Biomedical subjects

N A Ebraheim

Publications and source records attributed to N A Ebraheim.

At least 19 recordsLinked to original sources

PubMed2006

Three-dimensional volume rendering of tibiofibular joint space and quantitative analysis of change in volume due to tibiofibular syndesmosis diastases.

OBJECTIVE: The diagnosis of ankle syndesmosis injuries is made by various imaging techniques. The present study was undertaken to examine whether the three-dimensional reconstruction of axial CT images and calculation of the volume of tibiofibular joint space enhances the sensitivity of diastases diagnoses or not. DESIGN: Six adult cadaveric ankle specimens were used for spiral CT-scan assessment of tibiofibular syndesmosis. After the specimens were dissected, external fixation was performed and diastases of 1, 2, and 3 mm was simulated by a precalibrated device. Helical CT scans were obtained with 1.0-mm slice thickness. The data was transferred to the computer software AcquariusNET. Then the contours of the tibiofibular syndesmosis joint space were outlined on each axial CT slice and the collection of these slices were stacked using the computer software AutoCAD 2005, according to the spatial arrangement and geometrical coordinates between each slice, to produce a three-dimensional reconstruction of the joint space. The area of each slice and the volume of the entire tibiofibular joint space were calculated. The tibiofibular joint space at the 10th-mm slice level was also measured on axial CT scan images at normal, 1, 2 and 3-mm joint space diastases. RESULTS: The three-dimensional volume-rendering of the tibiofibular syndesmosis joint space from the spiral CT data demonstrated the shape of the joint space and has been found to be a sensitive method for calculating joint space volume. We found that, from normal to 1 mm, a 1-mm diastasis increases approximately 43% of the joint space volume, while from 1 to 3 mm, there is about a 20% increase for each 1-mm increase. CONCLUSIONS: Volume calculation using this method can be performed in cases of syndesmotic instability after ankle injuries and for preoperative and postoperative evaluation of the integrity of the tibiofibular syndesmosis.

Adult↗

PubMed2005

Role of mechanical factors in the evaluation of pedicle screw type spinal fixation devices.

Prior to implantation, spinal implants are subjected to rigorous testing to ensure safety and efficacy. A full battery of tests for the devices may include many steps ranging from biocompatibility tests to in vivo animal studies. This paper describes some of the essential tests from a mechanical engineering perspective (e.g., motion, load sharing, bench type tests, and finite element model analyses). These protocols reflect the research experience of the past decade or so.

Animals↗

PubMed2002

Identification of the anterior and posterior portions of the lateral pedicle cortex by roentgenograms in pedicle screw fixation.

Forty lumbar pedicles and pedicle screws in four cadavers were used to identify the anterior and posterior portions of the lumbar pedicle cortex by roentgenograms in order to evaluate the penetration of the pedicle cortex by pedicle screws intraoperatively. Firstly, the transverse pedicle angles were measured on roentgenograms. Three roentgenograms were taken on each pedicle in three different directions: (1). medial to the pedicle axis; (2). pedicle axis; (3). lateral to the pedicle axis. They revealed that the anterior portion of the lateral pedicle cortex was demonstrated by the pedicle lateral outline on the roentgenogram medial to the pedicle axis, and the posterior portion by the pedicle lateral outline on the roentgenogram lateral to the pedicle axis. Wire markers were used to confirm these data. Finally, anterior and/or posterior penetrations on the lateral pedicle cortex in pedicle screw fixation were studied by roentgenograms in these cadavers and showed that anterior penetration of lateral cortex was demonstrated by the view medial to the pedicle axis, and posterior penetration by the view lateral to the pedicle axis. It is concluded that projections medical and lateral to the pedicle axis are necessary to identify lateral screw penetration intraoperatively when X-ray checking is used.

Aged↗

PubMed2001

The location of the pedicle and pars interarticularis in the axis.

