Orthopedic spine surgeons at NewYork-Presbyterian/
- Provides an intraoperative target
- Accounts for lower extremity factors (leg length discrepancy and pelvic obliquity) using EOS imaging
A recent study on this method shows that we may be able to predict postoperative coronal alignment more accurately up to two-year follow up, according to Nathan Lee, MD, an adult and pediatric comprehensive spine fellow at NewYork-Presbyterian/
Dr. Joseph Lombardi
Dr. Zeeshan Sardar
Dr. Nathan Lee
One of the goals of adult spinal deformity surgery is to align the spine in the coronal and sagittal planes. Failure to optimize alignment has been associated with worse patient-reported outcomes and greater surgical complications. Recent studies have shown that the incidence of postoperative coronal malalignment may be as high as 20-30%.
The Missing Piece
Many cases of postoperative coronal malalignment are iatrogenic in nature and may be preventable. Classifications to address coronal deformity have been previously proposed and have been instrumental in our understanding of the various subtypes of coronal deformity; however, they rely on upright preoperative radiographs and do not assess for pelvic and lower extremity factors. Dr. Lee says.
Our research demonstrates the importance of assessing the entire patient from skull to feet in adult spinal deformity. In comparison to prior literature, our recent study takes advantage of EOS technology to better assist surgeons in optimizing coronal alignment for these patients.
— Dr. Nathan Lee
There has been a resurgence of interest in appropriately addressing coronal alignment in adult spinal deformity surgery. In the last few years, several studies led by Lawrence G. Lenke, MD, Co-Director and Surgeon-in-Chief at Och Spine at NewYork-Presbyterian, and Chief of Spinal Deformity Surgery in the Department of Orthopedic Surgery at NewYork-Presbyterian/
The Critical Role of EOS Imaging
NewYork-Presbyterian/
“One of the unique things about NewYork-Presbyterian/
Preop and postop EOS films of patient who underwent adult spinal deformity surgery. Preop films show coronal malalignment with lower extremity compensation. Postop films demonstrate well-aligned spine in sagittal and coronal planes with resolution of lower extremity compensation.
Simple trigonometry is used to create new targets accounting for leg extremity factors to address the malalignment. “By accounting for lower extremity factors with our novel method, our study found that we may be able to reduce the margin for error in predicting alignment to less than a centimeter,” says Dr. Lee.
Study Details
The study included 108 patients who underwent posterior spinal fusion of at least six or more levels, including pelvic fixation, and had a minimum of two-year follow-up in the study. All patients had coronal malalignment prior to surgery.
The study is the first to quantify lower-extremity compensation in the coronal plane for adult spinal deformity surgery. But it’s just the first of the team’s efforts to clarify the role of lower-extremity factors.
We are encouraged that this method can work so well in this complex population, because there are so many variables that may alter alignment. Using trigonometry, we attempted to simplify the many factors into a classification which may better inform surgeons how to account for lower extremity factors and optimize coronal alignment.
— Dr. Nathan Lee
“This study is the first of many papers that we're planning to publish [on this new method],” says Dr. Lee. “We are doing follow-up research to further study the association between this method and patient-reported outcomes, complications, and reoperations.
In subsequent research, the team has reported that post-surgery changes in the knees and hips to compensate for patients’ coronal malalignment are an independent risk factor for worse patient-reported outcomes two years out, another first. They have also shown that correcting coronal malalignment intraoperatively may reduce the lower extremity compensation that can result from spinal deformity surgery.