title: The effects of single-level instrumented lumbar laminectomy on adjacent spinal biomechanics.
abstract: Study Design Biomechanical study. Objective Posterior instrumentation is used to stabilize the spine after a lumbar laminectomy. However, the effects on the adjacent segmental stability are unknown. Therefore, we studied the range of motion (ROM) and stiffness of treated lumbar spinal segments and cranial segments after a laminectomy and after posterior instrumentation in flexion and extension (FE), lateral bending (LB), and axial rotation (AR). These outcomes might help to better understand adjacent segment disease (ASD), which is reported cranial to the level on which posterior instrumentation is applied. Methods We obtained 12 cadaveric human lumbar spines. Spines were axially loaded with 250 N for 1 hour. Thereafter, 10 consecutive load cycles (4 Nm) were applied in FE, LB, and AR. Subsequently, a laminectomy was performed either at L2 or at L4. Thereafter, load-deformation tests were repeated, after similar preloading. Finally, posterior instrumentation was added to the level treated with a laminectomy before testing was repeated. The ROM and stiffness of the treated, the cranial adjacent, and the control segments were calculated from the load-displacement data. Repeated-measures analyses of variance used the spinal level as the between-subject factor and a laminectomy or instrumentation as the within-subject factors. Results After the laminectomy, the ROM increased (+19.4%) and the stiffness decreased (-18.0%) in AR. The ROM in AR of the adjacent segments also increased (+11.0%). The ROM of treated segments after instrumentation decreased in FE (-74.3%), LB (-71.6%), and AR (-59.8%). In the adjacent segments after instrumentation, only the ROM in LB was changed (-12.9%). Conclusions The present findings do not substantiate a biomechanical pathway toward or explanation for ASD.
authors: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, Amsterdam, The Netherlands.
authors: Arno
authors: A
authors: Bisschop
authors: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, Amsterdam, The Netherlands.
authors: Roderick M
authors: RM
authors: Holewijn
authors: Faculty of Human Movement Sciences, Research Institute MOVE, VU University Amsterdam, Amsterdam, The Netherlands.
authors: Idsart
authors: I
authors: Kingma
authors: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, Amsterdam, The Netherlands.
authors: Agnita
authors: A
authors: Stadhouder
authors: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, Amsterdam, The Netherlands.
authors: Pieter-Paul A
authors: PP
authors: Vergroesen
authors: Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors: Albert J
authors: AJ
authors: van der Veen
authors: Faculty of Human Movement Sciences, Research Institute MOVE, VU University Amsterdam, Amsterdam, The Netherlands ; Department of Biomedical Engineering, King Abdulaziz University, Jeddah, Saudi Arabia.
authors: Jaap H
authors: JH
authors: van Dieën
authors: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, Amsterdam, The Netherlands.
authors: Barend J
authors: BJ
authors: van Royen
keywords: adjacent segment disease (ASD); biomechanics; human lumbar spine; instrumentation; single-level laminectomy
references: BMC Musculoskelet Disord. 2011 Feb 07;12:38
references: 21299900
references: Spine (Phila Pa 1976). 1984 Oct;9(7):725-33
references: 6505843
references: J Neurosurg. 2003 Sep;99(2 Suppl):214-20
references: 12956465
references: Spine (Phila Pa 1976). 2014 Jan 15;39(2):172-6
references: 24153168
references: N Engl J Med. 2004 Feb 12;350(7):722-6
references: 14960750
references: Spine (Phila Pa 1976). 2009 Dec 15;34(26):2858-64
references: 20010393
references: Eur Spine J. 1998;7(2):148-54
references: 9629939
references: J Neurosurg. 1996 Nov;85(5):793-802
references: 8893716
references: Arch Orthop Trauma Surg. 2010 Feb;130(2):285-92
references: 19936771
references: Spine (Phila Pa 1976). 2010 Jan 15;35(2):E35-42
references: 20081499
references: J Biomech. 2013 Jan 4;46(1):187-91
references: 23159163
references: BMC Musculoskelet Disord. 2011 Oct 18;12:239
references: 22008088
references: Spine J. 2013 Mar;13(3):342-51
references: 23420004
references: J Spinal Disord. 1992 Dec;5(4):383-9; discussion 397
references: 1490034
references: Spine (Phila Pa 1976). 1999 May 15;24(10):1003-9
references: 10332793
references: Clin Biomech (Bristol, Avon). 2014 Sep;29(8):912-7
references: 25028214
references: Spine (Phila Pa 1976). 2008 Dec 15;33(26):2868-73
references: 19092616
references: J Biomech. 2012 Jun 26;45(10):1753-8
references: 22648145
references: Clin Orthop Relat Res. 2001 Mar;(384):75-81
references: 11249182
references: Spine (Phila Pa 1976). 2013 Dec 15;38(26):2287-94
references: 24150428
references: Chin Med J (Engl). 2012 Nov;125(22):3942-6
references: 23158121
references: Spine (Phila Pa 1976). 2014 Mar 1;39(5):E339-45
references: 24365899
references: Arch Orthop Trauma Surg. 1980;97(4):257-62
references: 7458609
references: Eur Spine J. 2009 Aug;18(8):1175-86
references: 19337757
references: Eur Spine J. 2013 Aug;22(8):1785-93
references: 23460462
references: Spine (Phila Pa 1976). 2008 Mar 1;33(5):514-8
references: 18317196
references: J Spinal Disord Tech. 2003 Aug;16(4):418-23
references: 12902959
references: Spine J. 2013 Oct;13(10):1339-49
references: 23773433
references: J Spinal Disord. 1992 Dec;5(4):390-6; discussion 397
references: 1490035
references: Eur Spine J. 2012 Mar;21(3):530-6
references: 21863461