Outcome-related co-factors in 105 cases of vertebral osteomyelitis in a tertiary care hospital.

PURPOSE: Vertebral osteomyelitis (VO) is an infection of the vertebral body and the adjacent disc space. The aim of our study was to identify outcome-related co-factors of patients with VO treated in the last decade. METHODS AND RESULTS: We retrospectively identified 105 patients with VO (mean age 66.1 years) who had been treated at our institution from 2004 to 2011. The median time of hospitalization at our institution was 31.5 days, and 44 patients required intensive medical care. Back pain and fever were documented in 66.7 and 33.3 % of cases, respectively. The radiologic diagnosis of VO was made in 94.8 % of all obtained magnetic resonance imaging scans and in 66.2 % of all computed tomography (CT) scans. Biopsies were taken in 71 patients, and the causative organisms were identified in 56.2 % of patients, with Staphylococcus aureus being the predominant pathogen. Fifty-six patients underwent surgical treatment. During hospitalization, infectious complications were observed in 63 patients (60.0 %). The most common complications were psoas, paravertebral and epidural abscesses. Patients with S. aureus infections had a significantly higher rate of infectious complications than those without (76.5 vs. 40.3 %, respectively), and were more frequently treated in intensive care units (58.8 vs. 34.7 %, respectively). Overall in-hospital mortality rate was 12.4 %. Elevated C-reactive protein levels at admission, advanced age and a Charlson Comorbidity Index of ≥2 were associated with higher mortality. CONCLUSIONS: Magnetic resonance imaging currently is the imaging procedure of choice for the radiologic diagnosis of VO. Mortality is attributable in part to co-morbidities. However, infections with S. aureus are frequent in this patient population and are associated with a higher rate of complications and a trend towards higher mortality.

[Quad driving--life-endangering fun? A medical and technical analysis]. / Quad-Fahren--ein lebensgefährlicher Spaß? Eine medizinische und technische Unfallanalyse.

AIM: Quads or all-terrain vehicles do not seem to play a major role either in traffic accidents or in hospital admissions in Germany. However, reports about spectacular quad crashes in the press are not that infrequent. In contrast, no scientific survey or study regarding the issue of quad crashes in Germany has been published so far. Thus, this study aims to evaluate the present incidence of quad crashes, accident circumstances and resulting injury patterns, and to discuss possible consequences. METHOD: At a level I trauma centre, data from accident and hospital records of quad drivers were analysed focusing on the following parameters: injury type, localisation and mechanism, treatment details, abbreviated injury scale (AIS) score, maximum AIS (MAIS) score, delta-v, collision speed, and other technical parameters. Comparisons to motorcycle accidents were performed. RESULT During a five-year period from 2005 to 2009, there were ten admissions of quad drivers out of around 11 000 emergency trauma patients (0.1 %). Five accidents had happened off-road, four were traffic accidents. Eight patients were male; the mean age was 30 years. The mean total hospital stay was 15 days; there was a mean of 1.5 stays per patients with 2.0 surgical procedures needed. One patient died, only two recovered fully. The accident research data bank revealed 14 cases of quad accidents out of 18 990 (0.1 %). The mean impact velocity was 35 km/h (motorcyclists 40.0 km/h). The most frequent injury mechanism was a collision with a car. The upper extremity was the predominant injured region (AIS 0.7), while it was the lower extremity for motorcyclists (AIS0.91). The maximum AIS were 1.4 in quad drivers and 1.49 in motorcyclists. CONCLUSIONS: Although the absolute incidence of quad accidents in Germany is low, they pose a relatively high risk for severe injuries. Possible reasons are the comparatively low active and passive safety of quads as well as limited experience with quad driving and the "fun" aspect which might provoke risky driving behaviour. Larger series from the US report a high incidence of drug abuse among quad casualties as well as very limited use of helmets. In Germany, helmet usage has been mandatory since 2006. Possible additional measures to prevent a rise in quad accidents could be the total prohibition of alcohol consumption for quad drivers as well as special courses or driving licenses or an increase of the legal age for driving quads.

Development of a fixation device for robot assisted fracture reduction of femoral shaft fractures: a biomechanical study.

