Clinical experience of Gamma nailing with fluoro-navigation

摘要

Objectives: To study the application of fluoro-navigation in Gamma nailing for peritrochanteric fractures. Background: The minimally invasiveness of Gamma nail in the fixation of peritrochanteric fractures is well accepted [2]. However, frequent fluoroscopic control during operation is needed to ensure accurate position of the femoral components as well as the lag screw in femoral head and neck. As these procedures are usually controlled with frontal and sagittal views of the proximal femur, the use of fluoro-navigation will be able to minimize intraoperative fluoroscopic control and hence exposure to X-ray [1]. In this study, application of fluoro-navigation in Gamma nailing was explored and the advantages were further investigated. Design/Methods: Siemens SIREMOBIL Iso-C fluoroscope with specially fitted C-arm tracker and phantom were used. The Stryker Leibinger navigation system with Virtual fluoroscopy version 2.01 was used in the operation. Specially designed lag screw sleeve tracker attachment was adapted to the standard Gamma nail instrument. 41 trochanteric fractures were studied. Reduced under fluoroscopic control and stabilized by longitudinal traction on a traction table were done. Sterilization and draping were done from anterior superior iliac crest to distal thigh. A patient tracker was inserted into the anterior iliac crest through a small incision with the tracker facing distally. The navigation system was switched on and accuracy validated. The C-arm tracker was registered and both frontal and lateral images of the proximal femur were taken and registered for navigation. A curved and cannulated awl was then point calibrated with a tool tracker mounted and used to locate the site of incision at the proximal femur for entry to the medullary canal. A 3cm incision was made at tip of the greater trochanter after localization and the calibrated curved awl was inserted and entered the proximal femur through the tip of the greater trochanter under navigation guidance. A guide wire is inserted through the cannulated awl. A Gamma nail was then inserted onto the guide wire into the femur. The lag screw sleeve was then calibrated and attached to the proximal targeting jig. The Gamma nail was then further inserted down to the femoral canal with the axis of the lag screw monitored with the navigation on the frontal and lateral views. When the axis of the lag screw was in the ideal position, a 2cm incision was made and the lag screw sleeve was inserted until it was in contact with the lateral cortex. The lag screw length was then measured with the extension of the virtual tip and the position of the screw was also planned. The standard operative procedure of lag screw insertion was then carried out. Distal locking screw can also be inserted with the navigation system. In the study, the length of the incision, the total operation time, the number of images taken and the position of the implants were analyzed. Complications were noted during surgery.