The role of bone marrow edema on osteochondral lesions of the talus.

BACKGROUND: To assess the functional and radiological outcomes after arthroscopic talus autologous matrix-induced chondrogenesis (AT-AMIC®) in 2 groups: patients with and without bone marrow edema (BME). METHODS: Thirty-seven patients of which 24 without edema (GNE) and 13 with edema (GE) were evaluated. All patients were treated with AT-AMIC® repair for symptomatic osteochondral talar lesion. Clinical and radiological parameters were evaluated with VAS score for pain, AOFAS and SF-12 at T0 (preoperatively), T1 (6 months), T2 (12 months), T3 (24 months) and MRI and CT-scan at T0, T1, T2 and T3. RESULTS: No patients were lost to the final follow-up. In both groups we found a significant difference for clinical and radiological parameters with ANOVA for repeated measures through four time points (p<0.001). In GNE, AOFAS improved significantly at each follow-up (p<0.05); while CT and MRI showed a significant reduction in lesion size between T1 and T2 and T2 and T3 (p<0.05). In GE, AOFAS improved significantly between T0 and T1 and T2 and T3 (p<0.05); lesion size, measured with CT, decreased between T1 and T2 (p<0.05), while with MRI the lesion showed a reduction at each follow-up (p<0.05). Lesion size was significantly higher both in MRI and CT in GE compared to GNE (p<0.05). In GNE no patients presented edema at T3, while in GE only 23.08% of the patients presented edema at T3. CONCLUSIONS: The study revealed that osteochondral lesions of the talus were characterized by bigger size both in MRI and CT in patients with edema. We conclude that AT-AMIC® can be considered a safe and reliable procedure that allows effective healing, regardless of edema and more than half of patients did not present edema six months after surgery.

The transpedicular surgical approach for the development of intervertebral disc targeting regenerative strategies in an ovine model.

PURPOSE: To investigate the suitability of the transpedicular approach (TPA) in a sheep model of IVD regenerative strategies METHODS: 24 IVD from four sheep were used. TPA and biopsies of the Nucleus pulposus (NP) were performed in 18 IVD (6 IVD control). Seven discographies were performed to assess the feasibility of injecting contrast agent. MRI, micro-CT scan, and histological analyses were performed and the accuracy of the TPA was evaluated. The effects on the vertebra and endplates were analyzed. RESULTS: 83% of our biopsies or injections were located in the NP. Osseous fragments in IVD were observed in 50%. We observed two cases (11%) of rostral endplate fracture and five cases (27%) of breaching of the cortical pedicle and encroachment into the spinal canal. Two cases of perivertebral venous embolism and two of backflow through the canal of the TPA inside the vertebra were noted. Significant damage occurred to the bone structure of the vertebra and to the rostral endplate on which the IVD had been inserted. CONCLUSIONS: TPA induces damage to the endplates, and it may lead to neurological impairment and leakage of injected materials into the systemic circulation. These adverse effects must be fully considered before proceeding with TPA for IVD regenerative strategies.

Oestrogen receptor alpha expression in neovaginal tissue of women following modified Abbé-McIndoe technique and in premenopausal women.

The aim of the study was to compare the expression of oestrogen receptor alpha (ERα) in neovaginal tissue of patients with vaginal agenesis following neovaginoplasty using regenerated, oxidised cellulose in premenopausal women. A prospective, observational case-control study was performed on eight patients with vaginal agenesis following modified Abbé-McIndoe neovaginoplasty and 10 control premenopausal women following benign gynaecologic surgery. 6F11 monoclonal antibody was used to determine ERα expression in the vaginal mucosa. Quantitative and qualitative evaluations were performed, respectively, in vaginal epithelium and stroma. The thickness of the vaginal epithelium was determined as the vertical distance between the basal layer cells and the apical surface of the superficial layer. The percentage of ERα-expressing cells was higher in the control group, except in the superficial zone of the epithelium. In the stromal tissue, ERα was detected in only one patient from the neovagina group compared with nine women in the control group. The neovagina group had a statistically thinner epithelium. Our study suggests that women with vaginal agenesis following modified Abbé-McIndoe neovaginoplasty using regenerated oxidised, cellulose experience relatively local hypo-oestrogenism in the first year after surgery, with repercussion in vaginal trophism.

