Accuracy and Safety of the Free Hand Technique for Thoracic Pedicle Screw Placement in Spinal Deformity


ABSTRACT:BACKGROUND: Pedicle screw construct has become widely accepted method for correction of spinal deformities. Better correction, higher rates of fusion as well as low complication rates have been reported. Free hand technique for placement of pedicle screw has been shown to be associated with low complication rate when performed by experienced surgeon. Low dose CT scan was used for postoperative assessment of screw placement and shown to be safe and effective method.OBJECTIVE: To determine the accuracy and safety of malpositioned screws in the thoracic spinal deformities using the free hand technique and to determine the effectiveness of the low dose CT scan regarding this issueMETHODS: 502 pedicle screws were used in 21 patients with adult idiopathic and congenital scoliosis using the free hand technique, screws positions were estimated one week postoperatively using low dose CT scan.RESULTS: Of the 502 screws inserted 262 (52.19%) were well placed inside the pedicle while 110 (21.91%) were medially misplaced and 108 screws (21.51%) were misplaced laterally, 16(3.19%) anterior perforation, 5 (1%) perforated the underlying neural foramen and 1(0.2%) perforated the upper end plate; without any significant neurological or visceral complication.CONCLUSION: Placement of the thoracic pedicle screws in the surgical correction of the deformed spine using the free hand technique is a safe, cost effective and non-time consuming and that the low dose CT scan used postoperatively is effective and safe method in detecting malpositioned screws.