World J Surg (2009) 33:2557-2566
DOI 10.1007/s00268-009-0104-5
Systematic Review and Meta-Analysis of Chewing-Gum Therapy
in the Reduction of Postoperative Paralytic Ileus Following
Gastrointestinal Surgery
J. Edward F. Fitzgerald AE Irfan Ahmed
Published online: 10 September 2009
O Societe Internationale de Chirurgie 2009
Abstract
WMD of 12.6 h (17%) reduction (95% CI -21.49 to
Background
Postoperative ileus has long been considered
-3.72; P = 0.005). For time to first bowel motion, treat-
an inevitable consequence of gastrointestinal surgery. It
ment was favored with a WMD of 23.11 h (22%) reduction
prolongs hospital stay, increases morbidity, and adds to
(95% CI -34.32 to -11.91; P \ 0.001). For length of stay,
treatment costs. Chewing is a form of sham feeding
the analysis showed a nonsignificant trend toward treat-
reported to stimulate bowel motility. This analysis exam-
ment with WMD of 23.88 h (12%) reduction (95% CI
ines the value of chewing-gum therapy in treatment of
-53.29 to ?5.53; P = 0.11). There were no significant
postoperative ileus.
differences in complication rates.
Methods
A search for randomized, controlled trials
Conclusions
Chewing-gum therapy following open gas-
studying elective gastrointestinal surgery was undertaken
trointestinal surgery is beneficial in reducing the period of
using MEDLINE, Embase, Cochrane Controlled Trials
postoperative ileus, although without a significant reduc-
Register, and reference lists. Outcomes were extracted
tion in length of hospital stay. These outcomes are not
including time to first flatus and bowel motion, length of
significant for laparoscopic gastrointestinal surgery.
stay, and complications. Statistical analysis was undertaken
using the weighted mean difference (WMD) and random-
effects model with 95% confidence intervals (CI).
Introduction
Results
Seven studies with 272 patients were included.
For time to first flatus the analysis favored treatment with a
Postoperative ileus has long been considered an inevitable
consequence of abdominal surgery. It has been defined as
``transient cessation of coordinated bowel motility after
Electronic supplementary material
The online version of this
surgical intervention, which prevents effective transit of
article (doi:10.1007/s00268-009-0104-5) contains supplementary
intestinal contents and/or tolerance of intake'' [1]. To the
material, which is available to authorized users.
patient, this translates as delayed recovery and prolonged
J. E. F. Fitzgerald (&)
hospital stay. Symptoms are characterized by nausea,
Department of Gastrointestinal Surgery, Queen's Medical
vomiting, abdominal distension, pain, inability to tolerate
Centre, Nottingham University Hospitals NHS Trust,
an oral diet, and a delay in the return of normal gastroin-
Nottingham NG7 2UH, UK
e-mail: edwardfitzgerald@doctors.org.uk
testinal function with the passage of flatus and stool.
In addition to increased patient morbidity, the economic
I. Ahmed
burden of this lengthened hospital stay is substantial. In one
Department of Surgery, Aberdeen Royal Infirmary, Aberdeen
review of patients undergoing hemicolectomy, prolonged
AB25 2ZA, Scotland
postoperative ileus increased the duration of hospitalization
Present Address:
by an average of 8 days with additional median costs of
J. E. F. Fitzgerald
$14,904 [2]. Previous studies estimated overall annual
Medical Education Unit, University of Nottingham Medical
health care expenditure in relation to postoperative ileus at
School, Queens Medical Centre, Derby Road, Nottingham NG7
2UH, UK
between $750 million and $1 billion in the United States
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World J Surg (2009) 33:2557-2566
[3]. Despite this, research has shown wide variations
Study selection
between surgeons with regard to awareness, recognition,
and management of this condition [4].
