APPLICATIONS AND ADVANCEMENTS IN BIOMECHANICAL ENGINEERING A sub-field of Bio-medical Engineering Riyad Mohammed

The Discipline of Biomechanical Engineering  Officially defined as the “…application of mechanical engineering principles, and the use of new materials to biology, especially to surgery and prosthetics.”

The Components of Biomechanical Engineering  Consists of applying concepts of mechanical engineering to the medical field, such as: - Thermodynamics - the study of energy conversion between heat and mechanical work - Fluid Mechanics - the study of how fluids move and the forces which act on them - Solid mechanics - the behavior of solid matter under external actions.

Applications  The application of mechanics to biological systems has allowed society to produce breakthroughs in areas such as: - Artificial organs and human limb prostheses - Medical instrumentation - Biomaterials - Cellular mechanics and Tissue Engineering

Advancements (the interesting part) 1. Surgical Implants  Surgical Implants: devices which are manufactured in order to replace, support, or improve an existing biological structure.  (Im)plants are man-made, whereas a (trans)plant is more likely to be made up of human or animal tissue.  Surgical implants which will contact tissue consists of materials guaranteed to not cause rejection or infection in the body, such as: - Titanium - Silicone - Apatite (a major component of tooth enamel and bone mineral)

2. Artificial “Organs”  The application of Mechanical Engineering to human biology has resulted in the creation of revolutionary devices, which mimic the functions of a human organ.  Types include, but are not limited to: Artificial hearts and pacemakers, artificial lungs, and dialysis machines for the filtration functions of the human kidney. Cochlear implants are used to treat those with There are even Brain pacemakers which use electrical signals to treat people who suffer from epilepsy, Parkinson's disease, major depression and other diseases.

The Artificial Heart  Two successful manufacturers: - 1. Syncardia ™ (formerly Jarvik ™ ) temporary CardioWest Total Artificial Heart ® : - Used as a bridge between hearts for patients on organ waiting lists. - more than 800 implants - 79% of patients survived to transplant - sports the highest bridge-to-transplant rate for any heart device in the world

The Artificial Heart - 2. AbioCor ® replacement heart: - the Massachusetts based company AbioMed ™ has produced the AbioCor ® artificial heart. - It is fully implantable within a patient, meaning that no wires or tubes penetrate the skin, thus reducing the risk of infection. - used in patients with severe end- stage heart disease, who have become ineligible for heart transplant and have no other treatment options. - To date, 15 patients have been implanted with the AbioCor, with one patient living for 512 days with the AbioCor.

The AbioCor artificial heart: How does it work?  External battery - This battery is worn on a Velcro-belt pack around the patient's waist. Each rechargeable battery offers about four to five hours of power.

The AbioCor artificial heart: How does it work?  Wireless energy-transfer system - Officially called the Transcutaneous Energy Transfer (TET), this system consists of two coils, one internal and one external, which transmit power via magnetic force from an external battery across the skin. The internal coil receives the power transmitted from the external coil and sends it to the internal battery and controller device.

The AbioCor artificial heart: How does it work?  Internal battery - A rechargeable battery is implanted inside the patient's abdomen. This gives a patient 30 to 40 minutes to perform certain activities, such as showering, while disconnected from the main battery pack.

The AbioCor artificial heart: How does it work?  Internal Controller - This small electronic device is implanted in the patient's abdominal wall. It monitors and controls the pumping speed of the heart.

The AbioCor artificial heart: How does it work?  The AbioCor heart, also referred to as the Thoracic Unit, connects to four locations: - Right atrium - Left atrium - Aorta - Pulmonary artery  The entire system weighs about 2 pounds (0.9 kg and is composed of titanium and plastic.

The AbioCor artificial heart: How does it work?  Hydraulic pump - A gear inside the pump spins at 10,000 revolutions per minute (rpm) to create pressure.  Porting valve - This valve opens and closes to let hydraulic fluid flow from one side of the artificial heart to the other. When the fluid moves to the right, blood gets pumped to the lungs through an artificial ventricle. When the fluid moves to the left, blood gets pumped to the rest of the body.

2. Artificial “Organs” (Continued) = The artificial Lung  Currently in the last stages of development, the MC3 Company has introduced the BioLung®.  The BioLung® is designed to “replace the gas exchange function of a person’s native lungs during recovery from injury or illness, or until donor lungs are available for transplantation.”  Expected to be marketed commercially through various biomedical firms, including the partially MC3-owned Novalung, a German company dedicated to providing devices to treat lung failure.

The Cochlear Implant  Frequently called the “bionic ear”, a cochlear implant is a surgically implanted electronic device that provides sound to a person who is profoundly deaf or severely hard of hearing.

The Cochlear Implant - Components  i) a microphone which picks up sound from the environment  ii) a speech processor which filters sound to pick up audible speech.

The Cochlear Implant - Components  iii) A transmitter, which is held in position by a magnet placed behind the external ear. Electrical sound signals are sent through a thin cable to the transmitter, and the processed sound signals to:  iv) A receiver and stimulator, which are secured in bone beneath the skin. This converts the signals into electric impulses and sends them through an internal cable to:  v) Electrodes wound inside the cochlea, which send the impulses through the auditory nerve system to the brain stem.

The End Results  The development of the artificial heart has allowed many critical patients to survive during the waiting period of an organ transplant.  Surgical Implants have allowed those crippled by injury or suffering from degenerative diseases to be able to return to their everyday lives.  In the most recent worldwide census, approximately 188,000 people worldwide had received cochlear implants so far. This means that 188,000 people considered permanently deaf have been given the ability to hear sound.  The applications and advancements made through biomechanical engineering have given countless human beings not only relief from illness and discomfort, but also a second chance at life.

Sources  "NEJM -- Cardiac Replacement with a Total Artificial Heart as a Bridge to Transplantation." The New England Journal of Medicine: Research & Review Articles on Diseases & Clinical Practice. Web. 24 Feb  MSN Encarta Online Dictionary. Encarta, Web. 22 Feb  "Biomaterial." Wikipedia, the Free Encyclopedia. Web. 22 Feb  "Artificial Lung (Biolung®)." Medical Device Design and Development — MC3. Web. 22 Feb  "HeartReplacement.com: Abiocore." HeartReplacement.com: Index. Web. 22 Feb