Protective Topical Dual-Sided Nanofibrous Hemostatic Dressing Using Mussel and Silk Proteins with Multifunctionality of Hemostasis and Anti-Bacterial Infiltration.

Topical hemostatic agents are preferred for application to sensitive bleeding sites because of their immediate locoregional effects with less tissue damage. However, the majority of commercial hemostatic agents fail to provide stable tissue adhesion to bleeding wounds or act as physical barriers against contaminants. Hence, it has become necessary to investigate biologically favorable materials that can be applied and left within the body post-surgery. In this study, a dual-sided nanofibrous dressing for topical hemostasis is electrospun using a combination of two protein materials: bioengineered mussel adhesive protein (MAP) and silk fibroin (SF). The wound-adhesive inner layer is fabricated using dihydroxyphenylalanine (DOPA)-containing MAP, which promotes blood clotting by aggregation of hemocytes and activation of platelets. The anti-adhesive outer layer is composed of alcohol-treated hydrophobic SF, which has excellent spinnability and mechanical strength for fabrication. Because both proteins are fully biodegradable in vivo and biocompatible, the dressing would be suitable to be left in the body. Through in vivo evaluation using a rat liver damage model, significantly reduced clotting time and blood loss are confirmed, successfully demonstrating that the proposed dual-sided nanofibrous dressing has the right properties and characteristics as a topical hemostatic agent having dual functionality of hemostasis and physical protection.

Bone Regeneration with 3D-Printed Hybrid Bone Scaffolds in a Canine Radial Bone Defect Model.

BACKGROUND: The repair of large bone defects remains a significant challenge in clinical practice and requires bone grafts or substitute materials. In this study, we developed a unique hybrid bone scaffold comprising a three dimensional (3D)-printed metal plate for weight bearing and a biodegradable polymer tube serving as bone conduit. We assessed the long-term effect of the hybrid bone scaffold in repairing radial bone defects in a beagle model. METHODS: Bone defects were created surgically on the radial bone of three beagle dogs and individually-tailored scaffolds were used for reconstruction with or without injection of autologous bone and decellularized extracellular matrix (dECM). The repaired tissue was evaluated by X-ray, micro-computed tomography, and histological observation 6 months after surgery. The functional integrity of hybrid bone scaffold-mediated reconstructions was assessed by gait analysis. RESULTS: In vivo analysis showed that the hybrid bone scaffolds maintained the physical space and bone conductivity around the defect. New bone was formed adjacent to the scaffolds. Addition of autologous bone and dECM in the polymer tube improved healing by enhancing bone induction and osteoconduction. Furthermore, the beagles' gait appeared normal by 4 months. CONCLUSION: The future of bone healing and regeneration is closely related to advances in tissue engineering. Bone production using autologous bone and dECM loaded on 3D-printed hybrid bone scaffolds can successfully induce osteogenesis and provide mechanical force for functional bone regeneration, even in large bone defects.

Two-team-approached free flap reconstruction for plantar malignant melanoma: An observational (STROBE-compliant) trial.

Reconstructive treatments of heel defects usually involve regional flap techniques such as medial plantar flap procedures due to the limited availability of adjacent soft tissues. Although free flaps have advantages in terms of function and aesthetics, they remain challenging due to the longer operation time required than for regional flaps. Thus, we introduce an appropriate 2-team surgical protocol to reconstruct plantar defects after wide excision of malignant melanoma using free flap coverage. From 2015 to 2020, a retrospective study was performed including 21 patients who underwent free flap surgeries to reconstruct defects due to plantar malignant melanoma. Lymphoscintigraphy was performed to localize sentinel lymph nodes, and the procedure was carried out by 2 teams working together, a tumor-ablative team and a reconstructive team. The present study is adhered to the STROBE guidelines for cohort studies. The average operation time was 241.4 minutes and was not significantly different even in cases with inguinal dissection (P value: 0.641). All flaps survived after 2 cases of venous insufficiency and 1 case of hematoma were resolved by immediate revision surgery. The 2-team approach to surgically reconstruct heel defects after wide excision of malignant melanoma using free flap coverage offers favorable results and lower morbidity than regional flap approaches.

