BMIBody mass index FAQ Functional Assessment Questionnaire SDR Selective dorsal rhizotomy TDC Typically developing children AIM The aim of this study was to retrospectively analyze changes in age-and sex-adjusted body mass index (BMI) in ambulatory children with cerebral palsy (CP) who underwent selective dorsal rhizotomy (SDR).METHOD Raw BMI, age-and sex-adjusted BMI z-scores, weight classification status, energy expenditure, and ambulation function were calculated before and after SDR at multiple post-SDR time points: 6 to <24 months, 24 to <48 months, 48 to <72, and 72 to <96 months. Linear mixed models were used to analyze changes in raw BMI, BMI z-scores, energy expenditure, and ambulation function.RESULTS Pre-and post-surgical data were available for 363 children diagnosed with CP who underwent SDR (219 males, 144 females; mean age 6y [SD 2y 1mo]; mean BMI z-score 0.09 [SD 1.21]). Data from additional post-surgical time points were collected on subsamples. Although raw BMI significantly increased (p<0.01), these increases were consistent with anticipated growth. BMI z-scores did not significantly change over the 10-year study period.INTERPRETATION Concerns of unhealthy weight gain following SDR are not supported by this study. Further work examining possible risk factors for BMI increase following SDR, as well as examining disparities in existing criteria for patient selection, is merited.Cerebral palsy (CP) affects nearly 3.1 per 1000 children in the USA. 1 Four out of five of these children have a component of spasticity, characterized by increased muscle tone. 2 This increase in tone often makes movement challenging and contributes to increased metabolic demand, more than threefold higher than that of typically developing children (TDC). 3 There are several treatments aimed at reducing spasticity (e.g. intrathecal baclofen pump and selective dorsal rhizotomy [SDR]). Changes in spasticity likely have an effect on the energy needs of an individual. If these changes are not counterbalanced by changes in diet or activity, unhealthy weight gain may follow.Unhealthy changes in weight are a concern across the population. The most common categories for weight status are underweight, healthy, overweight, and obese (body mass index [BMI] <5th, 5th to <85th, 85th to <95th, and ≥95th centiles respectively). 4 Results from the most recent National Health and Nutrition Examination Survey estimate that 15% of 6-to 19-year-olds are overweight and 18% are obese.5 Children with CP are often thought to be smaller than TDC of the same age; 6-8 however, there is evidence that unhealthy weight gain occurs in children with CP. The prevalence of overweight and obese children with disabilities, including those with CP, has been shown to be significantly higher than in non-disabled children.9,10 A longitudinal trend of increasing obesity prevalence has been shown in CP, and is on par with the rise seen in all children and adolescents. 11 These high rates of obesity are problematical for several reasons. Obesity is linked with m...