Project 1

1. Describe one common clinical condition or disorder associated with the system selected

Lung Cancer (System involved respiratory system)

Gross Anatomy, Structure and function of Lung

There are two lungs (a right and left) in the body, but they are different sizes. The right lung is bigger and is divided into three lobes (separated by fissures), while the left lobe is smaller consisting of two lobes. The left lobe is also smaller as it has to make room for the heart.

The lungs are a major organ that is part of the respiratory system, taking in fresh air and getting rid of old, stale air. This mechanism of breathing also helps to allow you to talk. By taking in fresh air, the lungs are able to help oxygenate blood to be carried around your body. This is done by inhaling the air and bringing it in toward the pulmonary capillaries, which then become oxygen-filled cells that help with respiration.

Description of the clinical condition - Lung Cancer

Normal function of the organ – To extract oxygen from the air and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange.

Current pathological state – Presence of tumour cells in the lungs

Reason for the pathological condition – Lifestyle changes

Homoeostasis Change - When the cancer cells actively divide, they require more food and oxygen for that, hence they compete actively with the normal cells for food and oxygen , ultimately making them starve to death

Diagnostic methods

Staging of lung cancer: Staging is used to determine the severity of lung cancer so that the appropriate treatment is delivered. Endobronchial ultrasound allows healthcare providers to obtain tissue from within the lung or mediastinal lymph nodes in the chest using a technique called transbronchial needle aspiration. The biopsied cells can then be sent to the lab for analysis to help determine how early or advanced the cancer may be.

CT offers several advantages over routine chest radiography. First, the use of cross-sectional images allows distinction between densities that would be superimposed on plain radiographs. Second, CT is far better than routine radiographic studies at characterizing tissue density and providing accurate size assessment of lesions.

CT is particularly valuable in assessing hilar and mediastinal disease, in identifying and characterizing disease adjacent to the chest wall or spine, and in identifying areas of fat density or calcification in pulmonary nodules. Its utility in the assessment of mediastinal disease has made CT an important tool in the staging of lung cancer.

Surgical solution

Chemotherapy, Immunotherapy, radiation therapy, targeted therapy and surgery.

Surgery - An operation where doctors cut out cancer tissue.

Chemotherapy - Using special medicines to shrink or kill the cancer. The drugs can be pills or medicines given through veins, or sometimes both.

Radiation therapy - Using high-energy rays (similar to X-rays) to kill the cancer.

Targeted therapy - Using drugs to block the growth and spread of cancer cells.

Doctors from different specialties often work together to treat lung cancer. Pulmonologists are doctors who are experts in diseases of the lungs. Surgeons are doctors who perform operations. Thoracic surgeons specialize in chest, heart, and lung surgery. Medical oncologists are doctors who treat cancer with medicines. Radiation oncologists are doctors who treat cancers with radiation.

Medical devices used

Ultrasound – It is used to visualize the structure of an organ and any major abnormalities.

CT and MRI – Medical imaging techniques to obtain internal images of the body.

Myocardial Infarction (System involved Circulatory system)

Gross Anatomy, Structure and function of Heart

The heart consists of four chambers:

• The atria: These are the two upper chambers, which receive blood.
• The ventricles: These are the two lower chambers, which discharge blood.

A wall of tissue called the septum separates the left and right atria and the left and right ventricle. Valves separate the atria from the ventricles.

The heart’s walls consist of three layers of tissue:

• Myocardium: This is the muscular tissue of the heart.
• Endocardium: This tissue lines the inside of the heart and protects the valves and chambers.
• Pericardium: This is a thin protective coating that surrounds the other parts.
• Epicardium: This protective layer consists mostly of connective tissue and forms the innermost layer of the pericardium.

The left and right sides of the heart work in unison. The atria and ventricles contract and relax in turn, producing a rhythmic heartbeat.

Right side

The right side of the heart receives deoxygenated blood and sends it to the lungs.

• The right atrium receives deoxygenated blood from the body through veins called the superior and inferior vena cava. These are the largest veins in the body.
• The right atrium contracts, and blood passes to the right ventricle.
• Once the right ventricle is full, it contracts and pumps the blood to the lungs via the pulmonary artery. In the lungs, the blood picks up oxygen and offloads carbon dioxide.

Left side

The left side of the heart receives blood from the lungs and pumps it to the rest of the body.

• Newly oxygenated blood returns to the left atrium via the pulmonary veins.
• The left atrium contracts, pushing the blood into the left ventricle.
• Once the left ventricle is full, it contracts and pushes the blood back out to the body via the aorta.

Diastole, systole, and blood pressure

Each heartbeat has two parts:

Diastole: The ventricles relax and fill with blood as the atria contract, emptying all blood into the ventricles.

Systole: The ventricles contract and pump blood out of the heart as the atria relax, filling with blood again.