Quantitative Assessment of the Restoration of Original Anatomy after 3D Virtual Reduction of Long Bone Fractures.

Background: The purpose of this study was to demonstrate the usefulness of 3D image-based virtual reduction by validating the evaluation criteria according to guidelines suggested by the AO Surgery Reference. Methods: For this experiment, 19 intact radial ORTHObones (ORTHObones radius, 3B Scientific, Germany, Hamburg) without any fractures were prepared. All ORTHObones with six cortical marking holes (three points on the distal part and three points on the proximal part) were scanned using a CT scanner twice (before/after intentional fracture of the ORTHObone). After the virtual reduction of all 19 ORTHObones, accuracy evaluations using the four criteria (length variation, apposition variation, alignment variation, Rotation Variation) suggested in the AO Surgery Reference were performed. Results: The mean (M) length variation was 0.42 mm, with 0.01 mm standard deviation (SD). The M apposition variation was 0.48 mm, with 0.40 mm SD. The M AP angulation variation (for alignment variation) was 3.24°, with 2.95° SD. The M lateral angulation variation (for alignment variation) was 0.09°, with 0.13° SD. The M angle of axial rotation was 1.27° with SD: 1.19°. Conclusions: The method of accuracy evaluation used in this study can be helpful in establishing a reliable plan.

Perineal perforator switch flap for three-dimensional vulvovaginal reconstruction.

BACKGROUND: Vulvovaginal reconstruction is challenging. In this study, we evaluated the outcomes of vulvovaginal reconstruction with "perineal perforator switch flap" (PPSF) and compared it with other conventional flaps. In addition, the long-term esthetic results were compared with the perineal perforator propeller flap (PPPF), which we previously used. METHODS: We retrospectively reviewed the clinical data of 16 patients (27 flaps) who underwent vulvovaginal reconstruction with PPSF. After tumor resection, perineal perforators close to the genitofemoral sulcus were identified. The flap was designed as an island with the perforator at the center. The flap was elevated while preserving the soft tissue surrounding the pedicle, and transferred to the defect via the subcutaneous tunnel without pedicle skeletonization. RESULTS: All flaps survived and no major surgical complications were observed. The total follow-up period was 16.13±3.38 months. The mean operation time was 79.38±19.65 min, and the initiation of walking and the length of hospitalization were 1.69 ± 0.79 and 5.69 ± 0.79 days, respectively. Perineal function was well preserved. Comparison of esthetic results with PPPF showed that PPSF showed better results in symmetrical and labial shape (2.29 ± 0.73 vs. 3.13 ± 0.81; p=0.015, 2.43 ± 1.02 vs. 3.25 ± 0.68; p=0.031, respectively), and in total score. (10.29 ± 2.16 vs. 12.31 ± 1.82; p=0.017). CONCLUSION: PPSF was technically simple and significantly reduced the duration of operation and the overall recovery time. PPSF also prevented delay in radiation. Therefore, PPSF is a promising method for vulvovaginal reconstruction.

Nitric Oxide Produced by the Antioxidant Activity of Verapamil Improves the Acute Wound Healing Process.

BACKGROUND: Verapamil is used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, hypertrophic scars, and keloids to block transmembrane calcium ion flux. Verapamil has antioxidant activity, which enhances the production of nitric oxide (NO). NO promotes the proliferation of fibroblasts, keratinocytes, endothelial cells, and epithelial cells during wound healing. In this study, we investigated the effect of verapamil and its antioxidant properties on the enhancement of acute wound healing via NO. METHODS: A full-thickness wound healing model was created on the rat dorsal with a silicone ring. The wound closure rate was estimated every 2 days for 14 days. A histological study was performed to evaluate wound healing. Immunofluorescence staining was analyzed for angiogenesis. The expressions of collagen type I (COL I), collagen type III (COL III), and vascular endothelial growth factor (VEGF) were assessed by Western blot. Real-time polymerase chain reaction (qRT-PCR) was performed to examine the expression of endothelial NO synthase and inducible NO synthase, which are related to antioxidant activity in the process of wound healing. RESULTS: The wound closure rate was faster in the verapamil group compared to the control and silicone groups. Histologic analysis revealed capillaries and stratum basale in the verapamil group. Immunofluorescence staining was shown vessel formation in the verapamil group. Western blot and qRT-PCR analysis revealed high expression levels of COL I, VEGF, eNOS, and FGF in the verapamil. CONCLUSION: Verapamil's antioxidant activity enhances NO production in acute wound healing. We suggest that verapamil can be used to promote acute wound healing.

