Reviews of Current Literature Stuart E. Mirvis, M.D., and Kathirkamaganathan Shanmuganathan, M.D. Department of Radiology, University of Maryland Medical System, Baltimore, Maryland

Ducic Y, Hebert PC, MacLachlan L, Neufeld K, Lamothe A. Description and evaluation of the vallecula sign: a new radiologic sign in the diagnosis of adult epiglottitis. Ann Emerg Med 1997;30:1-6.

The authors reviewed lateral soft tissue cervical radiographs from 26 adult patients with a diagnosis of epiglottitis estab- lished by direct visualization. Another 26 lateral cervical con- trol radiographs from patients being evaluated for the presence of foreign bodies or cervical trauma were also reviewed. The 56 "mixed" lateral cervical soft tissue studies were assessed for the presence or absence of a deep, well-defined vallecula that approached the level of the hyoid bone. Readers, including radiologists, emergency physicians, medical students, and oto- laryngology residents, reviewed the radiographs both be- fore and after attending a tutorial during which this sign was described.

Before and after the tutorial, the absence of a normal val- lecula was 78.5% and 98.2% sensitive, respectively, for the de- tection of adult epiglottitis (P < 0.0001), and specificity increased fi'om 78.5% to 99.5% (P < 0.0001) after the tuto- rial. Overall accuracy for the radiographic diagnosis of adult epiglottitis improved from 80.5% to 98.8% with application of this radiologic sign. All groups of reviewers showed simi- lar improved diagnostic accuracy. The authors caution that the vallecula sign was o~zly valid when the patient's bite was fully occluded, since opening the mouth allows posterior move- ment of the epiglottis, potentially obliterating the vallecula. The conclusion indicates that the use of the vallecula sign im- proves the diagnostic accuracy of the lateral soft tissue radi- ograph for the diagnosis of acute epiglottitis in the adult.

Branney SW, Moore EE, Cantrill SV, Burch JM, Terry SI. Ultrasound based key clinical pathway reduces the use of hospital resources for the evaluation of blunt abdominal trauma. J Trauma 1997;42:1086-90.

This study evaluates the use of emergency abdominal sonog- raphy in the setting of blunt trauma. A clinical pathway was

1 0 7 0 - 3 0 0 4 / 9 7 / 4 1 9 - 4 2 0 / $ 3 . 0 0 American Society of Emergency Radiology

Volume 4, Number 6 �9 1997

developed using sonography of the abdomen as the initial screening study for patients with blunt abdominal trauma who did not require emergent laparotomy. During a 3-month pe- riod, 486 patients entered the sonography protocol. The num- ber of computed tomographic (CT) scans, laparotomies, and diagnostic peritoneal lavage (DPL) procedures performed among this group and the types of injuries were compared to those in a historical cohort of 516 patients.

Between the two groups, no differences were found re- garding patient demographics, types of injuries, or number of laparotomies performed. The DPL rate was reduced from 17% to 4% and the CT rate from 56% to 26% by using the screen- ing abdominal sonogram protocol. Injury severity scores in- creased from 11.6 to 21.5 in patients undergoing DPL, and from 4.6 to 8.3 in patients having a CT scan. In 65% of all cases in the protocol group, only sonography was used ex- clusively for diagnosis. A potential reduction in total charges for CT and DPL was $110,000 over 3 months, partially off- set by potential charges of $38,700 for bedside sonography at $75 per study. The protocol resulted in a 38% reduction in patient hospitalizations for over 24 hours.

There was no comment in the article relating to falsely pos- itive or negative sonography examinations and their effect on patient management and total charges incurred among the protocol study group.

Gruenberg MF, Rechtine GR, Chrin AM, Sola CA, Ortolan EG. Overdistraction of cervical spine injuries with the use of skull traction: a report of two cases. J Trauma 1997;42:1152-6.

