CONFLICTS OF INTEREST: None. FUNDING SOURCES: Institute of Orthopaedics, Oswestry. http://dx.doi.org/10.1016/j.spinee.2014.12.040 Lumbar spinal stenosis with stable low grade spondylolisthesis - treatment alone with minimally invasive decompression - 2 year comparative outcomes. Y Raj Rampersaud, B Roy Chaudhary, R. Mannion, (Consultant Spinal Neurosurgeon); Department of Orthopaedics, Toronto Western Hospital, 399 Bathurst St, Toronto, Ontario M5T 2S8, Canada BACKGROUND CONTEXT: Lumbar spinal stenosis (LSS) is a common surgical spinal pathology with many patients having concurrent degenera- tive lumbar spondylolisthesis (DLS). Surgical decompression for DLS has historically been better with fusion, however recent advances question the need for fusion in selected patients. PURPOSE: Study objective was to assess surgical & patient reported out- comes following decompression alone in selected patients with DLS com- pared to those with no DLS. STUDY DESIGN/SETTING: A single surgeon consecutive series of pa- tients undergoing surgery for lumbar spinal stenosis with a minimum of 2 year follow up in prospective observational study. PATIENT SAMPLE: 157 patients (62 DLS/95 without DLS). OUTCOME MEASURES: Primary outcome measures were Oswestry Disability Index (ODI) scores & re-operation rates. Secondary outcomes were pre & postoperative leg and back pain VAS scores & satisfaction rat- ings post-surgery & time to reoperation. METHODS: Decompression alone was chosen for patients with neuro- genic claudication & no dynamic instability. All patients underwent bilat- eral decompression via a unilateral minimally invasive approach. RESULTS: Both cohorts were comparable for age & pre-operative ODI. There was significant ODI improvement in both cohorts (DLS mean baseline ODI improved from 40 to 23 at 2 years [p!0.01] & in noDLS from 39 to 26 [p !0.01]). The change in ODI was comparable in the two cohorts (p50.18). CONCLUSIONS: Using the aforementioned selection criteria DLS pa- tients undergoing decompression alone have excellent intermediate term results comparable to LSS patients without DLS thus avoiding fusion operation. CONFLICTS OF INTEREST: None. FUNDING SOURCES: Institute of Orthopaedics, Oswestry. http://dx.doi.org/10.1016/j.spinee.2014.12.041 Results of LLIF with Avenue L cage in lumbar degenerative disease Charlie Bouthors, Charles-Henri Flouzat Lachaniette, Alexandre Poignard, Jer^ome Allain; H^opital Henri Mondor (Creteil, France) BACKGROUND CONTEXT: The aim of minimally-invasive surgery is to reduce surgical morbidity with same rate of success than open procedures. PURPOSE: To assess clinical outcomes and radiographic changes after minimally-invasive Lateral Lumbar Interbody Fusion. STUDY DESIGN/SETTING: A monocentric retrospective study in- cluded all patients treated by LLIF performed for lumbar degenerative disc disease, spondylolisthesis and degenerative scoliosis. Data were collected prospectively. OUTCOME MEASURES: Clinical outcomes were assessed at one year according to Visual Analogic Scale (VAS) lumbar/radicular, Oswestry Dis- ability Index (ODI), Short-Form 36 mental and physical (SF-36). The ra- diographic measurements were taken to assess change in the sagittal and coronal plane alignment. Fusion was analysed at 1 year with a CT scan. RESULTS: From 2010 to 2013, 60 patients underwent 74 LLIF. Mean fol- low-up was 19 months. Mean surgical duration and blood loss were respec- tively 141 min and 152 ml. EVA L/R and ODI were decreased of 57%, 66% and 49% (p!0,01) and SF-36 M/P increase of 62%/83% (p!0,01). There were a mean gain of 5  of regional lordosis (p!0,01) and 5 mm of disc height (p!0,001). Sagittal Vertical Axis decreased from 29 mm to 10 mm (p!0,001). Mean Cobb scoliosis angle and spondylolisthesis correction were respectively 62% (p!0,01) and 64% (p!0,01). 2 perioperative verte- bral body fractures were reported. 8 patients experienced postoperative sen- sory deficit and 1 motor deficit that all recovered. Fusion rate was 87,5%. 2 patients required additional posterior decompression and fusion. CONCLUSIONS: LLIF is effective in lumbar degenerative disease in cor- recting the coronal plane deformity and gaining lordosis. Excellent clinical outcomes are obtained with few complications. CONFLICTS OF INTEREST: Royalties (LDR medical). FUNDING SOURCES: None. http://dx.doi.org/10.1016/j.spinee.2014.12.042 Can we predict recurrence following microdiscectomy? Fabian Wong, Sarah Ferguson, Otto Von Arx, Maurice Paterson; Spinal Unit, Royal United Hospital, Bath BACKGROUND CONTEXT: Microdiscectomy of the lumbar spine is commonly performed spinal for radiculopathy secondary to symmetric disc prolapse of the lumbar spine without causing cauda equine syndrome. Unfortunately it is also known that lumbar disc prolapse at the same level and side may recur subsequent to the surgery at a variable interval. How- ever, there is limited evidence to demonstrate factors that could predict the risk of recurrence. PURPOSE: The aim of this study is to evaluate lumbar spine interverte- bral discs characteristics, and their association with recurrence of disc pro- lapse following primary microdiscectomy. STUDY DESIGN/SETTING: Retrospective Cohort Study. PATIENT SAMPLE: Consecutive patients who underwent primary mi- crodiscectomy at a single spinal unit in over a 3-year period were reviewed and included in this study. OUTCOME MEASURES: Recurrence. METHODS: Patient demographics, clinical documents, and images in- cluding pre- and post-operative MRI scans were reviewed. Pre-operative Images were assessed by a single consultant spinal surgeon who was blinded to the presence of recurrence of the disc prolapse. RESULTS: 131 patients who underwent primary microdiscectomy were identified and included. 15 patients developed symptomatic recurrence of disc prolapse at the same level and side. 10 of these patients subse- quently underwent revision microdiscectomy. There was a trend between rate of recurrence and the preservation of normal disc signal and intra-nu- clear septum of the prolapsed disc at primary procedure. CONCLUSIONS: Our rate of recurrence was 11%. Characteristics of the prolapse disc on pre-operative images may provide information on the risk of recurrence following the primary procedure. Further study with larger population is required to further assess these relationships. CONFLICTS OF INTEREST: None. FUNDING SOURCES: None. http://dx.doi.org/10.1016/j.spinee.2014.12.043 Basic Science/Spinal Surgery Quality improvement project the effect of an enhanced recovery programme on length of stay and patient experience following elective spinal surgery at Musgrove Park Hospital Alex Goubran, Matthew Beebee, Lorraine Sandford, Sarah Woodhill, Emma Palfreman, Yee Leung, Pradeep Madhavan, Paul Thorpe, Michael Walburn; Musgrove Park Hospital, Musgrove Road, Taunton, Somerset TA1 5DA BACKGROUND CONTEXT: Enhanced recovery in arthroplasty surgery has demonstrated that with careful pre-operative planning, engagement and 55S Proceedings of the BASS 2015 Bath Meeting / The Spine Journal 15 (2015) 50S–85S