The dual growing-rod technique involves implantation of a set of two rods and two anchor groups (upper and lower foundations) to exert frequent distractions to allow for spinal growth.
Step 1: (Initial Surgery): Positioning
Pay special attention to the effect of positioning on sagittal alignment.
Step 2: (Initial Surgery): Neuromonitoring
Use multimodality intraoperative neuromonitoring, including SSEPs, MEPs, EMG, and H-Reflexes.
Step 3: (Initial Surgery): Exposure
Avoid broad exposure of uninstrumented levels to prevent the risk of spontaneous fusion.
Step 4: (Initial Surgery): Preparation of Foundations
The foundation is an assembly of at least four anchors at two or three vertebrae along with one or two rods.
Step 5: (Initial Surgery): Choosing the Anchors
Use hooks or pedicle screws for the proximal foundation and use bilateral pedicle screws (a four-anchor construct) for the distal foundation.
Step 6: (Initial Surgery): Rod Contouring and Rod Assembly
Cut two 4.5-mm rods and contour them to the appropriate sagittal and coronal alignment, being careful not to overcorrect in the sagittal and coronal planes.
Step 7 (Initial Surgery): Tandem Connector Attachment
Place a tandem connector at the thoracolumbar junction to allow for future lengthening.
Step 8 (Initial Surgery): Final Implant Assembly
Pass the preassembled rods and tandem connector from caudad to cephalad beneath the fascia, securing them to the foundation and performing the first lengthening.
Step 9 (Initial Surgery): Wound Closure
Gentle handling of the skin and associated deeper tissues is essential to avoid complications.
Steps 1 and 2 (Lengthening): Positioning and Neuromonitoring
These are the same as those for the initial surgery.
Step 3 (Lengthening): Exposure
Make one incision between the two connectors on or in line with the original incision.
Step 4 (Lengthening): Lengthening Inside Versus Outside the Tandem Connector
Lengthening can be performed inside or outside the tandem connector.
Step 5 (Lengthening): Closure
See Step 9 for the initial surgery.
The quantity and quality of research on growth-sparing techniques for early-onset scoliosis have increased substantially in the past three years.
What to Watch For
Pitfalls & Challenges