Malignant Transformation of an Aneurysmal Bone Cyst to Fibroblastic Osteosarcoma.

Aneurysmal bone cysts are uncommon primary bone tumors typically regarded as histologically and clinically benign. Malignant transformation of these lesions occurs almost exclusively in the context of prior radiation exposure. However, 4 cases of an osteosarcoma developing without prior radiation exposure have been reported. In this article, we report a fifth case of degeneration of an aneurysmal bone cyst to a fibroblastic osteosarcoma. In addition to reviewing the earlier cases, we describe the radiologic, pathologic, and immunohistochemical basis of this diagnosis.

Anal sphincter complex muscles defects and dysfunction in asymptomatic parous women.

INTRODUCTION AND HYPOTHESIS: We aimed to determine anatomy and function of anal sphincter complex using three-dimensional ultrasound (3D-US) and manometry in asymptomatic parous women. METHODS: 3D-US of puborectalis muscle (PRM), external (EAS), and internal anal sphincters (IAS) anatomy was performed in 45 women without pelvic floor dysfunction. To assess function, rest and squeeze vaginal and anal pressures were measured. Based on 3D-US, subjects were divided into injured and uninjured groups. RESULTS: Forty-four of 45 subjects had adequate PRM images. The injured PRM (N = 14) group had significantly lower vaginal pressures as compared with uninjured PRM group (N = 30; p = 0.001). Four of 45 subjects with IAS and EAS defects had lower resting and squeeze anal canal pressure. Muscle injury to IAS, EAS and PRM in the same individual was uncommon. CONCLUSIONS: In asymptomatic parous women, PRM defects were more common than the EAS/IAS defects but defects in more than one muscle were infrequent. Subjects with injured PRM had low vaginal pressure than the ones without.

Current practices in determining amnionicity and chorionicity in multiple gestations.

OBJECTIVE: To evaluate the accuracy of amnionicity and chorionicity (A/C) diagnosis of referral physicians and a tertiary care center as compared to histopathologic diagnosis. METHOD: A retrospective study of 289 multi-fetal gestations was performed comparing A/C diagnoses of referring physicians, a tertiary care center, and histopathology. RESULTS: Two hundred and eighty-nine multi-fetal pregnancies were referred for evaluation; only 43.6% (126/289) carried an accurate diagnosis of A/C before tertiary care center evaluation. The tertiary care center accurately identified A/C in 94.8% (274/289) overall and 100% in first trimester twins and triplets. Referrals with an unspecified A/C diagnosis included 46.1% (113/245) twins and 64.1% (25/39) triplets. CONCLUSION: Accurate diagnosis of A/C can be obtained by the early assessment of key sonographic findings. Referral providers are less accurate at determining A/C of multifetal gestation when compared to a tertiary center, suggesting that an emphasis should be placed on enhancing these diagnostic skills in the general community or encouraging referral when diagnosis is ambiguous.

Refining resuscitation strategies using tissue oxygen and perfusion monitoring in critical organ beds.

BACKGROUND: Muscle tissue oxygen monitoring (PmO2) holds promise as a continuous guide to resuscitation after hemorrhagic shock, but the relationship of muscle tissue oxygen to perfusion has not been described previously. On the other hand, brain tissue oxygen PbrO2 and perfusion as measured by cerebral blood flow (CBF) are already used clinically, especially as guides to vasopressor use in cerebral perfusion targeted therapy in patients with traumatic brain injury. This laboratory study was undertaken to describe the relative contributions of muscle perfusion and arterial oxygen tension (PaO2) to muscle tissue oxygen (PmO2) levels. Second, we wanted to compare the relationship between muscle oxygen and muscle blood flow (MBF) with simultaneously measured brain tissue oxygen and perfusion during the administration of a vasopressor and during experimental hemorrhagic shock. We hypothesized that muscle perfusion would be an important contributor to PmO2, thus underscoring the need for optimal fluid resuscitation after shock. We further hypothesized that PmO2 would decrease even as PbrO2 increased when vasopressor therapy was used. METHODS: Eight pigs were anesthetized, intubated, underwent splenectomies, and were instrumented to monitor PmO2, MBF, PbrO2, and CBF. Oxygen challenges were performed by increasing PaO2 from 100 to 500 mm Hg during three different experimental phases: baseline, vasopressor administration, and hemorrhage. Mean PmO2 and MBF were compared at the beginning and end of each experimental phase and correlations between PmO2, MBF, PbrO2, CBF, and traditional endpoints of resuscitation were investigated. RESULTS: During oxygen challenges in all phases, PmO2 increased (31.2 +/- 16.6 mm Hg to 56.6 +/- 34.1 mm Hg; p < 0.01), whereas MBF did not change significantly (16.4 +/- 11.3 mL/100 g/min to 15.4 +/- 11.9 mL/100 g/min). On administration of vasopressors, MBF decreased (18 +/- 8.8 mL/100 g/min to 5.3 +/- 3 mL/100 g/min; p = 0.03), but no change in PmO2 was detected. During hemorrhage, both PmO2 and MBF declined (PmO2: 40 +/- 8.8 mm Hg to 7.7 +/- 9.6 mm Hg; p = 0.002; MBF: 9.8 +/- 5.8 mL/100 g/min to 3.3 +/- 2.4 mL/100 g/min; p = 0.046). Both PmO2 and MBF showed strong relationships with measurements of resuscitation, base deficit (PmO2 and MBF: p < 0.01), and mean arterial pressure (PmO2: p < 0.01, MBF: p = 0.02). Like PmO2 and MBF, PbrO2 and CBF decreased uniformly during hemorrhage. However, on vasopressor administration, CBF and PbrO2 increased significantly, whereas MBF decreased. CONCLUSION: PmO2 and MBF can be monitored simultaneously and continuously and correlate well with measurements of resuscitation. PmO2 values reflect both local perfusion and arterial oxygen tension. The clinical application of PmO2 as a continuous endpoint of resuscitation and its relationship to muscle perfusion warrants further study in critically injured patients and these investigations may help to refine resuscitation strategies.

