A spine surgery can look successful by nearly every conventional measure. The patient leaves the hospital, avoids major complications and has reassuring postoperative imaging. But none of that necessarily answers the question that matters most: Is the patient actually functioning better?
For Corinna Zygourakis, MD, a neurosurgeon and associate professor at Stanford (Calif.) University School of Medicine, that disconnect exposes a blind spot in how spine surgery outcomes are evaluated.
Surgeons have long relied on patient-reported outcomes, hospital length of stay, discharge destinations and complication rates to assess surgical success. Yet those measures, while important, do not always capture what patients can do once they return to everyday life.
Dr. Zygourakis believes the next advance in spine surgery may come from measuring recovery differently.
“We really need to move towards integrating objective functional data on our patients,” she told Becker’s.
Through her research using Apple Watches to track patients before and after spine surgery, she is investigating whether objective activity measurements can complement traditional assessments and offer a more complete picture of recovery.
The implications extend beyond wearable technology. They raise a larger question about what surgeons, hospitals and researchers should consider evidence of a successful operation.
What traditional measures miss
Patient-reported outcome measures, or PROMs, remain the standard for evaluating pain, disability and quality of life after spine surgery. But they rely on patients describing their experiences rather than directly measuring physical function.
Dr. Zygourakis sees an opportunity to supplement those assessments with three dimensions of objective recovery: daily activity, functional capacity and gait quality.
Consumer wearables can capture step counts, standing time and exercise duration. Functional tests measure abilities such as walking a certain distance within six minutes, while gait analysis can assess balance, stride and symmetry.
Each provides information that conventional questionnaires may miss.
The distinction matters because how patients feel and how they function do not always move together. Earlier studies have found modest or no correlations between wearable activity measurements and patient-reported outcomes, suggesting the two approaches may capture different aspects of recovery.
“I don’t think that objective data will replace the PROMs, but it will be complementary to them,” she said. For Dr. Zygourakis, the goal is not to replace patients’ perspectives with numbers. It is to understand whether those numbers can reveal something important that traditional assessments overlook.
The Apple Watch experiment
That question led Dr. Zygourakis to launch SpineTrack, a randomized clinical trial using Apple Watches to monitor patients undergoing elective spine surgery. The study collects activity data beginning two to six weeks before surgery and continuing for a year afterward, allowing researchers to examine how movement changes throughout recovery.
Earlier research had produced mixed findings. In one small Stanford pilot study, patients’ daily step counts declined immediately after surgery, then returned to baseline without consistently improving beyond it. Researchers also found no clear correlation between step counts and patient-reported outcomes.
SpineTrack was designed to investigate those relationships more extensively, including whether measures such as daily steps, exercise time, standing time or heart rate provide meaningful information about recovery.
One early challenge was determining what normal activity looks like for patients with spinal disease. A step count alone offers limited insight without accounting for factors such as age, sex and the patient’s underlying condition.
Using preoperative data and a larger external Apple Watch dataset, Dr. Zygourakis and her colleagues developed age- and sex-adjusted reference scores to characterize activity impairment among patients with cervical and lumbar spine conditions.
The team has also studied how many consecutive days of wearable data are needed to reliably evaluate activity. Those preliminary findings have been published. Additional analyses examining the trial’s full year of postoperative follow-up have been submitted for publication.
The broader ambition is to develop outcome measures that combine patients’ reported experiences with objective evidence of their physical function.
The challenge isn’t collecting data
Consumer wearables can generate enormous amounts of information. Determining what to do with it is considerably harder. Dr. Zygourakis cautions that researchers have not yet established that wearable data provides a better assessment of recovery than existing patient-reported measures.
Before the technology becomes part of routine spine care, researchers must demonstrate that the information is clinically meaningful and can guide decisions that improve outcomes. For example, could changes in activity help identify patients who would benefit from additional physical therapy or closer postoperative monitoring?
Those possibilities remain to be established. “We really haven’t proven that this objective data is necessarily better than the PROMs,” she said.
Integrating wearable information into clinical workflows presents another obstacle. Data must be collected consistently, interpreted appropriately and incorporated into electronic medical records without overwhelming clinicians.
Dr. Zygourakis believes progress will require collaboration across institutions and datasets involving thousands of patients. She points to continuous glucose monitoring in diabetes care as an example of how large volumes of patient-generated data can eventually become useful in routine treatment.
Over the next five to 10 years, she expects research and technological advances to move objective functional monitoring closer to everyday spine care. She also sees a possibility that insurers could eventually seek objective evidence of recovery after expensive spine procedures, although such requirements remain speculative.
Redefining a successful operation
For Dr. Zygourakis, the bigger question is how spine surgery defines success.
Traditional measures such as hospital length of stay, discharge destination and complication rates do not always reflect surgical quality. Whether a patient returns home or enters rehabilitation may depend more on age, available support and baseline health than the operation itself. Even complications vary widely in severity.
Imaging has similar limitations. “Perfect imaging does not always equate to a happy patient,” she said.
Dr. Zygourakis envisions a future in which objective functional data, including wearable measurements, complement traditional outcomes and become part of national registries such as the American Spine Registry.
Getting there will require larger studies and collaboration across health systems, researchers and industry. Wearables remain primarily a research tool, with their clinical value still being established.
But the goal is clear: Move beyond measuring how surgery went to understanding how patients live afterward.
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