3D Printed Multiphasic Scaffolds for Osteochondral Repair: Challenges and Opportunities

Osteochondral (OC) defects are debilitating joint injuries characterized by the loss of full thickness articular cartilage along with the underlying calcified cartilage through to the subchondral bone. While current surgical treatments can provide some relief from pain, none can fully repair all the components of the OC unit and restore its native function. Engineering OC tissue is challenging due to the presence of the three distinct tissue regions. Recent advances in additive manufacturing provide unprecedented control over the internal microstructure of bioscaffolds, the patterning of growth factors and the encapsulation of potentially regenerative cells. These developments are ushering in a new paradigm of 'multiphasic' scaffold designs in which the optimal micro-environment for each tissue region is individually crafted. Although the adoption of these techniques provides new opportunities in OC research, it also introduces challenges, such as creating tissue interfaces, integrating multiple fabrication techniques and co-culturing different cells within the same construct. This review captures the considerations and capabilities in developing 3D printed OC scaffolds, including materials, fabrication techniques, mechanical function, biological components and design.

Institutional Experience and Orthoplastic Collaboration Associated with Improved Flap-based Limb Salvage Outcomes

BACKGROUND

Flap-based limb salvage surgery balances the morbidity and complexity of soft tissue transfer against the potential benefit of preserving a functional limb when faced with a traumatized extremity with composite tissue injury. These composite tissue injuries are well suited for multidisciplinary management between orthopaedic and plastic surgeons. Thus, it makes intuitive sense that a collaborative, orthoplastic approach to flap-based limb salvage surgery can result in improved outcomes with decreased risk of flap failure and other complications, raising the question of whether this orthoplastic team approach should be the new standard of care in limb salvage surgery.

QUESTIONS/PURPOSES

(1) Is there an association between increased annual institutional volume and perioperative complications to include free and local flap failure (substantial flap viability loss necessitating return to the operating room for debridement of a major portion or all of the flap or amputation)? (2) Is an integrated orthoplastic collaborative approach to managing combat-related traumatic injuries of the extremities individually associated with a decreased risk of flap failure and overall flap-related complications? (3) What other factors, such as location of injury, injury severity score, and initial inpatient length of stay, were associated with flap necrosis and flap-related complications?

METHODS

We performed a retrospective review of the electronic medical records of all patients who underwent flap-based limb salvage for combat-related extremity trauma in the United States Military Health System's National Capital Region between January 1, 2003 and December 31, 2012. In total, 307 patients underwent 330 flap procedures. Of the 330 flaps, 59% (195) were local or pedicled flaps and 41% (135) were free flaps. Patients were primarily male (99% [303]), with a median (interquartile range) age of 24 years old (IQR 21 to 29), and 87% (267 of 307) of injuries were sustained from a blast mechanism. We collected data on patient demographics, annual case volume involving flap coverage of extremities, mechanism of injury, flap characteristics, perioperative complications, flap failure, flap revision, isolated orthopaedic management versus an integrated orthoplastic approach, and other salvage procedures. For the purposes of this study, orthoplastic management refers to operative management of flap coverage with microvascular surgeons present for soft tissue transfer after initial debridement and fixation by orthopaedic surgery. The orthoplastic management was implemented on a case-by-case basis based on individual injury characteristics and the surgeon's discretion with no formal starting point. When implemented, the orthoplastic team consisted of an orthopaedic surgeon and microvascular-trained hand surgeons and/or plastic surgeons. In all, 77% (254 of 330) of flaps were performed using this model. We considered perioperative flap complications as any complication (such as infection, hematoma, dehiscence, congestion, or necrosis) resulting in return to the operating room for re-evaluation, correction, or partial debridement of the flap. We defined flap failure as a return to the operating room for debridement of a major portion of the flap or amputation secondary to complete or near-complete loss of flap viability. Of the flap procedures, 12% (40 of 330) were classified as a failure and 14% (46 of 330) experienced complications necessitating return to the operating room. Over the study period, free flaps were not more likely to fail than pedicled flaps (11% versus 13%; p = 0.52) or have complications necessitating additional procedures (14% versus 16%; p = 0.65).

RESULTS

Our multiple linear regression model demonstrated that an increased number of free flaps performed in our institution annually in any given year was associated with a lower likelihood of failure per case (r = -0.17; p = 0.03) and lower likelihood of reoperation for each flap (r = -0.34; p < 0.001), after adjusting for injury severity and team type (orthoplastic or orthopaedic only). We observed a similar relationship for pedicled flaps, with increased annual case volume associated with a decreased risk of flap failure and reoperation per case after adjusting for injury severity and team type (r = -0.21; p = 0.003 and r = -0.22; p < 0.001, respectively). Employment of a collaborative orthoplastic team approach was associated with decreased flap failures (odds ratio 0.4 [95% confidence interval 0.2 to 0.9]; p = 0.02). Factors associated with flap failure included a lower extremity flap (OR 2.7 [95% CI 1.3 to 6.2]; p = 0.01) and use of muscle flaps (OR 2.3 [95% CI 1.1 to 5.3]; p = 0.02).

CONCLUSION

Although prior reports of combat-related extremity trauma have described greater salvage success with the use of pedicled flaps, these reports are biased by institutional inexperience with free tissue transfer, the lack of a coordinated multiservice effort, and severity of injury bias (the most severe injuries often result in free tissue transfer). Our institutional experience, alongside a growing body of literature regarding complex extremity trauma in the civilian setting, suggest a benefit to free tissue coverage to treat complex extremity trauma with adequate practice volume and collaboration. We demonstrated that flap failure and flap-related complications are inversely associated with institutional experience regardless of flap type. Additionally, a collaborative orthoplastic approach was associated with decreased flap failures. However, these results must be interpreted with consideration for potential confounding between the increased case volume coinciding with more frequent collaboration between orthopaedic and plastic surgeons. Given these findings, consideration of an orthoplastic approach at high-volume institutions to address soft tissue coverage in complex extremity trauma may lead to decreased flap failure rates.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Microglia replacement by microglia transplantation (Mr MT) in the adult mouse brain

Mutations in microglia may cause brain disorders. Replacement of dysfunctional microglia by allogeneic wild-type microglia from bone marrow transplantation (Mr BMT) or peripheral blood can correct the gene deficiency at the brain-wide scale but cannot achieve precise replacement at specific brain regions. Here, we introduce a strategy with potential clinical relevance-microglia replacement by microglia transplantation (Mr MT), combining tamoxifen-induced ablation of Mr BMT cells and intracranial injection of microglia to mouse brain, to achieve region-sepcific microglia replacement. The original abbreviation of this microglia replacement strategy is mrMT. We hereby change the name to Mr MT. For complete details on the use and execution of this protocol, please refer to Xu et al. (2020).

Molecular characterization of the nitric oxide synthase gene and its immunomodulation of nitric oxide production in the triangle shell mussel (Hyriopsis cumingii)

Nitric oxide synthase (NOS) is a critical enzyme that catalyzes nitric oxide biosynthesis and orchestrates various immunological responses mediated by nitric oxide (NO) in host animals. In this study, the NOS gene was identified in the triangle shell mussel (Hyriopsis cumingii) (HcNOS). HcNOS was highly conserved in the characteristic gene structures of NOS. Phylogenetic analysis suggested that HcNOS was a typical invertebrate NOS. Further gene expression analysis, NOS activity assays and nitric oxide content measurements demonstrated the inducibility of HcNOS in responses to lipopolysaccharide (LPS) challenge and during tissue transplantation. Of note, mantle grafting induced a prolonged HcNOS/NO response, suggesting that through the HcNOS/NO system, multiple immunomodulators may play decisive roles in tissue grafting in triangle shell mussels. Thus, HcNOS appears to be a crucial player in responding to both bacterial infection and tissue transplantation.

