General Session: Value and Outcomes in Spine Surgery - Hall F

Presented by: A. Kasis

Author(s):

A. Kasis(1), D. Rahul(2), C. Jensen(1)

(1) Northumbria NHS Trust, Orthopaedic Spine Surgery, Ashington, United Kingdom
(2) Northumbria NHS Trust, Radiology Department, Ashington, United Kingdom

Abstract

Introduction: Bone Morphogenic Protein-2 (BMP-2) has been commonly used to increase the rate of spinal fusion. Prior to 2016, the authors used BMP-2 in combination with fresh frozen femoral head (FFFH) in Anterior Lumbar Interbody Fusion (ALIF) procedures with excellent results. Due to the significant shortage of BMP-2 in Europe at the beginning of 2016, a new technique was developed to replace the BMP-2 with a core of iliac crest bone autograft in combination with FFFH. The original BMP-2/femoral head technique of inserting BMP-2 inside the FFFH was adopted from the Gold Coast Spine, Australia. In this study we compare the fusion rate between the two techniques using CT scanning.

Methods: One hundred consecutive patients (50 in each group) who underwent ALIF procedures between 2013-2017 at L4-S1 for degenerative pathologies were reviewed. The osteoinductive +/- osteogenic bone graft (BMP-2 or iliac crest cancellous bone) was inserted in the middle of cancellous FFFH allograft into two drilled tunnels in the middle of the FFFH. When BMP-2 was used, a 2 mg piece was inserted into each drilled tunnel (4mg per level). When an autograft was used, two cores of cancellous iliac crest bone graft were obtained through a stab incision using a cannulated vertebral biopsy 10 gauge needle (Stryker®). All patients had a routine CT scan performed at 4-5 months after surgery to check for fusion. CT scan imaging was reviewed by a consultant radiologist who was blinded to the type of bone graft used.

Results: The were 50 consecutive patients in each group. There was no statistical difference in the age of the patients, the male/female ratio, the level of surgery or the indications for surgery. For the BMP-2 group, 8 were ex-smokers and the remainder had never smoked. The was radiological fusion in 49 patients (total of 53 levels) (98%). There was one non-union in this group in a non-smoker who had surgery for neuroforaminal stenosis. In the iliac crest group, there were 9 ex-smokers and the remainder had never smoked. There was also radiological fusion in 49 patients (total of 52 levels) (98%), and again non-union in one patient (DDD) who had never smoked. There were no complications from the donor bone graft site (pain, or infection or fracture) as one might have seen if the whole graft had been taken from the iliac crest, as opposed to using FFFH.

Conclusion: There has been a huge amount of debate in the literature during the past decade regarding the potential risks associated with BMP-2 use, and so the use of bone core autografts in this way, removed these risks. The osteogenic properties of the Iliac crest bone core, in addition to its osteoinductive profile may give it a further advantage over BMP-2 (only osteoinductive) in achieving a solid fusion mass. The cost of using a core autograft was significantly less than using BMP-2. We used iliac crest bone core autografts as an alternative to BMP-2 in ALIF procedures using this well established technique, and found comparable fusion rates in the two groups.