Commentary on: The Best Under Stress: An Analysis of Breast Tissue Expander Response to External Forces.
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ABSTRACT:
SUBMITTER: Nahabedian MY
PROVIDER: S-EPMC10265441 | biostudies-literature | 2023
REPOSITORIES: biostudies-literature
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Commentary on: The Best Under Stress: An Analysis of Breast Tissue Expander Response to External Forces.
Aesthetic surgery journal. Open forum 20230223
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Project description:BackgroundThe use of breast tissue expanders (TEs) in breast reconstruction is accompanied by undesired changes to the chest wall and lateral plane. Breast TEs are designed to create a naturally formed breast pocket by capitalizing on the ductile response of skin tissue; however, in practice, the use of expanders is accompanied by undesired changes to the chest wall and lateral plane.ObjectivesThe authors of this study compared 3 comparably sized and commercially available breast TEs to assess the mechanical profile and functionality of each design.MethodsAuthors compared MENTOR Artoura PLUS Smooth (Irvine, CA), Allergan 133 Smooth (Irvine, CA), and Sientra AlloX2 Smooth (Santa Barbara, CA) filled to 100% of their label volume. The mechanical profile of TEs was assessed via vertical compression. Dimensions were recorded at baseline and percent changes were calculated at each compressive load (5-35 lbf intervals of 5 lbf).ResultsBase width and projection were recorded at compressive loads of 10, 20, and 35 lbs. For percent changes of base width, MENTOR had 0.98%, 2.09%, 3.84%; Allergan 4.21%, 9.15%, 15.52%; and Sientra 4.72%, 10.19%, 19.15%. For percent changes of projection, MENTOR had -19.06%, -25.44%, -30.88%, Allergan -35.53%, -42.90%, -50.09%, and Sientra -29.64%, -37.68%, -44.69%. For percent change of height, MENTOR had 1.44%, 2.62%, 4.27%, Allergan 10.26%, 16.49%, 22.97%, and Sientra 6.99%, 11.93%, 16.90%. MENTOR's TE had the most pronounced lower pole with volume expansion.ConclusionsThe MENTOR TE demonstrated the least lateral deformation and projection loss across the range of compressive loads, as well as the highest force resistance compared with the other models.Level of evidence 3
| S-EPMC10063436 | biostudies-literature
Project description:Both internal and external tissue expanders take advantage of the innate adaptive mechanisms the skin exerts in response to mechanical tension, known as the stress-relaxation phenomenon. Internal tissue expander use is time-consuming and can be complicated by infection and extrusion. In this case series, continuous external tissue expanders used to manage large pediatric wounds were assessed. Fourteen patients (ages: 4 days to 17 years) with large wounds underwent continuous external tissue expansion intraoperatively. The success of wound closure was assessed. In addition, the size of the patient's wounds, duration of device application, and postoperative complications were evaluated. The continuous external tissue expander was applied to wound sizes ranging from 14.7 to 560 cm2 for 5 to 10 days until the wound was amenable for direct closure. In 11 of the 14 patients, delayed primary closure was achieved. The device significantly reduced the wound sizes of the remaining three cases (average 80% size reduction). There was no incidence of wound dehiscence or infection. This case series demonstrates the benefit of the continuous external tissue expansion in managing pediatric wounds that would not otherwise be amenable to primary closure. The method allows for timely closure with limited risk of infection or extrusion, and should be in the armamentarium of reconstructive plastic surgeons.
| S-EPMC8395595 | biostudies-literature
Project description:BackgroundWhile the number of implant-based immediate breast reconstructions has increased, two-stage reconstructions still comprise a significant proportion. Some studies have reported chest wall depression (CWD) following tissue expander insertion; however, there have been no reports on chest wall recoiling following expander removal. Here, we present a case of CWD resulting from tissue expander use for breast reconstruction, with subsequent chest wall recoiling following expander removal.Case descriptionA 40-year-old woman had previously undergone skin-sparing mastectomy and tissue expander insertion at another hospital 7 months previously. She presented to our institute and complained of pain and restricted shoulder movement, desiring the removal of the tissue expander. A preoperative computed tomography (CT) scan showed CWD on the expander-inserted side; the antero-posterior (AP) length of the right chest wall was 127.2 mm and that of the left side was 150.2 mm. During the surgical procedure, a capsulectomy was performed, followed by the reconstruction of the right breast using a free transverse rectus abdominis myocutaneous flap. The patient exhibited symptom improvement immediately after the surgery and a 12-month follow-up CT scan revealed recoiling of the chest wall (right side, 147.4 mm; left side, 153.7 mm).ConclusionsThis case highlights the potential for CWD and recoil following tissue expander use in breast reconstruction. It is essential for surgeons to be aware of this phenomenon and to provide thorough explanations to patients who have undergone expander insertion, particularly those who have received radiation therapy.
