VEGF dose controls the coupling of angiogenesis and osteogenesis in engineered bone.

Vascular endothelial growth factor-A (VEGF) physiologically regulates both angiogenesis and osteogenesis, but its application in bone tissue engineering led to contradictory outcomes. A poorly understood aspect is how VEGF dose impacts the coordination between these two processes. Taking advantage of a unique and highly tunable platform, here we dissected the effects of VEGF dose over a 1,000-fold range in the context of tissue-engineered osteogenic grafts. We found that osteo-angiogenic coupling is exquisitely dependent on VEGF dose and that only a tightly defined dose range could stimulate both vascular invasion and osteogenic commitment of progenitors, with significant improvement in bone formation. Further, VEGF dose regulated Notch1 activation and the induction of a specific pro-osteogenic endothelial phenotype, independently of the promotion of vascular invasion. Therefore, in a therapeutic perspective, fine-tuning of VEGF dose in the signaling microenvironment is key to ensure physiological coupling of accelerated vascular invasion and improved bone formation.

The Medial Femoral Condyle Flap: A Novel Versatile Tool for Complex Microvascular Maxillofacial Reconstruction.

SUMMARY: The medial femoral condyle flap is well-described for reconstruction of small bone defects of the upper and lower extremities. There are limited case reports of its use in other anatomic sites, particularly for reconstruction of complex head and neck defects. In the setting of previous radiation and contaminated fields, vascularized bone is generally preferred to bone grafts, cadaveric allografts, or synthetic implants. The authors present a case series of complex craniofacial defects involving the midface that were reconstructed using medial femoral condyle flaps, focusing on the type of defect and lessons learned from their early experience to promote awareness of this flap among microsurgeons, who may wish to consider the potential of this flap and incorporate its use into their armamentarium. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Robust coupling of angiogenesis and osteogenesis by VEGF-decorated matrices for bone regeneration.

Rapid vascularization of clinical-size bone grafts is an unsolved challenge in regenerative medicine. Vascular endothelial growth factor-A (VEGF) is the master regulator of angiogenesis. Its over-expression by genetically modified human osteoprogenitors has been previously evaluated to drive vascularization in osteogenic grafts, but has been observed to cause paradoxical bone loss through excessive osteoclast recruitment. However, during bone development angiogenesis and osteogenesis are physiologically coupled by VEGF expression. Here we investigated whether the mode of VEGF delivery may be a key to recapitulate its physiological function. VEGF activity requires binding to the extracellular matrix, and heterogeneous levels of expression lead to localized microenvironments of excessive dose. Therefore we hypothesized that a homogeneous distribution of matrix-associated factor in the microenvironment may enable efficient coupling of angiogenesis and bone formation. This was achieved by decorating fibrin matrices with a cross-linkable engineered version of VEGF (TG-VEGF) that is released only by enzymatic cleavage by invading cells. In ectopic grafts, both TG-VEGF and VEGF-expressing progenitors similarly improved vascularization within the first week, but efficient bone formation was possible only in the factor-decorated matrices, whereas heterogenous, cell-based VEGF expression caused significant bone loss. In critical-size orthotopic calvaria defects, TG-VEGF effectively improved early vascular invasion, osteoprogenitor survival and differentiation, as well as bone repair compared to both controls and VEGF-expressing progenitors. In conclusion, homogenous distribution of matrix-associated VEGF protein preserves the physiological coupling of angiogenesis and osteogenesis, providing an attractive and clinically applicable strategy to engineer vascularized bone. STATEMENT OF SIGNIFICANCE: The therapeutic regeneration of vascularized bone is an unsolved challenge in regenerative medicine. Stimulation of blood vessel growth by over-expression of VEGF has been associated with paradoxical bone loss, whereas angiogenesis and osteogenesis are physiologically coupled by VEGF during development. Here we found that controlling the distribution of VEGF dose in an osteogenic graft is key to recapitulate its physiological function. In fact, homogeneous decoration of fibrin matrices with engineered VEGF could improve both vascularization and bone formation in orthotopic critical-size defects, dispensing with the need for combined osteogenic factor delivery. VEGF-decorated fibrin matrices provide a readily translatable platform for engineering a controlled microenvironment for bone regeneration.

