Diameter Of Isthmus Research Articles

Three-Dimensional Analysis of the Characteristics of the Femoral Canal Isthmus: An Anatomical Study.

Purpose. To establish a new approach for measuring and locating the femoral intramedullary canal isthmus in 3-dimensional (3D) space. Methods. Based on the computed tomography data from 204 Chinese patients, 3D models of the whole femur and the corresponding femoral isthmus tube were reconstructed using Mimics software (Materialise, Haasrode, Belgium). The anatomical parameters of the femur and the isthmus, including the femur length and radius, and the isthmus diameter and height, were measured accordingly. Results. The mean ratio of the isthmus height versus the femoral height was 55 ± 4.8%. The mean diameter of the isthmus was 10.49 ± 1.52 mm. The femoral length, the isthmus diameter, and the isthmus tube length were significantly larger in the male group. Significant correlations were observed between the femoral length and the isthmus diameter (r = 0.24, p < 0.01) and between the femoral length and the isthmus height (r = 0.6, p < 0.01). Stepwise linear regression analyses demonstrated that the femoral length and radius were the most important factors influencing the location and dimension of the femoral canal isthmus. Conclusion. The current study developed a new approach for measuring the femoral canal and for optimization of customer-specific femoral implants.

Impact of antenatal echocardiography and prognostic factors for postoperative outcome in infants with aortic coarctation of the aorta

This study was to: 1) analyze impact of antenatal echocardiography, 2) assess pronostic factors of outcome, in neonates and infants with coarctation of aorta (COA). Single-center analysis of clinical and echocardiographic data of fetus with suspicion of, and neonates and infants < 1 year of age with COA. Groups DAN (antenatal diagnosis) and DPN (postnatal diagnosis) were compared. 286 cases were included, 106 in DAN group and 180 in DPN. Among 106 antenatal suspected COA, 11 were not confirmed after birth (sensitivity = 34.5%). Antenatal ascending aorta diameter (AAO) and AO/PA ratio were predictors of postnatal COA. Heart failure (HF) was the main symptom in DPN group, absent in DAN ( P < 0.0001). Antenatal echocardiography was associated with lower diameter of isthmus (AOI), transverse arch (TrAO) and AAO. DPN had lower LV systolic fraction (LVSF) than DAN. Preoperative HF was associated with narrowest AOI, AAO, TrAO and decreased LVSF. PGE was administred in 53% preoperatively and mechanical ventilation in 39%. Among 275 confirmed COA (95 DAN and 180 DPN), 272 underwent Crafoord operation, at mean age 29 days (median 12 days) and mean time after admission 3.4 days. Age at surgery was lower and time to surgery longer in DAN than DPN group. Residual postoperative aortic gradient was observed in 18 cases (6.7%), and spontaneously disappeared in the majority of them within 2 postoperative days. Median hospital stay was 11 days. Survival was 98.5%. Restenosis occurred in 20 cases(7%), was related to postoperative AOI diameter and gradient, and AAO, and was more frequent in patients < 1 month at surgery (8.5%). Mortality was associated with Shone complex and parachute mitral valve ( P < 0.0001), LV diameters ( P = 0.02), ICU stay ( P < 0.0001), hospital stay ( P = 0.02). Antenatal diagnosis impacts on early outcomes of neonates with COA. Postoperative isthmus diameter and gradient, and < 1 month age at surgery impact on restenosis.

Percutaneous angioplasty used to manage native and recurrent coarctation of the aorta in infants younger than 1 year: immediate and midterm results.

