Findings of Esophagography for 25 Patients After Peroral Endoscopic Myotomy for Achalasia

Transcription

1 Gastrointestinal Imaging Original Research Levy et al. Esophagography Findings fter POEM for chalasia Gastrointestinal Imaging Original Research Jennifer L. Levy 1 Marc S. Levine 1 Stephen E. Rubesin 1 Gary W. Falk 2 David C. Metz 2 Daniel T. Dempsey 3 Gregory G. Ginsberg 2 Levy JL, Levine MS, Rubesin SE, et al. Keywords: achalasia, barium esophagography, esophagography, peroral endoscopic myotomy (POEM), radiographic findings DOI: /JR Received February 29, 2016; accepted after revision May 16, M. S. Levine and S. E. Rubesin are consultants for racco Diagnostics, Inc. 1 Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, P ddress correspondence to M. S. Levine (marc.levine@uphs.upenn.edu). 2 Division of Gastroenterology, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, P. 3 Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, P. This article is available for credit. JR 2016; 207: X/16/ merican Roentgen Ray Society Findings of Esophagography for 25 Patients fter Peroral Endoscopic Myotomy for chalasia OJECTIVE. The purpose of this study is to better characterize the findings of esophagography after peroral endoscopic myotomy for achalasia. MTERILS ND METHODS. We evaluated 25 patients who underwent peroral endoscopic myotomy for achalasia. The findings noted on pre- and postprocedural esophagrams were reviewed retrospectively and were correlated with clinical outcomes. RESULTS. None of the patients had esophageal perforation noted on esophagrams obtained after myotomy, and all but two patients had a hospital stay that lasted 1 day only. Esophagrams obtained on postoperative day 1 revealed endoscopic clips in 25 patients (100%), pneumoperitoneum in 18 (72%), retroperitoneal gas in 10 (40%), gastric pneumatosis in nine (36%), intramural dissections in seven (28%), and pneumomediastinum in four (16%). Repeat esophagrams obtained 3 weeks later for 22 of the patients revealed endoscopic clips in 16 patients (73%) and intramural dissections in five patients (23%), but the remaining findings had resolved. Eighteen patients (72%) had a successful myotomy and seven (28%) had suboptimal results on the basis of clinical outcomes. Observation of a distal esophageal width of 5 mm or less on postprocedural esophagrams was often associated with suboptimal results. CONCLUSION. Peroral endoscopic myotomy is a novel procedure that is less invasive than is laparoscopic Heller myotomy for the treatment of achalasia, with fewer complications and shorter recovery times. Radiologists should be aware of the findings expected on esophagography (including pneumoperitoneum, retroperitoneal gas, gastric pneumatosis, intramural dissections, and pneumomediastinum) and should also know that fluoroscopic studies may be helpful for predicting patient outcomes on the basis of the width of the distal esophagus after myotomy. chalasia is an esophageal motility disorder characterized by a combination of absent peristalsis in the esophagus and incomplete opening of the lower esophageal sphincter (LES). Common symptoms of achalasia include dysphagia and regurgitation of food retained in the esophagus. Primary (i.e., idiopathic) achalasia must be differentiated from secondary achalasia due to other causes, such as malignant tumor at the gastroesophageal junction [1]. Primary achalasia (hereafter referred to simply as achalasia ) is thought to be an autoimmune disorder triggered by latent viral infection and neuronal degeneration of myenteric plexus ganglia in the esophagus [2]. chalasia is usually treated by alleviating obstruction at the gastroesophageal junction secondary to LES dysfunction. Shortterm control of symptoms can be achieved by means of injection of botulinum toxin into the LES, whereas long-term treatment entails performing either pneumatic dilation of the LES or a laparoscopic procedure known as Heller myotomy [3]. With Heller myotomy, both the circular and longitudinal muscles of the distal esophagus and proximal stomach are incised to disrupt the LES and facilitate esophageal emptying (often in combination with a partial fundoplication to prevent reflux) [4]. In a study of long-term outcomes, pneumatic dilation and Heller myotomy were shown to be equally effective, providing that dilations were repeated when symptoms recurred [5]. Peroral endoscopic myotomy (POEM) is a novel less-invasive approach for the long-term treatment of achalasia that was first described in 2010 [6]. POEM is an endoscopic procedure in which the mucosa in the midesophagus is incised and a submucosal tunnel is created to access and transect the circular muscle of the LES from its luminal side [7]. Studies have shown that POEM and Heller myotomy JR:207, December

