الفهرس 
Anatomy of the EsophagusOnly 14 pages are availabe for public view
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Abstract
The oesophagus is a hollow muscular tube guarded by upper and lower oesophageal sphincters and extends from the lower border of the cricoid cartilage (sixth cervical vertebra) to the stomach. The cardia denotes the junction between the oesophagus and the stomach. The only reliable and constant anatomical landmark of this is made by sling or oblique fibers of the stomach but these cannot be identified endoscopically. In the clinical context, therefore, the term cardia is used to describe the Junctional zone between the oesphagus and stomach.
Achalasia is a primary esophageal motility disorder characterized by the loss of peristalsis and an inability of the lower esophageal sphincter (LES) to relax resulting in dysphagia, regurgitation, chest pain, and weight loss the clinical hallmark.
Achalasia occurs at all ages; the mean occurrence is in middle age and affects both sexes and all races equally. It is not a common disease, an average incidence of approximately 0.4 to 1.1 cases per 100000 populations.
The etiology and pathogenesis of idiopathic achalasia are still unclear, although a viral cause, genetic influences (associations with HLA loci) and autoimmune processes have been postulated. Degeneration and significant loss of nerve fibers, associated with an inflammatory infiltration of the myenteric plexus in idiopathic achalasia, provide evidence of an immune-mediated destruction of the myenteric plexus, possibly through apoptotic process.
The most serious complication of the esophageal achalasia is the development of carcinoma of the esophagus. The frequency of midesophagus carcinoma in patients with achalasia varies from 2% to 7%. The occurrence is highest in patients who have received inadequate or no therapy for achalasia.
Crucial to the diagnosis of idiopathic achalasia is exclusion of secondary achalasia syndromes (pseudo-achalasia). Achalasia is best detected by functional studies, either fluoroscopy during a barium swallow or esophageal manometery. The radiographic features are aperistalsis, esophageal dilatation, and minimal LES opening with a bird-beak appearance; defining manometric features are aperistalsis and incomplete LES relaxation. The amplitude of pressure at the LES is found to be 2 or 3 times higher than normal in the body of the esophagus and resting pressures are higher than fundic pressures because of dilatation and retention, whereas pressure at the UES is within the normal range.
Effective peristalsis is rarely restored with successful treatment, but improvement in esophageal emptying and reduction in the esophageal diameter are generally expected. Nitrates and calcium channel blockers decrease LES pressure in a dose-dependent manner, with a maximum effect of approximately 50%, thereby temporarily relieving dysphagia.
There are currently three different treatment modalities available: botulinum toxin injection, pneumatic dilation, and Heller myotomy. All three are focused on decreasing the LES resting pressure there by allowing the distal esophagus to empty with the aid of gravity.
Laparoscopic management of achalasia has been proven as safe and effective as conventional myotomy, with little morbidity, shorter hospital stay, and quicker return to daily activities. The value of adding an antireflux procedure to the myotomy for preventing or reducing the incidence of reflux esophagitis is a matter of controversy.
Some authors believe that thoracoscopic short esophagomyotomy without an anti-reflux procedure is the primary treatment of choice for all symptomatic patients with esophageal achalasia.
The concept of natural orifice transluminal endoscopic surgery (NOTES) has inspired endoscopists and endoscopic surgeons to create less invasive treatment even for esophageal achalasia.
So far, treatments including Botox injection and balloon dilation have been commonly performed as firstline endoscopic treatments for achalasia, if those are ineffective, laparoscopic procedures are generally selected as the next step.
Esophagectomy may be needed in those with dilated esophagus (> 8 cm) with poor response to an initial myotomy.