Application of multislice computed tomography volume rendering and 3D printing technique of costal cartilage for auricular reconstruction

To investigate the application of medpor and split-thickness skin graft in formation of cranioauricular sulcus during auricular reconstruction with Nagata method. The first stage operation was fulfilled according to the Nagata two-stage method which involves fabrication and grafting of the costal cartilage framework. The second-stage ear elevation operation was undertaken 6 months later to form the cranioauricular sulcus. Split-thickness skin was taken from temporal and accipital area. After releasing the auricular framework and transplanting C shaped medpor at the rear side of framework, the temporaparietal fascia flap was transferred to cover postauricular medpor and framework. Then the split-thickness skin graft was implant on the fascia surface. From July 2010 to August 2012, 20 cases (22 ears) were treated. Partial necrosis of temporaparietal fascia flap and framework exposure happened in 1 case. Successful ear reconstruction was achieved in other cases with satisfactory cranioauricular sulcus during the follow-up period of 6-18 months (average, 13 months). The application of medpor and split-thickness skin graft in the ear elevation of Nagata method for auricular reconstruction for microtia can achieve satisfactory results. It not only avoids the obvious scar in the donor site due to harvesting full-thickness and intermediate-thickness skin, but also reduces chest trauma due to harvesting costal cartilage.

Objective To summarize and explore the clinical effect of auricular reconstruction with autologous costal cartilage grafts and delaying postauricular skin flap.Methods The procedure involved three stages.The first stage was the delay procedure of postauricular skin flap.The second stage was the auricular reconstruction with autologous costal cartilage grafts and delaying postauricular skin flap about 3 weeks after the delay procedure.The third stage involved construction of tragus and conchal cavity and other local correction 6 months or longer after the second stage surgery.The clinical effect,patients' satisfaction and complication were observed.Results This method was used in 28 patients,31 ears of congenital microtia.23 cases completed auricular reconstruction with three stages,the other 8 cases completed only two stages.All auricular reconstruction were successful.The location,size and shape of reconstructive ears were good.The complications were few.The patients or their relatives were basically satisfactory.Conclusions Auricular reconstruction with autologous costal cartilage grafts and delaying postauricular skin flap is a safe and effective method. Key words: Auricular reconstruction; Microtia; Autologous costal cartilage; Auricle stents; Flap delay

Objective To explore a 1∶1 2D printing method of rib cartilage based on CT scanning in assisting ear framework fabrication for auricular reconstruction. Methods From January 2016 to January 2017, 73 cases of microtia aging from 5 to 7 referred to our department. A 1∶1 2D printing of rib cartilage based on CT scanning was applied in preoperative assessment and measurments of bilateral sixth, seventh and eighth costal cartilage were completed before the surgery. Personalized rib cartilage ear framework fabrication was determined by the measurements. Results Among the 73 cases, 58 cases received auricular reconstruction successfully. There were 15 patients whose rib cartilages did not meet the requirements and postponed the surgery. The patients who underwent auricular reconstruction were followed up for 6 to 12 months (average, 9 months). During the follow-up, 52 cases had satisfactory outcomes in size, shape, symmetry and details. No deformation of reconstructed ears or chest wall was found during the follow-up. Conclusions The 1∶1 2D printing based on CT scanning is a simple and timesaving way to evaluate the rib cartilage. It can be beneficial to save the amount of cartilage and improve the personalized ear framework fabrication. Key words: Reconstruction of auricle; Costal cartilage; Framework

