A Novel Biodegradable Polycaprolactone Fixator for Osteosynthesis Surgery of Rib Fracture: In Vitro and in Vivo Study

Development of novel hybrid 3D-printed degradable artificial joints incorporating electrospun pharmaceutical- and growth factor-loaded nanofibers for small joint reconstruction

Small joint reconstruction remains challenging and can lead to prosthesis-related complications, mainly due to the suboptimal performance of the silicone materials used and adverse host reactions. In this study, we developed hybrid artificial joints using three-dimensional printing (3D printing) for polycaprolactone (PCL) and incorporated electrospun nanofibers loaded with drugs and biomolecules for small joint reconstruction. We evaluated the mechanical properties of the degradable joints and the drug discharge patterns of the nanofibers. Empirical data revealed that the 3D-printed PCL joints exhibited good mechanical and fatigue properties. The drug-eluting nanofibers sustainedly released teicoplanin, ceftazidime, and ketorolac in vitro for over 30, 19, and 30 days, respectively. Furthermore, the nanofibers released high levels of bone morphogenetic protein-2 and connective tissue growth factors for over 30 days. An in vivo animal test demonstrated that nanofiber-loaded joints released high concentrations of antibiotics and analgesics in a rabbit model for 28 days. The animals in the drug-loaded degradable joint group showed greater activity counts than those in the surgery-only group. The experimental data suggest that degradable joints with sustained release of drugs and biomolecules may be utilized in small joint arthroplasty.

Advances in additive manufacturing of polycaprolactone based scaffolds for bone regeneration

Critical sized bone defects are difficult to manage and currently available clinical/surgical strategies for treatment are not completely successful. Polycaprolactone (PCL) which is a biodegradable and biocompatible thermoplastic can be 3D printed using medical images into patient specific bone implants. The excellent mechanical properties and low immunogenicity of PCL makes it an ideal biomaterial candidate for 3D printing of bone implants. Though PCL suffers from the limitation of being bio-inert. Here we describe the use of PCL as a biomaterial for 3D printing for bone regeneration, and advances made in the field. The specific focus is on the different 3D printing techniques used for this purpose and various modification that can enhance bone regeneration following the development pathways. We further describe the effect of various scaffold characteristics on bone regeneration both in vitro and the translational assessment of these 3D printed PCL scaffolds in animal studies. The generated knowledge will help understand cell-material interactions of 3D printed PCL scaffolds, to further improve scaffold chemistry and design that can replicate bone developmental processes and can be translated clinically.

Biodegradable Antimicrobial Agent/Analgesic/Bone Morphogenetic Protein-Loaded Nanofibrous Fixators for Bone Fracture Repair

Purpose

Postoperative infection and pain management are of great concern to orthopedic surgeons. Although there are several protocols available to deal with these aspects, they are fraught with complications, such as cartilage damage, cardiovascular and neurological intoxication, and systemic adverse responses. Therefore, it is necessary to develop safe and effective perioperative protocols. In the current study, antimicrobial agents/analgesics/growth factor-embedded biodegradable hybrid fixators (polycaprolactone fixator + poly[lactide-co-glycolide] sheath-core structured nanofibers) for bone fracture repair were designed.

Methods

The biodegradable hybrid fixators were fabricated using solution-extrusion three-dimensional printing and electrospinning. In vitro, the characteristics of the hybrid fixators were examined. Additionally, the release of the incorporated vancomycin, ceftazidime, lidocaine, and bone morphogenetic protein-2 (BMP-2) was evaluated. The in vivo efficacy including drug-eluting properties, fracture repair, and pain management of the biomolecule-loaded nanofibrous fixators was investigated in rabbit rib-fracture models.

Results

The nanofibrous fixators released vancomycin, ceftazidime, and lidocaine in a sustained manner under both in vitro and in vivo conditions and protected BMP-2 from burst release. The implantation of these hybrid fixators around the fractured rib significantly improved animal activities and bone union, indicating that the inclusion of analgesic in the fixator effectively reduced postsurgical pain and thereby helped in recovery.

Conclusion

The novel biomolecule-loaded nanofibrous hybrid fixators resulted in excellent therapeutic outcomes. These fixators may be effective in the repair of rib fractures in clinical settings and may help mitigate surgical complications, such as infection, nonunion, and intolerable postoperative pain.

A new instrument for surgical stabilization of multiple rib fractures

Objective

Rib fixation is an effective treatment for patients with multiple rib fractures. We retrospectively evaluated the application of a four-claw titanium plate in patients with rib fractures.

Methods

Fifty-four patients treated for multiple rib fractures in our hospital from 2012 to 2016 were divided into a surgery group (n = 27) and conservative treatment group (n = 27). The patients’ age, sex, cause of fracture, Injury Severity Score, chest Abbreviated Injury Scale score, number of ventilator days, and length of hospitalization were recorded.

Results

The mean duration of mechanical ventilation was 4.5 ± 0.7 and 7.9 ± 1.7 days in the surgery and control group, respectively, with a significant difference. The length of intensive care unit stay was also significantly different between the groups (5.9 ± 0.6 vs. 10.6 ± 1.9 days, respectively). The length of hospital stay and recovery time to regular life in the surgery and control group were 11.5 ± 1.9 and 3.9 ± 4.0 days and 38.2 ± 8.3 and 60.8 ± 12.1 days, respectively, both with significant differences.

Conclusion

A four-claw titanium plate is valuable for patients with multiple rib fractures, allowing easy fixation of broken ribs beneath the scapula, even the second rib.

