Emily M Lindley1, Cameron Barton2, Thomas Blount2, Evalina L Burger2, Christopher M J Cain2, Howard B Seim3, A Simon Turner3, Vikas V Patel2. 1. Department of Orthopedics, University of Colorado, Anschutz Medical Campus, 13001 E. 17th Place, Mail Stop F432, Aurora, CO, 80045, USA. emily.lindley@ucdenver.edu. 2. Department of Orthopedics, University of Colorado, Anschutz Medical Campus, 13001 E. 17th Place, Mail Stop F432, Aurora, CO, 80045, USA. 3. Department of Clinical Sciences, Colorado State University, College of Veterinary Medicine & Biomedical Sciences, Ft. Collins, CO, USA.
Abstract
PURPOSE: The ovine model is often used to evaluate new spine fusion technologies prior to clinical testing. An important aspect of designing sheep surgery protocols is to select the appropriate postoperative time period for comparing fusion outcomes. Unfortunately, determining the ideal study endpoint is complicated by the fact that prior published studies have not used consistent timeframes. Thus, the primary aim of this study was to provide a reference for investigators as to the expected fusion outcomes of control groups at varying timepoints in sheep spine surgery models. METHODS: We identified published sheep fusion studies using autograft, interbody cages, and/or instrumentation. Fusion data were extracted, converted to a common scale, and analyzed across studied timepoints. RESULTS: Overall, 29 studies of 360 fusion levels were identified: 11 ALIF (158 levels), 3 PLIF/TLIF (28 levels), 8 PLF (90 levels), and 7 ACDF (84 levels). Studied timepoints ranged from 4 to 48 weeks postoperative. In general, fusion rates varied across techniques and instrumentation. The time to reach solid fusion differed by as many as 20 weeks between control groups. CONCLUSIONS: Recommended timeframes for future studies designed to show either superiority over controls or equivalent outcomes with controls were developed based on aggregate results. Designating ideal study endpoints for sheep fusion models has both ethical implications associated with responsible use of animals in research, and economic implications given the cost of animal research. The current results can guide the development of future research methods and help investigators choose appropriate study timelines for various control groups.
PURPOSE: The ovine model is often used to evaluate new spine fusion technologies prior to clinical testing. An important aspect of designing sheep surgery protocols is to select the appropriate postoperative time period for comparing fusion outcomes. Unfortunately, determining the ideal study endpoint is complicated by the fact that prior published studies have not used consistent timeframes. Thus, the primary aim of this study was to provide a reference for investigators as to the expected fusion outcomes of control groups at varying timepoints in sheep spine surgery models. METHODS: We identified published sheep fusion studies using autograft, interbody cages, and/or instrumentation. Fusion data were extracted, converted to a common scale, and analyzed across studied timepoints. RESULTS: Overall, 29 studies of 360 fusion levels were identified: 11 ALIF (158 levels), 3 PLIF/TLIF (28 levels), 8 PLF (90 levels), and 7 ACDF (84 levels). Studied timepoints ranged from 4 to 48 weeks postoperative. In general, fusion rates varied across techniques and instrumentation. The time to reach solid fusion differed by as many as 20 weeks between control groups. CONCLUSIONS: Recommended timeframes for future studies designed to show either superiority over controls or equivalent outcomes with controls were developed based on aggregate results. Designating ideal study endpoints for sheep fusion models has both ethical implications associated with responsible use of animals in research, and economic implications given the cost of animal research. The current results can guide the development of future research methods and help investigators choose appropriate study timelines for various control groups.
Authors: Blake P Sherman; Emily M Lindley; A Simon Turner; Howard B Seim; James Benedict; Evalina L Burger; Vikas V Patel Journal: Eur Spine J Date: 2010-08-09 Impact factor: 3.134
Authors: Matti Scholz; Philipp Schleicher; Tanja Eindorf; Frank Friedersdorff; Michael Gelinsky; Ulla König; Andreas Sewing; Norbert P Haas; Frank Kandziora Journal: Spine (Phila Pa 1976) Date: 2010-04-01 Impact factor: 3.468
Authors: Frank Kandziora; Robert Pflugmacher; Matti Scholz; Tanja Eindorf; Klaus J Schnake; Norbert P Haas Journal: Spine (Phila Pa 1976) Date: 2004-09-01 Impact factor: 3.468
Authors: Tony Goldschlager; Peter Ghosh; Andrew Zannettino; Mark Williamson; Jeffrey Victor Rosenfeld; Silviu Itescu; Graham Jenkin Journal: Neurosurgery Date: 2011-04 Impact factor: 4.654
Authors: Slobodan Vukicevic; Lovorka Grgurevic; Igor Erjavec; Marko Pecin; Tatjana Bordukalo-Niksic; Nikola Stokovic; Marija Lipar; Hrvoje Capak; Drazen Maticic; Reinhard Windhager; T Kuber Sampath; Munish Gupta Journal: J Tissue Eng Regen Med Date: 2019-11-10 Impact factor: 3.963