2 Levy et al. Fig year-old man with achalasia. Closeup view from upright frontal scout image from esophagram obtained 1 day after patient underwent peroral endoscopic myotomy shows six endoscopic clips (large arrow) clustered together at site of closure of mucosal incision in esophagus and one clip (small arrow) that migrated into stomach. Pneumoperitoneum (arrowhead) is also shown beneath right hemidiaphragm. produce comparable results for treating achalasia in terms of symptomatic relief and improved opening of the LES [8 13]. POEM also has been associated with fewer esophageal perforations or other postoperative complications [4, 14 17] and with shorter hospital stays [18, 19] than has Heller myotomy. Many centers routinely perform water-soluble contrast esophagrams 1 day after POEM, to evaluate for leaks or other complications [14]. Reported radiographic findings include pneumoperitoneum, pneumomediastinum, gastric pneumatosis, intramural dissections, and retained endoscopic clips [20]. ecause POEM is a relatively new technique, however, little is known about the frequency and clinical importance of these findings. The purpose of the present study is to better characterize the findings noted on esophagography after POEM is performed for achalasia. Materials and Methods Institutional Review oard pproval The institutional review board at the Hospital of the University of Pennsylvania approved all aspects of the present retrospective study and did not require informed consent from patients included in the study. The investigation was also HIP compliant. Patient Population retrospective review of computerized records at the Hospital of the University of Pennsylvania identified 26 consecutive patients who underwent POEM for achalasia during the 1.5-year period from pril 2014 to October One patient was excluded because his achalasia was diagnosed after Roux-en-Y gastric bypass, so he could have developed secondary achalasia. For the remaining 25 patients, the manometric, radiographic, and clinical findings were compatible with achalasia. These 25 patients constituted our study group. Fourteen patients (56%) were men, and 11 (44%) were women. The patients had a mean age of 53 years (range, years). Peroral Endoscopic Myotomy ll POEMs were performed by an experienced gastroenterologist, using the technique developed by Inoue et al. [6] in The procedure was performed with general anesthesia and endotracheal intubation, using a high-definition endoscope and insufflation of carbon dioxide. n entry site in the esophagus was selected approximately 12 cm proximal to the squamocolumnar junction. fter methylene blue tinted normal saline was injected into the submucosa to separate the mucosa from the muscle layer, a triangle-tip knife was used to create a 2-cm-long mucosal incision in the esophageal wall. Submucosal fibers were then lysed to create a submucosal tunnel extending distally from the entry side to and below the LES and approximately 2 3 cm into the proximal stomach. myotomy was performed using the triangle-tip knife via this submucosal tunnel, thereby dissecting and disrupting the inner circular muscle fibers of the distal esophagus, LES, and gastric cardia. The endoscope was then removed from the submucosal tunnel and was advanced through the esophagus across the gastroesophageal junction and into the proximal stomach to ensure adequate luminal patency. Finally, the entry site in the esophagus was closed with the use of standard endoscopic clipping techniques. The patient underwent extubation immediately after the procedure and was not allowed to receive anything by mouth for 24 hours while receiving empirical treatment with an IV proton pump inhibitor. Water-soluble contrast esophagrams were performed the next morning, and if no leak was detected, the patient was allowed to have a clear liquid diet and was discharged from the hospital on postoperative day 1. full liquid diet was provided on postoperative day 2, a soft diet on postoperative day 3, and a regular diet on postoperative day 5. nalgesic medication was also provided, as needed. Esophagography ll 25 patients had an esophagram obtained 1 day after POEM (hereafter referred to as the first post-poem esophagram ), and 22 patients had a repeat esophagram obtained approximately 3 weeks later (hereafter referred to as the second post-poem esophagram ) (mean interval, 22 days; range, days). Twenty-four patients (96%) had a preoperative esophagram (hereafter referred to as a pre-poem esophagram ) (mean interval between esophagram and POEM, 187 days; range, days) available for review in the PCS in the radiology department at our institution. Residents, fellows, or attending gastrointestinal radiologists obtained all of the post-poem esophagrams with the use of digital fluoroscopic equipment. On postoperative day 1, a study was initially performed using a water-soluble contrast agent (Gastrografin, racco Diagnostics), with the patient in an upright or semiupright position. If no leak was detected, the study was immediately repeated using a 250% (weight/ volume) barium suspension (EZ-HD, racco Diagnostics). In contrast, a repeat esophagram was obtained with the use of the same 250% (weight/ volume) barium suspension 3 weeks later, with the patient in the upright position, and was followed with the use of a 40% (weight/volume) barium suspension (diluted liquid Polibar Plus, racco Diagnostics), with the patient in the prone right anterior oblique position. ll of the pre-poem and post-poem esophagrams were interpreted by the consensus of two experienced gastrointestinal radiologists who had Fig year-old man with achalasia. Closeup view from upright frontal scout image from esophagram obtained 1 day after patient underwent peroral endoscopic myotomy shows cluster of endoscopic clips (arrowhead) at site of closure of mucosa incision in esophagus. (Clips are superimposed in this projection.) Extensive retroperitoneal gas (arrows) is also shown in medial aspect of right upper abdomen. This patient recovered uneventfully JR:207, December 2016

