[Assessment of male spinal alignment, while sleeping on side posture on soft, firm and custom made mattresses]

Ergonomic factors in sleep designing system will have direct effects on maintaining the spinal alignment during sleep. Studies show that a mattress with uniform stiffness cannot preserve the spine's natural posture. Using a mattress made of components with different stiffness can be considered as a solution for this problem. In this study, male spinal alignment has been assessed and compared on the hard and soft mattress along with a new type of mattress with different stiffness. The aim of this study was to evaluate the performance of this new type of mattress and determination of specific layout for each volunteer. After obtaining the dimensional survey data, 25 male volunteers were asked to take the side sleeping position on soft and very firm surfaces, with specific stiffness based on a predetermined protocol. The location coordinates of markers installed on the spinous process by optical detection methods were obtained in frontal plane. In the next step, spring-foam elements were arranged in a frame for each volunteer so that their spinal frontal plane can be close to their natural alignment. In side sleeping posture a c formed curvature appeared along the spinal frontal plane on stiff surface due to lack of support of the spine, and on the soft mattress, softness caused further sinking in the area of pelvis and loss of natural posture. But the arrangement of elements with different stiffness [custom made mattresses] maintained the natural posture of spine. The specific layouts for each volunteer were extracted. The results of this study showed that use of mattresses with custom arrangement is an appropriate way for maintaining optimum spinal alignment during sleep. Common mattresses with uniform stiffness do not have the ability to maintain the spine in a natural position during sleep. Determination of specific arrangements for side sleeping posture can help predict layout required for every individual in the future studies without performing a test

The foam mattress-back syndrome.

BACKGROUND: Many medical residents used to sleeping on cotton mattresses at home complain of mild to moderate back pain after sleeping on foam mattresses provided in the hospital and hostel rooms. OBJECTIVE: To determine the relationship of sleeping on foam mattress with the appearance of back pain in a 500 bedded multispecialty tertiary care hospital. METHODS: One hundred medical residents were interviewed for the appearance of backache after sleeping on 10 cm thick foam mattress provided to them in the hostels. Pain was scored over a visual analog scale of 10 cm. Effect of sleeping on a regular cotton mattress was assessed. RESULTS: Sixty-three (5 female residents) developed back pain on the morning of a night of sleep over the foam mattress. The pain was mostly of lower back and was not associated with any objective neurodeficit. Four residents on account of the backache reported thirteen episodes of absenteeism. Sixty-one residents had a relief of the pain on going home where they would sleep on regular cotton mattresses, only to recur after sleeping again on the foam mattress in the hospital/hostel. CONCLUSION: Sleeping on foam mattress is associated with the appearance of backache in medical residents which is reproducible and gets relieved after using regular cotton mattresses.