|
|
| Line 1: |
Line 1: |
| {{Blacklisted-links|1=
| | Aleta is what's written on her birth certificate though she doesn't really appreciate being called like which experts claim. Managing people is regarded as what she does although she plans on changing it. She's always loved living into South Carolina. To hard disk drive is something her [http://www.reddit.com/r/howto/search?q=hubby+doesn%27t hubby doesn't] really like yet , she does. She is running and attempting to keep a blog here: http://prometeu.net<br><br>my page hack clash of clans ([http://prometeu.net look at more info]) |
| *http://www.norm.org/joy.html
| |
| *:''Triggered by <code>\bnorm\.org\b</code> on the local blacklist''|bot=Cyberbot II}}
| |
| {{Interventions infobox |
| |
| Name = Tissue expansion |
| |
| Image = |
| |
| Caption = |
| |
| ICD10 = |
| |
| ICD9 = |
| |
| ICD9_mult = |
| |
| MeshID = D015626 |
| |
| OPS301 = |
| |
| OtherCodes = |
| |
| }}
| |
| [[File:Skin and tissue expander device.jpg|thumb|right|Skin and tissue expander with inflatable balloon device]]
| |
| '''Tissue expansion''' is a technique used by [[plastic surgery|plastic]] and restorative [[surgery|surgeon]]s to cause the body to grow additional [[skin]], [[bone]] or other tissues. Other biological phenomena such as tissue inflammation can also be considered expansion (see tissue inflammation below).
| |
| | |
| ==Skin expansion==
| |
| [[Image:Tissue expander diagram.jpg|thumb|Skin expansion using a subcutaneous inflatable balloon]]
| |
| Skin expansion is a common surgical procedure to grow extra skin through controlled mechanical overstretch.It creates skin that matches the color, texture, and thickness of the surrounding tissue, while minimizing scars and risk of rejection.<ref>{{cite journal |doi=10.1007/s10237-011-0357-4 |title=Growing skin: Tissue expansion in pediatric forehead reconstruction |year=2011 |last1=Zöllner |first1=Alexander M. |last2=Buganza Tepole |first2=Adrian |last3=Gosain |first3=Arun K. |last4=Kuhl |first4=Ellen |journal=Biomechanics and Modeling in Mechanobiology}}</ref>
| |
| | |
| When skin is stretched beyond its physiological limit, [[mechanotransduction]] pathways are activated. This leads to [[cell (biology)|cell]] growth as well as to the formation of new cells. In some cases, this may be accomplished by the implantation of inflatable balloons under the skin (see figure). By far the most common method, the surgeon inserts the inflatable expander beneath the skin and periodically, over weeks or months, injects a [[saline (medicine)|saline]] solution to slowly stretch the overlaying skin. The growth of tissue is permanent, but will retract to some degree when the expander is removed.<ref>{{cite journal |pmid=13419574 |year=1957 |last1=Neumann |first1=CG |title=The expansion of an area of skin by progressive distention of a subcutaneous balloon; use of the method for securing skin for subtotal reconstruction of the ear |volume=19 |issue=2 |pages=124–30 |journal=Plastic and Reconstructive Surgery}}</ref> Topically applied tissue expansion devices also exist. These have the benefit of being inexpensive and do not require a surgical procedure to implant them under the skin.<ref name="Pmid">{{cite journal |pages=345–51 |doi=10.1111/j.1749-4486.2011.02354.x |title=Cost-effectiveness of a topically applied pre-operative tissue expansion device for radial forearm free flaps: A cohort study1 |year=2011 |last1=Bonaparte |first1=J.P. |last2=Corsten |first2=M. |last3=Allen |first3=M. |journal=Clinical Otolaryngology |volume=36 |issue=4 |pmid=21651729}}</ref>
| |
| | |
| [[Breast reconstruction]] surgery, for example, can use this technique when the [[mammary gland]] was removed by surgery ([[mastectomy]]). Later, a more permanent breast implant filled with saline or silicone gel is inserted under the expanded skin pocket.{{Citation needed|date=January 2012}}
| |
| | |
| In other applications, excess skin is grown purposely by expansion on the back or the buttocks, so that it can be harvested later for [[Organ transplant|transplantation]] to another site where skin was lost due to [[Physical trauma|trauma]], extensive [[wound]]s, [[surgery]], [[burn (injury)|burns]], etc.