3 Esophagography Findings fter POEM for chalasia TLE 1: Eckardt Scoring System for chalasia Symptom no knowledge of the postoperative clinical findings or clinical course. The esophagrams were reviewed for the presence or absence of a postprocedural leak from the esophagus or gastroesophageal junction. Our impressions about a leak were later compared with the findings in the original radiology reports, and no discrepancies were found. Measurements of both the width of the narrowest segment of the distal esophagus in the region of the LES and the maximal esophageal diameter above the LES were obtained, with a barium tablet with a 12-mm diameter used as the reference standard. Delayed emptying of the esophagus was defined by the presence of a standing column of contrast material or barium in the esophagus at the end of the examination. Data on the presence or absence of primary peristalsis, nonperistaltic contractions, retention of food or fluid in the esophagus, a hiatal hernia, and gastroesophageal reflux were also recorded after both the esophagrams and the original radiology reports were reviewed. The contour (smooth versus irregular) and symmetry (symmetric versus asymmetric) of the narrowed distal esophageal segment were also recorded. Finally, the esophagrams were reviewed to determine the presence or absence of other radiographic findings after POEM, including intramural dissections, pneumoperitoneum, pneumomediastinum, retroperitoneal gas, esophageal pneumatosis, gastric pneumatosis (as characterized by the presence of linear or mottled gas in the wall of the proximal stomach), and endoscopic clips [20]. ccording to the classification system developed by Pechlivanides et al. [21], the esophageal caliber was considered to be normal if the diameter was 4 cm or less, mildly dilated if the diameter was cm, and markedly dilated if the diameter was greater than 6 cm or if the distal esophagus had a sigmoid configuration. Score Dysphagia None Occasional Daily With every meal Regurgitation None Occasional Daily With every meal Substernal pain None Occasional Daily With every meal Weight loss (kg) 0 < > 10 Note The total Eckardt score for a given patient is the sum of the four component scores. Variables and Outcomes The electronic medical records of all 25 patients were reviewed to collect data on diagnostic studies (manometry and endoscopy) performed before POEM, previous treatment of achalasia, post-poem complications, and the clinical course of the patient. On the basis of the Chicago classification system for manometric determination of achalasia subtypes [22], two patients (8%) had type I achalasia, 20 (80%) had type II achalasia, and three (12%) had type III achalasia. Medical records were available for a review of the pre-poem clinical symptoms of all 25 patients, for review of the symptoms noted at the first postoperative office visit (i.e., short-term clinical follow-up; mean interval after POEM, 22 days; range, days) for 24 patients, and for review of the symptoms noted at the second postoperative visit (i.e., long-term clinical follow-up; mean interval after POEM, 156 days; range, days) for six patients. s in previous studies [18, 23, 24], the clinical status of the patient before and after POEM was determined by calculation of Eckardt symptom scores on the basis of the presence and frequency of dysphagia, regurgitation, retrosternal pain, and weight loss [25], with use of the scoring system summarized in Table 1. Fifteen patients (60%) underwent upper endoscopy approximately 7 months after undergoing POEM (mean interval after POEM, 231 days; range, days). The findings on the endoscopic reports (including dilation and tortuosity of the esophagus, retention of food or fluid in the esophagus, reflux esophagitis, and the presence of stenosis of the LES) were recorded. Data on additional post-poem interventional procedures, such as endoscopic through-the-scope balloon dilation (up to 20 mm) or repeat POEM, were also recorded. s noted in a previous study [24], a suboptimal result was defined by the assignment of an Eckardt score of greater than 3 at the most recent postoperative office visit or by the need for other therapeutic procedures. The mean length of clinical follow-up in the present study was 144 days (range, days). Statistical nalysis Continuous variables evaluated before and after POEM were compared using a paired t test. In contrast, a Fisher exact test was used to compare categoric variables for patients for whom treatment failed versus those for