Computer-assisted localization of osteoid osteoma: an initial experience

Percutaneous excision of difficult osteoid osteomas using intraoperative AIRO CT navigation: a preliminary report

Osteoid osteomas are well known for intraoperative technical difficulties for localization and adequate excision, especially when they are not clearly visualized on plain radiographs or when they occur in difficult and inaccessible situations. Localization in the radiology suite and shifting the patient to the operating room can be cumbersome, and can result in errors because of lack of real-time imaging. In these scenarios, intraoperative navigation will be useful. We report a technique of intraoperative computed tomography (CT) navigation for localization and excision of osteoid osteomas of the long bones. Six patients (four femoral and two tibial lesions) with a radiological diagnosis of osteoid osteoma, in whom the nidus could not be visualized clearly on plain radiographs, were treated with this technique. Intraoperative CT navigation with AIRO was performed and the images were registered to the computer. The lesion was then localized and excised using a high-speed burr. All patients underwent postexcision on-table CT scans, which showed complete excision of the nidus. All patients became symptom free and are doing well at a minimum follow-up of 6 months. Intraoperative CT navigation helps to exactly localize the nidus and also helps to confirm complete excision of the nidus. This is a safe, effective and minimally invasive method to treat osteoid osteomas, particularly those that are not amenable to excision under C arm guidance.

Potential use of computer navigation in the treatment of primary benign and malignant tumors in children

The treatment of benign and malignant primary bone tumors has progressed over time from relatively simple practice to complex resection and reconstruction techniques. Recently, computer-assisted orthopaedic surgery (CAOS) has been used to assist surgeons to enhance surgical precision in order to achieve these goals. Initially, software developed for CT-based spinal applications was used to perform simple intraoperative point localization. With advances in technique and software design, oncology surgeons have now performed joint sparing complex multiplanar osteotomies using combined CT and MRI image data with precision and accuracy. The purpose of this paper is to provide a review of the clinical progress to date, the different types of navigation available, methods for error management, and limitations of CAOS in the treatment of pediatric benign and malignant primary bone tumors.

The effect of anatomic landmark selection of the distal humerus on registration accuracy in computer-assisted elbow surgery

Incorrect selection of the flexion-extension axis of the elbow may be an important cause of failure following total elbow arthroplasty. Axis selection can be improved by locating it on a pre-operative image and registering the image to the subject intra-operatively. However, registration is dependent on the availability of anatomic landmarks that may be distorted or absent because of tumors, arthritis, dislocations, or fractures. This study determined the anatomic landmarks required to register surface data accurately to a pre-operative image of the distal humerus. Registration error for landmarks unlikely to be compromised by severe bone loss was 1.1 +/- 0.2 mm in translation and 0.4 +/- 0.1 degrees in rotation. These results suggest that a close alignment of a pre-operative image with intra-operative surface data can be achieved using only a relatively small portion of the distal humerus that is readily available to the surgeon, and unlikely to be compromised, even in the setting of significant articular bone loss.