Graft orientation influences meshing ratio

OBJECTIVES

The technique of meshed skin grafting is known since 1960s. It was shown that there is a difference between the declared and real expansion ratio of the skin meshed graft. We hypothesize that the orientation of the Langer's lines in a split thickness skin graft is a key parameter in the resulting expansion ratio.

METHODS

The skin graft meshing process was analyzed in two steps. In the first step, ex vivo uniaxial tests of human skin were performed. This served as an input for the constitutive model used for numerical simulations. In the second step, finite element analyses were performed so that stress distributions and expansion ratios could be determined.

RESULTS

It was shown that peaks of true stress tended to be concentrated around the vertex of the mesh pattern region for all cases. The declared expansion was impossible to obtain for all expansion ratios having the meshing incision perpendicular to the Langer's lines. The highest difference between declared and real expansion ratio reaches 37%.

CONCLUSIONS

With regard to literature dealing with expansion of skin grafts by meshing, a high scatter amongst data results is observed. This finding was also explained by our research, demonstrating the significance of Langer's lines and their relative orientation to the direction of meshing.

Stem cells: their source, potency and use in regenerative therapies with focus on adipose-derived stem cells - a review

Stem cells can be defined as units of biological organization that are responsible for the development and the regeneration of organ and tissue systems. They are able to renew their populations and to differentiate into multiple cell lineages. Therefore, these cells have great potential in advanced tissue engineering and cell therapies. When seeded on synthetic or nature-derived scaffolds in vitro, stem cells can be differentiated towards the desired phenotype by an appropriate composition, by an appropriate architecture, and by appropriate physicochemical and mechanical properties of the scaffolds, particularly if the scaffold properties are combined with a suitable composition of cell culture media, and with suitable mechanical, electrical or magnetic stimulation. For cell therapy, stem cells can be injected directly into damaged tissues and organs in vivo. Since the regenerative effect of stem cells is based mainly on the autocrine production of growth factors, immunomodulators and other bioactive molecules stored in extracellular vesicles, these structures can be isolated and used instead of cells for a novel therapeutic approach called "stem cell-based cell-free therapy". There are four main sources of stem cells, i.e. embryonic tissues, fetal tissues, adult tissues and differentiated somatic cells after they have been genetically reprogrammed, which are referred to as induced pluripotent stem cells (iPSCs). Although adult stem cells have lower potency than the other three stem cell types, i.e. they are capable of differentiating into only a limited quantity of specific cell types, these cells are able to overcome the ethical and legal issues accompanying the application of embryonic and fetal stem cells and the mutational effects associated with iPSCs. Moreover, adult stem cells can be used in autogenous form. These cells are present in practically all tissues in the organism. However, adipose tissue seems to be the most advantageous tissue from which to isolate them, because of its abundancy, its subcutaneous location, and the need for less invasive techniques. Adipose tissue-derived stem cells (ASCs) are therefore considered highly promising in present-day regenerative medicine.

[Treatment Options for Inveterate Injuries of Deep Finger Flexors - Primary Transplantation with Tendon Graft]