whom treatment did not fail. p < 0.05 was used as the threshold denoting statistical significance. ll statistical tests were performed using Excel (version 2011, Microsoft) or a free calculator available online (Graph- Pad QuickCalcs, GraphPad Software). Results Clinical Findings Data on preoperative symptoms and previous treatments received are presented in Table 2. ll 25 patients presented with dysphagia, regurgitation, and substernal chest pain, and 18 had associated weight loss. The patients had a mean preoperative Eckardt score of 8.8 (range, 5 12). Twenty-three of the 25 patients who underwent POEM (92%) had no complications resulting from the procedure. One patient (4%) aspirated residual food in the esophagus during induction of anesthesia, necessitating a 2-week postponement of the procedure. The remaining patient (4%) had upper gastrointestinal bleeding from a mucosal laceration in the distal esophagus that resolved with conservative management. For 23 patients (92%), the hospital stay lasted 1 day, and for the remaining two patients (8%), the hospital stay lasted 3 days. TLE 2: Clinical Findings and Previous Treatment for 25 Patients With chalasia Finding or Symptom Value Dysphagia 25 (100) Solids and liquids 17 (68) Solids only 3 (12) Liquids only 0 (0) Not recorded 5 (20) Substernal pain 25 (100) Regurgitation 25 (100) Weight loss 18 (72) Chronic cough 13 (52) Postprandial vomiting 6 (24) spiration 4 (16) Postprandial nausea 1 (4) Eckardt symptom score, mean 8.8 (5 12) (range) Previous treatment 14 (56) otulinum toxin injections only 6 (24) Pneumatic dilation only 6 (24) otulinum injections and pneumatic 2 (8) dilation Note Except where indicated otherwise, data are no. (%) of patients. JR:207, December

4 Levy et al. Fig year-old man with achalasia., Close-up view from upright scout image from esophagram obtained 1 day after patient underwent peroral endoscopic myotomy shows pneumoperitoneum (white arrow) beneath medial aspect of right hemidiaphragm. Gas (black arrow) is shown in wall of proximal stomach. One endoscopic clip (arrowhead) has migrated into stomach., Frontal spot image from esophagram confirms presence of gas (arrows) in medial wall of opacified proximal stomach (i.e., gastric pneumatosis). This patient recovered uneventfully. Eighteen of 24 patients with short-term clinical follow-up (75%) had decreased dysphagia, regurgitation, or substernal chest pain or decreases in a combination of these findings; five patients (21%) were asymptomatic; and one patient (4%) had continued symptoms without improvement. The mean Eckardt score at short-term follow-up was 1.7 (range, 0 5), with an improvement of 7.1 points noted in comparison with the mean preoperative Eckardt score (p < 0.01). When an Eckardt score of less than 4 was used as the threshold for a successful clinical outcome [12, 18], 21 patients (88%) had adequate symptom relief after POEM at short-term clinical follow-up, and three (13%) did not. Four of six patients with long-term clinical follow-up (67%) had decreased dysphagia, regurgitation, or substernal chest pain, or decreases in a combination of these findings; one patient (17%) was asymptomatic, and one patient (17%) had symptoms continue without improvement. The mean Eckardt score at long-term clinical follow-up was 2.2 (range, 0 7), with an improvement of 6.6 points noted in comparison with the mean preoperative Eckardt score (p < 0.01). Five patients (83%) had adequate symptom relief after POEM at long-term follow-up, and one (17%) did not. Six of 15 patients (40%) who underwent endoscopy after POEM had retained food, fluid, or both in the esophagus; five (33%) had a dilated esophagus; and three (20%) had distal esophageal narrowing secondary to continued LES dysfunction. No patient had evidence of reflux esophagitis at the time that endoscopy was performed. Six of 25 patients (24%) underwent additional therapeutic procedures because of continuing dysphagia and regurgitation. ll six of these patients underwent endoscopic dilation (mean interval after POEM, 107 days; range, days), and one also underwent repeat POEM 4.5 months later. One patient who did not undergo an additional intervention had an Eckardt score greater than 3 during the most recent postoperative office visit. Thus, seven of the 25 patients (28%) had suboptimal clinical results. The remaining 18 patients (72%) had a successful clinical outcome. Radiographic Findings The radiographic findings on the pre-poem esophagrams, the first post-poem esopha- Fig year-old woman with achalasia., Right posterior oblique spot image from esophagram obtained 1 day after patient underwent peroral endoscopic myotomy shows intramural dissection (arrows) as thin linear collection in esophageal wall separated from lumen by radiolucent stripe of overlying mucosa. Proximal end of dissection communicates with lumen. Transversely oriented endoscopic clips are shown projecting from lumen in region of dissection. This patient had no symptoms related to dissection., Right posterior oblique spot image from repeat esophagram performed 3 weeks after esophagram shown in shows complete resolution of intramural dissection seen on earlier esophagram. Endoscopic clips have all passed from esophagus JR:207, December 2016

