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Biomedical subjects

F A Mann

Publications and source records attributed to F A Mann.

At least 37 records · Page 2Linked to original sources
PubMed2000

Helical CT in the primary trauma evaluation of the cervical spine: an evidence-based approach.

This review provides a summary of the cost-effectiveness, clinical utility, performance, and interpretation of screening helical cervical spine CT for trauma patients. Recent evidence supports the use of helical CT as a cost-effective method for screening the cervical spine in high-risk trauma patients. Screening cervical spine CT can be performed at the time of head CT to lower the cost of the evaluation, and when all short- and long-term costs are considered, CT may actually save money when compared with traditional radiographic screening. In addition to having higher sensitivity and specificity for cervical spine injury, CT screening also allows more rapid radiological clearance of the cervical spine than radiography. Patients who are involved in high-energy trauma, who sustain head injury, or who have neurological deficits are candidates for CT screening. Screening with CT may enhance detection of other potentially important injuries of the cervical region.

Cervical Vertebrae↗
PubMed2000

Communicating with the family: the risks of medical radiation to conceptuses in victims of major blunt-force torso trauma.

BACKGROUND: Trauma surgeons must balance the risk and benefits of diagnostic radiographic procedures on potentially pregnant patients and should know the range and likelihood of effects that radiation might have on pregnancy. METHODS: We present guidelines for assessing such radiation risks. Knowledge of a patient's pregnancy status and an estimate of radiation dose to the conceptus (low, < 10 mGy [milligray]; intermediate, 10-250 mGy; high, > 250 mGy) allow provisional assessment of radiation-induced risks. RESULTS: Dose estimates may be estimated at 2 mGy per exposure (radiographs), 5 mGy per slice (computed tomography), and 10 mGy per minute of fluoroscopy, when the conceptus is within the x-ray field. A formal radiation exposure assessment is appropriate when provisional estimates exceed 10 mGy. CONCLUSION: A simple qualitative dose assessment can inform clinical decisions and guide appropriate triage to more formal quantitative assessment.

Family↗
PubMed2000

Radiologic spectrum of craniocervical distraction injuries.

Injuries to the atlanto-occipital region, which range from complete atlanto-occipital or atlantoaxial dislocation to nondisplaced occipital condyle avulsion fractures, are usually of critical clinical importance. At initial cross-table lateral radiography, measurement of the basion-dens and basion-posterior axial line intervals and comparison with normal measurements may help detect injury. Computed tomography (CT) with sagittal and coronal reformatted images permits optimal detection and evaluation of fracture and luxation. CT findings that may suggest atlanto-occipital injury include joint incongruity, focal hematomas, vertebral artery injury, capsular swelling, and, rarely, fractures through cranial nerve canals. Magnetic resonance (MR) imaging of the cervical spine with fat-suppressed gradient-echo T2-weighted or short-inversion-time inversion recovery sequences can demonstrate increased signal intensity in the atlantoaxial and atlanto-occipital joints, craniocervical ligaments, prevertebral soft tissues, and spinal cord. Axial gradient-echo MR images may be particularly useful in assessing the integrity of the transverse atlantal ligament. All imaging studies should be conducted with special attention to bone integrity and the possibility of soft-tissue injury. Atlanto-occipital injuries are now recognized as potentially survivable, although commonly with substantial morbidity. Swift diagnosis by the trauma radiologist is crucial for ensuring prompt, effective treatment and preventing delayed neurologic deficits in patients who survive such injuries.

Atlanto-Axial Joint↗
PubMed2000

Determining risk of traumatic aortic injury: how to optimize imaging strategy.

