1. 2020;23;E441-E450Opioid Reduction and Long-Term Outcomes in Abdominal Myofascial Pain Syndrome (AMPS): A 6-Year Longitudinal Prospective Audit of 207 Patients
   Prospective Review
   G Niraj, MD, and Sachin Alva, FRCA.

BACKGROUND: Abdominal myofascial pain syndrome is an important cause of refractory chronic abdominal pain. It causes severe functional impairment resulting in significant patient distress and substantial health care costs, and it can be a challenge to treat. Opioid consumption is a recognized challenge in this cohort.

STUDY DESIGN: We conducted a prospective longitudinal audit over a 6-year period.

SETTING: The study was conducted at a tertiary pain medicine clinic in a university teaching hospital.

METHODS: Over a 6-year period, 234 patients diagnosed with chronic abdominal pain secondary to abdominal myofascial pain syndrome were included in a structured management pathway. Long-term outcomes were prospectively audited at a tertiary-care university hospital. Patients who completed a minimum of 12 months in the pathway were included. The main outcome was reduction in opioid consumption. Treatment outcomes included treatment failure, number of patients with clinically significant pain relief, durable pain relief, and long-term pain relief. Other outcomes included patient satisfaction and success in maintaining gainful employment.

RESULTS: Two hundred seven patients completed a minimum of 12 months of follow-up. Seventy-eight percent (162 of 207) were on opioids at presentation. There was significant reduction in opioid consumption at >= 12 months’ follow-up. Among patients who underwent interventional management, clinically significant relief was reported in 31 patients (31 of 180, 17%), durable relief in 71 patients (71 of 180, 40%) and long-term relief lasting 12 months in 23 patients (23 of 180, 13%). Twenty-six patients (26 of 180, 15%) reported cure from symptoms. The treatment failure rate was 15%.

LIMITATIONS: This was an open-label study that took place at a single center.

CONCLUSION: The authors present the first prospective practice-based evidence report on the long-term outcomes in patients diagnosed with abdominal myofascial pain syndrome. There was significant reduction in opioid consumption at 12 months and over two-thirds of patients reported significant durable relief on long-term follow-up. The authors present their recommendation for managing this complex group of patients.

KEY WORDS: Abdominal myofascial pain syndrome, abdominal plane blocks, chronic abdominal wall pain, opioid reduction, quadratus lumborum block, TAP block, viscerosomatic convergence