Reliability of semi-automated spinal measurement software

In the treatment of patients with adult spinal deformity, analysis of spinopelvic balance is essential in clinical assessment and surgical planning. There is currently no gold standard for measurement, whether done by hand or with digital software. New semi-automated software exists that purports to increase efficiency, but its reliability is unknown in the literature.

Full spine X-rays were retrospectively reviewed from 25 adult patients seen between 2014 and 2017. Patients were included if they had > 5 cm of sagittal imbalance and radiographs of sufficient quality to perform balance measurements, without prior surgical spinal fusion and/or instrumentation. Spinopelvic parameters were measured in two radiographic programs: one with basic, non-spine-specific measurement tools (eUnity, Client Outlook, Waterloo, Canada); and a second with spine-specific semi-automated measurement tools (Sectra, Sectra AB, Linköping, Sweden). Balance parameters included SVA, PI, PT, and LL. Data were compared by examining inter-rater and inter-program reliability using interclass correlation coefficient (ICC).

The subjects' mean age was 67.9 ± 13.8 years old, and 32% were male. The inter-program reliability was strong, with ICC values greater than 0.91 for each parameter. Similarly, there was strong inter-observer reliability with ICC values greater than 0.88. These results persisted on delayed repeat measurement (p < 0.001 for all measurements).

There is excellent inter-observer and inter-program reliability between the basic PACS and semi-automated programs. These data demonstrate that the purported efficiency of semi-automated measurement programs does not come at the cost of measurement reliability.