Timo Stübig

Intraoperative 3D imaging: value and consequences in 248 cases.

BACKGROUND Intraoperative visualization of articular surfaces is technically demanding, and standard two-dimensional fluoroscopic imaging frequently does not provide adequate detail of nonplanar joints. New imaging modalities allow for intraoperative 3D visualization, which are useful in articular fractures. Purpose of this study was to evaluate the utility of 3D imaging in articular fracture reconstruction. METHODS In a prospective cohort study, we evaluated 248 consecutive patients with intra-articular fractures. After fracture fixation using standard fluoroscopy, 3D imaging was performed intraoperatively using the Iso-C3D system for all patients. Surgeons filled out questionnaires regarding the utility and perceived accuracy of the 3D system. Postoperative CT scans were performed on approximately half of the patients. Main outcome measurements were based on the surgeons decision to immediately revise the articular reduction or implant position. The setup time for the system was recorded. For patients with postoperative CT scans, articular surface gaps of 2 mm or intra-articular hardware placement was again evaluated. RESULTS In 19% of all cases, intraoperative image analysis resulted in immediate adjustment of the reduction or hardware exchange. These revisions were based on Iso-C3D views of the articular surface that were not visible using fluoroscopy. Of the 129 postoperative CT scans, five cases revealed a technical error of the joint reconstruction, and a secondary revision procedure was performed. CONCLUSION In conclusion, the Iso-C3D was a valuable intraoperative tool, providing additional information about the articular surface compared with conventional fluoroscopy in a variety of anatomic regions.

Alcohol intoxication in road traffic accidents leads to higher impact speed difference, higher ISS and MAIS, and higher preclinical mortality

Alcohol is one of the most important personal risk factors for serious and fatal injuries, contributing to approximately one third of all deaths from accidents. It is also described that alcohol intoxication leads to a higher mortality in the clinical course. In this study, we hypothesized that alcohol intoxication leads to different accident kinematics, a higher ISS (Injury Severity Score), and higher preclinical mortality compared to sober patients. A technical and medical investigation of alcohol intoxicated road users was performed on the scene of the crash and at the primary admitting hospital. Alcohol testing was performed with either breath alcohol tests or measurement of blood alcohol concentration (BAC) in a standard laboratory test. Between 1999 and 2010, 37,635 road traffic accidents were evaluated by the Accident Research Unit. Overall 20,741 patients were injured, 2.3% of the patients were killed. Among the injured patients, 2.2% with negative BAC were killed, compared to 4.6% fatal injuries in patients with a positive BAC (p < 0.0001). Of the patients with a positive BAC, 8.0% were severely injured, compared to 3.6% in the BAC negative group (p < 0.0001). Regarding the relative speed at impact (Δv for motorized drivers, vehicle collision speed for pedestrians and bikers), there was a significant higher difference for BAC positive patients (30 ± 20) compared to the BAC negative patients (25 ± 19, p < 0.0001). Alcohol intoxication in trauma patients leads to higher preclinical mortality, higher impact speed difference, and higher injury severity. The subgroup analysis for different alcohol concentrations shows no difference in ISS, MAIS, and relative speed, but a correlation of increasing age of patients with higher alcohol concentrations.

Comparative study of different intraoperative 3-D image intensifiers in orthopedic trauma care.