| |
| | |
| Tissue expansion has also been used for the technique of [[foreskin restoration]], which is usually non-surgical and applies tension externally using specialized devices to replace circumcised tissues with new cells.<ref>{{cite journal |pmid=6484035 |year=1984 |last1=Radovan |first1=C |title=Tissue expansion in soft-tissue reconstruction |volume=74 |issue=4 |pages=482–92 |journal=Plastic and reconstructive surgery |doi=10.1097/00006534-198410000-00005}}</ref>
| |
| | |
| === Mechanics of skin expansion ===
| |
| | |
| Stretching the skin beyond normal expansion invokes several mechanotransduction pathways which increase mitotic activity and promote collagen synthesis. As a result, the skin surface area increases. Continuum mechanics approaches can be used to model skin growth during tissue expansion and non-linear finite element methods can be used to computationally simulate different tissue growth scenarios.<ref name="ReferenceA">{{cite journal |doi=10.1016/j.jtbi.2011.12.022 |title=On the biomechanics and mechanobiology of growing skin |year=2012 |last1=Zöllner |first1=Alexander M. |last2=Buganza Tepole |first2=Adrian |last3=Kuhl |first3=Ellen |journal=Theoretical Biology}}</ref>
| |
| | |
| Tissue growth due to skin expansion can be modeled as anisotropic surface area growth as described by the following equations:
| |
| | |
| <math>F = F^e \cdot F^g\,</math>
| |
| | |
| where <math>F^e</math> is elastic area stretch that is reversible and <math>F^g</math> is irreversible area growth described by:
| |
| | |
| <math>F^g = \sqrt{\theta^{g}}\mathbb{I}+[1-\sqrt{\theta^{g}}]n_{0}\otimes n_{0} \,</math>
| |
| | |
| where <math>n_{0}</math> is a vector in the direction of skin thickness. We assume that the skin does not grow in the thickness direction for area growth is equal to volume growth or <math>\theta^{g} = det(F^{g}) = J^{g}</math>.<ref name="ReferenceA"/>
| |
| We also assume that the newly created skin will have the same density, stiffness, and microstructure as the original, non-expanded skin.
| |
| <ref>{{cite journal |doi=10.1007/s10237-011-0357-4 |title=Growing skin: Tissue expansion in pediatric forehead reconstruction |year=2011 |last1=Buganza Tepole |first1=Adrian |last2=Ploch |first2=Christopher Joseph |last3=Wong |first3=Jonathan |last4=Gosain |first4=Arun K. |last5=Kuhl |first5=Ellen |journal=Biomechanics and Modeling in Mechanobiology}}</ref>
| |
| | |
| ===Radial Forearm Free Flaps===
| |
| Recent studies have demonstrated that using topical tissue expansion can reduce the need for a split thickness skin graft after harvesting a forearm free flap.<ref>{{cite journal |pmid=21453657 |year=2011 |last1=Bonaparte |first1=JP |last2=Corsten |first2=MJ |last3=Allen |first3=M |title=Healing time of radial forearm free flap donor sites after preoperative tissue expansion: Randomized controlled trial |volume=40 Suppl 1 |pages=S20–7 |journal=Journal of Otolaryngology}}</ref> The authors noted that this results in less pain as well as reduced healing time. This method has also been shown to be cost effective<ref name="Pmid" /> as well as improve cosmetics.{{Citation needed|date=January 2012}}
| |
| | |
| ===For Foreskin Restoration===
| |
| Circumcised men can use non-surgical tissue expansion techniques to expand their surviving penile skin, making it a longer tube so it can function like a [[foreskin]].<ref>{{cite book|url=http://www.norm.org/joy.html|title=The Joy of Uncircumcising|publisher=Hourglass Book Pub|date=1 September 1994 | accessdate=2011-10-17}}{{Page needed|date=January 2012}}{{Unreliable medical source|date=January 2012}}</ref> Methods may involve securing a tension strap or weight to the skin with tape, or gripping the skin with a tapeless foreskin [[restoration device]] that uses straps, or weights, or tension derived from internal expansion of the device. Some men succeed by tugging on the penile skin regularly with their fingers. The total time commitment to go from circumcised to an uncircumcised man's appearance and function might be 2 to 4 years (or more, depending on the severity of the [[circumcision]]) while tugging up to 12 hours per day. A foreskin restorer does not usually involve his doctor in the process.{{Citation needed|date=January 2012}}
