BASIC PRINCIPLES IN THE CORRECTION OF SEVERE SCOLIOTIC DEFORMITIES USING PEDICLE SCREW FIXATION

ABSTRACT Objective: To determine the effectiveness of surgical treatment of patients with idiopathic scoliosis who have severe spinal deformity, using either all pedicle screw or hybrid constructs. Methods: A retrospective analysis of the results of treatment of 34 patients aged 15 to 27 years with severe scoliosis, operated on using pedicle screws. A comparison group consisted of 22 patients who were operated on using hybrid constructs. Patients from both groups were compared according to the following parameters: pre/postoperative Cobb angle, mobility according to the traction test, global sagittal/frontal balance, apical vertebral rotation, operative time, intraoperative blood loss, number of instrumented vertebrae, and loss of correction within 24 months. Results: In group A (pedicle screw fixation) compared to group B (hybrid spinal fixation), patients had better results in the following parameters: postoperative correction was 48% and 41%, apical vertebral rotation decreased from 78° to 55° (30%) and from 74° to 59° (21%), correction of global frontal/sagittal balance from 39/25 mm to 14/12 mm (64%/52%) and 35/26 mm to 16/15 mm (55%/43%) between treatment groups, respectively. These results suggest a better trunk balance and greater postoperative correction in patients submitted to the all pedicle screw fixation. Smaller values were found for loss of correction of the major curve, and there was a slight increase in thoracic kyphosis in the postoperative period (24 months) 3.8%/4.3% in group A vs. 6.2%/7.5% in group B, indicating greater reliability and stability of the metal with the «all screw» fixation. This was a Level III retrospective comparative study. Conclusion: All the pedicle screw constructs enabled better postoperative correction, derotation, global sagittal and frontal balance, as well as a shorter fixation, compared to hybrid fixation of the spine. Level of Evidence III, Retrospective comparative study