To investigate a method for total reconstruction of auricle. 90 patients (101 ears) with congenital microtia underwent two-stage operations for auricular reconstruction. The first stage involved fabrication and grafting of autologous costal cartilage, removing the remnant ear cartilage, embedding the framework into local flap of the mastoid region, transferring the remnant ear lobule flap to link to the inferior framework. The second stage was creating an auriculocephalic sulcus. The reconstruction was performed 4 - 12 months after the first surgery. Skin incision was made 5 mm lateral side of the posterior margin of the auricle. The ear framework carrying a thick ear fascia was separated from the side of the head, the frames of the costal cartilage banked at the first operation were harvested, shaved and transplanted to the posterior wall of the concha with sutures; adjust stand position and angle, so that made the ear shape, position, axis, close to the healthy ear, and auriculocephalic angle was slightly larger than the contralateral ear. Two random flap was designed with superior on the root of the helix and in the inferior-posterior direction of the inferior mastoid area, two flapes were elevated and transplanted to posterior auricular sulcus to cover the grafted cartilage. Skin graft was performed in the remaining raw surface. A total of 90 patients were operated, all of 101 constructed ears achieved satisfied or near satisfied shapes. Five cases of partial skin flap necrosis were caused by pedicle impairment. Exposure of cartilage framework happened in two cases. The auriculocephalic sulcus of four cases diminished after the second stage operation. Three month to two-year follow-up of 67 patients showed that the reconstructed ears were satisfied with the results, including good shapes and steady auriculocephalic angles. The method is a simple, safe and reliable method for total aural reconstruction.

Objectives To explore the differences in signal pathway and gene expression related to the pathogenesis of congenital microtia by the in-depth analysis of DNA methylation profiling of auricular chondrocytes from congenital microtia patients. Methods Genome wide methylation profile of congenital microtia was obtained by MeDIP chip technology, and analyzed by Gene ontology (GO) and Pathway analysis. The gene expression levels of Wnt1 and Wnt11 were evaluated by Real-time PCR in the auricular cartilage from the healthy side and affected side of the congenital microtia patients , and healthy controls. Results The GO and Pathway assay showed that Wnt signal pathway was enriched in differential methylated levels. The Wnt1 and Wnt11 genes were with higher methylation in the promoter region and CpG islands in healthy control group than that in microtia group, in addition the methylation level in the affected side auricular cartilage was lower than that in the healthy side. There was no difference in Wnt1 and Wnt11 gene expression in microtia patients and healthy controls. The higher Wnt11 gene expression was detected in the affected side residual cartilage tissues than in the healthy side cartilage tissues of the same congenital microtia patient. Conclusions The over expression of Wnt11 during embryonic development might be associated with the pathogenesis of congenital microtia. The mechanism of the difference in methylation levles of Wnt11 affecting pathogenesis of congenital microtia needs further research. Key words: Congenital microtia; DNA chip; Signaling pathway

Objective To evaluate whether restricted breathing movement by wearing elastic chest belt within half a year postoperatively could decrease the incidence of chest wall deformity after costal cartilage harvesting. Methods The contour of chests of the patients receiving the third-stage operation of auricular reconstruction was assessed 1 year after costal cartilage harvesting with history collection and physical examination. The incidence of costal wall deformity was summarized and compared by wearing elastic chest belt or not within half a year postoperatively. Logistic regression was used to analyze the significance of results. Results Thirty-eight eligible patients were enrolled in the study. The incidence of chest wall deformity in patients wearing chest elastic chest belt as requested for half a year was lower (64.7% vs. 95.2%), and the difference was statistically significant, OR 10.9, 95%CI[1.16, 102.60], P=0.037. Conclusions Restricted breathing movement by wearing elastic chest belt within half a year postoperatively could decrease the incidence of chest wall deformity following costal cartilage harvesting through decreasing the traction force caused by respiratory muscles and intrathoracic negative pressure. Key words: Costal cartilage harvest; Chest wall deformity; Elastic belt

Objective In order to achieve superior aesthetic outcomes of reconstructed ear, analyze and summarize clinical therapeutic effect in completely applying expanded retroauricular flap to encapsulate cartilage scaffold in total auricular reconstruction. Methods From January 2016 to October 2017, fifty-three congenital microtia patients were treated. A kidney-shaped tissue expander with 50 ml capacity was embedded under retroauricular skin in the first-stage. After excessive expansion to 70 ml and remaining stable for 4 weeks, secondary operation was performed to completely encapsulate cartilage scaffold with expanded retroauricular skin. Postoperative follow-up was carried out on a routine basis. Results All patients had undergone operations successfully with primary healing of incision. Blood supply of the retroauricular flaps was excellent, and cartilage scaffolds totally survived with no infection and absorption. Satisfactory aesthetic outcome along with clear structure, reasonable symmetry and suitable auriculocephalic angle was acquired in all cases. No color aberration was observed between the front and back side of reconstructed ear. Scars of retroauricular incisions and costal cartilage harvesting incisions were unconspicuous. Conclusions Only using expansive retroauricular flap to fully cover reconstructed cartilage scaffold is reasonable and simple without skin grafting, which is worthy of more application in microtia treatment. Key words: Microtia; Surgical flap; Soft tissue expander; Reconstruction of auricle

