Introduction
Achalasia is a primary esophageal motor disorder, typically of unclear etiology. The
disorder is characterized by degeneration of the myenteric plexus resulting in impaired
relaxation of the esophagogastric junction and loss of organized peristalsis in the
esophageal body causing patients to experience dysphagia, esophageal dilation, food
accumulation, and regurgitation [1]. Achalasia is a rare disease with a globally reported incidence varying from 0.03
to 1.63 per 100 000 persons per year [2]. Treatment options include pharmacotherapy using muscle relaxants, endoscopic injection
of botulinum toxin, pneumatic balloon dilation, and laparoscopic Heller myotomy (LHM)
[3]. Peroral endoscopic myotomy (POEM) is a novel and minimally invasive therapeutic
modality for achalasia and related disorders, which was first reported by Inoue et
al. in 2010 [4]. While studies have shown POEM to be as safe and effective, with shorter recovery
times and fewer serious complications compared with LHM [5]
[6], guidelines suggest that both modalities are comparable treatment options for management
of patients with achalasia types I and II [7].
Despite the clinical efficacy of POEM, postoperative symptomatic gastroesophageal
reflux disease (GERD) remains a major concern [8]
[9]. A study comparing outcomes of LHM and POEM found that at 3 months, 57 % of patients
in the POEM group and 20 % of patients in the LHM group had reflux esophagitis, as
assessed by endoscopy. The incidence at 24 months was 44 % and 29 %, respectively
[10]. While several studies have identified risk factors for post-POEM reflux such as
female sex, presence of preoperative esophagitis, as well as high preoperative Eckardt
score, the effect of procedural factors such as overall length of myotomy on post-procedure
reflux is debatable [11]
[12]. Based on the available evidence and following the tenets of LHM, the actual myotomy
length is recommended to be at least 6 cm (2 cm in the esophagus, 2–3 cm lower esophageal
sphincter, 2 cm cardia) and on average between 8 and 10 cm [13]. The length of the gastric myotomy and its effect on reflux has been reported in
the literature [14]
[15]. At present, the clinical relevance of esophageal myotomy length is not well known.
We performed a systematic review and meta-analysis of studies comparing outcomes of
short vs. standard myotomy length in patients with achalasia.
Patients and methods
Search strategy
The relevant medical literature was searched by a medical librarian for studies reporting
outcomes of short vs. standard myotomy in patients with achalasia. The search strategy
was created using a combination of keywords and standardized index terms. A systematic
and detailed search was run in November 2020 in Ovid EBM Reviews, ClinicalTrials.gov,
Ovid Embase (from 1974), Ovid Medline (from 1946 including epub ahead of print, in-process,
and other non-indexed citations), Scopus (from 1970), and Web of Science (from 1975).
Results were limited to English language only.
The full search strategy is available in Supplementary Appendix 1s. As the included studies were observational in design, the MOOSE (Meta-analyses Of
Observational Studies in Epidemiology) Checklist was followed [16] and is provided as Supplementary Appendix 2s. The PRISMA checklist [17] and PRISMA flow chart for study selection [18] were followed and are provided as Supplementary Appendix 3s and Supplementary Fig. 1s, respectively. Reference lists of evaluated studies were examined to identify other
studies of interest.
Study selection
In this meta-analysis, we only included studies that compared the clinical outcomes
of short vs. standard esophageal myotomy in patients with achalasia. Studies included
were randomized controlled trials (RCTs), cohort, and case–control studies that reported
outcomes of both treatment approaches. Studies were included irrespective of whether
they were published as full manuscripts or conference abstracts, performed in inpatient
or outpatient setting, follow-up time, and country of origin, provided they included
the appropriate data needed for the analysis.
Our exclusion criteria were as follows: 1) studies reporting outcomes of POEM in non-achalasia
disorders; 2) case reports and case series studies; 2) studies with sample size < 10
patients; 3) studies performed in the pediatric population (age < 18 years); and 4)
studies not published in the English language. In cases of multiple publications from
a single research group reporting on the same patient cohort and/or overlapping cohorts,
data from the most recent and/or most appropriate comprehensive report were retained.
The remaining studies were evaluated by two authors (S.C., D.R.) based on the publication
timing (most recent) and/or the sample size of the study (largest). In situations
where a consensus could not be reached, overlapping studies were included in the final
analysis and any potential effects were assessed by sensitivity analysis of the pooled
outcomes by leaving out one study at a time.
