Safety of sublaminar bands in surgical correction of adolescent idiopathic

scoliosis

Anton BorgersLieven Moke Thibault DewildePierre Moens

U.Z. LeuvenBelgium

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.

This pedicule is thinner than the smallest screw of my tool box.

However some pedicle are not « screwable »

• 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

Type 1 Type 2 Type 3 Type 4 Type 5 Type 60

10

20

30

40

50

60

• 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