The role of tissue expansion in reconstructive surgery.
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Dermatologic Surgical Procedures↗
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The use of soft tissue expansion in reconstructive surgery.
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Adolescent↗
Tissue expansion: "future of plastic surgery for next 20 years'.
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Elasticity↗
Effect of human fibroblast-derived dermis on expansion of tissue from venous leg ulcers.
Novel approaches to healing of chronic wounds, such as venous leg ulcers, include the use of tissue-engineered skin substitutes, e.g., human fibroblast-derived dermis. The exact mechanisms of action of these products and their effects on wound healing at a cellular level are yet to be fully defined. The aim of our study was to evaluate the potential effects of human fibroblast-derived dermis on the healing of chronic wounds using an experimental model. We used a tissue expansion model to examine the effect of human fibroblast-derived dermis on the growth of human tissue biopsied from venous leg ulcers. Further characterization of the cytokine profile produced by human fibroblast-derived dermis in culture was performed using enzyme-linked immunosorbent assay techniques. Addition of medium conditioned with human fibroblast-derived dermis significantly increased the outgrowth of cells from venous leg ulcer biopsies (p = 0.001). We detected bioactive levels of hepatocyte growth factor/scatter factor and interleukin-8 in media conditioned with human fibroblast-derived dermis. Therefore, conditioned media from human fibroblast-derived dermis enhances ex vivo expansion of tissue taken from chronic venous leg ulcers, and contains potent angiogenic factors. These experimental findings may explain the enhanced healing seen with clinical applications of human fibroblast-derived dermis on chronic wounds.
Cell Culture Techniques↗
Scar-length reduction by ring-shaped expansion.
Conventional tissue expansion with rectangular or round expanders often results in considerable dog-ear formation and, after resection, in lengthening of the final scar. The resulting scar is, always much longer than the maximal diameter of the skin lesion. These disadvantages are partially avoided by the use of croissant-shaped expanders. Taking the idea of the croissant-shaped expander and thinking further in terms of differential expansion, a new expander has been designed. It consists of a ring-shaped expander that is placed under the normal skin around the lesion. When the appropriate expansion is reached, the skin lesion is excised and the defect is closed with a running subcuticular suture, pulling as much skin as possible centripetally. The resulting scar is shorter than the maximal diameter of the skin lesion. The new expander has been tested in two patients in regions that are reputed for poor scar quality (the back and the upper arm). The results are encouraging.
Adult↗
Continuous versus intraoperative expansion in the pig model.
Continuous tissue expansion utilizing a continuous infusion device that maintains a constant expander pressure was previously demonstrated to be feasible and successful in obtaining rapid tissue expansion in a canine model. Intraoperative tissue expansion has been described and has gained some clinical acceptance as a method to gain rapid expansion. We compared the efficacy of continuous tissue expansion versus intraoperative tissue expansion in a piglet model. After completing a pilot study, continuous tissue expansion was performed in six pigs (14.5 to 20 kg) on one flank over a 3-day period utilizing an improved prototype device; at the termination of continuous tissue expansion, intraoperative tissue expansion was performed on the opposite flank. There were no complications or continuous tissue expansion device malfunctions. Intraoperative tissue expansion gave a true gain in area of 7.4 percent, while continuous tissue expansion produced a 22 percent gain (p < 0.02). When the effects of both recruitment and expansion were added, continuous tissue expansion gave a dividend of 286 percent versus 192 percent for intraoperative tissue expansion (p < 0.01). Biomechanically, intraoperative tissue expansion skin showed few differences from unexpanded skin, while continuous tissue expansion skin showed a significant increase in stress relaxation (47.78 versus 38.74) and decrease in breaking strength. Histologic analysis revealed some epidermal hyperplasia and inflammation surrounding the continuous tissue expansion expander and some vascular congestion over the intraoperative tissue expansion expander. We conclude that continuous tissue expansion is superior to intraoperative tissue expansion and that the prototype device may be useful clinically.
Animals↗
Giant congenital melanocytic nevi of the trunk and an algorithm for treatment.