Electrochemical methods for fabrication of polymers/calcium phosphates nanocomposites as hard tissue implants

Developing and manipulating new biomaterials is an ongoing topic for their needs in medical uses. The evolution and development of new biomaterials, in both the academic and industrial sectors, have been encouraged due to the dramatic improvement in medicine and medical-related technologies. Due to the drawbacks associated with natural biomaterials, the use of synthetic biomaterials is preferential due to basic and applied aspects. Various techniques are involved in fabricating biomaterials. Among them are the electrochemical-based methods, which include electrodeposition and electrophoretic methods. Although electrospinning and electrospraying are not typical electrochemical methods, they are also reviewed in this article due to their importance. Many remarkable features can be acquired from this technique. Electrodeposition and electrophoretic deposition are exceptional and valuable processes for fabricating thin or thick coated films on a surface of metallic implants. Electrodeposition and electrophoretic deposition have some common positive features. They can be used at low temperatures, do not affect the structure of the implant, and can be applied to complex shapes, and they can produce superior properties, such as quick and uniform coating. Furthermore, they can possibly control the thickness and chemical composition of the coatings. Electrospinning is a potentially emerging and efficient process for producing materials with nanofibrous structures, which have exceptional characteristics such as mechanical properties, pore size, and superior surface area. These specialized characteristics induce these nanostructured materials to be used in different technologies.

Novel electrospun poly(ε-caprolactone)/type I collagen nanofiber conduits for repair of peripheral nerve injury

Recent studies have shown the potential of artificially synthesized conduits in the repair of peripheral nerve injury. Natural biopolymers have received much attention because of their biocompatibility. To investigate the effects of novel electrospun absorbable poly(ε-caprolactone)/type I collagen nanofiber conduits (biopolymer nanofiber conduits) on the repair of peripheral nerve injury, we bridged 10-mm-long sciatic nerve defects with electrospun absorbable biopolymer nanofiber conduits, poly(ε-caprolactone) or silicone conduits in Sprague-Dawley rats. Rat neurologica1 function was weekly evaluated using sciatic function index within 8 weeks after repair. Eight weeks after repair, sciatic nerve myelin sheaths and axon morphology were observed by osmium tetroxide staining, hematoxylin-eosin staining, and transmission electron microscopy. S-100 (Schwann cell marker) and CD4 (inflammatory marker) immunoreactivities in sciatic nerve were detected by immunohistochemistry. In rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits, no serious inflammatory reactions were observed in rat hind limbs, the morphology of myelin sheaths in the injured sciatic nerve was close to normal. CD4 immunoreactivity was obviously weaker in rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits than in those subjected to repair with poly(ε-caprolactone) or silicone. Rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits tended to have greater sciatic nerve function recovery than those receiving poly(ε-caprolactone) or silicone repair. These results suggest that electrospun absorbable poly(ε-caprolactone)/type I collagen nanofiber conduits have the potential of repairing sciatic nerve defects and exhibit good biocompatibility. All experimental procedures were approved by Institutional Animal Care and Use Committee of Taichung Veteran General Hospital, Taiwan, China (La-1031218) on October 2, 2014.

Development of a socket-type rib coaptation device made of poly-L-lactide fibers: feasibility study in a canine model

Background

Costal coaptation pins made of poly-L-lactide (PLA) are clinically available for fixing surgically divided ribs. However, the clinical results of such rib fixation have not been completely satisfactory. We aimed to develop a new rib coaptation socket system and explore its clinical applicability.

Methods

We surgically divided three consecutive ribs of each beagle dog, and rib coaptation sockets were implanted to stabilize each rib. Fifteen 3-dimensional (3D)-printed and 30 PLA fiber knitted sockets were implanted in five and ten dogs, respectively, to stabilize the artificially divided ribs. Mechanical analysis of the sockets and radiographical examination of costal fixation were performed to evaluate the effectiveness of the newly developed socket system for rib stabilization.

Results

All 15 ribs with 3D-printed sockets had displaced 1 month after the operation. Three ribs in one dog with implanted PLA fiber knitted sockets were displaced radiographically after 1 month, and the grade of displacement remained unchanged after 6 months. The remaining 27 ribs fixed with PLA fiber knitted sockets did not show any displacement.

Conclusions

The PLA fiber knitted rib coaptation socket system was sufficiently durable for the stabilization of divided ribs with biocompatibility. This promising finding can be applied for clinical stabilization of divided ribs.

Sustained relief of pain from osteosynthesis surgery of rib fracture by using biodegradable lidocaine-eluting nanofibrous membranes

Various effective methods are available for perioperative pain control in osteosynthesis surgery, but they are seldom applied intraoperatively. The aim of this study was to evaluate a biodegradable poly([d,l]-lactide-co-glycolide) (PLGA)/lidocaine nanofibrous membrane for perioperative pain control in rib fracture surgery. Scanning electron microscopy showed high porosity of the membrane, and an ex vivo high-performance liquid chromatography study revealed an excellent release profile for both burst and controlled release of lidocaine within 30days. Additionally, the PLGA/lidocaine nanofibrous membrane was applied in an experimental rabbit rib osteotomy model. Implantation of the membrane around the osteotomized rib during osteosynthesis surgery resulted in a significant increase in weight gain, food and water consumption, and daily activity compared to the study group without the membrane. In addition, all osteotomized ribs were united. Thus, application of the PLGA/lidocaine nanofibrous membrane may be effective for sustained relief of pain in oeteosynthesis surgery.