Computer-Assisted Navigation in Craniomaxillofacial Tumors

Computer-assisted navigation in bone tumor surgery: seamless workflow model and evolution of technique

BACKGROUND

Computer-assisted navigation was recently introduced to aid the resection of musculoskeletal tumors. However, it has not always been possible to directly navigate the osteotomy with real-time manipulation of available surgical tools. Registration techniques vary, although most existing systems use some form of surface matching.

QUESTIONS/PURPOSES

We developed and evaluated a workflow model of computer-assisted bone tumor surgery and evaluated (1) the applicability of currently available software to different bones; (2) the accuracy of the navigated excision; and (3) the accuracy of a new registration technique of fluoro-CT matching.

METHODS

Our workflow involved detailed preoperative planning with CT-MRI image fusion, three-dimensional mapping of the tumor, and planning of the resection plane. Using the workflow model, we reviewed 15 navigation procedures in 12 patients, including four with joint-saving resections and three with custom implant reconstructions. Intraoperatively, registration was performed with either paired points and surface matching (Group 1, n = 10) or a new technique of fluoro-CT image matching (Group 2, n = 5). All osteotomies were performed under direct computer navigation. Postoperatively, each case was evaluated for histologic margin and gross measurement of the achieved surgical margin.

RESULTS

The margins were free from tumor in all resected specimens. In the Group 1 procedures, the correlation between preoperative planned margins and actual achieved margins was 0.631, whereas in Group 2 procedures (fluoro-CT matching), the correlation was 0.985.

CONCLUSIONS

Our findings suggest computer-assisted navigation is accurate and useful for bone tumor surgery. The new registration technique using fluoro-CT matching may allow more accurate resection of margins.

Computer-Aided Maxillofacial Surgery: An Update

Introduction. Recent developments in technology have revolutionized medicine and surgery. This article aims at providing an update on the current trends in computer-aided maxillofacial surgery and illustrates these advances with clinical cases. Methods. The PubMed database was searched for articles published during the past 5 years using the keywords “maxillofacial” and “surgery, computer-assisted.” Full texts of relevant articles were retrieved, and their study details were extracted. Results. Among the 133 articles, most focused on cone-beam computed tomography (CBCT), stereophotography, surgical panning software, and intraoperative navigation. Stereophotography produces 3D facial photographs with natural color and texture, whereas CBCT generates excellent hard-tissue images with a substantially lower radiation than conventional CT scans. Information gathered from CBCT and stereophotography can be used for accurate diagnosis, virtual planning, and simulation of surgery with the aid of specialized software. The preplanned treatment can be executed accurately via intraoperative surgical navigation. Conclusion. Tremendous potential exists for computer-aided maxillofacial surgery as it moves from research to clinical care.

Computer planning and intraoperative navigation in cranio-maxillofacial surgery

Preoperative computer design and stereolithographic modeling combined with intraoperative navigation provide a useful guide for and possibly more accurate reconstruction of a variety of complex cranio-maxillofacial deformities. Although probably not necessary for routine use, the author's early experience confirms that of other surgeons with more than a decade of experience: computer-assisted surgery is indicated for complex posttraumatic or postablative reconstruction of the orbits, cranium, maxilla, and mandible; total temporomandibular joint replacement; orthognathic surgery; and complex dental/craniofacial implantology. Further study is needed to provide outcomes data and cost-benefit analyses for each of these indications.

Introduction of e-learning in dental radiology reveals significantly improved results in final examination

PURPOSE

Because a traditionally instructed dental radiology lecture course is very time-consuming and labour-intensive, online courseware, including an interactive-learning module, was implemented to support the lectures. The purpose of this study was to evaluate the perceptions of students who have worked with web-based courseware as well as the effect on their results in final examinations.

MATERIALS AND METHODS

Users (n(3+4)=138) had access to the e-program from any networked computer at any time. Two groups (n(3)=71, n(4)=67) had to pass a final exam after using the e-course. Results were compared with two groups (n(1)=42, n(2)=48) who had studied the same content by attending traditional lectures. In addition a survey of the students was statistically evaluated.

RESULTS

Most of the respondents reported a positive attitude towards e-learning and would have appreciated more access to computer-assisted instruction. Two years after initiating the e-course the failure rate in the final examination dropped significantly, from 40% to less than 2%.

CONCLUSIONS

The very positive response to the e-program and improved test scores demonstrated the effectiveness of our e-course as a learning aid. Interactive modules in step with clinical practice provided learning that is not achieved by traditional teaching methods alone. To what extent staff savings are possible is part of a further study.