Grit Rademacher

Blunt Liver Injuries in Polytrauma: Results from a Cohort Study with the Regular Use of Whole-body Helical Computed Tomography

The estimated prevalence of liver injury in patients with blunt multiple trauma ranges from 1% to 8%. The objective of this study was to investigate the profile of accompanying liver injury in a cohort of polytraumatized patients who had regularly undergone contrast-enhanced, whole-body helical computed tomography (CT). We enrolled consecutive patients admitted between September 1997 and January 2001 to a level I trauma center. Clinical baseline data were compiled as part of a nationwide trauma registry. Morphologic features were evaluated descriptively, whereas prognostic variables were assessed by logistic regression analysis. We identified 218 patients [149 men, mean age 35 ± 18 years, mean injury severity score (ISS) 35 ± 10], 55 of whom had sustained blunt liver trauma [25.2%, 95% confidence interval (CI) 19.6–31.5%]. The prevalence of Moore III to V lesions was 10.1%. There were 99 parenchymal contusions, 15 capsular tears, and 2 liver fractures. Surgery was required in 15 patients and was best predicted by the classification of the American Association for the Surgery of Trauma [odds ratio (OR) 3.91, 95% CI 1.59–9.61]. The mortality rate was 0.0035/person/day. Patients requiring surgical repair had fourfold increased relative odds of case fatality (OR 4.50, 95% CI 1.01–19.96). Sevenfold increased relative odds were observed if liver laceration was considered the leading injury (OR 7.17, 95% CI 1.17–43.97). The prevalence of liver lacerations among multiple-trauma patients is likely to be underestimated and must be determined by the independent application of reference standards, such as helical CT. High-grade hepatic injuries and the need for surgical repair are associated with poorer survival prognosis.

Accuracy of single-pass whole-body computed tomography for detection of injuries in patients with major blunt trauma

Background: Contrast-enhanced whole-body computed tomography (also called “pan-scanning”) is considered to be a conclusive diagnostic tool for major trauma. We sought to determine the accuracy of this method, focusing on the reliability of negative results. Methods: Between July 2006 and December 2008, a total of 982 patients with suspected severe injuries underwent single-pass pan-scanning at a metropolitan trauma centre. The findings of the scan were independently evaluated by two reviewers who analyzed the injuries to five body regions and compared the results to a synopsis of hospital charts, subsequent imaging and interventional procedures. We calculated the sensitivity and specificity of the pan-scan for each body region, and we assessed the residual risk of missed injuries that required surgery or critical care. Results: A total of 1756 injuries were detected in the 982 patients scanned. Of these, 360 patients had an Injury Severity Score greater than 15. The median length of follow-up was 39 (interquartile range 7–490) days, and 474 patients underwent a definitive reference test. The sensitivity of the initial pan-scan was 84.6% for head and neck injuries, 79.6% for facial injuries, 86.7% for thoracic injuries, 85.7% for abdominal injuries and 86.2% for pelvic injuries. Specificity was 98.9% for head and neck injuries, 99.1% for facial injuries, 98.9% for thoracic injuries, 97.5% for abdominal injuries and 99.8% for pelvic injuries. In total, 62 patients had 70 missed injuries, indicating a residual risk of 6.3% (95% confidence interval 4.9%–8.0%). Interpretation: We found that the positive results of trauma pan-scans are conclusive but negative results require subsequent confirmation. The pan-scan algorithms reduce, but do not eliminate, the risk of missed injuries, and they should not replace close monitoring and clinical follow-up of patients with major trauma.

MRI Artifacts and Cochlear Implant Positioning at 3 T In Vivo.

