Hypotension during adult spinal deformity surgery: a risk factor for postoperative complications?

Abstract

Objective: Intraoperative hypotension is common during adult spinal deformity (ASD) surgery, occurring because of blood loss and sometimes requested by surgeons during exposure, but its impact on postoperative complications is unclear. In patients who underwent ASD surgery, the authors sought to evaluate the relationships between intraoperative hypotension and 1) medical complications, 2) length of hospital stay (LOS), 3) discharge disposition, or 4) reoperation.

Methods: The authors performed a retrospective cohort study of patients who underwent ASD surgery from 2009 to 2023 and had a 2-year follow-up. The primary exposure variable was intraoperative hypotension, defined as mean arterial pressure (MAP) < 65 mm Hg for at least 30 minutes. The primary outcomes were 1) complications, 2) reoperation, 3) LOS, and 4) discharge disposition. Multivariable logistic regression controlled for age, sex, BMI, comorbidities, and operative time.

Results: Among 277 patients who underwent ASD surgery, 70 (25%) were males and the mean age was 62.5 ± 17.5 years. Intraoperative hypotension was observed in 122 patients (44%) for a mean duration of 45.4 ± 47.6 minutes, with most of these patients (66%) having hypotension in the second half of surgery. Patients with intraoperative hypotension had a greater incidence of postoperative medical complications (28% vs 17%, p = 0.026), including pulmonary complications (12% vs 3%, p = 0.003), yet no difference was seen in reoperation rates (39% vs 32%, p = 0.278). Neither was there a difference in LOS (7 ± 7 vs 7 ± 12 days, respectively, p = 0.814) or home discharge (p = 0.097) between groups. On multivariable logistic regression, intraoperative hypotension was an independent risk factor for any medical complications (OR 2.0, 95% CI 1.0-3.9, p = 0.047), especially pulmonary complications (OR 5.1, 95% CI 1.5-17.0, p = 0.008).

Conclusions: In ASD surgery, intraoperative hypotension (MAP < 65 mm Hg for ≥ 30 minutes) was independently associated with medical complications, particularly pulmonary complications. These findings highlight the importance of avoiding prolonged hypotension in ASD surgery.