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------------------------------------------------------------ AGING AND HORMONAL CHANGES ------------------------------------------------------------ All living things grow old. The spine is not immune to the process and in fact ages more rapidly than other parts of the body. One of the trademarks of the aging process is the gradual dessication or drying out of body tissues. It seems odd that a man or woman will live comfortably to an age of 80 yet begin to show signs of spinal aging in the early twenties. However, at that early age it can be demonstrated that the intervertebral discs are starting to lose their flexibility and moisture content. Aging has begun. This may be due to our genetic makeup as well as the relentless force of gravity constantly pressing on the unstable upright spinal column. The discs, as we learned from an earlier chapter, comprise about 25% of the length of the spinal column. As aging takes place they gradually become compressed, lose moisture and shrink. Joint motion, flexibility and all-important shock absorbing qualities gradually diminish. Chronic spinal strain thus begins. These mechanical stresses are transferred to the vertebrae, supporting muscles and ligaments. The ligaments holding the structure together may be pulled or lifted from the vertebral surfaces which in turn attempt to minimize the instability by creating bony spurs or growth projections to fill the missing spaces. This can eventually lead to osteoarthritis as the spine shrinks in overall length. A classic and for the most part inescapable fact of aging. However if the supporting muscles and structures of the spine are kept in good shape with judicious exercise habits, the pain and loss of flexibility is minimized to a certain extent. In the back and spine, as no other site of the body, the truism "use it or lose it" has clear and absolute meaning. Osteoporosis or osteopoenia can be a side effect of aging. Gradually the bones can become brittle and spongy, thus losing critical bone tissue mass. Normal bone tissue is not a static, dead tissue. It may seem dead and brittle, but it is definitely not dead. A constant turnover of bone calcium and other tissue takes place at all times within bones. One perspective is that every bone in your body is replaced, molecule for molecule, every 6.5 years. Bones also react to stress and fractures - healing and bonding together to reproduce the original load bearing characteristics and also enlarging slightly along the axis of stress. Put a bone under pressure and, within limits, it will attempt to grow stronger and deposit additional calcium to counteract the stress. Astronauts in the gravity free environment gradually lose calcium. In a sense gravity is both friend and foe: it provides the stress which keeps bones strong yet it eventually collapses and compresses our upright spinal column. A biological paradox at best. Bone has two primary anatomic structures: 1) matrix, the protein "sponge" into which calcium is deposited and hardened. 2) An intercellular tissue which fills the hollow pores of the matrix with solid calcium salts - a sort of glue which binds the tissue and calcium together. The matrix onto which calcium is deposited is produced by osteoblast cells. Meanwhile another variety of cell, the osteoclast, reabsorbs bone which has aged and must be removed. Thus two opposing forces are at work governed by different cells: one deposits bone mass, the other removes it. Usually the chemical and cellular forces are in balance. However when the osteoclasts gain the upper hand, more bone is removed than is replaced. This is the mysterious mechanism which is the basis of the disease osteoporosis. However we need to go a little further to learn about the specific dynamics of this process and how it affects the spine. The outer portion of bone is hard and is called the cortical layer. The inner core is softer and spongy and is known as the cancellous layer. The inner cancellous layer is the region where dynamic chemical and cellular activity takes place. Calcium salts are moved around, primary blood cells are generated and a host of other process occur within this bone core area. And this is the central clue why the vertebrae of the spine seem to be uniquely prone to osteoporosis, certain infections and some tumors. It is because a LARGER region of the vertebrae is CANCELLOUS (soft tissue - dynamic cell reactions) than cortical (relatively stable - slow chemical turnover). Because of this important difference, the bones of the spine are much more easily disturbed by chemical, hormonal or metabolic imbalances in other parts of the body. In this respect, the structure of the vertebrae of the spine are dramatically different from bones in the other parts of the body. Why do these vertebral bones have this unique structure? Some anthropologists speculate that our own evolution is to blame. Our rapid adoption of an upright posture REQUIRED the bones of the spine to become more cancellous and dynamic in cellular activity to allow for an unstable and inherently risky upright spinal posture. Nature and evolution simply did the best it could given the short time