Surgery – Instruments – Means for removing tonsils – adenoids or polyps
Reexamination Certificate
2000-05-16
2001-11-20
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Means for removing tonsils, adenoids or polyps
Reexamination Certificate
active
06319260
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a method of endoscopic mucosal resection. More particularly it relates to a method of endoscopic mucosal resection performed easily and reliably with assistance of a biocompatible mucopolysaccharide having no anticoagulant activity, and to a local injection preparation used therefor.
(2) Description of the Related Art
Endoscopic mucosal resection (hereinafter abbreviated to “EMR”) has been widely accepted as a standard procedure for early-stage neoplastic lesions of gastrointestinal tracts. Recently, various modifications of this EMR technique have been introduced. Currently the accepted EMR techniques include a strip-biopsy method or a lift-and-cut EMR, an endoscopic resection after local injection of saline into the submucosal layer, an endoscopic double-snare polypectomy, an EMR using an over-tube, strip-biopsy using two small-diameter endoscopes, an EMR with a cap-fitted panondoscope, and an EMR using a ligation device.
With the improvements in endoscopic resection techniques, good results have been obtained In terms of local cure and long-term outcome after resection. However, these methods still have technical limitations. For example, the strip-biopsy method requires a two-channeled endoscope and it is not suitable for lesions located on the lesser curvature, posterior wall, and cardia of the stomach. With methods using a translucent cap or a ligation device, the size of the resectable mucosa is limited depending upon the size of the device. Further, the endoscopic view is lost by “red-out” while trapping a lesion in these devices. The EMR using an over-tube as well as the strip-biopsy using two-small diameter endoscopes are cumbersome.
In an EMR technique, an affected mucosal tissue is observed with an endoscope and trapped by a snare to perform resection. The affected mucosal tissue does not protrude to a great extent and the surface of mucosa is slippery. Therefore EMR is usually accompanied by technical difficulties, namely, complete removal of the affected mucosa tissue is difficult to attain and complication such as bleeding or perforation sometimes occurs due to unsuccessful operation. To cope with the difficulties, an improved endoscopic resection technique has been proposed wherein endoscopic resection is performed after local injection of normal saline into the submucosal layer of an affected mucosa tissue. However, a problem arises in that the injected saline diffuses quickly with consequent disappearance of the protrusion.
Another proposal has been made wherein hypertonic saline-epinephrine (HSE) or 504 glucose is used as an alternative to the normal saline for preventing or minimizing bleeding during BMR [Hirao M, Masuda K, Asanuma T. Naka H. Noda K, Matsuura K, et al, Endoscopic resection of early gastric cancer and other tumors with local injection of hypertonic saline-epinephrine, Gastrointest Endosc, 1988, 34:264-9; and Makuuch H, Mitomi H, Machimura T, Mizutani S, Shimada H, Sugano K, et al, Endoscopic mucosal resection for early esophageal cancer by the EEMR-tube method, Stomach Intent., 1993;28:153-9]. This proposal still has a problem such that the injected HSE solution or HSE solution containing 50% glucose is emitted from an opening of the mucosa tissue when incised by a needle knife, with consequent disappearance of the protrusion. Further, the hypertonic saline has a histoaffective effect and the problem of complication of bleeding and/or perforation is not solved.
SUMMARY OF THE INVENTION
In view of the foregoing, a primary object of the Invention is to provide a method of EMR performed easily, safely and reliably.
Another object is to provide a local injection preparation used for the method of BM.
In one aspect of the present invention, there is provided a method of endoscopic mucosal resection, which comprises injecting a local injection preparation containing a biocompatible mucopolysaccharide having no anticoagulant activity, preferably sodium hyaluronate, into the submucosal layer of an affected mucosal tissue to create mucosal elevation, and, trapping the thus-elevated mucosal tissue with a snare to perform resection.
In another aspect of the present invention, there is provided a local injection preparation comprising (i) a biocompatible mucopolysaccharide having no anticoagulant activity, preferably sodium hyaluronate, and (ii) a hemostat or angiotonic.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The EMR technique according to the present invention is characterized as injecting a local injection preparation comprising biocompatible mucopolysacoharide having no anticoagulant activity into the submucosal layer of an affected tissue to create mucosal elevation.
The benefits of the present invention are summarized as follows.
(1) The mucopolysaccharide solution injected into the submucosal layer is not readily diffused, and thus, the elevations made by the injections are steep and remain unchanged for a long time.
(2) Even when the elevated mucosa is partly incised, the injected mucopolysaccharide solution is not readily emitted and the elevated mucosa remains unchanged, and consequently the incision can be safely continued. This benefit is not obtainable with physiological saline, hypertonic saline or 50% glucose.
(3) Although the mucopolysaccharide solution has a high viscosity, its osmotic pressure is not high. Therefore, the mucopolysaccharide solution in not injurious to the tissue and possesses a high safety. EMR can be safely performed even for the colon with a reduced wall thickness. This makes a striking contrast with hypertonic saline or hypertonic saline containing 504 glucose, which Is difficult to use in EMR for the colon because of a considerable risk of perforation.
(4) The mucopolysaccharide solution exhibits a hemostatic affect through mechanical pressure against blood vessels in the submucosal tissue where the solution is injected. Where a hemostat or angiotonic such as epinephrine is incorporated in the mucopolysaccharide solution, the antistatic effect is enhanced to an amazing extent. It is presumed that a hemostat or angiotonic is dissolved in the viscous solution and remains in the injected solution, thus enhancing durability of the hemostat effect. The hemostat effect in safe as contrasted with that manifested by ethanol or hypertonic saline, utilizing tissue injury.
As preferable examples of the mucopolysaccharide having no anticoagulant activity, there can be mentioned hyaluronic acid and phamaceutically acceptable salts of hyaluronic acid, and chondroitin sulfate. The mucopolysaccharide used in the invention broadly includes not only biocompatible mucopolysaccharide having no anticoagulant activity in a narrow sense, but also derivatives thereof such as a crosslinked product of hyaluronic acid or its salt, and a composite of hyaluronic acid or its salt, such as cartilage proteoglycan, and a compound containing a major part of the mucopolysaccharide.
More preferable examples of the mucopolysaccharide are alkali metal salts of hyaluronic acid, such as sodium hyaluronate. Hyaluronic acid is a biocompatible glycosaminoglycan having no anticoagulant activity that is widely found in connective tissues of mammalians. It is a thick substance with high viscosity and a marked ability to retain water. Sodium hyaluronate exhibits a hemostatic effect due to its high viscosity and high adhesion to the tissue an well an a thickening effect. Sodium hyaluronate is neither antigenic nor toxic to human bodies, and is already approved for intrajoint injections for osteoarthritis in Japan. Hyaluronic acid and its salts preferably have an average molecular weight of 20,000 to 4,000,000, and more preferably 600,000 to 1,200,000.
The local injection preparation is an aqueous solution containing sodium hyaluronate at a concentration giving an injection preparation having a viscosity suitable for an endoscopic submucosal injection. The higher the concentration of sodium hyaluronate In the injection preparation or the higher the molecular weight of sod
Nixon & Vanderhye
Philogene Pedro
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