Fluoride-treated rare earth-free magnesium alloy ZK30: An inert and bioresorbable material for bone fracture treatment devices

Bone fractures represent a common health problem, particularly in an increasingly aging population. Bioresorbable magnesium (Mg) alloy-based implants offer promising alternatives to traditional metallic implants for the treatment of bone fractures because they eliminate the need for implant removal after healing. The Mg-Y-rare-earth (RE)-Zr alloy WE43, designed for orthopedic implants, has received European Conformity mark approval. However, currently, WE43 is not clinically used in certain countries possibly because of concerns related to RE metals. In this study, we investigated the use of a RE-free alloy, namely, Mg-Zn-Zr alloy (ZK30), as an implant for bone fractures. Hydrofluoric acid (HF) treatment was performed to improve the corrosion resistance of ZK30. HF-treated ZK30 (HF-ZK30) exhibited lower corrosion rate and higher biocompatibility than those of WE43 in in vitro experiments. After implanting a rod of HF-ZK30 into the fractured femoral bones of mice, HF-ZK30 held the bones and healed the fracture without deformation. Treatment results of HF-ZK30 were comparable to those of WE43, indicating the potential of HF-ZK30 as a bioresorbable and safe implant for bone repair.

Fentanyl-induced respiratory depression in rodents is inhibited by bioabsorbable, subcutaneous naltrexone implants at 3.5 months

The aim of this study is to determine if extended-release, bioabsorbable, subcutaneous naltrexone (NTX) implants inhibit respiratory depression after an IV injection of fentanyl. Bioabsorbable implants fabricated from two different release-controlling polymers, poly-D-L-lactide (PDLLA) and polycaprolactone (PCL), alone (placebo) or containing NTX, were subcutaneously implanted in Sprague Dawley rats. After 3.5 months of implantation, the rodents were administered an IV bolus of fentanyl through the tail vein. The placebo implant rats received a dose of 4 micrograms (mcg) - (10 mcg/kg/dose), while the NTX implanted animals received a dose of 8 mcg (20 mcg/kg/dose). The minimum active dose of fentanyl that caused a > 50 ± 2% depression in the respiration rate in the placebo implanted rodents was 4 mcg. The respiration rate of the placebo implanted rats dropped from 208 ± 14 breaths/minute at predose, to 84 ± 12 breaths/minute (p = 0.0003) at 2 min. In contrast, all NTX implanted animals easily tolerated twice the dose of 8 mcg of fentanyl without any significant reduction in respiration rate. The mean respiration rate = increased from 164 ± 22 breaths/minute at predose to 178 ± 17 breaths/minute (p = 0.24) at 2 min. The mean plasma concentrations of NTX, 3.5 months after implantation, ranged from 7.4 (±1.1) ng/mL to 80.3 (±37.5) ng/mL. Bioabsorbable implants containing NTX effectively blocked fentanyl-induced respiratory depression in rodents as compared with placebo implants, 3.5 months after implantation.

Pancreas Ligation Device for Distal Pancreatectomy: An Ex Vivo Follow-Up Porcine Study

Introduction Postoperative pancreatic fistula (POPF) is a critical complication occurring with a high incidence after distal pancreatectomy. To minimize the risk of POPF, we developed an innovative pancreas ligation device capable of closing the pancreatic stump without causing traumatic injury to the pancreatic duct and artery. We conducted an ex vivo follow-up study to compare the pressure resistance of the pancreas ligation device with that of a regular linear stapler. Materials and methods The pancreases were excised from 20 pigs and divided into two groups: ligation group (n = 10) and stapler group (n = 10). Distal pancreatectomy was performed, and the pancreatic stump was closed using either a pancreas ligation device or a regular linear stapler. The main pancreatic duct was cannulated with a 4-French catheter connected to a cannula and syringe filled with contrast medium. Using fluoroscopy detection, pressure resistance was defined as the maximum pressure without leakage from the pancreatic stump. Results No significant differences were found between the two groups regarding sex, age, body weight, or pancreatic thickness. In the ligation group, no leakage was observed at the stump in any pancreas. However, in the stapler group, six of 10 pancreases showed leakage at the staple line or into the parenchyma. Pressure resistance was significantly higher in the ligation group than in the stapler group (median: 42.8 vs. 34.3 mmHg, P = 0.023). Conclusions These findings suggest the effectiveness of a pancreas ligation device in reducing the incidence of POPF after distal pancreatectomy. Our ligation device is expected to be a useful alternative to a linear stapler for pancreatic stump closure.

Biocompatibility Assessment of Zinc Alloys as a New Potential Material for Bioabsorbable Implants for Osteosynthesis

In the last several years, zinc and its alloys have come into focus as bioabsorbable materials by qualifying themselves with an excellent corrosion rate, mechanical properties, anti-bacterial effects. and considerable biocompatibility. In this study, the biocompatibility of zinc-silver alloys containing 3.3 wt% silver (ZnAg3) was assessed by evaluating their cell viability, the proliferation rate, and the cell toxicity. Two alloys were investigated in which one was phosphated and the other was non-phosphated. The alloys were tested on human osteoblasts (hOb), which are, to a large extent, responsible for bone formation and healing processes. The performance of the phosphated alloy did not differ significantly from the non-phosphated alloy. The results showed a promising biocompatibility with hOb for both alloys equally in all conducted assays, qualifying ZnAg3 for further investigations such as in vivo studies.

Benchtop proof of concept and comparison of iron- and magnesium-based bioresorbable flow diverters

OBJECTIVE

Bioresorbable flow diverters (BRFDs) could significantly improve the performance of next-generation flow diverter technology. In the current work, magnesium and iron alloy BRFDs were prototyped and compared in terms of porosity/pore density, radial strength, flow diversion functionality, and resorption kinetics to offer insights into selecting the best available bioresorbable metal candidate for the BRFD application.

METHODS

BRFDs were constructed with braided wires made from alloys of magnesium (MgBRFD) or iron (FeBRFD). Pore density and crush resistance force were measured using established methods. BRFDs were deployed in silicone aneurysm models attached to flow loops to investigate flow diversion functionality and resorption kinetics in a simulated physiological environment.

RESULTS

The FeBRFD exhibited higher pore density (9.9 vs 4.3 pores/mm2) and crush resistance force (0.69 ± 0.05 vs 0.53 ± 0.05 N/cm, p = 0.0765, n = 3 per group) than the MgBRFD, although both crush resistances were within the range previously reported for FDA-approved flow diverters. The FeBRFD demonstrated greater flow diversion functionality than the MgBRFD, with significantly higher values of established flow diversion metrics (mean transit time 159.6 ± 11.9 vs 110.9 ± 1.6, p = 0.015; inverse washout slope 192.5 ± 9.0 vs 116.5 ± 1.5, p = 0.001; n = 3 per group; both metrics expressed as a percentage of the control condition). Last, the FeBRFD was able to maintain its braided structure for > 12 weeks, whereas the MgBRFD was almost completely resorbed after 5 weeks.

CONCLUSIONS

The results of this study demonstrated the ability to manufacture BRFDs with magnesium and iron alloys. The data suggest that the iron alloy is the superior material candidate for the BRFD application due to its higher mechanical strength and lower resorption rate relative to the magnesium alloy.

3D Printing-guided endovascular repair of enormous twisted thoracoabdominal aortic aneurysm with branch stenosis and occlusion

A 67-year-old male patient was admitted with an enormous twisted thoracoabdominal aortic aneurysm (TAAA) with multiple branch arteries stenosis and occlusion. Three-dimensional (3D) printing technology combined with mechanics was used for developing a transparent model of lesion to simulate the segment of diseased aorta. A stent graft was deployed in the 3D model to make a physician-modified stent graft (PMSGs) on table. The locations of the opening of branches were marked twice during operation. The PMSG was successfully deployed during the surgery and repaired the TAAA, with no endoleak and all the branched arteries patency in follow-up. This technique could offer precision individualized therapy and could simplify the procedure process greatly.

In Vitro Investigation of the Fixation Performance of a Bioabsorbable Magnesium ACL Interference Screw Compared to a Conventional Interference Screw

An anterior cruciate ligament (ACL) reconstruction is a common treatment for patients with ACL rupture that aims to regain pre-injury knee stability and kinematics. During the ACL reconstruction, one method to fix the graft is the use of an interference screw (IS). The IS should provide initial stability and secure the graft during the healing period. In recent years, magnesium has emerged as an alternative material to permanent metal and polymer ISs. In addition, differences in designs, such as the shape of the IS, can influence the fixation performance of the IS. Therefore, in this biomechanical experiment, two different screw designs with two ligament materials were compared in an insertion and a pull-out test at a rate of 1 mm/s. The screw designs were a conventional polymer screw and a magnesium screw. Porcine tendon and nylon rope were used as ligament materials. All tests were performed in polyurethane foam blocks with 15 PCF density (Synbone AG, Switzerland). As a result, both screw designs required an insertion torque of less than 3 Nm. There was a significant difference between the porcine and nylon rope in pull-out tests for each screw design. The magnesium screw had the highest pull-out force at 412.14 ± 50.00 N for porcine tendon and 707.38 ± 21.81 N for nylon rope. There were no significant differences in tunnel widening (narrow-wide ratio) between each ligament material. The magnesium screw showed the lowest narrow-wide tunnel ratio, implying a better ability to compress the graft to the tunnel. In conclusion, a more optimized magnesium IS design resulted in better graft fixation and an improved ACL reconstruction outcome.