Ex Vivo and In Vivo Analysis of a Novel Porcine Aortic Patch for Vascular Reconstruction

(1) Background: The aim of the present study was the biocompatibility analysis of a novel xenogeneic vascular graft material (PAP) based on native collagen won from porcine aorta using the subcutaneous implantation model up to 120 days post implantationem. As a control, an already commercially available collagen-based vessel graft (XenoSure®) based on bovine pericardium was used. Another focus was to analyze the (ultra-) structure and the purification effort. (2) Methods: Established methodologies such as the histological material analysis and the conduct of the subcutaneous implantation model in Wistar rats were applied. Moreover, established methods combining histological, immunohistochemical, and histomorphometrical procedures were applied to analyze the tissue reactions to the vessel graft materials, including the induction of pro- and anti-inflammatory macrophages to test the immune response. (3) Results: The results showed that the PAP implants induced a special cellular infiltration and host tissue integration based on its three different parts based on the different layers of the donor tissue. Thereby, these material parts induced a vascularization pattern that branches to all parts of the graft and altogether a balanced immune tissue reaction in contrast to the control material. (4) Conclusions: PAP implants seemed to be advantageous in many aspects: (i) cellular infiltration and host tissue integration, (ii) vascularization pattern that branches to all parts of the graft, and (iii) balanced immune tissue reaction that can result in less scar tissue and enhanced integrative healing patterns. Moreover, the unique trans-implant vascularization can provide unprecedented anti-infection properties that can avoid material-related bacterial infections.

iNKT cells coordinate immune pathways to enable engraftment in nonconditioned hosts

Invariant natural killer T (iNKT) cells are a conserved population of innate T lymphocytes that interact with key antigen-presenting cells to modulate adaptive T-cell responses in ways that can either promote protective immunity, or limit pathological immune activation. Understanding the immunological networks engaged by iNKT cells to mediate these opposing functions is a key pre-requisite to effectively using iNKT cells for therapeutic applications. Using a human umbilical cord blood xenotransplantation model, we show here that co-transplanted allogeneic CD4+ iNKT cells interact with monocytes and T cells in the graft to coordinate pro-hematopoietic and immunoregulatory pathways. The nexus of iNKT cells, monocytes, and cord blood T cells led to the release of cytokines (IL-3, GM-CSF) that enhance hematopoietic stem and progenitor cell activity, and concurrently induced PGE2-mediated suppression of T-cell inflammatory responses that limit hematopoietic stem and progenitor cell engraftment. This resulted in successful long-term hematopoietic engraftment without pretransplant conditioning, including multi-lineage human chimerism and colonization of the spleen by antibody-producing human B cells. These results highlight the potential for using iNKT cellular immunotherapy to improve rates of hematopoietic engraftment independently of pretransplant conditioning.

Effectiveness of Repair Techniques for Spinal Dural Tears: A Systematic Review

BACKGROUND

Incidental or intentional durotomy in spine surgery is associated with a risk of cerebrospinal fluid (CSF) leakage and reoperation. Several strategies have been introduced, but the incomplete closure is still relatively frequent and troublesome. In this study, we review current evidence on spinal dural repair strategies and evaluate their efficacy.

METHODS

PubMed, Web of Science, and Scopus were used to search primary studies about the repair of the spinal dura with different techniques. Of 265 articles found, 11 studies, which specified repair techniques and postoperative outcomes, were included for qualitative and quantitative analysis. The primary outcomes were CSF leakage and postoperative infection.

RESULTS

The outcomes of different dural repair techniques were available in 776 cases. Pooled analysis of 11 studies demonstrated that the most commonly used technique was a combination of primary closure, patch or graft, and sealant (22.7%, 176/776). A combination of primary closure and patch or graft resulted in the lowest rate of CSF leakage (5.5%, 7/128). In this study, sealants as an adjunct to primary closure (13.7%, 18/131) did not significantly reduce the rate of CSF leakage compared with primary closure alone (17.6%, 18/102). The rates of infection and postoperative neurologic deficit were similar regardless of the repair techniques.

CONCLUSIONS

Although the use of sealants has become prevalent, available sealants as an adjunct to primary closure did not reduce the rate of CSF leakage compared with primary closure. The combination of primary closure and patches or grafts could be effective in decreasing postoperative CSF leakage.

Inferior pedicle breast reduction and long nipple-to-inframammary fold distance: How long is safe?

BACKGROUND

Free nipple grafting indications in breast reduction surgery are outdated. Safety of inferior pedicle technique for large resections and long pedicles has not been clearly defined. We evaluated patients who underwent inferior pedicle reduction mammoplasty to define the safety constraints of the inferior pedicle.

METHODS

A retrospective review of patients who underwent inferior pedicle reduction mammoplasty due to symptomatic macromastia at Mayo Clinic over a six-year period was conducted. Patients with prior breast surgeries were excluded. Demographics, breast measurements, and surgical outcomes were collected. Univariate and multivariate analyses were performed to assess for predictors of necrosis.

RESULTS

Overall, 288 patients (576 breasts) underwent inferior pedicle breast reduction from 2014 to 2019. The mean sternal notch-to-nipple (SNN) distance was 31.5 cm (standard deviation[SD]:4.2; range[r]:16-48), and the mean nipple-to-inframammary fold (N-IMF) distance was 14.8 cm (SD:4.0; r:7.5-27). The mean resection weight was 699.6 g (SD:310.4; r:125-2,385). The median follow-up was 3.9 months (interquartile range[IQR]:2.8-9.0). The overall skin or nipple areolar complex necrosis rate was 2.1%; the overall complication rate was 14.8%. On multivariate analysis, overall necrosis was not found to be associated with the N-IMF distance (adjusted odds ratio[aOR]:1.05, 95%-CI 0.88-1.16). Resection weight was statistically associated with an increased risk of overall necrosis (aOR:1.003, 95%-CI 1.001-1.005), adjusting for N-IMF and SNN distances.

CONCLUSION

Inferior pedicle breast reduction offers low risk of necrosis and can be safely performed in patients regardless of the N-IMF distance. No association was found between N-IMF distance and overall necrosis in our cohort, including lengths >15 cm. However, large resections could increase the risk of necrosis.

Efficacy of a Urinary Bladder Matrix for Treating Wound Dehiscence With Hardware Exposure in a Patient With Rheumatoid Arthritis

OBJECTIVE

This case report explores an effective treatment modality in a medically complicated patient, with considerable wound dehiscence refractory to treatment with negative pressure wound therapy (NPWT).

CASE REPORT

A 35-year-old woman with a past medical history of hypothyroidism, osteoporosis, and rheumatoid arthritis treated with tumor necrosis factor (TNF) alpha inhibitors and disease-modifying antirheumatic drugs presented to the clinic following right great toe arthrodesis, metatarsal neck osteotomies, extensor tendon lengthening, and capsulotomy of the second, third, fourth, and fifth toes 2 weeks prior, with wound dehiscence of the right great toe and subsequent exposure of surgical hardware, complicated by infection. At the 2-week postop, a urinary bladder matrix was placed on the wound following failed NPWT, which was in place for 10 days. At the 3-month follow-up, the wound was closed and without any drainage. Patient reported a significant reduction in pain (visual analogue scale: 3) with adherence to weight-bearing restrictions.

CONCLUSIONS

Wound healing was accomplished without removal of the exposed deep hardware in a patient with comorbidities and post-surgical wound dehiscence.

Comparison of two methods for coracoclavicular ligament reconstruction: A finite element analysis

OBJECTIVE

This study aimed to compare two different tendon grafting techniques for coracoclavicular ligament reconstruction from the data obtained using finite element analysis.

METHODS

Three different finite element models of the shoulder girdle were formulated using computerized tomography images: the reference model, coracoid loop technique (CLT), and drilling technique (DT) model. In all these models, forces were applied to the clavicle along three axes (x, y, and z) of the trapezius and sternocleidomastoid muscles. Thereafter, data regarding the loading values of the tendon grafts, loads on the coracoid base, and coracoclavicular vertical distance were measured.