When a person takes their blood pressure, the machine will give a high and a low number. The high number is the systolic blood pressure, and the lower number is the diastolic blood pressure.

Systolic pressure: This shows how much pressure the blood creates against the artery walls during systole.

Diastolic pressure: This shows how much pressure is in the arteries during diastole.

Gas exchange

When blood travels through the pulmonary artery to the lungs, it passes through tiny capillaries that connect on the surface of the lung’s air sacs, called the alveoli.

The body’s cells need oxygen to function, and they produce carbon dioxide as a waste product. The heart enables the body to eliminate the unwanted carbon dioxide.

Oxygen enters the blood and carbon dioxide leaves it through the capillaries of the alveoli.

The coronary arteries on the surface of the heart supply oxygenated blood to the heart muscle.

Description of the clinical condition - Myocardial Infarction or Heart attack

Normal function of the organ - Pumping oxygenated blood to other body parts; Pumping hormones and other vital substances to different parts of the body; Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation and Maintaining blood pressure

Current pathological state – Damage to the heart muscle caused by a loss of blood supply due to blocks in the arteries.

Reason for the pathological condition – Lifestyle changes, Blockage or narrowing of blood vessels in the heart.

Homoeostasis Change – Blood pressure might drop during heart attack because the heart is too weak to maintain it, as the muscle might have been damaged. The severe pain a person might feel during a heart attack could also trigger an automatic response, which might lead to decreased blood pressure and fainting.

Diagnostic methods

Electrocardiogram (ECG or EKG): Records the electrical activity of heart via electrodes attached to the skin.

Cardiac enzymes test: Blood test for the presence of certain enzymes that leak into blood if heart is damaged.

X-ray: Chest X- ray provides the details of the size of heart, blood vessels and presence of fluid in lungs.

Echocardiogram: To identify whether an area of heart has been damaged by heart attack.

CT scan: To diagnose heart problems, including the extent of damage from heart attacks.

Magnetic resonance imaging (MRI): MRI of heart provides more clear images of the heart.

Surgical solution

Medication

First aid: Oxygen therapy and drugs that reduce blood clotting and help in maintaining blood flow are given.

Thrombolytics: Clot-busting medicines are recommended to dilute the clots formed in the arteries.

Procedures

Coronary angioplasty and stenting: Metal mesh stent is inserted into the artery to keep it open and restore blood flow to heart.

Coronary artery bypass graft (CABG): Bypass surgery that allows blood flow to the heart. Usually recommended depending on the location of the blockage and if the stenting is not suitable.

Post Procedural Therapy

Rehabilitation: Cardiac rehabilitation is a medically supervised personalised program which may include exercise, lifestyle changes and diet is usually recommended.

Medical devices used

ECG – Measures electrical activity of the heart to detect cardiac problems.

Echocardiogram - An imaging test that uses ultrasound to monitor the heart function.

CT and MRI – Medical imaging techniques to obtain internal images of the body.

Cardiac stents are tiny devices that hold open arteries in the heart that have become narrowed or blocked by a buildup of cholesterol plaques. A coronary stent is a tube-shaped device placed in the coronary arteries that supply blood to the heart, to keep the arteries open in the treatment of coronary heart disease.

Stroke (System involved Nervous system)

Gross Anatomy, Structure and function of Nerves (Neurons)

Nerves are the organs that make up the peripheral nervous system (PNS). They serve as information pipelines that allow the brain and spinal cord to communicate with other tissues and organs. Inside the nerves, groups neurons (nerve cells) are organized into bundles called fascicles. Surrounding and holding together each fascicle is the perineurium. This layer appears concentrically laminated and is composed of flattened cells, basement membrane, and collagen fibers. Inside the fasicles, neurons and blood vessels are held in place by a loose connective tissue referrred to as endoneurium. Epineurium, a layer of dense connective tissue, covers and holds together the outer surface of nerves. Arteries and veins are located between the fascicles. Branches of these vessels enter the fascicles and supply the neurons with nutrients and gases.

Normal function of the organ - The nervous system is the highly complex part that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events.

Current pathological state – Occurs when the supply of blood to the brain is reduced or blocked completely, which prevents brain tissue from getting oxygen and nutrients.

Reason for the pathological condition – Lifestyle changes, diabetes, smoking, high cholesterol, high blood pressure.

Homoeostasis Change – A stroke can be caused by bleeding, known as a hemorrhagic stroke, or blocked blood flow called an ischemic stroke. The control of blood pressure (BP), blood glucose level, body temperature, and oxygen saturation, when analyzed separately, is related with successful acute stroke outcome

Diagnostic methods

Physical examination: Patient's symptoms, medical history, blood pressure and blood vessels at the back of the eyes are checked.

Blood test: To find out time taken for clotting of blood.

