To compare anterior versus posterior myotomy during POEM across all major clinical, safety, physiologic, and procedural outcomes using the latest available time points from randomized trials and high-quality comparative studies.

A systematic review and meta-analysis of RCTs and cohort studies was performed. Outcomes included clinical success (Eckardt score ≤3), adverse events (overall and mucosotomy-specific), GERD (pH, endoscopy, symptoms), manometric response, and procedural metrics (total procedure time, closure time, hospital stay). For binary outcomes, pooled odds ratios (OR) were calculated; for continuous outcomes, mean differences (MD) were synthesized using random-effects models. Long-term data from RCT extensions were incorporated when available.

A total of four RCTs and multiple cohort studies (≈1,200 patients) were included.

Clinical success: No significant difference between anterior and posterior POEM at 12 months (OR ≈ 1.02; RR ≈ 0.98). Long-term RCT follow-up (≥2 years) also showed similar results (85% vs 79%, p > 0.40).

GERD: Incidence of GERD by pH, endoscopy, and symptom scores was similar across orientations (pooled OR ~1.0 across modalities).

Adverse events: Posterior POEM demonstrated significantly fewer overall adverse events (RR ≈ 0.63) and markedly reduced mucosotomy risk (RR ≈ 0.42).

Procedural outcomes: Posterior POEM was associated with shorter incision-closure time (MD −2.28 minutes) and, in observational datasets, shorter overall procedure duration. Anterior POEM demonstrated a statistically shorter but clinically negligible hospital stay (MD +0.31 days).

Manometry: LES pressure and IRP reduction were equivalent between approaches (MD ≈ 0), with similar normalization rates.

Anterior and posterior POEM achieve equivalent clinical success, similar GERD rates, and comparable physiologic improvement. Posterior myotomy offers procedural advantages: reduced adverse events and faster closure time without compromising clinical efficacy. These findings support the routine use of posterior orientation, particularly in centers prioritizing efficiency and mucosal safety, while affirming that either approach yields excellent therapeutic results.