OBJECTIVE: Our objective was to develop and validate a clinical prediction rule that determines patient probability of traumatic aortic injury to guide selection of optimal screening imaging strategy. MATERIALS AND METHODS: A 2-year, single-institution retrospective case-control study was conducted of 31 cases of traumatic aortic injury and 171 random major trauma control subjects. The presence of potential injury predictors was determined from chart review. Logistic regression was used to determine injury predictors, and clinically similar predictors were combined into composite predictors. The composite predictors were used to develop a seven-point injury index clinical prediction rule using multivariate logistic regression. Injury probabilities were determined through Bayes' theorem. Bootstrap validation was performed. RESULTS: Predictors of aortic injury included head injury (odds ratio, 18.3; 95% confidence interval [CI], 7.3-46), pelvic fracture (odds ratio, 27.3; 95% CI, 8.8-85), pneumothorax (odds ratio, 27.3; 95% CI, 8.8-85), and lack of seat belt use (odds ratio, 6.8; 95% CI, 2.6-17). The seven composite predictors of age, unrestrained vehicle occupant, hypotension, thoracic injury, abdominopelvic injury, extremity fracture, and head injury, were combined into the seven-point injury index. In the injury index, each composite predictor had an adjusted odds ratio of 7.1 (95% CI, 3.7-13.5), and the odds ratios were additive. The injury index prediction rule had an area under the receiver operating characteristic curve of 0.97. All injured patients had at least one composite predictor. CONCLUSION: The probability of traumatic aortic injury can be estimated from the injury index prediction rule. Because cost-effectiveness of various imaging strategies depends on probability of injury, the prediction rule can guide imaging selection.

Aorta↗
PubMed2000

Cervical spine injury: a clinical decision rule to identify high-risk patients for helical CT screening.

OBJECTIVE: We aimed to validate the routine use of a clinical decision rule to direct diagnostic imaging of adult blunt trauma patients at high risk for cervical spine injury. MATERIALS AND METHODS: We previously developed and have since routinely used a prediction rule based on six clinical parameters to identify patients at greater than 5% risk of cervical spine injury to undergo screening helical CT of the cervical spine. During a 6-month period, 4285 screening imaging studies of the cervical spine were performed in adult blunt trauma patients. Six hundred one patients (398 males, 203 females; age range, 16-100 years; median age, 38 years) underwent helical CT, and the remainder underwent 3684 conventional radiographic examinations. Clinical and report data were extracted from the radiology department database, medical records, and the hospital trauma registry. Abnormal findings were independently confirmed by additional imaging studies, autopsy results, or clinical outcome. RESULTS: The true-positive cervical spine injury rates in helical CT- and conventional radiography-screened patients who presented directly to our trauma center were 40 (8.7%) of 462 and seven (0.2%) of 3684, respectively. The cervical spine injury rate in patients who were transferred from outside institutions to our trauma center and who underwent helical CT was 37 (26.6%) of 139. This figure included 20 patients already known to have cervical spine fracture. CONCLUSION: The clinical decision rule can distinguish patients at high and low risk of cervical spine injury, thus supporting its validity.

Adolescent↗
PubMed2000

Use of structural allografts in spinal osteomyelitis: a review of 47 cases.

OBJECT: The use of structural allografts in spinal osteomyelitis remains controversial because of the perceived risk of persistent infection related to a devitalized graft and spinal hardware. The authors have identified 47 patients over the last 3.5 years who underwent a surgical decompression and stabilization procedure in which fresh-frozen allografts were used after aggressive removal of infected and devitalized tissue. The patients subsequently underwent 6 weeks of postoperative antibiotic therapy (12 months for those with tuberculosis [TB]). METHODS: Follow-up data included results of serial clinical examinations, radiography, laboratory analysis (erythrocyte sedimentation rate and white blood cell count), and clinical outcome questionnaires. Of the original 47 patients (14 women and 33 men, aged 14-83 years), 39 were available for follow up. The average follow-up period at the time this article was submitted was 17 +/- 9 months (median 14 months, range 6-45 months). In the majority of cases (57%), a Staphylococcus species was the infectious organism. Predisposing risk factors included intravenous drug abuse (IVDA), previous surgery, diabetes, TB, and concurrent infections. During the follow-up period only two patients suffered recurrent infection at a contiguous level; both had a history of IVDA and one also had a chronic excoriating skin condition. No other recurrent infections have been identified, and no patient has required reoperation for persistent infection or allograft/hardware failure. CONCLUSIONS: It is the authors' opinion that the use of structural allografts in combination with aggressive tissue debridement and adjuvant antibiotic therapy provide a safe and effective therapy in cases of spinal osteomyelitis requiring surgery.

Adolescent↗
PubMed1999

Centrifugal pumps: description of devices and surgical techniques.