STUDY DESIGN: This is an anatomic and radiologic study on the lateral mass of the C2 vertebra. OBJECTIVES: To define the location of the pedicle and pars interarticularis in the C2 vertebra. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation of the C2 has been addressed in the literature. However, the use of the anatomic terminology of the pedicle or pars interarticularis (isthmus) in C2 is confusing in most of orthopaedic and neurosurgical literature since C2 is considered a transitional vertebra. METHODS: Twenty dry C2 vertebrae were obtained for observation of the external anatomy of the C2 from superior, lateral, and inferior views. Six C2 vertebrae were harvested from cadavers and sectioned in the sagittal, horizontal, and coronal planes to observe the internal structures of the lateral mass using high resolution radiographs. RESULTS: Based on observation, the pedicle of the C2 vertebra is defined as the portion beneath the superior facet and anteromedial to the transverse foramen. The pars interarticularis or isthmus is defined as the narrower portion between the superior and inferior facets. No remarkable difference in bone density and trabecular bone orientation between the pedicle and pars interarticularis was noted. CONCLUSIONS: It is still more appropriate to call this procedure "transpedicular screw fixation" in the C2 to avoid confusion, although this technique requires placing a screw from the posterior aspect of the inferior articular process through the isthmus and pedicle into the vertebral body.

Aged↗

PubMed2001

Computed tomography findings in patients with sacroiliac pain.

This retrospective study evaluated the diagnostic value of computed tomography in patients with sacroiliac pain. Computed tomography scans of the sacroiliac joints of 62 patients with sacroiliac joint pain were reviewed. The criteria to include the patient in the current study were pain relief after a local injection in the sacroiliac joint under computed tomography guidance, a physical examination consistent with a sacroiliac origin of the pain, and negative magnetic resonance imaging of the lumbar spine. A control group consisted of 50 patients of matched age who had computed tomography scans of the pelvis for a reason other than pelvic or back pain. Computed tomography scans showed one or more findings in 57.5% and 31% of the sacroiliac joints in the symptomatic and the control groups, respectively. The computed tomography scans were negative in 37 (42.5%) symptomatic sacroiliac joints with a positive sacroiliac joint injection test. The sensitivity of computed tomography was 57.5 % and its specificity was 69%. The finding of the current study suggests limited diagnostic value of computed tomography in sacroiliac joint disease because of its low sensitivity and specificity. With clinical suspicion of a sacroiliac origin of pain, intraarticular injection is currently the only means to confirm that diagnosis.

Adolescent↗

PubMed2001

Intramedullary fibular graft for tibiotalocalcaneal arthrodesis.

The intramedullary fibular graft was used in four patients for tibiotalocalcaneal fusion. There were three men and one woman. The average age was 49.7 years (range, 35-73 years). The initial injuries were three pilon fractures and one ankle fracture. Tibiotalocalneal arthrodesis was performed as a salvage procedure for patients with significant posttraumatic arthritis of the ankle, concomitant subtalar arthritis, and severe osteopenia. The average followup was 28 months (range, 24-31 months). All the patients had successful arthrodesis and were satisfied with the outcome results. The average preoperative American Orthopaedic Foot And Ankle Society ankle-hindfoot score for the whole group was 49.5 (range, 44-54) and improved postoperatively to 78.5 (range, 71-81). Three patients had a good score and one patient had a fair score. There was no postoperative infection or fracture of the graft.

Adult↗

PubMed2001

Anatomic considerations of the posterolateral lumbar disk region.

Sixteen embalmed cadavers were dissected to determine the location of the lumbar nerve root and sympathetic trunk with reference to the superior border of transverse process. In the posterolateral lumbar disk region, a safe zone was found between the anterior limit of the lumbar nerve and the posterior limit of the sympathetic trunk. It has a transverse dimension of 22 mm at the T12-L1 disk region and 25 mm at the L4-L5 disk region. The only exception to this was the genitofemoral nerve running close to the lateral margin of the L2-L3 disk. The study provides an understanding of the posterolateral orientation of the lumbar nerves and sympathetic trunk.

Aged↗

PubMed2001

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.

Aged↗

PubMed2001

Tosic external fixator in the management of proximal tibial fractures in adults.