| S-EPMC10570974 | biostudies-literature
Project description:Premature fusion of craniofacial joints, i.e. sutures, is a major clinical condition. This condition affects children and often requires numerous invasive surgeries to correct. Minimally invasive external loading of the skull has shown some success in achieving therapeutic effects in a mouse model of this condition, promising a new non-invasive treatment approach. However, our fundamental understanding of the level of deformation that such loading has induced across the sutures, leading to the effects observed is severely limited, yet crucial for its scalability. We carried out a series of multiscale characterisations of the loading effects on normal and craniosynostotic mice, in a series of in vivo and ex vivo studies. This involved developing a custom loading setup as well as software for its control and a novel in situ CT strain estimation approach following the principles of digital volume correlation. Our findings highlight that this treatment may disrupt bone formation across the sutures through plastic deformation of the treated suture. The level of permanent deformations observed across the coronal suture after loading corresponded well with the apparent strain that was estimated. This work provides invaluable insight into the level of mechanical forces that may prevent early fusion of cranial joints during the minimally invasive treatment cycle and will help the clinical translation of the treatment approach to humans.
| S-EPMC10963580 | biostudies-literature
Project description:Initial events of helix breakage as a function of load are considered using molecular dynamics simulations and milestoning analysis. A helix length of ?100 amino acids is considered as a model for typical helices found in molecular machines and as a model that minimizes end effects for early events of unfolding. Transitions of individual amino acids (averaged over the helix's interior residues) are examined and its surrounding hydrogen bonds are considered. Dense kinetic networks are constructed that, with milestoning analysis, provide the overall kinetics of early breakage events. Network analysis and selection of MaxFlux pathways illustrate that load impacts unfolding mechanisms in addition to time scales. At relatively high (100 pN) load levels, the principal intermediate is the 3(10)-helix, while at relatively low (10 pN) levels the ?-helix is significantly populated, albeit not as an unfolding intermediate. Coarse variables are examined at different levels of resolution; the rate of unfolding illustrates remarkable stability under changes in the coarsening. Consistent prediction of about ?5 ns for the time of a single amino-acid unfolding event are obtained. Hydrogen bonds are much faster coarse variables (by about 2 orders of magnitude) compared to backbone torsional transition, which gates unfolding and thereby provides the appropriate coarse variable for the initiation of unfolding. Results provide an atomic description of "catch-bond" behavior, based on alternative pathways, in which unfolding of a simple protein structural element occurs over longer timescales for intermediate (10 pN) loads than for zero (0 pN) or large (100 pN) loads.
| S-EPMC3406243 | biostudies-literature
Project description:BackgroundImplant-based breast reconstruction is the most common method of breast reconstruction in the United States, but the outcomes of subsequent implant-based reconstruction after a tissue expander complication are rarely studied. The purpose of this study was to determine the long-term incidence of implant loss in patents with a previous tissue expander complication.MethodsThis is a retrospective review of the long-term outcomes of all patients with tissue expander complications at a large academic medical center from 2003 to 2013. Patients with subsequent tissue expander or implant complications were compared to those with no further complications to assess risk factors for additional complications or reconstructive failure.ResultsOne hundred sixty-two women were included in this study. The mean follow-up period was 8.3 ± 3.1 years. Forty-eight women (30 percent) went on to undergo a second tissue expander or implant placement. They did not differ from women who went on to autologous reconstruction or no further reconstruction. Of these, 34 women (71 percent) had no further complications and 38 women (79 percent) had a successful implant-based reconstruction at final follow-up. There were no patient or surgical factors significantly associated with a second complication or implant loss.ConclusionsFollowing tissue expander complications, it is reasonable to offer women a second attempt at tissue expansion and implant placement. This study demonstrates that long-term success rates are high, and there are no definitive patient or surgical factors that preclude a second attempt at implant-based breast reconstruction.Clinical question/level of evidenceRisk, III.
| S-EPMC6310090 | biostudies-literature
Project description:Mammalian cells have evolved complex mechanical connections to their microenvironment, including focal adhesion clusters that physically connect the cytoskeleton and the extracellular matrix. This mechanical link is also part of the cellular machinery to transduce, sense and respond to external forces. Although methods to measure cell attachment and cellular traction forces are well established, these are not capable of quantifying force transmission through the cell body to adhesion sites. We here present a novel approach to quantify intracellular force transmission by combining microneedle shearing at the apical cell surface with traction force microscopy at the basal cell surface. The change of traction forces exerted by fibroblasts to underlying polyacrylamide substrates as a response to a known shear force exerted with a calibrated microneedle reveals that cells redistribute forces dynamically under external shearing and during sequential rupture of their adhesion sites. Our quantitative results demonstrate a transition from dipolar to monopolar traction patterns, an inhomogeneous distribution of the external shear force to the adhesion sites as well as dynamical changes in force loading prior to and after the rupture of single adhesion sites. Our strategy of combining traction force microscopy with external force application opens new perspectives for future studies of force transmission and mechanotransduction in cells.
