Accuracy of pedicle screw insertion: A prospective CT study in 30 low back patients

Abstract

A prospective study of the accuracy of titanium pedicle screw placement in 30 low back operations was performed. The postoperative plain radiographs and CT reformation images were evaluated by two independent radiologists. Thirty-two out of 152 screws (21%) perforated the pedicle cortex. One-tenth of the perforations was detected with conventional radiography. In ten patients (33%) all the screws were located within the pedicle. The clinical significance of this study lies in the finding that pedicle perforations are more frequent than is generally believed and that, in spite of the many malplacements, no screw that perforated by less than 4.0 m m caused neurological problems. Only one nerve root lesion was detected.

Functional outcome of computer-assisted spinal pedicle screw placement: a systematic review and meta-analysis of 23 studies including 5,992 pedicle screws

“…Biomechanical studies have shown that pedicle screws provide increased rigidity and construct stiffness compared to other posterior fixation techniques [32,33]. It is a technically demanding procedure and studies have shown an alarmingly high rate of screw misplacement varying between 21 and 39.8% with conventional insertion techniques [1][2][3]. The misplaced screws can cause three types of complications, namely neurological, vascular and mechanical.…”

“…The reported pedicle screw misplacement in historical spinal literature can be as high as [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39].8% [1][2][3], but only a small number leads to complications (neurological, vascular or visceral injuries). But these complications can be potentially life and limb threatening.…”

Independent assessment of a new pedicle probe and its ability to detect pedicle breach: a cadaveric study

“…For the purposes of our analysis, breach is defined as a pin with more than 25% of its diameter residing outside and medial, inferior, or superior to the pedicle 10 and/or a pin protruding more than 2 mm. 4,8 Independent analyses of placement of Steinmann pins were performed by 2 fellowship-trained spine surgeons and a neuroradiologist. Analysis of the CT scan included recording the following data for each pin: 1) spinal level, noting laterality, and approach used; 2) whether the pedicle had been breached (yes/no); and 3) the extent of pin protrusion for any breached pedicles (i.e., pin diameter or millimeters).…”

Reduction in Radiation (Fluoroscopy) While Maintaining Safe Placement of Pedicle Screws During Lumbar Spine Fusion

“…These scans were reviewed by an independent reviewer (AFS) Perforations < 2mm on CT scan are thought not to be associated with clinical sequelae, 22 and other authors report perforations as large as 4mm being associated with no problems. 23 Gertzbein and Robbins 24 reported an incidence of medial cortical penetration up to 8 mm with two minor neurological injuries. They hypothesize a 4mm safe zone, which includes 2mm of epidural space and 2mm of subarachnoid space.…”

“…Studies using a postoperative CT scan reviewed by independent or blinded reviewers show higher rates of perforation than those determined by radiograph. Laine et al 23 reviewed 30 low back operations. In this series of 152 pedicle screws, 32 screw perforations (21%) were detected by CT scan, whereas only 3 were detected by plain radiographs.…”