title: Is polymethyl methacrylate a viable option for salvaging lateral mass screw failure in the subaxial cervical spine?
abstract: Study Design Biomechanical analysis of lateral mass screw pullout strength. Objective We compare the pullout strength of our bone cement-revised lateral mass screw with the standard lateral mass screw. Methods In cadaveric cervical spines, we simulated lateral mass screw "cutouts" unilaterally from C3 to C7. We salvaged fixation in the cutout side with polymethyl methacrylate (PMMA) or Cortoss cement (Orthovita, Malvern, Pennsylvania, United States), allowed the cement to harden, and then drilled and placed lateral mass screws back into the cement-augmented lateral masses. On the contralateral side, we placed standard lateral mass screws into the native, or normal lateral, masses and then compared pullout strength of the cement-augmented side to the standard lateral mass screw. For pullout testing, each augmentation group was fixed to a servohydraulic load frame and a specially designed pullout fixture was attached to each lateral mass screw head. Results Quick-mix PMMA-salvaged lateral mass screws required greater force to fail when compared with native lateral mass screws. Cortoss cement and PMMA standard-mix cement-augmented screws demonstrated less strength of fixation when compared with control-side lateral mass screws. Attempts at a second round of cement salvage of the same lateral masses led to more variations in load to failure, but quick-mix PMMA again demonstrated greater load to failure when compared with the nonaugmented control lateral mass screws. Conclusion Quick-mix PMMA cement revision equips the spinal surgeon with a much needed salvage option for a failed lateral mass screw in the subaxial cervical spine.
authors: Department of Orthopaedic Surgery, University of Missouri, Columbia, Missouri, United States.
authors: Michael A
authors: MA
authors: Gallizzi
authors: Austin Spine Center, Austin, Texas, United States.
authors: Craig A
authors: CA
authors: Kuhns
authors: Department of Orthopaedic Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States.
authors: Tyler J
authors: TJ
authors: Jenkins
authors: Department of Orthopaedic Surgery and Department of Bioengineering, University of Missouri Comparative Orthopaedic Laboratory, Columbia, Missouri, United States.
authors: Ferris M
authors: FM
authors: Pfeiffer
keywords: bone cement; cervical spine; lateral mass screw construct; posterior fixation; screw loosening; screw malpositioning; screw pullout testing
references: Clin Orthop Relat Res. 1993 Nov;(296):278-87
references: 8222439
references: Spine (Phila Pa 1976). 2004 Sep 1;29(17):1869-75
references: 15534407
references: J Neurosurg Spine. 2012 Mar;16(3):238-47
references: 22176430
references: J Neurosurg. 1994 Sep;81(3):341-9
references: 8057140
references: Spine (Phila Pa 1976). 1996 May 1;21(9):1037-44
references: 8724087
references: Spine J. 2004 Nov-Dec;4(6 Suppl):190S-194S
references: 15541666
references: Spine (Phila Pa 1976). 2011 Mar 1;36(5):393-8
references: 21325933
references: Orthopade. 2002 Apr;31(4):397-401
references: 12056282
references: Spine (Phila Pa 1976). 2008 Jul 15;33(16):1739-43
references: 18628706
references: Spine J. 2010 Oct;10 (10 ):896-9
references: 20615759
references: Eur Spine J. 2004 Oct;13(6):524-9
references: 15048563
references: Neurosurgery. 2007 Jan;60(1 Supp1 1):S118-29
references: 17204872
references: J Spinal Disord. 1992 Dec;5(4):464-75
references: 1490045
references: Spine J. 2012 Jul;12 (7):577-84
references: 22921806
references: Spine J. 2006 Nov-Dec;6(6):667-72
references: 17088197
references: Spine (Phila Pa 1976). 1992 Oct;17 (10 Suppl):S442-6
references: 1440041
references: Spine (Phila Pa 1976). 2010 Mar 15;35(6):704-8
references: 20195212
references: Spine (Phila Pa 1976). 1997 May 1;22(9):977-82
references: 9152447
references: J Neurosurg. 1991 Feb;74(2):190-8
references: 1988587
references: J Neurosurg Spine. 2009 Jul;11(1):28-33
references: 19569937
references: Spine (Phila Pa 1976). 2000 Apr 15;25(8):962-9
references: 10767809
references: Spine J. 2008 Jul-Aug;8(4):656-60
references: 17938004
references: J Neurosurg Spine. 2008 Apr;8(4):327-34
references: 18377317
references: Eur Spine J. 2000 Feb;9(1):61-6
references: 10766079
references: World Neurosurg. 2010 Feb;73(2):112-8; discussion e15
references: 20860937
references: J Neurosurg Spine. 2008 Nov;9(5):450-3
references: 18976176
references: J Spinal Disord. 1997 Oct;10(5):431-5
references: 9355061
references: Spine (Phila Pa 1976). 2001 Nov 15;26(22):2427-31
references: 11707704
references: J Spinal Disord Tech. 2004 Apr;17(2):158-62
references: 15260101
references: Spine J. 2006 Sep-Oct;6(5):603
references: 16934735
references: Spine (Phila Pa 1976). 1992 May;17(5):480-90
references: 1621145
references: Neurosurgery. 2011 Jun;68(6):1491-9; discussion 1499
references: 21346648
references: Spine (Phila Pa 1976). 2008 Oct 15;33(22):2415-21
references: 18923316
references: Spine (Phila Pa 1976). 1995 Nov 15;20(22):2442-8
references: 8578396
references: Z Orthop Ihre Grenzgeb. 1994 Jan-Feb;132(1):82-6
references: 8140781
references: Behav Res Methods. 2007 May;39(2):175-91
references: 17695343
references: Spine (Phila Pa 1976). 1996 Feb 15;21(4):462-8
references: 8658250
references: PLoS One. 2012;7(4):e35032
references: 22558112
references: Global Spine J. 2012 Mar;2(1):39-46
references: 24353945