Hypothesis To evaluate the assessment of the internal auditory canal and the labyrinth in relation to different CI magnet positions and MRI sequences at 3 T. Background The indication criteria for cochlear implantation have been changed over the years and the growing number of implantations in patients after acoustic neuroma resections underline the importance of a postoperative MR imaging to assess the internal auditory canal (IAC) and the labyrinth. The MRI artifact induced by the cochlear implant magnet is a known problem that should be further observed by this investigation. Methods We compared the artifacts of Cochlear 512 magnets at different head positions in vivo at 3 T. The observed positions varied with a nasion-external ear canal angle of 90, 120, and 160 degrees and a variable distance of 5, 7, and 9 cm in relation to the external ear canal and different MRI sequences. Results The complete assessment of the internal auditory canal and labyrinth was possible with a magnet positioned at 90 degrees and 9 cm and 160 degrees and 9 cm. Evaluation of the IAC alone was possible with magnet positions at 90 degrees and 7 cm and 9 cm, 120 degrees and 9 cm, and 160 degrees and 7 cm and 9 cm. A high-resolution 3D T2w Drive sequence decreased the visibility of the structures significantly. A high-resolution TSE 2D T2w sequence together with one of the above-described positions allowed sufficient visualization of the structures. Conclusion The position of the implant and the MRI sequence used determine the assessment of the IAC and the labyrinth at 3 T MRI. A position of the implant magnet at a nasion-external auditory canal angle which is more horizontal and posterior than so far commonly used allows a better visualization of the IAC and the labyrinth at 3 T.

Optimization of Contrast Agent Volume for Helical Ct in the Diagnostic Assessment of Patients with Severe and Multiple Injuries

Purpose The aim of this study was to determine the optimal amount of contrast agent for helical CT of the trunk during primary radiologic evaluation of polytraumatized patients. Method Eighty-three patients with severe and multiple injuries (mean age 36.2 years) underwent standardized helical CT examination with administration of a single contrast agent bolus of iohexol (Accupaque 300) at volumes of 120, 150, and 180 ml. Image quality was estimated by two blinded radiologists using a visual analogue scale. Analysis further included density measurements in regions of interest (ROIs) placed in the ascending, descending, and abdominal aorta as well as in the liver and spleen. Results The qualitative rating of the contrast agent effect after administration of 150 and 180 ml was significantly better compared with 120 ml [odds ratio (OR) 12.05, 95% confidence interval (CI) 3.50–41.52 and OR 12.14, 95% CI 3.36–43.85, respectively]. A dose increase from 120 to 150 ml resulted in a significantly better enhancement of the abdominal aorta (p = 0.006). The highest dose of 180 ml was not associated with a diagnostic gain in the other ROIs. Conclusion We recommend administration of 150 ml of iohexol as the optimal amount of contrast material for single phase bolus administration in emergency helical CT examination of the chest and abdomen.

Evaluation of cochlear implant electrode position after a modified round window insertion by means of a 64-multislice CT

Conclusion. The modified round window insertion enables reproducible insertion into the scala tympani as demonstrated by comparing the 64-CT scanning data and the surgeons reports. Objective. To estimate the postoperative cochlear implant electrode position using a modified round window approach. Patients and methods. In a prospective study, 82 patients were operated via a modified round window approach to insert primarily into the scala tympani. Surgery had been performed from 2005 to 2008, implanting a Nucleus Freedom RECA device (Cochlear Corp.) (n=43) or 90 k Helix device (Advanced Bionics Corp.) (n=39). The array localization within the cochlea was determined by axial scanning overview, digital reconstruction of a 64-slice CT and by evaluation of the surgeons report. Results. In 78 (95.1%) patients, the array could be located in the scala tympani. In four cases, the position of the electrode was changed intracochlearly from the scala tympani to the scala vestibuli. In three additional cases, the scala vestibuli was inserted intentionally because the tympanic scale was found to be obstructed intraoperatively due to ossification. There were no significant differences between the intraoperative positioning and postoperative localization of the electrode arrays of the two manufacturers.

