Nonoperative treatment of adult spinal deformity does not improve disease state or physical function

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A study presented at the 29th annual meeting of the North American Spine Society (NASS) suggests that operative treatment for adult spinal deformity (ASD) improves both disease state and physical function regardless of patient age and deformity type, while nonoperative treatment has no such impact.

Shay Bess and others compared baseline and two-year follow-up SF-36 health survey scores of ASD patients to evaluate the ability of operative or nonoperative treatment to “1) restore ASD patients to normative physical function levels and 2) identify disease state correlates for different deformity types and the ability of treatment to improve health status.” The authors also compared SF-36 scores against the baseline US generational norm to better understand the impact and severity of each deformity type.

The analysis was taken from the multicentre, prospective study with consecutive case series involving 302 patients. The patients involved were over the age of 18, had a diagnosed case of ASD (minimum of one of: adult scoliosis >20 degrees, sagittal vertical axis >5cm, pelvic tilt >25 degrees or thoracic kyphosis >60 degrees) and had undergone no prior spinal surgery. The patients were then split into operative and nonoperative groups to examine the impacts of both types of treatment. The average age of the patients was 51.6 years.

The study’s results showed that all ASD patients who received operative treatment saw an improvement in their SF-36 physical component scores after two years (8.9 points), remaining below 25th percentile US norms. On the other hand, nonoperative treatment was shown to have no effect on patients’ SF-36 scores. Importantly, as Bess explains: “though the operative group improves, they do not quite get back to the generational norm.”

The authors’ generational analysis showed that operative treatment resulted in an improved state of health across all age groups, with younger generations even reaching US norms. Nonoperative treatment resulted in worsening health across all ages. Operative treatment had the most significant effect on SF-36 scores in the 30-40 (seven points) and 70-80 (13 points) age ranges.

For all deformity types, operative treatment resulted in improved physical component scores, with the most successfully treated deformities being lumbar scoliosis (improvement of nine points) and sagittal vertical axis >10cm (improvement of nine points). Despite improved physical function, operative patients’ SF-36 scores remained below US norms. Nonoperative treatment failed to improve SF-36 scores for any deformity type, and in fact caused a worsening of sagittal vertical axis >10cm scores (decreased by three points).

Bess and colleagues comment that “Operative treatment provides improvement for all deformity types whereas nonoperative treatment does not improve disease state regardless of deformity of type.” Bess concludes by suggesting that “this information is key in counselling patients in terms of where they are going to be post-operatively from a physical function standpoint.”