Data abstraction and quality assessment
Data on study-related outcomes from the individual studies were abstracted independently
onto a standardized form by at least two authors (S.C., S.R.K.). Authors (A.P., B.D.,
D.R.) cross-verified the collected data for possible errors, and two authors (S.C.,
S.R.K.) performed the quality scoring independently. We used the Newcastle–Ottawa
scale to assess the quality of cohort studies [19]. This quality score consisted of eight questions, the details of which are provided
in Supplementary Table 1s. For RCTs, we used the Cochrane Collaboration tool to assess risk of bias (Supplementary Appendix 4s) [20]. The quality of evidence was assessed using the Grading of Recommendations Assessment,
Development and Evaluation (GRADE) methodology and is depicted as per Supplementary Fig. 2s
[21].
Outcomes assessed
Patients were grouped based on the intervention they received: short esophageal myotomy
or standard esophageal myotomy. The following outcomes were assessed:
-
pooled odds ratio [OR] and proportion of clinical success (defined as postoperative
Eckardt score < 3 [22]
[23]
[24]
[25] or < 4 [26])
-
pooled OR and proportion of symptomatic postoperative GERD
-
pooled OR and proportion of postoperative erosive esophagitis as determined by endoscopic
evaluation
-
pooled OR and proportion of overall adverse events
-
pooled OR and proportion of mucosal injury in both groups
-
pooled means of length of hospital stay (LOS) in both groups.
Statistical analysis
We used meta-analysis techniques to calculate the pooled estimates in each case following
the methods suggested by DerSimonian and Laird using the random-effects model and
results were expressed in terms of odds ratio (OR) or mean difference along with relevant
95 % confidence intervals (CIs), when appropriate [27]. When the incidence of an outcome was zero in a study, a continuity correction of
0.5 was added to the number of incident cases before statistical analysis.
We assessed heterogeneity between study-specific estimates by using Cochran Q statistical
test for heterogeneity, 95 %CIs, and the I2 statistics [28]
[29]
[30]. Values of < 30 %, 30 %–60 %, 61 %–75 %, and > 75 % were suggestive of low, moderate,
substantial, and considerable heterogeneity, respectively. We assessed publication
bias qualitatively, by visual inspection of funnel plot, and quantitatively, by the
Egger test [31]. When publication bias was present, further statistics using the fail-Safe N test
and Duval and Tweedie’s “Trim and Fill” test was used to ascertain the impact of the
bias [32].
Given the low number of included studies, a Knapp–Hartung two-tailed P value of < 0.10 was considered statistically significant and R2
value was calculated to study the goodness-of-fit [33]. All analyses were performed using RevMan version 5 from the Cochrane collaboration
(Cochrane Collaboration, Copenhagen, Denmark) and OpenMeta [Analyst] software.
Results
Characteristics and quality of included studies
Five studies were included in the final analysis [22]
[23]
[24]
[25]
[26]. Two of the included studies were retrospective in design [24]
[25] and two were prospective RCTs [22]
[23]. One of the studies was published in abstract form, presenting interim analyses
[26]. Three studies were performed in China, one in Europe, and one in India. Based on
the Newcastle–Ottawa scoring system, both observational cohort studies were considered
to be of high quality (Supplementary Table 1s).
Search results and population characteristics
All search results were exported to Endnote where 5536 obvious duplicates were removed
leaving 4666 citations. Five studies with a total of 474 patients were included in
the final analysis. A schematic diagram demonstrating our study selection is illustrated
in Supplementary Fig. 1s.
A total of 214 patients underwent POEM with a short esophageal myotomy, ranging from
2.76 cm to 5 cm, and 260 patients underwent a standard esophageal myotomy, ranging
from 6.9 cm to 10 cm. Across all studies, the mean gastric myotomy length was kept
the same in both the short and standard groups, ranging from 2 cm to 3.2 cm [22]
[23]
[24]
[25]
[26]. Details of patient characteristics and demographics were available in all five
studies. A total of 238 males and 236 females were included in our analysis. The etiology
was Type I achalasia in 106 patients, Type II in 364 patients, and Type III in 4 patients.
