This section describes efficacy outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview. This evidence review included studies on patients with cricopharyngeal muscle dysfunction, it did not include studies that only reported the use of this procedure for Zenker's diverticulum. However, it does include mixed‑case series that included some patients with Zenker's diverticulum.
4.1 A case series of 87 patients with cricopharyngeal (CP) muscle dysfunction from a variety of causes, treated by carbon dioxide (CO2) laser CP myotomy, reported that the average Functional Outcome Swallowing Scale (FOSS) scores (on a scale 0–5, higher scores indicating non‑oral feeding) improved from 2.6 to 1.6 (p<0.001) after surgery (timing not reported). A retrospective comparative case series of 22 patients comparing CO2 laser CP myotomy (n=14) against transcervical CP myotomy (n=8) reported that the mean functional outcomes (FOSS scores) improved after the procedure in both groups (CO2 laser group improved from 2.4 to 0.9; transcervical group from 3.4 to 1.9, p values not reported).
4.2 A case series of 10 patients with dysphagia secondary to cricopharyngeal stricture after chemoradiation for squamous cell carcinoma of the head and neck, treated by CO2 laser CP myotomy reported improvement in dysphagia (assessed by modified Barium Swallow study) and radiographic resolution of the cricopharyngeal stricture in 90% (9/10) of patients.
4.3 The case series of 87 patients with cricopharyngeal dysfunction treated by endoscopic CO2 laser myotomy reported recurrence of dysphagia in 14% (12/87) of patients (timings not reported). All patients needed subsequent surgical procedures: 5 were treated by oesophageal dilation, 6 by repeat CO2 laser cricopharyngeal myotomy and one patient had several laser procedures and dilatations. A retrospective comparative case series of 153 patients who had endoscopic cricopharyngeal myotomy by either CO2 laser (n=123) or by stapler (n=23) reported that symptom recurrence was more frequent after the stapling procedure (CO2 laser group 6% (7/153), stapler group 26% (6/23); p=0.002). The rates of revision surgery were similar in the 2 groups (CO2 laser group 3% (4/123), stapler group 4% (1/23); p=0.77).
4.4 A case series of 65 patients reported that global satisfaction (self‑assessed on a scale of 0–10, with 10 being most satisfied) was 7.2, in the 30 patients who responded to the survey. 84% (27/32) of patients reported that they would have the procedure again if needed.
4.5 The specialist advisers listed key efficacy outcomes as improved swallowing and nutritional state, reduced number of aspirations and chest infections, reduced length of stay in hospital, improved patient‑reported quality of life measures (for example FOSS, EUR‑QoL), and changes in modified barium swallow study, videofluoroscopy or manometry.