Resorbable hollow devices for implantation and delivery of therapeutic agents

Abstract

A method of manufacturing a resorbable balloon designed to contain bone cement for vertebroplasty or kyphoplasty applications is described. The resorbable balloon can be inserted into a vertebral body following vertebral cavitation and filled with bone cement. The balloon remains in place in the vertebral body and resorbs over time. Methods and apparatus are also described for delivering therapeutic agents using collapsible, resorbable balloons. The balloons may be nested and filled with various therapeutic agents that are released over time at rates dependent upon structures and degradation rates of the balloons. Furthermore, the function of the hollow devices can encompass both encapsulation and therapeutic substance delivery roles simultaneously.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 653,778, filed Feb. 16, 2005 and entitled RESORBABLE BALLOON FOR BIOMEDICAL IMPLANTATION, and U.S. Provisional Application No. 60 / 672,839, filed Apr. 18, 2005 and entitled RESORBABLE HOLLOW DEVICES FOR DELIVERY OF THERAPEUTIC AGENTS, the entire contents of both which are hereby incorporated by reference. This application also relates to U.S. application Ser. No. 10 / 129,214 (Docket MA9263P), filed Oct. 21, 2002 and entitled TIME-RELEASED SUBSTANCE DELIVERY DEVICE, the entire contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to implants and, more particularly, to biomedical balloons and applications employing such balloons. [0004] 2. Description of Related Art [0005] Balloon catheters have been employed in angioplasty applications for many years. A cathe...

AI Technical Summary

Benefits of technology

[0012] The present invention provides a resorbable (e.g., bioresorbable, degradable, biodegradable, absorbable, bioabsorbable, erodible, bioerodible) balloon that can encapsulate cement in vertebroplasty and kyphoplasty applications until the cement has an opportunity to harden, thereby preventing incursion of the cement into soft tissue and nerves in a vicinity of bone being treated. The invention herein disclosed includes a method of forming a resorbable balloon comprising, according to an illustrative implementation, extruding resorbable tubing and cutting the tubing to desired lengths, thereby forming a plurality of tubes. A region of a tube is heated, and the tubing that forms the tube can be pulled along an axis of the tube, thereby thinning a wall of the tube at the heated region. Heated air is forced through a lumen of the tube while heating the region of the tube so that the tubing expands and forms a balloon in the heated region. An end of the tube is sealed by a thermal method or by gluing a resorbable plug into the lumen, and excess tubing beyond the sealed point is removed. According to an illustrative example, the resorbable balloon may be employed in a bone restoration procedure whereby a volume of bone is evacuated to form a cavity in the bone. A deflated resorbable balloon is inserted into the cavity, and the resorbable balloon is filled with bone cement, thereby inflating the balloon and filling the cavity. The resorbable balloon subsequently biodegrades to bring the bone cement into contact with bone within the cavity.

Problems solved by technology

Inflating the balloon may cause pieces of the fracture to return to a positions or orientations approximating those existing before for example a traumatic event that caused the fracture.

Unfortunately, cement extravasation can be a problem in these kyphoplasty and vertebroplasty situations.

For instance, cement inserted into bone may extrude into surrounding tissues and nerves, causing pain and other complications.

Such a solution may not always be viable due for example to confounding factors such as situations wherein the presence of the balloon may prevent bonding between the bone cement and the bone tissue of interest.

Consequently, gaps may form between an outer surface of the balloon and surrounding bone, introducing for example attendant risks of infection, bone loss, and pain.

Systemically delivered medicinal substances can be inefficient when only a small amount of the administered dose reaches the site sought for therapeutic action.

Moreover, with systemic delivery a medicinal substance can enter parts of the body where it can actually do harm or produce a noxious side effect.

In some cases the therapeutic agent is destroyed, denatured, or looses its activity when combined with the delivery vehicle or material.

In other cases, controlled delivery devices rely on diffusion of the therapeutic agent from the delivery material or vehicle, but the therapeutic agent may be too large to diffuse through a delivery material matrix of the controlled delivery device at a reasonable rate.

The microspheres, however, may be difficult to retrieve if there is a complication.

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