Bone segment navigation: Difference between revisions

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10.1097/00006534-198606000-00001
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== Transferring the preoperative planning to the operating theatre ==
[[Image:SSNSchema.jpg|thumb|left|Schematic representation of the principle of bone segment navigation; DRF1 and DRF2 = IR Reference devices]]
 
The usefulness of the preoperative planning, no matter how accurate, depends on the accuracy of the reproduction of the simulated [[osteotomy]] in the surgical field. The transfer of the planning was mainly based on the surgeon's visual skills. Different guiding headframes were further developed to mechanically guide bone fragment repositioning. Such a headframe is attached to the patient's head, during CT or MRI, and surgery. There are certain difficulties in using this device. First, exact reproducibility of the headframe position on the patient's head is needed, both during CT or MRI registration, and during surgery. The headframe is relatively uncomfortable to wear, and very difficult or even impossible to use on small children, who can be uncooperative during medical procedures. For this reason headframes have been abandoned in favor of frameless stereotaxy of the mobilized segments with respect to the skull base. Intraoperative registration of the patient's anatomy with the computer model is done such that pre-CT placement of fiducial points is not necessary.
 
[[Image:SSNimOP.jpg|thumb|Using the [[Surgical Segment Navigator|SSN]] in the operating theatre; 1=IR receiver, 2 and 4=IR Reference devices, 3=SSN-Workstation]]
[[Image:SSNSchema.jpg|thumb|Schematic representation of the principle of bone segment navigation; DRF1 and DRF2 = IR Reference devices]]
 
== Surgical Segment Navigator ==