Optimal management of functional anorectal pain: a systematic review and network meta-analysis

Functional anorectal is idiopathic and characterised by severe and potentially intractable anorectal pain. The current review aims to appraise available evidence for the management of functional anorectal pain and synthesise reported outcomes using network meta-analysis. PubMed, CENTRAL and Web of Science databases were searched for studies investigating treatments for functional anorectal pain. The primary outcome was clinical improvement of symptoms and the secondary outcome was pain scores reported during follow-up. A Bayesian network meta-analysis of interventions was performed. A total of 1538 patients were included from 27 studies. Intramuscular injection of triamcinolone, sacral neuromodulation (SNM) and biofeedback were most likely to be associated with improvement in symptoms [SUCRA (triamcinolone) = 0.79; SUCRA (SNM) = 0.74; SUCRA (Biofeedback) = 0.61]. Electrogalvanic stimulation (EGS), injection of botulinum toxin A and topical glyceryl trinitrate (GTN) were less likely to produce clinical improvement [SUCRA (EGS) = 0.53; SUCRA (Botox) = 0.30; SUCRA (GTN) = 0.27]. SNM and biofeedback were associated with the largest reductions in pain scores [mean difference, range (SNM) = 4.6-8.2; (Biofeedback) = 4.6-6]. As biofeedback is noninvasive and may address underlying pathophysiology, it is a reasonable first-line choice in patients with high resting pressures or defecation symptoms. In patients with normal resting pressures, SNM or EGS are additional options. Although SNM is more likely to produce a meaningful response compared to EGS, EGS is noninvasive and has less morbidity. Whilst triamcinolone injection is associated with symptomatic clinical improvement, the magnitude of pain reduction is less.