Factors influencing intraoperative conversion from double- to single-incision mastectomy with free nipple grafts in 352 transgender and non-binary patients.

BACKGROUND: Double-incision mastectomy (DIM) with free nipple grafts (FNG) is a common technique employed in gender-affirming mastectomy (GAM), but is associated with a high scar burden. Intraoperatively, the surgeon may opt for a single-incision mastectomy (SIM) along the inframammary folds (IMF) to optimize aesthetic outcomes. This study sought to identify factors predictive of intraoperative conversion. METHODS: From February 2018 to November 2022, TGNB patients who underwent GAM at a single institution were retrospectively reviewed. Data regarding patient characteristics, perioperative details, postoperative complications, and aesthetic satisfaction were collected. RESULTS: A total of 352 patients were identified. Median age and body mass index (BMI) were 25.0 years (IQR: 9.0) and 28.5 kg/m2 (IQR: 8.5), respectively. Most patients received IMF incisions (n = 331, 94.0%); of whom, 66 (19.9%) underwent intraoperative conversion from DIM to SIM with FNG. Larger breast cup-size (p < 0.001) and a greater degree of ptosis (p = 0.002) preoperatively were significantly associated with intraoperative conversion to SIM. There was no significant association between intraoperative conversion and the ratio of intermammary distance to the width of the chest wall (p = 0.086). Overall complication rates were significantly higher among patients with diabetes mellitus (p = 0.015) and a greater degree of ptosis (p = 0.018). 77.8% (n = 274) of patients were satisfied with their aesthetic outcome. NPWT usage was associated with higher rates of aesthetic satisfaction (83.6% vs. 77.8%; p = 0.005). CONCLUSION: Patients with larger breast cup size and greater degree of ptosis should be counseled preoperatively that they may be at a higher risk of conversion to a singular incision.

Ion-Transport Properties of Polydimethylsiloxane-Based Ionomers with Amidinium or Imidazolinium Alkyldithiocarbamate Pendant Groups in Low Dielectric Solvents or as Neat Liquids.

The ion transport properties of ionomers comprised of polydimethylsiloxanes with amidinium or imidazolinium attached side chains and alkyldithiocarbamate anions (where alkyl is hexyl or octadecyl) have been investigated in chloroform solutions principally and as neat liquids. The influence of modifying the molecular weights of the polydimethylsiloxanes, the frequency of their amidininium or imidazolinium side groups, and temperature on the conductivity have been explored. When a solvent more polar than chloroform, syn-tetrachloroethane, was employed, a large increase in the ionic conductivity was found despite there being an increase in the viscosity of the solution. At least in these two solvents, polarity is more important in determining the conductivity than the viscosity. When normalized for ion content, Walden plots of the ionomer solutions at different ionomer concentrations approached values found for 1 M aqueous KCl. As neat liquids, the amidinium and imidazolinium hexyldithiocarbamate ionomers exceeded the values associated with the "superionic" region of the Walden plot (i.e., above the conductivity values for 1 M aqueous KCl). As ion content and polymer molecular weight increased, larger decoupling between bulk viscosity and ionic conductivity was noted, probably as a result of changes in the dynamic fragility of the ionomers.

Effects of cyclic and acyclic amidine side-chains on the properties of polysiloxane ionomers constructed in situ from three uncharged components.

Ionomers, polysiloxanes with imidazolinium dithiocarbamate side chains, have been synthesized in situ from three uncharged components-a polysiloxane with imidazole side chains, CS2, and hexylamine or octadecylamine. Their structural and dynamic properties are compared over a temperature range of 0-50 °C with those of the analogous ionomers in which the polysiloxanes have amidinium side chains. The results, primarily from differential scanning calorimetry, powder X-ray diffraction measurements, and rheology show that the small structural (and smaller electronic) differences between the cyclic 5-membered ring imidazolinium and acyclic amidinium groups have marked effects on the bulk properties of the ionomers. These include their shear strengths and the manner in which the microcrystalline portions of the ionomers with dithiooctadecylcarbamate anions are packed. Thus, it is possible to finely tune the natures of the ionomers from one polysiloxane by changing temperature, the chain length of the alkylamine, and the nature of the base attached to the polysiloxane chain. Why these changes occur to the various properties is discussed.