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9.1 Etiology and Pathogenesis

Esophageal achalasia (EA) is a rare functional motility disorder of the esophagus of unknown origin, characterized by abnormal motility of the body of the esophagus associated with delayed or absent relaxation of the lower esophageal sphincter (LES), inducing stasis in the esophagus with subsequent dilatation.

Sir Thomas Willis described the disease in 1674 [1]. He did the first mechanical dilatation for achalasia, using an orally inserted cork-tipped whalebone. In 1881, Mikulicz described the disease as a cardiospasm, i.e., the symptoms were due to a functional problem rather than a mechanical one. Ernst Heller realized the first myotomy to release the symptoms in 1914 [2]. The procedure done by Heller was an anterior and a posterior myotomy. However it is still named after him, even if the procedure today differs. In 1929, Hurt and Rake realized that the disease was caused by a failure of LES to relax and coined the term achalasia (i.e., failure to relax).

The highest incidence in adults is between the fourth and seventh decades. Children count for 5 % of all cases of achalasia; thus it is an uncommon condition in pediatric population, appearing in 0.1–1/100,000 annually between 7 and 13 years of age. However today, progresses make diagnosis earlier than before. Our youngest patient was 1.1 year old [3–9].

The etiology is unknown. Achalasia is believed to be an acquired functional esophageal motility disorder. However its physiopathology remains unclear, and possibly there are several forms of the disease with different etiologies including primary disorder of the esophagus and “partial” achalasia. This could explain that the results of treatments are not as good as expected. Several studies have suggested that the genetic background may have a role in the pathogenesis [10]. It could be an autoimmune disease, genetically determined, then triggered by viral (Herpes), bacterial, or parasitic (Chagas’ disease caused by Trypanosoma cruzi) infections resulting in a loss in inhibitory neurons of myenteric plexus [11, 12]. In some patients it could be malformative very similar to Hirschsprung’s disease. The genetic theory is supported by the high frequency of congenital anomalies or associated syndromes such as the Down syndrome, the Allgrove syndrome (AAA syndrome, addisonianism-alacrima-achalasia), the congenital central hypoventilation syndrome, the Rozycki syndrome (deafness, vitiligo, esophageal achalasia), and the Hirschsprung disease [10, 13–16]. Achalasia is frequent in siblings or can be familial with an autosomal recessive mode [10, 17, 18]. It is frequently associated with an eosinophilic esophagitis.

However, this explains only partially the pathogenesis. Histology, electron microscopy, and immunohistochemistry provide answers. The Italian Camillo Golgi (1843–1926) invented the fixation and tissue stainings with methylene blue and silver impregnation. Thanks to this, the Spanish Santiago Ramon y Cajal (1852–1934) described the neuron and the organization of the central nervous system. They got together the Nobel Prize of Medicine for that in 1906. In 1911, Cajal, searching for a neural network to study, simpler than the brain, used the rabbit small intestine to find interstitial cells he believed to be the end cells of the sympathetic nervous system. His drawings of what we call after him the Interstitial Cells of Cajal (ICC) are still accurate. ICC can be studied due to electron microscopy and immunohistochemical staining for c-Kit [19].

The ICC are related to intestinal pacemaker activity [20]. However the esophagus has very few ICC associated with the myenteric plexus but has abundant intramuscular ICC (ICC-IM) dispersed throughout the circular and longitudinal muscle layers. ICC-IM are thought to be involved in pacemaking and slow-wave propagation in the stomach [20]. Three types of ICC have been described: the ICC-MY, ICC-IM, and ICC-SEP [20–23]. They are located, respectively, in the myenteric plexus between the circular and longitudinal muscle layers, within the muscle layers and within the septa between the circular muscle bundles. ICC are most frequent in the esophageal part of the LES but rare in the gastric part. The absence or reduction in the number of ICC causes abnormal electrical slow waves with a decreased contractility of smooth muscle cells, resulting in a diminished intestinal transit. Impaired production of nitric oxide (NO) and vasoactive intestinal peptide (VIP) affects both ICC and muscles thus inhibiting relaxation of the LES as it has already been suggested in intestinal pseudo-obstruction and Hirschsprung’s disease [19, 24]. Anomalies of the ICC have been evocated in diseases such as idiopathic gastric perforation, hypertrophic pyloric stenosis, intestinal pseudo-obstruction, meconium ileus, and Hirschsprung’s disease [21, 25]. Thus debated, ICC involvement in achalasia is highly probable [19, 21]. What is known today is that patients with achalasia have a loss of myenteric plexus and enteric neurons; a loss in number and modifications of the ultrastructure of the ICC, being replaced by fibrosis or inflammation (“plexitis”); and no immunoreactivity for VIP [19, 26, 27].

