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Free-hand placement of iliac screws for spinopelvic fixation based on anatomical landmarks: technical note.

Fridley J, Fahim D, Navarro J, Wolinsky JP, Omeis I - Int J Spine Surg (2014)

Bottom Line: We have successfully used this technique for the placement 20 iliac screws based on anatomic landmarks in 10 consecutive patients.Based on our limited experience to date, free-hand placement of iliac screws is both easy to perform and safe for the patient.Further study and validation using this technique is warranted.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, TX.

ABSTRACT

Background: The placement of iliac screws is a biomechanically sound method for the stabilization of long multi-segment lumbar constructs. Traditional techniques for the placement of iliac screws often involve either substantial iliac muscle dissection for visualization of screw trajectory based on bony landmarks, or alternatively the use of intra-operative imaging to visualize these landmarks and guide screw placement. We describe an alternative free-hand method of iliac screw placement, one that needs neither significant muscle dissection nor intra-operative imaging.

Methods: We performed this technique in 10 consecutive patients. Patient demographics, spinal pathology, post-operative complications, and screw hardware characteristics are described.

Results: We have successfully used this technique for the placement 20 iliac screws based on anatomic landmarks in 10 consecutive patients. There were no cortical breeches of the ileum and no penetrations into the acetabulum on post-operative imaging. There were no instances of hardware failure. Two patients developed deep vein thromboses after surgery, 1 had a pulmonary embolism.

Conclusions: Based on our limited experience to date, free-hand placement of iliac screws is both easy to perform and safe for the patient. Further study and validation using this technique is warranted.

No MeSH data available.


Related in: MedlinePlus

Illustration of the free-hand technique for iliac screw placement. Note that the probe shafts are parallel to the L5 lamina with both probes intersecting over the L5 spinous process. The screw entry point is adjacent to the PSIS.
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Figure 0001: Illustration of the free-hand technique for iliac screw placement. Note that the probe shafts are parallel to the L5 lamina with both probes intersecting over the L5 spinous process. The screw entry point is adjacent to the PSIS.

Mentions: To determine the trajectory for the iliac screws and create their tracts in the ilium, two gear-shift pedicle probes are angled such that their shafts are parallel to the L5 lamina, superior to inferior, with the tip of the probe pointing into the notch created in the ilium (Figure 1). The shafts of the two probes should intersect each other over the L5 spinous process making sure they are still parallel to the lamina. The trajectory that each probe takes after these steps are performed is the path that each iliac screw should take during placement, which approximates the trajectory from the PSIS to the AIIS (Figure 2). Screw length is determined based on pre-operative imaging and intra-operative probing. The screw travels above the dense cortical bone surrounding the superior aspect sciatic notch. In addition, if they are following the correct trajectory, the path of the probe will go over the L5-S1 facet joint. Each iliac screw is placed and seated such that there is no significant screw head prominence. Any connectors are attached, and then the remaining steps are undertaken for completion of the spinal construct.


Free-hand placement of iliac screws for spinopelvic fixation based on anatomical landmarks: technical note.

Fridley J, Fahim D, Navarro J, Wolinsky JP, Omeis I - Int J Spine Surg (2014)

Illustration of the free-hand technique for iliac screw placement. Note that the probe shafts are parallel to the L5 lamina with both probes intersecting over the L5 spinous process. The screw entry point is adjacent to the PSIS.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325501&req=5

Figure 0001: Illustration of the free-hand technique for iliac screw placement. Note that the probe shafts are parallel to the L5 lamina with both probes intersecting over the L5 spinous process. The screw entry point is adjacent to the PSIS.
Mentions: To determine the trajectory for the iliac screws and create their tracts in the ilium, two gear-shift pedicle probes are angled such that their shafts are parallel to the L5 lamina, superior to inferior, with the tip of the probe pointing into the notch created in the ilium (Figure 1). The shafts of the two probes should intersect each other over the L5 spinous process making sure they are still parallel to the lamina. The trajectory that each probe takes after these steps are performed is the path that each iliac screw should take during placement, which approximates the trajectory from the PSIS to the AIIS (Figure 2). Screw length is determined based on pre-operative imaging and intra-operative probing. The screw travels above the dense cortical bone surrounding the superior aspect sciatic notch. In addition, if they are following the correct trajectory, the path of the probe will go over the L5-S1 facet joint. Each iliac screw is placed and seated such that there is no significant screw head prominence. Any connectors are attached, and then the remaining steps are undertaken for completion of the spinal construct.

Bottom Line: We have successfully used this technique for the placement 20 iliac screws based on anatomic landmarks in 10 consecutive patients.Based on our limited experience to date, free-hand placement of iliac screws is both easy to perform and safe for the patient.Further study and validation using this technique is warranted.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, TX.

ABSTRACT

Background: The placement of iliac screws is a biomechanically sound method for the stabilization of long multi-segment lumbar constructs. Traditional techniques for the placement of iliac screws often involve either substantial iliac muscle dissection for visualization of screw trajectory based on bony landmarks, or alternatively the use of intra-operative imaging to visualize these landmarks and guide screw placement. We describe an alternative free-hand method of iliac screw placement, one that needs neither significant muscle dissection nor intra-operative imaging.

Methods: We performed this technique in 10 consecutive patients. Patient demographics, spinal pathology, post-operative complications, and screw hardware characteristics are described.

Results: We have successfully used this technique for the placement 20 iliac screws based on anatomic landmarks in 10 consecutive patients. There were no cortical breeches of the ileum and no penetrations into the acetabulum on post-operative imaging. There were no instances of hardware failure. Two patients developed deep vein thromboses after surgery, 1 had a pulmonary embolism.

Conclusions: Based on our limited experience to date, free-hand placement of iliac screws is both easy to perform and safe for the patient. Further study and validation using this technique is warranted.

No MeSH data available.


Related in: MedlinePlus