An Antibacterial and Antiadhesion In Situ Forming Hydrogel with Sol-Spray System for Noncompressible Hemostasis

Noncompressible hemorrhage is a major cause of posttrauma death and occupies the leading position among potentially preventable trauma-associated deaths. Recently, multiple studies have shown that strongly adhesive materials can serve as hemostatic materials for noncompressible hemorrhage. However, the risk of severe tissue adhesion limits the use of adhesive hydrogels as hemostatic materials. Here, we report a promising material system comprising an injectable sol and liquid spray as a potential solution. Injectable sol is mainly composed of gelatin (GEL) and sodium alginate (SA), which possess hemostasis and adhesive properties. The liquid spray component, a mixture of tannic acid (TA) and calcium chloride (CaCl₂), rapidly forms an antibacterial, antiadhesive and smooth film structure upon contact with the sol. In vitro and in vivo experiments demonstrated the bioabsorbable, biocompatible, antibacterial, and antiadhesion properties of the in situ forming hydrogel with a sol-spray system. Importantly, the addition of tranexamic acid (TXA) enhanced hemostatic performance in noncompressible areas and in deep wound hemorrhage. Our study offers a new multifunctional hydrogel system to achieve noncompressible hemostasis.

Results of Anterior Cruciate Ligament Avulsion Fracture by Treatment Using Bioabsorbable Nails in Children and Adolescents

(1) Background: Anterior cruciate ligament avulsion fractures are characteristic for skeletally immature patients, and appropriate treatment is currently debated in the literature. The study aimed to evaluate the clinical and functional outcomes in patients with tibial eminence fractures treated with bioabsorbable nails in one orthopedic clinic. (2) Methods: After retrospective evaluation, we found 17 patients with tibial eminence fractures treated in orthopedic departments between January 2013 and July 2022 using bioabsorbable fixation nails. The study group comprised 12 boys and five girls aged 5 to 15.2 (average 10.1). The mean follow-up was 28 months. We diagnosed five type II fractures, ten type III fractures, and two type IV fractures according to Meyers-McKeever classification. (3) Results: We obtained a high healing rate-17 patients with the complete union on the control radiographs. We diagnosed two cases of malunion, of which one required revision surgery. Only one patient showed a slight anterior knee laxity. The treatment effect at follow-up was assessed using the Lysholm Knee Score and IKDC Score. The median Lysholm Score was 96.64 (SD 4.54), and the median IKDC Score was 84.64 (SD 3.10), which were both excellent results. (4) Conclusions: Based on our results, surgery using bioabsorbable devices for type II, III, and IV tibial eminence fractures in young individuals is an effective alternative, allowing good outcomes and restoring proper knee stability. The crucial factor for a good effect is a stable fracture fixation. Arthroscopic surgery gives good outcomes with minimal invasion. It is important not to prolong the attempts of arthroscopic reduction and to perform the open reduction to shorten the procedure's time and avoid complications.

Biocompatibility and Biological Performance of Additive-Manufactured Bioabsorbable Iron-Based Porous Interference Screws in a Rabbit Model: A 1-Year Observational Study

This study evaluated the mid-term (12-month) biomechanical, biocompatibility, and biological performance of additive-manufactured bioabsorbable iron-based interference screws (ISs). Two bioabsorbable iron IS types-manufactured using pure iron powder (iron_IS) and using pure iron powder with 0.2 wt% tricalcium phosphate (TCP_IS)-were compared with conventional metallic IS (control) using in vitro biocompatibility and degradation analyses and an in vivo animal study. The in vitro ultimate failure strength was significantly higher for iron_IS and TCP_IS than for control ISs at 3 months post-operatively; however, the difference between groups were nonsignificant thereafter. Moreover, at 3 months after implantation, iron_IS and TCP_IS increased bone volume fraction, bone surface area fraction, and percent intersection surface; the changes thereafter were nonsignificant. Iron_IS and TCP_IS demonstrated degradation over time with increased implant surface, decreased implant volume, and structure thickness; nevertheless, the analyses of visceral organs and biochemistry demonstrated normal results, except for time-dependent iron deposition in the spleen. Therefore, compared with conventional ISs, bioabsorbable iron-based ISs exhibit higher initial mechanical strength. Although iron-based ISs demonstrate high biocompatibility 12 months after implantation, their corrosive iron products may accumulate in the spleen. Because they demonstrate mechanical superiority along with considerable absorption capability after implantation, iron-based ISs may have potential applications in implantable medical-device development in the future.

Late tibial interference screw extrusion following anterior cruciate ligament reconstruction: A case report

INTRODUCTION

Interference screws are used as back-up fixation in anterior cruciate ligament reconstructions. Historically these were composed of metal, but recently surgeons have switched to using bioabsorbable screws as they cause less symptoms and are biomedically advantageous. Usually these screws are absorbed by the body within one to two years after surgery.

CASE PRESENTATION

A 32-year-old male presented with aseptic extrusion of his intact tibial bioabsorbable interference screw eight years following successful anterior cruciate ligament reconstruction.

MANAGEMENT AND OUTCOMES

Patient underwent laboratory evaluation and magnetic resonance imaging to rule out infection as an underlying cause. He went on to heal the wound without complication.

CONCLUSION

Late aseptic extrusion of tibial interference screw can occur; however, infectious etiologies should be carefully ruled out.

Mechanical properties and degradation process of biliary self-expandable biodegradable stents

OBJECTIVES

The clinical outcomes and prevalence of adverse events associated with biliary biodegradable stents (BS) can differ according to degradation process and time. The aim of this study was to observe the degradation process and time of different BS prototypes, and to evaluate sequential changes in their mechanical properties.

METHODS

Using an in vitro bile flow phantom model, we compared degradation time, radial force changes, and morphologic changes among four different BS prototypes: polydioxanone (PDO) BS, polyglycolide (PGA) BS, polydioxanone/poly-l-lactic acid (PDO/PLLA) sheath-core BS, and polydioxaone/magnesium (PDO/Mg) sheath-core BS. Using an in vivo swine bile duct dilation model, we performed a direct peroral cholangioscopy (DPOC) examination to observe the biodegradation process and related adverse events at regular intervals.

RESULTS

In the bile flow phantom model, the PGA BS and PDO/Mg BS prototypes showed rapid radial force reduction and morphological changes and complete degradation within six weeks. PDO/PLLA BS maintained high radial force and kept their original shape for longer than the PDO BS, up to 16 weeks. A total of 24 BS were inserted into the dilated bile ducts of 12 swine. In this animal model, DPOC examination revealed that PDO BS and PDO/PLLA BS maintained their original shapes for approximately 12 weeks, but PDO BS showed a greater degree of fragmentation and induced biliary stones and bile duct obstruction.

CONCLUSION

Our results showed that PDO/PLLA BS maintained their original shape and radial force for a relatively long time and minimized adverse events.

Biocompatibility and Biological Performance Evaluation of Additive-Manufactured Bioabsorbable Iron-Based Porous Suture Anchor in a Rabbit Model

This study evaluated the biocompatibility and biological performance of novel additive-manufactured bioabsorbable iron-based porous suture anchors (iron_SAs). Two types of bioabsorbable iron_SAs, with double- and triple-helical structures (iron_SA_2_helix and iron_SA_3_helix, respectively), were compared with the synthetic polymer-based bioabsorbable suture anchor (polymer_SAs). An in vitro mechanical test, MTT assay, and scanning electron microscope (SEM) analysis were performed. An in vivo animal study was also performed. The three types of suture anchors were randomly implanted in the outer cortex of the lateral femoral condyle. The ultimate in vitro pullout strength of the iron_SA_3_helix group was significantly higher than the iron_SA_2_helix and polymer_SA groups. The MTT assay findings demonstrated no significant cytotoxicity, and the SEM analysis showed cells attachment on implant surface. The ultimate failure load of the iron_SA_3_helix group was significantly higher than that of the polymer_SA group. The micro-CT analysis indicated the iron_SA_3_helix group showed a higher bone volume fraction (BV/TV) after surgery. Moreover, both iron SAs underwent degradation with time. Iron_SAs with triple-helical threads and a porous structure demonstrated better mechanical strength and high biocompatibility after short-term implantation. The combined advantages of the mechanical superiority of the iron metal and the possibility of absorption after implantation make the iron_SA a suitable candidate for further development.

Computed Tomography Imaging of BioComposite Interference Screw After ACL Reconstruction With Bone-Patellar Tendon-Bone Graft

Background:

Bioabsorbable interference screws tend to have high resorption rates after anterior cruciate ligament (ACL) reconstruction; however, no studies have examined screws composed of 30% biphasic calcium phosphate and 70% poly-d-lactide (30% BCP/70% PLDLA).

