Executive Editor: Peter Trafton

Authors: Rahul Banerjee, Peter Brink, Matej Cimerman, Tim Pohlemann, Matevz Tomazevic

Pelvic ring - Sacrum, Ilioiliac plate

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Glossary

1 Introduction top

Posterior fixation of displaced sacral fractures is frequently enhanced by the use of transiliac plate fixation. This is usually an adjunct to transiliac sacral screw fixation but some constructs can be used as stand-alone alternatives.


This form of fixation is especially advantageous in cases of large comminuted zones to bridge the comminuted zone.


Two basic types of plate utilization are possible:

  • Tension band as an adjunct to one or more transiliac sacral screws
  • Solitary bridging fixation which typically requires a stronger plate in combination with fixation through the plate to the sacrum

Plating variations

There are two commonly anatomic variations for plate placement:

  1. Plate between the interspinous zones of the ilium, either anterior or posterior to the paraspinal muscles.
  2. Submuscular at the level of S2 bridging to the innominate bones just cranial to the greater sciatic notch.

2 Reduction top

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The typical displacements are cranial and posterior together with sagittal plane rotation.


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Prior to starting the procedure fluoroscopic AP, inlet and outlet x-rays should be obtained to ensure adequate visualization.


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Two vertical contralateral incisions are made over the iliac crests which provide access for the fixation of the plate in both iliac wings.


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Preliminary fixation

The primary reduction maneuver typically involves the use of two pointed reduction forceps (Weber clamps).

These span from the spinous process to the lateral ilium and are used to obtain a reduction incrementally by alternating translation and clamping.


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Additional reduction techniques

Fix the anatomic reduction with pointed reduction forceps.

If needed, insert Schanz screws to both posterior iliac crests as a reduction aid for better rotational alignment.


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The AO distractor may be used as a distraction aid.

K-wires may be placed into the SI joints in order to determine the joint orientation.

3 Plate used as a tension band top

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After reduction and initial iliosacral screw placement, a tension band plate is added for additional stability.


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Remove the tip of the spinous process of (S2/S3) if it is in the way of the plate.

Use a small chisel if the approach with two vertical incisions is performed.


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Apply the contoured plate onto the fracture site by sliding it underneath the paraspinal muscles. The plate is turned 180° along its axis to facilitate insertion.


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The initial screws are inserted into the sciatic buttress and sequentially tightened to compress the plate against the ilia.


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The advantage of this anatomic location is the additional fixation provided by longer screws into the densest bone in the ilium.


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The ends of the plate are then contoured in situ and additional short screws, which may or may not cross the IS joint, are inserted into the innominate bone.

4 Alternative fixation technique top

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Achieve posterior fixation by applying a contoured 4.5 mm DC-plate.

Choose the plate long enough to reach from one iliac wing across the sacrum to the opposite ilium.

Use a short bending template to determine the correct shape of each side. Then bend the ends of the plate to fit.

The plate crosses the sacrum in the midline of the second and third sacral foramen.

When applied, the plate should reach over the posterior inferior spines providing space for fixation with at least two additional screws (3-4 screws if needed).


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Remove the tip of the spinous process of (S2/S3) if it is in the way of the plate.

Use a small chisel if the approach with two vertical incisions is performed.

 


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Apply the contoured plate onto the fracture site by sliding it underneath the paraspinal muscles. The plate is turned 180° along its axis to facilitate insertion.


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The plate will be attached to the ilia with screws inserted between the two iliac cortices.

Start fixing the plate to the uninjured (contralateral) side by using a 3.2 mm drill bit in the direction of the two iliac cortices. Stop drilling when you reach cortical resistance.

After measurement, insert a 4.5 mm screw. Screw length is typically 50-60 mm.

Repeat this on the injured side.

Tighten the screws sequentially before applying the second pair of screws.

 


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For the second screw on each side, which will cross the SI-joint into the sacrum, aim medially and cranially with the drill bit (outer half sacral ala).

Two 4.5 mm screws of correct length is inserted through each end of the plate.

Note

If applicable, apply additional screws into the “save zones” of the sacrum, to increase the stability of the whole “construction”.

 

5 Alternative plate and screw fixation top

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Transverse plating at the level of the posterior superior iliac spine can be made less prominent by creating a bony notch for seating the plate. Screw placement in this location usually is into the pedicle of S1 and between the tables of the ileum.

6 Additional stability top

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In case of a very comminuted fracture, the placement of two plates will give additional stability.

Make a trough in both iliac crests at the level of S1, deep enough so that the plate lies on the sacrum.

7 X-rays top

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After completion of internal fixation, confirm the final reduction and hardware position intraoperatively by AP, inlet and outlet radiographic imaging.

v1.0 2015-12-10