en Orthopedic Surgery Orthopedic Surgery Original Research Original Research <p> <strong> Background </strong>:The incidence of recurrence in patients undergoing primary discectomy due to lumbar disc herniation (LDH), is regularly reported as 5-15%. In this study we aimed to evaluate surgical outcome of instrumented transforaminal lumbar interbody fusion (TLIF) in the patients suffering from recurrent LDH. </p><p> <strong> Methods </strong>: We retrospectively studied 51 patients (30 female, 21 male) from August 2007 to October 2011. The mean age and follow-up of the patients was 46.4±14.8 (ranged 29-77 years old) and 31.4±6.8 (ranged 25-50 months), respectively. Clinical improvement was assessed by Oswestry Disability Index (ODI), visual analogue scale (VAS), and subjective satisfaction rate, while fusion was appraised radiologically. Data analysis was by one sample Kolmogorov-Smirnov, paired t, and Mann-Whitney tests. </p><p> <strong> Results </strong>: Surgery could significantly improve mean leg and lumbar VAS and ODI from preoperative 7.4±2.5, 7.8±3.1, and 72.1±21.5 to postoperative 3.4±3.6, 3.5±2.6, and 27.5±18.0, respectively at the last follow-up visit. Subjective satisfaction rate was excellent in 24 patients (47.1%), good in 14 (27.5%), fair 11 (21.6%), and poor in two (3.9%). We had one patient with iatrogenic partial L5 nerve root injury and one with unknown late onset refractory postoperative back pain. Fusion rate was 100% and instrument failure was nil. </p><p> <strong> Conclusion </strong>: In surgical treatment of the patients with recurrent LDH, bilaterally instrumented TLIF is a relatively safe and effective procedure and can be associated with least instrument failure and highest fusion rate while no postoperative bracing is also needed. </p><p> <strong> </strong></p> Transforaminal lumbar interbody fusion, Recurrent disc herniation, Treatment outcome. 823 828 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1569-6&slc_lang=en&sid=1 Farzad Omidi-Kashani omidif@mums.ac.ir 200319475328460013822 200319475328460013822 Yes Orthopedic Department, Orthopedic Research Center, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Ebrahim Ghayem Hasankhani hasankhanie@mums.ac.ir 200319475328460013823 200319475328460013823 No Orthopedic Department, Orthopedic Research Center, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Hamid Reza Noroozi noroozi_hr@yahoo.com 200319475328460013824 200319475328460013824 No Orthopedic Department, Orthopedic Research Center, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.