To explore the fabrication and application of three-dimensional autogenous cartilage framework in auricular reconstruction. The process of fabrication of three-dimensional cartilage framework consisted of cartilage harvesting, carving and assembling the cartilage. The rib cartilage was harvested separately. The three-dimensional framework was composed of three main parts:the helix, the base and the pad, at different layer. The framework was fabricated according to the development of rib cartilage and contour and height of the reconstructed ear. From January 1992 to December 2006, 5,248 patients of microtia were treated with 6,252 autogenous cartilage frameworks. The three-dimensional framework is easily manipulated. The reconstructed ears look natural and had an erect contour. This method can effectively use the cartilage.

Objective To propose a practical method for moderate-to-server cup-ear correction.Methods Auricular reconstruction was performed in a manner of two-stage approach with mastoid flap and costal cartilage support.In the first stage,the autogenous costal cartilage framework was inserted under the retroauricular mastoid skin flap.The corrected ear was raised in the second operation and wound was closed with grafting skin.Results Satisfaction of appearance was achieved for totally 18 cases except one case of partly necrosis of cartilage.They were followed-up for 3-26 months.Conclusions This integrative two-stage approach of mastoid flap combining three dimensional costal cartilage is safe and effctive for moderate to severe cup-ear correction,which brings about good appearances and symmetry.The complications are in control. Key words: Cup ear; Skin flap; Deformity

To introduce a modified surgery for total auriculoplasty and the experience in one hundred and forty-six cases (155 ears). The procedure was a two-stage operation. The first stage involved fabrication and grafting of a costal cartilage framework. A U-shaped skin incision was made on the posterior edge of the lobule and the remnant ear cartilage was removed completely. The area for the insertion of the cartilage framework was undermined. Skin flaps were sutured after insertion of the cartilage framework. The second-stage surgery was usually performed six months after the first-stage operation. The reconstructed auricle was elevated, and a costal cartilage block was fixed to the posterior part of the auricle. A temporoparietal fascia flap was then used to cover the costal cartilage block. Finally, the posterior aspect of the projected auricle was covered with a spit-thickness skin graft. The incisions healed in one hundred and forty-one patients (150 ears) after the first stage operation. Partial necrosis of the postauricular flap was observed in five cases (5 ears) after the first stage operation, but no exposure or absorption of the cartilage took place. The skin grafts survived in one hundred and thirty-nine cases (147 ears) after the second-stage surgery. Partial necrosis of the skin graft was observed in seven cases (8 ears), but healed after one-week of dressing changes. Ninety-four cases (97 ears) were followed up, but fifty-two cases (58 ears) were lost to follow up. The follow-up at six months to two years showed satisfactory contour and projection of the constructed ears. This two-stage surgery is simple and ideal for auricloplasty with few complications.

