Characteristics of sudanese camel-hair fibres under subtropical desert condition.

The study assessed the quality and variability of camel hair fibres in arid regions of Egypt. Raw camel-hair samples were collected from fifteen Sudanese camels divided into seven males (414.60 ± 38.19 kg, BW) and eight females (401.67 ± 26.76 kg BW), and the study investigated the influences of animal sex on both the physical and chemical traits of camel-hair fibers. The relationships among physical properties and both mineral and amino acid content were studied. Camel's sex had no significant effect on any of the studied traits including fibre diameter (FD), prickle factor (PF), medullated fibre (MF), staple length (SL) and staple strength (SS). In the meantime, no significant differences were found between males and females in fibers' minerals contents except potassium, where fibres of females had significantly higher potassium content than those of males. For amino acids contents in camel fibres, camel sex had a significant effect only on glutamic acid, since fibres of males showed higher (P < 0.05) content than females. Fibre diameter had positive (P < 0.01) correlations with prickle factor (r = 0.83) and medullated fibres (r = 0.73). Zinc content in camel fibres was positively correlated with fibre diameter (r = 0.57; P < 0.05) and medullated fibres (r = 0.73; P < 0.01). Moreover, a significant (negative correlation coefficient P < 0.05) was found between fibre diameter and both sulfur and proline contents (r=-0.39 and - 0.56). Ammonia content in fibres was correlated negatively (P < 0.05) with prickle factor and elongation (r=-0.62 and - 0.58, respectively). The variability in the physical properties and chemical composition of Sudanese camel-hair fibers under subtropical desert conditions may shed light on the possibility of improving fiber quality.

Ability of the objective structured clinical examination to differentiate surgical residents, medical students, and physician assistant students.

BACKGROUND: The Objective Structured Clinical Examination (OSCE) has been used extensively to evaluate the clinical abilities of medical students and residents. The purpose of this study was to investigate whether the standard OSCE would differentiate performance of subjects with different levels and/or types of training. METHODS: We conducted a blinded OSCE, during which we simultaneously evaluated surgical residents from all 5 years of the general surgery training program, third-year medical students, and second-year physician assistant students. All examinees went through the same clinical evaluation stations, which consisted of history-taking, physical examination, technical skills, trauma management, and X-ray interpretation. The students and residents were rated at each station by a trained standardized patient evaluator or a faculty evaluator using a checklist for performance evaluation. All subjects wore surgical scrubs without name tags or identification of program or year of training. RESULTS: Overall mean performance scores (P = 0.09, NS) were for surgical residents 71.2% (+/-9.7); for medical students 66.9% (+/-5.7); for physician assistant students 64.7% (+/-5.8). This shows a significant trend toward higher scores with more training. Surgical residents scored higher on technical stations, history-taking, and X-ray interpretation. Medical students scored higher in performance of physical examination. Physician assistant students scored quite close to the other two groups. CONCLUSIONS: The differences among group performance appeared to reflect the level of experience of the learners. Some components of the OSCE appear to better differentiate levels of training.

Radiographic evaluation of transverse sacral fractures.

This study clarifies the pattern of fracture lines and facilitates diagnosis of transverse sacral fracture on plain radiographic images. Eight cadaveric sacra were used in this study. A U-shaped transverse sacral fracture at the S2-S3 level was created in all specimens. The fracture line was marked by painting with radio-opaque material and solder metal wires. The following radiographic views were taken: anteroposterior, lateral, AP with 35 degrees cephalad orientation, and inlet view. A double shadow in the upper sacral area can be identified in the plain AP view. As a consequence of the fracture, there are changes in the orientation of the planes of the foramina from the coronal to, more or less, axial plane. Anteroposterior with 35 degrees cephalad orientation radiographs provide good assessment for evaluation of the transverse sacral fracture.

Bone density of the first sacral vertebra in relation to sacral screw placement: a computed tomography study.

