Surgery – Diagnostic testing – Touch or pain response of skin
Reexamination Certificate
1999-06-08
2001-03-13
O'Connor, Cary (Department: 3736)
Surgery
Diagnostic testing
Touch or pain response of skin
Reexamination Certificate
active
06200272
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device used by health care providers for detecting a patient's loss of protective sensation. More particularly, it relates to an improved monofilament-type device used for this purpose.
BACKGROUND OF THE INVENTION
Protective sensation, or ability to feel pain, is the body's warning system that enables an individual to avoid injury and that alerts the individual when injury does occur. Certain neurological and other medical examinations require the detection of impaired or lost sensitivity. Such detection is particularly important for patients with certain diseases or disabilities. For example, nearly half of all diabetes patients in the United States develop diabetic neuropathy, a complication that suppresses a patient's ability to feel pain. Diabetic peripheral neuropathy is characterized by loss of protective sensation, which may be manifested as analgesia (absence of pain or touch sensitivity), hyposthesia (reduced sensitivity), weakness, or autonomic changes. Loss of protective sensation is that degree of sensory loss that permits cutaneous injury to occur without being perceived by the patient as painful.
When due to neuropathy, loss of protective sensation is a major permissive factor in the pathogenesis of foot injury, and often leads to ulceration, infection, and, potentially, amputation. These problems are significant: Approximately 15% of diabetes patients sustain foot or leg ulcers, and may reacquire them in the absence of preventive and protective intervention. In addition, diabetic foot ulcers account for more than 20% of total hospital days for patients with diabetes, and they are the leading cause of hospital admissions for diabetic patients. Approximately 50% of all nontraumatic amputations in the United States are caused by complications from diabetes.
Routine testing for loss of protective sensation is critical, particularly for at-risk patients, such as those with diabetes. Prior art devices, however, are cumbersome and relatively expensive, and thus hinder such routine testing. For example, the device disclosed by Low et. al, U.S. Pat. No. 3,662,744, issued May 16, 1972, telescopically extends and retracts a monofilament. This device requires the health care practitioner to turn a knob to extend the monofilament each time the device is used, to ensure the proper length of monofilament is extended from the device, and to turn the knob to retract the monofilament when done. Because the length of monofilament extended from the device is variable, the health care practitioner has difficulty knowing how much force is being exerted by the monofilament on the patient. The device also has many moving parts, and thus is relatively costly to manufacture.
The Semmes-Weinstein esthesiometer, which currently is in widespread use, also has disadvantages. The Semmes-Weinstein device consists of a monofilament that is permanently attached at a 90 degree angle to the end of a plastic rod. The monofilament is always exposed, and thus is prone to damage. To compensate, the device generally is kept in a protective case in a drawer. The result is that the device is often not conveniently accessible to the health care provider, and thus is not used on a consistent basis.
Other devices solve some of the problems of the prior art by protecting the monofilament from damage, but these devices are somewhat bulky and are therefore more difficult than necessary for a health care practitioner to carry. One device, disclosed in Applicant's application Ser. No. 08/719,167, discloses a device wherein the probe is protected within a handle member when not in use.
There is need for a device for evaluating protective sensation that is convenient to carry and easy to operate, thereby enabling health care practitioners to evaluate routinely whether their patients have lost protective sensation. Such a device preferably also will be inexpensive, small, lightweight, and sized to fit within a health care practitioner's pocket.
SUMMARY OF THE INVENTION
In one embodiment, the invention is a device for evaluating protective sensation, comprising a probe and a folding card attached to the probe, such that a portion of the probe extends from the folding card when the folding card is in a first position. In this embodiment, the folding card may be folded such that the probe is enclosed by and protected by the folding card. This embodiment may be advantageous in that the probe may be protected by the folding card and hence out of harm's way when the folding card is folded to enclose the probe.
Another embodiment of the invention is a device for testing protective sensation of a patient's skin, comprising a monofilament probe and a folding card attached to the monofilament probe adjacent a first crease, wherein the monofilament probe extends outwardly from the folding card when the folding card is folded in a first position, and the monofilament probe is enclosed and protected by the folding card when the folding card is folded along the first crease in a second position. Much like the previous embodiment, the folding card may be folded in a position such that the monofilament probe is protected by the folding card, such that it will not be damaged easily.
Each of the embodiments described above offer the advantage of providing a lightweight device that may be carried easily by a health care practitioner to measure the protective sensation of a patient's skin. The device may easily fit into a health care practitioner's pocket, wallet, or purse, and in one embodiment the folding card may be folded into a card the size of a typical business card. Each embodiment also offers the advantage of folding into a form that protects the probe when the device is not in use.
These and other objects and advantages of the present invention will become apparent with reference to the drawings, the description of the preferred embodiment, and the appended claims.
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Curative Health Services, Inc.
Dorsey & Whitney LLP
O'Connor Cary
Wingood Pamela
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