Balloon angioplasty (BAP) used to manage native coarctation of the aorta (CoAo) in infants remains controversial. This study aimed to compare short- and midterm results of BAP between native CoAo (NaCo) and postsurgical recoarctations (ReCo) in infants younger than 1 year. This retrospective study compared the clinical, echocardiographic, hemodynamic, and angiographic data for infants who underwent BAP between July 2003 and September 2012. The 12 NaCo and 13 ReCo patients in this study underwent BAP at 4.61 ± 3.69 and 4.88 ± 3.07 months (p = 0.84) and weighed 5.49 ± 2.57 and 6.10 ± 2.11 kg (p = 0.52), respectively. Their respective heights were 60.58 ± 10.58 and 61.15 ± 6.74 cm (p = 0.87). All the ReCo patients had their initial surgery before the age of 3 months. The minimal CoAo diameter was 2.81 ± 0.96 mm in the NaCo group and 2.86 ± 1.0 mm in the ReCo group (p = 0.90). The relative gradient reduction was 62.79 ± 32.43 % in the NaCo group and 73.37 ± 20.78 % in the ReCo group (p = 0.33). The in situ complication rate (pseudoaneurysm) was 8.33 % in the NaCo group and 7.69 % in the ReCo group (p = 0.74). During the early follow-up evaluation, five NaCo patients (41.66 %) presented with recoarctation requiring BAP reintervention within 1.75 ± 1.41 months (all had their initial BAP before 3 months of age) compared with 1 ReCo patient (7.69 %) (p = 0.165). The mean follow-up period was 3.09 ± 2.69 years for the NaCo patients and 3.6 ± 3.18 years for the ReCo patients (p = 0.69), during which the blood pressure gradient was 12.33 ± 9.67 for the NaCo patients and 7.80 ± 8.78 for the ReCo patients (p = 0.17), with corresponding Doppler peak instantaneous gradients of 21.29 ± 11.19 and 16.20 ± 10.23 (p = 0.24). The resultant diameter ratio between the minimal isthmus diameter and the aortic diameter at the diaphragmatic level was 0.81 ± 0.15 in the NaCo group and 0.85 ± 0.12 in the ReCo group (p = 0.53). The immediate and midterm results of BAP for the NaCo and ReCo infants were comparable. Accordingly, BAP seems to be an acceptable alternative to surgery for infants older than 3 months.

GW24-e3700 The analysis of Fetal echocardiographic reference value and study on relationship of these measurements with gestational age (I)

ObjectivesTo establish normative reference ranges of fetal cardiac dimensions between 20 and 34 per weeks including: inner diameter of fetal heart and arteries, aortic arch isthmus, descending aorta, ducts artery...

Prediction of coarctation of the aorta in the second half of pregnancy

To determine which combination of cardiac parameters provides the best prediction of postnatal coarctation of the aorta (CoAo) in fetuses with cardiac asymmetry. We selected all cases of disproportion of the ventricles and great vessels prenatally diagnosed between 2003 and 2010 at the Hospital Universitario '12 de Octubre', Madrid, Spain. Only appropriate-for-gestational age liveborn fetuses with isolated cardiac asymmetry and with complete postnatal follow-up were included in the study. Eighty-five cases were retrieved and analyzed. Logistic regression analysis was used to select the best predictors of CoAo. Optimal cut-offs for these parameters were identified and the corresponding likelihood ratios used to calculate the post-test probability of CoAo in each fetus. CoAo was confirmed in 41/85 neonates (48%). The parameters selected by logistic regression and their cut-off values were: gestational age at diagnosis ≤ 28 weeks, Z-score of diameter of the ascending aorta ≤ -1.5, pulmonary valve/aortic valve diameters ratio ≥ 1.6 and Z-score of the aortic isthmus diameter in the three vessels and trachea view ≤ -2. We divided the study group into two subgroups: Group A, in whom the diagnosis was made at ≤ 28 weeks' gestation (80% CoAo (32/40)); and Group B, in whom the diagnosis was made at > 28 weeks (20% CoAo (9/45)). The mean post-test probabilities of CoAo were higher in fetuses with CoAo than in normal fetuses in both subgroups (Group A, 82 vs 55%; P = 0.002 and Group B, 51 vs 20%; P < 0.001). In addition, a rate of growth of the aortic valve of ≤ 0.24 mm/week provided 80% sensitivity and 100% specificity for predicting CoAo in Group A. We have derived a multiparametric scoring system, combining size-based cardiac parameters and gestational age at diagnosis, which may improve the accuracy of fetal echocardiography for the stratification of the risk of CoAo. The objectivity and simplicity of its components may allow its implementation in fetal cardiology units.