Diametric Comparison between the Thoracodorsal Vessel and Deep Inferior Epigastric Vessel in Breast Reconstruction.

BACKGROUND: In microvascular anastomosis, size discrepancy is common and can increase thrombotic complications. If size differences can be predicted, then vessels of the appropriate size can be selected. This study documented the difference in diameter between the thoracodorsal (TD) vessel and deep inferior epigastric perforator (DIEP) pedicle in each patient who underwent breast reconstruction using free tissue transfer. Patients and Methods. This retrospective study included 32 anastomoses (27 breasts including five cases of supercharged anastomosis) of breast reconstruction with the free DIEP flap and TD recipient between August 2018 and June 2019. In the microscopic view, the caliber of the TD vessel, the largest branch to the serratus anterior muscle, the descending branch, the largest and the second largest branches to the latissimus dorsi muscle, and the DIEP pedicle were measured. RESULTS: The diameter of the deep inferior epigastric artery was similar to that of the descending branch, and their anastomosing rate was 56.3%. The diameter of the deep inferior epigastric vein was similar to the branch to the serratus anterior muscle and the descending branch, and their anastomosing rates were 29.3% and 29.3%, respectively. All flaps were survived; however, in one case, a reoperation was needed to remove the hematoma, in which case fat necrosis occurred as the only complication. CONCLUSION: TD branches of similar size to the DIEP pedicle were prioritized in anastomosis. The descending branch and the branch to the serratus anterior muscle are expected to be good candidates as recipients in breast reconstruction with DIEP free flap. Moreover, supercharged anastomosis of DIEP pedicles can be achieved within TD branches.

Unilateral autologous breast reconstruction with unipedicled and bipedicled deep inferior epigastric artery perforator flap: A review of 168 cases over 3 years.

BACKGROUND: Harvesting a DIEP flap based on bipedicled perforators can enhance vascular perfusion, which can reduce complication rates, minimize fat necrosis, and flap failure. This study summarizes our experience with using unipedicled and bipedicled DIEP flaps for breast reconstruction. PATIENTS AND METHODS: A total of 168 consecutive patients undergoing unilateral breast reconstruction with DIEP flaps over a 3-year period were retrospectively reviewed. Primary microvascular anastomoses were performed to the thoracodorsal vessels in both unipedicled and bipedicled DIEP groups. In bipedicled DIEP flap cases, additional secondary microvascular anastomoses were performed either by extraflap or intraflap options. Clinical characteristics and outcomes were recorded. RESULTS: Unipedicled (n = 89; 53%) and bipedicled flaps were used. Both groups were comparable for mean age, diabetes mellitus, hypertension, smoking, and chemotherapy. BMI was 24.9 ± 3.6 in the unipedicled group and 22.8 ± 2.9 in the bipedicled group (p < .001). The surgical duration was longer in bipedicled group (367 ± 86.5 minu vs 403.7 ± 65.6 min, p < .05) but incidence of fat necrosis decreased in the bipedicle group (24 patients [27%] vs. 7 patients [8.9%] p < .05). There was no flap loss or instance of abdominal hernia in any group. CONCLUSIONS: The bipedicled DIEP flaps may be a feasible option for large breast reconstruction in thin patients. However, the additional microsurgical technical complexity and longer operative time must be considered.

Efficacy of Altered Two-Point Fixation in Zygomaticomaxillary Complex Fracture.