RESULTS

While the reference model yielded the lowest values for all the loading conditions as well as the shortest coracoclavicular distance, the DT model demonstrated the highest values for all the loading conditions and the largest coracoclavicular distance.

CONCLUSION

Different tendon grafting techniques may offer different loading values on both bone surface and tendon graft during coracoclavicular ligament reconstruction. The drilling technique may be associated with increased loading on the tendon graft and bone surface, causing further loss of reduction and consequent complications.

Effects of SCCO2, Gamma Irradiation, and Sodium Dodecyl Sulfate Treatments on the Initial Properties of Tendon Allografts

Sterile and decellularized allograft tendons are viable biomaterials used in reconstructive surgeries for dense connective tissue injuries. Established allograft processing techniques including gamma irradiation and sodium dodecyl sulfate (SDS) can affect tissue integrity. Supercritical carbon dioxide (SCCO₂) represents a novel alternative that has the potential to decellularize and sterilize tendons with minimized exposure to denaturants, shortened treatment time, lack of toxic residues, and superior tissue penetration, and thus efficacy. This study attempted to develop a single-step hybrid decellularization and sterilization protocol for tendons that involved SCCO₂ treatment with various chemical additives. The processed tendons were evaluated with mechanical testing, histology, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. Uniaxial mechanical testing showed that tendons treated with SCCO₂ and additive NovaKill^TM Gen2 and 0.1% SDS had significantly higher (p < 0.05) ultimate tensile stress (UTS) and Young's modulus compared to gamma-irradiated and standard-SDS-treated tendons. This was corroborated by the ultrastructural intactness of SCCO₂-treated tendons as examined by SEM and FTIR spectroscopy, which was not preserved in gamma-irradiated and standard SDS-treated tendons. However, complete decellularization was not achieved by the experimented SCCO₂-SDS protocols used in this study. The present study therefore serves as a concrete starting point for development of an SCCO₂-based combined sterilization and decellularization protocol for allograft tendons, where additive choice is to be optimized.

A Novel Technique of Asian Tip Plasty: Rein-Shaped Columellar Strut Graft

BACKGROUND

The columellar strut graft is one of the most commonly used invisible grafts in tip plasty techniques for nasal tip projection. However, the columellar strut graft induces cephalic rotation of the dome with nasal tip projection. This is an effective change in Western people with a long nose; however, this change should be avoided in Asians who have a relatively short nose and visible nostrils. We designed a more convenient and effective technique using a rein-shaped columellar strut graft that can prevent cephalic rotation of the dome.

METHODS

A total of 32 patients underwent surgery with a rein-shaped columellar strut graft with a septal cartilage. The projection and location of the nasal tip, nasal length, and nasolabial angle were measured after taking a photograph of the lateral view, and the preoperative and postoperative results were compared.

RESULTS

There were statistically significant differences between the preoperative and postoperative values of the nasal tip projection ratio and nasal tip location ratio. There were no revision surgeries and no direct complications associated with the use of the columellar strut graft.

CONCLUSION

We performed tip plasty with a modified columellar strut graft-the rein-shaped columellar strut graft. In most cases of using this method, the tip projection was increased and the cephalic rotation of the tip was prevented. This surgical procedure can also be used for lengthening (rotating caudally) of the nose in some cases, as well as for the purpose of preventing the cephalic rotation of the tip.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Histological evaluation of subepithelial connective tissue grafts harvested by two different techniques: Preliminary study in humans

Subepithelial connective tissue graft (SCTG) is an essential therapeutic tool in periodontal plastic surgery and implantology. The aim of this preliminary study was to observe and make a histological and histomorphometric comparison of the composition of subepithelial connective tissue grafts (SCTGs) harvested from the palatal mucosa by two different harvesting techniques: mucoperiosteal (lamina propria and complete submucosa including periosteum) and mucosal (lamina propria and a portion of the submucosa). The main hypothesis proposes that SCTG harvested with the mucosal technique contains a greater proportion of connective tissue proper (CTP) and a lower proportion of adipose tissue (AT) than the mucoperiosteal technique. Twenty healthy patients who required SCTG for different purposes were selected and assigned to one of the two following groups: group A (n=10; mucoperiosteal harvesting technique) and group B (n=10, mucosal harvesting technique). The histological sample was obtained by removing a 2 mm thick slice from the most distal portion of the graft. The proportions of adipose tissue (AT), connective tissue proper (CTP) and vascular tissue (VT) were evaluated. In group A, histomorphometric analysis showed that CTP accounted for 58.2% of the graft while AT accounted for 32.64%. In group B, the proportions of CTP and AT were 79.86% and 11.93%, respectively. The differences between groups were statistically significant for both tissues (p< .05). In contrast, no statistically significant difference was observed in the proportion of VT. Within the limitations of this study, the results show that the SCTGs harvested by the mucosal technique contain a greater proportion of CTP and a lower proportion of AT than those obtained by the mucoperiosteal technique, whereas the proportion of VT does not differ. Further long-term clinical and histological studies with more samples are needed to evaluate the clinical implications of SCTG composition.

Fat Grafting for Improved Ileostomy Ostomy Device Fit: A Case Report

For patients with an ostomy, a poor fitting appliance may cause leakage, peristomal dermatitis, and frequent appliance changes.

PURPOSE

The purpose of this case study was to report the outcome of fat grafting to augment peristomal soft tissue and improve appliance fit.

CASE STUDY

A 57-year-old woman with a history of Crohn's disease presented with soft-tissue deficiency and uneven contour around her ileostomy site. She was unable to properly fit an ostomy appliance, which resulted in leakage, chronic skin irritation, and frequent appliance changes. The patient underwent 2 rounds of fat grafting using fat harvested from her medial thighs and knees infused with dilute lidocaine with epinephrine. The patient noted immediate improvement after 34 cc of processed fat was injected in the first round. Appliance change frequency decreased from daily to every 3 to 4 days. A second graft of 32 cc provided 3 months later further improved appliance fit, reducing appliance change frequency to every 5 to 7 days and obviating the need to use adjustment rings and glue. Pre- and postoperative computed tomography showed increased thickness of abdominal wall subcutaneous tissues.

CONCLUSION

Fat grafting around an ostomy site presents a viable option to improve contour and appliance fit with reduced skin irritation and leakage.

A simplified soft tissue management for peri-implant bone augmentation

PURPOSE

This case series illustrates a simplified soft tissue management, namely, the subperiosteal peri-implant augmented layer (SPAL), to increase hard and soft tissue dimensions at the most coronal portion of an implant.

MATERIALS AND METHODS

Twenty-seven implants in 16 patients presenting either a buccal bone dehiscence or a thin (< 1 mm) buccal cortical bone plate (BCBP) were consecutively treated. Briefly, a split-thickness flap (namely, the mucosal layer) was raised on the buccal aspect. Then, the periosteal layer was elevated from the bone crest. A full-thickness flap was elevated on the oral aspect. After implant site preparation, a xenograft was used to fill the space between the periosteal layer and the BCBP and/or exposed implant surface and, if present, to completely correct the bone dehiscence. The periosteal layer was sutured to the oral flap. The mucosal layer was coronally advanced and sutured to submerge both the graft and the implants. At 3 to 6 months, a re-entry procedure for implant exposure was performed.

RESULTS

Healing was uneventful, with no signs of infection in all cases. A wound dehiscence was observed in three implants in two patients at 2 weeks postsurgery. Out of 15 implants showing an initial bone dehiscence, 12 implants (80%) showed a complete resolution, with a subperiosteal tissue thickness (SPTT) at the time of re-entry of 3.1 ± 1.0 mm. Three implants presented a residual dehiscence of 1 mm (two implants) or 2 mm (one implant), with a SPTT of at least 2 mm. Out of 12 implants showing a thin BCBP at implant placement, 10 implants (90%) revealed a SPTT ≥ 2 at the time of re-entry. Two implants revealed a SPTT of 1 mm.

