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Lower limb morphology and risk of overuse injury among male infantry trainees.

The effect of anatomic variation on the risk of overuse injuries has not been adequately evaluated. To determine the association of several common anatomic characteristics (genu varum, genu valgum, genu recurvatum, and lower limb length differences) with risk of overuse injury, we made prospective morphologic measurements of young men prior to beginning 12 week of Army infantry training. The training included frequent running, marching, calisthenics, and other vigorous activities. Lower extremity anatomic landmarks were high-lighted, and front- and side-view photographic slides were taken of the 294 study volunteers. The slides were compute digitized, and the following measures calculated: pelvic width to knee width ratio (to assess genu valgum/varum), quadriceps angle (Q-angle), knee angle at full extension, and lower limb length differences. The cumulative incidence of lower limb overuse injury was 30%. Relative risk of (RR) of overuse injury was significantly higher among participants with the most valgus knees (RR = 1.9). Those with Q-angle of more than 15 degrees had significantly increased risk specifically for stress fractures (RR = 5.4). Anatomic characteristics were associated with several other types of injuries, including pain and nonacute muscle strain due to overuse. This pilot study provides evidence that some lower limb morphologic characteristics may place individuals at increased risk of overuse injuries.

Chi-Square Distribution↗

Single imaging modality evaluation of living donors in liver transplantation: magnetic resonance imaging.

BACKGROUND: Liver graft size, anatomy of the bile duct and the vascular inflow and outflow are essential for living related liver transplantation (LRLT). Preoperative delineation of those variations that would change the operative procedure to achieve a successful result especially in an emergency condition. PURPOSE: Our aim was to develop a rapid and noninvasive imaging diagnostic method for the detection of anatomical variants that is mandatory for a safe operation when selecting potential liver transplant living donors. We used a different magnetic resonance (MR) imaging technique, which enabled to us to exploit the anatomical landmark of the liver, signal enhancement of blood flow in the abdomen, and the intrahepatic biliary routes inside the liver. Then, with the help of Advantage Window workstation reconstruction, the reconstructed single vascular or biliary systems were displaced in a three-dimensional fashion and the whole examination finished within 30 min. METHODS: Modification of the standard MR technique was performed on a superconductive 1.5T whole body image scanner, MR arteriogaphy, venography, and cholangiography with three-dimensional reconstruction in evaluating the anatomy of the hepatic arteries, hepatic veins, portal venous system, bile ducts, and liver size in potential liver transplant living donors. These anatomical structures were compared with traditional imaging methods. RESULTS: In all 38 cases, as well as delineation of the portal vein detail to the segmental level was satisfactorily obtained in this MR study. The images were well displayed in a three-dimensional fashion, which had good correlation with images from traditional imaging modalities and operative findings. In 86.8% cases, the MR arteriography was well matched with the celiac angiography. Of those 17 operative cases, estimation of liver volume was well correlated with the liver graft within 3.9-12.5% variation. In the major hepatic vein, we obtained 100% accuracy and 88.2% in the minor branches. Of 12 donors received intraoperative cholangiography during liver donation, good correlation of biliary anatomy was achieved. One donor was excluded from graft donation due to the complicated arterial supply to the left liver. According to the anatomical variation, surgical procedures in graft harvesting and anastomosis were readjusted and no major complications were found in those donors and all recipients survived after liver transplantation. CONCLUSION: MR volumetry, venography, angiography, and cholangiography with three-dimensional reconstruction is sufficient for all major imaging evaluation. It may replace the traditional conventional catheter angiography, computed tomography, sonography and endoscopic retrograde cholangiography as a single investigation in the evaluation of the potential liver transplant donors. Angiography is only valuable in suboptimal cases and intraoperative cholangiography is only performed in biliary ductile variants.

Adult↗

Cervical spine geometry in the automotive seated posture: variations with age, stature, and gender.

