Multidetector computed tomography of spinal and pelvic fractures : with special reference to polytrauma patients

Serious injuries of the spine and pelvis are common in level I trauma centers, and are usually the result of high-energy accidents such as motor vehicle accidents (MVA) or falls from a height, but increasingly also sports and recreational accidents. Even presumably minor accidents can result in serious injury depending on the injury mechanism. The risk of acquiring a fracture is also tied to possible predisposing factors such as a weakened bone structure in osteoporosis, or an increased stiffness of the spine in ankylosing spondylitis. ----- Spinal injuries have a potential for catastrophic, life-altering consequences, because they are associated with spinal cord injury (SCI). A missed or inappropriately managed spinal injury can result in secondary SCI or progression of the initial damage. But also pelvic fractures pose a serious threat, as there are large-caliber blood vessels, nerves, and the lower urinary tract in close proximity to the pelvic bones. An acute bleeding into the pelvic area can remain clinically silent for an extended amount of time due to circulatory compensation processes. Exclusion of these occult injuries by imaging techniques is therefore imperative in order to detect a serious injury as early as possible and administer appropriate treatment. Time-, space-, and cost restraints as well as the patient s stability limit the application of imaging modalities in the golden hour of trauma resuscitation, which is arguably the most critical phase for the patient s outcome. The optimal choice of imaging methods is therefore crucial. But also the knowledge of injury patterns and demographic risk factors contributes to the correct diagnosis of a serious injury. This thesis focuses on injury patterns of the spine in conjunction with high-energy accidents, as well as demographic patterns and the optimal choice of imaging modality. It consists of five publications with a total of 2375 patients, covering a time frame from January 2001 to September 2009. There is special emphasis on vertebral burst fracture, which is the most common fracture in the thoracolumbar area, and which has furthermore a high potential for SCI due to its unstable nature. Also the bony pelvis as an extension of the spine receives special reference. According to our results, serious spinal injury as a result of blunt trauma occurs in all age groups and independently of gender, and even minor trauma energies can result in serious trauma. Trauma energy does have an influence though, as the incidence of spine fractures increases with increasing falling height, and burst fractures and spine fractures on multiple levels become more frequent. But also other blunt trauma mechanisms had multiple spine fractures in up to 32 % of cases, whereof 29 % were non-contiguous. Burst fracture was seen on multiple levels in 10 % of cases, with 50 % being non-contiguous. The frequent occurrence of vertebral fractures and especially burst fractures on non-contiguous levels makes imaging of the whole spine necessary in conjunction with high-energy accidents, especially in obtunded patients. Radiography demonstrates unstable vertebral fractures with acceptable accuracy, particularly in the lumbar spine (LS). Summation of overlapping tissue in these areas makes the identification of the hall marks of an unstable facture difficult, which can lead to an injury being missed, or wrongly classified as stable. Neurological deficit was most frequent and serious in the CS. In the pelvic area, radiography detected only 55 % of fractures diagnosed by multidetector computed tomography (MDCT), and in 11 % findings were false negatively normal. Additionally, Tile classification of fractures was correct in 59 % of injuries, whereas the subtype was correct in only 14 %. The pelvis was false negatively classified as stable in 40 % of cases. Sport and recreational accidents had an overall incidence of injury of one in five, of which 71 % were considered to be serious. The three most common types of serious injury were intracranial injury, fractures of facial bones, and vertebral injuries. The most common accident mechanisms were bicycling, horseback riding, and team ball sports, with bicycling causing most frequently serious