507 - Perioperative Complications in Lumbar Spinal Fusions Using Low-Dose rh...

#507 Perioperative Complications in Lumbar Spinal Fusions Using Low-Dose rhBMP2

Lumbar Therapies and Outcomes

Poster Presented by: Z. Liau

Author(s):

Z.Q.G. Liau (1)
J.N. Ruiz (1)
H.K. Wong (1)

(1) National University Health System, University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, Singapore, Singapore

Abstract

Purpose of the Study: There are many reports on the use of recombinant bone morphogenetic-2 (rhBMP2) to augment lumbar spinal fusion surgery for varying spinal conditions. Use of rhBMP2 is known to have associations with multiple complications, especially in higher doses. However, there is no consensus on the appropriate rhBMP2 dose. We present our institutional experience on the use of low-dose rhBMP2 in a series of patients who underwent lumbar fusion, and compare them to a similar cohort of patients who also underwent lumbar spinal fusion without rhBMP2, focusing on perioperative complications.

Methods used: We retrospectively reviewed a consecutive series of 141 patients who underwent one-level (94 patients), two-level (36 patients) and three-level (11 patients) transforaminal lumbar interbody fusion (TLIF) for degenerative conditions in our institution from 2008-2011, with a minimum of 1 year follow up. Ninety-seven patients underwent TLIF without rhBMP2 (BG group; mean age 61, range 17-83), and 44 patients underwent TLIF with rhBMP2 (BMP group; mean age 62, range 19-84). Local bone graft was used in the BG group. The BMP group received local bone graft and rhBMP2 positioned at the sentinel graft site and inside a PEEK cage with a mean dose of 2.12mg per level. Postoperative case notes and subsequent clinic notes were assessed to determine type of complications.

Summary of Findings: Sixteen complications were noted in 10 patients for BG group, whereas 10 complications were noted in 10 patients for the BMP group. Sub-analysis of the different complication categories showed a trend towards higher complication rates in the BMP group vs BG group for infection (5% vs 3%, respectively), excessive wound drainage (5% vs 3%, respectively), as well as the development of new neurologic symptoms (4% vs 2%, respectively). However, these did not reach statistical significance (p>0.05). Four patients with postoperative wound infections (1 in BMP group; 3 in BG group) required another operation to address the infective focus. All 6 new neurologic symptoms in the BMP group resolved by 1-year, whereas 1 of the 12 new neurologic symptoms in the BG group persisted until last follow up of 1-year.

Conclusions: Our preliminary results show a trend towards higher complication rates for wound infection, high wound drainage, and the development of new neurologic symptoms after TLIF with rhBMP2, including 1 deep infection requiring formal surgical debridement. However, these rates were assessed to be comparable and not inferior to standard TLIF in our series of patients. Assessment of fusion rate and clinical outcome will determine the utility of using a low-dose rhBMP2 regimen in our institution.