En-bloc femoral cement removal after failure of cemented total hip replacement in two dogs

In two dogs with periprosthetic infection after total hip replacement, the femoral cement mantle was retrieved by proximal extraction without an invasive osteotomy or cortical fenestration. En-bloc femoral cement removal was performed by injection of polymethylmethacrylate cement into the central mantle void left after stem removal, and by threading a positive profile pin into the newly injected cement. Once the PMMA had polymerized, the pin was withdrawn with the entire mantle attached. This technique should be considered in patients with circumferential deterioration of the femoral bone-cement interface in which the diameter of the femoral isthmus would not obstruct withdrawal of the cement mantle.

Echocardiographic predictors of coarctation of the aorta

Echocardiography is the main diagnostic modality of coarctation of the aorta especially in infants less than 3 months. Sometimes it is difficult to diagnose coarctation of the aorta either because of poor echo window or because of the presence of a large PDA. Failure or delay in the diagnosis of coarctation will lead to morbidity as well as mortality. The objectives of our study were to look for echocardiographic predictors of coarctation of the aorta. During the period from September 2010 to July 2011 echocardiographic measurements were performed for 67 normal infants referred for echocardiography. This was compared with 37 patients with proved coarctation either by surgery or cath. Echocardiographic measurements performed in both groups include aortic annulus, ascending aorta diameter, proximal transverse arch diameter, distal transverse arch diameter, aortic isthmus diameter, distance between aortic arch branches. Aortic valve anatomy , associated findings as well as surgical and cath diagnosis were reviewed. The ratio between the transverse arch and ascending aorta as well as between transverse arch and the distance between aortic arch branches were calculated. We compared both groups using SPSS statistical software. Measurements were done online as well as offline. During the study period 67 normal infants and 37 infants with coarctation were reviewed. The age group were from one day to one year and the mean weight were 4.48 ± 1.67 and 3.8 ± 2.19 kg for the normal and abnormal groups, respectively. There were no statistical difference between the two groups regarding the age weight as well as the gender. There were statistical difference in the echocardiographic measurements between the two groups regarding the transverse arch diameter with a smaller diameter in the CoA group (3.89 ± 1.17 vs 5.8 ± 1.05 mm, P value 0.0001). The ratio between the transverse arch and the ascending aorta was smaller in patients with CoA (0.55 ± 0.16 vs 0.73 ± 0.16, P value 0.0001). The distance between the left common carotid and the left subclavian arteries was longer in patients with CoA compared to those with normal arch (4.76 ± 2.37 mm vs 2.85 ± 1.59 mm, P value 0.0012). The ratio between the distance between the left common carotid and the left subclavian arteries to that of the transverse aortic arch diameter was higher in patients with Co (1.3311 ± 0.71 vs 0.54 ± 0.29, P value 0.0001). Bicuspid aortic valve was found in 57% of patients with CoA compared to only 6.5% of patients without coarctation (P value 0.0001). Echocardiographic predictors of coarctation of the aorta include the presence of bicuspid aortic valve, hypoplasia of the transverse arch, smaller ratio between the transverse arch and the ascending aorta and high ratio between the distance between aortic arch branches and transverse aortic arch.

Biomechanical consideration of total hip arthroplasty following failed fixation of femoral intertrochanteric fractures – A finite element analysis

ObjectiveThe current study aimed to perform a biomechanical analysis of the effect and distribution of stress and strain values in the femur and its residual screw holes from the implantation of different lengths of total hip prostheses following failed dynamic hip screw (DHS) fixation of AO type A1.1 and A1.3 intertrochanteric fractures. MethodsMedical image processing, computer-assisted engineering design, and finite element analysis were combined for the analysis and the reliability of the model confirmed by convergence testing and comparison with a physical model. Using finite element analysis, patterns of stress from implantation of total hip prostheses with different stem length were obtained. ResultsStress distribution was concentrated over the third and fourth residual screw holes, especially in the models with shorter stem length. Fracture type (AO type A1.1 or A1.3) did not alter its distribution. In proximal cancellous bone, a stress-shielding effect was seen at the region of the residual fracture fragment, especially in the A1.1 fracture. In the fracture fixed with 2 cable wires, the maximum von Mises stress was in the proximal cable wire. ConclusionThe results suggest that an increase in the original stem length equal to the diameter of the femoral isthmus, or a distance between the most distal residual screw hole and the end of the femoral prosthesis, provide improved stress distribution.

