When patients with spinal deformities such as scoliosis and kyphosis are carefully screened and prepared, surgical treatment results in significant relief of pain and fatigue, as well as cosmetic improvement. But in a small number of cases, additional intervention may be necessary.
“Patients with deformities that progress, whose symptoms persist or worsen despite surgery, or who develop new or different symptoms, require careful evaluation,” explains Matthew Cunningham, MD, PhD, assistant attending orthopedic surgeon at Hospital for Special Surgery (HSS). “Whenever possible, patients are treated non-surgically, but there are instances when revision surgery is recommended.”
For many patients with spinal deformity, the goal of initial surgery is to create a fusion (essentially a welding together of the vertebrae) in the affected area. In order to promote healing and maintain alignment, fusions are secured with instrumentation, which can include rods, hooks, screws, or cages.
Pseudarthrosis, or failure of the bone to heal properly following fusion surgery, is one reason patients may require revision surgery. This and other conditions may contribute to progressive deformity developing above or below the surgical site, as the non-fused vertebrae respond to additional forces being placed upon them; in addition, disks in the spine may become compressed or slip out of place, resulting in conditions such as disk herniations, degenerative disk disease, and spondylolisthesis.
Others reasons revision surgery may be necessary include:
Achieving a thorough understanding of the patient’s condition prior to the initial surgery - as well as the nature of the surgery, and how they have been symptomatic following their initial surgery - helps guide the orthopedist’s treatment recommendations. “Expertly-performed prior surgery can unfortunately still fail, so we need to know why the first procedure didn’t work and what can be done now to improve the patient’s symptoms,” says Dr. Cunningham.
In addition to pain and fatigue, a small number of patients may seek medical care when they develop altered trunk position (termed “loss of balance”) following surgery to correct spinal deformity. This may be experienced as a feeling of falling forward, a condition called sagittal decompensation (or flatback), or of falling off to one side, a condition called coronal decompensation. Flatback has been associated with Harrington rods, which were used for several decades to correct scoliosis curves and sometimes had the effect of eliminating too much of the natural “sway” in the lumbar spine.
Patients may also seek medical advice because they feel that their spinal deformity is progressing, that their clothes are fitting differently, or due to a perceived height change.
The type and site of pain the patient experiences, as well as the time when symptoms develop, all provide clues to the underlying medical issues, according to Dr. Cunningham. For example, patients who develop pseudarthrosis typically complain of activity-related pains that are “aching and dull” in character, that may be described as a severe “bruise,” and are worsened with tasks that promote movement in the area of the pseudarthrosis (bending, lifting, twisting). A patient who has severe “electrical and burning” back and leg pain on standing, or specific weakness in the leg muscles, is likely to have a neurological problem, such as a nerve root that is being compressed.
Those with back pain above or below the site of a fusion that is activity-related and classically worse at the end of the day may be experiencing muscular symptoms, as the back muscles following a fusion are required to control long segments of the spine rather than individual vertebral bones, requiring higher forces to be generated, and expected strain and fatigue symptoms if muscle power is insufficient.
Neurological pain symptoms that occur immediately after surgery raise questions about the placement of screws, or persistent pressure on a nerve root or the spinal cord. Pain that occurs some time after surgery may be a sign of degeneration/arthritis, or an infection, possibly one that started elsewhere in the body that migrated to the tissue surrounding a metal implant.
Imaging techniques used to assess patients with the symptoms listed above include the following:
Fortunately, muscle pain and fatigue that follows surgery often resolves over time and can be addressed with a range of measures including activity modification, physical therapy, moist heat, massage, and acupuncture. Chiropractic care may also be effective in limiting muscular symptoms and can be added to the above measures.
If physical therapy and other non-drug interventions are ineffective, oral medications such as non-steroidal anti-inflammatory agents (NSAIDs) or an injection with a steroid medication that will reduce inflammation may be helpful. Narcotics may also be recommended for pain relief in some situations, but are used very sparingly.
“If there is a minor problem in a post-op patient, it gets a “minor” solution,” Dr. Cunningham explains. “Patients may eventually require a revision, but they are best managed non-surgically until they need the revision done.” Dr. Cunningham notes that while arthritis is usually treated non-surgically initially, severe arthritis may also require surgery. Infections, he adds, should always be aggressively managed.
Revision surgery for spinal deformity may involve one or more procedures to address the individual patient’s symptoms and/or progression. The patient’s overall health also guides the orthopedic surgeon’s treatment recommendations. The following are just a few of the scenarios that may be considered:
Cosmetic concerns alone - if the patient is unhappy with their appearance, but has no pain or progression of the deformity - are not a common reason for revision surgery. However, when progression is demonstrated, even in the absence of pain, surgery may need to be performed to add additional fusion levels and control the progression. In other cases, the placement of additional instrumentation to support the vertebrae may address the underlying problem, and arrest the progression without additional fused levels.
While excellent results can be achieved with revision surgery, especially when patients receive care from a highly experienced multidisciplinary team, the likelihood of effective symptom control does diminish with each successive revision surgery. Moreover, revision surgeries are associated with a higher risk of complications. Patients who undergo revision surgery primarily to address deformity, and/or to correct spinal coronal/sagittal balance, will most likely see some improvement.
The degree to which pain relief can be achieved with revision surgery is somewhat harder to anticipate. Overall, Dr. Cunningham says, the best results from revision surgeries are usually seen in patients with radiculopathy or stenosis symptoms in the legs that is treated surgically with decompression surgery.
Relief of back pain symptoms varies; however, patients with more severe pain appear to show the most marked improvement.
In order to continue improving outcomes in treatment, Dr. Cunningham and his colleagues at HSS are also looking at ways to optimize bone tissue formation, remodeling, and growth. Substances called bone morphogenic proteins (BMPs) help build stronger bone and have been widely used to promote better success and stronger spinal fusions.
In addition, ensuring that patients are not Vitamin D and/or calcium deficient may improve their “bone health”, thereby strengthening their bone and improving their ability to tolerate the insertion of rods, screws, and other instrumentation, as needed.
Finally, research in the field is focusing on surgical techniques that are minimally invasive, a development that would – in some cases – allow surgeons to perform procedures using an incision of one to two inches in length instead of prior techniques that required much longer incisions. This trend towards minimally invasive techniques is expected to not only minimize soft tissue trauma, but to be better tolerated by patients and allow them to become mobile again more quickly following surgery.
"This makes good sense for patients who require short fusions,” Dr. Cunningham notes, “However, for those who require more extensive surgeries involving decompressions and fusions, traditional approaches are more appropriate.”
If you would like more information about revision spine surgery at HSS, please visit the Physician Referral Service or call 1.877.606.1555.
Summary prepared by Nancy Novick. Diagnostic imaging courtesy of the HSS Department of Radiology and Imaging.