| 摘要 |
The invention is relative to a system allowing to align either an instrument with a particular portion of the bone structure, or two bone segments between themselves during a fixation procedure, working under Virtual Reality conditions. In the first case, it can be used to introduce a screw, a Kirschner wire, or a drill in a body section of clinical interest, without trial drilling. In the second case, a fracture reduction and subsequent fixation can be operated eliminating doctor's X-rays exposure and greatly reducing also patient's. The system is composed by four main elements, the aiming device, provided with aiming bars, the image calibrating device (which can be coupled with the aiming device, used to determine initial angles and scales), a regulating device, connected to the fixator's clamps if a fracture reduction is required, or to the aiming device on one side and to the bone structure on the other (or to the operatory table, with a reduced precision), and a measuring device connected to a PC. This allows to present the actual alignment status in Virtual Reality on two planes once two calibration X-rays or fluoroscopies on approximately perpendicular planes have been performed and stored in the computer memory. Working principle of the system, coupling images with initially measured geometry, and the mathematical determination and visual display of the new position. The base of the aiming device is the fact that, if one aligns two planes with the body section of interest, introducing an instrument along the intersection of such planes will allow hitting the target. The aiming, coupled to the regulating device can also operate under fluoroscopy alone, needing in this case more radiation to reach the alignment. At the end of the alignment procedure, in the first case one can operate through the holes present on the aiming device, reaching the desired body portion, in the second case, one simply connects the end clamps with the desired fixator, or blocks the various degrees of freedom if the fixator carries its own regulating device. |