PURPOSE: To reconstruct a zygomaticomaxillary complex (ZMC) fracture, zygomaticofrontal (ZF) suture is the most reliable site to assess anatomical alignment and to secure rigidity. It has been chosen primary site to be fixed, but approach through the lateral eyebrow incision may leave a visible scar. This study suggests altered two-point fixation of ZMC fracture without accessing the ZF suture. METHODS: In the retrospective study, a total of 40 patients with ZMC fracture were divided into two groups (group 1, two-point fixation and group 2, three-point fixation). Patient demographics and follow-up were evaluated, and degree of reduction including cortical gaps of ZF and inferior orbital (IO) area, protruding difference of zygoma, and malar difference using asymmetry index were measured through preoperative and postoperative CT. RESULTS: Preoperatively, the means of ZF displacement, IO displacement, protruding difference of zygoma, and facial asymmetry index between the groups were not statistically different. The result was the same after the operation. However, all variables were significantly different before and after surgery within each group. Moreover, mean operation time was significantly different between groups (P value = 0.026). CONCLUSION: Altered two-point fixation in ZMC fracture excluding incision approaching the ZF provides surgical efficacy and similar surgical outcomes to three-point fixation but offers reduced operation time and fewer complications.

Characterization of cell signaling, morphology, and differentiation potential of human mesenchymal stem cells based on cell adhesion mechanism.

It is essential to characterize the cellular properties of mesenchymal stem cell populations to maintain quality specifications and control in regenerative medicine. Biofunctional materials have been designed as artificial matrices for the stimulation of cell adhesion and specific cellular functions. We have developed recombinant maltose-binding protein (MBP)-fused proteins as artificial adhesion matrices to control human mesenchymal stem cell (hMSC) fate by using an integrin-independent heparin sulfate proteoglycans-mediated cell adhesion. In this study, we characterize cell adhesion-dependent cellular behaviors of human adipose-derived stem cells (hASCs) and human bone marrow stem cells (hBMSCs). We used an MBP-fused basic fibroblast growth factor (MF)-coated surface and fibronectin (FN)-coated surface to restrict and support, respectively, integrin-mediated adhesion. The cells adhered to MF exhibited restricted actin cytoskeleton organization and focal adhesion kinase phosphorylation. The hASCs and hBMSCs exhibited different cytoplasmic projection morphologies on MF. Both hASCs and hBMSCs differentiated more dominantly into osteogenic cells on FN than on MF. In contrast, hASCs differentiated more dominantly into adipogenic cells on MF than on FN, whereas hBMSCs differentiated predominantly into adipogenic cells on FN. The results indicate that hASCs exhibit a competitive differentiation potential (osteogenesis vs. adipogenesis) that depends on the cell adhesion matrix, whereas hBMSCs exhibit both adipogenesis and osteogenesis in integrin-mediated adhesion and thus hBMSCs have noncompetitive differentiation potential. We suggest that comparing differentiation behaviors of hMSCs with the diversity of cell adhesion is an important way to characterize hMSCs for regenerative medicine.

One-stage nipple and breast reconstruction using a deep inferior epigastric perforator flap after a skin-sparing mastectomy.

BACKGROUND: Nipple reconstruction is usually performed as a delayed procedure in patients with breast cancer who undergo skin-sparing mastectomy and breast reconstruction surgery using a deep inferior epigastric perforator (DIEP) flap. The authors designed this study to evaluate the utility of breast reconstruction based on a DIEP flap and immediate nipple reconstruction. METHODS: A retrospective review was conducted of all patients who underwent breast reconstruction performed by a single plastic surgeon from October 2016 to June 2018. Through a questionnaire and chart review, we compared surgical. RESULTS: and complications in cases of single-stage nipple reconstruction after skin-sparing mastectomy (n=17) with patients who underwent delayed nipple reconstruction after skin-sparing mastectomy, modified radical mastectomy, or simple mastectomy (n=7). RESULTS: In a subjective analysis using clinical photos, the immediate nipple reconstruction group had higher scores than their counterparts in an evaluation of the nipple-areolar complex (NAC) (NAC placement, 3.34 vs. 3.04; nipple projection, 3.05 vs. 3.03; nipple size, 3.30 vs. 3.29). No significant differences between the groups were found in terms of complications. CONCLUSIONS: Simultaneous nipple reconstruction is a reliable surgical method with economic advantages. No differences were found in terms of outcomes and complications in comparison to delayed reconstruction. Therefore, surgeons can consider simultaneous nipple reconstruction without particular concerns about asymmetry or necrosis.