Objective To study the tissue size, calcification characteristics and the correlation between calcification and age and lateral side of 6, 7 and 8 costal cartilage in women, so as to provide reference for clinical application. Methods From the radiology storage center of Second Xiangya Hospital, 70 cases of female costal cartilage were treated with dual-source CT three-dimensional reconstruction. The reconstructed images were treated with maximum intensity projection (MIP) and volume reconstruction (VR). The length, width and thickness of bilateral 6, 7 and 8 costal cartilage were measured by VR images, and the correlation between calcification rate, calcification degree, calcification type, calcification location, calcification with age and side was observed and analyzed on VR and MIP images. The data were analyzed by SPSS 20.0 and compared by corresponding statistical method, including independent sample t test, chi-square test, logistic regression analysis and variance analysis. Results (1) The length of costal cartilage on the left was (98.7 ±12.7) mm, (132.8 ±13.8) mm, (81.5 ±11.6) mm, width (12.6 ±1.5) mm, (11.0 ±1.4) mm, (7.4 ±1.1) mm, thickness (8.1 ±0.5) mm, (7.7 ±0.6) mm, (6.6 ±0.6) mm. On the right side, the length of costal cartilage was (95.8 ±11.3) mm, (133.1 ±12.0) mm, (81.7 ±12.3) mm, width (12.2 ±1.4) mm, (11.11 ±1.5) mm, (7.4 ±1.1) mm, thickness (8.2 ±0.6) mm, (7.7 ±0.5) mm, (6.5 ±0.6) mm. There was no significant difference in the length, width and thickness of the left and right sides of the costal cartilage in the same sequence (P>0.05). There were significant differences in length, width and thickness between unilateral costal cartilage with different ordinal numbers (P 0.05). There was no significant difference in the total calcification type between left and right, the total calcification location and the total calcification degree count (P>0.05). There was also no significant difference between the two groups (P>0.05). There was no significant difference in the calcification rate between the left and right sides of the 6th, 7th and 8th costal cartilage, but there was significant difference in the total calcification types of the 6th, 7th and 8th costal cartilage (The chi-square was equal to 61.541, P value was less than 0.001). (3)The relationship between calcification rate and age was analyzed by univariate analysis and logistic regression equation. The higher the age, the higher the calcification rate. The relationship between the calcification degree and age of the 6th, 7th and 8th costal cartilage was tested by variance test, and the regression equation showed that the calcification degree of the 6th, 7th and 8th costal cartilage was higher with the age. Conclusions Preoperative three-dimensional reconstruction and image post-processing of costal cartilage with dual-source CT can accurately measure the amount of cartilage tissue and define the characteristics of calcification, so as to guide the clinical selection of costal cartilage that meets the requirements of operative method. In female patients of different ages undergoing rhinoplasty and external ear reconstruction, the calcification rate of costal cartilage increased with age, but there was no positive correlation. With the increase of calcification with age, artificial materials can be used for cases with severe calcification to avoid the blindness of surgery. Key words: Computerized tomography; Costal cartilage; Three-dimensional reconstruction; Maximum intensity projection; Volume reconstruction; Tissue volume; Calcification

Costal cartilage is a promising donor source of chondrocytes to alleviate cell scarcity in articular cartilage tissue engineering. Limited knowledge exists, however, on costal cartilage characteristics. This study describes the characterization of costal cartilage and articular cartilage properties and compares neocartilage engineered with costal chondrocytes to native articular cartilage, all within a sheep model. Specifically, we (a) quantitatively characterized the properties of costal cartilage in comparison to patellofemoral articular cartilage, and (b) evaluated the quality of neocartilage derived from costal chondrocytes for potential use in articular cartilage regeneration. Ovine costal and articular cartilages from various topographical locations were characterized mechanically, biochemically, and histologically. Costal cartilage was stiffer in compression but softer and weaker in tension than articular cartilage. These differences were attributed to high amounts of glycosaminoglycans and mineralization and a low amount of collagen in costal cartilage. Compared to articular cartilage, costal cartilage was more densely populated with chondrocytes, rendering it an excellent chondrocyte source. In terms of tissue engineering, using the self-assembling process, costal chondrocytes formed articular cartilage-like neocartilage. Quantitatively compared via a functionality index, neocartilage achieved 55% of the medial condyle cartilage mechanical and biochemical properties. This characterization study highlighted the differences between costal and articular cartilages in native forms and demonstrated that costal cartilage is a valuable source of chondrocytes suitable for articular cartilage regeneration strategies.

Objective To investigate the modification of the classic techniques of total auricle reconstruction with skin expansion, and its clinical application. Methods We performed three-dimensional measurement of the normal auricle and the expanded flap on 150 microtia patients. According to the data, we carried out total auricle reconstruction using extended postauricle expanded flap techniques for 82 patients of the group. Firstly, a 50 ml kidney-shaped expander was inserted subcutaneously in the mastoid region. Approximately 65 ml saline was injected in about 30 days, and expansion was kept without injection for another 30 days. In the second stage, we removed the expander and dissected the scalp 4-5 cm around the expanded skin, to make a composite flap consisted of expanded skin and extend scalp. Then we used the flap to encapsulate the three-dimensional rib cartilage framework to accomplish total auricle reconstruction. Results The blood supply and venous drainage of the flap was good. No obvious postoperative flap swelling was observed. Only 2 cases of helix skin necrosis happened in 48 hours after operation. Small area of skin defect was treated by debridement and suture, while larger area of skin defect was repaired with postauricular fascia flap and free skin graft. Postoperative follow-up period was 4-15 months, about 6.7 months in average. Bilateral ear size and position were similar with clear structures and shapes. Helix seemed more slim, auriculocephalic sulcus was obvious, auriculocephalic angle was similar to the other side. There was no color abberration between the front and back side of reconstructed ear. Scars of retroauricular hairline incision and costal cartilage harvesting incision were not obvious. Conclusions The novel surgical techniques is reasonable and simple without fascia flap or skin graft, which is worthy of application by more plastic surgeons. Key words: Microtia; Skin soft tissue expansion; Auricle reconstruction