Injuries of the flexor finger apparatus are very common. Primarily, it is routinely treated by suture of the tendon. Isolated deep flexor injuries, when the flexion restriction only reaches the DIP joint, are sometimes overlooked by the surgeon or by the patients themselves, especially if the deep flexor is injured, after a closed rupture or cutaneous injury with a small skin wound. The patient is then sent to a department specializing in hand surgery after a few weeks. Subsequent shortening of the tendon apparatus makes flexor suture more difficult or sometimes even impossible. Many ways of suturing the tendons and subsequent treatment are described. The treatment results vary immensely. It depends on the mechanism of injury, injury zone, the suture suture technique used, time that has elapsed since primary treatment, surgeon experience and subsequent postoperative and rehabilitative care. One of them is reconstruction of the flexor apparatus by primary transplantation of an autologous tendon graft. Most commonly, the tendon graft is taken from the palmaris longusfrom the same hand. The tendon graft can subsitute the entire area of zones I and II. The tendon suture is made in the palm proximal to the A1 pulley outside the tendon sheath in the area where the muscular belly of thelumbricalis is located on the tendon of the deep flexor. The distal end is reinserted to the base of the distal phalanx. The primary use of the autologous tendon graft can be used in the reconstruction of obsolete deep-flexor injuries in Zone II, but also in primary treatments. This type of treatment has a number of advantages. Performing the reinforcement of the tendon at the base of the distal phalanxand the suture in the palm of the hand completely eliminates the complications caused by the tendon suture in zone II. There is no injury to the tendon sheath, or the need for intersection of the tendons. The transplanted tendon is smaller in diameter than the deep flexor, so it can also be used for older injuries when the tendon sheath is in partially missing. It removes painful palmar resistance by restoring the right position and a tension of tendon of lumbricalis and the tendon of the deep flexor. This type of reconstruction allows immediate active or semi-rehabilitation of the hand and fingers. Key words:tendon, injury, hand, transplantation, surgery, flexor, reconstruction, rupture, treatment.

PULMONARY EMBOLISM AFTER ABDOMINOPLASTY - ARE WE REALLY ABLE TO AVOID ALL COMPLICATIONS? CASE REPORTS AND LITERATURE REVIEW

Pulmonary embolism is a potentially lethal complication in plastic surgery patients. About 34% of the members of American Society of Plastic Surgery have diagnosed pulmonary embolism in their patients, and 7% had experienced at least 1 death due to this complication. The American Society of Plastic Surgeons Executive Committee approved the Venous Thromboembolism Task Force Report. The members agreed that there was not enough evidence to make all-inclusive recommendations for plastic surgery deep vein thrombosis and pulmonary embolism prophylaxis, but released the 2005 Caprini Scale accompanied by the Task Force recommendations for use in plastic surgery. It is generally strongly advised to use appropriate prophylactic measures against venous thromboembolism in all surgical procedures. However, even then we cannot completely avoid this serious complication.

TRACHEAL ALLOTRANSPLANTATION AND REGENERATION

Non-malignant and malignant obstruction of the tracheal airway causes significant morbidity and mortality. With increased use of artificial airways, benign and iatrogenic complications are increasing. A tracheal stenosis that is less than 5 cm in length can be resected with end-to-end anastomosis. Longer tracheal lesions can be treated in a palliative way by placement of a stent to secure airway lumen patency. The management of tracheal defects is an evolving field. Tracheal transplantation and tracheal regeneration may provide major treatment advances to cases with long-segment tracheal involvement. This review examines the current possibilities and future prospects in the area of tracheal transplantation and regeneration.

NUMERICAL EVALUATION OF SCAR AFTER BREAST RECONSTRUCTION WITH ABDOMINAL ADVANCEMENT FLAP

BACKGROUND

The treatment of breast cancer has developed a lot during the last decade, nevertheless it still remains a considerable social and economical problem all over the world. The choice of the surgical procedure depends on a patients protocol and the surgeons preferences. The aim of this study is to evaluate the stress on the scar after breast reconstruction.

METHODS

Mathematical modeling of the sutured skin flap used for breast implant placement was divided into the following two steps. At first, material model of the selected silicone implant was identified. Afterwards, the mathematical model of the breast and implant was performed.

RESULTS

Maximal geometrical deviation for anatomical and round implant is placed on the lower surface of the breast and upper surface of the breast, while in the area of lateral geometry and the area around the nipple the agreement reaches very high level. The maximal tension is located in two median stitches. The maximal force reaches 0.025 N. The Cauchy stress equivalent is located around the nipple and reaches the value of 380 kPa.

CONCLUSION

From our results it can be seen, that the anatomical and round breast implants do not result in the same stress on the scar. The maximal value difference reaches 13.4% between stress values for these two breast implants and the round implant results in higher loaded scar compared to the anatomical implant.

