Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview.

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models.

Secondary "Hybrid Reconstruction" Concept with Silicone Implants After Autologous Breast Reconstruction - Is It Safe and Reasonable?

BACKGROUND The use of autologous tissue for breast reconstructive surgery following mastectomy has become routine and allows for excellent symmetry and aesthetic results. However, in some cases, the amount of tissue available from the utilized flaps is not enough to achieve the desired outcome. The use of autologous fat grafting, as well as other techniques, has been described to deal with such problems. However, though well-established, these techniques may also fail to achieve the desired results. The aim of this study was to highlight the opportunity to improve aesthetic results using a secondary prosthesis underneath the previously used free flap and to examine whether this is a safe and reasonable procedure. MATERIAL AND METHODS In our study we included patients with unsatisfied aesthetic results after free flap procedures (DIEP, S-GAP, TMG, and FCI) between 2011 and 2018. In each case described, a secondary prosthesis was placed underneath the original flap in order to improve symmetry, shape and projection. Patient age, indication for surgery, adjuvant therapy, complications and outcomes have been registered. A 12-point scale was established to analyze patient satisfaction and aesthetic outcome. RESULTS Overall "operative success" was achieved in all 13 patients (14 flaps) evaluated. At 12 months after reconstruction, all aesthetic scores collected were between good and excellent. In contrast to other studies, we chose a secondary approach for the flap augmentation and we used the epipectoral pocket for the placement of the implant. In our series, low rates of early and late post-operative complications were observed, with a high overall rate of satisfaction. CONCLUSIONS The demonstrated "Hybrid Breast Reconstruction" approach, using an implant underneath a free flap autologous breast reconstruction, provided a safe and reliable option to optimize breast reconstruction outcomes.

Is there a Rationale for Autologous Breast Reconstruction in Older Patients? A Retrospective Single Center Analysis of Quality of life, Complications and Comorbidities after DIEP or ms-TRAM Flap Using the BREAST-Q.

Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap is a common method in the majority of patients after mastectomy. Because of an increased perioperative risk profile the benefit in older patients is questionable. To assess the postoperative quality of life and peri- and post-operative complications of older compared to younger patients is the aim of this retrospective study. In a retrospective analysis 39 older (i.e. >60 years) and 140 younger patients (i.e. <60 years) with autologous breast reconstruction in the Department of Plastic Surgery at the University Hospital of Erlangen-Nuernberg were surveyed at least 6 month postoperative using the BREAST-Q questionnaire. Correlations were generated between comorbidities and complications. Significant differences were observed regarding hospitalization, pre-existing diseases and the choice of DIEP versus ms-TRAM flaps. Parameters such as major and minor complications, bulging or hernia and risk factors (e.g. smoking or obesity) showed no significant differences. The results of the questionnaire parameters showed no significant difference between both groups, revealing high satisfaction with the aesthetic result and an improvement in quality of life independent of age. Autologous breast reconstruction after mastectomy generates a gain in quality of life and shows a good to excellent overall satisfaction in older as well as younger patients. Despite a longer hospitalization and a different risk profile there were no significant differences regarding minor and major complications in the postoperative course. Hence autologous breast reconstruction for older patients is justified and should be taken into consideration.

Double pedicled perforator flap to close flank defects: an alternative for closure of a large lumbar defect after basalioma excision--a case report and review of the literature.

Large defects following resection of skin cancers are sometimes a challenge for the reconstructive surgeon. Although skin grafts are considered as the first choice for reconstruction of large skin defects at the trunk region, pedicled or free flaps provide sometimes a superior functional and aesthetic outcome. Perforator flaps represent a valuable option for these patients. The progress in understanding the perforator vessel system of the body facilitated the development of a plethora of novel pedicled flaps which could be transferred over long distances with minimal donor site morbidity. We present a patient suffering from a large exulcerated basalioma at the lumbar region. The skin defect after excision was reconstructed using a novel concept based on 2 independent pedicled perforator flaps, a lumbar artery perforator, and a lateral intercostal artery perforator.

Aesthetic correction of tuberous breast deformity: lessons learned with a single-stage procedure.

