Watzinger F, Birkfellner W, Wanschitz F, Ziya F, Wagner A, Kremser J, Kainberger F, Huber K, Bergmann H, Ewers R
University Clinic of Oral and Maxillofacial Surgery, Ludwig-Boltzmann Institute of Nuclear Medicine, University of Vienna, Austria.
Plast Reconstr Surg. 2001 Mar;107(3):659-67. doi: 10.1097/00006534-200103000-00003.
Endosteal implants facilitate obturator prosthesis fixation in tumor patients after maxillectomy. Previous clinical studies have shown, however, that the survival of implants placed into available bone after maxillectomy is generally poor. Nevertheless, implants positioned optimally in residual zygomatic bone provide superior stability from a biomechanical point of view. In a pilot study, the authors assessed the precision of VISIT, a computer-aided surgical navigation system dedicated to the placement of endosteal implants in the maxillofacial area. Five cadaver specimens underwent hemimaxillectomy. The cadaver head was matched to a preoperative high-resolution computed tomograph by using implanted surgical microscrews as fiducial markers. The position of a surgical drill relative to the cadaver head was determined with an optical tracking system. Implants were placed into the zygomatic arch, where maximum bone volume was available. The results were assessed using tests for localization accuracy and postoperative computed tomographic scans of the cadaver specimens. The localization accuracy of landmarks on the bony skull was 0.6 +/- 0.3 mm (average +/- SD), as determined with a 5-df pointer probe; the localization accuracy of the tip of the implant burr was 1.7 +/- 0.4 mm. The accuracy of the implant position compared with the planned position was 1.3 +/- 0.8 mm for the external perforation of the zygoma and 1.7 +/-1.3 mm for the internal perforation. Eight of 10 implants were inserted with maximal contact to surrounding bone, and two implants were located unfavorably. Reliable placement of implants in this region is difficult to achieve. The technique described in this article may be very helpful in the management of patients after maxillary resection with poor support for obturator prostheses.
骨内种植体有助于上颌骨切除术后肿瘤患者的赝复体固定。然而，以往的临床研究表明，上颌骨切除术后植入可用骨中的种植体存活率通常较低。尽管如此，从生物力学角度来看，在残余颧骨中最佳定位的种植体可提供更好的稳定性。在一项初步研究中，作者评估了VISIT（一种专门用于在颌面区域植入骨内种植体的计算机辅助手术导航系统）的精度。对五具尸体标本进行了半侧上颌骨切除术。通过使用植入的手术微螺钉作为基准标记，将尸体头部与术前高分辨率计算机断层扫描进行匹配。使用光学跟踪系统确定手术钻头相对于尸体头部的位置。将种植体植入颧骨弓，此处有最大的骨量。使用定位精度测试和尸体标本的术后计算机断层扫描对结果进行评估。用5自由度指针探头测定，颅骨上标志点的定位精度为0.6±0.3mm（平均值±标准差）；种植体钻尖的定位精度为1.7±0.4mm。与计划位置相比，颧骨外侧穿孔处种植体位置的精度为1.3±0.8mm，内侧穿孔处为1.7±1.3mm。10枚种植体中有8枚插入时与周围骨有最大接触，2枚种植体位置不佳。在该区域可靠地植入种植体很难实现。本文所述技术可能对上颌骨切除术后对赝复体支持不佳的患者的治疗非常有帮助。