Eligible trials were those in which adult patients had
The treatment of postoperative ileus has traditionally
undergone elective open or laparoscopic gastrointestinal
been supportive, with nasogastric decompression, intrave-
surgery for any indication. The intervention was postop-
nous fluids, and watchful waiting. However, the widespread
erative gum-chewing versus no additional treatment (rou-
introduction of enhanced patient recovery protocols has
tine postoperative care). Only trials using a randomized,
driven new research in this area, focusing on mechanisms
controlled methodology were included. Demographics,
and treatments for this major cause of delayed discharge.
pre- and postoperative protocols, and the nature of the
Although the etiology of postoperative ileus is not fully
operations were recorded. Primary and secondary end-
understood, research has suggested numerous contributing
points were identified, including time to first flatus, time to
factors, including pharmacologic (e.g., general anesthetic
first bowel opening, length of hospital stay, and 30-day
and opioid analgesia), inflammatory causes (e.g., bowel
postoperative complications. Predefined exclusion criteria
manipulation and inflammatory mediator release), and
included poor methodology such that a study could not be
neural reflexes (postoperative sympathetic overactivity or
adequately compared or where data was presented in a
other inhibitory neuronal pathways) [5, 6]. It seems likely
format that rendered meta-analysis impossible (once
that the etiology is multifactorial and varies according to
attempts to obtain raw data from the authors failed).
the original insult, as evidenced by the varying success of
treatments specifically targeting these individual causes.
Validity assessment
One of these treatments is based on the physiologic
theory of ``sham feeding.'' Cephalic-vagal stimulation from
Both authors scored papers on methodological quality
chewing alone gives rise to propulsive and hormonal gas-
using the five-point Jadad scale [21]. Assessment was blind
trointestinal activity similar to that seen with normal eating
to both authors and institution. There was no disagreement
[7]. Although early enteral feeding has also been shown to
on scoring.
be beneficial, the effect on postoperative ileus varies and
patient intolerance is high, especially following gastroin-
Data abstraction and study characteristics
testinal surgery [8-10]. Several studies have tested the
sham feeding hypothesis by using chewing-gum during the
Data were checked in duplicate by both authors using a
early postoperative period [11-18]. It has the advantage of
standard form. The study method and outcomes were tab-
being inexpensive, well tolerated, and widely available.
ulated for comparison.
The objective of this review was to identify clinical
trials of chewing-gum therapy in relation to postoperative
Data analysis
ileus and analyze results by meta-analysis to show what
benefit, if any, this may bring in providing a simple solu-
Time to first flatus, time to first bowel movement, length of
tion to ameliorate an old problem.
stay, and complications were identified as continuous
variables. Statistical analysis of the combined results was
undertaken with a standard meta-analysis software package
Methods
(Review Manager 4.2; Nordic Cochrane Centre, Cochrane
Collaboration, Oxford, UK, 2003). The weighted mean
Methodology for the meta-analysis was undertaken in
difference (WMD) and random-effects model were used
accordance with the proposals outlined in the QUOROM
owing to the heterogeneity of the clinical trials examined.
statement [19] and the Cochrane Handbook for Systematic
Data outcomes were presented with 95% confidence
Reviews of Intervention [20].
intervals (CI).
Identification of trials
A search using MEDLINE, Embase, and the Cochrane
Results
Controlled Trials Register were undertaken using the terms
``ileus,'' ``gum,'' ``chewing,'' ``motility,'' and ``recovery''
Trial characteristics
both alone and in combinations. No year limits or language
restrictions were applied. To ensure all relevant articles
We identified 10 trials that had investigated the effects of
were reviewed, the reference lists of the articles identified
chewing-gum on postoperative ileus, and all were retrieved
in this search were also included.
for further detailed evaluation. One sequential case series
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World J Surg (2009) 33:2557-2566
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investigating the effect of gum chewing in patients
Trial flow
undergoing urologic ileal conduit surgery was immediately
excluded owing to nonrandomized methodology [22]. One
Trial methodology
study investigating undefined gastrointestinal surgery
solely on children was also excluded [23]. Of those
Three trials clearly stated their methodology for randomi-
remaining, all were randomized, controlled trials with
zation: sealed envelope [12], randomized card-pull design
variable attempts at blinding. All studies stated the demo-
[11, 14], or computer-generated randomization, respec-
graphic attributes of enrolled patients, and they were
tively [13]. One article described attempts at blinding and
broadly comparable. One study examined recovery fol-
was also the only study to include a placebo group [13].