Lymph node transfer and perinodal lymphatic growth factor treatment for lymphedema.

OBJECTIVE: Our objective was to define the optimal growth factor treatment to be used in combination with lymph node transfer to normalize lymphatic vascular anatomy. BACKGROUND: In the lymph node transfer method, lymphatic anastomoses are expected to form spontaneously. However, lymphangiogenic growth factor therapies have shown promising results in preclinical models of lymphedema. METHODS: The inguinal lymphatic vasculature of pigs was surgically destroyed around the inguinal lymph node. To enhance the regrowth of the lymphatic network in the defected area, adenoviral vascular endothelial growth factor C (VEGF-C) was administered intranodally or perinodally. Control animals received injections of saline or control vector. The lymphangiogenic effect of the growth factor therapy and any potential adverse effects associated with the 2 alternative delivery routes were examined 2 months postoperatively. RESULTS: Both routes of growth factor administration induced robust growth of lymphatic vessels and helped to preserve the structure of the transferred lymph nodes in comparison with the controls. The lymph nodes of the control treated animals regressed in size and their nodal structure was partly replaced by fibro-fatty scar tissue. Intranodally injected adenoviral VEGF-C and adenoviral vector encoding control gene LacZ induced macrophage accumulation inside the node, whereas perinodal administration of VEGF-C did not have this adverse effect. CONCLUSIONS: Lymphangiogenic growth factors improve lymphatic vessel regeneration and lymph node function after lymph node transfer. The perinodal route of delivery provides a basis for future clinical trials in lymphedema patients.

Micro-structural geometry of thin films intended for the inner lumen of nerve conduits affects nerve repair.

Damage to peripheral nerves can cause significant motor or sensory injuries. In serious cases, a nerve is sacrificed from another part of the body to repair a damaged nerve (autograft). The development of biodegradable polymer conduits may offer an alternative to autografts. This study investigated the surface topography and mechanical properties of smooth, pitted and grooved structures of ultra-thin poly (ε-caprolactone)/poly lactic acid blended, solvent-cast films. We have investigated the effect of the groove shape on cell morphology and alignment. Photolithography and dry/wet etching was used to develop patterned silicon substrates with grooves with accurate geometries (V shaped, sloped walls and square shaped). Using a neural cell line (NG108-15), in vitro experiments confirmed good cell attachment and proliferation on all the polymer scaffolds. Imaging techniques demonstrated that there was different cellular responses and morphology according to the shape of the groove. Studies showed that the geometry, particularly the angle of the slope and the space between grooves, affected cellular responses. In addition, biomechanical studies showed that the patterned films had excellent mechanical properties and were stronger than the natural nerve. The conduit tubes were made by rolling the films around a mandrel and using a thermal welding technique to join the edges. The promising biomechanical and in vitro results demonstrate that nerve cell responses are affected by the shape of longitudinal grooves, and particularly by the angle of the slope of the groove walls.

Host reaction to poly(2-hydroxyethyl methacrylate) scaffolds in a small spinal cord injury model.

Tissue engineered scaffolds and matrices have been investigated over the past decade for their potential in spinal cord repair. They provide a 3-D substrate that can be permissive for nerve regeneration yet have other roles including neuroprotection, altering the inflammatory cascade and mechanically stabilizing spinal cord tissue after injury. In this study we investigated very small lesions (approx. 0.25 µL in volume) of the dorsal column into which a phase-separated poly(2-hydroxyethyl methacrylate) hydrogel scaffold is implanted. Using fluorescent immunohistochemistry to quantify glial scarring, the poly(2-hydroxyethyl methacrylate) scaffold group showed reduced intensity compared to lesion controls for GFAP and the chondroitin sulfate proteoglycan neurocan after 6 days. However, the scaffold and tissue was also pushed dorsally after 6 days while the scaffold was not integrated into the spinal cord after 28 days. Overall, this small-lesion spinal cord injury model provided information on the host tissue reaction of a TE scaffold while reducing animal discomfort and care.

Long-term evaluation of porous PEGT/PBT implants for soft tissue augmentation.

