SS18 - Outcomes of Median Arcuate Ligament Release in an International, Multi-Institutional Cohort

Objectives: Median arcuate ligament syndrome (MALS) is an uncommon disease diagnosed and treated by several surgical specialties. Prior research is limited to institutional case series, making the optimal approach to median arcuate ligament release (MALR) unclear. The objective of this study is to compare the outcomes of approaches to MALR.

Methods: Vascular Low-Frequency Disease Consortium is an international multi-institutional research consortium. Participants contributed standardized data on outcomes of open, laparoscopic (trans- or retroperitoneal), and robotic-assisted laparoscopic MALR performed between 2000-2020. The primary outcome was treatment failure, defined as no improvement in MALS symptoms after MALR or recurrence of symptoms between MALR and last clinical follow-up. Factors associated with treatment failure were determined using multivariable Cox proportional hazards model.

Results: Twenty-three institutions contributed data on 484 patients. Mean age was 39.5±16.0 years and 78.5% were female. Median symptom duration was 18 months (IQR: 8-48). Pain was present in 97.5% of patients, most commonly epigastric (75.6%). Open surgical approach was used in 215 (44.4%), laparoscopic in 221 (45.7%), and robotic in 48 (9.9%). Perioperative complications occurred in 19.4% (open: 30.2% vs. laparoscopic: 9.1% vs. robotic 18.8%; p< 0.001). Median follow-up was 1.4 years (IQR: 0.3-4.0). In terms of the best symptom improvement within the first year after MALR, 262 (54.1%) had complete relief, 118 (24.4%) had partial relief, and 76 (15.7%) had no relief. Kaplan Meier estimation of 1- and 5-year freedom-from-treatment failure was 58.8% (95%CI: 53.5%-63.7%) and 26.7% (95%CI: 20.0%-33.8%), respectively. Open and laparoscopic release had similar long-term outcomes, but patients treated with robotic-assisted MALR had higher rates of treatment failures (Figure; 1-year freedom from failure: open: 62.7%; laparoscopic 61.8%; robotic: 20.3%;p < 0.001). Risk factors associated with treatment failure were robotic MALR (HR 2.6 [vs. open MALR];p < 0.001), history of abdominal cancer (HR 7.7;p=0.001), atypical pain location (back, lower abdominal, or inguinal; HR 1.3;p=0.048), no response to preoperative celiac plexus block (HR 2.2;p=0.046), and dysphagia (HR 1.9; p=0.047). Patients with none of these risk factors had a 67.1% 1-year freedom from failure compared to 55.1% in patients with ≥1 risk factors (p=0.001).

Conclusions: Patients without the above-identified risk factors were more likely to remain symptom-free after MALR; however, treatment failure after MALR was high. Long-term failure was similar after open and laparoscopic release, although open release was associated with higher perioperative morbidity. Operative candidates for MALR should be counseled accordingly on the transitory symptom relief that occurs in many patients who undergo MALR procedures.