Closing-wedge Osteotomies: Can We Do and Teach Better?

BACKGROUND: Wedge osteotomies are ubiquitous in pediatric orthopaedics and limb deformity surgery; however, there is no universally preferred methodology for these procedures. This study aims to determine the relative accuracy and effectiveness of several measuring and marking methods to guide best practices for wedge-shaped osteotomies in long bones. METHODS: An observational cohort study was completed. Orthopaedic residents (postgraduate years 1 to 5) completed 30-degree wedge osteotomies on a sawbone (Pacific Research Lab) femur utilizing a standard oscillating saw under 3 measuring conditions: (1) no measurement tool, (2) 30-degree triangle, and (3) goniometer, in combination with 2 different marking methods: (1) marking pen or (2) pin placement. Demographic characteristics and osteotomy performance (quality, completion time, and accuracy) were assessed. Quality was ranked as perfect (1), mild step-off (2), or gross surface irregularity (3). Multivariate regressions and analysis of variance were performed comparing demographics, osteotomy performance, and measuring methods. RESULTS: Twenty-four residents were included for analysis; 6 were female (25%). Female sex was independently associated with longer completion time when evaluating all combined scenarios (138 vs. 99 s, P =0.003) without differences in surface quality or angle accuracy. There were no significant associations between measuring technique and accuracy or surface quality, but use of the goniometer and the triangle both were associated with significantly longer completion time compared with no visual aid ( P =0.002 and 0.007). When controlling for measuring technique, use of the pen as a marking technique had significantly shorter completion times ( P <0.001), higher surface quality ( P <0.001), and better accuracy ( P <0.001) than guide pins. CONCLUSIONS: We recommend the use of a marking pen in combination with the surgeon's preferred measuring guide to optimize trainees' performance of closing wedge osteotomies. Future research is necessary to corroborate these findings in a higher fidelity setting, such as a cadaveric study. Further, while male residents complete wedge osteotomies quicker than female residents, quality and accuracy are comparable among trainees. Slower pace should not be conflated with poor performance but rather should inform effective intraoperative teaching for diverse trainees.

High-resolution characterization of gene function using single-cell CRISPR tiling screen.

Identification of novel functional domains and characterization of detailed regulatory mechanisms in cancer-driving genes is critical for advanced cancer therapy. To date, CRISPR gene editing has primarily been applied to defining the role of individual genes. Recently, high-density mutagenesis via CRISPR tiling of gene-coding exons has been demonstrated to identify functional regions in genes. Furthermore, breakthroughs in combining CRISPR library screens with single-cell droplet RNA sequencing (sc-RNAseq) platforms have revealed the capacity to monitor gene expression changes upon genetic perturbations at single-cell resolution. Here, we present "sc-Tiling," which integrates a CRISPR gene-tiling screen with single-cell transcriptomic and protein structural analyses. Distinct from other reported single-cell CRISPR screens focused on observing gene function and gene-to-gene/enhancer-to-gene regulation, sc-Tiling enables the capacity to identify regulatory mechanisms within a gene-coding region that dictate gene activity and therapeutic response.