INTRODUCTION Recently, isocentric C-arm fluoroscopy (Iso-C 3D) has been introduced as a precise imaging modality for intraoperative evaluation and management of fractures and osteosyntheses. The Siemens Iso-C 3D collects multiple fluoroscopic images during a 190-degree arc of rotation around the anatomic region of interest and reconstructs them into sagittal, axial, and coronal planes. Like the Iso-C 3D, the new Ziehm Vario 3D imaging system reconstructs images in multiple planes, but only requires a 136-degree arc of rotation. The purpose of this study was to compare the image quality and range of applicability of these two imaging systems. METHODS All the tests were performed on a human cadaver. In the first part of the experiment, different bones and joints were scanned in their native condition using both the Iso-C 3D and Vario 3D. In the second part of the experiment, scans were performed in the same anatomic regions after simulated fractures and subsequent fixation. In some cases, suboptimal placement of hardware was intentionally undertaken. Direct visualization of the fracture construct and in certain cases computed tomographic (CT) imaging served as the gold standard. The scans from both imaging systems were analyzed using a DICOM viewer by five orthopedic trauma surgeons randomized and blinded to the study. The evaluation was based on the overall image quality, delineation of cancellous and cortical bone, delineation of joint surfaces, presence of artifacts, visualization quality of intra-articular incongruities, quality of reduction and implant positioning, and clinical applicability of the scan. These items were rated using a visual analog scale and a points system. A total of 55 3D scans were made and evaluated. RESULTS There was no significant difference between the two imaging systems in terms of the overall image quality, delineation of cancellous and cortical bone, and the presence of artifacts. The delineation of joint surfaces was significantly better visualized with the Iso-C 3D. Furthermore, Iso-C 3D scans demonstrated a higher overall clinical applicability than Vario 3D images. However, the Vario 3D was able to provide superior quality with scans of the shoulder joint and the adipose tissue. There was no significant difference in the visualization of intra-articular incongruities, quality of reduction, and implant positioning. CONCLUSION Although the Iso-C 3D imaging system was superior in delineating the joint surfaces, the image quality, and the overall clinical applicability, the study revealed that both devices provided 3D images with sufficient quality to the surgeon to assess clinically relevant questions, including the quality of fracture reduction and implant positioning. On the other hand, the Ziehm Vario 3D is capable of doing scans of the shoulder area, which could not be taken with the Siemens Iso-C 3D because of the isocentric design.

Use of a virtual 3D software for planning of tibial plateau fracture reconstruction.

OBJECTIVE Anatomical reconstruction of tibial plateau fractures is necessary to prevent pain, axial malalignment, knee join instability and posttraumatic arthritis. Computed tomography (CT) with 3D reconstruction is helpful in the accurate preoperative evaluation and reduction planning of the fracture site. The aim of this study was to describe the application of a virtual 3D reconstruction and segmentation software in the preoperative planning of tibial plateau fractures. PATIENTS AND METHODS CT scans of five tibial plateau fractures were preoperatively evaluated using the 3D planning software. Manual colour-coded segmentation was performed. The amount of time required for each planning session was recorded. RESULTS Successful 3D reconstruction and segmentation was achieved in all cases. The mean time required for 3D virtual planning was 174.8 min (range 69-124 min). The mean time required for 3D virtual planning of B-type fractures was 96.5 min (range 69-124 min; SD=38.891 min; CI=349.421). The mean time required for planning of C-type fractures was 227 min (range 167-294 min; SD=63.789 min; CI=158.460) (Table 1). CONCLUSION Successful segmentation was achieved in all cases. The 3D planning capabilities of this software may be a valuable tool for surgeons in learning about the nature of the injury in tibial plateau fracture cases and in formulating an appropriate surgical plan. However, the time requirement for the 3D reconstruction and segmentation analysis may be a current deterrent for its use in the clinical setting.

Tunnel Widening After Anterior Cruciate Ligament Reconstruction: An Experimental Study in Sheep

Background A common clinical concern after anterior cruciate ligament reconstruction is the expansion of the bone tunnels as seen radiographically. The etiology and clinical relevance of this phenomenon remain unclear. Hypothesis Tunnel widening results in an increased anteroposterior translation, and there are specific histologic changes due to osteoclastic bone resorption associated with this phenomenon. Study Design Controlled laboratory study. Methods Thirty sheep (age, 4 months) underwent an anterior cruciate ligament reconstruction using a soft tissue graft. Graft fixation was achieved using the EndoButton and Suture Washer. Six animals each were sacrificed at 0, 3, 6, 12, and 24 weeks after surgery. Each anterior cruciate ligament–reconstructed knee was examined by computed tomography. Anteroposterior translation was determined using a universal force-moment sensor robot. The bone surrounding the tunnel was evaluated histologically. Results The prevalence of tunnel enlargement on the femoral side was 77.3%. Animals with tunnel widening did not demonstrate increased anteroposterior translation. Widening of the femoral tunnel was significantly associated with a higher stiffness of the graft (P <. 05) and hypertrophy of the graft throughout the remodeling process. The histologic evaluation of the bone tunnel walls demonstrated an increase of bone volume in animals with tunnel enlargement. No statistically significant correlation could be found between the number of osteoclasts and the presence of tunnel widening. Conclusion In this large animal model of anterior cruciate ligament reconstruction, animals with significant tunnel widening did not suffer increased anteroposterior translation. Tunnel widening was associated with a high stiffness of the graft, graft hypertrophy, and an increase in bone volume of the tunnel wall. Clinical Relevance The present data correspond to the current opinion in humans that tunnel widening is not associated with knee instability. Further research is needed to understand the role of graft stiffness, graft hypertrophy, and the increase in bone volume in this phenomenon.

