title: Single level lumbar laminectomy alters segmental biomechanical behavior without affecting adjacent segments.
abstract: BACKGROUND
  Degenerative lumbar spinal stenosis causes neurological symptoms due to neural compression. Lumbar laminectomy is a commonly used treatment for symptomatic degenerative spinal stenosis. However, it is unknown if and to what extent single level laminectomy affects the range of motion and stiffness of treated and adjacent segments. An increase in range of motion and a decrease in stiffness are possible predictors of post-operative spondylolisthesis or spinal failure.
  
  
  METHODS
  Twelve cadaveric human lumbar spines were obtained. After preloading, spines were tested in flexion-extension, lateral bending, and axial rotation. Subsequently, single level lumbar laminectomy analogous to clinical practice was performed at level lumbar 2 or 4. Thereafter, load-deformation tests were repeated. The range of motion and stiffness of treated and adjacent segments were calculated before and after laminectomy. Untreated segments were used as control group. Effects of laminectomy on stiffness and range of motion were tested, separately for treated, adjacent and control segments, using repeated measures analysis of variance.
  
  
  RESULTS
  Range of motion at the level of laminectomy increased significantly for flexion and extension (7.3%), lateral bending (7.5%), and axial rotation (12.2%). Range of motion of adjacent segments was only significantly affected in lateral bending (-7.7%). Stiffness was not affected by laminectomy.
  
  
  CONCLUSIONS
  The increase in range of motion of 7-12% does not seem to indicate the use of additional instrumentation to stabilize the lumbar spine. If instrumentation is still considered in a patient, its primary focus should be on re-stabilizing only the treated segment level.
authors.affiliation: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. Electronic address: a.bisschop@vumc.nl.
authors.forename: Arno
authors.initials: A
authors.lastname: Bisschop
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
authors.forename: Susanne J P M
authors.initials: SJ
authors.lastname: van Engelen
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
authors.forename: Idsart
authors.initials: I
authors.lastname: Kingma
authors.affiliation: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Roderick M
authors.initials: RM
authors.lastname: Holewijn
authors.affiliation: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Agnita
authors.initials: A
authors.lastname: Stadhouder
authors.affiliation: Department of Physics and Medical Technology, VU University Medical Center, The Netherlands.
authors.forename: Albert J
authors.initials: AJ
authors.lastname: van der Veen
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands; Department of Biomedical Engineering, King Abdulaziz University, Saudi Arabia.
authors.forename: Jaap H
authors.initials: JH
authors.lastname: van Dieën
authors.affiliation: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. Electronic address: bj.vanroyen@vumc.nl.
authors.forename: Barend J
authors.initials: BJ
authors.lastname: van Royen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008875:Middle Aged; D009068:Movement; D016059:Range of Motion, Articular; D012399:Rotation; D013123:Spinal Fusion / Q000295:instrumentation*; D013130:Spinal Stenosis; D013131:Spine / Q000601:surgery; D013168:Spondylolisthesis; D013314:Stress, Mechanical
keywords: Adjacent segment; Biomechanics; Human lumbar spine; Range of motion; Single level laminectomy; Stiffness