Biomedical subjects

V Tan

Publications and source records attributed to V Tan.

25 records · Page 2Linked to original sources

PubMed1998

Carry it on the bad side!

Patients with diseased hips often must carry objects while walking, yet they are rarely instructed which hand to use because little has been published on the subject. We sought to evaluate the situation mathematically by determining the hip forces that result when a load is carried in the ipsilateral versus the contralateral hand. Using a free-body diagram of single-leg supported stance, we found that when a load was carried in the contralateral hand, the resultant forces on the hip were increased considerably. Conversely, when the weight was carried in the ipsilateral hand, the forces were actually lower than when no weight was carried at all. Thus, carrying a weight on the opposite side resulted in hip forces that were substantially greater than when the weight was carried on the same side.

Functional Laterality↗

PubMed1998

Results of thoracoscopic sympathectomy for 96 cases of palmar hyperhidrosis.

From August 1996 to August 1997, we performed thoracoscopic sympathectomy for 96 cases of palmer hyperhidrosis. The patients' ages were from 22 to 58 years old (mean age: 28; gender ratio: male/female: 3/2). Most of them were students, workers or clerks. The patients were divided in two series: in 61 patients, the sympathetic chain before the 2nd to 4th ribs was removed in the lateral approach with a 3 hole procedure. In 35 patients, the 2nd portion of the sympathetic chain was destroyed (by electric cauter) in the posterior approach with a 2 hole procedure. The results were almost the same in the first series (all cases have a fair benefit), but in the second series, some advantages may be useful for therapy, i.e no need to turn the patients, severe compensation sweating is minimized (from 4% ==> 0%) and the amount of holes is reduced.

Adrenergic Fibers↗

PubMed1997

Goal setting as a predictor of return to work in a population of chronic musculoskeletal pain patients.

To assess prospectively the association between personal attributes, vocational factors, and the return to work outcome for patients with chronic, nonmalignant, musculoskeletal pain, we assessed return to work (RTW) motivation though an open-format listing of treatment goals in 59 chronic pain patients admitted to a university pain management program. Patients were then followed (average of 17.9 months) in the posttreatment period to determine whether they had in fact returned to employment. Results indicated that a number of pretreatment factors predicted future employment status in this patient population. Age, marital status, education and decreased length of unemployment were predictive of RTW outcome. Overall, RTW goal was the single best predictor of return to work outcome. In contrast, increased number of premorbid jobs, compensation status, patient's race and sex were not predictive. The present study suggests that the assessment of an individual's motivation as defined by goal-setting may be a key factor in predicting a favorable outcome in this typically refractory population of patients.

Adult↗

PubMed1995

Comparison of the kinetic fibrinogen assay with the von Clauss method and the clot recovery method in plasma of patients with conditions affecting fibrinogen coagulability.

A Kinetic Fibrinogen Assay (KFA), a method based on the kinetic reaction of the developing fibrin clot, was used to determine fibrinogen concentration in plasma. Two other methods employing different quantification principles were used for comparison: the von Clauss method and the procedure measuring protein concentration in an isolated and washed plasma clot (World Health Organization [WHO] method). All three methods quantified functional thrombin-coagulable fibrinogen. Plasma specimens were obtained from three groups of patients: those with liver disease and those taking either coumarin derivative or heparin. In all of these conditions, there are deviations from the normal process of fibrin clot formation. The KFA method yielded results that were consistent and provided excellent precision and accuracy allowing quantification of plasma fibrinogen in the range of 70-800 mg/dL (2-23.5 microM). The determination of fibrinogen by the KFA method was not adversely affected using plasma from patients treated with heparin and those undergoing coumarin therapy. Statistical analysis of the results indicated that the KFA method compared very favorably with the von Clauss and WHO methods. In assessing the clinical utility of each method, the WHO method was found to be labor intensive and time consuming; therefore, not suitable for routine use in a clinical laboratory. The von Clauss method required a trained laboratory technician and some laboratory manipulations. The KFA method was not only reliable and accurate, but also fully automated, making it the easiest and the fastest to perform routinely.

Anticoagulants↗

PubMed1992

Histoplasmosis of the central nervous system.

Histoplasma capsulatum infection of the central nervous system is extremely rare in the United Kingdom partly because the organism is not endemic. However, because the organism can remain quiescent in the lungs or the adrenal glands for over 40 years before dissemination, it increasingly needs to be considered in unexplained neurological disease particularly in people who lived in endemic areas as children. In this paper a rapidly progressive fatal myelopathy in an English man brought up in India was shown at necropsy to be due to histoplasmosis. The neurological features of this infection are reviewed.

Adrenal Glands↗

PubMedDate not supplied

The effect of articular malposition after total shoulder arthroplasty on glenohumeral translations, range of motion, and subacromial impingement.

