A growth-accommodating implant for paediatric applications

Abstract

Medical implants of fixed size cannot accommodate normal tissue growth in children, and often require eventual replacement or in some cases removal, leading to repeated interventions, increased complication rates and worse outcomes. Implants that can correct anatomic deformities and accommodate tissue growth remain an unmet need. Here, we report the design and use of a growth-accommodating device for paediatric applications that consists of a biodegradable core and a tubular braided sleeve, with inversely related sleeve length and diameter. The biodegradable core constrains the diameter of the sleeve, and gradual core degradation following implantation enables sleeve and overall device elongation in order to accommodate tissue growth. By using mathematical modeling and ex vivo experiments using harvested swine hearts, we demonstrate the predictability and tunability of the behavior of the device for disease- and patient-specific needs. We also used the rat tibia and the piglet heart valve as two models of tissue growth to demonstrate that polymer degradation enables device expansion and growth accommodation in vivo.

Engineering precision biomaterials for personalized medicine

“…Although several regulatory hurdles limit widespread translation of customized devices for individual patients, precision biomaterials have the potential to address the most pressing limitations of using personalized medicine strategies in the clinic. Investing resources in the development of precision biomaterials may also usher in an era of living materials that integrate with a patient’s body and alter their properties at multiple length and time scales to meet the demands of maintaining health as the patient ages (35). Together, the implementation of unit operations to design precision biomaterials will continue to inspire new applications, address translational barriers, and provide innovative solutions in precision medicine.…”

Polyglycerol Hyperbranched Polyesters: Synthesis, Properties and Pharmaceutical and Biomedical Applications

“…However, most implants have a fixed size, limiting their efficacy and often requiring multiple interventions. Feins et al designed a device able to accommodate tissue growth, a critical characteristic for implants aimed at pediatric applications ( Figure 10) [157]. The device was composed of a PGSeb biodegradable core and an outer braided sleeve and as the PGSeb degraded by surface erosion, the diameter of the inner core progressively decreased, resulting in an extension of the braided sleeve ( Figure 10).…”

“…(a) Schematic of a degradable polymer core (dark blue) placed inside a braided sleeve to control sleeve diameter, coupling inner polymer degradation to braided sleeve elongation. (b) Braided sleeve behavior and core degradation[157]. Reprinted with permission from Springer Nature, copyright 2017.…”

Regenerative Therapy for Patients with Congenital Heart Disease

“…Recently, a very promising result was reported by a Harvard group that developed a new growth-accommodating device for pediatric application. 61 This device consists of two components: a degrading, biopolymer core and a braided, tubular sleeve that elongates over time in response to the tensile forces exerted by the surrounding growing tissue. As the inner biopolymer degrades, the tubular sleeve becomes thinner and elongates in response to native tissue growth.…”