How Risky Are Multi-level, MIS Lumbar Spine Fusions?

A multicenter team of researchers from New York have looked into the upsides and downsides of multilevel minimally invasive (MIS) lumbar fusion.

Their work, “Diminishing Clinical Returns of Multilevel Minimally Invasive Lumbar Interbody Fusion,” appears in the October 15, 2019 edition of Spine.

Co-author Peter Passias, M.D., with the NYU Langone Orthopedic Hospital, explained the underlying rationale behind this new study to OTW, “In the past five years, I have seen a rapid growth in multilevel arthrodesis procedures using minimally invasive surgery techniques. Increasingly, we are tackling more challenging cases with these approaches, yet the technology and our techniques have not had a chance to completely evolve with our ambitions.”

“With this being an up-and-coming approach, I wanted to assess the risks and benefits of multilevel MIS lumbar fusion as a function of fusion length relative to its initial single level applications.”

To understand the risks and benefits, the research team selected patients who were undergoing <4 level lumbar interbody fusion were stratified by surgical technique (MIS or open), and grouped by fusion length: 1-level, 2-levels, 3+ levels. They then collected demographic data, each patient’s Charlson Comorbidity Index (CCI), various surgical factors and perioperative complication rates and then compared the data for each of the technique groups at different fusion lengths using means comparison tests.

Dr. Passias summarized his results to OTW, “While MIS patients had lower rates of perioperative complications for 1- and 2- level fusions, 3+ level MIS fusions had comparable complication rates to open cases, and higher rates of adverse pulmonary and ileus events. Although that MIS patients sustained less intraoperative blood loss at all fusion lengths, at 3+ level fusions, MIS and open groups had similar rates of blood loss anemia.”

“As a whole, these results suggest that the key benefits of a minimally invasive surgical technique may be less advantageous for 3+ level lumbar interbody fusions, and there is a tendency towards the mean with open and MIS cases with regards to peri-operative outcomes.”

“Although on the surface, minimally invasive surgical techniques may aim to reduce risk to the patient, our study shows there may be a limitations and future development is needed. Surgeons should consider the parallel risk that 3+ MIS fusions and open procedures have on preoperative risk assessment.”