Using more than two cages in adult spinal deformity patients produces significantly better correction, clinical outcomes and significantly fewer neurological complications, according to data shared at EUROSPINE 2015 (2–4 September, Copenhagen, Denmark).
Vincent Fière, Centre Orthopédique Santy, Lyon, France, told delegates that as well as promoting bony fusion and providing mechanical support, interbody cages also have lordosis restoration properties.
The authors reviewed 72 adult degenerative scoliosis or kyphosis patients treated between 2012 and 2014. Sixty of these patients (76.7% female with an average age of 61 years) with pre- and post-operative X-rays reached six-month follow up, with X-rays, Oswestry Disability Index (ODI) and Scoliosis Research Society-22 (SRS-22) scores collected at each follow-up visit. Of these 60, 33 had been implanted with more than two cages and 27 had been implanted with less than two. Fière noted that these two groups had similar baseline demographic and clinical parameters, with the exception of body mass index scores.
Fière reported that patients implanted with more than two cages had more Smith-Petersen osteotomy (87% of the >2 cage group compared with 59% of the <2 cage group, p=0.011). Fewer patients in the >2 cage group required bone morphogenic proteins (45.5%) to assist fusion than in the <2 cage group (77.7%) (p=0.011), while more >2 cage patients had fixation to sacrum/iliac (94%) than <2 cage patients (67%) (p=0.007).
In sagittal alignment, the two groups had similar relaxation of pelvic compensation and correction of global spinal alignment. However, patients with more than two cages implanted enjoyed significantly better pelvic incidence and lumbar lordosis correction (9 vs. 1.8 degrees in the <2 cage group, p=0.025) and significantly better coronal lumbar curve correction (15.4 vs. 4.9 degrees in the <2 cage group, p=0.003).
The benefits of more than two cages were also demonstrated by patients’ clinical scores. SRS-22 function improved by 0.58 in >2 cage patients compared with no improvement for <2 cage patients (p=0.006), SRS-22 pain improved by 1.01 vs. 0.21 (p=0.02) and overall SRS-22 score improved by 0.93 vs. 0.49 (p=0.044). For ODI scores, although the >2 cage patients did report a better ODI improvement that the <2 cage group (17.7 vs. 8.7), this was not statistically significant (p=0.119).
Significantly fewer perioperative complications were also reported in the >2 cage group (in 6.06% of patients) compared with the <2 cage group (29.6%) (p=0.015). The >2 cage group also reported a 0% incidence of dural tear, while the <2 cage group saw an 11% incidence (p=0.049).
Fière told delegates that, as the six-month follow up period only gave his team data for the short-term, the researchers are planning two-year follow ups to examine whether their hypothesis can be verified in the long-term.