Abstract
Purpose
Augmentation of pedicle screws is recommended in selected indications (for instance: osteoporosis). Generally, there are two techniques for pedicle screw augmentation: inserting the screw in the non cured cement and in situ-augmentation with cannulated fenestrated screws, which can be applied percutaneously. Most of the published studies used an axial pull out test for evaluation of the pedicle screw anchorage. However, the loading and the failure mode of pullout tests do not simulate the cranio-caudal in vivo loading and failure mechanism of pedicle screws. The purpose of the present study was to assess the fixation effects of different augmentation techniques (including percutaneous cement application) and to investigate pedicle screw loosening under physiological cyclic cranio-caudal loading.
Methods
Each of the two test groups consisted of 15 vertebral bodies (L1–L5, three of each level per group). Mean age was 84.3 years (SD 7.8) for group 1 and 77.0 years (SD 7.00) for group 2. Mean bone mineral density was 53.3 mg/cm3 (SD 14.1) for group 1 and 53.2 mg/cm3 (SD 4.3) for group 2. 1.5 ml high viscosity PMMA bone cement was used for all augmentation techniques. For test group 1, pedicles on the right side of the vertebrae were instrumented with solid pedicle screws in standard fashion without augmentation and served as control group. Left pedicles were instrumented with cannulated screws (Viper cannulated, DePuy Spine) and augmented. For test group 2 pedicles on the left side of the vertebrae were instrumented with cannulated fenestrated screws and in situ augmented. On the right side solid pedicle screws were augmented with cement first technique. Each screw was subjected to a cranio-caudal cyclic load starting at 20–50 N with increasing upper load magnitude of 0.1 N per cycle (1 Hz) for a maximum of 5000 cycles or until total failure. Stress X-rays were taken after cyclic loading to evaluate screw loosening.
Results
Test group 1 showed a significant higher number of load cycles until failure for augmented screws compared to the control (4030 cycles, SD 827.8 vs. 1893.3 cycles, SD 1032.1; p < 0.001). Stress X-rays revealed significant less screw toggling for the augmented screws (5.2°, SD 5.4 vs. 16.1°, SD 5.9; p < 0.001). Test group 2 showed 3653.3 (SD 934) and 3723.3 (SD 560.6) load cycles until failure for in situ and cement first augmentation. Stress X-rays revealed a screw toggling of 5.1 (SD 1.9) and 6.6 (SD 4.6) degrees for in situ and cement first augmentation techniques (p > 0.05).
Conclusion
Augmentation of pedicle screws in general significantly increased the number of load cycles and failure load comparing to the nonaugmented control group. For the augmentation technique (cement first, in situ augmented, percutaneously application) no effect could be exhibited on the failure of the pedicle screws. By the cranio-caudal cyclic loading failure of the pedicle screws occurred by screw cut through the superior endplate and the characteristic “windshield-wiper effect”, typically observed in clinical practice, could be reproduced.
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References
Office GFS (2002–2010) Total cost of illness in millions of Euro. Classification: years, gender, ICD10, provider (Primary source: Federal Statistical Office, Total Health Expenditure, Statistics). In., Berlin
Masala S, Lunardi P, Fiori R, Liccardo G, Massari F, Ursone A, Simonetti G (2004) Vertebroplasty and kyphoplasty in the treatment of malignant vertebral fractures. J Chemother 16(Suppl 5):30–33
Melton LJ 3rd, Thamer M, Ray NF, Chan JK, Chesnut CH 3rd, Einhorn TA, Johnston CC, Raisz LG, Silverman SL, Siris ES (1997) Fractures attributable to osteoporosis: report from the National Osteoporosis Foundation. J Bone Mineral Res 12:16–23. doi:10.1359/jbmr.1997.12.1.16
Papaioannou A, Watts NB, Kendler DL, Yuen CK, Adachi JD, Ferko N (2002) Diagnosis and management of vertebral fractures in elderly adults. Am J Med 113:220–228
Becker S, Chavanne A, Spitaler R, Kropik K, Aigner N, Ogon M, Redl H (2008) Assessment of different screw augmentation techniques and screw designs in osteoporotic spines. Eur Spine Jy 17:1462–1469. doi:10.1007/s00586-008-0769-8
Burval DJ, McLain RF, Milks R, Inceoglu S (2007) Primary pedicle screw augmentation in osteoporotic lumbar vertebrae: biomechanical analysis of pedicle fixation strength. Spine 32:1077–1083. doi:10.1097/01.brs.0000261566.38422.40
Chen LH, Tai CL, Lai PL, Lee DM, Tsai TT, Fu TS, Niu CC, Chen WJ (2009) Pullout strength for cannulated pedicle screws with bone cement augmentation in severely osteoporotic bone: influences of radial hole and pilot hole tapping. Clin Biomech (Bristol, Avon) 24:613–618. doi:10.1016/j.clinbiomech.2009.05.002
