THE USE OF INTERFUSE S™, AN INNOVATIVE MODULAR INTERVERTEBRAL BODY FUSION DEVICE AS A LESS INVASIVE ALTERNATIVE TO THE CONVENTIONAL BILATERAL LUMBAR FUSION SYSTEMS

TIMOTHY M. MURPHY M.R.C.S.I., NEIL MARSHALL WRIGHT M.D.

DEPARTMENT  OF  NEUROLOGICAL  SURGERY-WASHINGTON  UNIVERSITY ST.   LOUIS

INTRODUCTION

The lnterfuse® lntervertebral Body Fusion is a modular system consisting of an integral rail and slot multi-seg­ mental system, designed for use with autogenous bone graft, and with supplemental spinal fixation systems. This system allows the surgeon to customize the width of the device through a less invasive unilateral posterior lumbar interbody fusion, as opposed to conventional systems which typically come prepared in preset sizes.

MATERIALS AND METHODS

We use the lnterfuse® system in patients with degenerative disc disease and/or spondylolisthesis undergoing intervertebral lumbar spinal fusion. 23 consecutive patients undergoing interbody fusion were prospectively assessed, with pre-operative, intra-operative and post-operative variables being recorded. The most recent   11 patients had the lnterfuse system implanted, whereas the previous 12 patients, with the same symptoms, underwent implantation of the conventional system. Outcome measures assessed included: intra-operative blood loss, operating time, hospital stay, BMI, pre and post-operative pain scores, spondylolisthesis measurements both pre- and postoperatively, degrees of subsidence, and rates of fusion.

AP AND LATERAL VIEWS OF FIVE MODUALES   IN-SITU

(L) AP view of five modules in-situ using lnterFuse® device.

(R) Lateral view of same.

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OPERATIVE MOVIE

This short intraoperative movie highlights the benefits of using less invasive InterFuse® device systems for intervertebral lumbar fusion.

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Presented at the Congress of Neurological Surgeons 2009 Annual Meeting Digital Poster #4042

STANDARD VS. INTERFUSE COMPARISON

Hospital Stay (days) 4.9 4.5
Operative Time (minutes) 180 181
Blood Loss (mls) 433 354
Body Mass Index 28.4 32.4
Pre-operative Spondylolisthesis (mm) 5.49 8.17
Post-op Spondylolisthesis (mm) 3.2 3.5
Reduction in Spondylolisthesis (%) 41.7 48.8
Mean Pre-operative VAS 6.3 5
Mean Post-operative VAS (at 6 weeks) 2.3 1.1

RESULTS

Though the InterFuse® system was used on heavier patients, both the operative blood loss and the hospital stays were less. The InterFuse® system achieved a slightly better restoration in disc height, and a greater correction in spondylolisthesis, compared with those treated with a conventional fusion system. No increase in operating time was seen in the InterFuse® patient group, despite achieving a much larger interbody footprint, through a unilateral smaller dis space opening.

CONCLUSIONS 

The InterFuse® is a viable flexible alternative to conventional PLIF in patients presenting with degenerative disc disease or spondylisthesis, allowing a less invasive approach that does not compromise patient care or surgical efficiency, whilst also achieving placement of a significantly larger interbody footprint.

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