CONCLUSION

The SPAL technique represents a valuable simplified surgical approach associated with a low rate of complications in the treatment of peri-implant bone dehiscence and in the horizontal augmentation of peri-implant tissue thickness.

Plasma rich in growth factors membrane as coadjuvant treatment in the surgery of ocular surface disorders

To evaluate the safety and efficacy of the surgical use of plasma rich in growth factors fibrin membrane (mPRGF) in different ocular surface pathologies.Fifteen patients with different corneal and conjunctival diseases were included in the study. Patients were grouped according to the use of mPRGF as graft (corneal and/or conjunctival) or dressing; they were also grouped according to the surgical subgroup of intervention (persistent corneal ulcer [PCU], keratoplasty, superficial keratectomy, corneal perforation, and pterygium). Best corrected visual acuity, intraocular pressure (IOP), inflammation control time (ICT), mPRGF AT (PRGF membrane absorption time), and the healing time of the epithelial defect (HTED) were evaluated throughout the clinical follow-up time. Safety assessment was also performed reporting all adverse events.mPRGF showed a total closure of the defect in 13 of 15 patients (86.7%) and a partial closure in 2 patients (13.3%). The mean follow-up time was 11.1 ± 4.2 (4.8-22.8) months, the mean ICT was 2.5 ± 1.1 (1.0-4.0) months, the mean mPRGF AT was 12.4 ± 2.0 (10.0-16.0) days, and for the global HTED the mean was 2.9 ± 1.2 (1-4.8) months. Results showed an improvement in BCVA in all patients, with an overall improvement of 2.9 in Vision Lines. The BCVA significantly improved (P < .05) in the groups of corneal graft and dressing. In the PCU subgroup (6 patients), the healing time of epithelial defect was significantly reduced (P < .05) in patients treated only with the mPRGF in comparison to those which mPRGF therapy was associated to the amniotic membrane. The IOP remained stable (P > .05) throughout the clinical follow-up time. No adverse events were reported after mPRGF use.The mPRGF is effective and safe as coadjuvant treatment in surgeries related with ocular surface disorders, being an alternative to the use of amniotic membrane. The mPRGF accelerates tissue regeneration after ocular surface surgery thus minimizing inflammation and fibrosis.

Preservation of Natural Gingival Pigmentation When Treating Multiple Gingival Recession Defects

Proper surgical techniques can permit treatment of multiple gingival recession defects without altering the visible gingival pigmentation. In this case report, a patient presented with multiple adjacent sites displaying gingival recession. Natural pigmentation was present in the interdental papillae and in the zone of keratinized gingiva. This patient wanted his natural pigmentation to be preserved. A modified tunnel technique was used to avoid traumatizing the pigmented tissues and allow placement of a large graft. A double layer of an acellular dermal matrix (ADM) was implanted and the gingival complex was relocated coronally. Root coverage and preservation of the natural gingival pigmentation were achieved. The use of the modified tunnel technique with a double layer of ADM can preserve natural gingival pigmentation when treating adjacent gingival recession defects.

Rotator cuff tendon-to-bone healing at 12 months after patch grafting of acellular dermal matrix in an animal model

There is no report to investigate the histology and biomechanical strength of remodeled tendon-to-bone junction more than 6 months after patch grafting with acellular dermal matrix (ADM) on rotator cuff defect. We investigated those 12 months after surgery and hypothesized that a new native enthesis is not regenerated and the biomechanical strength is inferior to normal control. Adult male Sprague-Dawley rats underwent ADM patch grafting for the rotator cuff defect. Quantitative histological analysis, immunohistochemical analysis for collagen type I and III, and biomechanical testing were performed 12 months after surgery. The controls were unoperated age-matched rats. In the grafted rats, the collagen arrangement was more irregular and the fibrocartilage layer was smaller at the tendon-bone interface than in the controls although dense collagen fibers in the remodeled tendon were observed; the number of chondrocytes, the percentage of chondrocytes aligned in rows, and the area of the fibrocartilage layer were significantly smaller than in the control group (p = 0.0252, 0.0039, and 0.0252, respectively). Grafted specimens showed significantly lower collagen organization in the midsubstance and tendon-bone interface than the controls (p = 0.0252 and 0.0374, respectively). Immunohistochemical analysis demonstrated that the remodeled tendon fibers were stained more strongly for type III than type I. At 12 months postoperatively, the ultimate load to failure was significantly lower in the graft group than normal control (p = 0.0026); that was 47.8% of normal controls. 12 months after rotator cuff patch grafting with ADM, the formation of a new enthesis grossly resembled the native structure but there was poor cellular organization and the biomechanical strength of remodeled tendon-to-bone was only 48% of normal controls. Advances in tissue engineering and postoperative rehabilitation are needed to promote the healing process after rotator cuff patch grafting.

Tissue Transplantations in Planarians

Tissue transplantation is an important tool for in vivo studies of pattern organization and axis establishment or maintenance in planarians. Further, transplants can inform on cell movements under different regenerative conditions or genetic backgrounds. Here, we detail classical grafting strategies that have been variously employed in planarian research over the last few decades. These protocols remain similarly useful for addressing current and future questions in the field and the step-by-step protocol that we provide allows facile adaptation of this important method into the experimental repertoire of a laboratory.

Osseous-Cartilaginous Spreader Graft and Nasal Framework Reconstruction

Revision rhinoplasties and saddle nose deformities usually require grafting for reconstruction. Between January 1, 2000, and January 1, 2017, autologous rib grafts were used in 127 secondary and tertiary rhinoplasty patients [(57/127 females) and (70/127 males)]. Osseous-cartilaginous rib grafts (OCRGs) were divided into three parts (i.e., 1/3 upper peripheral, 1/3 central, and 1/3 lower peripheral). The harvested OCRGs were also shaped as vertical strips using a number 11 scalpel blade. These OCRGs were shaped to form the L-strut cartilaginous graft (LSCGs), osseous-cartilaginous spreader grafts (OCSGs), osseous-cartilaginous onlay grafts, nasal valve grafts (NVGs), and lower lateral cartilaginous grafts (LLCGs). The upper peripheral portion of the rib was usually used as an onlay graft for dorsal reshaping. The shape of this part was minimally convex after being cut from the main graft, and the convex shape was very appropriate for use as an onlay graft. The middle portion of the graft that consisted of the osseous and cartilaginous structure was used for the OCSGs. The middle portion of the graft that contained only cartilage was used for the LSCGs, NVGs, and LLCGs. OCRGs were used for the dorsal, alar, septal, upper lateral, and columellar struts for all patients. OCSGs were used for all of the septal grafts to provide further stability. In the nasal valve failure patients, the rib cartilage was fixed onto the lower lateral and upper lateral cartilage and was sutured using polyglactin to improve nasal valve function. One edge of the graft was sutured over the septum, and the other edge was positioned against the maxillary crest to allow for air flow at the nasal valve. After an OCSG was sutured to the septum, a flat and smooth dorsum was shaped before the dorsal onlay graft was placed and fixed. The bone fragments of the grafts that consisted of spreader and onlay grafts were tied to the radix nasi bone without any space. After 6 months of follow-up, a minimally warping defect was apparent in 8 patients but none of these patients requested another surgery. The analysis of the questionnaire responses revealed that >90% of the patients were satisfied with the outcome of the procedure. Level of evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Grafts in Glaucoma Surgery: A Review of the Literature

Patients with bleb leakage, dehiscence, or infection after trabeculectomy need urgent bleb salvaging to prevent vision loss. Patients who have undergone a glaucoma drainage device surgery may have tube erosion, which is yet another devastating and outcome-compromising complication. The bleb or the tube in such cases needs to be patched by a biologic tissue, which is roofed by the conjunctiva and acts as a barrier against external infections. Sclera, pericardium, cornea, and dura mater are the commonly used patch graft materials. This review reports the outcomes of several new and old graft materials used to repair the post trabeculectomy compromised bleb and tube exposure in glaucoma drainage device surgeries.

