Long-term outcomes of peroral endoscopic myotomy with simultaneous submucosal and muscle dissection (POEM-SSMD) for achalasia with severe interlayer adhesions
Achalasia is a rare esophageal motility disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absent peristalsis in the esophageal body. Peroral endoscopic myotomy (POEM) has emerged as a minimally invasive treatment option for achalasia, offering significant symptom relief and improved quality of life (QoL). However, severe interlayer adhesions between the submucosal and muscular layers of the esophagus pose a significant challenge to the conventional POEM procedure, often leading to aborted interventions. To address this issue, a modified technique called POEM with simultaneous submucosal and muscle dissection (POEM-SSMD) was introduced in 2014. This study reports the long-term outcomes of POEM-SSMD in a cohort of 22 patients with severe interlayer adhesions, providing valuable insights into its efficacy, safety, and impact on QoL.
Background and Rationale
Conventional POEM involves the creation of a submucosal tunnel to access and dissect the muscular layers of the esophagus, thereby relieving the obstruction caused by achalasia. However, in cases of severe interlayer adhesions, the submucosal tunnel cannot be adequately established, rendering the procedure ineffective. POEM-SSMD was developed to overcome this limitation by simultaneously dissecting the submucosal and muscular layers, allowing for successful myotomy even in the presence of adhesions. Short-term follow-up studies have demonstrated significant symptom improvement with this technique, but long-term outcomes remained unexplored until this study.
Study Design and Patient Characteristics
This retrospective study included 22 patients with severe interlayer adhesions who underwent POEM-SSMD at the Chinese People’s Liberation Army (PLA) General Hospital between December 2014 and May 2019. The cohort consisted of 15 males and 7 females, with an age range of 19 to 76 years (mean age: 49.8 years). All patients were diagnosed with achalasia based on clinical symptoms, esophagogastroduodenoscopy (EGD), barium swallow, and high-resolution manometry (HRM). The severity of symptoms was assessed using the Eckardt score, which evaluates dysphagia, regurgitation, retrosternal pain, and weight loss. Thirteen patients (59%) had a history of prior treatments, including Botox injection, balloon dilation, POEM, or laparoscopic Heller myotomy (LHM).
Procedure Details
The POEM-SSMD procedure was performed by experienced endoscopists with over 5 years of POEM experience. The specific steps were as follows:
- Submucosal Injection and Tunnel Entry: A submucosal injection was performed to create a liquid cushion, followed by an inverse T-shaped incision to establish the tunnel entry site.
- Submucosal Tunnel Extension: The submucosal tunnel was extended as far as possible until severe interlayer adhesions prevented further progression.
- Simultaneous Submucosal and Muscle Dissection: A 1–3 cm full-thickness myotomy was performed after establishing a short tunnel. The submucosal and muscular layers were incised simultaneously to 2–3 cm below the esophagogastric junction (EGJ), while preserving the mucosal integrity.
- Mucosal Closure: The mucosal incision was sutured using metal clips after ensuring complete hemostasis and endoscopic passage through the cardia.
Perioperative Management and Adverse Events
Postoperative care included fasting for 3 days, followed by a gradual transition from a clear liquid diet to a normal diet over 4 weeks. Intravenous proton pump inhibitors (PPIs) and antibiotics were administered during the nil per os (NPO) period, followed by oral PPI therapy for at least 1 month. Routine imaging (X-ray or CT) was performed to monitor for gas-related adverse events such as subcutaneous emphysema or pneumothorax. Patients were also monitored for delayed hemorrhage, mucosal perforations, infections, and other complications.
The mean operation time was 62.3 minutes (range: 23–130 minutes). The median length of the submucosal tunnel was 7.0 cm (range: 2–12 cm), and the mean length of the myotomy was 5.5 cm (range: 3–8 cm). The median hospitalization duration was 7 days (range: 5–12 days). Minor adverse events included mild to moderate substernal pain in six patients (27%), which resolved spontaneously, and a small amount of pleural effusion in one patient, which was absorbed without intervention. Neck subcutaneous emphysema occurred in two patients (9%) and resolved spontaneously. Cardia mucosal penetration occurred in three patients (14%) and was successfully managed with fibrin sealant and metal clips. Postoperative fever was observed in four patients and resolved with antibiotic treatment.
Long-term Outcomes
Four patients were lost to follow-up, leaving 18 patients for long-term evaluation. The mean follow-up period was 28.7 months (range: 10–63 months). Clinical success, defined as an Eckardt score ≤ 3 at the last follow-up without the need for Re-POEM or additional treatment, was achieved in 15 patients (83.3%). The median Eckardt score decreased significantly from 6.5 (range: 4–11) preoperatively to 1 (range: 0–6) postoperatively. Postoperative manometry was performed in five patients, demonstrating a significant reduction in lower esophageal sphincter pressure (LESP).
Quality of life (QoL) was assessed using the AE-18 health-related QoL scale, which comprises 18 items with a maximum score of 90 points. Sixteen patients (89%) showed improved QoL scores during follow-up. The median AE-18 total score increased from 69 (range: 54–79) preoperatively to 87 (range: 67–89) postoperatively. Two patients developed reflux esophagitis (Los Angeles classification B and C), and altered esophageal acid exposure was detected in one patient via 24-hour pH monitoring. Symptomatic reflux, defined by a GerdQ total score ≥ 8, was observed in six patients (33%).
Discussion
POEM-SSMD represents a significant advancement in the treatment of achalasia with severe interlayer adhesions. By enabling simultaneous dissection of the submucosal and muscular layers, this technique overcomes the limitations of conventional POEM and provides a viable treatment option for patients who would otherwise be ineligible for endoscopic intervention. The long-term outcomes of this study demonstrate the efficacy and safety of POEM-SSMD, with an 83% clinical success rate and significant improvements in QoL.
The procedure’s safety profile is also noteworthy, with a low incidence of gas-related adverse events (9%) and mucosal penetration (14%), all of which were managed conservatively. The clinical reflux adverse event rate was consistent with that reported for conventional POEM, underscoring the feasibility of POEM-SSMD as a treatment option.
Limitations
This study has several limitations. First, it is a retrospective, single-center analysis without a control group. Second, paired HRM results were unavailable for 17 patients, limiting the ability to assess changes in esophageal motility comprehensively. However, the significant reduction in Eckardt scores and improvement in QoL scores provide robust evidence of the procedure’s efficacy. The mean follow-up period of 28.7 months, while substantial, warrants caution in interpreting long-term outcomes.
Conclusion
POEM-SSMD is a safe and effective treatment option for achalasia patients with severe interlayer adhesions. It offers significant symptom relief, improves QoL, and has a favorable safety profile. The technique enriches the concept of super minimally invasive surgery (SMIS) and provides a valuable alternative to conventional POEM and laparoscopic Heller myotomy (LHM). Further prospective, multicenter, randomized trials are needed to validate these findings and establish POEM-SSMD as a standard treatment for this challenging patient population.
doi.org/10.1097/CM9.0000000000001971
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