Effects of Frontal Recess Cells on the Development of Frontal Sinusitis

Background and ObjectivesZZFrontal recess anatomy can be very complex, with accessory cells extending to the frontal sinus and possibly contributing to the obstruction of the frontal sinus. However, there is still controversy on the effect of the frontal recess cells. We designed this study to assess the effect of frontal recess cells on frontal sinusitis. Subjects and MethodZZWe retrospectively reviewed chart and collected data of those who visited the outpatient clinic between January and June, 2011. Parnasal sinus CT was taken with Brillance 64-slice computed tomography scanners. The image was reviewed by two or more otolaryngologists to identify the frontal recess cells. The nasofrontal isthmus diameter and the area of nasofrontal isthmus was reconstructed and measured with workstation. Then, we compared the radiological results of frontal recess cells with the frequency of frontal sinusitis. ResultsZZThe presence of anterior group of frontal recess cells showed no influence on the frontal recess anatomy. The presence of frontal bullar cell was significantly associated with the development of frontal sinusitis by simple (p=0.001) and multiple (p=0.038) logistic regression models. It was shown that the narrower the area of frontal isthmus the more developed were the frontal sinusitis, showing statistically significance in the simple (p=0.013) and multiple (p= 0.017) logistic regression models. ConclusionZZOur results also showed that similar results compared to previous Asianreport. The narrowness of nasofrontal isthmus could be the cause of frontal sinusitis. The frontal bullar cell could be the cause of frontal sinusitis encroaching on the frontal recess and affect the nasofrontal pathway.�

The development of the aortic isthmus in human fetal life

Abstract Introduction The aortic isthmus is a specific feature of fetal circulation. It undergoes regression by becoming wider postpartum. Developmental abnormalities of an isthmus may lead to congenital defects. Aim The aim of this work was a morphometric study of the aortic isthmus in human fetuses aged between 4 and 8 months of fetal life. Materials and Methods We investigated 223 human fetuses, including 108 males and 115 females, aged between 4 and 8 months of fetal life. The entire material was obtained from the Department of Histology and Embryology at the Collegium Medicum, Nicolaus Copernicus University in Bydgoszcz, Poland. All fetal specimens had been conserved in a 9% formaldehyde solution for a period of more than 3 months. Only spontaneously aborted fetuses with a normal morphology and a normal karyotype were used in this study. We investigated the diameter of the aortic isthmus in human fetuses at different stages of prenatal life. We also analyzed the ratio of that diameter with regard to the diameters of other segments of the aorta and ductus arteriosus. We considered how these measurements varied depending on sex. Results, Discussion and Conclusions We found the growth of the aortic isthmus diameter to be linear in time. The measured diameters were similar in males and females. No significant differences with regard to sex were found between the ratios of that vessel's diameter to the diameters of the ascending and descending aorta and the ductus arteriosus. The relative ratio of the aortic isthmus diameter to the diameters of the ascending and thoracic aorta decreased with time. On the contrary, the ratio of the aortic isthmus diameter to the ductus arteriosus diameter increased over time.

Ring and Little Finger Metacarpal Fractures: Mechanisms, Locations, and Radiographic Parameters

To describe a series of ring and little finger metacarpal fractures with regard to mechanism, location, midshaft diameter, and isthmus diameter, to better define injury patterns and assist the surgeon in selection of appropriately sized implants. We reviewed all metacarpal fractures in skeletally mature patients who presented to a single surgeon over a 2-year period. Fractures of the ring and little finger metacarpals were analyzed with regard to mechanism and fracture location. Metacarpal midshaft and minimum isthmus diameters were measured on posteroanterior radiographs. A total of 101 fractures involved the ring and little finger metacarpals. Punching-type injuries accounted for most fractures in the little finger metacarpal (49 of 67) and ring finger metacarpal (26 of 34). Among these punching-related ring and little finger metacarpal fractures, the most common fracture location was the little finger metacarpal neck (34 of 75), followed by the ring finger metacarpal shaft (21 of 75). Among men in this series, the metacarpal midshaft and minimum isthmus diameters were significantly narrower in the ring finger metacarpal than in the little finger (7.4 vs 8.7 mm, p < .001; and 2.2 vs 3.8 mm, p < .001). Whereas punching injuries tended to cause neck fractures in little finger metacarpals in this series, they caused shaft fractures in ring finger metacarpals, which may thus be considered a variant boxer's fracture. Furthermore, in men with fractures, the ring finger metacarpal is significantly narrower than the little finger, both in midshaft diameter and isthmus diameter, which surgeons should consider when planning internal fixation. Prognostic IV.

