Bone Healing and Spinal Fusion

Question 1

Grooves and holes allow for _______

Answer 1

The passage of blood vessels and nerves.

Question 2

What are the 5 categories bones are divided into?

Answer 2

1. Long bones
2. Short bones
3. Flat bones (sternum, pelvis, skull)
4. Irregular bones (vertebrae)
5. Sesamoid bones (Bones are those that are completely surrounded by tendon)

Question 3

2 Different types of bone in the body

Answer 3

1. Cortical (dense, compact bone)

2. Cancellous (more vascular + maybe some bone marrow)

Question 4

Osteons

Answer 4

Concentric layers of bone, or lamellae, arranged around a Haversian canal - which contains blood vessels and nerves.

Question 5

Osteocytes

Answer 5

Bone Cells

Question 6

Volkmann’s canals

Answer 6

Channels that run perpendicular to the Haversian Canals, allowing blood vessels to travel from the outside of the bone to the center.

Question 7

Another name for Lamellar Bone

Answer 7

Cancellous Bone

Question 8

Bone Composition is ____% ______ and ____% ______.

Answer 8

70% Inorganic and 30% Organic

Question 9

___% of inorganic components of bone consist of

Answer 9

95%….of Hydroxyappetite

Question 10

____% of the organic components of bone consist of _____.

Answer 10

93% of….consists of Collagen

Question 11

Collagen

Answer 11

Primary structural material. It is a protein with great tensile strength, and is the main component of bone, cartilage, ligaments, tendons, and teeth. Collagen is the foundation of bone upon which the minerals are deposited.

Question 12

What 4 functions does bone allow for?

Answer 12

Bone allows for:

1. Movement (act as levers allowing for movement)
2. Support (form a frame for the body, allowing us to maintain our shape. The ability of bones to bear weight allows us to stand erect)
3. Protection (cover and protect vital organs. The skull protects the brain. The rib cage protects the heart and lungs. The spine protects the spinal cord)
4. Storage (Bones store minerals for use by the body and house bone marrow, which is re- sponsible for the production of blood cells)

Question 13

Bone Morpho-genetic Proteins (BMP)

Answer 13

Family of non-collagenous proteins (signaling molecules that cells use to communicate with each other) in bone that have been found to regulate bone growth.

Question 14

Cells

Answer 14

The workers within the bone

Question 15

3 Different Bone Cells

Answer 15

1. Osteoblasts - bone building
2. Osteoclasts - bone destroying
3. Osteocytes - star shaped cells that reside in cavities within bone. Osteocytes develop from osteoblasts that get trapped in mineralized bone.

Question 16

2 types of bone marrow

Answer 16

Red - found in the interior of flat bones, vertebrae, and in the cancellous bone of the metaphases of long bones.

 - Red blood cells arise her
 - Platelets arise here
 - Most white blood cells arise here

Yellow - found inside the medullary canal of long bones. Yellow bone marrow is differentiated from red bone marrow by it’s HIGHER CONCENTRATION OF FAT CELLS. Some white blood cells arise from yellow bone marrow. Following severe blood loss, yellow bone marrow can convert to red bone marrow to increase the body’s ability to produce blood cells.

Question 17

Stem Cells

Answer 17

Cells that can DEVELOP into different kinds of cells. They are IMPORTANT to the body’s ability to CREATE and REPAIR TISSUES.

Question 18

Mesenchymal Stem Cells (MSC)

Answer 18

Mesenchymal stem cells (MSC) have the POTENTIAL to DIFFERENTIATE into a VARIETY of cells;

 - Muscle cells
 - Nerve cells
 - Fat cells
 - Osteoblast cells
 - Cartilage cells

Question 19

Hematopoietic Stem Cells (HSC)

Answer 19

Hematopoietic Stem Cells (HSC) can differentiate into a variety of IMMUNE CELLS

 - White blood cells
 - Red blood cells
 - Platelets
 - Osteoclasts

Question 20

Endochondral Ossification

Answer 20

Bone formation via CARTILAGE INTERMEDIATE (Spine, Pelvis, and Extremities)

Question 21

What are the two mechanisms the body uses to create bone?

