AHALASIA oesophagus

Achalasia (a Greek term meaning “does not relax”) is a rare motility disorder characterized -by an absence of normal oesophageal peristalsis, -and an increased basal resting pressure and- failure of complete relaxation of the lower oesophageal sphincter (LOS). Less than 5% of all cases ,present before the age of 15 years, giving an estimated incidence of 0.1 per 100,000 children.Males and females are equally affected.The condition was first described in 1674 by Willis who successfully treated a patient by repeated oesophageal dilatation using a sponge-tipped whale bone rod.In the early 1900s,based on observations in 100 reported cases, von Mikulicz suggested cardiospasm as the aetiology. In 1914 Heller described cardiomyotomy, a procedure that carries his name and forms the basis of all surgical approaches to this problem up to this date. The original operation consisted of two myotomies anteriorly and posteriorly on the lower oesophagus performed through a laparotomy.A single anterior cardiomyotomy was subsequently found to be adequate for symptomatic relief.The operation has been performed through a thoracotomy, as well as thoracoscopically and laparoscopically with or without an additional antireflux procedure.The pathogenesis of primary achalasia is not well understood. The most consistent histologic finding is a decrease or loss of myenteric ganglion cells, and this is more pronounced in advanced cases. The degenerativeprocess especially involves neurones producing neuropeptides and nitric oxide, the latter being identified as inhibitory neurotransmitters. Loss of inhibitory innervation causes increased tonic contraction and interference with normal relaxation of LOS, as well as a peristalsis of oesophageal body.There are no specific histologic changes in the oesophageal muscles. The cause of the neuronal damage remains unknown.Various mechanisms, including autoimmune, infectious, genetic, toxic and primary, have been proposed. The finding of myenteric inflammation, which is predominantly lymphocytic, the presence of serum auto-antibodies to myenteric plexus, and the increased frequency of class II histocompatibility

antigens in patients with achalasia supports an autoimmune aetiology. Similarity between achalasia and Chagas’ disease caused byTrypanosoma cruzi suggests that a neurotropic infectious agent may be responsible. Rarely, familial cases and association with microcephaly and the congenital anomalies have been observed.Patients usually present one or more of the following symptoms: vomiting/regurgitation of undigested food, progressive dysphagia, weight loss/failure to thrive, choking, retrosternal discomfort, and pulmonary problems such as recurrent coughing or chest infections.Vomiting and dysphagia are the commonest initial symptoms. Vomiting occurs more frequently in infants and young children whereas dysphagia is commoner in older children.Chest X-ray may show an air-fluid level in the oesophagus; there may be a soft tissue shadow in the mediastinum on the left hemithorax corresponding to a dilated lower oesophagus, and sometimes pneumonic changes.The characteristic radiological features of achalasia in a contrast swallow; are a proximal dilated oesophagus with a smooth tapering of the gastro-oesophageal junction (bird’s-beak sign or rat-tail deformity). There is an absence of coordinated peristaltic waves in the proximal oesophagus and a persistent failure of relaxation of the LOS on swallowing.Endoscopy confirms a dilated oesophagus which funnels smoothly towards a narrowed LOS. Retained food or yeast oesophagitis may be noted in the oesophagus.Although the LOS is closed, it provides little resistance to the advancing endoscope.Oesophageal manometry is the “gold standard”for the diagnosis of achalasia. Diagnostic features include a failure of relaxation of LOS on swallowing and absence of peristalsis in the body of the oesophagus.Features that are characteristic but not required for the diagnosis include elevated resting LOS pressure (>45 mmHg), and resting pressure in the oesophageal body exceeding that in the stomach.Symptomatic relief can be achieved by lowering LOS pressure with nitrate or calcium channel blocker (nifedipine) medication or with intrasphincteric injection of botulinum toxin. The need for life-long medication (with its associated side-effects) or

repeated injections, respectively, limits the role of medical therapy to those children who are not suitable for treatment by dilatation or surgery.Definitive treatment of achalasia consists of dilatation or oesophago-cardiomyotomy. Dilatation should be guided by endoscopy/fluoroscopy and can be achieved using either rigid or balloon dilators, the latter being the preferred choice in children. Pneumatic dilatation can be used for primary treatment or as a secondary procedure when symptoms recur after surgery. Our experience suggests that dilatation is less effective than surgery for long-term symptomatic relief.Figure 7.1 Figure 7.2Fi