Anatomical Considerations for Subaxial (C2) Pedicle Screw Placement

Radiographic study. More detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial computed tomography. Although earlier studies have analyzed the anatomy of the C2 pars interarticularis, little attention has been focused on the dimensions of the C2 pedicle. Ninety-three patients (47 males, 46 females; mean age 48.4 y) who had previous cervical spinal computed tomography imaging were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, ie, the angle between the pedicle axis and the midline of the vertebral body). The overall mean pedicle width was 5.8+/-1.2 mm. The mean pedicle width in male patients (6.0+/-1.3 mm) was greater than that in the female patients (5.6+/-1.1 mm). This difference was not found to be statistically significant (P=0.679). The overall mean PTA was 43.9+/-3.9 degrees. The mean PTA in male patients was 43.2+/-3.8 degrees, whereas that in female patients was 44.7+/-3.7 degrees. Given the significant variability in pedicle widths and the need for precise trajectory planning in pedicle cannulation, preoperative planning is absolutely mandatory. A significant percentage of patients have pedicle widths that may not accommodate screw fixation. In addition, the angle of entry into the C2 pedicle must be carefully measured for safe instrumentation at this level.

Preoperative Radiographic Factors and Surgeon Experience Are Associated With Cortical Breach of C2 Pedicle Screws

A retrospective review study. In this study, we attempt to identify radiographic variables associated with likelihood of intraoperative breach during C2 pedicle screw placement. In addition, we attempt to correlate surgeon experience with breach rate. Pedicle screws have emerged as an effective approach for obtaining fixation of the axis, yet placement of C2 pedicle screws is technically demanding and poses the risk of injury to the vertebral artery. Given the evidence for substantial variation in C2 anatomy, preoperative assessment of computed tomography (CT) scans may indicate, which patients are at increased risk for cortical breach during the pedicle screw placement. A retrospective review of all patients undergoing C2 pedicle screw fixation at a single institution over the last 6 years was conducted. Radiographic cortical breaches were defined on postoperative CT scans as visualization of the screw beyond the cortical edge. Radiographic measurements were determined from preoperative CT scans and were then correlated with breaches via Student t test. The association of breach rate with surgeon experience was evaluated using univariate linear regression. Ninety-three patients underwent placement of 170 screws. Cortical breach was detected on postoperative CT scans in 43 screws (25.3%). One clinically significant breach occurred with damage to the left vertebral artery intraoperatively. On axial CT sections, mean pedicle isthmus diameter was significantly smaller in patients with breach than in patients without breach for both left and right sides, P=0.006 and P=0.010, respectively. Specifically, a diameter of less than 6 mm was associated with a nearly 2-fold increase in risk of cortical breach (37% vs. 21%). Surgeons with greater experience in placing C2 pedicle screws were noted to have a lower breach incidence (P=0.004). During placement of C2 pedicle screws, likelihood of cortical breach may be associated with size of pedicle and surgeon experience. Extensive preoperative evaluation of CT scans and consideration of technical demands of procedure may help avoid complications with such internal fixation.

Fetal Aortic Arch Measurements at 14 to 40 Weeks' Gestation Derived by Spatiotemporal Image Correlation Volume Data Sets

The purpose of this study was to establish reference ranges for the transverse aortic arch diameter (TAD) and distal aortic isthmus diameter (DAID) in normal singleton pregnancies (14-40 weeks) based on the 3-vessel/trachea (3VT) view of cardio-spatiotemporal image correlation (STIC) volume data sets. A prospective descriptive study was conducted on uncomplicated singleton pregnancies with healthy fetuses and an accurate gestational age (GA). Cardio-STIC examinations were performed by experienced sonographers using a high-resolution ultrasound machine, and the volume data sets were manipulated to obtain the 3VT view and measured for the TAD and DAID. A total of 554 measurements were performed, ranging from 13 to 30 for each gestational week. The best regression models were as follows: TAD (in millimeters) = -1.01 + 1.69 (GA, in weeks) (r(2) = 0.93; P < .001), and DAID (in millimeters) = -0.85 + 1.54 (GA, in weeks) (r(2) = 0.92; P < .001). A table of nomograms for 5th, 50th, and 95th percentile ranges was constructed. Normative data for the TAD and DAID at each gestational week from 14 to 40 weeks were constructed by a new technique of measurement based on cardio-STIC. These reference ranges may be useful tools for assessment of fetal aortic arch abnormalities.