lowing subtotal gastrectomy [11], with the remainder in the
setting of colonic surgery. One study did not publish
Outcomes
associated standard deviations alongside the relevant
results and was subsequently excluded as we were unable
All studies included in the analysis measured time to
to obtain this data from the authors [16]. One study pub-
passage of first flatus as an outcome (Fig. 1). A total of 144
lished median endpoints rather than the mean [13]; the
patients were in the treatment group and 128 in the control.
authors were subsequently able to provide appropriate data
The test for overall effect favored treatment, with a WMD
for time to first flatus and length of stay but not for time to
of 12.6 h reduction (95% CI -21.49 to -3.72; P = 0.005)
first bowel motion.
in time to flatus. This represents a 17% reduction in
The seven analyzed studies consisted of six published
comparison to the control group. However, it should be
articles [11-15, 18] and one abstract [17]. A total of 272
noted that five of the trial groups have 95% CI crossing the
patients were enrolled; they were a mix of patients
zero level.
undergoing surgery for benign and elective conditions.
All but one study [15] measured time to first bowel
Operations were performed via open surgery [12-15],
motion as an outcome. One study did not provide sufficient
laparoscopic techniques [18], or both [17]. One study
data for inclusion [13]. Of the remaining, 122 patients were
presented results for open and laparoscopic trial arms
enrolled in a treatment group and 107 in a control group.
separately [17], and so these were analyzed in the meta-
The results are shown in Fig. 2. The test for overall effect
analysis as separate groups. One study did not clearly state
favored treatment, with a WMD of 23.11 h reduction in
whether patients underwent open or laparoscopic surgery
time to bowel opening (95% CI -34.32 to -11.91;
[11].
P \ 0.0001). This represents a 22% reduction in compar-
All seven eligible studies included time to first flatus and
ison to the control group. However, four of the trial groups
time to first bowel motion as primary outcomes. All but
had 95% confidence intervals crossing the zero level.
one trial documented the length of stay [15]. There was
All but one study [15] included length of stay as an
variation in the units of reporting, with three studies
outcome. The results are shown in Fig. 3. A total of 134
recording outcomes in hours and three in days. All were
patients were enrolled in the treatment group and 114 in the
converted to hours to allow uniform analysis.
control group. The test for overall effect showed a non-
Postoperative protocols differed among the studies. Of
statistically significant trend toward treatment, with a
the included studies, three specified the make of gum used
WMD of 23.88 h reduction in time to bowel opening (95%
[12, 15, 18] and two listed nutritional ingredients without
CI -53.29 to ?5.53; P = 0.11). This represents a 12%
specifying the commercial brand [11, 13]. Gum chewing
reduction in comparison to the control group. However, six
was uniformly commenced on postoperative day 1. Both
of the trial groups have 95% confidence intervals crossing
daily duration and frequency of chewing were docu-
the zero level.
mented in five studies [11-13, 15, 17], varying between 5
All but two studies [11, 17] included 30-day postoper-
and 30 min chewing three or four times a day. Two
ative complications as an outcome. A summary is shown in
studies stated only frequency, not duration [14, 18].
Table 1. Complications were counted separately and not
Postoperative feeding regimens varied among studies.
related to individual patients experiencing them. As such,
One study favored traditional ``sips'' until passage of first
statistical analysis of significance between these groups is
flatus [13]; the others did not state the protocol. For
not valid.
colonic surgery, only one study stated whether bowel
preparation had been used prior to colonic surgery [12].
Subgroup analysis
Three studies stated the protocol for postoperative anal-
gesia [11-13]; two did not mention it specifically [15,
Given the variation in surgical interventions used in these
18], and one study stated ``standard operating consultant
randomized controlled trials, the meta-analysis was repe-
preference'' [14].
ated omitting the small number of studies that utilized
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World J Surg (2009) 33:2557-2566
motion
flatus
bowel
first
first
to
to
time
time
of
of
plot
plot
Forrest
Forrest
1
2
Fig.