Restorative Tissue Transplantation Options for Osteochondral Lesions of the Talus: A Review

Symptomatic osteochondral lesions of the talus remain a challenging problem due to inability for cartilage lesions to heal. Numerous treatment options exist, including nonoperative management, marrow stimulating techniques, and autograft-allograft. Arthroscopic marrow stimulation forms fibrocartilage that has been shown to be biomechanically weaker than hyaline cartilage. Restorative tissue transplantation options are being used more for larger and cystic lesions. Newer biologics and particulated juvenile cartilage are currently under investigation for possible clinical efficacy. This article provides an evidenced-based summary of available literature on the use of biologics for treatment of osteochondral lesions of the talus.

Autologous minced muscle grafts improve endogenous fracture healing and muscle strength after musculoskeletal trauma

The deleterious impact of concomitant muscle injury on fracture healing and limb function is commonly considered part of the natural sequela of orthopedic trauma. Recent reports suggest that heightened inflammation in the surrounding traumatized musculature is a primary determinant of fracture healing. Relatedly, there are emerging potential therapeutic approaches for severe muscle trauma (e.g., volumetric muscle loss [VML] injury), such as autologous minced muscle grafts (1 mm3 pieces of muscle; GRAFT), that can partially prevent chronic functional deficits and appear to have an immunomodulatory effect within VML injured muscle. The primary goal of this study was to determine if repair of VML injury with GRAFT rescues impaired fracture healing and improves the strength of the traumatized muscle in a male Lewis rat model of tibia open fracture. The most salient findings of the study were: (1) tibialis anterior (TA) muscle repair with GRAFT improved endogenous healing of fractured tibia and improved the functional outcome of muscle regeneration; (2) GRAFT repair attenuated the monocyte/macrophage (CD45+CDllb+) and T lymphocyte (CD3+) response to VML injury; (3) TA muscle protein concentrations of MCP1, IL-10, and IGF-1 were augmented in a proregenerative manner by GRAFT repair; (4) VML injury concomitant with osteotomy induced a heightened systemic presence of alarmins (e.g., soluble RAGE) and leukocytes (e.g., monocytes), and depressed IGF-1 concentration, which GRAFT repair ameliorated. Collectively, these data indicate that repair of VML injury with a regenerative therapy can modulate the inflammatory and regenerative phenotype of the treated muscle and in association improve musculoskeletal healing.

Growth of Murine Splenic Tissue Is Suppressed by Lymphotoxin β-Receptor Signaling (LTβR) Originating from Splenic and Non-Splenic Tissues

Development and maintenance of secondary lymphoid organs such as lymph nodes and spleen essentially depend on lymphotoxin β-receptor (LTβR) signaling. It is unclear, however, by which molecular mechanism their size is limited. Here, we investigate whether the LTβR pathway is also growth suppressing. By using splenic tissue transplantation it is possible to analyze a potential contribution of LTβR signaling inside and outside of the implanted tissue. We show that LTβR signaling within the endogenous spleen and within non-splenic tissues both significantly suppressed the regeneration of implanted splenic tissue. The suppressive activity positively correlated with the total number of LTβR expressing cells in the animal (regenerate weights of 115 ± 8 mg in LTβR deficient recipients and of 12 ± 9 mg in wild-type recipients), affected also developed splenic tissue, and was induced but not executed via LTβR signaling. Two-dimensional differential gel electrophoresis and subsequent mass spectrometry of stromal splenic tissue was applied to screen for potential factors mediating the LTβR dependent suppressive activity. Thus, LTβR dependent growth suppression is involved in regulating the size of secondary lymphoid organs, and might be therapeutically used to eradicate tertiary lymphoid tissues during autoimmune diseases.

Bicentric prospective evaluation of corporoplasty with porcine small intestinal submucosa (SIS) in patients with severe Peyronie's disease

INTRODUCTION

Advanced Peyronie's disease (PD) with severe penile deviation demands grafting procedures following plaque incision or partial plaque excision in order to avoid penile shortening and to improve quality of life of affected patients. Small intestinal submucosa (SIS) is an established xenograft. The objective of the present study was to validate external results in a bicentric prospective manner.

METHODS

Patient selection criteria, surgical technique and standards for pre- and postoperative care were defined. Consecutively, patients with severe penile deviation in stable disease and sufficient erectile function were included between 2007 and 2015. After plaque incision, grafting was performed using SIS in a standardized manner. The postoperative evaluation using a non-validated questionnaire included complications, correction of curvature, pre- and postoperative erectile function, change in penile length and general satisfaction with the procedure.

RESULTS

Forty-three patients underwent surgery between 2007 and 2015. The mean degree of preoperative curvature was 73.8° (range 60-90°). No intraoperative or major postoperative complications were reported. After a mean follow-up of 33.0 months (range 10-59), complete straightening of the penis was achieved in 74.4%. 88.4% of all patients were able to achieve satisfying sexual intercourse (67.4% unaided, 21.0% with assistance). The IIEF-5 score was improved in 69.8% (mean improvement 4.0 points). Overall 86.0% were satisfied with the surgical treatment.

CONCLUSION

Corporoplasty with SIS in patients with PD and severe penile curvature is a safe approach and shows good long-term results. A thorough patient selection and a standardized pre-, intra- and postoperative procedure are decisive for a satisfying outcome.

The versatile subepithelial connective tissue graft: a literature update

Harmony between hard and soft tissue morphologies is essential for form, function, and a good esthetic outlook. Replacement grafts for correction of soft tissue defects around the teeth have become important to periodontal plastic and implant surgical procedures. Among a multitude of surgical techniques and graft materials reported in literature, the subepithelial connective tissue graft (SCTG) has gained wide popularity and acceptance. The purpose of this article is to acquaint clinicians with the current understanding of the versatile SCTG. Key factors associated with graft harvesting as well as applications, limitations, and complications of SCTGs are discussed. This connective tissue has shown excellent short- and long-term stability, is easily available, and is economical to use. The SCTG should be considered as an alternative in all periodontal reconstruction surgeries.

Use of Double Layer of Acellular Dermal Matrix and Modified Tunnel Technique to Treat Multiple Adjacent Gingival Recession Defects

The goal of connective tissue grafting is to cover exposed root surfaces with gingival tissues that are stable and have a natural appearance. The use of an acellular dermal matrix (ADM) has been shown to be a successful alternative to the palatal connective tissue graft. Use of a double layer of an ADM has been shown to have stable results for 1 year. Tunnel grafting techniques can yield root coverage with a natural appearing soft-tissue architecture. The purpose of this case report is to demonstrate the use of a modified tunnel technique and a double layer of ADM in the treatment of multiple adjacent gingival recession defects. Treated teeth were found to have root coverage and natural soft-tissue contours that were stable at 20 months.

Restoration of ovarian tissue function and estrous cycle in rat after autotransplantation using hyaluronic acid hydrogel scaffold containing VEGF and bFGF

This study investigates the effect of hyaluronic acid (HA) containing VEGF and bFGF on restoration of ovarian function after ovarian autotransplantation. Twenty-four rats were randomly divided into three groups for ovarian autotransplantation: group A (ovaries without HA, VEGF and bFGF), group B (ovaries encapsulated with HA) and group C (ovaries encapsulated with HA containing VEGF and bFGF). The grafts were assessed using vaginal smears, histological, hormonal, and the genes expression analysis. The duration of first estrous cycle was shorter in group C than in group A (p < 0.01). The mean number of primordial follicles was protected in group C. The level of estradiol was higher in group A than in group C (p < 0.01). The expression level of Cellular-Myelocytomatosis (C-Myc) in group C was lower than in group B (p < 0.05). HA containing VEGF and bFGF can ensure follicular survival, decrease apoptosis and recover ovarian function after auto-transplantation.