In the mid 1970s, UMTRI investigated the biomechanical properties of the head and neck using 180 "normal" adult subjects selected to fill eighteen subject groups based on age (young, mid-aged, older), gender, and stature (short, medium, and tall by gender). Lateral-view radiographs of the subjects' cervical spines and heads were taken with the subjects seated in a simulated automotive neutral posture, as well as with their necks in full-voluntary flexion and full-voluntary extension. Although the cervical spine and lower head geometry were previously measured manually and documented, new technologies have enabled computer digitization of the scanned x-ray images and a more comprehensive and detailed analysis of the variation in cervical spine and lower head geometry with subject age, stature, and gender. After scanning the radiographic images, 108 skeletal landmarks on the cervical vertebrae and 10 head landmarks were digitized. The resulting database of cervical spine and head geometry was used to study cervical spine curvature, vertebral dimensions, and head/neck orientation as functions of age, gender, and stature. The data were used to characterize neutral posture cervical spine curvatures using two methods: a curvature index and Bézier spline functions. Lateral-view vertebral dimensions were also calculated for each subject, and a cascading series of equations was developed to estimate vertebral size and shape for a selected age, stature, and gender. The orientation of the cervical spine was defined using a neck chord angle, where the neck chord was varied to use different anatomical landmarks and estimates of joint centers for the top and bottom of the neck chord. Results from the study have been incorporated into a MS-Access based software package that allows researchers and modelers to generate cervical spine geometries for occupants of a specified age, gender, and stature. The program allows selection of individual occupants from the database that meet age, stature, gender, or curvature criteria, or creation of a composite cervical spine geometry representative of the selected age, gender, and stature. This tool will allow researchers to configure and vary cervical spine geometry in computer models and experimental test setups used to study head and neck impact response and injury risk.

Journal Article↗

Differential cortical thickness across the central sulcus: a method for identifying the central sulcus in the presence of mass effect and vasogenic edema.

BACKGROUND AND PURPOSE: Identification of the motor strip on MR imaging studies is difficult in the presence of mass effect and vasogenic edema because sulcal landmarks are obscured. We hypothesize that a difference in cortical thickness between the motor and sensory strips is readily apparent on T2-weighted images in the presence of vasogenic edema and reliably identifies the central sulcus. METHODS: Thirteen patients with brain tumors resulting in vasogenic edema near the central sulcus were identified. The cortical thickness of the anterior and posterior banks of the central sulcus as well as the neighboring sulci in the frontal and parietal lobes were measured from T2-weighted images. Similar measures were obtained from neighboring sulci in the frontal and parietal lobes. Location of the central sulcus was confirmed with standard anatomic landmarks in all patients and by intraoperative cortical mapping in 2 patients. RESULTS: A twofold difference in cortical thickness between the anterior and posterior banks of the central sulcus uniquely identified the central sulcus on T2-weighted images in the presence of vasogenic edema, despite the marked distortion of sulcal anatomy as a result of mass effect. This relationship was not present in neighboring sulci. CONCLUSION: Cytoarchitectonic differences in the motor and sensory cortices result in a markedly thicker posterior than anterior bank of the central sulcus that is readily visible on routine T2-weighted images in the presence of vasogenic edema. Therefore, the cortical thickness can serve as a complementary method in identification of the motor strip in patients with mass effect.

Brain Edema↗

Frameless stereotaxy and anterior cervical surgery.

OBJECTIVE: The role of a frameless image guidance system for anterior cervical surgery was evaluated in 40 patients with cervical spondylosis. An assessment was made of the challenges posed in achieving accurate three-dimensional image registration in the absence of multiple fixed anatomical landmarks, and a solution to this problem is outlined using a novel registration tracking device. MATERIALS AND METHODS: Patients underwent preoperative CT scanning of the surgical field of interest, and the image data was reconstructed on a StealthStation (Sofamor Danek, Memphis, Tennessee, USA). An image guidance tracking device was attached to a modified Caspar retractor. Point matching and surface mapping were used for registration. RESULTS: It was not possible to achieve accurate registration in the first 7 patients. In the next 5 patients, the time taken to achieve registration was prolonged. For 28 patients, registration was achieved in an acceptable time with an accuracy of 0.74 +/- 0.4 mm. Anatomical resection margins were accurately identified and 36 anterior cervical screws were precisely placed. CONCLUSIONS: Frameless stereotaxy can now be applied to procedures involving the anterior cervical spine. Potential benefits include accurate definition of the anatomy, demonstration of resection margins, and intraoperative guidance. The technique may prove particularly useful in cases of complex or disrupted anatomy.

Adult↗

Scapular thickness--implications for fracture fixation.

The purpose of this study was to measure and map scapula osseous thickness to identify the optimal areas for internal fixation. Eighteen (9 pairs) scapulae from 2 female and 7 male cadavers were used. After harvest and removal of all soft tissues, standardized measurement lines were made based on anatomic landmarks. For consistency among scapulae, measurements were taken at standard percentage intervals along each line approximating the distance between two consecutive reconstruction plate screw holes. Two-mm-diameter drill holes were made at each point, and a standard depth gauge was used to measure thickness. The glenoid fossa (25 mm) displayed the greatest mean osseous thickness, followed by the lateral scapular border (9.7 mm), the scapula spine (8.3 mm), and the central portion of the body of the scapula (3.0 mm). To optimize screw purchase and internal fixation strength, the lateral border, the lateral aspect of the base of the scapula spine, and the scapula spine itself should be used for anatomic sites of internal fixation of scapula fractures.

Aged↗

[Virtual MR endoscopy of the ventricles prior to neurosurgical interventional endoscopy -- evaluation of different presentation techniques].

PURPOSE: In the past, virtual endoscopies have been performed for planning of endoscopic interventions or for diagnostic purposes in various organ systems with increasing frequency. This study evaluates the ability of virtual ventricular endoscopy to depict anatomical structures and the use for planning of real endoscopy. MATERIALS AND METHODS: In a prospective study, 4 volunteers and 8 patients were examined with MRI. In 3 of the patients endoscopy was performed by our neurosurgeons thereafter. The calculation of the virtual endoscopy was based on 1 mm sagittal T2-weighted images. Comparison of surface rendering and volume rendering was made by means of video sequencing of individual views, and these were compared with the intraoperative endoscopic videos concerning the depictability of anatomical landmarks. RESULTS: The reconstructions using volume rendering were more significant and easier to calculate than those based on surface rendering. Virtual endoscopy in the transparent mode allowed visualization of hazardous structures outside the ventricular system such as the basilar artery tip. Transparent 3D images of the ventricles gave a good overview on the depicted structures and enabled a better orientation during the virtual camera flight than surface rendered views. CONCLUSION: MR-based virtual endoscopy of the ventricular system can be obtained on the basis of surface- and volume-rendered views of sagittal T2-weighted thin sections. Preoperative utilization of this method simplifies the planning of endoscopy by visualization of anatomical structures.

Brain Diseases↗

Adipose compartments of the upper eyelid: anatomy applied to blepharoplasty.

Many authors have indicated the presence of ectopic or accessory upper eyelid fat pads, but the effective rate of eyelid fat variations and the corresponding clinical features are still unclear. The purpose of this study was to evaluate the variability of upper lid fat and to define the anatomical landmarks of the adipose pockets of the upper lid. From January of 1998 to January of 2002, the authors investigated the upper eyelid fat compartments of 47 patients who underwent upper blepharoplasty. To support surgical findings, 11 fresh cadavers were also investigated; the anatomy of the intraorbital fat and of the upper eyelid fat compartments was reviewed. Ten patients (21.3 percent) showed an accessory fat pad in the upper lid, which was found on both sides in nine cases. In all patients, the third fat pad was situated lateral to the two classic compartments described by Castanares, behind the orbital septum. Surgical dissections demonstrated that this fat pad derived from the preaponeurotic fat. Anatomical dissections in three cadavers demonstrated an accessory fat compartment protruding under the inferior border of the lacrimal gland. This protruding fat derived from the preaponeurotic fat in all cases and might justify the clinical appearance of a bulge or fullness in the lateral third of the upper eyelid. In the authors' experience, the presence of an accessory upper eyelid fat pad was a frequent finding during blepharoplasty; it could be found and actually resected in about 21 percent of all cases. Surgical and experimental findings put this element as a lateral physiological extension of the preaponeurotic fat that can anteriorly protrude under the inferior border of the lacrimal gland toward the orbital septum. The clinical appearance may be a bulge or fullness in the upper eyelid, and its resection can better define the lateral one third of the supratarsal fold.

Adipose Tissue↗

[Functional localization of the somatomotor area by magnetoencephalography].

