Accuracy and safety of pedicle screw placement in neuromuscular scoliosis with free-hand technique

Abstract

It is a retrospective analytic study of 1,009 transpedicular screws (689 thoracic and 320 lumbosacral), inserted with free-hand technique in neuromuscular scoliosis using postoperative CT scan. The aim of paper was to determine the accuracy and safety of transpedicular screw placement with free-hand technique in neuromuscular scoliosis and to compare the accuracy at different levels in such population. All studies regarding accuracy and safety of pedicle screw in scoliosis represent idiopathic scoliosis using various techniques such as free-hand, navigation, image intensifier, etc., for screw insertion. Anatomies of vertebrae and pedicle are distorted in scoliosis, hence accurate and safe placement of pedicle screw is prerequisite for surgery. Between 2004 and 2006, 37 consecutive patients, average age 20 years (9-44 years), of neuromuscular scoliosis were operated with posterior pedicle screw fixation using free-hand technique. Accuracy of pedicle screws was studied on postoperative CT scan. Placement up to 2 mm medial side and 4 mm lateral side was considered within-safe zone. Of the 1,009 screws, 273 screws were displaced medially, laterally or on the anterior side showing that 73% screws (68% in thoracic and 82.5% in lumbar spine) were accurately placed within pedicle. Considering the safe zone, 93.3% (942/1009, 92.4% in thoracic and 95.3% in lumbar spine) of the screws were within the safe zone. Comparing accuracy according to severity of curve, accuracy was 75% in group 1 (curve \90°) and 69% in group 2 (curve [90°) with a safety of 94.8 and 91.2%, respectively (P = 0.35). Comparing the accuracy at different thoracic levels, it showed 67, 64 and 72% accuracy in upper, middle and lower thoracic levels with safety of 96.6, 89.2 and 93.1%, respectively, exhibiting no statistical significant difference (P = 0.17). Pedicle screw placement in neuromuscular scoliosis with free-hand technique is accurate and safe as other conditions.

Benefit and accuracy of intraoperative 3D-imaging after pedicle screw placement: a prospective study in stabilizing thoracolumbar fractures

“…Several authors favour the exclusive implantation of the screws on the basis of anatomical landmarks both in the upper area of the thoracic spine and for spines with scoliotic deformations [19,25]. Schizas reports of a rate of 11.7% falsely positioned screws in the area T1-T6, but with no need for operative revision [25].…”

“…Schizas reports of a rate of 11.7% falsely positioned screws in the area T1-T6, but with no need for operative revision [25]. Of 1,009 manually inserted pedicle screws in cases of scoliosis, 73% were intrapedicular, 20.3% penetrated the pedicle limits in an acceptable false position and 6.7% of the screws were classified as requiring revision [19].…”

Use of the Universal Clamp for deformity correction and as an adjunct to fusion: Preliminary results in scoliosis

“…Aside from risks associated with placing screws outside of the pedicle [9][10][11][12], there is growing concern over the low values of thoracic kyphosis often reported in patients with all-screw constructs [2,7,13,14]. Other treatments consist of various types of hybrid constructs with pedicle-screw fixation in the lumbar spine and other anchors in the thoracic spine [3,13,15].…”

Stimulation of Pedicle Screws with Diathermy: Is it a Viable Option to Detect Breaches?

“…Nine false negative cases with medial breaches [1.92%] were detected on postoperative CT, five being in the thoracic and four being in the lumbosacral spine ( Figure 2). These breaches were however less than 2 mm and asymptomatic [8]. Considering this, this method demonstrated sensitivity, specificity, positive predictive value and negative predictive value of 97.63%, 100%, 100% and 21.43%, respectively.…”