Uniquely among mammalian organs, skin is capable of marked size change in adults, yet the mechanisms underlying this notable capacity are unclear. Here, we use a system of controlled tissue expansion in mice to uncover cellular and molecular determinants of skin growth. Through machine learning–guided three-dimensional tissue reconstruction, we capture morphometric changes in growing skin. We find that most growth is driven by the proliferation of the epidermis in response to mechanical tension, with more limited changes in dermal and subdermal compartments. Epidermal growth is achieved through preferential activation and differentiation of Lgr6 + stem cells of the epidermis, driven in part by the Hippo pathway. By single-cell RNA sequencing, we uncover further changes in mechanosensitive and metabolic pathways underlying growth control in the skin. These studies point to therapeutic strategies to enhance skin growth and establish a platform for understanding organ size dynamics in adult mammals.

Background: Various surgical techniques can be used to repair acute distal biceps tendon (DBT) tears; however, it is unknown which type of repair or implant has the greatest biomechanical strength and presents the lowest risk of type 2 failure. Purpose: To identify associations between the type of implant or construct used and the biomechanical performance of DBT repairs in a review of human cadaveric studies. Study Design: Systematic review and meta-regression. Methods: We systematically searched the EMBASE and Medline (PubMed) databases for biomechanical studies that evaluated DBT repair performance in cadaveric specimens. Two independent reviewers extracted data from 14 studies that met our inclusion criteria. The pooled data set was subjected to meta-regression with adjusted failure load (AFL) as the primary outcome variable. Procedural parameters, such as number of sutures, cortices, locking stitches, and whipstitches, served as covariates. Adjusted analysis was performed to determine the differences among implant types. The alpha level was set at .05. Results: When using no implant (bone tunnels) as the referent, no fixation type or procedural parameter was significantly better at predicting AFL. Cortical button fixation had the highest AFL (370 N; 95% CI, −2 to 221). In an implant-to-implant comparison, suture anchor alone was significantly weaker than cortical button (154 N; 95% CI, 30 to 279). Constructs using a cortical button and interference screw were not stronger (as measured by AFL) than those using a cortical button alone. The presence of a locking stitch added 113 N (95% CI, 29 to 196) to the AFL. The use of cortical button instead of interference screws or bone tunnels was associated with lower odds of type 2 failure. Avoiding locking stitches and using more sutures in the construct were also associated with lower odds of type 2 failure. Conclusion: Cortical button fixation is associated with greater construct strength than is suture anchor repair and a lower risk of type 2 failure compared with interference screw fixation or fixation without implants. The addition of an interference screw to cortical button fixation was not associated with increased strength. The presence of a locking stitch added 113 N to the failure load but also increased the odds of type 2 failure.

Background In 2014, the Plastic Surgery Residency Review Committee of the Accreditation Council for Graduate Medical Education (ACGME) increased minimum aesthetic surgery requirements. Consequently, the resident aesthetic clinic (RAC) has become an ever more important modality for training plastic surgery residents. Objectives To analyze demographics and long-term surgical outcomes of aesthetic procedures performed at the Johns Hopkins and University of Maryland (JHUM) RAC. A secondary objective was to evaluate the JHUM RAC outcomes against those of peer RACs as well as board-certified plastic surgeons. Methods We performed a retrospective chart review of all patients who underwent aesthetic procedures at the JHUM RAC between 2011 to 2020. Clinical characteristics, minor complication rates, major complication rates, and revision rates from the JHUM RAC were compared against two peer RACs. We compared the incidence of major complications between the JHUM RAC and a cohort of patients from the CosmetAssure (Birmingham, AL) database. Pearson’s chi-square test was used to compare complication rates between patient populations, with a significance set at 0.05. Results Four hundred ninety-five procedures were performed on 285 patients. The major complications rate was 1.0% (n = 5). Peer RACs had total major complication rates of 0.2% and 1.7% (P = 0.07 and P = 0.47, respectively). CosmetAssure patients matched to JHUM RAC patients were found to have comparable total major complications rates of 1.8% vs 0.6% (P = 0.06), respectively. At JHUM, the minor complication rate was 13.9% while revision rate was 5.9%. Conclusions The JHUM RAC provides residents the education and training necessary to produce surgical outcomes comparable to peer RACs as well as board certified plastic surgeons.

select group, improvement in diplopia occurred in 85.7% of cases with globe malposition and in 90.1% of cases with restrictive strabismus. One patient underwent additional strabismus surgery subsequent to orbital repair. CONCLUSION:Post-traumatic diplopia in patients with prior orbital reconstruction can be successfully managed in appropriate patients with a high degree of success. Indications for surgical management include (1) globe malposition and (2) restrictive strabismus. High resolution computer tomography and Lancaster red-green testing discriminate these from other causes that are unlikely to benefit from orbital surgery. Patients selected for surgery by this algorithm have markedly better diplopia outcomes than have previously been reported in the literature.