Mental illness as an independent risk factor for unintentional injury and injury recidivism.

BACKGROUND: Twelve percent of Americans are diagnosed and treated for mental illness annually. The relationship between mental illness and intentional injuries such as assault and suicide has previously been described. However, unintentional injury among mentally ill adults has not been characterized. The purpose of this study was to identify relationships between mental illness diagnosis and unintentional injury. We hypothesized that diagnosed mental illness is an independent risk factor for unintentional injury and it increases the risk of recidivism. METHODS: In this retrospective cohort study, trauma registry data, medical records, and outpatient mental health care data from the San Francisco Department of Public Health Billing Information System (BIS) were used to identify patients admitted with unintentional injury at a Level I urban trauma center in 2003 and 2004. Data collected included mechanism of injury, patient outcome and disposition, mental health diagnoses, substance abuse history, presence of homelessness, number of repeat injury events, and outpatient mental health treatment history. The incidence of unintentional injury requiring admission to a trauma center and the risk of intentional injury recidivism in subjects with a mental illness diagnosis were compared with those in subjects without a mental illness diagnosis. The risk of recidivism in those who had received publicly funded outpatient treatment before their injury was also evaluated. RESULTS: Of the 1,709 patients admitted for unintentional injury, 20% had a diagnosis of mental illness. Individuals with mental illness had twice the rate of unintentional injury requiring admission (2.2-2.4 people in 1,000 vs. 1.0-1.1 in 1,000) and 4.5 times the odds of injury recidivism (odds ratio [OR] = 4.5, 95% confidence interval [CI] 3.3-6.1) as those who did not have a mental illness diagnosis. Mental illness was a more robust predictor of injury recidivism than substance abuse (OR = 3.2, 95% CI 2.3-4.3) or homelessness (OR = 2.3, 95% CI 1.5-3.4). Compared with the nonmentally ill group, subjects with mental illness had a longer hospital stay and were less likely to be discharged home. Also, their injuries were more likely the result of falling or being hit by cars, and less likely the result of motor vehicle collisions than subjects without mental illness. CONCLUSIONS: Mental illness is an independent risk factor for unintentional injury and injury recidivism. Individuals with mental illness also have a different pattern of injury and hospitalization. They tended to suffer from different mechanisms of injury, stayed in the hospital longer, and were more likely to be discharged to a skilled nursing facility. Recognition of mental illness as a risk factor for injury may prompt re-examination of resource allocation for mental health and injury prevention and highlights the mentally ill as a prime target population for unintentional injury prevention efforts.

Continuous muscle tissue oxygenation in critically injured patients: a prospective observational study.

BACKGROUND: Despite normalization of vital signs, critically injured patients may remain in a state of occult underresuscitation that sets the stage for sepsis, organ failure, and death. A continuous, sensitive, and accurate measure of resuscitation after injury remains elusive. METHODS: In this pilot study, we evaluated the ability of two continuous measures of peripheral tissue oxygenation in their ability to detect hypoperfusion: the Licox polarographic tissue oxygen monitor (PmO2) and the InSpectra near-infrared spectrometer (StO2). We hypothesized that deltoid muscle tissue oxygenation measurements could detect patients in "occult shock" who are at increased risk for post-injury complications. The study was designed to (1) define values for PmO2 and StO2 in patients who by all standard measures appeared to be clinically resuscitated; (2) evaluate the relationship between PmO2, StO2 and other physiologic variables including mean arterial pressure (MAP), lactate and base deficit (BD); and (3) examine the relationship between early low tissue oxygen values and the subsequent development of infections and organ dysfunction. Licox probes were inserted into the deltoid muscle of critically injured patients after initial surgical and radiologic interventions, and transcutaneous StO2 monitors were applied over the same muscle bed. PmO2, StO2, and standard physiologic data were collected continuously using a multimodal bioinformatics system. RESULTS: Twenty-eight critically injured patients were enrolled in this study at admission to the intensive care unit (ICU). For patients who appeared to be well resuscitated (defined as MAP > or = 70 mm Hg, heart rate [HR] < or = 110 bpm, BD > or = -2, and partial pressure of arterial oxygen (PaO2) = 80 and 150 mm Hg), the mean PmO2 was 34 +/- 11 mm Hg and StO2 was 63 +/- 27%. There was a strong relationship between PmO2 and BD (p < 0.001) but no significant relationship between StO2 and BD. The relationship between PmO2 and StO2 was weak but statistically significant. Early low values of both PmO2 and StO2 identified patients at risk for infectious complications or multiple organ failure (MOF). In patients who were well resuscitated by standard continuous parameters (HR and MAP), low PmO2 during the first 24 hours after admission (PmO2 < or = 25 for at least 2 hours) was strongly associated with the development of infectious complications (Odds Ratio = 16.5, 95% CI 1.49 to 183, p = 0.02). CONCLUSIONS: PmO2 is a responsive, reliable and continuous monitor of changes in base deficit. Initial low values for either PmO2 or StO2 were associated with post-injury complications. PmO2 monitoring may be useful in identifying patients in the state of occult underresuscitation who remain at risk for developing infection and MOF.