Navigated femoral shaft fracture treatment: current status.

Femoral malrotation is a common complication after internal fixation of a femoral shaft fracture. The only valid, objective monitoring method is computer tomography-assisted torsion measurement between the proximal and distal femur; unfortunately, this can only be carried out postoperatively. A difference of 15° compared to the contralateral femur is seen as an indication for revision. With the development of computer-assisted surgery, new possibilities for performing torsion control and correction intraoperatively has been introduced. These methods also allow for navigation-assisted definition of the optimal incision site, intramedullary access, femoral nail and interlocking. The main problem lies in the extra time of surgery, which is due to performing all the steps of the surgery navigated. The solution for this problem is "hybrid navigation", in which the surgeon can select the steps he needs from the navigation system, depending on his experience or surgical technique.

Sustained risk of recurrent thromboembolic events in patients with patent foramen ovale and paradoxical embolism: long-term follow-up over more than 15 years.

BACKGROUND: Patients with patent foramen ovale (PFO) and cryptogenic stroke are at risk of recurrence. Therapeutic regimens range from no treatment to anticoagulation treatment to surgical or interventional closure. However, long-term follow-up is only available for up to 4 years. METHODS: Among ~5,000 transesophageal echocardiographies in stroke/TIA-patients between 1988 and 1997, a PFO was found and considered a possible mediator for the neurological event in 97 patients. In these patients, the PFO was judged to be responsible for the neurological event. Patients with cardiac or other reasons for embolism were excluded. The therapy for stroke was chosen by the attending physician. Follow-up information was obtained through telephone interviews. RESULTS: Follow-up was available for 86 patients (89%) with a mean period of 15.4 years (range, 11.2-25.9 years). Thirteen patients (15%) suffered from recurrent ischemic events (7 TIAs, 5 strokes, 1 peripheral embolism) after a mean period of 4.9 years. Four patients died, not associated with recurrent thromboembolism. The risk of recurrence was increased over the entire length of the mean follow-up period. The occurrence of recurrent events was not associated with differences in baseline data, the presence of ASA, PFO size or the chosen treatment. CONCLUSION: In patients with paradoxical embolism, recurrent ischemic events are frequent despite medical therapy. These events are not limited to the early years after the index event; this long-term follow-up revealed a risk of occurrence over the entire follow-up. These patients have a sustained risk of recurrence, requiring lifetime protection, which should be considered in tailoring individual therapeutic strategies.

Transcatheter closure of patent foramen ovale (PFO) in patients with paradoxical embolism: procedural and follow-up results after implantation of the Amplatzer®-occluder device.

BACKGROUND: Prevalence of patent foramen ovale (PFO) with detectable right-to-left shunt is higher in young adults with transient ischemic attack (TIA) and stroke compared to the general population. So far, published series included different occluder systems, various indications and regimens of postprocedural anticoagulation. In our experience, occluder systems may be associated with an increased prevalence of thrombus formation, which has also reported by other groups. The aim of the present study was to evaluate the follow-up results after implantation of the Amplatzer® occluder in patients with PFO using a consistent anticoagulation regimen. METHODS AND RESULTS: One-hundred and fourteen patients with PFO (60 men; age: 47 ± 13 years) and ≥1 thromboembolic event were included. Other causes for embolism were excluded. PFO-closure was successful in all patients. All patients were treated with aspirin (100 mg/day) and clopidogrel (75 mg/day) for 6 months. TEE was repeated at a mean of 10.3 months. Mean clinical follow-up period was 18 ± 9 months. After a mean of 10 months, no patient had either a significant residual shunt nor a suspected thrombus formation on the occluder. During follow-up, 5 patients suffered from neurological events (1 stroke, 2 TIAs, 2 epileptic seizures), though complete closure of the PFO was documented by TEE. One patient suffered from bleeding complications (upper GI-bleeding). CONCLUSION: Percutaneous closure of PFO in symptomatic patients by Amplatzer® occluder represents an effective therapy with a low incidence of peri-interventional complications and recurrent thromboembolism. Thrombus formations on the occluder system were not detected in this cohort.

Complete dislocation of the talus: a case report using intraoperative 3D fluoroscopy.

INTRODUCTION: In a complete dislocation of the talus, the talus is stripped of all its ligament connections in the triple articulated ankle joint. This case report describes the treatment and the 3-year follow-up of a complete dislocation of the talus with the use of intraoperative 3D imaging. PATIENTS AND METHODS: The 19-year-old patient was involved as a driver in a car accident. After the radiological diagnosis of a complete talus dislocation, an emergency operation was performed due to the critical soft tissue condition. The ISO-C3D fluoroscope from the company Siemens (Erlangen, Germany) was utilized for reduction control. RESULTS: Follow-up evaluations were completed three years after the treatment, the patient had no complaints. DISCUSSION: Since these types of serious injuries are always combined with severe soft tissue damage, the main goals of this treatment have to be debridement and minimized iatrogenic surgical damage. By using intraoperative 3D imaging, immediate reduction control is available, so that revision operations can be avoided. CONCLUSION: Complete dislocation of the talus is an extremely rare injury, which may cause serious complications. A fast and careful reduction, whether open or closed, should be the goal of treatment. Successful reduction can be determined intraoperatively with the use of 3D imaging.

A customized modular reference array clamp for navigated spine surgery.

INTRODUCTION: The current authors have developed a modular system of reference array fixation which is tailored specifically to the spinal level being operated upon. They believe that this system may further increase the precision and accuracy of pedicle screw placement. MATERIALS AND METHODS: Two formalin-fixed whole body cadavers were used for this study. For cervical spine evaluation of the reference clamp, four odontoid screws (two per cadaver) for C1/C2-fusion and four lateral mass screws (two per cadaver) were implanted. Following navigated screw placement with 2D and 3D fluoroscopic verification, insertion of two lateral mass screws was performed. In the same way, lumbar and thoracic pedicle screws were implanted. Two pedicle screws were placed at two levels of the lumbar and two levels of the thoracic areas giving an overall of 16 screws implanted (8 cervical, 4 thoracic, and 4 lumbar). Postoperative evaluation involved comparison of postoperative 3D scans and preoperative planning images. A simple classification system was used for evaluation of any deviation from the planned trajectory. RESULTS: All pedicle screw placements were performed as planned without any technical problems. The reference array clamps remained in position at all the spinal levels at which they were employed with no loosening or displacement and no secondary damage to any of the spinous processes. Manual manipulation was performed but no displacement or slippage was observed. Image artefacts caused by the reference clamp were not significant as to obscure the area of interest. Both imaging modalities (Iso-C 3D and Vario 3D) generated sufficiently precise 3D images. There was no substantial difference in quality when those two systems were compared. DISCUSSION: Insufficient fixation of the reference clamp can lead to failure and complications. To date, no reference clamp systems have been developed specifically for navigated spine surgery. CONCLUSIONS: Stable reference array fixation is a critical step in navigated surgery. To date, the same reference clamps have been applied to the spinal anatomy as have been developed originally for the appendicular skeleton. The current investigators have developed a novel modular clamp and have demonstrated its efficacy in a cadaveric model.