Fig.
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World J Surg (2009) 33:2557-2566
2561
laparoscopic surgery or did not specify [11, 18]. One study
reported these results separately, enabling only the open
surgery outcomes to be included [17]. The meta-analysis
findings based purely on outcomes from open and laparo-
scopic surgery are shown in Table 2. There was no statis-
tically significant difference between them (chi-squared
test, P = 0.192).
Statistical notes
Further analysis of these findings based on all included
studies with a fixed effect model did not materially change
the outcomes of this analysis for time to first flatus or
bowel motion. As such, the fixed effect model was used to
examine these studies for publication bias with a funnel
plot (Figs. 4, 5). This has suggested the possibility of a
publication bias toward a positive effect. However, this
must be set against the heterogeneity of the clinical trials
examined. Egger's linear regression test was not used
owing to the small number of studies in this analysis.
Discussion
This study systematically reviewed the effects of gum-
chewing for postoperative treatment of ileus following
gastrointestinal surgery and highlights the potential bene-
fits of its use. It confirmed the findings of previous smaller
published meta-analyses [24, 25], and for the first time the
larger pooled results allow a detailed subgroup analysis of
comparative outcomes based on surgical modality.
For more than a century this condition has challenged
both patients and surgeons. The clinical and economic
burden is substantial, encompassing delayed discharge,
increased bed occupation, prolonged nursing time, and
decreased patient satisfaction [26].
Current research theories regarding the etiology of
postoperative ileus describe a biphasic pathologic reaction
in the affected bowel. Initial mechanical factors, such as
operative handling, result in activation of neural reflexes
suppressing bowel motility via the sympathetic adrenergic
pathway [27] and stimulating release of corticotropin-
releasing factor [28]. These effects last a number of hours,
stay
after which a second inflammatory response dominates.
of
Interestingly, this also appears to be neurologically regu-
lated. Recent studies suggest that efferent vagal nerve
length
output reduces the inflammatory response through activa-
of
tion of nicotinic acetylcholine receptors on macrophage
plot
immune cells. This cholinergic antiinflammatory pathway
has been demonstrated in rodent models [29] and may also
Forrest
contribute to other abdominal inflammatory disorders.
3
Over recent decades several drug therapies have been
Fig.
promoted as potentially beneficial in the amelioration of
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World J Surg (2009) 33:2557-2566
postoperative ileus. A recent Cochrane review of prokinetic
achievable and would lend weight to the findings. Another
agents in this setting studied 39 randomized controlled
weakness is the widespread lack of standardization or
trials and showed that the use of many of these agents
description of perioperative care regimens. Given the
(including erythromycin, cholecystokinin, cisapride, and
known effects of opioids [35], epidural analgesia [36], and
dopamine antagonists) is not supported by the available
early enteral feeding [8-10] on subsequent patient recovery
evidence [30].
and postoperative ileus, it is unfortunate that several studies
As a result of new research into gastrointestinal motility,
did not state postoperative practice in this respect. Equally,
a number of novel pharmacologic therapies for postoper-
no definitions of discharge criteria were given in any of the
ative ileus are in development. Among them, only two have
studies to help interpret length of stay outcomes. This is
reached clinical trials; and both seek to antagonize the Mu-
particularly noticeable in the study by Asao et al., where
opioid receptor in the gastrointestinal tract. Both endoge-
despite patients undergoing laparoscopic colorectal surgery
nous and exogenous opioids are known to mediate reduced
the mean length of stay was unusually long (mean
motility through their actions on gastrointestinal smooth
13.5 days for gum-chewing cohort, 14.5 days for the con-
muscle via this receptor. Previous difficulties in developing
trol group). Clarification was later published in which the
selective targets have been overcome, and two therapies
author attributes this to the nature of private health insur-
that avoid antagonizing the beneficial effects of opioid-
ance specific to the Japanese medical system [37].
based analgesia have now reached Phase III trials [31].