A visual three-dimensional image of the first sacral vertebra was constructed using computer software to predict the sites of strong density for better screw purchase of upper sacrum. Forty dry sacrum specimens were scanned in the prone position. An axial section, 10 mm below the S1 end plate, was selected for determining density at the region of interest. All images were stored on an optic disc and studied using the NIH Image 1.61 program. Plot analysis assessed the bone density in different regions. Also, three-dimensional pictures of the different screw paths and the related bone density in the upper sacrum were analyzed. Bone density in the anterolateral part of S1 was 115.1 +/- 10.4 pixel. Bone density for males (-99.7 +/- 11.3) was greater than for females (-131.4 +/- 9.6). Bone density in the anterolateral alar region was -108 +/- 10.6. The bone density for males (-95.6 +/- 9.8) and females (121.4 +/- 11.7) was more than the body region. Bone density in the middle anterior cortex of the ala was 759.8 +/- 11.6. Bone density for males (878.2 +/- 10.7) was greater than for females (637.6 +/- 11.9). Using surface plot, the midanterior cortex of the ala had high cortical density compared with other areas. The midanterior cortex of the sacral ala had the highest bone density. Sacral screw purchase in the midanterior cortex provides better mechanical fixation.

Assessment of distal radial articular surface by angled radiography.

A common complication of surgical management of fractures of the lower radius involves hardware penetration of the articular surface. If neglected, this complication will lead to wrist joint degeneration. The authors of this study describe a plain roentgenographic angled view of the wrist that provides visualization of the distal radial articular surface to detect any hardware penetration. This view can also be used during surgery by means of an image intensifier.

Congruity of the subtalar joint in tongue fracture of the calcaneus: an anatomical study.

STUDY DESIGN: An anatomic study. OBJECTIVES: To evaluate the effect of displacement of the fractured posterior facet in tongue fracture of the calcaneus on the congruity of the subtalar joint. METHODS: Eleven feet were used in this study. Seven females and four males with age range from 59 to 78. The specimens were dissected from both the lateral and the medial aspects of the calcaneus to expose these surfaces. A primary fracture line was created first, then a secondary line was engineered to simulate tongue fracture. Displacement of the superio-lateral fragment was done with 5-mm increment. Radiography was performed and the graphs were scanned and studied on specific computer software to explore the effects of displacement on joint congruity. RESULTS: The anterior end of the fragment of the tongue fracture, when displaced, not only is depressed but also rotated in the sagittal plane in a downward or planterward direction. The articular surface of the posterior facet of the calcaneus and the inferior facet of the talus are maintained in congruence with each other despite the varying degree of displacement and rotation. CONCLUSION: Congruity of the subtalar joint in tongue fractures is maintained despite different degrees of displacement. This study explains why the non-surgical treatment outcome is comparable to that of the operative treatment in tongue fractures of calcaneus. It also explains why tongue fractures have a good outcome with closed reduction.

Occipital screws in occipitocervical fusion and their relation to the venous sinuses: an anatomic and radiographic study.

This study examined the safe zone for placement of occipital screws without endangering the sinuses. In the first part of the study, 10 cadaveric skulls were exposed. The borders of the confluences and the transverse sinuses were located on the outer table of the occiput. In the second part of the study, six cadaveric skulls were used and screws were placed in different sites and angiography of the venous sinuses was performed. The exact location of the venous sinuses on the outer table of the occiput were analyzed. The examination of the relationship between occipital screws placed at different sites and the venous sinuses clearly demonstrated that whenever the screws were inserted at the level of the external occipital protuberance, or 1 cm below it, sinus injury could rarely be avoided. To enhance the safety of the occipitocervical fusion, the external occipital protuberance should be avoided, and occipital screws should be placed at least 2 cm below the superior nuchal line.

Calcaneus fractures with subluxation of the posterior facet. A surgical indication.

The charts and radiographs of 118 patients with 126 intraarticular fractures of the calcaneus were reviewed retrospectively. Eleven of 126 (8.7%) calcaneal fractures had injuries consisting of intraarticular calcaneal fracture, lateral subluxation or dislocation of the posterior facet, fracture extension into the calcaneocuboid joint, peroneal tendon subluxation, subluxation of the talus in the ankle mortise, and complete disruption of the anterior talofibular and calcaneal fibular ligaments or fracture of the lateral malleolus. There were six women and five men. The average age was 40 years (range, 17-65 years). The mechanism of injury was a motor vehicle accident in eight and a fall from a height in three. According to the classification of Sanders et al eight fractures were Type II, one was Type III, and two were Type IV. Followup at an average of 26 months (range, 14-38 months) showed that eight of 11 patients (72.7%) had either good or excellent results. When lateral subluxation of the posterior facet of the calcaneus is identified with a preoperative computed tomography scan, operative management is indicated, and the surgeon should search for associated injuries that should be addressed at the time of surgery.