Giant congenital melanocytic nevi (CMN) are rare, congenital, disfiguring lesions with a risk of degeneration to malignant melanoma. Giant CMN are associated with an increased risk of malignant degeneration. In a minority of cases, patients with giant CMN may have associated neurocutaneous melanosis with leptomeningeal involvement. Giant CMN of the trunk pose difficult diagnostic and reconstructive problems requiring complex multistage treatment. For high-risk cases, diagnostic evaluation in the form of neuro-imaging is an essential component of the planning phase. Although nonsurgical options for the treatment of giant CMN have been advocated, these modalities may decrease the burden of nevus cells but do not result in complete removal of these cells. The ability to monitor nevus cells that remain after nonsurgical management of giant CMN remains questionable. These nonsurgical options include dermabrasion, laser ablation, and chemical peel. In contrast, direct excision of the nevus is the mainstay of treatment of nonsurgical management of giant CMN. There are numerous surgical options to resurface the resultant cutaneous defect after excision of the nevus. The simplest of these options consists of serial excision and direct closure of the defect in stages. However, if the defect cannot be closed by direct cutaneous advancement, other options for wound resurfacing include split- or full-thickness skin graft, tissue expansion, and free tissue transfer. Tissue expansion should be viewed as a category of treatment options because expanders can be used to create an expanded full-thickness skin graft, local expanded flaps adjacent to the lesion, or expansion of a free tissue donor site. Given the diversity of reconstructive options that use tissue expansion, these techniques have evolved as the primary treatment method for giant CMN of the trunk. The authors outline an approach to the evaluation of giant CMN of the trunk, review the risks of melanoma and of neurocutaneous melanosis, describe their preferred treatment regimen, and offer a treatment algorithm for giant CMN of the trunk.
Algorithms↗
Reconstruction of acquired scalp defects: an algorithmic approach.
LEARNING OBJECTIVES: After studying this article, the participant should: 1. Understand scalp anatomy, hair physiology, and skin viscoelastic properties as they relate to scalp reconstruction. 2. Understand the principles that allow for aesthetic reconstruction of scalp defects. 3. Understand the use of local tissue rearrangement for reconstruction of specific areas of the scalp. 4. Understand the use of tissue expansion and free tissue transfer for scalp reconstruction. BACKGROUND: Reconstruction of scalp defects is required for acute trauma, tumor extirpation, radiation necrosis, and the repair of traumatic alopecia or cosmetically displeasing scars. METHODS: The proper choice of a reconstructive technique is affected by several factors-the size and location of the defect, the presence or absence of periosteum, the quality of surrounding scalp tissue, the presence or absence of hair, location of the hairline, and patient comorbidities. Successful reconstruction of these defects requires a detailed knowledge of scalp anatomy, hair physiology, skin biomechanics, and the variety of possible local tissue rearrangements. In nearly total defects, local tissues may be inadequate and tissue expansion or free tissue transfer may be the only alternatives. RESULTS: Plastic surgeons are now able to obtain coverage over the calvaria after the most devastating of defects; however, the challenge to the reconstructive surgeon today is to do so with excellent cosmetic results. Cosmetic scalp reconstruction requires restoration and preservation of normal hair patterns and hair lines. CONCLUSIONS: Successful reconstruction of the scalp requires careful preoperative planning and precise intraoperative execution. Detailed knowledge of scalp anatomy, skin biomechanics, hair physiology, and the variety of available local tissue rearrangements allows for excellent aesthetic reconstruction.
Algorithms↗
A PIF-regulated switch in cell axis growth drives cotyledon expansion through tissue-specific cell expansion and division.
