Wrist Postures While Typing on a Standard and Split Keyboard

Fifty experienced typists participated in a laboratory based repeated measures study with two factors: keyboard height (three) and keyboard configuration (three). The work surface heights tested were 63, 67 and 71 cm. The three keyboard configurations tested were: standard (Apple Extended™), alternative keyboard A (Microsoft Natural Keyboard) and alternative keyboard B (equivalent to Natural Keyboard with Leveler™ extended). Wrist and forearm posture data was acquired using electronic goniometers during 10 minutes of typing at each keyboard/height level. Across all heights tested, wrist extension, wrist ulnar deviation, and forearm pronation were statistically significantly closer to neutral when using alternative keyboard B than when using the standard keyboard.

Changes in wrist postures during a prolonged typing task

Twenty experienced typists participated in a laboratory based study to determine whether wrist and forearm postures changed over a 4 hour period of intensive keyboard use. Subjects were randomly assigned to use a conventional keyboard or a fixed split keyboard. Posture data was acquired using electrogoniometers after a 10 warm-up period and at the end of each hour. Wrist and forearm postures did not change significantly over the four hour period among subjects using the split geometry keyboard. On the conventional keyboard, all joint postures were stable except right wrist extension and left forearm pronation. The right wrist extension increased by 5° over the four hour period (p=.002) and left pronation decreased by approximately 9° (p=.001). Wrist postures among typists exposed for the first time to a split keyboard remained constant throughout a four hour period of intensive typing. On the conventional keyboard, some postures drifted over the four hour period.

Spontaneous infectious discitis in adults

PURPOSE

In adults, discitis most frequently follows spinal surgery. We report 16 adult patients with spontaneously occurring infectious discitis and compare them with an additional 52 patients abstracted from the literature. Infecting organisms, predisposing factors, imaging modalities, and response to therapy are described.

PATIENTS AND METHODS

The medical records of adult patients treated for infectious discitis of a community hospital during the past 10 years were reviewed. Postoperative spine patients and patients with primary osteomyelitis were excluded. Sixteen patients were identified with spontaneous primary infection of the disc space. The particulars of comorbid conditions, infection organisms, site of culture, and response to antibiotic therapy were noted and compared to 52 additional cases of spontaneous discitis reported in the literature since 1980.

RESULTS

A wide variety of infecting organisms was identified as causing spontaneous discitis, in contrast to previous reports of both postoperative discitis and spontaneous discitis. Nine of 10 patients with positive disc cultures had negative blood cultures. Appropriate antibiotics were curative in all patients but 1, regardless of the duration of symptoms. Nuclear imaging, computed tomography, and magnetic resonance imaging were all useful, although the last appears to be the most sensitive and specific imaging modality for detecting discitis.

CONCLUSIONS

Spontaneous infectious discitis is an uncommon cause of low back pain in adults. Nevertheless, it should be considered in any patient with acute or subacute pain. Elevated acute-phase reactants with appropriate imaging modality suggest the diagnosis. given the wide variety of infecting organisms identified, culture of blood and/or disc for the specific causative organism is critical to successful treatment outcome.

Usefulness of a pericardial friction rub after thrombolytic therapy during acute myocardial infarction in predicting amount of myocardial damage. The TAMI Study Group

To evaluate the clinical incidence and outcomes of patients with pericarditis after thrombolytic therapy, 810 patients were prospectively studied during acute myocardial infarction (AMI). Pericarditis was defined as the presence of a pericardial friction rub during the hospital course. Only 5% of patients developed a rub during AMI, a low percent compared with that in the prethrombolytic era. A pericardial friction rub more often occurred in the setting of an anterior wall AMI. Patients with, compared to those without, a pericardial friction rub had lower ejection fractions (45 vs 51%, p = 0.002); worse regional left ventricular function (-3.2 vs 2.7, standard deviation per chord); higher in-hospital mortality (15 vs 6%, p = 0.056); a higher frequency of power failure (83 vs 57%); a higher frequency of anterior wall location of the AMI (53% of cases, p = 0.002); and a higher frequency of 3-vessel disease. Therefore, although the frequency of a pericardial friction rub was low (5%) compared with that in the prethrombolytic era, its occurrence denotes more extensive myocardial damage with a worse clinical outcome. Perhaps with successful reperfusion of the infarct-related vessel, transmural myocardial necrosis is prevented and with it the development of pericarditis. Cardiac tamponade did not occur clinically in any patient who developed a pericardial friction rub.