Lightning Podiums: Spinal Potpourri - 803B

Presented by: M. Rauschmann

Author(s):

M. Rauschmann(1), M. Reckert(1), B. Chatterjee(1)

(1) Orthopädische Universitätsklinik, Friedrichsheim gGmbH, Frankfurt am Main, Germany

Abstract

Background: The need for improved fusion technology led to the development of a lumbar interbody fusion implant with unique biomechanical characteristics that has the potential to enhance bone on-growth and through-growth. The proprietary implant using truss-based technology allows loading along the trusses throughout the fusion volume of the device which may promote stem cell differentiation into osteoblast and speed up the fusion process.

Purpose: It is hypothesized that fusions performed using the truss-based technology will result in higher fusion rates and reduced times for bone formation due to the biomechanical properties of the implant design when compared to annular implant designs. The purpose of this study was to evaluate the performance of the truss-based technology with two different graft materials, crushed cancellous allograft bone or autologous bone marrow aspirate.

Materials/Methods: Patients were randomized into one of two treatment groups (Group 1: crushed cancellous allograft bone versus Group 2: autologous bone marrow aspirate (BMA)) both receiving 1- or 2-level lumbar interbody fusion with supplemental fixation. It was determined that a total of 40 patients (20 patients per group) were needed to achieve a statistical significance level of 0.05. The 4WEB® Anterior Spine Truss System™ Interbody Fusion Device (ASTS; 4WEB Medical, Frisco, TX) was used in all cases. The clinical outcome measures included the Oswestry Disability Index (ODI), Visual / Analog Scales (VAS) separately assessing back and leg pain, EQ5-D, and adverse events. Clinical and radiographic data was obtained prior to hospital discharge and at 3, 6, and 12-months post-operatively. All radiographs were independently reviewed.

Results: Between January, 2015 and February, 2016, 42 consecutive patients were recruited, consented, and randomized into one of two previously defined study groups and underwent the index study procedure. There was one patient in Group 2 that withdrew from the study prior to surgery. In addition there were 2 patient deaths due to cardiac events (one in each group) determined to be unrelated to the surgical procedure. Between study groups, there was no statistical difference in average age (Group 1: 59.1yrs ±14.6, Group 2: 64.3yrs ±13.9, p = 0.12). However, there was a marked difference in patient gender distribution (Group 1: M = 19%; F = 81%, Group 2: M = 48%; F = 52%). Chronic smokers were similarly distributed across the study groups (Group 1: 67%, Group 2: 75%). All clinical variables significantly improved following surgery (p < 0.05). There was no statistical difference between groups at any follow-up for all clinical variables measured (p < 0.05). This was also observed for smokers versus non-smokers. All patients achieved radiographic evidence of Grade II fusion (probable fusion, graft intact, not fully remodeled, no areas of lucency) at 6-months post-operatively. There was no radiographic evidence of bone to implant radiolucencies, implant migration or implant subsidence at 3, 6 and 12-months post-operatively.

Conclusions: In conclusion, the clinical and radiographic results from this prospective, randomized study have shown that reliable fusion can be obtained utilizing the proprietary truss-based 4WEB® ASTS implant utilizing allograft bone or BMA only. As a result of these findings, there may be intra-operative biologic cost reduction implications across multiple patient populations.