Porous PEGT/PBT implants with different physico-chemical characteristics were evaluated to identify its potential as biodegradable and biofunctional soft tissue filler. Implants (50 x 10 x 5 mm3) were implanted subcutaneously in mini-pigs and tissue response, tissue volume generated and its consistency were assessed quantitatively with a 52 weeks follow-up. The absence of wound edema, skin irritation, and chronic inflammation demonstrated biocompatibility of all implants evaluated. The hydrophobic implants induced the mildest foreign body response, generated highest amount of connective tissue and demonstrated a decrease in copolymer MW of 34-37% compared to 90% decrease of the hydrophilic implants. The rate and extent of copolymer fragmentation seems to be the determining factor of success of soft tissue augmentation using porous PEGT/PBT copolymer implants.

Guided growth for fixed knee flexion deformity.

BACKGROUND: Fixed knee flexion deformity (FKFD) is an insidious problem that may complicate the management of patients with neuromuscular compromise due to cerebral palsy, spina bifida, arthrogryposis, and other conditions. The energy costs associated with crouch gait may become prohibitive and, with the inexorable progression of fixed knee flexion, secondary pain may ensue as a result of fragmentation of the patella and/or tibial tubercle. Concomitant or compensatory flexion deformity of the hips and lumbar lordosis may develop, along with "pseudo equinus" of the ankles. Recommended treatments for FKFD have included bracing; physical therapy; and, in recalcitrant cases, distal femoral osteotomy, posterior release, or frame distraction. However, these latter modalities are fraught with potential complications including neurovascular damage, loss of fixation, undercorrection malunion, fracture, and recurrent deformity. Considering that FKFD is often bilateral, the complication risks for a given patient are doubled. In a previous study, the senior author reported successful hemiepiphysiodesis of the distal anterior femur using staples. However, further experience has demonstrated some of the limitations of stapling including relatively slow correction and occasional hardware migration. This led to the development of a more versatile and reliable solution using a pair of anterior tension band plates. METHODS: In this retrospective clinical study, we are reporting this new technique of promoting gradual correction through guided growth of the distal femur, using a pair of anterior 8-plates. The correction is accomplished simultaneously and bilaterally, without immobilization, and may be combined with other operative procedures as indicated. We reviewed the charts, radiographs in a group of patients treated accordingly. RESULTS: In this group of 18 patients with 29 deformities, we noted correction averaging 1.3 degrees (range, 0.0 [1 patient]-4.8 degrees), with minimal complications. No inadvertent coronal plane deformities were created. Upon full correction, the plates were removed so as to avoid recurvatum. CONCLUSION: As an alternative to posterior capsulotomy or supracondylar extension osteotomy, we have found that guided growth is an effective and safe method of gradually correcting FKFD in growing children and adolescents. LEVEL OF EVIDENCE: 4 (retrospective clinical series).

Clinical and biometrical 12-month follow-up in patients after reconstruction of the sural nerve biopsy defect by the collagen-based nerve guide Neuromaix.

Many new strategies for the reconstruction of peripheral nerve injuries have been explored for their effectiveness in supporting nerve regeneration. However only a few of these materials were actually clinically evaluated and approved for human use. This open, mono-center, non-randomized clinical study summarizes the 12-month follow-up of patients receiving reconstruction of the sural nerve biopsy defect by the collagen-based nerve guide Neuromaix. Neuromaix was implanted as a micro-structured, two-component scaffold bridging 20-40 mm nerve defects after sural nerve biopsy in twenty patients (eighteen evaluated, two lost in follow-up). Safety of the material was evaluated by clinical examination of wound healing. Performance was assessed by sensory testing of modalities, pain assessment, and palpation for the Hoffmann-Tinel's sign as well as demarcating the asensitive area at each follow-up visit. Every patient demonstrated uneventful wound healing during the complete 12-month time course of the study. Two patients reported complete return of sensation, whereas eleven out of eighteen patients reported a positive Hoffmann-Tinel's sign at the lower leg with simultaneous reduction of the asensitive area by 12 months. Our data show that Neuromaix can be implanted safely in humans to bridge sural nerve gaps. No procedure-related, adverse events, or severe adverse events were reported. These first clinical data on Neuromaix provide promising perspectives for the bridging of larger nerve gaps in combined nerves, which should be investigated more through extensive, multi-center clinical trials in the near future.

