Acute median arcuate ligament syndrome after pancreaticoduodenectomy

Discussion

The pancreaticoduodenal arcades make up the major collateral circle that allows retrograde flow through the GDA in case of CAS. They allow for blood to reach the hepatic, gastric, splenic, and pancreatic arteries when the celiac trunk is compromised [7].

The preoperative diagnosis of MALS is essential so that this arcade may be preserved [8, 9]. It is not always possible to diagnose MALS before proceeding with pancreatic resection during PD. Failure to demonsrate MALS before or during PD could potentially cause major morbidity, leading to ischemic and fatal complications [11, 17–19].

Three-dimensional CT angiography shows a characteristic hook pattern on the anterior proximal celiac axis when it is compressed by the median arcuate ligament [13, 14]. Gaujoux et al. [15] reported that multidetector CT, including lateral views, can detect significant arterial stenosis with 96 % sensitivity and determine the etiology of CA stenosis with 92 % accuracy.

If MALS is diagnosed before PD, various methods are available for revascularization before or during the procedure: these include open or laparoscopic median arcuate ligament division, a vascular bypass procedure, or endovascular stenting [16–18, 21–25].

Intraoperative trial clamping of the GDA should be performed before breakdown of the collateral circulation during PD, even if preoperative CT does not demonstrate MALS [2]. If MALS is present, this clamping will markedly decrease the hepatic artery pulsation as evaluated by digital palpation or intraoperative Doppler ultrasonography [3]. If MALS is diagnosed during PD, the median arcuate ligament must be divided at the beginning of the procedure, before GDA ligation or pancreatic division [15, 20]. This safe and fast procedure permits trunk decompression and resolution of ischemic disorders in up to 89 % of patients [15].

MALS can develop acutely after PD in patients with normal hepatic artery flow during GDA clamping. Sanchez et al. [7] reported the first patient with acute onset MALS after PD who did not demonstrate hepatic artery flow impairment during GDA clamping. They were able to treat their patient conservatively. We report herein a second such patient who had no evidence of hepatic artery flow impairment during GDA clamping and pancreatic transection.

Since the appearance of MALS after PD is very rare, the appropriate treatment has to be determined according to the patient’s general status. We decided on exploratory laparotomy since our patient had abundant hepatic cytolysis. Also influencing our decision, his liver enzymes, INR, and CRP worsened abruptly within 12 h of the original surgery and rapidly increased by 24 h after PD. Repeat CT also showed widespread liver ischemia. At re-exploration, we noted bile leakage from the suture points of the hepaticojejunostomy, probably due to the decreased blood flow from the common hepatic artery. Eventually, our patient developed a biliary fistula that required extended hospitalization.

There is no known explanation for this acute onset of MALS after PD in a patient with normal celiac anatomy. Sanchez et al. [7] tried to explain this phenomenon as occurring in patients with pre-existing nonsignificant CAS that is exacerbated by either extended lymphadenectomy of the celiac region or by the prolonged bent back position of the patient during surgery. However, our patient’s celiac lymphadenectomy and duration of the surgery were not different from our other patients who have not developed MALS. Although our patient underwent NACRT followed by PD, the field of radiation did not include the region of the celiac trunk. We hypothesize that a very tight median arcuate ligament presented in this young patient in addition to lymph-node clearance around the celiac trunk might induce the stenosis.