Because of the relatively low incidence of the disease in children, our knowledge is based on small series or extrapolated from adult studies. We ignore if achalasia in children differs from that in adults. For instance, esophageal manometry has allowed better description of esophageal primary disorders in children such as partial achalasia with various clinical conditions [28]. Unfortunately, no clinical or manometric features can differentiate the patients who present a favorable outcome under medication from those requiring surgery.

In addition, the environment could play a role that is not known yet. So achalasia appears to be a multifactorial and multimodal disease that remains partially understood.

9.2 Diagnosis and Pretreatment Work-Up

9.2.1 Symptoms

Achalasia can be difficult to recognize because there may be nonspecific symptoms that may include feeding aversion, failure to thrive, nonspecific regurgitation suggestive of gastroesophageal reflux (GER), and respiratory symptoms. The diagnosis is often delayed.

The most common complain is dysphagia. Children progressively refuse food intake, and then have special vomitings whose content is related to undigested previous meals. Dysphagia begins with solids but can reach the point where liquids cannot be absorbed (paroxysmal dysphagia). They complain retrosternal pains and pyrosis. Their relatives notice fetor. Secondary signs are dehydration, failure to thrive, and weight loss. Due to aspirations, respiratory symptoms (cough and repeated pneumonia) are often present [5, 7–9, 29].

9.2.2 Upper Gastrointestinal Contrast Study

The most common investigations performed in children are upper gastrointestinal contrast study (UGI) and manometry. The use of barium should be avoided in case of aspiration, and hydrosoluble contrasts should be preferred for the UGI. X-ray studies classically demonstrate a dilated esophagus that ends with “bird’s beak” like tapering of the distal esophagus. The presence or the absence of esophageal contractions on serial views should be mentioned (Fig. 9.1).

Fig. 9.1
figure 1

Upper gastrointestinal contrast study showing a dilated esophagus that ends with “bird’s beak” and the absence of esophageal contractions on serial views

Full size image

Even if the esophagogram study alone with all the classical signs can be pathognomonic, as the disease is not clearly understood and as many variations may occur, it is wise to confirm the achalasia with an esophageal manometry [30].

9.2.3 Esophageal Manometry

Esophageal manometry should be performed following the recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) [31], the American Gastroenterological Association [32], and other experts [29, 33, 34]. However, the adult recommendation to use a continuously perfused low-compliance system should not be followed in infants as it may provide an unacceptable amount of water in the esophagus. Thus miniature strain-gauge pressure transducers mounted within thin pediatric catheters should be preferred. Manometries should not be done under sedation, but we place the catheter using inhaled equimolecular mixture of oxygen and nitrous oxide (EMONO, equivalent of MEOPA) [35, 36].

Elevated resting LES pressure (>22 ± 10 mmHg), absent or low-amplitude peristalsis, or non-relaxing LES upon swallowing (relaxation rate <90 %) are diagnostic findings on esophageal manometry in children [4, 6, 17, 37]. However, the absence of some of these findings does not rule out the diagnosis of achalasia as LES function in children is heterogeneous. Partial relaxations are common, and normal LES relaxations after wet swallows may also be present on manometries [29]. Only 4.2 % patients had all four common manometric features (elevated LES pressure, abnormal LES relaxation, aperistalsis, increased intraesophageal pressure) for achalasia in Agrawal’s study (children and adults). Most of the 72 patients of his series had elevated increased intraesophageal pressure, elevated LES relaxation pressure, normal LES pressure, and low baseline impedance. The resting LES pressure can be normal in up to 40–70 % of achalasia patients [30].

