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Biomechanical testing of a novel four-rod technique for lumbo-pelvic reconstruction.
Spine (Phila Pa 1976). 2008 Jun 01; 33(13):E400-6.S

Abstract

STUDY DESIGN

A biomechanical testing protocol was used to study different lumbo-pelvic fixation techniques in a human cadaveric lumbar spine model.

OBJECTIVE

To compare the in vitro biomechanics of a novel four-rod lumbo-pelvic reconstruction technique with and with out cross-links, to that of a conventional cross-linked two-rod technique.

SUMMARY OF BACKGROUND DATA

Numerous lumbo-pelvic reconstruction methods based on the Galveston two-rod technique have been proposed for cases involving total sacrectomy. Recently a technique that proposes novel use of 4 supporting longitudinal rods across the lumbo-pelvic junction has been reported. No comparative in vitro biomechanical testing has been previously done to evaluate these different reconstruction methods.

METHODS

Five spines were evaluated in flexion, extension, left-right lateral bending and left-right axial rotation in a human total sacrectomy model. The model was comprised of cadaveric lumbar spines (L1-L5) with custom fabricated polyethylene blocks used to simulate pelvic fixation. Three conditions were evaluated: Linked Four-Rod, Linked Two-Rod, and Four-Rod (no cross-links). Flexibility and motion data were compared using a one-way repeated measures analysis of variance and SNK tests.

RESULTS

The Linked Four-Rod and Four-Rod conditions significantly decreased flexibility and reduced L5-Pelvic motion over the Linked Two-Rod construct in flexion and extension. The Linked Four-Rod condition significantly decreased flexibility in left-right axial rotation compared with the Four-Rod and Linked Two-Rod conditions. No significant differences occurred in relative lateral movement between left and right pelvic polyethylene blocks.

CONCLUSION

The four-rod technique improved fixation stability over the conventional linked two-rod technique in flexion and extension, and when cross-linked, in left-right axial rotation. The four-rod technique also significantly reduced L5-Pelvic junction movement in flexionand extension, which may have implications for bony fusion. The use of cross-links is recommended.

Authors+Show Affiliations

Department of Biomedical Engineering and Imaging, University of Tennessee Health Science Center, Memphis, TN 38163, USA. bkelly@utmem.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18520925

Citation

Kelly, Brian P., et al. "Biomechanical Testing of a Novel Four-rod Technique for Lumbo-pelvic Reconstruction." Spine, vol. 33, no. 13, 2008, pp. E400-6.
Kelly BP, Shen FH, Schwab JS, et al. Biomechanical testing of a novel four-rod technique for lumbo-pelvic reconstruction. Spine. 2008;33(13):E400-6.
Kelly, B. P., Shen, F. H., Schwab, J. S., Arlet, V., & Diangelo, D. J. (2008). Biomechanical testing of a novel four-rod technique for lumbo-pelvic reconstruction. Spine, 33(13), E400-6. https://doi.org/10.1097/BRS.0b013e31817615c5
Kelly BP, et al. Biomechanical Testing of a Novel Four-rod Technique for Lumbo-pelvic Reconstruction. Spine. 2008 Jun 1;33(13):E400-6. PubMed PMID: 18520925.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Biomechanical testing of a novel four-rod technique for lumbo-pelvic reconstruction. AU - Kelly,Brian P, AU - Shen,Francis H, AU - Schwab,John S, AU - Arlet,Vincent, AU - Diangelo,Denis J, PY - 2008/6/4/pubmed PY - 2008/7/11/medline PY - 2008/6/4/entrez SP - E400 EP - 6 JF - Spine JO - Spine VL - 33 IS - 13 N2 - STUDY DESIGN: A biomechanical testing protocol was used to study different lumbo-pelvic fixation techniques in a human cadaveric lumbar spine model. OBJECTIVE: To compare the in vitro biomechanics of a novel four-rod lumbo-pelvic reconstruction technique with and with out cross-links, to that of a conventional cross-linked two-rod technique. SUMMARY OF BACKGROUND DATA: Numerous lumbo-pelvic reconstruction methods based on the Galveston two-rod technique have been proposed for cases involving total sacrectomy. Recently a technique that proposes novel use of 4 supporting longitudinal rods across the lumbo-pelvic junction has been reported. No comparative in vitro biomechanical testing has been previously done to evaluate these different reconstruction methods. METHODS: Five spines were evaluated in flexion, extension, left-right lateral bending and left-right axial rotation in a human total sacrectomy model. The model was comprised of cadaveric lumbar spines (L1-L5) with custom fabricated polyethylene blocks used to simulate pelvic fixation. Three conditions were evaluated: Linked Four-Rod, Linked Two-Rod, and Four-Rod (no cross-links). Flexibility and motion data were compared using a one-way repeated measures analysis of variance and SNK tests. RESULTS: The Linked Four-Rod and Four-Rod conditions significantly decreased flexibility and reduced L5-Pelvic motion over the Linked Two-Rod construct in flexion and extension. The Linked Four-Rod condition significantly decreased flexibility in left-right axial rotation compared with the Four-Rod and Linked Two-Rod conditions. No significant differences occurred in relative lateral movement between left and right pelvic polyethylene blocks. CONCLUSION: The four-rod technique improved fixation stability over the conventional linked two-rod technique in flexion and extension, and when cross-linked, in left-right axial rotation. The four-rod technique also significantly reduced L5-Pelvic junction movement in flexionand extension, which may have implications for bony fusion. The use of cross-links is recommended. SN - 1528-1159 UR - https://www.unboundmedicine.com/medline/citation/18520925/Biomechanical_testing_of_a_novel_four_rod_technique_for_lumbo_pelvic_reconstruction_ L2 - http://dx.doi.org/10.1097/BRS.0b013e31817615c5 DB - PRIME DP - Unbound Medicine ER -