Mean age ranged from 37.7 years to 49.3 years. LOS ranged from 2.81 to 9.9 days. Mean
follow-up time ranged from 8.09 to 26.8 months in the short myotomy group and from
8.3 to 29.5 months in the standard myotomy group.
Further details of patient characteristics, prior therapeutic interventions (botulinum
toxin, pneumatic dilation, and/or LHM) are described in [Table 1] and [Table 2].
Table 1
Study details – population characteristics.
|
Study [ref]
|
Design
|
Patients
|
Etiology (achalasia type)
|
Age, mean (SD) [range], years
|
Male/female
|
Disease duration, mean (SD) [range], years
|
Previous treatments
|
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
|
Li, 2019 [25]
|
Retrospective, Jan 2013–Dec 2016, single center, China
|
63
|
63
|
I 16, II 45, III 2
|
I 9, II 52, III 2
|
49.3 [19–79]
|
45.9 [16–72]
|
24/39
|
30/33
|
9.4 [0.1–40.0]
|
9.4 [0.3–30.0]
|
BD 13, Btx 8, HM 1, BD + Btx 1
|
BD 10, Btx 3, Stent 1, HM 1, BD + Btx 2, Btx + Stent 2
|
|
Huang, 2020 [24]
|
Retrospective, Jul 2011–Sep 2017, single center, China
|
36
|
74
|
I 12, II 24
|
I 26, II 48
|
40.8 (11.1) [16–68]
|
37.7 (13) [8–74]
|
19/17
|
40/34
|
8.8 (5.5) [2–25]
|
8.9 (5.8) [3–30]
|
BD 7, Btx 2
|
BD 9, Btx 3
|
|
Gu, 2020 [22]
|
Prospective, RCT, single blinded, Feb 2018–Feb 2019, single center, China
|
46
|
48
|
II 46
|
II 48
|
43.6 (11.4)
|
42.8 (10.2)
|
21/25
|
23/25
|
5.0 [0.3–34.0]
|
4.1 [0.3–31.0]
|
0
|
0
|
|
Nabi, 2020 [23]
|
Prospective, RCT, double blinded, Jun 2017–Mar 2019, India
|
34
|
37
|
I 12, II 22
|
I 13, II 24
|
40.1 (16.8)
|
41.3 (14.4)
|
18/16
|
24/13
|
3 [1.5–4.7]
|
3 [1–5]
|
PD 12
|
PD 9
|
|
Familiari, 2016 [26] (abstract)
|
RCT, Nov 2015 single center, Italy
|
35
|
38
|
I 8, II 27
|
I 10, II 28
|
46.8 (15.4)
|
45.9 (13.9)
|
19/16
|
20/18
|
4.3 (5.85)
|
3.49 (6.44)
|
Btx 2, PD 6
|
Btx 1, PD 2
|
SD, standard deviation; BD, balloon dilation; Btx, botulinum toxin injection; HM,
Heller myotomy; PD, pneumatic dilation.
Table 2
Procedure and outcome details.
|
Study
|
Operative time, mean (SD) [range], minutes
|
Myotomy length, E-Esophageal, G-Gastric, mean (SD) [range], cm
|
Outcomes
|
LOS, mean (SD) [range], days
|
Follow-up, mean (SD) [range], months
|
|
Clinical success
|
Postoperative GERD
|
Adverse events
|
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
Short
|
Standard
|
|
Li, 2019
|
39.5 [21–74]
|
49.2 [23–120]
|
4.8 [3–6] [Total],
E 2.9 [2–4], G 2.0 [1–3]
|
9.2 (8–11) [Total],
E 6.9 [5–9], G 2.3 [2–4]
|
56/63
|
55/63
|
6/63 (symptomatic)
|
8/63 (symptomatic)
|
6/63 [Total],
(PneumoP 2, PneumoM 0, Mucosal inj 4, Major bleeding 0)
|
21/63 [Total],
(PneumoP 3, PneumoM 1, Mucosal inj 5, Major bleeding 0)
|
NR
|
NR
|
20.1 [6–48]
|
23.6 [6–48]
|
|
Huang, 2020
|
46.6 (18.5) [20.0–100.0]
|
62.1 (25.2) [30.0–180]
|
6.0 (0.6) [5.0–7.0] [Total],
E 4.0 (0.7) [3–6], G 2.1 (0.3) [1–3]
