The clinical and radiological outcomes of multilevel minimally invasive transforaminal lumbar interbody fusion

PURPOSE: To investigate the clinical and radiological outcomes of multilevel minimally invasive transforaminal lumbar interbody fusion (MITLIF) in multilevel degenerative lumbar diseases. METHODS: Of 172 patients who could be followed-up for at least 1 year after undergoing a MITLIF, a total of 127 patients in whom unilateral cages were used through a unilateral approach (consisting of 69 patients for single-level, 40 for two-level, and 18 for three- or higher-level) were retrospectively studied as subjects. In this study, clinical assessment parameters included Visual Analog Scale (VAS) score and Oswestry Disability Index (ODI), while radiologic assessment parameters included disc height, segmental lordotic angle, and lumbar lordotic angle. At the last follow-up, the level of bone fusion was determined in accordance with the Brantigan and Steffee criteria for classification of fusion results. RESULTS: The VAS scores of back pain and radiating leg pain tended to improve postoperatively, and showed no significant difference among groups (p > 0.05). In terms of ODI, the results of functional assessments also indicated no significant difference among groups (p > 0.05). Similarly, there was no statistically significant difference in disc height, segmental lordotic angle, lumbar lordotic angle, and bone fusion depending on the number of fusion levels (p > 0.05). CONCLUSIONS: Regardless of the number of fused levels, satisfactory clinical and radiological outcomes of MITLIF were seen in patients with spinal stenosis, which suggests that the said surgical procedure may be useful even for patients with multilevel spinal stenosis.