TRANSPLANTATION OF VASCULARIZED COMPOSITE ALLOGRAFTS. REVIEW OF CURRENT KNOWLEDGE

Transplantation in reconstructive surgery has been performed for more than 20 years, although the official beginning of these procedures is considered the first successful transplantation of the hand in 1998. The original name "Composite Tissue Transplantation" has been used less frequently; more common is the term "Vascularized Composite Allotransplant", which better describes the basis of the procedure. There have been so far approximately 180 transplantations performed, the exact number is difficult to find. The most known transplantation from this group include transplantation of the hand and face, the other, such as transplantation of the abdominal wall, joints, bones, trachea, larynx, tongue, penis, uterus, etc. are less common and less well known. The common characteristics is that they are not used for salvage or prolongation of life, but to improve its quality. The quality of life is a value, which cannot be objectively measured and the opinions regarding its importance significantly differ. Therefore there is still an unsolved ethical issue regarding these procedures, which is based on the justification to use immunosuppressive therapy with its serious risks in cases when the procedure is not needed for salvage or preservation of life.

Reconstructive procedures in maxillofacial oncosurgery

OBJECTIVE

Oropharyngeal cancers are a biologically heterogenous group of tumors with diverse risk factors including tobacco, alcohol, HPV, inherited disorders, the acquired immunodeficiency of Karposi's Sarcoma and non Hodgkin's lymphoma. In the Czech Republic, oropharyngeal cancers represent around 2% of all cancers. The treatment of these tumors is long and complex. Reconstructive procedures in maxillofacial oncosurgery demand good interdisciplinary collaboration and great professional preparedness of the surgical and nursing team. Patient age and stage of disease, including the presence of metastases are of key importance. A prerequisite for the success of surgical treatment is removal of the tumor with a sufficient safety margin. Reconstructive procedures then follow.

AIM

To highlight the importance of radical tumor resection and describe reconstruction of the defect in a group of our patients.

METHODS AND RESULTS

From 2008 to 2013, 23 patients with oropharyngeal carcinoma underwent radical surgical removal of tumor, followed by reconstruction of postoperative defects using distant and free flaps. The histopathology showed predominantly squamous cell carcinomas and one of Merkel cell carcinoma. 16 patients had malignant disease detected in III-IV. In only 7 cases was treatment initiated in the first and second stages of the disease. In these patients, the tumors were removed with a safety margin of healthy tissue and in none, did the basic cancer recur . The postoperative course in terms of flap engraftment and overall condition of the patient was uneventful. All of these patients still enjoy a good life quality with a current mean survival in range 5 - 76 months. Radical surgical removal of a malignant tumor in the early stages of the disease is associated with fewer postoperative complications and longer survival.

CONCLUSION

To avoid the risk of local and/or systemic postoperative complications, appropriate patient selection is important. Overall, the traditional, classic reconstructive procedures with the use of prostheses, in many cases is still the best option in our experience.

Comparison of Cross-linked and Non-Cross-linked Acellular Porcine Dermal Scaffolds for Long-term Full-Thickness Hernia Repair in a Small Animal Model

BACKGROUND

This study compared the strength of incorporation and biocompatibility of 2 porcine-derived grafts (cross-linked and non-cross-linked) in a rat hernia model.

METHODS

A standardized 2 × 4 cm(2) fascial defect was created in 30 Wistar rats and repaired with either a cross-linked or a non-cross-linked graft. The rats were killed 3, 6, and 12 months later. The strength of incorporation, vascularization, cellular invasion, foreign body reaction, and capsule formation were evaluated.

RESULTS

Both graft materials showed cellular ingrowth and neovascularization by 3 months postimplantation. The average level of cellularization was significantly higher in the non-cross-linked grafts than in the cross-linked grafts at 6 months (2 vs 1; P = .029). Vascularization was significantly higher in the non-cross-linked grafts than in the cross-linked grafts at 6 months postimplantation (2 vs 1; P = .029) and insignificant at 3 months (2 vs 1.75; P = .311) and 12 months (1 vs 0.67; P = 1). The maximum load and breaking strength of both biomaterials increased during the study period. Overall, the strength of incorporation of the non-cross-linked grafts increased from 3 months (0.75 MPa) to 12 months (3.06 MPa) postimplantation. The strength of incorporation of the cross-linked grafts also increased from 3 months (0.59 MPa) to 12 months (1.58 MPa) postimplantation.