Cardidiomyotomi-- anntireflux procedure/funduplicationHeller’s oesophago-cardiomyotomy remains the mainstay of treatment for achalasia and can be performed via the abdomen or thorax, either as an open procedure or by the minimally invasive approach, and with or without a concomitant fundoplication.Preoperatively, any yeast oesophagitis should have been eradicated with antifungal medication. The patient is kept on clear fluids a day prior to surgery to minimize the risk of aspiration of retained food on anaesthesia induction. Preoperative endoscopy ensures complete emptying of dilated oesophagus. A large feeding tube or a balloon catheter is introduced

into the stomach.Depending on the surgeon’s preference, surgical access can be achieved via the abdomen or left thorax.The abdominal approach is more popular, and allows concomitant fundoplication to be performed more easily.With the patient supine, an upper midline is made for laparotomy. For laparoscopic access, the patient is placed in a lithotomy position with the surgeon at the end of the operating table; four to five ports are placed as shown. The telescope is placed in the supra-umbilical port To expose the oesophagus in the open procedure, the left lobe of the liver is retracted superiorly and medially; the left triangular ligament may be divided to enhance the exposure. For the laparoscopic approach,a cotton-tipped rod is inserted into the epigastric port to retract the caudate lobe of the liver cephalad. Instrumentation is carried out via the remainingports ).7The phreno-oesophageal ligament is incised. The anterior vagus is seen on the anterior wall of the oesophagus and should be preserved. The hiatal window is identified adjacent to the caudate lobe and thetissues between the oesophagus and the crura are divided.The abdominal oesophagus is further freed by blunt dissection into the posterior mediastinum, taking care not to penetrate the pleura proximally. The posterior vagus is preserved. A cotton tape encirclingthe cardio-oesophageal junction is used to retract the abdominal oesophagus caudally. The site of myotomy is marked by electrocautery to the left of the anterior vagus.Myotomy extends for 4–6 cm above, and 0.5–1 cm below the cardio-oesophgeal junction. A superficial incision is made with the diathermy tip. The thickened oesophageal muscle is then divided with scissors andseparated by blunt dissection with grasping/preparation forceps until the submucosal plane is reached.Great care is taken to avoid mucosal perforation.Myotomy is continued proximally and distally with diathermy hook and blunt dissection until all constricting muscles have been separated and the mucosa is seen bulging outwards; the muscular edges

should be undermined for 50% of the oesophageal circumference. The gastro-oesophageal junction is recognized by the “collar-like” configuration of the circular muscles. The gastric muscles are usuallymore adherent to the mucosa.Mucosal perforation is tested by insufflation of the oesophagus; if present, this should be repaired by fine suture.A widened hiatus should be narrowed by one or two non-absorbable deep sutures placed through the crura. The wound is closed in the usual manner.FiTo avoid the long-term complication of gastro-oesophageal reflux after myotomy, many surgeons recommend a concomitant fundoplication as an antireflux procedure. ThanksDetails of the procedure are separately described (.The fundoplication should be loose to avoid dysphagia. A posterior 180° (Toupet) fundoplication can be performed over the distal 1–1.5 cm of the oesophagus. The fundus is sutured separately to the cut edge of the oesophageal muscle on either side using three non-absorbable interrupted sutures. This procedure holds the myotomy edges apart in addition to providing an antireflux mechanism.7Alternatively, an anterior 180° (Dor or Thal) fundoplication is performed. The anterior fundus is draped” over the anterior oesophagus, covering the myotomy. This procedure may be more appropriate for patients with mega-oesophagus as the posterior fundoplication is more prone to result in outflow obstruction. It may also provide additional cover after repair of a mucosal perforation.A nasogastric tube is left overnight. Fluid diet is commenced after a contrast study confirms the absence of a leak and when gastric stasis has resolved. Return to normal feeds is usually faster for laparoscopicprocedures.Oral medication with nifedipine or nitrates can resultin a 50% decrease in LOS but is commonly associated with side-effects such as headache. Experience of intrasphincteric injection of botulinum toxin is limited in children. Recent studies suggest a mean duration of effect of 4 months; more than half of the patients are expected to require a repeat injection within 6 months.Pneumatic dilatation has been reported to be effective in 50–90% of cases in selected small series.

Most authors, including ourselves, have been unimpressed with its efficacy as primary treatment in children with achalasia.Multiple dilatations are often required. Complications include oesophageal perforation and symptomatic gastro-oeosophageal reflux.Heller’s oesophago-cardiomyotomy is the method of choice for the treatment of achalasia in children.Long-term symptomatic relief is obtained in 86% of children after surgery. Most series report zero mortality.Complications include oesophageal perforation (10%), atelectasis and post-operative fever(42%), dysphagia (14%) and gastro-oesophageal reflux (20%).A poor result following oesophago-cardiomyotomy can be due to mega-oesophagus, incomplete myotomy or gastro-oesophageal reflux. Incomplete myotomy usually responds to secondary pneumaticdilatation. Gastro-oesophageal reflux is preventable by a concomitant fundoplication during myotomy; attempts to perform a fundoplication as a second operation after an initial myotomy without fundoplication is technically more difficult. Laparoscopic myotomy is gaining popularity. Transthoracic video-assisted Heller’s myotomy has also been performedsuccessfully. An additional fundoplication is easier to perform laparoscopically than thoracoscopically.Compared to open procedures, the minimally invasive approach results in superior cosmesis, less post-operative pain, earlier return to resumption of feeding (means: 2.7 days for laparoscopic procedure,9.0 days for open) and shorter hospital stay. Conversion to open myotomy is necessitated in 10% of laparoscopic procedures, usually as a result of intraoperative oesophageal perforation. With increasing experience, even oesophageal perforations can be repaired laparoscopically.SELECT ED BIBLIOGRAPHY