The articular surface of the normal humeral head has a variable posterior and medial offset with respect to the central axis of the humeral shaft. Recreation of the normal humeral head shaft offset is postulated to be an important consideration during shoulder arthroplasty. However, the effect of humeral head malposition is unknown. The purpose of this study was to determine the effect of articular malposition after total shoulder arthroplasty on glenohumeral translation, range of motion, and subacromial impingement. Twenty-one human cadavers were dissected and tested with the use of an active or passive shoulder model. Range of motion and translation were recorded by means of an electromagnetic tracking device. The experiment was performed in 2 phases. For kinematics study, 11 cadaver shoulders were positioned both passively and actively from maximum internal rotation to maximum external rotation at 90 degrees of total elevation in the scapular plane. Three rotator cuff and 3 deltoid muscle lines of action were simulated for active joint positioning. Passive joint positioning was accomplished with the use of a torque wrench and a nominal centering force. The testing protocol was used for the natural joint as well as for 9 prosthetic head locations: centered and 2- and 4-mm offsets in the anterior, posterior, inferior, and superior directions. Repeated-measures analysis of variance was used to test for significant differences in the range of motion and translation between active and passive positioning of the natural joint as well as all prosthetic head positions. (2) For impingement study, 10 cadaver shoulders were used in a passive model, loading the tendons of the rotator cuff with a 30-N centering force. The humerus was passively rotated from maximum internal rotation (1500 Nmm) to maximum external rotation (1500 Nmm) by means of a continuous-recording digital torque wrench. Trials were performed with the use of centered, 4-, 6-, and 8-mm offset heads in the anterior, posterior, superior, and inferior positions before and after removal of the acromion and coracoacromial ligament. The relation between change in mean peak torque (with and without acromion), passive range of motion, and humeral head offset was analyzed by means of repeated-measures analysis of variance. In the kinematics study, total range of motion and all humeral translations were greater with passive joint positioning than with active positioning (P =.01) except for total superior-inferior translation and superior-inferior translation in external rotation. Anterior to posterior humeral head offset was associated with statistically significant changes in total range of motion (P =.02), range of internal rotation (P =.02), range of external rotation (P =.0001), and total anterior-posterior translation (P =.01). Superior to inferior humeral head offset resulted in statistically significant changes in total range of motion (P =.02), range of internal rotation (P =.0001), anterior-posterior translation during external rotation (P =.01), and total superior-inferior translation (P =.03). In the impingement study, there was a significant increase in torque from centered to 4-mm inferior offset (P =.006), 6-mm inferior offset (P <.001), and 8-mm inferior offset (P <.001). There was no significant increase in torque with superior, anterior, and posterior offsets. Glenohumeral motion significantly decreased from 129 degrees for centered head to 119 degrees for 8-mm superior (P =.002), 119 degrees for 8-mm anterior (P =.014), 118 degrees for 8-mm inferior (P <.001), and 114 degrees for 8-mm posterior (P =.001). Humeral articular malposition of 4 mm or less during prosthetic arthroplasty of the glenohumeral joint may lead to small alterations in humeral translations and range of motion. Inferior malposition of greater than 4 mm can lead to increased subacromial contact; offset of 8 mm in any direction results in significant decreases in passive range of motion. Therefore if subacromial contact is to be minimized and glenohumeral motion maximized after shoulder replacement, anatomic reconstruction of the humeral head-humeral shaft offset to within 4 mm is desirable.

Adult↗

PubMedDate not supplied

Well-leg compartment pressures during hemilithotomy position for fracture fixation.

OBJECTIVE: To evaluate the relationship between the well-leg compartment pressures and time during hemilithotomy position for fracture fixation. DESIGN: Prospective. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Ten patients who underwent intramedullary nailing of a fractured femur in the hemilithotomy position (with a well-leg holder). INTERVENTION: Continuous pressure monitoring was achieved with in-dwelling slit catheters inserted into the calf compartments of the well leg. Baseline measurements were obtained in the supine position. After the leg was placed in the hemilithotomy position, compartment pressures were monitored throughout surgery. MAIN OUTCOME MEASUREMENTS: Calf compartment pressures at baseline, during hemilithotomy position, and post-hemilithotomy were compared. The association between body mass index and compartment pressure was analyzed. RESULTS: A consistent pattern was observed between compartment pressures and time. The curve was that of a step function in which the pressure increased as soon as the leg was placed in the well-leg holder and remained elevated until the leg was taken down. The pressure jumped from a baseline of 9.2 to 27.3 millimeters of mercury (mm Hg) (p<0.0001). While in the hemilithotomy position, the leg pressure trended slightly upward. Once the leg was taken down, the pressure immediately returned to a near-baseline level of 8.1 mm Hg (p<0.0001). A significant correlation was also found between the body mass index and leg pressure (R2 = 0.713; F = 0.002). CONCLUSIONS: The use of the well-leg holder to maintain hemilithotomy position increases the calf compartment pressures dramatically and significantly. Therefore, we recommend avoiding this position for fracture fixation in at-risk patients.

Adolescent↗