Ben Moore: Isthmic Spondylolisthesis

Michelle Moore: Degenerative Spondylolisthesis

Max W. Cohen, MD, FAAOS, treated a mother and son, Michelle and Ben Moore, who had different forms of the same condition, spondylolisthesis, which is a slippage of one vertebra onto the other. Spondylolisthesis literally means “vertebra” (spondylo) “to slip” (listhesis) in its Greek origins.

Ben had isthmic spondylolisthesis. Commonly found in adolescent athletes (such as gymnasts, football players and divers), this type of spondylolisthesis occurs after a stress fracture in the area of the vertebra called the pars. The fracture itself is called spondylolysis. Over time, the fractured bone can shift forward. When that happens, it is called spondylolisthesis – and it may or may not cause symptoms.

“There’s a genetic component to this type of spondylolisthesis,” Dr. Cohen says. “The thinnest part of the vertebra is what breaks. That allows the whole vertebral body to shift forward. In most cases, surgery is not necessary for teens with spondylolisthesis.”

“We can treat most cases of spondylolisthesis in kids with a back brace and physical therapy,” Dr. Cohen says. “However, there are some cases where the slippage progresses to the point where surgery is needed. That’s what happened to Ben.”

Ben’s mother, Michelle, had degenerative spondylolisthesis.

“Degenerative spondylolisthesis occurs more in the 40s and 50s age groups,” Dr. Cohen says. “It usually occurs in women, and we’re not sure why that is. It could have something to do with hormonal differences in ligaments.”

In both isthmic and degenerative spondylolisthesis, a shifting of the bone causes the problem.

“But in isthmic (the kind Ben had) the shifting is due to a crack in the pars, so only the front of the bone shifts forward,” says Dr. Cohen. “In degenerative spondylolisthesis, there’s an instability of the entire segment due to degeneration of the joint. The joint is arthritic and incompetent, and the whole bone, front and back, shifts forward.”

“Degenerative spondylolisthesis often occurs along with spinal stenosis, a narrowing of the spinal canal,” Dr. Cohen says.

Spinal fusion is often used to treat both types of spondylolisthesis. Spinal fusion is a complex procedure performed under anesthesia, in which the surgeon joins segments of the spine together. Bone grafts are laid over the vertebra, with splints fashioned from rods, screws and other instrumentation used to hold the grafts in place until they heal. Dr. Cohen has extensive experience with the procedure.

“There are certain disorders of the spine that do well with fusion,” he says. “Spondylolisthesis is one of those.”

Rick Chaney: Minimally Invasive Lumbar Fusion (also called Minimal Incision Lumbar Fusion)

In the Q and A below, Max W. Cohen, MD, FAAOS, discusses this procedure and how it can help patients.

Q: Your patient Rick Chaney was among the first in the county to have a procedure called a minimally invasive posterior lumbar fusion (or minimal incision spine surgery). What is this?

A: A minimally invasive posterior lumbar fusion is a surgical procedure that allows for a shorter hospital stay, less post-operative pain, a quicker recovery, a smaller risk of infection and a faster return to work than a traditional spinal fusion. It also avoids damage to the paraspinal muscles, which are important for the back to function normally.

Q: I understand you were one of the first surgeons in the country to begin performing this procedure.

A: Yes, I was one of the first to actually do this type of fusion, and I taught other surgeons how to do it from about 2005 through 2008. Today, I don’t do as much training because the procedure is much more common.

Q: What do you do differently with this surgery than with a traditional lumbar fusion?

A: The difference is, with traditional back surgery, we have to cut through muscle as we make an incision in the middle of the spine area. With minimally invasive spine surgery, we make small incisions off to the side of the spine, and then we work in line with the muscle fibers, so we sort of spread the muscle fibers but don’t cut them.

Q: Why is it better if you can avoid cutting the muscle?

A: In the early days of spine surgery, we didn’t worry about the muscle. We just did our work on the spine and then we wondered why many people still had back pain. We know now from MRI scans after surgery that muscle that has been cut develops scar tissue. That’s not good. The muscle is no longer functioning, so that can lead to more pain. We now recognize that the muscle itself is important in the patient’s recovery. So now we pay more attention to preserving the muscle – not only fixing the problem underneath the muscle, but trying to preserve the muscle itself so it is healthy when we are done.

