State-of-the-Art Surgery in Achalasia

Achalasia is a chronic neurodegenerative disease of the esophagus caused by a demise of intramural motoneurons of the esophageal wall. As a result, the failure of central mononeural inhibition of the myenteric plexus results in abnormal esophageal motility including hypocontractile, missing or hypercontractile peristalsis, as well as an impaired relaxation of the lower esophageal sphincter (LES) with continuous spasm of the LES. Typically, the disease starts in the area around the LES and can finally proceed affecting the entire esophagus [1]. The exact reasons for the pathological alteration are still unknown. However, it is believed that genetic predispositions might lead to an increased susceptibility toward environmental triggers, such as viral infections [1‒3]. As a result, an imbalance between inhibition and excitation on the one hand, and neural cell impairment or death on the other hand causes the classical symptoms of achalasia, such as dysphagia, regurgitation, retrosternal pain or spasms, and consecutive weight loss. The Eckardt score [4] has become a reliable clinical scoring system not only for the evaluation of symptom severity during the initial diagnosis but also in the course of any type of therapy. The intensity of each of the four achalasia cardinal symptoms (dysphagia, retrosternal pain, regurgitation, weight loss) is assessed and totaled. The Eckardt score can therefore range from a minimum of 0 (= no symptoms) to a maximum of 12 points (= strongest expression), depending on the intensity of the individual symptoms [4].

Achalasia is a rare disease. Its incidence and prevalence increase with age, and it is not uncommon that several years can pass between symptom onset and first diagnosis of achalasia [5]. Therefore, both diagnosis and treatment should be localized in dedicated centers who have much experience.

Although the diagnostic methods have developed during the past, now including high-resolution manometry (HR manometry), (timed barium) esophagogram, upper gastrointestinal endoscopy, multiple rapid swallow response, and Endo-FLIP measurement [1], there is often a long delay between occurrence of first (possibly slight) symptoms and the final diagnosis of achalasia, resulting in long medical history before being referred to specialized centers [6, 7]. Based on HR manometry, the Chicago classification [8] distinguishes between the following types of achalasia:

• Type I with complete aperistalsis of the tubular esophagus.

• Type II with (pan-)esophageal compression.

• Type III with spastic contractions of the esophagus.

Types I and II are the predominant variants of achalasia. However, type III is rather rare, represented by about 8% of all patients only. It is, thus, challenging for all modalities of therapeutic approaches, as often affecting the entire esophagus.

According to the European Guidelines on achalasia [9], the diagnostics may be extended in case of putative risk factors for malignant pseudo-achalasia, such as age >55 years, duration of symptoms <12 months, weight loss >10 kg, or severe difficulty passing the LOS with a scope. In these cases, additional imaging including computer tomography or endoscopic ultrasound should be further performed.

The treatment of achalasia is a clinical complex act of defiance for both, the patient and the practitioner, and always demands an individualized therapeutic (“tailored”) approach. Pharmacological intervention aims to relax the esophageal smooth muscles via application of calcium antagonists, nitrates, or phosphodiesterase inhibitors. Most patients will most likely reject the permanent therapy with these medications in the long run, either fearing adverse side effects or being dependent on the medication for their entire life. This is true especially for younger patients. In concordance with the European Guidelines, the pharmacological treatment of achalasia is not recommended, being vastly ineffective [9].

Endoscopic-interventional therapies include botulinum toxin (BoTox) injection into the LES, pneumatic dilatation (PD), and peroral endoscopic myotomy (POEM). These topics are discussed in other articles in more detail. BoTox injection and PD lead to temporary effects of LES relaxation only and have to be repeated in shorter or longer intervals. BoTox injection is furthermore applied for diagnostic reasons only (e.g., when achalasia is primarily diagnosed) and is not considered to be a valid mid- to long-term option. Recent data from a multicenter randomized control trial suggest that the long-term results of PD are comparable to surgical treatment of achalasia via laparoscopic Heller myotomy (LHM) [10]. It is important that a relatively large group of patients refused repeated endoscopic interventions and re-dilatation and that there is the relevant risk of perforation during or after PD.

The POEM procedure has become another widely used approach in the context of achalasia therapy. Nowadays, this interventional procedure has become the established standard, especially for patients with type III achalasia, avoiding “classical” surgery in the majority of patients [11‒13]. Long-term data from both single-center and multicenter analyses demonstrate that POEM results in prolonged reduction of achalasia-associated symptoms in those patients and high patient satisfaction [14‒16]. Compared to surgical procedures, such as LHM or RHM, the rate of gastroesophageal reflux after treatment is significantly higher after POEM. A large meta-analysis including 53 studies with 5,834 LHM patients versus 21 studies with 1,958 POEM patients showed higher rates of GERD confirmed by endoscopy after POEM as compared to LHM [17]. Similar results were found by screening with the method of pH monitoring after POEM [17]. Another recently published single-center analysis revealed the occurrence of objective GERD after POEM in about 51% of patients and the prevalence of even severe GERD in 19% of this cohort [18]. The authors were not able to identify predictors for the development of postinterventional GERD since the length of the POEM-myotomy did not affect GERD occurrence. Interestingly, one quarter of patients with objective GERD did not suffer from symptoms, and as expected, obese patients showed more reflux.