This retrospective clinical study assessed proximal tibial fractures managed with the Tosic external fixator. Nineteen patients with 21 proximal tibial fractures treated with the Tosic external fixator between July 1997 and October 1998 comprised the study population. Eleven fractures were graded as 41A2, 3 fractures as 41 A3, 4 fractures as 41C1, and 3 fractures as 41 C2. Fourteen fractures were closed, and 7 fractures were open. Average time to healing was 1 7 weeks. No revision of fixation was needed. There were five cases of pin tract infection. Average range of knee motion was 2 degrees-135 degrees. These results indicate the Tosic external fixator is an efficient and simple way to treat proximal tibial metaphyseal fractures.

Adult↗

PubMed2001

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.

Aged↗

PubMed2001

Axial computed tomography of the pedicle in the lower cervical spine.

Using axial computed tomography (CT), we measured pedicle width, pedicle axis length, pedicle transverse angle, and distance between screw entry point and vertebrae midline in the cervical spines (C3-C7) of 40 patients. All measurements were greater in men than in women, and we noted significant sex differences at most levels of pedicle inner and outer widths (P < or = .05 or P < or = .01). Mean pedicle inner and outer widths for all levels and all patients ranged from 2.3 to 3.0 mm and from 5.0 to 6.0 mm, respectively. Mean distances between screw entry point and vertebrae midline ranged from 22.2 to 23.7 mm. Results of this study-along with axial CT measurements of individual pedicle diameter, pedicle transverse angle, and screw entry point-would be useful when considering and performing transpedicular screw fixation in the cervical spine.

Adult↗

PubMed2001

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.

Adult↗

PubMed2000

Computed tomographic findings in patients with persistent sacroiliac pain after posterior iliac graft harvesting.

STUDY DESIGN: A retrospective study of 24 sacroiliac joint computed tomographic (CT) scans of patients with persistent donor site pain. OBJECTIVE: To illustrate the computed tomographic findings of sacroiliac joints in patients who underwent posterior iliac bone graft harvesting with subsequent persistent donor site pain. SUMMARY OF BACKGROUND DATA: In a previous study the posterior iliac bone harvesting site was divided into three zones. Zone 1 carried no risk of violation of the synovial part of the sacroiliac joint. In Zones 2 and 3 there was a potential risk of violation to the synovial part of the sacroiliac joint. There is no study in the literature on the effect of violating the different parts of the sacroiliac joint during posterior iliac bone graft harvesting. METHODS: Computed tomographic scans of the sacroiliac joints of 22 patients with persistent pain in 24 sacroiliac joints after posterior iliac bone graft harvesting were retrospectively reviewed. RESULTS: Of the 16 sacroiliac joints with evidence of disruption of the inner table at the ligamentous part, 10 showed mild degenerative changes, and 6 showed moderate changes. Three joints with evidence of disruption of the inner table at the synovial part showed severe degenerative changes. Five joints with no evidence of inner table disruption did not show degenerative changes. CONCLUSION: There is a high prevalence of inner table disruption in patients with persistent sacroiliac joint pain after posterior iliac bone graft harvesting. The computed tomographic scan showed that involvement of the synovial part caused more severe degenerative changes than involvement of the ligamentous part.

Adult↗

PubMed2000

Vulnerability of the sympathetic trunk during the anterior approach to the lower cervical spine.