The double S technique to achieve aesthetic flat closure after conventional mastectomy.

BACKGROUND: Lateral excess tissue after mastectomy is a frequent problem, which should be included into preoperative planning. Women with lateral tissue abundance are frequently impaired cosmetically and functionally. We suggest a novel oncoplastic mastectomy technique to eliminate the above mentioned. METHODS: Surgical technique Two small horizontal lines are drawn, one line above and one line below the Nipple Areola Complex. These lines should represent the possible skin excision and allow tight skin closure. Consecutively, two ending points of the incision are planned, one close to the xyphoid area and the other one in the anterior axillary line. These points are then interconnected in an s-shaped manner to form a double s-shaped skin excision. RESULTS: The double S-shaped technique is an easy reproducible technique which not only allows good access to the lateral side of the mastectomy, but also and mainly the reduction of lateral fat and skin. CONCLUSION: The double S mastectomy allows for simultaneous removal of access in the axillary region, eliminating skin, and fat as needed and preventing the lateral dog ear.

Evolution of a concept with enzymatic debridement and autologous in situ cell and platelet-rich fibrin therapy (BroKerF).

BACKGROUND: Deep partial-thickness burns are traditionally treated by tangential excision and split thickness skin graft (STSG) coverage. STSGs create donor site morbidity and increase the wound surface in burn patients. Herein, we present a novel concept consisting of enzymatic debridement of deep partial-thickness burns followed by co-delivery of autologous keratinocyte suspension and plated-rich fibrin (PRF) or fibrin glue. MATERIAL AND METHODS: In a retrospective case study, patients with deep partial-thickness burns treated with enzymatic debridement and autologous cell therapy combined with PRF or fibrin glue (BroKerF) between 2017 and 2018 were analysed. BroKerF was applied to up to 15% total body surface area (TBSA); larger injuries were combined with surgical excision and skin grafting. Exclusion criteria were age <18 or >70 years, I°, IIa°-only, III° burns and loss of follow-up. RESULTS: A total of 20 patients with burn injuries of 16.8% ± 10.3% TBSA and mean Abbreviated Burn Severity Score 5.45 ± 1.8 were identified. Of the patients, 65% (n = 13) were treated with PRF, while 35% (n = 7) were treated with fibrin glue. The mean area treated with BroKerF was 7.5% ± 0.05% TBSA, mean time to full epithelialization was 21.06 ± 9.2 days and mean hospitalization time was 24.7 ± 14.4 days. Of the patients, 35% (n = 7) needed additional STSG, 43% (n = 3) of whom had biopsy-proven wound infections. CONCLUSION: BroKerF is an innovative treatment strategy, which, in our opinion, will show its efficacy when higher standardization is achieved. The combination of selective debridement and autologous skin cells in a fibrin matrix combines regenerative measures for burn treatment. LAY SUMMARY: Patients suffering from large burn wounds often require the use of large skin grafts to bring burned areas to heal. Before the application of skin grafts, the burned skin must be removed either by surgery or using enzymatic agents. In this article, we describe a method where small areas of skin are taken and skin cells are extracted and sprayed on wound areas that were treated with an enzymatic agent. The cells are held in place by a substance extracted from patients' blood (PRF) that is sprayed on the wound together with the skin cells. We believe this technique can be helpful to reduce the need of skin grafts in burned patients and improve the healing process.

Case Report: Reconstruction of a Large Maxillary Defect With an Engineered, Vascularized, Prefabricated Bone Graft.