Purpose:

To evaluate femoral and tibial tunnel widening and resorption of 30% BCP/70% PLDLA interference screws and replacement with bone at 2 to 5 years after ACL reconstruction using bone–patellar tendon–bone (BTB) autograft.

Study Design:

Case series; Level of evidence, 4.

Methods:

Included were 20 patients who had undergone ACL reconstruction using BTB autograft and were reevaluated 2 to 5 years after surgery using computed tomography scans. Tunnel measurements were obtained from computed tomography scans in the sagittal and coronal planes and were compared with known tunnel measurements based on operative reports. These images and measurements were used to assess tunnel widening, resorption of the 30% BCP/70% PLDLA screw, its replacement with bone, and possible cyst formation. Paired t tests were used to compare initial and final femoral and tibial tunnel measurements.

Results:

The cross-sectional area of the femoral tunnel decreased at the aperture (P = .03), middle (P = .0002), and exit (P < .0001) of the tunnel compared with the initial femoral tunnel size, and the tibial tunnel cross-sectional area decreased at the aperture (P < .0001) and exit (P = .01) of the tunnel compared with the initial tibial tunnel size. Bone formation was observed in 100% of femoral tunnels and 94.7% of tibial tunnels. Screw resorption was 100% in the femur and 94.7% in the tibia at the final follow-up. Cysts were noted around the femoral tunnel in 2 patients (5.1%).

Conclusion:

The 30% BCP/70% PLDLA interference screws used for ACL reconstruction using BTB autograft had high rates of resorption and replacement with bone, and there were no increases in tunnel size at 2 to 5 years postoperatively. The authors observed a low rate of cyst formation and no other adverse events stemming from the use of this specific biointerference screw, suggesting that this type of screw is a reasonable option for graft fixation with minimal unfavorable events and a reliable resorption profile.

Microstructural and Corrosion Properties of Hydroxyapatite Containing PEO Coating Produced on AZ31 Mg Alloy

In this work, the composition of an electrolyte was selected and optimized to induce the formation of hydroxyapatite during Plasma electrolytic oxidation (PEO) treatment on an AZ31 alloy for application in bioabsorbable implants. In detail, the PEO process, called PEO-BIO (Plasma Electrolytic Oxidation-Biocompatible), was performed using a silicate-phosphate-based electrolyte with the addition of calcium oxide in direct-current mode using high current densities and short treatment times. For comparison, a known PEO process for producing anticorrosive coatings, called standard, was applied on the same alloy. The coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and XPS analyses. The corrosion performance was evaluated in simulated body fluid (SBF) at 37 °C. The coating produced on the PEO-BIO sample was porous and thicker than the standard PEO one, with zones enriched in Ca and P. The XRD analysis showed the formation of hydroxyapatite and calcium oxides in addition to magnesium-silicon oxide and magnesium oxide in the PEO-BIO sample. The corrosion resistance of PEO-BIO sample was comparable with that of a traditional PEO treated sample, and higher than that of the untreated alloy.

Effects of Two Melt Extrusion Based Additive Manufacturing Technologies and Common Sterilization Methods on the Properties of a Medical Grade PLGA Copolymer

Although bioabsorbable polymers have garnered increasing attention because of their potential in tissue engineering applications, to our knowledge there are only a few bioabsorbable 3D printed medical devices on the market thus far. In this study, we assessed the processability of medical grade Poly(lactic-co-glycolic) Acid (PLGA)85:15 via two additive manufacturing technologies: Fused Filament Fabrication (FFF) and Direct Pellet Printing (DPP) to highlight the least destructive technology towards PLGA. To quantify PLGA degradation, its molecular weight (gel permeation chromatography (GPC)) as well as its thermal properties (differential scanning calorimetry (DSC)) were evaluated at each processing step, including sterilization with conventional methods (ethylene oxide, gamma, and beta irradiation). Results show that 3D printing of PLGA on a DPP printer significantly decreased the number-average molecular weight (Mn) to the greatest extent (26% Mn loss, p < 0.0001) as it applies a longer residence time and higher shear stress compared to classic FFF (19% Mn loss, p < 0.0001). Among all sterilization methods tested, ethylene oxide seems to be the most appropriate, as it leads to no significant changes in PLGA properties. After sterilization, all samples were considered to be non-toxic, as cell viability was above 70% compared to the control, indicating that this manufacturing route could be used for the development of bioabsorbable medical devices. Based on our observations, we recommend using FFF printing and ethylene oxide sterilization to produce PLGA medical devices.

Bioabsorbable magnesium screw fixation for tibial tubercle osteotomy; a preliminary study

BACKGROUND AND AIM

Metallic screws are commonly used to fix tibial tubercle osteotomies (TTO). However, hardware removal late after osteotomy union is one of the most common causes of reoperation following TTOs. The use of bioabsorbable screws may eliminate secondary surgeries, but there is no study on their use in this indication. The purpose of this retrospective study was to evaluate the safety and efficacy of bioabsorbable magnesium (Alloy: MgYREZr) screws in tibial tubercle osteotomy (TTO) fixation.

METHODS

Ten patients with objective patellar instability who underwent distal realignment procedure using Fulkerson TTO were retrospectively reviewed. The osteotomy was secured with two parallel 4.8 mm magnesium screws in all patients. Kujala score and Lysholm knee score were used to assess the functional outcomes before and after the operation. Union of the osteotomy, displacement, and other imaging findings were evaluated with serial knee radiographs during the follow-up.

RESULTS

There were five male and five female patients with a mean age of 23.4±9.2 years (range, 15-45). The mean follow-up duration was 11.5±3.2 months (range,6-17 months). The osteotomy united in all cases at an average of 3 months. No infection or wound healing problems were seen. A significant increase in Kujala (p:.005) and Lysholm knee scores (p:.005) were recorded in all patients.

CONCLUSION

The findings support that bioabsorbable magnesium screws can be safely used as an alternative fixation technique in TTO. Furthermore, it provides the advantage to eliminate the need for implant removal.

Arthroscopic repair of posterosuperior rotator cuff tears with bioabsorbable patch augmentation: a magnetic resonance-controlled case series with 1-year follow-up

Background

Among many advances in the treatment of rotator cuff tears, arthroscopic augmentation techniques with patches of various biological and synthetic graft materials have been introduced to reinforce the repair. However, structural and functional outcomes after patch augmentation vary, and reinforcing the tendon healing remains a challenge. The aim of this study was to evaluate clinical and radiologic outcomes 1 year after arthroscopic posterosuperior (PS) rotator cuff repair with bioabsorbable patch augmentation.

Methods

From October 2014 to December 2017, all patients with PS rotator cuff tears undergoing arthroscopic repair with patch augmentation using a resorbable, biologically derived poly-4-hydroxybutyrate patch (Biofiber; Wright, Memphis, TN, USA) were enrolled in this study. Only full-thickness PS lesions with ≥1 of the following tear patterns were augmented with a patch and were the subject of this study: large U- and L-shaped tear, transtendinous tear, delamination, and fraying of the bursal layer. Patients were examined preoperatively and at 1 year postoperatively with a standardized examination protocol and magnetic resonance imaging (MRI).

Results

Sixteen patients were included in this study; 1 patient was lost to follow-up. One patient only underwent clinical follow-up. We detected 1 repair failure (6.7%) with dislocation of the lateral-row anchors on computed tomography scanning at 3 months postoperatively. MRI was performed in 14 patients after 1 year; in all of them, the cuff repair was intact. The Sugaya tendon integrity score was 1.7 ± 0.9. The Constant-Murley score improved from 44 to 89 points (P < .001). Muscular strength improved in the supraspinatus (from 2.6 to 4.8), infraspinatus (from 3.2 to 4.9), and subscapularis (from 4 to 4.9) (all P < .001). Overall, patient satisfaction was high (3.6 ± 0.6).

Discussion

This small-sized case series is the first to prospectively assess clinical and radiologic outcomes after patch augmentation of PS rotator cuff tears using bioabsorbable poly-4-hydroxybutyrate patches. Good to excellent structural and functional outcomes were observed with a low retear rate (6.7%) and good tendon integrity on 1-year postoperative MRI, and the graft did not cause any complications. The use of bioabsorbable patches could be beneficial when unfavorable PS tear patterns are encountered in which a stable repair of the full tendon thickness at its insertion is otherwise difficult to reach.

Comparison of Bioabsorbable Steroid-Eluting Sinus Stents Versus Nasopore After Endoscopic Sinus Surgery: A Multicenter, Randomized, Controlled, Single-Blinded Clinical Trial

OBJECTIVES

The aim of this study was to compare the efficacy of bioabsorbable steroid-eluting sinus stents versus absorbable Nasopore packs after endoscopic sinus surgery (ESS) for the treatment of chronic rhinosinusitis (CRS).