9.2.4 Intraluminal Impedancemetry

Intraluminal impedancemetry (IIM) allows intraluminal measurements of electric impedance between several closely arranged electrodes during bolus passage. Impedance is inversely proportional to conductivity. When a highly conductive material is present inside the esophagus, the impedance decreases, i.e., with reflux, and increases with air. Combined multichannel IIM and esophageal manometry offers the ability to evaluate the relationship between esophageal contraction and bolus transit during the same swallow [30, 38]. Impaired bolus flow for liquid and viscous is found in most patients with achalasia as a translation of the aperistalsis of the esophagus. Thus, those combined investigations are useful to ensure achalasia and to understand the behavior of the esophagus.

9.2.5 High-Resolution Manometry (HRM)

The recently introduced high-resolution manometry (HRM) enlarges diagnostic investigations in esophageal dysmotility and may replace conventional manometry. However, the experience with using HRM in children is limited [39, 40]. HRM combines improvements in pressure-sensing technology with a greatly increased number of pressure sensors. In conventional manometry, the pressure sensors are spaced at 3–5 cm intervals. In HRM, 36 sensors are spaced at 1 cm and distributed longitudinally and radially along the probe. This allows simultaneous pressure recording in the esophagus. During swallow, the movements and pressure are recorded giving a topographic and cinematic view of the pressures in the esophagus from UES to LES. Pressure magnitude is encoded in color, conventionally in red for high pressures and blue for low [41].

This technique discriminates between different types of achalasia according to the LES but also to the intraesophageal pressure and movements. Thereby, achalasia has been classified into three types based on esophageal motility but helps to describe many other esophageal motility disorders as well (The Chicago Classification [42]). It provides an algorithmic scheme for diagnosis of esophageal motility disorders. Type I is characterized by the failed relaxation of the LES and 100 % failed peristalsis; Type II involves failed relaxation of the LES with no normal peristalsis and panesophageal pressurization with ≥20 % of swallows; Type III, or spastic achalasia, associates failed relaxation of the LES, with preserved fragments of distal peristalsis or premature (spastic) contractions with ≥20 % of swallows. Many other esophageal motility disorders are described such as distal esophageal spasm, hypercontractile esophagus, and absent peristalsis and statistically defined peristaltic abnormalities (weak peristalsis, frequent failed peristalsis, rapid contractions with normal latency, and hypertensive peristalsis). This Chicago classification has occasionally been used in children [39].

This technique contributes to better understand the variations of the outcomes after different treatments, as it appears that achalasia is not a unique pathology but that this term covers different diseases.

9.2.6 Endoscopy

Some authors use endoscopy only in case of unclear diagnosis. However, as others, we believe performing systematically an upper endoscopy is reasonable to rule out esophagitis, Trypanosoma cruzi, and other secondary causes of achalasia, eventually with biopsies [43]. In some cases we found food impactions filling the esophagus (like a fecaloma in the esophagus) that was not easy to empty. Once done, there was such an important underlying esophagitis that we postponed the surgery to give time to the inflammation to decrease and avoid perforation when doing the myotomy.

The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) provides guidelines on esophageal achalasia. The recommendations are that patients with suspected achalasia should undergo an UGI, an upper endoscopy, and an esophageal manometry to confirm the diagnosis, with strong evidences (level 3+) according to the GRADE system [44].

9.3 Treatments of Achalasia

As the pathogenesis of the disease remains unknown, no etiological therapy is available. Treatments focus on relief of symptoms by reducing the functional obstruction caused by a non-relaxing LES, in the hope that can restore esophageal emptying and peristalsis. They include medications, chemical paralysis of the LES, mechanical or pneumatic dilatations, and endoscopic or surgical esophagomyotomies with or without fundoplications. Because of the low incidence of the disease in children, treatments are based on small case series or extrapolated from adult studies. To date, there is no prospective randomized trial in the pediatric literature on achalasia, and a meta-analysis on seven retrospective reports is not conclusive due to the heterogeneity of the study designs and the various methods of treatment used both within and between studies [45]. Unfortunately adequate comparative data are lacking to determine the ideal treatment of pediatric achalasia.

