title: Biomechanical effects of a unilateral approach to minimally invasive lumbar decompression.
abstract: Minimally invasive (MI) lumbar decompression became a common approach to treat lumbar stenosis. This approach may potentially mitigate postoperative increases in segmental motion. The goal of this study was to evaluate modifications to segmental motion in the lumbar spine following a MI unilateral approach as compared to traditional facet-sparing and non-facet sparing decompressions. Six human lumbar cadaveric specimens were used. Each specimen was tested in flexion-extension 0 N and 400 N of follower preload), axial rotation, and lateral bending. Each testing condition was evaluated following three separate interventions at L4-L5: 1) Minimally invasive decompression, 2) Facet-sparing, bilateral decompression, and 3) Bilateral decompression with a wide facetectomy. Range of motion following each testing condition was compared to intact specimens. Both MI and traditional decompression procedures create significant increases in ROM in all modes of loading. However, when compared to the MI approach, traditional decompression produces significantly larger increase in ROM in flexion-extension (p<0.005) and axial rotation (p<0.05). It additionally creates increased ROM with lateral bending on the approach side (p<0.05). Lateral bending on the non-approach side is not significantly changed. Lastly, wide medial facet removal (40% to 50%) causes significant hypermobility, especially in axial rotation. While both MI and traditional lumbar decompressions may increase post-operative ROM in all conditions, a MI approach causes significantly smaller increase in ROM. With an MI approach, increased movement with lateral bending is only toward the approach side. Further, non-facet sparing decompression is further destabilizing in all loading modes.
authors.affiliation: Northwestern Feinberg School of Medicine, Department of Neurological Surgery, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Smith
authors.affiliation: Loyola University Stritch School of Medicine, Department of Orthopaedic Surgery, Maywood, Illinois, United States of America; Edward Hines Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Georgios A
authors.initials: GA
authors.lastname: Vastardis
authors.affiliation: Loyola University Stritch School of Medicine, Department of Orthopaedic Surgery, Maywood, Illinois, United States of America; Edward Hines Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Gerard
authors.initials: G
authors.lastname: Carandang
authors.affiliation: Loyola University Stritch School of Medicine, Department of Orthopaedic Surgery, Maywood, Illinois, United States of America; Edward Hines Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Havey
authors.affiliation: Loyola University Stritch School of Medicine, Department of Orthopaedic Surgery, Maywood, Illinois, United States of America; Edward Hines Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Sean
authors.initials: S
authors.lastname: Hannon
authors.affiliation: Northwestern Feinberg School of Medicine, Department of Neurological Surgery, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Nader
authors.initials: N
authors.lastname: Dahdaleh
authors.affiliation: Loyola University Stritch School of Medicine, Department of Orthopaedic Surgery, Maywood, Illinois, United States of America; Edward Hines Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Leonard I
authors.initials: LI
authors.lastname: Voronov
authors.affiliation: Northwestern Feinberg School of Medicine, Department of Neurological Surgery, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Fessler
authors.affiliation: Loyola University Stritch School of Medicine, Department of Orthopaedic Surgery, Maywood, Illinois, United States of America; Edward Hines Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Avinash G
authors.initials: AG
authors.lastname: Patwardhan
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular