Etiology and Risk Factors for Acute Pancreatitis after Scoliosis Surgery

Introduction: Acute pancreatitis (AP) complicates the postoperative course after posterior spinal fusion in up to 18% of children and adolescents. Though mostly mild, significant morbidity and occasional mortality from hemorrhagic pancreatitis has been reported. The mechanism is unknown, though AP is associated with prolonged aortic clamping in cardiac bypass surgery.

Methods: In a prospective study, we enrolled 74 patients undergoing posterior spinal fusion for scoliosis, both neuromuscular and idiopathic. Cytokines IL-6, IL-8 and TNF were obtained preoperatively, immediately postoperatively and day 1 post operatively. Intraoperative blood loss and duration of hypotension were recorded. Gastric tonometry was used to obtain gastric mucosal pCO2 at 30 minute intervals, and the gap above end tidal pCO2 was used to estimate duration of splanchnic hypoperfusion intraoperatively (greater or less than 60 minutes). Acute pancreatitis was diagnosed based on a three-fold increase in amylase, elevation of lipase, and clinical symptoms. The length of hospital stay (LOS) and complications were recorded.

Results: 11/74 patients developed acute pancreatitis postoperative days 3 to 5. Neuromuscular scoliosis was the diagnosis in all of the eleven patients with AP, and 10/11 had cerebral palsy. No patients with idiopathic scoliosis developed AP. The LOS in days was significantly longer in the AP group (25 +/- 15 vs. control 8+/-9, P<0 .05), as was the risk of bacteremia and/or line sepsis (4/11 vs. 2/63, P<0.05). Intraoperative blood loss in mls also increased AP group 3720 +/- 2771 control 1637 1092, P<0.05), though no significant systemic hypotension noted. The immediate post-operative TNF levels, pg/ml were higher (8.2 4.2 +/ - 3.5, and similar differences seen IL-6 IL-8.. Gastric tonometry completed 12 cases 2/12 developed acute pancreatitis. duration splanchnic hypoperfusion greater than 60 minutes both pancreatitis, 4/10 controls (P< 0.05).

Conclusions: Posterior spinal fusion is associated with prolonged splanchnic hypoperfusion, and those patients undergoing PSF for neuromuscular scoliosis appear to be most susceptible. The risk of developing AP after PSF is associated with increased intraoperative blood loss, elevated TNF, IL-6, and IL-8 levels, and greater than 60-minute splanchnic hypoperfusion. The cytokine profile in the immediate postoperative period is similar to that seen after ischemia/reperfusion from prolonged aortic clamping, and is predictive of subsequent AP. If confirmed early, intervention may be possible for those at risk.