Bone marrow aspiration device to optimize mesenchymal stem cell yields
Student Team: Spinal Countdown
Aaron Metyko (LinkedIN) ; Andrea Guerrero Garcia ; Conor Wesolowski ; Corinna Shimalla ;
Trevor Turner MD, Georgia Bone and Joint
The wide cell-line differentiation abilities and healing properties of mesenchymal stem cells (MSCs) have prompted physicians to use them in regenerative stem cell therapy for wound and tissue repair. Of particular interest is their use in therapies for musculoskeletal injuries, which occur in more than 100 million Americans. Current bone marrow aspiration techniques along the posterior superior iliac crest harvest a suboptimal yield of mesenchymal stem cells, limiting the ability of orthopedic physicians to meet patient needs without performing additional harvests. The negative pressure produced by the aspiration process causes blood vessels in the bone marrow to burst, diluting the sample with peripheral blood. Our solution involves altering the current trocar design to have five smaller emitting needles entering the bone marrow cavity instead of one large needle. This increases the number of aspiration sites, which has been shown to increase the fraction of MSCs collected by reducing site cannibalization. SolidWorks Simulation software was utilized to inform the final prototype design. Emitting needle structure and material were assessed using Finite Element Analysis. The emitting needles were selected to have a bend of 35 degrees and are composed of a polyether-ether ketone (PEEK) for a balance of strength and flexibility. Computational fluid dynamics simulations were used to assess the pressure on the fluid being aspirated to ensure it was below critical thresholds that could lyse or damage the viability of the MSCs being harvested. This testing informed the selection of needle wall thickness and trocar gauge, as well as ensuring that desired pressure ranges and equal flow were maintained throughout the five emitting needles. The final design features include five emitting needles merged to an upper cannula that connect via Luer Lock to an aspirating syringe to allow for aspiration from multiple locations which reduces puncture sites and avoids cannibalization.