Resultados estéticos en defectos nasales posquirúrgicos regenerados con fibrina autóloga rica en plaquetas y leucocitos / Aesthetic results in post-surgical nasal defects regenerated with autologous platelet- and leukocyte-rich fibrin

Introducción: En la reconstrucción de los defectos cutáneos nasales se han utilizado varias técnicas a nivel mundial. Novedosas prácticas utilizan los concentrados plaquetarios por sus propiedades moduladoras y favorecedoras de la regeneración tisular. Objetivo: Determinar los resultados estéticos asociados al uso de la membrana de fibrina autóloga rica en plaquetas y leucocitos, para la regeneración de defectos cutáneos nasales posquirúrgicos. Métodos: Se realizó un estudio cuasiexperimental, longitudinal y prospectivo en el Servicio de Cirugía Maxilofacial del Hospital Universitario "Arnaldo Milián Castro" de la ciudad de Santa Clara, Villa Clara, Cuba, desde septiembre de 2015 hasta junio de 2019. Se efectuó un muestreo intencional, no probabilístico, de 31 pacientes. A partir de una donación de sangre del paciente, se obtuvo una membrana de fibrina rica en plaquetas y leucocitos, la que fue suturada en el defecto nasal posquirúrgico. Se estudiaron variables como el resultado estético, evaluado sobre la base de parámetros como la elasticidad, el color, el volumen y la superficie. Resultados: La edad media fue 62,71 ± 11,09 años y el 61,29 por ciento de la muestra correspondió al sexo masculino. Mostraron un buen resultado estético el 90,32 por ciento de los pacientes, lo que se asoció de forma significativa al grado de epitelización. Conclusiones: Se obtuvo un buen resultado estético en los pacientes donde se utilizó la membrana de fibrina autóloga rica en plaquetas y leucocitos, con independencia de la presencia de diabetes mellitus y hábitos tóxicos. El resultado estético estuvo asociado significativamente al grado de epitelización y a la edad(AU)

Introduction: In the reconstruction of nasal skin defects, several techniques have been used worldwide. Innovative practices use platelet concentrates for their modulating properties and favoring tissue regeneration. Objective: Determine the aesthetic results associated with the use of autologous fibrin rich in platelets and leukocytes, for the regeneration of post-surgical nasal skin defects. Methods: A quasi-experimental, longitudinal and prospective study was conducted in the Maxillofacial Surgery Service of "Arnaldo Milián Castro" University Hospital in the city of Santa Clara, Villa Clara province, Cuba, from September 2015 to June 2019. An intentional, non-probabilistic sampling of 31 patients was carried out. From a blood donation from the patient, a fibrin membrane rich in platelets and leukocytes was obtained, which was sutured in the post-surgical nasal defect. Variables such as the aesthetic result were studied, evaluated on the basis of parameters such as elasticity, color, volume and surface. Results: The mean age was 62.71 ± 11.09 years and 61.29 percent of the sample corresponded to the male sex. A good aesthetic result was shown by 90.32 percent of the patients, which was significantly associated with the degree of epithelialization. Conclusions: A good aesthetic result was obtained in patients where the fibrin membrane rich in leukocytes and autologous platelets was used, regardless of the presence of diabetes mellitus and toxic habits. The aesthetic result was significantly associated with the degree of epithelialization and age(AU)

Morphological assessment of the behavior of three-dimensional anionic collagen matrices in bone regeneration in rats.

The osteogenic behavior of three-dimensional collagenic and anionic matrices (M3DGA) implanted in critical bone defects of 8 mm diameter was morphologically assessed. The defects were performed in the calvaria of 48 adult male (Wistar) rats, and observed at days 15, 30, and 60. The animals were distributed in four groups of equal number: GA1 (M3DGA with 60 min of cross-linking in glutaraldehyde [GA]); GA2 (M3DGA with 30 min of cross-linking in GA); GA3 (M3DGA with 15 min of cross-linking in GA); and G4 (control group, without any implanted biomaterial). The M3DGAs were biocompatible, with mild and regressive chronic granulomatous inflammation, associated with the degradation of their fibers. Furthermore, tissue neovascularization and neomineralization was noted, with statistically significant differences in these amounts among the groups (GA1, GA2, and GA3) and G4. In G4 neoformation was limited to the edges of the defect as well as interstitial fibrosis. Under the experimental conditions and for the parameters analyzed, the M3DGAs had osteogenic behavior, which was more evident in M3DGA 15 min.