Despite its crucial role during seedling deetiolation, cotyledon expansion has been largely overlooked, with hypocotyl elongation favored as the primary phenotypic readout in light signaling research. Here, we investigate how cotyledon expansion is regulated during seedling establishment and reveal that light-induced cotyledon expansion involves a rapid switch in growth direction - from longitudinal in darkness to transversal upon initial light exposure. Using PIFq- and phyA/phyB-deficient Arabidopsis mutants, we demonstrate that this switch is repressed by PIFs in the dark and promoted by phytochromes under red light. Notably, expansion is antagonistically regulated in the light by GUN1-mediated plastid retrograde signaling. Cotyledon expansion involves rapid epidermis cell expansion, transitioning from rectangular in darkness to characteristic lobed cells in light. Importantly, our findings show that mesophyll extension is driven not only by cell enlargement but also by palisade cell division, consistent with an enrichment of cell cycle-related genes that are antagonistically regulated by the PIF/phy system and retrograde signaling in the cotyledon. Finally, using mutant lines expressing PIF1 and phyB specifically in the epidermis, we establish that epidermal expansion can drive palisade cell growth, while mesophyll cell division is predominantly regulated by light at the tissue-specific level. This study provides a novel framework for investigating cotyledon expansion during seedling deetiolation, incorporating tissue-level regulation. We propose that cotyledons serve as an excellent model for studying morphogenesis and organ geometry, which in plants is governed by directional cell growth.
Cotyledon↗
Tissue expansion-assisted prefabrication of the forehead flap for nasal reconstruction.
A new technique for nasal reconstruction is described. This method--expansion-assisted flap prefabrication--is essentially a simultaneous application of pretransfer grafting and tissue-expansion procedures for creating custom-made forehead flaps to meet varying requirements of nasal reconstruction. We have applied this new technique on seven patients, with full-thickness nasal defects during a 3-year period. Results from these patients are presented with a review of different use of flap prefabrication principles in nasal reconstruction.
Adolescent↗
Reconstruction of composite facial defects: the combined application of multiple reconstructive modalities.
OBJECTIVE: To describe the combined use of craniofacial skeletal reconstruction, tissue expansion and microvascular free tissue transfer in the repair of major composite facial defects. DESIGN: Case series with an integrated team approach. SETTING: Craniofacial unit, university teaching hospital. PATIENTS: Three cases were selected to best illustrate the combined use of the three modalities in reconstruction of acute traumatic, congenital and post-traumatic facial defects. A 15-year-old boy had a shotgun wound to the face; a 23-year-old man had Treacher Collins syndrome; and a 55-year-old woman had a post-traumatic composite defect of the central midface. INTERVENTIONS: Preoperatively, complete neurologic, ophthalmologic and dental examinations, anthropometric analysis, prosthodontic assessment, computed tomography and computer graphics. Operatively, craniofacial exposure followed established surgical principles. Skeletal reconstruction was performed to provide accurate positioning of bony segments and three-dimensional stability. Bone grafting was used when necessary to restore bony continuity and increase stability. Tissue expansion was used to provide more locally available tissue for wound closure and resurfacing composite defects. Microsurgical free tissue transfer was used to provide functional replacement of deficient tissues. RESULTS: The results of the modalities used for reconstruction of these composite facial defects are illustrated for each case described. CONCLUSIONS: The use of multiple modalities, including craniofacial skeletal reconstruction, tissue expansion and free tissue transfer, allow the surgeon to address the specific functional and anatomical requirements associated with composite facial defects that are characterized by a combined deficiency of multiple tissues in the craniofacial region.
Adolescent↗
[Preliminary experimental study on free radicals in expanded soft tissue].
OBJECTIVE: To inquire into the formation of free radicals during tissue expansion and its influence on tissue expansion. METHOD: Expanders of 20 ml were placed beneath the dorsal skin of SD rats, and the conventional expansion course took about 23 to 25 days. The activity of SOD and the content of MDA in skin were determined prior to the last expansion, 1 h, 6 h, 12 h and 24 h after the last expansion, respectively. Meanwhile, the effect of SOD on expansion area and length was observed. RESULT: The activity of SOD and the content of MDA at 1 h, 6 h, and 12 h after expansion were significantly different from those before expansion, while the activity of SOD and the content of MDA at 24 h after expansion were almost the same as those before expansion. The difference of expansion area and length between SOD and NS groups was significant, especially during 16 to 24 days. CONCLUSION: Tissue expansion produces free radicals and SOD can increase expansion area and length. The study provides a clue to find a way for safe, rapid and effective soft tissue expansion.
Animals↗
Expansion of fascial flaps: histopathologic changes and clinical benefits.
