The paranasal sinuses are cavities formed within the bones of the face. The paranasal sinuses include frontal sinuses, ethmoid sinuses, sphenoid sinuses and maxillary sinuses. The paranasal sinuses are lined with mucous-producing epithelial tissue. Normally, mucous produced by the linings of the paranasal sinuses slowly drains out of each sinus through an opening known as an ostium, and into the nasopharnyx. Disorders that interfere with drainage of mucous (e.g., occlusion of the sinus ostia) can result in a reduced ability of the paranasal sinuses to function normally. This results in mucosal congestion within the paranasal sinuses. Such mucosal congestion of the sinuses can cause damage to the epithelium that lines the sinus with subsequent decreased oxygen tension and microbial growth (e.g., a sinus infection).
The nasal turbinates are three (or sometimes four) bony processes that extend inwardly from the lateral walls of the nasal cavity and are covered with mucosal tissue. These turbinates serve to increase the interior surface area of the nose and to impart warmth and moisture to air that is inhaled through the nose. The mucosal tissue that covers the turbinates is capable of becoming engorged with blood and swelling or becoming substantially devoid of blood and shrinking, in response to changes in physiologic or environmental conditions. The curved edge of each turbinate defines a passageway known as a meatus. For example, the inferior meatus is a passageway that passes beneath the inferior turbinate. Ducts, known as the nasolacrimal ducts, drain tears from the eyes into the nose through openings located within the inferior meatus. The middle meatus is a passageway that extends inferior to the middle turbinate. The middle meatus contains the semilunar hiatus, with openings or ostia leading into the maxillary, frontal, and anterior ethmoid sinuses. The superior meatus is located between the superior and medial turbinates.
Nasal polyps are benign masses that grow from the lining of the nose or paranasal sinuses. Nasal polyps often result from chronic allergic rhinitis or other chronic inflammation of the nasal mucosa. Nasal polyps are also common in children who suffer from cystic fibrosis. In cases where nasal polyps develop to a point where they obstruct normal drainage from the paranasal sinuses, they can cause sinusitis.
The term “sinusitis” refers generally to any inflammation or infection of the paranasal sinuses. Sinusitis can be caused by bacteria, viruses, fungi (molds), allergies or combinations thereof.
Various drugs have been used to treat sinusitis, including systemic antibiotics. Intranasal corticosteroid sprays and intranasal decongestant sprays and drops have also been used. However, the use of intranasal sprays and drops by most patients does not result in the drug actually entering the affected intranasal sinuses. Rather, such sprays and drops typically contact only tissues located within the nasal cavity. The introduction of drugs directly into the sinuses has been proposed by others, but has not become a widely used treatment technique. For example, United States Patent Application Publication 2004/0116958A1 (Gopferich et al.) describes a tubular sheath or “spacer” formed of biodegradable or non-biodegradable polymer that, prior to insertion in the patient's body, is loaded with a controlled amount of an active substance, such as a corticosteroid or anti-proliferative agent. Surgery is performed to create a fenestration in a frontal sinus and the sheath is inserted into such fenestration. Thereafter, the sheath which has been preloaded with the active substance is inserted into the surgically created fenestration where it a) deters closure of the surgically created fenestration, b) serves as a conduit to facilitate drainage from the sinus and d) delivers the active substance. The sheath of United States Patent Application Publication 2004/0116958A1 (Gopferich et al.) remains substantially in a single configuration (i.e., it does not transition between a collapsed configuration and an expanded configuration) although it may be coated with a material that swells when in contact with mucous or body fluid. In some embodiments, the sheath is formed of multiple layers of polymeric material, one or more of which is/are loaded with the active substance and one or more of which is/are free of the active substance. In other embodiments, the sheath has a “hollow body” which forms a reservoir system wherein the active substance is contained and a membrane which controls the release of the active substance from the reservoir. In some embodiments, the sheath may be anchored by causing the end of the sheath that extends into the sinus to swell or otherwise enlarge.
Also, Min, Yang-Gi, et al., Mucociliary Activity and Histopathology of Sinus Mucosa in Experimental Maxilary Sinusitis: A Comparison of Systemic Administration of Antibiotic and Antibiotic Delivery by Polylactic Acid Polymer, Laryngoscope, 105:835-842 (August 1995) describes experiments wherein experimental sinusitis was induced in three groups of rabbits by “pasting” the natural sinus ostia, forming an incision and small bore hole made in the anterior wall of the sinus, introducing pathogenic microbes through the bore hole and then closing the incision. Five days after introduction of the pathogenic microbes, the natural sinus ostia were reopened and the rabbits were divided into three (3) groups. Group 1 (control) received no treatment. Group 2 received repeated intramuscular injections of ampicillin. In the animals of Group 3, 1.5 cm×1.5 cm sheets of polylactic acid polymer (PLA) film containing ampicillin (0.326 mg/sheet) were rolled up and inserted through the natural ostia into the infected sinuses. Thereafter, measurements of mucocilliary transport speed were made and the tissues lining the affected sinuses were examined histopathologically. The authors concluded that the therapeutic effect observed in the animals that had received intrasinus implants of PLA/Ampicillin film (Group 3) was significantly better that that observed in the untreated control animals (Group 1) or those that has received repeated intramuscular doses of ampicillin (Group 2).