Optimal Condition of Isolation from an Adipose Tissue-Derived Stromal Vascular Fraction for the Development of Automated Systems.

BACKGROUND: The stromal vascular fraction (SVF) isolated from adipose tissue, which contains stem cells as well as other cell types, has been applied in various research fields. Although different enzymatic concentrations and treatment durations have been applied to isolate the SVF, optimal conditions have not been established. Thus, we aimed to establish the optimal conditions for isolation of the SVF from adipose tissue by automated systems. METHODS: The SVF was collected from removed adipose tissues of five donors during surgery. The SVF was treated with 0.1% or 0.2% collagenase type I for 20, 40, or 60 min. Then, colony forming unit (CFU) assays and flow cytometry were performed to characterize the adipose stem cells (ASCs). A cytokine array was used to investigate the correlation between colony-formation ability and the secretion of isolated ASCs. RESULTS: Treatment with 0.1% collagenase type I for 60 min resulted in a higher SVF yield, whereas treatment with 0.1% collagenase for 40 min resulted in higher CFU values. In addition, expression of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 in the SVF was higher in the high-CFU group than in the low-CFU group. CONCLUSION: The optimal conditions for isolation of the SVF from adipose tissue were treatment with 0.1% collagenase type I for 40 min. We identified the conditions required for efficient SVF isolation based on high CFU values, and our results will facilitate the development of automated systems.

Reconstruction of wide soft tissue defects with extended anterolateral thigh perforator flap turbocharged technique with anteromedial thigh perforator.

BACKGROUND: The necrotic change may sometimes occur in peripheral parts of the flap when harvesting a wide flap in a patient with a relatively thin thigh in anterolateral thigh (ALT) flap. Here, we explore the prophylactic measure of turbocharging the ALT flap with anteromedial thigh (AMT) perforator based on the circumference of the patient's thigh to reduce the risk of partial flap necrosis for the reconstruction of wide defects. PATIENTS AND METHODS: From January 2015 to December 2017, extended ALT perforator turbocharged flaps were done in nine patients. The majority of patients had post oncological or traumatic defects of upper & lower extremities and groin. The age group ranged from 22 to 86 years. The flap size ranged from 12 × 20 cm to 15 × 28 cm. To augment the viability of the ALT flap, we performed an additional microvascular augmentation of the distal or descending branch of the lateral circumflex artery (LCFA) with the sizable AMT perforator. RESULTS: The extended ALT turbocharged flaps survived completely without peripheral necrosis. The average flap width to circumference ratio of the deep tissues including muscles of thigh was 0.379, and the patients' average harvested flaps width and thigh circumference were 14.3 cm and 40.2 cm, respectively. The mean follow-up was 9.3 months. No complications were recorded during the follow-up. CONCLUSION: We believe that augmentation of the ALT and AMT perforator flaps by turbocharging can repair wide soft tissue defects. This method may be another promising option when reconstructing wide defects in the supine position.

Trochanteric area reconstruction with free flap using perforators as recipients: An alternative and effective option.

BACKGROUND: Reconstructing soft tissue defect on the trochanteric area is challenging. Due to the significant complications associated with regional flap, free tissue transfer is an appropriate option. However, this area has poor recipient vessels. Therefore, we present perforators as suitable recipient vessels to facilitate the use of free flap coverage for the successful reconstruction of defects in the trochanteric area. PATIENTS AND METHODS: From 2013 to 2017, 10 patients underwent free flap reconstruction for soft tissue defects of the trochanteric area. After preoperative computed tomography or magnetic resonance imaging images confirmed the enhanced perforating artery, the skin site was identified by Doppler. If the vessel was confirmed as reliable, the operation was performed in the same manner as for other free flaps. RESULTS: All of the flaps survived, and the perforators selected for surgery included four superficial circumflex iliac artery perforators, four tensor fasciae latae artery perforators, and two inferior gluteal artery perforators. The average diameter of the recipient artery was 0.97 mm and that of the vein was 0.94 mm. One case exhibited arterial insufficiency caused by compression of hematoma; however, complete flap survival was achieved in this case with revised surgery. CONCLUSION: Reconstructing soft tissue defects in the trochanteric area is limited in recipient vessels. However, using a perforator vessel as a recipient facilitates the reconstruction by free flap coverage. This method leads to acceptable flap survival and sufficient padding, with reduced morbidity and collateral injury.