9.3.1 Medications

Medications should be used sublingually because of the unpredictability of absorption if orally given. Nifedipine, a calcium channel blocker, inhibits the transmembrane calcium influx in cardiac and smooth muscle and has been primarily used to release the LES in adults, with efficiency between 13 and 19 % [46, 47]. It should be given 10–30 mg sublingually 30–45 min before meals in adults [44].

Other substances have been used in adults: long-acting nitrates (isosorbide dinitrate) and phosphodiesterase-5 inhibitors (sildenafil). There are few reports of short series on the use of nifedipine in children but with good results [48]. However the benefits are temporary, and the treatment cannot be used for long-lasting therapy due to secondary effects (orthostatic hypotension, headaches) occurring in 30 % of patients. However, it can be used as a bridge to relieve symptoms until another treatment is undertaken.

The SAGES recommendations are that medications play a very limited role in the treatment of achalasia and should be used in very early stages of the disease, temporarily before more definitive treatments, or for patients who fail or are not candidates for other treatment modalities with strong evidences (level 4+) according to the GRADE system [44].

9.3.2 Botulinum Toxin

Botulinum toxin is a potent neurotoxin that inhibits the release of acetylcholine at presynaptic terminals of motor neurons. It is endoscopically injected into the LES in the four quadrants [49]. Botulinum toxin has been used as diagnostic and therapeutic purposes. In children, the dose and the timing of injection frequency have not been well defined. Its effect is temporary, and the mean duration of symptom relief is 4 months in children, thus requiring repeated treatments [50]. In the 2014 Cochrane database, 80 % of patients experienced an immediate relief of their symptoms, but the recurrence rate was 60 % within a year [47, 51]. In the SAGES statements, 85 % of patients were initially improved, but the effect diminished over time (50 % at 6 months and 30 % at 1 year), and universal symptomatic relapse occurred at 2 years [44]. In case of failure, these patients need surgical treatments. They are the most difficult cases for the surgeons as the inflammation induced by the toxin evolves toward a fibrosis between the mucosa and the muscular layers with a subsequent increased risk of perforation [43, 44].

9.3.3 Dilatations

The aim of dilatations is to mechanically enlarge the LES. This can be done either using pneumatic dilatations or with bougies as the Savary-Gilliard bougies (M. Savary was our Chief of ENT in Lausanne, Switzerland) under general anesthesia in children. Both are endoscopically placed over a guidewire under fluoroscopic guidance. In both techniques, even under view control, passing the LES with the guidewire can be difficult in those cases where it is firmly tight. When using balloon dilatators, a radial pressure is performed on the LES that some authors thought to be better than a longitudinal direction of dilatations as done with the other method. When using balloon dilatations, it can be difficult to control the strength of expansion when the balloon inflates suddenly. For this reason, Savary’s technique is softer and more progressive. Our belief is that all different techniques should be available and adapted to each case and dilatation. Multiple dilatations are often required [52]. The choice of dilator size is based on the size of the child. The sizes range from 12 to 35 mm [6, 45, 53, 54] The greater number of sessions per child varies from two to five [45].

Dilatations bear an immediate risk of perforation estimated at 2.4 % (0.5–5.6 %) [53, 55, 56], and 50 % or more of these patients with perforations required emergency surgery [57]. In addition, the release of the LES may induce a gastroesophageal reflux disease (GERD).

In the Cochrane database (children and adults), the initial release of symptoms was 70 %, and 40–50 % of patients remained asymptomatic after a year and several dilatations [47]. Hamza has reported a 90 % success rate in children treated with multiple pneumatic dilatations [54]. After dilatations, 61 % of patients were asymptomatic at 5 years of follow-up and 47 % at 10 years [55, 56]. These results are worse than those after surgery (see below). No long-term follow-up studies after dilatations are available for children. The advantages of dilatations are a shorter length of stay and decreased costs [53].

Many adult studies compare the effects of dilatation with laparoscopic Heller myotomy (LHM), with an advantage for the surgery on short- and long-term follow-up [57, 58]. The same results have been reported in pediatric series [6]. Some authors advocate for dilatations in older children suffering achalasia as safe and effective initial treatments thus avoiding surgery [53, 54, 59]. However, surgery after dilatations has an increased risk of perforation due to scarring adhesions between the mucosa and the muscle layers, not as high as after botulinum toxin but higher than if done as a first procedure.

