About the Spine

The spine is a very complex system of bones and joints, soft tissue (discs, muscles, and ligaments), and nerves that provides for support,motor function, sensibility, and proprioception (ability to sense the position of one’s body or extremities) of the limbs and body. The bony structures serve to provide structural support to our muscle and tissue and serve to anchor the extremities to the central skeleton while providing an armor of protection for the delicate spinal cord and nerves it surrounds.

Because the spine is a very complicated system, few people truly understand the association of the symptoms that arise from abnormalities of the spine and the actual cause of those symptoms. Elucidating the source of the pain, numbness, tingling, imbalance, and other neurologic symptoms that can arise from abnormalities of the spine requires an elaborate algorithm of evalutions, including radiographic studies (Xrays, MRIs, CT scans), physical examination findings, and diagnostic tests such as nerve testing, discography, and injection therapy to name a few. It is the detailed evaluation by a trained expert in the field of spine surgery that will help to localize the source of a patient’s problem and provide the best hope of addressing and hopefully, ameliorating it.

Many patients with spinal disorders complain of pain, numbness, tingling, and weakness of the upper extremity (arms) or lower extremity (legs). Patients with nerve or spinal cord compression of the cervical spine or neck commonly report symptoms of “migraine headaches”, tension headaches, occipital headaches, and neck pain. This pain is typically associated with pain in the back of the neck, pain along the base of the skull (the back of the head) and can radiate to the top of the head and forehead.

They may also experience pain between the shoulder blades, difficulty maintaining balance, and even bowel or bladder incontinence if spinal cord compression is severe. It is even possible to have difficulty with vision, pain behind the eyes, facial tingling, facial numbness, or facial pain. Spinal nerve compression in the midback (thoracic spine) can result in pain in the midback and pain radiating around the chest wall or flank. Those with spinal cord compression may report difficulty with balance and bowel and/or bladder incontinence. Lumbar (low back) nerve compression may result in leg pain, tingling, numbness, and weakness. Very severe nerve compression below the spinal cord can, rarely, cause difficulty maintaining bladder or bowel control as well. This is termed Cauda Equina syndrome and is one of the rare emergencies of the spine.

When spinal discs are torn, whether it is the result of trauma or the aging process, a cascade of events occurs. It is possible to have a large piece of the disc herniated through the tears in the outer rim of the disc. This is termed a disc protrusion or herniated disc/nucleus pulposus. It occurs when the central, dense gelatinous part of the disc squirts out through a defect in the outer rim of the disc. This condition can cause acute onset of severe pain, numbness, tingling, or weakness of the upper extremities when occurring in the neck or the lower extremities when occurring in the low back. The radiation of pain from nerve compression or inflammation is known as radiculopathy. Radiculopathy in the lower extremities is also known as “Sciatica”. This is the radiation of pain along one or more nerve pathways in the legs.

Some patients have primarily low back pain. This can be the result of a tear in the disc (annular tear) with or without spinal nerve compression. Subtle spinal instability may occur when the disc architecture is disrupted. This instability is very difficult to identify. Patients with this condition may experience severe back pain, shifting of the back to one side (lateral shift), a catch in the back with certain movement, an inability to stand upright, and even radiation of pain into the groin or thighs. Xrays are not always able to identify subtle, clinical instability as they evaluate the resting position of the spine. Flexion and extension Xrays are commonly ordered to see if there is evidence of abnormal motion of the spine. However, even flexion and extension Xrays only show the extremes of spinal motion. Many patients have instability that occurs in the mid-range of spinal motion, which is undetectable with any currently available radiographic test.

These symptoms may manifest as severe low back pain that radiates along the back in a belt-like distribution, pain to the right or left buttock, pain radiating to the groin (groin pain), and occasionally, pain into the legs that typically stops above the knee. This is different from typical radiculopathy (nerve pain in the extremities) where pain usually follows a clear line down the extremity along the path of the nerve being compressed or irritated. Back pain is one of the true diagnostic dilemmas in the field of spine. Many conditions can result in back pain, thus, the evaluation requires a detailed understanding of the potential sources of back pain. If the disc appears to be the source of the pain and all conservative efforts have failed to provide relief, your doctor may decide surgery is the next best option.

Surgery should always be considered the last option, but is sometimes, the best option, nonetheless. If the disc is suspected to be the source of back pain, a preoperative study called a discogram can help to identify the disc or discs causing the unremitting back pain some patients experience. This test is designed to pinpoint the exact discs responsible for a patient’s daily pain and to identify and structural abnormalities that may or may not be visible on an MRI as well as the first normal disc above the abnormal discs. It is an important test for patients with severe back pain, as the presence of an abnormal MRI does not always correlate with the need for surgery. It is not uncommon the have abnormal-appearing but non-painful discs and at times, normal-appearing discs may in fact, be the source of pain. This can only be elucidated by a well-controlled discogram with an experienced discographer using very tightly controlled test parameters to maximize the accuracy of the results. Without it, an improper surgical plan may be designed with low likelihood of surgical success.

When the disc architecture becomes disrupted, the disc is less capable of providing stability to the spine. Over time, it can degenerate (become arthritic). This is termed degenerative disc disease but essentially means arthritis of the spine. When the disc becomes more diseased, it provides less padding between the spinal bones (vertebral bodies). This results in loss of the protein content in the disc and with it, the normal water content of the disc (approximately 90% of a healthy disc) begins to dissipate or leach out. This is termed disc dessication (or drying out) of the disc. The disrupted disc architecture results in loss of disc height and subsequent bulging of the outer portion of the disc.

This bulging can result in compression of the spinal nerves. As the disc flattens out, it allows more motion between the spinal bones which places stress on the joints in the back of the spine (facet joints). This added stress can cause overgrowth, or hypertrophy, of the tissue surronding the joints and the bone itself. The ligament under the bony roof of the spinal canal also absorbs more stress and becomes thickened.

The disc bulging toward the spinal canal coupled with the overgrowth of the joints and ligament cause crowding of the nerves. This is termed stenosis. As stenosis progresses, nerve compression becomes more severe. This may manifest as numbness, tingling, pain, and/or weakness of the legs. Stenosis symptoms are typically worsened by standing or lying flat and improved by sitting or leaning forward. Many people with this condition find that leaning forward on a shopping cart or sitting frequently relieves the symptoms in the legs.

A spine surgeon is either a neurosurgeon or orthopaedic surgeon who specializes in the treatment of disorders of the spine. Few surgeons actually perform sub-specialty training in the field of spine surgery, termed a spine fellowship. This is typically additional training that occurs after one has become a specialist (either a neurosurgeon or orthopaedic surgeon). This training provides a higher level of expertise in treating disorders of the spine.

A fellowship-trained spine surgeon is best equipped to address pathology of the spine. Through a multi-disciplinary approach with pain specialists, neurologists, and radiologists, the best non-operative options for relief should be sought primarily. If this approach fails, it is sometimes necessary to consider surgical options to address persistent symptoms related to spinal disorders.

 

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