injury. In conclusion, it is recommended using MDCT to rule out serious injury of the spine and pelvis in adult victims of high-energy accidents of all age groups and both genders, especially in regard to multilevel injuries and injuries of the cervical spine. Even in presumably minor trauma, a high level of suspicion is required, and MDCT should be employed if the clinical finding is uncertain. MDCT is fast, cost-effective, and demonstrates injuries of the spine and pelvis unambiguously, benefiting the trauma patient s outcome.Liikenneonnettomuuksista, putoamisesta tai muista vakavammista vammamekanismeista johtuvat traumat ovat yleisiä tapauksia tapahtuma-asemilla sekä kehittyneissä maissa että myös kehittyvässä maailmassa. Myös urheilu- ja vapaa-aikaonnettomuudet yleistyvät pysyvästi. Maailman terveysjärjestön (WHO) mukaan päivittäin noin 16.000 ihmistä kuolee trauman seurauksena, ja vielä useammat saavat pysyviä vammoja. Ensimmäisessä tunnissa tapahtuman jälkeen (ns. golden hour ) tehdyt hoitotoimenpiteet vaikuttavat eniten potilaan ennusteeseen, sekä tarkka että nopea diagnoosi on asianmukaisen hoidon edellytys. Perinteinen röntgentutkimus oli pitkään ainoa kuvantamismenetelmä kliinisen tutkimuksen rinnalla sisäisten vammojen arvioimiseksi tai poissulkemiseksi. Perinteisen röntgentutkimuksen heikkous on, että kuvien laatu ja tarkkuus voivat olla puutteellisia, erityisesti hätätapauksen yhteydessä. Myös kehon rakenteiden summaation vuoksi kuvat voivat olla epädiagnostiset, tai aiheuttaa, että vakavat vammat jäävät diagnosoimatta. Tämän vuoksi tietokonetomografia (computed tomography, CT) on yleistynyt viime vuosikymmenien aikana. CT on perinteistä röntgentutkimusta sekä tarkempi että herkempi. Erityisesti nykyaikainen monileiketietokonetomografia (multidetector computed tomography, MDCT) antaa erittäin korkeanlaatuisia kuvia lyhyessä tutkimusajassa, mikä mahdollistaa tarkan diagnoosin pään, selkärangan, lantion ja pehmytosien vammoista, josta monivammapotilas hyötyy. Haitat ovat tietokonetomografian suuri sädeannos ja mahdollinen allerginen reaktio traumatutkimusta varten välttämättömään varjoaineeseen. Primaaritutkimuksessa kiinnostaa ensisijaisesti, jos potilaalla on näkymättömiä verenvuotoja kallon, rintakehän tai vatsan sisällä. Toissijaisena huomio kiinnittyy hermoston vammoihin ja tukiluurangon stabiliteettiin. Kallo ja selkäranka sisältävät keskushermoston ja toimivat sen suojana. Stabilisoitumaton epästabiili murtuma näissä rakenteissa voi johtaa sekundaariseen hermoston tai luiden lähellä kulkevien verisuonten vammaan esimerkiksi siirtämisen yhteydessä, mikä voi johtaa pysyviin vammoihin tai jopa potilaan kuolemaan. Erityisesti lantion murtumiin liittyy korkea riski hallitsemattomasta vuodosta , ja etenkin epästabiilien murtumien yhteydessä vuoto saattaa olla kuolemaan johtava. Röntgenkuvausta käytetään usein vielä lantion tutkimiseen etenkin jos potilaan tila ei ole vakaa. Mikäli potilaan tila sallii kuvauksen ja lantio on esimerkiksi ulkoisesti stabiloitu, tietokonetomografia antaa selvästi tarkemman käsityksen anatomisesti monimutkaisen lantion vammoista ja pystyy usein osoittamaan vuotopaikankin siten, että suonensisäinen vuodon tukkiminen voidaan kohdentaa nopeasti oikean suonen alueelle. Tietokonetomografian yhteydessä tehdyt 3D reformaatit ovat lisäksi hyödyllisiä leikkauksen suunnittelemisprosessissa. Tämä tutkimus käsittelee tietokonetomografian tarkkuutta verrattuna perinteiseen röntgenkuvantamiseen selkärangan ja lantion alueella, ja antaa tietoa selkärankamurtumien demografisesta taustasta sekä tyypillisistä vammaprofiileista. Lisäksi tutkitaan vakavia vammoja urheilu- ja vapaa-aikaonnettomuuksien yhteydessä. Tutkimuksen lopputulos on, että korkeaenergia-trauman yhteydessä suositellaan tietokonetomografiaa ensisijaisena kuvantamismenetelmänä vakavien vammojen poissulkemiseksi, sekä selkärangan että lantion alueella. Vakavia vammoja näkyy usein monilla tasoilla, jonka vuoksi kuvantamisalueen tulee olla mahdollisemman laaja, ilman että potilaalle aiheutetaan turhaa säteilyrasitusta. Urheilu- ja vapaa-aikatapahtumien yhteydessä tavallisimmat vakavat vammat ovat pään sisäiset vammat, kasvojen luiden murtumat, ja selkärangan vammat. Tavallisimmat vammamekanismit ovat polkupyöräily, ratsastaminen, ja joukkuepallolajit. Eniten vakavia vammoja aiheuttaa polkupyöräily