5 Esophagography Findings fter POEM for chalasia grams, and the second post-poem esophagrams are summarized in Table 3. No patients were found to have perforation of the esophagus or proximal stomach on the first or second post-poem esophagram. Scout images revealed a variable number of radiopaque endoscopic clips clustered together at the site of the incision in the midesophagus in all 25 patients (100%) on the first post-poem esophagram (mean number of clips, 9.4; range, 5 19 clips) (Figs. 1 and 2) and in 16 of the 22 patients (73%) for whom second post-poem esophagrams were obtained (mean number of clips, 3.3; range, 1 7 clips). In two of the 25 patients (8%), one of the clips was noted to have migrated into the stomach on the first post-poem esophagram (Figs. 1 and 3), and in two of 22 patients (9%), clips (five clips in one patient and one clip in the second patient) were observed to have migrated into the colon on the second post-poem esophagram. The first post-poem esophagrams revealed intramural dissection of contrast material into the submucosal tunnel at a variable distance distally from the site of the mucosal incision in seven of 25 patients (28%) (Figs. 4 and 5). In all seven patients, the lumen communicated with the proximal end of the dissection at the site of the incision. These dissections had a mean length of 2.8 cm (range, cm) and a mean width of 3.4 mm (range, 2 7 mm). The second post-poem esophagrams revealed intramural dissections in five of 22 patients (23%), including three patients in whom the dissection was detected on the first post- POEM esophagram (Fig. 5) and two patients in whom the dissection was detected on the second post-poem esophagram only. Thus, the intramural dissections were noted to have resolved on the second post-poem esophagrams in four of seven patients (57%) who had dissections observed on the first post-poem esophagrams (Fig. 4). The first post-poem esophagrams revealed pneumoperitoneum (i.e., free air beneath one or both diaphragms) in 18 patients (72%) (Figs. 1 and 3), retroperitoneal gas in 10 patients (40%) (Fig. 2), gastric pneumatosis in nine patients (36%) (Fig. 3), and pneumomediastinum in four patients (16%) as normal findings without associated symptoms, but no patients had esophageal pneumatosis. In contrast, the second post-poem esophagrams revealed none of these findings, because the findings had all resolved in the interim. The narrowed distal esophagus had a mean width of 3.4 mm (range, 1 8 mm) on pre-poem esophagrams versus a mean width TLE 3: Radiographic Findings on Esophagrams Obtained efore Peroral Endoscopic Myotomy (POEM) and First and Second Esophagrams Obtained fter POEM Finding Pre-POEM Esophagrams (n = 24) of 6.6 mm (range, 2 16 mm) on the first post- POEM esophagrams and a mean width of 6.0 mm (range, 2 14 mm) on the second post- POEM esophagrams. Thus, the narrowed distal esophagus had a mean increase in width of 3.2 mm from the time that the pre-poem esophagrams were obtained to the time when the first post-poem esophagrams were obtained (p < 0.01) and a mean increase in width of 2.6 mm from the time that the pre-poem esophagrams were acquired to the time when the second post-poem esophagrams were First Post-POEM Esophagrams (n = 25) Second Post-POEM Esophagrams (n = 22) Smooth tapered distal lumen 24 (100) 24 (96) 22 (100) Distal esophagus shape Symmetric 22 (92) 23 (92) 19 (86) symmetric 2 (8) 2 (8) 3 (14) Mean width of narrow segment a 6.0 b (mm) Mean length of narrow segment c 8.9 d (mm) Sigmoid esophagus 4 (17) 3 (12) 1 (5) Mean maximum esophageal e 3.1 f diameter (cm) Esophageal caliber g Normal 16 (67) 19 (76) 18 (82) Mildly dilated 3 (13) 3 (12) 3 (14) Markedly dilated 5 (21) 3 (12) 1 (5) Delayed emptying 23 (96) 25 (100) 20 (91) Primary peristalsis bsent 21 (88) 20 (80) 15 (68) Intermittent 2 (8) 2 (8) 4 (18) Decreased amplitude 1 (4) 0 (0) 0 (0) Not recorded 0 (0) 3 (12) 3 (14) Nonperistaltic contractions 9 (38) 9 (36) 15 (69) Food, fluid, or both 13 (54) 0 (0) 3 (14) Gastroesophageal reflux 0 (0) 1 (4) 1 (5) Hiatal hernia 17 (71) Note Except where indicated otherwise, data are the no. (%) of patients. First post-poem esophagrams were obtained at 1 day after POEM, whereas second post-poem esophagrams were obtained at approximately 3 weeks after POEM. The p values reflect differences between mean values on esophagrams obtained before and after POEM. Dash ( ) indicates data unavailable. a p < b p < c p = d p = e p = f p = g Esophageal caliber was defined on the basis of maximum width, as follows: normal, less than or equal to 4.0 cm; mildly dilated, cm; or markedly dilated, greater than 6.0 cm. obtained (p < 0.01), so there was a statistically significant increase in the width of the distal esophagus after POEM. The esophagus was not dilated in 16 patients (67%), was mildly dilated in three patients (13%), and was markedly dilated in five patients (21%) on pre-poem esophagrams. On the first post-poem esophagrams, the esophagus was not dilated in 19 patients (76%), was mildly dilated in three patients (12%), and was markedly dilated in three patients (12%), and on the second post-poem JR:207, December

