Use of pedicle screw (PS) systems for spinal stabilization has become increasingly common in spine surgery. The technique and principle for pedicle screw instrumentation as well as anatomical landmarks of screw placement, however are common to all systems. The purpose of this study is to compare accuracy of pedicle screw placement with conventional and navigation techniques.
Aim: To compare the accuracy of pedicle screw positioning between conventional and a new navigation system for the spine.
Materials and Methods: It was a retrospective study in which 40 patients were randomly selected during the period between Jun-2014 to Jun-2016, operated for posterior fixation either through conventional and navigational spine surgery. Two independent observers analysed digital axial CT slices of all instrumented pedicles, with individual and consensus interpretation for each screw. A simple grading system (LAINE’s grading) was devised for evaluation of screw position.
Results and Discussion: Overall accuracy of navigation technique is 95.89% (140/146) with 6 PS breach with laine’s grade 1 error all occurs in thoracic level, doesn’t results into any type of complications in manner of neurologic deficit or CSF leakage or dural tear etc. Overall accuracy of conventional PS placement is 89.84% (113/128) with 4 PS having grade 2 error and 11 PS having grade 3 error mainly occurs in thoracic level but none causes complication in any form i.e.; neurologic deficit, CSF leak, revision surgery etc.
Conclusion: From our study, despite of high cost, preoperative registration and matching, more steep learning curve, needful of technician throught surgery, navigation surgery is better option in thoracic PS placement and spinal deformities due to complex morphology and anatomy of thoracic pedicles with rib cage obscuring fluoroscopic visualization making conventional surgery difficult with high rate of pedicle breach.