Abstract
INTRODUCTION: 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. RESULTS: 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: IndicationsContraindicationsPitfalls & Challenges.