METHODS

One hundred eighty-one patients with CRS who underwent ESS were randomly assigned to receive a steroid-eluting sinus stent in one ethmoid sinus cavity, whereas the contralateral control side received a Nasopore pack. Endoscopic evaluations were performed 14, 30, and 90 days after the ESS. Postoperative intervention, polyp formation, adhesions, and middle turbinate (MT) position were assessed as efficacy outcomes.

RESULTS

The stents were successfully deployed in all 181 sinuses. Thirty days after the ESS, the stents significantly reduced the need for surgical intervention compared to the Nasopore (P < .0001). The percentage of cases with polyp formation was significantly lower on the stent sides compared with the Nasopore sides (P < .0001) at 14, 30, and 90 days after ESS. The percentage of severe adhesion was significantly lower on the stents sides than on the Nasopore sides at postoperative day 90 (P = .0003), whereas they were not significantly lower at postoperative days 14 and 30. There were no significant differences between the stent sides and the Nasopore sides regarding the frequency of MT lateralization at all end points. No device-related adverse events occurred.

CONCLUSIONS

Our study demonstrated significant improvement in the early postoperative outcomes by reducing the need for postoperative surgical intervention and polyp formation using steroid-eluting stents when compared with absorbable Nasopore packs. The steroid-eluting sinus stents and the Nasopore packs were each effective in preserving the ethmoid sinus patency and in preventing MT lateralization. A further prospective cohort study with long-term postoperative outcomes is warranted.

Bioabsorbable Versus Titanium Screws in Anterior Cruciate Ligament Reconstruction Using Hamstring Autograft: A Prospective, Randomized Controlled Trial With 13-Year Follow-up

BACKGROUND

Bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been a popular choice, with theoretical advantages in imaging and surgery. Titanium and poly-L-lactic acid with hydroxyapatite (PLLA-HA) screws have been compared, but with less than a decade of follow-up.

PURPOSE/HYPOTHESIS

The purpose was to compare long-term outcomes of hamstring autograft ACLR using either PLLA-HA screws or titanium screws. We hypothesized there would be no difference at 13 years in clinical scores or tunnel widening between PLLA-HA and titanium screw types, along with high-grade resorption and ossification of PLLA-HA screws.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Forty patients undergoing ACLR were randomized to receive either a PLLA-HA screw or a titanium screw for ACL hamstring autograft fixation. Blinded evaluation was performed at 2, 5, and 13 years using the International Knee Documentation Committee score, Lysholm knee score, and KT-1000 arthrometer. Magnetic resonance imaging (MRI) was performed at 2 or 5 years and 13 years to evaluate tunnel volumes, ossification around the screw, graft integration, and cyst formation. Computed tomography (CT) of patients with PLLA-HA was performed at 13 years to evaluate tunnel volumes and intratunnel ossification.

RESULTS

No differences were seen in clinical outcomes at 2, 5, or 13 years between the 2 groups. At 13 years, tibial tunnel volumes were smaller for the PLLA-HA group (2.17 cm³) compared with the titanium group (3.33 cm³; P = .004). By 13 years, the PLLA-HA group had complete or nearly complete resorption on MRI or CT scan.

CONCLUSION

Equivalent clinical results were found between PLLA-HA and titanium groups at 2, 5, and 13 years. Although PLLA-HA screws had complete or nearly complete resorption by 13 years, tunnel volumes remained largely unchanged, with minimal ossification.

Magnesium Bioabsorbable Screw Fixation of Radial Styloid Fractures: Case Report

Background  Several types of fixation materials may be used for the radial styloid fractures such as Kirschner wire fixation, screw fixation, volar plate fixation, and fragment-specific radial buttress plate fixation. However, each of these fixation techniques has certain complications usually related to either the surgical dissection or the application of fixation and symptomatic permanent hardware. Implant removal secondary to irritation of prominent screw heads or bulky plates is not uncommon after radial styloid fracture fixation. Case Description  Herein, two patients with an isolated radial styloid fracture who were treated with bioabsorbable magnesium (alloy: MgYREZr) screws are presented. In both patients, the fracture union was achieved without any complication and need for implant removal. Literature Review  This is the first report on the use of magnesium screws for this indication. Clinical Relevance  Magnesium bioabsorbable compression screw fixation may be an alternative solution that eliminates removal operations due to symptomatic hardware in radial styloid fractures.

Unfavourable early outcomes of total trapeziectomy with RegJoint™ interposition: a report of 38 osteoarthritic hands in 34 patients

This retrospective study analysed the results of total trapeziectomy with RegJoint™ interposition in 38 osteoarthritic hands in 34 patients. Patients were evaluated preoperatively, at follow-up visits, and at a mean final follow-up of 33 months (range 20-53) with plain radiographs, computed tomography, as well as with subjective and objective evaluations. Pain decreased and subjective outcomes and function improved significantly. Computed tomography 18 months after operation showed osteolysis in 24 cases. Three patients developed wrist pain 12-18 months after operation with MRI findings of a foreign-body reaction in each case. One of these patients was scheduled for revision surgery. Although the clinical results were satisfactory, the risk of foreign-body reaction and osteolysis is noteworthy. We conclude that the use of RegJoint™ should be reconsidered since the implant probably offers no benefit in the treatment of trapeziometacarpal osteoarthritis. Level of evidence: IV.

In-office Placement of Mometasone Furoate Sinus Implants for Recurrent Nasal Polyps: A Pooled Analysis

Background

A mometasone furoate (MF) sinus implant (1350 mcg) was evaluated in 2 randomized controlled trials (RCTs) in 400 adults with nasal polyps (NP) who were candidates for revision endoscopic sinus surgery (RESS). We conducted a pooled analysis to evaluate the efficacy of MF implant in specific subgroups of NP patients.

Methods

Pooled data from 2 RCTs for 375 patients were analyzed across prespecified subjective and objective end points through day 90.

Results

At day 90, patients receiving implants and MF nasal spray (MFNS) experienced significant improvements in nasal obstruction/congestion (NO/C) score ( P = .0095), bilateral polyp grade (BPG, P = .0008), and ethmoid sinus obstruction ( P < .0001) compared to control using MFNS alone. Fewer treatment than control patients remained candidates for RESS (41.0% vs 69.3%, P < .0001). All subgroups experienced significant treatment effects, except NO/C in smokers ( P = .0509) and patients without altered smell ( P = .1873). Subgroups without asthma and with only 1 prior ESS experienced largest treatment effect on NO/C, and those with recent surgery <24 months and BPG >5 showed largest effect on endoscopic end points and RESS. Control patients with ESS <24 months were at 7 times highest risk for RESS ( P < .0001). One (0.4%) patient experienced implant-related serious adverse event (epistaxis).

Conclusion

On pooled analysis, MF implants with MFNS showed more favorable results than MFNS alone across several subjective and objective end points at day 90 and may play an important role in management of NP patients, especially those who have allergic rhinitis, expanded polyposis, altered smell, or had most recent ESS < 24 months.

Biodegradable biliary stents preferable to plastic stent therapy in post-cholecystectomy bile leak and avoid second endoscopy

BACKGROUND

The treatment of post-cholecystectomy bile leak is endoscopic retrograde cholangiography (ERC) with plastic stent (PS) insertion combined with external drainage. Self-expanding biodegradable biliary stents (BDBS) have only recently become available.

AIM

The aim was to compare success rate, adverse events and costs of BDBS with PS in the treatment of post-cholecystectomy cystic duct leak Materials and methods: Patients recruited prospectively for treatment with BDBS during the period 2014-2017 were compared to a control group treated with PS in a non-randomized setting.

RESULTS

Altogether 32 patients (median age 68, range 33-88, 59% male) were treated for Strasberg A bile leak over a period of 3.5 years, accounting for 1.8% of all ERCs. Eight patients were treated with BDBS and 24 with PS. Treatment with BDBS was safe; rate of readmissions and 30-day adverse events were 13% in both groups. There was no statistical difference in the clinical success rate. All cases with laparoscopic lavation or re-ERC with stent exchange occurred in the PS group. Total drain output was lower in BDBS patients (330ml vs 83ml, p=.002). All PS patients required another endoscopy for stent removal, whereas all BDBS patients were spared repeated endoscopy.

CONCLUSION

Treatment of cystic duct leak with BDBS is highly successful and as safe as traditional treatment with PS. The most obvious benefit of BDBS is that it avoids stent removal. The lower drain output after ERC with a trend for fewer unplanned interventions may indicate more efficient leak resolution with the large bore BDBS.