6 Levy et al. esophagrams, the esophagus was not dilated in 18 patients (82%), was mildly dilated in three patients (14%), and was markedly dilated in one patient (5%). The most dilated segment of the esophagus had a mean width of 3.6 cm (range, cm) on pre-poem esophagrams versus a mean width of 3.2 cm (range, cm) on the first post-poem esophagrams (p = 0.42) and a mean width of 3.1 cm (range, cm) on the second post-poem esophagrams (p = 0.31). Thus, there was no statistically significant change in the caliber of the esophagus after POEM. Esophageal emptying was delayed in 23 of 24 patients, as noted on pre-poem esophagrams, and it was delayed in all 25 patients (100%) on the first post-poem esophagrams and in 20 of 22 patients (91%) on the second post-poem esophagrams. Correlation etween Radiographic Findings and Patient Outcomes Five of 10 patients (50%) for whom the mean width of the narrowed distal esophagus was 5 mm or less on the first post-poem esophagram had a suboptimal clinical response to POEM, compared with two of 15 patients (13%) for whom the mean distal width was greater than 5 mm (Figs. 6, 6, and 7). Similarly, six of 11 patients (55%) for whom the mean width of the narrowed distal esophagus was 5 mm or less on the second post- Fig year-old woman with achalasia., Right posterior oblique spot image from esophagram obtained 1 day after patient underwent peroral endoscopic myotomy shows intramural dissection (arrow) communicating with lumen of esophagus proximally. This patient had no symptoms related to dissection., Right posterior oblique spot image from repeat esophagram obtained 3 weeks after esophagram in shows continued evidence of intramural dissection (arrows) in midesophagus. Patient still had no symptoms related to dissection. POEM esophagrams had a suboptimal clinical response to POEM, compared with one of 11 patients (9%) for whom the mean distal width was greater than 5 mm (Fig. 6C). Thus, a mean distal width of 5 mm or less on the first (p = 0.075) or second (p = 0.064) post-poem esophagrams was more likely to be associated with a suboptimal clinical response to POEM. This association approached but did not reach statistical significance. Five of 19 patients (26%) with a normalcaliber esophagus on the first post-poem esophagrams had a suboptimal clinical response to POEM versus two of six patients (33%) with a dilated esophagus. Similarly, five of 18 patients (28%) who had a normalcaliber esophagus on the second post-poem esophagram had a suboptimal clinical response to POEM versus two of four patients (50%) who had a dilated esophagus. Thus, there was no association between the esophageal caliber noted on the first (p = 1.0) or second (p = 0.56) post-poem esophagrams and the clinical response to treatment. Discussion lthough pneumatic dilation and Heller myotomy have been shown to have comparable long-term efficacy in the treatment of achalasia [5], there is a growing body of evidence supporting the role of POEM in these patients. POEM has been shown to produce results comparable to those of Heller myotomy in terms of symptomatic relief and improved opening of the LES [8 13], with fewer esophageal perforations or other postoperative complications [4, 14 17] and shorter recovery times [18, 19]. In a study by hayani et al. [8], none of the 27 patients who underwent POEM had solid food dysphagia 6 months after undergoing the procedure, compared with 11 of 38 patients (29%) who underwent Heller myotomy. In a study by Inoue et al. [10], symptoms of achalasia were relieved in 260 of 286 patients (91%) 1 2 years after POEM, whereas symptom relief has been reported in 86 93% of patients at 1 year after Heller myotomy [12, 13]. POEM therefore has increasingly been advocated as a less invasive alternative to Heller myotomy for the control of symptoms in patients with achalasia [10, 18]. s POEM becomes more popular, radiologists are likely to encounter a greater number of patients who undergo this procedure. In one survey, 14 of 16 groups of investigators who performed POEMs (88%) routinely obtained an esophagram within 24 hours of the procedure to rule out perforation [14]. Radiologists therefore need to be aware of the various findings on esophagrams after POEM and also of the clinical importance of these findings. In the present study, no patients who underwent POEM had evidence of perforation on esophagrams obtained 1 day after the procedure was performed. Our findings are similar to the overall post-poem perforation rate of only 0.2% reported in the literature [14]. In contrast, the perforation rate after laparoscopic Heller myotomy has ranged from 0.9% to 5% [15 17]. Patients in the present study and those in an earlier study [18] had a mean hospital stay of only 1 day after POEM versus a mean hospital stay of 2.8 days after laparoscopic Heller myotomy [19]. Thus, POEM is associated with a lower perforation rate and a shorter recovery time than is laparoscopic Heller myotomy. Nevertheless, there is only one descriptive review of the findings on esophagography after POEM in the radiology literature [20]. In the present study, scout images from esophagrams obtained 1 day after POEM revealed endoscopic clips clustered together at the site of the incision in the midesophagus in all patients (Figs. 1 and 2); therefore, the presence of endoscopic clips in the chest should be recognized as a normal postoperative finding [20]. Nearly 75% of our patients 1190 JR:207, December 2016

