These devices, including deep brain stimulators, send electrical impulses to the brain in order to relieve depression, epilepsy, tremors of Parkinson's disease, and other conditions such as increased bladder secretions. Rather than replacing existing neural networks to restore function, these devices often serve by disrupting the output of existing malfunctioning nerve centers to eliminate symptoms.
Artificial cardia
This pertains to gastric repairs, specifically of the valves at either end of the stomach. Artificial cardia can be used to fight, between other diseases, esophageal cancer, achalasia and gastroesophageal reflux disease.
Artificial corpora cavernosa
To treat erectile disfunction, both corpora cavernosa can be irreversibly surgically replaced with manually inflatable penile implants. This is a drastic therapeutic surgery meant only for men suffering from complete impotence that has resisted all other treatment approaches.
An implanted pump in the (groin) or (scrotum) can be manipulated by hand to fill these artificial cylinders, normally sized to be direct replacements for the natural corpus cavernosa, from an implanted reservoir in order to achieve an erection.
Artificial ear
For external cosmetic repair see plastic surgery.
For internal restoration of auditory function see Cochlear implant. While natural hearing, to the level of musical quality, is not typically achieved, most recipients are pleased, with some finding it useful enough to return to their surgeon with a request to do the other ear.
Artificial eye
The most successful function-replacing artificial eye so far is actually an external miniature digital camera with a remote unidirectional electronic interface implanted on the retina, optic nerve, or other related locations inside the brain. The present state of the art yields only very partial functionality, such as recognizing levels of brightness, swatches of color, and/or basic geometric shapes, proving the concept's potential. While the living eye is indeed a camera, it is also much more than that.
As explained in the main article about the retina, various researchers have demonstrated that the retina performs strategic image preprocessing for the brain. The problem of creating a 100% functional artificial electronic eye is even more complex than what is already obvious. Steadily increasing complexity of the artificial connection to the retina, optic nerve or related brain areas advances, combined with ongoing advances in computer science, is expected to dramatically improve the performance of this technology.
For the person whose damaged or diseased living eye retains some function, other options superior to the electronic eye described above may be available, as explained in the main article Visual prosthetic.
None of the current devices presents the cosmetic appearance of a living eye. For the nonfunctional cosmetic artificial eye, generically a "glass" eye, please see instead Ocular prosthetic.
Heart
Artificial heart
While considered a success, the use of artificial hearts is limited to patients awaiting transplants whose death is imminent. The current state of the art devices are unable to reliably sustain life beyond about 18 months.
These electronic devices, which can either intermittently augment (defibrillator mode), continuously augment, or completely bypass the natural living cardiac pacemaker as needed, are so successful that they have become commonplace.
Artificial arms with semi-functional hands, some even fitted with working opposable "thumbs" plus 2 "fingers", and legs with shock absorbing feet capable of allowing a trained patient to even run, have become available. While the meaning of "full mobility" is debated, steady progress is made, as described in the main article Prosthesis.
HepaLife is developing the first-of-its-kind bioartificial liver device intended for the treatment of liver failure using the Company’s patented PICM-19 liver stem cell line. The HepaLife bioartificial liver, currently under development, is designed to serve as a supportive device, either allowing the liver to regenerate upon acute liver failure, or to bridge the patient's liver functions until a transplant is available [1]. It is only made possible by the fact that it uses real liver cells, and even then, it is not a permanent substitute for a liver.
On the other hand, Researchers Dr. Colin McGucklin, Professor of Regenerative Medicine at Newcastle University, and Dr. Nico Forraz, Senior Research Associate and Clinical Sciences Business Manager at Newcastle University, say that pieces of artificial liver could be used to repair livers injured in the next five years. These artificial livers could also be used outside the body in a manner analogous to the dialysis process used to keep alive patients whose kidneys have failed. [2][3]
With some almost fully functional, artificial lungs promise to be a great success in near future.[citation needed]
For the treatment of diabetes, numerous promising techniques are currently being tested, including some that incorporate donated living tissue housed in special materials to prevent the patient's immune system from killing the foreign live components.
This represents a unique success in that these are autologous laboratory-grown living replacements, as opposed to most other artificial organs which depend upon electro-mechanical contrivances, and may or may not incorporate any living tissue.
Artificial ovary
Reproductive age patients who develop cancer often receive chemotherapy or radiation therapy which damages oocytes and leads to early menopause. An artificial human ovary has been developed at Brown University[4] with self-assembled microtissues created using novel 3-D petri dish technology. The artificial ovary will be used for the purpose of in vitro maturation of immature oocytes and the development of a system to study the effect of environmental toxins on folliculogenesis.