BACKGROUND: Because of simplicity of application, universal access, and low cost, centrifugal pumps are commonly used for short-term mechanical cardiac assist. Indications and techniques for application of this technology continue to evolve. METHODS: The clinical experience with 151 patients undergoing centrifugal mechanical cardiac assist at the University of Missouri-Columbia has been reviewed. We have compared commonly available centrifugal pumping systems in vitro and in vivo for characteristics that might distinguish them. RESULTS: Centrifugal pumps have been found to be well suited for use in surgery on the thoracic aorta, for extracorporeal membrane oxygenation and for postcardiotomy cardiac mechanical assist. Complications associated with centrifugal mechanical assist are predictable and common but potentially can be reduced by improved surgical techniques and anticoagulation strategies. In vitro and in vivo experimentation with available centrifugal pumps reveals nuances characteristic of each of the devices. CONCLUSIONS: All centrifugal pumps presently available are less destructive to blood cellular elements compared with roller pumps. With familiarity, all can function satisfactorily for short-term mechanical assist with no compelling evidence that favors any particular centrifugal pump system clinically available. Centrifugal pumps are ideally suited for left heart bypass during surgery on a thoracic aorta and for short-term application as may be required for postcardiotomy mechanical assist. Centrifugal pump technology should be part of the armamentarium of all cardiothoracic surgeons.

Animals↗
PubMed1999

Radiologic measurement of the scapholunate joint: implications of biologic variation in scapholunate joint morphology.

To determine the optimal location for measurement of the scapholunate (SL) joint intercortical width, normal biologic variation in SL joint morphology was evaluated in 40 normal, skeletally mature wrists (16 volunteers, 24 cadavers) using thin-section 1.5T magnetic resonance imaging performed in the axial and coronal planes. The integrity of the SL ligaments was confirmed by magnetic resonance imaging and verified with anatomic dissection of the cadaver wrists. Patterns of SL articular morphology were qualitatively determined using similarity grouping. Scapholunate interval measurements were made at 3 locations each on the mid-SL joint image from both the axial and coronal planes: the articular margins (dorsal-palmar and proximal-distal) and midjoint. Three patterns of midjoint space cortical conformation were observed: parallel congruent (78%), inverted Y (15%), and point-like (8%). The most consistent and narrowest distance between the scaphoid and lunate was found at midjoint: coronal 1.45 mm (44% coefficient of variation) and axial 1.00 mm (22% coefficient of variation). This study demonstrated that measurement of the apparent SL joint interval in an inappropriate site, as with extended or flexed clenched fist views, may provide inaccurate SL joint interval distance assessments. Regardless of SL joint configuration, the midportion of the SL joint shows only moderate biologic variation and the least absolute measurement variance in width and should be the most precise part of the joint to measure. On magnetic resonance imaging, the normal SL joint interval measures less than 2 mm.

Adolescent↗
PubMed1999

Cervical spine tomography with an angiographic C-arm.

Phantom studies were performed to develop a technique for linear tomography of the craniocervical junction with a digital fluoroscopic angiographic C-arm unit. Section thicknesses were similar to those used at conventional tomography, and the radiation dose was lower. C-arm tomography was possible with a 6-second exposure and a 40 degrees arc. C-arm tomography is a practical method for decreasing patient turnaround time.

Angiography, Digital Subtraction↗
PubMed1999

Cervical spine imaging in patients with trauma: determination of fracture risk to optimize use.

PURPOSE: To develop a method to use clinically apparent factors to determine cervical spine fracture risk to guide selection of optimal imaging strategies. MATERIALS AND METHODS: Records from 472 patients with trauma (168 with fractures, 304 control patients) who visited the emergency department in 1994 and 1995 were reviewed for 20 potential predictors of cervical spine fracture in this retrospective case-control study. Simple logistic regression was used to determine predictors of cervical spine fracture. Prediction rules were formulated by using multiple logistic regression and recursive partitioning with bootstrap validation. Posttest fracture probabilities were calculated from base prevalence and likelihood ratios derived for predictors by using Bayes theorem. RESULTS: Predictors of cervical spine fracture included severe head injury (adjusted odds ratio [OR] = 8.5, 95% CI: 4.0, 17.0), high-energy cause (OR = 11.6, 95% CI: 5.4, 25.0), and focal neurologic deficit (OR = 58, 95% CI: 12, 283). The prediction rule was used to stratify patients into groups with fracture probabilities of 0.04%-19.70%. After adjusting for overfitting, the area under the receiver operating characteristic curve was 0.87. CONCLUSION: Clinically apparent factors, including cause of injury, associated injuries, and age, can be used to determine the probability of cervical spine fracture. Development of evidence-based imaging guidelines should incorporate knowledge of fracture probability.

