General Session: Innovative Technologies I - Hall F

Presented by: P. Slosar

Author(s):

P. Slosar(1), J. Reynolds(1), S. Martineck(1), S. Slosar(2), N. Goldthwaite(1)

(1) SpineCare Medical Group, Daly City, CA, United States
(2) University of Wisconsin, Madison, WI, United States

Abstract

Background: Linking basic science data to clinical results can be difficult. Published studies demonstrate osteoinductive properties and low inflammation with micron-textured titanium surfaces, even without the addition of exogenous biologic additives. Interbody implants with these surface characteristics may be able to actively stimulate a portion of the fusion integration, potentially reducing surgeons' reliance on the more expensive and inflammatory biologic additives. BMP is associated with high fusion rates but authors have published on complications including high inflammation, osteolysis, and heterotopic bone formation. Some demineralized bone matrix products claim increased activity due to retained allograft growth factors (DBM+AGF). Ceramics are usually combined with bone marrow aspiration (Ceramic/ BMA). Finding the proper balance between the biological activities of the bone graft, the host, and the interbody implant would be relevant to clinical fusion outcomes.

Objectives: To determine if comparable clinical outcomes and cost savings opportunities can be realized in ALIF fusions with a micron-surface titanium implant, comparing 3 different bone graft substitutes of variable biological potencies.

Methods: 137 patients undergoing anterior lumbar interbody fusions were enrolled consecutively and followed for 24 months. All patients received implants with a unique micron-scale textured surface. Group 1: 75 patients received rhBMP-2. Group 2: 62 patients received a bone graft extender (DBM+AGF or ceramic). Clinical outcomes (VAS/ ODI) were collected for 2 years after surgery. Cost savings analysis was performed using manufacturer's list pricing.

Results: Both groups achieved similar and clinically significant improvements at all time points compared to pre-op baseline. (Table 1) Although not statically significant, there was a strong trend toward better improvements in VAS and ODI scores at all time points favoring the non-BMP patients (Group 2). Similar outcomes were observed between the DBM+AGF and ceramic groups. Leg pain was higher at all time points in the BMP cohort (Group 1), compared to the non-BMP cohort (Group 2) reaching statistical significance at 2 years. There were no fusion revisions or non-unions in either group at 24 months. List pricing for biologic graft materials used (per segments fused) are noted in Table 2. Cost savings between the high and low cost biologics was $2565 (1 level fusion), $2373 (2 level), and $2103 (3 level).

Conclusions: Biological activity of bone graft extenders may be less relevant in the presence of an osteoinductive fusion implant. There was no measurable clinical benefit realized by using BMP or DBM+GF with this specific ALIF implant. Results may vary however with other implants. The patients in the non-BMP group trended towards better clinical outcomes (VAS/ ODI) at all time points with statistically significant lower residual leg pain at 2 yrs., compared to the BMP group. These results may be related to a reduced inflammatory environment, allowing for a more physiological fusion process with the utilization of an osteoinductive implant surface. This study demonstrates that excellent clinical outcomes and significant cost savings can be achieved in these cases without the need for the most expensive or inflammatory biologics.