|
11.5 (3.1) [8–25] [Total],
E 8.2 (2.7) [6–20], G 3.2 (1.2) [2–5]
|
34/36
|
68/74
|
3/36 (symptomatic); 1/36 (EGD)
|
11/74 (symptomatic); 6/74 (EGD)
|
3/36 [Total],
(Mucosal inj 0, PneumoT 1, Major bleeding 2)
|
6/74 [Total], (Mucosal inj 1, PneumoT 2, Major bleeding 3)
|
9.9 (2.4) [5–14]
|
9.3 (2.9) [5–15]
|
26.8 [8–54.3]
|
29.5 [6–58.8]
|
|
Gu, 2020
|
31.2 (15.3)
|
45.6 (16.2)
|
5.66 (0.14) [Total],
E [3–4], G [2–3]
|
10.14 (0.54) [Total],
E [7–8], G [2–3]
|
44/46
|
45/48
|
7/46 (symptomatic); 4/46 (EGD); 11/46 (pH)
|
11/48 (symptomatic); 7/48 (EGD); 21/48 (pH)
|
0/46 [Total],
(Mucosal inj 0)
|
1/48 [Total], (Mucosal inj 1)
|
7.0 (0.9)
|
6.5 (1.6)
|
12
|
12
|
|
Nabi, 2020
|
44.03 (13.78)
|
72.43 (27.28)
|
E 2.76 (0.41), G 2.70 (0.73)
|
E 7.97 (2.40), G 2.84 (0.63)
|
29/31
|
32/33
|
11/34 (EGD); 7/27 (pH)
|
18/37 (EGD); 12/20 (pH)
|
4/34 [Total],
(Mucosal inj 1, PneumoP 3)
|
4/37 [Total], (Mucosal inj 1, PneumoP 3)
|
2.82 (0.67)
|
2.81 (0.70)
|
12
|
12
|
|
Familiari, 2016 (abstract)
|
47.7 (13.2)[24–85]
|
59.2 (16.7) [30–106]
|
8 (0.6) [7–9] [Total],
E 5 [3–6], G3 [1–4]
|
13 (1) [11–15] [Total],
E 10 [7–11], G3 [2–5]
|
32/32
|
28/29
|
15/27 (symptomatic)
|
10/21 (symptomatic)
|
PneumoP 0, Mucosal perforation 0, Ulcers 5
|
PneumoP 1, Mucosal perforation 1, Ulcers 6
|
2.6 (0.9) [2–4]
|
2.3 (0.7) [2–4]
|
8.09 (3.05) [6–12]
|
8.3 (2.9) [6–12]
|
SD, standard deviation; GERD, gastroesophageal reflux disease; LOS, length of hospital
stay; PneumoP, pneumoperitoneum; PneumoM, pneumomediastinum; PneumoT, pneumothorax;
NR, not reported; EGD, esophagogastroduodenoscopy.
Meta-analysis outcomes
-
The pooled rate of clinical success was 95.1 % (95 %CI 91.4–98.7) in the short myotomy
group and 93.3 % (95 %CI 89.1–97.5) in the standard myotomy group. There was no statistically
significant difference between the two groups (OR 1.17, 95 %CI 0.54–2.52; I2
0 %; P = 0.69) ([Fig. 1]).
-
The pooled rate of symptomatic postoperative GERD was 22.6 % (95 %CI 5.6–39.6) in
the short myotomy group and 20.2 % (95 %CI 10.8–29.5) in the standard myotomy group. There
was no statistically significant difference between the two groups (OR 0.87, 95 %CI
0.44–1.74; I2
29 %; P = 0.70) ([Fig. 2]).
-
The pooled rate of postoperative erosive esophagitis as determined by endoscopy was
12.4 % (95 %CI 0–25.2) in the short myotomy group and 22.3 % (95 %CI 3.3–41.4) in
the standard myotomy group. The difference between the two groups was statistically
significant (OR 0.50, 95 %CI 0.24–1.03; I2
0 %; P = 0.06) ([Fig. 3]).
-
The pooled rate of overall adverse events was 6.5 % (95 %CI 0.6–12.4) in the short
myotomy group and 12.5 % (95 %CI 1.9–23.1) in the standard myotomy group. There was
no statistically significant difference between the two groups (OR 0.52, 95 %CI 0.19–1.38;
I2
40 %; P = 0.19) (Supplementary Fig. 3s).
