Abstract
Introduction
Osteoporosis is not only responsible for an increased number of metaphyseal and spinal fractures but it also complicates their treatment. To prevent the initial loosening, we developed a new implant with an enlarged implant/bone interface based on the concept of perforated, hollow cylinders. We evaluated whether osseointegration of a hollow cylinder based implant takes place in normal or osteoporotic bone of sheep under functional loading conditions during anterior stabilization of the lumbar spine.
Materials and methods
Osseointegration of the cylinders and status of the fused segments (ventral corpectomy, replacement with iliac strut, and fixation with testing implant) were investigated in six osteoporotic (age 6.9 ± 0.8 years, mean body weight 61.1 ± 5.2 kg) and seven control sheep (age 6.1 ± 0.2 years, mean body weight 64.9 ± 5.7 kg). Osteoporosis was introduced using a combination protocol of ovariectomy, high-dose prednisone, calcium and phosphor reduced diet and movement restriction. Osseointegration was quantified using fluorescence and conventional histology; fusion status was determined using biomechanical testing of the stabilized segment in a six-degree-of-freedom loading device as well as with radiological and histological staging.
Results
Intact bone trabeculae were found in 70% of all perforations without differences between the two groups (P = 0.26). Inside the cylinders, bone volume/total volume was significantly higher than in the control vertebra (50 ± 16 vs. 28 ± 13%) of the same animal (P<0.01), but significantly less (P<0.01) than in the near surrounding (60 ± 21%). After biomechanical testing as described in Sect. ”Materials and methods”, seven spines (three healthy and four osteoporotic) were classified as completely fused and six (four healthy and two osteoporotic) as not fused after a 4-month observation time. All endplates were bridged with intact trabeculae in the histological slices.
Conclusions
The high number of perforations, filled with intact trabeculae, indicates an adequate fixation; bridging trabeculae between adjacent endplates and tricortical iliac struts in all vertebrae indicates that the anchorage is adequate to promote fusion in this animal model, even in the osteoporotic sheep.
Similar content being viewed by others
References
Aldini NN, Fini M, Giavaresi G, Giardino R, Greggi T, Parisini P (2002) Pedicular fixation in the osteoporotic spine: a pilot in vivo study on long-term ovariectomized sheep. J Orthop Res 20:1217–1224
Aspenberg P, Goodman S, Toksvig-Larsen S, Ryd L, Albrektsson T (1992) Intermittent micromotion inhibits bone ingrowth. Titanium implants in rabbits. Acta Orthop Scand 63:141–145
Baramki HG, Papin P, Steffen T (2000) A surgical approach to the ventral aspect of the lumbar vertebrae in the sheep model. Surg Radiol Anat 22:25–27
Branemark PI (1983) Osseointegration and its experimental background. J Prosthet Dent 50:399–410
Chao EY, Inoue N, Koo TK, Kim YH (2004) Biomechanical considerations of fracture treatment and bone quality maintenance in elderly patients and patients with osteoporosis. Clin Orthop 8:12–25
Cornell CN (2003) Internal fracture fixation in patients with osteoporosis. J Am Acad Orthop Surg 11:109–119
Craven TG, Carson WL, Asher MA, Robinson RG (1994) The effects of implant stiffness on the bypassed bone mineral density and facet fusion stiffness of the canine spine. Spine 19:1664–1673
Curtis R, Goldhahn J, Schwyn R, Regazzoni P, Suhm N (2005) Fixation principles in metaphyseal bone—a patent based review. Osteoporos Int 16(Suppl. 2):S54–S64
Egermann M, Goldhahn J, Schneider E (2005) Animal models for fracture treatment in osteoporosis. Osteoporos Int 16(Suppl 2):S129–S138
Epstein NE, Dickerman RD (2002) Delayed iliac crest autograft fractures following plated single-level anterior cervical corpectomy with fusion. J Spinal Disord Tech 15:420–424
Ferguson SJ, Winkler F, Nolte LP (2002) Anterior fixation in the osteoporotic spine: cut-out and pullout characteristics of implants. Eur Spine J 11:527–534
Goldhahn J, Jenet A, Schneider E, Christoph AL (2005) Slow rebound of cancellous bone after mainly steroid-induced osteoporosis in ovariectomized sheep. J Orthop Trauma 19:23–28
Goldhahn J, Reinhold M, Stauber M, Knop C, Frei R, Schneider E, Linke B (2006) Improved anchorage in osteoporotic vertebrae with new implant designs. J Orthop Res 24:917–925
Huntington CF, Murrell WD, Betz RR, Cole BA, Clements DH 3rd, Balsara RK (1998) Comparison of thoracoscopic and open thoracic discectomy in a live ovine model for anterior spinal fusion. Spine 23:1699–1702
Ito K, Hungerbuhler R, Wahl D, Grass R (2001) Improved intramedullary nail interlocking in osteoporotic bone. J Orthop Trauma 15:192–196