7 Esophagography Findings fter POEM for chalasia C Fig year-old man with achalasia., Frontal spot image from preoperative esophagram shows tapered narrowing (arrow) of distal esophagus secondary to incomplete opening of lower esophageal sphincter. Diameter of narrowed segment was only 2 mm. Peristalsis was absent in esophagus. Patient had dysphagia, regurgitation, and substernal pain (Eckardt score, 5)., Frontal spot image from esophagram obtained 1 day after patient underwent peroral endoscopic myotomy (POEM) again shows marked narrowing (black arrow) of distal esophagus (diameter of which remained only 2 mm) without change from preoperative study shown in. Endoscopic clips (white arrows) are shown more proximally in wall of esophagus. ecause of degree of narrowing and delayed emptying of esophagus, this patient underwent pneumatic dilation of lower esophageal sphincter 1 day after image was obtained. C, Frontal spot image from repeat esophagram acquired 3 weeks after image in again shows marked narrowing (arrow) of distal esophagus (diameter of which remained only 2 mm), delayed emptying of esophagus, and greater esophageal dilatation more proximally. This patient had continued dysphagia and regurgitation (Eckardt score, 7), so repeat POEM was performed 140 days after first procedure. also had clips noted on esophagrams obtained 3 weeks after POEM, so clips may be retained in the esophagus for several weeks or longer. In one study by Teitelbaum et al. [18], retained clips were seen at repeat endoscopy performed 1 year after POEM in 45% of patients who had no clinical complications. In the present study, however, the mean number of clips decreased from 9.4 on the first post-poem esophagrams to 3.3 on the second post-poem esophagrams, so most of these clips were sloughed into the lumen and were passed from the bowel in a relatively short period. s with our patients, follow-up esophagrams occasionally may show that one or more clips have migrated into the stomach or intestines (Figs. 1 and 3). Nearly 30% of our patients had early post- POEM esophagrams that showed intramural dissections extending distally from the site of the endoscopic clips in the midesophagus, presumably because of persistent mucosal rents through an incompletely closed mucosectomy. On post-poem esophagrams, this finding was characterized by thin linear collections of contrast material in the esophageal wall parallel to and separated from the lumen by a radiolucent stripe representing the intact overlying mucosa (Figs. 4 and 5) [20]. The dissections caused no symptoms and, in most patients, were shown to have completely healed on repeat esophagrams obtained 3 weeks later (although two patients had intramural dissections detected on the second post-poem esophagram only, so it is unclear whether they were missed on the earlier studies or whether they developed in the interim). Our experience suggests that intramural dissections are a relatively common and clinically unimportant finding on early post-poem esophagrams and that they do not require any treatment. Pneumomediastinum, pneumoperitoneum, and retroperitoneal gas have been previously noted on esophagrams and CT scans obtained after POEM in the absence of esophageal or gastric perforation [20, 26, 27], presumably because of administered carbon dioxide escaping through rents in the esophageal wall into the mediastinum, peritoneal cavity, and retroperitoneum [28]. In the present study, pneumoperitoneum was detected in 72% (Figs. 1 and 3), retroperitoneal air in 40% (Fig. 2), and pneumomediastinum in 16% of the patients who had early post-poem esophagrams; however, these findings caused no clinical symptoms and had resolved on repeat esophagrams obtained 3 weeks later in all patients. Gastric pneumatosis, another finding that is known to be associated with a gamut of conditions ranging from benign to life-threatening [29], has also been reported after POEM [20] and was detected in 36% of our patients (Fig. 3); however, this finding also caused no clinical problems and resolved in all patients on follow-up esophagrams. These abnormalities should therefore be regarded as expected findings on early post-poem esophagrams, that almost always resolve on later esophagrams and have no clinical importance. Several studies have shown that early postoperative esophagrams have little value for predicting the success or failure of laparoscopic Heller myotomy [15, 30]. This observation is most likely related to the nature of the surgery, in which both the outer longitudinal and inner circular muscle fibers of the lower esophagus and gastric cardia are transected [4]. This deep incision causes substantial edema and spasm that narrow the distal esophagus in the region of the LES and impede emptying of contrast material into the stomach, preventing adequate assessment of the myotomy and its effect on the caliber of the distal esophagus during the early postoperative period. Our findings suggests that, unlike postoperative esophagrams obtained after Heller myotomy, early post-poem esophagrams may be helpful for predicting patient outcomes on the basis of the width of the distal esophagus. In the present study, a distal esophageal width of 5 mm or less on the first (p = 0.075) or second (p = 0.064) post-poem esophagrams was associated with a suboptimal treatment response (Fig. 6), in comparison with an esophageal width greater than 5 mm (Fig. 7). This finding approached but did not reach statistical significance, possibly because of the small number of patients in the present study. The caliber of the distal esophagus on esophagography could have greater predictive value after POEM than after Heller myotomy because POEM entails incising only the inner circular muscle layer of the esophagus, leaving the outer longitudinal layer intact [6]. s a result, there may be less transmural injury of the esophagus with less edema and spasm [8]. Whatever the explanation, our preliminary experience suggests that a distal esophageal width of 5 mm or less may be a useful parameter for helping to predict the likelihood of treatment fail- JR:207, December

8 Levy et al. ures after POEM, although additional studies with larger numbers of patients are needed to further elucidate the usefulness of this finding for assessing patient outcomes. Conversely, delayed emptying of contrast material from the esophagus was not a useful parameter for predicting the clinical response to treatment on post-poem esophagrams in the present study, because nearly all patients had some degree of delayed emptying after this procedure. Similarly, the degree of esophageal dilation noted on esophagrams obtained after POEM was not helpful for predicting patient outcomes. This is not surprising because it previously has been shown that symptoms of achalasia are primarily related to the degree of distensibility of the distal esophagus in the region of the LES rather than the degree of upstream dilation [31]. The present study has several limitations. Failure of POEM was defined by the presence of continued symptoms or the need for additional therapeutic interventions, but patients with achalasia may have an abnormal afferent vagal response, so patient symptoms are not always reliable for predicting outcomes [32, 33]. more objective measurement of treatment response, such as manometry or endoluminal functional imaging, may therefore be a better indicator of patient outcomes. The present study is also limited by the small size of the patient population, which may have prevented demonstration of a significant association between the caliber of the distal esophagus and patient outcomes. Fig year-old woman with achalasia., Right anterior oblique spot image from preoperative esophagram obtained with patient in prone position shows tapered narrowing (arrow) of distal esophagus secondary to incomplete opening of lower esophageal sphincter. Diameter of narrowed segment was 3 mm. Peristalsis was absent in esophagus with multiple nonperistaltic contractions noted. This patient had dysphagia, regurgitation, and substernal pain (Eckardt score, 5)., Right anterior oblique spot image from esophagram obtained with patient in prone position 1 day after peroral endoscopic myotomy was performed shows considerably improved opening of distal esophagus (arrow), diameter of which was now approximately 1 cm. Patient was asymptomatic 1 month later and had Eckardt score of 1. The study also had limited clinical followup, because the majority of patients had clinic visit 3 weeks after POEM and had endoscopy 7 months later without a second clinic visit. Similarly, there was a relatively short radiographic follow-up period, because the second post-poem esophagram was usually performed 3 weeks after the procedure; therefore, it was not possible to monitor the radiographic findings beyond this time. It can also be difficult to obtain accurate measurements of the caliber of the narrowed distal esophagus, which may vary based on the degree of distention of this segment, recognizing that differences in the measurement of the distal esophageal caliber could influence the findings of our study. Finally, there were variations in technique for performing the fluoroscopic examination, such as the volume of contrast material administered and the timing of image acquisition in this retrospective study. timed barium swallow performed using a standardized technique therefore might prove to be a more objective test for evaluating the findings on post-poem esophagrams [32 34]. In summary, POEM is a novel less-invasive procedure than is laparoscopic Heller myotomy for the treatment of achalasia, with fewer associated complications and shorter recovery times. 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