Precise localization of the current dipole by the magnetoencephalography (MEG) has enabled us to combine the functional information onto the anatomical landmarks. This merit can be best exhibited when the dipole is situated in the superficial cortex and directed parallel to the skull surface. However, before utilizing MEG extensively as a clinical tool, it is inevitable to confirm the precision of the source localization by comparing the estimation with the actual sources. Somatosensory evoked field (SEF) following the electric shock to the peripheral nerve and movement-related cortical field (MRCF) associated with self-paced movement can show us the estimated sources at the postcentral and precentral cortex, respectively, with somatotopic organization. These localizations were confirmed by the direct recordings from the human brain surface during the operation, even if the corresponding areas were anatomically distorted by some lesion occupying the central area. In addition, MEG can localize second somatosensory area (SII) over the superior bank of the Sylvian fissure as well as posterior parietal cortex (PPC), which are difficult to be detected by the EEG recording. These reliable estimation enables us to apply MEG to clarification of pathogenesis of various diseases and source localization for higher brain function.

Evoked Potentials, Somatosensory↗

Computer-aided placement of deep brain stimulators: from planning to intraoperative guidance.

In current practice, optimal placement of deep-brain stimulators (DBSs) used to treat movement disorders in patients with Parkinson's disease and essential tremor is an iterative procedure. A target is chosen preoperatively based on anatomical landmarks identified on magnetic resonance images. This point is used as an initial position that is refined intraoperatively using both microelectrode recordings and macrostimulation. In this paper, we report on our current progress toward developing a system for the computer-assisted preoperative selection of target points and for the intraoperative adjustment of these points. The system consists of a deformable atlas of optimal target points that can be used to select automatically the preoperative target, of an electrophysiological atlas, and of an intraoperative interface. Results we have obtained show that automatic prediction of target points is an achievable goal. Our results also indicate that electrophysiological information could be used to resolve structures not visible in anatomic images, thus improving both preoperative and intraoperative guidance. Our intraoperative system has reached the stage of a working prototype and we compare targeting accuracy as well as the number of paths needed to reach the targets with our system and with the method in current clinical use.

Algorithms↗

Imaging-based nodal classification for evaluation of neck metastatic adenopathy.

OBJECTIVE: This study was undertaken to create an imaging-based classification for the lymph nodes of the neck that will be readily accepted by clinicians, result in consistent nodal classification, and be easily used by radiologists. SUBJECTS AND METHODS: Over an 18-month period, the necks of 50 patients with cervical lymphadenopathy were scanned with CT, MR imaging, or both. Imaging anatomic landmarks were sought that would create a nodal classification of these necks similar to the clinically based nodal classifications of the American Joint Committee on Cancer and the American Academy of Otolaryngology-Head and Neck Surgery. Each nodal level was defined to ensure consistent nodal classification and eliminate areas of confusion existing in the clinically based classifications. RESULTS: Necks were classified using the imaging-based classification and then compared with the classification of the same necks using the most common clinically based classifications. The imaging-based nodal classifications of the superficial nodes were the same as the clinically based classifications; however, the deep nodes of eight patients were found only by imaging. The anatomic precision and the level definition afforded by sectional imaging allowed the radiologists to use the imaging-based classification in a consistent manner. CONCLUSION: This imaging-based classification has been endorsed by clinicians who specialize in head and neck cancer. The boundaries of the nodal levels were easily discerned by radiologists and yielded consistent nodal classifications. The reproducibility of this classification will allow it to become an essential component of future classifications of metastatic neck disease.

Adult↗

Endoscopic dacryocystorhinostomy: anatomical approach.

Dacryocystorhinostomy is the surgical treatment for nasolacrimal blockage. In recent years, the endoscopic approach has become more popular due to the development of nasal endoscopes and the ease of surgery in comparison to the external approach. In order to identify the lacrimal duct during surgery, surgeons insert a light pipe into the lacrimal duct and then drill or chisel the hard bone of the frontal process of the maxilla to remove the bony covering of the sac and duct. It is obvious that knowledge of the anatomy of the lacrimal sac/duct within the nose is essential for the surgeon. The lacrimal apparatus in the nose was studied using 10 cadaveric half-heads (5 males and 5 females) to establish the anatomical landmarks and most accessible part of the lacrimal duct from within the nose. Although there was solid bone covering the whole length of the sac and the duct, the posteromedial aspect of the lower sac and upper duct was covered by the ultra thin lacrimal bone (average thickness 0.057 mm) which was consistently found to be lying immediately anterior to the uncinate process in the middle meatus, thus constituting a "surgical window" (average size 2.5 mm x 7.2 mm) whereby surgical entry into the lacrimal duct becomes relatively easy. The lower part of the lacrimal sac and the upper part of the lacrimal duct can therefore be easily accessed from within the nose by following this anatomical approach, thus avoiding the need to drill or chisel the dense frontal process of the maxilla.