frame needed to adopt an upright posture! A particular hormonal imbalance, usually associated with the menopause of women, has been linked statistically to osteoporosis. Apparently the shifting tides of hormones produced at menopause can lead to gradual thinning and spongy weakening of the vertebral bones whose uniquely dynamic and chemically sensitive cancellous core is susceptible to the hormone triggered event we call osteoporosis. X rays conclusively reveal the weakening of the vertebral bodies in osteoporosis. The attempted treatment, although by no means conclusively successful, is hormone replacement therapy. Frequently this means administration of both male (testosterone) and female (estrogen) hormones. Calcium tablets and vitamin D may also be prescribed. The benefit of this method of therapy is open to debate among members of the medical community, although it is usually attempted as the the best available treatment for now. Hip fractures in elderly patients have also been reduced by providing vitamin D and calcium within an enriched dietary plan. In the case of senile osteoporosis, a variation not related to menopause, different hormones are usually administered along with calcium and vitamin D tablets. The results are also not clearly demonstrated, but are nonetheless frequently attempted. Once vertebral collapse occurs, back braces or surgery may be required. Bed rest is not always the treatment to use in this situation because once bed rest or disuse sets in, the spongy vertebrae begin to deteriorate rapidly. Lack of use tends to accelerate the process of bone loss in most conditions involving osteoporosis. Bones need a certain amount of use and exposure to gravity to keep calcium deposits in place. Bed rest can accelerate calcium loss. One malady related to osteoporosis is the gradual expansion of the intervertebral discs into the upper and lower plates - the roof and floor - of the bony vertebrae themselves. However, if the vertebrae have already lost most of their elasticity, this likelihood is diminished. Unlike a disc rupture which takes place either into the spinal canal or outwards towards the lateral side of the spinal column, disc expansion can take place directly into the weakened mass of the vertebral body itself in cases of osteoporosis. ------------------------------------------------------------ INFECTIONS ----------------------------------------------------------- Infections and tumors of the spine are rare indeed, but worth mentioning in any discussion of maladies which affect the spine. The advent of modern antibiotics has erradicated many spinal infections, but nonetheless prudent physicians consider and test for the presence of spinal infections when other causes cannot be assigned. Tuberculosis is usually associated with a severe infection of the lungs but has been reported in medical literature to also infect the vertebrae of the spinal column. The bacteria which causes tuberculosis is easily carried in the blood stream and can take up residence in the spongy core of the vertebrae. Since the bacteria cause slow growing abscesses and eventual formation of scar tissue, patients may eventually report loss of motor or other nerve function as the spine is compressed or pinched by the encroaching scar tissue and gradually collapsing vertebral bone mass. In severe cases of tuberculosis of the spine, partial or complete paralysis of the lower body has been reported if spinal nerves are severely affected. A low grade fever, common with most bacterial infections, is an early manifestation. Profuse sweating at night, back pain, vomiting and a limit in the range of motion of the back may follow. A chest X ray may show no evidence of lung involvement. A biopsy with a hypodermic syringe is the conclusive laboratory test for presence of infection. This procedure removes a small quantity of fluid from a suspected spinal abscess which is sent to a medical laboratory for positive identification of the tuberculosis bacillus. Surgery and spinal fusion is the corrective method of choice in advanced stages of the disease. The bacteria which infects the spine selectively attacks the bone mass of the vertebrae and seldom involves the flexible discs since they do not contain oxygen and blood which the bacteria requires for growth. A serious outbreak of antibiotic-resistant tuberculosis began to surface in early 1992 and was reportedly seen in New York and regions of Florida. Although initial reports suggest it is primarily linked to tuberculosis of the lungs, spinal involvement may evolve as the bacteria spreads into the general population. New antibiotic compounds are currently under investigation to treat this unusually virulent form of tuberculosis which could eventually cause a new pandemic and reversion to earlier methods of treatment such as sanitorium care and strict isolation. Meningitis refers to an infection of the spinal cord. A variety of bacteria and virus organisms have been implicated as causing this serious disease. Symptoms include, but are not limited to, stiffness of the neck and spine and painful spasms. The meningoccocus bacteria, a common cause of meningitis, may also cause fever. However, viral organisms