Resorbable screws versus pins for optimal transplant fixation (SPOT) in anterior cruciate ligament replacement with autologous hamstring grafts: rationale and design of a randomized, controlled, patient and investigator blinded trial [ISRCTN17384369]

BackgroundRuptures of the anterior cruciate ligament (ACL) are common injuries to the knee joint. Arthroscopic ACL replacement by autologous tendon grafts has established itself as a standard of care.Data from both experimental and observational studies suggest that surgical reconstruction does not fully restore knee stability. Persisting anterior laxity may lead to recurrent episodes of giving-way and cartilage damage. This might at least in part depend on the method of graft fixation in the bony tunnels. Whereas resorbable screws are easy to handle, pins may better preserve graft tension. The objective of this study is to determine whether pinning of ACL grafts reduces residual anterior laxity six months after surgery as compared to screw fixation.Design/ MethodsSPOT is a randomised, controlled, patient and investigator blinded trial conducted at a single academic institution. Eligible patients are scheduled to arthroscopic ACL repair with triple-stranded hamstring grafts, conducted by a single, experienced surgeon. Intraoperatively, subjects willing to engage in this study will be randomised to transplant tethering with either resorbable screws or resorbable pins. No other changes apply to locally established treatment protocols. Patients and clinical investigators will remain blinded to the assigned fixation method until the six-month follow-up examination.The primary outcome is the side-to-side (repaired to healthy knee) difference in anterior translation as measured by the KT-1000 arthrometer at a defined load (89 N) six months after surgery. A sample size of 54 patients will yield a power of 80% to detect a difference of 1.0 mm ± standard deviation 1.2 mm at a two-sided alpha of 5% with a t-test for independent samples.Secondary outcomes (generic and disease-specific measures of quality of life, magnetic resonance imaging morphology of transplants and devices) will be handled in an exploratory fashion.ConclusionSPOT aims at showing a reduction in anterior knee laxity after fixing ACL grafts by pins compared to screws.

Functional outcomes and health-related quality of life after robot-assisted anterior cruciate ligament reconstruction with patellar tendon grafts

During a short period of time, surgical robots had been propagated for automated tunnel placement in anterior cruciate ligament (ACL) reconstruction. Clinical outcome data are currently unavailable. Between 2000 and 2003, 152 patients underwent ACL replacement with the assistance of the Computer Assisted Surgical Planning and Robotics system (CASPAR, OrtoMaquet, Germany) at our hospital. After minimal invasive pin placement in both the tibia and femur, computed tomography was used to register anatomical landmarks and to plan graft tunnel alignment. The robot was used to drill tibial and femoral tunnels in an outside-in fashion according to pre-operative planning. There was one procedure-specific Serious Adverse Event (i.e., an intraoperative transection of the posterior cruciate ligament). After IRB approval, all patients were invited for a follow-up examination. Data from 100 patients (35 women, 65 men, mean age 35 [SD 11] years, median follow-up 61 [range 42–77] months) form the basis of this report. Side-to-side differences in anterior laxity were measured with the KT-1000 arthrometer. Patient-centered outcomes included the Lysholm-Score, the lower extremity functional scale (LEFS), and the Short Form 36 (SF36). The mean KT-1000 side-to-side difference was 0.89 [95% confidence interval (CI) 0.52–1.26] mm. Eight and five patients had a positive Lachman and pivot shift test, respectively. The Lysholm-Score averaged 86 (95% CI 83–89) points. Excellent, good, fair, and poor outcomes were reported by 38, 32, 20, and 10 patients. The LEFS averaged 85 (95% CI 82–88) points. The mean SF36 Physical Component Score was 48.4 (95% CI 46.5–50.3), indicating residual deficits compared to the population norm. All tibial graft tunnels did not cross the Blumensaat line, but were placed slightly anterior to the optimal center of 42% reported in previous studies. Compared to literature data, robot-assisted ACL reconstruction with BTB grafts may lead to higher knee stability, but poorer functional outcomes. The immense additional efforts with the procedure did not pay off in a benefit to patients.