Depending on the subtype of achalasia, the following tailored approaches can be summarized [1]: type I achalasia can be treated by PD, POEM, or LHM as initial procedures. The same holds for type II achalasia. Contrary, type III achalasia is increasingly the domain of POEM since the elongated hyperperistaltic esophageal wall has to be incised over a long distance, accordingly. Alternatively, surgical treatment with a long myotomy is an optional approach in these patients. BoTox injections can be applied as a bridging strategy or if patients are functionally not suitable for surgery due to comorbidities. In conclusion, according to our own clinical practice at our specialized department, the subgroup of patients who benefit most from surgery can be characterized as follows:

• Patients younger than 40 years with type I or II achalasia.

• Patients with repeated (>3x) PD and/or BoTox injection and persistent or recurrent symptoms.

• Risk patients of PD with increased danger of perforations.

• Patients who wish definitive surgical treatment.

Therapeutic success can be assessed repeatedly via the Eckardt score and should be ≥3 (during a minimum of 6 months following surgery [or other therapeutic modalities]). Accordingly, remission score according to Eckardt is 0 (no change of Eckardt score), I (slight change), II (minimal change of 1 Eckardt stage), 3 (<Eckardt stage I and II), or 4 (symptom-free for more than 6 months).

The “extramucosal cardioplasty in chronic cardiospasm” technique described by Ernst Heller (surgeon from Leipzig, Germany) in 1913 and modified by Zaaijer in 1923 consists of splitting the high-pressure zone of the lower esophagus and applying a partial fundus cuff as reflux protection [19]. In total, the surgical procedure can be subdivided into 5 distinctive steps:

• 1.

  Dissection of the hiatus and mediastinal preparation/mobilization under protection of the vagal nerves. The anterior vagal nerve is protected by avoiding diathermia during this step of preparation. In case that it does not become visualized during the surgical procedure, we avoid to actively expose the nerval structures so that no damage is caused by preparation.

• 2.

  Dissection of the short gastric vessels of the fundus.

• 3.

  Slinging of the distal esophagus.

• 4.

  Esophageal myotomy (EM) of about 5–6 cm in length (beginning at the esophagogastric junction from aboral and proceeding to oral), followed by myotomy of the proximal fundus (at least 2.5–3 cm in length) with preparation from oral to aboral (see Fig. 1).

• 5.

  Antireflux plasty (180° anterior semifundoplication according to Dor vs. 270° dorsal fundoplication according to Toupet) (→ the underlying disease implies that a 360° Nissen wrap is never indicated!) (see Fig. 2). Fixation of the two most cranial stitches of the fundoplication of both sides of the myotomy to the esophagus and the diaphragm to avoid telescoping of the fundoplication (“slippage” of the wrap).

In the literature, 180° anterior semifundoplication according to Dor has been described as a standard antireflux plasty in combination with Heller myotomy [20‒23], and only few data exist comparing the choice of optimal antireflux procedure after laparoscopic cardiomyotomy. However, in 2017, a study including 37 patients (Toupet) versus 60 patients (Dor) with surgery for achalasia described that patients after Dor showed significantly more often reflux-associated symptoms, such as heartburn as compared to those after partial fundoplication according to Toupet [23]. Nevertheless, the majority of all patients (88%) was satisfied with their individual surgical outcome and did not suffer from increased reflux. However, there is no clear recommendation, which antireflux procedure is significantly better.

The initial open surgical technique has now been replaced by the LHM, which has further been evolved to the robotic approach (RHM). However, apart from the different access routes, the surgical technique is the same in all three approaches. Due to its good long-term results and low complication rates, LHM has become first-line treatment for achalasia, particularly in younger patients (≤40 years). It can also be applied in terms of a “rescue” procedure in patients with previous unsuccessful or failed PD [24, 25], BoTox therapy, or POEM [26‒30] with good results.

POEM can be performed as both posterior or anterior myotomy, resulting in equal results for achalasia patients [31‒33]. However, recent data suggest that posterior POEM is associated with fewer adverse events (such as perforation) and a shorter incision closure time [31]. In concordance to this, a posterior POEM myotomy can be combined with an anterior LHM or RHM without any interferences to the previous endoscopic intervention of POEM and consecutive low surgical trauma in terms of adhesiolysis. Especially patients with type I or II achalasia benefit from LHM or RHM [24, 34]. Overall, LHM is a safe procedure with a mortality rate of 0.1%. The main risk is a lesion of the vagal nerves or its branches, resulting in delayed gastric emptying or pylorospasm, which demands thorough visualization and preservation of the nerve during the whole surgical procedure. Another possible, but rather rare, complication during LHM or RHM is the perforation of the entire wall of the distal esophagus or the proximal fundus. According to literature, this may occur in 5–7% of all surgical cases (especially during the “learning curve” of inexperienced surgeons). However, its clinical significance becomes obvious in 0.7% only, as such injuries can easily be detected during the procedure and then be treated with additional sutures and later be covered by the fundic wrap. To avoid a postsurgical stenosis due to incomplete myotomy or due to tight reconstruction of the LES via fundoplication, it is advisable to splint the distal esophagus with a thick gastric bougie during the operation. This also facilitates the mobilization of the esophagus. In our own hands, the 38 French bougie has proven help and successful with regard to preventing narrowing of the distal esophagus or esophagogastric junction.

