Embed Size (px)
DESCRIPTION
zdxgfgzxdfvcvg sdfxczDXvzzfg
Citation preview
Auricular Prosthesis - Artificial Ear Prosthetic Services
An artificial auricular / ear prosthesis restores a portion or the entire outer ear. The artificial ear,
or auricular prosthesis provides a form of rehabilitation when surgical reconstruction is
not viable or not preferred by the patient.
Artificial ear prostheses can be attached to the patient either via a skin adhesive or osseointegrated craniofacial implants.
The artificial ear prosthetics are made of a medical silicone which is colored to match the natural ear skin tissue.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxA device designed to duplicate the frequency response, acoustic impedance, threshold sensitivity, and relative perception of loudness, consisting of a special microphone enclosed in a box with properties similar to those of the human ear.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
The human ear is acoustically a complicated structure with volumes, channels and damping resulting in complex acoustical impedance. Also, at higher frequencies, the diffraction around the outer ear will change the acoustic field and result in a unique response at the inner ear.
In order to be able to compare and quantify measurements related to the human ear, a number of international standards and recommendations have defined some "ideal" or average ears. These can be simulated by more or less complicated mechanical and acoustical systems.
The so called "IEC 318” coupler is an example of a standardized human ear, having the same acoustic input impedance as an average human ear.
Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Common Approaches to Ear ReconstructionVarious methods to reconstruct ears have been introduced, but none have stood the test of time as well as the sculptured rib graft technique. Natural tissue, such as
sculptured rib, has several advantages over artificial implants, plastic glue-ons, or snap-on ears. First of all, natural tissue is acceptable to the patient under many circumstances where the body would reject an artificial ear. Silastic ear implants are notorious for not only rejections, but also for infections healing problems. In addition, glue-on or snap-on artificial ears can be pulled off. Can you imagine the embarrassment of your child, if the class clown yanked off the ear, holding it up to the classmates? Due to the risk of the ear coming off, sports participation with artificial ears may be limited. Once implanted, a rib graft ear retains some sensation on the skin, whereas a plastic ear has no sensation at all. Natural skin changes color in various situations. While a plastic ear may match the adjacent skin color well most of the time, it does not blush or flush as one’s face normally does when excited, cold, or embarrassed. Nor does an artificial ear suntan. Finally, while a plastic ear color may be matched well for photography, it becomes artificial looking in the real world due to its inability to change color naturally.
For most patients, completing the ear reconstruction takes four stages. These steps are spaced 2-3 months apart to allow for healing. Most patients do not experience any significant ear discomfort with any of the stages. Blood transfusions are not required.
Stage
1
Rib
Graft
Hospital stay—two to three days.
Return Visit—seven days after surgery.
Age for Surgery—5-6 years old optimal, but any age
afterwards.
Head bandages for ten days.
Stage
2
Earlobe
Hospital Stay—outpatient and discharged same day.
Return Visit—stitches removed after one week.
Timing of Surgery—minimum two months after
Stage 1.
Stage
3
Elevatio
n
or
Lifting
Hospital Stay—outpatient and discharged same day.
Return Visit—one week after surgery.
Timing of Surgery—at least three months after
Stage 2 completed.
Stage
4
Tragus
&
Externa
l
Canal
Hospital Stay—outpatient and discharged same day.
Return Visit—one week after surgery.
Timing of Surgery—at least three months after
Stage 3 completed
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxMATERIALS USEDAn artificial middle ear prosthesis may be used to replace the ear structure from the bony ear canal up to the oval window of the vestibule. The artificial middle ear includes a tube to replace at least part of the bony ear canal, an annulus to connect an artificial ear drum to the tube, a complex structure to replace the hammer and anvil of a human patient and a piston means connected to the complex structure to replace at least part of the stirrup. According to one embodiment the piston may directly connect the complex hammer/anvil structure to the remaining portion of the oval window of the vestibule. According to another embodiment, the piston may be terminated in a cup shaped socket which will cradle the remaining structure of a stirrup. The bony ear canal tube, the umbo section connecting the complex hammer/anvil structure to the ear drum and the end of the piston directly contacting the stirrup or the oval window are preferably coated with a microporous biocompatible material such as Proplast. The ring or annulus is preferably formed from polytetrafluorethylene or a perfluorinated ethylene propylene polymer. The invention makes it possible to totally eradicate chronic otitis media without sparing the bony ear canal or bony annulus, by replacing the diseased tissues with the prosthesis described. Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
These artificial prostheses are made of special silicone materials that can be artistically pigmented to resemble natural body parts in colour, texture and feel.
Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Artificial middle ear mucosa (AMEM), a sheet of mucosal cells grown on collagen gel populated with fibroblasts, is useful as graft material that is able to promote mucosal regeneration after middle ear surgery.Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
COMPARISONEars constructed from the patient’s own rib cartilage grow with the children, heal, retain their form indefinitely, and have withstood the test of time. The rough-and-tumble lifestyle of children will not destroy ears constructed from their own living tissue; over the years I have witnessed the survival of cartilage-formed ears from every type of trauma imaginable.[10] The percentage of synthetic frameworks that will last long-term without troubles will only come to light over the ensuing decades.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
In almost all cases, these replacement devices are constructed of natural or synthetic polymeric materials. Such biomaterials must exhibit good compatibility with the blood and the body fluids and tissues with which they come into contact. In addition, the artificial device must closely duplicate the function of the natural organ. In practice, these artificial devices are constructed from a wide variety of materials such as metals, ceramics (including glass and carbon), natural tissues (actually polymeric in nature), and synthetic polymers. Partly due to the wider range of properties available, most of these artificial devices are constructed wholely or partly from natural or synthetic polymers. Obviously the same polymer could not be used for all possible artificial organs or prosthetic devices. Rather, the material to be used must be matched to the specific use
requirements. Artificial organs can conveniently be classed into four groups: (I) Bone/Joint Replacements (e.g. hip, knee, finger, total limb), (II) Skin/Soft Tissue Replacements (e.g. skin, breast, muscle), (III) Internal Organs (e.g. heart, kidney, blood vessels, liver, pancreas), and (IV) Sensory Organs (e.g. eye, ear).
Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Similarly, siliconised rubber is being used as a prosthesis material to give shape to the missing ear cartilage. To give flexibility to the outer ear when natural cartilage has been destroyed and re-moved, rubber is moulded into the ear shape and implanted under the skin after hardening.A biomaterial, Bio-glass, is under development for filling in the space left by missing soft tissue (by splinters or blasts) and to give appropriate fullness and shape, particularly following maxillofacial injury and tissue loss. Bio-glass also helps in rapid healing of the wounds by providing a matrix for expansion of the healing tissue.Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