Anatomical considerations for cervical pedicle screw insertion: the use of multiplanar computerized tomography measurements in 122 consecutive clinical cases

Background context Successful placement of pedicle screws in the cervical spine requires a sufficient three-dimensional understanding of pedicle morphology to allow accurate identification of the screw axis. Purpose The goal of the present study was to assess morphologic trends from one level to the next with respect to linear and angular parameters associated with the subaxial cervical pedicles. Study design/setting We evaluated the pedicle morphology of cervical spine using axial and sagittal computed tomography (CT) imaging. The C3–C7 vertebrae in 122 patients (610 vertebrae) were evaluated (age range, 14–93; mean, 48 years). Methods Thin cut (2.5 mm thickness) axial CT images were measured. Sagittal reconstructions were obtained using 1.25-mm thickness slices. The following pedicle parameters were assessed: pedicle width (PW, the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis), pedicle height (PH, rostro-caudal dimension of the pedicle determined on the sagittal image), maximal screw length (MSL, distance from the posterior cortex of the lateral mass to the anterior wall of the vertebral body along the pedicle axis), and pedicle transverse angle (PTA, angle between the pedicle axis and the midline vertebral body). Results The overall mean PW and PH ranged from 4.7 to 6.5 mm and 6.4 to 7.0 mm, respectively. For both these parameters there was a trend toward increasing size proceeding caudally in the cervical spine. The mean PW and PH was greater in males than in females, and this difference was statistically significant at all levels (p<.0001). The overall mean MSL ranged from 29.9 to 32.9 mm. All intersections of the pedicle axis and the posterior cortex of the lateral mass were located at the most lateral portion of the lateral mass for the C3–C6 vertebrae. The overall mean PTA ranged from 37.8° to 45.3°. The overall mean PTA was approximately 44° from C3 to C6 and 37.8° at C7. Conclusion The findings of our radiological anatomical study suggest that the preoperative CT scans of patients undergoing cervical transpedicular fixation should be thoroughly analyzed and close attention paid to the pedicle size and its angulation. The placement of cervical pedicle screws should be individualized for each patient and based on detailed preoperative planning.

Evaluation of the Diameter of the Proximal Descending Thoracic Aorta with Age: Implications for Thoracic Aortic Stent Grafting

Long-term anatomical changes of the thoracic aorta which may affect long-term outcome of blunt aortic injuries treated with endovascular stent grafts are unknown. The purpose of this study was to examine the natural history of thoracic aortic diameter with progressing age. One thousand consecutive thoracic computed tomographic scans performed for nonthoracic aortic pathology on patients aged 15-99 (mean 59.4) were examined, and thoracic aortic diameter immediately adjacent to the left subclavian artery was measured. Factors possibly influencing diameter, including age by decade of life, race, gender, history of hypertension (HTN), diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), and tobacco use, were examined. Factors were compared using Student's t-test. The differences in mean diameters of the thoracic aorta by gender (male=27.1 vs. female=26.0, p=0.87), race (Caucasian=26.6 vs. non-Caucasian=26.3, p=0.10), presence of HTN (yes=25.8 vs. no=24.9, p=0.36), COPD (yes=26.3 vs. no=25.4, p=0.21), DM (yes=26.1 vs. no=25.3, p=0.12), and tobacco use (yes=26.3 vs. no=25.0, p=0.18) were not significant. However, differences in mean diameter increased significantly over time with age. Patients under 40 years old had mean aortic diameters of 22.92 mm compared to 27.09 mm (p<0.001) for patients over 40. The mean aortic isthmus diameter showed an approximately 1cm increase when comparing octogenarians to teenagers. The diameter of the aortic isthmus increases substantially with age. These findings suggest that long-term surveillance is warranted for trauma patients with aortic stent grafts, to monitor the natural history and to assess for possible late complications.