| |
| | |
| ===In scalp reconstruction===
| |
| Tissue expansion has been used on the scalp for treating scalp scarring, in lieu of hair transplation when there is insufficient donor hair to transplant on the scar or the scar tissue is not vascularized to support hair growth. For instance, in a patient who had [[melanomas]] removed from the scalp resulting in [[alopecia]] defects (hair loss), tissue expansion can be used to allow for the removal of scars and complete hair coverage. The two main indications for choosing tissue expansion over hair grafting are the size and shape of the defect relative to potential supply of donor hair, and the quality and thickness of the scar tissue. Areas of significant scarring and/or tissue atrophy, which is likely to make hair grafting unsuccessful, are best excised and replaced by normal expanded scalp skin. Theoretically, there is no limit to the amount of tissue that can be created with tissue expansion, provided the process is conducted gradually.<ref>Hair Transplant Forum International, Sept/Oct 2006, [http://www.FoundHair.com/media/scalp-reconstruction.pdf Scalp Reconstruction: The Role of Tissue Expansion]{{Unreliable medical source|date=January 2012}}</ref>
| |
| | |
| ==Bone expansion== | |
| {{main|Distraction osteogenesis}}
| |
| [[Bone]] is another tissue that can be expanded relatively easily, by using external devices which are slowly separated using mechanical contraptions, so that bone grows in response to elongation ([[bone distractor]]). Other techniques and external devices have been studied and have shown some success, such as in the [[fitbone surgery]].<ref>{{cite journal |pages=193–6 |doi=10.1007/s00595-003-2667-3 |title=External Tissue Expansion Successfully Achieved Using Negative Pressure |year=2004 |last1=Lasheen |first1=Ahmed E. |last2=Salim |first2=Aiman |last3=Hefny |first3=Mohamad R. |last4=Al-Bakly |first4=Esam |journal=Surgery Today |volume=34 |issue=2 |pmid=14745629}}</ref> This technique was pioneered in 1951 by the [[Russia]]n [[physician]] [[Gavril Ilizarov|Ilizarov]], and is called the [[Ilizarov apparatus]]. It is capable of lengthening limbs in cases of pathological loss of bone, asymmetry of limbs, [[dwarfism]], short stature, etc. In reconstructive and cosmetic surgery, bone expanders have been used to elongate the [[Human mandible|mandibula]] in cases of [[congenital disorder]]s, [[Physical trauma|trauma]], [[tumor]]s, etc. Other newer devices such as the [[orthofix]] and [[intramedullary skeletal kinetic distractor]] (ISKD) are also used for limb lengthening. It can add over 6 inches per bone, but is expensive, painful, and time-consuming (each procedure lasts around 8–12 months).{{Citation needed|date=January 2012}}
| |
| | |
| ==Tissue Inflammation==
| |
| Inflammation, in the biological sense, refers to the cellular response of the body to disturbances, be they internal or external. In the case of [[asthma]] or [[chronic bronchitis]] the human body responds to allergens or pollutants by flooding the bronchial tree and airway walls with mononuclear cells. The layers of the airway wall, including the inner epithelial tissue lining thickens and expands anywhere from 10% to 300% of healthy individuals, and obstructs air flow.<ref>{{cite journal|last=Cohn|first=Lauren|coauthors=Elias, Jack A.; Chupp, Geoffrey L.|title=A : Mechanisms of Disease Persistence and Progression|journal=Annual Review of Immunology|date=1 April 2004|volume=22|issue=1|pages=789–815|doi=10.1146/annurev.immunol.22.012703.104716}}</ref> Enduring the disease long term coupled with airway hyperresponsiveness (smooth muscle contraction or [[Bronchial hyperresponsiveness]]) leads to chronic continuous inflammation and thickening, and noticeable airway remodeling consisting of stiffer airways and lost elasticity.<ref>{{cite journal|last=Brackel|first=HJ|coauthors=Pedersen, OF; Mulder, PG; Overbeek, SE; Kerrebijn, KF; Bogaard, JM|title=Central airways behave more stiffly during forced expiration in patients with asthma.