3D-Printed PCL/PLA Composite Stents: Towards a New Solution to Cardiovascular Problems

Biodegradable stents (BRS) offer enormous potential but first they must meet five specific requirements: (i) their manufacturing process must be precise; (ii) degradation should have minimal toxicity; (iii) the rate of degradation should match the recovery rate of vascular tissue; (iv) ideally, they should induce rapid endothelialization to restore the functions of vascular tissue, but at the same time reduce the risk of restenosis; and (v) their mechanical behavior should comply with medical requirements, namely, the flexibility required to facilitate placement but also sufficient radial rigidity to support the vessel. Although the first three requirements have been comprehensively studied, the last two have been overlooked. One possible way of addressing these issues would be to fabricate composite stents using materials that have different mechanical, biological, or medical properties, for instance, Polylactide Acid (PLA) or Polycaprolactone (PCL). However, fashioning such stents using the traditional stent manufacturing process known as laser cutting would be impossible. Our work, therefore, aims to produce PCL/PLA composite stents using a novel 3D tubular printer based on Fused Deposition Modelling (FDM). The cell geometry (shape and area) and the materials (PCL and PLA) of the stents were analyzed and correlated with 3T3 cell proliferation, degradation rates, dynamic mechanical and radial expansion tests to determine the best parameters for a stent that will satisfy the five strict BRS requirements. Results proved that the 3D-printing process was highly suitable for producing composite stents (approximately 85⁻95% accuracy). Both PCL and PLA demonstrated their biocompatibility with PCL stents presenting an average cell proliferation of 12.46% and PLA 8.28% after only 3 days. Furthermore, the PCL/PLA composite stents demonstrated their potential in degradation, dynamic mechanical and expansion tests. Moreover, and regardless of the order of the layers, the composite stents showed (virtually) medium levels of degradation rates and mechanical modulus. Radially, they exhibited the virtues of PCL in the expansion step (elasticity) and those of PLA in the recoil step (rigidity). Results have clearly demonstrated that composite PCL/PLA stents are a highly promising solution to fulfilling the rigorous BRS requirements.

Fully Bioabsorbable Natural-Materials-Based Triboelectric Nanogenerators

Implantable medical devices provide an effective therapeutic approach for neurological and cardiovascular diseases. With the development of transient electronics, a new power source with biocompatibility, controllability, and bioabsorbability becomes an urgent demand for medical sciences. Here, various fully bioabsorbable natural-materials-based triboelectric nanogenerators (BN-TENGs), in vivo, are developed. The "triboelectric series" of five natural materials is first ranked, it provides a basic knowledge for materials selection and device design of the TENGs and other energy harvesters. Various triboelectric outputs of these natural materials are achieved by a single material and their pairwise combinations. The maximum voltage, current, and power density reach up to 55 V, 0.6 µA, and 21.6 mW m^-2 , respectively. The modification of silk fibroin encapsulation film makes the operation time of the BN-TENG tunable from days to weeks. After completing its function, the BN-TENG can be fully degraded and resorbed in Sprague-Dawley rats, which avoids a second operation and other side effects. Using the proposed BN-TENG as a voltage source, the beating rates of dysfunctional cardiomyocyte clusters are accelerated and the consistency of cell contraction is improved. This provides a new and valid solution to treat some heart diseases such as bradycardia and arrhythmia.

Bioabsorbable poly-L/D-lactide (96/4) scaffold arthroplasty (RegJoint™) for trapeziometacarpal osteoarthritis: a 3-year follow-up study

The poly-L/D-lactide joint scaffold (RegJoint™) has recently been associated with adverse tissue reactions and osteolysis after partial trapeziectomy for trapeziometacarpal osteoarthritis. Twenty-two of 23 patients previously operated on with this scaffold were re-examined at a mean follow-up of 3.3 years (range 36-53 months). Overall, the results showed an unacceptably high rate of adverse tissue reactions related to the degradation process of the implant, resulting in a revision procedure in three patients. At final follow-up, at which point the implant had completely degraded, there were no signs of ongoing adverse tissue reactions. There was a significant decrease in pain, increase in strength and subjective improvement in function at final follow-up compared with the pre-operative results in patients who had not undergone revision surgery. However, owing to the high incidence of adverse tissue reactions, the use of the implant has been discontinued in the treatment of trapeziometacarpal osteoarthritis.

LEVEL OF EVIDENCE

IV.

The effect of Mg-Ca-Sr alloy degradation products on human mesenchymal stem cells

Biodegradable Mg alloys have the potential to replace currently used metallic medical implant devices, likely eliminating toxicity concerns and the need for secondary surgeries, while also providing a potentially stimulating environment for tissue growth. A recently developed Mg-Ca-Sr alloy possesses advantageous characteristics over other Mg alloys, having a good combination of strength and degradation behavior, while also displaying potentially osteogenic properties. To better understand the effect of alloy degradation products on cellular mechanisms, in vitro studies using human bone marrow-derived mesenchymal stem cells were conducted. Ionic products of alloy dissolution were found to be nontoxic but changed the proliferation profile of stem cells. Furthermore, their presence changed the progress of osteogenic development, while concentrations of Mg in particular appeared to induce stem cell differentiation. The work presented herein provides a foundation for future alloy design where structures can be tailored to obtain specific implant performance. These potentially bioactive implants would reduce the risks for patients by shortening their healing time, minimizing discomfort and toxicity concerns, while reducing hospital costs. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 697-704, 2018.

Bioabsorbable self-retaining PLA/nano-sized β-TCP cervical spine interbody fusion cage in goat models: an in vivo study

STUDY DESIGN

This is an experimental animal study.

OBJECTIVE

The objective of this study was to compare an anterior cervical discectomy and interbody fusion of a novel polylactide/nano-sized β-tricalcium phosphate (PLA/nβ-TCP) bioabsorbable self-retaining cervical fusion cage (BCFC) with an autologous bone graft and polyetheretherketone (PEEK) cages.

BACKGROUND

Although PLA cervical cages have potential advantages compared with traditional materials, they are not currently routinely used in spine surgery because of undesirable effects such as the lack of osteoconductivity and osteolysis around the implant. This study involved the manufacturing of a bioabsorbable cage from PLA/nβ-TCP that was then used as a device for anterior cervical discectomy and fusion (ACDF) on a goat cervical spine fusion model.

MATERIALS AND METHODS

Eighteen goats underwent C3/C4 discectomy and were randomly divided into three groups based on the following methods: Group A (n=6), an autologous bone graft; Group B (n=6), PEEK cage filled with an autologous graft; and Group C (n=6), BCFC filled with an autologous iliac bone. Radiography was performed preoperatively and postoperatively and at 1, 4, 8, and 12 weeks after the operation. Disc space height (DSH) was measured at the same time. After 12 weeks, the fused segments were harvested and evaluated with functional radiographic views, biomechanical testing, and histological analyses.

RESULTS

Over a 12-week period, the BCFC and PEEK cage groups exhibited significantly higher DSH values than the bone graft group. Additionally, the BCFC group yielded a significantly lower range of motion in axial rotation than both the autologous bone graft and PEEK cage groups. A histologic evaluation revealed an increased intervertebral bone volume/total volume ratio and better interbody fusion in the BCFC group than in the other groups.

CONCLUSION

The BCFC device exhibited better results than the autologous bone graft and PEEK cages in single-level ACDF models in vivo. This device may be a potential alternative to the current PEEK cages.

Safety and efficacy of a bioabsorbable fluticasone propionate-eluting sinus dressing in postoperative management of endoscopic sinus surgery: a randomized clinical trial

BACKGROUND

Postoperative wound healing after endoscopic sinus surgery (ESS) in patients with chronic rhinosinusitis (CRS) is an important factor in procedural success. Local steroids and separation of opposing mucosa are commonly implemented to optimize healing. A bioabsorbable, fluticasone propionate (FP)-eluting implant, SinuBand FP, was assessed for its safety and efficacy when used in patients with CRS and nasal polyps, who were indicated for ESS including bilateral anterior and posterior ethmoidectomy.

METHODS

A first-in-human, randomized, partially double-blind, single-tertiary-referral-center, controlled trial enrolling 30 patients receiving 2 of 3 treatments (1 per sinus, intrapatient control): SinuBand FP, SinuBand (without FP), or standard nasal pack (Merocel®). Primary outcome measures were local safety, ocular safety (intraocular pressure [IOP], lens opacity), and 24-hour urine cortisol. Secondary measures (evaluated by independent review of postoperative video endoscopies) were ethmoid inflammation, polyp score, adhesion formation, and Lund-Kennedy score. Patient-reported outcomes of postoperative pain, nasal congestion, and nasal discharge were collected.

RESULTS

Of 30 enrolled patients (used for safety analysis), 27 patients completed the trial. SinuBand FP showed local safety, ocular safety, and no significant change in 24-hour urine cortisol. SinuBand FP showed a trend to do better concerning inflammation. Concerning polyp score SinuBand FP did significantly better compared to Merocel (p = 0.03). No significance compared to SinuBand without corticosteroids (p = 0.97). Adhesions were comparable across treatments. Patient reported pain was nominally lower in the SinuBand group.

CONCLUSION

SinuBand FP was well tolerated and showed evidence of efficacy. A larger study is needed to further evaluate and confirm the benefits of SinuBand FP.

