Wednesday, September 26, 2018 1:00 PM – 2:00 PM What's New in MIS: 42. Diminishing clinical returns of multilevel minimally invasive lumbar interbody fusion

Abstract

BACKGROUND CONTEXT Minimally invasive surgical (MIS) techniques for spinal fusion aim to reduce the morbidity and considerable soft-tissue damage associated with conventional open surgery. As longer, multilevel arthrodesis procedures are increasingly performed using MIS techniques, it is necessary to weigh the risks and benefits of multilevel MIS lumbar fusion as a function of fusion length. PURPOSE Investigate the relationship between number of levels fused and clinical outcomes in patients undergoing open and MIS lumbar fusion procedures. STUDY DESIGN/SETTING Retrospective clinical review at single institution. PATIENT SAMPLE A total of 437 patients undergoing lumbar interbody fusion by open or MIS technique. OUTCOME MEASURES Complication rates, length of stay (LOS), estimated blood loss (EBL) METHODS Patients undergoing RESULTS Included: 437 patients (57±13 years, 51% F, 29.5 kg/m2) undergoing lumbar interbody fusion(1.6±0.9 levels fused, 72% involved transforaminal approach, 18% anterior, 14% lateral). Overall breakdown of fusion length groups was: 64% 1-level, 21% 2-level, 16% 3+ level. By surgical technique, 37.5% of cases were MIS and 62.5% were open. Patients undergoing open surgery were older (58 years vs. 55, p=.022) with more comorbidities(mean CCI: 1.5 vs. 0.9, p .05). While periop complication rates were significantly lower for MIS patients at 1-level (16% vs. 29%, p=.012) and 2-levels (12% vs. 30%, p=.043), at 3+ levels, complication rates were comparable between MIS and open groups (38% vs. 36%, p=.921). Furthermore, despite no differences in rates of pulmonary and GI complications between MIS and open groups at 1-level and 2-levels (both p>.05), MIS patients undergoing 3+ level fusions had higher rates of ileus (13% vs. 0%, p=.003) and showed a trend of increased adverse pulmonary events (25% vs. 6%, p=.052). For all categories of fusion length, MIS procedures resulted in significantly less blood loss (all p CONCLUSIONS As compared to corresponding open surgeries, minimally invasive lumbar interbody fusions provided diminishing clinical returns for multilevel procedures. While MIS patients had lower rates of perioperative complications for 1- and 2-level fusions, 3+ level MIS fusions resulted in overall complication rates comparable to those of open patients, and higher rates of adverse pulmonary and ileus events. These results can be used to improve counseling of patients indicated for multilevel lumbar interbody fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.