• Chi Heon Kim, Chun Kee Chung, Yunhee Choi, Sukyoun Shin, Myo Jeong Kim, Juhee Lee, and Byung Joo Park.
• *Department of Neurosurgery, Seoul National University Hospital, Seoul, South Korea †Department of Neurosurgery, Seoul National University College of Medicine, Seoul, South Korea ‡Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, South Korea §Clinical Research Institute, Seoul National University Hospital, Seoul, South Korea ¶Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, South Korea ∥Division of Medical Statistics, Medical Research Collaborating Center, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea **Health Insurance Review and Assessment Service, Seoul, Korea; and ††Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.
• Spine. 2015 Oct 1; 40 (19): E1063-70.

Study DesignRetrospective cohort study.ObjectiveTo provide an age cut-off of percutaneous endoscopic lumbar discectomy (PELD) for optimal reoperation rate with nationwide population-based data.Summary Of Background DataOpen discectomy is the standard operation for lumbar herniated intervertebral disk disease (HIVD). PELD has shown noninferior outcome to open discectomy and there is increasing interest with regard to PELD. However, PELD may not be a suitable option for all age groups.MethodsWe selected 15,817 patients who underwent open discectomy (n = 12,816) or PELD (n = 3001) in 2003 from the Korean Health Insurance Review & Assessment Service (HIRA) database. All patients in the cohort were followed until December 31, 2008, and the minimum follow-up period was 5 years. A time-to-event survival analysis was conducted. The primary endpoint was any type of second lumbar spine surgery during the follow-up period. Minimum P-value approach and a 2-fold cross-validation approach were utilized to determine an age cut-off point.ResultsThe optimal age cut-off point was determined as 57 years. PELD for older patients (≥57 years) had a higher reoperation risk during the postoperative 3.4 years (hazard ratio [HR] at 1 yr, 1.75; 2 yr, 1.57; and 3 yr, 1.41). However, the reoperation risk was not higher after PELD for patients younger than 57 years, from 1.9 years, than open discectomy (HR at 2 yr, 0.86; 3 yr, 0.78; 4 yr, 0.70; and 5 yr, 0.63).ConclusionIn the present study, we showed that an age cut-off point of PELD for optimal reoperation rate may be 57 years, based on nationwide population-based data. The reoperation rate does not seem to be higher for patients younger than 57 years after PELD than after open discectomy; however, PELD for older patients should be applied after careful consideration.Level Of Evidence3.

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