Utility of intraoperative three-dimensional imaging at the hip and knee joints with and without navigation.

Intraoperative three-dimensional imaging in orthopaedic trauma care has achieved greater importance over the last few years in some specialized hospital centers. For various types of peripheral-extremity trauma, clinical studies have confirmed, on the basis of three-dimensional information, an intraoperative revision rate ranging from 7% to 19%. Three-dimensional C-arm imaging may be used to achieve adequate intraoperative information about the quality of fracture reduction, residual steps, and correct implant placement, and this technique has been described for use in both the hip joint (for acetabular fractures, isolated femoral head [Pipkin-type] fractures, three-dimensional navigated sacroiliac screw or acetabular column screw placements, and, less frequently, for navigated drilling of tumors or osteochondral lesions) and the knee joint (for tibial plateau fractures, complex distal femoral condylar fractures, and navigated targeting of osteochondral lesions in combination with the use of preoperative magnetic resonance imaging scans). Major limitations of this technology include increased intraoperative time requirements, limited image quality compared with that of computed tomographic scans, cost, specific positioning techniques, and the need for radiolucent operating-room tables. Although prospective studies have yet to be conducted, the ways in which the surgeon will benefit from the use of intraoperative three-dimensional imaging are apparent, but indications for combined three-dimensional C-arm navigated procedures at the hip and knee joint are still limited. Future directions may include the use of digital flat-panel detectors and even robotic-controlled C-arm motion.

The Aseptic Femoral and Tibial Shaft Non-Union in Healthy Patients – An Analysis of the Health-Related Quality of Life and the Socioeconomic Outcome

Long bone non-unions may lead to recurrent surgical procedures and in-hospital stays. Thus, restrictions of the health-related quality of life and of socioeconomic parameters might be expected. Knowledge of the impact on several parameters of professional life is sparse. Therefore, we analyzed the outcome in patients following non-unions of the tibial and femoral shaft after fracture compared to patients with uneventful healing. Material and Methodology: 51 patients following non-unions of the the femoral (FNU) or tibial shaft (TNU) were compared to 51 patients (groups FH and TH) with uneventful fracture healing. Physical and mental health was assessed using the Short-Form Health Survey (SF-12), Hospital Anxiety and Depression Scale (HADS) and the Impact of Event Scale (IES). We also analyzed employment status and the usage of medical aids. Results: Scores of the SF-12 physical and psychological were lower in group TNU compared to group TH, the score of SF-12 physical but not psychological was significantly lower in group FNU compared to FH. Compared to uneventful healing, a significantly more frequent usage of medical aids was found in both non-union groups. A higher incidence of early retirement and unemployment was found in group FNU but not in group TNU. Conclusions: There is a profound influence on the quality of life following femoral or tibial non-unions after trauma. Compared to patients with uneventful fracture healing, patients with tibial and even more so femoral non-union show worse scores of the SF-12. Medical aids are frequently used following both, femoral and tibial non-unions. Not tibial, but femoral non-unions frequently lead to severe restrictions in professional life such as early retirement and unemployment.

Navigated minimally invasive thoracolumbar pedicle screw placement with flat panel 3-D imaging. A feasibility study