Matrix scaffolding for stem cell guidance toward skeletal muscle tissue engineering

Extracellular matrix (ECM) is composed of many types of fibrous structural proteins and glycosaminoglycans. This important cell component not only provides a support for cells but is also actively involved in cell-cell interaction, proliferation, migration, and differentiation, representing, therefore, no longer only a mere static structural scaffold for cells but rather a dynamic and versatile compartment. This aspect leads to the need for investigating new bio-inspired scaffolds or biomaterials, able to mimic ECM in tissue engineering. This new field of research finds particular employment in skeletal muscle tissue regeneration, due to the inability of this complex tissue to recover volumetric muscle loss (VML), after severe injury. Usually, this is the result of traumatic incidents, tumor ablations, or pathological states that lead to the destruction of a large amount of tissue, including connective tissue and basement membrane. Therefore, skeletal muscle tissue engineering represents a valid alternative to overcome this problem.Here, we described a series of natural and synthetic biomaterials employed as ECM mimics for their ability to recreate the correct muscle stem cell niche, by promoting myogenic stem cell differentiation and so, positively affecting muscle repair.

Lamina Propria Replacement Therapy with Cultured Autologous Fibroblasts for Vocal Fold Scars

OBJECTIVES: To develop a canine model of vocal fold scar and to evaluate its treatment with lamina propria replacement therapy using autologous cultured fibroblasts.

MATERIALS AND METHODS: Full thickness of the lamina propria layer in canine vocal folds was injured with a laser. Fibroblasts were cultured and expanded in the laboratory from a buccal mucosal biopsy. The scarred vocal folds were treated with 3 weekly injections of fourth, fifth, and sixth passage autologous fibroblasts. Mucosal waves and acoustic parameters were measured at baseline, after scarification, and several months after injection therapy. Histologic evaluation of the vocal folds for fibroblasts, collagen, elastin, reticulin, and hyaluronic acid was performed.

RESULTS: Nine beagle dogs were used, and 1 animal served as control. Vocal fold scarring resulted in absent or severely limited mucosal waves and significantly worse acoustic parameters. Significant improvements in mucosal waves and acoustic parameters were obtained after lamina propria replacement therapy. After therapy, mucosal waves became normal in 4 animals and near normal in the other 4. No statistical difference was found in mucosal waves between baseline and post-therapy. All animals tolerated therapy without complications. The treated vocal folds demonstrated an increased density of fibroblasts, collagen, and reticulin, a decreased density of elastin, and no change in hyaluronic acid.

CONCLUSIONS AND SIGNIFICANCE: Therapeutic options for vocal fold scars are limited. Lamina propria replacement therapy in the form of autologous cultured fibroblasts improves mucosal pliability and returns normal or near normal mucosal waves in experimentally scarred vocal folds. This novel therapeutic modality may hold new promise for treating vocal fold scars.

Concerns on Clinical Application of Composite Tissue Allotransplantation

Composite tissue allograft has become a clinical reality: hands, vascularized femoral diaphyses, abdominal walls, a larynx have all been transplanted throughout the world. Conventional immunosuppressive protocol has shown to be sufficient and effective. Rejection has been prevented in most cases and when it did occur it was successfully reversed. Skin has been confirmed as the principal target of acute and chronic rejection. There has been no mortality or early graft losses and, particularly in hand transplantation, the survival graft rate is 91% with a follow-up period ranging from 6 months to 61 months. The side effects of immunosuppression are limited and include primarily transient hyperglycemia, an increase in creatinine values and some opportunistic infections (i.e. cytomegalovirus infection). Nerve regeneration and cortical reorganization have been demonstrated in hand transplantation. Functional results have been encouraging particularly for hand and larynx transplantation. Appropriate indications and patient selection, based particularly on patient motivation and compliance, are essential requirements for composite tissue allograft success.

Outcome of amniotic membrane as an interpositional arthroplasty of TMJ ankylosis

PURPOSE

Temporomandibular joint ankylosis is a major disorder, mainly due to trauma and other reasons, which is responsible for the restriction of mandibular functional activities. The scope of the successful surgical correction of temporomandibular joint ankylosis with amniotic membrane is on the membrane's being an interpositional material which we found not to elicit any host reaction, is capable of functional adaptation, and is very economical. Our purpose is to show the amniotic membrane as a suitable, biocompatible, and interpositional material alternative to the other materials, thereby reducing donor site morbidity.

METHODS

A study was conducted in 13 patients with an age range of 10 to 35 years with unilateral and bilateral bony TMJ ankylosis confirmed by clinical and radiological evaluations. Preoperative and postoperative clinical assessments of TMJ functions were done. Amniotic membranes were collected from the tissue bank, sterilized by gamma radiation, and freeze-dried. Then, the prepared amniotic cap (10-15 layers of amniotic membrane) was placed over the condylar head and anchored loosely to the neck and the surrounding tissues with a 3/0 Vicryl suture.

RESULTS

Measurements of postoperative maximum interincisal opening was taken with scale among the 13 patients. Preoperative interincisal distances ranged from 0 to 15 mm, and preoperative and immediate postoperative were 33-45 and 25-32 mm, respectively. Postoperative follow-up of interincisal opening after 1-, 6-, and 12-month intervals was found from 32 to 35 mm. Lateral excursions (left and right), protrusive movements, and functional recovery were all satisfactory.

CONCLUSION

Amniotic membrane graft as an interpositional material in temporomandibular joint ankylosis can be a good alternative as to prevent reankylosis and recover functionality.

Regeneration of Vocal Fold Mucosa Using Tissue-Engineered Structures with Oral Mucosal Cells

OBJECTIVES

Scarred vocal folds result in irregular vibrations during phonation due to stiffness of the vocal fold mucosa. To date, a completely satisfactory corrective procedure has yet to be achieved. We hypothesize that a potential treatment option for this disease is to replace scarred vocal folds with organotypic mucosa. The purpose of this study is to regenerate vocal fold mucosa using a tissue-engineered structure with autologous oral mucosal cells.

STUDY DESIGN

Animal experiment using eight beagles (including three controls).

METHODS

A 3 mm by 3 mm specimen of canine oral mucosa was surgically excised and divided into epithelial and subepithelial tissues. Epithelial cells and fibroblasts were isolated and cultured separately. The proliferated epithelial cells were co-cultured on oriented collagen gels containing the proliferated fibroblasts for an additional two weeks. The organotypic cultured tissues were transplanted to the mucosa-deficient vocal folds. Two months after transplantation, vocal fold vibrations and morphological characteristics were observed.

RESULTS

A tissue-engineered vocal fold mucosa, consisting of stratified epithelium and lamina propria, was successfully fabricated to closely resemble the normal layered vocal fold mucosa. Laryngeal stroboscopy revealed regular but slightly small mucosal waves at the transplanted site. Immunohistochemically, stratified epithelium expressed cytokeratin, and the distributed cells in the lamina propria expressed vimentin. Elastic Van Gieson staining revealed a decreased number of elastic fibers in the lamina propria of the transplanted site.

CONCLUSION

The fabricated mucosa with autologous oral mucosal cells successfully restored the vocal fold mucosa. This reconstruction technique could offer substantial clinical advantages for treating intractable diseases such as scarring of the vocal folds.

Danish experience with free flaps in war wounds

INTRODUCTION

To describe the lessons learned from treatment of war casualties at a public hospital in Denmark.

METHODS

A retrospective review of soldiers who underwent free flap reconstruction at Rigshospitalet, Denmark, between January 2006 and December 2010.

