Surgical interventions for pharyngeal pouch
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To determine the effectiveness and safety of various surgical interventions in the management of pharyngeal pouch.
Background
Pharyngeal pouch is an out‐pouching or pocket that develops from the posterior wall of the pharynx just above the entrance to the oesophagus (gullet). First described by Ludlow in 1769 (Ludlow 1769), the pouches are thought to arise because of spasm in the sphincter muscle at the top of the oesophagus (cricopharyngeus muscle). The muscles of the pharynx contract with the act of swallowing and pressure in the pharynx therefore increases. If the cricopharyngeus muscle does not open at the appropriate time, pressure builds up immediately above the cricopharyngeus muscle. There is a potential weakness in the posterior wall of the pharynx at 'Killian's dehiscence', between the cricopharyngeus and thyropharyngeus muscles. The pharyngeal wall may be pushed outwards and a pouch can develop.
Pouches are most commonly seen in the elderly and may remain asymptomatic. However, in some patients they may give rise to difficulty in swallowing and troublesome regurgitation of food. This can result in weight loss and/or recurrent chest infections. The diagnosis is usually confirmed radiologically with a barium swallow. When patients are symptomatic they may be offered surgical treatment.
There are various surgical procedures for pharyngeal pouch which can basically be divided into two types. In an open procedure the pouch is approached through a neck incision and excised (diverticulectomy), inverted (inversion) or suspended on the tissues posteriorly (diverticulopexy). The spasm induced by the cricopharyngeus muscle can be relieved by a cricopharyngeal myotomy. This procedure may be combined with an open procedure or it may be the only procedure required.
The second main type of surgery is the endoscopic procedure where the approach is transoral. The principle involves dividing the separating wall between the pouch and the oesophagus to convert it into one cavity. Many different modifications of the endoscopic procedure are now available, for example, diathermy, laser and endoscopic stapling. Endoscopic stapling has become increasingly popular in the last decade. This procedure not only cuts the dividing wall but also staples the divided edges thus theoretically reducing complications due to leakage into the mediastinum.
The optimal surgical management of pharyngeal pouch remains debatable. Over the 20th century the surgery for this condition has undergone a slow evolution from open procedures to the less invasive endoscopic approach. It is unclear which, if any, of these procedures is superior either in terms of improvement of symptoms or risk of complications.
With a dramatic increase in endoscopic procedures and a slow decline in open approach, it is now important that a systematic review of surgical interventions for pharyngeal pouch is conducted.
Objectives
To determine the effectiveness and safety of various surgical interventions in the management of pharyngeal pouch.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials (RCTs).
Case series comparing two or more interventions may be considered if no RCTs are available.
Studies in all languages will be considered.
Types of participants
Adults aged 18 or over with symptomatic pharyngeal pouch diagnosed and confirmed by barium swallow. Patients with re‐do procedures and those with other rare types of pouches (not Zenker's) will be excluded.
Types of interventions
Open procedures:
Diverticulectomy, diverticulopexy, diverticular invagination, cricopharyngeal myotomy.
Endoscopic procedures:
Diathermy, Argon plasma coagulation, CO2 laser, KTP/532 laser and stapling.
Types of outcome measures
PRIMARY OUTCOME MEASURE:
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Success rate, however determined.
SECONDARY OUTCOME MEASURES:
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Relation of pouch size to type of surgery;
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Recurrence rate, however determined;
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Number of re‐do procedures;
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Duration of hospital stay;
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Quality of life score (SF36 etc) e.g. dysphagia, regurgitation, cough, weight gain etc.
Cost effectiveness data will also be studied, where available.
ADVERSE EVENTS:
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Mortality rate (mortality at 30 days and at maximum follow‐up);
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Rate of complications.
