Sunday, April 28, 2024
4/28/2024
PROJECT SUMMARY/ABSTRACT Rotator cuff (RC) tears are common, affecting over 20% of the general population with prevalence increasing with age. A common treatment method is arthroscopic RC repair surgery, where one of many different fixation techniques are utilized to mechanically attach the torn rotator cuff tendon to the bone. However, there is still a high incidence of retear – ranging between 30% to 94% - leading to instability of the joint, pain, potential repeat repair surgery, and depending on severity of the tear, highly invasive total shoulder arthroplasty. Several causes of RC tear repair failure exist including stress risers in the tendon due to sutures, insufficient reattachment of and healing between the tendon and bone, mechanical instability, and poor quality of tissue. There is a need to innovate in this field in order to develop new ways to mitigate the risk of tendon tear after arthroscopic RC repair surgery. One potential solution is to design a system that targets improving upon the most common identified failure modes. 3D bioprinting has emerged as a novel technique for fabricating structures with precise geometry and user defined mechanical and biochemical properties. One limitation to the current class of handheld 3D bioprinters being used for biomedical applications is that in their current form, they require direct access to the tissue that is being treated, which necessitates a highly invasive, open procedure. Arthroscopic 3D bioprinting is a potential high impact medical treatment, where structures with user defined geometry, mechanical properties, and biologic components can be precisely applied to a damaged tissue in a minimally invasive manner. Using an arthroscopic 3D printing system, a tendon can be “spot-welded” back down to the bone to provide a continuous mechanical interface between the tendon and bone using a previously described Janus Tough Adhesive (JTA) biomaterial. The objective of this proposal is to develop an arthroscopic 3D bioprinter to precisely deposit bioinks to enhance the attachment of torn RC tendons to the bone. In Aim #1 we will construct an arthroscopic 3D bioprinter with the following key design features: 1) JTAs will be deposited via extrusion, 2) light will be focused at the tip of the nozzle to facilitate photopolymerization, 3) control of extrusion and polymerization on the device handle, 4) replaceable cartridges, 5) sterilizable, and 6) no more than 7mm in diameter (standard arthroscope geometry). We will evaluate the effect of printing parameters and JTA concentrations on 3D printed structures. We will also perform a proof of principle demonstration in a cadaver. In Aim #2 we will evaluate how and arthroscopic 3D bioprinted RC tear repair can enhance mechanical properties of the tendon-bone interface in a rabbit model. An arthroscopic 3D printer will be used to “spot weld” the tendon back to the bone after a traditional RC repair in a rabbit model to reduce the point loading of the tendon where the sutures are placed. Load to failure of the repaired RC will be evaluated and compared to the gold standard (suture repair). These are the foundational studies necessary to develop a new surgical tool to allow surgeons to incorporate minimally invasive 3D printing strategies for augmenting mechanical and biologic properties in RC tear repair.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).
