General Editor: Luiz Vialle

Authors: Jean Ouellet

Spondylolisthesis Type 1

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1 Comment on approach top

Fluoroscopy is used to confirm the correct level of L5 and S1.


A midline skin incision is performed with the patient in prone position to access the L5-S1 joint.

The subperiosteal dissection is taken down onto the lamina of L5 exposing the L5-S1 joint

Care must be taken not to violate neither the L5-S1 joint nor the L4-L5 joint.

Dissection is carried laterally onto the transverse process of L5.

2 Instrumentation top


Pedicle screw insertion

Pedicle screws are inserted bilaterally into L5 taking care not to breach the L4-L5 facet.


Hook placement

A small notch is created on the inferior aspect of the L5 lamina in preparation for a sublaminar hook.

3 Decortication top


Using a high speed burr the defect in the pars articularis must be decorticated and the pseudoarthrosis excised down to bleeding bone.


Decortication is also taken to the transverse process of L5 along the lamina of L5.

4 Bone grafting top


A separate incision is made over the posterior superior iliac crest.


Muscle attached to the outer iliac crest is reflected in a blunt fashion exposing the outer iliac crest.


Using an osteotome or a gouge, corticocancellous strips are harvested in 4-5 cm length and 1 cm wide.


Smaller cancellous bone graft is also harvested from the iliac crest.


Bone graft must be impacted into the pars defect as well as the cortico cancellous strips are laid across the lamina and transverse process.

5 Rod insertion top


Bilaterally, laminar hooks are inserted.

Short rods are connected to the laminar hooks and pedicle screws and compression is applied to close the pars defect.

v1.0 2016-12-01