Superior mesenteric artery syndrome in scoliosis surgery: weight percentile for height as an indicator of risk.

A retrospective analysis of charts identified cases of superior mesenteric artery (SMA) syndrome occurring after scoliosis surgery over a 23-year period. Despite numerous reports on this potentially fatal complication of scoliosis surgery, no method exists to stratify patients for risk of developing disease after spine surgery. A study of charts was performed to identify all cases of SMA syndrome occurring after scoliosis surgery from 1972 to 1995. An upper gastrointestinal study with findings specific for the syndrome was requisite for inclusion. Patients' weight and height at the time of diagnosis of SMA syndrome were recorded. Based on standard national data tables, a percentile for weight, percentile for height, and a weight percentile for height were derived for each patient. The syndrome occurred after posterior spinal fusion in six patients (three boys, three girls). The average weight percentile for height, available in five of the six patients, was 3%, significantly different from both age-matched controls in the general population and from age-matched controls undergoing posterior spinal fusion for adolescent idiopathic scoliosis. This study, the largest reported from a single institution, suggests that a weight percentile for height of 5% is the degree of asthenia that allows compromise of the duodenum. The percentile identifies patients at risk for SMA syndrome for the purposes of increasing postoperative vigilance for gastrointestinal complaints, decreasing the threshold for diagnostic workup, and guiding perioperative dietary supplementation.