Biomedical subjects

Musa Citak

Publications and source records attributed to Musa Citak.

4 recordsLinked to original sources

PubMed2007

Experimental validation of noninvasive referencing in navigated procedures on long bones.

Navigation procedures in orthopedic surgery require fixation of reference markers to the anatomic region of interest. Inadequate fixation might lead to micromotion or loosening of the reference marker, consequently causing registration failures or errors in navigation. Osseous rigid fixation is usually achieved by minimally invasive Schanz screws or pins. The goal of this study was to evaluate a non invasive external fixation device, a headband so far used in cranial navigation, as an alternative invasive fixation technique to reference markers in the femur. A common navigation system with an adapted trauma software application was used to track the positions of the soft tissue-attached headband relative to an invasive reference marker on the femur during manipulations of the thigh. Relative translative and rotational movements of the headband were measured during defined movements of the hip and knee and manipulations of the headband itself. The results revealed high translative and rotational movements, up to 6 mm and 3 degrees , respectively, due to minor manipulations of the affected lower extremity. Noninvasive soft tissue fixation with a headband does not allow rigid fixation for accurate navigated registration or operative procedures at the femur. Necessary intraoperative movements or manipulations would cause substantial registration failures. Invasive fixation techniques with screws or pins are still the method of choice.

Bone Screws↗

PubMed2005

Navigated Iso-C3D-based percutaneous osteoid osteoma resection: a preliminary clinical report.

Minimally invasive osteoid osteoma resection under computer tomography (CT) guidance has yielded good results and has become a viable alternative to open surgical procedures. Limited visualization of the actual drill position under CT guidance can frequently result in inadequate and malpositioned drilling, especially at lesions located in less accessible anatomic regions. With the conventional CT-guided drilling technique, sterility and general operative management poorly correlate with standard operating room conditions, and are at risk of intra- and postoperative complications. The new Iso-C(3D) imaging device provides intraoperative multiplanar reconstructions. Adequate image quality and implementation in navigation systems were described for numerous indications. On the basis of multiplanar reconstructions, minimally invasive navigated techniques under three-dimensional surgical tool control become possible, which is not the case under fluoroscopic or CT-based navigation. We report on our first three cases of navigated Iso-C(3D) osteoid osteoma resection. A minimally invasive resection of the nidus was possible under permanent multiplanar image control. No complications were encountered and all patients reported successful outcomes. Minimally invasive-based navigation offered an effective and reproducible surgical approach. Dependence on CT imaging for proper positioning and complications associated with use away from the operating room environment can be avoided.

Bone Neoplasms↗

PubMed2004

Computer aided tumor resection in the pelvis.

Surgical treatment of malignant tumors within the pelvis is a complex problem due to the anatomy and biomechanics. There are standardized preoperative diagnostic tools like computed tomography (CT) or magnetic resonance imaging (MRI) that provide multidimensional information. However, this information cannot be transferred intraoperatively. Computer aided orthopedic surgery (CAOS) may be a solution for precise intraoperative accuracy for these indications. We report on two patients with tumors within the pelvis. In one patient, an infiltrating recurrent chordoma within the sacrum was resected with CAOS. The other patient presented with a periacetabular chondrosarcoma. Resection was done with navigation so precise that a custom-made hemipelvis prosthesis with a special coating fit. In both patients, a complete resection was achieved with tumor-free resection margins. Navigation may be helpful in tumor surgery within the pelvis.

Bone Neoplasms↗

PubMed2003

Computer assisted pelvic surgery: registration based on a modified external fixator.

A fundamental step in Computer Assisted Surgery (CAS) is the registration, when the preoperative virtual data and the corresponding operative anatomy of the region of interest are merged. To provide exact landmarks for anatomical registration, a tubular external fixator was modified. Two intact pelvic bones (one artificial foam pelvis and one cadaver specimen) were used for the experimental setup. Registration was carried out using a standardized protocol for anatomy-based registration in the control group; anatomical registration was achieved using a modified external fixator in the study group. This external fixator had titanium fiducials wedged into the fixator carbon tubes serving as landmarks for paired-point registration. The tubes were used for surface registration. The standard anterior pelvis fixator assembly was augmented with additional bilateral tubes oriented towards the posterior, enabling registration of the sacroiliac areas. The accuracy of registration was checked by "reversed verification", where the examiner used only the screen display to control the virtual position of the pointer tip in relation to selected landmarks. By virtual matching, the real distance was measured with a digital caliper. We defined the verification as "accurate" when the residual distance was less than 1 mm; "acceptable" when it was between 1 mm and 2 mm; and "insufficient" when it exceeded 2 mm. The paired T-test with significance levels of p < 0.05 was used for statistical analysis. The anatomical registration based on the external fixator landmarks was statistically as accurate as that obtained using anatomical landmarks on the pelvic bone. This study concludes that the external fixator, a conventional tool in the management of acute traumatic pelvic instability, can also be useful for landmark registration in CAS.

External Fixators↗