Reduction glossectomy of congenital macroglossia due to lymphangioma.

Macroglossia is a rare clinical condition defined as an enlarged tongue. Macroglossia can cause structural deformities like diastema and disproportionate mandibular growth and present functional disorders such as dysarthria, dysphonia, and respiratory problems. A 7-year-old boy who had lymphangiomatous macroglossia was treated with a reduction glossectomy by anchor-shaped combination of a U-shape and modified key-hole resection. Postoperatively, the reduced tongue was contained completely within the oral cavity, but open bite remained due to prognathism. Sensory and motor nerves to the tongue appeared to be intact, and circulation was adequate. This patient will be monitored for recurrence of tongue enlargement.

Reconstruction of radiation-induced ulcers with free flaps using the perforating vessel as a recipient vessel.

BACKGROUND: Free flaps can be options for coverage of radiation ulcers. However, due to radiation damage, it may be hard to find and dissect a reliable recipient vessel for microsurgical anastomosis. When the radiation fields are targeted for deep tissues, superficial tissues may be less affected by radiation. Therefore, damage to perforator vessels near the skin may be lesser than that to the major vessels in deeper structures. We would like to introduce our experiences of using these less injured perforating vessels within or near the wound as recipient vessels for free flap coverage. PATIENTS AND METHODS: From 2013 to 2015, 11 patients underwent free flap coverage for the treatment of radiation-induced ulceration. The location of ulcers were three cases of thigh, two cases of inguinal area, axilla, trochanteric area, chest wall, lower leg, perineal area, and back. Eleven cases were reconstructed using the anterolateral thigh (ALT) perforator flap, and in one case, the thoracodorsal artery perforator (TDAP) flap was used for inguinal area defect. With preoperative computed tomography, we found perforating vessels around the radiation ulcer. The perforating vessels that were identified before the operation were detected by hand-held Doppler during the operation and meticulous dissection was performed. In all-cases, the perforating vessels were accompanied by vena commitantes. A reliable perforator is one with visible pulsation, strong sound detected on Doppler, and sufficient diameter, preferably larger than 0.6 mm. Anastomosis was performed after confirming that the blood vessel was reliable. RESULTS: The flap sizes ranged from 7 × 6 cm to 24 × 10 cm. No flap total necrosis developed. Patients were followed in the outpatient clinic for 21 to 31 months postoperatively. No patients experienced recurrence of ulceration during the follow-up. CONCLUSIONS: In free flap reconstruction of radiation ulcers, using perforating vessels within or outside the ulcer as recipient vessels provided less damaged vessels and healthier flaps for the defects with minimal wound complications. These perforating vessels can be a good option as recipient vessel for free flap coverage of radiation ulcers.

Multi-dimensional bioinspired tactics using an engineered mussel protein glue-based nanofiber conduit for accelerated functional nerve regeneration.

Limited regenerative capacity of the nervous system makes treating traumatic nerve injuries with conventional polymer-based nerve grafting a challenging task. Consequently, utilizing natural polymers and biomimetic topologies became obvious strategies for nerve conduit designs. As a bioinspired natural polymer from a marine organism, mussel adhesive proteins (MAPs) fused with biofunctional peptides from extracellular matrix (ECM) were engineered for accelerated nerve regeneration by enhancing cell adhesion, proliferation, neural differentiation, and neurite formation. To physically promote contact guidance of neural and Schwann cells and to achieve guided nerve regeneration, MAP was fabricated into an electrospun aligned nanofiber conduit by introducing synthetic polymer poly(lactic-co-glycolic acid) (PLGA) to control solubility and mechanical property. In vitro and in vivo experiments demonstrated that the multi-dimensional tactics of combining adhesiveness from MAP, integrin-mediated interaction from ECM peptides (in particular, IKVAV derived from laminin α1 chain), and contact guidance from aligned nanofibers synergistically accelerated functional nerve regeneration. Thus, MAP-based multi-dimensional approach provides new opportunities for neural regenerative applications including nerve grafting. STATEMENT OF SIGNIFICANCE: Findings in neural regeneration indicate that a bioinspired polymer-based nerve conduit design should harmoniously constitute various factors, such as biocompatibility, neurotrophic molecule, biodegradability, and contact guidance. Here, we engineered three fusion proteins of mussel-derived adhesive protein with ECM-derived biofunctional peptides to simultaneously provide biocompatibility and integrin-based interactions. In addition, a fabrication of robust aligned nanofiber conduits containing the fusion proteins realized suitable biodegradability and contact guidance. Thus, our multi-dimensional strategy on conduit design provided outstanding biocompatibility, biodegradability, integrin-interaction, and contact guidance to achieve an accelerated functional nerve regeneration. We believe that our bioengineered mussel adhesive protein-based multi-dimensional strategy would offer new insights into the design of nerve tissue engineering biomaterials.

