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A novel "four-rod technique" for lumbo-pelvic reconstruction: theory and technical considerations.
Spine (Phila Pa 1976). 2006 May 20; 31(12):1395-401.S

Abstract

STUDY DESIGN

Surgical technique with case example.

OBJECTIVE

To report on a novel technique that allows for the placement of 4 separate longitudinal rods across the lumbo-pelvic junction.

SUMMARY OF BACKGROUND DATA

Despite advances in surgical techniques and instrumentation, lumbo-pelvic fixation remains a significant challenge. Fusions to the pelvis create long lever arms and generate high forces across the lumbosacral junction, resulting in high rates of screw pullout and implant fracture. In the attempt to achieve better bony fixation, techniques described include the use of bone cement, hydroxyapatite, and expandable screws. Although this process has decreased the incidence of screw pullout, it has not addressed the problem of rod fracture at the lumbo-pelvic junction.

METHOD

There are 4 separate longitudinal rods placed across the lumbo-pelvic junction that couples proximal lumbar screw anchors to 4 separate pelvic fixation points. Proximal lumbar fixation anchors are based on alternating Roy-Camille "straight ahead" screws and Magerl "lateral to medial converging" pedicle screws. There are 4 distal pelvic fixation anchors used based on 1 pair of Galveston-like screws and 1 pair of proximal iliac wing screws.

RESULTS

Early results of both ex vivo and in vivo reconstruction show that careful insertion of the lumbar and pelvic screws allows for divergent placement of the pedicle screw heads in a manner that 2 longitudinal rods can be placed per side, resulting in a total of 4 longitudinal rods across the lumbo-pelvic junction. Selection of cross-links in various combinations allows for additional axial and torsional stability, depending on the desired reconstruction.

CONCLUSION

Longer follow-up is necessary, and biomechanical and finite element studies are needed to show long-term efficacy of this technique, however, early results indicate that such a construct is feasible. Furthermore, depending on the general medical condition of the patient, immediate postoperative weight bearing is possible and reasonable.

Authors+Show Affiliations

Department of Orthopedic Surgery, University of Virginia, Charlottesville, VA, USA. fhs2g@virginia.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Case Reports
Journal Article

Language

eng

PubMed ID

16721307

Citation

Shen, Francis H., et al. "A Novel "four-rod Technique" for Lumbo-pelvic Reconstruction: Theory and Technical Considerations." Spine, vol. 31, no. 12, 2006, pp. 1395-401.
Shen FH, Harper M, Foster WC, et al. A novel "four-rod technique" for lumbo-pelvic reconstruction: theory and technical considerations. Spine. 2006;31(12):1395-401.
Shen, F. H., Harper, M., Foster, W. C., Marks, I., & Arlet, V. (2006). A novel "four-rod technique" for lumbo-pelvic reconstruction: theory and technical considerations. Spine, 31(12), 1395-401.
Shen FH, et al. A Novel "four-rod Technique" for Lumbo-pelvic Reconstruction: Theory and Technical Considerations. Spine. 2006 May 20;31(12):1395-401. PubMed PMID: 16721307.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A novel "four-rod technique" for lumbo-pelvic reconstruction: theory and technical considerations. AU - Shen,Francis H, AU - Harper,Mark, AU - Foster,William C, AU - Marks,Ian, AU - Arlet,Vincent, PY - 2006/5/25/pubmed PY - 2006/7/6/medline PY - 2006/5/25/entrez SP - 1395 EP - 401 JF - Spine JO - Spine VL - 31 IS - 12 N2 - STUDY DESIGN: Surgical technique with case example. OBJECTIVE: To report on a novel technique that allows for the placement of 4 separate longitudinal rods across the lumbo-pelvic junction. SUMMARY OF BACKGROUND DATA: Despite advances in surgical techniques and instrumentation, lumbo-pelvic fixation remains a significant challenge. Fusions to the pelvis create long lever arms and generate high forces across the lumbosacral junction, resulting in high rates of screw pullout and implant fracture. In the attempt to achieve better bony fixation, techniques described include the use of bone cement, hydroxyapatite, and expandable screws. Although this process has decreased the incidence of screw pullout, it has not addressed the problem of rod fracture at the lumbo-pelvic junction. METHOD: There are 4 separate longitudinal rods placed across the lumbo-pelvic junction that couples proximal lumbar screw anchors to 4 separate pelvic fixation points. Proximal lumbar fixation anchors are based on alternating Roy-Camille "straight ahead" screws and Magerl "lateral to medial converging" pedicle screws. There are 4 distal pelvic fixation anchors used based on 1 pair of Galveston-like screws and 1 pair of proximal iliac wing screws. RESULTS: Early results of both ex vivo and in vivo reconstruction show that careful insertion of the lumbar and pelvic screws allows for divergent placement of the pedicle screw heads in a manner that 2 longitudinal rods can be placed per side, resulting in a total of 4 longitudinal rods across the lumbo-pelvic junction. Selection of cross-links in various combinations allows for additional axial and torsional stability, depending on the desired reconstruction. CONCLUSION: Longer follow-up is necessary, and biomechanical and finite element studies are needed to show long-term efficacy of this technique, however, early results indicate that such a construct is feasible. Furthermore, depending on the general medical condition of the patient, immediate postoperative weight bearing is possible and reasonable. SN - 1528-1159 UR - https://www.unboundmedicine.com/medline/citation/16721307/A_novel_"four_rod_technique"_for_lumbo_pelvic_reconstruction:_theory_and_technical_considerations_ L2 - http://dx.doi.org/10.1097/01.brs.0000219527.64180.95 DB - PRIME DP - Unbound Medicine ER -