RESULTS

Nine patients were treated using free flaps. The age distribution was 21-34 years. Extremity fractures associated with considerable soft tissue loss were seen in all cases. The mean time from injury to reconstruction was 13.2 days. A total of 11 free flaps were used, the majority of which were latissimus dorsi flaps (seven out of 11). Flap-loss occurred in one patient, presumably due to leakage at the anastomotic site, which necessitated another free flap procedure. All patients received rehabilitation services following discharge from the inpatient unit, including prosthetic fitting. The mean follow-up time was 26 months.

CONCLUSIONS

This report is the first to detail the reconstructive procedures in soldiers treated at a public hospital in Denmark. The treatment of war casualties has not only been a challenge to the surgeons tasked with managing these devastating injuries, but also to Danish healthcare in general. The outcome of multidisciplinary treatment, combining the expertise of various specialties, is highly encouraging. The rate of complications was low, and the aesthetic appearance of the reconstructed limbs and the functional recovery were satisfactory. We therefore recommend the use of free flaps to reconstruct defects resulting from battlefield trauma.

FUNDING

none.

TRIAL REGISTRATION

not relevant.

Effect of repeated subcutaneous injections of carbon dioxide (CO2) on inflammation linked to hypoxia in adipose tissue graft

OBJECTIVE

The purposes of this study was to assess the effect of repeated subcutaneous injections of CO2 on adipose tissue graft survival in immunosuppressed female nude mice. The authors designed an experimental study using volume measures, histopathological analysis and nuclear magnetic resonance of fat graft. The effect of repeated subcutaneous injection of CO2 is not yet investigated

MATERIALS AND METHODS

Approximately 0.5 ml of human fat were transplanted in a group of female nude mice. The mice were treated with 3 injections of 80 µl each carbon dioxide (total 240 µl) for 7 weeks. Initially, in vivo measurements were conducted and subsequently a comprehensive histopathological analysis was performed.

RESULTS

The presence of inflammation was graded absent to minimal in animals treated with CO2 while a minimal to moderate grade was assigned to the control group.

CONCLUSIONS

CO2 injection enhances the inflammatory response of the implanted tissue and reduces the reabsorption rate. The treatment may improve the graft survival in a more prolonged time-frame.

Postextraction Socket Seal Surgery with an Epithelized Connective Tissue Graft Using a Subpapillar Tunneling Procedure

Ridge preservation in the esthetic area is still a challenging procedure. The aim of the present case series was to introduce a technique for postextraction socket seal surgery using an epithelized connective tissue graft and socket filling with a xenogeneic biomaterial. Using a tunneling approach, the buccal gingiva and interdental papillae are undermined and augmented with the soft tissue graft. This method was applied and evaluated in 16 sites in 13 patients with need for extraction of at least one maxillary anterior tooth. Five months postoperative, the mean reduction of the horizontal width of the alveolar ridge was 0.5 mm, while the height of the mesial and distal papillae were reduced by 0.2 mm and 0.4 mm, respectively. The buccogingival margin of the alveolar ridge showed a vertical gain of 0.5 mm. Therefore, the presented technique seems appropriate for preservation of the alveolar ridge in esthetically relevant areas.

Time Course of Cell Sheet Adhesion to Porcine Heart Tissue after Transplantation

Multilayered cell sheets have been produced from bone marrow-derived mesenchymal stem cells (MSCs) for investigating their adhesion properties onto native porcine heart tissue. Once MSCs reached confluence after a 7-day culture on a temperature-responsive culture dish, a MSCs monolayer spontaneously detached itself from the dish, when the culture temperature was reduced from 37 to 20°C. The basal extracellular matrix (ECM) proteins of the single cell sheet are preserved, because this technique requires no proteolytic enzymes for harvesting cell sheet, which become a basic building block for assembling a multilayer cell sheet. The thickness of multilayered cell sheets made from three MSC sheets was found to be approximately 60 μm. For investigating the adhesion properties of the basal and apical sides, the multilayered cell sheets were transplanted onto the surface of the heart's left ventricle. Multilayered cell sheets were histological investigated at 15, 30, 45 and 60 minutes after transplantation by hematoxylin eosin (HE) and azan dyes to determine required time for the adhesion of the multilayered sheets following cell-sheet transplantation. The results showed that only the basal side of multilayered cell sheets significantly enhanced the sheets adhesion onto the surface of heart 30 minutes after transplantation. This study concluded that (1) cell sheets had to be transplanted with its basal side onto the surface of heart tissue and (2) at least 30 minutes were necessary for obtaining the histological adhesion of the sheets to the heart tissue. This study provided clinical evidence and parameters for the successful application of MSC sheets to the myocardium and allowed cell sheet technology to be adapted clinical cell-therapy for myocardial diseases.

Cryopreserved Subcutaneous Adipose Tissue for Fat Graft

Cryopreservation of subcutaneous white adipose tissue (sWAT) avoids multiple surgeries in patients subjected to reconstructive procedure. Fat grafts were performed subcutaneously on 26 mice treated with fresh (13 mice) or cryopreserved (13 mice) human sWAT. Cytofluorometry for CD marker expression of stem cells, differentiation capability, and in vivo survival of fat grafts were evaluated. In vitro analysis evidenced that cryopreservation did not affect the stem potential of samples. In vivo MRI showed that grafts were well preserved in 13 mice treated with fresh sWAT, whereas in 13 animals treated with thawed fat, graft volumes were strongly reduced after 1 week. Ultrastructural studies performed both on fresh and thawed specimens demonstrated that grafts performed with thawed sWAT are able to store lipids more slowly with respect to grafts performed with fresh sWAT and adipocytes maintained a multilocular appearance. Collected data demonstrated that the protocol of cryopreservation could maintain the regenerative capability of the sWAT, but the rate of reabsorption after fat grafting is higher using cryopreserved sWAT. Maintaining the stem potential of sWAT after cryopreservation is a very important aspect for reconstructive and regenerative medicine. The employment of cryopreserved sWAT represents an interesting goal for surgeons. Surely there is the necessity to improve the protocol of cryopreservation.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Chondrogenesis of Human Adipose-Derived Stem Cells by In Vivo Co-graft with Auricular Chondrocytes from Microtia

OBJECTIVE

To evaluate the efficiency of chondrogenesis of human adipose-derived stem cells (ADSCs) induced by auricular chondrocytes from microtia via subcutaneous co-graft in nude mice.

METHODS

Human ADSCs and auricular chondrocytes were mixed at the ratio of 7:3 and suspended in 0.2 ml of Pluronic F-127 (5.0 × 10(7) cells/ml), and injected into Balb/c nude mice as the experimental group (Exp group). The same quantity of auricular chondrocytes (Ctr.1 group) or ADSCs (Ctr.2 group) in 0.2 ml of Pluronic F-127 was set as positive and negative control groups. The mixture of auricular chondrocytes (1.5 × 10(7) cells/ml) in 0.2 ml of Pluronic F-127 was set as the low concentration of chondrocyte control group (Ctr.3). At 8 weeks after grafting, the newly generated tissue pellets were isolated for morphological examination, haematoxylin and eosin staining, toluidine blue staining and safranin O staining of glycosaminoglycan (GAG), Masson's trichrome staining and immunohistochemical staining of type II collagen, and Verhoeff-iron-hematoxylin staining of elastic fibers. GAG content was determined by Alcian blue colorimetric method, and mRNA expression of type II collagen and aggrecan were examined by real-time PCR.

