Stop-hole osteotomy technique

r e j s o d d s v i a i he cuts that are required to create a step osteotomy of the andible or a section defect are primarily in a linear plane. he point at which 2 cuts meet is a focus for the concenration of stress and the area is prone to failure. The “stop rill hole method” has been used to block the propagation f existing crack lines during aircraft maintenance1 and in ider mechanical engineering practice, but has not been ommonly applied to avoid iatrogenic fractures in surgical ractice. A stop-hole of sufficient diameter will prolong the ime to fatigue failure under cyclical loading.2 We have developed a finite element analysis technique to imulate stress levels within bone. We tested the mandible nder normal biting forces,3 long bones with plate fixation,4 nd differing designs of osteotomy end cuts5 for bending nd torsional loading. When compared with a baseline rightngled osteotomy (maximum stress level 100%), the peak tress concentration at a bevelled osteotomy was substanially lower (70–81%). It was further reduced when the orner of a right-angled osteotomy was rounded out with stop-hole, which could be entered tangentially (40–47%) Fig. 1) or at 90◦ (44–69%) (Fig. 2). In contrast, an overut oblique osteotomy (104–158%) substantially increased he stress concentration and implied a weakening effect.5 A top-hole at the corner of an osteotomy will therefore have a