Robot assisted fracture reduction of femoral shaft fractures provides precise alignment while reducing the amount of intraoperative imaging. The connection between the robot and the fracture fragment should allow conventional intramedullary nailing, be minimally invasive and provide interim fracture stability. In our study we tested three different reduction tools: a conventional External Fixator, a Reposition-Plate and a Three-Point-Device with two variations (a 40 degrees and a 90 degrees version). We measured relative movements between the tools and the bone fragments in all translation and rotation planes. The Three-Point-Device 90 degrees showed the smallest average relative displacement and was the only device able to withstand the maximum applied load of 70 Nm without failure of any bone fragment. The Three-Point-Device 90 degrees complies with all the stipulated requirements and is a suitable interface for robot assisted fracture reduction of femoral shaft fractures.

Comparative biomechanical analysis of two techniques of radiolunate fusion: Shapiro staples vs. plate and oblique screw.

The purpose of this prospective randomized comparative biomechanical study on six pairs of human cadaveric forearms was to study the mechanism of implant loosening and loss of lunate positioning and to discern whether primary stability following staple arthrodesis differs from plate fixation. Six wrists were randomly assigned to either group such that one wrist of each pair was fixed via titanium staples and the other via a mini-titanium plate with oblique screw. Under fluoroscopic guidance, passive extension and flexion of each wrist was performed using a spring balance. Traction force increased by 5 N at each step, ranging from 0 N to a maximum of 100 N. Fixation using a plate and oblique screw demonstrated greater flexibility than staple fixation. Loosening of the implant and/or the lunate occurred earlier following staple fixation in all pairs. Osteolytic rims around the staple limbs within the lunate occurred in all wrists. These were observed to be an early sign of implant loosening and fusion failure. The current investigators conclude that radiolunate fusion via miniplate and oblique screw is superior to staple fixation in terms of primary stability which is consistent with the radiological results of comparable clinical trails.

First clinical experience with a novel forearm boom.

The optimal forearm boom should facilitate dynamic investigation of the wrist and approaches for wrist arthroscopy. It should be safely fixed at the operating table without any contact with the patient. It must be compatible with the arm of any patient and should be sterilisable. Repositioning of distal radius fractures, fluoroscopy and insertion of Kirschner-wires should not be restricted. According to these criteria the current investigators designed a new forearm boom which was subsequently used in 19 wrist arthroscopies and 9 distal radius fracture fixations. Twenty-eight patients with heights between 150 and 205 cm and forearm lengths between 17.5 to 37 cm were treated. Preoperatively, wrist motion was tested in those 19 wrists, that underwent wrist arthroscopy, before and after fixation by the forearm boom and any restriction due to usage of the novel device was found. The new forearm boom satisfied all of the criteria cited above. Therefore the current authors believe the new forearm boom may be valuable for the indications mentioned.

Computer-assisted antetorsion control prevents malrotation in femoral nailing: an experimental study and preliminary clinical case series.

MATERIALS AND METHODS: The effect of fluoroscopy-based navigation for femoral fracture reduction on the prevention of malrotation was examined in an experimental setting followed by a first case series. Eleven cadaver femurs were used. All femurs were reduced by closed methods. An optoelectronic navigation system was utilized to check for fragment reduction and alignment. Fluoroscopic control without navigation was used as the control group. The Six Sigma Analysis [offset capability index (C (pk)) = 1.3] was used to compare the probability of outliers of more than 15 degrees . In the clinical case series the same navigation tool was used in ten non-consecutive patients with femoral fractures. Torsional differences between both legs were measured postoperatively by CT scan. RESULTS: The highest malrotation in the navigated group was 7.0 degrees for the cadaver testings, while two femurs in the control group showed a difference of more than 10 degrees (10.3 degrees , 17.4 degrees). Only the navigated group showed a sufficient offset capability index (C (pk-navigated) = 1.83; C (pk-conventional) = 0.59). In the clinical series nine femurs were successfully reduced by navigation control. The average malrotation was 6.6 degrees . No patient had a torsional difference of more than 10 degrees. CONCLUSION: Navigated femoral nailing reduces the risk for outliers of postoperative torsional differences and might avoid revision surgery for malrotation. LEVEL OF EVIDENCE: IV.

[Accidental abdominal needlestick injury incurred while discarding a disposal container]. / Akzidentelle abdominelle Nadelstichverletzung bei der Entsorgung eines Abwurfcontainers.

Needlestick injuries routinely occur in everyday clinical practice. Adequate instruction of employees in health care and correct prophylaxis against exposure could conspicuously reduce the incidence. Successful prevention of chronic infectious diseases comprises strict vaccination plans and substantial knowledge of post-exposure prophylaxis. The introduction of self-securing cannulas and injection instruments represents an important technological advance.