Microtia is a congenital deformity of the ear with an incidence of about 0.8-4.2 per 10,000 births. Total auricular reconstruction is the preferred treatment of microtia at present, and one of the core technologies is the preparation of cartilage scaffolds. Autologous costal cartilage is recognized as the best material source for constructing scaffold platforms. However, costal cartilage harvest can lead to donor-site injuries such as pneumothorax, postoperative pain, chest wall scar and deformity. Therefore, with the need of alternative to autologous cartilage, in vitro and in vivo studies of biomaterial scaffolds and cartilage tissue engineering have gradually become novel research hot points in auricular reconstruction research. Tissue-engineered cartilage possesses obvious advantages including non-rejection, minimally invasive or non-invasive, the potential of large-scale production to ensure sufficient donors and controllable morphology. Exploration and advancements of tissue-engineered cartilaginous framework are also emerging in aspects including three-dimensional biomaterial scaffolds, acquisition of seed cells and chondrocytes, 3D printing techniques, inducing factors for chondrogenesis and so on, which has greatly promoted the research process of biomaterial substitute. This review discussed the development, current application and research progress of cartilage tissue engineering in auricular reconstruction, particularly the usage and creation of biomaterial scaffolds. The development and selection of various types of seed cells and inducing factors to stimulate chondrogenic differentiation in auricular cartilage were also highlighted. There are still confronted challenges before the clinical application becomes widely available for patients, and its long-term effect remains to be evaluated. We hope to provide guidance for future research directions of biomaterials as an alternative to autologous cartilage in ear reconstruction, and finally benefit the transformation and clinical application of cartilage tissue engineering and biomaterials in microtia treatment.

Magnetic nanoparticles with the ability to absorb laser radiation are the perspective agents for the early diagnostics and laser therapy of degenerative cartilage. The effect of starch stabilized magnetite nanoparticles (SSNPs) on the cartilage structure components has never been studied before. The aim of the work is to establish the Erbium:glass laser effect on costal and articular cartilage impregnated with SSNPs. Porcine articular and costal cartilage disks (2.0 mm in diameter and 1.5-2 mm in thickness) were impregnated with SSNPs and irradiated using a 1.56 μm laser in therapeutic laser setting. The one sample group underwent the second irradiation after the SSNPs impregnation. The samples were analyzed by the means of histology, histochemistry and transmission electron microscopy (TEM) to reveal the alterations of cells, glycosaminoglycans and collagen network. The irradiated cartilage demonstrates the higher content of cell alterations than the intact one due to the heat and mechanical affection in the course of laser irradiation. However the alterations are localized at the areas near the irradiated surfaces and not dramatic. The impregnation of SSNPs does not cause any additional cell alterations. For both costal and articular cartilage the matrix alterations of irradiated samples are not critical: there is the slight decrease in acid proteoglycan content at the irradiated areas while the collagen network is not altered. Distribution and localization of impregnated SSNPs is described: agglomerates of 150-230 nm are observed located at the borders between matrix and cell lacunas of articular cartilage; SSNPs of 15-45 nm are found in the collagen network of costal cartilage. It was shown that SSNPs do not appreciably affect the structural components of both articular and costal cartilage and can be safely used for the laser diagnostics and therapy. The area of structural alterations is diffuse and local as the result of the mechanical and heat effect of laser impact. SSNPs reveal the areas of the structural alterations of cartilage matrix and give information about the size of the pores and defects.