Fabrication and characterization of shape memory polymers based bioabsorbable biomedical drug eluting stent

Present investigation deals with, tacrolimus eluting, self-expandable, biodegradable stent fabricated by solvent casting method. The design was based on shape memory polymers, which possess the ability to memorize temporary shape that can substantially differ from their initial permanent shape. A set of biodegradable polymers blend was used such as poly-lactic acid (PLA) and poly-l-glycolic acid (PLGA) to study the shape memory effect of polymer. The prepared stent was assessed for various parameters like Scanning Electron Microscopy (SEM), In-vitro and Ex vivo expansion, Drug content, In-vitro drug release, Haemocompatibility, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared spectroscopy (FTIR), and Textural Characterization.

Endoscopic biodegradable biliary stents in the treatment of benign biliary strictures: First report of clinical use in patients

The first clinical experience of endoscopically inserted polydioxanone biodegradable biliary stents (BDBS) in the treatment of benign biliary strictures is reported. Two patients with a benign common bile duct stricture were endoscopically treated with 8-mm-bore BDBS during endoscopic retrograde cholangiography. Both BDBS insertions were technically successful and without adverse events. At 6 months, the stricture resolution was excellent and BDBS degradation was predicted in repeated magnetic resonance imaging. The first experience with endoscopic BDBS seems promising in the treatment of benign biliary strictures. During 6 months of follow up, BDBS seemed sufficient for remodeling and resolution of strictures. Further studies are needed to confirm the effectiveness of biodegradable biliary stents in endoscopic management of benign biliary strictures.

Bench and initial preclinical results of a novel 8 mm diameter double opposed helical biodegradable stent

BACKGROUND

Metallic endovascular stents are utilized off-label in congenital heart disease. Biodegradable stents (BDS) offer potential advantages in a growing child. We have previously reported double opposed helical (DH) BDS up to 6 mm diameter (DH-6). The objectives are to investigate the bench characteristics of larger 8 mm diameter BDS (DH-8) manufactured with increasing strut thicknesses and the inflammatory profile in a porcine model.

METHODS

DH-8 were manufactured with strut thicknesses 0.10, 0.12, and 0.18 mm and mechanical testing performed. Stents were deployed into the infrarenal descending aorta (DAO) of nine minipigs. At insertion (nonsurvival = 2), 1 week (n = 2), 1 month (n = 2), and 9 months (n = 3) follow-up angiography, intravascular ultrasound and histopathology were performed.

RESULTS

There was superior recoil and collapse pressure with increasing strut thickness, with 0.18 mm having 1.0% elastic recoil and collapse pressure 0.75 Atmospheres. There was good wall apposition at insertion with 5 BDS (4 DH-8 and 1 DH-6) but suboptimal in 4 as the minipigs infrarenal DAO were >8 mm (deployed at iliac bifurcation). Structural integrity was maintained in 8 BDS with 1 DH-8 collapsed at 9 months, secondary to strut damage at insertion. No thrombosis was seen. There was mild inflammation and neointimal proliferation at 1 week and 1 month, but a moderate inflammatory response at 9 months.

CONCLUSIONS

DH-8 with increased strut thickness had acceptable mechanical properties at the cost of an increased inflammatory response. Miniaturization to improve delivery and further investigation on the long-term inflammatory profile of thicker struts, including through degradation, is needed. © 2016 Wiley Periodicals, Inc.

Biodegradable biliary stents have a different effect than covered metal stents on the expression of proteins associated with tissue healing in benign biliary strictures

BACKGROUND

Benign biliary strictures (BBS) are primarily treated endoscopically with covered self-expandable metal stents (CSEMS). Biodegradable biliary stents (BDBS) may be the future of endoscopic therapy of BBS. The aim was to assess the expression of proteins related to tissue healing in BBS compared with the intact bile duct (BD), and to study the protein expression after therapy with CSEMS or BDBS.

METHODS

Pigs with ischemic BBS were endoscopically treated either with BDBS or CSEMS. Samples were harvested from pigs with intact BD (n = 5), untreated BBS (n = 5), and after six months of therapy with BDBS (n = 4) or CSEMS (n = 5) with subsequent histologic analysis. Two-dimensional electrophoresis with protein identification was performed to evaluate protein expression patterns.

RESULTS

In BBS, the expression of galectin-2 and annexin-A4 decreased, compared to intact BD. Treatment with biodegradable stents normalized galectin-2 level; with CSEMS therapy it remained low. Transgelin expression of intact BD and BBS remained low after BDBS treatment but increased after CSEMS therapy. Histologic analysis did not show unwanted foreign body reaction or hyperplasia in the BD in either group.

CONCLUSIONS

The expression of proteins related to tissue healing in BBS is different after treatment with biodegradable stents and CSEMS. Treatment with biodegradable stents may bring protein expression towards what is seen in intact BD. BDBS seem to have a good biocompatibility.

Mason type 3 radial head fractures: proposal of a synthesis technique using bioabsorbable thread

Multifragmentary fractures of the radial head (Mason type 3) are challenging for the surgeon. They are usually treated by means of complete removal of the injured head and sometimes by implantation of a metal prosthesis. Indeed, the bone fragments are often too small to allow stabilization through screws or even wires. The Author proposes an alternative technique, tested on a sawbone model, in which bioabsorbable thread is used, introduced in a figure-of-eight fashion. A review of the literature is provided.

RESOLVE: bioabsorbable steroid-eluting sinus implants for in-office treatment of recurrent sinonasal polyposis after sinus surgery: 6-month outcomes from a randomized, controlled, blinded study

BACKGROUND

Patients with recurrent sinonasal polyposis after endoscopic sinus surgery (ESS) have limited treatment options. Safety and efficacy were previously reported for a bioabsorbable sinus implant that elutes mometasone furoate for 3 months. Here we summarize longer-term outcomes.

METHODS

A randomized, controlled, blinded study with 100 chronic rhinosinusitis with nasal polyps (CRSwNP) patients who failed medical treatment and were considered candidates for revision ESS. Treated patients (n = 57) underwent in-office implant placement. Control patients (n = 43) underwent a sham procedure. Endoscopic grading at 3 months by clinicians was corroborated by an independent review of randomized videoendoscopies by a panel of 3 sinus surgeons. Six-month follow-up included endoscopic grading and patient-reported outcomes.

RESULTS

At 6 months, treated patients experienced significant improvement in Nasal Obstruction Symptom Evaluation (NOSE) score (p = 0.021) and >2-fold improvement in mean nasal obstruction/congestion score (-1.06 ± 1.4 vs -0.44 ± 1.4; p = 0.124). Endoscopically, treated patients experienced significant reduction in ethmoid sinus obstruction (p < 0.001) and bilateral polyp grade (p = 0.018) compared to controls. Panel review confirmed a significant reduction in ethmoid sinus obstruction (p = 0.010) and 2-fold improvement in bilateral polyp grade (p = 0.099), which reached statistical significance (p = 0.049) in a subset of 67 patients with baseline polyp burden ≥2 bilaterally. At 6 months, control patients were at 3.6 times higher risk of remaining indicated for ESS than treated patients.

CONCLUSION

The symptomatic and endoscopic improvements observed confirm the efficacy of the steroid-eluting implant for in-office treatment of CRSwNP after ESS. These longer-term 6-month study results demonstrate that the steroid-eluting implant represents a durable, safe, and effective treatment strategy for this patient population.

Unfavourable short-term outcomes of a poly-L/D-lactide scaffold for thumb trapeziometacarpal arthroplasty

The bioabsorbable poly-L-D-lactide joint scaffold arthroplasty is a recent attempt in the reconstruction of small joints in rheumatoid patients. In this study, we analysed the 1-year clinical, functional and radiologic results of partial trapeziectomy with the poly-L-D-lactide (96/4) joint scaffold in 23 patients with isolated trapeziometacarpal osteoarthritis. The results showed that the procedure provided pain relief and improvement in overall function according to the Quick Disabilities of the Arm, Shoulder and Hand score in most patients. However, radiographs demonstrated a high frequency of osteolysis around the implant. Seven patients developed clinically manifested foreign-body reactions 6 months to 1 year after surgery. The reason for the unexpected tissue reactions may relate to excessive mechanical cyclic loading of the implant. The outcomes of this implant in our patients have not been sufficiently beneficial and we have discontinued use of this implant in isolated trapeziometacarpal osteoarthritis.

Delayed absorbable synthetic plug (GORE® BIO-A®) for the treatment of fistula-in-ano: a systematic review

AIM

Recent advances in the treatment of fistula-in-ano have focused on surgical techniques that preserve sphincter integrity. Plugs that obliterate the lumen of the fistula track have been proposed as one such method, and may be derived from biological or delayed absorbable synthetic materials. Biological plugs have highly variable results and have not been widely adopted. The aim of this systematic review was to assess the effectiveness and safety of a delayed absorbable synthetic plug (GORE® BIO-A®) for treatment of anal fistula.

METHOD

A systematic review of all literature in the English language relevant to the use of a plug to treat anal fistula and published between 1 January 2008 and 15 February 2015 was carried out by searching MEDLINE, EMBASE and the Cochrane Library of Systematic Reviews/Controlled Trials for relevant literature. Relevant articles were identified, quality assessed using the methodological index for nonrandomized studies criteria and data were extracted by two independent researchers (SKN and NNA). The identified articles were assessed with regard to fistula healing rate, duration of follow-up and complication rates related to the use of delayed absorbable synthetic fistula plugs.

