Why Does Spine Surgery Sometimes Fail?
Have you ever had a friend or loved one tell you “I’ve had 7 spine surgeries, and I’m worse off now than I was before surgery!” How can this possibly happen? Surgery is supposed to relieve suffering, not worsen it! Every week in my clinic I see patients who are very tentative about spine surgery for this very reason. A clear understanding of why spine surgeries fail often sets their mind at ease.
If a spine surgery fails to relieve your symptoms, or the same or different symptoms recur after spine surgery, then you have experienced “failed spine surgery.” There is a myriad of reasons why a spine surgery may fail. Ultimately, the patient is the final judge of whether or not a spine surgery was successful, as the ultimate goal is to relieve the patient’s symptoms, not make the patient’s X ray or CT scan look better. There are unfortunately many surgeons who “treat the images, not the patient” and fail to address the patient’s primary complaint in favor of correcting pathology seen on an MRI scan (which may, or may not be the cause of the complaint!)
A common reason that spine surgeries fail is “pseudoarthrosis.” The technical term for spinal fusion is “arthrodesis.” This means that the surgeon takes a vertebral joint segment, scrapes the disc and cartilage out of the space until only bony endplate is present, and places bone growing material in that space to encourage the patient to grow their own bone across that space, thereby creating a “living bridge” across that joint space that does not move (much like a broken bone that is casted and heals, although this process is not exactly the same.) If this process fails, if the patient’s bone does not grow across this space, then the spine becomes very unstable. This is called “pseudoarthrosis”. There is no disc to support motion at this spinal segment, and it is only held in space by the screws and rods, which are very strong but not perfect. In this case the screws are exposed to tremendous forces, and they are not designed to resist these forces indefinitely. The screws and rods over time will either reach their strain limit and break, or will loosen and pull out of the bone. This results in severe pain in the patient. The surgeon must go back in and remove the broken hardware, replacing it with new hardware, and attempt to get the segment to fuse. Smoking cigarettes (or using nicotine in general) is one of the most common ways that pseudoarthrosis occurs, as nicotine prevents wound healing and bone growth. Smoking is such a well known cause of pseudoarthrosis that insurance companies typically will not approve a spinal fusion surgery unless the patient is totally smoke free. This is why I typically require all of my patients to be totally smoke free for elective spinal fusion cases.
Another common reason why spine surgeries fail is a rather insidious one. The lumbar spine is in a unique location with regards to our total balance as bipedal beings. The normal curvature of the lumbar spine (typically “lordotic” in nature, or curved outwards toward the belly) allows us to balance our heads and shoulders over our pelvis, in what is called the “cone of economy.” If we pitch forward and our heads extend forward past this cone of economy due to loss of lumbar lordosis, then our pelvis and legs have to work overtime to bring our head back over our pelvis. This results in significant back and leg pain over a long period of time. If this goes unrecognized by the spine surgeon, it can result in the stories you may have heard about patients having multiple spinal fusions and no relief in their pain. Attempting to try and fix this problem requires a recognition of the problem using a long, standing Xray and a strategy to re-align the spine. The surgical strategy may be more complex than other surgeries on the spine, but there is always hope in these cases.