Surgery – Instruments – Electrical application
Reexamination Certificate
2000-06-01
2002-11-12
Peffley, Michael (Department: 3739)
Surgery
Instruments
Electrical application
C606S041000, C606S046000, C606S049000, C607S099000, C128S898000
Reexamination Certificate
active
06478793
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the advances in medical systems and procedures for prolonging or improving human life. More particularly, this invention relates to an improved method and system for destroying cancerous bone metastatic tumors and relieving pain symptoms caused by such tumors or metastatic disease.
BACKGROUND OF THE INVENTION
A very large percentage of all cancerous disease which spreads, or metastasizes, results in growth of metastatic tumors, called meta stases, in the bony structures of the patient's body. In advanced metasta tic bone disease, the patient experiences excruciating pain due to pressure of the tumor on surrounding nerves, tissue, and the innervation of the bone and endosteum or periosteum itself. The quality of the patient's life at this point can deteriorate quickly, and the levels of pain become intolerable.
The common methods of treating metasta tic cancerous tumors include radiation therapy. Application of X-ray radiation therapy can slow the progression of bone metasta tic cancer growth but usually cannot halt it. Moreover, some bone metastases are relatively unresponsive to radiation therapy. Another problem with radiation therapy is that it causes death of the bone marrow which produces the red blood cells that are vital to life. Therefore, only a limited amount of X-ray dosage can be given before critical destruction of bone marrow takes place. Another limitation of radiation therapy is that once it has been administered up to a certain dose level, further application of the radiation therapy typically is prohibited. This is to prevent overdosing of the surrounding normal tissue and organs in the patient. In sum, radiation therapy has a limited repeatability.
Radiation therapy also is a relatively complex and expensive procedure. Localization of the cancerous tumor with respect to the therapeutic X-ray beam may be difficult as a result of inaccurate patient positioning on an X-ray delivery device such as a linear accelerator (LINAC). To be effective, fractionated or repeated doses of radiation have to be given over a period of weeks or months. This is expensive in terms of equipment time and personnel costs, and can be inconvenient for a patient who is ill.
Localization of the metastatic tumor volume in the X-ray beam is a difficult technical problem which remains a challenge for radiation therapy. As a consequence of the indefiniteness of the tumor localization in the X-ray beam, larger margins of dosimetry must be given. This further puts at risk sensitive, normal tissue or organs that are nearby the bone and the bone tumor. Excess delivery of radiation to normal tissue can be very harmful with severe side effects and deterioration of the patient's condition and quality of life.
Chemotherapy is another method of treating bone metastases. This is a systemic treatment that can cause severe sickness in and inconvenience to the patient. Because of the toxicity of chemotherapy, the rest of the body's systems are put at risk. Moreover, the effectiveness of chemotherapy in targeting the bone tumor itself is limited.
The treatment of a primary benign bone tumor using a percutaneously placed radiofrequency electrode has been reported by Rosenthal, et al. in their paper entitled “Percutaneous Radiofrequency Treatment of Osteoid Osteomas,” Seminars in Masculoskeletal Radiology, Volume 1, Nov. 2, 1997. A radiofrequency electrode was inserted into the small primary bone tumor and connected to a radiofrequency power source to heat the bone tumor so as to destroy it. A bone tumor which they destroyed was of a type called “osteo-osteoma,” which is a relatively rare disease. They were successful in heating the osteo-osteoma tumor and destroying it completely in some cases. Osteo-osteomas are typically small tumors with a diameter of 1 to 2 centimeters. Rosenthal did not contemplate treating larger bone cancer or the painful condition they create.
It should be recognized that the theory behind and practice of radiofrequency (RF) heat lesioning has been known for decades, and a wide range of RF generators and electrodes for accomplishing such practice exist. For example, equipment for performing heat lesions is available from Radionics, Inc., located in Burlington, Massachusetts. Radiofrequency (RF) ablation is well known and is described in medical and clinical literature. To that end, a research paper by E. R. Cosman, et al., entitled “Theoretical Aspects of Radiofrequency Lesions in the Dorsal Root Entry Zone,”
Neurosurgery
, Vol. 15; No. 6, pp. 945-950 (1984), describing various techniques associated with radiofrequency lesions, is incorporated herein by reference. Also, by reference, a research paper by S. N. Goldberg, et al., entitled “Tissue Ablation with Radiofrequency: Effective Probe Size, Gauge, Duration, and Temperature on Lesion Volume,”
Acad. Radiol
., Vol. 2; pp. 399-404 (1995), describes techniques and considerations relating to tissue ablation with radiofrequency energy.
In addition, a paper by S. N. Goldberg, et al., entitled “Hepatic Metastases: Percutaneous Radiofrequency Ablation with Cool-Tip Electrodes,”
Radiology
, Vol. 205, No. 2, pp. 367-373 (1997), describes various techniques and considerations relating to tissue ablation with radiofrequency electrodes having cooled electrode tips. Cooling of the electrode can result in larger volume of RF heating due to the extension of the heating volume to greater radii away from the electrode. Cooled ablation electrodes may maintain tissue near the electrode at temperatures that are below tissue ablation temperatures.
SUMMARY OF THE INVENTION
A technique which is minimally invasive, safe, and effective for ablating large metastatic bone tumors for the purpose of destroying the tumor and for the purpose of relieving pain associated with such metastases is desirable. Accordingly, an effective technique for performing RF electrode ablation of metastatic tumors is desirable for the purpose of reducing the volume of the metastatic tumor, for killing the entire tumor volume, or at least a portion of the tumor volume, and for the alleviation of pain for the patient.
The present invention is directed towards a system and procedure for heat ablation of bone metastases through use of a probe which is advanced either percutaneously or under direct surgical approach into the bone metastasis or into peri-osseous tissue (tissue on, near, surrounding, or in the bone). The guidance of the probe into the bone metastasis can be assisted by various imaging methods such as ultrasound, CT, MRI, stereotactic, or other imaging or image-guided system methodologies. The advantages of the present system and method reside in their combined simplicity, economy, control, consistency, enablement of good ablation position and shape, total destruction of metastatic tumor and clinical effectiveness to reduce the tumor volume. Another advantage of the present system and method is that in some cases it can provide instant pain relief for the patient who suffers from the advancement of metastatic bone tumors.
In one embodiment, the technique of the present invention involves inserting a rigid, tissue-piercing radiofrequency (RF) electrode through the patient's skin into the region of the tumor, as visualized under a CT tomographic scan. The RF electrode can be of a cooled type, as described by Goldberg, et al. in the reference above. Application of sufficient power from an RF generator connected to the electrode will deliver heat to the metastatic tumor, thereby destroying part or all of the tumor volume by reducing the tumor to a necrotic fluid mass which may be absorbed by the patient's body. The use of multiple and/or curved electrodes placed into the tumor volume can supplement the shaping of the RF ablation heat region. This application of an RF heating electrode or other type of thermal probe or pulsed RF element into the tumor, surrounding bone, or peri-osseous tissue can also relieve pain in accordance with the present invention.
In contrast to radiation th
Cosman Eric R.
Rittman William
Peffley Michael
Ruddy David M.
Sherwood Services AG
LandOfFree
Ablation treatment of bone metastases does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ablation treatment of bone metastases, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ablation treatment of bone metastases will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2988165