Computed tomography in the determination of transarticular C1-C2 screw length.

This study evaluated the significance of computed tomographic (CT) measurements of the upper cervical vertebrae and their clinical implications in transarticular C1-C2 screw placement. In the first part of the study, analysis of axial CT scans of the atlas of 46 patients who had a normal C1-C2 region was performed. Measurements included the vertical distance between the middle of the ventral cortex of the lateral mass and the anterior-most point of the anterior tubercle, and the angle of the anterior ring of C1 relative to the frontal plane. In the second part, axial CT scans of the upper cervical spine were performed in seven cadaveric cervical spines and analyzed using the same criteria. Using the Magerl technique of transarticular C1-C2 screw placement, one screw was placed in each cervical spine. Following each placement, a strict lateral radiograph was taken and the distance between the tip of the screw and the anterior-most point of the anterior tubercle of C1 was measured. Analysis of the cervical cadaveric specimens showed the vertical distance between the middle of the ventral cortex and the anterior-most part of the anterior tubercle when measured on CT scan corresponded to the distance measured on lateral radiographs after placement of the C1-C2 transarticular screw. The study of the 46 patients with normal C1-C2 region had shown the mean values of linear and angular measurements to be greater in males than in females, although no significant difference was found between the two groups (P>.05). The mean distance between the anterior-most point of the anterior tubercle and the middle of the ventral cortex of the lateral mass was 6.5+/-1 mm, and the mean transverse angle of the anterior ring relative to the frontal plane was 22 degrees+/-3.1 degrees. Axial CT evaluation of the individual anatomic relationships of the atlas is simple and may be a useful guide in the determination of the length of the transarticular screw when performed during surgery under lateral fluoroscopic control.

Intraoperative imaging of the tibial plafond fracture: a potential pitfall.

STUDY DESIGN: Human tibial plafond cadaveric specimens were coronally sectioned and imaged to assess the accuracy of evaluation of ankle joint line congruity using anteroposterior radiography. Two interesting representative clinical cases are discussed. OBJECTIVES: To evaluate the validity of the routine use of anteroposterior radiographs to evaluate intra-operative ankle joint line congruity in circumstances where lateral radiographs are infeasible due to obscuring internal or external hardware. METHODS: Eleven frozen human cadaveric lower extremity specimens were used in this study. At the level of the tibial plafond, the specimens were sequentially sliced into 0.5cm sections in the coronal plane. True anteroposterior radiographs were taken with the specimen en bloc. Sequentially, the posterior slices were removed one by one, with an image taken after removing each section. The process was then repeated by removing the anterior sections sequentially with intervening radiographs. Each series of anteroposterior radiographs was then evaluated to characterize which portion of the joint line on the whole specimen view had been contributed by each of the sections. This then allowed us to make inferences about the evaluation of the joint line if it had been derived solely by anteroposterior radiography. Two poignant clinical cases demonstrating the clinical relevance of this information are discussed. RESULTS: By sequentially imaging after removing coronal sections of the tibial plafond we were able to accurately characterize the contribution of each portion of the plafond to the overall anteroposterior view. By primarily imaging the anterior portions of the plafond, with the posterior portions removed, the joint line image was virtually unchanged from the en bloc anteroposterior radiograph. However, removal of the anterior coronal sections caused large variation in the joint line image. These observations demonstrate that the anteroposterior radiograph of the tibial plafond characterizes the anterior portion of the joint well, while it represents a poor assessment of the posterior portion of the joint. This was well illustrated in our clinical case presentations. CONCLUSION: In severe fractures of the tibial plafond multiple forms of internal and external devices are frequently used for fixation. In these circumstances hardware may obscure the lateral view making it impossible to obtain adequate lateral radiographs to assess fracture reduction and joint line congruity. In this scenario, the anteroposterior radiograph is frequently relied upon to confirm the anatomic relationship of the displaced fragments. However, this view fails to accurately characterize reduction in the entire joint line and, intra-operatively, may mislead the surgeon to accept a reduction as anatomic when intra-articular incongruity still exists. Strict attention to pre-operative radiographs and the use of additional rotated views may aid the surgeon in this setting to assess fracture reduction and joint line congruence.

