First results of multicortical screw anchoring compared with conventional bicortical screw placement in the sacrum: A biomechanical investigation of a new screw design


      • Sacral bicortical screw fixation is commonly used for strength and stability.
      • This study tested a new, multicortical screw fixation technique.
      • Fresh-frozen sacrums were used to compare bicortical and multicortical techniques.
      • Multicortical screw fixation resulted in more strength, stability and load bearing.



      Bicortical screw fixation is an established technique to increase screw strength in vertebral bodies, although it is associated with several complications, for example screw-loosening. Cement augmentation can increase stability of screw-fixation but can also cause various complications, such as cement-leakage or cement embolism. In this study, we tested a new, multicortical screw fixation technique in the sacrum.


      Four fresh-frozen sacrums were used. In group 1, standard screw insertion, with sagittal parallel and axial convergent screw-drive was performed. In group 2, the screw-drive of the first screw was similar to the screw-drive in group 1. In addition, a second screw was inserted descending into the intended hole in the head of the screw and at a stable angle. Therefore, the screws of the multiloc humerus nail-system (Synthes) were used. The specimens were connected to a testing-machine and underwent cyclic axial loading with an increase in the load after each completed stage.


      Multicortical screw fixation leads to a significant increase in the number of completed cycles and a significantly increased load until failure.


      Multicortical screw fixation in the sacrum offers a stronger attachment of the screws. In the future, multicortical implants, which fulfil the criteria demanded in spine surgery, can offer higher stability and may decrease the loosening rates of the implanted screws.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Clinical Biomechanics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Breeze S.W.
        • Doherty B.J.
        • Noble P.S.
        • LeBlanc A.
        • Heggeness M.H.
        A biomechanical study of anterior thoracolumbar screw fixation.
        Spine. 1998; 23: 1829-1831
        • Bullmann V.
        • Schmoelz W.
        • Richter M.
        • Grathwohl C.
        • Schulte T.L.
        Revision of cannulated and perforated cement-augmented pedicle screws: a biomechanical study in human cadavers.
        Spine. 2010; 35: E932-E939
        • Erdem M.N.
        • Karaca S.
        • Sarı S.
        • Yumrukcal F.
        • Tanli R.
        • Aydogan M.
        Application of cement on strategic vertebrae in the treatment of the osteoporotic spine.
        Spine J. 2017; 17: 328-337
      1. Lehman Jr RA, Kuklo TR, Belmont Jr PJ, Andersen RC, Polly Jr DW. Advantage of pedicle screw fixation directed into the apex of the sacral promontory over bicortical fixation: a biomechanical analysis. Spine. 2002;27(8):806–11

        • Madigan L.
        • Vaccaro A.R.
        • Spector L.R.
        • Milam A.R.
        Management of symptomatic lumbar degenerative disk disease.
        J. Am. Acad. Orthop. Surg. 2009; 17 (Feb 1): 102-111
        • Mahato N.K.
        Pedicular anatomy of the first sacral segment in transitional variations of the lumbo-sacral junction.
        Spine. 2011; 36: E1187-E1192
        • McCord D.H.
        • Cunningham B.W.
        • Shono Y.
        • Myers J.J.
        • McAfee P.C.
        Biomechanical analysis of lumbosacral fixation.
        Spine. 1992; 17: S235-S243
        • Pesenti S.
        • Graillon T.
        • Mansouri N.
        • Adetchessi T.
        • Tropiano P.
        • Blondel B.
        • Fuentes S.
        Use of pedicle percutaneous cemented screws in the management of patients with poor bone stock.
        Neuro-Chirurgie. 2016; 62: 306-311
        • Polly Jr., D.W.
        • Orchowski J.R.
        • Ellenbogen R.G.
        Revision pedicle screws: bigger, longer shims-what is best?.
        Spine. 1998; 23: 1374-1379
        • Rohlmann A.
        • Bergmann G.
        • Graichen F.
        • Weber U.
        Loads on internal spinal fixation devices. Die Belastung des Wirbel-Fixateur-interne.
        Orthopade. 1999; 28: 451-457
        • Schmoelz W.
        • Heinrichs C.H.
        • Schmidt S.
        • Piñera A.R.
        • Tome-Bermejo F.
        • Duart J.M.
        • Bauer M.
        • Galovich L.Á.
        Timing of PMMA cement application for pedicle screw augmentation affects screw anchorage.
        Eur. Spine J. 2017; 26: 2883-2890
        • Shea T.M.
        • Laun J.
        • Gonzalez-Blohm S.A.
        • Doulgeris J.J.
        • Lee W.E.
        • Aghayev K.
        • Vrionis F.D.
        Designs and techniques that improve the pullout strength of pedicle screws in osteoporotic vertebrae: current status.
        Biomed. Res. Int. 2014; 2014
        • Topp T.
        • Müller T.
        • Huss S.
        • Kann P.H.
        • Weihe E.
        • Ruchholtz S.
        • Zettl R.P.
        Embalmed and fresh frozen human bones in orthopedic cadaveric studies: which bone is authentic and feasible? A mechanical study.
        Acta Orthop. 2012; 83: 543-547
        • Wagner D.
        • Kamer L.
        • Sawaguchi T.
        • Richards R.G.
        • Noser H.
        • Rommens P.M.
        Sacral bone mass distribution assessed by averaged three-dimensional CT models: implications for pathogenesis and treatment of fragility fractures of the sacrum.
        Joint Bone Joint Surg. Am. 2016; 98: 584-590
        • Weinstein J.N.
        • Rydevik B.L.
        • Rauschning W.
        Anatomic and technical considerations of pedicle screw fixation.
        Clin. Orthop. Relat. Res. 1992; 34-46
        • Zhuang X.M.
        • Yu B.S.
        • Zheng Z.M.
        • Zhang J.F.
        • Lu W.W.
        Effect of the degree of osteoporosis on the biomechanical anchoring strength of the sacral pedicle screws: an in vitro comparison between unaugmented bicortical screws and polymethylmethacrylate augmented unicortical screws.
        Spine. 2010; 35: E925-E931
        • Zindrick M.R.
        • Wiltse L.L.
        • Widell E.H.
        • Thomas J.C.
        • Holland W.R.
        • Field B.T.
        • Spencer C.W.
        A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine.
        Clin. Orthop. Relat. Res. 1986; : 99-112