The effect of military load carriage on ground reaction forces.

Load carriage is an inevitable part of military life both during training and operations. Loads carried are frequently as high as 60% bodyweight, and this increases injury risk. In the military, load is carried in a backpack (also referred to as a Bergen) and webbing, these combined form a load carriage system (LCS). A substantial body of literature exists recording the physiological effects of load carriage; less is available regarding the biomechanics. Previous biomechanical studies have generally been restricted to loads of 20% and 40% of bodyweight, usually carried in the backpack alone. The effect of rifle carriage on gait has also received little or no attention in the published literature. This is despite military personnel almost always carrying a rifle during load carriage. In this study, 15 male participants completed 8 conditions: military boot, rifle, webbing 8 and 16 kg, backpack 16 kg and LCS 24, 32 and 40 kg. Results showed that load added in 8 kg increments elicited a proportional increase in vertical and anteroposterior ground reaction force (GRF) parameters. Rifle carriage significantly increased the impact peak and mediolateral impulse compared to the boot condition. These effects may be the result of changes to the vertical and horizontal position of the body's centre of mass, caused by the restriction of natural arm swing patterns. Increased GRFs, particularly in the vertical axis, have been positively linked to overuse injuries. Therefore, the biomechanical analysis of load carriage is important in aiding our understanding of injuries associated with military load carriage.

Quality-of-life effect of tonsillectomy in a young adult group.

BACKGROUND: To examine the quality of life after tonsillectomy in a young adult group with chronic or recurrent tonsillitis. METHODS: Retrospective survey of patients aged 15-25 years who underwent tonsillectomy for chronic or recurrent tonsillitis in 2002 or 2003. The Glasgow Benefit Inventory was mailed to patients who were selected from two private general otolaryngology practices. RESULTS: Participants had an overall benefit from the procedure as well as improvement in their general well-being and physical health. A benefit in social function was not imparted. CONCLUSION: Tonsillectomy in a young adult group results in significant improvement in overall quality of life, physical health and general well-being.

Initial subjective load carriage injury data collected with interviews and questionnaires.

This study aimed to identify the types, incidence, and causes of any potential load carriage injuries or discomfort as a result of a 2-hour, forced-speed, treadmill march carrying 20 kg. Subjective load carriage data were collected, through both interviews and questionnaires, from relatively inexperienced soldiers after a period of load carriage. Results from the study showed that the upper limb is very susceptible to short-term discomfort, whereas the lower limb is not. The shoulders were rated significantly more uncomfortable then any other region, and blisters were experienced by approximately 60% of participants. Shoulder discomfort commences almost as soon as the load is added and increases steadily with time; however, foot discomfort increases more rapidly once the discomfort materializes. In conclusion, early development of shoulder pain or blisters may be a risk factor for severe pain or noncompletion of a period of prolonged load carriage.

Airway fire during tracheotomy.

We report a case of airway fire during surgical tracheotomy using diathermy for the incision into the trachea. A literature review of airway fire during tracheotomy was carried out, and the management of airway fire is discussed. Recommendations are made to prevent this adverse outcome.

The effect of single- or multiple-layered garments on interface pressure measured at the backpack-shoulder interface.

Experiments were aimed at determining whether interface pressure measurements are a true reflection of skin contact pressure when made over different layers of clothing. Interface pressures were recorded at the skin interface and above clothing layers, with 11 participants wearing 10 different clothing combinations. The clothing used was standard issue British military clothing, including body armour (without ballistic plate). Participants wore both single and multiple clothing layers whilst walking on a treadmill carrying a loaded backpack (23.5 kg, British military issue). Results showed no significant differences (p=>0.05) in pressure between different clothing layers either singly, or worn in multiple. In conclusion, the soldier (or leisure user) will gain no or very little relief from applied pressure by wearing garments, even in layers, when carrying a backpack. Also, the findings suggest that interface pressure may adequately be assessed using a sensor placed above the clothing layer(s) rather than at skin surface.

Otogenic cranial base osteomyelitis: a proposed prognosis-based system for disease classification.

OBJECTIVES: To review the presentation, microbiology, and long-term results of treating otogenic cranial base osteomyelitis to develop a prognosis-based disease classification system. PATIENTS AND METHODS: Thirty-eight patients with otogenic cranial base osteomyelitis treated between 1989 and 2002 were studied. Patient demographics, presentation, pathogens, details of therapy, and disease-specific survival were recorded. Patients were stratified using Technetium-99 single-photon emission computerized tomography (SPECT) at presentation into 4 grades: I, mild uptake; II, focal mastoid/temporal bone uptake not reaching midline; III, petrous temporal bone uptake reaching midline; and IV, uptake crossing midline, involving the contralateral temporal bone. Actuarial analysis was used to identify prognostic factors. RESULTS: There were 27 men. The average age at presentation was 65 +/- 16 years (range, 19-95 yr). The median age-adjusted Charlson comorbidity score was 5, and 63% of patients were diabetic. The most common presenting symptoms were pain and otorrhea, and 8 patients had cranial nerve neuropathy. Pseudomonas aeruginosa was the most common bacterial pathogen (n = 28; 74%), and 9 patients had fungal or mixed infections. On average, antibiotics were administered for 161 days, and 6 patients had concomitant surgery. The average follow-up was 33 months, and 3-year disease-specific survival was 76%. Univariate predictors of survival were the SPECT grade, fungal/mixed infections, Charlson score, immune compromise, and cranial nerve neuropathy. The only independent predictor of survival on multivariate Cox regression was the SPECT stage at presentation. CONCLUSION: Cranial base osteomyelitis is associated with significant morbidity and mortality and requires prolonged treatment. Long-term outcome can be predicted from the initial SPECT scan.

Influence of carrying heavy loads on soldiers' posture, movements and gait.

Military personnel are required to carry heavy loads whilst marching; this load carriage represents a substantial component of training and combat. Studies in the literature mainly concentrate on physiological effects, with few biomechanical studies of military load carriage systems (LCS). This study examines changes in gait and posture caused by increasing load carriage in military LCS. The four conditions used during this study were control (including rifle, boots and helmet carriage, totalling 8 kg), webbing (weighing 8 kg), backpack (24 kg) and a light antitank weapon (LAW; 10 kg), resulting in an incremental increase in load carried from 8, 16, 40 to 50 kg. A total of 20 male soldiers were evaluated in the sagittal plane using a 3-D motion analysis system. Measurements of ankle, knee, femur, trunk and craniovertebral angles and spatiotemporal parameters were made during self-paced walking. Results showed spatiotemporal changes were unrelated to angular changes, perhaps a consequence of military training. Knee and femur ranges of motion (control, 21.1 degrees +/- 3.0 and 33.9 degrees +/- 7.1 respectively) increased (p < 0.05) with load (LAW, 25.5 degrees +/- 2.3 and 37.8 degrees +/- 1.5 respectively). The trunk flexed significantly further forward, confirming results from previous studies. In addition, the craniovertebral angle decreased (p < 0.001) indicating a more forward position of the head with load. It is concluded that the head functions in concert with the trunk to counterbalance load. The higher muscular tensions necessary to sustain these changes have been associated with injury, muscle strain and joint problems.