Post-Heller Myotomy Manometry Findings
After successful Heller myotomy, esophageal manometry typically demonstrates a significant reduction in lower esophageal sphincter (LES) resting pressure to approximately 10-14 mmHg (from pre-operative values of 30-45 mmHg), with improved but incomplete LES relaxation, while the esophageal body remains aperistaltic.
Key Manometric Changes
Lower Esophageal Sphincter Pressure
- Resting LES pressure decreases dramatically from pre-operative values of 32-44 mmHg to post-operative values of 7-14 mmHg 1, 2, 3, 4
- Optimal outcomes occur when post-operative LES pressure is ≤18 mmHg, with patients achieving this threshold reporting the fewest dysphagia symptoms 2
- LES residual pressure similarly decreases from approximately 16 mmHg to 5 mmHg 4
LES Relaxation
- LES relaxation rate improves from approximately 49% pre-operatively to 84% post-operatively 1
- However, complete LES relaxation during swallowing remains absent in most patients, particularly along the posterior esophageal wall 1
- Patients with persistent dysphagia often demonstrate incomplete LES relaxation in 2-3 directions 1
Esophageal Body Motility
- Aperistalsis persists after myotomy - this is the expected finding and does not change with surgery 1, 2
- Some studies report surprising findings of residual peristaltic activity (approximately 31% of sequences) after myotomy, though this remains controversial 5
- Food transit occurs primarily by gravity rather than coordinated peristalsis 1
- Esophageal body tone decreases from approximately 4.8 mmHg to -3.5 mmHg 4
Clinical Correlation with Outcomes
Predictors of Successful Relief
- Decrease in LES pressure >18 mmHg from baseline correlates with better dysphagia relief 2
- Absolute post-operative LES pressure ≤18 mmHg is associated with optimal symptom resolution 2
- Patients free of dysphagia typically have lower LES basal pressures (approximately 6 mmHg) compared to those with residual symptoms (approximately 15 mmHg) 4
Important Caveats
- Intraoperative manometry can confirm adequate myotomy when LES pressure drops below 5 mmHg, though this is not routinely performed 4
- The presence of preserved abdominal LES length (>1.5 cm) may help prevent post-operative reflux without compromising dysphagia relief 4
- Approximately 7-12% of patients experience residual or recurrent dysphagia despite manometric improvement 2, 4
Reflux Assessment
- Post-operative 24-hour pH monitoring typically shows normal or near-normal esophageal acid exposure (mean 3% time pH <4, normal <4.2%) 2
- Median DeMeester scores remain within normal limits (approximately 10, normal <22) 2
- Reflux symptoms do not reliably correlate with objective acid exposure on pH monitoring 2, 3
Common Pitfall
Do not expect restoration of normal peristalsis after myotomy - aperistalsis is the expected post-operative finding. The goal is adequate LES pressure reduction while maintaining enough residual tone to prevent severe reflux, not restoration of coordinated esophageal contractions.