SWAS observations of comet 9P/Tempel 1 and Deep Impact

On 4 July 2005 at 1:52 UT the Deep Impact mission successfully completed its goal to hit the nucleus of 9P/Tempel 1 with an impactor, forming a crater on the nucleus and ejecting material into the coma of the comet. The 370 kg impactor collided with the sunlit side of the nucleus with a relative velocity of 10.2 km/s. NASA's Submillimeter Wave Astronomy Satellite (SWAS) observed the 1(10)-1(01) ortho-water ground-state rotational transition in comet 9P/Tempel 1 before, during, and after the impact. No excess emission from the impact was detected by SWAS. However, the water production rate of the comet showed large natural variations of more than a factor of three during the weeks before the impact.Comment: to appear in the proceedings of the IAU Symposium No. 231: "Astrochemistry - Recent Successes and Current Callenges". Typo corrected in author affiliation lis

Ankylosis of the cervical spine increases the incidence of blunt cerebrovascular injury (BCVI) in CTA screening after blunt trauma

Purpose To examine the incidence, location, and grade of blunt cerebrovascular injury (BCVI), as well as associated strokes in patients with ankylosis of the cervical spine, imaged with CT angiography (CTA) after blunt trauma. The related etiologies of ankylosis had an additional focus. Materials and methods Altogether of 5867 CTAs of the craniocervical arteries imaged after blunt trauma between October 2011 and March 2020 were manually reviewed for a threshold value of ankylosis of at least three consecutive cervical vertebrae. BCVI was the primary outcome and associated stroke as the secondary outcome. Variables were craniofacial and cervical spine fractures, etiology and levels of ankylosis, traumatic brain injury, spinal hematoma, spinal cord injury, and spinal cord impingement, for which correlations with BCVI were examined. Results Of the 153 patients with ankylosis and blunt trauma of the cervical spine, 29 had a total of 36 BCVIs, of whom two had anterior and 4 posterior circulation strokes. Most of the BCVIs (n = 32) were in the vertebral arteries. Injuries were graded according to the Biffl scale: 17 grade II, 4 grade III, 14 grade IV, and 1 grade V. A ground-level fall was the most common trauma mechanism. Cervical spine fracture was the only statistically significant predictor for BCVI (OR 7.44). Degenerative spondylosis was the most prevalent etiology for ankylosis. Conclusion Ankylosis of the cervical spine increases the incidence of BCVI up to sevenfold compared to general blunt trauma populations, affecting especially the vertebral arteries.Peer reviewe

Remember the vessels! Craniofacial fracture predicts risk for blunt cerebrovascular injury

Purpose: The risk factors for blunt cerebrovascular injuries (BCVIs) are currently under intensive research, yet it is still controversial who should be screened. This study aimed to determine whether craniofacial fractures are associated with BCVI. Patients and Methods: This retrospective cohort study focused on patients with suspected polytrauma after whole-body computed tomographic angiography of the cervical arteries. Patients were reviewed for BCVI and craniofacial fractures. Exclusion criteria were hanging injury, gunshot injury or other penetrating injury to the neck, and a cervical fracture on any level. The outcome variable was BCVI, and the main predictor variable was a craniofacial fracture. A secondary predictor variable was a type of craniofacial fracture classified as a facial fracture, skull fracture, or a combination of facial and skull fracture. Other predictor variables were gender, age, and mechanism of injury In addition, specific craniofacial fractures were analyzed in more detail. The relevance of associations between BCVI and the predictors underwent chi(2) testing. Significance was set at .01. Results: Four hundred twenty-eight patients 13 to 90 years old during a 12-month period were included in the analysis. Craniofacial fractures occurred in 75 (17.5%). BCVI occurred significantly more frequently in those with than in those without a craniofacial fracture (18.6 vs 7.4%; P = .002). Patients with craniofacial fracture had a 4-fold increased risk for BCVI, whereas those 31 to 50 years old had 3.4-fold increased risk. Type of craniofacial fracture, gender, and mechanism of injury were not associated with BCVI. Conclusion: Craniofacial fractures are a serious risk factor for BCVI. This research suggests that in patients with any craniofacial fracture and suspected polytrauma, rigorous imaging of cervical arteries in search of BCVI is essential. (C) 2018 American Association of Oral and Maxillofacial SurgeonsPeer reviewe

Phosphorus donors in highly strained silicon

The hyperfine interaction of phosphorus donors in fully strained Si thin films grown on virtual Si$_{1-x}$Ge$_x$ substrates with $x\leq 0.3$ is determined via electrically detected magnetic resonance. For highly strained epilayers, hyperfine interactions as low as 0.8 mT are observed, significantly below the limit predicted by valley repopulation. Within a Green's function approach, density functional theory (DFT) shows that the additional reduction is caused by the volume increase of the unit cell and a local relaxation of the Si ligands of the P donor.Comment: 12 pages, 3 figure

Costal cartilage fractures in blunt polytrauma patients - a prospective clinical and radiological follow-up study