[Femoral nail osteosynthesis. Mechanical factors influencing the femoral antetorsion]. / Mechanische Einflussfaktoren der Marknagelung auf die femorale Antetorsion. Optobiomechanische Messungen.

INTRODUCTION: Antegrade or retrograde intramedullary nailing is a common and well established procedure for the treatment of femoral shaft fractures. One drawback of this technique is the high incidence of clinically relevant malalignment. Despite intra-operative and radiological improvements this problem has not yet been solved efficiently. The aim of this study was the evaluation of the mechanical influence on the antetorsion angle of intramedullary nails during and after interlocking in femoral shaft fractures. MATERIAL AND METHODS: A mechanical instrument was developed allowing a defined torque to be administered to the distal femur fragment. As an optical measurement system for the assessment of the antetorsion angle, a navigation system was applied. Initially the influence of the interlocking mechanism of the nail on the antetorsion deviation was investigated. The distal interlocking hole was fixed free handed or by using a navigation system. The multidirectional movement of the distal femur fragment was documented. Furthermore, the influence of the rotational stability on the antetorsion angle after mechanical stress of 4 NM was investigated by measuring the remaining rotational capacity of the distal femur fragment. RESULTS: The average remaining rotational capacity of the distal femur fragment was 5.8 degrees after locking the nail by hand. The navigated locking resulted in a deviation of only 2 degrees , a significant difference compared to the free-hand procedure. The rotational stability under stress showed an average of 15.4 degrees deviation of the distal fragment. Even after complete interlocking of the intramedullary nail a 14.2 degrees rotational deviation was observed. DISCUSSION: It could be shown that mechanical stability as well as the interlocking itself of femoral nails have a relevant impact on the antetorsional angle of the femur. Potential sources of error of the femoral antetorsion angle can be caused by the interlocking process as well as by forced rotation of the femur after interlocking. Clinical studies are needed to improve our findings, while the observed effects might have an essential influence on the incidence of femoral malalignment after osteosynthesis by intramedullary nailing of the femur.

Accuracy of navigated surgery of the pelvis after surface matching with an a-mode ultrasound probe.

Computer-aided surgery (CAS) allows for real-time intraoperative feedback resulting in increased accuracy, while reducing intraoperative radiation. CAS is especially useful for the treatment of certain pelvic ring fractures, which necessitate the precise placement of screws. Flouroscopy-based CAS modules have been developed for many orthopedic applications. The integration of the isocentric flouroscope even enables navigation using intraoperatively acquired three-dimensional (3D) data, though the scan volume and imaging quality are limited. Complicated and comprehensive pathologies in regions like the pelvis can necessitate a CT-based navigation system because of its larger field of view. To be accurate, the patient's anatomy must be registered and matched with the virtual object (CT data). The actual precision within the region of interest depends on the area of the bone where surface matching is performed. Conventional surface matching with a solid pointer requires extensive soft tissue dissection. This contradicts the primary purpose of CAS as a minimally invasive alternative to conventional surgical techniques. We therefore integrated an a-mode ultrasound pointer into the process of surface matching for pelvic surgery and compared it to the conventional method. Accuracy measurements were made in two pelvic models: a foam model submerged in water and one with attached porcine muscle tissue. Three different tissue depths were selected based on CT scans of 30 human pelves. The ultrasound pointer allowed for registration of virtually any point on the pelvis. This method of surface matching could be successfully integrated into CAS of the pelvis.

[A-mode ultrasonic pointer for navigated pelvic surgery]. / A-Mode-Ultraschall-Pointer für die navigierte Beckenchirurgie.

Surgical navigation has proven to be a minimally invasive procedure that enables precise surgical interventions with reduced exposure to irradiation for patient and personnel. Fluoroscopy-based modules have prevailed on the market. For certain operations of the pelvis computed tomography is necessary with its high imaging quality and considerably larger scan volume. To enable navigation in these cases, matching of the CT data set and the patient's real pelvic bone is essential. The common pair point-matching algorithm is complemented by the surface-matching algorithm to achieve an even higher overall precision of the system. For conventional surface matching with a solid pointer, the bone has to be exposed from soft tissue quite extensively, using a solid pointer. This conflicts with the claim of computer-assisted surgery to be minimally invasive. We integrated an A-mode ultrasonic pointer with the intention to perform extended surface matching on the pelvic bone noninvasively. Related to the conventional method, comparable and to some extent even improved precision conditions could be established.