Superior mesenteric artery (SMA) syndrome causes duodenal obstruction between the SMA and aorta, which culminates into bowel obstruction. Meanwhile, nutcracker syndrome (NCS) involves left renal vein compression between the aorta and SMA, categorized by the compression site. We present a 15-year-old female with no prior medical or surgical history who displayed early signs of the rarely coexisting SMA and nutcracker phenomena, which were managed symptomatically along with nutritional support to reach her optimal body mass index.

OBJECTIVE: Nutcracker syndrome (NCS) can be caused by narrowness of the superior mesenteric artery (SMA) angle. Nevertheless, the cut-off value of the SMA angle is controversial and variable. Therefore, the present study evaluated the optimal SMA angle to maximize diagnostic performance for NCS diagnosis by conducting a meta-analysis.
METHODS: We comprehensively searched the English literature related to the diagnosis of NCS from the perspective of SMA (from the date of database inception to June 2022). The accuracy of an SMA angle less than 41° in the diagnosis of NCS was evaluated by calculating the pooled sensitivity (SEN), pooled specificity (SPE), positive likelihood ratio (LR+), negative likelihood ratio (LR-), summary receiver operating characteristic (SROC) curve and area under the curve (AUC) value. The I2 test and meta-regression analysis were used to assess heterogeneity and sources of heterogeneity, respectively. Publication bias was assessed using Deeks\' funnel plot asymmetry test.
RESULTS: Six studies (526 patients) met the inclusion criteria. SEN and SPE were 0.94 (95% confidence interval (CI) 0.80-0.99) and 0.85 (95% CI 0.65-0.94), respectively. The LR + value was 6.0, and the LR- value was 0.07, revealing that SMA angles less than 41° exhibited an excellent ability to help confirm or exclude NCS. Additionally, SROC curves showed that the AUC of SMA angles less than 41° for the diagnosis of NCS was 0.96, indicating that SMA angles less than 41° have good efficacy for helping to diagnose NCS.
CONCLUSIONS: This study explored the diagnostic efficacy of the cut-off value of the SMA angle by meta-analysis. According to the high SPE and SEN results, SMA angles less than 41° have good efficacy in facilitating NCS diagnosis.

Superior mesenteric artery syndrome (SMAS) is a rare and unpredictable complication after correction spine surgery for adolescent idiopathic scoliosis (AIS). The management of this condition is poorly investigated, with controversial outcomes. This investigation systematically reviewed current evidence on pathogenesis, risk factors, management, and outcomes of SMAS following correction spine surgery for AIS. The present systematic review was conducted according to the 2020 PRISMA statement. All the included investigations reported SMAS presentation following scoliosis correction surgery in AIS. 29 articles with 61 eligible patients were included in this review. The mean age of the patients was 15.8 ± 7.2 years. The mean weight was 45.3 ± 8.0 kg, the mean height 159.6 ± 13.6 cm, and the mean BMI 16.5 ± 2.9 kg/m2. The mean duration of the treatment for SMAS was 21.6 ± 10.3 days. The mean interval between spine surgery and symptoms of SAMS was 69 days, with high between-studies variability (3 days to 4 years). Prompt identification of risk factors and an early diagnosis are necessary to manage SMAS and reduce the risk of complications. Additional investigations are required to establish risk factors and diagnostic criteria.Level of evidence Level IV, systematic review.

Superior mesenteric artery (SMA) syndrome is the compression of the third portion of the duodenum between the abdominal aorta and the superior mesenteric artery. Although multifactorial, the most frequent cause of SMA syndrome is significant weight loss and cachexia often induced by catabolic stress. SMA syndrome resulting from scoliosis surgery is caused by a reduction of the aortomesenteric angle and distance. Risk factors include rapid weight loss, malnutrition, and a rapid reduction in the mesenteric fat pad and are the most common causes of a decrease in the aortomesenteric angle and distance. Surgically lengthening the vertebral column can also lead to a reduction of the aortomesenteric distance, therefore, has been identified as a risk factor unique to spinal surgery. Despite a reported decline in SMA syndrome cases due to improved surgical techniques, duodenal compression is still a risk and remains a life-threatening complication of scoliosis surgery. This article is a cumulative review of the evidence of being underweight or having a low body mass index as risk factors for developing SMA syndrome following surgical scoliosis instrumentation and correction.

Intestinal obstruction is a common surgical emergency with high morbidity and mortality. Patients presenting with features of small bowel obstruction need urgent evaluation to avoid complications such as bowel gangrene, perforation, or peritonitis. Imaging is necessary in most cases of suspected bowel obstruction, to take an appropriate decision, for apt patient management. Among the common causes of small bowel obstruction, adhesions, external herniae, malignancies, and Crohn\'s disease top the chart. Imaging helps in determining the presence of obstruction, the severity of obstruction, transition point, cause of obstruction, and associated complications such as strangulation, bowel gangrene, and peritonitis. This review is based on the cases with unusual causes of bowel obstruction encountered during our routine practice and also on the extensive literature search through the standard textbooks and electronic databases. Through this review we want our readers to have sound knowledge of the imaging characteristics of the uncommon yet important causes of bowel obstruction. We have also revisited and structured a checklist to simplify the approach while reporting a suspected case of small bowel obstruction. Imaging plays a key role in the diagnosis of small bowel obstruction and in determining the cause and associated complications. Apart from the common causes of small bowel obstruction, we should also be aware of the uncommon causes of small bowel obstruction and their imaging characteristics to make an accurate diagnosis and for apt patient management.

