Fred Sweet, MD, co-founder of Rockford (Ill.) Spine Center developed a transforaminal anterior release technique to correct severe spinal deformities in 2005.
Over the past eight years, Dr. Sweet and his partners have performed the technique on more than 70 patients.
"Traditionally, people with fixed sagittal imbalance and segmental kyphosis are treated with three column osteotomies," says Dr. Sweet. "Not only are these procedures technically demanding but there is a high blood loss and significant neurologic injury rate. I wanted to achieve this same correction without the blood loss and reduced neurologic risk. That is how I came up with this procedure."
Dr. Sweet has shared his results with peers in the medical field and presented a paper on the TFAR procedure at the International Meeting on Advanced Spine Techniques in July. Here he discusses the procedure and where treatment for spinal deformity is headed in the future.
Q: Where does this procedure fit with the current treatment for spinal deformities? What types of patients stand to benefit most?
Dr. Fred Sweet: This is an extension of the TLIF or PLIF. I remove the facet joint, perform a discectomy and prepare the disc space for bone graft and a cage. After the discectomy I remove and resect the anterior annulus through the unilateral annulus from the back side. I resect the anterior annulus through the TLIF approach so I have a completely mobile spine at the disc level. However, there is not much bleeding because there is no cutting through the bone or manipulating the epidurals beyond normal TLIF approach.
Most of the patients with deformities we treat with the TFAR procedure are elderly and have several other medical problems. Many are not good candidates for the bigger three column osteotomies because of the associated blood loss.
There are additional risks with the traditional osteotomy procedure that can produce poor outcomes. Often it is difficult to modify or adjust the degree of correction after you perform the osteotomy because you have to close it down. In the TFAR we do an opening wedge correction via situ rod contouring. We can dial in as much or as little correction as we need for each particular patient.
This TFAR is used to correct sagittal imbalance through nonfused disc spaces. A vertebral body reduction such as high-grade spondylolisthesis or segmental kyphosis can be performed anywhere in the thoracolumbar spine including the lumbosacral junction. To that extent, it is very useful for high-grade spondylolisthesis as well as fixed sagittal imbalance.
Q: Beyond less blood loss, what other benefits are there for performing the TFAR procedure?
FS: Because this is an opening wedge correction, we are not narrowing the spinal canal and as such, we have not seen the significant neurologic complication rate as we do with a pedicle subtraction osteotomy. You can extend these procedures to the elderly and those who have medical comorbidities. Not one of our patients required ICU stay after surgery as the blood loss was very low for the magnitude of the surgery.
I have also found this procedure is very helpful for people with segmental kyphosis. They do not need a pedicle subtraction osteotomy but they need more than in situ correction. The TFAR procedure fills this gap.
Q: Does it require special equipment or can surgeons learn the technique using their preferred devices?
FS: When I first started performing this procedure, I had specialized cages that were large and it was technically difficult placing them. I modified the procedure so it is done with standard TLIF equipment and cages. The good thing is that a surgeon who has extensive experience with TLIF can learn this technique very easily. However, there are a few things surgeons must watch out for, such as utilization of a stabilizing rod when doing a release; the spine can become very unstable and produce neurologic injury.
Q: Are there any other challenges when performing the TFAR technique?
FS: There is another caveat: when resecting the annulus, be careful not to injure the vena cava and aorta. That is the reason why many surgeons will be slow to adopt the procedure because they will have concern over vascular injury. In the mid 1950s and 1960s, there were case reports of patients who underwent an old technique for spine surgery that incurred vascular injury. Some of those patients received radiation treatment as well, which made them more receptive to injury.
We are still performing opening wedge correction with monitoring techniques and there have not been reports of significant aortic or vascular injuries. Patients done carefully with modern instrumentation, vascular injury rate is low and very acceptable.
Q: You and your partners have been doing this for several years. How many others out there are performing similar types of procedures?
FS: There are a few people starting to perform this technique. I've discussed cases with Lawrence Lenke, MD, at the University of Washington and a few other surgeons. Otherwise not many surgeons are doing it because I think many are unaware of the procedure. I have been working on an article for publication and presented at the IMAST meeting this year to raise awareness for the technique.
Q: Do you think this procedure will become more the standard of care in the future?
FS: I think the pedicle subtraction osteotomy will be the mainstay because most people are comfortable with that and they are able to work around the blood loss issues. The TFAR is a way to help people who are sicker undergo surgical correction. However, in our practice, it's replaced the pedicle subtraction osteotomy.
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