Method of soft tissue augmentation

Abstract

Particles according to the invention are made of a viscoelastic medium, are injectable gel particles, and have a size, when subjected to a physiological salt solution, in the range of from 1 to 5 mm. The particles are useful in a soft tissue augmentation implant. The implant comprises particles of a viscoelastic medium, wherein a major volume of the particles are injectable gel particles according to the invention. The implant is useful in a method of soft tissue augmentation in a mammal, including man, comprising subepidermal administration at a site in said mammal where soft tissue augmentation is desirable, of an implant according to the invention.

Description

[0001]This is a Division of application Ser. No. 11 / 090,141 filed on Mar. 28, 2005, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 60 / 560,258, filed Apr. 8, 2004. The disclosure of the prior applications is hereby incorporated by reference herein in their entirety.FIELD OF THE INVENTION[0002]The present invention relates to the fields of esthetics and plastic surgery, including cosmetic and reconstructive surgery. More specifically, the invention is concerned with a method of soft tissue augmentation in a mammal, including man. Moreover, the invention is directed to use of particles of a viscoelastic medium for the manufacture of a medicament for therapeutic soft tissue augmentation in a mammal, including man. The invention is also concerned with particles of a viscoelastic medium, production thereof, and use thereof in an implant.BACKGROUND TO THE INVENTION[0003]An implant material that is useful for soft-tissue augmentation should ideal...

AI Technical Summary

Benefits of technology

[0039]Administration of the implant employing the method according to the invention prevents or diminishes migration and / or displacement of the implant, which comprises or consists of the 1-5 mm large particles under physiological conditions. A further advantage of the invention is that the large size of the particles in combination with the prevented or diminished migration facilitate easy removal of the implant comprising the particles, should it be desired for some reason.

[0040]In a preferred embodiment of the invention, the particles have a size in the range of from 1 to 2.5 mm, such as from 1.5 to 2 mm, in the presence of a physiological salt solution. These particles are suitable for administration to subcutaneous, submuscular or supraperiostal tissue. In particular, they are suitable for administration to tissues covered by skin that is exposed in public, such as facial tissue, since the particles and needles that are suitable for this particle size range are not likely to cause bruises or other discolorations. In a preferred embodiment, these particles are administered to deep subcutaneous or to submuscular / supraperiostal tissue, optionally in more than one layer. Deep subcutaneous or submuscular / supraperiostal administration further prevents or diminishes migration of the particles away from the desired site. According to this embodiment, a major volume, or more than 50% (v / v), preferably more than 70% (v / v), more preferably more than 90% (v / v), of the particles are within the given size limits under physiological conditions.

[0041]In another embodiment of the invention, the particles have a size in the range of from 2.5 to 5 mm, such as from 3 to 4 mm, in the presence of a physiological salt solution. Implants comprising such particles further prevents or diminishes migration of the particles away from the desired site. According to this embodiment, a major volume, or more than 50% (v / v), preferably more than 70% (v / v), more preferably more than 90% (v / v), of the particles are within the given size limits under physiological conditions.

[0042]Particle size may be determined in any suitable way, such as by laser diffraction, microscopy, filtration, etc, and is decided by the longest distance between two ends of the particle. The specific shape of the gel particles is not critical. For spherical particles, the diameter equals the size for this purpose. The size range may be regulated by mechanical disruption, such as mincing, mashing, filtration, etc, of a gel of a suitable concentration of the desired viscoelastic medium.

[0043]Viscoelastic media according to the invention include, without being limited thereto, polysaccharides and derivatives thereof. Suitable viscoelastic media include stabilized starch and derivatives thereof. Suitable viscoelastic media can also be selected from stabilized glycosaminoglycans and derivatives thereof, such as stabilized hyaluronic acid, stabilized chondroitin sulfate, stabilized heparin, and derivatives thereof. Suitable viscoelastic media also include stabilized dextran and derivatives thereof, such as dextranomer. The viscoelastic medium may also be a combination of two or more suitable viscoelastic media.

[0044]By the term “stabilized”, as used herein, is meant any form of chemical stabilization that, under physiological conditions, renders the stabilized compound more stable to biodegradation that the parent compound. Without being limited thereto, stabilized compounds include cross-linked compounds and partially cross-linked compounds.

Problems solved by technology

Some known soft-tissue augmentation treatments involving implantation of viscoelastic materials occasionally suffer from the drawback that the implant, or part thereof, migrates away from the desired site of treatment.

Another problem with some known tissue augmentation treatments involving implantation of viscoelastic materials is that the implant is displaced from the desired site of treatment.

Implant migration and displacement are disadvantageous for the patient, since they may impair the cosmetic and / or therapeutic outcome of the treatment and may impede removal of the implant, if this is desired.