Over the past decade, endoscopic cricopharyngeal myotomy (ECPM) using a laser1 has been introduced as an alternative surgical procedure to transcervical cricopharyngeal myotomy (TCPM).2 Although a wide resection of cricopharyngeal muscle with TCPM has sufficient potential to improve cricopharyngeal dysphagia, it has often carried surgical morbidity and complication compared with ECPM.3 However, ECPM is not yet widely done because of its rather highly qualified technique. It is likely that this endoscopic technique of posterior vertical myotomy alone does not provide sufficient opening of the upper esophageal sphincter due to postoperative adhesion of the cricopharyngeal muscle. Therefore, in this surgical procedure against cricopharyngeal dysphagia, not only myotomy but also resection of the cricopharyngeal muscle is highly required. We present a new paradigm of ECPM and discuss its advantages and applications.
The surgical procedure used for the cricopharyngeal dysphagia in our institution is a modification of conventional ECPM consisting of the following steps:
1A Weerda distending operating laryngoscope (Karl Storz, Tuttlingen, Germany) is placed at the postcricoid position (Fig. 1A).
2A vertical midline incision is made in the mucosa covering the cricopharyngeal muscle with a CO2 laser (Fig. 1B), and the muscle is well exposed under a microscope.
3While grasping the cricopharyngeal muscle, its posterior aspect is widely separated from the buccopharyngeal fascia (Fig. 1C). A submucosal resection of the cricopharyngeal muscle is then made with the CO2 laser as widely as possible (Fig. 1D and 1E).
4The resected area is covered with the mucosa and the initial mucosal incision is sutured horizontally by interrupted 4-0 Vicryl sutures (Ethicon Inc., Somerville, NJ). Consequently the esophageal introitus is enlarged (Fig. 1F).
Points to Notice
•To make a minimum mucosal incision.
•To avoid damage to the buccopharyngeal fascia.
•To grasp the cricopharyngeal muscle with two cramps and keep traction on it.
•To precisely resect the muscle that causes the stricture.
•To approximate the covered mucosa and to avoid a dead space in the resected area.
A 75-year-old woman visited our hospital because of suffering from a mild dysphagia for three years. Laryngoscopy revealed significant salivary retention in the piriform sinuses. In videofluorography, the contrast medium did not pass easily through the upper esophageal sphincter because the cricopharyngeal opening was not sufficient, and a cricopharyngeal bar presented at the level of cricopharyngeal region (Fig. 2A). The patient was diagnosed with cricopharyngeal dysphagia, and the ECPM was performed according to above technique.
In videofluorography of postoperative day 5, a cricopharyngeal bar disappeared, and the passage of contrast medium at the level of cricopharyngeal region recovered (Fig. 2B). The patient's feeding tube was removed, and a full liquid diet was successfully started and continuously swallowed. On postoperative day 10, a regular diet was begun. Laryngoscopy revealed no salivary retention in the piriform sinuses on postoperative day 14. The patient has been symptom-free for 10 months.
The histopathologic findings of the cricopharyngeal muscle are shown in Fig. 3. Atrophic musclar fibers of various sizes, granulations, and stromal fibrosis were identified. There was little infiltration of inflammatory cells. These findings are compatible with cricopharyngeal myopathy.
Although the TCPM has sufficient potential to improve cricopharyngeal dysphagia, there have been several technical problems. In this procedure, even if using a microscope, it is difficult to distinguish the boundary between the cricopharyngeal muscle and thyropharyngeal muscle, or esophageal muscle. Although the cricopharyngeal muscle is exactly identified, it is necessary to confirm the origin of cricopharyngeal muscle on the cricoid cartilage. In the actual surgical procedure, the origin of the muscle is not easily identified due to the interrupting view by the thyroid gland, the superior thyroid artery, and other structures. Therefore, cricopharyngeal muscle has to be resected widely including both parts of the lower thyropharyngeal muscle and the upper esophageal muscle. Moreover, in this transcervical procedure, the injury to the recurrent nerve or the disorder of laryngeal elevation by the postoperative scar might possibly occur.
The ECPM is obviously a less invasive technique and requires less operating time than the TCPM.3–5 The mucosa-covered cricopharyngeal muscle is easily identified as the mound of tissue just proximal to the esophageal introitus (Fig. 1A)1, 3 and is able to selectively cut off the horizontal part of the cricopharyngeal muscle that is absent of the median pharyngeal raphe.6 The resection of the horizontal part alone will have a sufficient effect for such conditions as Zenker's diverticulum.4 But if a sufficient opening by this part's resection (Fig. 4A) is not acquired, the resection of the oblique part of the cricopharygneal muscle can be added upwards a little (Fig. 4B). Thus, the direct visualization of the upper esophageal sphincter makes it easy to ensure transection of every fiber of the cricopharyngeal muscle, confirming the intraluminal diameter and the intrinsic compression before and after myotomy.
In the ECPM, however, the myotomy alone and the vertical mucosal incision might cause the postoperative stenosis by the postoperative adhesion of the cricopharyngeal muscle and the mucosal scar, respectively. Therefore, on the occasion of performing ECPM, not only myotomy but also resection of the cricopharyngeal muscle is highly required, and the initial mucosal incision should be sutured horizontally. Moreover, in order to not damage the fascia by a laser, a wide separation of the cricopharyngeal muscle from the fascia is needed before using a laser. The ensured preservation of the buccopharyngeal fascia hardly causes postoperative leakage to the neck.3 Most series of ECPM have reported few major complications including cervical infection. The buccopharyngeal fascia is an important layer that protects the retropharyngeal space from spreading pharyngeal contents.
Currently cricopharyngeal myotomy has limited indications based primarily on cricopharyngeal dysphagia. It is recommended that the ECPM technique is performed for an unequivocal diagnosis of cricopharyngeal dysphagia made by radiographic findings or manometry. However, in cases of the additional laryngeal suspension, it may be necessary to select the classic TCPM rather than ECPM if wider resection of the cricopharyngeal muscle is needed.
The ECPM is less invasive and results in fewer complications than the classic TCPM. Furthermore, this endoscopic technique presented here will provide a more sufficient opening of the upper esophageal sphincter by eliminating the problem of postoperative cricopharyngeal stenosis.