Accuracy of Pedicle Screw Insertion and Its Effects on Outcome of Patients

Regarding the indication of pedicle screw insertion and different reports on prevalence of malposition and related factors, in order to determine the malpositions and its effects on prognosis of patients, this survey was performed on patients admitted in Imam Hossein Hospital betweem 2005-2007. This study was a case-series one. All the patients whom had the indication of pedicle screw insertion were evaluated and the cases with skeptisism about non-fusion or difficulty in follow up were excluded from the study. Grading of pedicel screw insertion determined by post-operation CT-Scan. Then efficacy of level, type of surgery and direction of screws surveyed statistically. Effect of malposition of screw at correction of spinal deformity also determined. 35 patients with 206 pedicle screw surveyed. 26 screws (12.0%) had malposition. This had a relationship with thoracic level and spine fracture (P<0.02). In 15% of correct screws and 20% of malpositioned screws there was no correction of deformity after operation. However, these rates changed into 30% and 20%, respectively, during the follow up. It seems that prevalence of pedicle screw malformation is acceptable and perhaps, re-operation for correction of malposition screws is not necessary. However, further experimental studies are on demand.