Adult↗
PubMed1999

Cervical spine screening with CT in trauma patients: a cost-effectiveness analysis.

PURPOSE: To investigate the cost-effectiveness of computed tomography (CT) relative to radiography for cervical spine screening in trauma patients. MATERIALS AND METHODS: A decision analysis model was constructed to compare the incremental cost-effectiveness of radiography and CT as primary cervical spine screening modalities in trauma patients. Analyses were performed from a societal perspective, and probability and cost estimates from the literature and institutional experience were used. In separate cost-effectiveness analyses, hypothetical cohorts of trauma patients from three defined clinical scenarios were considered: high, moderate, and low risk for cervical spine fracture. Outcome measures included cases of paralysis prevented, total cost of screening strategies, and incremental cost-effectiveness ratios. RESULTS: In high-risk patients, screening with CT is a dominant strategy that prevents cases of paralysis and saves money for society. In moderate-risk patients, screening with CT is cost-effective with reference-case assumptions and within the range of most sensitivity analyses. In the low-risk group, CT screening helps prevent cases of paralysis, but the incremental cost-effectiveness ratio is high (> $80,000 per quality-adjusted life year). CONCLUSION: CT is the preferred cervical spine screening modality in trauma patients at high and moderate risk for cervical spine fracture.

Adult↗
PubMed1998

Ionized and total magnesium concentrations in blood from dogs with naturally acquired parvoviral enteritis.

OBJECTIVE: To determine whether pretreatment total and ionized blood magnesium concentrations were associated with outcome for dogs with parvoviral enteritis and whether ionized magnesium concentration was related to total magnesium concentration or other laboratory values. DESIGN: Prospective cohort study. ANIMALS: 61 healthy dogs and 72 dogs with parvoviral enteritis. PROCEDURE: Total, ionized, and pH-normalized ionized magnesium concentrations, ionized and pH-normalized ionized calcium concentrations, pH, sodium and potassium concentrations, and Hct were measured prior to treatment. chi 2 Analyses were used to test for associations between outcome and age and between outcome and treatment with antiendotoxin antibody. Pearson's correlation coefficients were calculated to determine whether ionized magnesium concentration was linearly associated with other laboratory values. RESULTS: Total and ionized magnesium concentrations were not significantly different between healthy dogs and dogs with parvoviral enteritis or between dogs surviving and those not surviving parvoviral enteritis. The only laboratory value strongly correlated with ionized magnesium concentration was pH-normalized ionized magnesium concentration. Of the factors tested, none were significantly associated with outcome, except that dogs 16 weeks old or less treated with antiendotoxin antibody were significantly more likely to die than were dogs 16 weeks old or less that were not treated with antiendotoxin antibody. CLINICAL IMPLICATIONS: Total and ionized blood magnesium concentrations cannot be used to consistently predict outcome for dogs with parvoviral enteritis. Antiendotoxin antibody should be used with caution in dogs 16 weeks old or less.

Age Factors↗
PubMed1998

Triple-injection wrist arthrography: unidirectional communications are due to technical factors.

One justification for triple-injection wrist arthrography is detection of unidirectional interjoint communication that might escape notice if only a single joint were injected. To determine whether the direction of 1-way communications is related to the choice of the first joint injected, the authors prospectively randomized 100 wrists undergoing consecutive single-contrast, fluoroscopically controlled arthrograms into 2 well-matched groups. One group received the initial injections into the midcarpal and distal radioulnar joints and the other group received the initial injection into the radiocarpal joint. Two unidirectional radial capsular communications with the radiocarpal joint were detected on delayed midcarpal joint injection. No other unidirectional communications were found. No statistically significant difference was found between the midcarpal and radiocarpal study groups. Thus, the first joint injected appears to be a major determinant in demonstrating unidirectional communications between wrist compartments.

Adult↗
PubMed1998

Sciatic perineal hernia in two dogs.

A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia.

Animals↗