Rates of Surgery for Spinal Deformity Increased Among Older Adults

Senior author Lionel N. Metz, MD and SpineUniverse Editorial Board member Scott A. Meyer, MD, FAAN comment

Written by Kristin Della Volpe

Rates of surgery for adult spinal deformity increased 3.4-fold among older adults between 2004 and 2011, particularly in the age groups of 65 to 69 and 70 to 74 years. Despite this increased use of surgical management, in-hospital complication rates remained stable during this period, according to a retrospective database analysis published in The Spine Journal.

“The findings suggest that surgeons are cognizant of the gravity and invasiveness of spinal deformity surgery, and have not irresponsibly expanded indications or compromised patient selection,” explained senior author Lionel N. Metz, MD, who is Assistant Professor of Orthopedic Surgery at the University of California, San Francisco. “In addition, the findings support the notion that surgery overall has become safer, and this may be due to utilization of antifibrinolytics, improved anesthetic techniques and ICU care, improvements in neuromonitoring and instrumentation techniques (eg, surgical navigation), and most significantly an increased number of spine deformity trained surgeons.”

“The authors should be commended on their work utilizing a Nationwide Inpatient Sample (NIS) database to evaluate the trajectory of deformity surgery in patients over the age of 60,” commented Scott A. Meyer, MD, FAAN, Director of Spinal Neurosurgery for the Atlantic Neuroscience Institute, Director of Spinal Deformity at Atlantic Neurosurgical Specialists, and Associate Director of Neurotrauma at Morristown Medical Center, all in Morristown, NJ.

“As the authors point out some of the increase is likely related to an increase in those trained in spinal deformity,” Dr. Meyer told SpineUniverse. “In addition, addition there is likely an impact from additional awareness in the spinal community that alignment and, in particular, sagittal alignment plays an integral role in the outcome of patients with adult spinal deformity. The increased complication rate in this patient population is important to keep in mind and presents distinct challenges when compared to the treatment of pediatric spinal disorders.”

Retrospective Database Analysis
The investigators used 2004-2011 data from the NIS to identify adults who underwent spinal fusion of 8 or more levels. They found that 29,237 adults of all ages underwent spinal deformity surgery during this period. The greatest increase in surgical rate was found among patients age 60 years and older.
The overall complication rate in all adult patients remained stable at 22.5% in 2004 and 26.7% in 2011. Rates in the subgroup of patients ≥60 years also remained stable over this period (29% and 35%, respectively), and were significantly higher than in younger patients (P<0.001). Likewise, mortality rates remained unchanged over time in the overall group and when analyzed by age subgroups.

Why Are Surgery Rates for Spinal Deformity Increasing in Older Adults?
In addition to increased safety, Dr. Metz said the increasing rate of surgical treatment for spinal deformity in older adults may stem from an improved understanding of spinal deformity for in adults.

“Historically, our understanding of spine deformity developed in the pediatric world where most of the deformity was in the coronal plane,” Dr. Metz told Spine Universe. “Only later did we understand that in adults, much of the deformity is actually in the sagittal plane. Our improved understanding of the sagittal plane as a component of spinal deformity has changed our approach to treating adults who may present with symptoms of spinal stenosis, but are revealed to have concomitant spinal deformity in addition to spinal stenosis. Improved recognition of this specific patient group may also explain the increased utilization of adult spinal deformity surgery.”

Increases Cost of Surgery Found
Mean hospital charges increased significantly in the overall group (from $171,517 to $303,479; P<0.001) and were significantly higher in patients age ≥60 years than in younger patients ($257.494 vs $208,043; P<0.001).

Potential reasons for the increased cost may include greater use of bone graft substitutes and interbody fusion.

“In addition, a big component of the increased charges may be changes in trends toward reimbursement,” Dr. Metz said. “As the percentage of charges that are reimbursed by payors decreases, hospitals may tend to increase their charges. Our paper reflects charges rather than collections on these operations.”

Dr. Metz concluded that in the future, “our next task as spine surgeons is to improve the granularity of our understanding of the surgical treatment of spine deformities in adult patients in terms of which approaches and techniques should be utilized, which levels should be addressed, where the appropriate use of costly bone graft substitutes might be, and how we might mitigate common modes of failure.”

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