Purpose To assess the healing of costal cartilage fractures (CCFX) in patients with blunt polytrauma with follow-up imaging and clinical examination. Effect on physical performance and quality of life (QoL) was also evaluated. Methods The study group comprised twenty-one patients with diagnosed CCFX in trauma CT. All the patients underwent MRI, ultrasound, ultra-low-dose CT examinations, and clinical status control. The patients completed QoL questionnaires. Two radiologists evaluated the images regarding fracture union, dislocation, calcifications, and persistent edema at fracture site. An attending trauma surgeon clinically examined the patients, with emphasis on focal tenderness and ribcage mobility. Trauma registry data were accessed to evaluate injury severity and outcome. Results The patients were imaged at an average of 34.1 months (median 36, range 15.8-57.7) after the initial trauma. In 15 patients (71.4%), CCFX were considered stable on imaging. Cartilage calcifications were seen on healed fracture sites in all the patients. The fracture dislocation had increased in 5 patients (23.8%), and 1 patient (4.8%) showed signs of a non-stable union. Four patients (19.0%) reported persistent symptoms from CCFX. Conclusion Non-union in CCFX is uncommon but may lead to decreased stability and discomfort. Both clinical and radiological examinations play an important part in the post-traumatic evaluation of CCFX. CT and MRI visualize the healing process, while dynamic ultrasound may reveal instability. No significant difference in QoL was detected between patients with radiologically healed and non-healed CCFX. Post-traumatic disability was mostly due to other non-thoracic injuries.Peer reviewe

Saturn in hot water: viscous evolution of the Enceladus torus

The detection of outgassing water vapor from Enceladus is one of the great breakthroughs of the Cassini mission. The fate of this water once ionized has been widely studied; here we investigate the effects of purely neutral-neutral interactions within the Enceladus torus. We find that, thanks in part to the polar nature of the water molecule, a cold (~180 K) neutral torus would undergo rapid viscous heating and spread to the extent of the observed hydroxyl cloud, before plasma effects become important. We investigate the physics behind the spreading of the torus, paying particular attention to the competition between heating and rotational line cooling. A steady-state torus model is constructed, and it is demonstrated that the torus will be observable in the millimeter band with the upcoming Herschel satellite. The relative strength of rotational lines could be used to distinguish between physical models for the neutral cloud.Comment: submitted to Icarus updated: references fixe

Augmenting Denver criteria yields increased BCVI detection, with screening showing markedly increased risk for subsequent ischemic stroke

Purpose BCVI may lead to ischemic stroke, disability, and death, while being often initially clinically silent. Screening criteria for BCVI based on clinical findings and trauma mechanism have improved detection, with Denver criteria being most common. Up to 30% of patients do not meet BCVI screening criteria. The aim of this study was to analyze the effect of augmented Denver criteria on detection, and to determine the relative risk for ischemic stroke. Methods Denver screening criteria were augmented by any high-energy trauma of the cervical spine, thorax, abdomen, or pelvis. All acute blunt trauma WBCT including CT angiography (CTA) over a period of 38 months were reviewed retrospectively by two Fellowship-trained radiologists, as well as any cerebral imaging after the initial trauma. Results 1544 WBCT studies included 374 CTA (m/f = 271/103; mean age 41.5 years). Most common mechanisms of injury were MVA (51.5%) and fall from a height (22.3%). We found 72 BCVI in 56 patients (15.0%), with 13 (23.2%) multiple lesions. The ICA was affected in 49 (68.1%) and the vertebral artery in 23 (31.9%) of cases. The most common injury level was C2, with Biffl grades I and II most common in ICA, and II and IV in VA. Interobserver agreement was substantial (Kappa = 0.674). Of 215 patients imaged, 16.1% with BCVI and 1.9% of the remaining cases had cerebral ischemic stroke (p <.0001; OR = 9.77; 95% CI 3.3-28.7). Eleven percent of patients with BCVI would not have met standard screening criteria. Conclusions The increase in detection rate for BCVI justifies more liberal screening protocols.Peer reviewe

A map of OMC-1 in CO 9-8

The distribution of 12C16O J=9-8 (1.037 THz) emission has been mapped in OMC-1 at 35 points with 84" resolution. This is the first map of this source in this transition and only the second velocity-resolved ground-based observation of a line in the terahertz frequency band. There is emission present at all points in the map, a region roughly 4' by 6' in size, with peak antenna temperature dropping only near the edges. Away from the Orion KL outflow, the velocity structure suggests that most of the emission comes from the OMC-1 photon-dominated region, with a typical linewidthof 3-6 km/s. Large velocity gradient modeling of the emission in J=9-8 and six lower transitions suggests that the lines originate in regions with temperatures around 120 K and densities of at least 10^(3.5) cm^(-3) near theta^(1) C Ori and at the Orion Bar, and from 70 K gas at around 10^(4) cm^(-3) southeast and west of the bar. These observations are among the first made with the 0.8 m Smithsonian Astrophysical Observatory Receiver Lab Telescope, a new instrument designed to observe at frequencies above 1 THz from an extremely high and dry site in northern Chile.Comment: Minor changes to references, text to match ApJ versio