Tuberous breast deformity is a pathologic condition of the breast affecting teenage women. The aberration of breast shape in tuberous breast deformity consisting of a constricting ring at the breast base, breast tissue deficiency, and herniation of breast tissue into the nipple-areola-complex with areola enlargement and additional asymmetry makes the surgical correction challenging. In the present study, 15 patients were operated using a surgical procedure, which addresses all aspects of the deformity at a one-stage operation. The described technique results in a periareolar scar only, and the use of tissue expanders or skin flaps is unnecessary. Minor periareolar scar revision surgery was necessary in eight of 15 patients (53%) because of hypertrophic or expanded scarring. In two patients, implant dislocation occurred and therefore surgical revision was necessary. In all cases, an excellent final aesthetic result with a high patient satisfaction was achieved.

Intrapulmonary and cutaneous siliconomas after silent silicone breast implant failure.

Since the implementation and use of silicone implants in breast surgery the risks are published and discussed. Especially, the incidence of late silicone implant rupture and its potential risk to induce local siliconomas are still under discussion and not sufficiently evaluated. So far literature data offer no information of intrapulmonal or peripheral located cutaneous siliconomas because of systemic migration of silicone after breast augmentation. In light of silicones checkered history, and given the large and growing number of women who choose to undergo breast augmentation surgery each year, the presented clinical findings in our study are likely to be of interest to medical professionals, producers, and consumers alike. We present six female patients with an average age of 55 (+/-5) years with bilateral rupture of silicone implants after breast augmentation for aesthetic reasons. The average time after operation was 18 (+/-6) years. In five patients, we identified peripheral located cutaneous siliconomas and one patient suffered from an intrapulmonal siliconoma. The diagnosis of bilateral rupture of the silicone implants was performed preoperatively by MRI-scans. All five peripheral cutaneous siliconomas and the intrapulmonal siliconoma were validated by histopathologic analysis. Six female patients suffered from bilateral rupture of silicone implants after breast augmentation. In five patients, we identified peripheral located cutaneous siliconomas which were surgically excised. One patient suffered from an intrapulmonal siliconoma. In this unique case a lobectomy with resection of the pulmonal segment 10 had to be performed. Clinical findings of peripheral cutaneous and even intrapulmonary siliconomas after bilateral rupture of silicone breast implants indicate a systemic hematogen or lymphatic pathway of silicone. These findings suggest that it is mandatory to inform the patient about the potential risk of local siliconomas, but also about the potential risk of peripheral cutaneous or even intrapulmonary siliconomas caused by systemic hematogen or lymphatic pathways of silicone after silent implant failure.

Aesthetic and functional correction of female, asymmetric funnel chest - a combined approach.

There is still sparse information published about the surgical correction of female funnel chest deformity. Women with severe asymmetric funnel chest deformity often present with asymmetric, hypoplastic breasts. These patients frequently complain of physiological limitations in connection with gross aesthetic impairment. To correct these two features a combined approach is presented in this study. 10 women were operated with correction of the thoracic wall deformity by open retrosternal mobilisation and metal plate fixation. Either during the same procedure or in a secondary operation, submuscular breast augmentation was performed to correct breast hypoplasia and asymmetry. All patients tolerated the operation very well without any complications. Aesthetic outcome was rated good to excellent in secondary breast augmentation, whereas simultaneous implant positioning was prone to cause symmastia. In conclusion we recommend correction of female asymmetric funnel chest by primary sternal reduction with secondary breast augmentation during metal plate removal 1 year after.

Acute and diffuse postoperative bleeding after free latissimus dorsi flap--Factor XIII deficiency: a case report and review of the literature.

BACKGROUND: Factor XIII deficiency is a rare inherited bleeding disorder that is often difficult to diagnose. As there are no standard screening tests established patients with Factor XIII deficiency are not correctly identified. Especially postoperative bleeding and haemorrhage after difficult plastic reconstructive operations such as free flap transfer may lead the plastic surgeon to the wrong diagnosis. This again leads to the wrong indication such as revision with the aim to find a surgical origin of bleeding. Instead a haematological deficiency such as Factor XIII is the reason for acute postoperative bleeding and haemorrhage. CASE REPORT: We report the case of a 69-year old Caucasian male who received a free latissimus dorsi flap to the right knee after osteomyelitis and infection of a knee total endoprothesis. The patient had severe postoperative bleeding and haemorrhage from all 8 drains including the donor side of the split thickness skin graft area. Shortly before the indication of performing a revision and trying to find the surgical origin of bleeding a factor XIII test was performed. The results showed a high deficiency of factor XIII which was immediately replaced by 2500 Units (i.E.) Fibrogammin. Within 12 hours the bleeding rapidly reduced and no revision was necessary. CONCLUSIONS: Postoperative acute but diffuse bleeding after free flap operations in plastic surgery may not be all due to insufficient operative techniques.

