The Spine

SPINE SURGERY SERVICES

The Orthopedic Center's spine specialist, Dr. Benjamin Knox, routinely performs spine surgery. Dr. Knox is a graduate of Dartmouth College and Johns Hopkins Medical School, and completed postgraduate surgical and orthopedic residencies at Johns Hopkins and University of Pittsburgh. He then finished a fellowship in spine surgery at the Carolinas Medical Center, Charlotte's main teaching hospital. Dr. Knox has practiced with a special interest in spine since 1992, and has focused exclusively on spine since joining The Orthopedic Center in 1997.

Treatment Philosophy

Dr. Knox is strong advocate of conservative spine surgery. This approach emphasizes the need to prescribe surgery only when there is a good likelihood of the patient benefiting. "There are too many unnecessary spine surgeries performed in the United States," observes Knox, "and the problem is getting worse. We live in a very consumer-driven, fix-it-now culture. Many people have the idea that with modern medical technology so advanced, doctors should be able to relieve any distressing condition. Unfortunately, the common backache and the common 'pain in the neck' are not reliably cured by surgery."

"We have a lot of good science now about what spinal operations work well, and on what kind of patients. If the surgeon can apply this science to his patients properly, most unnecessary operations can be avoided. The surgeon needs to resist the temptation to offer surgery to a patient solely based on the patient's perception of how bad he or she is. Patients' perceptions can be quite misleading. One person may perceive a frequent backache as a minor annoyance and unavoidable consequence of aging, and yet another person with the same sort of pain may be deeply distressed about an unacceptable limitation on their lifestyle."

Accurate diagnosis is the key, says Dr. Knox. With a proper spinal history and physical, which includes screening for other orthopedic and neurological conditions, the diagnosis can usually be narrowed down. Imaging studies such as X-rays, MRI, CT scan, or bone scan will usually confirm the diagnosis. Occasionally blood work, nerve testing, or consultation with a neurologist or neurosurgeon is ordered to complete an evaluation.

Conservative Non-operative Management

Most spinal conditions do not require surgery. Furthermore, many conditions that might be treated surgically can also be managed by other treatments. Often, a trial of conservative treatment, such as physical therapy, medications, or spinal injection is recommended before a final decision for surgery is made. Some conditions, particularly lumbar spinal stenosis, can be safely observed for months or even years, and surgery performed later if and when worsening occurs.

Types of Conditions Treated Surgically and Why

These fall into four broad categories: pinched nerves, instability/fractures, destructive lesions, and painful disc degeneration. The first three categories involve simple mechanical problems that have simple mechanical surgical solutions. The last category is both complicated and controversial!

1. Nerve pressure can affect either spinal nerves (common) or spinal cord (less common). The spinal nerves branch off the spinal cord and exit the spinal canal through pairs of windows called foramen. Pinched spinal nerves result in pain, numbness, tingling, or isolated weakness in an arm or leg. Pinched spinal cord results in weakness, clumsiness or loss of balance, widespread numbness, and occasionally loss of bowel or bladder control. Nerve pressure can result from herniated disc, bone spurs, cysts, and tumors. Surgical treatment always involves relieving the pressure, know as decompression.
2. Instability can result when the connections between two vertebrae become weakened, often as a result of wear over time. This usually results in a condition know as spondylolisthesis. The body perceives this slippage or excessive movement as painful. The slippage can sometimes contribute to nerve pressure as well. Fractures are injuries to the vertebral bones where the bone breaks, and the weakened bone cannot carry its normal load without pain. These unstable conditions are usually treated by fusion, in which two or more bones are made to knit together into one, eliminating the weakness. Metal hardware is often used to reinforce and stabilize a fusion and is known as instrumentation. Compression fractures are a special pattern of broken bone that is sometimes treated in the elderly by a special injection technique known as kyphoplasty.
3. Destructive lesions are disease conditions that actually eat away and weaken bone, often leading to fracture, nerve pressure, or both. Tumors and infections are the usual cause, but again, not all cases will be treated surgically. Surgical treatment involves first removing the diseased tissue and bone, and relieving any nerve pressure. The removed tissue is then replaced with a graft, usually a piece of bone from a bone bank that is fitted into the empty space and bears the weight. Then the entire area is fused and usually instrumented for future strength.
4. Painful disc degeneration. Also known as discogenic pain, this is pain that results, basically, from the loss of the normal shock absorber function of the disc. Most discs lose their cushioning ability with age. Why some discs hurt more than others is poorly understood. Although usually managed conservatively, painful disc degeneration can be treated surgically by either fusion of the disc, or by disc replacement. Two-year satisfaction rates for fusion in the lower back are about 60-70% on average. Certain very specific patterns of disc degeneration may have a better prognosis. Two-year results for disc replacement appear to be slightly better than fusion. Long-term results for both procedures appear to be similar to no treatment. Similar procedures in the neck have a better outcome than for the lower back. Conservative spine surgeons are generally skeptical about these procedures. They typically recommend them only for patients who are both very disabled by their pain, and demonstrate a high degree of motivation to return to a more active, productive life. Dr. Knox has received certified training in disc replacement, and does perform these procedures occasionally in patients who meet the appropriate criteria. A minimally invasive treatment for lumbar (low back) disc degeneration known as Intradiscal Electrothermal Therapy (IDET) can reduce back pain in some patients in the early stages of disc degeneration.

More on Specific Conditions and Operation

In this section, the conditions are discussed from the perspective of a patient who has not improved on conservative management and is considering surgical intervention.