U.S. Pat. No. 3,948,254 (Zaffaroni) describes implantable drug delivery devices comprising a drug reservoir surrounded by a microporous wall. The reservoir may be formed of a solid drug carrier that is permeable to passage of the drug. The rate of passage of the drug through the wall may be slower than the rate at which the drug passes through the solid drug carrier that forms the reservoir. U.S. Pat. No. 3,948,254 (Zaffaroni) describes a number of applications for the implantable drug delivery devices including placement in a nasal passage. Specifically, U.S. Pat. No. 3,948,254 (Zaffaroni) claimed a nasal delivery device for dispensing a drug within a nasal passage at a controlled rate wherein the nasal device is comprised of (a) a wall defining the device dimensioned for insertion and placement within a nasal passage, with the wall formed of a nasal acceptable microporous material, (b) a reservoir surrounded by the wall and comprised of a solid carrier permeable to drug and containing drug in an amount sufficient for the device to meter it at a continuous and controlled rate for a prolonged period of time from the device, (c) a liquid medium permeable to the passage of drug by diffusion charged in the micropores, and (d) wherein the device releases drug when in a nasal environment by passage of drug from the carrier and through the liquid to the exterior of the device to produce a useful result. The entire disclosure of U.S. Pat. No. 3,948,254 (Zaffaroni) is expressly incorporated herein by reference.
Other publications have also reported that introduction of drugs directly into the paranasal sinuses is effective in the treatment of sinusitis. See, Tarasov, D. I., et al., Application of Drugs Based on Polymers in the Treatment of Acute and Chronic Maxillary Sinusitis, Vestn Otorinolaringol. Vol. 6, Pages 45-7 (1978). Also, R. Deutschmann, et al., A Contribution to the Topical Treatment of [Maxillary] Sinusitis Preliminary Communication, Stomat. DDR 26 (1976), 585-592 describes the placement of a resorbable drug delivery depot within the maxillary sinus for the purposes of eluting drugs, specifically Chloramphenicol. In this clinical series a water soluble gelatin was used as carrier and was mixed with the drug prior to application and introduced as a mass into the sinus. Since the substance had little mechanical integrity and dissolved in a relatively short timeframe, to achieve a therapeutic effect, the author suggested that it must be instilled every 2 to 3 days. An alternative to gelatin could be a sponge loaded with the therapeutic substance as suggested in U.S. Pat. No. 6,398,758 (Jacobsen, et al.). In this patent directed at delivering a sustained release device against the wall of a blood vessel, a hollow cylindrical sponge is loaded with drug and pressed against the wall. This allows the drug to contact the wall while sustaining blood flow within the center of the lumen. Further, a skin is provided to direct the drug into the walls of the blood vessel and prevent drug from flowing into the lumen. While sponges loaded with drug at the time of their application do permit some degree of sustained release, the time required to load them also correlates closely the time over which they will elute substance. Thus, if delivery is required for a longer period of time additional mechanisms must be employed to regulate their release.
There are also several examples in the patent literature where various sustained release mechanisms have generally been proposed using systems with pre-incorporated drugs into matrices or polymers. These include U.S. Pat. No. 3,948,254 (Zafferoni), US 2003/0185872A2 (Kochinke), WO 92/15286 (Shikani), and U.S. Pat. No. 5,512,055 (Domb, et al.). In general, these references discuss various materials and structures that may be used to construct sustained drug delivery vehicles and provide a good overview of the state of sustained drug delivery art. While helpful in laying out certain materials and schemes for creating sustained release systems for drugs, each of these references, however, do not describe specific methods, means or structures which would permit them to be easily adapted for intended uses in the targeted in this application.
Another common ear, nose and throat disorder is otitis media or inflammation of the middle ear. Most cases of otitis media are associated with some degree of Eustachian tube disfunction. Because air cannot adequately pass through the Eustachian tube into the middle ear, negative pressure can be created within the middle ear. This negative pressure may essentially pull or draw fluid out of the lining of the middle ear/mastoid, thereby resulting in an accumulation of fluid in the middle ear behind the eardrum. In some cases, fluid that accumulates within the middle ear can become infected. Several types of otitis have been identified. Serous otitis typically results from a fairly sudden obstruction of the Eustachian tube and is characterized by the collection of generally thin, clear fluid in the middle ear and mastoid. If this fluid does not clear within a few weeks, it is considered chronic serous otitis. Secretory otitis typically occurs in small children and is characterized by the collection of a thick fluid in the middle ear and mastoid. This thick fluid contains muccoid material that has been secreted by the mucous glands of the middle ear and also contains enzymes that can damage the small bones and other tissues of the middle ear. If left untreated, these enzymes can erode the bones enough to cause permanent hearing loss. Acute otitis media is characterized by the accumulation of pus in the middle ear and typically occurs in patients who have active respiratory infections which result in an abrupt obstruction of the Eustachian tube at the same time as infectious bacteria are present. Without antibiotic treatment, acute otitis of bacterial origin can cause perforation of the eardrum, with drainage of pus from the ear. Although the eardrum may heal after the infection has resolved, permanent damage to the middle ear and/or the inner ear can sometimes result from infections of this severity. Chronic otitis media is typically caused by a form of chronic mastoiditis and results in a chronic infection of the middle ear and mastoid cavity. Because the mastoid bone is involved, treatment with antibiotics administered by traditional routes of administration (i.v., i.m., oral, etc.) sometimes does not remove the infection from the bone and surgical removal of the infected mastoid bone may be necessary. A common complication associated with chronic otitis and mastoiditis is cholesteatoma. A cholesteatoma is a soft tissue sac that emanates from the eardrum and grows back into the middle ear or mastoid, thereby creating a mass of progressively increasing size which can destroy or damage the bones of the middle ear, the inner ear, the facial nerve and/or portions of the brain. Thus, the various forms of otits can be very serious if left untreated.
There remains a need in the art for the development of new devices and methods for delivering drugs and other therapeutic or diagnostic substances into paranasal sinuses, Eustachian tubes, middle ear and/or other locations within the body for the treatment of sinusitis, otitis or other diseases and disorders.