US 4,919,653 AGranted

Device for locating the epidural space

OwnerAntonio E. Martinez, Eduardo C. Garciainventors

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Abstract

The device for locating the epidural space being proposed is based on the depression existing at that space. It consists of a circuit and a canula with a corresponding coaxial needle. Once the circuit is energized, a puncture is carried out with the canula up to the surroundings of the yellow ligament. The canula is fixed at this position by means of a fixer element which is displaced along the canula up to the patient's back. The needle is inserted into the canula and by careful manual force or punching it continues until reaching the epidural space. When that happens, the circuit is triggered due to the existing depression at the epidural space, one or more alarms or signals and an electromagnet being thereby activated, the latter attracting the needle and a sleeve into which it is coaxially positioned. By frictional engagement to one another, the needle and sleeve move farther through the canula in response to the activated electromagnet. With the simultaneous displacement of the sleeve and of the needle, the needle reaches the center of the epidural space, situated 2 mm away from the circuit triggering position, this being the maximum sleeve displacement distance.

Claims6

Dependent claims

A device for locating the epidural space, for introducing into it anesthetics, analgesics, narcotics, and the like, by injection with a needle or a catheter, essentially characterized by comprising a canula provided with a duct therethrough and a handle inside which an electromagnet is situated and at the rear part of which there is a retaining element that also works as a stop of a sleeve axially situated in the handle, the inner surface of the sleeve being considerably corrugated;

the canula further including a fixation element adjustable along the canula in order to prevent the canula from penetrating beyond the yellow ligament, thereby allowing the axial and comfortable introduction through the sleeve and the canula duct of a conically pointed needle with lateral outlet, the needle having a corrugated outer surface portion capable of being inserted into the sleeve by the electromagnet action, which is activated by a circuit operatively connected to the device capable of detecting the depression existing in the epidural space by the use of a pressure sensor operatively connected to the needle, which transforms the pressure signal into an electric signal, which is passed on to an electric circuit, so that, if there is a difference between the atmospheric pressure and the detected one, a transistorized switch will close the circuit and the above mentioned electromagnet and one or both of a sound and visual alarm will be activated.

Dependencies are inferred from the claim text.