The minimal-invasive myotomy according to Heller has recently also been performed robotically (RHM) with respectable success. The putative advantages are the angulation of the surgical instruments with a better angle during the myotomy, lower rates of intraoperative mucosal laceration, and increased visualization of the muscle layers of the high-pressure zone of the distal esophagus [35‒37]. Nevertheless, long-term data or prospective randomized studies on robotic myotomy are still pending.

So far, only few retrospective monocentric studies (inclusive own data) comparing LHM with RHM have been published demonstrating comparable results considering the postsurgical symptomatic relief and an improvement of the Eckardt score [38‒40]. The rates of intraoperative mucosal perforations seem to be lower in RHM [38, 40], while there are contradictory statements considering the length of hospital stay ranging from no differences between LHM and RHM [39, 40] to shorter hospital stay in favor for RHM [38].

A meta-analysis published in 2024, including studies between January 2010 and November 2022, drew similar conclusions [41]: the length of hospital stay was nonsignificantly shorter and patients had fewer conversions from minimally invasive to open surgery, as well as lower intraoperative perforation rates [41].

After initial treatment of achalasia, two different types of recurrence can be differentiated: type I recurrence (“pseudo-recurrence” or persistent achalasia) is a result of previous incomplete myotomy, which consecutively makes re-myotomy with lengthening of the myotomy necessary, mostly at its distal edge, while type II recurrence is the progression of the underlying disease to sigmoid-shaped megaesophagus (>6 cm in diameter). It can only be treated as ultima ratio by subtotal esophagectomy and reconstruction via gastric pull-up or colon interposition.

Nevertheless, it has to be clear that every “persistence” or “recurrence” after a previous therapeutic intervention always (!) has to lead to a “de novo” full diagnostic workup to identify the underlying problem resulting in treatment failure. For persistent achalasia symptoms and ongoing dysphagia (type I “recurrence”) after previous LHM/RHM, we apply a tailored approach following the algorithm in our own clinical practice:

• 1.

  As method of first choice, an attempt of PD or POEM can be tried. However, this does not hold for cases with a tight wrap narrowing the esophagogastric junction, which in most patients demands resurgery.

• 2.

  In case of failure of an endoscopic attempt, in the next step resurgery and elongation of the previous anterior myotomy – either laparoscopic or robotic – in combination with Dor’s or Toupet’s partial fundoplication should be addressed. In most patients, the myotomy at the distal esophagus or the cardia has to be lengthened. Alternatively, in cases of severe scar development of the anterior myotomy and risk of further intraoperative damage through exploration, resurgery with posterior additional myotomy can be recommended in cases without previous POEM and known adhesions between dorsal esophagus and aorta. This approach, however, increases the risk of posterior vagal nerve damage and the occurrence of postsurgical reflux.

GERD due to pathological reflux after POEM with development of severe mucosal damage or peptic stenosis of the distal esophagus can also be a further indication for additional surgery in achalasia. Typically, in our clinical routine, hiatoplasty in combination with Dor’s or Toupet’s partial fundoplication can be applied to reconstruct the angle of His and the LES pressure zone.

After failure of both, endoscopic interventions (PD, POEM) or surgery (LHM/RHM), and continuous progression of achalasia with development to sigmoid-shaped megaesophagus (type II “recurrence”), therapy-refractory esophageal strictures or an invasive esophageal cancer, the Ivor Lewis (intrathoracic anastomosis) or McKoewn (cervical anastomosis) esophagectomy might be – from our point of view – the only most meaning and successful option, as described in the literature [42, 43]. Indication for resection surgery and reconstruction by gastric pull-up or colon interposition in these cases, however, has to be evaluated carefully, in order to weigh the possible advantages and disadvantages of a more radical procedure in a principally benign disease.

One aspect of the future therapy of achalasia is the further understanding of the disease’s molecular genetic subtypes and their correlation with “conventional” clinical diagnostics, such as HR manometry. In this way, more and more individualized therapy concepts (PD, LHM/RHM, POEM) might result and myotomy lengths (in LHM/RHM, POEM) could be adjustable to those findings. Furthermore, progressive development in both robotic surgery and endoscopy (such as the EndoQuest device), as well as an increased expansion of this technology in the specialized centers will improve the already good surgical results of the procedures. Accompanied by innovative intraoperative imaging (such as hyperspectral imaging) for better identification of risk structures (e.g., the vagal nerves), surgery has the potential to become the first approach in achalasia instead of being merely one primary alternative treatment option.

The authors have no conflicts of interest to declare.

There was no funding for the current work.

Conceptualization and literature research: P.S.P. and I.G.; clinical case research and image configuration: S.N.; manuscript writing: P.S.P.; manuscript editing: S.N. and I.G.; and manuscript review: P.S.P., S.N., and I.G.