Aged↗

Ultrasound assessment of the female perineum: technique, methods, indications and ultrasound anatomy.

PURPOSE: To present and promote the use of ultrasound in the evaluation of perineal disorders. MATERIALS AND METHODS: The technique and methodology for a correct ultrasound examination of the perineum, starting from the preparation of patient and equipment, are reported in detail. Ultrasound accesses to the perineum are the following: perineal or vulvar; introital; vaginal; transrectal. The transducers used also vary in technical features and morphology. There is no general agreement as to which access and transducer should be used in the ultrasound assessment of the perineum. We believe that each type of access and transducer has advantages and disadvantages over the others and that the opposition among supporters of different accesses and transducers should be overcome. The various systems should be considered complementary with one another and can all be used to reach a better ultrasound diagnosis. ULTRASOUND ANATOMY OF THE PERINEUM: A detailed description of the possible indications and of the ultrasound anatomy of the pelvic floor in relation to the type of transducer and access that can be used is reported. It is suggested that each ultrasound examination of the perineum should be performed following fast abdominal ultrasound evaluation. Perineal scans should be obtained during all functional phases: at rest, during abdominal straining and contraction. When a perineal access is used, it is always advisable to visualize the pubis as it is an important anatomical landmark for dynamic biometric evaluations. We believe that urethral ultrasound, performed during the dynamic phases, is the most accurate method for evaluating cervico-urethral mobility and is thus extremely useful for a correct pre-operative analysis. An increase in normal urethral mobility is correlated with female urinary incontinence, particularly with stress incontinence. Further-more, ultrasound proves to be valuable in the evaluation of other disorders, such as urogenital prolapses, especially enterocele, and anal sphincter defects. In the latter case, when a specific rotating endoanal probe for anal sphincter dysfunctions is not available, perineal ultrasound may be a useful adjunct for correct evaluation if complemented by a sensible use of clinical data. CONCLUSIONS: As in other anatomical fields, ultrasound proves to be inexpensive, harmless and well tolerated by patients. The wealth of information provided by this method in the assessment of the main anatomic and functional alterations of the perineum makes the use of more invasive and expensive radiographic techniques unnecessary. Its correct use, following an adequate training period, significantly reduces the need for conventional radiography and MR contrast-enhanced examinations which should be regarded as second-line examination tools.

Female↗

Identification of the optimal orientation of oblique sections through multiple parallel CT images.

A method for identifying the optimal orientation of images of oblique sections computed from a "stack" of parallel computed tomography (CT) scans is presented. The identification of the optimal orientation is facilitated by the display of the stack of cross-sectional images (volume image) in three dimensions. Moreover, by displaying the section image as a brightened plane within the volume, imaged anatomic landmarks may be utilized to guide the process of identifying the desired image plane orientation. The volume image display method, termed projection imaging, involves the numerical projection of the volume picture elements (voxels) of the three-dimensional (3-D) reconstruction onto a plane to form a two-dimensional projection image. For X-ray CT, these projections are analagous to, and appear very much like, conventional radiographs. The volume image is seen in three dimensions by appropriately viewing stereo-pair projections of the volume formed from viewpoints that are 2 to 8 degrees apart. The display of the 3-D reconstruction as a volume image eliminates the need for the observer to mentally reconstruct the spatial relationships of the oblique section to anatomic features within the volume.

Animals↗

Anatomy of the coronoid process.

