[Radiation dosage in orthopedics -- a comparison of computer-assisted procedures].

Since the 1990s, computer-assisted methods have been well-established in the field of orthopedics and traumatology. In addition to the proven improvement in the field of surgical precisioncompared with conventional techniques, the decrease in the amount of emitted ionizing radiation inside of the operating room was cited to constitute an additional major advantage of computer-based navigation. The goal of this study was to quantify X-ray dose values exposed during both conventional methods and computer-assisted procedures, the latter being performed using a C-arm device SIREMOBIL Iso-C3D (Siemens Medical Solutions). The clinical measurements were supplemented by laboratory experiments using a pinpoint ionization chamber placed inside a standard lucite phantom. The clinical part of the study investigated the application of new, i.e. computer assisted, techniques in comparison with conventional procedures on in total 42 patients experiencing surgery either on their lower extremities (n = 14) or on the spine (n = 28). The techniques applied were: (1) conventional surgical procedure, (2) CT-based navigation, (3) C-arm navigation, and (4) Iso-C3D-navigation. The main focus of the clinical evaluation was the determination of radiation dose values by means of thermoluminescence dose meters, accompanied by the registration of the operation times of the X-ray tube during a surgical intervention. The conclusions from the clinical studies are in agreement with the results from the laboratory measurements. Computer-assisted techniques led to a significant reduction in X-ray dose exposure and drastically shortened irradiation times. The most pronounced decrease in the emission of ionizing radiation was achieved in case of the Iso-C3D-navigation, which has only recently been introduced into clinical practice, i.e. during runtime of this study.