Frankel BM, D’Agostino S, Wang C (2007) A biomechanical cadaveric analysis of polymethylmethacrylate-augmented pedicle screw fixation. J Neurosurg Spine 7:47–53. doi:10.3171/SPI-07/07/047
Zindrick MR, Wiltse LL, Widell EH, Thomas JC, Holland WR, Field BT, Spencer CW (1986) A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine. Clin Orthop Relat Res (203):99–112
Rohlmann A, Bergmann G, Graichen F (1997) Loads on an internal spinal fixation device during walking. J Biomech 30:41–47
Rohlmann A, Bergmann G, Graichen F, Weber U (1997) Comparison of loads on internal spinal fixation devices measured in vitro and in vivo. Med Eng Phys 19:539–546
Rohlmann A, Graichen F, Bergmann G (2000) Influence of load carrying on loads in internal spinal fixators. J Biomech 33:1099–1104
Wu JC, Chen CS, Yip SW, Hsu ML (2012) Stress distribution and micromotion analyses of immediately loaded implants of varying lengths in the mandible and fibular bone grafts: a three-dimensional finite element analysis. Int J Oral Maxillofac Implants 27:e77–e84
Felsenberg D, Gowin W (1999) Bone densitometry by dual energy methods. Der Radiologe 39:186–193
Windolf M, Maza ER, Gueorguiev B, Braunstein V, Schwieger K (2010) Treatment of distal humeral fractures using conventional implants. Biomechanical evaluation of a new implant configuration. BMC Musculoskelet Disord 11:172. doi:10.1186/1471-2474-11-172
Unger S, Erhart S, Kralinger F, Blauth M, Schmoelz W (2012) The effect of in situ augmentation on implant anchorage in proximal humeral head fractures. Injury 43:1759–1763. doi:10.1016/j.injury.2012.07.003
Kiner DW, Wybo CD, Sterba W, Yeni YN, Bartol SW, Vaidya R (2008) Biomechanical analysis of different techniques in revision spinal instrumentation: larger diameter screws versus cement augmentation. Spine 33:2618–2622. doi:10.1097/BRS.0b013e3181882cac
Goel VK, Winterbottom JM, Weinstein JN (1994) A method for the fatigue testing of pedicle screw fixation devices. J Biomech 27:1383–1388
Law M, Tencer AF, Anderson PA (1993) Caudo-cephalad loading of pedicle screws: mechanisms of loosening and methods of augmentation. Spine 18:2438–2443
Kueny RA, Kolb JP, Lehmann W, Puschel K, Morlock MM, Huber G (2014) Influence of the screw augmentation technique and a diameter increase on pedicle screw fixation in the osteoporotic spine: pullout versus fatigue testing. Eur Spine J. doi:10.1007/s00586-014-3476-7
Fan H, Zhang R, Shen C, Dong F, Li Y, Song P, Gong C, Wang Y (2000) The biomechanical properties of pedicle screw fixation combined with trajectory bone cement augmentation in osteoporotic vertebrae. J Spin Disord Tech. doi:10.1097/BSD.1090b1013e3182a14870
Pesenti S, Blondel B, Peltier E, Adetchessi T, Dufour H, Fuentes S (2014) Percutaneous cement-augmented screws fixation in the fractures of the aging spine: is it the solution? BioMed Res Int 2014:610675. doi:10.1155/2014/610675
Bullmann V, Schmoelz W, Richter M, Grathwohl C, Schulte TL (2010) Revision of cannulated and perforated cement-augmented pedicle screws: a biomechanical study in human cadavers. Spine 35:E932–E939. doi:10.1097/BRS.0b013e3181c6ec60
Choma TJ, Pfeiffer FM, Swope RW, Hirner JP (2012) Pedicle screw design and cement augmentation in osteoporotic vertebrae: effects of fenestrations and cement viscosity on fixation and extraction. Spine 37:E1628–E1632. doi:10.1097/BRS.0b013e3182740e56
Sarzier JS, Evans AJ, Cahill DW (2002) Increased pedicle screw pullout strength with vertebroplasty augmentation in osteoporotic spines. J Neurosurg 96:309–312
Cook SD, Salkeld SL, Stanley T, Faciane A, Miller SD (2004) Biomechanical study of pedicle screw fixation in severely osteoporotic bone. Spine J 4:402–408. doi:10.1016/j.spinee.2003.11.010
Rohlmann A, Graichen F, Weber U, Bergmann G (2000) 2000 Volvo Award winner in biomechanical studies: monitoring in vivo implant loads with a telemeterized internal spinal fixation device. Spine 25:2981–2986
Rohlmann A, Bergmann G, Graichen F (1999) Loads on internal spinal fixators measured in different body positions. Eur Spine J 8:354–359
Conflict of interest
The study was supported by DePuy Spine Germany (receiving the implants, cement, and laboratory cost, no wages have been paid), but none of the authors has any potential conflict of interest.
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An erratum to this article is available at http://dx.doi.org/10.1007/s00586-015-4001-3.
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Bostelmann, R., Keiler, A., Steiger, H.J. et al. Effect of augmentation techniques on the failure of pedicle screws under cranio-caudal cyclic loading. Eur Spine J 26, 181–188 (2017). https://doi.org/10.1007/s00586-015-3904-3
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DOI: https://doi.org/10.1007/s00586-015-3904-3