RESULTS

Twenty six potential articles were identified from the literature search. Using the predefined inclusion and exclusion criteria, six were included in the final analysis, data extraction and data synthesis. Of these included in the review only three were prospective in design. Complete data were available for 187 of the 221 patients who underwent this treatment. The age of the participants ranged from 19 to 82 years. The fistula healing rates were reported to be between 15.8% and 72.7% at a follow-up ranging between 2 and 19 months. Early or delayed plug extrusion occurred in 16 (8.5%) of the 187 patients. Deterioration in continence was reported in 11 (5.8%) of 187 patients.

CONCLUSION

There are insufficient high-quality data on the delayed absorbable synthetic (GORE® BIO-A®) fistula plug to draw meaningful conclusions regarding its effectiveness. It does, however, appear to be a simple and safe technique associated with low complication rates and a minor deterioration in continence in a few cases.

Bioabsorbable Versus Titanium Screws in Anterior Cruciate Ligament Reconstruction Using Hamstring Autograft: A Prospective, Blinded, Randomized Controlled Trial With 5-Year Follow-up

BACKGROUND

Longer-term results of bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been reported, but results are specific to the exact screw material and design. Titanium and poly-L-lactic acid with hydroxyapatite (PLLA-HA) screw outcomes have been compared only to 2 years.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the clinical and radiologic outcomes of the PLLA-HA screw versus titanium screw for hamstring tendon ACLR over a 5-year follow-up period. The hypothesis was that there are no differences in clinical scores or tunnel widening between the PLLA-HA and the titanium screws and that the PLLA-HA screw as seen on magnetic resonance imaging (MRI) should show high-grade resorption and ossification response over 5 years.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 40 patients undergoing ACLR were randomized to receive either a PLLA-HA screw (PLLA-HA group) or a titanium screw (titanium group) for ACL fixation. Blinded evaluation was performed at 2 and 5 years with the International Knee Documentation Committee and Lysholm knee score, KT-1000 arthrometer, single-legged hop test, and MRI to evaluate tunnel and screw volumes, periscrew ossification, graft integration, and cyst formation.

RESULTS

There was no difference in any clinical outcome measure at 2- or 5-year follow-up between the 2 groups. At 2 years, the femoral tunnel in the PLLA-HA group was smaller than that in the titanium group (P = .02); at 5 years, there was no difference. At 2 years, the femoral PLLA-HA screw was a mean 76% of its original volume, and by 5 years, it was 36%. At 2 years, the tibial PLLA-HA screw mean volume was 68% of its original volume, and by 5 years, it was 46%. At 5 years in the PLLA-HA group, 88% of femoral tunnels and 56% of tibial tunnels demonstrated a significant ossification response. There was no increase in cyst formation in the PLLA-HA group and no screw breakages.

CONCLUSION

There were equivalent clinical results between the PLLA-HA and titanium groups at 2- and 5-year follow-ups. The PLLA-HA screw was not associated with increased tunnel widening or cyst formation when compared with the titanium screw. The PLLA-HA screw demonstrated progressive screw resorption and gradual but incomplete ossification over 5 years.

Safety and efficacy of bioabsorbable cervical spacers and low-dose rhBMP-2 in multi-level ACDF

Introduction

Many options for interbody spacer and graft biologic exist for multilevel anterior cervical discectomy and fusion (ACDF). The objective of this study is to evaluate the safety and efficacy of a bioabsorbable cervical spacer (BCS) (Cornerstone HSR, Medtronic Sofamor Danek) filled with low-dose rhBMP-2 (INFUSE, Medtronic Sofamor Danek) in multilevel ACDF.

Methods

72 consecutive patients treated with a multi-level ACDF using BCS and rhBMP-2 (dosage between 0.5 to 0.7 mg per level) at a single institution were followed in an IRB-approved, prospective registry. A total of 187 levels were treated (mean = 2.6), with 37 (51%) patients undergoing a 2-level procedure and 35 (49%) undergoing a 3- or 4-level procedure. Statistical analysis included frequency and ANOVA tests. Significance was accepted for p < 0.001.

Results

Average follow-up was 13.8 months. Mean patient age was 55.3 years, 70.8% were female, and 16.7% had undergone a previous cervical procedure. 29 (40%) patients had cervical spondylitic myelopathy, 27 (38%) had radiculopathy, 15 (21%) had a combination of both, and 1 (1%) patient had a previous nonunion.

A total of 187 levels were treated with an ACDF, with 37 (51%) 2-level, 27 (38%) 3-level, and 8 (11%) 4-level cases. Average OR time, EBL, and LOS were 144 minutes, 49 mL, and 1.1 days, respectively. Major complications occurred in 5 (7%) patients: 2 returns to OR (1 nonunion, 1 seroma), 1 recurrent laryngeal nerve injury, and 2 hospital readmissions for excessive pre-vertebral swelling/dysphagia treated with steroids and observation. Minor complications occurred in 3 (4%) patients: 2 exacerbations of pre-existing medical conditions (1 atrial fibrillation, 1 COPD), and 1 hospital readmission for nausea/ headache due to narcotics.

At last follow-up, NDI improved 43% from 43.6% to 25.0%. VAS neck pain improved 60% from 5.5 to 2.2 and VAS arm pain improved 52% from 5.8 to 2.6. SF-36 PCS improved 24% from 37.5 to 46.3 and MCS improved 18% from 43.2 to 50.9. All clinical improvements were statistically significant (p < 0.001).

Patient satisfaction was high, with 97% of patients reported being satisfied with their surgical outcome, and 90% would undergo the procedure again.

Conclusion

Patients in this series experienced significant clinical improvements, low complication rates, and high patient satisfaction. Symptomatic pseudoarthrosis was rare. BCS filled with low-dose rhBMP-2 appears to be a safe and effective option in multilevel ACDF. Further investigation is warranted.

Long-term successful arthroscopic repair of large and massive rotator cuff tears with a functional and degradable reinforcement device

BACKGROUND

Rotator cuff repair is a procedure with varying outcomes, and there has been subsequent interest in devices that reinforce the repair and enhance structural and functional outcomes. The objective of this study was to determine these outcomes for arthroscopic repair of large and massive rotator cuff tears augmented with a synthetic absorbable mesh designed specifically for reinforcement of tendon repair by imaging and clinical assessments.

MATERIALS AND METHODS

Consecutive arthroscopic repairs were performed on 18 patients with large to massive rotator cuff tears by use of a poly-l-lactic acid synthetic patch as a reinforcement device and fixation with 4 sutures. Patients were assessed preoperatively and at 6 months, 12 months, and a mean of 42 months after surgery by the American Shoulder and Elbow Surgeons (ASES) shoulder score to evaluate clinical performance and at 12 months by ultrasound to assess structural repair.

RESULTS

Ultrasound showed that 15 of 18 patients had intact rotator cuff repair at 12 months; at 42 months, an additional patient had a failed repair. Patients showed improvement in the ASES shoulder score from 25 preoperatively to 71 at 12 months and 70 at 42 months after surgery. Patients with intact rotator cuff (n = 14) at 42 months had an ASES shoulder score of 82.

DISCUSSION

The poly-l-lactic acid bioabsorbable patch designed specifically to reinforce the surgical repair of tendons supported successful repair of large to massive rotator cuff tears in 83% of patients at 12 months after surgery and 78% of patients at 42 months after surgery, with substantial functional improvement.

Steroid-eluting sinus implant for in-office treatment of recurrent polyposis: a pharmacokinetic study

BACKGROUND

Long-term use of systemic glucocorticoid therapy has been associated with hypothalamic-pituitary-adrenal axis suppression and other systemic adverse events. This pharmacokinetic study evaluated the systemic safety and performance of a bioabsorbable sinus implant that gradually releases 1350 μg of mometasone furoate directly to the sinus mucosa.

METHODS

A prospective, single-center study treating 5 adult patients with recurrent polyposis after bilateral total ethmoidectomy. Each patient received 2 steroid-releasing implants in-office under local/topical anesthesia. Plasma concentrations of mometasone furoate and cortisol were determined before placement and through 30-day follow-up, which also included endoscopic grading and patient-reported outcomes.

RESULTS

Five patients (mean age 46.2 ± 9.2 standard deviation [SD] years; 60% male) underwent successful placement in all 10 ethmoid sinuses. There were no serious adverse events. The plasma concentrations of mometasone furoate were generally below the lower limit of quantification (LLOQ) of the assay (30 pg/mL). Cortisol concentrations at follow-up ranged from 3.9 to 5.7 mg/dL compared to 4.7 mg/dL at baseline. At 1 month, there was a significant improvement in bilateral polyp grade (p = 0.037), nasal obstruction score (p = 0.002), and 22-item Sino-Nasal Outcome Test (SNOT-22) (p = 0.010) compared to baseline.

