Safety of sublaminar bands in surgical correction of adolescent idiopathic scoliosis Anton Borgers Lieven Moke Thibault Dewilde Pierre Moens U.Z. Leuven Belgium ISOC 2014 MEXICO

LEUVEN MEXICO

Introduction The aim of scoliosis fusion surgery is to stop curve progression and apply three-dimensional correction in order to restore trunk height and to achieve a balanced spine in both the coronal and sagittal plane

To this day hybrid constructs, using sublaminar devices, hooks and screws, as well as all-screw constructs are used in surgery of adolescent idiopathic scoliosis.

However some pedicle are not « screwable » This pedicule is thinner than the smallest screw of my tool box.

There has been controversy about the safety of passing steel wires under the lamina into the spinal canal

The goal of the present study is to assess the safety of sublaminar polyester bands in the instrumentation for adolescent idiopathic scoliosis.

Technical aspects Hybrid instrumentation Hooks Pedicle screws Universal Clamps

Universal Clamp

Intraoperative neuromonitoring Motor evoked potential-monitoring (MEP) Somatosensory evoked potential-monitoring (SSEP)

Patients 71 consecutive patients with adolescent idiopathic scoliosis (07/2008- 08/2012) 56 female patients and 15 male patients Mean age at time of surgery was 16.7 years Mean follow-up was 17.5 months

Lenke type

Mean number of levels fused: 11.9 +/- 1.4 Anterior release: 6 cases Mean number Universal Clamps: 5.9 (range 2 – 9)

Results Mean preoperative Cobb angle of the major curve was 60 +/-19 °. Mean postoperative Cobb angle was 23 +/-13°.

MEP, SSEP’S Intraoperative neuromonitoring changes were recorded in 8 of 71 patients

Two patients developed a transient neurologic deficit after surgery Only one patients with a postoperative neurologic deficit had intraoperative monitoring changes

We analyzed the recorded data for the moment of the monitoring changes and the surgical action performed at that time

Neuromonitoring changes

Neurologic deficits A first patient had decreased MEP-signals in the left lower limb during the procedure, SSEP’s remained variable within normal range After the procedure the patient had a paresis of the left leg (2/5). At day 3 the motor deficit in the left leg had partially recovered (4/5).

The second patient noted mild hypoesthesia of both thighs postoperative. She had no intraoperative monitoring changes.

The two patients recovered without sequelae

We did not found neuromonitoring changes during insertion or passage of the Universal clamps in this study

To be honest Some weeks ago we have had one neuromonitoring change when passing the band in a very lordotic thoracic spine The patient had a paresis of the left leg which recovered after some days but had still sensible toubles when going home, to be followed

At the EPOS 2014 the group of Marseille presented a similar study about more than 200 patients, with 3 cases of NMC, when passing the band The sagittal plan and the way of bending the band before insertion were the reasons of the changes

Conclusion We think that passing polyester bands like the Universal Clamp under the lamina remains a safe technique in the surgery of adolescent idiopathic scoliosis

Thank you for your attention and greetings from Belgium