner ear damage. At the 12-month follow-up, the difference between the pre and postoperative values was -2.5 dB, whereas after the average 4.4 years the difference was surprisingly +13 dB. The individual AC improvements were also demonstrated with the use of Amsterdam Hearing Evaluation Plots (AHEPs). The Nitinol prosthesis allowed excellent intraoperative handling and no postoperative complication was reported. As compared with conventional stapes prostheses, the Nitinol-based SMart prosthesis is a safe and reliable stapes prosthesis. Our mid-term audiometric evaluations revealed that the audiometric parameters demonstrated a hearing improvement between the postoperative 12-month and average 4.4-year examinations. We consider the elimination of manual crimping and the use of a "non-touch" hand-held laser technique has a positive impact on the mid-term audiometric results. Most of the previous studies presented only relatively short-term (from 6 weeks up to 6-12 months) audiometric evaluations. Complications are rare, but a longer follow-up is needed to establish the long-term stability.

A novel design for steerable instruments based on laser-cut nitinol.

OBJECTIVE: Omnidirectional articulated instruments enhance dexterity. In neurosurgery, for example, the simultaneous use of 2 instruments through the same endoscopic shaft remains a difficult feat. It is, however, very challenging to manufacture steerable instruments of the requisite small diameter. We present a new technique to produce such instruments by means of laser cutting. Only 3 coaxial tubes are used. The middle tube has a cutting pattern that allows the steering forces to be transmitted from the proximal to the distal end. In this way the steering part is concealed in the wall of the tube. Large diameter articulated instruments such as for laparoscopy might benefit from the excellent tip stability provided by the same economical technology. METHOD: Coaxial nitinol tubes are laser-cut with a Rofin Stent Cutter in a specific pattern. The 3 tubes are assembled by sliding them over one another, forming a single composite tube. In a surgical simulator, the neurosurgical microinstruments and laparoscopic needle drivers were evaluated on surgical convenience. RESULTS: Simultaneous use of 2 neurosurgical instruments (1.5 mm diameter) through the same endoscopic shaft proved to be very intuitive. The tip of the steerable laparoscopic instruments (10 mm diameter) could resist a lateral force of more than 20 N. The angle of motion for either instrument was at least 70° in any direction. CONCLUSIONS: A new design for steerable endoscopic instruments is presented. It allows the construction in a range from microinstruments to 10-mm laparoscopic devices with excellent tip stability.

[Professor Iosif Khaimovich Rabkin and his priorities in roentgenoendovascular surgery].

The article is dedicated to outstanding Soviet and Russian interventional radiologist, Professor I. Kh. Rabkin and his priorities in the development of roentgenoendovascular methods of diagnosis and treatment of arterial and venous diseases. Virtually simultaneously with American surgeons, I. Kh. Rabkin not only worked out anew method of intravascular stenting of arteries with spirals made of shape-memory metal ( nitinol) but was the first in the world who in 1984 successfully stented the external iliac artery in a 56-year-old male patient with stage IV limb ischaemia.

Application and Perspectives: Magnesium Materials in Bone Regeneration.

The field of bone regeneration has always been a hot and difficult research area, and there is no perfect strategy at present. As a new type of biodegradable material, magnesium alloys have excellent mechanical properties and bone promoting ability. Compared with other inert metals, magnesium alloys have significant advantages and broad application prospects in the field of bone regeneration. By searching the official Web sites and databases of various funds, this paper summarizes the research status of magnesium composites in the field of bone regeneration and introduces the latest scientific research achievements and clinical transformations of scholars in various countries and regions, such as improving the corrosion resistance of magnesium alloys by adding coatings. Finally, this paper points out the current problems and challenges, aiming to provide ideas and help for the development of new strategies for the treatment of bone defects and fractures.

Simultaneous coil embolization and angioplasty using a self-expanding nitinol stent to treat pancreaticoduodenal artery aneurysms associated with celiac artery stenosis.

BACKGROUND: The degeneration of pancreaticoduodenal arcade vessels due to pancreaticoduodenal artery aneurysms is associated with celiac artery stenosis or occlusion. While technical advances have made it possible to treat pancreaticoduodenal arcade aneurysms (PDAA) and celiac artery stenosis by endovascular techniques, there is no consensus regarding their optimal treatment. PURPOSE: To treat pancreaticoduodenal arcade aneurysms (PDAA) by simultaneous coil embolization and celiac artery stenting, and propose indications for treating PDAA with celiac artery stenosis by this method. MATERIAL AND METHODS: We reviewed 11 patients who underwent transcatheter coil embolization (TCE) to treat PDAA. When the aneurysmal neck size was less than half of the short axis of the aneurysm we used packing only, when it was more than half of the short axis we undertook isolation. In the latter situation, when there was evidence of celiac artery stenosis, we performed celiac artery stenting using self-expandable stents. RESULTS: Ten of the 11 patients (91%) presented with celiac axis stenosis due to median arcuate ligament compression. Coil-packing of the aneurysmal sac only, thus preserving the native arterial circulation, was done in five patients, another five underwent isolation by embolization of vessels distal and proximal to the PDAA with simultaneous stenting of the stenotic celiac axis, and one patient was treated by isolation only. One patient developed acute pancreatitis. There were no other complications and all aneurysms were successfully excluded. In one patient the celiac stent thrombosed after stopping the antiplatelet regimen. CONCLUSION: TCE can be effective in patients with PDAA. In the presence of celiac artery stenosis, we recommend isolation of the aneurysms with simultaneous stenting of the stenotic celiac trunk using self-expandable stents.