A systematic review of animal and clinical studies on the use of scaffolds for urethral repair.

Replacing urethral tissue with functional scaffolds has been one of the challenging problems in the field of urethra reconstruction or repair over the last several decades. Various scaffold materials have been used in animal studies, but clinical studies on use of scaffolds for urethral repair are scarce. The aim of this study was to review recent animal and clinical studies on the use of different scaffolds for urethral repair, and to evaluate these scaffolds based on the evidence from these studies. PubMed and OVID databases were searched to identify relevant studies, in conjunction with further manual search. Studies that met the inclusion criteria were systematically evaluated. Of 555 identified studies, 38 were included for analysis. It was found that in both animal and clinical studies, scaffolds seeded with cells were used for repair of large segmental defects of the urethra, such as in tubular urethroplasty. When the defect area was small, cell-free scaffolds were more likely to be applied. A lot of pre-clinical and limited clinical evidence showed that natural or artificial materials could be used as scaffolds for urethral repair. Urinary tissue engineering is still in the immature stage, and the safety, efficacy, cost-effectiveness of the scaffolds are needed for further study.

Assessment of the Safety of Chondrocyte Sheet Implantation for Cartilage Regeneration.

We have previously studied the effects of chondrocyte sheets on the repair and regeneration of articular cartilage by using temperature-responsive culture inserts. On the basis of this work, we succeeded in rapid fabrication of chondrocyte sheets with the use of a coculture method in which inserts were placed between synoviocytes and chondrocytes. Treatment of cartilage defects using layered chondrocyte sheets promotes repair and regeneration; this method is compatible with in vivo osteoarthritis models that reproduce partial-thickness defects. In human stem cell clinical research guidelines, the Ministry of Health, Labour and Welfare (MHLW) approved several applications related to this technology. Indeed, its translation to a clinical setting is already yielding favorable results. In this study, we evaluated the risk of tumorigenesis associated with this treatment and characterized the dynamics of biological processes associated with the posttransplantation cell sheets in vivo. Furthermore, we also confirmed the safety of the procedure by using array comparative genomic hybridization (array CGH) and G-band staining to screen for deleterious genetic aberrations during prolonged subculture of cells. The safety of chondrocytes that were cultured for longer than normal was confirmed by the array CGH and G-band staining results. In addition, tumorigenicity testing confirmed that culture chondrocyte sheets are not tumorigenic. Furthermore, from the evaluation of bioluminescence imaging following implantation of the cell sheets, it was confirmed that the transplanted chondrocytes and synoviocytes remained in the knee joint and did not transfer elsewhere over time. We believe that the technique used in this study is a highly useful method for evaluating the safety of not only chondrocytes but also extensive subculturing in general.

An in vivo evaluation of a biodegradable genipin-cross-linked gelatin peripheral nerve guide conduit material.

We evaluated peripheral nerve regeneration using a biodegradable nerve conduit, which was made of genipin-cross-linked gelatin. The genipin-cross-linked gelatin conduit (GGC) was dark blue in appearance, which was concentric and round with a rough outer surface whereas its inner lumen was smooth. After subcutaneous implantation on the dorsal side of the rat, the GGC only evoked a mild tissue response, forming a thin tissue capsule surrounding the conduit. Biodegradability of the GGC and its effectiveness as a guidance channel were examined as it was used to repair a 10 mm gap in the rat sciatic nerve. As a result, tube fragmentation was not obvious until 6 weeks post-implantation and successful regeneration through the gap occurred in all the conduits at the three experimental periods of 4, 6, and 8 weeks. Histological observation showed that numerous regenerated nerve fibers, mostly unmyelinated and surrounded by Schwann cells, crossed through and beyond the gap region 6 weeks after operation. Peak amplitude and area under the muscle action potential curve both showed an increase as a function of the recovery period, indicating that the nerve had undergone adequate regeneration. Thus, the GGC can not only be an effective aids for regenerating nerves but can also lead to favorable nerve functional recovery.

