Therapeutic limb covering using hydrostatic pressure

#The present invention relates to devices and methods for the treatment of chronic swelling.

#Chronic swelling of a limb is a medical condition that results in pain, tissue breakdown and immobility for many patients. Such swelling is often caused by venous insufficiency or other disease such as lymphedema. In the case of venous insufficiency or venous stasis, the venous system of the extremities, particularly the lower extremities, experiences reduced blood flow. The reduced blood flow results from venous dysfunction in the extremity that limits the effective return of blood from the extremity back to the heart. The problem is exacerbated in lower extremities due to the effect of gravity, which must be overcome to move the blood back to the heart. However the arms are also susceptible to chronic swelling conditions such as may be caused by cancer of the lymph glands or post-mastectomy radiation treatment.

#A common treatment for chronic swelling is the application of external pressure to increase tissue pressure in the region. This treatment decreases the swelling and improves tissue oxygenation, thereby allowing tissue to heal. In applying pressure to the leg, it is desirable to apply the highest pressure at the ankle and gradually decrease the pressure that is applied toward the top of the lower leg. However applying pressure to the limb can be problematic for a patient that also suffers from poor arterial perfusion. Poor arterial perfusion is caused by insufficient blood supply and blood has difficulty reaching the limb, not just returning from the limb as with venous insufficiency. Applying pressure to the limb serves to help prevent blood from ever reaching the limb. Therefore, traditional methods of treating chronic swelling cannot be used for patients with poor arterial perfusion.

#The foregoing and other objects and advantages of the invention will be appreciated more fully from the following further description thereof, with reference to the accompanying diagrammatic drawings wherein:

#FIG. 1 is a side view of a therapeutic limb covering;

#FIG. 2 is a front view of a therapeutic limb covering;

#FIGS. 1 and 2 show a therapeutic limb covering according to the present invention. FIG. 1 shows a limb covering configured as a boot 10 configured to fit about a patient's foot and lower leg. The boot comprises a calf portion 12 and a foot portion 14. The covering is donned about a patient's foot and lower leg such that the toes protrude from toe opening 16, and the calf portion 12 extends up the lower leg such that calf opening 18 is positioned just below a patient's knee 20 (as best seen in FIG. 4). The foot portion 14 is oriented substantially perpendicular to the calf portion 12 to mimic the orientation of the foot and leg under most circumstances, but the entire covering is made from flexible materials so that the orientation between the foot and leg remains flexible and capable of movement.

#FIG. 3 is a sectional view of the boot shown in FIG. 1 taken along the line 3-3 of FIG. 1. The limb covering comprises a flexible but substantially non-distensible outer layer 22 joined to a flexible and distensible inner layer 24 to define a liquid tight bladder 26 therebetween. The bladder is filled with any convenient liquid, such as water, to apply pressure to the limb 19 about which the covering is worn. It is noted that other suitable liquids may have densities that are different than water to provide a different resulting pressure such include salt water or gel substances.

#The distensible inner layer is elastic and expands under the pressure of the liquid in the bladder, while the inelastic outer layer 22 retains the shape of the covering so that it remains properly positioned around the limb. Liquid transfer valve 62, bonded to the calf portion 12 and in liquid communication with the bladder 26 provides sealable port through which liquid may be added to or removed from the bladder.