STUDY DESIGN The current study involves a cadaveric specimen with navigated pedicle screw placement using conventional reference markers and isocentric 3D fluoroscopy and also minimally invasive reference marker use with a flat panel 3D scanner. OBJECTIVE To test the feasibility of a novel minimally invasive reference marker system for navigated pedicle screw placement in combination the use of a new imaging modality i.e. flat panel 3D imaging. SUMMARY OF BACKGROUND DATA A major limiting factor of navigated pedicle screw placement is the requirement for intraosseous fixation of reference markers. This usually necessitates an open approach to the spinous process. To address this issue, the current authors have developed a minimally-invasive fixation device for spinal reference marker fixation. METHODS A fresh-frozen cadaver with no history of spinal injury or deformity was positioned prone on a radiolucent table. L3 and L4 vertebrae were randomly selected for conventional pedicle screw insertion while T5 and T6 were selected for the percutaneous technique. A flat detector 3D C-arm (Ziehm vision FD 3D; Ziehm, Nuremberg, Germany) was used to evaluate the position of the pedicle screws at the vertebral levels targeted in the study. RESULTS All screws placed within the lumbar spine involved conventional reference markers. The average depth deviation was 0.73 mm and the average axis deviation was 1.67 mm. Within the thoracic spine, the minimally-invasive marker fixation devices were used. The average depth deviation was 0.85 mm and the average axis deviation was 1.75 mm. In both cases, the plan and navigation were performed satisfactorily. The Y-jaw clamp for minimally-invasive reference fixation seemed to provide stable and robust fixation of the markers, requiring only two small incisions. CONCLUSIONS The minimally invasive reference marker system produced results which were comparable to the conventional intra-osseous markers while the flat detector-based navigation was shown to be easier to use and faster than isocentric Iso-3D technology.

Bicyclist–Bicyclist Crashes—A Medical and Technical Crash Analysis

Background: The purpose of this study was to analyze the actual injury situation of bicyclists focusing on accidents involving more than one bicyclist. A medical and technical analysis was performed as a basis for preventive measures. Methods: Technical and medical data were collected at the scene, shortly after the accident. Technical analysis included speed at crash, type of collision, impact angle, environment, lane used, and relative velocity. Medical analysis included injury patterns and severity (Abbreviated Injury Scale [AIS], Injury Severity Score [ISS]). Results: Five hundred seventy-eight injured bicyclists in 289 accidents from 1999 to 2008 were included into the study. Sixty-one percent were male (n = 350) and 39 percent were female (n = 228). Sixty-seven percent ranged between 18 and 64 years of age, 12 percent each between 13 and 17 years of age and older than 65 years, 8 percent between 6 and 12 years, and 1 percent between 2 and 5 years. Ninety-two percent of crashes took place in urban areas and 8 percent in rural areas. Ninety-seven percent of crashes occurred in dry conditions and 3 percent in wet conditions. Eighty-three percent of all accidents occurred during the daytime, 10 percent at night, and 7 percent at dawn. The helmet use rate was only 7.5 percent for all involved bicyclists. The mean Abbreviated Injury Scale (AIS) score was 1.31. Conclusion: The prevalence of bicycle-to-bicycle crashes is high. Most of these accidents occur in urban areas. Bicyclists should be considered as minimally or unprotected road users, with an unsatisfactorily low rate of helmet use. Though the average level and patterns of injuries is moderate, most of the severe injuries involved the head and extremities. However, there was no significant correlation between frequent helmet use and sustained injuries to the head of major AIS.

Vertebral fractures in motor vehicle accidents–a medical and technical analysis of 33,015 injured front-seat occupants

Spinal injuries pose a considerable risk to life and quality of life. In spite of improvements in active and passive safety of motor vehicles, car accidents are regarded as a major cause for vertebral fractures. The purpose of this study was to evaluate the current incidence of vertebral fractures among front-seat occupants in motor vehicle accidents, and to identify specific risk factors for sustaining vertebral fractures in motor vehicle accidents. Data from an accident research unit were accessed to collect collision details, preclinical data, and clinical data. We included all data on front-seat occupants. Hospital records were retrieved, and radiological images were evaluated. We analysed 33,015 front-seat occupants involved in motor vehicle accidents over a 24-year period. We identified 126 subjects (0.38%) with cervical spine fractures, 78 (0.24%) with thoracic fractures, and 99 (0.30%) with lumbar fractures. The mean relative collision speeds were 48, 39, and 40 kph in subjects with cervical, thoracic, and lumbar spine fractures, respectively, while it was 17.3 kph in the whole cohort. Contrary to the overall cohort, these patients typically sustained multiple hits rather than simple front collisions. Occupants with vertebral fractures frequently showed numerous concomitant injuries; for example, additional vertebral fractures. The incidence of vertebral fractures corresponded with collision speed. Safety belts were highly effective in the prevention of vertebral fractures. Apart from high speed, complex injury mechanisms as multiple collisions or rollovers were associated with vertebral fractures. Additional preventive measures should focus on these collision mechanisms.