CONCLUSIONS

The results of our study suggest that non-cross-linked grafts may be slightly more biocompatible and allow a more rapid and higher degree of cellular penetration and vascularization, resulting in stronger attachment to the tissues.

Centrifugation versus PureGraft for fatgrafting to the breast after breast-conserving therapy

Background

Breast-conserving treatment (BCT) leads to a progressive and deteriorating breast deformity. Fatgrafting is ideal for breast reconstruction after BCT. The most frequently utilized technique for fat processing is centrifugation. The PureGraft device (Cytori Therapeutics, San Diego, CA, USA) is a new method that involves washing and filtering the fat to prepare the graft. We compared the subjective and objective outcomes of two fat-processing methods, centrifugation and PureGraft filtration.

Methods

Thirty patients underwent breast reconstruction performed by a single surgeon (OM) after BCT in our department between April 2011 and September 2012. The patients were preoperatively divided into two groups randomly: 15 received fatgrafts processed by centrifugation, and 15 received fatgrafts processed by washing in PureGraft bags. The patients were followed up for 12 to 30 months. To measure the subjective outcome, we distributed the BREAST-Q questionnaire to all the patients both preoperatively and 1 year postoperatively. The BCCT.core software evaluated the objective outcome of breast reconstruction by fatgrafting.

Results

The Breast-Q results indicated a tremendous improvement in the modules “Satisfaction with Breast” and “Psychosocial Well-being”. The “Sexual Well-being” scale also improved. Only the module “Satisfaction with Breasts” significantly differed between groups; patients treated with the PureGraft fat exhibited better outcomes. The BCCT.core results did not significantly differ between the groups.

Conclusion

One year postoperatively, the outcomes of the use of PureGraft bags or centrifugation to process fat for breast reconstruction after BCT did not differ. The unpredictability of the results following fatgrafting procedures is likely due to interindividual differences with yet-undisclosed causes.

NMR Studies on Intercalation Compounds of Layered Chalcogenides with Methylamines and Ammonia

NMR wideline and pulse techniques have been used to study orientation and molecular motions of the intercalation compounds of niobium disulfide with monolayers of mono-, di-, and trimethylamine, tetramethylammonium and ammonia. Specific information has been obtained from the 1H and 2D spectra and from spin-lattice relaxation measurements of the selectively deuterated monomethylamines. Models for the arrangement of the various molecules within the layers and for the motions have been derived. One-dimensional rotation of CH3 and NH3 groups, rapid intermolecular exchange of NH, NH2 and NH3 protons, as well as translational and reorientational motions of whole molecules are of importance. Interpretation of spin-lattice relaxation rates at various temperatures and frequencies yields details of some of these motion and numerical values for the activation energies.

The history and safety of breast implants

Breast implants are medical devices used for augmentation of the breast, to reconstruct the breast after mastectomy and to correct breast asymmetry. The breast prostheses are likely the most frequently used medical implants. The evolution of modern silicone breast implants was not straightforward and is characterised with a lot of medical, forensic and public attention. Currently it is sufficiently established that implants are safe and can be used for breast reconstruction and aesthetic augmentation. Prosthesis can rupture and produce local symptoms but there is no evidence that silicone breast implants can be of any health hazards for the patients.

Pectoral muscle flap with V-Y skin paddle for covering sternal defects

Deep sternal wound infection (DSWI) after a cardiac operation is a rare but serious complication associated with significant morbidity and mortality. It can lead to wound dehiscence with sternal osteomyelitis and both bony and soft tissue residual defects. When the infection is eradicated, reconstruction of the thoracic wall remains the main challenge. Tissue used for covering the defect must be well nourished and sutures must be tension free. We present our unique modification of the method using the pectoral muscle axial flap with a V-Y skin paddle.

