In orthopaedic surgery, as in many other surgical fields, there is a clear tendency towards the use of minimally invasive procedures. These techniques are increasingly being implemented almost routinely for procedures such as spine and pelvis surgery. However, for fracture treatment and for applications involving small bones, such as hand and foot surgery, these systems are hardly ever used. We introduce a new system for image based guidance in traumatology.

We included 20 patients with a fracture of the fifth metatarsal. They were randomised on admission into two groups. Ten patients in the metatarsal group were operated conventionally and ten were operated with the assistance of a new image guidance system. This system is based on 2D-fluoro images which are acquired with a conventional c-arm and are transferred to the system workstation. After detecting marked tools, it can be used to display trajectories for K-wire guidance in the c-arm shot.

The average duration of surgery (time from incision to suture) in the image-based group was 12.7 minutes ± 5.5 (min. 6, max. 23), in the conventional group it was 17 minutes ± 6.5 (min. 7, max. 28) (p=0.086). The average duration of radiation was 18 seconds ± 8.5 (min. 6, max 36) in the image-based group vs. 32.4 seconds ± 19.4 (min. 12, max. 66) in the conventional group (p=0.057). An average of 4.7 C-arm shots ± 2 (min 2, max 9) were necessary in the image-based group to position the K-wire. For the conventional group, 8.2 shots ± 2.3 (min 4, max 12) were used (p=0.0073). It took 1.6 trials ± 0.7 (min.1, max. 3) to position the K-wire for the image-based procedures, in the conventional group 2.7 trials ± 0.9 (min. 1, max 4) were necessary (p=0.0084). There were no malfunctions or adverse events in any of the image-based navigational cases. No screws needed to be replaced in the image-based group. In the conventional group, two screws were replaced intra-operatively because they were too short in the control c-arm shot, and the screw threads did not bridge the fracture gap completely, leading to insufficient compression.

In this pilot study with only a small sample size, the image-based guidance system could be integrated into the existing surgical workflow and was used for applications, where existing navigation systems are not commonly used. The technology gives the surgeon additional information and can reduce the number of trials for perfect implant positioning. This potentially increases the safety of the surgical procedure and spares intact bone substance which is essential for the footing of implants in small bones and fragment fixation. Whether these factors contribute to a reduction in complications or revision rate must be confirmed in larger prospective studies.

Introduction: After whiplash injuries the majority of patients complain of pain, muscular dysfunctions and restricted movement of the cervical spine, however, the cause of these symptoms cannot be diagnosed.

Against this background, the hypothesis is formulated that functional disturbances in the form of pathological activities of the neck muscles occur as a result of a whiplash injury of the cervical spine. These pathological muscle activities can be demonstrated electromyographically and differ from the patterns of activity of healthy subjects.

Study Objective: Thus, the aim of this study was to establish an electromyographical method for the diagnosis of functional disturbances of the neck muscles after whiplash injuries of the cervical spine.

Material/Method: Primarily, an intramuscular recording of the electromyographical activity of the semispinalis capitis muscle was performed during flexion/extension and axial rotation in 46 patients with chronic symptoms after a whiplash injury of the cervical spine (QTF grade II) and 29 healthy subjects. The movement was controlled with techniques of virtual reality. The subject is immersed into a virtual outer space environment with a head-mounted display (HMD). In this virtual scene, the patient follows paths of motion of a signal (globe) with his/her gaze.

A subsequent study was conducted to validate the results that had been obtained. For this purpose, the electromyographical activity of the semispinalis capitis muscle was recorded in another subject group (n=20) and patients with acute symptoms as a result of a whiplash injury of the cervical spine (QTF grade II) (n=35).

Results: Compared to the physiological muscle activities that were established in the first subject group, changes could be observed in the chronic patient group.

Subjects in our study, for instance, show a decrease in electrical activity during flexion and the resulting stretching of the semispinalis capitis muscle, while the same movement causes an increase in activity in patients. On the basis of these differences, 93 % of subjects (specificity) and 83 % of patients (sensitivity) could be classified correctly with a discriminance analysis.

In the second study, the specificity was 88 % while a sensitivity of 86 % was determined in the acute patient population.

Conclusion: The results of these investigations enable a highly specific and sensitive diagnosis of muscular dysfunctions on the basis of the intramuscular recordings of the electromyographical patterns of activity of the semispinalis capitis muscle.

Background: In a car-to-car collision, an adequate force has to be exerted to produce an injury of the cervical spine. This force is often described with the parameter delta-V. Limits for delta-V were defined for rear-end, frontal and side collisions on the basis of dummy experiments and volunteer crash tests under laboratory conditions, and then transformed for the road accident situation. According to this definition, an injury in a rear-end or side collision is unlikely at delta-V< 10km/h and probable at delta-V> 15km/h. For frontal collisions, the values are 20 km/h and 30km/h. To this day, there is no data to confirm these limits in the actual road accident situation.

Objective: Our objective was to compare clinical data and data from accident analyses of individuals after actual car-to-car collisions in a prospective study. We intended to check the validity of the delta-V limits on the basis of this data.

Methods: 57 individuals (25 males/32 females) were included in the study. The delta-V was calculated by a technical expert on the basis of photographs of the two cars involved. The individuals who had been in an accident were evaluated with regard to their history. Those reporting symptoms underwent a radiological and clinical examination.

Results: Rear-end collisions (n=21): The median delta-V for rear-end collisions is 13 km/h (min=3 km/h; max=58 km/h). 7 individuals reported symptoms. Both patients had delta-V values< 9km/h. Delta–V 10km/h.

Frontal collisions (n=13): The median delta-V for frontal collisions is 24 km/h (min=8 km/h; max=50 km/h). 4 individuals reported symptoms. Under delta-V 20, one individual had a fractured cervical vertebra (QTF IV).

Conclusions: The existing limits for delta-V cannot be transferred without reservation from the laboratory test situation to the actual road accident situation. Injuries and even fractures of the cervical spine can occur at a delta-V < 10km/h, particularly with side collisions. At the same time, delta-V values > 15km/h do not necessarily result in an injury of the cervical spine.