Superior mesenteric artery syndrome (SMAS) is a rare cause of duodenal obstruction which is characterized by compression of the duodenum due to narrowing of the space between the superior mesenteric artery and aorta. Incomplete duodenal obstruction due to SMAS in neonates is rarely reported in the literature. In this case, it is a full-term 2-day-old male with the complaint of recurrent vomiting starting soon after birth. The patient was diagnosed with SMAS and duodenoduodenostomy was performed. Accompanying Meckel\'s diverticulum was excised.
El síndrome de la arteria mesentérica superior (SMAS) es una causa rara de obstrucción duodenal que se caracteriza por la compresión del duodeno debido al estrechamiento del espacio entre la arteria mesentérica superior y la aorta. La obstrucción duodenal incompleta por SMAS en recién nacidos rara vez se informa en la literatura. En este caso se trata de un varón de 2 días nacido a término que presenta vómitos recurrentes desde poco después del nacimiento. El paciente fue diagnosticado de SMAS y se le realizó duodenoduodenostomía. Se extirpó el divertículo de Meckel que lo acompañaba.

Vascular compression syndromes are a diverse group of pathologies that can manifest asymptomatically and incidentally in otherwise healthy individuals or symptomatically with a spectrum of presentations. Due to their relative rarity, these syndromes are often poorly understood and overlooked. Early identification of these syndromes can have a significant impact on subsequent clinical management. This pictorial review provides a concise summary of seven vascular compression syndromes within the abdomen and pelvis including median arcuate ligament (MAL) syndrome, superior mesenteric artery (SMA) syndrome, nutcracker syndrome (NCS), May-Thurner syndrome (MTS), ureteropelvic junction obstruction (UPJO), vascular compression of the ureter, and portal biliopathy. The demographics, pathophysiology, predisposing factors, and expected treatment for each compression syndrome are reviewed. Salient imaging features of each entity are illustrated through imaging examples using multiple modalities including ultrasound, fluoroscopy, CT, and MRI.

BACKGROUND: Superior mesenteric artery syndrome (SMAS) is a rare cause of upper intestinal obstruction. This occurs due to duodenal compression between the superior mesenteric artery and the aorta. Anatomical alterations, eating disorders, after some surgical procedures, and trauma are frequent causes of this rare syndrome. Diabetes is a highly prevalent disease that can cause gastroparesis in up to 12 %. Its association with SMAS is extremely rare and challenging to identify.
METHODS: A 32-year-old man experienced nausea and vomiting after diagnosis and treatment for type II diabetes. He was treated for diabetic gastroparesis for 2 years without improvement until he lost 40 kg of weight. After imaging studies, a distance between the superior mesenteric artery and the aorta of 5.3 mm and an angle of 17 degrees were detected, corroborating the diagnosis of SMAS syndrome. Due to medical failure, surgical treatment via duodenojejunostomy was performed.
CONCLUSIONS: Diabetes is a very prevalent disease in the world population that can cause gastrointestinal symptoms. In our patient, diabetic gastroparesis delayed the diagnosis of SMAS until severe symptoms of upper intestinal obstruction and significant weight loss occurred. In our patient, due to medical failure, surgical treatment significantly improved his symptoms and stopped his weight loss.
CONCLUSIONS: Superior mesenteric artery syndrome is a rare syndrome, and challenging to differentiate from diabetic gastroparesis. Delays in management may result in excessive weight loss. Surgical treatment can improve symptoms and weight loss.

BACKGROUND: Superior mesenteric artery (SMA) syndrome is a rare cause of duodenal obstruction by extrinsic compression between the SMA and the aorta (SMA-Ao). Although the left lateral recumbent position is considered effective in the treatment of SMA syndrome, individual variations in the optimal patient position have been noted. In this report, we present two elderly cases of SMA syndrome that exhibited rapid recovery due to ultrasonographic dynamic evaluation of the optimal position for each patient.
METHODS: Case 1: A 90-year-old man with nausea and vomiting. Following diagnosis of SMA syndrome by computed tomography (CT), ultrasonography (US) revealed the SMA-Ao distance in the supine position (4 mm), which slightly improved in the lateral position (5.7-7.0 mm) without the passage of duodenal contents. However, in the sitting position, the SMA-Ao distance was increased to 15 mm accompanied by improved content passage. Additionally, US indicated enhanced passage upon abdominal massage on the right side. By day 2, the patient could eat comfortably with the optimal position and massage. Case 2: An 87-year-old woman with vomiting. After the diagnosis of SMA syndrome and aspiration pneumonia by CT, dynamic US confirmed the optimal position (SMA-Ao distance was improved to 7 mm in forward-bent position, whereas it remained at 5 mm in the supine position). By day 7 when her pneumonia recovered, she could eat with the optimal position.
CONCLUSIONS: The optimal position for SMA syndrome varies among individuals. Dynamic US appears to be a valuable tool in improving patient outcomes.

Ectopic pancreas refers to pancreatic tissue that lacks vascular or anatomical connection with the main body of the pancreas. Superior mesenteric artery syndrome involves the compression of the third part of the duodenum between the aorta and the superior mesenteric artery. We present a case of a 12-year-old female with a 4-year history of recurrent episodes of severe epigastric pain, improved by sitting and leaning forward, and occurred monthly for nearly 48 h. Radiological findings confirmed the diagnosis of superior mesenteric artery syndrome. However, further investigation revealed the presence of ectopic pancreas. Surgical intervention successfully treated both conditions. The patient presented with severe abdominal pain, and although there was a diagnosis of superior mesenteric artery syndrome, the pain was not entirely attributable to this condition, as there was no correlation with food intake, and the degree of obstruction was mild. Further investigations revealed the presence of ectopic pancreas, which provided an explanation for the severity of the pain. This case highlights the need for further research on the potential association between superior mesenteric artery syndrome and ectopic pancreas.