Two patients who sustained cervical spine overdistraction from skeletal traction are reviewed. One patient sustained a type 1 hangman's fracture and a C2/C3 distraction injury after ejection from a motor vehicle during a collision. The injury was noted on the admission lateral cervical radiograph, and displacement (distraction) increased after application of 10 pounds of in-line traction at the time of abdominal exploration. Fortunately, the patient remained asympto- matic neurologically and had an uneventful recovery after anterior fusion. The second patient sustained a unilateral facet dislocation. A magnetic resonance imaging (MR.I) study showed C5/C6 disc disruption, but no increase in disc height. The patient was given 11 pounds of in-line traction and was noted to have a C5/C6 overdistraction on subsequent lateral

E m e r g e n c y R a d i o l o g y �9 N o v e m b e r / D e c e m b e r 1997 R e v i e w s o f Current Literature ~ 419

cervical radiography. The overdistraction was reduced with a decrease in applied traction, and no neurologic deteriora- tion occurred.

The article highlights awareness of the potential for some cervical spine injuries to be very unstable, permitting overdis- traction with minimal applied traction. Often, the unstable injuries can be masked or inapparent or are assumed not to be mechanically unstable, as with the unilateral facet disloca- tion. The authors point out that cervical overdistraction in- juries are most common at the atlanto-occipital and atlantoaxial level. The authors recommend starting traction at no greater than 5 pounds regardless of the level of injury, with small in- cremental traction weight increases assessed by clinical and ra- diologic follow-up. The radiologist can be of help in emphasizing the potential instability of some cervical spine injuries, particularly when disruption of key stabilizing liga- ment(s) is documented on MRI.

Denton JR, Moore EE, Coldwell DM. Multimodality treatment for grade V hepatic injuries: perihepatic packing, arterial embolization, and venous stenting. J Trauma 1997;42:964-8.

This interesting case report proposes a new multidiscipli- nary approach that involves the trauma surgeon and inter- ventional radiologist in managing patients with a gradeV hepatic injury involving the retrohepatic vena cava. The au- thors used perihepatic packing for immediate definitive con- trol of hemorrhage, angiographic embolization of the hepatic artery for significant recurrent hepatic parenchymal hemor- rhage, and hepatic venous stent to treat bleeding from the he- patic veins. This multidisciplinary approach may help in the future to reduce the significantly high mortality rates (50-80%) for penetrating trauma and 90-100% for blunt trauma asso- ciated with high-grade liver injuries with retrohepatic vena cava involvement.

Cook PA, Yu JS, Wiand W, Cook AJ II, Coleman CR, Cook AJ. Suspected scaphoid fractures in skeletally immature patients: application of MRI. J Comput Assist Tomogr 1997;21:511-5.

This prospective study attempts to determine the role of MILl in evaluating pediatric patients with suspected scaphoid fractures. The small study group consisted of 18 patients with suspected scaphoid fractures. Four of the six scaphoid frac- tures diagnosed by MRI were initially occult on radiographs. On follow-up, all six scaphoid fractures became apparent on radiographs between 22 and 35 days after injury. Four patients with marrow edema alone and six patients without any MILl changes did not progress to scaphoid fractures. Since the clin- ical and radiographic signs helpful in diagnosing scaphoid frac- tures in adults are unreliable in this age group, the authors propose that the high negative predictive value of MRI (100%) would help to save time in treating these patients. A larger study is needed to validate these results.

Fielding JR, Fox LA, Heller H, Seltzer SE, Tempany CM, Silverman SG, Steele G. Spiral CT in the evaluation of flank pain: overall accuracy and feature analysis. J Comput Assist Tomogr 1997;21:635-8.

This retrospective study evaluates the CT features that have a strong positive and negative predictive value in diagnosing renal colic on unenhanced spiral CT. Each case was evaluated for CT findings including hydronephrosis, perinephric strand- ing or fluid, nephrocalcinosis, nephrolithiasis, hydroureter, ureteral stone, periureteral stranding, and ureterovesical junc- tion edema. Findings with a high (>90%) predictive value were ureteral stone, hydronephrosis, hydroureter, periureteral stranding, and ureterovesicaljunction edema. Findings with a high negative predictive value (>89%) were absence of hy- dronephrosis and hydroureter. The authors conclude that care- ful feature analysis should permit accurate diagnosis ofureteral obstruction by unenhanced thin-section spiral CT.

420 �9 R e v i e w s o f C u r r e n t Literature E m e r g e n c y R a d i o l o g y ~ N o v e m b e r / D e c e m b e r 1997