Epidural needle having a distal flare
First Claim
1. In a patient having ligamentous structures, a ligamentum flavum ventral to the ligamentous structures, and an epidural space ventral to the ligamentum flavum, a method for injecting a material into the epidural space, the method comprising:
- providing an epidural needle having a shaft, a lumen therethrough, a distal tip, and a bulge beginning proximally no more than about 6 millimeters from the distal tip;
advancing the distal tip distally through the ligamentous structures while sensing a first resistance to advancement;
continuing advancing the distal tip as the bulge penetrates the ligamentum flavum while sensing a second resistance to advancement greater than the first resistance to advancement;
stopping further advancement after a decrease in resistance is sensed relative to the second resistance to advancement; and
injecting the material through the lumen and into the epidural space.
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Accused Products
Abstract
Apparatus and methods for injecting fluid into the epidural space. An improved epidural needle or cannula is provided having a distal bulge or flare located within a few millimeters of the distal tip. The distal flare provides an increased resistance to penetration while the needle is penetrating the ligamentum flavum, and a decrease in resistance to penetration after the distal flare has successfully penetrated the ligamentum flavum. In a preferred embodiment, the distal bulge begins proximally at a distance of less than about 6 millimeters from the distal tip. The epidural needle according to the present invention preferably has the distal bulge or flare beginning proximally at a distance from the distal tip of less than the width of the epidural space. In one method according to the present invention, an epidural needle having a distal flare is advanced to the ligamentum flavum, advanced further through the ligamentum flavum at a perceived higher resistance to travel, until a decrease in resistance to travel is perceived, at which time the distal flare has penetrated the ligamentum flavum into the epidural space, at which time further advancement is stopped.
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Citations
9 Claims
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1. In a patient having ligamentous structures, a ligamentum flavum ventral to the ligamentous structures, and an epidural space ventral to the ligamentum flavum, a method for injecting a material into the epidural space, the method comprising:
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providing an epidural needle having a shaft, a lumen therethrough, a distal tip, and a bulge beginning proximally no more than about 6 millimeters from the distal tip;
advancing the distal tip distally through the ligamentous structures while sensing a first resistance to advancement;
continuing advancing the distal tip as the bulge penetrates the ligamentum flavum while sensing a second resistance to advancement greater than the first resistance to advancement;
stopping further advancement after a decrease in resistance is sensed relative to the second resistance to advancement; and
injecting the material through the lumen and into the epidural space. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a patient having ligamentous structures, a ligamentum flavum ventral to the ligamentous structures, and an epidural space ventral to the ligamentum flavum, a method for disposing a medical device distal tip into the epidural space, the method comprising:
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providing the medical device having the distal tip, a shaft, and a bulge beginning proximally within about 6 millimeters from the distal tip;
advancing the distal tip distally through the ligamentous structures while sensing a first resistance to advancement;
continuing advancing the distal tip as the bulge penetrates the ligamentum flavum while sensing a second resistance to advancement greater than the first resistance to advancement;
stopping further advancement after a decrease in resistance is sensed relative to the second resistance to advancement, such that the medical device distal tip is disposed within the epidural space.
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9. In a patient having ligamentous structures, a ligamentum flavum ventral to the ligamentous structures, and an epidural space ventral to the ligamentum flavum, a method for injecting a material into the epidural space, the method comprising:
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providing an epidural needle having a shaft, a lumen therethrough, a distal portion, a distal tip, and a bulge disposed in the distal portion;
advancing the distal tip distally through the ligamentous structures while sensing a first resistance to advancement;
continuing advancing the distal tip as the bulge penetrates the ligamentum flavum while sensing a second resistance to advancement greater than the first resistance to advancement;
stopping further advancement after a decrease in resistance is sensed relative to the second resistance to advancement; and
injecting the material through the lumen and into the epidural space.
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Specification