Foreign body reaction after usage of tissue adhesives for skin closure: a case report and review of the literature.

INTRODUCTION: The usage of tissue adhesives such as 2-octyl cyanoacrylate is a standard tool for closure of superficial wounds of the body. The benefits using 2-octyl cyanoacrylate are well known and appreciated by surgeons world wide. Especially in superficial or small wounds in children where no surgical procedure is wanted this technique is commonly used. However, so far the risks and possible complications after using 2-octyl cyanoacrylate are not sufficiently published and discussed. CASE REPORT: We report a case of foreign body reaction after 3 weeks in a 39-year-old female patient after usage of 2-octyl cyanoacrylate treating a superficial wound of the right wrist. CONCLUSION: The use of 2-octyl cyanoacrylate for the closure of superficial and small wounds or lacerations is a simple, quick and comfortable method. However, there is clinical evidence that in some cases the use of this type of tissue adhesive may lead to foreign body reaction. We suggest that each patient who is treated by this type of wound closure technique should be mandatory informed on the potential risk of a foreign body reaction.

Pseudotumors after primary abdominal lipectomy as a new sequela in patients with abdominal apron.

BACKGROUND: Malnutrition and overweight is a common problem in modern societies. Primary abdominal lipectomy is a standard surgical tool in patients with these problems. However, unknown secondary problems result from recent advances in obesity surgery. Plication of the anterior musculoaponeurotic wall is a widely and commonly used operative technique during abdominoplasty. Many different plication techniques have been published. So far no common standard and long-term effectiveness is proven. In addition, there is no sufficient literature dealing with the postoperative risks of plication of the musculoaponeurotic wall. METHODS: Four patients with development of pseudotumors were reviewed. All four patients received 12 months in advance a primary abdominal lipectomy including a vertical plication of the musculoaponeurotic wall. RESULTS: All four patients were females with mean age of 61 years and mean body mass index (BMI) of 37 kg/m(2). All four patients had developed a pseudotumor of the abdomen as a long-term complication more than 12 months after primary abdominal lipectomy including a vertical plication of the anterior rectus sheath. CONCLUSION: One should be aware of the potential long-term risk of secondary postoperative hematoma formation, with or without partial necrosis of the anterior rectus sheath after vertical plication of the anterior musculoaponeurotic wall. Viewed clinically and radiologically, such sequelas may appear as pseudotumor like masses and require immediate revision.

Coverage of exposed bones and joints in critically ill patients: lower extremity salvage with topical negative pressure therapy.

BACKGROUND: Soft tissue defects of the limb with exposure of tendons and bones in critically ill patients usually lead to extremity amputation. A potential treatment with topical negative pressure may allow split-thickness skin grafting to the bone, which leads to limb salvage. MATERIALS AND METHODS: We report on 21 multimorbid patients, 46 to 80 years of age, with severe lower limb soft tissue loss and infection with exposed bone following débridement with critical limb ischemia. Attempts to salvage the extremities were undertaken with repeated surgical débridement followed by vacuum-assisted closure therapy and subsequent split-thickness skin grafting procedures. RESULTS: Infection control and limb salvage were achieved in all cases with multiple débridements, topical negative pressure therapy, and skin grafts. In all patients, the exposure of tendons and bones was reversible by this strategy without a free flap transfer. DISCUSSION: The patients described in this study were severely compromised by systemic and vascular disorders, so extremity amputation had been considered owing to the overall condition and the exposure of tendons and bones. Since it was possible to salvage the affected limbs with this straightforward and simple procedure, this type of treatment should be considered as a last attempt to prevent amputation.

Improved safety of autologous breast reconstruction surgery by stabilisation of microsurgical vessel anastomoses using fibrin sealant in 349 free DIEP or fascia-muscle-sparing (fms)-TRAM flaps: a two-centre study.

BACKGROUND: We routinely perform free DIEP flap and fascia-muscle-sparing (fms) TRAM flap procedures using fibrin sealant to stabilise anastomosed vessels, thus avoiding some of the difficulties associated with microsurgical anastomoses. METHODS: Women undergoing elective, autologous breast reconstruction with free DIEP flaps or fms-TRAM flaps between June 2004 and June 2007 in two Interdisciplinary Breast Centres were included in a retrospective chart review. RESULTS: A total of 349 breast reconstructions were performed in 325 women. Of these, 201 (57.6%) were free DIEP flap procedures and 148 (42.4%) were fms-TRAM flap procedures. Average hospital stay was 9.8 days. Complete flap loss was seen in 3 cases (0.9%). Low rates of post-operative complications were observed. CONCLUSIONS: Microsurgical breast reconstruction using free DIEP flaps and fms-TRAM flaps, with fibrin sealant for stabilisation of microvascular anastomoses, provides good post-operative outcome featuring a low incidence of flap loss or other common post-operative complications.