The reconstruction of complex midface defects is a challenging clinical scenario considering the high anatomical, functional, and aesthetic requirements. In this study, we proposed a surgical treatment to achieve improved oral rehabilitation and anatomical and functional reconstruction of a complex defect of the maxilla with a vascularized, engineered composite graft. The patient was a 39-year-old female, postoperative after left hemimaxillectomy for ameloblastic carcinoma in 2010 and tumor-free at the 5-year oncological follow-up. The left hemimaxillary defect was restored in a two-step approach. First, a composite graft was ectopically engineered using autologous stromal vascular fraction (SVF) cells seeded on an allogenic devitalized bone matrix. The resulting construct was further loaded with bone morphogenic protein-2 (BMP-2), wrapped within the latissimus dorsi muscle, and pedicled with an arteriovenous (AV) bundle. Subsequently, the prefabricated graft was orthotopically transferred into the defect site and revascularized through microvascular surgical techniques. The prefabricated graft contained vascularized bone tissue embedded within muscular tissue. Despite unexpected resorption, its orthotopic transfer enabled restoration of the orbital floor, separation of the oral and nasal cavities, and midface symmetry and allowed the patient to return to normal diet as well as to restore normal speech and swallowing function. These results remained stable for the entire follow-up period of 2 years. This clinical case demonstrates the safety and the feasibility of composite graft engineering for the treatment of complex maxillary defects. As compared to the current gold standard of autologous tissue transfer, this patient's benefits included decreased donor site morbidity and improved oral rehabilitation. Bone resorption of the construct at the ectopic prefabrication site still needs to be further addressed to preserve the designed graft size and shape.

Potential benefit in information providing and influence on patient anxiety and satisfaction by means of preoperative explanatory videos in total extraperitoneal inguinal hernioplasty: study protocol of a multicentre, double-blinded, randomised parallel-group controlled trial.

INTRODUCTION: The use of electronic media in informed consent giving has become increasingly important in recent years. Due to the easy access to information via electronical media, patients are primed in a heterogeneous manner concerning expectations and wishes regarding surgical interventions. Inherent to its nature elective interventions are critically questioned as there is time for information gathering and reflection. In this study, we set out to investigate the effect of an educational video as a supporting element in the process of informed consent giving for one the most frequently performed interventions in general surgery, namely inguinal hernia repair. METHODS AND ANALYSIS: In a multicentre setup, eligible patients for primary inguinal hernia repair will be randomly assigned to one of three groups. All three groups will have a preoperative informed consent discussion with a physician in which they will eventually sign the informed consent sheet if participation is desired. Eventually, all three groups will get an online link. For two groups, the link will lead to a video with audiovisual information (an inguinal hernia video for the intervention group and a mock video for the control group). The intervention video provides basic principles of endoscopic extraperitoneal hernia repair. The second video is similar in length and design and displays general aspects of day surgery in the two study centres. All the three study groups will be provided with a copy of the informed consent form as it is standard by now. The third group's link will lead to the digital version of the informed consent brochure. Primary outcomes will consist of (1) score in a multiple choice test assessing gain of knowledge regarding hernia repair, (2) difference in the State-Trait Anxiety Inventory and (3) patient satisfaction questionnaire Individual Clinician Feedback (ICF, Picker Institute, Germany) as assessed 1-2 days after the first consultation. The study design guarantees double blinding, there will be no unblinding at any point. All patients will receive the same, quality and number of medical consultations as well as in the same surgical treatment. (Minor differences in the total extraperitoneal technique of the surgical treatment due to anatomical or pathophysiological differences are independent of the group allocation). Except for the additional videos, there will be no difference in in the information provided and the treatment prior, during or after the hernia repair. ETHICS AND DISSEMINATION: We plan to publish the study in a peer-reviewed journal. The proposed research project has been reviewed by the Cantonal Ethics Committee (BASEC-No 2020-01548). In accordance with national legal regulations in Switzerland stated by the Human Research Act, the proposed project was declared exempt from approval requirement. TRIAL REGISTRATION NUMBER: NCT04494087; Pre-results.

Platelet-rich plasma and stromal vascular fraction cells for the engineering of axially vascularized osteogenic grafts.

