147 - Clinical and Radiographic Outcomes after ALIF, TLIF, LLIF or PLIF with...

#147 Clinical and Radiographic Outcomes after ALIF, TLIF, LLIF or PLIF with Spinous Process Fusion in an Elderly Cohort

MIS Techniques and Outcomes

Poster Presented by: A. Vokshoor

Author(s):

A. Vokshoor (1)

(1) Institute of Neuroinnovation, Marina Del Rey, CA, United States

Abstract

Introduction: Spinous process fusion combined with interbody fusion is becoming a common technique to treat lumbar back pain, however little to no data or clinical outcomes have been reported to date. In this study we describe VAS and fusion outcomes in a cohort of elderly patients with lumbar back pain due to degenerative changes in the spine.

Methods: This was a retrospective cohort study. Charts from 39 consecutive patients from March of 2009-October of 2011 who had ALIF, LLIF, TLIF or PLIF plus interspinous fusion facilitated by a spinous process fusion device (Lanx, Broomfield Co) were reviewed. Six early patients also had unilateral pedicle screws. Demographic, diagnostic, complications, and operative data were recorded, as well as radiographic and clinical (VAS) outcomes. VAS improvement over time was assessed with a linear mixed model which included a random intercept to account for repeated measures. Posterior interspinous fusion and interbody fusion were assessed as follows: For interspinous fusion: Grade 1 = small islands of bone. Grade 2 = larger islands of coalescence with bridging to the surrounding anatomy. Grade 3 = technically fused: some solid incorporation and bridging bone. Grade 4 = solid fusion with incorporation and obvious stability and maturity. For interbody fusion the Brantigan, Steffee, Fraser (BSF) criteria were utilized.

Results: Mean age was 63 years (SD=11). There were 17 women in the cohort. 10 patients had prior lumbar surgery. Diagnosis was spondylolisthesis/stenosis. The mean preoperative VAS score was 6.7 (SD= 2.3). VAS score was reduced by a mean of 3.3 points (95% CI= -4.2 - -2.2, p=< 0.001)) at 3 months and this improvement was maintained out to 12 months (figure 1). Mean Estimated blood loss was 213.4 mls, (SD=210.2). Mean length of stay was 3.3 days (SD=1.7). 28 patients had high quality CT images available to assess fusion status. Fusion rate was 96% for interspinous fusion, and 85.2% for interbody fusion. There was no difference in fusion rates for the 6 patients with unilateral pedicle screws. Bone graft material was either autologous, Mastergraft, Vitoss, DBM or a combination. No BMP was used. There were no spinous process fractures, or instances of device dislodgement or breakage. Three patient shad an intraoperative complication; all were durotomies. There were 6 revisions due to: two were due to pseudoarthrosis, adjacent segment disease, infection, post operative trauma (patient fell down the stairs).

Conclusion: Lumbar interbody fusion with interspinous fusion and fixation results in clinically and statistically significant improvement in pain scores with reasonable fusion rates.