The SAGES recommends dilatations as the most effective nonoperative treatment. However, it is associated with the highest risk of complications. It should be considered in selected patients who refuse surgery or are poor operative candidates with strong evidences (level 4+) according to the GRADE system [44].

9.3.4 Peroral Endoscopic Myotomy (POEM)

POEM is a new endoscopic technique for achalasia introduced by Inoue in 2008 [60]. It is one of the applications of the natural orifice transluminal endoscopic surgery (NOTES) concept. Under endoscopic vision, a mucosal incision is performed ≈ 15–20 cm above the LES. Then a submucosal tunnel is done downward to allow an endoscopic section of the muscular layers. At the end of the procedure, endoscopic clips are placed on the mucosal wound. To date, more than 3000 patients have been operated, and the number of publications is increasing. Some small pediatric and adolescent series have been reported, all but one including less than ten cases [61–64], the latest with 27 cases [65]. The youngest operated child was 3, suffering severe growth retardation, achalasia, and Down’s syndrome [66]. Li gives a detailed description of the pediatric procedure with references for the equipments [63]. The selected cases had no previous treatment, and the reported problems are related to firm adhesions between the mucosa and the muscle. Caldaro has published a comparative study in children receiving nine LHM vs nine POEM with no conclusive results, but the series is very small [62].

In adults, there are 16 % reported minor complications and 3 % severe but nonfatal, as to mention: emphysema, pneumothorax (0.2 %), pneumoperitoneum (8.3 %), bleedings (1 %), leaks 0.2 %, and prolonged hospital stay >5 days (1 %) [67].

The results seem good with 82–100 % immediate relief of symptoms, but the longest follow-up published is 16–24 months [67–69]. The mean GERD rate is 35 % (limits 15–46 %). In the pediatric series by Chen, during the follow-up period of 24 months, 19.2 % patients develop a GERD [65]. A randomized study with a 6 months follow-up reports no difference between LHM and POEM [67]. However LHM has been shown to provide more durable symptom relief [70] and additionally could result in less post-intervention GER [71].

9.3.5 Surgeries

9.3.5.1 Heller Myotomy

The Heller myotomy is performed today doing an anterior incision of the muscular layers of the esophagus, approximately 5 cm above the esophagogastric junction and carried onto the gastric wall by 2–3 cm. Laparoscopic Heller myotomy (LHM) is the treatment of choice in adults and in children giving advantages of less pain, better cosmesis, shorter hospital stay, and faster return to normal activity [37, 43, 59, 72–74]. A survey concerning 64 pediatric centers worldwide done by Myers in 1994 could only conclude that “cardiomyotomy performed by the abdomen gives best results” [75]. The highly debated point is whether it is necessary or not to add a fundoplication to reduce the occurrence of iatrogenic GERD.

The HLM in children is performed under general anesthesia. We set the child supine at the foot end of the table, the legs being wrapped in the “frog position” for infants or extended on stirrups, with the knees slightly flexed by 20–30° in children and adolescents. The table is tilted to a 30° reverse Trendelenburg position. The surgeon stands at the foot of the table, facing the hiatus. A transumbilical port is inserted according to the Hasson technique for a 5 mm × 30° angulated telescope. We work with three ports (3 or 5 mm according to the age), the right upper one for an atraumatic liver retractor and the two remaining ones for the working instruments. The cardiophrenic membrane is opened anteriorly. The anterior face of the esophagus is freed by 5–8 cm according to the patient’s size. The anterior vagus nerve is identified and mobilized so that the myotomy can be done high up on the esophagus beneath the nerve. We do not dissect the esophagus posteriorly, so we do not surround the esophagus with a traction loop. Traction is applied on the stomach below the esophagogastric junction using a Babcock clamp, to expose the anterior part of the distal esophagus. The myotomy is started on the esophagus just above the gastroesophageal junction with an incision in the anterior muscular wall down to the mucosa. Usually the mucosa separates easily from the muscular layers, if there have been no previous treatment with botulinum toxin or dilatations. The muscular section is done according to the surgeons’ preference with scissors, with a monopolar hook, with a sealing-cutting device (LigaSure® LS 1500 Dolphin Tip or Maryland laparoscopic instrument by Covidien), or with a harmonic dissector (Ultracision® by Ethicon). A great care should be taken to lift up the muscle from the mucosa when using a monopolar hook or a harmonic dissector as those instruments heat and can perforate. The muscular incision must be undertaken down on the anterior face of the stomach by 2–2.5 cm. The transition from esophageal to gastric muscle fibers can be seen as they change from a horizontal circular orientation to an oblique one and are more adhered to the mucosa. This ensures having been enough downward. It is mandatory to check the integrity of the mucosa after the myotomy. This can be done using instilled water, air, or methylene blue in the esophagus at the level of the myotomy or better, as we do, performing a peroperative endoscopy for both perforation and adequacy of the myotomy. In case of a tear in the mucosa, an attempt of suture can be done, and we leave a suction probe at the level of the leak for a few days. Then according to the surgeon’s preferences, an anti-reflux wrap can be built.