One study (Kouba et al.) was excluded from our analysis
Methylnaltrexone (Progenics Pharmaceuticals, Tarrytown,
because of its nonrandomized methodology [22] and
NY, USA) is a selective derivative of naltrexone under-
another (Schluender et al.) because of insufficient data
going evaluation in a randomized, double-blind trial of
[16]. The results of Kouba et al. appear to add limited
postcolectomy patients. Compared with placebo, methyln-
support to our findings in patients undergoing postradical
altrexone significantly reduces morphine-induced delay in
cystectomy and urinary diversion. As the authors high-
the gastrointestinal transit time and the peripheral side
lighted, this operation is suitable for comparison in that
effects of morphine therapy [32, 33].
urinary diversion involves harvesting a segment of bowel
Alvimopan (Adolor, Exton, PA, USA) is a quaternary
with associated reanastamosis. In comparison to control
Mu-opioid receptor antagonist with a higher binding
patients, time to flatus (2.4 vs. 2.9 days; P \ 0.001) and
affinity than methylnaltrexone. A recent pooled analysis of
first bowel motion (3.2 vs. 3.9 days; P \ 0.001) showed a
Phase III trials studying its role in postoperative ileus has
clinically significant reduction in the treatment group.
shown a clinically significant reduction in length of stay
Length of stay was not significantly different with respect
and postoperative morbidity rates [34]. However, a non-
to controls (4.7 vs. 5.1 days; P = 0.067). Given that this
significant increase in the frequency of cardiovascular side
was the largest study thus far, enrolling a total of 102
effects has resulted in the U.S. Food and Drug Adminis-
patients, it is disappointing that randomized, controlled
tration requesting further risk analysis prior to review [31].
trial methodology was not implemented.
Our analysis suggests beneficial effects from a consid-
In contrast, the second study excluded in our analysis
erably simpler and cheaper treatment strategy. However,
did not support our findings. Schluender et al. enrolled 28
the findings are limited by the small sample sizes. This
patients undergoing elective colonic surgery [16]. Twenty
potentially leads to a large variability in treatment effects
of them underwent open surgery, and eight underwent
due to random chance and so may overstate the findings.
laparoscopic surgery; the results for the cohorts were
As with all studies of this nature, we are also open to risk of
analyzed separately. Although a trend toward shorter
publication bias from the nonpublication of literature with
length of stay was seen in patients who participated in
negative findings in this area, as suggested by the funnel
chewing gum therapy and underwent laparoscopic surgery,
plots (Figs. 4, 5).
none of the results of this study were significant.
Several important methodological deficiencies were
As this latter study demonstrated, a further potential
highlighted in the published research included in this
confounder is the differing operations, indications, and
analysis. Only one study included a placebo group to
pathologies included in the trials. Laparoscopic surgery is
quantify the treatment effect [13], but because of their
known to reduce the inflammatory response and in so doing
differing method of reporting results not all of their data
promote a faster recovery [38]. Both case-matched studies
could be included in our analysis. The study failed to report
and randomized controlled trials suggest a significant
a statistical difference but showed a trend in favor of gum
reduction in length of hospital stay for laparoscopy-assisted
chewing. Another potential weakness is the lack of blind-
colonic surgery versus the traditional open technique [39,
ing in most studies, with potential bias by the surgical
40]. These different surgical interventions may cause var-
teams recording results. Blinding the participants would be
iation in outcomes given the differing magnitude of ileus
difficult in this setting; however, blinding the observers is
likely to result from open or laparoscopic procedures.
