BACKGROUND: Although posterior lumbar interbody fusion (PLIF) has provided satisfactory clinical outcomes, adjacent segment disease (ASD) is one of the most important complications affecting long-term results. However, according to ASD studies, few have described repeat surgery. The purpose of this study was to elucidate incidence, time period, and clinical features of multiple-repeated ASD after PLIF. METHODS: Subjects comprised 1112 consecutive patients (502 men, 610 women) who underwent 1-level PLIF for degenerative lumbar diseases. The mean age of patients was 66 years (range, 15-89). The mean follow-up period was 6.4 years (range, 0.5-21.1). The incidence and the time period of multiple-repeated ASD were investigated. To elucidate clinical features of the multiple-repeated ASD, all 4 cases were shown as the case description including radiographic parameters. RESULTS: Four (0.4%) developed multiple-repeated ASD: 3 women and 1 man. Primary PLIF was performed at L3-4 in 1 patient and at L4-5 in 3 patients. Two patients underwent adjacent segment decompression simultaneously. All patients required at least 3 additional surgeries due to newly occurred ASD after each PLIF. All patients developed iatrogenic flatback as ASD was repeated. As a result, corrective surgeries were required (thoracolumbar, 2; spinopelvic, 2). CONCLUSIONS: Multiple-repeated ASD was observed in 0.4% of the patients. All patients developed iatrogenic flatback as a result of repeated ASD, and corrective surgeries were required for these patients.
BACKGROUND: Although posterior lumbar interbody fusion (PLIF) has provided satisfactory clinical outcomes, adjacent segment disease (ASD) is one of the most important complications affecting long-term results. However, according to ASD studies, few have described repeat surgery. The purpose of this study was to elucidate incidence, time period, and clinical features of multiple-repeated ASD after PLIF. METHODS: Subjects comprised 1112 consecutive patients (502 men, 610 women) who underwent 1-level PLIF for degenerative lumbar diseases. The mean age of patients was 66 years (range, 15-89). The mean follow-up period was 6.4 years (range, 0.5-21.1). The incidence and the time period of multiple-repeated ASD were investigated. To elucidate clinical features of the multiple-repeated ASD, all 4 cases were shown as the case description including radiographic parameters. RESULTS: Four (0.4%) developed multiple-repeated ASD: 3 women and 1 man. Primary PLIF was performed at L3-4 in 1 patient and at L4-5 in 3 patients. Two patients underwent adjacent segment decompression simultaneously. All patients required at least 3 additional surgeries due to newly occurred ASD after each PLIF. All patients developed iatrogenic flatback as ASD was repeated. As a result, corrective surgeries were required (thoracolumbar, 2; spinopelvic, 2). CONCLUSIONS: Multiple-repeated ASD was observed in 0.4% of the patients. All patients developed iatrogenic flatback as a result of repeated ASD, and corrective surgeries were required for these patients.