-
The pooled rate of mucosal injury was 2 % (95 %CI 0–4) in the short myotomy group
and 2.4 % (95 %CI 0.3–4.4) in the standard myotomy group. There was no statistically
significant difference between the two groups (OR 0.74, 95 %CI 0.25–2.17; I2
0 %; P = 0.58) (Supplementary Fig. 4s).
-
The pooled mean LOS was 6.55 days (95 %CI 2.98–10.12) in the short myotomy group and
6.19 days (95 %CI 2.47–9.91) in the standard myotomy group. There was no statistically
significant difference between the two groups (OR 0.25, 95 %CI –0.14 to 0.63; I2
37 %; P = 0.21) (Supplementary Fig. 5s). All outcomes with I2
values are summarized in [Table 3].
Fig. 1 Forest plot, clinical success. M-H, Mantel-Haenszel; CI, confidence interval.
Fig. 2 Forest plot, postoperative symptomatic gastroesophageal reflux disease. M-H, Mantel-Haenszel;
CI, confidence interval.
Fig. 3 Forest plot, postoperative erosive esophagitis. M-H, Mantel-Haenszel; CI, confidence
interval.
Table 3
Summary of pooled results.
|
Outcome/group
|
Pooled proportion, % (95 %CI)
|
OR (95 %CI),
P value, I2
|
|
Short myotomy
|
Standard myotomy
|
|
Clinical success
|
95.1 (91.4–98.7)
|
93.3 (89.1–97.5)
|
1.17 (0.54–2.52),
P = 0.69, I2 0 %
|
|
Postoperative GERD (symptomatic)
|
22.6 (5.6–39.6)
|
20.2 (10.8–29.5)
|
0.87 (0.44–1.74),
P = 0.70, I2 29 %
|
|
Postoperative GERD (EGD)
|
12.4 (0–25.2)
|
22.3 (3.3–41.4)
|
0.50 (0.24–1.03),
P = 0.06, I2 0 %
|
|
Total adverse events
|
6.5 (0.6–12.4)
|
12.5 (1.9–23.1)
|
0.52 (0.19–1.38),
P = 0.19, I2 40 %
|
|
Mucosal injury
|
2 (0–4)
|
2.4 (0.3–4.4)
|
0.74 (0.25–2.17),
P = 0.58, I2 0 %
|
|
Length of stay
|
6.55 (2.98–10.12)
|
6.19 (2.47–9.91)
|
0.25 (–0.14–0.63),
P = 0.21, I2 37 %
|
CI, confidence interval; OR, odds ratio; GERD, gastroesophageal reflux disease; EGD,
esophagogastroduodenoscopy.
Validation of meta-analysis results
Sensitivity analysis
To assess whether any one study had a dominant effect on the meta-analysis, we excluded
one study at a time and analyzed its effect on the main summary estimate. We analyzed
the effect of excluding the study by Familiari et al., published as an abstract, on
clinical success. We found that exclusion of this study did not significantly affect
the primary outcome or influence the heterogeneity.
Heterogeneity
We assessed dispersion of the calculated rates using the I2 percentage values as reported
in the meta-analysis outcomes section. While the overall the heterogeneity was low,
there was evidence of moderate heterogeneity in our secondary end points (i. e. overall
adverse events and LOS).
Publication bias
Based on visual inspection of the funnel plot for clinical success and GERD outcomes,
there was no evidence of publication bias (Supplementary Fig. 6s).
Discussion
Our analysis shows that performing POEM with a shorter esophageal myotomy length in
patients with achalasia is noninferior to standard length myotomy. While the incidence
of postoperative symptomatic GERD was similar between the two groups, patients with
shorter myotomies were statistically less likely to have endoscopic evidence of erosive
esophagitis. The overall rates of adverse events, risk of mucosal injuries, and LOS
were similar between the two groups of patients.