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World J Surg (2009) 33:2557-2566
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Table 1 Summary of postoperative complications
Study
Control group complications
Treatment group complications
Total events
Total patients
Total events
Total patients
Quah et al. [12]
14
19
15
19
Matros et al. [13]
10
21
4
22
Schuster et al. [14]
2
17
1
17
Hirayama et al. [15]
7
14
4
10
Asao et al. [18]
1
9
0
10
Table 2 Clinical outcomes in comparison to control groups (unspecified trials excluded)
Outcome
All included trials
Open surgery only
Laparoscopic surgery only
Reduction
% Reduction
P
Reduction
% Reduction
P
Reduction
% Reduction
P
(weighted mean
compared to
(weighted mean
compared to
(weighted mean
compared to
difference)
control
difference)
control
difference)
control
Time to first
12.6
17
0.005 13.24
18
0.03
15.78
12
0.14
flatus (hours)
Time to first
23.11
22
\ 0.001 21.73
21
0.002 37.65
17
0.11
bowel
opening
(hours)
Length of stay
23.88
12
0.11
25.17
15
0.24
30.55
6
0.06
(hours)
Interestingly, the study by McCormick et al. [17] dem-
disorganized migrating motor complexes result in a lack of
onstrated a benefit from chewing-gum therapy in the group
coordinated propulsion in intestinal and colonic smooth
treated laparoscopically but not in the group treated with
muscles. Spontaneous recovery usually occurs within 2-
open surgery. Likewise, a clear benefit was shown in the
4 days, although it takes significantly longer in some
study by Asao et al. [18], where all patients underwent the
patients. Recovery is also dependent on the segment of
laparoscopic technique. As previously described, the
affected bowel. Motility in the small intestine usually
excluded study from Schluender et al. also described a
returns to normal within 6-8 h, whereas that in the stomach
trend toward reduced length of stay for patients given
may take 1-2 days and in the colon up to 6 days [42].
chewing-gum therapy who underwent laparoscopic colonic
With this in mind, it is interesting to note the results of
surgery, which was not seen in the open surgery cohort.
Chou et al., who looked specifically at effects of gum-
Unfortunately, these results could not be included due to
chewing after subtotal gastrectomy. Their study failed to
insufficient data for analysis. However, these findings
show a difference in bowel recovery and therefore supports
suggest that the pathophysiologic changes in gastrointes-
the cephalic-vagal reflex as a significant component of the
tinal motility resulting from open surgery may be more
sham-feeding effect. However, to our knowledge no recent
profound or complex than that generated by laparoscopic
studies have sought to investigate these factors further.
surgery--and thus more difficult to overcome with chew-
Despite these findings, recent research suggests that the
ing-gum therapy. However, our subgroup analysis com-
well described cephalic-vagal reflex may not fully explain
paring laparoscopic with open surgery did not find a
the changes in gastrointestinal motility associated with
statistically significant difference between the results of
gum chewing. Sorbitol and other hexitols are common
these studies, although the laparoscopic surgery outcomes
ingredients of sugar-free chewing gums and may act as
were nonsignificant when considered on their own.
osmotic laxitives, accelerating return of gastrointestinal
Based on our existing knowledge of gastrointestinal
motility [43]. It is regrettable that so few of the studies
motility and the factors affecting it, it is no surprise that
specified brand or ingredients in the gum used. Other
gum-chewing, as a form of sham feeding, influences gut
research suggests that the role and rate of gum chewing act
function
[41].
After
major
gastrointestinal
surgery,
in an anxiolytic manner, with reduced systemic levels of
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World J Surg (2009) 33:2557-2566
Fig. 4 Funnel plot of time to
first flatus illustrating the degree
of standard error by effect size
Fig. 5 Funnel plot of time to
first bowel opening illustrating
the degree of standard error by
effect size
cortisol stress hormones [44, 45]. It is likely that the overall
highlight risks of bowel obstruction from swallowed gum
effects of gum chewing on gastrointestinal motility are
[48], and cardiac arrest secondary to airway obstruction
multimodal and not yet fully understood. However, other
from inhaled gum has also been reported [49, 50].
groups are now exploiting the positive effect of gum
Chewing-gum ingredients have been implicated in the
chewing on gastrointestinal motility in other clinical set-
causation of headaches (from aspartame, an artificial
tings by successfully accelerating the transit time for cap-
sweetner) [51], toxidermic vasculitis (from butylhydr-
sule endoscopy [46].
oxytoluene, a preservative) [52], and chronic diarrhea and
Although the articles reviewed in our analysis report
weight loss (from sorbitol, a sweetener and emulsifier)
similar complication rates among the study and control
[53].
groups, it is important to note that chewing gum itself is
Consideration of these risks must be balanced against
not a risk-free therapy. The act of gum chewing has been
potential benefits. Postoperative sedation may render
shown to reduce short-term appetite through orosensory
patients at higher risk of aspiration, and a history of
stimulation [47], which may have an effect on a patient's
allergy or hypersensitivity to ingredients must act as a
desire to recommence a normal diet. Several case reports
contraindication.
