Superior mesenteric artery syndrome following surgery for adolescent idiopathic scoliosis: a case series, review of the literature, and an algorithm for management.

Superior mesenteric artery (SMA) syndrome is a rare but potentially fatal complication following spinal fusion for scoliosis. The aims of our study were to identify clinical features and evaluate their importance in SMA syndrome following posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS) patients and to recommend a simple approach for the recognition and management of SMA syndrome. This is an IRB-approved study. Three patients in our series and 11 patients from other published case reports who underwent PSF for adolescent idiopathic scoliosis were included in our study. Patient demographics, clinical presentation, investigations, and management were recorded and analyzed. In this combined series of 14 patients (mean age 14.8 years), the main presenting clinical features included vomiting of any kind (92.9%), abdominal pain/tenderness (57.1%), abdominal distension (42.9%), bilious vomiting (35.7%), and hypoactive bowel sounds (28.6%). Most patients presented within 2 weeks of surgery (71.4%). In total, 50% of patients presented with both vomiting (of any kind) and abdominal tenderness. The number of presenting symptoms appeared to be directly related to the severity of SMA syndrome. Our second patient had intermittent vomiting on postoperative day (POD) 3, which was initially considered as insignificant; she was discharged on POD 9 and readmitted for recurrent vomiting, during which SMA syndrome was diagnosed. Our first patient presented in the classical manner. Our third patient had bilious vomiting after discharge that started on POD 13 and increased in frequency until readmission on POD 27. Vomiting and abdominal pain are nonspecific symptoms following PSF; differentiating between SMA syndrome and postoperative ileus can be challenging. The highest index of suspicion applies to patients who present within the first week with symptoms of vomiting and abdominal pain. We propose an algorithm for the management of SMA syndrome, which includes a focused clinical assessment to evaluate for intestinal obstruction, followed by an abdominal radiography and barium contrast study if clinical assessment is positive. An early referral to general surgery should be considered especially for high-risk patients (BMI<5% percentile, sagittal kyphosis). Early diagnosis of SMA syndrome allows for early intervention, reducing the likelihood of future complications and need for surgery.