In order to meet the requirements of large defects created by sacral and trochanteric pressure ulcers, tensor fasciae latae and lumbosacral fasciocutaneous flaps were expanded with a silicone expander in six patients (10 flaps). In 8 of the flaps the location of pressure ulcers was trochanteric, and in 2 it was sacral. In each case the period of expansion was 4 weeks. Histopathologic examination after expansion showed an increase in the vascularity and overall thickness of fascia in both types of flaps. After 4 weeks of expansion, the perifascial areolar tissue was replaced with thick granulation tissue in the tensor fasciae latae flaps. This markedly vascular layer of granulation tissue interposed between the fasciae and the subcutaneous tissue augmented the internal matrix of the flap, thereby lowering the potential for shearing during flap elevation. Conceivably, owing to the absence of an areolar tissue layer in the lumbosacral fasciocutaneous flaps, no layer of granulation tissue was observed. The average thickness of the fibrous capsule formed around the expanders was 573.2 microns, which was composed of three structurally different zones. Prior tissue expansion obviously assisted primary closure of the flap donor site. In addition, it seems that the tissue-expansion process rendered the distal portion of fascial flaps more robust because of increased vascularity. It is therefore proposed that preparatory tissue expansion of fascial flaps has several advantages. The obvious benefits include the ability to close larger defects while closing the donor site primarily. As a result of this study, the additional benefits may include a reduction in the mechanical shear potential of these flaps and an improvement in their vascularity.
Adipose Tissue↗
The histopathological changes in irradiated vs. nonradiated tissue-expanded skin in the porcine model.
This study examined the histological changes following irradiation on nonexpanded and tissue-expanded pigskin. Six Yorkshire pigs received 4860 cGy radiation to one flank with the opposite side serving as the control. A histopathological comparison of tissue expansion in irradiated tissue to nonradiated tissue showed a reduction in the thickness of the dermal and subcutaneous layers, with less prominent rete ridges and a thicker stratum spinosum (p < 0.05). Nonexpanded irradiated tissue showed a reduction of thickness in the dermis and subcutaneous layer, less prominent rete ridges, and a thicker stratum spinosum layer (p < 0.05) when compared with nonradiated tissue. Tissue-expanded irradiated tissue showed no significant differences (p > 0.05) in any of these parameters when compared with nonexpanded irradiated tissue. This study demonstrates that radiation produced a significant change in porcine skin, but tissue expansion did not further alter the histological changes associated with irradiation.
Animals↗
Repair of scalp defects using a tissue expander and Marlex mesh.
A simple technique using Marlex mesh and a tissue expander to cover scalp defects is described and two patients are presented. This technique is suitable for medium-sized defects that cannot be closed primarily. Marlex mesh is sutured to the wound edges in lieu of a temporary skin graft and to prevent enlargement of the defect during tissue expansion. The tissue expander is placed under adjacent normal scalp in a subgaleal pocket developed through the scalp defect. The scalp defect is closed secondarily using the expanded scalp flap. This technique was performed in two patients with satisfactory results. Marlex mesh obviates the need for a temporary skin graft to cover the scalp defect.
Adult↗
Concepts in scalp and forehead reconstruction.
Reconstruction of forehead and scalp defects are challenging. A thorough understanding of the anatomy and dissection planes of the scalp is essential. The ability to use a variety of techniques allows the facial plastic surgeon to maximize functional and aesthetic results. Techniques such as tissue expansion, free tissue transfer, and flaps used for covering exposed bone are useful adjuncts for optimal results.
Alopecia↗
[Investigation on contraction mechanism of expanded tissue].
OBJECTIVE: To investigate the contraction mechanism of expanded tissue. METHODS: White domestic pigs were employed to establish tissue expansion model. Tissue samples were taken after expansion for contraction measurements and histopathological observation. RESULTS: Dermis and capsule were the main positions of contraction. In the dermal layer, elastic fibers and myofibroblasts proliferated greatly and alpha-Actin enhanced in the myoepidermal cells and capillary endothelial cells during expansion. In the capsule, the direction of elastic and collagen fibers arranged crossly and formed into special contractible structure. CONCLUSION: Elastic fibers, myofibroblasts and alpha-Actin enhancement of cells were the substantial materials of tissue contracture increases. The results suggest that suitable tension must be applied into expanded flaps for anti-contraction.
Animals↗