X-ray Imaging Versus Anatomical Dissection for Identification of the Fabella.

INTRODUCTION: Reported prevalence rates of the fabella sesamoid bone vary widely, particularly between studies based on either X-ray imaging or anatomical dissection approaches. The purpose of this study was to directly compare these two methodologies in their detection of fabellae and investigate whether variability in the density of fabellae could explain any discrepancies. METHODS: Fifty cadaveric knee segments were examined for the presence of a fabella by both X-ray imaging and anatomical dissection. The relative density of each excised fabella specimen was then quantified using a separate set of radiographs.  Results: Fabellae were detected in 40% of the sample knees via a manual dissection approach but in just 12% of those same specimens using X-ray imaging. Relative density measurements confirmed that fabellae identifiable only via dissection were significantly less dense than fabellae visible in whole knee radiographs but denser than the surrounding tissue. CONCLUSION: Radiology cannot reliably detect cartilaginous or incompletely ossified fabellae, which were found in 28% of the study population. Clinicians should consider the potential occurrence of a fabella when diagnosing posterolateral knee pain, even if it may not be visible via X-ray.

Rules to limp by: joint compensation conserves limb function after peripheral nerve injury.

Locomotion persists across all manner of internal and external perturbations. The objective of this study was to identify locomotor compensation strategies in rodent models of peripheral nerve injury. We found that hip-to-toe limb length and limb angle was preferentially preserved over individual joint angles after permanent denervation of rat ankle extensor muscles. These findings promote further enquiry into the significance of limb-level function for neuromechanical control of legged locomotion.

A Unique Variation of Quadratus Plantae in Relation to the Tendons of the Midfoot.

A novel combination of variations involving the quadratus plantae muscle (QP) and its relationship to the flexor hallucis longus (FHL) tendon was observed unilaterally in the right foot of an 88-year-old female cadaver during routine dissection. The medial head of QP was observed inserting onto the tendon of FHL rather than the tendon of flexor digitorum longus (FDL), while also contributing to an anomalous tendinous slip to the second digit in conjunction with the tendon of FHL. The tendon of FHL also gave off a slip to the third digit. Both tendinous slips attached distally to the digital tendons of FDL. Lastly, the lateral head of QP inserted onto the tendinous slip from FHL to the third digit. Ninety-five additional feet were assessed for these variations, but none were observed. This combination of variations expands upon the proposed actions of QP in the literature. Furthermore, connections between the tendons of the midfoot are of clinical significance for harvesting tendon grafts.

Correlation between respiratory syncytial virus (RSV) test data and hospitalization of children for RSV lower respiratory tract illness in Florida.

BACKGROUND: Florida experiences year-round outbreaks of respiratory syncytial virus (RSV), but it is unknown if there is a correlation between RSV virology data and disease-related hospitalizations. We analyzed RSV surveillance and hospitalization data for the state of Florida to determine if there is an association between seasonal virology data and the incidence of International Classification of Diseases, 9th revision, clinical modification (ICD-9-CM) coded hospitalizations for RSV lower respiratory tract illness. METHODS: We conducted a retrospective analysis for each of 5 regions of Florida for 4 years (2001-2004) of monthly RSV surveillance data presented on the Florida Department of Health website and hospitalization data provided by the Agency for Health Care Administration. RSV was considered present when > or =10% of laboratory tests were positive in a given month and the duration of seasons was determined by the number of consecutive months threshold values were exceeded. Hospitalizations in children 24 months of age and younger were defined as RSV related if any of the following RSV-specific ICD-9-CM codes appeared on the discharge summary: 079.6 RSV; 466.11 acute bronchiolitis caused by RSV; and 480.1 pneumonia caused by RSV. RESULTS: RSV circulated year-round statewide and seasons ranged from 7-8 months in the southwest, northwest, and north regions of Florida to 11-12 months in the central and southeast regions, respectively. More than 23,000 children younger than 24 months of age were hospitalized throughout the state for an RSV-related illness during the 4-year period, with almost 20,000 (86%) of the admissions in infants less than 12 months of age. There were 23 hospitalizations yearly per 1000 births and more than 90% of discharges occurred during the defined RSV seasons. CONCLUSIONS: To our knowledge, this is the first study to demonstrate a positive correlation between RSV test data and hospitalizations both statewide and for individual regions within Florida. It would be prudent for clinicians to obtain results of local RSV virology data to guide decisions on timing of prophylaxis to prevent RSV hospitalizations.

X-ray kinematics analysis of vaginal scent marking in female Syrian hamsters (Mesocricetus auratus).