STUDY DESIGN: Anatomic dissection and measurements of the cervical sympathetic trunk relative to the medial border of the longus colli muscle and lateral angulation of the sympathetic trunk relative to the midline on both sides were performed. OBJECTIVE: To determine the course and location of the sympathetic trunk quantitatively and relate this to the vulnerability of the sympathetic trunk during the anterior approach to the lower cervical spine. SUMMARY OF BACKGROUND DATA: The sympathetic trunk is sometimes damaged during the anterior approach to lower cervical spine, resulting in Horner's syndrome with its associated ptosis, meiosis, and anhydrosis. No quantitative regional anatomy describing the course and location of the sympathetic trunk and its relation to the longus colli muscle is available in the literature. METHODS: In this study, 28 adult cadavers were used for dissection and measurements of the sympathetic trunk. The distance between the sympathetic trunk and the medial borders of the longus colli muscle at C6 and the angle of the sympathetic trunk with respect to the midline were determined bilaterally. The distance between the medial borders of the longus colli muscle from C3 to C6 and the angle between the medial borders of the longus colli muscle also were measured. RESULTS: The sympathetic trunk runs in a superior and lateral direction, with an average angle of 10.4 +/- 3.8 degrees relative to the midline. The average distance between the sympathetic trunk and the medial border of the longus colli muscle is 10.6 +/- 2.6 mm. The average diameter of the sympathetic trunk at C6 is 2.7 +/- 0.6 mm. The length and width of the middle cervical ganglion were 9.7 +/- 2.1 mm and 5.2 +/- 1.3 mm, respectively. The distance between the medial borders of the longus colli muscle was 7.9 +/- 2.2 mm at C3, 10.1 +/- 3.1 mm at C4, 12.3 +/- 3.1 mm at C5, and 13.8 +/- 2.2 mm at C6, and the angle between the medial borders of the longus colli muscle was 12.5 +/- 4. 7 degrees. CONCLUSIONS: The sympathetic trunk may be more vulnerable to damage during anterior lower cervical spine procedures because it is situated closer to the medial border of the the longus colli muscle at C6 than at C3. The longus colli muscles diverge laterally, whereas the sympathetic trunks converge medially at C6. As the transverse foramen or uncovertebral joint is exposed with dissection or transverse severance of the longus colli muscle at the lower cervical levels, the sympathetic trunk should be identified and protected.

Aged↗

PubMed2000

The optimal transarticular c1-2 screw length and the location of the hypoglossal nerve.

BACKGROUND: Injury to the hypoglossal nerve is a complication associated with transarticular C1-2 screw placement. This complication can be caused by a misdirected or too long screw. Little is known about the optimal screw length and its relationship to the hypoglossal nerve. METHODS: Twenty cervical spine specimens were used to study the optimal length of the transarticular C1-2 screw. Using the Magerl technique, a 3.0 mm drill bit was inserted into the C2 lateral mass, passing through the C1-2 facet joint and penetrating the upper portion of the ventral cortex of the lateral mass of the atlas. After drilling, the hole length was measured between the dorsal cortex of the C2 inferior articular process and the ventral cortex of the C1 lateral mass. In addition, six sagittal-sectioned cadavers were carefully dissected to observe the location of the hypoglossal nerve in the anterior aspect of the atlantoaxial region. RESULTS: The results of the measurements showed that the mean optimal screw path length for all specimens was 38.1 +/- 2.2 mm with a range of 34-43 mm. There was no significant difference between sexes in the screw path length (p 0.05). The hypoglossal nerve lies vertically in front of the lateral portion of the C1 lateral mass and the C1-2 facet joint. The area where the hypoglossal nerve lies is approximately 2-3 mm lateral to the middle of the anterior aspect of the C1 lateral mass. CONCLUSIONS: This study suggests that the mean optimal transarticular C1-2 screw length may be 38 mm; however, the determination of the accurate optimal C1-2 screw length should be made on an individual basis. Risk to the hypoglossal nerve can be eliminated if Magerl's technique is performed exactly.

Aged↗

PubMed2000

Anatomic considerations of costotransverse screw placement in the thoracic spine.

BACKGROUND: Numerous techniques have been reported to restore spinal stability and to correct spinal deformities, including rods with wires/hooks, and rods or plates with pedicular screws. It was thought that posterior fixation of the thoracic spine through the costotransverse joint may be another alternative. METHODS: Nine cadavers were obtained for study of screw fixation of the costotransverse joint for posterior thoracic instrumentation. The entrance point for screw insertion was designed to be at the posterior center of the clubbed extremity of the transverse process. From this point, a 3-mm drill bit was used to create the screw path penetrating the costotransverse joint and the ventral cortex of the rib. Under direct visualization of the costotransverse joint, the drill bit was directed parallel to the sagittal plane and toward the upper portion of the rib. Measurements included the screw path length and sagittal angulation. Also, the distance between the superior borders of the transverse process and the tubercle of the rib and the anatomic relationship of the drill bit exit to the intercostal vessels and nerves were evaluated. RESULTS: The maximum length of the screw path was found at T1 (19.7 mm), whereas the minimum length was noted at T4-T5 (13.9 mm). This value decreased gradually from T1 to T4-T5, and slightly increased to T10. The larger sagittal angles of the screw path were found at the levels of T1-T4 (78-86 degrees ), whereas the smaller were noted at the levels below T5 (53-61 degrees ). The mean distance between the superior borders of the transverse process and the tubercle of the rib was smaller at T1-T5 (0.2-0.4 mm), and significantly increased to T8 (5. 1 mm), and then slightly decreased to T10. The variation of this parameter was remarkable. All of the exit points for the drill bit were located in the upper half of the rib, and away from the intercostal vessels. CONCLUSIONS: The ideal screw orientation is parallel to the sagittal plane, and angled 80-90 degrees relative to the frontal plane for T1-T4 and 50-70 degrees for T5-T10 superiorly, starting at the posterior center of the transverse process. Costotransverse screw fixation in the thoracic spine may be an alternative to pre-existing methods.

