Freehand power-assisted pedicle screw placement in scoliotic patients: results on 5522 consecutive pedicle screws

Abstract

Pedicle screws is the current gold standard in spine surgery, achieving a solid tricolumnar fixation which is unreachable by wires and hooks. The freehand technique is the most widely adopted for pedicle screws placing. While freehand technique has been classically performed with manual tools, there has been a recent trend toward the use of power tools. However, placing a pedicle screw remains a technically demanding procedure with significant risk of complications. The aim of this article is to retrospectively evaluate safety and accuracy of free-hand power-assisted pedicle screw placement in a cohort of patients who underwent correction and fusion surgery for scoliosis (both idiopathic and non-idiopathic) in our department. A retrospective review of all patients with scoliosis who underwent surgery and received a postoperative CT scan in our department in a 9-year period was undertaken. Screw density, number and location of pedicle screws were measured using pre and postoperative full-length standing and lateral supine side-bending radiographs. Then, postoperative CT scan was used to assess the accuracy of screw placement according to Gertzbein-Robbins scale. Malpositioned screws were divided according to their displacement direction. Finally, intra and postoperative neurological complications and the need for revision of misplaced screws were recorded. A total of 205 patients were included, with a follow-up of 64.9 ± 38.67 months. All constructs were high density (average density 1.97 ± 0.04), and the average number of fusion levels was 13.72 ± 1.97. A total of 5522 screws were placed: 5308 (96.12%) were grade A, 141 (2.5%) grade B, 73 (1.32%) grade C. Neither grade D nor grade E trajectories were found. The absolute accuracy (grade A) rate was 96.12% (5308/5522) and the effective accuracy (within the safe zone, grade A + B) was 98.6% (5449/5522). Of the 73 misplaced screws (grade C), 59 were lateral (80.80%), 8 anterior (10.95%) and 6 medial (8.22%); 58 were in convexity, while 15 were in concavity (the difference was not statistically significant, p = 0.33). Intraoperatively, neither neurological nor vascular complications were recorded. Postoperatively, 4 screws needed revision (0.072% of the total): Power-assisted pedicle screw placing may be a safe an accurate technique in the scoliosis surgery, both of idiopathic and non-idiopathic etiology. Further, and higher quality, research is necessary in order to better assess the results of this relatively emerging technique.

The Child’s Age and the Size of the Curvature Do Not Affect the Accuracy of Screw Placement with the Free-Hand Technique in Spinal Deformities in Children and Adolescents

“…Skaggs et al, in a large multicenter study, reported 99.9% of pedicle screws placed with power pedicle preparation did not have complications or require revision, while 0.5% of screws underwent revision for an asymptomatic lateral breech and for a spinal headache/medial breech [ 24 ]. In the study of the accuracy of screw placement using power [ 51 ], a total of 5522 screws were placed: 96.12% were grade A. The effective accuracy (within the safe zone, grade 1 and 2) was 98.6%.…”

“…The effective accuracy (within the safe zone, grade 1 and 2) was 98.6%. No neurological, vascular, or visceral complications were recorded, but four screws needed revision (0.072% of the total) [ 51 ]. The use of robotic-assisted thoracic screw placement was studied by Macke et al [ 25 ].…”

Long-term reoperation rates following spinal fusion for neuromuscular scoliosis in nonambulatory patients with cerebral palsy

“…At that time, the most common fixation technique at our institution was the Luque-Galveston technique with all sublaminar wires (52.0%) or hybrid constructs (46.6%), which included a combination of sublaminar wires, hooks, and/or pedicle screws. Pedicle screw instrumentation is currently the most common instrumentation for posterior spinal fusion due to its ability to achieve stronger segmental fixation and the concept of three-column fixation [6,25]. Thus, our findings may differ from long-term outcomes for present-day patients who receive all-pedicle screw instrumentation.…”