CT scan: Images of brain can show a haemorrhage, tumour, stroke or other medical conditions.

Ultrasound: To check the blood flow in the carotid arteries and to check for plaque, if any.

Magnetic resonance imaging (MRI): MRI of brain tissue to diagnose ischaemic stroke or brain haemorrhages.

Cerebral angiogram: Dyes is injected to get detailed view of brain and neck blood vessels visible under X-ray.

Echocardiogram: To check for any sources of clots that could have travelled to the brain and lead to stroke.

Surgical solution

Medication

Clot dissolver: To dissolve clots and reopen arteries.

Anticoagulants: Has the effect of retarding or inhibiting the coagulation of blood.

Procedures

Catheter mediated intra-arterial thrombolysis: To attain reperfusion in case of ischaemic stroke or transient ischemic attack.

Angioplasty and stent placement: Widens the blocked artery and a stent is placed.

Aneurysm clipping: To treat a balloon-like bulge of an artery wall known as an aneurysm.

Coil embolisation: To treat aneurysm that may have caused haemorrhagic stroke.

Carotid endarterectomy: To correct stenosis (narrowing) in the common carotid artery or internal carotid artery.

AVM removal: Carried out in case of haemorrhagic stroke.

Post Procedural Therapy

The rehabilitation is advised to start as early as possible upon recovery. Rehabilitation program will be decided as per the necessity and usually focuses on speech therapy; cognitive therapy; sensory and motor skills; and physical therapy.

Medical devices used

CT and MRI – Medical imaging techniques to obtain internal images of the body.

Cerebral Angiogram - A cerebral angiogram is the result of a type of X-ray called cerebral angiography. The X-ray checks the blood vessels and blood flow in your head, brain, or neck by using a special contrast dye.

Part B – Case Study

A 25 year old biker indulged in illegal racing met with a road traffic accident and severed head injury and skull fracture. After resuscitation and operation done for the hematoma it was resorted to do skull implant for his fracture by the orthopaedician

Discuss the case under the following headings

1. Describe the type of bone the skull belongs to

The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton. The skull is made up of a number of fused flat bones, and contains many foramina, fossae, processes, and several cavities or sinuses.

2. Describe the microscopic anatomy of bone

The skull consists of 22 bones (or 29, including the inner ear bones and hyoid bone) which are mostly connected together by ossified joints, so called sutures. The skull is divided into the braincase and the facial skeleton. Its main task is the protection of the most important organ in the human body: the brain

The brain is almost entirely enclosed by the neurocranium with the at the skull base which serve as entry and exit point for blood vessels and cranial nerves. Also, the skull provides support for all of the facial structures.

3. Explain the blood supply of bone

These may consist of only a thin lamella of hard tissue, as in the case of the nasal conchae covered with a mucous membrane. India ink perfusion shows that the bony plates in these instances get their blood supply from the overlying periosteal vessels. The two periosteal vascular plexuses, sandwiching a bony conchallamina, are only infrequently joined together by solitary perforating capillaries. Usually, flat bony laminae, however thin, consist of two bony plates with an interposed medullary layer, as for example, the perpendicular plate of the ethmoid and the vomer in the nasal septum. Their vascularization is analogous to that of the much thicker flat bones of the cranial vault.

4. Elaborate on bone remodeling and new bone formation

Bone remodeling (or bone metabolism) is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation). These processes also control the reshaping or replacement of bone following injuries like fractures but also micro-damage, which occurs during normal activity. Two main types of cells are responsible for bone metabolism: osteoblasts (which secrete new bone), and osteoclasts (which break bone down).

5. Describe the anatomical basis of bone implant

Skull Implants are typically used in the reconstruction of cranial bone defects, such as in post-traumatic surgery of following a tumor resection, an infected craniotomy bone flap or a neurosurgical operation. They are also ideal for surgical bone reconstructions of the cranial and maxilofacial regions, including the orbital floor.

The patient CT data (Computed Tomography) is processed to get the mesh model. The implant is modelled by using modified reverse engineering technique with the help of software. This modelling method is applicable for all types of defects including those beyond the middle line and multiple ones. The implant is designed to fix as per the need. Consequently, the mechanical deformation and equivalent stress are calculated using software with distinctive material properties such as Titanium alloy (Ti6Al4V), Polymethyl methacrylate (PMMA) and polyether-ether-ketone (PEEK). A concept was established and more clinically relevant results can be expected with implementation of realistic 3D printed model in the future

6. Enumerate the indications and contraindications for the bone implant

Indications:

Skull implant that minimizes the risk of infection, promotes the growth of new bone and is easier to install.

The structure and chemical composition of craniomaxillofacial implants shall be customized to mimic the functions of real bone.

Contraindication: Mechanical deformation, equivalent stress factors with material compatibility, intracranial pressure.