Efficacy of Endoscopic Intrapyloric Injection of Botulinum Toxin in the Treatment of Gastroparesis: A Systematic Review and Meta-Analysis

Introduction: Observational studies suggest symptomatic improvement after intrapyloric injection of Botulinum toxin in treating gastroparesis in an attempt to paralyze the pyloric sphincter complex. However, a limited number of clinical trials failed to demonstrate any benefit to this therapy. We conducted a systematic review and meta-analysis to ascertain the outcomes of intrapyloric injection of Botulinum toxin in the treatment of gastroparesis. Methods: We conducted a comprehensive search of Ovid Cochrane, Ovid Embase, Ovid Medline, Scopus, and Web of Science (inception to September 2022) to identify studies reporting on the use of intrapyloric injection of Botulinum toxin in gastroparesis. The primary outcome was overall clinical success while secondary outcomes were improvement in Gastroparesis Cardinal Symptom Index (GCSI), Gastric Emptying Study (GES); improvement in nausea/vomiting, fullness/distension, and bloating/belching. Clinical success was measured as improvement in either GES or GCSI. A meta-analysis of proportions was done for all primary and secondary outcomes. Results: A total of 8 studies were included. The study consisted of 156 patients including 29 males and 104 females; mean age of 43.6+/-7.4 years. Etiology was diabetes in 35.2% (55/156), idiopathic in 55.2% (86/156) and others in 9.6% (15/156). Overall clinical success was seen in 64.3% of patients (95% CI: 45.7-79.4%; I2 68%). Improvement in GCSI was seen in 60.4% of patients (95% CI: 39.3-78.3%; I2 72%) while improvement in GES was seen in 70.2% (95% CI: 55.0-81.9%; I2 0%). Symptomatic improvement in nausea/vomiting occurred in 25.6% (95% CI: 15.5-39.3%; I2 3%), fullness/distension occurred in 26.9% (95% CI: 2.0-86.7%; I2 85%) and bloating/belching occurred in 31.4% (95% CI: 5.4-78.5 %; I2 83%). Conclusion: Our meta-analysis demonstrates improvement in objective criteria for gastroparesis like GCSI and GES. However, improvement in objective scores did not translate into improvement in subjective symptoms for the patients. The study demonstrates a limited benefit of intrapyloric injection of Botulinum toxin in gastroparesis.