Format

Send to

Choose Destination
Eur Spine J. 2013 Dec;22(12):2731-9. doi: 10.1007/s00586-013-3003-2. Epub 2013 Sep 17.

Relation between radiological assessment and biomechanical stability of lumbar interbody fusion in a large animal model.

Author information

1
Department of Orthopaedic Surgery, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands, rjkroeze@yahoo.com.

Abstract

PURPOSE:

To relate the progress of vertebral segmental stability after interbody fusion surgery with radiological assessment of spinal fusion.

METHODS:

Twenty goats received double-level interbody fusion and were followed for a period of 3, 6 and 12 months. After killing, interbody fusion was assessed radiographically by two independent observers. Subsequently, the lumbar spines were subjected to four-point bending and rotational deformation, assessed with an optoelectronic 3D movement registration system. In addition, four caprine lumbar spines were analysed in both the native situation and after the insertion of a cage device, as to mimic the direct post-surgical situation. The range of motion (ROM) in flexion/extension, lateral bending and axial rotation was analysed ex vivo using a multi-segment testing system.

RESULTS:

Significant reduction in ROM in the operated segments was already achieved with moderate bone ingrowth in flexion/extension (71 % reduction in ROM) and with only limited bone ingrowth in lateral bending (71 % reduction in ROM) compared to the post-surgical situation. The presence of a sentinel sign always resulted in a stable vertebral segment in both flexion/extension and lateral bending. For axial rotation, the ROM was already limited in both native and cage inserted situations, resulting in non-significant differences for all radiographic scores.

DISCUSSION:

In vivo vertebral segment stability, defined as a significant reduction in ROM, is achieved in an early stage of spinal fusion, well before a radiological bony fusion between the vertebrae can be observed. Therefore, plain radiography underestimates vertebral segment stability.

PMID:
24043338
PMCID:
PMC3843781
DOI:
10.1007/s00586-013-3003-2
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Springer Icon for PubMed Central
Loading ...
Support Center