Biphasic calcium phosphate to repair nasal septum: the first in vitro and in vivo study

An overview of nasal cartilage bioprinting: from bench to bedside

Nasal cartilage diseases and injuries are known as significant challenges in reconstructive medicine, affecting a substantial number of individuals worldwide. In recent years, the advent of three-dimensional (3D) bioprinting has emerged as a promising approach for nasal cartilage reconstruction, offering potential breakthroughs in the field of regenerative medicine. This paper provides an overview of the methods and challenges associated with 3D bioprinting technologies in the procedure of reconstructing nasal cartilage tissue. The process of 3D bioprinting entails generating a digital 3D model using biomedical imaging techniques and computer-aided design to integrate both internal and external scaffold features. Then, bioinks which consist of biomaterials, cell types, and bioactive chemicals, are applied to facilitate the precise layer-by-layer bioprinting of tissue-engineered scaffolds. After undergoing in vitro and in vivo experiments, this process results in the development of the physiologically functional integrity of the tissue. The advantages of 3D bioprinting encompass the ability to customize scaffold design, enabling the precise incorporation of pore shape, size, and porosity, as well as the utilization of patient-specific cells to enhance compatibility. However, various challenges should be considered, including the optimization of biomaterials, ensuring adequate cell viability and differentiation, achieving seamless integration with the host tissue, and navigating regulatory attention. Although numerous studies have demonstrated the potential of 3D bioprinting in the rebuilding of such soft tissues, this paper covers various aspects of the bioprinted tissues to provide insights for the future development of repair techniques appropriate for clinical use.

Partial nasal bone reconstruction with acrylic bone cement: experimental study

Background

The aim of this study was to evaluate the effectiveness of acrylic bone cement in partial nasal bone reconstruction.

Methods

This study was conducted using nine New Zealand rabbits. The left nasal bones of the rabbits were included in the experimental group, and the right nasal bones were evaluated as the control group. The partial bone segments on the bilateral nasal bones were marked and removed symmetrically. A synthetic graft material made of acrylic bone cement was placed in experimental group, and the partial bone segment removed from the right side was placed in control group as an autograft. All rabbits were sacrificed at the end of the 28th day. Samples were taken from the grafts and from the surrounding soft tissues for histopathological examination. Acute inflammation, chronic inflammation, vascularization, fibrosis, foreign body reaction, bone proliferation, and the presence of empty lacunae were evaluated under a light microscope for both groups.

Results

Surrounding soft tissue on synthetic and autograft were the same in terms of chronic inflammation. There was no statistically significant difference for vascularization, fibrosis, and foreign body reaction. Synthetic graft and autograft were the same in terms of chronic inflammation, fibrosis, and bone proliferation. There was no statistically significant difference for vascularization, foreign body reaction, and presence of empty lacunae (p > 0.05).

Conclusion

This study showed no significant differences between the use of acrylic bone and the use of an autograft for partial nasal bone reconstruction in terms of graft or tissue healing. Acrylic bone cement may therefore serve as a good alternative for nasal bone reconstruction.

A TGF-loading hydrogel scaffold capable of promoting chondrogenic differentiation for repairing rabbit nasal septum cartilage defect

Hydrogel-based tissue engineering has been widely used to repair cartilage injury. However, whether this approach can be applied to treat nasal septum cartilage defects remains unclear. In this study, three gelatin methacrylate-based scaffolds loaded with transforming growth factor (TGF)-β1 (GelMA-T) were prepared, and their effects on repair of nasal septum cartilage defects were examined. In vitro, the GelMA-T scaffolds showed good biocompatibility and promoted the chondrogenic differentiation of bone mesenchymal stem cells. Among three scaffolds, the 10% GelMA-T scaffold promoted chondrogenic differentiation most effectively, which significantly improved the expression of chondrocyte-related genes, including Col II, Sox9, and ACAN. In vivo, 10% GelMA-T scaffolds and 10% GelMA-T scaffolds loaded with bone mesenchymal stem cells (BMSCs; 10% GelMA-T/BMSCs) were transplanted into a nasal septum cartilage defect site in a rabbit model. At 4, 12, and 24 weeks after surgery, the nasal septum cartilage defects exhibited more complete repair in rabbits treated with the 10% GelMA-T/BMSC scaffold as demonstrated by hematoxylin & eosin, safranine-O, and toluidine blue staining. We showed that GelMA-T/BMSCs can be applied in physiological and structural repair of defects in nasal septum cartilage, providing a potential strategy for repairing cartilage defects in the clinic.