Q: Have studies proven better results long-term for patients who have the minimally invasive procedure?

A: Studies have shown that at least initially patients do better. There’s less blood loss and the hospital stay is shorter. It’s much harder to prove whether the long-term results are better, because there are so many variables between patients, and it’s difficult to prove that patients had comparable, equally bad problems to start with.

Q: Can all fusion patients benefit from this type of surgery?

A: No. It depends on the patient’s individual case. Patients who are having a single-level fusion (where we are fusing only two vertebrae) are the best candidates for the minimally invasive lumbar fusion. However, all patients are benefiting from our increased understanding of the muscle’s importance in recovery. Even in traditional fusions, we are now using techniques that allow us to minimize muscle trauma.

Joyce Cantrell: Adult Scoliosis and Degenerative Disc Disease

Max W. Cohen, MD, FAAOS, who corrected Joyce Cantrell’s curvature in spinal fusion surgery, notes that adult scoliosis is most common in women – and difficult for many surgeons to treat.

“Most doctors won’t even attempt to tackle a case like this – scoliosis in an adult, an older adult,” Dr. Cohen says. “If the surgeons do something, they often sort of ignore the scoliosis and treat it like a degenerative disc.”

“That is because the great majority of neurosurgeons and orthopedic surgeons were trained to treat only degenerative conditions of the spine,” he says.

“That’s one category of spine surgery,” Dr. Cohen says. “The other category is deformity surgery. That’s where there is some sort of twist of the spine or some sort of curvature. That’s a whole other realm.”

“In a case like Joyce’s, where there’s a deformity – adult scoliosis, or curvature of the spine – in addition to degenerative disc disease, it’s critical to treat both conditions.” Dr. Cohen says. “Many surgeons do not do that.”

“Since very few surgeons have training in deformity surgery, they only see and treat the degenerative problem,” Dr. Cohen Says. “But when you have a degenerative problem superimposed into a scoliosis, ignoring the scoliosis often leads to early failure of the surgery – or it just doesn’t work.”

Dr. Cohen is the only doctor in the Triad with double fellowship training in both types of surgery. He completed a fellowship in spine and scoliosis surgery at Cornell University’s prestigious Hospital for Special Surgery, the top-ranked orthopaedics hospital in the U.S.

The approach to surgery at Spine & Scoliosis Specialists reflects Dr. Cohen’s dual training.

“What we do differently here is we look at the spinal alignment, not just each individual segment, but the whole global alignment and how it affects the patient,” says Dr. Cohen. “When the patient has a disc problem along with scoliosis (an abnormal sideways curvature) or kyphosis (rounding of the back), we feel that you need to address the entire spine – correcting the abnormal alignment in addition to the degenerative disc problem.”

To help Joyce with her scoliosis and degenerative disc disease, Dr. Cohen used instrumentation to fuse her spine from T4 to L4. Because her spinal column had become stiff, Dr. Cohen also performed osteotomies to loosen it up so additional straightening could be obtained.

“And she did very well with that,” he says. “That addressed her scoliosis and the arthritis that had developed within the scoliosis, and it helped her pain.”

Within a couple of years of the surgery, she developed disc degeneration lower on the spine – and had a second surgery for that.

“I was trying originally to save two discs, but with time she had worn those two discs out,” Dr. Cohen says. “So ultimately, we had to extend the fusion down two more. Using innovative techniques, we were able to remove the bottom of the scoliosis surgery and then extend the surgery down across the last two discs in the same kind of fusion we used before. That seems to have been very helpful for her and now she is doing very well.”

He notes that one reason many surgeons don’t perform adult scoliosis surgery is because it is complex surgery that can be especially time-consuming in older patients, with the risk of complications.

“This is surgery that you need to be able to do quickly but precisely,” he says. “We use muscle sparing and minimally invasive techniques wherever we can to minimize surgery time and to improve the recovery. We do so many of these surgeries and have become so adept at it, that we can do them in older adults with successful outcomes and without complications.”