Predictive factors of liver injury in blunt multiple trauma

IntroductionThis study was conducted to clarify whether injuries that are likely to be revealed by initial clinical and conventional radiological examination at the trauma bay (e.g., right-side rib fractures) meaningfully contribute to the prior probability of accompanying hepatic lesions in multiple injured patients.Material and methodsFifty-five subjects (sampled from a cohort of 218 patients) with liver injury fulfilling the definition of polytrauma were compared with 55 polytrauma patients without liver injury. Controls were individually matched for age, gender, and Injury Severity Scores. Whole-body, helical, contrast-enhanced computed tomography was applied to all participants. We modeled independent predictors of liver involvement by conditional logistic and random-effects regression analysis.ResultsIn the present sample, the prevalence of hepatic injury was 25.2%. Neither the injury mechanism (car crash, pedestrian accident, fall from height) nor certain accompanying injuries (right-side serial rib fractures, lumbar spine fractures) predicted the presence of hepatic injury. Liver injury was particularly unlikely in bikers [odds ratio (OR) 0.78, 95% confidence interval (CI) 0.59–1.03] and patients with left-side rib fractures (OR 0.80, 95% CI 0.66–0.98).DiscussionThere are no index injuries that will reliably indicate the presence of liver involvement in multiple trauma cases. Also, the absence of these injuries cannot rule out liver damage.

Neurotological and Neuroanatomical Changes in the Connexin-26-Related HID/KID Syndrome

The phenotype of the HID (hystrix-like ichthyosis, deafness)/KID (keratitis, ichthyosis, deafness) syndrome is primarily characterized by skin changes. However, the connexin 26 (Cx 26) autosomal dominant mutation underlying this syndrome is of special neurotological interest. In the present paper, the clinical pattern, audiovestibular and neuroimaging findings and the detailed genetic analysis of 4 patients with identical HID/KID-associated mutation D50N of Cx 26 are reported. The audiological test results demonstrated profound sensorineural hearing loss in all of the patients. Neurotological testing revealed inconsistent abnormalities in dynamic posturography (sensory organization test), but the vestibular ocular reflex upon caloric irrigation was normal in all patients. Vestibular-evoked myogenic potential testing for otolith function (saccule) showed a regular response in 1 patient and pathologic responses in 3 patients, while subjective haptic vertical (utricular function) testing was normal in all of the patients. CCT showed an extended (in length), but very thin (in diameter) bony lining between the basal portion of the internal auditory canal and the vestibule in the 3 scanned patients. Our study provides evidence for functionally intact semicircular canals and normal utricular function in subjects with the autosomal dominant D50N mutation of Cx 26, in contrast to saccular function which was generally compromised and hearing loss which was profound.

Evaluation of the Relationship between the NRT-Ratio, Cochlear Anatomy, and Insertions Depth of Perimodiolar Cochlear Implant Electrodes

The position of the cochlear implant electrode array within the scala tympani is essential for an optimal postoperative hearing benefit. If the electrode array changes in between the scalae intracochlearly (i.e., from scala tympani to scala vestibuli), a reduced auditory performance can be assumed. We established a neural response telemetry-ratio (NRT-ratio) which corresponds with the scalar position of the electrodes but shows within its limits a variability. The aim of this study was to determine if insertion depth angle or cochlea size influences the NRT-ratio. The intraoperative electrophysiological NRT data of 26 patients were evaluated. Using a flat panel tomography system, the position of the electrode array was evaluated radiologically. The insertion depth angle of the electrode, the cochlea size, and the NRT-ratio were calculated postoperatively. The radiological results were compared with the intraoperatively obtained electrophysiological data (NRT-ratio) and statistically evaluated. In all patients the NRT-ratio, the insertion depth angle, and the cochlea size could be determined. A significant correlation between insertional depth, cochlear size, and the NRT-ratio was not found. The NRT-ratio is a reliable electrophysiological tool to determine the scalar position of a perimodiolar electrode array. The NRT-ratio can be applied independent from insertion depth and cochlear size.