Since the first reports over a decade ago [4], POEM has become a standard treatment for achalasia and related disorders worldwide
owing to its less invasive nature and higher curative effect than conventional therapeutic
methods [34]. Despite the clinical efficacy of POEM, post-procedure GERD remains one of the most
frequent complications encountered in clinical practice. Current evidence suggests
that symptomatic GERD occurs in 8.5 %–19 % of patients, while endoscopic findings
of erosive esophagitis are detected in 13 %–29.4 % of patients post-procedure [35]
[36]
[37]. Several procedural modifications have been made to POEM in an attempt to make the
procedure safer, more effective, and the results more highly reproducible. Some of
these modifications include a change in the myotomy approach (full thickness – when
all muscle layers are cut; partial thickness – when only the circular layer is cut),
location of the tunneling (anterior wall between 1 and 2 o’clock position; posterior
wall between 5 and 6 o’clock position), and length of myotomy (long ≥ 7 cm; or short
< 7 cm). While studies have shown that a gastric myotomy length of more than 2.5 cm
results in increased rates of moderate esophagitis without improving overall clinical
efficacy [15], the effect of altering esophageal myotomy length is not well established. Our study
is the first in the literature to assess the effect of esophageal myotomy length on
postoperative GERD and to analyze its effect on the clinical effectiveness of POEM.
Some of the commonly reported complications of POEM include mucosal perforations [38]
[39], pneumothorax [40], pneumoperitoneum [41]
[42], pneumomediastinum [43], and subcutaneous emphysema [39]
[40]
[43]. In our analysis, we found that while overall adverse events occurred in a greater
proportion of patients undergoing standard length myotomy compared with those undergoing
short myotomy, the difference between the two groups was not statistically significant.
It is important to note that the operative time across studies was significantly longer
when performing standard esophageal myotomy (45.6–72.43 vs. 31.2–47.7 minutes). We
found no statistical difference in the pooled rates of mucosal injury between the
two groups (2 % vs. 2.4 %; P = 0.58). Pneumoperitoneum was reported five patients, pneumothorax in one patient,
and major bleeding in two patients in the short myotomy group. Finally, we found no
difference in the overall LOS between the two groups.
There are several strengths to our review. First, we included only those studies where
outcomes of short myotomy length were compared with those of the standard technique,
including three RCTs [22]
[23]
[26]. This allowed us to perform a more robust meta-analysis of procedural outcomes.
Second, given the significant differences in the incidence of GERD as assessed by
symptomology, endoscopic evidence and pH monitoring [44], we calculated the pooled rates of symptomatic and erosive esophagitis separately.
Third, we conducted a systematic literature search with well-defined inclusion criteria,
careful exclusion of redundant studies, inclusion of good quality studies with detailed
extraction of data and rigorous evaluation of study quality. Finally, we excluded
all studies in which POEM was performed for non-achalasia indications such as jackhammer
esophagus and diffuse esophageal spasm because of the variable lengths of myotomy
in these conditions [45].
There are several limitations to this study, most of which are inherent to any meta-analysis.
First, one of the included studies in our analysis only reported interim outcomes
at 6 months [26], two studies reported outcomes at 12 months [22]
[23], and two studies reported outcomes beyond 20 months [24]
[25]. The mean follow-up period varied across studies, ranging from 8.09 months to 29.5
months. While the overwhelming majority of patients (n = 364) included in our analysis
had Type II achalasia, four patients had Type III achalasia. Although not standardized,
a longer myotomy is thought to be more effective at controlling symptoms caused by
the esophageal spasm of type III achalasia [7]
[45]
[46]. One of the included studies was published only in abstract format [26]. We contacted the authors via email to obtain details about patient characteristics
and procedure outcomes, as reported in our study. However, we were informed that the
trial is ongoing at this time. We were unable to compare short and long esophageal
myotomy groups in terms of objective pH-based outcomes of GERD (i. e. 24-hour pH-impendence
results), as this information was provided in only two trials [22]
[23]. Two of the studies included in our analysis were retrospective in design, and while
they were both of high quality, their inclusion could have resulted in selection bias.
The absence of blinding of outcome assessment by Gu et al. could have resulted in
detection bias. Finally, we were unable to assess risk of bias in the study by Familiari
et al., as it was only published as an abstract.
In conclusion, our study showed that performing POEM with short esophageal myotomy
length appeared to be as clinically effective as standard myotomy. Both approaches
had similar safety profiles. While incidence of symptomatic GERD was comparable between
the two techniques, erosive esophagitis tended to occur less frequently with the short
myotomy approach. It is important to note that statistical nonsignificance may not
be an indication of equivalence but rather of uncertainty. Further RCTs with longer
follow-up times are needed to validate our results.
