title: No correlation between slip reduction in low-grade spondylolisthesis or change in neuroforaminal morphology and clinical outcome.
abstract: BACKGROUND
  In instrumented posterolateral fusion reduction of a spondylolisthesis is appealing on theoretical grounds since this may lead to indirect decompression of the entrapped nerve roots. However, there is no consensus in the literature whether a beneficial effect of reduction on outcome can be expected. The objective of the current study was to evaluate whether a correlation between the extent of listhesis reduction and clinical improvement could be established.
  
  
  METHODS
  From two ongoing prospective studies 72 patients with a single-level instrumented posterolateral lumbar fusion for low-grade spondylolisthesis (isthmic/degenerative 51/21) were evaluated. Radiographs and clinical outcome scores were available at baseline, 6 weeks and 1 year after surgery. Changes in neuroforaminal morphology were measured on calibrated radiographs. These changes in radiographic parameters were correlated to clinical outcome (Visual Analogue Score (VAS) leg pain, Oswestry Disability Index (ODI)). Fusion status was assessed on Computed Tomography-scan at one year.
  
  
  RESULTS
  A mean spondylolisthesis of 25 percent was reduced to 15 percent at 6 weeks with some loss of reduction to 17 percent at one year. The VAS and ODI significantly improved at both time intervals after surgery (p < 0.001). No significant correlations could be established between the extent of slip reduction and improvement in VAS or ODI (Pearson's correlation -0.2 and 0.07 respectively at one year); this also accounted for the other radiographic parameters. A fusion rate of 64 percent was seen on CT-scan.
  
  
  CONCLUSIONS
  Clinical outcome was not related to the obtained radiographic reduction of the slipped vertebra in patients with a lumbar fusion for low grade spondylolisthesis. Loss of reduction or non-union on CT-scans had no effect on the clinical outcome. Reduction of a low-grade spondylolisthesis in spinal fusion is appealing, however, there is no evidence that it positively affects clinical outcome on the short term.
  
  
  BACKGROUND
  ISRCTN43648350.
authors: H S
authors: HS
authors: Hagenmaier
authors: Diyar
authors: D
authors: Delawi
authors: Nico
authors: N
authors: Verschoor
authors: F
authors: F
authors: Oner
authors: Job L C
authors: JL
authors: van Susante
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D011446:Prospective Studies; D011859:Radiography; D016037:Single-Blind Method; D013123:Spinal Fusion / Q000379:methods / Q000639:trends*; D013168:Spondylolisthesis / Q000000981:diagnostic imaging* / Q000601:surgery*; D016896:Treatment Outcome
references: Spine (Phila Pa 1976). 1997 Dec 15;22(24):2807-12
references: 9431616
references: Spine (Phila Pa 1976). 2009 Jan 15;34(2):199-205
references: 19139672
references: Acta Orthop Belg. 2005 Feb;71(1):83-7
references: 15792212
references: Spine (Phila Pa 1976). 2011 May 15;36(11):E705-11
references: 21358576
references: Spine (Phila Pa 1976). 2000 Jul 1;25(13):1711-5
references: 10870148
references: J Hand Surg Am. 2007 May-Jun;32(5):647-50
references: 17482003
references: Spine J. 2005 Jan-Feb;5(1):36-44
references: 15653083
references: Spine (Phila Pa 1976). 2010 May 20;35(12):1185-91
references: 20445470
references: Eur Spine J. 2002 Oct;11(5):428-33
references: 12384749
references: J Bone Joint Surg Am. 1991 Jul;73(6):802-8
references: 2071615
references: Spine (Phila Pa 1976). 2005 Oct 1;30(19):E579-84
references: 16205332
references: Eur Spine J. 2006 Apr;15(4):391-402
references: 16217665
references: Eur Spine J. 2009 Oct;18(10):1494-503
references: 19562386
references: J Neurosurg Spine. 2011 Apr;14(4):488-96
references: 21314280
references: Scoliosis. 2011 Jul 28;6(1):14
references: 21797995
references: J Neurosurg. 2003 Sep;99(2 Suppl):143-50
references: 12956455
references: Spine (Phila Pa 1976). 2006 Jan 15;31(2):161-9; discussion 170
references: 16418634
references: Int Orthop. 2009 Oct;33(5):1335-40
references: 18679680
references: J Spinal Disord Tech. 2009 Jul;22(5):321-7
references: 19525786
references: Surg Neurol. 2005 Oct;64(4):303-8; discussion 308
references: 16181997
references: Physiotherapy. 1980 Aug;66(8):271-3
references: 6450426
references: Int Orthop. 2008 Oct;32(5):663-9
references: 17492449
references: J Bone Joint Surg Br. 2008 Dec;90(12):1617-22
references: 19043134
references: Spine J. 2006 Nov-Dec;6(6):606-14
references: 17088191
references: J Neurosurg. 2003 Sep;99(2 Suppl):151-6
references: 12956456
references: J Spinal Disord Tech. 2008 Oct;21(7):477-83
references: 18836358
references: Spine (Phila Pa 1976). 2005 Mar 15;30(6 Suppl):S97-101
references: 15767893
references: J Spinal Disord. 2001 Dec;14(6):522-32
references: 11723405
references: Kobe J Med Sci. 2006;52(6):151-69
references: 17329954
references: Lancet. 1974 Nov 9;2(7889):1127-31
references: 4139420
references: Spine J. 2012 Oct;12(10):877-80
references: 23199819
references: Spine (Phila Pa 1976). 2004 Jan 15;29(2):173-4
references: 14722410
references: Spine (Phila Pa 1976). 2006 Mar 1;31(5):583-90; discussion 591-2
references: 16508556