Surgeons face a difficult challenge when clear evidence for the best treatment is scarce. In neurosurgery, this is a common concern, as many of the conditions neurosurgeons treat are uncommon. To formulate a treatment plan in these cases, surgeons must use their own experience and judgment, combined with careful study of the work of their colleagues. While this information hasn’t undergone the rigorous scrutiny of medical research, over time, the results of these cases can accumulate to provide robust evidence. Then a consensus can be formed about the best approach.
Neurosurgeons face this situation when caring for patients with both scoliosis (a curved spinal column) and myelomeningocele (a spinal defect allowing contents of the spinal canal to protrude through it).
Scoliosis is an abnormality characterized by curvature of the spine. Surgery to correct it is complicated, because the neurosurgeon must correct the alignment of the bony vertebral column—the structure that supports the torso and protects the spinal cord—while also protecting the spinal cord itself.
Such a surgery becomes even more complicated when there are other issues to consider, as in the case of myelomeningocele. Myelomeningocele is a spinal defect that occurs during the third week of gestation. The bones of the vertebral column do not form properly, and a sac containing meninges (the lining of the spinal column), cerebrospinal fluid and possibly nerves or spinal cord protrudes through the defect in the vertebrae.
While scoliosis can occur in any child, children with myelomeningocele have a high probability of developing scoliosis as they grow, and they may need corrective surgery. However, the approach to one aspect of this surgery in children with myelomeningocele is not universally agreed upon.
The concern is how to manage a tethered spinal cord during scoliosis surgery. A spinal cord is called tethered when it is attached in some way to the surrounding tissue. This keeps it from moving freely within the spinal column, and it is a common problem for children with myelomeningocele.
The lack of consensus on how to treat a tethered spinal cord during scoliosis surgery concerned neurosurgical resident Hannah Goldstein, M.D., so she and a group of researchers, led by senior author Richard C.E. Anderson, M.D., set out to review the work of fellow neurosurgeons to try to determine the most advantageous approach.
Neurosurgeons are of two minds about how best to manage a tethered spinal cord prior to scoliosis surgery. Some believe it should be corrected, or untethered, during a three-month window prior to the scoliosis surgery. The thinking is that untethering the cord will reduce neurological complications during scoliosis surgery. However, untethering is a surgical procedure that requires opening the dura—the membrane surrounding the spinal cord and brain that contains cerebrospinal fluid. Opening the dura introduces the risk of a central nervous system infection and other complications, so some surgeons believe the risks outweigh the benefits and therefore do not untether the spinal cord before scoliosis surgery.
But there has not been definitive research to determine which approach leads to the best results. Dr. Anderson’s team is studying the data so neurosurgeons can plan their approach based on evidence. Dr. Goldstein presented the preliminary results of their research at the AANS/CNS Joint Section on Pediatric Neurosurgery in late 2017. They are continuing to review the results of scoliosis surgery in patients with myelomeningocele from eight centers in the United States.
Preliminary results from three of the centers and 149 surgeries are promising. Patients either had untethering and scoliosis correction in a single surgery, untethering surgery within a three-month period before the scoliosis surgery or no untethering. Based on these early results, patients in all three groups retained neurological function after scoliosis surgery.
However, the two groups who received untethering surgery had an increased risk of surgical site infection, were more likely to return to the operating room within 90 days and had longer hospital stays after surgery. While this was bad news for the patients who suffered complications, the results may indicate that untethering surgery will prove unnecessary, meaning one less procedure for myelomeningocele patients in the future.
There is more work to do to complete the research protocol, but these initial results offer hope that a clear choice may emerge between the surgical approaches. This is good news for neurosurgeons, and even better news for children with myelomeningocele and their families.
To learn more about Dr. Goldstein, visit our Current Residents page here.
To learn more about Dr. Anderson, visit his bio page here.