Three-dimensional printing of a patient-specific engineered nasal cartilage for augmentative rhinoplasty.

Autologous cartilages or synthetic nasal implants have been utilized in augmentative rhinoplasty to reconstruct the nasal shape for therapeutic and cosmetic purposes. Autologous cartilage is considered to be an ideal graft, but has drawbacks, such as limited cartilage source, requirements of additional surgery for obtaining autologous cartilage, and donor site morbidity. In contrast, synthetic nasal implants are abundantly available but have low biocompatibility than the autologous cartilages. Moreover, the currently used nasal cartilage grafts involve additional reshaping processes, by meticulous manual carving during surgery to fit the diverse nose shape of each patient. The final shapes of the manually tailored implants are highly dependent on the surgeons' proficiency and often result in patient dissatisfaction and even undesired separation of the implant. This study describes a new process of rhinoplasty, which integrates three-dimensional printing and tissue engineering approaches. We established a serial procedure based on computer-aided design to generate a three-dimensional model of customized nasal implant, and the model was fabricated through three-dimensional printing. An engineered nasal cartilage implant was generated by injecting cartilage-derived hydrogel containing human adipose-derived stem cells into the implant containing the octahedral interior architecture. We observed remarkable expression levels of chondrogenic markers from the human adipose-derived stem cells grown in the engineered nasal cartilage with the cartilage-derived hydrogel. In addition, the engineered nasal cartilage, which was implanted into mouse subcutaneous region, exhibited maintenance of the exquisite shape and structure, and striking formation of the cartilaginous tissues for 12 weeks. We expect that the developed process, which combines computer-aided design, three-dimensional printing, and tissue-derived hydrogel, would be beneficial in generating implants of other types of tissue.

Nasal Reconstruction Using a Customized Three-Dimensional-Printed Stent for Congenital Arhinia: Three-Year Follow-up.

A male Mongolian child with a complete congenital absence of both nose and nasal passage had a poor survival prognosis due to respiratory distress. To enable his survival, a new nose capable of conferring respiratory function was constructed. Following reconstructive surgery, an absence of mucoepithelium in the nasal passage can lead to rhinostenosis. To avoid this complication, a custom-made nasal silicone stent was created using three-dimensional (3D) printing technology in conjunction with the patient's computed tomography data. The stent was implanted for 2 months to maintain the shape and size of the nasal passage. At 2 months after stent implantation, the mucoepithelium tissue in the passage had successfully regenerated with no immune reaction. Three years after stent removal, respiratory function, nasal passage structure, and external nose shape were maintained without additional medical care. These results indicate the successful nasal reconstruction in an arhinia patient using a customized, 3D-printed nasal stent. Laryngoscope, 129:582-585, 2019.

Metachronous malignant tumors in ipsilateral salivary glands.

Salivary gland tumors usually appear in solitary mass in single salivary gland. The coexistence of tumors with different histological types occurring within a unilateral parotid gland is an extremely rare event. We experienced a case which two different types of malignant tumors developed at different time points in same gland; metachronous tumors. The second tumor was excised widely and reconstruction was performed by free tissue transfer. Sensory and motor nerve to the left cheek appeared to be intact, and circulation was adequate. This rare case was presented in this article.