causing meningitis may not always produce fever. The early stages of meningitis may begin as simple back pain. A common diagnostic test is for the physician to test muscle reflexes in the lower extremities. If specific lower body reflex sites are hyperactive (overly reactive to touch), meningitis is a strong suspect. Polio, or more properly poliomyelitis, involves similar viral infection of the spinal cord. However, common anti-polio vaccines have almost erradicated this disease in the United States, but it does continue to surface in parts of Africa and remote regions of the World. Spondylitis is a bacterial infection of the spine usually involving the common staphylococcus bacteria which may be carried to the site of the spine by the bloodstream. The vertebral bones are usually infected and the bacteria may spread from one vertebrae to the next. Back pain, fever and loss of appetite may be present in spondylitis victims. X rays of the vertebrae in early stages of the disease may show little evidence of infection, but as the bacteria grow, X rays and biopsy (drawing infected fluid from the vertebra with a hypodermic needle) provide conclusive identification of this bacteria. Antibiotics are usually able to halt the spread of the infection. Surgery may be required if the vertebrae have been severely damaged or contain large abscesses. ------------------------------------------------------------ TUMORS ----------------------------------------------------------- Discussing tumors immediately brings to mind a sinister word: cancer. However it is important to note that cancer applies to malignant or spreading tumors which invade and destroy healthy tissue and bone. Benign tumors generally do not spread throughout the body, can be removed by surgery and may present little actual tissue damage. Thankfully, tumors both benign and malignant of the spine are relatively rare. Malignant tumors are generally divided into two classes: Primary and secondary. Primary tumors originate in a specific tissue or bone. Secondary tumors, also known as metastatic tumors, have spread to a specific tissue from another primary site of origin. The most common sites where primary malignant tumors begin are the prostate gland, breast, lung, kidney and thyroid. These are the classic sites where the majority of cancers originate. Primary malignant tumors may eventually involve bone, especially the large bones of the spinal column and lumbar vertebrae because of their spongy, blood rich cancellous core which was discussed earlier. Diagnostic methods to determine the primary or original site of the cancer are frequently undertaken by a physician and may involve tests such as X rays of the lung, thyroid studies with radioactive materials, pyelograms of the kidney, mamograms of the breast, ultrasound studies of the prostate and biopsy of the spine. Treatment may involve a combination of radiation, chemotherapy and hormones which is directed at the primary or original site of cancer growth. Treatment of the secondary site may involve a similar or modified treatment with radiation and chemotherapy as well. Malignant tumors can involve areas other than the bones of the spine. Liposarcomas and fibrosarcomas are malignant tumors of fatty tissues and muscles of the back respectively. Schwannoma is a malignant cancerous invasion of the spinal cord. Malignant tumors of the spine are usually secondary - they have spread to that location from another part of the body. In fact the first sign of cancer in another part of the body, the prostate or kidneys for example, is the presence of back pain which results from the invasion of the cancer to the bones of the spine or soft tissue of the back from its primary site. Some physicians note that if back pain increases when the patient lies down, a tumor may be a probable culprit - although this simple clinical observation must be corroborated with additional tests. Other than the secondary tumors we have discussed, a few primary tumors of the spine have also been detailed in medical literature. Several rare types have been reported: 1) Osteogenic sarcoma, a rare and extremely deadly form of cancer which grows rapidly. 2) Multiple myeloma which reflects an abnormal rapid growth of bone marrow cells. 3) Chordoma which is usually slower growing and may confine itself to localized areas of the spine. Chordomas can be surgically removed with moderate success, but can recur with time although their growth and reappearance is slow. Sarcomas are usually fast growing and more resistant to surgery, radiation and chemotherapy - and thus among the deadliest of tumors. This tutorial is merely a starting point! For further information on back care and back pain, be sure to register this software ($25.00) which brings by prompt postal delivery a printed, illustrated guide to back pain written by a physician plus two software disks. From the main menu select "Print Registration Form." Or from the DOS prompt type the command ORDER. Mail to Seattle Scientific Photography (Dept. BRN), PO Box 1506, Mercer Island, WA 98040. If you cannot print the order form, send $25.00 to the above address and a short letter requesting these materials. End of chapter.