Antibiotics are not given routinely. Without perforation, the child is orally fed in the operative day or the next one. Some authors perform systematically an UGI to check the integrity of the esophagus before discharging the child [9, 37]. We do not.

The Cochrane review and other studies report good initial results after LHM, with 88–97 % relief of symptoms [44, 47, 51, 76]. This improvement appears to be long lasting. However, 79 % of patients remain asymptomatic after 5 years of follow-up and 76 % at 10 years [44, 55, 56].

Complications of surgery are related to perforations and GERD. Perforation rates occur from 0 to 15 % in large series [72, 77, 78]. Most of them heal spontaneously if recognized. In their comparative adult series, Weber and Chen have evidenced a higher risk of perforation with LHM (4.8 %) than with dilatations (2.4 %). However it should be noticed that the rate of reoperations was far smaller in the LHM group (0.6 %) than in the dilatation (2.4 %) as most of the perforations due to dilatations have been ignored whereas the one done under LHM are immediately identified and treated [55, 56].

The rate of perforation rises significantly during a redo procedure ranging from 4.7 to 30 % [58]. Several studies have suggested an increased risk of perforations during LHM up to 28 %, after previous endoscopic treatment (botulinum toxin or balloon dilatations). Reversely, other studies found no association between preoperative endoscopic treatment and perforations. The warning from the SAGES is that previous endoscopic treatment for achalasia may be associated with higher myotomy morbidity, but the literature is inconclusive. Then a careful approach by an experienced team is advisable [44].

9.3.5.2 Anti-reflux Procedures

A fundoplication can be added to prevent GERD following Heller myotomy. Whether it should be done, and with which wrap, is one of the most debated points among surgeons. Several authors don’t believe it necessary, including in children [72, 79]. If done, several anti-reflux procedures can be used: a total fundoplication (loose 360° Nissen) [77, 80], a partial posterior 270° wrap (Toupet) [57, 81], or an anterior 180° wrap (Dor or Thal) [6, 37, 43, 74].

Several adult studies have compared the LHM with and without anti-GER procedure with an advantage for the combined procedure summarized by Tsuboi [57]. The 2012 guidelines of the SAGES also strongly recommended a combination of laparoscopic myotomy with anti-reflux surgery [44]. They did not precise which type of procedure is the best, as long as it is a partial one. The circular fundoplication (i.e., the Nissen) should be avoided because of the risk of persistence and/or recurrence of the disease.

The most efficient anti-GER is the Nissen. However, even a loose Nissen applies a pressure on an LES that we wanted to release [9, 72]. When doing a Toupet, the two rows of stitches of the 270° wrap are tied to the edges of the myotomy. Those who advocate for a Toupet believe that it helps to keep the myotomy open. On the other hand, a Toupet leaves the anterior mucosa exposed without coverage. Finally, both the Nissen and the Toupet require posterior dissections of the hiatus, which is not the case with an anterior wrap that preserves the periesophageal ligaments. In addition the anterior wrap protects the uncovered esophageal mucosa.

