E-Case report

Minimally Invasive AIS SurgeryDr. Alejandro Peiró García

Pre OP

Clinical Case – Minimally Invasive AIS Surgery

Alejandro Peiró García , MD
Orthopaedic and Trauma surgeon
University Hospital Sant Joan de Déu
Barcelona, Spain

Patient Information

Adolescent Idiopathic Scoliosis (AIS) in a 16 years old female patient

  • Flexible AIS with main thoracic right curvature
  • Single curve with apex at T9

The challenge of the surgery will be to:

  • fuse a minimum number of vertebrae trying to avoid motion restriction
  • reduce the soft tissue damage in a traditionally aggressive surgery

Pre OP

EOS standing radiographs
frontal & sagittal views

Surgical Planning

Type: Lenke 2B (Modifier B)

Pre op Correction Objective
Cobb angle 50° <10°
Thoracic Kyphosis (TK) -5° >10°
Lumbar Lordosis (LL) 47.3° same

Surgical Planning

  • Skin incision
    • High thoracic (T3 -T4) percutaneously
    • Apex (T7 – T10) midline open
    • Bottom (T12 – L1) midline open
  • Access & facetectomies
  • CT screw navigation – Philips ClarifEye™
  • K-wires & pedicle markers positioning
  • T3 – L1 screw insertion – Neo Pedicle Screw System™
  • Neuromonitoring check
  • Rods insertion
  • Postero-medial translation technique for the correction of the coronal and sagittal planes
  • Final tightening

Intra OP

Skin incision according to plan

Access & facetectomies
  • Top –        None
  • Apex –     Schwab Grade 1 or 2*
  • Bottom – Schwab Grade 1 or 2*

* Schwab 1 = Partial facetectomy

Schwab 2 = Complete facetectomy

CT screw navigation – Philips ClarifEye™  used for the insertion of the 15 pedicle screws
Insertion of pedicle screws, Neo Pedicle Screw System™:
  • High thoracic (T3-T4) MIS => Polyaxial
  • Apex (T7 to T10) Midline open => Monoplanar
  • Bottom (L1-T12) Wiltse   => Polyaxial

Correction will be applied by the integrated reduction threads and spreading the correction forces over the whole construct. This is reinforced to the usage of monoplanar screws in the apex of the curve.

Neuromonitoring check

Rod insertion & Correction of the coronal and sagittal planes.
  1. Insertion of the CoCr rod in the concave side, set in the sagittal plane.
  2. Tightening of the polyaxial screws using the torque limiter at top & bottom, to create a bridge with 2 anchor points.
  3. Translation manœuvres from caudal to cranial with torque limiter to smoothly lift the spine up to the rod and derotate the apex using the capacity of the the monoplanar screws.
  4. Reinforce tightening without torque limiter
  5. Insertion of the bent CoCr rod in the convex side

The rod holder is a key instruments to allow for proper rodinsertion.

Post OP

Post OP results

After both sides have been tightened, the coronal alignment can be further restored by the use of the monoplanar screw guides to derotate the spine.

Pre op Post Op
Cobb angle 50° 9°
Thoracic Kyphosis (TK) -5° 12.5°
Lumbar Lordosis (LL) 47.3° 45.5°

Post OP Radiographs, standing sagittal & frontal

Published with the approval of
Dr. Alejandro Peiró García