Anatomic considerations for C2 pedicle screw placement: the use of computerized tomography measurements

OBJECTIVE: more detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial CT. METHODS: ninety three patients (47 males, 46 females mean age 48 years) who had cervical spinal CT imaging performed were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (PW, the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, that is, the angle between the pedicle axis and the midline of the vertebral body). RESULTS: the overall mean pedicle width was 5.8 1.2mm. The mean pedicle width in males (6.01.3mm) was greater than that in the female subjects (5.6 1.1mm). This difference was not found to be statistically significant (p=.6790). The overall mean pedicle transverse angle was 43.93.9 degrees. The mean PTA in males was 43.23.8 degrees, while that in females was 44.73.7 degrees. CONCLUSION: preoperative planning is absolutely mandatory, particularly in determining not only screw trajectory, but in analyzing individual patient anatomy and reception to a C2 pedicle screw.

Population-related differences in fetal aortic arch dimensions

Diagnosing fetal aortic arch anomalies, such as coarctation of the aorta (COA), is difficult. Hornberger et al. [1] constructed nomograms of the normal development of the aortic arch to help detect anomalies by comparing sonographic images with the nomograms for the same gestational ages. However, these graphs are not always reliable across populations. For instance, our measurements of the distance between the mitral and tricuspid valves in growing Thai fetuses differed from those published in a Western study [2]. We are reporting on how we constructed nomograms of the fetal aortic arch in growing Thai fetuses using the transverse aortic arch diameter (TAD) and the distal aortic isthmus diameter (DAID), and evaluated the nomograms' helpfulness in detecting fetal aortic arch anomalies in the Thai and other populations. We also report on the differences between these Thai nomograms and those constructed by Hornberger et al. in the United States [1]. We conducted this work from January to September 2007 with 294 women whose pregnancy duration was accurately known. None of the 20to 40-week fetuses had structural anomalies. Ultrasound exploration was done once in each participant using an Aloka model SSD Prosound 5000 (Aloka, Tokyo, Japan) or a Voluson 730 Expert (GE Medical Systems, Waukesha, Wisconsin, USA). With the arch viewed in the long axis, TAD was measured between the common carotid and the left subclavian arteries and DAID was measured distal to the origin of the left subclavian artery, both during the ventricular systole. The mean values of 3 measurements were calculated and plotted against gestational age. Correlation coefficients were determined using the Pearson correlation. The TAD and DAID measurements presented are the 5th, 50th, and 95th percentile (Table 1). Using the Mann-Whitney U test, we compared echocardiographic findings for 5 fetuses with COA obtained between the 22nd and 38th weeks of gestation to our nomograms. We also compared our nomograms to those published in the report by Hornberger et al. [1] using the Z test. The following regression equations were found to have the best fit:

889 Hypoplastic left heart syndrome: the role of cardiac STIC in prenatal diagnosis

889 Hypoplastic left heart syndrome: the role of cardiac STIC in prenatal diagnosis

Quantitative evaluation of aortic arch development using digital-image analysis

This study was performed on 80 spontaneously aborted human fetuses of a gestational period of between 17 and 27 weeks. The procedure was based on latex filled arteries, which were preserved in formalin, and then later dissected. Data collection was accomplished using digital imaging. The specific measurements of the aortic arch diameter, length and volume were obtained using a computer program, written solely for the purpose of this study. Results indicated that the collected figures correlated with the fetal age through 3 sets of 4-week intervals. Diameter and length of the aortic arch varied from 2.5 to 4.1 mm and from 6.7 to 10.3 mm, respectively. Both parameters showed statistically significant (p<0.05) linear growth and differences between age groups. The volumetric growth of the aortic arch followed a square root function with its values ranging from 35.7 to 136.8 mm3, which were also statistically significant (p < 0.05). The diameter of the aortic isthmus was measured and compared to the diameters of the ascending and descending aorta thus allowing an estimation ratio between those parameters. Concluding analyses suggest that the aortic isthmus becomes narrower during fetal development.