Range of motion after thoracolumbar corpectomy: evaluation of analogous constructs with a novel low-profile anterior dual-rod system and a traditional dual-rod system.
An in vitro biomechanical study.



To compare the biomechanical stability of traditional and low-profile thorocolumbar anterior instrumentation after a corpectomy with cross-connectors. Dual-rod anterior thoracolumbar lateral plates (ATLP) have been used clinically to stabilize the thorocolumbar spine.



The stability of a low-profile dual-rod system (LP DRS) and a traditional dual-rod system (DRS) was compared using a calf spine model. Two groups of seven specimens were tested intact and then in the following order: (1) ATLP with two cross-connectors and spacer; (2) ATLP with one cross-connector and spacer; (3) ATLP with spacer. Data were normalized to intact (100 %) and statistical analysis was used to determine between-group significances.



Both constructs reduced motion compared to intact in flexion-extension and lateral bending. Axial rotation motion became unstable after the corpectomy and motion was greater than intact, even with two cross-connectors with both systems. Relative to their respective intact groups, LP DRS significantly reduced motion compared to analogous DRS in flexion-extension. The addition of cross-connectors reduced motion in all loading modes.



The LP DRS provides 7.5 mm of reduced height with similar biomechanical performance. The reduced height may be beneficiary by reduced irritation and impingement on adjacent structures.
Spine Unit, Department of Orthopaedic Surgery, Rigshospitalet, National University Hospital of Copenhagen, Skolevej 14, Gentofte, 2820, Copenhagen, Denmark.
Martin
M
Gehrchen
Apollo Hospital, 21 Greams Lane, Chennai, India.
Sajan K
SK
Hegde
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., 2560 General Armistead Ave, Audubon, PA, 19403, USA. mmoldavsky@globusmedical.com.
Mark
M
Moldavsky
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., 2560 General Armistead Ave, Audubon, PA, 19403, USA.
Suresh
S
Chinthukunta
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., 2560 General Armistead Ave, Audubon, PA, 19403, USA.
Manasa
M
Gudipally
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., 2560 General Armistead Ave, Audubon, PA, 19403, USA.
Brandon
B
Bucklen
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., 2560 General Armistead Ave, Audubon, PA, 19403, USA.
Kanaan
K
Salloum
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., 2560 General Armistead Ave, Audubon, PA, 19403, USA.
Saif
S
Khalil
D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D008159:Lumbar Vertebrae / Q000601:surgery*; D023421:Models, Animal; D019736:Prostheses and Implants; D016059:Range of Motion, Articular; D013904:Thoracic Vertebrae / Q000601:surgery*
Anterior lateral fixation; Biomechanics; Corpectomy; Cross-connectors; Low profile