Avascular necrosis of bone (AVN) leads to sclerosis and collapse of bone and joints. We have previously shown that axially vascularized osteogenic constructs, engineered by combining human stromal vascular fraction (SVF) cells and a ceramic scaffold, can revitalize necrotic bone of clinically relevant size in a rat model of AVN. For a clinical translation, the fetal bovine serum (FBS) used to generate such grafts should be substituted by a nonxenogeneic culture supplement. Human thrombin-activated platelet-rich plasma (tPRP) was evaluated in this context. SVF cells were cultured inside porous hydroxyapatite scaffolds with a perfusion-based bioreactor system for 5 days. The culture medium was supplemented with either 10% FBS or 10% tPRP. The resulting constructs were inserted into devitalized bovine bone cylinders to mimic the treatment of a necrotic bone. A ligated vascular bundle was inserted into the constructs upon subcutaneous implantation in the groin of nude rats. After 1 and 8 weeks, constructs were harvested, and vascularization, host cell recruitment, and bone formation were analyzed. After 1 week in vivo, constructs were densely vascularized, with no difference between tPRP- and FBS-based ones. After 8 weeks, bone formation and vascularization was found in both tPRP- and FBS-precultured constructs. However, the amount of bone and the vessel density were respectively 2.2- and 1.8-fold higher in the tPRP group. Interestingly, the density of M2, proregenerative macrophages was also significantly higher (6.9-fold) following graft preparation with tPRP than with FBS. Our findings indicate that tPRP is a suitable substitute for FBS to generate vascularized, osteogenic grafts from SVF cells and could thus be implemented in protocols for clinical translation of this strategy towards the treatment of bone loss and AVN.

Orthoplastics in Periprosthetic Joint Infection of the Knee: Treatment Concept for Composite Soft-tissue Defect with Extensor Apparatus Deficiency.

Introduction: Reconstruction of composite soft-tissue defects with extensor apparatus deficiency in patients with periprosthetic joint infection (PJI) of the knee is challenging. We present a single-centre multidisciplinary orthoplastic treatment concept based on a retrospective outcome analysis over 20 years. Methods and Results: One-hundred sixty patients had PJI after total knee arthroplasty. Plastic surgical reconstruction of a concomitant perigenicular soft-tissue defect was indicated in 47 patients. Of these, six presented with extensor apparatus deficiency. One patient underwent primary arthrodesis and five patients underwent reconstruction of the extensor apparatus. The principle to reconstruct missing tissue 'like with like' was thereby favoured: Two patients with a wide soft-tissue defect received a free anterolateral thigh flap with fascia lata; one patient with a smaller soft-tissue defect received a free sensate, extended lateral arm flap with triceps tendon; and two patients who did not qualify for free flap surgery received a pedicled medial sural artery perforator gastrocnemius flap. Despite good functional results 1 year later, long-term follow-up revealed that two patients had to undergo arthrodesis because of recurrent infection and one patient was lost to follow-up. Conclusion: These results show that PJI of the knee and extensor apparatus deficiency is a dreaded combination with a poor long-term outcome. Standardization of surgical techniques for a defined PJI problem and consensus on study variables may facilitate interinstitutional comparisons of outcome data, and hence, improvement of treatment concepts.

Improved Adipocyte Viability in Autologous Fat Grafting With Ascorbic Acid-Supplemented Tumescent Solution.

INTRODUCTION: In reconstructive surgery, fat volume augmentation is often necessary for esthetic or functional reasons. As an alternative to synthetic and xenogeneic materials, autologous fat grafting (AFG) based on liposuction is gaining popularity, yet successful transplantation and long-term volume maintenance are difficult. Standard tumescent solution formulations neglect adipocyte and stromal vascular fraction (SVF) cell survival during extraction, as well as SVF differentiation into adipocytes thereafter, all of which are crucial for the success of AFG. Here we hypothesized that addition of ascorbic acid (AA) to the tumescent solution could prevent liposuction-induced cell damage. MATERIALS AND METHODS: The effect of 0.1 mmol/L AA in tumescent solution was investigated in a previously described ex vivo model of AFG. Briefly, excision fat was infiltrated with tumescent solution, with or without AA, and incubated for 20 minutes at 37°C. Hand-assisted liposuction was then performed with a blunt cannula. Total cell viability, clonogenicity, and differentiation capacity of the SVF cells were assessed. RESULTS: With AA, 10.3% more cells and in particular 14.9% more adipocytes survived liposuction. Clonogenicity, adipocyte and osteoblast differentiation by SVF cells remained unchanged. CONCLUSIONS: Addition of AA successfully improved survival of adipocytes during liposuction without affecting SVF growth and differentiation. This study therefore identified a useful supplement to the tumescent solution which may lead to improving AFG success.

Reconstruction of Spinal Soft Tissue Defects With Perforator Flaps From the Paraspinal Region.

BACKGROUND/AIM: Reconstruction of spinal soft tissue defects is challenging, especially when neural structures or prosthetic material are exposed. They should be covered with well-vascularized tissue such as paraspinal perforator flaps. MATERIALS AND METHODS: This is a retrospective study of soft tissue reconstructions with paraspinal perforator flaps from 2011 to 2018. The technique is described and risk factors for poor wound healing were assessed. Postoperative complications are reported. RESULTS: Twenty patients with a mean age of 63.65 years were included. Defects had an average size of 47 cm2 and were mainly located in the lumbosacral region (9 patients). Twelve patients suffered from infection following spinal stabilization, seven of whom were diagnosed with osteomyelitis, two patients presented with pressure sore and one patient experienced wound dehiscence. One partial flap necrosis with a lumbar defect occurred, which required revision surgery. No total flap loss occurred. Stable, closed wounds were achieved at their final follow-up. CONCLUSION: Perforator paraspinal flaps are suitable for immediate reconstruction of spinal defects.

Prefabrication of a large pedicled bone graft by engineering the germ for de novo vascularization and osteoinduction.

Large and complex bone defects represent challenging clinical scenarios, typically requiring autologous vascularized bone transplants. In order to bypass the numerous associated limitations, here we aimed at ectopically prefabricating a bone graft surrogate with vascular pedicle. A hollow cylinder of devitalized cancellous bone was used to define the space of a large bone substitute. This space was filled with devitalized pellets of engineered hypertrophic cartilage as bone-inducing material, in combination or not with stromal vascular fraction (SVF) of adipose tissue as source of osteoprogenitors and endothelial cells. Vascularization of the space was targeted through axial insertion of an arterio-venous (AV) bundle. Constructs were subcutaneously implanted in nude rats for 12 weeks and analyzed for bone formation and vascularization by histology and microtomography. Retrieved constructs were extensively vascularized in all conditions, with vessels sprouting from the AV bundle and reaching a higher density in the axially central volume. Bone tissue was formed through remodeling of hypertrophic cartilage, and quantitatively correlated with de novo vascularization. Our study demonstrates feasibility to prefabricate large, pedicled bone grafts in predefined shapes. The combination of an AV bundle with engineered hypertrophic cartilage provided a germ for the coupled processes of vascularization and bone formation. The demonstrated osteoinductivity of devitalized hypertrophic cartilage offers the opportunity of implementing the proposed regenerative surgery strategy through off-the-shelf materials.

It Takes Two to Tango: Coupling of Angiogenesis and Osteogenesis for Bone Regeneration.

Bone regeneration is a complex process requiring highly orchestrated interactions between different cells and signals to form new mineralized tissue. Blood vessels serve as a structural template, around which bone development takes place, and also bring together the key elements for bone homeostasis into the osteogenic microenvironment, including minerals, growth factors and osteogenic progenitor cells. Vascular endothelial growth factor (VEGF) is the master regulator of vascular growth and it is required for effective coupling of angiogenesis and osteogenesis during both skeletal development and postnatal bone repair. Here, we will review the current state of knowledge on the molecular cross-talk between angiogenesis and osteogenesis. In particular, we will focus on the role of VEGF in coupling these two processes and how VEGF dose can control the outcome, addressing in particular: (1) the direct influence of VEGF on osteogenic differentiation of mesenchymal progenitors; (2) the angiocrine functions of endothelium to regulate osteoprogenitors; (3) the role of immune cells, e.g., myeloid cells and osteoclast precursors, recruited by VEGF to the osteogenic microenvironment. Finally, we will discuss emerging strategies, based on the current biological understanding, to ensure rapid vascularization and efficient bone formation in regenerative medicine.

