We would be lost without our skeletons, something that vertebrates including us figured out a long time ago. Unfortunately, like many supporting structures, time, with wear and use, may weaken them.
How to maintain and strengthen our bones was brought forward by Dr. Holly Coward, Carolina Meadows’ medical director, in her recent excellent Lecture Hall talk about osteoporosis. Her examination of the causes of osteoporosis, when it starts, how to decrease it and how to be careful when we have it was very helpful.
What my radiologist colleagues and I see in bones is very different when looked at with a microscope. In osteoporotic bones with various X-ray techniques, we know that bones must be weakening as their density decreases. We see it when the spine ages and compression fractures occur. We see osteoporosis in resting bones as fractures heal. They can be weakened in various anemias, leukemia and congenital abnormalities such as osteogenesis imperfecta in babies and children.
The hard shell of compacted cells or cortex of our long bones, skull and vertebral bodies stands out in X-ray. So do the interlacing struts of cancellous bone between the cortices. These struts or trabeculae are strong. This is especially true when there is maximum pressure on the neck of the femur when walking. Unfortunately, it is a place where hip fractures can occur.
The cortical and trabecular bone is called the bone mass. The red marrow with blood cells of the young is between the trabeculae. It is largely replaced with fatty marrow as we age. Both compact and trabecular bone can be seen well with CT. Marrow is displayed best with MRI.
In normal bone as well as pathologic conditions, there is a very different microscopic landscape. The microscope shows rings in a parquetry of bone cells. A micro-millimeter canal system between the cells allows the permation of blood with calcium, phosphorous, proteins and other elements for bone metabolism.
As we age, disturbance of that metabolism is the major cause of osteoporosis. Dr. Coward pointed out multiple facts about osteoporosis: 40 million Americans across the age spectrum have low bone mass.
Osteoporosis could bankrupt Medicare because it causes more fractures than hear attacks. The mortality of the aged wit hip fractures approaches 25 percent.
Other factors include extended steroid use, particularly in rheumatoid arthritis, smoking, excess alcohol and lack of exercise. Marked forward curvature of the thoracic spine due to osteoporosis can cause crowding of abdominal organs including the stomach. Gastric fluid reflux into the esophagus may then produce esophagitis.
The degree of spinal osteoporosis that is developing can be checked with a ruler. A loss of height of 1/2 inch or more in one year is a physical sign. Dual Energy X-ray Absorption scans (DEXA) of the spine, hip and forearm bones can provide a baseline for treatment.
Dr. Coward emphasized the hallmark steps for arresting osteoporosis, calcium and vitamin D intake, vitamin D to promote intestinal absorption of the calcium. Equally important is frequent moderate exercise. Exercise most likely maintains better bone blood flow but also strengthens musculature.
Medications such as bisphosphonates or estrogens may be helpful and should be considered with our physicians if the risk for osteoporosis increases. If acute vertebral body fractures occur, vertebroplasty is a consideration, but complications can occur. Calcitonin can be tried for pain management if vertebroplasty is not an option.
Dr. Coward’s talk was comprehensive and enlightening. Our bones can be better for it.
From Dr. James Scatliff, a resident at Carolina Meadows and a former faculty member at Yale and the UNC School of Medicine.