Because median arcuate compression can be found in both symptomatic and asymptomatic patients, imaging alone may not identify patients who will improve after MAL surgical release. The percutaneous celiac ganglion block has been used for many years to control intractable pain for patients with chronic pancreatitis or intra-abdominal cancers. Although permanent block can be obtained by injecting alcohol, a temporary celiac ganglion injection with local anesthetic performed under CT or fluoroscopic guidance (Fig. 27.4) may help to identify patients who would improve from surgical treatment [21]. Although promising, improvement from ganglion block does not absolutely predict future success from MAL surgical release, and further studies are still necessary.

Gastric tonometry (See Chap. 6) has also been proposed as a preoperative predictor of success from MAL release. Mensink et al. reported on 43 patients with significant celiac compression of which 30 had ischemia based on gastric exercise tonometry [22]. Of those 30 patients, 29 underwent MAL release and/or revascularization, and 83 % were asymptomatic at 39 months of follow-up. Repeat tonometry in the patients who were asymptomatic was improved in 100 % but only improved in 25 % of patients with persistent symptoms, implicating gastric ischemia an etiology.

Despite an overlap in symptoms, MALS is distinct from chronic mesenteric ischemia. As opposed to chronic mesenteric ischemia, MALS will not progress to cachexia, bowel gangrene, or death. In addition, MALS typically involves only the celiac artery, although occasionally the ligament can compress the SMA as well. Although initial general symptoms of abdominal pain, postprandial pain, and food fear may lead to the differential diagnosis of both MALS and chronic mesenteric ischemia, careful history and excellent imaging can often easily differentiate between the two diseases.