Internal architecture of the sacrum in the elderly. An anatomic and radiographic study.

STUDY DESIGN: A description of the internal architecture of the sacrum, including its trabecular arrangement, cortical thickness, and overall bone density. OBJECTIVES: To determine the strong and weak areas in the sacrum to understand more clearly the sacral structure and its clinical implications. METHODS: First, seven cadaveric sacral specimens were sectioned in different planes. Horizontal sections were performed at the upper S1, middle S1, S2, S3, and S4. Sagittal sections were made through the median sacral crest, the sacral foramina, and medial to the articular surface. A coronal section through the whole length of a sacral specimen was produced. All sections were studied radiographically, and the trabecular pattern was analyzed. In the second part of the study, axial computed tomography scans of 40 dry sacrum specimens were analyzed by using the National Institutes of Health Image 1.61 program. The cortical thickness and bone density were determined. RESULTS: In the upper sacrum, three distinctive distributions of bony trabeculae were noted, one extending from the center of the sacral body anterolaterally, and the other two extending from the pedicle toward the auricular surface. A condensation zone was observed at the intersection of these trabeculae and was located at the anterior cortex of the foraminal zone. The junction between S2 and S3 represented a weak area with abrupt disappearance of the condensation zone. Analysis of the bone density of the sacrum using the plot analysis demonstrated that, at S1 and S2, the anterior cortex of the foraminal zone (condensation zone) is the most compact part of the sacrum. CONCLUSION: These results suggest that the strongest part of the sacrum is the anterior cortex above the foramina in S1 and S2. The weakest point of the sacrum was found to lie at the level of the junction of S2 and S3.

Sinus tarsi approach with trans-articular fixation for displaced intra-articular fractures of the calcaneus.

The charts and radiographs of 99 patients with 106 intraarticular fractures of the calcaneus were retrospectively reviewed. There were 75 men and 24 women. The average age was forty-two (range, 17 to 81). Fifty-seven of the fractures were left and 49 were right. The mechanism of injury was a fall from a height in 69 patients and motor vehicle accident in 30 patients. According to Sanders classification, seventy-one cases (67%) had type II fractures, 25 cases (23.6%) had type III, and ten cases (9.4%) had type IV. All the patients had operative management through a limited sinus tarsi approach with minimal fixation of the fracture with one or several pins. One of the pins was usually applied from the talus to the calcaneus through the fracture after reduction of the posterior facet. Nine cases (8.5%) developed postoperative infection, four cases (3.8%) had superficial wound infection, four cases (3.8%) had pin tract infection and one case (0.9%) had osteomylitis. Our follow-up at an average of 29 months (range, 12 to 84 months) showed that the American Orthopedic Foot and Ankle Society, Ankle-Hindfoot Score for the all group was 77.6 (range, 31-91). Forty-one fractures (38.8%) were graded excellent, 39 fractures (36.7%) good, 14 fractures (13.2%) fair, and 12 fractures (11.3%) were failures. Although radiological degenerative changes in the subtalar joint were seen in 41 cases (38.7%), only six cases (5.6%) required subsequent subtalar fusion. The authors conclude that the operative method used in the current study which followed the principle of minimal soft tissue damage and minimal internal fixation may be a good option for management of calcaneus fractures.

Internal architecture of the calcaneus: implications for calcaneus fractures.