Endoscopic measurement of nasal septum perforations

Background

Nasal septum perforations (NSP) have many uncomfortable symptoms for the patient and a highly negative impact on quality of life. NSPs are closed using patient-specific implants or surgery. Implants are created either under anesthesia using silicone impressions or using 3D models from CT data. Disadvantages for patient safety are the increased risk of morbidity or radiation exposure.

Materials and methods

In the context of otorhinolaryngologic surgery, we present a gentle approach to treating NSP with a new image-based, contactless, and radiation-free measurement method using a 3D endoscope. The method relies on image information only and makes use of real-time capable computer vision algorithms to compute 3D information. This endoscopic method can be repeated as often as desired in the clinical course and has already proven its accuracy and robustness for robotic-assisted surgery (RAS) and surgical microscopy. We expand our method for nasal surgery, as there are additional spatial and stereoperspective challenges.

Results

After measuring 3 relevant parameters (NSP extension: axial, coronal, and NSP circumference) of 6 patients and comparing the results of 2 stereoendoscopes with CT data, it was shown that the image-based measurements can achieve comparable accuracies to CT data. One patient could be only partially evaluated because the NSP was larger than the endoscopic field of view.

Conclusion

Based on the very good measurements, we outline a therapeutic procedure which should enable the production of patient-specific NSP implants based on endoscopic data only.

[Endoscopic measurement of nasal septum perforations. German version]

BACKGROUND

Nasal septum perforations (NSP) have many uncomfortable symptoms for the patient and a highly negative impact on quality of life. NSPs are closed using patient-specific implants or surgery. Implants are created either under anesthesia using silicone impressions or using 3D models from CT data. Disadvantages for patient safety are the increased risk of morbidity or radiation exposure.

MATERIALS AND METHODS

In the context of otorhinolaryngologic surgery, we present a gentle approach to treating NSP with a new image-based, contactless, and radiation-free measurement method using a 3D endoscope. The method relies on image information only and makes use of real-time capable computer vision algorithms to compute 3D information. This endoscopic method can be repeated as often as desired in the clinical course and has already proven its accuracy and robustness for robotic-assisted surgery (RAS) and surgical microscopy. We expand our method for nasal surgery, as there are additional spatial and stereoperspective challenges.

RESULTS

After measuring 3 relevant parameters (NSP extension: axial, coronal, and NSP circumference) of 6 patients and comparing the results of 2 stereoendoscopes with CT data, it was shown that the image-based measurements can achieve comparable accuracies to CT data. One patient could be only partially evaluated because the NSP was larger than the endoscopic field of view.

CONCLUSION

Based on the very good measurements, we outline a therapeutic procedure which should enable the production of patient-specific NSP implants based on endoscopic data only.

Multicenter Pilot Study to Assess a Biphasic Calcium Phosphate Implant for Functional and Aesthetic Septorhinoplasty

Importance: A validated biomaterial would have several medical advantages in septorhinoplasties requiring a large-volume graft such as avoiding donor site morbidity, making ambulatory surgery possible, and reducing surgical costs. Objective: To assess the safety and efficacy of a ceramic to treat saddle and crooked noses. The main endpoint was the biocompatibility of the implant. The secondary endpoint was its functional and aesthetic efficacy. Design, Setting, and Participants: The nasal septum (NASEPT) study is a pilot multicenter noncomparative prospective phase IIa clinical trial. The biomaterial tested was a biphasic calcium phosphate implant composed of 75% hydroxyapatite and 25% beta tri calcium phosphate. This versatile material can be used to replace septal skeleton when it is absent or nonusable. We included 25 patients with a multifractured osseous and cartilaginous framework after several traumas or surgeries. The implant placement technique was identical to an extracorporeal septoplasty through the external approach. Main Outcomes and Measures: The primary endpoint was the occurrence of expected adverse and severe adverse events. The secondary endpoints were clinical functional and aesthetic results and histological microscopic modifications. Results: Any extrusion, infection, pain, and epistaxis were observed. All implants were placed in a sagittal, straight, and solid position without extralobular depression. Comparisons between pre- and postoperative symptoms showed that nasal comfort (p < 10^-4) and quality of life (p < 10^-4) were dramatically improved in all patients. The nasolabial angle (p = 0.047) and the columellar projection (p = 0.024) were improved after surgery. Histological data showed little submucosal inflammation at 6 months with well-differentiated epithelium. The mean follow-up was 23 months: three patients underwent revision surgery for functional or aesthetic details and four implants were removed (16%) owing to a foreign body reaction between 17 and 74 months. Conclusion and Relevance: The NASEPT implant meets functional and aesthetic requirements in complex septorhinoplasties but its long-term biocompatibility needs to be improved. It could potentially avoid donor site morbidity.