CONCLUSION

The reported 100% placement success, negligible systemic exposure to mometasone furoate released over time, lack of adrenal suppression, and the absence of serious adverse events suggest that the implant provides a valid and safe option for the in-office treatment of recurrent polyposis. Randomized, controlled, blinded clinical studies are underway to provide further evidence of safety and efficacy.

Salvage of side branch by provisional "TAP technique" using Absorb™ bioresorbable vascular scaffolds for bifurcation lesions: first case reports with technical considerations

Recent technological developments have led to the development of Absorb™ bioresorbable vascular scaffold (BVS) [Abbott Vascular, Santa Clara, USA] for percutaneous treatment of coronary artery disease by percutaneous coronary intervention (PCI). The BVS is now approved for use in many countries but experience in bifurcation lesions is limited and largely unreported and concerns still exist about its use across major side branches. We report for the first time, the successful use of the "T and Protrusion" (TAP) technique of deploying BVS into the side branch (SB) through the struts of main branch (MB) BVS to salvage a suboptimal result and threatened closure of a SB in three cases when treating bifurcation lesions with a planned single BVS strategy. The TAP technique was successful in all cases and there were no complications. All patients continue to do well at short-term follow-up. This case report provides information regarding the feasibility as well as technical and procedural insights when using BVS for bifurcation lesions.

Steroid-eluting sinus implant for in-office treatment of recurrent nasal polyposis: a prospective, multicenter study

BACKGROUND

Treatment options for chronic rhinosinusitis with recurrent polyposis (CRSwNP) after endoscopic sinus surgery (ESS) are limited, and include frequent use of systemic steroids and revision surgery. A bioabsorbable, steroid-eluting implant was studied for its ability to dilate sinuses obstructed by polyps and provide localized, controlled steroid delivery to reestablish sinus patency. This study assessed the initial feasibility, safety, and efficacy of steroid-eluting implants placed in the office setting in patients who were candidates for revision ESS.

METHODS

Prospective, multicenter study enrolling 12 patients who had prior ESS but experienced recurrent polyposis refractory to medical therapy. Implants were placed bilaterally under topical anesthesia in-office. Follow-up through 6 months included endoscopic grading, patient-reported outcomes (22-item Sino-Nasal Outcomes Test [SNOT-22]) and need for revision ESS.

RESULTS

Implants were successfully inserted in 21 of 24 (88%) ethmoid sinuses, resulting in 11 evaluable patients. No serious adverse events occurred. Within 1 month, mean bilateral polyp grade was reduced from 4.5 at baseline to 2.3 (p = 0.008) and sustained through 6 months (2.33; p = 0.008). Mean SNOT-22 score was significantly improved from 2.19 at baseline to 0.90 within 1 month (p = 0.001) and sustained to 6 months (1.03; p = 0.012). Sixty-four percent of patients were no longer revision ESS candidates at 6 months.

CONCLUSION

The study provided initial clinical evidence of the feasibility, safety, and efficacy of in-office steroid-eluting implant placement in CRS patients with recurrent polyposis after ESS. Although further studies are needed, the results suggest this therapy may provide a safe and effective, office-based option for the treatment of obstructive polyposis.

Novel anterior cruciate ligament graft fixation device reduces slippage

Clinically significant laxity occurs in 10%–30% of knees after anterior cruciate ligament reconstruction. Graft slippage and tension loss at the hamstring graft tibial fixation site during and after reconstruction surgery contribute to postoperative joint laxity and are detrimental to long-term knee stability and graft properties. Limiting graft slippage will reduce associated complications. We sought to compare the in vitro mechanical properties and in vivo joint stabilization, postoperative limb use, and graft incorporation of the novel GraftGrab™ (GG) device designed to reduce hamstring graft tibial fixation slippage with the commercially available bioabsorbable Bio-Post™ and spiked washer (BP). Mechanical testing was performed on canine tibia-hamstring graft constructs to quantify initial fixation properties. In vivo joint stabilization, postoperative limb use and graft incorporation of hamstring graft reconstructions were determined in a canine model. Outcomes included tibial translation and ground reaction forces preoperatively and 4 and 8 weeks postoperatively, three-dimensional graft and bone tunnel dimensions at the latter two time points, and graft-bone microstructure, as well as mechanical properties 8 weeks after implantation. Immediately after fixation, all grafts slipped from the BP constructs versus about 30% of GG constructs. In vivo limb use remained low, and tibial translation increased with time in the BP cohort. These results together confirm that initial graft slippage is lower with GG versus BP extracortical hamstring graft tibial fixation. In addition, postoperative recovery and joint stability are more consistent with the GG. This information supports the GG as an alternative to extracortical tibial hamstring graft fixation that has procedural advantages over current implants and reduces graft failure from slippage.

Osteogenic scaffolds for bone reconstruction

A highly osteogenic hybrid bioabsorbable scaffold was developed for bone reconstruction/augmentation. Through the use of a solid free-form fabrication technology, a bioabsorbable polycaprolactone (PCL) cage scaffold with a desired size and shape was produced and then filled with osteogenic bone graft particles, that is, morselized autologous bone chips. A rabbit total lamina defect model was chosen to demonstrate its efficacy in regenerating bone with a complicated anatomic shape. Both iliac bone and morselized iliac bone grafts were used in this study for comparison purposes. Serum osteocalcin and collagen type I cross-linked C-terminal telopeptide (CTx) determination showed that active bone remodeling occurred after bone grafts were implanted. X-ray images showed that the bony defects were completely filled with bone mass in all the groups with bone grafts. However, biomechanical tests showed that only the iliac bone and hybrid scaffold groups could restore the mechanical properties to the normal level after 10 weeks of implantation. A histology study showed that both iliac and hybrid scaffold groups had extensive new bone formation, and no adhesion and fibrosis were found. These results indicated that this osteogenic hybrid scaffold can be a good alternative to autologous iliac bone, because it does not need a second iliac bone-harvesting surgery, and thus the morbidity and the possible infections that are often associated with the bone harvesting surgery can be avoided.

Biomechanical stability of a bioabsorbable self-retaining polylactic acid/nano-sized β-tricalcium phosphate cervical spine interbody fusion device in single-level anterior cervical discectomy and fusion sheep models

Purpose

The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, β-tricalcium phosphate, bioabsorbable, self-retaining cervical fusion cage (BCFC).

Methods

Quasistatic nonconstraining torques (maximum 1.5 NM) induced flexion, extension, lateral bending (±1.5 NM), and axial rotation (±1.5 NM) on 32 sheep cervical spines (C2–C5). The motion segment C3–C4 was first tested intact; the following groups were tested after complete discectomy: autologous tricortical iliac crest bone graft, Medtronic–Wego polyetheretherketone (PEEK) cage, Solis PEEK cage, and BCFC. The autologous bone graft group was tested with an anterior plate. The mean range of motion (ROM) was calculated from the load-displacement curves.

Results

BCFC significantly decreased ROM in lateral bending and axial rotation compared to other implants, and no significant difference in ROM between two types of PEEK cages and BCFC could be observed in flexion and extension. Anterior cervical plate (ACP) significantly decreased ROM in flexion and extension, but no significant difference in ROM between BCFC and bone graft plus ACP could be determined in lateral bending and axial rotation.

Conclusion

The BCFC device showed better stability to autologous tricortical iliac crest bone graft and PEEK cages in single-level anterior cervical discectomy and fusion models and thus may be a potential alternative to the current PEEK cages.

Comparative evaluation of a bioabsorbable collagen membrane and connective tissue graft in the treatment of localized gingival recession: A clinical study

Background:

Gingival recession (GR) can result in root sensitivity, esthetic concern to the patient, and predilection to root caries. The purpose of this randomized clinical study was to evaluate (1) the effect of guided tissue regeneration (GTR) procedure using a bioabsorbable collagen membrane, in comparison to autogenous subepithelial connective tissue graft (SCTG) for root coverage in localized gingival recession defects; and (2) the change in width of keratinized gingiva following these two procedures.

Materials and Methods:

A total of 10 cases, showing at least two localized Miller's Class I or Class II gingival recession, participated in this study. In a split mouth design, the pairs of defects were randomly assigned for treatment with either SCTG (SCTG Group) or GTR-based collagen membrane (GTRC Group). Both the grafts were covered with coronally advanced flap. Recession depth (RD), recession width (RW), width of keratinized gingiva (KG), probing depth (PD), relative attachment level (RAL), plaque index (PI), and gingival index (GI) were recorded at baseline, 3 and 6 months postoperatively.

Results:

Six months following root coverage procedures, the mean root coverage was found to be 84.84% ± 16.81% and 84.0% ± 15.19% in SCTG Group and GTRC Group, respectively. The mean keratinized gingival width increase was 1.50 ± 0.70 mm and 2.30 ± 0.67 mm in the SCTG and GTRC group, respectively, which was not statistically significant.

Conclusion:

It may be concluded that resorbable collagen membrane can be a reliable alternative to autogenous connective tissue graft in the treatment of gingival recession.