Comparative effectiveness of PEEK rods versus titanium alloy rods in lumbar fusion: a preliminary report.

BACKGROUND: Posterior lumbar instruments made of titanium and its alloys could change the physiological distribution of load at the instrumented and adjacent segments, which is a main cause of implant failure, non-fusion and adjacent segment degeneration. Posterior lumbar rods made of polyetheretherketone (PEEK) which is a semirigid alternative to titanium and its alloys have been introduced in lumbar fusion. This prospective study compared the radiological and clinical outcomes of patients undergoing lumbar fusion with PEEK rods versus titanium alloy rods. METHODS: Using transpedicular fixation and lumbar fusion, 21 patients were treated with titanium alloy rods (TI group), and 20 patients with PEEK rods (PEEK group). Radiological and clinical outcomes were evaluated, including the status of the implanted instruments, fusion rate, lumbar lordosis angle (LA), disc space height (DH), visual analog score (VAS) for lower back pain (VAS-BP) and leg pain (VAS-LP), Japanese Orthopedic Association scoring system (JOA score) and complications. RESULTS: Clinical VAS-BP, VAS-LP and JOA scores were significantly improved at 3 months, 6 months, and 1 year postoperatively as compared with preoperative scores in both groups (p < 0.05), with similar levels of improvement observed at the same time points postoperatively between the two groups. The overall fusion rate was 100 % at the 1-year follow-up for both groups. No significant differences in lumbar lordosis angle were found preoperatively, 1 week and 1 year postoperatively in both groups (p > 0.05). The postoperative increase of disc space height and loss of disc space height during the follow-up showed a similar extent of change between both groups (p > 0.05). CONCLUSIONS: PEEK rods offer a similar radiological and clinical efficacy as titanium alloy rods. PEEK rods, as a semirigid implant with unique characteristics, may be an effective alternative treatment for patients with degenerative lumbar disease in lumbar fusion.

[New type titan alloy with shape memory for use in dental implantology].

The paper summarizes the results of in vitro and in vivo studies that have proved biocompatibility and medical safety of Ta and Ti-Nb-Ta-bases alloys. According to some in vitro data Ti-Nb-Ta-based alloy possesses certain advantages when comparing to Ta-based. In particular, it contributes to elevation of viability of cellular elements and to definite increase of their adhesive potential.

Fully covered removable nitinol self-expandable metal stents (SEMS) in malignant strictures of the esophagus: a multicenter analysis.

BACKGROUND: Fully covered esophageal self-expandable metallic stents (SEMS) often are used for palliation of malignant dysphagia. However, experience and data on these stents are still limited. The purpose of this multicenter study was to evaluate the efficacy and safety of fully covered nitinol SEMS in patients with malignant dysphagia. METHODS: 37 patients underwent placement of a SEMS during a 3 year period. Five patients underwent SEMS placement as a bridge to surgery: one for tracheoesophageal fistula in the setting of squamous cell carcinoma of the esophagus, one for perforation in setting of esophageal adenocarcinoma, 27 for unresectable esophageal cancer (16 adenocarcinoma, 11 squamous cell carcinoma), two for lung cancer, and one for breast-cancer-related esophageal strictures. RESULTS: SEMS placement was successful in all 37 patients. Immediate complications after stent deployment included chest pain (n = 6), severe heartburn (n = 1), and upper gastrointestinal bleeding requiring SEMS revision (n = 1). Dysphagia scores improved significantly from 3.2 ± 0.4 before stent placement to 1.4 ± 1.0 at 1 month (P < 0.0001), 1.1 ± 1.2 (P < 0.0001) at 3 months, and 1.3 ± 1.4 (P = 0.0018) at 6 months. The stent was removed in 11 patients (30%) for the following indications: resolution of stricture (n = 3), stent malfunction (n = 5), and stent migration (n = 3). After stent removal, three patients were restented, three underwent dilation, and two underwent PEG placement. Mean survival for the 37 patients after stent placement was 146.3 ± 143.6 (range, 13-680) days. CONCLUSIONS: Our study suggests that fully covered SEMS placement improve dysphagia scores in patients with malignant strictures, particularly in the unresectable population. Further technical improvements in design to minimize long-term malfunction and migration are required.