Optimized acellular nerve graft is immunologically tolerated and supports regeneration.

To replace the autologous graft as a clinical treatment of peripheral nerve injuries we developed an optimized acellular (OA) nerve graft that retains the extracellular structure of peripheral nerve tissue via an improved chemical decellularization treatment. The process removes cellular membranes from tissue, thus eliminating the antigens responsible for allograft rejection. In the present study, the immunogenicity and regenerative capacity of the OA grafts were tested. Histological examination of the levels of CD(8+) cells and macrophages that infiltrated the OA grafts suggested that the decellularization process averted cell-mediated rejection of the grafts. In a subsequent experiment, regeneration in OA grafts was compared with that in isografts (comparable to the clinical autograft) and two published acellular graft models. After 84 days, the axon density at the midpoints of OA grafts was statistically indistinguishable from that in isografts, 910% higher than in the thermally decellularized model described by Gulati (J. Neurosurg. 68, 117, 1988), and 401% higher than in the chemically decellularized model described by Sondell et al. (Brain Res. 795, 44, 1998). In summary, the results imply that OA grafts are immunologically tolerated and that the removal of cellular material and preservation of the matrix are beneficial for promoting regeneration through an acellular nerve graft.

Plasma treatment for improving cell biocompatibility of a biodegradable polymer scaffold for vascular graft applications.

Biodegradable synthetic scaffolds are being evaluated by many groups for the application of vascular tissue engineering. In addition to the choice of the material and the structure of the scaffold, tailoring the surface properties can have an important effect on promoting adequate tissue regeneration. The objective of this study was to evaluate the effect of an increased hydrophilicity of a polycaprolactone vascular graft by treatment with a cold air plasma. To this end, treated and untreated scaffolds were characterized, evaluated in vitro with smooth muscle cells, and implanted in vivo in the rat model for 3 weeks, both in the subcutaneous location and as an aortic replacement. The plasma treatment significantly increased the hydrophilicity of the scaffold, with complete wetting after a treatment of 60 sec, but did not change fiber morphology or mechanical properties. Smooth muscle cells cultured on plasma treated patches adopt a spread out morphology compared to a small, rounded morphology on untreated patches. Subcutaneous implantation revealed a low foreign body reaction for both types of scaffolds and a more extended and dense cellular infiltrate in the plasma treated scaffolds. In the vascular position, the plasma treatment induced a better cellularization of the graft wall, while it did not affect endothelialization rate or intimal hyperplasia. Plasma treatment is therefore an accessible tool to easily increase the biocompatibility of a scaffold and accelerate tissue regeneration without compromising mechanical strength, which are valuable advantages for vascular tissue engineering.

Biocompatibility and osteoconduction of macroporous silk fibroin implants in cortical defects in sheep.

The goal of the presented study was to compare the biocompatibility and cellular responses to porous silk fibroin (SF) scaffolds produced in a water-based (UPW) or a solvent based process (HFIP) using two different SF sources. For that reason, four different SF scaffolds were implanted (n=6) into drill hole defects in the cancellous bone of the sheep tibia and humerus. The scaffolds were evaluated histologically for biocompatibility, cell-material interaction, and cellular ingrowth. New bone formation was observed macroscopically and histologically at 8 weeks after implantation. For semiquantitative evaluation, the investigated parameters were scored and statistically analyzed (factorial ANOVA). All implants showed good biocompatibility as evident by low infiltration of inflammatory cells and the absent encapsulation of the scaffolds in connective tissue. Multinuclear foreign body giant cells (MFGCs) and macrophages were present in all parts of the scaffold at the material surface and actively degrading the SF material. Cell ingrowth and vascularization were uniform across the scaffold. However, in HFIP scaffolds, local regions of void pores were present throughout the scaffold, probably due to the low pore interconnectivity in this scaffold type in contrast to UPW scaffolds. The amount of newly formed bone was very low in both scaffold types but was more abundant in the periphery than in the center of the scaffolds and for HFIP scaffolds mainly restricted to single pores.