An in vivo study to investigate an original intramedullary bone graft harvesting technology

Abstract

Background Harvesting bone graft (BG) from the intramedullary canal to treat bone defects is largely conducted using the Reamer–Irrigator–Aspirator (RIA) system. The RIA system uses irrigation fluid during harvesting, which may result in washout of osteoinductive factors. Here, we propose a new harvesting technology dedicated to improving BG collection without the potential washout effect of osteoinductive factors associated with irrigation fluid. This novel technology involves the conceptual approach of first aspirating the bone marrow (BM) with a novel aspirator prototype, followed by reaming with standard reamers and collecting the bone chips with the aspirator (reaming–aspiration method, R–A method). The aim of this study was to assess the harvesting efficacy and osteoinductive profile of the BG harvested with RIA 2 system (RIA 2 group) compared to the novel harvesting concept (aspirator + R–A method, ARA group). Methods Pre-planning computed tomography (CT) imaging was conducted on 16 sheep to determine the femoral isthmus canal diameter. In this non-recovery study, sheep were divided into two groups: RIA 2 group (n = 8) and ARA group (n = 8). We measured BG weight collected from left femur and determined femoral cortical bone volume reduction in postoperative CT imaging. Growth factor and inflammatory cytokine amounts of the BGs were quantified using enzyme-linked immunosorbent assay (ELISA) methods. Results The use of the stand-alone novel aspirator in BM collection, and in harvesting BG when the aspirator is used in conjunction with sequential reaming (R–A method) was proven feasible. ELISA results showed that the collected BG contained relevant amounts of growth factors and inflammatory cytokines in both the RIA 2 and the ARA group. Conclusions Here, we present the first results of an innovative concept for harvesting intramedullary BG. It is a prototype of a novel aspirator technology that enables the stepwise harvesting of first BM and subsequent bone chips from the intramedullary canal of long bones. Both the BG collected with the RIA 2 system and the aspirator prototype had the capacity to preserve the BG’s osteoinductive microenvironment. Future in vivo studies are required to confirm the bone regenerative capacity of BG harvested with the innovative harvesting technology.

In vivo study to assess fat embolism resulting from the Reamer-Irrigator-Aspirator 2 system compared to a novel aspirator-based concept for intramedullary bone graft harvesting

“…Using the open-source medical image viewer Horos (version 3.3.6), the smallest diameter (isthmus) was determined by first measuring the length of the femur as defined from the trochanteric fossa to the condyles. The IM canal diameter at the isthmus was determined at the midway point of the total femur length as described previously in detail [ 3 ].…”

“…All surgical procedures were performed by the same surgeon (M.L.) as described previously [ 3 ]. Briefly, an incision was made 1–2 cm proximal to the greater trochanter, dissection was performed to expose the trochanteric fossa, which was opened under radiographic guidance with a cannulated Ø 10 mm rigid reamer (Stryker Trauma GmbH, Schoenkirchen, Germany) inserted over a K-wire for access to the femoral medullary canal.…”

“…In a first step, using the recently introduced [ 3 ] aspirator prototype (A, BM evacuation), BM was aspirated from the medullary cavity. Subsequently, during the second step, reaming was performed using a guide-wire and the Bixcut reamer (modular reamer head kit, Stryker Trauma GmbH, Schoenkirchen, Germany) in sequential steps with increments described above for the RIA 2 group.…”

“…To achieve effective BG harvesting, the RIA system applies continuous irrigation and suction during IM reaming of long bones. Recently, a novel harvesting concept aimed at improving the BG collection without the potential washout effect of osteogenic factors in the graft material associated with the RIA system’s irrigation fluid was successfully tested [ 3 , 4 ]. This novel concept includes the option of initially aspirating the bone marrow (BM) using a novel aspirator prototype (aspirator, A), followed by sequential reaming using standard reamers and collecting BG with the novel aspirator prototype (reamer + aspirator, R + A), which has been shown to have the capacity to preserve the BG’s osteoimmune microenvironment associated with high osteogenic potential (A + R + A concept) [ 3 ].…”

“…Notably, in a sheep model, effective emptying of the femoral IM canal of the BM using multiple suction ports before reaming of nonfractured bone with conventional reamers was associated with reduced IM pressure and lung embolism [23; 24]. In line with this conceptual approach, the new harvesting concept with a dedicated aspirator allows BM to be evacuated from the IM canal prior to BG harvesting, the overall concept being defined as A + R + A with the use of the aspirator (A, BM evacuation) and reamer + aspirator (R + A, harvesting morselized endosteal bone) [ 3 ]. Yet it is crucial to assess its FE capacity to ensure that there are no increased adverse events using this technique.…”