RESULTS

Cartilage-like tissue with a white translucent appearance and good elasticity was generated in the Exp and Ctr.1 groups. The tissue pellets in the Ctr.2 and Ctr.3 groups were much smaller than those in the Ctr.1 group. The mature cartilage lacunas could be observed in the Exp and Ctr.1 groups, while were rarely seen in the Ctr.3 group and not observed in the Ctr.2 group. The expression of cartilage-specific extracellular matrix such as type II collagen, GAG content, aggrecan, and elastic fibers in the Exp group was similar to that in the Ctr.1 group, whereas the expression of these extracellular matrix substances was significantly lower in the Ctr.2 and Ctr.3 groups (both P < 0.01).

CONCLUSION

Auricular chondrocytes from microtia can efficiently promote the chondrogenic differentiation and chondrogenesis of ADSCs by co-grafting in vivo.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Cartilage lesions of the patella: management after acute patellar dislocation

Articular cartilage injuries to the patella are frequent after patellar dislocation. The management of these acute cartilage injuries in the acute setting can be challenging. It is well documented that acute fixation is the optimal choice for treatment of osteochondral injuries. This article discusses the challenges and potential treatment options for acute chondral/osteochondral injuries to the patella after acute patellar dislocation.

Staged urethroplasty: comparison of early functional results and quality of life in mesh graft and buccal mucosa technique

INTRODUCTION

To assess bothersome results of surgery and changes in quality of life (QoL) in patients with two-staged urethral reconstruction. In patients requiring two-staged urethroplasty a functional corpus spongiosum is usually absent, and complications such as urinary dribbling, ejaculation problems and penile deviation can be expected. Data on these complications, patient satisfaction and QoL is limited.

MATERIALS AND METHODS

Retrospective analysis by chart review and a standardized questionnaire of 19 consecutive patients with urethral strictures treated by two-staged urethroplasty with buccal-mucosa-graft or mesh-graft.

RESULTS

Overall success rate was 84%. Mean follow up 11.2 months, mean length of graft 10 cm (3 cm-18 cm). Urinary stress incontinence occurred in 3 patients (16%). No penile shortening occurred in 9 (47%), no deviation in 11 (58%). Two patients (11%) reported a disturbing alteration in glans sensitivity. Regarding bother by both surgeries and the interval in between, 21% judged the first surgery as hardly or not bothersome. The time in between surgeries was hardly or not bothersome in 52% and the second surgery not or hardly bothersome in 26%. Overall satisfaction with surgery was high (79%) and an improvement in QoL was reported by 63%. Differences between the two groups did not reach statistical significance.

CONCLUSION

Two-staged urethroplasty is a viable therapeutic option in patients with severe spongiofibrosis. However, specific counseling for possible complications is of utmost importance.

A hyaluronan-based scaffold for the in vitro construction of dental pulp-like tissue

Dental pulp tissue supports the vitality of the tooth, but it is particularly vulnerable to external insults, such as mechanical trauma, chemical irritation or microbial invasion, which can lead to tissue necrosis. In the present work, we present an endodontic regeneration method based on the use of a tridimensional (3D) hyaluronan scaffold and human dental pulp stem cells (DPSCs) to produce a functional dental pulp-like tissue in vitro. An enriched population of DPSCs was seeded onto hyaluronan-based non-woven meshes in the presence of differentiation factors to induce the commitment of stem cells to neuronal, glial, endothelial and osteogenic phenotypes. In vitro experiments, among which were gene expression profiling and immunofluorescence (IF) staining, proved the commitment of DPSCs to the main components of dental pulp tissue. In particular, the hyaluronan-DPSCs construct showed a dental pulp-like morphology consisting of several specialized cells growing inside the hyaluronan fibers. Furthermore, these constructs were implanted into rat calvarial critical-size defects. Histological analyses and gene expression profiling performed on hyaluronan-DPSCs grafts showed the regeneration of osteodentin-like tissue. Altogether, these data suggest the regenerative potential of the hyaluronan-DPSC engineered tissue.

Effects of allogenic fetal pancreatic tissue transplantation on regeneration of islet cells in recipient rats with alloxan-induced diabetes mellitus

The linear parameters and number of Langerhans islets were evaluated in rats with alloxaninduced diabetes mellitus after transplantation of fetal pancreatic tissue to the anterior chamber of the eye. The islets significantly increased in size by week 3 after surgery and a trend to an increase in their number was observed.

A biomechanical characterisation of acellular porcine super flexor tendons for use in anterior cruciate ligament replacement: investigation into the effects of fat reduction and bioburden reduction bioprocesses

The decellularisation of xenogenic and allogeneic biological grafts offers a promising solution to replacement of the anterior cruciate ligament (ACL). The purpose of this investigation was to determine the biomechanical effects of additional fat reduction and bioburden reduction steps in the decellularisation of porcine super flexor tendon (pSFT). Study 1 investigated the use of acetone or chloroform-methanol as a fat reduction agent. The most effective of these was then carried forward into Study 2, which investigated the use of antibiotics or peracetic acid (PAA) as a bioburden reduction agent. Stress relaxation data was analysed using a Maxwell-Wiechert viscoelastic model and, in addition to classical material properties, the tangent modulus of the toe-region was determined from strength testing data. In both studies, the majority of decellularised groups demonstrated no statistical differences for material properties such as tensile strength and Young's modulus compared to native controls. Different trends were observed for many of the viscoelastic parameters, but also for the tangent modulus in the toe-region indicating a change in performance at low strains. The most severe deviations from the profile of the native tangent modulus were found to occur in Study 2 when PAA was used for bioburden reduction. Classic material properties (E, UTS etc.) are often used to compare the characteristics of native and decellularised tissues, however they may not highlight changes occurring in the tissues at low strains. In this study, this represented the physiological strains encountered by substitute acellular ACL grafts. Acetone was chosen as the fat reduction step whereas, antibiotics was preferable over PAA as a bioburden reduction step.

Changing the gingival color discrepancy induced by pigmented root using subepithelial connective tissue graft: a case report

Metallic alloys can suffer corrosion, and metallic posts and cores used for restorative procedures may develop a blue-gray pigmentation in root dentin, which in turn changes the color of gingival tissues. Removing posts and cores may lead to root fracture, and bleaching agents have a limited effect on staining from alloy corrosion. Surgical techniques for correcting undesirable esthetic deficiencies have been investigated in the literature. This article describes the case of a patient with gingival discoloration caused by root pigmentation in the maxillary area. A subepithelial connective graft harvested from the palate was used to treat the gingival color discrepancy.

Immunomodulation stimulates the innervation of engineered tooth organ

The sensory innervation of the dental mesenchyme is essential for tooth function and protection. Sensory innervation of the dental pulp is mediated by axons originating from the trigeminal ganglia and is strictly regulated in time. Teeth can develop from cultured re-associations between dissociated dental epithelial and mesenchymal cells from Embryonic Day 14 mouse molars, after implantation under the skin of adult ICR mice. In these conditions however, the innervation of the dental mesenchyme did not occur spontaneously. In order to go further with this question, complementary experimental approaches were designed. Cultured cell re-associations were implanted together with trigeminal ganglia for one or two weeks. Although axonal growth was regularly observed extending from the trigeminal ganglia to all around the forming teeth, the presence of axons in the dental mesenchyme was detected in less than 2.5% of samples after two weeks, demonstrating a specific impairment of their entering the dental mesenchyme. In clinical context, immunosuppressive therapy using cyclosporin A was found to accelerate the innervation of transplanted tissues. Indeed, when cultured cell re-associations and trigeminal ganglia were co-implanted in cyclosporin A-treated ICR mice, nerve fibers were detected in the dental pulp, even reaching odontoblasts after one week. However, cyclosporin A shows multiple effects, including direct ones on nerve growth. To test whether there may be a direct functional relationship between immunomodulation and innervation, cell re-associations and trigeminal ganglia were co-implanted in immunocompromised Nude mice. In these conditions as well, the innervation of the dental mesenchyme was observed already after one week of implantation, but axons reached the odontoblast layer after two weeks only. This study demonstrated that immunodepression per se does stimulate the innervation of the dental mesenchyme.