PURPOSE: Coronoid injuries are classified according to the size of the coronoid fracture. The purpose of this study was to provide a detailed anatomic description of the coronoid process, with specific focus on the coronoid height, the coronoid width, and the olecranon-coronoid angle. METHODS: Thirty-five cadaveric arms were dissected. All soft tissue was removed and the ulna was disarticulated from the humerus, radius, and the carpal bones. A 3-dimensional digitizing system was used to locate 19 anatomic landmarks on each specimen. By using the 3-dimensional coordinates of the landmarks, the coronoid heights, proximal ulnar widths, and olecranon-coronoid angles were determined. RESULTS: The coronoid height, with its base defined by the trough of the trochlear notch and the slope change of the distal coronoid process, measured 15 mm and was 42% of the ulnar height. The coronoid height, with its base defined by the transverse groove of the sigmoid notch at the guiding ridge and the distal insertion of the brachialis muscle, measured 15 mm and was 43% of the ulnar height. The olecranon-coronoid angle ranged between 33 degrees and 38 degrees . CONCLUSIONS: For lateral radiographic classification of coronoid fractures, coronoid height is best defined by the trough of the trochlear notch and the slope change of the distal coronoid process. For anatomic studies, coronoid height is best defined by the transverse groove of the sigmoid notch at the guiding ridge and the distal insertion of the brachialis muscle. The olecranon-coronoid angle is best defined by the angle formed by the lines from the olecranon tip through the coronoid tip and through the slope change of the distal coronoid process. The coronoid anatomy measurements reported in this study may help to improve coronoid fracture classification.

Aged↗

Cone beam computerized tomography-based dental imaging for implant planning and surgical guidance, Part 1: Single implant in the mandibular molar region.

Computerized tomography (CT)-based dental imaging for implant planning and surgical guidance carries both restorative information for implant positioning, as far as trajectory and distribution, and radiographic information, as far as depth and proximity to critical anatomic landmarks such as the mandibular canal, maxillary sinus, and adjacent teeth. This case report describes a systematic approach to the planning and surgical placement of a single implant-supported crown, utilizing CT-based dental imaging for implant planning and surgical guidance. The simple steps result in the accurate transfer of critical radiographic information to the surgical site.

Adult↗

A fluoroscopy-based surgical navigation system for high tibial osteotomy.

High tibial osteotomy is a widely accepted treatment for unicompartmental osteoarthritis of the knee and other lower extremity deformities, particularly in young and active patients. However, it is generally recognized as a technically demanding procedure. The lack of intraoperative control of the mechanical axis of the affected limb often results in postoperative malalignments, which is one of the main reasons for poor long-term results. Moreover, inaccurate osteotomies, such as insufficient or excessive bone cut, or incorrect orientation of the chisel or saw blade, have been observed. A computer assisted intraoperative planning and navigation system is therefore proposed in order to address these technical problems. During operation, fluoroscopic images are acquired and anatomical landmarks are digitized; a patient-specific coordinate system is established accordingly. After the three-dimensional measurement of the deformity and interactive planning of the osteotomy plane, the deformity is corrected under navigational guidance. The proposed system has been successfully introduced into the clinical practice of surgery after encouraging laboratory evaluations, with results affirming that it is safe and accurate.

Fluoroscopy↗

Computerized restoration of nonhomogeneous deformation of a fossil cranium based on bilateral symmetry.

We developed a computerized method of correcting plastic deformation of a fossil skull, based on bilateral symmetry with respect to the midsagittal plane, and applied this method to reconstruction of a fossilized Proconsul heseloni cranium (KNM-RU-7290A). A three-dimensional (3D) model of the fossil was generated using consecutive cross-sectional images retrieved from computed tomography. 3D coordinates of anatomical landmarks that should be located on the midsagittal plane and pairs of landmarks that should be symmetrical with respect to this plane were acquired. These landmarks were then repositioned so that geometrical constraints were satisfied, while translated distances of landmarks were minimized. We adopted a thin-plate spline function to mathematically describe the 3D nonlinear volumetric transformation between acquired and repositioned landmarks. Using this function, the entire fossil shape was transformed, and the effect of reversing the deformation could be visualized. The results indicated that the proposed method was effective in eliminating nonhomogeneous deformation of the fossil skull. The antemortem appearance of the skull cannot be completely restored by this method alone, due to methodological limitations. However, the presented method has a role as an adjunct in complementing conventional restoration techniques on account of its objective nature.

Animals↗