Search methods for identification of studies
Trials will be identified from the Cochrane ENT Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE (1966 onwards) and EMBASE (1974 onwards) using the following search terms:
CENTRAL
#1 ZENKER DIVERTICULUM explode in all trees (MeSH)
#2 zenker*
#3 pharyngeal
#4 (oesophagopharyngeal or esophagopharnygeal)
#5 (oesophago‐pharyngeal or esophago‐pharyngeal)
#6 pharyngoesophageal
#7 (pharyngo‐oesophageal or pharyngo‐esophageal)
#8 (hypopharyngeal or hypo‐pharyngeal or hypopharynx or hypo‐pharynx)
#9 "PHARYNGEAL DISEASES" explode in all trees (MeSH)
#10 (#2 or #3 or #4 or #5 or #6 or #7 or #8 or #9)
#11 pouch
#12 (diverticula or diverticulum or diverticle or diverticulosis or
psuedodiverticulum or pseudo‐diverticulum)
#13 DIVERTICULUM explode in all trees (MeSH)
#14 (#11 or #12 or #13)
#15 (#10 and #14)
#16 (#1 or #15)
MEDLINE
#1 Zenker‐Diverticulum/
#2 zenker*
#3 pharyngeal
#4 (oesophagopharyngeal or esophagopharnygeal)
#5 (oesophago‐pharyngeal or esophago‐pharyngeal)
#6 pharyngoesophageal
#7 (pharyngo‐oesophageal or pharyngo‐esophageal)
#8 (hypopharyngeal or hypo‐pharyngeal or hypopharynx or hypo‐pharynx)
#9 exp "Pharyngeal Diseases"/
#10 (#2 or #3 or #4 or #5 or #6 or #7 or #8 or #9)
#11 pouch
#12 (diverticula or diverticulum or diverticle or diverticulosis or
pseudodiverticulum or pseudo‐diverticulum)
#13 exp diverticulum/
#14 (#11 or #12 or #13)
#15 (#10 and #14)
#16 (#1 or #15)
EMBASE
#1 Zenker‐Diverticulum/
#2 zenker*
#3 pharyngeal
#4 (oesophagopharyngeal or esophagopharnygeal)
#5 (oesophago‐pharyngeal or esophago‐pharyngeal)
#6 pharyngoesophageal
#7 (pharyngo‐oesophageal or pharyngo‐esophageal)
#8 (hypopharyngeal or hypo‐pharyngeal or hypopharynx or hypo‐pharynx)
#9 exp Pharynx Disease/
#10 (#2 or #3 or #4 or #5 or #6 or #7 or #8 or #9)
#11 pouch
#12 (diverticula or diverticulum or diverticle or diverticulosis or
pseudodiverticulum or pseudo‐diverticulum)
#13 exp Diverticulosis/
#14 (#11 or #12 or #13)
#15 (#10 and #14)
#16 (#1 or #15)
Reference lists of all identified trials and previous reviews will be searched for additional trials. Further electronic searches for key authors identified will be made. They will be asked to identify additional published or unpublished trials. There will be no language restrictions.
Data collection and analysis
STUDY SELECTION
Each author will independently assess eligibility of retrieved reports and extract data. The results will be compared and any difference will be resolved by discussion and consensus. If the reviewers agree that none of the studies fit the entry criteria, additional analysis considering all studies as observational may have to be done. Trials identified for inclusion will be collated (PS, DL) and the methods and result section will be re‐sent to the three reviewers (PS, DL, TF) for assessment and validation. Endoscopic procedures that are converted to open procedures will be included in the endoscopic procedures on an intention to treat basis.
QUALITY ASSESSMENT
Each author will review the methodological quality of each trial independently. This includes assessment of inclusion criteria, randomisation, allocation, interventions, outcome measures and follow up. Where required, additional information will be sought from trial authors to clarify methodology (Handbook 2003).
DATA EXTRACTION
The standard data extraction form will include at least the following items:
1. General information: title, authors, source, contact address, country, language of publication, year of publication, setting;
2. Method: duration, randomisation technique, allocation concealment method, blinding (in this study patients and provider cannot be blinded so only blinding of outcome assessors will be noted);
3. Participants: sampling (random/convenience), number in comparison groups, age, sex, similarity of groups at baseline, withdrawals/losses to follow‐up (reason), subgroups;
4. Interventions: types of interventions (open, endoscopic);
5. Outcomes: outcomes specified above, any other outcomes assessed, size of pouches, other events, times of assessment, length of follow‐up;
6. Notes: funding sources.
Three reviewers will independently extract the data onto paper data collection forms and then double‐enter the data into RevMan 4.2. Differences in data extraction will be resolved by consensus, referring back to original article. When necessary, information will be sought from the authors of the original articles.
DATA ANALYSIS AND SYNTHESIS
Data will be summarised statistically if they are available and of sufficient quality. We expect both dichotomous and continuous data. Dichotomous data in case control series will be expressed as odd ratios (OR) and relative risk (RR) in randomised controlled trials (Deeks 1998). Number needed to treat (NNT) will be calculated. Continuous data will be expressed as weighted mean difference (WMD). Overall results will be calculated based on a random effect model. Where it is appropriate to pool results, we will use a fixed effect model if there are low numbers of trials in each comparison.
We will assess heterogeneity between trial results using a chi‐square test and visual inspection of a forest plot as calculated by RevMan. If significant heterogeneity is found between trials, careful examinations of reasons for these differences will be looked for in the trials. Any resulting post‐hoc subgroup analysis will be clearly stated and explained.
SENSITIVITY ANALYSIS
Sensitivity analyses will be conducted to determine the impact of changes in inclusion criteria such as:
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Exclusion of lower quality methodological studies;
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Exclusion of trials using filters: diagnostic criteria, concomitant treatment, comorbidity, re‐do procedures.