Vaginal marking is a stereotyped scent marking behavior in female Syrian hamsters used to attract male hamsters for mating. Although the modulation of vaginal marking by hormones and odors is well understood, the motor control of this proceptive reproductive behavior remains unknown. Therefore, we used X-ray videography to visualize individual bone movements during vaginal marking. Kinematic analyses revealed several consistent motor patterns of vaginal marking. Despite exhibiting a diversity of trial-to-trial non-marking behaviors (e.g. locomotor stepping), we found that lowering and raising the pelvis consistently corresponded with coordinated flexion and extension cycles of the hip, knee, and tail, suggesting that these movements are fundamental to vaginal marking behavior. Surprisingly, we observed only small changes in the angles of the pelvic and sacral regions, suggesting previous reports of pelvic rotation during vaginal marking may need to be reconsidered. From these kinematic data, we inferred that vaginal marking is primarily due to the actions of hip and knee extensor muscles of the trailing leg working against gravity to support the weight of the animal as it controls the descent of the pelvis to the ground. The cutaneous trunci muscle likely mediates the characteristic flexion of the tail. Interestingly, this tail movement occurred on the same time scale as the joint kinematics suggesting possible synergistic recruitment of these muscle groups. These data therefore provide new targets for future studies examining the peripheral control of female reproductive behaviors.

High-speed X-ray video demonstrates significant skin movement errors with standard optical kinematics during rat locomotion.

The sophistication of current rodent injury and disease models outpaces that of the most commonly used behavioral assays. The first objective of this study was to measure rat locomotion using high-speed X-ray video to establish an accurate baseline for rat hindlimb kinematics. The second objective was to quantify the kinematics errors due to skin movement artefacts by simultaneously recording and comparing hindlimb kinematics derived from skin markers and from direct visualization of skeletal landmarks. Joint angle calculations from skin-derived kinematics yielded errors as high as 39 degrees in the knee and 31 degrees in the hip around paw contact with respect to the X-ray data. Triangulation of knee position from the ankle and hip skin markers provided closer, albeit still inaccurate, approximations of bone-derived, X-ray kinematics. We found that soft tissue movement errors are the result of multiple factors, the most impressive of which is overall limb posture. Treadmill speed had surprisingly little effect on kinematics errors. These findings illustrate the significance and context of skin movement error in rodent kinematics.

Fatality rates in published reports of RSV hospitalizations among high-risk and otherwise healthy children.

OBJECTIVE: To review the fatalities among children hospitalized with respiratory syncytial virus (RSV) infection, and identify factors leading to a fatal outcome. RESEARCH DESIGN AND METHODS: Review of literature identified from a structured search of PubMed (1966-2009) using the following Medical Subject Headings: respiratory syncytial virus infection; hospitalized; infants; and risk factors. Publications were restricted to: English language; full papers; inclusion of > or =10 subjects; children aged < or =18 years, hospitalization for RSV infection; and deaths reported. Case fatality rates were defined as number of deaths divided by number of children hospitalized for RSV and were calculated for each study. RESULTS: Thirty-six studies met the inclusion and exclusion criteria. Case fatality rates among children hospitalized for RSV ranged from 0 to 33%. In general, studies showed that subgroups of high-risk children (chronic lung disease [CLD] 3.5-23%, congenital heart disease [CHD] 2-37%, and prematurity 0-6.1%) had higher fatality rates than older or otherwise healthy children (consistently <1%). Presence of severe underlying comorbidities such as neuromuscular disease, immunosuppression, and malignancies was associated with death among term and/or older (>1 year) children. Higher fatality rates were reported for infants receiving intensive unit care (1.1-8.6%), extracorporeal life support (33%) or for those who acquired nosocomial RSV infection (0-12.2%). The majority of studies did not report cause of death and clinical details of the fatal cases were often not provided. Other limitations of this review include our search limits, the possibility of inherent bias in our methodology that could result in an under or over estimation of case-fatality rates, and potential publication bias. CONCLUSIONS: Children at high risk for RSV (CLD, CHD and prematurity), those with severe underlying comorbidities, or those with nosocomial RSV appear to be at increased risk for death after RSV hospitalization. More data are needed on cause of death and how much is directly attributable to RSV.

Influenza vaccination with a live attenuated vaccine.

Influenza is a highly contagious, acute respiratory illness with a long history of outbreaks dating back several centuries. Although immunization is an effective means of protection against influenza, vaccination rates have been suboptimal, especially among certain high-risk groups, including children and health care personnel. This article reviews basic information about influenza and immunization, discusses the relevance of children as vectors of disease, and highlights current information on FluMist, an intranasally administered, live attenuated influenza vaccine, including studies of its use compared with trivalent inactivated vaccine and in children.

Respiratory syncytial virus: seasonal data for regions of Florida and implications for palivizumab.

BACKGROUND: The aims of this study are to define the length of the respiratory syncytial virus (RSV) season throughout Florida and evaluate the American Academy of Pediatrics (AAP) guidelines on the administration of palivizumab in light of the Florida data. METHODS: We retrospectively analyzed four seasons of monthly RSV surveillance data housed on the Florida Department of Health website for regional trends in RSV outbreaks. RESULTS: RSV circulated year round in Florida, with December being the peak month for RSV activity statewide. Regional virology data showed consistent patterns throughout the observation period, and all regions experienced widespread RSV activity for at least seven months of the year. The southeast region experienced the longest RSV seasons (10-12 mo), with year round outbreaks observed during 2000 to 2001 and 2001 to 2002. CONCLUSIONS: Local RSV surveillance provides meaningful data to guide decisions on the administration of palivizumab. Reliance on current AAP guidelines for RSV prophylaxis would result in under-protection of at-risk children in all regions within the state of Florida.