Merkel cell carcinoma. Case report

BACKGROUND

Merkel cell carcinoma (MCC) is a rare aggressive skin tumour affecting mainly older and immuno suppressed individuals (see our review on MCC in this volume).

AIM

This is a case report describing our first experience with Merkel cell carcinoma in an elderly woman on chemo therapy for lymphoma and it covers the diagnosis, treatment and outcome.

METHODS

We did a radical excision of the soft tissue in the tumor area in conjunction with total paroditectomy and resection of the body of the zygomatic bone by radical block neck dissection. The skin defect was reconstructed myocutaneous free flap by a plastic surgeon.

RESULTS AND CONCLUSION

At 12 months follow-up, the MCC had not recurred.

Merkel cell carcinoma. A review

BACKGROUND

Merkel cell carcinoma (MCC) is a rare potentially fatal skin tumour affecting older mainly white people and younger immunosuppressed individuals. While uncommon, the incidence is increasing relative to melanoma and with twice the lethality. The benign appearance of the tumour usually on exposed skin parts, contrasting with its extensive microscopic invasion, can delay timely diagnosis. Recurrent MCC is currently attributed to the recently discovered Merkel cell polyomavirus This brief review of MCC covers the history, epidemiology,etiology,clinical and histological features, treatment and prognosis.

METHODS

Literature search using PubMed and search words Merkel cell carcinoma (MCC), etiology, treatment for the years 1972 to 2010.

RESULTS AND CONCLUSION

Merkel cell carcinoma is a rare malignancy with uncertain prognosis. Due to the uncommon occurrence and dearth of randomized studies, there is no agreement on optimal treatment. The tumor has only recently been included in the international classification of tumors (NCCN). The treatment approaches found to be best are radical surgery of primary tumor, drainage of lymph node extension and possibly adjuvant loco-regional radiotherapy. The basis of successful treatment however, remains prevention regular dermatological examination in immunosuppressed patients and early initiation of combination therapy, based on radical surgery supplemented by radiotherapy and palliative chemotherapy in the last resort.

Use of allogenous bone graft and osteosynthetic stabilization in treatment of massive post-sternotomy defects

Thoracic stabilization using transverse plate fixation represents a modern and safe method of sternal dehiscence treatment. However, it still remains difficult to apply in cases of massive loss of bone tissue of the chest wall. An unsatisfactory stability of thorax often results in severe respiratory insufficiency, and also affects healing of soft tissue closure while increasing the risk of development of chronic fistulas and other dehiscences. In the reported case, we opted for a unique treatment of massive post-sternotomy defect using an allogenous bone graft of calva. Transverse titanium plates were applied to achieve stabilization of bone grafts and chest wall.

Superiority of topical negative pressure over closed irrigation therapy of deep sternal wound infection in cardiac surgery

AIM

We sought to compare clinical outcomes, in-hospital mortality and 1-year survival of two different treatment modalities of deep sternal wound infection, topical negative pressure and the closed irrigation therapy.

METHODS

Retrospective analysis of 66 consecutive patients treated for deep sternal infection at our institution. A total of 28 patients (February 2002 through September 2004) underwent primarily closed irrigation therapy, and 34 patients (November 2004 through December 2007) had the application of topical negative pressure. Four patients (July 2004 through December 2004) who underwent a combination of both strategies were excluded from the study. Clinical and wound care outcomes were compared, focusing on therapeutic failure rate, in-hospital stay and the 1-year mortality of both treatment strategies.

RESULTS

Topical negative pressure was associated with a significantly lower failure rate of the primary therapy (P<0.05), shortening of the intensive care unit stay (P<0.001), a particular decrease in the in-hospital stay (P<0.05) and the 1-year mortality (P<0.05) in comparison with closed irrigation therapy. Comparable overall length of the therapy, in-hospital stay and the risk of wire-related fistulas after chest reconstruction were found.

CONCLUSION

Topical negative pressure is a superior method of treatment for deep sternal wound infection, which is based on lower therapeutic failure rate, significant decrease in-hospital stay, and the decrease of the 1-year mortality rate, compared with primarily applied closed irrigation.