LES Involvement Pattern in Achalasia Cardia
The lower esophageal sphincter (LES) in achalasia cardia is involved symmetrically, affecting the entire circumference of the sphincter uniformly.
Pathophysiologic Basis for Symmetric Involvement
The symmetric involvement of the LES in achalasia stems from the underlying disease mechanism—inflammation and destruction of the myenteric plexus ganglion cells throughout the distal esophagus and LES 1. This pathologic process affects the inhibitory innervation uniformly around the entire sphincter circumference, leading to:
- Circumferential loss of inhibitory neurons: The ganglion cell destruction occurs throughout the myenteric plexus without preferential involvement of any particular segment 1
- Uniform functional impairment: The LES demonstrates absent or incomplete relaxation in response to swallowing across its entire circumference 2
- Symmetric pressure elevation: Manometric studies show elevated resting LES pressure that is uniform rather than segmental 3, 4
Clinical and Therapeutic Implications
The symmetric nature of LES involvement has direct implications for treatment approaches:
- Circular muscle myotomy technique: During POEM procedures, a circular muscle myotomy is performed within the submucosal tunnel, targeting the uniformly affected circular muscle layer around the entire LES circumference 5
- 360-degree treatment requirement: Both laparoscopic Heller myotomy and POEM address the LES by creating a myotomy that disrupts the symmetrically elevated sphincter pressure 5
- Uniform pressure reduction: Successful treatment results in symmetric reduction of LES pressure across all measurement points 3, 4
Diagnostic Confirmation
High-resolution manometry demonstrates the symmetric involvement pattern:
- Integrated relaxation pressure (IRP): This measurement captures the adequacy of LES relaxation across multiple sensors positioned circumferentially around the sphincter, showing uniformly elevated values in achalasia 5
- Distention studies: Research using balloon distention shows markedly impaired LES relaxation response uniformly, regardless of whether patients have dilated or non-dilated esophagus 2
The symmetric involvement distinguishes achalasia from other conditions that may cause asymmetric or segmental sphincter dysfunction, such as mechanical obstruction from tumors or extrinsic compression 5.