In a randomized controlled study on 144 adult patients followed up during 125 months, Rebecchi determined that laparoscopic Dor fundoplication after a LHM was superior to Nissen fundoplication because the recurrence rate of dysphagia was significantly higher in patients who received a Nissen fundoplication (15 %) than a Dor (2.8 %) [80]. However, as Franklin we wonder if recurrence of the dysphagia is a failure of the surgical treatment or is related to the nature of disease [37]. A pediatric multicenter prospective study, published by Rawlins and involving 85 children followed up for 36 months, compared LHM and Dor or Toupet showing no difference of the De Meester scores at pH-metries performed 6 and 12 months postoperatively. The conclusion was that “LHM provides significant improvement in dysphagia and regurgitation symptoms in achalasia patients regardless of the type of partial fundoplication” [82].

Laparoscopic surgery for esophageal achalasia provides symptomatic improvement, but some patients have a poor outcome. It can be related to the surgery (insufficient myotomy, too tight wrap, too lose wrap with subsequent esophagitis) thus requiring redo procedure. Esposito suggested that the experience contributes to decrease the rate of complications since their incidence of postoperative dysphagia dropped from 50 to 16 % with further experience [74]. Patients with severe preoperative dysphagia, aperistalsis, or esophageal dilatation have greater risks of a poor outcome [81]. Favorable factors in adults are the short duration of the symptoms without previous use of botulinum toxin [83]. An initial LES pressure >35 mmHg had more than 21 times the likelihood to achieve excellent dysphagia relief after myotomy as compared with those with an LES pressure ≤35 mmHg [84].

High-resolution manometry (HRM) has evidenced that there might be several types of achalasia and esophageal dysmotility including in children who may have primary dysmotility and “partial” achalasia [28, 32, 47]. To date, no investigation has a predictive value. However, several studies have evaluated the treatment outcome by type on HRM. The analysis found that Type II had the greatest therapeutic response (95.3 %), followed by Type I (85.4 %), and then Type III (69.4 %) [32, 85–87]. Thus, possibly Type III is another misunderstood form of the disease for which a new treatment should be developed. Very recently Sodikoff has reported a correlation between HMR types of achalasia and the immunohistological findings on surgical biopsies of the muscularis propria obtained from 46 patients during LHM [27].

9.4 Long-Term Follow-Up and Cancer

Chronic irritation of the esophageal mucosa increases the risk of squamous cell carcinoma and/or adenocarcinoma. Long-lasting achalasia increases 16 times the risk of developing a cancer. Due to residual GERD and poor peristalsis, the risk persists even after (surgical) treatment [88]. The risk of both squamous cell carcinoma and adenocarcinoma of the esophagus is believed to be significantly increased in patients with achalasia; however the absolute excess risk is small [89]. Leeuwenburgh has statistically evaluated the risk of cancer in non-treated achalasia vs treated by dilatations. The conclusion was that Barrett’s esophagus is incidentally diagnosed in untreated achalasia patients despite high LES pressures but is more common after successful treatment, especially in the presence of hiatal hernia. Patients treated for achalasia should be considered for GERD treatment and surveillance of development of Barrett’s esophagus, in particular, when they have low LES pressures and a hiatal hernia [90]. Thus, some authors recommend to perform repeated endoscopies since the second decade [76]. However, given limited data and conflicting opinions, it is unknown whether consensus regarding screening practices in achalasia among experts exists. Ravi created a worldwide survey distributed to 28 experts to assess screening practices in achalasia. While 82 % of experts endorsed long-term follow-up of patients, no consensus was found regarding its timing [91].

Conclusions

The pathogenesis of esophageal achalasia is not elucidated, and the pathogenic mechanism is not understood. Many questions remain unanswered. We don’t know why we have a depletion of ICC and could this possibly be responsible for the lack of LES relaxation, because of missing inhibitory neurotransmission. Does achalasia in children differ from adults? Are biopsies with c-Kit staining of predictive value? The answers to these questions will help to promote optimal treatment in the future. At the moment, the LHM has become a good option for the treatment of achalasia. It gives symptomatic improvement to the majority of patients but not complete resolution of their disease.