Surgery – Instruments – Electrical application
Reexamination Certificate
2001-02-05
2003-04-08
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C606S045000, C606S046000, C606S048000, C606S050000, C607S099000, C607S105000, C607S113000, C604S114000, C128S898000
Reexamination Certificate
active
06544261
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of electrosurgery, and more particularly to surgical devices and methods which employ high frequency electrical energy to treat tissue in regions of the head and neck, such as the ear, nose and throat. The present invention is particularly suited for treating obstructive sleep disorders, such as sleep-apnea, snoring and the like.
Sleep-apnea syndrome is a medical condition characterized by daytime hypersomnolence, intellectual deterioration, cardiac arrhythmias, snoring and thrashing during sleep. This syndrome is typically divided into two types. One type, termed “central sleep apnea syndrome”, is characterized by repeated loss of respiratory effort. The second type, termed obstructive sleep apnea syndrome, is characterized by repeated apneic episodes during sleep resulting from obstruction of the patient's upper airway.
Treatment for sleep apnea has included various medical, surgical and physical measures. Medical measures include the use of medications and the avoidance of central nervous system depressants, such as sedatives or alcohol. These measures are sometimes helpful, but rarely completely effective. Physical measures have included weight loss, opening nasopharygeal airways, nasal CPAP and various tongue retaining devices used nocturnally. These measures are cumbersome, uncomfortable and difficult to use for prolonged periods of time. In particular, CPAP devices, which act essentially as a pneumatic “splint” to the airway to alleviate the obstruction, must be used for the entire patient's lifetime, and typically requires close to 100% usage of the device while sleeping and napping. These factors result in limited patient compliance with CPAP devices, reducing the effectiveness of the therapy.
Surgical interventions have included uvulopalatopharyngoplasty (UPPP), laser-assisted uvuloplasty procedures (LAUP), tonsillectomy, surgery to correct severe retrognathia and tracheostomy. The LAUP procedures involve the use a CO
2
laser to excise and vaporize excess tissue in the region of the palate and uvula. In UPPP procedures, a scalpel or conventional electrocautery device is typically employed to remove portions of the uvula, palate, pharynx and/or tonsils. While these procedures are effective, the risk of surgery in some patients is often prohibitive. In addition, UPPP and LAUP procedures performed with conventional electrocautery or laser devices typically generate extreme post-operative pain which may be unacceptable to the patient.
Recently, RF energy has been used to selectively destroy portions of the tongue and soft palate to treat air passage disorders, such as sleep apnea. This procedure, which was developed by Somnus Medical Technologies of Sunnyvale, Calif., involves the use of a monopolar electrode that directs RF current into the target tissue to desiccate or destroy submucosal tissue in the patient's mouth. Of course, such monopolar devices suffer from the disadvantage that the electric current will flow through undefined paths in the patient's body, thereby increasing the risk of unwanted electrical stimulation to portions of the patient's body. In addition, since the defined path through the patient's body has a relatively high impedance (because of the large distance or resistivity of the patient's body), large voltage differences must typically be applied between the return and active electrodes in order to generate a current suitable for ablation or cutting of the target tissue. This current, however, may inadvertently flow along body paths having less impedance than the defined electrical path, which will substantially increase the current flowing through these paths, possibly causing damage to or destroying surrounding tissue or neighboring peripheral nerves.
Another disadvantage of conventional RF devices, such as the Somnus monopolar electrode, is that these devices typically operate by creating a voltage difference between the active electrode and the target tissue, causing an electrical arc to form across the physical gap between the electrode and tissue. At the point of contact of the electric arcs with tissue, rapid tissue heating occurs due to high current density between the electrode and tissue. This high current density causes cellular fluids to rapidly vaporize into steam, thereby producing a “cutting effect” along the pathway of localized tissue heating. Thus, the tissue is parted along the pathway of evaporated cellular fluid, inducing undesirable collateral tissue damage in regions surrounding the target tissue site. This collateral tissue damage often causes indiscriminate destruction of tissue, resulting in the loss of the proper function of the tissue. In addition, the device does not remove any tissue directly, but rather depends on destroying a zone of tissue and allowing the body to eventually remove the destroyed tissue.
Yet another disadvantage with the Somnus technology is that the procedure typically takes a long time, often requiring the electrical energy to be applied to the submucosal tissue for a period of longer than a minute. This can be quite uncomfortable to the patient, who is typically awake during the procedure.
SUMMARY OF THE INVENTION
The present invention provides systems, apparatus and methods for selectively applying electrical energy to structures in the head and neck of a patient's body, such as tissue within the ear, nose and throat. The systems and methods of the present invention are particularly useful for treating obstructive sleep disorders, such as snoring or sleep apnea. The present invention includes a channeling technique in which small holes or channels are formed within tissue structures in the mouth, such as the tonsils, tongue, palate and uvula, and thermal energy is applied to the tissue surface immediately surrounding these holes or channels to cause thermal damage to the tissue surface, thereby stiffening the surrounding tissue structure. Applicant has discovered that such stiffening of certain tissue structures in the mouth and throat helps to prevent the tissue structure from obstructing the patient's upper airway during sleep.
Methods of the present invention include introducing one or more active electrode(s) into the patient's mouth, and positioning the active electrode(s) adjacent the target tissue, e.g., selected portions of the tongue, tonsils, soft palate tissues (e.g., the uvula and pharynx), hard tissue or other mucosal tissue. High frequency voltage is applied between the active electrode(s) and one or more return electrode(s) to volumetrically remove or ablate at least a portion of the target tissue, and the active electrode(s) are advanced through the space left by the ablated tissue to form a channel, hole, divot or other space in the target tissue. The active electrode(s) are then removed from the channel, and other channels or holes may be formed at suitable locations in the patient's mouth or throat. In preferred embodiments, high frequency voltage is applied to the active electrode(s) as they are removed from the hole or channel. The high frequency voltage is below the threshold for ablation of tissue to effect hemostasis of severed blood vessels within the tissue surface surrounding the hole. In addition, the high frequency voltage effects a controlled depth of thermal heating of the tissue surrounding the hole to thermally damage at least the surface of this tissue without destroying or otherwise debulking the underlying tissue. This thermal damage stiffens the tissue structure, thereby reducing obstructions to the patient's air passages.
In a specific configuration, electrically conductive media, such as isotonic saline or an electrically conductive gel, is delivered to the target site within the mouth to substantially surround the active electrode(s) with the media. The media may be delivered through an instrument to the specific target site, or the entire target region may be filled with conductive media such that the electrode t
Eggers Philip E.
Ellsberry Maria B.
Hovda David C.
Thapliyal Hira V.
Woloszko Jean
ArthroCare Corporation
Bagade Sanjay S.
Cohen Lee
Raffle John T.
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