Capturing Plastic Surgery on Film-Making Reconstruction Visible.

The Swiss Plastic Surgery Association (https://plasticsurgery.ch/en/) decided to produce a corporate video to illustrate the concept of "plastic surgery of confidence" to the public. We show the diversity of specializations and the vast range of tasks that surgeons passionately handle day in and day out. We wanted to convey 2 main messages: first, that plastic surgery is more than just cosmetic surgery, and second, that plastic surgery in Switzerland is synonymous with quality and confidence. We selected 17 topics that we felt had good filmic potential and would best explain to the public what plastic surgery is about. This included the selection of appropriate patients, experts, and locations from all over the country. We thought it crucial to show the initial preoperative situation, as only in this case would the achievement of reconstruction be evident and comprehensive to the layman audience. The actual production was filmed in 5 different locations and took 5 days of shooting. We recorded 17 surgeons, 9 patients, and about 30 voluntary background actors. From 23 hours of footage, we created a 7 minute, 22 second corporate video, recorded in 3 of the Swiss national languages. The video was presented to the public online in June 2016, on the same day as the National Open Day of Plastic Surgery in Switzerland. The video is available online. We evaluated the impact of the video using a questionnaire for lay people and observed that it could substantially improve the perception of our specialty, especially regarding the reconstructive aspect. We feel that a freely available corporate video is a very useful means to promote plastic surgery and help patients better understand what it is all about.

[Early active motion management of volar plate disruption of the proximal interphalangeal joint after finger hyperextension injury: extension block splinting versus buddy taping]. / Frühfunktionelles Management bei Hyperextensionstraumata des proximalen Interphalangealgelenkes mit Läsion der palmaren Platte: Extensionsblock versus Achterschlaufe.

Background Volar plate disruption of the proximal interphalangeal joint (PIP) is a common hand injury following finger hyperextension. At our institution, patients presenting with disruptions of the palmar plate (Eaton and Littler types I and II) before 2011 were treated with extension block splinting (group A). Since 2011, all patients with Eaton and Littler types I and II have received buddy taping (group B). The aim of this retrospective study was to compare the respective treatment outcomes. Patients and Methods In this retrospective study, we analysed the data of 44 patients visiting our department with volar plate disruption (Eaton and Littler types I and II) from 2009 to 2012. In group A, 23 patients were treated with custom-made extension block splinting in 10 ° flexion, compared with 21 patients treated with buddy taping in group B. Both groups received dorsal night splinting in 10 ° flexion. Results No statistically significant differences between the two groups were found in regard to treatment duration (p = 0,981), amount of required treatment sessions (p = 0,271), total active motion (TAM) (p = 0,693) and extension deficit (p = 0,404) in the PIP joint at the end of treatment, time until hand therapy was started (p = 0,285) or the Eaton und Littler diagnosis (p = 0,241). In the extension block group (group A), 10 out of 23 (44 %) patients after a median of 9 (4-10) weeks of treatment had an excellent result, 11 (48 %) had a good result, and 2 (8 %) patients had a poor result with a median 90 ° (85-100 °) TAM in the PIP joint and no extension deficit. In group A, all patients received a median of 4 (3-6) treatment sessions. Of those treated with buddy taping (group B), 14 out of 21 (66 %) patients at a median of 6 (4-13) weeks had an excellent result, 6 (29 %) had a good result, and 1 (5 %) patient had a poor result with a median TAM of 95 ° (82,5-100 °) and no extension deficit. In this group, patients received a total of 4 (3-5) treatment sessions. The type of treatment had no significant influence on the Benke and Stableforth outcome (χ2 = 2,385, df = 3, p = 0,304). No patient developed palmar joint instability. Conclusion No treatment option proved to be superior. We consider buddy taping to be faster, easier and more flexible to use.