STUDY DESIGN: Fourteen cadaveri specimens were sectioned to analyze the internal architecture of the human calcaneus. We described the arrangement and orientation of trabecular patterns within the calcaneus and made multiple measurements of its cortical thickness. OBJECTIVE: To characterize the internal architecture of the calcaneus and correlate these findings with well-described patterns of calcaneus fracture in order to better understand the fracture mechanics of this common fracture. METHODS: Fourteen dry, frozen, human calcanei were sectioned using a saw. In each the coronal, sagittal and axial planes, we sectioned separate specimens into slices of 0.5 mm thickness. High-resolution radiographic images were taken of the sectioned specimens. The internal trabecular arrays were described and measurements of cortical thickness were recorded. The correlation between these findings and the known pattern of calcaneal fractures was analyzed. RESULTS: A dominant trabecular pattern running antero-posteriorly along the long axis of the calcaneus was observed. In the posterior tuberosity the trabeculae were arranged parallel to the posterior border. There was an area of sparse or absent mineralization in the anterior part of the calcaneus corresponding to the "neutral triangle" described by Wood and Harty 10, 23. The thickest sites of the calcaneal cortex were the lower pole of the posterior tuberosity, the upper surface at the angle of Gissane, and the lateral surface below the anterior portion of the posterior facet. CONCLUSION: The trabecular architecture of the calcaneus is created by applied stress in concordance with Wolff's law. The weakest plane of resistance to stress is parallel to these organized trabeculae or through areas lacking trabeculae. This study demonstrates that the primary and secondary fracture lines commonly encountered in calcaneus fractures correlates with the internal architectural map of the calcaneal trabecular patterns.

Internal architecture of the talus: implication for talar fracture.

The internal architecture of the talus has not previously been well described even though the morphological anatomy and the blood supply have been studied extensively. This study describes the internal architecture of the talus regarding its trabecular orientation, using high-resolution x-ray images of 13 dry tali and thick sections in the coronal, sagittal, and axial planes. The trabecular arrays and their relationship to talar fractures are described. The trabecular content of the neck of the talus is less than that of the head or the body. The direction of the trabecula in the neck is different from the orientation of the talar body trabeculae.

Immunoglobulin levels, opsonic activity and phagocytic power in Egyptian thalassemic children.

Serum IgG, IgM and IgA were determined in 25 patients with homozygous beta thalassemia and 7 with the trait. The levels were increased in homozygous patients and increased further after splenectomy. Serum opsonic activity against Salmonella typhi and staphylococci was impaired in homozygous patients. Splenectomy caused more impairment against salmonella only. Similarly, phagocytic power against both organisms was lower in beta thalassemia. Further decrease against salmonella occurred after splenectomy. Patients with thalassemia trait did not differ from normal controls.

Intestinal mucosal changes in thalassaemia major.

Ten infants and children suffering from Thalassaemia major, proven by clinical, hematological and biochemical criteria, were subjected to intestinal biopsy. Specimens were studied for histological and histochemical patterns. The histological picture showed shortening and fusion of villi with cellular infiltration. Reduced mucopolysaccharides and relatively normal alkaline phosphatase activity were demonstrated. The degree of histological and histochemical changes correlates with the degree of anemia. The effects of these changes on the iron absorption and the tissue hemosiderosis are aroused. The possibility of these changes, being non-specific and secondary to anemia and tissue hypoxia is also postulated.

Anthropological studies among Libyans. Erythrocyte genetic factors, serum haptoglobin phenotypes and anthropometry.

Anthropological studies were done on 1276 Libyans from the Mediterranean cities of Tripoli and Benghazi, and from Sabha southward in The Sahara. The incidences of hemoglobin (Hb)-S and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency were low in the coastal areas and significantly high in Sabha. Hb-C occurred sporadically in Tripoli and Sabha, and was absent from Benghazi in the east. One case of Hb-J Benghazi was noted. There were no sigificant differences in the ABO blood group and Rh0 (D) type distributions in the three localities. G-6-PD gene GdAfrequency was significantly high in Sabha. The lowest value of 6-phosphogluconate dehydrogenase (6-PGD) gene PGDA frequency and highest value of the gene PGDC were in Sabha. Adenylate kinase (AK) gene AK2 was only detectable in Tripoli. Acid phosphatase (AP) gene Pa frequency in Sabha was more than twice that in Tripoli and Benghazi, while pc was distinctly lower in Sabha than in the northern cities. Haptoglobin gene Hp1 frequency was almost identical in all areas. Anthropometric measurements revealed overall homogeneity of the three samples, closer similarity in the coastal region to adjacent North African populations, and Negroid influence in the Sahara Libyans. Anthropometry substantiated findings from blood markers.