Aged↗

PubMed2000

The anatomy of the posterior interosseous nerve as a graft.

Thirty upper limbs from skeletally mature embalmed cadavers were studied to determine the anatomic reliability of the posterior interosseous nerve as a donor nerve graft. The posterior interosseous nerve branches 0.43 +/- 0.52 cm from the distal edge of the superficial head of the supinator and 8 +/- 1.6 cm from the lateral epicondyle form a common leash. There are 6 branches, which are arranged from the ulnar to the radial side at their origin from this leash. The first and second branches supply the extensor digitorum communis, the third branch supplies the extensor carpi ulnaris, the fourth branch supplies the extensor digiti minimi, and the fifth branch arises from the undersurface of the common leash and divides into 2 sub-branches (medial and lateral) 10.1 +/- 3.2 cm distal to the lateral epicondyle and 12.8 +/- 2.2 cm proximal to Lister's tubercle. These 2 sub-branches make an inverted V shape around the extensor pollicis longus. The medial branch supplies the extensor pollicis longus and extensor indicis proprius. The lateral branch supplies the extensor pollicis longus and extensor pollicis brevis and ends at the wrist capsule. At a mean distance of 8.1 +/- 1.2 cm proximal to Lister's tubercle the lateral sub-branch gives off its last muscular branch to the extensor pollicis longus and becomes a pure sensory terminus. As the terminal part of the lateral sub-branch approaches the wrist capsule it expands at a mean distance of 1.9 +/- 0.5 cm proximal to Lister's tubercle. The sixth branch arises from the radial side of the common leash and divides into 3 sub-branches. The first sub-branch supplies the abductor pollicis longus and extensor pollicis brevis, the second supplies the abductor pollicis longus, and the third supplies the superficial head of the supinator. This study showed that the mean length obtainable for harvesting the lateral sub-branch of the fifth branch of the posterior interosseous nerve is 6.2 +/- 0.7 cm, which represents the length of the nerve between the last muscular branch to the extensor pollicis longus to the point at which the nerve expands.

Adult↗

PubMed2000

Cervical intervertebral disc space narrowing and size of intervertebral foramina.

Computer-assisted simulation of C4-C5, C5-C6, and C6-C7 intervertebral disc space narrowing was performed on 16 anatomic specimen cervical spines to determine the relationship of the cross sectional foraminal areas with the degree of narrowing of the cervical intervertebral disc space. Compared with normal foraminal area values, reduction of 20% to 30% of the foraminal area was found after 1 mm narrowing of the intervertebral disc spaces; reduction of 30% to 40% of the foraminal area was found after 2 mm narrowing of the intervertebral disc space; and reduction of 35% to 45% of the foraminal area was found after 3 mm narrowing of the intervertebral disc space. Statistically significant differences were found among the remaining cross sectional foraminal areas after different degrees of intervertebral disc space narrowing. Compression of the nerve root within the intervertebral foramina after the collapse of the intervertebral disc space cannot be ignored, and an appropriate surgical procedure to maintain the normal height of the disc space is essential. The size of the intervertebral foramen is related directly to the height of the intervertebral disc space. A 3-mm vertical reduction of the intervertebral disc space is associated more frequently with severe narrowing of the neuroforamen.

Aged↗