Kanayama M, Cunningham BW, Weis JC, Parker LM, Kaneda K, McAfee PC (1998) The effects of rigid spinal instrumentation and solid bony fusion on spinal kinematics. A posterolateral spinal arthrodesis model. Spine 23:767–773
Knoller SM, Meyer G, Eckhardt C, Lill CA, Schneider E, Linke B (2005) Range of motion in reconstruction situations following corpectomy in the lumbar spine: a question of bone mineral density? Spine 30:E229–E235
Kossmann T, Ertel W, Platz A, Trentz O (1999) Combined surgery for fractures of the thoraco-lumbar junction using the inlay-span method. Orthopade 28:432–440
Lill CA, Fluegel AK, Schneider E (2000) Sheep model for fracture treatment in osteoporotic bone: a pilot study about different induction regimens. J Orthop Trauma 14:559–565; discussion 565–566
Lill CA, Gerlach UV, Eckhardt C, Goldhahn J, Schneider E (2002) Bone changes due to glucocorticoid application in an ovariectomized animal model for fracture treatment in osteoporosis. Osteoporos Int 13:407–414
Lim TH, An HS, Hasegawa T, McGrady L, Hasanoglu KY, Wilson CR (1995) Prediction of fatigue screw loosening in anterior spinal fixation using dual energy x-ray absorptiometry. Spine 20:2565–2568
Linke B, Sellenschloh K, Huber G, Schneider E, Veltin U (1998) A new method of pre-clinical spine implant testing in six degrees of freedom—based on the hexapod principle. J Biomech 31(S1):41
Linke B, Meyer G, Knöller S, Schneider E (2002) Influence of preload in flexibility testing of native and instrumented lumbar spine specimens. In: Melkerson MN, Griffith SL, Kirkpatrick JS (eds) Spinal implants: are we evaluating them properly, ASTM STP 1431. American Society for Testing and Materials, West Conshohocken
Matsumoto T, Nakayama K, Kodama Y, Fuse H, Nakamura T, Fukumoto S (1998) Effect of mechanical unloading and reloading on periosteal bone formation and gene expression in tail-suspended rapidly growing rats. Bone 22:89S–93S
McLain RF, Yerby SA, Moseley TA (2002) Comparative morphometry of L4 vertebrae: comparison of large animal models for the human lumbar spine. Spine 27:E200–E206
Nagel DA, Kramers PC, Rahn BA, Cordey J, Perren SM (1991) A paradigm of delayed union and nonunion in the lumbosacral joint. A study of motion and bone grafting of the lumbosacral spine in sheep. Spine 16:553–559
Prendergast PJ, Huiskes R, Soballe K (1997) ESB Research Award 1996. Biophysical stimuli on cells during tissue differentiation at implant interfaces. J Biomech 30:539–548
Rahn BA (1999) Intra vitam staining techniques. Taylor & Francis, Philadelphia
Riggs BL, Melton LJ 3rd (1995) The worldwide problem of osteoporosis: insights afforded by epidemiology. Bone 17:505S–511S
Sanden B, Olerud C, Johansson C, Larsson S (2001) Improved bone–screw interface with hydroxyapatite coating: an in vivo study of loaded pedicle screws in sheep. Spine 26:2673–2678
Sawin PD, Dickman CA, Crawford NR, Melton MS, Bichard WD, Sonntag VK (2001) The effects of dexamethasone on bone fusion in an experimental model of posterolateral lumbar spinal arthrodesis. J Neurosurg 94:76–81
Schroeder A, Pohler O, Sutter F (1976) Gewebsreaktion auf ein Titan-Hohlzylinderimplantat mit Titan-Spritzschichtoberflache. SSO Schweiz Monatsschr Zahnheilkd 86:713–727
Smit TH (2002) The use of a quadruped as an in vivo model for the study of the spine—biomechanical considerations. Eur Spine J 11:137–144
Steffen T, Marchesi D, Aebi M (2000) Posterolateral and anterior interbody spinal fusion models in the sheep. Clin Orthop 371:28–37
Steinemann SG, Eulenberger J, Mäusli PA, Schröder A (2002) Adhesion of bone to titanium. In: Christel P, Meunier A, Lee AJC (eds) Biological an biomechanical performance of biomaterials. Elsevier Science Publishers B.V., Amsterdam, pp. 409–414
Takata S, Yasui N (2001) Disuse osteoporosis. J Med Invest 48:147–156
Wilke HJ, Kettler A, Wenger KH, Claes LE (1997) Anatomy of the sheep spine and its comparison to the human spine. Anat Rec 247:542–555
Zdeblick TA, Shirado O, McAfee PC, deGroot H, Warden KE (1991) Anterior spinal fixation after lumbar corpectomy. A study in dogs. J Bone Joint Surg Am 73:527–534
Acknowledgments
The authors would like to thank U. Lanker and his team for professional animal care and B. Rahn and his team for their help with histology.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Goldhahn, J., Neuhoff, D., Schaeren, S. et al. Osseointegration of hollow cylinder based spinal implants in normal and osteoporotic vertebrae: a sheep study. Arch Orthop Trauma Surg 126, 554–561 (2006). https://doi.org/10.1007/s00402-006-0185-7
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00402-006-0185-7