Minimally Invasive Interbody Fusion for Revision Lumbar Surgery Technical Feasibility and Safety

Study Design: Retrospective chart review of one surgeon's practice. Objective: We evaluate the perioperative morbidity of 43 patients undergoing minimally invasive lumbar interbody fusion to differentiate risks between primary and revision surgery candidates. Summary of Background Data: Minimally invasive approaches to the lumbar spine have rapidly evolved and the technical feasibility and safety of minimally invasive interbody fusion is well established. Revision surgery is technically more challenging and may cause avoidance of such approaches because of altered anatomy and absent bony landmarks. Description of minimally invasive surgery approaches among revision patients and the feasibility of such techniques demands clarification. Methods: Forty-three consecutive minimally invasive transforaminal lumbar interbody fusions (TLIFs) and posterior lumbar interbody fusions (PLIFs) were reviewed. Estimated blood loss, operative time, and complication rates were compared between primary and revision patients using Student t tests. Results: Seventeen revision surgery cases (40%) were compared with 26 primary surgeries (60%) to elucidate differences in operative time, estimated blood loss, and complications. Demographic variables were similar in both groups. Estimated blood loss trended higher among the PLIF group and among revision cases, though no statistical significance was observed. A higher rate of complications, most notably incidental durotomy, was observed among revision cases in both PLIF and TLIF patients. One patient undergoing primary surgery had an intraoperative pedicle fracture, and 1 patient undergoing revision surgery had an asymptomatic screw malposition. No patients had a major complication, nerve injury, infection, or conversion to an open procedure. Conclusions: Minimally invasive lumbar interbody fusion by revision surgery is technically feasible and is not associated with more blood loss or neurologic morbidity. However, revision surgery has a higher minor perioperative complication rate, particularly of incidental durotomy. These outcomes demand significant experience before attempting minimally invasive revision surgery in the lumbar spine.