AM-PAC Mobility Score <13 Predicts Development of Ileus Following Adult Spinal Deformity Surgery

Abstract

Study Design: Retrospective review. Objective: To determine whether the Activity Measure for Post-Acute Care (AM-PAC) “6-Clicks” score is associated with the development of postoperative ileus. Summary of Background Data: Adult spinal deformity (ASD) surgery has a high complication rate. One common complication is postoperative ileus, and poor postoperative mobility has been implicated as a modifiable risk factor for this condition. Methods: Eighty-five ASD surgeries in which ≥5 levels were fused were identified in a single institution database. A physical therapist/physiatrist collected patients’ daily postoperative AM-PAC scores, for which we assessed first, last, and daily changes. We used multivariable linear regression to determine the marginal effect of ileus on continuous AM-PAC scores; threshold linear regression with Bayesian information criterion to identify a threshold AM-PAC score associated with ileus; and multivariable logistic regression to determine the utility of the score thresholds when controlling for confounding variables. Results: Ten of 85 patients (12%) developed ileus. The mean day of developing ileus was postoperative day 3.3±2.35. The mean first and last AM-PAC scores were 16 and 18, respectively. On bivariate analysis, the mean first AM-PAC score was lower in patients with ileus than in those without (13 vs. 16; P<0.01). Ileus was associated with a first AM-PAC score of 3 points lower (Coef. −2.96; P<0.01) than that of patients without ileus. Patients with an AM-PAC score<13 had 8 times greater odds of developing ileus (P=0.023). Neither the last AM-PAC score nor the daily change in AM-PAC score was associated with ileus. Conclusions: In our institutional cohort, a first AM-PAC score of <13, corresponding to an inability to walk or stand for more than 1 minute, was associated with the development of ileus. Early identification of patients who cannot walk or stand after surgery can help determine which patients would benefit from prophylactic management. Level of Evidence: Level—III.