Methods for sensing retrograde flows of bone fill material

Abstract

The present invention relates in certain embodiments to medical devices and methods for use in osteoplasty procedures, such as vertebral compression fractures. One method for treating an abnormal vertebra includes flowing a bone fill material through an introducer into a vertebral body along a first direction and sensing a flow of said bone fill material about an outer surface of the introducer in a second direction different from said first direction. In other embodiments, a signal is generated to alert a physician of said bone fill material flow in said second direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60 / 713,521, filed Sep. 1, 2005, U.S. Provisional Patent Application No. 60 / 762,611, filed Jan. 27, 2006, and of U.S. Provisional Application No. 60 / 788,755, filed Apr. 3, 2006, the entire contents of which are hereby incorporated by reference and should be considered a part of this specification.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates in certain embodiments to medical devices for osteoplasty treatment procedures, such as vertebral compression fractures. More particularly, embodiments of the invention relate to methods for sensing retrograde flows of bone fill material injected into bone, such as vertebral bodies. [0004] 2. Description of the Related Art [0005] Osteoporotic fractures are prevalent in the elderly, with an annual estimate of 1.5 million fractures in the United States alone. These include ...

AI Technical Summary

Benefits of technology

[0018] Certain embodiments of the invention provide systems and methods for treating bone, such as a vertebra by delivering bone fill material into the interior of the vertebra. One embodiment utilizes Rf energy or other energy sources to controllably elevate the temperature of bone fill material flows as the flows exit the working end of an introducer. A computer controller controls the bone fill material flow parameters and energy delivery parameters for selectively polymerizing the fill material inflow plume to thereby control the direction of flow and the ultimate geometry of a flowable, in-situ hardenable bone fill material. The system and method further includes means for sealing tissue in the interior of a vertebra to prevent migration of monomers, fat or emboli into the patient's bloodstream.

[0022] In another embodiment, a controller is provided to control all parameters of bone fill material injection. For example, the controller can control bone fill material inflow parameters from, for example, a hydraulic mechanism. The controller can also control the sensing system and energy delivery parameters for selectively heating tissue or polymerizing bone fill material at both the interior and exterior of the introducer. The workload on a physician during an osteoplasty procedure can thus advantageously be reduced.

Problems solved by technology

Medical advances aimed at slowing or arresting bone loss from aging have not provided solutions to this problem.

Osteoporosis affects the entire skeleton but most commonly causes fractures in the spine and hip.

Spinal or vertebral fractures also cause other serious side effects, with patients suffering from loss of height, deformity and persistent pain which can significantly impair mobility and quality of life.

Osteoporosis describes a condition of decreased bone mass that leads to fragile bones which are at an increased risk for fractures.

In an osteoporosis bone, the sponge-like cancellous bone has pores or voids that increase in dimension making the bone very fragile.

In an elderly patient, bone resorption can surpass bone formation thus resulting in deterioration of bone density.

Since the PMMA needs to be is forced into the cancellous bone, the techniques require high pressures and fairly low viscosity cement.

Since the cortical bone of the targeted vertebra may have a recent fracture, there is the potential of PMMA leakage.

Leakage of PMMA during vertebroplasty can result in very serious complications including compression of adjacent structures that necessitate emergency decompressive surgery.

The exothermic reaction of PMMA carries potential catastrophic consequences if thermal damage were to extend to the dural sac, cord, and nerve roots.

Vertebroplasty patients often return with new pain caused by a new vertebral body fracture.

Leakage of cement into an adjacent disc space during vertebroplasty increases the risk of a new fracture of adjacent vertebral bodies.

Another life-threatening complication of vertebroplasty is pulmonary embolism.

The vapors from PMMA preparation and injection also are cause for concern.

In both higher pressure cement injection (vertebroplasty) and balloon-tamped cementing procedures (kyphoplasty), the methods do not provide for well controlled augmentation of vertebral body height.

Thus, the reduction of a vertebral compression fracture is not optimized or controlled in high pressure balloons as forces of balloon expansion occur in multiple directions.

Expansion of the balloon under high pressures close to cortical bone can fracture the cortical bone, typically the endplates, which can cause regional damage to the cortical bone with the risk of cortical bone necrosis.

Such cortical bone damage is highly undesirable as the endplate and adjacent structures provide nutrients for the disc.

Kyphoplasty also does not provide a distraction mechanism capable of 100% vertebral height restoration.

Further, the kyphoplasty balloons under very high pressure typically apply forces to vertebral endplates within a central region of the cortical bone that may be weak, rather than distributing forces over the endplate.

Images