|journal=American journal of respiratory and critical care medicine|date=September 2000|volume=162|issue=3 Pt 1|pages=896–904|pmid=10988102}}</ref> Inflammation in a constricted cylinder, as with an airway, eventually folds over on itself, leading to mechanically studied buckling patterns and growth relationships within tissue linings.<ref>{{cite journal|url=Wiggs, Barry R et al. “On the Mechanism of Mucosal Folding in Normal and Asthmatic Airways On the Mechanism of Mucosal Folding in Normal and Asthmatic Airways.” (2013): 1814–1821. Print.}}</ref><ref>{{cite journal|url=Moulton, D E, and A Goriely. “Possible Role of Differential Growth in Airway Wall Remodeling in Asthma Possible Role of Differential Growth in Airway Wall Remodeling in Asthma.” January 2011 (2012): 1003–1012.}}</ref>
| |
| | |
| ==Breast tissue expansion==
| |
| Tissue expansion is a common technique used for [[breast reconstruction]].<ref>{{cite journal | pages=11(2),257–64|title=Reconstruction of the breast by tissue expansion.|year=1984| last1 =Argenta |first1 =LC.|journal = Clinics in Surgery| pmid=6723196| volume=11| issue=2}}</ref> This essentially involves expansion of the breast skin and muscle using a temporary [[tissue expander]].<ref>{{cite journal | pages = 195–208| title=Breast reconstruction after mastectomy using the temporary expander |year=1982| last1 = Rodovan |first1 =C.|journal = Plastic and Reconstructive Surgery| pmid=7054790 | volume=69 | issue=2}}</ref> Three to four weeks after the [[mastectomy]],<ref>{{cite web|title=http://en.wikipedia.org/wiki/Mastectomy}}</ref> a salted solution will be injected into the expander to gradually fill it. This process is supported by a tiny valve mechanism located inside the expander and it will continue until its size is slightly larger than the other breast. Typically it can take several weeks to months to complete the process. This tissue expander is removed after a few months and microvascular flap reconstruction or the insertion of a permanent breast implant is done at the time. Chemotherapy or radiation is sometimes recommended by the medical/radiation oncologist following mastectomy. These treatments delay the tissue expansion process by approximately four to eight weeks.Tissue expanders have silicone outer shells and either an internal valve or external port to allow for saline fluid injections.
| |
| | |
| ==Alternatives to Skin Expansion==
| |
| Research dedicated to alternative skin grafts is currently within the purview of tissue engineering. Multiple engineered tissue-derived and tissue-like substances have made it through the FDA and into the market, though financial success has been moderate.<ref>Advanced Tissue Sciences Inc.: learning from the past, a case study for regenerative medicine.</ref> Limitations of this strategy include long incubation times, as well as difficulty in mimicking that exact mechanical and biological properties of functional skin.<ref>Tissue engineering of replacement skin: the crossroads of biomaterials, wound healing, embryonic development, stem cells and regeneration</ref> However, benefits range from decreased donor site morbidity (as a result of no longer needing to harvest from skin expansion) as well as a ready-available source of materials for emergency medicine in the case of traumatic burn or injury. There remains much clinical interest today in developing inexpensive engineered skin grafts that possess the mechanical and biological properties of skin.
| |
| | |
| ==References==
| |
| {{reflist}}
| |
| | |
| ==External links==
| |
| *[http://www.vardaan.net/ilizarov.htm Ilizarov apparatus].
| |
| *[http://www2.nidcr.nih.gov/iyf/skin.html About Faces: Skin]. NICDR National Institutes of Health on-line exhibit. Source of the images used.
| |
| *[http://www.foundhair.com Foundation for Hair Restoration]
| |
| | |
| [[Category:Orthopedic surgery]]
| |
| [[Category:Plastic surgery]]
| |
Aleta is what's written on her birth certificate though she doesn't really appreciate being called like which experts claim. Managing people is regarded as what she does although she plans on changing it. She's always loved living into South Carolina. To hard disk drive is something her hubby doesn't really like yet , she does. She is running and attempting to keep a blog here: http://prometeu.net
my page hack clash of clans (look at more info)