Answer 21

Endochondral Ossification and Intramembranous Ossification

Question 22

Intramembranous Ossification

Answer 22

DIRECT bone formation (Skull, Clavicle and Mandible)

Question 23

Most bony prominences exist to be _______

Answer 23

Attachment points for muscles, tendons and ligaments.

Question 24

Osteoblasts lay down a collagen matrix called ____

Answer 24

Osteoid

Question 25

Bones increase in height or length through endo chondral ossification at the ________

Answer 25

Growth Plates

Question 26

Bones expand in width through ______

Answer 26

Intramembranous Ossification.

Question 27

Remodeling

Answer 27

The process by which the body continually replaces areas of old necrotic bone with new bone tissue. It is also the process by which bone is made stronger, or resorbed, as a result of how much the bone is being used

Question 28

Howship’s Lacuna

Answer 28

When OSTEOCLASTS make PITS in CANCELLOUS bone in order to REMODEL it.

Question 29

Wolff’s Law

Answer 29

Bone is built where stresses require it and resorbed where stresses are absent.

Question 30

Bone repair happens in 3 stages:

Answer 30

1. Inflammation (0-3 weeks) - hematoma 2. Repair (3 was - 4 months) - (soft callus, then hard callus) 3. Remodeling (4 months - 7 years)

Question 31

What is the one important distinction between fracture healing and fusion?

Answer 31

The large volume of graft material that eventually needs to be remodeled in fusions.

Question 32

An important additional step in bone remodeling in fusions (vs. fx) is ______

Answer 32

The additional step in the REPAIR PHASE that requires blood vessels to grow into the graft in order to supply nutrients and stem cells to that region.

Question 33

To maximize a fusion you should create the following 4 conditions:

Answer 33

1. Bony Apposition - in order for a fusion to occur, the two bones need to be in contact 2. Maximize Surface Area - The more boney area that is in CONTACT with the ADJACENT bone, the more likely a fusion will occur, and the more STABLE that fusion will be. 3. Bloody Pathway - Blood VESSELS bring the -oxygen -nutrients -stem cells to the area that are needed to build bone 4. Stable Fixation - EXCESSIVE movement can DISRUPT the formation of bone at the graft site. This can result in a non-union.

Question 34

What are some other factors that can have a negative effect on bone healing?

Answer 34

- Lifestyle - Poor Nutrition - Tobacco - Comorbidities - Diabetes - Rheumatoid Arthritis - Medications - Steroids - Radiation - Cytoxic (chemo) Drugs

Question 35

4 types of bone graft

Answer 35

Autograft—Bone relocated from elsewhere in the patient’s body. Allograft—Bone taken from another member of the same species. Xenograft—Bone taken from a member of a different species. Synthetic—These substitutes for bone grafts are created artificially to mimic bone in the body.

Question 36

3 Properties of Bone Graft

Answer 36

Osteoconductive—An osteoconductive graft has the ability to provide the framework (scaffold) for new bone growth. An osteoconductive graft satisfies the structural re- quirements for a fusion. Osteoinductive—An osteoinductive graft has the ability to induce bone growth. An osteoinductive graft satisfies the chemical requirements for a fusion. Osteogenic—An osteogenic graft has the ability to grow into bone. It contains live bone cells. An osteogenic graft satisfies the biologic requirements for a fusion.

Question 37

Synthetic Grafts include:

Answer 37

Calcium Sulfate

Question 38

What are the different circumstances for bone growth,

Answer 38

- INITIAL bone formation in a FETUS - GROWTH of the skeleton during CHILDHOOD - RENEWAL of the skeleton throughout ADULTHOOD via REMODELING - FORMATION BETWEEN bone FRAGMENTS following a FX - FUSION of two bones following a CORRECTIVE surgical PROCEDURE