Beyond restoration
It is also possible to construct and install an artificial organ to give its possessor abilities which are not naturally occurring. Research is proceeding, particularly in areas of vision, memory, and information processing, however this idea is still in its infancy.
Some current research focuses on restoring inoperative short-term memory in accident victims and lost access to long-term memory in dementia patients. Success here would lead to widespread interest in applications for persons whose memory is considered healthy to dramatically enhance their memory of far beyond what can be achieved with mnemonic techniques. Given that our understanding of how living memory actually works is incomplete, it is unlikely this scenario will become reality in the near future.
One area of success was achieved in 2002 when a British Scientist, Kevin Warwick, had an array of 100 electrodes fired into his nervous system in order to link his nervous system into the internet. With this in place he carried out a series of experiments including extending his nervous system over the internet to control a robotic hand, a form of extended sensory input and the first direct electronic communication between the nervous systems of two humans[5].
Another idea with significant consequences is that of implanting a Language Translator for diplomatic and military applications. While machine translation does exist, it is presently neither good nor small enough to fulfill its promise.
This might also include the existing (and controversial when applied to humans) practice of implanting subcutaneous "chips" (integrated circuits) for identification and location purposes. An example of this is the RFID tags made by VeriChip Corporation.
News stories:
ScienceDaily (Nov. 20, 2009)
Newer Heart Devices, Left Ventricular Assist Device (LVAD), Significantly Improve Survival, Complication Rate and Quality of Life.
A new generation of implanted devices that help a failing heart function properly is significantly more effective than the previous version, making these new devices an appropriate permanent therapy for many of the more than 5 million Americans who suffer from heart failure.
A research team led by a University of Louisville cardiac surgeon published data to support these conclusions in the November 17, 2009 Online First edition of the New England Journal of Medicine. The results were simultaneously presented in a press briefing at the annual meeting of the American Heart Association in Orlando, Fla.
"This study shows astounding improvements in survival, quality of life, reduced complications and device durability in patients who had the new device implanted," said Mark Slaughter, M.D., chief of thoracic and cardiovascular surgery at the University of Louisville and director of the heart transplant and mechanical assist device program at Jewish Hospital, lead enroller in the trial and lead author on the journal article. "This device should be considered for use in all patients who are eligible for this kind of treatment either while they await heart transplant or as a permanent therapy."
Two hundred patients at 38 centers nationwide were randomly assigned to receive either the newer, smaller continuous-flow left ventricular assist device (LVAD), or a larger, pulsatile-flow LVAD. The newer device creates a continuous flow of blood in and out of the failing heart, while the older device mimics the heart's function using a pulse action with blood alternately sucked into the pump from the left ventricle then forced out into the aorta.
Fifty-eight percent of patients implanted with continuous-flow devices were alive two years after implantation, compared to just 24 percent of those with pulsatile flow devices. Nearly half of all patients who received a continuous-flow LVAD did not have a stroke or re-operation to repair or replace the device within two years of implantation, compared to just 11 percent of those with a pulsatile-flow device.
Patients with continuous flow LVADs also were half as likely to get an infection as their pulsatile-flow counterparts.
"We also looked at quality-of-life measures and found that patients with continuous flow LVADs could walk twice as far in six minutes, on average, than those with a pulsatile-flow device," Slaughter said. "Patients with continuous flow devices went from being unable to walk any distance at all without being short of breath to being able to walk the length of three football fields, on average. This is hugely significant for these patients."
This research was supported by Thoratec, the maker of both devices tested and the largest producer of cardiac mechanical assist devices in the United States. The devices are sometimes used while patients are awaiting heart transplants, though there is a demand for them to be used as a stand-alone therapy in certain patients with end-stage heart failure, Slaughter said. One reason for this is the number of patients who are eligible for heart transplantation is vastly larger than the amount of donor hearts available, he said.
LVAD support has been used as a treatment for advanced heart failure since the 1960s, experimentally, but it was not until the early twenty-first century that it became more widely used and began to be considered as a permanent, or destination, therapy. Less than 10 percent of patients with advanced heart failure similar to the patients in this study survive for two years after diagnosis if they only receive medical therapy.
Approximately 5.7 million Americans suffer from heart failure, and 550,000 new cases are diagnosed each year. About 250,000 die from heart failure annually.
Slaughter receives grant support from Thoratec.