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World J Surg (2009) 33:2557-2566
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Conclusions
12. Quah H, Samad A, Neathey A et al (2006) Gum chewing and
postoperative ileus following open colectomy. Colorectal Dis
8:64-70
Our meta-analysis has shown that chewing gum during the
13. Matros E, Rocha F, Zinner M et al (2006) Does gum chewing
postoperative period leads to a clinically significant
ameliorate postoperative ileus? Results of a prospective, ran-
reduction in time to passage of first flatus, time to first
domized, placebo-controlled trial. J Am Coll Surg 202:773-778
bowel motion, and a nonstatistically significant reduction
14. Schuster R, Grewal N, Greaney GC et al (2006) Gum chewing
reduces ileus after elective open sigmoid colectomy. Arch Surg
in the length of inpatient stay following open gastrointes-
141:174-176
tinal surgery. The validity of these conclusions is limited
15. Hirayama I, Suzuki M, Ide M et al (2006) Gum-chewing stimu-
by the small number of trials available and their underlying
lates bowel motility after surgery for colorectal cancer. Hepato-
heterogeneity. In addition, gum chewing may bring its own
gastroenterology 53:206-208
16. Schluender S, Gurland B, Divino C et al (2005) Gum chewing
complications, and caution is therefore advised when
does not enhance the return of bowel function in patients
introducing this therapy without considering the potential
undergoing elective colon resection in a randomized blinded pilot
risks. We suggest that a large-scale randomized, placebo-
study. Colorectal Dis 92(Suppl 1):P143
controlled, multicenter trial is warranted to further inves-
17. McCormick J, Garvin R, Caushaj P et al (2005) The effects of
gum-chewing on bowel function and hospital stay after laparo-
tigate the relevance of chewing gum in the treatment of
scopic vs open colectomy: a multi-institution prospective ran-
postoperative ileus. In addition, we reiterate the importance
domized trial. J Am Coll Surg 201(Suppl 1):66-67
of investigators clearly defining, implementing, and
18. Asao T, Kuwano H, Nakamura J et al (2002) Gum chewing
reporting their studies in line with the CONSORT state-
enhances early recovery from postoperative ileus after laparo-
scopic colectomy. J Am Coll Surg 195:30-32
ment [54].
19. Moher D, Cook DJ, Eastwood S et al (1999) Improving the
Neither author has any competing academic, personal,
quality of reports of meta-analyses of randomised controlled
or commercial interests to declare. No funding was applied
trials: the QUOROM statement--quality of reporting of meta-
for or received in relation to the preparation of this
analyses. Lancet 354:1896-1900
20. Higgins J, Green S (2006) Cochrane handbook for systematic
manuscript.
reviews of intervention, version 4.2.6, 4th edn. Cochrane Col-
laboration Secretariat, Oxford, UK
21. Jadad AR, Moore RA, Carroll D et al (1996) Assessing the
quality of reports of randomized clinical trials: is blinding nec-
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Document Outline

• Systematic Review and Meta-Analysis of Chewing-Gum Therapy in the Reduction of Postoperative Paralytic Ileus Following Gastrointestinal Surgery
  • Abstract
    • Background
    • Methods
    • Results
    • Conclusions
  • Introduction
  • Methods
    • Identification of trials
    • Study selection
    • Validity assessment
    • Data abstraction and study characteristics
    • Data analysis
  • Results
    • Trial characteristics
    • Trial flow
      • Trial methodology
      • Outcomes
    • Subgroup analysis
    • Statistical notes
  • Discussion
  • Conclusions
  • References

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