ß-Tricalcium Phosphate Implants in the Surgical Treatment of Empty Nose Syndrome

The objective of this study was to assess the efficacy and morbidity of a β-tricalcium phosphate implant in the treatment of empty nose syndrome after turbinectomy. Only patients with a history of inferior turbinectomy and a complaint of permanent paradoxical nasal obstruction were included. β-Tricalcium phosphate ceramic implants were implanted under the mucoperiosteal plane of the lateral nasal wall to replace the head of the inferior turbinate. Symptoms and quality of life were assessed by 2 questionnaires: the Nasal Obstruction Symptom Evaluation and Rhinosinusitis Quality of Life. Fourteen patients were included. The mean follow-up was 19.4 ± 13.4 months. Scores for the Nasal Obstruction Symptom Evaluation and Rhinosinusitis Quality of Life (frequency, bothersomeness, and impact) significantly improved after surgery (respectively, 73.9 ± 21.8 to 34.6 ± 28.6, 44.6 ± 17.1 to 34.8 ± 20.3, 43.6 ± 22.4 to 70.7 ± 21.5, and 59.9 ± 21.1 to 27.2 ± 25.3; P < .05). The use of ß-tricalcium phosphate seems efficient to repair empty nose syndrome by endonasal microplasty and shows a low complication rate.

Biphasic, triphasic and multiphasic calcium orthophosphates

Biphasic, triphasic and multiphasic (polyphasic) calcium orthophosphates have been sought as biomaterials for reconstruction of bone defects in maxillofacial, dental and orthopedic applications. In general, this concept is determined by advantageous balances of more stable (frequently hydroxyapatite) and more resorbable (typically tricalcium orthophosphates) phases of calcium orthophosphates, while the optimum ratios depend on the particular applications. Therefore, all currently known biphasic, triphasic and multiphasic formulations of calcium orthophosphate bioceramics are sparingly soluble in water and, thus, after being implanted they are gradually resorbed inside the body, releasing calcium and orthophosphate ions into the biological medium and, hence, seeding new bone formation. The available formulations have already demonstrated proven biocompatibility, osteoconductivity, safety and predictability in vitro, in vivo, as well as in clinical models. More recently, in vitro and in vivo studies have shown that some of them might possess osteoinductive properties. Hence, in the field of tissue engineering biphasic, triphasic and multiphasic calcium orthophosphates represent promising biomaterials to construct various scaffolds capable of carrying and/or modulating the behavior of cells. Furthermore, such scaffolds are also suitable for drug delivery applications. This review summarizes the available information on biphasic, triphasic and multiphasic calcium orthophosphates, including their biomedical applications. New formulations are also proposed.

Assessment of biphasic calcium phosphate to repair nasal septum defects in sheep

BACKGROUND

Saddle nose and septal perforations are among the most surgically challenging situations in nasal reconstruction. They require a significant volume of autologous graft and a complex surgical procedure. The aim of this study was to evaluate the biocompatibility of the biphasic calcium phosphate implant in the nasal septum and its ability to replace septal skeleton with unilateral or bilateral exposure.

METHODS

Thirty sheep underwent anterior nasal septum perforation. Only 20 septa were repaired with the implant exposed to nasal content on bilateral (group 2) and unilateral (group 3) sides. After 45 days of spontaneous cicatrization, the surface of new airway mucosa covering implants and the amount of closure were evaluated macroscopically. Light microscopy, histomorphometry, immunohistochemistry, and transmission electron microscopy were performed to assess soft-tissue growth and differentiation. Statistical analysis was performed by means of the Mann-Whitney test.

RESULTS

The mean rate of mucoperichondrial flap recovery of the implant was 66 percent in group 2 and 82 percent in group 3, and was significantly different from that of the control group (p < 10(-4)). The mean amount of closure was 32 and 64 percent, respectively (p < 10(-3)). The thickness of the perichondrium was greater than the control on both sides (p < 10(-4)). Vascularized soft tissues and bone formation invaded pores of implants. No pathologic inflammation was observed in submucosa. Moderately differentiated and well differentiated newly formed epithelium were the most frequent types observed, with good correlation between immunostaining and morphologic features.

CONCLUSION

These data suggest a good biocompatibility of biphasic calcium phosphate and its ability to repair the nasal septum in sheep.

Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates

In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells.