Studies find FlareHawk expandable cage safe and efficacious 


Integrity Implants, has today announced the publication of recent clinical articles in the International Journal of Spine Surgery (IJSS) which highlight the safety and efficacy of the FlareHawk expandable interbody cage. 

According to a press release from Integrity Implants, the studies have found that the novel biplanar expandable cage provides effective vertebral body slip or spondylolisthesis reduction and improvement in radiographic and clinical parameters with no reported subsidence, migration, or endplate violation

The most recently published study, published in IJSS October 2020, is entitled Clinical and Radiographic Outcomes After Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) – Early Experience Using a Biplanar Expandable Cage for Lumbar Spondylolisthesis. This study was a retrospective review of 13 patients treated during a one year period.

The study found a mean slippage reduction of 6.0mm along with an improvement in segmental lordosis, increase in foraminal and posterior disc height, and an additional improvement in all radiographic parameters postoperatively. 

Lee Tan, Assistant Professor of Neurological Surgery at UCSF Medical Center in San Francisco and lead author of this study, California, USA, commented, “My early experience shows good short-term radiographic and clinical outcomes, with almost complete reduction of spondylolisthesis postoperatively in all cases. The absence of nerve root injury is suggestive that the biplanar expandable cage is safe and obviates the need for excessive nerve root retraction during cage insertion,” he continues, “Remarkably, we had no cases of endplate violation or cage subsidence in this cohort. This is significantly lower than the rates reported in the current literature, which range from 6% up to 33%. I believe that the biplanar expansion is key to decreasing the likelihood of subsidence.”

As discussed in the article, one possible explanation for the clinical success is that the expansion of the cage in the horizontal plane increases surface area contact with the endplates to better distribute the load and reduce stress, while the multi-material cage design consisting of a titanium shim inserted into a PEEK shell allows the cage to contour to the patient’s endplates, further reducing the risk of endplate violation.

Another article was entitled, Bidirectional Expandable Technology for Transforaminal or Posterior Lumbar Interbody Fusion: A Retrospective Analysis of Safety and Performance, lead authored by Domagoj Coric, Chief of Neurosurgery at Carolinas Medical Center and Spine Division Chief at Atrium Musculoskeletal Institute in Charlotte, North Carolina, USA. 

The study followed strict inclusion criteria including the allowance of only allograft and/or autograft to facilitate fusion and its participants represented patients with noteworthy comorbidities, including high BMI, diabetes, and current/former smokers. Among subjects with radiographs at 12 ± 3 months, nearly all (56 of 58 patients, or 96.6%, and 75 of 77 levels, or 97.4%) achieved fusion based on Bridwell-Lenke grading. 

Among 45 evaluable subjects, 71% (32 patients) achieved clinically significant improvements in VAS leg pain, and 76% (34 patients) achieved clinically significant improvements in VAS back pain. Additionally, there were no (0%) reported device-related adverse events (AEs). 

According to their press release, common device-related AEs associated with interbody fusion devices include, but are not limited to, subsidence, displacement, and nerve injury. The incidence rate for non-device-related AEs was consistent with other PLIF/TLIF studies. There were no (0%) observations of cage subsidence (defined as an overlap between the vertebral endplates and the device exceeding 25% of the device height) and only one case (1.7%) of observed device migration (defined as displacement of the device relative to the position within intra-operative or immediate post-operative images). Analysis of that case reveals that the cage moved only slightly within the disc space and the patient went on to fuse.

Coric notes, “This study adds to the evidence base supporting the safe and effective use of expandable interbody spacers in the treatment of lumbar spine diseases. The FlareHawk implant’s ability to expand in both cephalad-caudal and lateral-medial planes is especially advantageous for decreasing neural retraction while maximizing vertebral body endplate coverage and fusion area.”


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