A Comparative Assessment of Outcomes Following Mandibular Distraction Osteogenesis and Tongue-Lip Adhesion in Pierre Robin Sequence.

The purpose of this study was to assess long-term outcomes of tongue-lip adhesion (TLA) and mandibular distraction osteogenesis (MDO) to resolve upper airway obstruction in patients with Robin sequence (RS). A retrospective cohort study was performed of subjects presenting to a tertiary care pediatric center who underwent either primary MDO or TLA for the treatment of RS between 2004 and 2020. N=59 subjects met inclusion criteria (n=34 MDO, n=25 TLA), and there were no significant differences in preoperative patient characteristics other than age at surgery (MDO 31 d vs. TLA 17 d, P=0.049). Preoperative apnea-hypopnea index (AHI) was similar between cohorts (33.9 and 46.7, P=0.38). Subjects who underwent MDO demonstrated improved AHI on initial postoperative polysomnogram performed at 2 weeks (3.4 vs. 11.6, P=0.014), however AHI at the second postoperative timepoint (270 vs. 142 d, P=0.007) was no different between cohorts (2.8 vs. 2.6, P=0.89). No subject in either group required enteral nutrition or supplemental oxygen at last follow-up. In subjects undergoing MDO, 14.7% demonstrated temporary asymmetric marginal mandibular nerve dysfunction. Forty-seven percent of MDO patients had injury to first primary molars. MDO and TLA both ultimately achieved similar long-term resolution of upper airway obstruction and associated feeding difficulties in patients with Robin sequence. MDO offered a more immediate airway improvement, but the procedure carried a potential risk of neurosensory and dental injury when compared with TLA.

In Situ Expansion, Differentiation, and Electromechanical Coupling of Human Cardiac Muscle in a 3D Bioprinted, Chambered Organoid.

RATIONALE: One goal of cardiac tissue engineering is the generation of a living, human pump in vitro that could replace animal models and eventually serve as an in vivo therapeutic. Models that replicate the geometrically complex structure of the heart, harboring chambers and large vessels with soft biomaterials, can be achieved using 3-dimensional bioprinting. Yet, inclusion of contiguous, living muscle to support pump function has not been achieved. This is largely due to the challenge of attaining high densities of cardiomyocytes-a notoriously nonproliferative cell type. An alternative strategy is to print with human induced pluripotent stem cells, which can proliferate to high densities and fill tissue spaces, and subsequently differentiate them into cardiomyocytes in situ. OBJECTIVE: To develop a bioink capable of promoting human induced pluripotent stem cell proliferation and cardiomyocyte differentiation to 3-dimensionally print electromechanically functional, chambered organoids composed of contiguous cardiac muscle. METHODS AND RESULTS: We optimized a photo-crosslinkable formulation of native ECM (extracellular matrix) proteins and used this bioink to 3-dimensionally print human induced pluripotent stem cell-laden structures with 2 chambers and a vessel inlet and outlet. After human induced pluripotent stem cells proliferated to a sufficient density, we differentiated the cells within the structure and demonstrated function of the resultant human chambered muscle pump. Human chambered muscle pumps demonstrated macroscale beating and continuous action potential propagation with responsiveness to drugs and pacing. The connected chambers allowed for perfusion and enabled replication of pressure/volume relationships fundamental to the study of heart function and remodeling with health and disease. CONCLUSIONS: This advance represents a critical step toward generating macroscale tissues, akin to aggregate-based organoids, but with the critical advantage of harboring geometric structures essential to the pump function of cardiac muscle. Looking forward, human chambered organoids of this type might also serve as a test bed for cardiac medical devices and eventually lead to therapeutic tissue grafting.

A Rare Case of a Giant Intramuscular Lipoma of the Upper Extremity in a Pediatric Patient.

Although lipomas are the most common benign soft tissue tumors, the non-infiltrating intramuscular subtype is relatively uncommon. As these masses typically present between the ages of 40 and 70, few cases have been reported in the pediatric population. We present a case of a giant intramuscular lipoma of the biceps brachii in an adolescent. He presented with a slow-growing, tender mass and had no neurovascular compromise of the limb. MRI was utilized to visualize the mass, and a muscle-sparing excisional biopsy was performed. Histologic evaluation confirmed a diagnosis of a benign lipoma. The patient went on to heal without a functional deficit. Large, growing soft tissue masses warrant work-up to rule out malignancy. Advanced imaging and excisional biopsy are necessary to confirm the diagnosis of a benign giant intramuscular lipoma, which is especially rare within the pediatric population. We discuss the prevalence and treatment of intramuscular lipomas, including a literature review of reports in the pediatric population.