Lumbar Disc Herniation. This common condition results when the disc material between the bones oozes out into the spinal canal, causing nerve pressure and radiating leg pain. Microdisectomy is performed using a minimally invasive technique. Using a small muscle-spreading access tube and a high-powered operating microscope allows removal of the disc material through a ¾" incision. Pain relief is usually immediate and the patient can go home the day of surgery. Return to work is about three weeks.

X-Stop is a less invasive option for the treatment of lumbar spinal stenosis. Using a 2-3" incision, a titanium metallic spacer is inserted between the spinous processes, which spreads the 2 vertebrae apart and indirectly creates more spaces in the spinal canal. The procedure carries slightly less risk than laminectomy. Long-term outcoume for the procedure is not known, but 4-year follow-up on U.S. patients has shown 80% success rate. The ideal candidate for X-Stop is probably an older, physically less active patient, particularly if there are co-existing medical problems such as diabetes, heart, or lung disease.

Lumbar Spinal Stenosis. This is narrowing of the spinal canal due to loss of disc height, bone spur formation and kinking of ligaments. Patients usually complain of aching or tiredness in one or both buttocks and legs, worse with standing or walking. Limited disease can sometimes be handled by a minimally invasive approach, but most patients are best treated by a standard technique know as laminectomy. The spinal canal is opened and the pinched nerves are freed from the surrounding compressing tissues. Hospital stays average 2 days and recovery is about 6 weeks.

Spondylolisthesis Slippage of one vertebra on another can be due to disc wear in older patients. In younger patients a weak spot in the bone known as a spondylolysis can cause a similar problem. Nerve pressure from the slippage often means that patients have both back and leg pain. Bone morphogenetic protein is now routinely used to avoid the need for taking bone from the hip to graft the fusion, which cuts down on surgical time, blood loss, and pain. Hospital stays average 3 days and full recovery averages 4-6 months while bone healing occurs. Light duty is often possible after 2 to 3 months.

Cervical Disc Herniation. Similar to lumbar disc herniation, disc material oozes into the spinal canal and causes pain radiating down into the arm and often into the shoulder blade area. A small incision in the front of the neck allows removal of the disc material microscopically by going through the disc space into the spinal canal. The disc space is then fused (anterior cervical fusion or ACF) with a plug of bone, usually from the bone bank (although hip can be used if the patient prefers). Pain relief is usually immediate and dramatic. Hospital stay is overnight and recovery consists of just three weeks in a soft collar. Disc replacement instead of fusion is in FDA trials and is not available to the general public at this time.

Select patients may be a candidate for posterior microdiscectomy. This minimally invasive procedure involves inserting a small tubular retractor through the muscles in the back of the neck and removing the disc material without performing a fusion. Less muscle trauma, pain and rapid healing make this the procedure of choice in younger active patients and athletes.

Cervical Stenosis
When nerve pressure in the neck results from multiple factors like narrowing or bone spurs, and not just disc material, the condition is more properly referred to as cervical stenosis. Symptoms and surgical treatment are very similar to cervical disc herniation. Occasionally, more complex problems may require larger operations done through the back of the neck, or so-called "front and back" surgery with incisions on both the front and back of the neck.

Osteoporotic Compression Fractions
These common fractures result from softening of the bones, usually in the elderly, known as osteoporosis. The vertebral body, which is the cylindrical weight-bearing part of the vertebra that sits in front of the spinal canal, collapses due to weakness. This is analogous to putting one's heel on a soda can and stepping down on it. In kyphoplasty, a true minimally invasive procedure, a catheter is inserted into the vertebral body and a balloon is inflated to expand the collapsed bone. The space is then filled with bone cement that strengthens and holds the bone in place. Pain relief is typically immediate, and the procedure is usually done as an outpatient.

Discogenic Back Pain
Surgery for this condition involves either a fusion (anterior lumbar interbody fusion, or ALIF) or disc replacement. Both operations are done from the patient's front side, going through the abdomen and removing the disc material between the bones. In fusion, the disc space is grafted, and the two vertebras eventually knit together into one. Complete bone healing can take a year, but light work can begin at about 3 months. In disc replacement, approved by the USA's FDA in 2004, an implant of metal and plastic is inserted between the bones that allow movement. Recovery coincides with muscle healing in the incision, about 6 weeks. Pain relief for disc replacement, with zero being no pain and ten being the worst pain possible, averages a change from 7.2 before surgery to 3.1 two years after; for fusion the change is from 7.2 to 3.7. The very long-term risks of disc replacement are not known, and U.S. health insurance companies have been slow to authorize the procedure. Researchers are hopeful that long-term results for disc replacement will be better than fusion, since in theory less strain is placed on the adjacent discs in the spine.

In patients with disc degeneration in the early stages, a minimally invasive treatment known as Intradiscal Electrothermal Therapy (IDET) can significantly reduce back pain. The procedure involves inserting a thin catheter through a needle into the center of the pain-producing disc. The inside of the disc is then heated by the catheter, which causes changes in some of the tissue in the disc. It is not known whether the improvement results from a healing response, deadening of pain fibers, or some other factor. Studies have shown a clear benefit, with about 60% of patients responding to treatment. On average, a patient who responds will experience a 50% reduction in pain.

Discogenic Neck Pain
Surgery for this condition involves ACF (described above), except that no nerve pressure needs to be relieved. Success rates are consistently better than lower back fusion, with patient satisfaction at 80%. Disc replacement is a theoretical option for this condition as well, but is not yet approved in the USA. The present FDA trials are examining the use of disc replacement in the neck for cervical disc herniation only not for discogenic pain.

Links
www.spineuniverse.com