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Biomedical subjects

M A Pirela-Cruz

Publications and source records attributed to M A Pirela-Cruz.

9 recordsLinked to original sources
PubMed2003

Frequency and characteristics of the scaphoid cortical ring sign.

The scaphoid cortical ring sign (CRS) has been identified as a radiological indicator of ligamentous injury of the wrist. It has been associated with some pathokinematic states. There exists a range of wrist positions where the CRS may be normally present. The purpose of this study was to define the range of motion when the CRS can normally be observed on a standard posteroanterior radiograph and, in turn, to define the range where the CRS is not expected to be present. One hundred and nine posteroanterior radiographs of normal wrists were evaluated for the presence, partial presence and absence of the scaphoid CRS. The results were correlated with the radio-metacarpal (RM) angle in neutral palmar-dorsiflexion of the wrist. The range of wrist deviation for the wrists studied was -10.0 degrees (radial deviation) to 23.0 degrees (ulnar deviation). We defined the normal (and abnormal) range as being two standard deviations from the mean. The CRS was present in 25% of the radiographs evaluated. Moreover, the CRS was found to be present at 2.7 degrees (+/-7.7 degrees ) of radial deviation with a calculated range of -18.1 degrees to 12.7 degrees. The CRS was absent at 12.4 degrees (+/-11.7 degrees ) of ulnar deviation. It is concluded that the CRS observed at values less than 13 degrees of ulnar deviation may or may not be abnormal. If the CRS is observed at a RM angle of 13 degrees of ulnar deviation or greater, it should be considered pathological. The CRS, however, should be used in conjunction with other clinical findings of carpal instability.

Adolescent↗
PubMed1998

Kinematics of the capitolunate joint in the sagittal plane. A new method based on reference points and triangulation.

A new method of assessing capitolunate alignment is presented. Three anatomical carpal reference points were evaluated on lateral radiographs using triangulation. Connecting these three points forms a triangle with dorsal, palmar and somewhat vertical sides. One hundred normal lateral wrist radiographs were measured. The overall dorsal limb (DL) to palmar limb (PL) ratio was found to be 0.74 (SD 0.07) over a range of 40 degrees extension to 42 degrees flexion. As the DL to PL ratio approached 1.0, a dorsal intercalated segment instability (DISI) deformity developed. Conversely, as the DL to PL ratio approached 0.5, a palmar intercalated segment instability (PISI) occurred. This method appears useful for evaluating static lateral radiographs for intercalary carpal alignment and possibly instability.

Adolescent↗
PubMed1997

Kienböck's disease. I. Anatomy and Etiology.

Cumulative trauma disorders (CTD) pose a major industrial problem in terms of increased medical costs, lost productivity and degraded worker health and safety. From an anatomical view, CTD's are classified into three major categories: tendon disorders, neurovascular disorders and nerve disorders. Up until recently these categories seemed to cover CTD of the upper extremity, however, Kienböck's disease, a typically less common disease and one that does not fit into the established CTD categories, has been observed to exhibit CTD characteristics and does appear in the manufacturing environment. The most common types of employment observed to exhibit individuals with this disease are carpentry, jobs involving the use of pneumatic tools (wrench), spot welders, sheet metal work, farmers and factory workers. The present article makes a critical examination of the relevant anatomy and etiologic aspects of this disease.

Cumulative Trauma Disorders↗
PubMed1997

Kienböck's disease. II. Risk factors, diagnosis, and ergonomic interventions.

The term CTD has been used to refer to those musculoskeletal impairments that appear to be work-related and tend to be chronic. Upper extremity CTD are categorized in three major groups: tendon disorders, neurovascular disorders, and nerve. Kienböck's disease, on the other hand, has been documented in the workplace and has a similar etiology, but due to current anatomic classifications cannot be considered a CTD. With this in mind, the present article reviews risk factors, diagnosis, and treatment, with the purpose of providing physicians, engineers, and designers with information to reduce the risk of workers developing this potentially debilitating disease. Furthermore, additional support will be accumulated and combined with Part I of this article with the intent of introducing into the literature a new category of upper extremity CTD: Bone Disorders.

Ergonomics↗
PubMed1994

Vascularized bone grafts.

Free vascularized bone grafts allow living bone tissue to be transplanted to replace a bone defect. The use of vascularized bone grafts requires microvascular dissection and attachment to a recipient site artery and vein, whereas rotational or pedicle grafts are moved, while still attached to their blood supply, to a new site. Conventional nonvascularized bone grafts heal by resorption and creeping substitution. The major benefits of vascularized bone grafts are more rapid and complete incorporation of the graft which provides immediate structural support, the ability of the transplanted (living) bone to form new bone, and the addition of new blood supply to the recipient area. The technique of the free vascularized fibula transplantation is described.

Adult↗
PubMed1993

Ulnar translation of the carpus in rheumatoid arthritis: an analysis of five determination methods.

Five x-ray methods of assessing ulnar translation of the carpus were compared to each other. Overall, we found the uncompensated semiquantitative method proposed by Gilula et al. to be the most practical and the best method with a sensitivity index of 82%, a specificity index of 88%, an accuracy of 87%, and an interobserver correlation of 90%. The method, however, decreased in specificity and accuracy when a corrective formula was applied to adjust the ulnometacarpal angle to zero degrees deviation. Our conclusion is that the sensitivity indices are relatively low for all methods, and underdiagnosis may occur. At present the semiquantitated method of Gilula et al. is the most practical, with the highest sensitivity index, and is recommended as a screening tool for assessment of ulnar translation of the carpus.

Adult↗
PubMed1993

Comparative fatigue strengths and stabilities of metacarpal internal fixation techniques.

To study quantitative differences in the fatigue strength and stability obtained with 5 types of internal fixation of metacarpal fractures, 105 preserved human metacarpals were cyclically tested in bending, torsion, and axial loading after oblique osteotomies of the metacarpal and internal fixation. The dorsal plate with lag screw was superior in all modes, followed by the two dorsal lag screws, crossed Kirschner wire tension banding, and intramedullary Kirschner wire fixation. The five intramedullary and the paired intramedullary Kirschner wire fixations were not statistically different. The fatigue life of the plate fixation was significantly larger in bending (1.5 times), torsion (1.6 times), and axial loading (2.5 times) than the second strongest fixation, two dorsal lag screws. Its initial rigidity was significantly higher in axial loading (1.5 times) but was not statistically different in bending and torsion.

Fracture Fixation, Internal↗
PubMed1991

Stress computed tomography analysis of the distal radioulnar joint: a diagnostic tool for determining translational motion.

Sixteen distal radioulnar joints in eight normal volunteers (five females, three males) were evaluated by use of a special stress computed tomography technique. The mean palmar and dorsal translational motion was 2.2 millimeters +/- 1.6 and 1.0 millimeters +/- 0.9, respectively, for the combined group. The mean stress range was 3.3 millimeters +/- 1.4 for the entire group. There was no statistical difference for the amount of motion noted on palmar stress, dorsal stress, and the stress-range between males and females. There was also no statistical difference between contralateral sides and hand dominance. The average contralateral difference was 0.1 millimeters, 0.1 millimeters, and 0.3 millimeters for palmar, no stress, dorsal studies, respectively. We conclude the limits of maximal translational motion of the distal radioulnar joints can be determined by computed tomography stress analysis. Unilateral analysis allows the determination of frank instability. However, bilateral analysis allows the determination of frank instability, subluxation, and dynamic instability. This technique is useful in evaluating distal radioulnar joint stability.

Adolescent↗