Growth-guided instrumentation: Shilla procedure

The Shilla growth guidance (SGG) technique for early-onset scoliosis (EOS) was developed to allow for growth of a child's spine without requiring scheduled returns to the operating room for lengthenings. The center of the deformity (apex) is corrected in all planes (coronal, sagittal, and axial) with osteotomies, bilateral screw fixation, and corrective maneuvers. Dual rods are fixed to the corrected apex with fusion of the apical segments. Transmuscular sliding pedicle screws are placed above and below the apex without disrupting the periosteum; the Shilla screw cap (which tightens to the screw and not to the rod) then allows vertebral growth in a cephalad and caudad direction. Careful preoperative planning must be carried out, incorporating flexibility radiographs. The use of Ponte osteotomies typically allows for sufficient apical correction. In severe or very stiff curves, the Shilla technique can be used in conjunction with vertebral column resection, hemivertebra excision, or anterior release. The largest feasible rod diameter should be used to minimize rod fractures, and screws of maximum diameter and length used to minimize pullout. Navigation can be a valuable tool to aid in placing the transmuscular sliding screws by further minimizing periosteal dissection and safely maximizing screw length. The Shilla growth guidance technique offers a method of treatment for EOS allowing spinal growth while controlling the deformity, reducing repeated returns to surgery. The complication rate is acceptable and multiple diagnoses can safely be treated with the Shilla technique. Shilla has been favorably compared to dual traditional growing rods and to magnetically controlled growing rods. Patients are allowed to participate in most normal childhood activities.