Intrinsic axial vascularization of an osteoconductive bone matrix by means of an arteriovenous vascular bundle.

BACKGROUND: The purpose of this study was to generate an autonomously vascularized hard-tissue construct suitable for microsurgical transfer. The effector of vascularization was an arteriovenous bundle inserted into a specially designed channel in the matrix. The authors also evaluated corrosion cast and intravital magnetic resonance angiography as methods for monitoring and quantifying the angiogenic response. METHODS: Thirty inbred male Lewis rats were divided into two groups. In both groups (n = 15), a disk of processed bovine cancellous bone matrix was placed into an isolation chamber. In group A, a ligated arteriovenous bundle was inserted into the biogenic matrix as a vascular carrier. In group B, there was no vascular carrier. At 2, 4, and 8 weeks after implantation, four constructs per group were evaluated by means of histology and histomorphometry and one by scanning electron microscopy of vascular corrosion casts. Micro-magnetic resonance angiography was used for intravital evaluation of the vascularized matrices. RESULTS: Vascular density was higher in group A. The capillary network in group A displayed a higher degree of maturation, with organization into vessels of different orders. Both the sprouting and intussusceptive modes of angiogenesis could be documented. Micro-magnetic resonance angiography showed a patency rate of approximately 75 percent in the bundle. CONCLUSIONS: The authors zeroed in on the issue of vascularization. The results might provide a basis for further investigations on induction of bone formation in axially prevascularized matrices. Axially vascularized bone substitutes might solve issues of availability in mass and form and provide perfusion autonomy in sites of impaired circulation.

The versatility of the distally based peroneus brevis muscle flap in reconstructive surgery of the foot and lower leg.

Soft tissue and bone defects of the lower leg, ankle, and heel region often require coverage by local or distant flaps. The authors successfully used the distally based peroneus brevis muscle flap for the treatment of 15 patients with osteomyelitis (n = 5), melanoma (n = 1), Achilles tendon defects (n = 6), posttraumatic bone defects (n = 2), and chronic diabetic heel ulcer (n = 1). The size of the defects ranged from 6 to 60 cm. All defects were covered successfully without major complications by the muscle flap. The distally based peroneus brevis muscle represents a very reliable flap for coverage of small and moderate defects of the medial and lateral malleolus, the Achilles tendon, and the heel area. This flap offers a convincing alternative for covering defects in the distal leg region and is often preferable to the use of free flaps because the surgery is rapidly performed and does not require microsurgical expertise.

Tissue engineering of injectable muscle: three-dimensional myoblast-fibrin injection in the syngeneic rat animal model.

BACKGROUND: Surgical treatment of skeletal muscle loss resulting from trauma, tumor ablation, or inborn tissue defects is hampered by the scarcity of functional substitute tissue. By using techniques of tissue engineering, reconstitution of skeletal muscle defects might become a more viable option. However, it is necessary to develop an adequate, practical method for delivering myoblasts within a three-dimensional scaffold in vivo. The aim of this study was to create and evaluate a novel method for the transfer of myoblasts with clinically approved components within a three-dimensional matrix. METHODS: The authors injected expanded primary male myoblasts into muscle defects in female syngeneic rats using a two-way syringe (Duploject) within a three-dimensional fibrin matrix. Detection and evaluation were performed using Y chromosome in situ hybridization, antidesmin immunostaining, and hematoxylin and eosin staining. To identify possible differences by means of integration, the injected myoblasts were compared with 7 days of precultivated constructs. RESULTS: Injected myoblasts showed increasing integration into host muscle fibers in a time-dependent manner, exclusively at the injection site. Antidesmin staining revealed a conserved myogenic phenotype of transplanted cells. The fibrin matrix resolved over a period of 12 weeks, with no indication of an inflammatory reaction. No significant difference in the number of detected Y chromosome-positive nuclei was found between the two transplantation groups. CONCLUSIONS: The presented technique of myoblast-fibrin injection indicates a clinical potential for reconstruction of skeletal muscle defects in vivo using a ready-to-use device in combination with tissue-engineering methods.