| S-EPMC8964583 | biostudies-literature
Project description:The generation of breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) is closely associated with textured implants. The phenotype of BIA-ALCL cells is well examined, but its cell of origin remains unknown. Here we investigate what types of T cells are recruited and differentiated in the surrounding capsules and tissues as a consequence of continuous contact with a textured surface.MethodsCapsule and pericapsule tissues were recovered from patients who had textured or smooth tissue expanders (TEs). These samples were enzymatically digested, and T cells in the samples were analyzed using flow cytometry. Peripheral blood mononuclear cells from the same donors were utilized as a control.ResultsEffector memory CD4+ T cells predominantly infiltrated capsules and tissues without apparent differences between textured and smooth TEs. In these effector memory CD4+ T cells, CD4+ resident memory T cells were generated by smooth TEs but not by textured TEs. However, TNFRSF8/CD30 mRNA expression is higher in the CD69- effector memory CD4+ T cells than in the CD69+ ones.ConclusionTextured and smooth TEs differentially recruit and/or differentiate T cells in situ.
| S-EPMC8942776 | biostudies-literature
Project description:Subpectoral tissue expander breast reconstruction is often associated with muscle spasms, pain, and discomfort during tissue expansion. In this study, we hypothesized that an intraoperative injection of botulinum toxin A (BTX-A) in the pectoralis major muscle reduces the pain associated with tissue expansion and improves women's physical well-being.MethodsBetween May 2012 and May 2017, women undergoing immediate subpectoral tissue expander breast reconstruction were randomized to administer 100 units of BTX-A or a placebo injection. A numeric pain intensity scale and the physical well-being scale of the BREAST-Q: Reconstruction Module were used to test our hypothesis. Data on postoperative oral narcotic consumption were not collected.ResultsOf the 131 women included in the analysis, 48% were randomized to placebo and 52% to BTX-A. The preoperative median pain intensity score was 0 [interquartile range (IQR), 0-1], and the median preoperative BREAST-Q score was 91 (IQR, 81-100). The median slopes for the change in pain intensity scores from baseline throughout tissue expansion for those randomized to placebo and BTX-A were -0.01 (IQR, -0.02 to 0.00) and -0.01 (IQR, -0.02 to 0.00), respectively (P = 0.55). The median slopes for the change in BREAST-Q scores from baseline throughout tissue expansion for those randomized to placebo and BTX-A were 0.04 (IQR, -0.17 to 0.14) and 0.02 (IQR, -0.06 to 0.13), respectively (P = 0.89).ConclusionIn this study, we found that an intraoperative intramuscular injection of 100 units of BTX-A in the pectoralis major muscle did not reduce postoperative pain and patient-reported physical well-being when compared with placebo.
| S-EPMC7489665 | biostudies-literature
Project description:BackgroundDirect-to-implant (DTI) breast reconstruction after mastectomy has gained increasing popularity. While concerns over ischemic complications related to tension on the mastectomy flap persist, newer techniques and technologies have enhanced safety of this technique.ObjectivesTo compare clinical and patient-reported outcomes of DTI and 2-stage tissue expander (TE) reconstruction.MethodsA prospective cohort design was utilized to compare the incidence of reconstructive failure among patients undergoing DTI and TE reconstruction by unadjusted bivariate and adjusted multivariable logistic regression analyses. Secondary clinical outcomes of interest included specific complications requiring intervention (infection, seroma, hematoma, mastectomy flap necrosis, incisional dehiscence, device exposure) and time to final drain removal. Patient-reported outcomes on BREAST-Q were also compared.ResultsA total of 134 patients (257 breasts) underwent DTI reconstruction and 222 patients (405 breasts) received TEs. DTI patients were significantly younger with lower BMIs; less diabetes, hypertension, and smoking; and smaller breast sizes; they also underwent more nipple-sparing mastectomies with prepectoral reconstructions. Rates of any complication (18% DTI vs 24% TE, P = .047), reconstructive failure (5.1% vs 12%, P = .004), and seroma (3.9% vs 11%, P < .001) were significantly lower in the DTI cohort on unadjusted analyses; however, there were no significant differences on adjusted regressions. Patient-reported satisfaction with breasts, psychosocial well-being, and sexual well-being were more substantively improved with DTI reconstruction.ConclusionsPrepectoral DTI reconstruction is a viable option for postmastectomy reconstruction in carefully selected patients, with no significant increase in reconstructive failure or other complications.Level of evidence: 2
| S-EPMC11492281 | biostudies-literature